JP2014015359A - Method of manufacturing wavelength conversion member, wavelength conversion member, and light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength conversion member capable of emitting high-intensity fluorescence.SOLUTION: A raw ceramic element body 3 containing a glass powder and an inorganic phosphor powder 12 is prepared. A firing step of firing the raw ceramic element body 3 to obtain a wavelength conversion member 1 including a glass matrix 11 and the inorganic phosphor powder 12 arranged in the glass matrix 11 is performed. In the firing step, the raw ceramic element body 3 is heated to a temperature at which the viscosity of glass is 10dPa s or less.

Description

  The present invention relates to a wavelength conversion member manufacturing method, a wavelength conversion member, and a light emitting device.

  Conventionally, a wavelength conversion member that emits fluorescence having a wavelength different from that of excitation light when excitation light is incident is known. Patent Document 1 proposes a wavelength conversion member in which an inorganic phosphor powder is dispersed in a glass matrix as an example of a wavelength conversion member.

JP 2003-258308 A

  In recent years, there is a desire to further increase the intensity of fluorescence emitted from the wavelength conversion member. As a method for increasing the intensity of fluorescence, a method for increasing the concentration of the phosphor in the wavelength conversion member is conceivable. However, even when the concentration of the phosphor is increased, the intensity of the fluorescence emitted from the wavelength conversion member may not be sufficiently increased.

  The main object of the present invention is to provide a wavelength conversion member capable of emitting high-intensity fluorescence.

In the method for manufacturing a wavelength conversion member according to the present invention, a raw ceramic body including glass powder and inorganic phosphor powder is prepared. By firing the raw ceramic body, a firing process is performed to obtain a wavelength conversion member including a glass matrix and an inorganic phosphor powder disposed in the glass matrix. In the firing step, the raw ceramic body is heated to a temperature at which the glass has a viscosity of 10 ⁷ dPa · s or less.

  In the method for producing a wavelength conversion member according to the present invention, the ratio of glass powder to inorganic phosphor powder in the raw ceramic body ((glass powder) :( inorganic phosphor powder)) is 90:10 by volume%. It is preferable to be within the range of 40:60.

  In the method for manufacturing a wavelength conversion member according to the present invention, the refractive index of the inorganic phosphor powder is preferably higher than the refractive index of the glass matrix.

  The wavelength conversion member according to the present invention includes a glass matrix and an inorganic phosphor powder. The inorganic phosphor powder is arranged in a glass matrix. The density | concentration of the inorganic fluorescent substance powder in the surface layer of a glass matrix is lower than the density | concentration of the inorganic fluorescent substance powder in the center part of a glass matrix.

  In the wavelength conversion member according to the present invention, in the surface layer of the glass matrix, the concentration of the inorganic phosphor powder may gradually decrease from the center side to the surface side of the glass matrix.

  In the wavelength conversion member according to the present invention, the refractive index of the inorganic phosphor powder is preferably higher than the refractive index of the glass matrix.

  In the wavelength conversion member according to the present invention, the content of the inorganic phosphor powder in the glass matrix is preferably within the range of 10% by volume to 60% by volume.

  The light emitting device according to the present invention includes the wavelength conversion member and a light source. The light source irradiates the wavelength conversion member with light having an excitation wavelength of the inorganic phosphor powder.

  ADVANTAGE OF THE INVENTION According to this invention, the wavelength conversion member which can radiate | emit high intensity | strength fluorescence can be provided.

It is a schematic sectional drawing of the wavelength conversion member in one Embodiment of this invention. It is a schematic diagram of the light-emitting device in one Embodiment of this invention. 1 is a schematic cross-sectional view of a raw ceramic body in an embodiment of the present invention. 2 is a photograph of the surface of a wavelength conversion member produced in Example 1. 4 is a photograph of the surface of a wavelength conversion member produced in Comparative Example 1.

  Hereinafter, an example of the preferable form which implemented this invention is demonstrated. However, the following embodiment is merely an example. The present invention is not limited to the following embodiments.

  Moreover, in each drawing referred in embodiment etc., the member which has a substantially the same function shall be referred with the same code | symbol. The drawings referred to in the embodiments and the like are schematically described. A ratio of dimensions of an object drawn in a drawing may be different from a ratio of dimensions of an actual object. The dimensional ratio of the object may be different between the drawings. The specific dimensional ratio of the object should be determined in consideration of the following description.

