WO2019031016A1 - Wavelength conversion member and light-emitting device - Google Patents

Abstract

The purpose of the present invention is to provide a wavelength conversion member having little risk of performance degradation due to temperature quenching when used for high-power applications and capable of producing great light intensity with less energy. Provided is a wavelength conversion member 10 that includes a base material 12 and a phosphor layer 14 provided on the base material 12 and converts light having a wavelength within a specific range to light having a different wavelength, wherein: the thickness of the phosphor layer 14 is less than or equal to 200 µm and less than or equal to a quarter of the thickness of the base material 12 in the stacking direction of the phosphor layer 14; the phosphor layer 14 is made up of a light-transmissive inorganic material and phosphor particles 16 bonded to the inorganic material; the material of the phosphor particle 16 is either YAG:Ce or LuAG:Ce; and the concentration of Ce in the phosphor particle 16 is between 0.03 at% and 0.60 at%, inclusive.

Description

Wavelength conversion member and light emitting device

The present invention relates to a wavelength conversion member and a light emitting device that convert light of a specific range of wavelength into light of another wavelength.

As a light emitting element, for example, one in which a wavelength conversion member in which phosphor particles are dispersed in a resin typified by epoxy, silicone or the like is disposed so as to be in contact with a blue LED element. Then, in recent years, applications using laser diodes (LDs) have been increasing in place of LEDs, which are high in energy efficiency and easy to be compatible with miniaturization and high output.

Since the laser locally irradiates high energy light, the resin irradiated intensively burns the irradiated portion. On the other hand, by using an inorganic binder instead of resin and applying a phosphor plate consisting only of an inorganic material, the problem of heat resistance in the case of using a high energy excitation source such as a laser is solved. (Patent Document 1).

Further, for the purpose of obtaining white light emission without variation, a YAG phosphor ceramic sintered body is disclosed in which the concentration of Ce as an activator is within a predetermined range (Patent Document 2).

JP, 2015-038960, A JP, 2010-024278, A

Patent Document 1 discloses that the heat resistance of a phosphor plate is improved by forming the phosphor plate only with an inorganic material. However, the phenomenon called temperature quenching still occurs in which the performance of the phosphor itself disappears due to heat generation and storage for the laser power.

Further, Patent Document 2 discloses a YAG phosphor ceramic sintered body obtained by mixing and firing material powders and then polishing. However, since the heat dissipation when using a high energy excitation source is not taken into consideration, heat may be stored depending on the use environment, and there is a possibility that the performance may be degraded due to temperature quenching.

The present invention has been made in view of such circumstances, and in high-power applications, it is difficult to cause performance deterioration due to temperature quenching, and a wavelength conversion member and a light emitting device capable of obtaining a large amount of light emission with little energy. Intended to provide.

(1) In order to achieve the above object, the wavelength conversion member of the present invention converts light of a specific range of wavelength comprising a base material and a phosphor layer provided on the base material into light of another wavelength The phosphor layer has a thickness of 200 μm or less and a quarter or less of the thickness of the base in the laminating direction of the phosphor layer, and the phosphor layer is translucent. The phosphor particles are formed of an inorganic material and phosphor particles bonded to the inorganic material, and the material of the phosphor particles is either YAG: Ce or LuAG: Ce, and the Ce concentration of the phosphor particles is 0. It is characterized by being .03 at% or more and 0.60 at% or less.

As described above, by using a phosphor with a low Ce concentration, it is possible to disperse the heat generation point generated by the phosphor, reduce the density of the heat generated at the time of fluorescence conversion, and enhance the heat dissipation. It is possible to prevent the temperature rise. As a result, even in the case of excitation by a laser having high energy, it is difficult to reach a temperature at which the light emission performance of the phosphor decreases, and high emission intensity can be maintained even at high power. Further, by providing the base having a thickness larger than that of the phosphor layer, the base functioning as a heat sink occupies a large weight ratio, so that the heat can be dissipated from the base, and the heat dissipation can be further enhanced. It is possible to suppress the performance deterioration due to the temperature quenching.

