TW201921042A - 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 [mu]m 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 wavelengths into light of other wavelengths.

As a light-emitting element, for example, a wavelength conversion member in which phosphor particles are dispersed in a resin typified by epoxy, silicone, or the like so as to be in contact with a blue LED element is known. Moreover, in recent years, the use of laser diodes (LDs), which have high energy efficiency and are easy to cope with miniaturization and high output, has been increasing instead of LEDs.

Since the laser system irradiates high-energy light locally, the resin irradiated by the laser light concentratedly will burn the irradiated part. On the other hand, by using an inorganic adhesive instead of a resin and applying a phosphor plate composed of only an inorganic material, the problem of heat resistance when using an excitation source with a high energy such as laser is solved (Patent Document 1).

Also disclosed is a YAG phosphor ceramic sintered body in which the Ce concentration as an activator is set in a predetermined range in order to obtain white light emission without deviation (Patent Document 2).

Prior art literature Patent literature

Patent Document 1 Japanese Patent Application Publication No. 2015-038960

Patent Document 2 Japanese Patent Application Publication No. 2010-024278

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

Further, Patent Document 2 discloses a YAG phosphor ceramic sintered body obtained by mixing and firing material powders and then grinding them. However, since the exothermicity when using a high-energy excitation source is not taken into consideration, there is a possibility that performance degradation due to temperature quenching due to heat accumulation due to the use environment may occur.

The present invention has been developed in view of such circumstances, and an object thereof is to provide a wavelength conversion member and a light-emitting device that are less likely to cause performance degradation due to temperature quenching in high-power applications and can obtain a larger amount of light with less energy. .

(1) In order to achieve the above object, the wavelength conversion member of the present invention includes a base material and a phosphor layer provided on the base material, and converts light of a specific range of wavelengths into light of other wavelengths. The characteristic of the wavelength conversion member is : The thickness of the phosphor layer is 200 μm or less and is less than 4 minutes 1 of the thickness of the substrate in the lamination direction of the phosphor layer; the phosphor layer is composed of a translucent inorganic material and a combination of the inorganic material and the inorganic material; It is formed of phosphor particles, and the material of the phosphor particles is either YAG: Ce or LuAG: Ce, and the Ce concentration of the phosphor particles is 0.03 at% or more and 0.60 at% or less.

As described above, by using a phosphor having a small Ce concentration, it is possible to disperse the generation points of the heat generated by the phosphor, reduce the density of the heat generated during the fluorescence conversion and improve the heat release property, and prevent the entire phosphor layer. The temperature rises. As a result, it is difficult to reach a temperature at which the luminous performance of the phosphor decreases even during excitation by a laser or the like having a high energy, and high luminous intensity can be maintained even at high power. In addition, since the base material having a thickness larger than that of the phosphor layer has a large weight ratio as a base material functioning as a heat radiation plate, it is possible to perform heat radiation from the base material, which can further improve heat radiation properties, and Inhibits performance degradation due to temperature quenching.

(2) 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. Accordingly, since the thickness of the phosphor layer and the Ce concentration are not too small, it is possible to suppress a decrease in light emission efficiency.

(3) In the wavelength conversion member of the present invention, the substrate is made of sapphire. In this way, it is possible to construct a transmission-type wavelength conversion member that uses a sapphire of a transparent material that can be expected to have good heat release properties with a high thermal conductivity as a base material, thereby using a laser or the like having high energy as the excitation light , Can maintain high light emission intensity.

(4) In the wavelength conversion member of the present invention, the base material is made of aluminum. In this way, it is possible to construct a reflection-type wavelength conversion member that uses aluminum as a base material of a reflective material that can expect good heat release properties with high thermal conductivity, thereby using a laser or the like having high energy as the excitation light. , Can maintain high light emission intensity.

(5) The light-emitting device of the present invention is a light source provided with light source light having a specific range of wavelengths, and is characterized by including a wavelength conversion member according to any one of (1) to (4) above to absorb light from the light source The light is converted into light of another wavelength to emit light. This makes it possible to construct a light-emitting device that can maintain a high light-emitting intensity even at a high power and can suppress a decrease in light-emitting efficiency.