(Wavelength conversion member 1)
FIG. 1 is a schematic cross-sectional view of a wavelength conversion member 1 in the present embodiment. The shape dimension of the wavelength conversion member 1 can be appropriately set according to the shape dimension of the device in which the wavelength conversion member 1 is used. The wavelength conversion member 1 may be, for example, a plate shape whose planar shape is a rectangular shape or a circular shape.

  As shown in FIG. 1, the wavelength conversion member 1 includes a glass matrix 11 and an inorganic phosphor powder 12.

The glass matrix 11 is not particularly limited as long as it is suitable as a dispersion medium for the inorganic phosphor powder 12. The glass matrix 11 can be made of, for example, phosphate glass such as borosilicate glass or SnO—P ₂ O ₅ glass. The refractive index of the glass matrix 11 is preferably 1.45 to 2.00, and preferably 1.47 to 1.90. The softening point of the glass matrix 11 is preferably 250 ° C to 1000 ° C, and more preferably 300 ° C to 850 ° C.

  The inorganic phosphor powder 12 is disposed in the glass matrix 11. Specifically, the inorganic phosphor powder 12 is dispersed in the glass matrix 11.

  The inorganic phosphor powder 12 is, for example, an oxide phosphor, a nitride phosphor, an oxynitride phosphor, a chloride phosphor, an acid chloride phosphor, a sulfide phosphor, an oxysulfide phosphor, or a halide fluorescence. Body, chalcogenide phosphor, aluminate phosphor, halophosphate phosphor, and garnet compound phosphor.

Specific examples of the inorganic phosphor powder 12 that emits blue fluorescence when irradiated with ultraviolet to near-ultraviolet excitation light having a wavelength of 300 nm to 440 nm include, for example, Sr ₅ (PO ₄ ) ₃ Cl: Eu ²⁺ , (Sr, Ba). MgAl ₁₀ O ₁₇ : Eu ^{2+ and the} like.

Specific examples of the inorganic phosphor powder 12 that emits green fluorescence (fluorescence having a wavelength of 500 nm to 540 nm) when irradiated with excitation light having a wavelength of 300 nm to 440 nm include, for example, SrAl ₂ O ₄ : Eu ²⁺ , SrGa ₂ S _4: ^{Eu 2+.}

Specific examples of the inorganic phosphor powder 12 that emits green fluorescence (fluorescence having a wavelength of 500 nm to 540 nm) when irradiated with blue excitation light having a wavelength of 440 nm to 480 nm include, for example, SrAl ₂ O ₄ : Eu ²⁺ , SrGa ₂ S. ₄ : Eu <^2+> etc. are mentioned.

Specific examples of the inorganic phosphor powder 12 that emits yellow fluorescence (fluorescence with a wavelength of 540 nm to 595 nm) when irradiated with ultraviolet to near ultraviolet excitation light having a wavelength of 300 nm to 440 nm include, for example, ZnS: Eu ^2+. .

As a specific example of the inorganic phosphor powder 12 that emits yellow fluorescence (fluorescence having a wavelength of 540 nm to 595 nm) when irradiated with blue excitation light having a wavelength of 440 nm to 480 nm, for example, Y ₃ (Al, Gd) ₅ O ₁₂ : Ce ²⁺ , Lu ₃ Al ₅ O ₁₂ : Ce ²⁺ , Tb ₃ Al ₅ O ₁₂ : Ce ²⁺ , La ₃ Si ₆ N ₁₁ : Ce, Ca (Si, Al) ₁₂ (O, N) ₁₆ : Eu ²⁺ , ( Si, Al) ₃ (O, N) ₄ : Eu ²⁺ , (Sr, Ba) ₂ SiO ₄ : Eu ^{2+, and the} like.

As a specific example of the inorganic phosphor powder 12 that emits red fluorescence (fluorescence having a wavelength of 600 nm to 700 nm) when irradiated with excitation light having a wavelength of 300 nm to 440 nm, for example, Gd ₃ Ga ₄ O ₁₂ : Cr ³⁺ , CaGa ₂ S ₄ : Mn ^{2+ and the} like.

