JP2011222751A - Wavelength conversion member and semiconductor light-emitting element device having and using the wavelength conversion member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength conversion member in which inorganic phosphor powder is scattered in a glass matrix, and which is capable of improving light distribution characteristics while maintaining a desired chromaticity range when used in a semiconductor light-emitting element device.SOLUTION: The wavelength conversion member has inorganic phosphor powder scattered in a glass matrix and a crystal is precipitated in a portion of the glass matrix. A semiconductor light-emitting element device uses the wavelength conversion member.

Description

  The present invention relates to a wavelength conversion member used as a constituent member such as a white LED.

  In recent years, white LEDs have been actively developed. White LEDs are characterized by low power consumption and long life compared to incandescent lamps and fluorescent lamps, and are being used as backlights for mobile phones and digital cameras. In the future, as a next-generation light source that replaces incandescent and fluorescent lamps, it is expected to be applied to lighting applications.

  The white LED is composed of, for example, an LED that emits blue or ultraviolet excitation light, and a wavelength conversion member in which inorganic phosphor powder is dispersed in a matrix such as a resin. The inorganic phosphor powder receives the excitation light from the LED and emits light (fluorescence) having a wavelength different from that of the excitation light. On the other hand, a part of the excitation light from the LED does not contribute to wavelength conversion and passes through the wavelength conversion member. These lights are mixed to obtain white light.

  Incidentally, white LEDs are required to have higher luminance (higher power) depending on applications. In the conventional method of dispersing the inorganic phosphor powder in the resin matrix, there is a problem that the resin matrix is discolored by heat from the LED and the luminance is lowered when used for a long time. Further, when a resin containing an inorganic phosphor powder is applied on the LED, it is difficult to adjust the thickness uniformly, and there is a problem that chromaticity variation is likely to occur.

  In order to solve these problems, a method has been proposed in which inorganic phosphor powder is dispersed in glass to completely mineralize the wavelength conversion member (see, for example, Patent Documents 1 and 2). According to this method, the heat resistance and weather resistance of the wavelength conversion member can be improved. Specifically, the white LED can be exposed to a long-time high temperature environment (for example, 150 ° C. for 600 hours) or a long-time high temperature and high humidity environment (for example, temperature 85 ° C. and humidity 85% for 2000 hours). The light emission characteristics hardly change, and there is almost no coloring or deterioration even when exposed to ultraviolet rays of sunlight for a long time. Furthermore, since it is excellent in workability, it is possible to suppress chromaticity variations due to thickness non-uniformity.

JP 2005-11933 A JP 2003-258308 A

  A wavelength conversion member obtained by dispersing inorganic phosphor powder in a glass matrix has a problem that the excitation light of the LED goes straight without being sufficiently scattered inside the wavelength conversion member. In particular, when the difference in refractive index between the glass matrix and the inorganic phosphor powder is small, the tendency is remarkable because light scattering at the interface between the two is reduced. When there are many linear components of the excitation light, the light distribution of the light emitted from the white LED is not uniform, and the chromaticity is different between the range close to the optical axis of the excitation light source and the range away from the optical axis. Increasing the content of the inorganic phosphor powder in the wavelength conversion member increases the amount of light scattering at the interface between the glass matrix and the inorganic phosphor powder as a whole, improving the light distribution characteristics, but increasing the chromaticity. Another problem arises that it deviates from the desired range.

  Accordingly, the present invention is a wavelength conversion member in which inorganic phosphor powder is dispersed in a glass matrix, and improves light distribution characteristics while maintaining a desired chromaticity range when used in a semiconductor light emitting device. It is an object of the present invention to provide a wavelength conversion member that can be used.

  As a result of intensive studies, the present inventors have found that in a wavelength conversion member in which an inorganic phosphor powder is dispersed in a glass matrix, the glass matrix has a specific state, so that the content of the inorganic phosphor powder is small. The present inventors have found that the light distribution characteristics can be improved by increasing the scattering of the excitation light, and are proposed as the present invention.

  That is, the present invention relates to a wavelength conversion member in which an inorganic phosphor powder is dispersed in a glass matrix, and crystals are precipitated in a part of the glass matrix.