According to the present invention, in a high-power application, it is possible to constitute a wavelength conversion member that is hard to cause degradation in performance due to temperature quenching and can obtain a large amount of light emission with less energy.

10‧‧‧ Wavelength Conversion Component

12‧‧‧ substrate

14‧‧‧ phosphor layer

16‧‧‧ phosphor particles

20‧‧‧Combination

30‧‧‧ transmissive light-emitting device

40‧‧‧Reflective lighting device

50‧‧‧ light source

700‧‧‧ evaluation system

710‧‧‧light source

720‧‧‧ Plano Convex Lens

730‧‧‧Biconvex lens

735‧‧‧Band Pass Filter

740‧‧‧Power Meter

S‧‧‧ sample

FIG. 1 is a schematic diagram showing a wavelength conversion member of the present invention.

FIG. 2 (a) is a schematic view showing a transmissive light-emitting device of the present invention; FIG. 2 (b) is a schematic view showing a reflective light-emitting device of the present invention.

FIG. 3 is a flowchart showing a method of manufacturing a wavelength conversion member according to the present invention.

FIG. 4 is a cross-sectional view showing a transmission-type evaluation system for a light emission intensity test of a wavelength conversion member.

FIG. 5 is a graph showing the luminous intensity when the laser power density (laser input) is used as the horizontal axis for reflective samples 1 to 5. FIG.

FIG. 6 is a graph showing the luminous intensity when the laser power density (laser input) is used as the horizontal axis for the transmissive samples 6 to 10.

FIG. 7 is a table showing the results of various conditions of the sample, the laser input at the peak, the light emission intensity at the peak, and the light emission intensity (light emission efficiency) at 3W.

A form for implementing the invention

Next, an embodiment of the present invention will be described with reference to the drawings. In order to facilitate understanding of the description, the same constituent elements are denoted by the same reference numerals in each drawing, and repeated description is omitted. In addition, the size of each component is shown conceptually in a configuration diagram, and does not necessarily show an actual dimensional ratio.

    [Configuration of wavelength conversion member]    

FIG. 1 is a schematic diagram showing a wavelength conversion member 10. The wavelength conversion member 10 has a phosphor layer 14 formed on a base material 12. The wavelength conversion member 10 absorbs and excites the light source light while transmitting or reflecting the light source light emitted from the light source to generate light having different wavelengths. For example, while transmitting or reflecting the light source light of blue light, the converted light converted by the phosphor layer 14 is radiated, and the converted light and the light source light are combined or only converted light can be converted into light of various colors.

When the material of the base material 12 is a transmissive type, a material having translucency such as sapphire or glass can be used. From a viewpoint of light emission intensity, a portion where light is transmitted is a material that is at least difficult to absorb light from a light source. In addition, since high-temperature light is radiated, the temperature becomes high, so it is preferable to have a high thermal conductivity. Therefore, the transmissive substrate is preferably formed of sapphire.

When the material of the base material 12 is reflective, metals such as aluminum, iron, and copper can be used. For reflective substrates, all substrates can be made of materials that reflect light, or they can be set to reflect on the side of a material that has translucency or a material that does not consider light reflection, such as plating. Light of silver and other materials. From a viewpoint of light emission intensity, a portion where light is transmitted is a material that is at least difficult to absorb light from a light source. In addition, since high-temperature light is irradiated, the temperature becomes high, so it is preferable to have a high thermal conductivity. Therefore, the reflective substrate is preferably formed of aluminum.

The phosphor layer 14 is formed on a substrate 12 as a film, and is formed by phosphor particles 16 and a bonding material 20 (transparent inorganic material). The bonding material 20 fixes the phosphor particles 16 to each other, and the phosphor particles 16 and the base material 12. Accordingly, since irradiation with light having a high energy density is bonded to the base material 12 which functions as a heat-radiating material, it is possible to efficiently radiate heat and suppress temperature quenching of the phosphor. The above-mentioned respective fixations are preferred because they are chemically bonded to efficiently release heat.

