JP2014031488A - Wavelength conversion member, light-emitting device, and method of manufacturing wavelength conversion member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength conversion member capable of emitting high-intensity fluorescence.SOLUTION: A wavelength conversion member 1 includes a wavelength conversion member body 10 and a low refractive index layer 20. The wavelength conversion member body 10 includes a glass matrix 11 and an inorganic phosphor powder 12 arranged in the glass matrix 11. The low refractive index layer 20 is arranged on a surface of the wavelength conversion member body 10. The low refractive index layer 20 has a refractive index lower than that of the inorganic phosphor powder 12.

Description

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

  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.

  The wavelength conversion member according to the present invention includes a wavelength conversion member main body and a low refractive index layer. The wavelength conversion member main body includes a glass matrix and an inorganic phosphor powder. The inorganic phosphor powder is arranged in a glass matrix. The low refractive index layer is disposed on the surface of the wavelength conversion member main body. The low refractive index layer has a refractive index lower than that of the inorganic phosphor powder.

  The low refractive index layer preferably does not contain inorganic phosphor powder.

  The low refractive index layer is preferably composed of a glass layer.

  The difference between the softening point of the glass matrix and the softening point of the glass layer is preferably 200 ° C. or less.

  The refractive index of the inorganic phosphor powder is preferably higher than the refractive index of the glass matrix.

  The thickness of the low refractive index layer is preferably 0.1 mm or less.

  The total light transmittance of the low refractive index layer is preferably 50% or more.

  The content of the inorganic phosphor powder in the wavelength conversion member body is preferably 20% by volume or more.

The difference between the thermal expansion coefficient of the wavelength conversion member main body and the thermal expansion coefficient of the low refractive index layer is preferably 100 × 10 ⁻⁷ / ° C. or less.

  The wavelength conversion member main body has a light incident surface and a light output surface, and a low refractive index layer may be provided on both the light output surface and the light incident surface.

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

  In the method for manufacturing a wavelength conversion member according to the present invention, a layer containing glass powder is formed on the surface of a raw ceramic body containing inorganic phosphor powder and glass powder. By baking the raw ceramic body and the layer containing glass powder, the wavelength conversion member body is formed from the raw ceramic body, and the glass layer is formed from the layer containing glass powder.

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

FIG. 1 is a schematic cross-sectional view of a wavelength conversion member according to an embodiment of the present invention. FIG. 2 is a schematic view of a light emitting device according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of a wavelength conversion member in a modified example.

  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)
FIG. 1 is a schematic cross-sectional view of a wavelength conversion member in the present embodiment.

  As shown in FIG. 1, the wavelength conversion member 1 includes a wavelength conversion member main body 10 and a glass layer 20.

(Wavelength conversion member body 10)
The wavelength conversion member main body 10 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, more 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.

  The refractive index of the inorganic phosphor powder 12 is higher than the refractive index of the glass constituting the glass matrix 11 and the glass layer 20. The refractive index of the inorganic phosphor powder 12 is 0.05 or more, and further 0.1 or more higher than the refractive index of the glass constituting the glass matrix 11 or the glass layer 20.

  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.

  Content of the inorganic fluorescent substance powder 12 in the wavelength conversion member main body 10 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 body 10 is preferably 20% by volume or more, more preferably 30% by volume or more, and 40% by volume. More preferably, it is the above. However, if the content of the inorganic phosphor powder 12 is too high, the strength of the wavelength conversion member body 10 may be too low. Therefore, the content of the inorganic phosphor powder 12 in the wavelength conversion member main body 10 is preferably 95% by volume or less, and more preferably 90% by volume or less.

  The shape dimension of the wavelength conversion member main body 10 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 main body 10 may be, for example, a plate shape whose planar shape is a rectangular shape or a circular shape. From the viewpoint of suppressing excitation light and fluorescence absorption in the wavelength conversion member body 10, the thickness of the wavelength conversion member body 10 is preferably 1 mm or less, preferably 0.5 mm or less, and 0.3 mm or less. More preferably it is. However, if the thickness of the wavelength conversion member main body 10 is too small, the amount of the inorganic phosphor powder 12 may be too small. Moreover, the intensity | strength of the wavelength conversion member main body 10 may fall. Therefore, the thickness of the wavelength conversion member main body 10 is preferably 0.03 mm or more.

