JP6499237B2 - Light wavelength conversion member and light emitting device - Google Patents

Description

  The present disclosure relates to a light wavelength conversion member and a light emitting device capable of converting the wavelength of light, such as those used in wavelength conversion devices, fluorescent materials, various types of illumination, video equipment, and the like.

  For example, in headlamps and various lighting devices, a device that obtains white by converting the wavelength of blue light of a light emitting diode (LED) or a semiconductor laser (LD: Laser Diode) with a phosphor is mainly used. It has become.

  As the phosphor, a resin system or a glass system is known, but in recent years, the output of the light source has been increased, and the phosphor has been required to have higher durability. Attention has been focused on ceramic phosphors (see Patent Documents 1 to 3).

As this ceramic phosphor, as represented by Y ₃ Al ₅ O ₁₂ : Ce (YAG: Ce), a phosphor having a garnet structure (A ₃ B ₅ O ₁₂ ) with Ce activated is known. ing.

JP 2014-132804 A JP-A-2015-34120 JP-A-2015-149394

By the way, the above-described conventional technology has the following problems, and improvements have been demanded.
Specifically, in the technique described in Patent Document 1, CeAl ₁₁ O ₁₈ is dispersed in the structure in order to prevent color unevenness accompanying Ce volatilization during firing. However, CeAl ₁₁ O ₁₈ which is the third component absorbs light, which causes a decrease in emission intensity and illuminance. For this reason, it is necessary to deal with such a case that the thickness of the phosphor is extremely reduced. However, the thinning has another problem that the durability of the phosphor as a structure is impaired.

  Moreover, in the technique described in Patent Document 2, the content of rare earth elements that can be luminescent center ions is 1 to 50 mol%. However, when the content of the luminescent center ion is large, the emission intensity and the luminous flux may decrease due to concentration quenching. Therefore, if it is in this range, the fluorescence characteristics and the illuminance are significantly lowered.

Furthermore, in the technique described in Patent Document 3, in order to suppress reflection of excitation light at the interface between YAG and Al ₂ O ₃ , a structure in which YAG that does not activate Ce surrounds YAG that can be a light-emitting component. Is taking. However, this structure makes it difficult for heat generated by the fluorescent component YAG to escape and causes temperature quenching.

That is, with the above-described technique, it is not easy to realize a light wavelength conversion member that has high illuminance and fluorescence intensity and can suppress color unevenness.
The present disclosure has been made in view of the above problems, and an object thereof is to provide a light wavelength conversion member and a light-emitting device that have high illuminance and fluorescence intensity and can suppress color unevenness.

  (1) A first aspect of the present disclosure includes a ceramic sintered body having a fluorescent phase mainly composed of fluorescent crystal particles and a translucent phase mainly composed of translucent crystal particles. The present invention relates to a light wavelength conversion member.

In this light wavelength conversion member, the crystal particles in the fluorescent phase have a composition represented by the chemical formula A ₃ B ₅ O ₁₂ : Ce, and each of the A element and the B element is at least one selected from the following element group It is composed of the elements.

A: Lanthanoid excluding Sc, Y, and Ce B: Al, Ga
Further, in this light wavelength conversion member, the area ratio of the light transmitting phase to the fluorescent phase (that is, the area of the light transmitting phase / the area of the fluorescent phase) a in the cross section of the light wavelength converting member is 0.3 <a <34. In addition, the interface length y of the fluorescent phase within the range of the unit area 500 μm ^{2 in} the cross section is 300 μm <y <1050 μm.

In the first aspect, as a basic configuration, the ceramic sintered body has a garnet structure represented by A ₃ B ₅ O ₁₂ : Ce, which is composed of at least one element selected from the element group. Have.

With this composition, blue light can be efficiently converted into visible light.
In particular, in the first aspect, the area ratio of the light transmitting phase to the fluorescent phase (that is, the area of the light transmitting phase / the area of the fluorescent phase) a in the cross section of the light wavelength conversion member is 0.3 <a <34. In addition, since the interface length y of the fluorescent phase within the range of the unit area of 500 μm ^{2 in} the cross section is 300 μm <y <1050 μm, the light is applied to the light wavelength conversion member as will be apparent from Examples and the like described later. When irradiated, high illuminance and fluorescence intensity can be obtained, and color unevenness is reduced.

