JP6233978B2 - Wavelength conversion fired body - Google Patents

Description

  The present invention relates to a wavelength conversion fired body used together with a light emitting element such as a light emitting diode (LED) or a laser diode (LD).

LEDs are applied to mobile phones, various display devices, and the like from the viewpoints of power saving, long life, and small size. Furthermore, with the recent improvement in luminous efficiency, it has been attracting attention for lighting applications and is rapidly spreading.
At present, white LED lighting is mainly obtained by mixing white light emitted from a blue LED and light emitted from a phosphor that emits yellow light, which is a complementary color of blue, upon receiving the incident light of the blue light. It has become. Conventionally, a wavelength conversion member using such a phosphor is generally a phosphor in which a phosphor powder is dispersed in a resin. What was done is used a lot.

However, in LED lighting that requires a uniform emission color, the wavelength conversion member made of the ceramic composite has a problem that color unevenness is likely to occur.
In response to this, for example, in Patent Document 1, unevenness processing is performed on the surface of the member, whereby the wavelength-converted secondary light is reflected or refracted to be scattered in an irregular direction, thereby eliminating luminance unevenness and color unevenness. Wavelength conversion sintered bodies that can be described are described.
Specifically, by subjecting the sintered body of the inorganic substance and the phosphor to wet etching, the phosphor particles are preferentially dissolved, forming irregular irregularities on the surface, and separating the phosphor particles from the surface. It is described that the scattering property of the secondary light can be enhanced by the arrangement.

  As a conventional phosphor that emits yellow light upon receiving blue light used for white LED illumination, for example, a YAG (yttrium, aluminum, garnet) -based phosphor containing Ce (cerium) is known. When such YAG phosphor is irradiated with blue light, white light can be obtained by mixing the emitted blue light and the fluorescent color emitted from the YAG phosphor.

  Patent Document 2 proposes a semiconductor chip including the phosphor. The semiconductor chip disclosed in Patent Document 2 is mounted and used on, for example, an optoelectronic device. Specifically, as shown in FIG. 4, the optoelectronic device 50 has a semiconductor chip 52 disposed on a device casing 51 serving as a heat sink, and releases heat from the semiconductor chip 52 from the device casing 51. It has become.

As shown in FIG. 4, the semiconductor chip 52 includes a ceramic conversion element 55 disposed on the beam emission surface 54 of the semiconductor body 56. The ceramic conversion element 55 includes, for example, an active layer 58 made of a YAG: Ce-based garnet phosphor and a carrier layer 57 disposed thereabove. In addition, the arrow in FIG. 4 has shown the discharge | emission direction of heat.
Further, the active layer 58 and the carrier layer 57 will be described. The active layer 58 is made of a phosphor material (for example, YAG: Ce) doped with an activator (for example, Ce), and emits light in a predetermined wavelength region. It has a function of converting to light in other wavelength regions. The carrier layer 57 is made of a phosphor material (for example, YAG) that does not contain an activator.

  Further, in Patent Document 2, as the ceramic conversion element 55, as shown in FIG. 5, in order to suppress the diffusion of the activator (Ce) from the active layer 58 into the carrier layer 57, What is provided with the suppression layer 59 arrange | positioned between the support tanks 57 is proposed. The suppression layer 59 is made of, for example, aluminum oxide.

In the case of manufacturing the ceramic conversion element 55 described above, a green sheet to be each layer of the active layer 58 and the carrier layer 57 is formed with ceramic powder, a binder, and an additive, and after laminating these, sintering is performed. The ceramic conversion elements connected to each other can be manufactured.
Similarly, in the case of manufacturing the ceramic conversion element 55 including the suppression layer 59, green sheets that are the active layer 58, the carrier layer 57, and the suppression layer 59 are formed of ceramic powder, a binder, and an additive, After laminating them, the ceramic conversion elements connected to each other can be manufactured by sintering.

JP 2010-157637 A Special table 2014-504807 gazette

However, the wavelength conversion sintered body roughened by the etching process described in Patent Document 1 has an etching rate difference between the phosphor particles and the inorganic material, and therefore, mainly from the inorganic material as the phosphor particles dissolve. A surface layer is formed. As a result, a non-uniform distribution of the phosphor particle concentration can be made in the surface of the wavelength conversion sintered body, and it cannot be said that the color unevenness of the light emitted from the surface layer is sufficiently improved.
Moreover, the phosphor particles are eroded by the etching treatment, the crystallinity of the phosphor particle surface layer is lowered, and there is a technical problem that sufficient luminous efficiency cannot be obtained.
Furthermore, since the degree of unevenness on the surface of the inorganic material is severe, there is a technical problem that mechanical strength is low and cracking is likely to occur during mounting and use.

  The present invention has been made in order to solve the above technical problem, and has a wavelength that can suppress color unevenness of emitted light, has excellent luminous efficiency, and suppresses a decrease in mechanical strength. The object is to provide a converted fired body.

Moreover, when various evaluation and research were carried out about the ceramic conversion element (wavelength conversion baking body) described in the said patent document 2 provided with the suppression layer, it became clear that there existed the following technical problems.
First, the suppression layer in the ceramic conversion element obtained by laminating and sintering each layer (active layer, suppression layer, carrier layer) described in Patent Document 2 does not function sufficiently, There has been a technical problem that the activator diffuses from the active layer to the carrier layer and diffusion reduction is not sufficient. In particular, when the Ce concentration in the carrier layer exceeds 40 wt% of the Ce concentration in the active layer, the carrier layer also has an active (fluorescence) function, and is aimed at the light emitted from the carrier layer. It was difficult to obtain chromaticity.

Second, when the active layer is made of YAG: Ce and the suppression layer is made of Al ₂ O ₃ , the difference in refractive index between the active layer and the suppression layer becomes large. It has been found that there is a technical problem in that the amount of incident light reflected from the semiconductor body increases at the interface between the active layer and the suppression layer, and the light emission efficiency decreases due to an increase in return light.

Third, since the active layer and the carrier layer are formed of only the YAG material, the strength is low, and the difference in thermal expansion coefficient of Al ₂ O ₃ of the suppression layer interposed between the active layer and the carrier layer is small. Because of the difference, it has been found that there is a technical problem that cracking is likely to occur due to thermal stress at each interface.

Fourth, since the active layer is composed only of a YAG material, there is a technical problem that heat conductivity is low, heat generated from the semiconductor body is easily trapped in the active layer, and luminous efficiency is reduced. It has been found.
In addition, Patent Document 2 proposes an example in which Al ₂ O ₃ particles are mixed as a scattering agent in the carrier layer, but none of the above problems can be solved effectively.

In order to solve the first to fourth technical problems, the present inventors have laminated and sintered each layer (active layer, suppression layer, carrier layer) disclosed in Patent Document 2. The obtained ceramic conversion element (wavelength conversion fired body) was also studied earnestly.
As a result, the formed intermediate layer of _Al 2 _{O 3} the diameter of the _Al 2 _{O 3} of (inhibition layer) to a specific range, both the first layer and the (active layer) second layer (carrier layer), YAG-based Solving the above first to fourth technical problems by forming a layer made of a fluorescent material and Al ₂ O ₃ and forming a connection structure in which Al ₂ O ₃ particles are connected in each layer and at each layer interface As a result, the present inventors have conceived the present invention.

  The present invention provides the wavelength conversion fired body in which the intermediate layer is disposed between the first layer containing the activator-containing YAG-based fluorescent material and the second layer containing the YAG-based material. Suppresses the diffusion of the activator from the first layer to the second layer, has high heat dissipation, can emit light of a desired hue with high luminous efficiency, and has a high rigidity wavelength Another object is to provide a converted fired body.

The present invention has been made to solve the above technical problem, and in the wavelength conversion fired body according to the present invention, one main surface is a light incident surface, and a main surface opposite to the incident surface is present. It is a plate-like body that is an emission surface of light, and the plate-like body is composed of a fired body having a porosity of 1.0% or less composed of fluorescent material particles and translucent material particles containing an activator, and at least The entrance surface and the exit surface are fired surfaces on which the fluorescent material particles and translucent material particles are exposed unprocessed, and an arithmetic average roughness Ra of 10 points average at a measurement length of 4 mm is 0.1 μm or more. The arithmetic average roughness Ra1 of the average of 20 points at a measurement length of 1 μm of the fluorescent material particles exposed to the surface of the fired surface is 0.5 nm or less and 0.2 nm to 0.5 nm, and the surface of the fired surface is Arithmetic average roughness of 20-point average of exposed translucent material particles at a measurement length of 1 μm Ra2 is at 0.3nm or 0.7nm or less, wherein the fluorescent material has the general formula _{A 3 B 5 O 12: Ce} (A is Y, Gd, Tb, at least one selected from among Yb and Lu And B is at least one selected from Al, Ga and Sc.), And the translucent material is made of Al ₂ O ₃ or Al ₂ O ₃ with Sc ₂ O ₃ , It is a substance containing one kind selected from Ga ₂ O ₃ .