(2) Further, in the wavelength conversion member of the present invention, the thickness of the phosphor layer is 10 μm or more, and the Ce concentration of the phosphor particles is 0.12 at% or more. Thereby, since the thickness and Ce concentration of a fluorescent substance layer are not too small, the fall of luminous efficiency can be suppressed.

(3) Further, in the wavelength conversion member of the present invention, the base material is formed of sapphire. As described above, by using sapphire, which is a transparent material that can be expected to have good heat dissipation due to high thermal conductivity, as a base material, it is possible to maintain high emission intensity when using a laser or the like having high energy as excitation light. The wavelength conversion member of a type | mold can be comprised.

(4) Further, in the wavelength conversion member of the present invention, the base is made of aluminum. As described above, by using aluminum, which is a reflective material that can be expected to have good heat dissipation due to high thermal conductivity, as a base material, reflection using a laser having high energy or the like as excitation light can maintain high emission intensity. The wavelength conversion member of a type | mold can be comprised.

(5) Further, the light emitting device of the present invention is a light emitting device including a light source generating light source light of a wavelength within a specific range, which absorbs the light source light, converts it into light of another wavelength and emits light. And the wavelength conversion member according to any one of (1) to (4). Thus, it is possible to configure a light emitting device capable of maintaining high light emission intensity even with high power and suppressing a decrease in light emission efficiency.

According to the present invention, it is possible to configure a wavelength conversion member in which performance degradation due to temperature quenching is unlikely to occur in high power applications, and a large amount of light emission can be obtained with a small amount of energy.

It is a schematic diagram showing the wavelength conversion member of this invention. (A) is a schematic diagram showing the transmission type light-emitting device of this invention. (B) is a schematic diagram showing the reflection type light-emitting device of this invention. It is a flowchart which shows the manufacturing method of the wavelength conversion member of this invention. It is sectional drawing which shows the transmission type evaluation system for the light emission intensity test with respect to a wavelength conversion member. FIG. 16 is a graph showing emission intensity when the laser power density (laser input) is taken on the horizontal axis for reflective samples 1 to 5. FIG. FIG. 16 is a graph showing emission intensity when the laser power density (laser input) is taken on the horizontal axis for transmission type samples 6 to 10. FIG. It is a table showing each result of various conditions of a sample, peak time laser input, peak time luminescence intensity, and luminescence intensity (luminous efficiency) at 3 W.

Next, embodiments of the present invention will be described with reference to the drawings. In order to facilitate understanding of the description, the same reference numerals are given to the same components in the respective drawings, and the overlapping description will be omitted. In the configuration diagram, the size of each component is conceptually represented, and does not necessarily represent an actual dimensional ratio.

[Configuration of Wavelength Conversion Member] FIG. 1 is a schematic view showing a wavelength conversion member 10. In the wavelength conversion member 10, a phosphor layer 14 is formed on a base 12. The wavelength conversion member 10 absorbs light from the light source and excites the light to generate light of different wavelengths while transmitting or reflecting the light from the light source. For example, while transmitting or reflecting the blue light source light, the converted light converted by the phosphor layer 14 is emitted to combine the converted light and the light source light, or to use only the converted light, various colors Can be converted to

In the case of the transmission type, the material of the substrate 12 may be a light transmitting material such as sapphire or glass. From the viewpoint of light emission intensity, the portion through which light is transmitted is at least a material that hardly absorbs light from the light source. In addition, since high-energy light is irradiated to raise the temperature, it is preferable that the heat conductivity be high. Therefore, the transmissive substrate is preferably made of sapphire.

In the case of a reflective type, a metal such as aluminum, iron, copper or the like can be used as the material of the base 12. The reflective substrate can be made of a material that reflects light, but all of the substrate can be made of a material that reflects light, such as silver that reflects light to one side of the material that does not allow for light transmission or reflection of light. The material may be provided by plating or the like. From the viewpoint of light emission intensity, the portion through which light is transmitted is at least a material that hardly absorbs light from the light source. In addition, since high-energy light is irradiated to raise the temperature, it is preferable that the heat conductivity be high. Therefore, the reflective base is preferably made of aluminum.