Specific examples of the inorganic phosphor powder 12 that emits red fluorescence (fluorescence having a wavelength of 600 nm to 700 nm) when irradiated with blue excitation light having a wavelength of 440 nm to 480 nm include, for example, Mg ₂ TiO ₄ : Mn ⁴⁺ , K ₂ SiF. ₆ : Mn ⁴⁺ , (Ca, Sr) ₂ Si ₅ N ₈ : Eu ²⁺ , CaAlSiN ₃ : Eu ²⁺ , (Sr, Ba) ₂ SiO ₄ : Eu ²⁺ , (Sr, Ca, Ba) ₂ SiO ₄ : Eu ²⁺ Etc.

  Usually, the refractive index of the inorganic phosphor powder 12 is higher than the refractive index of the glass constituting the glass matrix 11. In general, the refractive index of the inorganic phosphor powder 12 is often 0.05 or more, more preferably 0.1 or more higher than the refractive index of the glass constituting the glass matrix 11.

  In this specification, unless otherwise specified, the refractive index means a refractive index with respect to d-line (light having a wavelength of 587.6 nm).

If the average particle size of the inorganic phosphor powder 12 is too large, the emission color may be non-uniform. Therefore, the average particle diameter (D ₅₀ ) of the inorganic phosphor powder 12 is preferably 50 μm or less, and more preferably 25 μm or less. However, if the average particle size of the inorganic phosphor powder 12 is too small, the emission intensity may be reduced. Therefore, the average particle diameter of the inorganic phosphor powder 12 is preferably 1 μm or more, and more preferably 5 μm or more.

In the present specification, the average particle diameter means the average particle diameter (D _50).

  Content of the inorganic fluorescent substance powder 12 in the wavelength conversion member 1 can be suitably set according to the intensity | strength etc. of the fluorescent substance desired. From the viewpoint of obtaining high-intensity fluorescence, the content of the inorganic phosphor powder 12 in the wavelength conversion member 1 is preferably 10% by volume or more, more preferably 20% by volume or more, and 30% by volume or more. More preferably. However, if the content of the inorganic phosphor powder 12 is too high, the strength of the wavelength conversion member 1 may be too low. Therefore, the content of the inorganic phosphor powder 12 in the wavelength conversion member 1 is preferably 60% by volume or less, and more preferably 50% by volume or less.

  The shape dimension of the wavelength conversion member 1 can be appropriately set according to the shape dimension of the device in which the wavelength conversion member 1 is used. The wavelength conversion member 1 may be, for example, a plate shape whose planar shape is a rectangular shape or a circular shape. From the viewpoint of suppressing absorption of excitation light and fluorescence in the wavelength conversion member 1, the thickness of the wavelength conversion member 1 is preferably 1 mm or less, more preferably 0.5 mm or less, and 0.3 mm or less. More preferably. However, if the thickness of the wavelength conversion member 1 is too small, the amount of the inorganic phosphor powder 12 may be too small. Moreover, the intensity | strength of the wavelength conversion member 1 may fall. Therefore, the thickness of the wavelength conversion member 1 is preferably 0.03 mm or more.

  The wavelength conversion member 1 has at least one light entrance / exit surface. In the present embodiment, the first main surface 11a of the glass matrix 11 constitutes a light entrance / exit surface.

  As described above, the wavelength conversion member includes an inorganic phosphor powder having a high refractive index. Usually, the inorganic phosphor powder is exposed on the surface of the wavelength conversion member. That is, the surface of the wavelength conversion member includes a region composed of a glass matrix and a region composed of an inorganic phosphor powder. As described above, the inorganic phosphor powder has a higher refractive index than the glass matrix. For this reason, the light reflectance in the area | region comprised with the inorganic fluorescent substance powder on the surface of a wavelength conversion member is higher than the light reflectance in the area | region comprised with the glass matrix of the surface of a wavelength conversion member. Therefore, the incident efficiency of the excitation light into the wavelength conversion member is lowered, or the emission efficiency of the fluorescence from the wavelength conversion member is lowered. In connection with this, the intensity | strength of the fluorescence obtained may become low. For example, when the content of the inorganic phosphor powder is increased in order to increase the concentration of the obtained fluorescence, the proportion of the inorganic phosphor powder in the light entrance / exit surface of the wavelength conversion member increases. Therefore, a portion having a high light reflectance increases on the light entrance / exit surface of the wavelength conversion member, and the fluorescence intensity may not be improved as expected.