  Here, when the interface length y of the fluorescent phase is less than 300 μm, that is, the mass of the fluorescent phase becomes large in a predetermined region (specifically, per specified unit area), or the content of the fluorescent phase is small. Then, since diffusion at the interface between the fluorescent phase and the light transmitting phase is reduced, the transmittance is improved, and the illuminance and fluorescence intensity are improved, but color unevenness occurs.

  On the other hand, when the interface length y of the fluorescent phase exceeds 1050 μm, that is, when the mass of the fluorescent phase in a predetermined region becomes small, the diffusion at the interface increases, so the transmittance decreases and the color unevenness decreases. , Illuminance and fluorescence intensity will decrease.

  On the other hand, when the area ratio a is less than 0.3, the fluorescent phase is insufficient, so that sufficient translucency is not exhibited, and the illuminance and fluorescence intensity are reduced. On the other hand, when the area ratio a exceeds 34, the fluorescent component is insufficient, and thus sufficient light emission is not exhibited.

The light wavelength conversion member of the first aspect has excellent performance with respect to heat resistance and durability.
(2) In the second aspect of the present disclosure, the ratio of the average particle diameter r1 of the crystal particles in the light transmitting phase to the average particle diameter r2 of the crystal particles in the fluorescent phase (ie, r1 / r2) x is 1.1 < x <2.1, the average particle diameter r1 of the crystal particles in the light transmitting phase is in the range of 0.2 μm to 6 μm, and the average particle diameter r2 of the crystal particles in the fluorescent phase is in the range of 0.1 μm to 4 μm. There may be.

When the ratio x (that is, the particle size ratio x) is less than 1.1, the transmittance is lowered and the diffusion of blue light is increased, so that the color unevenness is reduced, but the illuminance and the fluorescence intensity are reduced. .
On the other hand, when the particle size ratio x exceeds 2.1, the transmittance is improved and the illuminance and fluorescence intensity are improved, but color unevenness occurs.

Therefore, the range of the particle size ratio x is preferable.
Further, it is high when the average particle diameter r1 of the crystal particles in the light transmitting phase is in the range of 0.2 μm to 6 μm and the average particle diameter r2 of the crystal particles in the fluorescent phase is in the range of 0.1 μm to 4 μm. A ceramic phosphor having little color unevenness while having fluorescence intensity and illuminance can be obtained.

  Here, when the average particle diameter r1 of the crystal particles in the light transmitting phase is less than 0.2 μm and the average particle diameter r2 of the crystal particles in the fluorescent phase is less than 0.1 μm, the diffusion of blue light and yellow light is performed. However, although the color unevenness is reduced, the transmittance of blue light and yellow light is reduced, and the fluorescence intensity and illuminance are also reduced.

  On the other hand, when the average particle diameter r1 of the transparent phase crystal particles is larger than 6 μm and the average particle diameter r2 of the fluorescent phase crystal particles is larger than 4 μm, the transmittance is increased and the fluorescence intensity and the illuminance are improved. However, the color unevenness becomes large.

(3) In the third aspect of the present disclosure, the crystal particles of the light transmitting phase may have a composition of Al ₂ O ₃ .
Here, a suitable example of the composition of the crystal particles of the light transmitting phase is shown.

(4) In the fourth aspect of the present disclosure, the compound represented by the chemical formula A ₃ B ₅ O ₁₂ : Ce may be in a range of 3 vol% to 70 vol% of the entire ceramic sintered body.
Ceramic sintered body in _A 3 in _B 5 _O 12: ratio of Ce is, if it is the whole range of 3vol% ~70vol%, it is possible to obtain a small ceramic sintered body color unevenness while having a high illuminance .

  Here, if the said ratio is less than 3 vol%, since the fluorescence component is insufficient, it does not show sufficient light emission. On the other hand, when the ratio exceeds 70 vol%, the light-transmitting phase is insufficient, so that sufficient light-transmitting properties are not exhibited, and illuminance and fluorescence intensity are reduced.