The thickness of the phosphor layer 14 is 200 μm or less and is not more than 1/4 of the thickness of the substrate in the lamination direction of the phosphor layer. Thereby, since the base material functioning as a heat radiation plate occupies a large weight ratio, the heat radiation from the phosphor layer 14 to the base material 12 can be performed more reliably, and the performance degradation due to temperature quenching can be suppressed. The thickness of the phosphor layer 14 is preferably 10 μm or more. Thereby, since the thickness of the phosphor layer 14 is not excessively small, it is possible to suppress a decrease in light emission efficiency. The thickness of the phosphor layer 14 is preferably 100 μm or less.

The phosphor particles 16 are made of yttrium, aluminum, garnet-based phosphors (YAG: Ce) or thorium, aluminum, and garnet-based phosphors (LuAG: Ce) with cerium (Ce) as a light emitting center. Constituted by one. At this time, the Ce concentration of the emission center is defined as follows. That is, the composition formula of YAG is Y ₃ Al ₅ O ₁₂ , and YAG obtained by replacing a part of yttrium (Y) with Ce is represented as YAG: Ce, and its composition formula is generally (Y _3-X Ce _X ) Al ₅ O _{12 is} represented. The ratio of Ce to the total number of atoms in the composition formula is expressed in the unit "at%". For example, when X = 0.1, it is 0.1 / (3 + 5 + 12) × 100 = 0.5, which is defined as 0.5at%.

LuAG uses Y (Lu) to replace all Y in YAG, 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 expressed in the unit "at%".

The Ce concentration of the phosphor particles 16 is 0.03 at% or more and 0.60 at% or less. In this way, by using a phosphor with a small Ce concentration, the generation points of the heat generated by the phosphor can be dispersed, the density of the heat generated during fluorescence conversion can be reduced, and the exothermicity can be improved, and the phosphor layer can be prevented The overall temperature rises. As a result, it is difficult to reach a temperature at which the luminous performance of the phosphor is reduced during excitation by a laser or the like having a high energy, and a high luminous intensity can be maintained even at a high power. The Ce concentration of the phosphor particles 16 is preferably 0.12 at% or more. Thereby, since the Ce concentration does not become too small, it is possible to suppress a decrease in light emission efficiency.

The Ce concentration of the phosphor particles can be analyzed by ICP or XRF. In either method, Ce concentration is performed by using a known phosphor as a calibration curve. The Ce concentration can also be obtained by averaging the analysis values several times.

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

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. The reason is that since it is 1 μm or more, the light emission intensity of the converted light is increased, and the light emission intensity of the wavelength conversion member 10 is also increased. Moreover, since it is 30 micrometers 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 means a median diameter (D50), or the average particle diameter of the particle | grains obtained by analysis of an SEM image. It is the average particle diameter of the median diameter (D50), and it can be measured by a dry measurement or a wet measurement using a laser diffraction / scattering type particle size distribution measuring device. The average particle diameter of the particles obtained by the analysis of the SEM image can be obtained from a cross-section perpendicular to the plane direction of the phosphor layer 14, for example, by obtaining a SEM image of the cross-section at a magnification of 1000 times. In image analysis such as binarization, the cross-sectional area of 100 or more particles identified as phosphor particles 16 is calculated from the image, and the average particle diameter is obtained from the cumulative distribution. The image used when calculating the cross-sectional area of 100 or more particles identified as phosphor particles from the image is obtained so that the average particle diameter of the entire phosphor particles 16 contained in the phosphor layer 14 is obtained. A plurality of cross-sectional images (for example, three or more) of the phosphor layer 14.

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

In addition, the so-called light-transmitting substance means that for a 0.5-mm target substance, when the light is vertically incident in the wavelength region of visible light (λ = 380 to 780 nm), the radiation beam with light passing through from the opposite side exceeds 80% of incident light.

The wavelength conversion member 10 can be combined with a light source to constitute a light-emitting device that can maintain a high light-emitting intensity even at a high power and can suppress a decrease in light-emitting efficiency. In particular, the wavelength conversion member 10 has a low Ce concentration in the phosphor particles 16, the phosphor layer 14 is thinner than the base material 12 functioning as a heat radiation plate, and the phosphor layer 14 is made of an inorganic material. A high-output laser diode can be used as a light source, and a high-output light-emitting device can be constructed.

