JP6853140B2 - Wavelength conversion member and light emitting device - Google Patents

Description

The present invention relates to a wavelength conversion member and a light emitting device that convert light having a specific range of wavelengths into light having 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 or silicone so as to come into contact with a blue LED element is known. In recent years, there have been an increasing number of applications in which a laser diode (LD) is used instead of an LED, which has high energy efficiency and is easy to cope with miniaturization and high output.

Since the laser locally irradiates high-energy light, the resin irradiated with the laser light intensively burns the irradiated portion. On the other hand, by using an inorganic binder instead of resin and applying a phosphor plate made of only an inorganic material, the problem of heat resistance when 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 having a Ce concentration as an activator within a predetermined range is disclosed (Patent Document 2).

Japanese Unexamined Patent Publication No. 2015-08960 Japanese Unexamined Patent Publication No. 2010-024278

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

Further, Patent Document 2 discloses a YAG phosphor ceramic sintered body obtained by mixing and firing material powder and then polishing. However, since heat dissipation when a high-energy excitation source is used is not taken into consideration, heat storage may occur depending on the usage environment and performance may deteriorate due to temperature quenching.

The present invention has been made in view of such circumstances, and is a wavelength conversion member and a light emitting device that are less likely to cause performance deterioration due to temperature quenching in high power applications and can obtain a large amount of light emission with a small amount of energy. The purpose is to provide.

(1) In order to achieve the above object, the wavelength conversion member of the present invention converts light having a specific range of wavelengths including a base material and a phosphor layer provided on the base material into light having another wavelength. The thickness of the phosphor layer is 200 μm or less and one-fourth or less of the thickness of the base material in the stacking direction of the phosphor layer, and the phosphor layer is translucent. It is 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.

In this way, by using a phosphor having a low Ce concentration, it is possible to disperse the heat generation points generated by the phosphor, reduce the heat density generated during fluorescence conversion, and improve the heat dissipation property of the entire phosphor layer. It is possible to prevent the temperature from rising. As a result, even when excited by a laser or the like having high energy, it becomes difficult to reach a temperature at which the emission performance of the phosphor deteriorates, and high emission intensity can be maintained even at high power. Further, by providing a base material having a thickness larger than that of the phosphor layer, the base material functioning as a heat radiating plate occupies a large weight ratio, so that heat can be dissipated from the base material, further improving heat dissipation. It is possible to suppress the deterioration of performance due to 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. As a result, the thickness of the phosphor layer and the Ce concentration are not too small, so that a decrease in luminous efficiency can be suppressed.

(3) Further, in the wavelength conversion member of the present invention, the base material is made of sapphire. In this way, by using sapphire, which is a transparent material that can be expected to have good heat dissipation due to its high thermal conductivity, as the base material, transmission that can maintain high emission intensity when a laser or the like having high energy is used for excitation light. A type of wavelength conversion member can be constructed.

(4) Further, in the wavelength conversion member of the present invention, the base material is made of aluminum. In this way, by using aluminum, which is a reflective material that can be expected to have good heat dissipation due to its high thermal conductivity, as the base material, reflection that can maintain high emission intensity when a laser or the like having high energy is used for excitation light. A type of wavelength conversion member can be constructed.

(5) Further, the light emitting device of the present invention is a light emitting device including a light source that generates light source light having a wavelength in a specific range, and absorbs the light source light, converts it into light having another wavelength, and emits light. It is characterized by including the wavelength conversion member according to any one of 1) to (4). As a result, it is possible to configure a light emitting device capable of maintaining high light emission intensity even at high power and suppressing a decrease in light emission efficiency.

According to the present invention, it is possible to configure a wavelength conversion member capable of obtaining a large amount of light emission with a small amount of energy without causing performance deterioration due to temperature quenching in high power applications.

It is a schematic diagram which shows the wavelength conversion member of this invention. (A) is a schematic diagram showing the transmission type light emitting device of the present invention. (B) is a schematic diagram showing the reflection type light emitting device of the present 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 emission intensity test for a wavelength conversion member. It is a graph which shows the light emission intensity when the laser power density (laser input) is taken on the horizontal axis about the reflection type samples 1-5. It is a graph which shows the light emission intensity when the laser power density (laser input) is taken on the horizontal axis about the transmission type samples 6-10. It is a table showing various conditions of a sample, and the results of each of the peak laser input, the peak emission intensity, and the emission intensity at 3W (luminous efficiency).