(5) In the fifth aspect of the present disclosure, the Ce concentration in the compound represented by the chemical formula A ₃ B ₅ O ₁₂ : Ce is in the range of 0.1 mol% to 1.0 mol% with respect to the element A of the compound. May be.

When the Ce concentration of the compound represented by A ₃ B ₅ O ₁₂ : Ce in the ceramic sintered body is in the range of 0.1 mol% to 1.0 mol% with respect to the A element, high illuminance and fluorescence intensity are obtained. A ceramic sintered body with little color unevenness can be obtained.

Here, if the said ratio is less than 0.1 mol%, since there are few luminescent center ions and a fluorescent component is insufficient, sufficient light emission cannot be obtained. On the other hand, when the ratio exceeds 1.0 mol%, the concentration of the luminescent center ion is high, concentration quenching occurs, and the fluorescence intensity and illuminance decrease.
(6) 6th aspect of this indication is a light-emitting device provided with the optical wavelength conversion member in any one of 1st-5th aspect.

The light (that is, fluorescence) whose wavelength is converted by the light emitting device of the sixth aspect (specifically, the light wavelength conversion member) has high fluorescence intensity. Moreover, it has high color uniformity.
In addition, as a light emitting element of a light-emitting device, well-known elements, such as LED and LD, can be used, for example.

<Each configuration of the present invention will be described below>
-"Fluorescent phase" is a phase mainly composed of crystal particles having fluorescence, and "Translucent phase" is a crystal particle having translucency, specifically, a crystal particle having a composition different from that of crystal particles in a fluorescent phase. It is a phase mainly composed of.

  “Subject” indicates that the largest amount (ie, volume) exists in the light wavelength conversion member. For example, the fluorescent phase may contain 50% by volume or more (preferably 90% by volume or more) of crystal particles having fluorescence. Further, for example, the light transmitting phase may contain 50 vol% or more (preferably 90 vol% or more) of crystal particles having translucency.

  The “light wavelength conversion member” is a ceramic sintered body having the above-described configuration, and each crystal particle and its grain boundary may contain inevitable impurities. In this ceramic sintered body, the light-transmitting phase and the light-transmitting phase (therefore, fluorescent crystal particles and translucent crystal particles) are 50% by volume or more (preferably 90% by volume or more) of the ceramic sintered body. ) May be included.

- _"A 3 _B 5 _O 12: Ce" _means, Ce part of the element A in A ₃ B _{5 O 12} has indicated that the solid solution substitution, by having such a structure The compound exhibits fluorescence characteristics.

The “interface length” is the total length of the outer circumferences of the portions constituting one or a plurality of fluorescent phases in a predetermined region of the cross section of the light wavelength conversion member, specifically, in a unit area of 500 μm ² . For example, when there are a plurality of fluorescent phases separated from the surroundings in a predetermined region, the total interface length of the fluorescent phases is obtained.

It is sectional drawing which shows the cross section which fractured | ruptured the light-emitting device provided with the light wavelength conversion member of embodiment in the thickness direction. It is explanatory drawing which shows the manufacturing process of the optical wavelength conversion member of embodiment. It is the schematic diagram of the SEM image of the cross section of the optical wavelength conversion member of embodiment, and the schematic diagram of the SEM image which does not perform an etching process in detail. It is the schematic diagram of the SEM image of the cross section of the optical wavelength conversion member of embodiment, and the schematic diagram of the SEM image which carried out the etching process in detail. It is explanatory drawing which shows the measuring method of a color nonuniformity.

Next, embodiments of the light wavelength conversion member and the light emitting device of the present disclosure will be described.
[1. Embodiment]
[1-1. Light emitting device]
First, the light wavelength conversion member and the light emitting device of this embodiment will be described.

  As shown in FIG. 1, a light emitting device 1 of the present embodiment includes a box-shaped ceramic package (container) 3 such as alumina, and a light emitting element 5 such as an LD disposed inside the container 3. And a plate-like light wavelength conversion member 9 disposed so as to cover the opening 7 of the container 3.

  In the light emitting device 1, the light emitted from the light emitting element 5 is transmitted through the light wavelength conversion member 9 having translucency, and a part of the light is wavelength-converted inside the light wavelength conversion member 9 to emit light. To do. That is, the light wavelength conversion member 9 emits fluorescence having a wavelength different from the wavelength of the light emitted from the light emitting element 5.