  According to such a wavelength conversion fired body according to the present invention, it is possible to suppress color unevenness of emitted light, to have excellent luminous efficiency, and to suppress a decrease in mechanical strength.

Here, the 20 average diameters d1 of the fluorescent material particles are 0.5 μm or more and 5 μm or less, and the 20 average diameters d2 of the translucent material particles are 1 μm or more and 10 μm or less, which are occupied by the fluorescent material particles. It is desirable that the ratio is 22 volume% or more and 35 volume% or less, and the ratio of the translucent material particles is 65 volume% or more and 78 volume% or less.
By comprising in this way, the wavelength conversion baking body with less color nonuniformity and higher luminous efficiency can be obtained.

Moreover, it is desirable that the 20 average diameters d1 of the fluorescent material particles be 0.1 to 0.78 times the 20 average diameters d2 of the light transmissive material particles.
By comprising in this way, the wavelength conversion baking body with few color irregularities can be obtained.

Furthermore, the arithmetic average roughness Ra2 of the average of 20 points at the measurement length of 1 μm of the translucent material particles exposed on the surface is the arithmetic average of the average of 20 points at the measurement length of 1 μm of the fluorescent material particles exposed on the surface. It is desirable that it is 1.2 times or more and 2.0 times or less of the roughness Ra1.
By comprising in this way, the wavelength conversion baking body which improved the luminous efficiency more can be obtained.

Further, the fluorescent material is a general formula A ₃ B ₅ O ₁₂ : Ce (A is at least one selected from Y, Gd, Tb, Yb and Lu, and B is Al, Ga and Sc. And the translucent material is selected from Al ₂ O ₃ or Al ₂ O ₃ and Sc ₂ O ₃ or Ga ₂ O _3. It is desirable that the substance contains.
By using these materials, it is possible to produce the wavelength conversion fired body made of a plate-like body more efficiently and reliably.
The wavelength conversion fired body is not limited to a single substance but may contain an activator diffusion suppression layer (intermediate layer) and a carrier layer.

Furthermore, the wavelength conversion fired body according to the present invention having an activator diffusion suppression layer (intermediate layer) inside includes a first layer composed of an activator-containing YAG-based fluorescent material and Al ₂ O _3, and the first layer. An intermediate layer made of Al ₂ O ₃ , in which particles having a diameter of 20 μm or more and 300 μm or less occupy 90% or more of the total number of particles and the intermediate layer are laminated, and the first layer is activated. and a second layer of YAG-based material and Al ₂ O ₃ containing 10% or less of the activator content of agents, together with Al ₂ O ₃ particles are connected with each other within each layer, each layer interface Also have a connection structure in which Al ₂ O ₃ particles are connected to each other, and the first layer, the intermediate layer, and the second layer are all from a fired body having a porosity of 1.0% or less. The surface of the first layer and the second layer is exposed unprocessed On the surface, the arithmetic average roughness Ra of 10 points average at a measurement length of 4 mm is 0.1 μm or more and 0.5 μm or less, and 20 points at a measurement length of 1 μm of the particles of the YAG-based fluorescent material exposed on the surface The average arithmetic average roughness Ra1 is 0.2 nm or more and 0.5 nm or less, and the 20-point average arithmetic average roughness Ra2 is 0.3 nm or more and 0 when the measured length of Al ₂ O ₃ particles exposed on the surface is 1 μm. and a .7nm less, the YAG fluorescent material activator-containing contained in the first _{layer, (Y 1-s Gd s} ) 3 (Al 1-t Ga t) 5 O 12: Ce (0 ≦ s ≦ 0.33, 0 ≦ t ≦ 0.2) .

  According to such a wavelength conversion fired body according to the present invention, it is possible to suppress the color unevenness of the emitted light, to have excellent luminous efficiency, and to suppress a decrease in mechanical strength, and the above In the wavelength conversion fired body in which the intermediate layer is disposed between the first layer containing the activator-containing YAG-based fluorescent material and the second layer containing the YAG-based material, The intermediate layer suppresses the diffusion of the activator from the first layer to the second layer, has high heat dissipation, can emit light of a desired hue with higher luminous efficiency, and is rigid. A high wavelength conversion fired body can be provided.

Here, 20 average diameters d1 of the particles of the YAG-based fluorescent material containing the activator in the first layer and the particles of the YAG-based material in the second layer are 0.5 μm or more and 5 μm or less. 20 average diameters d2 of the Al ₂ O ₃ particles in each of the two layers are 1 μm or more and 10 μm or less, and the particles of the activator-containing YAG-based fluorescent material in the first layer and the second layer The proportion of the YAG material particles in the layer is 22% by volume or more and 35% by volume or less in each of the first and second layers, and the proportion of the Al ₂ O ₃ particles is in the first layer and the second layer. It is preferable that it is 65 volume% or more and 78 volume% or less in each layer.
By setting the particle diameter and the content volume ratio as described above, the scattering property of the emitted light can be improved, the viewing angle dependency of the emitted light can be further reduced, and particularly the YAG fluorescence in the first layer. The in-plane color unevenness of the emitted light due to the heterogeneous distribution of the conductive material can be further reduced.

In addition, 20 average diameters d1 in each layer of the activator-containing YAG-based fluorescent material particles in the first layer and the YAG-based material particles in the second layer are 20 of the Al ₂ O ₃ particles. The average diameter d2 is preferably 0.1 times or more and 0.78 times or less.
By comprising in this way, the wavelength conversion baking body with few color irregularities can be obtained.

Further, the YAG-based fluorescent material containing an activator in the first layer in which the arithmetic average roughness Ra2 of 20-point average at a measurement length of 1 μm of the Al ₂ O ₃ particles exposed on the surface is exposed on the surface It is preferable that it is 1.2 times or more and 2.0 times or less of the arithmetic average roughness Ra1 of 20 points average at the measurement length of 1 μm in each layer of the particles of YAG and the particles of the YAG material in the second layer.
By comprising in this way, the wavelength conversion baking body which improved the luminous efficiency more can be obtained.

Further, when the volume composition ratio of the activator-containing YAG-based fluorescent material in the first layer, which is 100 as a whole, is a, the a is 22 to 35, and the second layer is 100 as a whole. When the volume composition ratio of the YAG-based material therein is b, it is more preferable that b is 25 to 40 and that b is larger than the a.
By using the wavelength conversion fired body so that the second layer is positioned on the upper surface of the light emitting element and irradiating blue light from the light emitting element, the blue light emitted from the light emitting element is a volume composition of the YAG-based material. When the first layer is more diffused and is irradiated to the first layer, the blue light is more uniformly diffused, the heat generated by local irradiation unevenness can be suppressed, and the luminous efficiency is further improved. Can be improved.

Furthermore, the first YAG fluorescent material activator-containing in the layer _{is, (Y 1 - s Gd s} ) 3 (Al 1 - t Ga t) 5 O 12: Ce (0 ≦ s ≦ 0. 33, 0 ≦ t ≦ 0.2).
With such a YAG-based fluorescent material, the wavelength conversion fired body can be more reliably produced, and the effects of the present invention described above can be made more remarkable.

According to the present invention, it is possible to obtain a wavelength conversion fired body that can suppress color unevenness of emitted light, has excellent luminous efficiency, and suppresses a decrease in mechanical strength.
Therefore, the wavelength conversion fired body according to the present invention can be suitably used for light emitting devices using LEDs, LDs, and the like, and is particularly suitable for obtaining stable white light emission without color unevenness in white LED lighting. It is.
Further, according to the present invention, the wavelength conversion baking in which the intermediate layer is further disposed between the first layer containing the activator-containing YAG-based fluorescent material and the second layer containing the YAG-based material. By forming a body, the intermediate layer suppresses the diffusion of the activator from the first layer to the second layer, and has high heat dissipation and emits light of a desired hue with high luminous efficiency. And a highly rigid wavelength conversion fired body can be obtained.