  The wavelength conversion member main body 10 has at least one light entrance / exit surface. In the present embodiment, the main surface 10a of the wavelength conversion member main body 10 constitutes a light incident / exit surface.

(Glass layer 20)
The glass layer 20 is disposed on the surface of the wavelength conversion member main body 10. Specifically, the glass layer 20 is disposed on the main surface (light entrance / exit surface) 10 a of the wavelength conversion member main body 10. For this reason, at least one of the excitation light incident on the wavelength conversion member body 10 and the fluorescence emitted from the wavelength conversion member body 10 passes through the glass layer 20.

The glass layer 20 and the wavelength conversion member main body 10 are fused. From the viewpoint of increasing the adhesion strength between the glass layer 20 and the wavelength conversion member main body 10, the difference between the thermal expansion coefficient of the wavelength conversion member main body 10 and the thermal expansion coefficient of the glass layer 20 is 100 × 10 ⁻⁷ / ° C. or less. It is preferably 80 × 10 ⁻⁷ / ° C. or less, more preferably 60 × 10 ⁻⁷ / ° C. or less, and still more preferably 40 × 10 ⁻⁷ / ° C. or less. . Further, the difference between the softening point of the glass matrix contained in the wavelength conversion member body 10 and the softening point of the glass layer 20 is preferably 200 ° C. or less, more preferably 150 ° C. or less, and 100 ° C. or less. More preferably.

  It is preferable that the glass layer 20 does not substantially contain a phosphor powder such as the inorganic phosphor powder 12 or an additive having a higher refractive index than the glass matrix. That is, it is preferable that the glass layer 20 consists essentially of a glass matrix. The refractive index (nd) of the glass layer 20 is preferably 1.40 to 1.90, and more preferably 1.45 to 1.85.

The glass layer 20 can be made of, for example, phosphate glass such as borosilicate glass or SnO—P ₂ O ₅ glass. The softening point of the glass layer 20 is preferably 250 ° C to 1000 ° C, and more preferably 300 ° C to 850 ° C.

  When the thickness of the glass layer 20 that does not include the inorganic phosphor powder 12 is large, the content of the inorganic phosphor powder 12 in the entire wavelength conversion member 1 tends to decrease. In addition, excitation light and fluorescence are easily absorbed. For this reason, the thickness of the glass layer 20 is preferably 0.1 mm or less, more preferably 0.05 mm or less, further preferably 0.03 mm or less, and 0.02 mm or less. Particularly preferred. The lower limit of the thickness of the glass layer 20 is usually about 0.003 mm, and preferably about 0.01 mm.

  Further, from the viewpoint of making the excitation light and fluorescence difficult to absorb in the glass layer 20, the total light transmittance of the glass layer 20 is preferably 50% or more, more preferably 65% or more, and 80% or more. More preferably.

  As described above, the wavelength conversion member main body 10 includes the inorganic phosphor powder 12 having a high refractive index. The inorganic phosphor powder 12 is exposed on the surface of the wavelength conversion member main body 10. That is, the surface of the wavelength conversion member main body 10 includes a region constituted by the glass matrix 11 and a region constituted by the inorganic phosphor powder 12. As described above, the inorganic phosphor powder 12 has a higher refractive index than the glass matrix 11. For this reason, the light reflectance in the area | region comprised with the inorganic fluorescent substance powder 12 of the surface of the wavelength conversion member main body 10 is higher than the light reflectance in the area | region comprised with the glass matrix 11 of the surface of the wavelength conversion member main body 10. . For this reason, in the case where the glass layer 20 is not provided, a region made of the inorganic phosphor powder 12 having a high light reflectance exists on the surface of the wavelength conversion member main body 10, and thus the light entrance / exit surface of the wavelength conversion member main body 10. The light reflectivity at is increased. Therefore, the incident efficiency of the excitation light into the wavelength conversion member body 10 is lowered, or the emission efficiency of the fluorescence from the wavelength conversion member body 10 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 12 is increased in order to increase the intensity of the obtained fluorescence, the proportion of the inorganic phosphor powder 12 in the light entrance / exit surface of the wavelength conversion member body 10 increases. Therefore, a portion having a high light reflectivity increases on the light entrance / exit surface of the wavelength conversion member main body 10, and the fluorescence intensity may not be improved as expected.