For example, blue light emitted from the LD is wavelength-converted by the light wavelength conversion member 9, so that white light as a whole is emitted from the light wavelength conversion member 9 to the outside (for example, upward in FIG. 1).
[1-2. Optical wavelength conversion member]
Next, the light wavelength conversion member 9 will be described.

  The light wavelength conversion member 9 of the present embodiment has a fluorescent phase mainly composed of fluorescent crystal particles (that is, fluorescent phase particles) and a translucent light mainly composed of translucent crystal particles (that is, fluorescent phase particles). And a ceramic sintered body having a phase.

In this light wavelength conversion member 9, the fluorescent phase particles have a composition represented by the chemical formula A ₃ B ₅ O ₁₂ : Ce, and each of the A element and the B element is at least one selected from the following element group It is composed of the elements.

A: Lanthanoid excluding Sc, Y, and Ce B: Al, Ga
In the chemical formula A ₃ B ₅ O ₁₂ : Ce, A and B represent each element (however, a different element) constituting the substance represented by the chemical formula A ₃ B ₅ O ₁₂ : Ce, O is oxygen, Ce is cerium.

In the light wavelength conversion member 9, the area ratio (that is, the area of the light transmission phase / the area of the fluorescence phase) a in the cross section of the light wavelength conversion member 9 is 0.3 <a <34. And the interface length y in the predetermined region of the fluorescent phase within the range of the unit area of 500 μm ^{2 in} the cross section is 300 μm <y <1050 μm.

The predetermined region is a unit area having a size of 500 μm ² , and the interface length y is the total of the interface lengths indicating the circumference of each fluorescent phase in the unit area.
Further, the ratio of the average particle diameter r1 of the light transmitting phase particles to the average particle diameter r2 of the fluorescent phase particles (ie, r1 / r2) x is 1.1 <x <2.1, The average particle diameter r1 of the crystal particles is in the range of 0.2 μm to 6 μm, and the average particle diameter r2 of the crystal particles in the fluorescent phase is in the range of 0.1 μm to 4 μm.

Furthermore, the optical wavelength conversion member 9, the formula _A 3 _B 5 _O 12: a compound represented by Ce is in the range of 3vol% ~70vol% of the total ceramic sintered body.
The Ce concentration in the compound represented by the chemical formula A ₃ B ₅ O ₁₂ : Ce is in the range of 0.1 mol% to 1.0 mol% with respect to the A element of the compound.

The light transmitting phase particles have, for example, a composition of Al ₂ O ₃ .
[1-2. Manufacturing method of optical wavelength conversion member]
Here, a schematic procedure for manufacturing the light wavelength conversion member 9 will be briefly described with reference to FIG.

First, the powder material of the light wavelength conversion member 9 which is a ceramic sintered body was weighed (that is, prepared) so as to satisfy the configuration of the embodiment.
Next, an organic solvent and a dispersant were added to the prepared powder material, and pulverized and mixed with a ball mill to prepare a slurry.

Next, the obtained slurry was dried and granulated.
Next, the obtained granulated powder was press-molded.
Next, the press-molded body was fired at a predetermined temperature for a predetermined time to obtain a ceramic sintered body.

In addition to the above-described method for producing a ceramic sintered body by press molding, a ceramic sintered body may be obtained by firing a sheet molded body obtained by sheet forming a slurry.
[1-3. effect]
Next, the effect of this embodiment will be described.

(1) In the present embodiment, as a basic configuration, the ceramic sintered body is represented by A ₃ B ₅ O ₁₂ : Ce composed of at least one element selected from the element group. It has a structure. With this composition, blue light can be efficiently converted into visible light.

In particular, in the present embodiment, the area ratio of the light transmitting phase to the fluorescent phase (that is, the area of the light transmitting phase / the area of the fluorescent phase) a in the cross section of the light wavelength conversion member 9 is 0.3 <a <34. And the interface length y of the fluorescent phase in the range of the unit area of 500 μm ^{2 in} the cross section is 300 μm <y <1050 μm. Therefore, when the light wavelength conversion member 9 is irradiated with light from the light emitting element 5, for example, there is an effect that high illuminance and fluorescence intensity can be obtained and color unevenness is small.