It is a schematic sectional drawing of the wavelength conversion baking body of 1st Embodiment which concerns on this invention. FIG. 2 is a cross-sectional view of the wavelength conversion fired body according to the second embodiment of the present invention. FIG. 3 is a cross-sectional view showing a state in which the wavelength conversion fired body of the second embodiment of FIG. 2 is arranged on a light emitting element. FIG. 4 is a cross-sectional view of a conventional optoelectronic device. FIG. 5 is a cross-sectional view of a wavelength conversion element provided in the optoelectronic device of FIG.

Hereinafter, a first embodiment of the present invention will be described in detail with reference to FIG.
FIG. 1 shows a cross-sectional view of a wavelength conversion fired body according to the present invention. As shown in FIG. 1, the wavelength conversion fired body 1 according to the present invention has a plate shape in which one main surface is a light incident surface 2 and a main surface opposite to the incident surface 2 is a light output surface 3. Is the body.

The plate-like body 1 is composed of a fired body having a porosity of 1.0% or less made of fluorescent material particles and translucent material particles containing an activator.
When the porosity exceeds 1.0%, not only the mechanical strength is lowered, but also the ratio of returning light to the incident surface 2 side is increased due to excessive scattering, resulting in a problem that the luminous efficiency is lowered. Therefore, a porosity of 1.0% or less is preferable.

Further, when white light emission is obtained in combination with a blue light emitting element or the like, the fluorescent material is selected from the general formula A ₃ B ₅ O ₁₂ : Ce (A is selected from Y, Gd, Tb, Yb, and Lu). And at least one selected from the group consisting of Al, Ga and Sc.), And the translucent material may be Al ₂ O ₃ or Al ₂ O. ₃ one is contained substance selected from among _{Sc 2 O 3, Ga 2 O} 3 is preferably used to.

In addition, the incident surface 2 and the exit surface 3 are fired surfaces on which the fluorescent material particles and the translucent material particles are exposed without being processed.
The fired surface refers to a surface that has been fired after forming the raw material powder, and is a surface that has not been subjected to processing such as mechanical grinding or etching after firing. If the entrance surface 2 and the exit surface 3 are subjected to processing such as mechanical grinding and etching after firing, so-called processed surfaces, the mechanical strength is low, and cracking due to thermal stress during mounting and use tends to occur. Moreover, there is a possibility that a defect that causes a decrease in light emission efficiency due to a defect generated during processing occurs.
Therefore, the incident surface 2 and the exit surface 3 are preferably fired surfaces.

  On the other hand, the four side surfaces other than the entrance surface 2 and the exit surface 3 (in FIG. 1, two side surfaces 4 and 5 are shown) have a thickness (vertical length, lateral length) between the side surfaces. In addition, even when the machined surface is used, the mechanical strength hardly decreases, and cracking due to thermal stress during mounting or use is unlikely to occur. In addition, since it is difficult to cause a decrease in light emission efficiency due to defects generated during processing, a processed surface may be used. Furthermore, in order to perform bonding or sintering bonding with the light emitting element with higher accuracy, it is preferable that the four side surfaces are subjected to processing such as mechanical grinding.

In addition, the fired surface on which the fluorescent material particles and the translucent material particles are exposed unprocessed has an arithmetic average roughness Ra of 10 points average at a measurement length of 4 mm of 0.1 μm to 0.5 μm.
The arithmetic average roughness Ra of 10 points average at a measurement length of 4 mm is 0.1 μm or more and 0.5 μm or less, which specifies a macro uneven state on the surface. In the place, 10 points of arithmetic average roughness Ra at a measurement length of 4 mm were measured, and this average value was taken.
If this Ra is less than 0.1 μm, reflection at the exit surface 3 increases and the light emission efficiency decreases, which is not preferable. On the other hand, if Ra exceeds 0.5 μm, it is not preferred between the opposing entrance surface 2 and exit surface 3. This is not preferable because the variation in thickness increases and unevenness in emission intensity from the exit surface 3 occurs.

  Four side surfaces (showing two side surfaces 4 and 5 in FIG. 1) other than the entrance surface 2 and the exit surface 3 are 10-point average arithmetic at a measurement length of 4 μm in order to improve adhesion to the sealing resin. The average roughness Ra is preferably 0.5 μm or more.

The arithmetic average roughness Ra1 of the average of 20 points at a measurement length of 1 μm of the fluorescent material particles exposed on the surface is 0.2 nm or more and 0.5 nm or less, and the measurement length of the transparent material particles exposed on the surface is 1 μm. The 20-point average arithmetic average roughness Ra2 is 0.3 nm or more and 0.7 nm or less.
The arithmetic average roughness Ra1 of the fluorescent material particles exposed on the surface, and the arithmetic average roughness Ra2 of the light transmissive material particles exposed on the surface are the respective values of the fluorescent material particles and the light transmissive material particles exposed on the surface. The irregularity state is specified, and an arithmetic average roughness Ra at a measurement length of 1 μm is measured for each particle, and an average value of 20 particles is obtained.

Making the arithmetic average roughness Ra1 of the fluorescent material particles less than 0.2 nm and making the arithmetic average roughness Ra2 of the translucent material particles less than 0.3 nm are difficult in production and productivity is low. Since it is inferior, it is not preferable.
Further, when the arithmetic average roughness Ra1 of the fluorescent material particles exceeds 0.5 nm and the arithmetic average roughness Ra2 of the translucent material particles exceeds 0.7 nm, the crystallinity is poor and crystal defects increase. . As a result, the luminous efficiency is reduced, which is not preferable.

The 20 average diameters d1 of the fluorescent material particles are 0.5 μm or more and 5 μm or less, and the 20 average diameters d2 of the translucent material particles are 1 μm or more and 10 μm or less.
The 20 average diameters d1 of the fluorescent material particles and the 20 average diameters d2 of the translucent material particles are one particle in any particle in a microscopic observation of an arbitrary cross section of the wavelength conversion fired body. The longest diameter and the shortest diameter are measured, the average value is calculated, and the average value is calculated after 20 of these are performed.

  The ratio of the fluorescent material particles is 22% by volume to 35% by volume, and the ratio of the translucent material particles is 65% by volume to 78% by volume.

  Thus, the average diameter of the fluorescent material particles and the translucent particles is within the above numerical range, and the content volume ratio of each of the fluorescent material particles is 22% by volume or more and 35% by volume or less. By making the fluorescent material particles 65 volume% or more and 78 volume% or less, the particles of the translucent material are absorbed and emitted by the specific wavelength light emitted from the light source (LED element) and the fluorescent material particles. It functions as the main light guide for specific wavelength light. As a result, a wavelength conversion fired body with less color unevenness and higher luminous efficiency is obtained.

Further, the 20 average diameters d1 of the fluorescent material particles are 0.1 times or more and 0.78 times or less than the 20 average diameters d2 of the translucent material particles.
When the 20 average diameters d1 of the fluorescent material particles are 0.1 times or more and 0.78 times or less than the 20 average diameters d2 of the translucent material particles, color unevenness can be further reduced. .

Further, the arithmetic average roughness Ra2 of the 20-point average at the measurement length of 1 μm of the translucent material particles exposed on the surface is the arithmetic average of the 20-point average at the measurement length of 1 μm of the fluorescent material particles exposed on the surface. The roughness Ra1 is 1.2 times or more and 2.0 times or less.
The translucent material particles serve as a main light guide path, but the arithmetic average roughness of the translucent material particles exposed at least on the emission surface 3 of the wavelength conversion fired body 1 is rougher than the fluorescent material particles at the ratio. By doing so, it is possible to more effectively emit both the specific wavelength light emitted from the light source (LED element) and the specific wavelength light absorbed and emitted by the fluorescent material particle, Luminous efficiency can be increased.

  The surface form of the fired body as described above can be measured by using an atomic force microscope (Dimension 5000 manufactured by Digital Instruments), using a silicon cantilever, and scanning the surface shape of each sample.

Further, the fluorescent material is a general formula A ₃ B ₅ O ₁₂ : Ce (A is at least one selected from Y, Gd, Tb, Yb and Lu, and B is Al, Ga and Sc) And the translucent material is selected from Al ₂ O ₃ or Al ₂ O ₃ and Sc ₂ O ₃ or Ga ₂ O _3. Is a substance containing.
By using each of the above materials, the effect of the wavelength conversion fired body made of the plate-like body can be obtained more reliably.