  Here, in the wavelength conversion member 1, the glass layer which has a refractive index lower than the inorganic fluorescent substance powder 12 on the main surface 10a which comprises the light entrance / exit surface of the wavelength conversion member main body 10 containing the inorganic fluorescent substance powder 12. 20 is provided. For this reason, the light reflectance in the light entrance / exit surface of the wavelength conversion member 1 is low. Therefore, it is possible to effectively suppress a decrease in the incident efficiency of excitation light and a decrease in the emission efficiency of fluorescence caused by interface reflection. Therefore, the intensity of the fluorescence emitted from the wavelength conversion member 1 can be increased.

  From the viewpoint of obtaining higher intensity fluorescence, it is preferable that the glass layer 20 does not substantially contain the inorganic phosphor powder 12. The refractive index of the glass layer 20 is preferably less than or equal to the refractive index of the inorganic phosphor powder 12, more preferably 0.05 or more lower than the refractive index of the inorganic phosphor powder 12, and 0.1 or more lower. 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 main body 10, 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.

  In addition, in this embodiment, the example in which the glass layer 20 was provided only on the main surface on the opposite side to the reflection member 50 of the wavelength conversion member main body 10 was demonstrated. However, the present invention is not limited to this configuration. For example, the glass layer 20 may be provided on the main surface on the side opposite to the reflecting member 50 of the wavelength conversion member main body 10 and also on the main surface on the reflecting member 50 side. Further, for example, the glass layer 20 may be provided only on the main surface of the wavelength conversion member main body 10 on the reflecting member 50 side.

(Manufacturing method of wavelength conversion member 1)
Next, an example of the manufacturing method of the wavelength conversion member 1 is demonstrated.

  First, a layer containing glass powder is formed on the surface of a raw ceramic body containing inorganic phosphor powder 12 and glass powder for constituting glass matrix 11.

  Specifically, a first ceramic green sheet containing glass powder and inorganic phosphor powder 12 is produced. Moreover, the 2nd ceramic green sheet containing glass powder for forming the glass layer 20 is produced.

  Next, the first ceramic green sheet and the second ceramic green sheet are appropriately laminated, and the inorganic phosphor powder 12 and the glass powder for constituting the glass matrix 11 are included by pressing as necessary. A laminate in which a layer containing glass powder is formed on the surface of the raw ceramic body is produced.

  Next, the wavelength conversion member main body 10 is formed from a raw ceramic body by firing the laminate, and the glass layer 20 is formed from a layer containing glass powder. The wavelength conversion member 1 can be completed by the above process.

  First, only the first ceramic green sheet is fired to produce the wavelength conversion member body 10, and then a glass film for forming the glass layer 20 is laminated on the main surface 10a of the wavelength conversion member body 10, The wavelength conversion member 1 may be produced by thermocompression bonding.

  Moreover, after producing the wavelength conversion member main body 10, you may form the glass layer 20 using a sol-gel method.

(Modification)
In the said embodiment, the example in which the glass layer 20 was provided on one main surface 10a of the wavelength conversion member main body 10 was demonstrated. However, the present invention is not limited to this configuration. For example, as shown in FIG. 3, when the wavelength conversion member main body 10 has a main surface 10a constituting a light incident surface and a main surface 10b constituting a light emitting surface, the main surface It is preferable that the glass layer 20 is arranged on both surfaces of 10a and the main surface 10b. In this case, the incident efficiency of the excitation light to the wavelength conversion member body 10 can be increased, and the emission efficiency of the fluorescence from the wavelength conversion member body 10 can be increased.