(2) In this embodiment, the ratio of the average particle diameter r1 of the light transmitting phase particles to the average particle diameter r2 of the fluorescent phase particles (ie, r1 / r2) x is 1.1 <x <2.1. The average particle diameter r1 of the crystal particles in the light transmitting phase is in the range of 0.2 to 6 μm, and the average particle diameter r2 of the crystal particles in the fluorescent phase is in the range of 0.1 to 4 μm.

With this configuration, higher illuminance and fluorescence intensity can be obtained, and color unevenness can be reduced.
(3) In the present embodiment, the compound represented by the chemical formula A ₃ B ₅ O ₁₂ : Ce is in the range of 3 vol% to 70 vol% of the entire ceramic sintered body.

With this configuration, higher illuminance and fluorescence intensity can be obtained, and color unevenness can be reduced.
(4) In the present embodiment, the Ce concentration in the compound represented by the chemical formula A ₃ B ₅ O ₁₂ : Ce is in the range of 0.1 mol% to 1.0 mol% with respect to the element A of the compound.

With this configuration, higher illuminance and fluorescence intensity can be obtained, and color unevenness can be reduced.
(5) Light (that is, fluorescence) whose wavelength is converted by the light emitting device 1 of this embodiment, specifically, the light wavelength conversion member 9, has high fluorescence intensity. In addition, there is little color variation and high color uniformity.
[2. Example]
Next, specific examples of the embodiment will be described.

Here, each sample of the ceramic sintered bodies No. 1 to 30 described in Table 1 below, that is, each sample of the light wavelength conversion member of Examples 1 to 5 was prepared.
Of the samples, Nos. 3 to 7, 11 to 30 are samples within the scope of the present disclosure, and Nos. 1, 2, and 8 to 10 are samples outside the scope of the present disclosure (comparative example). .
[2-1. Sample evaluation method]
First, each evaluation method performed on each sample will be described.

<Relative density>
The relative density of the ceramic sintered body of each sample was calculated by measuring the density by the Archimedes method and converting the measured density to the relative density.

<Open porosity>
The open porosity of the ceramic sintered body of each sample was measured by the method defined in JIS R1634.

<Area ratio>
The ceramic sintered body of each sample was broken, the fractured surface was mirror-polished, and the polished surface was observed with a scanning electron microscope (SEM) to obtain a 5000-fold SEM image. A schematic diagram of an example of the SEM image is shown in FIG. 3, where a bright portion close to white is a fluorescent phase, and a dark portion close to black is a translucent phase.

Then, in the SEM image, the area ST of the light transmitting phase and the area SK of the fluorescent phase were measured in the region of 500 μm ² , respectively. Then, an area ratio a between the area ST of the light transmitting phase and the area SK of the fluorescent phase was obtained by calculation of ST / SK.

The area was obtained by processing the SEM image with image analysis software (for example, Winloof). In addition, if the 500 μm ² region is a 5000 times SEM image, the area ratio a may be obtained by converting to 500 μm ² after measurement in a specific visual field range. The same applies to the interface length described later, and may be converted per 500 μm ² .

<Average crystal grain size>
The ceramic sintered body of each sample was fractured, and the fractured surface was mirror-polished, followed by thermal etching at 1350 ° C. The etched surface was observed with an SEM, and images of 2500 times (that is, SEM images) were obtained at arbitrary five positions in the ceramic sintered body. A schematic diagram of an example of the SEM image is shown in FIG. 4, where the bright part is the fluorescent phase particle and the dark part is the light transmitting phase particle.

  Then, within the 20 μm square in each SEM image at each position, five arbitrary lines are drawn, and the average crystal grain size (that is, the average grain size) of the fluorescent phase particles and the transparent phase particles is determined by the intercept method. Asked. That is, the average particle diameter r2 of the fluorescent phase particles and the average particle diameter r1 of the light transmitting phase particles were determined in the entire five regions.

<Particle size ratio>
Furthermore, the particle size ratio x was calculated from the average particle size r2 of the obtained fluorescent phase particles and the average particle size r1 of the light transmitting phase particles using the following formula (1).