  As described above, in the wavelength conversion member in which the inorganic phosphor powder is dispersed in the glass matrix, if there are many linear components of the excitation light from the LED, the light distribution of the irradiation light of the white LED is not uniform, and depending on the irradiation angle The chromaticity will change. Therefore, if the crystal is precipitated in a part of the glass matrix, the precipitated crystal increases the scattering of excitation light, and as a result, a wavelength conversion member having excellent light distribution characteristics can be obtained.

  Although it is possible to increase the scattering of excitation light by dispersing the ceramic powder in the glass matrix, in this method, when the ceramic powder is dispersed in the glass matrix, defects such as bubbles are formed at the interface between the two. Is likely to occur. Such a defect becomes a light absorption factor, which causes a decrease in luminous efficiency. On the other hand, since the wavelength conversion member of the present invention is formed by precipitating crystals from the inside of the glass matrix, the light emission efficiency is reduced without forming a light absorbing defect at the interface between the glass matrix and the crystal particles. Can be suppressed.

  Second, the wavelength conversion member of the present invention is characterized in that the difference in refractive index between the glass matrix and the precipitated crystal is 0.05 or more.

  According to the said structure, excitation light is easy to be scattered by the precipitation crystal | crystallization, and it becomes easy to obtain the wavelength conversion member excellent in the light distribution characteristic.

  Third, the wavelength conversion member of the present invention is characterized in that the precipitated crystal is at least one selected from wollastonite, anorthite, garnite, and spinel.

  Fourth, the wavelength conversion member of the present invention is characterized in that the parallel light transmittance measured in accordance with JIS K7105 is 5% or less and the haze is 90% or more.

  Fifth, the wavelength conversion member of the present invention contains 0.1 to 10% by mass of ceramic powder.

  According to the said structure, the effect which scatters excitation light becomes larger and it becomes easy to obtain the wavelength conversion member excellent in the light distribution characteristic.

  Sixth, in the wavelength conversion member of the present invention, the inorganic phosphor powder is selected from oxides, nitrides, oxynitrides, sulfides, oxysulfides, rare earth sulfides, aluminate chlorides, and halophosphates. It is characterized by being at least one kind.

  Seventh, the present invention relates to a semiconductor light-emitting element device using any of the wavelength conversion members described above.

  The wavelength conversion member of the present invention is obtained by dispersing inorganic phosphor powder in a glass matrix.

  The glass matrix has a role as a medium for stably holding the inorganic phosphor powder. Further, since the reactivity with the inorganic phosphor powder varies depending on the glass composition of the glass matrix, it is preferable to select a glass composition suitable for the inorganic phosphor powder to be used. Furthermore, it is also important to determine the content of the inorganic phosphor powder and the thickness of the wavelength conversion member so that the desired chromaticity can be obtained.

Examples of the glass that can be used for the glass matrix include SiO ₂ —B ₂ O ₃ —RO-based glass (R is at least one of Mg, Ca, Sr, and Ba). Use of SiO ₂ —B ₂ O ₃ —RO-based glass is preferable because crystals such as wollastonite and anorthite can be precipitated from the glass.

The SiO ₂ -B ₂ O ₃ -RO based glass, for example, in mol% _{composition, SiO 2 30~80%, B 2} O 3 1~40%, 0~10% MgO, CaO 0~30%, SrO 0~20%, BaO 0~40%, MgO + CaO + SrO + BaO 5~45%, Al 2 O 3 0~10%, those containing 0% ZnO preferred.

SiO ₂ is a component that forms a glass network and constitutes crystals such as wollastonite and anorthite. The content of SiO ₂ is preferably 30 to 80%, particularly preferably 40 to 60%. When the content of SiO ₂ is less than 30%, chemical durability tends to deteriorate. Moreover, it becomes difficult to precipitate crystals. On the other hand, if the content of SiO ₂ exceeds 80%, the firing temperature becomes high, and the inorganic phosphor powder tends to deteriorate.

B ₂ O ₃ is a component having a great effect of improving the meltability by lowering the melting temperature. The content of B ₂ O ₃ is preferably 1 to 40%, 5 to 35%, particularly preferably 10 to 30%. If the content of B ₂ O ₃ is less than 1%, the effect is difficult to obtain. On the other hand, when the content of B ₂ O ₃ exceeds 40%, chemical durability tends to deteriorate.