A more preferable material is a case where the activator is Ce, the fluorescent material is made of Y ₃ Al ₅ O ₁₂ , and the translucent material is made of Al ₂ O ₃ .
And from the composition material, in order to manufacture the wavelength converter fired body are all average particle _diameter, Y 2 _{O 3} raw material: 0.3 micron or 2μm or less, CeO ₂ material: 0.1 [mu] m or more 1μm or less, Al ₂ O ₃ raw material: 0.1 to 0.8 μm is preferably used, and firing is preferably performed in a vacuum atmosphere of about 1.0 × 10 ⁻² Pa or less in a medium vacuum to a low vacuum.
Thereby, the above-described wavelength conversion fired body according to the present invention can be produced more efficiently and reliably. In addition, the shaping | molding method and baking method, etc. in preparation of a sintered body are not specifically limited.

Next, a second embodiment of the present invention will be described in detail with reference to FIGS.
FIG. 2 is a cross-sectional view of the wavelength conversion fired body according to the present invention.
As shown in FIG. 2, the wavelength conversion fired body 11 is laminated on the first layer 12 that performs wavelength conversion, the intermediate layer 14 laminated on the first layer 12, and the intermediate layer 14. And a second layer 13 serving as a carrier layer of an LED (light emitting diode) or LD (laser diode). That is, the wavelength conversion fired body 11 is formed as a wavelength conversion laminate composite.
The first layer 12 is disposed on the beam emission surface of an LED (light emitting diode) or LD (laser diode). In other words, the wavelength conversion fired body (wavelength conversion laminate composite) 10 converts light having a predetermined wavelength incident from an LED or LD into a different wavelength in the first layer 12 and emits it.

The first layer 12 has a wavelength conversion function of converting a part of excitation light (specific wavelength) from an LED (light emitting diode) or LD (laser diode) into a wavelength longer than the wavelength and transmitting it.
Specifically, it is a layer composed of a YAG-based fluorescent material (for example, YAG: Ce) containing an activator (for example, Ce) and Al ₂ O ₃ . The wavelength conversion function layer such as the first layer 12 is adjusted in wavelength or the like for converting excitation light according to the composition of the fluorescent material substrate, the type and content of the activator, the thickness of the layer, and the like (chromaticity Designed).
More particularly, the YAG fluorescent material of the _{activator-containing, (Y 1 - s Gd s} ) 3 (Al 1 - t Ga t) 5 O 12: Ce, where 0 ≦ s ≦ 0.33, It is desirable that ≦ t ≦ 0.2. With such a YAG-based fluorescent material, the wavelength conversion fired body (wavelength conversion laminated composite) 11 can be more reliably manufactured, The invention effect can be made more remarkable.

Further, as described above, the intermediate layer 14 made of Al ₂ O ₃ is provided between the first layer 12 and the second layer 13. When the intermediate layer 14 is used to produce the wavelength conversion fired body 11, the green sheets to be the layers 12 to 14 are sequentially laminated and then fired and integrated, so that the activator in the first layer 12 is the first in the firing step. 2 to suppress diffusion into the second layer 13.
That is, when the activator contained in the first layer 12 diffuses into the second layer 13, the content of the activator in the first layer 12 is reduced from the intended amount, and the conversion wavelength is shifted. Arise. Further, since the second layer 13 is doped with the activator, the second layer 13 also partially converts the excitation light, and as a result, the overall chromaticity of the emitted light cannot be achieved as designed. The problem arises. In order to solve these problems, the intermediate layer 14 is provided.

Further, the intermediate layer 14 is formed by _Al 2 _{O 3,} the _Al 2 _O The number of particles diameter 20μm or 300μm below _3, is configured to occupy the _Al 2 _{O 3} of the total number of particles in 90% Yes.
By thus the green sheet the _Al 2 300 [mu] m or less in particle number diameter 20μm or more _{O 3} after firing step is completed the stack is fired to occupy the _Al 2 _{O 3} of the total number of particles in 90% The diffusion of the activator from the first layer 12 to the second layer 13 can be sufficiently reduced. In addition, it becomes possible to suppress the diffusion of the activator in the reheating process such as film formation and adhesion after firing.

The diameter of the Al ₂ O ₃ particles forming the intermediate layer 14 is more preferably 5 μm or more and 500 μm or less. If the diameter of such Al ₂ O ₃ particles, the diffusion of the activator can be more effectively suppressed, and the decrease in mechanical strength associated with the excessive particles can be suppressed. it can.
Further, the intermediate layer 14 preferably has a porosity of 1.0% or less, and pores having a diameter of 0.3 μm or more and 3 μm or less are more uniformly distributed, thereby more reliably preventing cracking due to thermal stress. can do. In order to obtain this effect more reliably, the porosity is more preferably 0.1% or more and 1.0% or less.

The second layer 13 is made of the same material as the first layer 12 except for the presence or absence of an activator, specifically, a YAG-based material that is 10% or less of the activator content of the first layer 12. It consists of Al ₂ O ₃ .
By forming the second layer 13 in this way, when the wavelength conversion fired body (wavelength conversion laminated composite) 10 is used as an LED lamp or an LD lamp, The occurrence of warpage can be suppressed.

The volume composition ratio between the YAG fluorescent material and Al ₂ O ₃ in the first layer 12 is 22% to 35% by volume of YAG fluorescent material and 65% by volume of Al ₂ O _3. It is in the range of not less than 78% by volume .
The volume composition ratio between the YAG-based material and Al ₂ O ₃ in the second layer 13 is 22% to 35% by volume for YAG-based material, and 65% to 78% by volume for Al ₂ O _3. Within the following range.
Further, the first layer 12, second layer 13, together with the _Al 2 _{O 3} grains in each layer of the intermediate layer 14 is connected, is _Al 2 _{O 3} grains even at the interface of each layer 12, 13, 14 It has a connecting structure to be connected.
That is, the wavelength conversion fired body (wavelength conversion laminate composite) 11 has a structure in which the first layer 12 having the above composition ratio and the second layer 13 sandwich the intermediate layer 14 made of Al ₂ O _3. There also the three layers has a connection structure between the _Al 2 _{O 3,} and a connecting structure between the _Al 2 _{O 3} even in each layer interface.

In particular, each of the first layer 12 and the second layer 13 has sufficient strength because it contains Al ₂ O ₃ at a predetermined composition ratio, and thermal stress during use accompanying a difference in thermal expansion coefficient between the respective layers. It is possible to suppress the occurrence of cracks due to. In order to further reduce the occurrence of this crack, it is preferable to make the Al ₂ O ₃ volume composition ratio of the first layer 12 and the second layer 13 uniform within ± 5% by volume. Moreover, since the heat dissipation in the 1st layer 12 improves, the fall of the light emission efficiency by heat soaking can also be suppressed. In addition, heat dissipation to a heat sink such as an LED package can be excellent.

In addition, since the Al ₂ O ₃ particles are connected to each other at the interfaces of the layers 12, 13, and 14, it is possible to reduce the amount of light interface reflection caused by the difference in refractive index between the layers. As a result, a decrease in luminous efficiency can be suppressed. In addition, since the Al ₂ O ₃ particles are connected to each other, a decrease in heat generation efficiency due to the heat accumulation in the first layer 12 can be suppressed. Moreover, the heat dissipation to the device casing as a heat sink can also be improved.

  Note that “volume composition ratio (volume%) × thickness (μm) of YAG-based fluorescent material included in the first layer 12” is A (vol% · μm), and “included in the second layer 3”. Assuming that “volume composition ratio (volume%) × thickness (μm) of YAG-based material” is B (volume% · μm), A / B is more preferably 0.024 or more and 5 or less. By satisfying other conditions and further forming in this range, it is possible to more reliably reduce warpage that occurs during use. In order to further enhance this effect, the A / B is more preferably 0.083 to 0.360.

The YAG fluorescent material contained in the first layer 12 and the YAG material contained in the second layer 13 have an average particle size of 0.5 μm or more and 5 μm or less. The average particle diameter of Al ₂ O ₃ contained in the second layer 13 is 1 μm or more and 10 μm or less.
By setting the particle size as described above, the scattering property of the emitted light is improved, the color unevenness at the viewing angle can be further reduced, and in particular, the heterogeneity of the YAG-based fluorescent material in the first layer The in-plane color unevenness of the emitted light accompanying the distribution can be further reduced.