Particle size ratio x = transparent phase particle average particle size r1 / fluorescent phase particle average particle size r2 (1)
<Interface length>
Using the image analysis software (for example, Winloof) for the 5000 times SEM image used when determining the area ratio, the interface length for each fluorescent phase in each region at any five positions Asked. That is, the interface length in units of a single fluorescent phase was determined. Moreover, in the area | region with two or more fluorescence phases, the interface length of each fluorescence phase was totaled. That is, the interface length of all fluorescent phases in each region was obtained, and the total value (that is, the total interface length for each region) was obtained for each region.

Here, each area | region in five positions is each a magnitude | size of 500 micrometers ² , The total interface length in each area | region calculated | required in the area | region of five positions was calculated | required, and the average value was made into interface length y.

  FIG. 3 shows an example of the interface length, that is, the interface length of the fluorescent phase in units of fluorescent phase. In FIG. 3, the length of the white circular line surrounding one fluorescent phase (that is, one light gray bright portion) is the interface length in units of fluorescent phase.

<Illuminance>
The illuminance was measured with a luminometer. Specifically, blue LD light having a wavelength of 465 nm is condensed with a lens to a width of 0.5 mm for each sample processed to a 13 mm square × thickness 0.2 mm, and this is irradiated and transmitted from the opposite surface. The illuminance of the incoming light was measured with a spectral irradiance meter (CL-500A manufactured by Konica Minolta).

The illuminance was evaluated as a relative value (%) when the strength of the YAG: Ce single crystal was 100.
<Color unevenness>
Color unevenness (that is, color variation) was evaluated by measuring chromaticity variation with an illuminometer.

  Specifically, blue LD light having a wavelength of 465 nm is condensed with a lens to a width of 0.5 mm for each sample processed to a 13 mm square × thickness 0.2 mm, and this is irradiated and transmitted from the opposite surface. The chromaticity of the incoming light was measured with a spectral irradiance meter (CL-500A manufactured by Konica Minolta).

  As shown in FIG. 5, with respect to the surface of each sample (ie, the sample surface), the irradiation is performed by dividing the 9 mm square central portion into 9 regions at intervals of 3 mm, and the chromaticity (X direction) of each region. Variation (Δx) was evaluated. The variation (Δx) indicates the maximum value of deviation in the chromaticity direction, and preferably Δx <0.03.

  The chromaticity is an international display method established in 1931 by the International Commission on Illumination (CIE) and is a chromaticity represented by the CIE-XYZ color system. That is, the chromaticity is represented by an xy chromaticity diagram (so-called CIE chromaticity diagram) in which the three primary colors on the color are digitized and the colors are expressed in the xy coordinate space.

<Fluorescence intensity>
Each sample processed to 13 mm square x 0.2 mm thickness is irradiated with blue LD light having a wavelength of 465 nm by condensing it to a width of 0.5 mm with a lens, and the transmitted light is condensed with the lens, and the power sensor Was used to measure the emission intensity (ie, fluorescence intensity). The power density irradiated at this time was set to 40 W / mm ² .

The fluorescence intensity was evaluated as a relative value (%) when the intensity of the YAG: Ce single crystal was 100.
[2-2. Sample manufacturing method and evaluation results]
Next, a manufacturing method of each sample and an evaluation result of each sample will be described.

<Example 1>
Samples of ceramic sintered bodies No. 1 to 9 (that is, light wavelength conversion members) were produced under the conditions shown in Table 1 below.

Specifically, according to the ceramic sintered body of each sample, as shown in Table 1 below, Al ₂ O ₃ (average particle size 0.2 μm) and Y ₂ O ₃ (average particle size 1.2 μm), Each powder material of Gd ₂ O ₃ (average particle size 1.5 μm) and CeO ₂ (average particle size 1.5 μm) was weighed.

At this time, the amount of A ₃ B ₅ O ₁₂ : Ce was fixed at 30 vol% of the entire ceramic sintered body. The Ce concentration was fixed at 0.3 mol% with respect to the A element.
These powders were put into a ball mill together with ethanol and pulverized and mixed for 4 to 48 hours. The obtained slurry was dried and granulated, and the obtained granulated powder was press-molded. The obtained molded body was fired in an air atmosphere. At this time, firing was performed at a firing temperature of 1500 to 1800 ° C. and a holding time of 2 to 10 hours.