    [Configuration of Light-Emitting Device]    

(A) and (b) of FIG. 2 are schematic diagrams respectively showing a transmissive type and a reflective type light emitting device of the present invention. The transmissive light-emitting device 30 includes a light source 50 and a transmissive 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 may be an LED, a laser diode, or the like that generates light source light having a specific range of wavelengths. Since the wavelength conversion member 10 can maintain a high light emission intensity even at a high power, the light source 50 is preferably a laser diode.

    [Manufacturing method of wavelength conversion member]    

An example of a method for manufacturing a wavelength conversion member will be described. FIG. 3 is a flowchart showing a method of manufacturing a wavelength conversion member according to the present invention. First, a printing paste is produced. 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). For mixing, a grinder or the like can be used. As the solvent, high-boiling 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 an organosilicate to disperse phosphor particles throughout the printing paste, a printing paste having an appropriate viscosity can be produced. For example, when using ethyl silicate as an inorganic binder, the mass of ethyl silicate is 70% by weight to 100% by weight relative to the mass of water and catalyst, preferably 80% by weight to 90% by weight. quality. In addition, inorganic binders can also be included in the group consisting of silicon oxide precursors, silicon oxide compounds, silicon dioxide, and amorphous silica that are converted to silicon oxide by hydrolysis or oxidation. It is obtained by reacting at least one of the raw materials at room temperature or by performing heat treatment at a temperature of 500 ° C or lower. Examples of the silicon oxide precursor include those containing perhydropolysilazane, ethyl silicate, and methyl silicate as main components.

After the printing paste is prepared, the printing paste is applied on the substrate to form a paste layer (step S3). The printing paste can be applied by a screen printing method, a spray method, a drawing method using a dispenser, and a spray method. It is preferable to use a screen printing method because a thin paste layer can be formed stably. The thickness of the paste layer is preferably adjusted to 10 μm or more and 200 μm or less after firing.

The base material on which the fired paste layer is formed is fired using an atmospheric furnace to produce a phosphor layer (step S4). The firing temperature is preferably 150 ° C to 500 ° C, and the firing time is preferably 0.5 hours to 2.0 hours. The temperature increase rate is preferably 50 ° C / h or more and 200 ° C / h or less. A drying step may be provided before firing.

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

    [Example] (Method for making sample)    

Fluorescent 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, α-terpineol (solvent) was mixed to make a dispersion material, and ethyl silicate (inorganic binder) was mixed to make a printing paste.

Next, a screen printing method is used to apply a printing paste to a substrate (a sapphire substrate or an aluminum substrate coated with silver on aluminum) so that the thickness becomes 8 to 220 μm after firing. After coating, it was dried at 100 ° C for 20 minutes, and then sealed with an inorganic adhesive. Finally, the temperature was increased to 350 ° C. at 150 ° C./h using an atmospheric furnace, and the sample was fired for 30 minutes.

The Ce concentration of the above-mentioned sample was performed using ICP and using a phosphor having a known Ce concentration as a calibration curve. In addition, the film thickness (thickness) of the phosphor layer was taken at 1000 times the SEM cross-section photograph of each sample, and 10 vertical lines were drawn at equal intervals to measure the distance from the top surface of the phosphor layer to the top surface of the substrate. For the distance, the film thickness of the phosphor layer was calculated from the average length of 10 lines.

    (Evaluation method of sample)    

For each completed sample, a reflection-type or transmission-type light emission intensity test was performed with excitation generated by a plurality of lasers with an input of a maximum of 24 W. The wavelength of the light source light was 445 nm, and the irradiation diameter was adjusted to 0.15 mm ² by a condenser lens. FIG. 4 is a cross-sectional view showing a transmission-type evaluation system for performing a light emission intensity test on a wavelength conversion member. As shown in FIG. 4, the transmission-type evaluation system 700 includes a light source 710, a plano-convex lens 720, a lenticular 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 is collected and measured.

The band-pass filter 735 is a filter that cuts light using a wavelength of 480 nm as a threshold. When measuring the transmitted light source light (absorbed light), a filter that cuts off the larger wavelength is used. When measuring the light emission intensity of the converted light, a filter that cuts off the wavelength is used. In this way, in order to separate the transmitted light source light from the converted light, the band-pass filter 735 is provided between the lenticular lens and the power meter.