  MgO is a component that improves the meltability by lowering the melting temperature. The content of MgO is preferably 0 to 10%, particularly preferably 0.1 to 5%. When the content of MgO exceeds 10%, chemical durability tends to deteriorate. In addition, since MgO is a component of spinel, it is preferable to add MgO positively when the crystal is precipitated.

  CaO is a component that improves the meltability by lowering the melting temperature. CaO is a structural component of crystals such as wollastonite and anorthite. The CaO content is preferably 0 to 30%, particularly preferably 3 to 20%. When the content of CaO is more than 25%, chemical durability tends to deteriorate. Since CaO is a constituent of wollastonite and anorthite crystals, it is preferable to add CaO positively when these crystals are precipitated.

  SrO is a component that improves the meltability by lowering the melting temperature. The SrO content is preferably 0 to 20%, 0 to 10%, particularly preferably 0.1 to 5%. If the SrO content is more than 10%, chemical durability tends to deteriorate.

  BaO is a component that improves the meltability by lowering the melting temperature and suppresses the reaction with the inorganic phosphor powder. The BaO content is preferably 0 to 40%, particularly preferably 5 to 30%. When the content of BaO exceeds 40%, the chemical durability tends to deteriorate.

  In order to improve the meltability without deteriorating the chemical durability, the total amount of MgO, CaO, SrO and BaO is preferably 5 to 45%, particularly 10 to 40%. When the total amount of these components is less than 5%, it becomes difficult to obtain the effect of improving the meltability, and when it exceeds 45%, the chemical durability tends to deteriorate.

Al ₂ O ₃ is a component that improves chemical durability. The content of Al ₂ O ₃ is 0 to 10%, preferably 1 to 8%. When the content of Al ₂ O ₃ is more than 10%, the meltability tends to deteriorate. Incidentally, Al ₂ O ₃ is anorthite, gahnite, since a component of the crystal of spinel, if precipitating these crystals, it is preferable to positively added Al ₂ O _3.

  ZnO is a component that improves the meltability by lowering the melting temperature. The content of ZnO is preferably 0 to 10%, particularly 1 to 8%. When the content of ZnO exceeds 10%, chemical durability tends to deteriorate. In addition, since ZnO is a constituent component of garnite, it is preferable to positively add ZnO when the crystal is precipitated.

In addition to the above components, Li ₂ O, Na ₂ O, and K ₂ O are added up to 5% in total in order to improve the meltability of the glass or to lower the softening point to facilitate low-temperature firing. be able to. In addition, up to 5% of P ₂ O _{5 in} order to improve the meltability of the glass, and Ta ₂ O ₅ , TiO ₂ , Nb ₂ O ₅ , Gd ₂ O ₃ in order to improve the chemical durability of the glass. , La ₂ O ₃ may be added up to 15% each.

  The wavelength conversion member of the present invention is not particularly limited as long as the inorganic phosphor powder is dispersed in a glass matrix, but is composed of a sintered body of a mixed powder containing the inorganic phosphor powder and the glass powder. Inorganic phosphor powder is preferable because it can be easily and uniformly dispersed in the glass matrix.

The average particle diameter D50 of the glass powder is preferably from 0.1 to 100 [mu] m, particularly preferably from 1 to _{50 [} mu] m. When the average particle diameter D ₅₀ of the glass powder is too small, the greater the amount of generation of bubbles during the firing. If many bubbles are contained in the wavelength conversion member, light emission will be caused and the light emission efficiency tends to decrease. The preferred porosity is 2% or less, particularly 1% or less. On the other hand, when the average particle diameter D ₅₀ is too large, the inorganic phosphor powder is less likely to be uniformly dispersed in the wavelength conversion member, as a result, there is a tendency that emission efficiency of the wavelength conversion member is reduced.

  In the wavelength conversion member of the present invention, the glass matrix contains a precipitated crystal. The precipitated crystal varies depending on the type of the glass matrix, and examples thereof include wollastonite, anorthite, garnite, spinel and the like. The said precipitation crystal | crystallization can be produced | generated by heat-processing with respect to the glass which comprises a glass matrix in the temperature range of glass transition point-100 degreeC-glass transition point. For example, when the wavelength conversion member of the present invention is produced by firing a mixed powder containing glass powder and inorganic phosphor powder, glass powder that has been preliminarily subjected to heat treatment to precipitate crystals may be used as a raw material, After preparing a mixed powder containing glass powder and inorganic phosphor powder and producing a green compact by press molding or the like, heat treatment may be performed to precipitate crystals.