Further, when the volume composition ratio of the activator-containing YAG fluorescent material in the first layer 2 is a, a is 22 to 35, and the volume composition of the YAG material in the second layer 3 is When the ratio is b, it is more preferable that b is 25 to 40 and the b is larger than the a.
By using the wavelength conversion fired body (wavelength conversion laminate composite) as shown in FIG. 3 such that the second layer 13 is positioned on the upper surface of the light emitting element 15 and is irradiated with blue light from the light emitting element. The blue light emitted from the light emitting element is more diffused in the second layer 13 having a large volume composition ratio of the YAG-based material, and the blue light is more uniformly diffused when irradiated to the first layer 12. Thus, heat generation due to local irradiation unevenness can be suppressed, and the light emission efficiency can be further improved.
In the second embodiment as well, as described in the first embodiment, the surfaces of the first layer 12 and the second layer 13 are unfired exposed surfaces and have a measurement length of 4 mm. The arithmetic average roughness Ra of 10 points averages from 0.1 μm to 0.5 μm, and the average of 20 points of the YAG-based fluorescent material particles exposed on the surface and the measured length of 1 μm of the YAG-based material is calculated. The average roughness Ra1 is 0.2 nm or more and 0.5 nm or less, and the arithmetic average roughness Ra2 of 20 points average at a measurement length of 1 μm of the Al ₂ O ₃ particles exposed on the surface is 0.3 nm or more and 0.7 nm or less. Is formed.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example, this invention is not restrict | limited by the following Example.

(Preparation of Y ₃ Al ₅ O ₁₂ : Ce + Al ₂ O ₃ fired sample)
Cerium oxide powder having an average particle size of 0.5 μm and a purity of 99.9%; yttrium oxide powder having an average particle size of 1.2 μm and a purity of 99.9%; and oxidation having an average particle size of 0.4 μm and a purity of 99.9% Aluminum powder was mixed at a predetermined blending ratio to obtain a raw material powder.
Ethanol, polyvinyl butyral (PVB) binder and glycerin plasticizer were added to the raw material powder, and pulverized and mixed in a ball mill using aluminum oxide balls for 40 hours to prepare a slurry.

Using this slurry, a green sheet having a predetermined thickness was formed by a doctor blade method. The obtained green sheet was degreased and calcined in the air, and then fired in a vacuum atmosphere of 1.0 × 10 ⁻² Pa or less to prepare a Y ₃ Al ₅ O ₁₂ : Ce + Al ₂ O ₃ fired body ( Examples 1 to 18 and Comparative Examples 1 to 5).
In addition, the porosity of Y ₃ Al ₅ O ₁₂ : Ce + Al ₂ O ₃ fired body, the arithmetic average roughness of 10 points average at a measurement length of 4 mm on the fired surface, the measurement length of fluorescent material particles and translucent material particles 1 μm The 20-point average arithmetic average roughness, the 20 average diameters of the fluorescent material particles and the light-transmitting material particles in the range of 1500 ° C. to 1750 ° C., Y ₂ O ₃ raw material, and CeO ₂ raw material , and an average particle size of the Al ₂ O ₃ raw material in the above range, was prepared made in Table 1 by properly changing.

Moreover, in Comparative Example 3, a Y ₃ Al ₅ O ₁₂ : Ce + Al ₂ O ₃ fired body was produced under the same conditions as in Example 11, and then the incident surface and the exit surface were mirror-finished using a 3 μm diamond slurry. Was given.
Furthermore, in Comparative Example 4, a Y ₃ Al ₅ O ₁₂ : Ce + Al ₂ O ₃ fired body was produced under the same conditions as in Example 14, and thereafter the incident surface and the exit surface were fixed abrasive of # 200 (mesh). The grains were ground by a surface grinding machine.
Further, in Comparative Example 5, a Y ₃ Al ₅ O ₁₂ : Ce + Al ₂ O ₃ fired body was produced under the same conditions as in Example 15, and thereafter, the incident surface and the output surface were heated concentrated sulfuric acid (25% H ₂ Etching was performed at SO ₄ , 150 ° C.).
Tables 1 and 2 show Examples 1 to 18 and Comparative Examples 1 to 5, respectively.

(Preparation of Y ₂ Gd ₁ Al ₅ O ₁₂ : Ce + Al ₂ O ₃ fired sample)
Cerium oxide powder having an average particle size of 0.5 μm and a purity of 99.9%; yttrium oxide powder having an average particle size of 1.2 μm and a purity of 99.9%; and oxidation having an average particle size of 0.5 μm and a purity of 99.9% Gadolinium powder and aluminum oxide powder having an average particle size of 0.4 μm and a purity of 99.9% were mixed at a predetermined blending ratio to obtain a raw material powder.
Ethanol, polyvinyl butyral (PVB) binder and glycerin plasticizer were added to the raw material powder, and pulverized and mixed in a ball mill using aluminum oxide balls for 40 hours to prepare a slurry.
Using this slurry, a green sheet having a predetermined thickness was formed by a doctor blade method. The obtained green sheet is degreased and calcined in the air, and then fired in a vacuum atmosphere of 1.0 × 10 ⁻² Pa or less to produce a Y ₂ Gd ₁ Al ₅ O ₁₂ : Ce + Al ₂ O ₃ fired body. did.
And the sintered body concerning Example 19- Example 36 and Comparative Example 6- Comparative Example 10 was obtained. Tables 3 and 4 show Examples 19 to 36 and Comparative Examples 6 to 10.
Incidentally, the change of the characteristic values in the examples 19 to Example 36 and Comparative Examples 6 and 7, the above-mentioned _Y 3 _Al 5 _O 12: it was performed in the same manner as in the Ce + _Al 2 _{O 3} sintered body. Comparative Example 8 (Y ₂ Gd ₁ Al ₅ O ₁₂ equivalent to Example 31: Ce + Al ₂ O ₃ fired body), Comparative Example 9 (Y ₂ Gd ₁ Al ₅ O ₁₂ equivalent to Example 36: Ce + Al ₂ O ₃ Fired body) and Comparative Example 10 (Y ₂ Gd ₁ Al ₅ O ₁₂ : Ce + Al ₂ O ₃ fired body equivalent to Example 25) are mirror-finished and ground under the same conditions as in Comparative Examples 3, 4 and 5. Etching was applied.

(Preparation of Lu ₃ Al ₅ O ₁ : Ce + Al ₂ O ₃ fired body sample)
Cerium oxide powder having an average particle size of 0.5 μm and a purity of 99.9%, lutetium oxide powder having an average particle size of 1.7 μm and a purity of 99.9%, and oxidation having an average particle size of 0.4 μm and a purity of 99.9% Aluminum powder was mixed at a predetermined blending ratio to obtain a raw material powder.
Ethanol, polyvinyl butyral (PVB) binder and glycerin plasticizer were added to the raw material powder, and pulverized and mixed in a ball mill using aluminum oxide balls for 40 hours to prepare a slurry.
Using this slurry, a green sheet having a predetermined thickness was formed by a doctor blade method. The obtained green sheet was degreased and calcined in the air, and then fired in a vacuum atmosphere of 1.0 × 10 ⁻² Pa or less to prepare a Lu ₂ Al ₅ O ₁₂ : Ce + Al ₂ O ₃ fired body ( Example 37). Example 37 is shown in Tables 5 and 6.

(Production of Y ₃ Ga ₁ Al ₄ O ₁ : Ce + Al ₂ O fired body sample)
Cerium oxide powder having an average particle size of 0.5 μm and a purity of 99.9%; yttrium oxide powder having an average particle size of 1.2 μm and a purity of 99.9%; and gallium oxide powder having an average particle size of 2 μm and a purity of 99.9% And an aluminum oxide powder having an average particle size of 0.4 μm and a purity of 99.9% were mixed at a predetermined blending ratio to obtain a raw material powder.
Ethanol, polyvinyl butyral (PVB) binder and glycerin plasticizer were added to the raw material powder, and pulverized and mixed in a ball mill using aluminum oxide balls for 40 hours to prepare a slurry.
Using this slurry, a green sheet having a predetermined thickness was formed by a doctor blade method. The obtained green sheet is degreased and calcined in the air, and then fired in a vacuum atmosphere of 1.0 × 10 ⁻² Pa or less to produce a Y ₃ Ga ₁ Al ₄ O ₁₂ : Ce + Al ₂ O ₃ fired body. (Example 38). Example 38 is shown in Tables 5 and 6.