  Here, in the wavelength conversion member 1, the concentration of the inorganic phosphor powder 12 in the surface layer of the glass matrix 11 is lower than the concentration of the inorganic phosphor powder 12 in the central portion of the glass matrix 11. Specifically, the concentration of the inorganic phosphor powder 12 in the surface layer on the first main surface 11a side which is the light entrance / exit surface of the glass matrix 11 is the concentration of the inorganic phosphor powder 12 in the central portion in the thickness direction of the glass matrix 11. Lower than. For this reason, for example, the area occupied by the inorganic phosphor powder 12 in the first main surface 11a constituting the light entrance / exit surface is compared with the case where the inorganic phosphor powder is uniformly dispersed in the entire glass matrix. The ratio is small. Therefore, the refractive index in the surface layer of the glass matrix 11 can be lowered. Therefore, the light reflectance at the first major surface 11a of the glass matrix 11 can be reduced.

  As described above, in the wavelength conversion member 1, even when the content of the inorganic phosphor powder 12 is increased, the light reflectance on the first main surface 11 a can be reduced. For this reason, the incident rate of excitation light and the emission rate of fluorescence can be increased. Therefore, high emission intensity of fluorescence can be realized.

  As the refractive index of the inorganic phosphor powder 12 is higher than the refractive index of the glass matrix 11, the light reflectance of the first main surface 11a when the content of the inorganic phosphor powder 12 is increased tends to increase. The effect of the present invention is easily enjoyed. Specifically, the technique of the present embodiment that can increase the emission intensity of the fluorescence of the present embodiment is more useful when the refractive index of the inorganic phosphor powder 12 is higher than the refractive index of the glass matrix 11 by 0.05 or more. Yes, more useful when higher than 0.1.

  Moreover, the light reflectance of the 1st main surface 11a at the time of raising content of the inorganic fluorescent substance powder 12 tends to increase, so that content of the inorganic fluorescent substance powder 12 is high. For this reason, the technique of the present embodiment that can increase the emission intensity of the fluorescence of the present embodiment is more useful when the content of the inorganic phosphor powder 12 in the glass matrix 11 is 10% by volume or more, and 30% by volume or more. It is further useful when the amount is 40% by volume or more.

  The surface layer on the first main surface 11a side of the glass matrix 11 may not substantially contain the inorganic phosphor powder 12. In this case, the light reflectance on the first main surface 11a can be further reduced. However, in the surface layer of the glass matrix 11, the concentration of the inorganic phosphor powder 12 may gradually decrease from the center side of the glass matrix 11 toward the surface side.

  In the present embodiment, an example in which only one main surface of the wavelength conversion member 1 is a light incident / exit surface has been described. However, the present invention is not limited to this configuration. The wavelength conversion member may have two or more light entrance / exit surfaces. In that case, the content of the inorganic phosphor powder only needs to be low in at least one of the surface layers constituting the two or more light entrance / exit surfaces, and the content of the inorganic phosphor powder is reduced in all the surface layers. More preferably.

(Light-emitting device 2)
FIG. 2 shows a light emitting device 2 using the wavelength conversion member 1. As shown in FIG. 2, the light emitting device 2 includes a light source 30 and a wavelength conversion member 1. The light source 30 irradiates the wavelength conversion member 1 with the light L1 having the excitation wavelength of the inorganic phosphor powder 12. When the light L1 enters the wavelength conversion member 1, the inorganic phosphor powder 12 absorbs the light L1 and emits fluorescence L2. Since the reflection member 50 is provided on the opposite side of the wavelength conversion member 1 from the light source 30, the fluorescence L2 is emitted toward the light source 30 side. The fluorescence L2 is reflected by the beam splitter 40 disposed between the light source 30 and the wavelength conversion member 1, and is extracted from the light emitting device 2.

  As described above, since the wavelength conversion member 1 emits high-intensity fluorescence, the light-emitting device 2 that can emit high-intensity light can be realized.

(Manufacturing method of wavelength conversion member 1)
The manufacturing method of the wavelength conversion member 1 is not specifically limited. The wavelength conversion member 1 can be manufactured, for example, by the following method.

  First, a raw ceramic body 3 (see FIG. 3) including glass powder and inorganic phosphor powder 12 is prepared. In FIG. 3, for convenience of drawing, only the inorganic phosphor powder 12 is shown, and the glass powder is not shown.