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 reference number is assigned to the same component in each drawing, and duplicate description is omitted. In the configuration diagram, the size of each component is conceptually represented, and does not necessarily represent the actual dimensional ratio.

[Structure of wavelength conversion member]
FIG. 1 is a schematic view showing a wavelength conversion member 10. In the wavelength conversion member 10, the phosphor layer 14 is formed on the base material 12. The wavelength conversion member 10 transmits or reflects the light source light emitted from the light source, absorbs and excites the light source light, and generates light having a different wavelength. For example, while transmitting or reflecting the light source of blue light, the converted light converted by the phosphor layer 14 is emitted, and the converted light and the light source are combined, or only the converted light is used, and various colors are used. Can be converted to light.

When the material of the base material 12 is a transmissive type, a translucent material such as sapphire or glass can be used. From the viewpoint of light emission intensity, at least the portion through which light is transmitted is made of a material that does not easily absorb light from the light source. Further, since high energy light is irradiated and the temperature rises, it is preferable that the heat conductivity is high. Therefore, the transmissive substrate is preferably formed of sapphire.

When the material of the base material 12 is a reflective type, a metal such as aluminum, iron, or copper can be used. Reflective substrates can be made entirely of light-reflecting material, such as silver, which reflects light on one side of a translucent material or a material that does not consider light reflection. The material may be provided by plating or the like. From the viewpoint of light emission intensity, at least the portion through which light is transmitted is made of a material that does not easily absorb light from the light source. Further, since high energy light is irradiated and the temperature rises, it is preferable that the heat conductivity is high. Therefore, the reflective base material is preferably made of aluminum.

The phosphor layer 14 is provided as a film on the base material 12, and is formed of the phosphor particles 16 and the binder 20 (translucent inorganic material). The binder 20 fixes the phosphor particles 16 to each other, the phosphor particles 16 and the base material 12. As a result, the base material 12 that functions as a heat radiating material is bonded to the irradiation of light having a high energy density, so that heat can be efficiently radiated and the temperature quenching of the phosphor can be suppressed. Further, it is preferable that each of the above fixations is a chemical bond 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 material in the stacking direction of the phosphor layer. As a result, since the base material that functions as the heat radiating plate occupies a large weight ratio, heat is more reliably dissipated from the phosphor layer 14 to the base material 12, and performance deterioration due to temperature quenching can be suppressed. The thickness of the phosphor layer 14 is preferably 10 μm or more. As a result, since the thickness of the phosphor layer 14 is not too small, it is possible to suppress a decrease in luminous efficiency. The thickness of the phosphor layer 14 is preferably 100 μm or less.

The phosphor particles 16 are composed of either an yttrium-aluminum-garnet-based phosphor (YAG: Ce) or a lutetium-aluminum-garnet-based phosphor (LuAG: Ce) to which cerium (Ce) is added as a light emitting center. Will be done. At this time, the Ce concentration at the center of light emission is defined as follows. That is, the composition formula of YAG is Y ₃ Al ₅ O ₁₂ , but YAG in which a part of yttrium (Y) is replaced with Ce is expressed as YAG: Ce, and the composition formula is generally (Y _{3). -X} Ce _X ) Expressed as Al ₅ O ₁₂ . Then, the ratio of Ce to the number of atoms in the entire composition formula is expressed in the unit "at%". For example, when X = 0.1, 0.1 / (3 + 5 + 12) × 100 = 0.5, so this is defined as 0.5 at%.

LuAG is obtained by replacing all Y of 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 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 having a low Ce concentration, it is possible to disperse the heat generation points generated by the phosphor, reduce the heat density generated during fluorescence conversion, and improve the heat dissipation property of the entire phosphor layer. It is possible to prevent the temperature from rising. As a result, even when excited by a laser or the like having high energy, it becomes difficult to reach a temperature at which the emission performance of the phosphor deteriorates, 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. As a result, since the Ce concentration is not too small, it is possible to suppress a decrease in luminous efficiency.