(Preparation of a sample of Lu ₃ Sc ₁ Al ₄ O ₁₂ : Ce + Al ₂ O ₃ fired body)
Cerium oxide powder having an average particle size of 0.5 μm and a purity of 99.9%; lutetium oxide powder having an average particle size of 1.7 μm and a purity of 99.9%; and oxidation having an average particle size of 0.3 μm and a purity of 99.9% Scandium powder and aluminum oxide powder having an average particle size of 0.4 μm and a purity of 99.9% were mixed at a predetermined blending ratio to obtain a raw material powder.
Ethanol, polyvinyl butyral (PVB) binder and glycerin plasticizer were added to the raw material powder, and pulverized and mixed in a ball mill using aluminum oxide balls for 40 hours to prepare a slurry.
Using this slurry, a green sheet having a predetermined thickness was formed by a doctor blade method. The obtained green sheet is degreased and calcined in the air, and then fired in a vacuum atmosphere of 1.0 × 10 ⁻² Pa or less to produce a Lu ₃ Sc ₁ Al ₄ O ₁ : Ce + Al ₂ O ₃ fired body. (Example 39). Example 39 is shown in Tables 5 and 6.

(Preparation of a sample of Lu ₃ Ga ₁ Al ₄ O ₁₂ : Ce + Al ₂ O ₃ fired body)
Cerium oxide powder having an average particle size of 0.5 μm and purity of 99.9%, lutetium oxide powder having an average particle size of 1.7 μm and purity of 99.9%, and gallium oxide powder having an average particle size of 2 μm and purity of 99.9% And an aluminum oxide powder having an average particle size of 0.4 μm and a purity of 99.9% were mixed at a predetermined mixing ratio to obtain a raw material powder.
Ethanol, polyvinyl butyral (PVB) binder and glycerin plasticizer were added to the raw material powder, and pulverized and mixed in a ball mill using aluminum oxide balls for 40 hours to prepare a slurry.
Using this slurry, a green sheet having a predetermined thickness was formed by a doctor blade method. The obtained green sheet is degreased and calcined in the air, and then fired in a vacuum atmosphere of 1.0 × 10 ⁻² Pa or less to produce a Lu ₃ Ga ₁ Al ₄ O ₁₂ : Ce + Al ₂ O ₃ fired body. (Example 40). Example 40 is shown in Tables 5 and 6.

(Preparation of a sample of Y ₃ Sc ₁ Al ₄ O ₁₂ : Ce + Al ₂ O ₃ fired body)
Cerium oxide powder having an average particle size of 0.5 μm and a purity of 99.9%; yttrium oxide powder having an average particle size of 1.2 μm and a purity of 99.9%; and oxidation having an average particle size of 0.3 μm and a purity of 99.9% Scandium powder and aluminum oxide powder having an average particle size of 0.4 μm and a purity of 99.9% were mixed at a predetermined blending ratio to obtain a raw material powder.
Ethanol, polyvinyl butyral (PVB) binder and glycerin plasticizer were added to the raw material powder, and pulverized and mixed in a ball mill using aluminum oxide balls for 40 hours to prepare a slurry.
Using this slurry, a green sheet having a predetermined thickness was formed by a doctor blade method. The obtained green sheet is degreased and calcined in the air, and then fired in a vacuum atmosphere of 1.0 × 10 ⁻² Pa or less to produce a Y ₃ Sc ₁ Al ₄ O ₁₂ : Ce + Al ₂ O ₃ fired body. (Example 41). Example 41 is shown in Tables 5 and 6.

(Preparation of a sample of Tb ₃ Al ₅ O ₁₂ : Ce + Al ₂ O ₃ fired body)
Cerium oxide powder having an average particle size of 0.5 μm and a purity of 99.9%, terbium oxide powder having an average particle size of 0.7 μm and a purity of 99.9%, and oxidation having an average particle size of 0.4 μm and a purity of 99.9% Aluminum powder was mixed at a predetermined blending ratio to obtain a raw material powder.
Ethanol, polyvinyl butyral (PVB) binder and glycerin plasticizer were added to the raw material powder, and pulverized and mixed in a ball mill using aluminum oxide balls for 40 hours to prepare a slurry.
Using this slurry, a green sheet having a predetermined thickness was formed by a doctor blade method. The obtained green sheet was degreased and calcined in the air, and then fired in a vacuum atmosphere of 1.0 × 10 ⁻² Pa or less to prepare a Tb ₃ Al ₅ O ₁₂ : Ce + Al ₂ O ₃ fired body ( Example 42). Example 42 is shown in Tables 5 and 6.

(Preparation of Yb ₃ Al ₅ O ₁₂ : Ce + Al ₂ O ₃ fired body sample)
Cerium oxide powder having an average particle size of 0.5 μm and a purity of 99.9%; ytterbium oxide powder having an average particle size of 0.4 μm and a purity of 99.9%; and oxidation having an average particle size of 0.4 μm and a purity of 99.9% Aluminum powder was mixed at a predetermined blending ratio to obtain a raw material powder.
Ethanol, polyvinyl butyral (PVB) binder and glycerin plasticizer were added to the raw material powder, and pulverized and mixed in a ball mill using aluminum oxide balls for 40 hours to prepare a slurry.
Using this slurry, a green sheet having a predetermined thickness was formed by a doctor blade method. The obtained green sheet was degreased and calcined in the air, and then fired in a vacuum atmosphere of 1.0 × 10 ⁻² Pa or less to prepare a Yb ₃ Al ₅ O ₁₂ : Ce + Al ₂ O ₃ fired body ( Example 43). In addition, Example 43 is shown in Tables 5 and 6.
Note that changing the characteristic values in the examples 37 to example 43, the above-described _Y 3 _Al 5 _O 12: was performed in the same manner as in the Ce + _Al 2 _{O 3} sintered body. In addition, the four side surfaces other than the incident surface 2 and the emission surface 3 in the fired bodies of Examples 1 to 43 and Comparative Examples 1 to 10 are ground by a surface grinding machine using # 150 (mesh) fixed abrasive grains. In any of the side surfaces, the arithmetic average roughness Ra of 20 points at a measurement length of 100 μm was in the range of 0.5 to 1.5 μm.

(Measurement of each example and each comparative example)
And about each Example and each comparative example, porosity, arithmetic average roughness Ra1, Ra2 of 20 points average, average surface roughness Ra of an entrance surface and the said output surface, content ratio of fluorescent material and translucent material The 20 average diameters d1 of the fluorescent material particles and the 20 average diameters d2, the luminous efficiency and the emission unevenness of the translucent material particles were measured.

  The porosity was measured by Archimedes method (JIS C 2141).

The arithmetic average roughness Ra1 and Ra2 of 20-point average of Y ₃ Al ₅ O ₁₂ : Ce particles and Al ₂ O ₃ particles exposed on the surface is a cantilever (silicon cantilever having a spring constant of 3 N / m and a resonance frequency of 75 kHz. ) Using an atomic force microscope (Dimension 5000, manufactured by Digital Instruments) in AC mode (tapping mode), and scanning the surface shape of each sample.

  The measurement was performed by scanning a standard scanner with a maximum range of 10 μm square, and then the field of view was narrowed (enlarged) to reflect the characteristics of the surface shape. The arithmetic average roughness was calculated with a length of 1 μm. Ra2 / Ra1 was determined from the measured Ra1 and Ra2.

  Further, the arithmetic average roughness Ra of the incident surface and the exit surface was measured with a contact surface roughness measuring machine at a measurement length of 4 μm (JIS B0601-2001).

  In addition, the content ratio of the fluorescent material and the translucent material is measured by powder X-ray analysis of a sample in which the mixing amount of the raw material powder applied to the fluorescent material and the raw material powder applied to the translucent material is changed, A calibration curve was created from the peak intensity ratio of the fluorescent material and the translucent material. Then, the measurement sample was measured and the ratio of a fluorescent material and a translucent material was computed.

  The 20 average diameters d1 of the fluorescent material particles and the 20 average diameters d2 of the translucent material particles specify the fluorescent phase and the translucent phase based on the reflected electron image of the FE-SEM. It was measured. In addition, the diameter of one particle | grain was made into the value which measured the longest diameter and the shortest diameter, and divided this by 2.

Further, the luminous efficiency was fixed to a blue LED element (light emitting area 1 mm square, emission wavelength 460 nm) with a silicone resin after processing to 1 mm square and a thickness of 0.1 mm. After collecting the luminescence with an integrating sphere, the emission spectrum was measured using a spectroscope (“USB4000 Fiber Melch Channel Spectrometer” manufactured by Ocean Optics).
The emission intensity normalized by the emission peak wavelength and the absorption amount was calculated from the obtained spectrum. The emission intensity was set to 100 based on the measurement result of a commercially available YAG: Ce phosphor (“P46-Y3” manufactured by Kasei Optonix).