Specifically, in Sample Nos. 1 and 2, the pulverization time was longer than 30 hours, the firing temperature was 1500 ° C., and the holding time was 2 to 5 hours.
In sample Nos. 3 to 7, the pulverization time was 16 hours, the firing temperature was 1500 ° C. to 1750 ° C., and the holding time was 10 hours.

In Sample Nos. 8 and 9, the grinding time was 16 hours and 4 hours, the firing temperature was the same 1800 ° C., and the holding time was the same 10 hours.
In addition, each sample of Example 1 can be obtained by changing a grinding | pulverization time and baking conditions in the range of the said conditions. For example, by increasing the pulverization time, the particle size of the crystal particles can be reduced. Further, by increasing the firing temperature, crystal grains can be grown and the particle size can be increased. Therefore, these are considered to affect the interface length.

Next, the ceramic sintered body of each sample obtained by this manufacturing method was evaluated by the above-described evaluation method. The results are shown in Table 1 below.
As is clear from Table 1, the samples No. 3 to 7 in which the area ratio a is in the range of 0.3 <a <34 and the interface length y of the fluorescent phase is in the range of 300 μm <y <1050 μm. Had high fluorescence intensity and illuminance, and had little color unevenness, and good results were obtained.

  On the other hand, the samples No. 1 and No. 2 in which the interface length y exceeded 1050 μm had decreased transmittance, and decreased fluorescence intensity and illuminance. Further, in the samples No. 8 and 9 having an interface length y of less than 300 μm, the transmission of blue light became very large, and thus the color unevenness increased.

Although not shown in Table 1, the relative density of each sample was 99% or more. The same applies to the samples of other Examples 2 to 4.
<Example 2>
Under the conditions shown in Table 1 below, samples of ceramic sintered bodies No. 10 to 19 were prepared.

The method for preparing the sample of Example 2 is basically the same as that of Example 1.
However, the grinding time was fixed at 16 hours, the firing temperature was 1600 ° C., and the holding time was 10 hours. Further, the amount of A ₃ B ₅ O ₁₂ : Ce was adjusted to 1 vol% to 80 vol% of the whole.

The ceramic sintered body of each sample obtained by this manufacturing method was evaluated by the above-described evaluation method. The results are shown in Table 1 below.
As can be seen from Table 1, the samples No. 11 to 18 with A ₃ B ₅ O ₁₂ : Ce content of 3 vol% to 70 vol% have high emission intensity, small color unevenness, and good results. It was.

On the other hand, the sample No. 10 having a small amount of A ₃ B ₅ O ₁₂ : Ce of 1 vol% had low fluorescence intensity due to insufficient fluorescence. Further, the No. 19 sample having a large amount of A ₃ B ₅ O ₁₂ : Ce of 80 vol% showed a significant increase in temperature due to a decrease in thermal conductivity, and the emission intensity decreased due to temperature quenching.

<Example 3>
Under the conditions shown in Table 1 below, samples of ceramic sintered bodies of Nos. 20 to 26 were produced.
The method for producing the sample of Example 3 is basically the same as that of Example 1.

However, the grinding time and firing conditions were the same as in Example 2. Moreover, the amount of A ₃ B ₅ O ₁₂ : Ce was fixed at 30 vol% of the whole, and the amount of Ce was set to 0.05 vol% to 2.0 vol%.
The ceramic sintered body of each sample obtained by this manufacturing method was evaluated by the above-described evaluation method. The results are shown in Table 1 below.

As is clear from Table 1, the samples Nos. 21 to 25 having the Ce amount of 0.1 vol% to 1 vol% had high emission intensity and illuminance, small color unevenness, and good results were obtained.
On the other hand, the sample No. 20 having a Ce content of less than 0.1 mol% has a low fluorescence intensity due to insufficient fluorescence because of a small amount of luminescent center ions. Further, in the sample No. 26 in which the amount of Ce was more than 1 mol%, concentration quenching occurred due to an excessive amount of Ce, and the fluorescence intensity was lowered.