  The content of the precipitated crystals in the glass matrix is preferably 0.1 to 10% by mass, particularly 1 to 8% by mass. If the content of the precipitated crystals is less than 0.1% by mass, the effect of scattering the excitation light is difficult to obtain, and the light distribution characteristics tend to be inferior. On the other hand, when the content of the precipitated crystal exceeds 10% by mass, the scattering loss increases and the emission intensity tends to decrease.

  The size of the precipitated crystal is preferably 1 to 30 μm, particularly 10 to 20 μm in major axis. If the crystal size is longer and less than 1 μm, it is difficult to obtain the effect of scattering excitation light, and the light distribution characteristics tend to be inferior. On the other hand, if the size of the precipitated crystal exceeds 30 μm, the scattering loss tends to increase and the emission intensity tends to decrease.

  Examples of the inorganic phosphor powder include those that emit fluorescence having a wavelength longer than the wavelength of the excitation light when ultraviolet or visible excitation light is incident. For example, when an inorganic phosphor powder that emits complementary fluorescence to the hue of excitation light when incident excitation light consisting of visible light is incident, white light can be easily obtained by mixing the transmitted excitation light and fluorescence. A white LED can be manufactured. In particular, it is preferable that excitation light composed of visible light is light having a central wavelength of 430 to 490 nm and fluorescence is light having a central wavelength of 530 to 590 nm because white light can be easily obtained.

  The inorganic phosphor powder usable in the present invention is not particularly limited as long as it is generally available on the market. Examples thereof include garnets such as YAG, and other oxides, nitrides, oxynitrides, sulfides, oxysulfides, rare earth sulfides, aluminate chlorides, halophosphates, and the like.

  Among the inorganic phosphor powders, those having an excitation band at a wavelength of 300 to 500 nm and an emission peak at a wavelength of 380 to 780 nm, particularly blue (wavelength 440 to 480 nm), green (wavelength 500 to 540 nm), yellow (wavelength 540) ˜595 nm) and red (wavelength of 600 to 700 nm) are preferably used.

Examples of inorganic phosphor powder that emits blue light when irradiated with ultraviolet to near-ultraviolet excitation light having a wavelength of 300 to 440 nm include Sr ₅ (PO ₄ ) ₃ Cl: Eu ²⁺ , (Sr, Ba) MgAl ₁₀ O ₁₇ : Eu ²⁺ , (Sr, Ba) ₃ MgSi ₂ O ₈ : Eu ^{2+ and the} like.

As inorganic phosphor powders that emit green fluorescence when irradiated with ultraviolet to near-ultraviolet excitation light having a wavelength of 300 to 440 nm, SrAl ₂ O ₄ : Eu ²⁺ , SrGa ₂ S ₄ : Eu ²⁺ , SrBaSiO ₄ : Eu ²⁺ , CdS : In, CaS: Ce ³⁺ , Y ₃ (Al, Gd) ₅ O ₁₂ : Ce ²⁺ , Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce ³⁺ , SrSiOn: Eu ²⁺ , ZnS: Al ³⁺ , Cu ⁺ , CaS: Sn ²⁺ , CaS: Sn ²⁺ , F, CaSO ₄ : Ce ³⁺ , Mn ²⁺ , LiAlO ₂ : Mn ²⁺ , BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , Mn ²⁺ , ZnS: Cu ⁺ , Cl ⁻ , Ca ₃ WO ₆ : U, ^{_{Ca 3 SiO 4 Cl 2: Eu}} 2+, Sr 0.2 Ba 0.7 Cl 1.1 Al 2 O 3.45: Ce 3+ ^{_{Mn 2+, Ba 2 MgSi 2 O}} 7: Eu 2+, Ba 2 SiO 4: Eu 2+, Ba 2 Li 2 Si 2 O 7: Eu 2+, ZnO: S, ZnO: Zn, Ca 2 Ba 3 (PO 4) 3 Cl: Eu ²⁺ , BaAl ₂ O ₄ : Eu ^{2+ and the} like.