The phosphor layer 14 is provided on the base 12 as a film, and is formed of the phosphor particles 16 and the bonding material 20 (light transmitting inorganic material). The binder 20 fixes the phosphor particles 16 to one another, and the phosphor particles 16 and the base 12. Thereby, since it joins with the base material 12 which functions as a thermal radiation material with respect to irradiation of the light of high energy density, it can thermally radiate efficiently and can suppress the temperature quenching of fluorescent substance. In addition, it is preferable that the above-mentioned fixations be chemical bonds in order to efficiently dissipate heat.

The thickness of the phosphor layer 14 is 200 μm or less and one-fourth or less of the thickness of the base in the stacking direction of the phosphor layer. Since the base material which functions as a heat sink occupies a large weight ratio by this, heat dissipation from the fluorescent substance layer 14 to the base 12 is performed more reliably, and the performance fall by temperature quenching can be suppressed. Moreover, it is preferable that the thickness of the fluorescent substance layer 14 is 10 micrometers or more. Thereby, since the thickness of the fluorescent substance layer 14 is not too small, the fall of luminous efficiency can be suppressed. The thickness of the phosphor layer 14 is preferably 100 μm or less.

The phosphor particles 16 are made of either an yttrium aluminum garnet phosphor (YAG: Ce) or a lutetium aluminum garnet phosphor (LuAG: Ce) to which cerium (Ce) is added as a luminescent center. Be done. At this time, the Ce concentration of the luminescent center is defined as follows. That is, although the composition formula of YAG is Y ₃ Al ₅ O ₁₂ , YAG in which a part of yttrium (Y) is replaced with Ce is represented as YAG: Ce, and the composition formula is generally (Y _{3 -X} Ce _X ) represented as Al ₅ O ₁₂ And the ratio of Ce with respect to the number of atoms of the whole composition formula is represented by a unit "at%." For example, since 0.1 / (3 + 5 + 12) × 100 = 0.5 when X = 0.1, this is defined as 0.5 at%.

LuAG is obtained by replacing all Y in YAG with lutetium (Lu), and the composition formula is Lu ₃ Al ₅ O ₁₂ . Therefore, the Ce concentration of LuAG: Ce is also defined in the same manner as above, and is represented by the unit "at%".

The Ce concentration of the phosphor particles 16 is not less than 0.03 at% and not more than 0.60 at%. As described above, by using a phosphor with a low Ce concentration, it is possible to disperse the heat generation point generated by the phosphor, reduce the density of the heat generated at the time of fluorescence conversion, and enhance the heat dissipation. It is possible to prevent the temperature rise. As a result, even in the case of excitation by a laser having high energy, it is difficult to reach a temperature at which the light emission performance of the phosphor decreases, and high emission intensity can be maintained even at high power. The Ce concentration of the phosphor particles 16 is preferably 0.12 at% or more. Thereby, since the Ce concentration is not too small, it is possible to suppress the decrease in the light emission efficiency.

The Ce concentration of the phosphor particles can be analyzed by ICP or XRF. In any of the methods, a fluorescent substance with a known Ce concentration is used as a calibration curve. The Ce concentration may be determined as an average value of a plurality of analysis values.

The phosphor particles 16 absorb source light (excitation light) and emit converted light. YAG: Ce absorbs source light (excitation light) and emits yellow converted light. LuAG: Ce absorbs source light (excitation light) and emits green converted light. For example, when the source light is blue or purple, the source light and the converted light can be combined to emit white radiation.