  In the raw ceramic body 3, the ratio of the glass powder to the inorganic phosphor powder 12 ((glass powder) :( inorganic phosphor powder 12)) is in the range of 90:10 to 40:60 in volume%. Preferably there is.

The average particle diameter (D ₅₀ ) of the glass powder is preferably 100 μm or less, and more preferably 50 μm or less. When the average particle diameter of the glass powder is too large, the dispersion state of the inorganic phosphor powder 12 in the wavelength conversion member 1 is inferior, and the emission color tends to vary. The lower limit of the average particle diameter (D ₅₀ ) of the glass powder is not particularly limited, but if the average particle diameter of the glass powder is too small, the production cost is likely to increase, and therefore it may be 0.1 μm or more. Preferably, it is 1 μm or more.

  The raw ceramic body 3 can be produced, for example, in the following manner. First, a ceramic green sheet containing glass powder and inorganic phosphor powder 12 is prepared. Next, the raw ceramic body 3 can be completed by laminating a plurality of the ceramic green sheets and appropriately cutting and pressing as necessary. In addition, when the thickness of the ceramic green sheet is sufficiently thick with respect to the thickness of the raw ceramic element body 3 to be manufactured, the raw ceramic element body 3 may be configured by one ceramic green sheet.

Next, the wavelength conversion member 1 is produced by firing the raw ceramic body 3. In this firing step, the raw ceramic body 3 is heated to a temperature at which the glass has a viscosity of 10 ⁷ dPa · s or less. By doing so, the flow of the glass is promoted, and the inorganic phosphor powder 12 is likely to move (sediment). As a result, the wavelength conversion member 1 in which the concentration of the inorganic phosphor powder 12 in the surface layer of the glass matrix 11 is lower than the concentration of the inorganic phosphor powder 12 in the central portion of the glass matrix 11 can be obtained. From the viewpoint of lowering the concentration of the inorganic phosphor powder 12 in the surface layer of the glass matrix 11, in the firing step, the raw ceramic body 3 is brought to a temperature at which the glass has a viscosity of 10 ^6.5 dPa · s or less. It is more preferable to heat up to a temperature of 10 ⁶ dPa · s or less. However, if the heating temperature of the raw ceramic body 3 in the firing step is too high, the shape accuracy of the obtained wavelength conversion member 1 may be too low. Further, the inorganic phosphor powder 12 may deteriorate and the fluorescence intensity may decrease. For this reason, the maximum heating temperature of the raw ceramic body 3 in the firing step is preferably a temperature at which the viscosity of the glass is 10 ⁴ dPa · s or higher, and preferably a temperature at which 10 ⁵ dPa · s or higher is reached. More preferred.

  For example, the wavelength conversion member 1 can also be manufactured by the following method. First, a first ceramic green sheet containing glass powder and an inorganic phosphor powder and a second ceramic green sheet having a smaller content of inorganic phosphor powder than the first ceramic green sheet are prepared. The second ceramic green sheet may not substantially contain the inorganic phosphor powder.

  Next, the first ceramic green sheet and the second ceramic green sheet are appropriately laminated so that the surface layer is constituted by the second ceramic green sheet, and the raw ceramic body 3 is produced. Further, between the first ceramic green sheet and the second ceramic green sheet, the concentration of the inorganic phosphor powder is between the same concentration in the first ceramic green sheet and the same concentration in the second ceramic green sheet. A ceramic green sheet may be further interposed.

  Next, the wavelength conversion member 1 can be completed by firing the raw ceramic body 3. In this manufacturing method, the firing temperature of the raw ceramic body 3 is not particularly limited.

  This manufacturing method is particularly suitable for manufacturing a wavelength conversion member in which the surface layer of the glass matrix 11 is substantially free of inorganic phosphor powder.

  Hereinafter, the present invention will be described in more detail on the basis of specific examples. However, the present invention is not limited to the following examples, and may be appropriately modified and implemented without departing from the scope of the present invention. Is possible.

Example 1
Raw materials so as to be SiO ₂ : 58%, Al ₂ O ₃ : 6%, B ₂ O ₃ : 17%, Li ₂ O: 8%, Na ₂ O: 8%, K ₂ O: 3% in mol% The glass was formed into a film by a melt quenching method. The obtained glass film was wet pulverized using a ball mill to obtain a glass powder having an average particle diameter (D ₅₀ ) of 2 μm.