Examples of inorganic phosphor powders that emit green fluorescence when irradiated with blue excitation light having a wavelength of 440 to 480 nm include SrAl ₂ O ₄ : Eu ²⁺ , SrGa ₂ S ₄ : Eu ²⁺ , SrBaSiO ₄ : Eu ²⁺ , CdS: In, CaS: Ce ³⁺ , Y ₃ (Al, Gd) ₅ O ₁₂ : Ce ²⁺ , Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce ³⁺ , SrSiOn: Eu ^{2+ and the} like.

Examples of inorganic phosphor powder that emits yellow fluorescence when irradiated with ultraviolet to near-ultraviolet excitation light having a wavelength of 300 to 440 nm include ZnS: Eu ²⁺ , Ba ₅ (PO ₄ ) ₃ Cl: U, Sr ₃ WO ₆ : U, CaGa ₂ S ₄ : Eu ²⁺ , SrSO ₄ : Eu ²⁺ , Mn ²⁺ , ZnS: P, ZnS: P ³⁻ , Cl ⁻ , ZnS: Mn ^{2+ and the} like can be mentioned.

As an inorganic phosphor powder that emits yellow fluorescence when irradiated with blue excitation light having a wavelength of 440 to 480 nm, Y ₃ (Al, Gd) ₅ O ₁₂ : Ce ²⁺ , Ba ₅ (PO ₄ ) ₃ Cl: U, CaGa ₂ S ₄ : Eu ²⁺ , Sr ₂ SiO ₄ : Eu ²⁺ .

Examples of the inorganic phosphor powder that emits red fluorescence when irradiated with ultraviolet to near-ultraviolet excitation light having a wavelength of 300 to 440 nm include CaS: Yb ²⁺ , Cl, Gd ₃ Ga ₄ O ₁₂ : Cr ³⁺ , CaGa ₂ S ₄ : Mn. ²⁺ , Na (Mg, Mn) ₂ LiSi ₄ O ₁₀ F ₂ : Mn, ZnS: Sn ²⁺ , Y ₃ Al ₅ O ₁₂ : Cr ³⁺ , SrB ₈ O ₁₃ : Sm ²⁺ , MgSr ₃ Si ₂ O ₈ : Eu ²⁺ , Mn ²⁺ , α-SrO · 3B ₂ O ₃ : Sm ²⁺ , ZnS—CdS, ZnSe: Cu ⁺ , Cl, ZnGa ₂ S ₄ : Mn ²⁺ , ZnO: Bi ³⁺ , BaS: Au, K, ZnS: Pb ²⁺ , ZnS: Sn ²⁺ , Li ⁺ , ZnS: Pb, Cu, CaTiO ₃ : Pr ³⁺ , CaTiO ₃ : Eu ³⁺ , Y ₂ O ₃ : Eu ³⁺ , ( Y, Gd) ₂ O ₃ : Eu ³⁺ , CaS: Pb ²⁺ , Mn ²⁺ , YPO ₄ : Eu ³⁺ , Ca ₂ MgSi ₂ O ₇ : Eu ²⁺ , Mn ²⁺ , Y (P, V) O ₄ : Eu ³⁺ , Y ₂ O ₂ S: Eu ³⁺ , SrAl ₄ O ₇ : Eu ³⁺ , CaYAlO ₄ : Eu ³⁺ , LaO ₂ S: Eu ³⁺ , LiW ₂ O ₈ : Eu ³⁺ , Sm ³⁺ , (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ , Mn ²⁺ , Ba ₃ MgSi ₂ O ₈ : Eu ²⁺ , Mn ^{2+ and the} like.

Examples of inorganic phosphor powders that emit red fluorescence when irradiated with blue excitation light having a wavelength of 440 to 480 nm include ZnS: Mn ²⁺ , Te ²⁺ , Mg ₂ TiO ₄ : Mn ⁴⁺ , K ₂ SiF ₆ : Mn ⁴⁺ , SrS: Eu ²⁺ , CaS: Eu ²⁺ , Na _1.23 K _0.42 Eu _0.12 TiSi ₄ O ₁₁ , Na _1.23 K _0.42 Eu _0.12 TiSi ₅ O ₁₃ : Eu ³⁺ , CdS: In, Te CaAlSiN ₃ : Eu ²⁺ , CaSiN ₃ : Eu ²⁺ , (Ca, Sr) ₂ Si ₅ N ₈ : Eu ²⁺ , Eu ₂ W ₂ O _{7 and the} like.