The average particle diameter of the phosphor particles 16 is 1 μm or more and 30 μm or less, and preferably 5 μm or more and 20 μm or less. Since it is 1 μm or more, the emission intensity of the converted light is increased, and as a result, the emission intensity of the wavelength conversion member 10 is increased. Further, since the thickness is 30 μm or less, the temperature of each phosphor particle 16 can be maintained low, and temperature quenching can be suppressed. In addition, in this specification, an average particle diameter is a median diameter (D50), or an average particle diameter in the particle | grains obtained by analysis of a SEM image. The average particle diameter which is median diameter (D50) can be measured using dry measurement or wet measurement of a laser diffraction / scattering type particle diameter distribution measuring apparatus. The average particle diameter of the particles obtained by the analysis of the SEM image was obtained by acquiring the SEM image of the cross section by, for example, 1000 times, for the cross section in the direction perpendicular to the plane direction of the phosphor layer 14 An image analysis such as binarization is performed on the SEM image, and the cross-sectional area of 100 or more particles recognized as phosphor particles 16 can be calculated from the image, and the average particle diameter can be determined from the cumulative distribution. The image used when calculating the cross-sectional area of 100 or more particles recognized as phosphor particles from the image is a phosphor so that the overall average particle diameter of the phosphor particles 16 contained in the phosphor layer 14 can be obtained. Cross sectional images (for example, three or more sheets) at a plurality of locations in the layer 14 are acquired.

The binder 20 is formed by hydrolysis or oxidation of an inorganic binder, and is made of a translucent inorganic material. The bonding material 20 is made of, for example, silica (SiO ₂ ) or aluminum phosphate. Since the bonding material 20 is made of an inorganic material, it does not deteriorate even when irradiated with light of high energy such as a laser diode. In addition, since the bonding material 20 has a light transmitting property, the light source light and the converted light can be transmitted. As the inorganic binder, ethyl silicate, an aqueous solution of aluminum phosphate or the like can be used.

In addition, when a light is vertically incident on a target material of 0.5 mm in the wavelength region of visible light (λ = 380 to 780 nm), the substance having translucency emits light emitted from the opposite side. It refers to a material whose flux has a characteristic that exceeds 80% of the incident light.

By combining the light source with the light source, the wavelength conversion member 10 can maintain a high emission intensity even with high power, and can configure a light emitting device capable of suppressing a decrease in light emission efficiency. In particular, the wavelength conversion member 10 is in a predetermined range where the Ce concentration of the phosphor particles 16 is low, and the phosphor layer 14 is thinner than the base 12 functioning as a heat sink, and the phosphor layer 14 is made of an inorganic material. A high power laser diode can be used as a light source, and a high power light emitting device can be configured.

[Configuration of Light-Emitting Device] FIGS. 2A and 2B are schematic views showing the transmissive and reflective light-emitting devices of the present invention, respectively. The transmission type light emitting device 30 includes a light source 50 and a transmission type wavelength conversion member 10. The reflective light emitting device 40 includes a light source 50 and a reflective wavelength conversion member 10. The light source 50 can use an LED, a laser diode, or the like that generates light source light of a specific range of wavelength. The light source 50 is preferably a laser diode because the wavelength conversion member 10 can maintain high emission intensity even at high power.

[Method of Manufacturing Wavelength Conversion Member] An example of a method of manufacturing a wavelength conversion member will be described. FIG. 3 is a flowchart showing a method of manufacturing a wavelength conversion member of the present invention. First, a printing paste is prepared. First, phosphor particles having a predetermined Ce concentration and an average particle diameter are prepared (step S1). The phosphor particles are either YAG: Ce or LuAG: Ce.

Next, the prepared phosphor particles are weighed, dispersed in a solvent, and mixed with an inorganic binder to prepare a printing paste (step S2). A ball mill etc. can be used for mixing. As the solvent, high boiling point solvents such as α-terpineol, butanol, isophorone and glycerin can be used.

The inorganic binder is preferably an organic silicate such as ethyl silicate. By using the organic silicate, the phosphor particles are dispersed throughout the printing paste, and a printing paste with an appropriate viscosity can be produced. For example, when ethyl silicate is used as the inorganic binder, the weight of ethyl silicate is 70 wt% to 100 wt%, preferably 80 wt% to 90 wt%, based on the weight of water and the catalyst. In addition, the inorganic binder may be reacted at normal temperature with a raw material containing at least one member selected from the group consisting of silicon oxide precursors, silicic acid compounds, silica, and amorphous silica to be converted to silicon oxides by hydrolysis or oxidation, or It may be obtained by heat treatment at a temperature of 500 ° C. or less. As the silicon oxide precursor, for example, those containing perhydropolysilazane, ethyl silicate and methyl silicate as main components can be mentioned.