Light emission unevenness is processed to 1mm square, thickness 0.1mm, and then irradiated with blue LED light condensed to 0.3mm in diameter from the back. Spectrometer ("USB4000 Fiber Melch Channel Spectrometer" manufactured by Ocean Optics) from the front. ).
CIEx was calculated from the obtained spectrum data. The values shown in the table indicate standard deviations when measuring 51 × 51 (2601 points) at a 0.1 mm pitch in a 5 mm square area.
The measurement results are shown in Tables 1-6.

The wavelength conversion material (Comparative Example 5) obtained by etching the surface of the fired body described as a conventional example has low mechanical strength and large color unevenness.
In addition, the wavelength conversion material (Comparative Example 4) subjected to the grinding process instead of the above etching process had the same mechanical strength and color unevenness as those of Comparative Example 5. Moreover, the grinding | polishing process was performed.
The wavelength conversion material (Comparative Example 3) had a low luminous efficiency.
On the other hand, as can be seen from Table 1 and Table 2, the porosity is 1.0% or less, the arithmetic average roughness Ra of 10 points average at a measurement length of 4 mm on the fired surface is 0.1 μm to 0.5 μm, the surface In the present invention, the 20-point average arithmetic average roughness Ra of the fluorescent material particles and translucent material particles exposed to 1 μm is 0.2 nm to 0.5 nm and 0.3 nm to 0.7 nm, respectively. It was confirmed that the wavelength conversion fired bodies (Examples 1 to 3) had higher luminous efficiency and smaller color unevenness than those outside these numerical ranges (Comparative Examples 1 and 2).

Further, the 20 average diameters of the fluorescent material particles and the translucent material particles are d1: 0.5-5 μm and d2: 1-10 μm, respectively, and the proportion of each particle is 22-35% by volume, 65-65, respectively. It was confirmed that the wavelength conversion fired body (Examples 5 to 7) of the present invention having 78% by volume has higher luminous efficiency and smaller color unevenness than those of Examples 1 to 3.
Further, the wavelength conversion fired body of the present invention in which the 20 average diameters d1 of the fluorescent material particles are 0.1 to 0.78 times the 20 average diameters d2 of the light transmissive material particles (Examples 10 to 12). ) Is confirmed to be even smaller in color unevenness than the above Examples 5 to 7, and the arithmetic average roughness Ra2 of the 20-point average at a measurement length of 1 μm of the translucent material particles is set to be the same as that of the fluorescent material particles. It was confirmed that the luminous efficiency was further improved by setting the Ra1 to 1.2 to 2.0 times.

Also, in the case of the wavelength conversion fired body using Y ₂ Gd ₁ Al ₅ O ₁₂ : Ce as the fluorescent material from Table 3 and Table 4, the same as in the case of Y ₃ Al ₅ O ₁₂ : Ce described above. Was confirmed.
Moreover, _Lu from Tables 5 and 6 as a fluorescent material _{3 Al 5 O 12: Ce,} Lu 3 Ga 1 Al 4 O 12: Ce, Y 3 Sc 1 Al 4 O 12: Ce, Lu 3 Ga 1 Al 4 O ₁₂ : Ce, Y ₃ Sc ₁ Al ₄ O ₁₂ : Ce, Tb ₃ Al ₅ O ₁₂ : Ce, Yb ₃ Al ₅ O ₁₂ : Also in the case of a wavelength fired body using Ce, good light emission efficiency and small color unevenness It was confirmed that

  Hereinafter, although the 2nd Embodiment of this invention is described more concretely based on an Example, this invention is not restrict | limited by the following Example.

(Preparation of first layer green sheet)
The first layer in the second embodiment corresponds to the wavelength conversion fired body of the first embodiment.
That is, a cerium oxide powder with an average particle size of 0.3 to 1.5 μm and a purity of 99.9%, an yttrium oxide powder with an average particle size of 0.6 to 5 μm and a purity of 99.9%, and an average particle size of 0.2 to A predetermined amount of 0.9 μm-purified aluminum oxide powder having a purity of 99.9% was blended so as to have a composition after firing under the firing conditions described later as shown in Table 7 to obtain a raw material powder.
Ethanol, a PVB binder and a glycerin plasticizer were added to the raw material powder to the raw material powder, and pulverized and mixed by a ball mill using aluminum oxide balls for 10 hours to prepare a slurry.
And the green sheet of the predetermined thickness shown in Table 7 was produced from the obtained slurry by the doctor blade method. Next, the produced green sheet was punched into a 100 mm mouth.

(Production of intermediate layer green sheet)
An aluminum oxide powder having an average particle size of 0.3 to 2.1 μm and a purity of 99.9% was used as a raw material powder. It selected so that the diameter of the aluminum oxide particle after baking on the baking conditions etc. which are described later may become in the range of the minimum value shown in Table 8, and the minimum value.
Ethanol, PVB binder and glycerin plasticizer were added to the raw material powder to the raw material powder, and pulverized and mixed for 10 hours by a ball mill using aluminum oxide balls to prepare a slurry.
And the green sheet of the predetermined thickness shown in Table 8 was produced from the obtained slurry by the doctor blade method. Next, the produced green sheet was punched into a 100 mm mouth.

(Preparation of second layer green sheet)
An yttrium oxide powder having a purity of 99.9% and an average particle size of 0.6 to 5 μm, and an aluminum oxide powder having a purity of 99.9% and an average particle size of 0.2 to 0.9 μm, as shown in Table 9, A predetermined amount was blended so as to obtain a composition after firing under the firing conditions to be described to obtain a raw material powder.
Ethanol, a PVB binder and a glycerin plasticizer were added to the raw material powder to the raw material powder, and pulverized and mixed by a ball mill using aluminum oxide balls for 10 hours to prepare a slurry.
And the green sheet of the predetermined thickness shown in Table 9 was produced from the obtained slurry by the doctor blade method. Next, the produced green sheet was punched into a 100 mm mouth.

(Creation of wavelength conversion laminate composite (wavelength conversion fired body))
After punching the first layer, the intermediate layer, and the second layer, the green sheet for the intermediate layer is sandwiched between the green sheet for the first layer and the green sheet for the second layer. The laminate was made.
Subsequently, a warm isostatic pressing method (WIP) was performed in an atmosphere of 60 ° C. and 100 MPa to produce a molded body having a laminated structure.
And after the degreasing calcining in air | atmosphere, the produced molded object was baked at 1550-1750 degreeC in the vacuum atmosphere, and the wavelength conversion laminated composite (wavelength conversion baking body) was obtained (Example 44- Example 53, Comparative Examples 11-19).

[Measurement and evaluation of each example and each comparative example]
(Measurement of porosity, etc.)
In the same manner as the examples and comparative examples according to the first embodiment of the present invention, the porosity and the arithmetic average roughness Ra1 of the 20-point average for the examples and comparative examples according to the second embodiment of the present invention. , Ra2, average surface roughness Ra, 20 average diameter d2, YAG-based fluorescent material and the content ratio of _Al 2 _{O 3} of 20 average diameter d1 and Al ₂ O particles YAG fluorescent material particles, YAG-based materials And the content ratio of Al ₂ O ₃ were measured. The results are shown in Tables 7, 8, and 9.
(Presence or absence of connection between Al ₂ O ₃ particles)
Example 44 to Example 53 and Comparative Examples 11 to 19, connexion and verified the presence or absence of the connection between the _Al 2 _{O 3} particles in each layer and each layer interface.
The presence or absence of connection between Al ₂ O ₃ particles at each layer and each layer interface was determined by observing an arbitrary vertical cross section in the thickness direction of the wavelength conversion laminate composite with an SEM (scanning electron microscope), and Al _{2 at} each layer and each layer interface. It was confirmed whether or not O ₃ particles were connected (bonded). The results are shown in Table 10.

(Measurement of the number of Al ₂ O ₃ particles and each particle size)
When an arbitrary vertical cross section in the thickness direction of the wavelength conversion laminate composite is observed with an SEM (scanning electron microscope) and the intermediate layer portion is imaged with a total viewing angle of 1 mm ² , the number of Al ₂ O ₃ particles and each particle The diameter was measured. The results are shown in Table 8.