  In the said embodiment, the example in which the glass layer 20 was provided as a low-refractive-index layer was demonstrated. However, the present invention is not limited to this configuration. When the refractive index of the layer disposed on the surface of the wavelength conversion member main body is lower than the refractive index of the inorganic phosphor powder, the effect described in the above embodiment can be obtained. Therefore, the low refractive index layer is not particularly limited as long as it is lower than the refractive index of the inorganic phosphor powder 12. The low refractive index layer may be made of a resin, for example.

  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: YAG phosphor powder of 30 Volume%: Mixing was performed using a vibration mixer so as to be 70 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. The slurry was applied on a polyethylene terephthalate film using a doctor blade method and dried to prepare a first ceramic green sheet. The blade gap was 200 μm, and the thickness of the obtained first ceramic green sheet was 100 μm.

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.

  An appropriate amount of binder, plasticizer, solvent, etc. was added to the obtained glass powder and 50 g of powder, and kneaded for 24 hours to obtain a slurry. The slurry was applied on a polyethylene terephthalate film using a doctor blade method and dried to prepare a second ceramic green sheet. The gap of the blade was 50 μm, and the thickness of the obtained second ceramic green sheet was 25 μm.

  The first ceramic green sheet and the second ceramic green sheet were superposed and a laminate was produced by applying a pressure of 10 kPa at 80 ° C. for 5 minutes using a thermocompression bonding machine. The produced laminate was degreased at 500 ° C. for 1 hour in the air. Then, the wavelength conversion member was produced by baking the laminated body which carried out the degreasing process for 20 minutes at 600 degreeC. After firing, the thickness of the wavelength conversion member main body was 80 μm, and the thickness of the glass layer was 20 μm.

(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 diameter (D ₅₀ ) of 15 μm were vibrated so that the glass powder: YAG phosphor powder was 30% by volume: 70% 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. The slurry was applied on a polyethylene terephthalate film using a doctor blade method and dried to prepare a first ceramic green sheet. The blade gap was 200 μm, and the thickness of the obtained first ceramic green sheet was 100 μm.

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 by a ball mill to obtain a glass powder having an average particle diameter (D ₅₀ ) of 2 μm.

  An appropriate amount of binder, plasticizer, solvent, etc. was added to the obtained glass powder and 50 g of powder, and kneaded for 24 hours to obtain a slurry. The slurry was applied on a polyethylene terephthalate film using a doctor blade method and dried to prepare a second ceramic green sheet. The gap of the blade was 50 μm, and the thickness of the obtained second ceramic green sheet was 25 μm.

  The first ceramic green sheet and the second ceramic green sheet were superposed and a laminate was produced by applying a pressure of 10 kPa at 80 ° C. for 5 minutes using a thermocompression bonding machine. In the air, the prepared laminate was degreased at 500 ° C. for 1 hour. Then, the wavelength conversion member was produced by baking the laminated body which carried out the degreasing process for 20 minutes at 600 degreeC. The thickness of the wavelength conversion member after firing was 80 μm for the wavelength conversion member body and 20 μm for the glass layer.

(Example 3)
A wavelength conversion member having a configuration substantially similar to that of Example 1 except that the thickness of the glass layer was 0.08 mm was produced by a substantially similar method.

(Comparative example)
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 by 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 diameter (D ₅₀ ) of 15 μm were vibrated so that the glass powder: YAG phosphor powder was 30% by volume: 70% 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 ceramic green sheet was degreased at 500 ° C. for 1 hour in the air, and then baked at 600 ° C. for 20 minutes to prepare a wavelength conversion member. That is, the wavelength conversion member according to Comparative Example 1 has substantially the same configuration as the wavelength conversion member according to Example 1 except that it does not have a glass layer.