<Example 4>
Under the conditions shown in Table 1 below, samples of ceramic sintered bodies No. 27 to 30 were produced.
The method for producing the sample of Example 3 is basically the same as that of Example 1.

However, not only Y ₂ O ₃ powder at the time of blending, but also Lu ₂ O ₃ (average particle size 1.3 μm), Yb ₂ O ₃ (average particle size 1.5 μm), Ga ₂ O ₃ (average particle size 1.3 μm) The compounding ratio was changed so that a predetermined A ₃ B ₅ O ₁₂ : Ce could be synthesized using one or more of each of the above powders. The pulverization time and firing conditions were the same as in Example 2.

The ceramic sintered body of each sample obtained by this manufacturing method was evaluated by the above-described evaluation method. The results are shown in Table 1 below.
As is clear from Table 1, all of the ceramic sintered bodies of Nos. 27 to 30 had good results in terms of illuminance, fluorescence intensity, and color unevenness.

[4. Other Embodiments]
It is needless to say that the present disclosure is not limited to the above-described embodiment and can be implemented in various modes without departing from the present invention.

  (1) For example, in the above-described example, the sample was produced by atmospheric firing, but in addition, a sample having equivalent performance by hot press firing, vacuum firing, reducing atmosphere firing, HIP, or a firing method combining these. Can be produced.

(2) Examples of uses of the light wavelength conversion member and the light emitting device include various uses such as phosphors, light wavelength conversion devices, headlamps, illumination, and optical devices such as projectors.
(3) The light-emitting element used in the light-emitting device is not particularly limited, and various elements such as well-known LEDs and LDs can be employed.

  (4) In addition, the function which one component in the said embodiment has may be shared by a some component, or the function which a some component has may be exhibited by one component. Moreover, you may abbreviate | omit a part of structure of the said embodiment. In addition, at least a part of the configuration of the above embodiment may be added to or replaced with the configuration of another embodiment. In addition, all the aspects included in the technical idea specified from the wording described in the claims are embodiments of the present disclosure.

DESCRIPTION OF SYMBOLS 1 ... Light-emitting device 5 ... Light emitting element 9 ... Light wavelength conversion member

Claims (6)

A fluorescent phase mainly composed of fluorescent crystal particles;
A translucent phase mainly composed of crystal grains having translucency;
In a light wavelength conversion member composed of a ceramic sintered body having
The fluorescent phase crystal particles have a composition represented by the chemical formula A ₃ B ₅ O ₁₂ : Ce, and the A element and the B element are each composed of at least one element selected from the following element group: Has been
A: Lanthanoid excluding Sc, Y, and Ce B: Al, Ga
Area ratio of the transparent phase and the fluorescent phases in the cross section of the optical wavelength conversion member (i.e., area / area of the fluorescent phase Toruhikarisho) a is a 0.3 <a <34, and, the The interface length y of the fluorescent phase within a unit area of 500 μm ^{2 in} the cross section is 300 μm <y <1050 μm.
Light wavelength conversion member. The ratio (ie, r1 / r2) x of the average particle diameter r1 of the crystal particles of the light transmitting phase and the average particle diameter r2 of the crystal particles of the fluorescent phase is 1.1 <x <2.1, The average particle diameter r1 of the crystal particles of the light transmitting phase is in the range of 0.2 μm to 6 μm, and the average particle diameter r2 of the crystal particles of the fluorescent phase is in the range of 0.1 μm to 4 μm.
The wavelength conversion member according to claim 1. The crystal particles of the light transmitting phase have a composition of Al ₂ O ₃ ,
The light wavelength conversion member according to claim 1 or 2. The compound represented by the chemical formula A ₃ B ₅ O ₁₂ : Ce is in the range of 3 vol% to 70 vol% of the entire ceramic sintered body.
The light wavelength conversion member of any one of Claims 1-3. The Ce concentration in the compound represented by the chemical formula A ₃ B ₅ O ₁₂ : Ce is in the range of 0.1 mol% to 1.0 mol% with respect to the element A of the compound.
The optical wavelength conversion member of any one of Claims 1-4. The optical wavelength conversion member according to any one of claims 1 to 5 is provided.
Light emitting device.