(Measurement of Ce concentration (atom%) in first layer and second layer after firing)
The Ce concentration (atom%) in the first layer and the second layer after firing was measured by ICP emission analysis after each layer was cut out by grinding.

(Measurement of uneven color)
Color unevenness is processed into 1 mm square, irradiated with blue LED light condensed to a diameter of 0.3 mm from the back, and received from the front using a spectroscope ("USB4000 Fiber Melch Channel Spectrometer" manufactured by Ocean Optics). .
CIEx was calculated from the obtained spectrum data. The values shown in Table 5 indicate standard deviations when measuring 51 × 51 (2601 points) at a 0.1 mm pitch in a 5 mm square area.

(Measurement of chromaticity (fluorescence peak wavelength) and luminous efficiency)
The chromaticity and luminous efficiency were processed to 1 mm square and then fixed with a silicone resin on a blue LED element (light emitting area 1 mm square, emission wavelength 460 nm). After collecting the luminescence with an integrating sphere, the emission spectrum was measured using a spectroscope (“USB4000 Fiber Melch Channel Spectrometer” manufactured by Ocean Optics).
The emission intensity normalized by the measurement of the fluorescence peak wavelength and the amount of absorption was calculated from the obtained spectrum. The fluorescence peak wavelength becomes shorter as Ce diffuses in the second layer. In order to obtain desired white light (8000 K or less) in combination with blue light, the emission peak wavelength needs to be 540 nm or more.
Luminous intensity (luminous efficiency) was set to 100 as a measurement result of a commercially available YAG: Ce phosphor (“P46-Y3” manufactured by Kasei Optonix).

As a result, as in Examples 44 to 53, particles having a diameter of 20 μm or more and 300 μm or less occupy 90% or more of the total number of particles in the intermediate layer formed of Al ₂ O ₃ , so that the second after firing It was confirmed that the Ce (activator) concentration in the layer can be made sufficiently low, and the diffusion of Ce (activator) into the second layer can be suppressed.
Further, as in Examples 44 to 53, the first layer, the intermediate layer, and the second layer are all made of a fired body having a porosity of 1.0% or less, and the first layer and the second layer are formed. The surface of the layer is a fired surface exposed unprocessed, and the arithmetic average roughness Ra of 10 points average at a measurement length of 4 mm is 0.1 μm or more and 0.5 μm or less, and the YAG fluorescent material exposed on the surface The average 20-point arithmetic mean roughness Ra1 of 0.2 and 0.5 nm or less of the particles and YAG-based material measured at 1 μm, and the Al ₂ O ₃ particles exposed on the surface of 20 at a measured length of 1 μm. When the point average arithmetic average roughness Ra2 was 0.3 nm or more and 0.7 nm or less, it was confirmed that the color unevenness of the emitted light was suppressed and the light emission efficiency was excellent.
Further, as in Examples 44 to 47, 49 to 50, 52, and 53, 20 particles of the YAG-based fluorescent material particles containing the activator in the first layer and the YAG-based material particles in the second layer were used. The average diameter d1 is not less than 0.5 μm and not more than 5 μm, and the 20 average diameters d2 of the Al ₂ O ₃ particles in each of the first and second layers are not less than 1 μm and not more than 10 μm, and the YAG in the first layer volume composition ratio of the system fluorescent material and the _Al 2 _{O 3} is, YAG-based fluorescent material is not more than 35 volume% 22 volume% or more, _Al 2 _{O 3} is within the range of less than 78 volume% 65 volume% or more, The volume composition ratio between the YAG-based material and Al ₂ O ₃ in the second layer is a range in which the YAG-based material is 22% by volume to 35% by volume and the Al ₂ O ₃ is 65% by volume to 78% by volume. Higher emission when in It was confirmed that the rate can be obtained.

DESCRIPTION OF SYMBOLS 1 Wavelength conversion baking body 2 Incident surface 3 Outgoing surface 4 Side surface 5 Side surface 11 Wavelength conversion baking body (wavelength conversion laminated composite)
12 First layer 13 Second layer 14 Intermediate layer 15 Light emitting device

Claims (6)

One main surface is a light incident surface, and the main surface opposite to the incident surface is a plate-like body that is a light emission surface,
The plate-like body is composed of a fired body having a porosity of 1.0% or less composed of fluorescent material particles and translucent material particles containing an activator,
At least the entrance surface and the exit surface are fired surfaces on which the fluorescent material particles and the translucent material particles are exposed unprocessed, and an arithmetic average roughness Ra of 10 points average at a measurement length of 4 mm is 0.1 μm or more. 0.5 μm or less,
Translucent material exposed on the surface of the fired surface when the arithmetic average roughness Ra1 of the average of 20 points at a measurement length of 1 μm of the fluorescent material particles exposed on the surface of the fired surface is 0.2 nm to 0.5 nm The arithmetic average roughness Ra2 of 20-point average at a particle measurement length of 1 μm is 0.3 nm or more and 0.7 nm or less,
The fluorescent material is a general formula A ₃ B ₅ O ₁₂ : Ce (A is at least one selected from Y, Gd, Tb, Yb and Lu, and B is selected from Al, Ga and Sc) And the translucent material contains Al ₂ O ₃ or Al ₂ O ₃ and one selected from Sc ₂ O ₃ and Ga ₂ O _3. A wavelength-converted fired body characterized by being a material obtained .   The 20 average diameter d1 of the fluorescent material particles is 0.5 μm or more and 5 μm or less, the 20 average diameter d2 of the translucent material particles is 1 μm or more and 10 μm or less, and the proportion of the fluorescent material particles is 22 2. The wavelength conversion fired body according to claim 1, wherein the proportion of the translucent material particles is in the range of 78% to 65% by volume.   The 20 average diameter d1 of the 20 fluorescent material particles is 0.1 times or more and 0.78 times or less of the 20 average diameter d2 of the light transmissive material particles. 2. The wavelength conversion fired body according to 2.   The arithmetic average roughness Ra2 of the average of 20 points at the measurement length of 1 μm of the translucent material particles exposed on the surface is the arithmetic average roughness of the average of 20 points at the measurement length of 1 μm of the fluorescent material particles exposed on the surface. The wavelength conversion fired body according to any one of claims 1 to 3, wherein the wavelength conversion fired body is 1.2 to 2.0 times Ra1. A first layer composed of an activator-containing YAG-based fluorescent material and Al ₂ O ₃ ;
An intermediate layer made of Al ₂ O ₃ laminated on the first layer, and particles having a diameter of 20 μm or more and 300 μm or less occupying 90% or more of the total number of particles;
A second layer made of Al ₂ O ₃ and a YAG-based material laminated on the intermediate layer and containing an activator of 10% or less of the activator content of the first layer;
In each of the layers, the Al ₂ O ₃ particles are connected to each other, and at the interface of each layer, the Al ₂ O ₃ particles are connected to each other.
The first layer, the intermediate layer, and the second layer are all made of a fired body having a porosity of 1.0% or less, and the surfaces of the first layer and the second layer are exposed without being processed. On the fired surface, the arithmetic average roughness Ra of 10 points average at a measurement length of 4 mm is 0.1 μm or more and 0.5 μm or less,
Particles of Al ₂ O ₃ exposed on the surface when the arithmetic average roughness Ra1 of 20 points average at a measurement length of 1 μm of the particles of the YAG fluorescent material exposed on the surface is 0.2 nm or more and 0.5 nm or less The arithmetic average roughness Ra2 of 20 points average at a measurement length of 1 μm is 0.3 nm or more and 0.7 nm or less,
The first YAG fluorescent material activator-containing in the layer _{is, (Y1-sGds) 3 (} Al 1-t Ga t) 5 O 12: Ce (0 ≦ s ≦ 0.33,0 ≦ t ≦ 0.2) A wavelength conversion fired body characterized in that: The average diameter d1 of 20 particles of the activator-containing YAG-based fluorescent material in the first layer and the particles of the YAG-based material in the second layer is 0.5 μm or more and 5 μm or less. 20 average diameters d2 of the Al ₂ O ₃ particles in each layer are 1 μm or more and 10 μm or less,
The proportion of the activator-containing YAG-based fluorescent material particles in the first layer and the YAG material particles in the second layer is 22% by volume or more and 35% by volume in each of the first and second layers. 6. The wavelength conversion fired body according to claim 5, wherein the proportion of the Al ₂ O ₃ particles is 78 volume% or more and 65 volume% or less in each of the first layer and the second layer.

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