(Evaluation)
A reflective substrate (MIRO-SILVER manufactured by Material House Co., Ltd.) is provided on one main surface of each sample produced in each of Examples 1 to 3 and Comparative Example (for Examples 1 to 3, the surface on the wavelength conversion member main body side). Was pasted using an adhesive (a highly reflective resin manufactured by Shin-Etsu Chemical Co., Ltd.) to prepare a measurement sample. A measurement sample is fixed on a Peltier device set at 15 ° C., an output is 30 W, a blue laser beam having a wavelength of 440 nm is irradiated on the measurement sample, and the obtained fluorescence is transmitted through an optical fiber to a small spectroscope (USB-4000, The product was received by Ocean Optics, and the emission spectrum was obtained. The intensity of fluorescence was determined from the emission spectrum. The results are shown in Table 1 below.

  The thermal expansion coefficient and softening point shown in Table 1 were measured as follows. The thermal expansion coefficient was measured in a range of 25 ° C. to 250 ° C. using DILATO manufactured by Mac Science. The softening point was measured using Rigaku TAS-200. The total light reflectance was measured using a UV 2500PC manufactured by Shimadzu Corporation in the wavelength range of 350 nm to 800 nm.

  From the results shown in Table 1, it can be seen that the intensity of fluorescence obtained can be increased by providing a glass layer on the surface of the wavelength conversion member body.

DESCRIPTION OF SYMBOLS 1,3 ... Wavelength conversion member 2 ... Light-emitting device 10 ... Wavelength conversion member main body 10a, 10b ... Main surface 11 of wavelength conversion member main body ... Glass matrix 12 ... Inorganic fluorescent substance powder 20 ... Glass layer 30 ... Light source 40 ... Beam splitter 50 ... Reflection member

Claims (12)

A wavelength conversion member body comprising a glass matrix and an inorganic phosphor powder disposed in the glass matrix;
A low refractive index layer disposed on the surface of the wavelength conversion member body, having a refractive index lower than the refractive index of the inorganic phosphor powder;
A wavelength conversion member comprising:   The wavelength conversion member according to claim 1, wherein the low refractive index layer does not contain inorganic phosphor powder.   The wavelength conversion member according to claim 1 or 2, wherein the low refractive index layer is formed of a glass layer.   The wavelength conversion member according to claim 3, wherein a difference between a softening point of the glass matrix and a softening point of the glass layer is 200 ° C or less.   The wavelength conversion member according to any one of claims 1 to 4, wherein a refractive index of the inorganic phosphor powder is higher than a refractive index of the glass matrix.   The wavelength conversion member according to any one of claims 1 to 5, wherein a thickness of the low refractive index layer is 0.1 mm or less.   The wavelength conversion member as described in any one of Claims 1-6 whose total light transmittance of the said low-refractive-index layer is 50% or more.   The wavelength conversion member according to any one of claims 1 to 7, wherein the content of the inorganic phosphor powder in the wavelength conversion member main body is 20% by volume or more. The wavelength as described in any one of Claims 1-8 whose difference of the thermal expansion coefficient of the said wavelength conversion member main body and the thermal expansion coefficient of the said low-refractive-index layer is ^100x10 < ^-7 > / degrees C or less. Conversion member.   The said wavelength conversion member main body has a light-incidence surface and a light-projection surface, The said low-refractive-index layer is provided on both surfaces of the said light-projection surface and the said light-incidence surface of Claim 1-9 The wavelength conversion member as described in any one. The wavelength conversion member according to any one of claims 1 to 10,
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: It is a manufacturing method of the wavelength conversion member according to claim 3,
Forming a layer containing glass powder on the surface of a raw ceramic body containing the inorganic phosphor powder and glass powder;
Forming the wavelength conversion member body from the raw ceramic body by firing the raw ceramic body and the layer containing the glass powder, and forming the glass layer from the layer containing the glass powder When,
A method for manufacturing a wavelength conversion member.

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