  A plurality of inorganic phosphor powders may be mixed and used in accordance with the wavelength range of excitation light or light emission. For example, when white light is obtained by irradiation with ultraviolet excitation light, inorganic phosphor powders emitting blue, green, yellow, and red fluorescence may be mixed and used.

  The glass used as the glass matrix of the wavelength conversion member usually has a refractive index (nd) of about 1.5 to 2.0, whereas the inorganic phosphor powder is also wide as about 1.5 to 2.4. Has a refractive index. The combination of glass and inorganic phosphor powder has various possibilities, but particularly when the refractive index difference between glass and inorganic phosphor powder is small, scattering at the interface between the two becomes small. As a result, the linear component of the excitation light increases, and the light distribution characteristics are likely to deteriorate. Therefore, it can be said that the wavelength conversion member of the present invention is particularly effective when the difference in refractive index between the glass and the inorganic phosphor powder is small (for example, less than 0.05).

  The content of the inorganic phosphor powder in the wavelength conversion member is preferably 1 to 30% by mass, particularly preferably 2 to 20% by mass. When the content of the inorganic phosphor powder is less than 1% by mass, the light emission intensity becomes insufficient and it becomes difficult to obtain white illumination. On the other hand, when the content of the inorganic phosphor powder is more than 30% by mass, the excitation light is not sufficiently applied to the entire inorganic phosphor powder, and the emission intensity tends to decrease. In addition, pores are easily generated, and it is difficult to obtain a dense structure. If pores are present in the wavelength conversion member, moisture and the like are liable to enter the interior, which may reduce chemical durability.

  Moreover, the wavelength conversion member of this invention can add the ceramic powder which has translucency, such as low temperature type | mold quartz, low temperature type cristobalite, corundum, garnet, tetragonal zirconia, garnite, and cordierite. When the wavelength conversion member contains these ceramic powders, the effect of scattering the excitation light is further increased, and a wavelength conversion member having excellent light distribution characteristics is easily obtained. In order to enhance the scattering effect of excitation light, it is preferable to combine them so that the difference in refractive index between glass and ceramic powder becomes large. Specifically, the difference in refractive index between glass and ceramic powder is preferably 0.05 or more, particularly preferably 0.1 or more.

The average particle diameter _{D 50} of the ceramic powder is 1 to 30 [mu] m, it is particularly preferably 2 to 5 [mu] m. The average particle diameter D ₅₀ of the ceramic powder is difficult to obtain the effect of scattering the excitation light is less than 1 [mu] m, there tends to be inferior in light distribution characteristics. On the other hand, when the average particle diameter D ₅₀ of the ceramic powder is more than 30 [mu] m, scattering loss is increased emission intensity tends to decrease.

  The content of the ceramic powder in the wavelength conversion member is preferably 0.1 to 10% by mass, particularly 1 to 8% by mass. When the content of the ceramic powder is less than 0.1% by mass, the above effect is hardly obtained. On the other hand, when the content of the ceramic powder is more than 10% by mass, the scattering loss tends to increase and the emission intensity tends to decrease.

  The wavelength conversion member of the present invention preferably has a parallel ray (linear) transmittance of 5% or less, particularly 3% or less. Moreover, it is preferable that haze is 90% or more, especially 95% or more. When the parallel light transmittance exceeds 5% or the haze is less than 90%, the straight component of the excitation light tends to be excessive, and the light distribution characteristics of the semiconductor light emitting element device tend to be inferior.

  The wavelength conversion member of the present invention is, for example, preformed mixed powder containing inorganic phosphor powder and glass powder, and sintered at a predetermined temperature to obtain a sintered body, and then, if necessary, grinding, polishing, repressing, etc. It can produce by processing by.

  The preforming method is not particularly limited, and methods such as a press molding method, an injection molding method, a sheet molding method, and an extrusion molding method can be employed.