In the system configured in this manner, the light source light entering the plano-convex lens 720 is focused toward the focal point of the sample S of the wavelength conversion member. Then, the lenticular lens 730 for the emitted light generated from the sample S is condensed, and the intensity of the light blocked by the band-pass filter 735 is measured with the power meter 740 for the condensed light. This measured value is set to the light emission intensity of the converted light. By condensing the laser light with a lens and converging the irradiation area, even a low-output laser can increase the energy density per unit area. Let this energy density be the laser power density. In addition, regarding the reflection-type evaluation system, the same system can be used for evaluation except that the collected light source light and converted light are reflected by the substrate of the sample.

FIG. 5 and FIG. 6 are graphs showing luminous intensities when the laser power density (laser input) is used as the horizontal axis for the reflective samples 1 to 5 and the transmissive samples 6 to 10, respectively. The above-mentioned light emission intensity test was performed on each sample, and the laser input at the peak, the light emission intensity at the peak, and the light emission intensity at 3 W were calculated. The laser input at the peak is a laser input where the laser power density (laser input) becomes the maximum when the luminous intensity is the horizontal axis. The light emission intensity at the peak is the light emission intensity with respect to the laser input at the peak. In addition, regarding the light emission intensity at the peak and the light emission intensity at 3 W, the reflection type is represented by a relative value when the light emission intensity of the wavelength conversion member of Sample 1 is 100, and the transmission type is the light emission intensity of the wavelength conversion member of Sample 6. Relative value when set to 100. In addition, FIG. 7 is a table showing the results of various conditions of the sample, the laser input at the peak, the light emission intensity at the peak, and the light emission intensity (light emission efficiency) at 3W. For samples 11 to 20, each value was calculated in the same manner as described above.

As can be seen from looking at the graphs of FIG. 5 and FIG. 6, it is learned that for samples with different Ce concentrations, in a predetermined range where the laser power density is low, the luminous intensity increases linearly with respect to the increase in laser power density. Therefore, the inclination of the graph in this range can be considered to correspond to the luminous efficiency. Therefore, the light emission intensity at 3 W of the graph in which all the samples shown in the graph are linear is regarded as the light emission efficiency.

The laser input at the peak is greater than 3W, and the relative value of the luminous intensity at the peak is greater than 100 as a pass, which is indicated by ○ in the table, and those that fail are indicated by ×. The light emission intensity (light emission efficiency) at 3 W is preferably a relative value of 35 or more, and more preferably 40 or more. The reason is that when the luminous efficiency is small, the proportion of the light source light that is transmitted or reflected without being absorbed by the phosphor particles will increase. Therefore, once the ratio becomes excessive, it is necessary to control the transmitted or reflected light source light to be emitted. Therefore, those with 40 or more are represented by ○, and those with less than 40 are represented by △.

Samples 1 to 5 are reflection-type wavelength conversion members. YAG: Ce particles are used as phosphor particles, and the thickness of the substrate and the thickness (film thickness) of the phosphor layer are fixed to change the Ce concentration. . Since sample 1 has a high Ce concentration, thermal dispersion in the phosphor layer cannot be performed efficiently, and the temperature is quenched at a low input of 3W. Therefore, a high-energy excitation source cannot be used. Samples 2 to 4 have a Ce concentration in an appropriate range, so the heat dispersion in the phosphor layer is improved, and the laser input at the peak and the luminous intensity at the peak are improved. In addition, the relative value of the luminous efficiency is also maintained at 40 or more with respect to the reference sample 1 which is a reflection type reference. Sample 5 has a low Ce concentration, so although the laser input at the peak and the luminous intensity at the peak are improved, the relative value of the luminous efficiency is lower than 40.