The Ce concentration of the phosphor particles can be analyzed by ICP or XRF. In either method, a phosphor having a known Ce concentration is used as a calibration curve. The Ce concentration may be obtained as an average value of a plurality of analysis values.

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

The average particle size 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. This is because the emission intensity of the converted light is increased because it is 1 μm or more, and the emission intensity of the wavelength conversion member 10 is increased. Further, since it is 30 μm or less, the temperature of each phosphor particle 16 can be kept low, and temperature quenching can be suppressed. In the present specification, the average particle size is the median size (D50) or the average particle size of the particles obtained by analyzing the SEM image. The average particle size, which is the median size (D50), can be measured by using a dry measurement or a wet measurement of a laser diffraction / scattering type particle size distribution measuring device. Further, 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 of the phosphor layer 14 in the direction perpendicular to the plane direction, for example, at a magnification of 1000 times. Image analysis such as binarization is performed on the SEM image, 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 obtained 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 as to have an overall average particle diameter for the phosphor particles 16 contained in the phosphor layer 14. It is assumed that cross-sectional images (for example, three or more) of a plurality of locations on the layer 14 are acquired.

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

The translucent substance is the emission of light that escapes from the opposite side when light is vertically incident on a target substance of 0.5 mm in the wavelength region of visible light (λ = 380 to 780 nm). A substance whose bundle has a property of exceeding 80% of the incident light.

By combining the wavelength conversion member 10 with a light source, it is possible to form a light emitting device capable of maintaining high light emission intensity even at high power and suppressing a decrease in light emission efficiency. In particular, the wavelength conversion member 10 is in a predetermined range in which the Ce concentration of the phosphor particles 16 is low, the phosphor layer 14 is thinner than the base material 12 that functions as a heat dissipation plate, 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]
(A) and (b) of FIG. 2 are schematic views showing a transmission type and a reflection type light emitting device 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 reflection type light emitting device 40 includes a light source 50 and a reflection type wavelength conversion member 10. As the light source 50, an LED, a laser diode, or the like that generates light source light having a wavelength in a specific range can be used. Since the wavelength conversion member 10 can maintain high emission intensity even at 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 for manufacturing the wavelength conversion member of the present invention. First, a printing paste is prepared. First, phosphor particles having a predetermined Ce concentration and average particle size 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 or the like can be used for mixing. As the solvent, a high boiling point solvent such as α-terpineol, butanol, isophorone, and glycerin can be used.

Further, the inorganic binder is preferably an organic silicate such as ethyl silicate. By using the organic silicate, the phosphor particles are dispersed in the entire printing paste, and a printing paste having an appropriate viscosity can be prepared. For example, when ethyl silicate is used as the inorganic binder, the mass of ethyl silicate is 70 wt% or more and 100 wt% or less, preferably 80 wt% or more and 90 wt% or less, based on the mass of water and the catalyst. In addition, the inorganic binder is prepared by reacting a raw material containing at least one of a group consisting of a silicon oxide precursor, a silicic acid compound, silica, and amorphous silica, which becomes silicon oxide by hydrolysis or oxidation, at room temperature. , It may be obtained by 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 preparing the printing paste, the printing paste is applied onto the base material 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, or an inkjet method. 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 in an atmospheric furnace to prepare a phosphor layer (step S4). The firing temperature is preferably 150 ° C. or higher and 500 ° C. or lower, and the firing time is preferably 0.5 hours or longer and 2.0 hours or lower. The rate of temperature rise is preferably 50 ° C./h or more and 200 ° C./h or less. Further, a drying step may be provided before firing.

By such a manufacturing process, a wavelength conversion member in which the phosphor particles are uniformly present in the entire phosphor layer can be easily manufactured. The obtained wavelength conversion member can maintain high emission intensity even at high power and can suppress a decrease in luminous efficiency.

[Example]
(Sample preparation method)
Fluorescent particles (YAG: Ce particles and LuAG: Ce particles) having an average particle size of 6 μm and a Ce concentration of 0.03 at% to 0.90 at% were prepared. These phosphor particles were weighed and mixed with α-terpineol (solvent) to prepare a dispersant, and mixed with ethyl silicate (inorganic binder) to prepare a printing paste.