After producing the printing paste, the printing paste is applied onto the substrate to form a paste layer (step S3). The application of the printing paste may be screen printing, spraying, drawing by a dispenser, or inkjet. The screen printing method is preferable because a thin paste layer can be stably formed. The thickness of the paste layer is preferably adjusted to be 10 μm or more and 200 μm or less after firing.

Then, the base material on which the paste layer is formed is fired using an air furnace to produce a phosphor layer (step S4). The firing temperature is preferably 150 ° C. or more and 500 ° C. or less, and the firing time is preferably 0.5 hours or more and 2.0 hours or less. Further, the temperature rising rate is preferably 50 ° C./h or more and 200 ° C./h or less. Moreover, you may provide a drying process before baking.

By such a manufacturing process, it is possible to easily manufacture a wavelength conversion member in which the phosphor particles are uniformly present in the entire phosphor layer. The obtained wavelength conversion member can maintain high emission intensity even with high power, and can suppress a decrease in emission efficiency.

[Example] (Method of preparing sample) Phosphor particles (YAG: Ce particles and LuAG: Ce particles) having an average particle diameter of 6 μm and a Ce concentration of 0.03 at% to 0.90 at% were prepared. These phosphor particles were weighed, and α-terpineol (solvent) was mixed to prepare a dispersion material, which was then mixed with ethyl silicate (inorganic binder) to prepare a printing paste.

Next, using a screen printing method, the printing paste was applied to a substrate (a sapphire substrate or an aluminum substrate silver-coated on aluminum) to a thickness of 8 to 220 μm after firing. After coating, the coating was dried at 100 ° C. for 20 minutes and then sealed with an inorganic binder. Finally, the temperature was raised to 350 ° C. at 150 ° C./h using an air furnace, and firing was performed for 30 minutes to complete the sample.

The Ce concentration of the above sample was determined using ICP as a calibration curve using a phosphor whose Ce concentration is known. For the film thickness (thickness) of the phosphor layer, an SEM cross-sectional photograph of each sample is taken at a magnification of 1000 times, and 10 perpendicular lines are drawn at equal intervals, and the top surface of the base material from the top surface of the phosphor layer The distance up to was measured, and the film thickness of the phosphor layer was calculated from the average length of 10 lines.

(Evaluation Method of Samples) A reflection type or a transmission type emission intensity test was conducted on each completed sample by excitation with a plurality of lasers with a maximum of 24 W input. The wavelength of the source light was adjusted to 445 nm, and the irradiation diameter was adjusted to 0.15 mm ² by a condensing lens. FIG. 4 is a cross-sectional view showing a transmission type evaluation system for luminescence intensity test on a wavelength conversion member. As shown in FIG. 4, the transmissive evaluation system 700 includes a light source 710, a planar convex lens 720, a biconvex lens 730, a band pass filter 735, and a power meter 740. Each element is arranged so that the transmitted light from the wavelength conversion member 10 can be collected and measured.

The band pass filter 735 is a filter that cuts light with a wavelength of 480 nm as a threshold value, and a filter that cuts the side with a large wavelength is used when measuring the transmitted source light (absorbed light). Moreover, when measuring the emitted light intensity of conversion light, the filter which cuts the small side of a wavelength is used. Thus, in order to separate the transmitted source light from the converted light, it is installed between the biconvex lens and the power meter.

In the system configured as described above, the light source light entering the plane convex lens 720 is focused to the focal point on the sample S of the wavelength conversion member. Then, the emitted light generated from the sample S is condensed by the biconvex lens 730, and the intensity of the light cut by the band pass filter 735 is measured by the power meter 740. This measured value is taken as the emission intensity of the converted light. By condensing the laser light with a lens and reducing the irradiation area, the energy density per unit area can be increased even with a low-power laser. This energy density is taken as the laser power density. In addition, the reflective evaluation system can be evaluated by the same system except that the condensed light source light and the converted light are reflected by the substrate of the sample.