Samples 6 to 10 are transmission-type wavelength conversion members, and YAG: Ce particles are used as phosphor particles. The thickness of the base material and the film thickness of the phosphor layer are fixed to change the Ce concentration. Since sample 6 has a high Ce concentration, thermal dispersion in the phosphor layer cannot be performed efficiently, and temperature quenching occurs at 3W. Therefore, high-energy excitation sources cannot be used. Samples 7 to 9 have a Ce concentration in an appropriate range, so the heat dispersion in the phosphor layer is improved, and the laser input at the peak and the luminous intensity at the peak are improved. In addition, the relative value of the luminous efficiency was also maintained at 40 or more with respect to the sample 6 which is a reference of the transmission type. Since the sample 10 has a low Ce concentration, although the laser input at the peak and the luminous intensity at the peak are increased, the relative value of the luminous efficiency is lower than 35. The reason why the relative value of the luminous efficiency of the transmissive sample 10 becomes lower than that of the reflective sample 5 is considered to be because, in the case of the reflective type, when the light source light that was not originally absorbed by the phosphor particles is reflected back, Absorbed by phosphor particles.

Samples 11, 12, 13, and 14 are transmission-type wavelength conversion members, and YAG: Ce particles are used as the phosphor particles. The thickness of the substrate and the Ce concentration are fixed to change the film thickness of the phosphor layer. Of the sample. Since the sample 11 has a thin film thickness, the luminous efficiency is reduced. This is because when the film thickness is too thin, the phosphors that contribute to light emission are reduced. Since the sample thickness of the sample 14 is at least one-fourth of the thickness of the base material, the laser input at the peak is reduced. This is considered to be because the phosphor layer became too thick, so the ratio of the thickness of the substrate to the thickness of the phosphor layer was insufficient, and the heat in the phosphor layer did not efficiently radiate heat from the substrate.

Samples 15 and 16 are reflective wavelength conversion members, and YAG: Ce particles are used as the phosphor particles. The Ce concentration is constant, and the thickness of the substrate is 1 to 5 thicker than that of the sample. Then, the film of the phosphor layer is formed. Thick change sample. Regarding Sample 15, 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 in a proper range, so the results all meet the criteria. Regarding Sample 16, although the ratio of the thickness of the base material to the film thickness of the phosphor layer was in an appropriate range, the film thickness of the phosphor layer was too thick, so the laser input at the peak and the light emission intensity at the peak did not meet the reference. This is considered to be because when the film thickness is too thick, heat exceeding the effect of thermal dispersion in the phosphor layer due to a change in Ce concentration is generated, the exothermic property of the phosphor layer itself is reduced, and the phosphor layer is filled with heat.

Samples 17 to 20 are reflective wavelength conversion members, and LuAG: Ce particles are used as the phosphor particles. The thickness of the substrate and the film thickness of the phosphor layer are set to be constant, so that the Ce concentration is changed. Even when using LuAG: Ce particles, the same as when using YAG: Ce particles, when the Ce concentration is in a proper range, the heat dispersion in the phosphor layer will be improved, and the laser input at the peak and the light emission at the peak will be improved strength. In addition, the relative value of the luminous efficiency was also maintained at 40 or more with respect to the sample 1 which is a reference for reflection.

From the above results, it is understood that the wavelength conversion member of the present invention is less likely to suffer from performance degradation due to temperature quenching in high-power applications, and can obtain a large amount of light with a small amount of energy.

Claims (5)

    A wavelength conversion member comprising a base material and a phosphor layer provided on the base material and converting light of a specific range of wavelengths into light of other wavelengths, characterized in that the thickness of the phosphor layer is 200 μm or less and is the aforementioned The thickness of the base material in the lamination direction of the phosphor layer is less than 4 minutes 1; the phosphor layer is formed of a translucent inorganic material and phosphor particles combined with the inorganic material. The material is either YAG: Ce or LuAG: Ce, and the Ce concentration of the phosphor particles is 0.03 at% or more and 0.60 at% or less.         The wavelength conversion member according to claim 1, wherein 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.         The wavelength conversion member according to claim 1 or 2, wherein the aforementioned substrate is formed of sapphire.         The wavelength conversion member according to claim 1 or 2, wherein the aforementioned substrate is formed of aluminum.         A light-emitting device is provided with a light source that generates light source light of a specific range of wavelengths, and is characterized by having a wavelength conversion member according to any one of claims 1 to 4 to absorb and convert the light from the light source into light of other wavelengths While glowing.