  The firing temperature of the mixed powder of glass powder and inorganic phosphor powder is preferably not less than the softening point of the glass powder, particularly not less than the softening point + 50 ° C. When the firing temperature is lower than the softening point of the glass powder, pores remain and the luminous efficiency tends to decrease. On the other hand, although an upper limit is not specifically limited, It is preferable that it is below the softening point of glass powder +100 degreeC. When the firing temperature is higher than the softening point of the glass powder + 100 ° C., the reaction between the glass powder and the inorganic phosphor powder proceeds, and the inorganic phosphor powder partially disappears and the emission intensity tends to decrease.

  The wavelength conversion member of the present invention can be used as a semiconductor light emitting device by combining with a semiconductor light emitting device such as an LED chip that is an excitation light source. The wavelength conversion member of the present invention may be directly adhered on a semiconductor light emitting element such as an LED chip, or may be adhered on a box surrounding the semiconductor light emitting element. Further, by installing a plurality of LED chips below the wavelength conversion member of the plate-like body, it can be used as a surface emitting device having a light emitting function and a diffusing function.

  EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited to these Examples.

  Table 1 shows Examples (No. 1 to 4) and Comparative Example (No. 5).

First, glass raw materials were weighed and mixed so as to have the glass composition shown in the table, and this mixture was melted in a platinum crucible at 900 to 1400 ° C. for 1 hour to be vitrified. Molding the molten glass into a film, and the obtained film-like glass was pulverized by a ball mill and then classified through a sieve of 325 mesh, average particle diameter D ₅₀ was obtained glass powder 30 [mu] m.

  Next, the inorganic phosphor powder and ceramic powder shown in Table 1 were mixed with the glass powder, and pressure-molded using a mold to prepare a button-shaped preform having a diameter of 1 cm. This preform was fired at the firing temperature shown in Table 1 to obtain a sintered body. Sample No. About 1-4, it heat-processed at the temperature shown in Table 1 before baking, and the crystal | crystallization was deposited in the glass matrix. The sintered body was polished and processed into a diameter of 8 mm and a thickness of 0.3 mm. About the obtained wavelength conversion member, the parallel light transmittance, haze, and light distribution characteristic were measured. The results are shown in Table 1.

  Precipitated crystal seeds were identified by powder X-ray diffraction. The amount of precipitated crystals was calculated from the peak intensity of the obtained X-ray diffraction chart.

  The parallel light transmittance and haze were measured according to JIS K7105.

  The light distribution characteristic is “◯” when the wavelength conversion member is irradiated with a blue LED, and the transmitted light is visually observed from angles of 0 ° and 60 ° with respect to the optical axis. The case where a deviation in chromaticity was recognized was evaluated as “x”.

  As is apparent from Table 1, sample No. which is an example of the present invention. The wavelength conversion members 1 to 4 had good light distribution characteristics because the parallel light transmittance was as small as 2.0% or less and the haze was as large as 97.4% or more. On the other hand, sample No. which is a comparative example. The wavelength conversion member No. 1 had inferior light distribution characteristics because the parallel light transmittance was as large as 11.0% and the haze was as small as 82.8% or more.

Claims (7)

  A wavelength conversion member formed by dispersing inorganic phosphor powder in a glass matrix, wherein crystals are precipitated in a part of the glass matrix.   The wavelength conversion member according to claim 1, wherein a difference in refractive index between the glass matrix and the precipitated crystal is 0.05 or more.   The wavelength conversion member according to claim 1 or 2, wherein the precipitated crystal is at least one selected from wollastonite, anorthite, garnite, and spinel.   The wavelength conversion member according to any one of claims 1 to 3, wherein the parallel light transmittance measured in accordance with JIS K7105 is 5% or less and the haze is 90% or more.   The wavelength conversion member according to any one of claims 1 to 4, comprising 0.1 to 10% by mass of ceramic powder.   The inorganic phosphor powder is at least one selected from oxide, nitride, oxynitride, sulfide, oxysulfide, rare earth sulfide, aluminate chloride, and halophosphate chloride The wavelength conversion member according to claim 1.   A semiconductor light-emitting element device using the wavelength conversion member according to claim 1.