Next, using a screen printing method, a printing paste was applied to a base material (sapphire base material or an aluminum base material coated with silver on aluminum) to a thickness of 8 to 220 μm after firing. After coating, it 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 atmospheric furnace and calcined for 30 minutes to complete the sample.

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

(Sample evaluation method)
Each completed sample was subjected to a reflective or transmissive emission intensity test by excitation with multiple lasers with a maximum input of 24 W. The wavelength of the light source light was adjusted to 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 a 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 planar convex lens 720, a biconvex lens 730, a bandpass 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 bandpass filter 735 is a filter that cuts light with a wavelength of 480 nm as a threshold, and when measuring transmitted light source light (absorbed light), a filter that cuts the side having a large wavelength is used. Further, when measuring the emission intensity of the converted light, a filter that cuts the side having a small wavelength is used. In this way, in order to separate the transmitted light source light from the converted light, it is installed between the biconvex lens and the power meter.

In the system configured in this way, the light source light entering the planar convex lens 720 is focused on the focal point on the sample S of the wavelength conversion member. Then, the synchrotron radiation generated from the sample S is collected by the biconvex lens 730, and the intensity of the collected light cut by the bandpass 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 narrowing the irradiation area, the energy density per unit area can be increased even with a low-power laser. This energy density is defined as the laser power density. Further, the reflection type evaluation system can be evaluated by the same system except that the focused light source light and the converted light are reflected by the base material of the sample.

5 and 6 are graphs showing the emission intensities of the reflective samples 1 to 5 and the transmissive samples 6 to 10 when the laser power density (laser input) is taken on the horizontal axis, respectively. The above emission intensity test was performed on each sample, and the peak laser input, peak emission intensity and 3W emission intensity were calculated. The peak laser input is a laser input that maximizes the emission intensity when the laser power density (laser input) is taken on the horizontal axis. The peak emission intensity was defined as the emission intensity with respect to the peak laser input. The peak emission intensity and the emission intensity at 3 W are represented by relative values when the emission intensity of the wavelength conversion member of the sample 1 is 100 for the reflection type and 100 is the emission intensity of the wavelength conversion member of the sample 6 for the transmission type. Further, FIG. 7 is a table showing various conditions of the sample and the results of the peak laser input, the peak emission intensity, and the emission intensity at 3 W (luminous efficiency). For samples 11 to 20, each value was calculated in the same manner as described above.

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

The peak laser input was larger than 3 W, the peak emission intensity was higher than 100 as a pass, and the one that failed was indicated by x. Further, the light emission intensity (luminous efficiency) at 3 W preferably has a relative value of 35 or more, and more preferably 40 or more. This is because if the luminous efficiency is low, the proportion of light source light that is transmitted or reflected without being absorbed by the phosphor particles increases, so if this proportion is excessive, it is necessary to control the light source light that is transmitted or reflected and emitted. Because it comes out. Therefore, those having 40 or more are represented by ◯, and those having less than 40 are represented by Δ.

Samples 1 to 5 are reflective wavelength conversion members, and YAG: Ce particles are used as phosphor particles to keep the thickness of the base material and the thickness (thickness) of the phosphor layer constant and change the Ce concentration. This is a sample. Since the sample 1 had a high Ce concentration, heat could not be efficiently dispersed in the phosphor layer, and the temperature was quenched with a low input of 3 W. Therefore, a high energy excitation source cannot be used. Since the samples 2 to 4 had a Ce concentration in an appropriate range, the heat dispersibility in the phosphor layer was improved, and the peak laser input and the peak emission intensity were improved. In addition, the relative value of the luminous efficiency was kept at 40 or more with respect to the sample 1 which is the reference of the reflection type. In Sample 5, since the Ce concentration was low, the peak laser input and the peak emission intensity were improved, but the relative value of the luminous 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 base material and the thickness of the phosphor layer are kept constant, and the Ce concentration is changed. is there. Since the sample 6 had a high Ce concentration, heat could not be efficiently dispersed in the phosphor layer, and the temperature was extinguished at 3 W. Therefore, a high energy excitation source cannot be used. Since the samples 7 to 9 had a Ce concentration in an appropriate range, the heat dispersibility in the phosphor layer was improved, and the peak laser input and the peak emission intensity were improved. In addition, the relative value of the luminous efficiency was kept at 40 or more with respect to the sample 6 which is the reference of the transmission type. Since the Ce concentration of sample 10 was low, the peak laser input and the peak emission intensity were improved, but the relative value of the luminous efficiency was less than 35. The reason why the transmission type sample 10 has a lower relative value of luminous efficiency than the reflection type sample 5 is that in the case of the reflection type, when the light source light that was not first absorbed by the phosphor particles is reflected and returned. This is probably because it may be absorbed by the phosphor particles.