The obtained glass powder and a phosphor powder of YAG (Yttrium Aluminum Garnet, Y ₃ Al ₅ O ₁₂ ) having an average particle diameter (D ₅₀ ) of 15 μm, and a glass powder: 60 phosphor powder of YAG. Volume%: Mixing was performed using a vibration mixer so as to be 40 volume%. An appropriate amount of a binder, a plasticizer, a solvent, and the like was added to 50 g of the obtained mixed powder and kneaded for 24 hours to obtain a slurry. This slurry was applied onto a polyethylene terephthalate film using a doctor blade method and dried to prepare a ceramic green sheet. The blade gap was 200 μm. The thickness of the obtained ceramic green sheet was 100 μm.

  Next, the obtained ceramic green sheet was degreased at 500 ° C. for 1 hour in the air. Then, the wavelength conversion member was produced by baking the ceramic green sheet which carried out the degreasing process at 680 degreeC (maximum temperature) for 20 minutes. After firing, the wavelength conversion member had a thickness of 80 μm.

The viscosity of the glass used in this example at 680 ° C. was 10 ^6.07 dPa · s.

(Comparative Example 1)
A wavelength conversion member having a configuration substantially similar to that of Example 1 was produced in a substantially similar method except that the ceramic green sheet was baked at 600 ° C. (maximum temperature) for 20 minutes.

In addition, the viscosity in 600 ^degreeC of the glass used in this comparative example was ^108.22 dPa * s.

(Example 2)
In mol%, SiO ₂ : 18%, B ₂ O ₃ : 38%, BaO: 3%, SrO: 7%: ZnO: 15%, Li ₂ O: 13%, ZrO ₂ : 1%, La ₂ O ₃ : The raw materials were prepared so as to be 5%, and glass was formed into a film by a melt quenching method. The obtained glass film was wet pulverized using a ball mill to obtain a glass powder having an average particle diameter (D ₅₀ ) of 2 μm.

The obtained glass powder and the YAG phosphor powder having an average particle size (D ₅₀ ) of 15 μm were vibrated so that the glass powder: YAG phosphor powder was 60% by volume: 40% by volume. Mix using a mixer. An appropriate amount of a binder, a plasticizer, a solvent, and the like was added to 50 g of the obtained mixed powder and kneaded for 24 hours to obtain a slurry. This slurry was applied onto a polyethylene terephthalate film using a doctor blade method and dried to prepare a ceramic green sheet. The gap of the blade was 200 μm, and the thickness of the obtained ceramic green sheet was 100 μm.

  Next, the obtained ceramic green sheet was degreased at 500 ° C. for 1 hour in the air. Then, the wavelength conversion member was produced by baking the ceramic green sheet which carried out the degreasing process for 20 minutes at 630 degreeC (maximum temperature). After firing, the wavelength conversion member had a thickness of 80 μm.

The viscosity of the glass used in this example at 630 ° C. was 10 ^5.84 dPa · s.

(Comparative Example 2)
A wavelength conversion member having a configuration substantially similar to that of Example 2 was produced in a substantially similar method except that the ceramic green sheet was fired at 550 ° C. (maximum temperature) for 20 minutes.

In addition, the viscosity at 550 ° C. of the glass used in this comparative example was 10 ^7.65 dPa · s.

(Fluorescence intensity measurement)
A reflective substrate (MIRO-SILVER made by Material House Co., Ltd.) and an adhesive (high reflection resin made by Shin-Etsu Chemical Co., Ltd.) are used for each sample produced in each of Examples 1 and 2 and Comparative Examples 1 and 2. A measurement sample was prepared by pasting. The measurement sample was fixed on a Peltier device set at 15 ° C., the output was 30 W, and the measurement sample was irradiated with blue laser light having a wavelength of 440 nm. The fluorescence obtained at that time was received by a small spectroscope (USB-4000, manufactured by Ocean Optics) through an optical fiber to obtain an emission spectrum. From the emission spectrum, the intensity of the obtained fluorescence was determined. The results are shown in Table 1 below.

  In addition, the softening point shown in Table 1 was measured as follows.

  Softening point: Measured with TAS-200 manufactured by Rigaku Corporation.