FIGS. 5 and 6 are graphs showing emission intensities when the laser power density (laser input) is taken on the horizontal axis for the reflective samples 1 to 5 and the transmissive samples 6 to 10, respectively. The above-mentioned luminescence intensity test was carried out for each sample, and peak laser input, peak luminescence intensity and luminescence intensity at 3 W were calculated. The peak laser input is a laser input that maximizes the light emission intensity when the laser power density (laser input) is taken along the horizontal axis. The peak emission intensity was taken as the emission intensity for the peak laser input. In addition, the peak emission intensity and the emission intensity at 3 W are represented as relative values when the emission type of the wavelength conversion member of sample 1 is 100 for the reflection type and the transmission type of the wavelength conversion member for sample 6 is 100. FIG. 7 is a table showing the results of various conditions of the sample, peak laser input, peak emission intensity, and emission intensity (emission efficiency) at 3 W. The values of Samples 11 to 20 were also calculated in the same manner as described above.

As can be seen from the graphs in FIGS. 5 and 6, in a predetermined range where the laser power density is low, the emission intensity increases linearly with the increase of the laser power density for each sample having a different Ce concentration. I understand. Therefore, the slope of the graph in that range can be considered to correspond to the light emission efficiency. Therefore, the light emission intensity at 3 W when all the samples shown in the graph are all linear graphs was regarded as the light emission efficiency.

The peak laser input was represented by ○ in the table as a pass when the peak emission intensity was greater than 100, and the x was represented as a fail. The relative value of the light emission intensity (light emission efficiency) at 3 W is preferably 35 or more, and more preferably 40 or more. This is because if the luminous efficiency is low, the proportion of source light transmitted or reflected without being absorbed by the phosphor particles increases, so if this proportion becomes excessive, it is necessary to control the source light transmitted or reflected and emitted Because it comes out. Therefore, the thing of 40 or more was represented by (circle), and the thing less than 40 was represented by (triangle | delta).

Samples 1 to 5 are reflection type wavelength conversion members, using YAG: Ce particles as phosphor particles, changing the Ce concentration while keeping the thickness of the substrate and the thickness (film thickness) of the phosphor layer constant. Sample. Since sample 1 has a high Ce concentration, heat can not be dispersed efficiently in the phosphor layer, and temperature quenching was performed at a low input of 3 W. Therefore, high energy excitation sources can not be used. Since samples 2 to 4 have the Ce concentration in the appropriate range, the heat dispersability in the phosphor layer is improved, and the peak laser input and the peak emission intensity are improved. In addition, the relative value of the luminous efficiency was kept at 40 or more with respect to the sample 1 as the reflection type reference. In Sample 5, the peak laser input and the peak emission intensity improved because the Ce concentration was low, but the relative value of the emission efficiency was less than 40.

Samples 6 to 10 are transmission type wavelength conversion members, in which YAG: Ce particles are used as phosphor particles, the thickness of the substrate and the film thickness of the phosphor layer are made constant, and the Ce concentration is changed. is there. Since the sample 6 has a high Ce concentration, heat can not be dispersed efficiently in the phosphor layer, and the temperature was quenched by 3 W. Therefore, high energy excitation sources can not be used. Samples 7 to 9 had the Ce concentration in the appropriate range, so the heat dispersibility in the phosphor layer was improved, and the peak laser input and peak emission intensity were improved. Further, the relative value of the luminous efficiency was kept at 40 or more with respect to the sample 6 as the transmission type reference. Since the sample 10 had a low Ce concentration, the peak laser input and the peak emission intensity improved, but the relative value of the emission efficiency fell below 35. As a reason for the relative value of luminous efficiency to be lower in the transmission type sample 10 than in the reflection type sample 5, in the case of the reflection type, when the light source light which is not first absorbed by the phosphor particles is reflected back In some cases, it may be absorbed by phosphor particles.

Samples 11, 12 and 13, 14 are transmission type wavelength conversion members, respectively, using YAG: Ce particles as phosphor particles, keeping the thickness of the substrate and the concentration of Ce constant, and setting the film thickness of the phosphor layer It is a changed sample. Since the film thickness of the sample 11 was thin, the light emission efficiency decreased. This is considered to be because when the film thickness is too thin, phosphors contributing to light emission decrease. The sample 14 had a film thickness of one-fourth or more with respect to the thickness of the substrate, so the peak laser input decreased. This is thought to be because the ratio of the thickness of the substrate to the thickness of the phosphor layer was insufficient due to the phosphor layer becoming too thick, and the heat in the phosphor layer was not efficiently dissipated by the substrate Be

Samples 15 and 16 are reflection type wavelength conversion members, using YAG: Ce particles as phosphor particles, making the Ce concentration constant, and making the base material thicker than Samples 1 to 5; It is the sample to which the film thickness of the fluorescent substance layer was changed. In the sample 15, since the film thickness of the phosphor layer and the ratio of the thickness of the base material to the film thickness of the phosphor layer are within the appropriate range, all the results satisfied the reference. In the sample 16, the ratio of the thickness of the base material to the thickness of the phosphor layer was in the appropriate range, but the peak laser input and the peak emission intensity did not meet the criteria because the thickness of the phosphor layer was too thick. . This is because when the film thickness is too thick, heat exceeding the effect of heat dispersion in the phosphor layer due to the change of the Ce concentration is generated, the heat dissipation of the phosphor layer itself is reduced, and heat is generated in the phosphor layer It is thought that it is for the purpose of healing.

Samples 17 to 20 are reflection type wavelength conversion members, in which the concentration of the substrate and the thickness of the phosphor layer are made constant, and the Ce concentration is changed, using LuAG: Ce particles as the phosphor particles. is there. Even when using LuAG: Ce particles, as in the case of using YAG: Ce particles, heat dispersion in the phosphor layer is improved when the Ce concentration is in the proper range, and the peak laser input and peak The light emission intensity was improved. In addition, the relative value of the luminous efficiency was kept at 40 or more with respect to the sample 1 as the reflection type reference.

From the above results, it has been found that the wavelength conversion member of the present invention is less likely to cause performance deterioration due to temperature quenching in high power applications, and can obtain a large amount of light emission with less energy.

Reference Signs List 10 wavelength conversion member 12 base 14 phosphor layer 16 phosphor particle 20 bonding material 30 transmission type light emitting device 40 reflection type light emitting device 50 light source 700 evaluation system 710 light source 720 planar convex lens 730 biconvex lens 735 band pass filter 740 power meter S sample

Claims (5)

A wavelength conversion member for converting light of a specific range of wavelength into light of another wavelength, comprising a base material and a phosphor layer provided on the base material, comprising:

The thickness of the phosphor layer is 200 μm or less, and is 1⁄4 or less of the thickness of the base in the stacking direction of the phosphor layer,

The phosphor layer is formed of a translucent inorganic material and phosphor particles combined with the inorganic material.

The material of the phosphor particles is either YAG: Ce or LuAG: Ce,

The wavelength conversion member, wherein the Ce concentration of the phosphor particles is 0.03 at% or more and 0.60 at% or less.
The thickness of the phosphor layer is 10 μm or more.

The wavelength conversion member according to claim 1, wherein the Ce concentration of the phosphor particles is 0.12 at% or more.
The wavelength conversion member according to claim 1, wherein the base material is formed of sapphire.
The said base material is formed with aluminum, The wavelength conversion member of Claim 1 or Claim 2 characterized by the above-mentioned.
What is claimed is: 1. A light emitting device comprising a light source for generating light source light of a specific range of wavelength, comprising:

A light emitting device comprising: the wavelength conversion member according to any one of claims 1 to 4, which absorbs the light from the light source, converts the light into light of another wavelength, and emits the light.

Images