Samples 11, 12, 13 and 14 are transmission type wavelength conversion members, respectively, and use YAG: Ce particles as phosphor particles to keep the thickness of the base material and the Ce concentration constant and to increase the thickness of the phosphor layer. It is a changed sample. Since the sample 11 has a thin film thickness, the luminous efficiency is lowered. It is considered that this is because if the film thickness is too thin, the amount of phosphor that contributes to light emission decreases. Since the film thickness of the sample 14 is one-fourth or more of the thickness of the base material, the peak laser input is reduced. It is considered that this is because the ratio of the thickness of the base material to the thickness of the phosphor layer became insufficient because the phosphor layer became too thick, and the heat in the phosphor layer was not efficiently dissipated by the base material. Be done.

Samples 15 and 16 are reflective wavelength conversion members, and YAG: Ce particles are used as phosphor particles, the Ce concentration is kept constant, and the thickness of the base material is made thicker than that of Samples 1 to 5. This is a sample in which the film thickness of the phosphor layer is changed. In 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 were within an appropriate range, and all the results satisfied the criteria. In sample 16, the ratio of the thickness of the base material to the film thickness of the phosphor layer was within an appropriate range, but the film thickness of the phosphor layer was too thick, so that the peak laser input and the peak emission intensity did not meet the criteria. .. This is because if the film thickness is too thick, heat that exceeds the effect of heat dispersion in the phosphor layer due to the change in Ce concentration is generated, the heat dissipation of the phosphor layer itself is lowered, and heat is generated in the phosphor layer. It is thought that it is for muffled.

Samples 17 to 20 are reflective wavelength conversion members, in which LuAG: Ce particles are used as phosphor particles, the thickness of the base material and the film thickness of the phosphor layer are kept constant, and the Ce concentration is changed. is there. Even when LuAG: Ce particles are used, the heat dispersibility in the phosphor layer is improved at a Ce concentration in an appropriate range, as in the case where YAG: Ce particles are used, and the peak laser input and peak are used. The emission intensity at the time was improved. In addition, the relative value of the luminous efficiency was kept at 40 or more with respect to the sample 1 which is the reference of the reflection type.

From the above results, it was 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 a small amount of energy.

10 Wavelength conversion member 12 Base material 14 Fluorescent material layer 16 Fluorescent material 20 Bonding material 30 Transmission type light emitting device 40 Reflective 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 comprising a base material and a phosphor layer provided on the base material and converting light having a wavelength in a specific range into light having another wavelength.
The substrate is made of sapphire or aluminum
The thickness of the phosphor layer is 200 μm or less and one-fourth or less of the thickness of the base material in the stacking direction of the phosphor layer.
The phosphor layer is formed of a translucent inorganic material and phosphor particles bonded to the inorganic material.
The material of the phosphor particles is either YAG: Ce or LuAG: Ce.
A wavelength conversion member characterized in that 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, and the thickness 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 or 2, wherein the inorganic material fixes the fluorescent particles to each other and the fluorescent particles to the base material. The wavelength conversion member according to any one of claims 1 to 3, wherein the inorganic material is silica or aluminum phosphate. A light emitting device provided with a light source that generates light from a light source having a specific wavelength range.
A light emitting device comprising the wavelength conversion member according to any one of claims 1 to 4, which absorbs the light source light, converts it into light of another wavelength, and emits light.

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