  Total light reflectance: Measured using a UV 2500PC manufactured by Shimadzu Corporation in the wavelength range of 350 nm to 800 nm.

(Content of inorganic phosphor powder)
The side surface of each sample produced in each of Examples 1 and 2 and Comparative Examples 1 and 2 was polished to produce a sample with an exposed cross section. The sample was observed with an electronic microscope, and the content of the inorganic phosphor powder in the surface layer and the content of the inorganic phosphor powder in the center were observed.

As a result, in Examples 1 and 2, it was confirmed that the content of the inorganic phosphor powder in the surface layer was smaller than the content of the inorganic phosphor powder in the central portion. On the other hand, in Comparative Examples 1 and 2, it was confirmed that the content of the inorganic phosphor powder in the surface layer and the content of the inorganic phosphor powder in the central portion were substantially the same. From this result, in the firing step, the raw ceramic body is heated to a temperature at which the viscosity of the glass is 10 ⁷ dPa · s or less, so that the content of the inorganic phosphor powder in the surface layer is reduced to the inorganic fluorescence in the central portion. It can be seen that the content can be smaller than the content of the body powder. In addition, the comparison between the photograph of the surface of the wavelength conversion member produced in Example 1 shown in FIG. 4 and the photograph of the surface of the wavelength conversion member produced in Comparative Example 1 shown in FIG. By heating the ceramic body to a temperature at which the viscosity of the glass is 10 ⁷ dPa · s or less, the content of the inorganic phosphor powder in the surface layer can be made smaller than the content of the inorganic phosphor powder in the central portion. I understand. Table 1 shows the area ratio of the inorganic phosphor powder in the surface of the wavelength conversion member calculated from the photographs of the surface of the wavelength conversion member produced in each of Examples 1 and 2 and Comparative Examples 1 and 2.

  From the results shown in Table 1, in Examples 1 and 2 where the content of the inorganic phosphor powder in the surface layer is less than the content of the inorganic phosphor powder in the center portion, the content of the inorganic phosphor powder in the surface layer and the center Higher fluorescence was obtained than in Comparative Examples 1 and 2 in which the content of the inorganic phosphor powder in the part was substantially equal.

DESCRIPTION OF SYMBOLS 1 ... Wavelength conversion member 2 ... Light emitting device 3 ... Raw ceramic body 11 ... Glass matrix 11a ... 1st main surface (light entrance / exit surface)
12 ... Inorganic phosphor powder 30 ... Light source 40 ... Beam splitter 50 ... Reflecting member

Claims (8)

Preparing a raw ceramic body containing glass powder and inorganic phosphor powder;
A firing step of obtaining a wavelength conversion member comprising a glass matrix and the inorganic phosphor powder disposed in the glass matrix by firing the raw ceramic body,
With
In the firing step, the raw ceramic body is heated to a temperature at which the glass has a viscosity of 10 ⁷ dPa · s or less.   The ratio of the glass powder and the inorganic phosphor powder in the raw ceramic body ((glass powder) :( inorganic phosphor powder)) is within a range of 90:10 to 40:60 in volume%. The manufacturing method of the wavelength conversion member of Claim 1.   The manufacturing method of the wavelength conversion member of Claim 1 or 2 whose refractive index of the said inorganic fluorescent substance powder is higher than the refractive index of the said glass matrix. A glass matrix;
An inorganic phosphor powder disposed in the glass matrix;
With
The wavelength conversion member whose density | concentration of the said inorganic fluorescent substance powder in the surface layer of the said glass matrix is lower than the density | concentration of the said inorganic fluorescent substance powder in the center part of the said glass matrix.   The wavelength conversion member according to claim 4, wherein in the surface layer of the glass matrix, the concentration of the inorganic phosphor powder gradually decreases from the center side to the surface side of the glass matrix.   The wavelength conversion member according to claim 4 or 5, wherein a refractive index of the inorganic phosphor powder is higher than a refractive index of the glass matrix.   The content of the said inorganic fluorescent substance powder in the said glass matrix is a wavelength conversion member as described in any one of Claims 4-6 which exists in the range of 10 volume%-60 volume%. The wavelength conversion member according to any one of claims 4 to 7,
A light source for irradiating the wavelength conversion member with light having an excitation wavelength of the inorganic phosphor powder;
A light emitting device comprising: