JP2011122067A - Wavelength conversion member and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wavelength conversion member in which inorganic phosphor powder is dispersed in a glass matrix, and which can efficiently transmit excitation light or emission light from the inorganic phosphor powder, and provides a high light-emitting efficiency. <P>SOLUTION: The wavelength conversion member in which inorganic phosphor powder is dispersed in a glass matrix has a difference in Vickers hardness (ΔHv(0.05)) between the inorganic phosphor powder and the glass of ≥300, and has surface roughness Ra of ≤0.1 μm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a wavelength conversion member used as a constituent member such as a white LED and a method for manufacturing the same.

  In recent years, white LEDs have been actively developed. 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.

  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.

  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. In addition, when a resin containing an inorganic phosphor powder is applied on the LED, the thickness is likely to vary, which causes a decrease in light distribution.

  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. For example, the light emission characteristics of a white LED hardly change even when exposed to a long high temperature environment (150 ° C., 600 hours) or a long time high temperature high humidity environment (2000 hours, temperature 85 ° C., humidity 85%). Moreover, there is almost no coloring or deterioration even when exposed to the ultraviolet rays of sunlight for a long time. Furthermore, since it is excellent in workability, it is possible to suppress a decrease in light distribution due to thickness variations.

JP 2005-11933 A Japanese Patent No. 4158012

  A wavelength conversion member made by dispersing inorganic phosphor powder in a glass matrix is superior in long-term stability compared to conventional products, but it has a light-receiving surface that receives excitation light and light emission from inorganic phosphor powder (or wavelength conversion is not performed). In the light emitting surface from which the transmitted light of the excitation light is emitted, light loss due to reflection and scattering occurs, so that the light emission efficiency is still insufficient.

  Therefore, the present invention is a wavelength conversion member in which inorganic phosphor powder is dispersed in a glass matrix, and can efficiently transmit excitation light and light emission of inorganic phosphor powder, thereby obtaining high light emission efficiency. It is an object to provide a wavelength conversion member that can be used.

  As a result of intensive studies, the inventors focused on the hardness difference between the glass matrix and the inorganic phosphor powder in the wavelength conversion member in which the inorganic phosphor powder is dispersed in the glass matrix, and limited the hardness difference to a specific range. In addition, the present inventors have found that the above problem can be solved by using a structure having a specific surface property, and propose the present invention.

  That is, the present invention is a wavelength conversion member in which the inorganic phosphor powder is dispersed in a glass matrix, the difference in Vickers hardness (ΔHv (0.05)) between the inorganic phosphor powder and the glass is 300 or more, In addition, the present invention relates to a wavelength conversion member having a surface roughness Ra of 0.1 μm or less.

  Generally, in order to obtain a white LED with high luminous efficiency, a light receiving surface that receives excitation light from a wavelength conversion member and a light emitting surface that emits light emitted from inorganic phosphor powder (or transmitted light of excitation light that has not been wavelength converted). It is desirable that the excitation light is efficiently incident by mirror polishing both of the light and the light emitted from the inorganic phosphor powder or a part of the excitation light is transmitted. However, when polishing composites containing different materials such as glass and inorganic phosphor powder, if the hardness of the two is significantly different, a flat polished surface cannot be obtained due to the difference in polishing rate, rather It was found that the unevenness tends to be more conspicuous (surface roughness Ra is increased) by polishing. And it discovered that the unevenness | corrugation formed in the surface of the wavelength conversion member in that way was the cause of luminous efficiency fall.

  Therefore, in the present invention, attention is paid to the Vickers hardness difference (ΔHv (0.05)) between the inorganic phosphor powder and the glass in the wavelength conversion member, and particularly when the Vickers hardness difference is as large as 300 or more, the surface roughness Ra is set to 0. By limiting the thickness to 1 μm or less, light loss due to reflection or scattering can be suppressed as much as possible on the light receiving surface and the light emitting surface, and the light emission efficiency can be improved.

  In the present invention, the surface roughness Ra is a value measured according to JIS B0601: 2001.

  2ndly, the wavelength conversion member of this invention consists of a sintered compact of the mixed powder containing inorganic fluorescent substance powder and glass powder, It is characterized by the above-mentioned.

  According to the said structure, it becomes easy to disperse | distribute inorganic fluorescent substance powder uniformly in a glass matrix, and it can be set as the wavelength conversion member with small color dispersion. In addition, a wavelength conversion member having a desired shape (for example, a plate-like body) can be easily processed with high accuracy.

  Thirdly, the wavelength conversion member of the present invention is a plate-like body.

  Fourth, the wavelength conversion member of the present invention has a thickness of 0.05 to 1 mm.

  Fifth, the wavelength conversion member of the present invention is made of an inorganic phosphor powder having a garnet type, oxide, nitride, oxynitride, sulfide, oxysulfide, rare earth sulfide, aluminate chloride, and halophosphate. It is characterized by being at least one selected from a product.

  Sixth, the wavelength conversion member of the present invention is characterized in that the glass has a softening point of 850 ° C. or lower.

  Seventh, the present invention preliminarily molds a mixed powder containing inorganic phosphor powder and glass powder, and obtains a sintered body by firing at a temperature equal to or higher than the softening point of the glass powder, and diamond abrasive grains. It is related with the manufacturing method of the wavelength conversion member including the process of grind | polishing the surface of a sintered compact using the grinding | polishing slurry containing.

  Abrasive grains, such as cerium oxide, which have been generally used for the surface of a wavelength conversion member having a very large Vickers hardness difference (ΔHv (0.05)) of 300 or more between inorganic phosphor powder and glass. When used for polishing, the surface roughness Ra tends to be larger than 0.1 μm (particularly 0.2 μm or more) due to the difference in polishing rate between the inorganic phosphor powder and the glass. In the white LED using the wavelength conversion member obtained in this way, excitation light from the LED chip and light emission from the inorganic phosphor powder are likely to be scattered on the surface of the member, and the light emission efficiency is inferior. On the other hand, according to the production method of the present invention, even when the Vickers hardness difference (ΔHv (0.05)) between the inorganic phosphor powder and the glass is as large as 300 or more, diamond abrasive grains are used for polishing the surface of the member. Therefore, the polishing rate difference due to the Vickers hardness difference can be minimized. Therefore, the inorganic phosphor powder and the glass can be uniformly polished, and a very small surface roughness Ra of 0.1 μm or less can be easily achieved. As a result, it is possible to obtain a wavelength conversion member having excellent luminous efficiency.

  The wavelength conversion member of the present invention has a surface roughness Ra as small as 0.1 μm or less, even though the Vickers hardness difference (ΔHv (0.05)) between the inorganic phosphor powder and the glass matrix is as large as 300 or more. Therefore, when used for a white LED, the luminous efficiency is excellent. When the surface roughness Ra is larger than 0.1 μm, the transmittance of the excitation light decreases due to light scattering on the surface of the wavelength conversion member, and the amount of excitation light irradiated to the inorganic phosphor powder also decreases. The amount of emitted light decreases. In addition, light emitted from the inorganic phosphor powder is also scattered on the light emitting surface of the wavelength conversion member, causing loss. As a result, the light emission efficiency of the wavelength conversion member decreases. The surface roughness Ra is preferably 0.05 μm or less.

  In the present invention, if the difference in Vickers hardness (ΔHv (0.05)) between the inorganic phosphor powder and the glass matrix is 350 or more, particularly 400 or more, the effect of the present invention can be more easily enjoyed.

  Although the shape of the wavelength conversion member of the present invention is not particularly limited, for example, if it is a plate-like body, the surface roughness Ra is easily achieved because surface polishing is easy. When the wavelength conversion member is a plate-like body, the thickness is preferably 0.05 to 1 mm, particularly preferably 0.1 to 0.8 mm. When the thickness of the wavelength conversion member is less than 0.05 mm, the mechanical strength is inferior, and manufacture and processing become difficult. On the other hand, when the thickness of the wavelength conversion member exceeds 1 mm, the excitation light from the LED becomes difficult to transmit, and the light flux value tends to decrease.

  When the wavelength conversion member is a plate-like body, it is preferable that the surface roughness Ra of both surfaces is 0.1 μm or less because high luminous efficiency can be obtained.

  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 device 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. For example, a garnet system such as YAG (Hv (0.05) = 1100 to 1700), oxide (Hv (0.05) = 800 to 1600), nitride (Hv (0.05) = 1200 to 1800), Oxynitrides (Hv (0.05) = 1200-1800), sulfides (Hv (0.05) = 100-400), oxysulfides (Hv (0.05) = 100-400), rare earth sulfides (Hv (0.05) = 100 to 400), aluminate chloride (Hv (0.05) = 800 to 1500), halophosphate chloride (Hv (0.05) = 800 to 1500), etc. Is mentioned.

  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+ and the} like.

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 matrix in the present invention has a role as a medium for stably holding the inorganic phosphor powder. Moreover, since the color tone of the wavelength conversion member differs depending on the glass composition of the glass matrix and the reactivity with the inorganic phosphor powder varies, it is preferable to select the glass composition to be used in consideration of these conditions. Furthermore, it is also important to determine the addition amount of the inorganic phosphor powder suitable for the glass composition and the thickness of the wavelength conversion member. The glass is not particularly limited as long as it does not easily react with the inorganic phosphor powder, but glass made of glass having a softening point of 850 ° C. or lower, more preferably 800 ° C. or lower is preferably used. When the softening point of the glass is increased, the firing temperature is also increased. Therefore, the inorganic phosphor powder is deteriorated during firing, and it becomes difficult to obtain a wavelength conversion member having high luminous efficiency.

Examples of the glass include SiO ₂ —B ₂ O ₃ —RO-based glass (R represents Mg, Ca, Sr, Ba) (Hv (0.05) = 500 to 700), SiO ₂ —B ₂ O _3. —R ′ ₂ O-based glass (R ′ represents Li, Na, K) (Hv (0.05) = 500 to 700), SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ based glass (Hv (0 .05) = 500 to 700), SiO ₂ —B ₂ O ₃ —ZnO glass (Hv (0.05) = 500 to 700), ZnO—B ₂ O ₃ glass (Hv (0.05) = 400 ˜600), SnO—P ₂ O ₅ glass (Hv (0.05) = 200 to 400) can be used. What is necessary is just to select these glasses suitably according to the characteristic made into the objective. For example, when firing at a low temperature, a ZnO—B ₂ O ₃ system glass or SnO—P ₂ O ₅ system glass having a relatively low softening point may be selected, and when it is desired to improve the weather resistance of the wavelength conversion member, SiO ₂ —B ₂ O ₃ —RO glass, SiO ₂ —B ₂ O ₃ —R ′ ₂ O glass, SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ glass, SiO ₂ —B ₂ O ₃ — A ZnO-based glass may be selected.

When SiO ₂ —B ₂ O ₃ —RO-based glass is used, the mol% is SiO ₂ 30-80%, B ₂ O ₃ 1-30%, MgO 0-10%, CaO 0-30%, SrO 0 It is preferable to use a glass containing a composition of 20%, BaO 0-40%, MgO + CaO + SrO + BaO 5-45%, Al ₂ O ₃ 0-10%, ZnO 0-10%.

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 of the glass to facilitate firing at low temperatures. can do. 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.

When SiO ₂ —B ₂ O ₃ —R ′ ₂ O-based glass is used, it is mol%, SiO ₂ 30 to 80%, B ₂ O _{3 1 to} 55%, Li ₂ O 0 to 20%, Na ₂ O 0. It is preferable to use glass containing a composition of ˜25%, K ₂ O 0-25%, Li ₂ O + Na ₂ O + K ₂ O 5-35%, Al ₂ O ₃ 0-10%, ZnO 0-10%. .

In addition to the above components, MgO, CaO, SrO and BaO can be added up to 5% in total in order to improve the meltability of the glass. In addition, in order to improve the melting property of glass, P ₂ O ₅ is up to 5%, and in order to improve the chemical durability of glass, Ta ₂ O ₅ , TiO ₂ , Nb ₂ O ₅ , Gd ₂ O ₃ and La ₂ O ₃ may be added up to 15% each.

When SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ glass is used, the mol% is SiO ₂ 30 to 70%, B ₂ O ₃ 15 to 55%, Al ₂ O ₃ 15 to 55%, Li ₂ O. _{0~10%, Na 2 O 0~10%} , K 2 O 0~10%, 0~10% MgO, CaO 0~10%, SrO 0~10%, glass containing a composition of BaO 0% Is preferably used.

In addition to the above components, P ₂ O ₅ can be up to 5% in order to improve the meltability of the glass, and Ta ₂ O ₅ , TiO ₂ , Nb ₂ O ₅ , in order to improve the chemical durability of the glass, Gd ₂ O ₃ and La ₂ O ₃ may be added up to 15% each.

When SiO ₂ —B ₂ O ₃ —ZnO-based glass is used, the molar percentage is SiO ₂ 5-50%, B ₂ O ₃ 15-55%, ZnO 30-80%, Li ₂ O 0-10%, Na _{2 O 0~10%, K 2 O} 0~10%, 0~10% MgO, CaO 0~10%, SrO 0~10%, it is preferable to use a glass containing composition of BaO 0% .

In addition to the above components, Al ₂ O ₃ may be added up to 5% in order to improve the chemical durability of the glass, and Ta ₂ O ₅ and TiO _{2 in} order to improve the chemical durability of the glass. Nb ₂ O ₅ , Gd ₂ O ₃ , La ₂ O ₃ may be added up to 15% each.

When using a _ZnO-B 2 _{O 3} based glass, in _{mol%, 30~80% ZnO, B 2} O 3 20~70%, SiO 2 0~5%, Li 2 O 0~10%, Na 2 O 0 _{~10%, K 2 O 0~10%} , 0~10% MgO, CaO 0~10%, SrO 0~10%, it is preferable to use a glass containing composition of BaO 0%.

In addition to the above components, Al ₂ O ₃ may be added up to 5% in order to improve the chemical durability of the glass, and Ta ₂ O ₅ and TiO _{2 in} order to improve the chemical durability of the glass. Nb ₂ O ₅ , Gd ₂ O ₃ , La ₂ O ₃ may be added up to 15% each.

When using SnO—P ₂ O ₅ glass, it is mol%, SnO 35-80%, P ₂ O ₅ 5-40%, B ₂ O ₃ 0-30%, Al ₂ O ₃ 0-10%, SiO _{2 0~10%, Li 2 O 0~10} %, Na 2 O 0~10%, K 2 O 0~10%, 0~10% MgO, CaO 0~10%, SrO 0~10%, BaO 0 It is preferable to use a glass containing 10% to 10% composition.

In addition to the above components, ZnO, Ta ₂ O ₅ , TiO ₂ , Nb ₂ O ₅ , Gd ₂ O ₃ , and La ₂ O ₃ may be added up to a total amount of 10% in order to improve the weather resistance. .

In order to lower the softening point and stabilize the glass, it is preferable to set SnO / P ₂ O ₅ (molar ratio) in the range of 0.9 to 16. When SnO / P ₂ O ₅ is smaller than 0.9, the softening point is increased, making low-temperature firing difficult, and the inorganic phosphor powder tends to deteriorate. Further, the weather resistance tends to be remarkably lowered. On the other hand, when SnO / P ₂ O ₅ is larger than 16, devitrification bumps due to Sn are precipitated in the glass, and the transmittance of the glass tends to be lowered. As a result, the wavelength conversion member having high luminous efficiency. Is difficult to obtain. The preferable range of SnO / P ₂ O ₅ is 1.5 to 10, more preferably 2 to 5.

  The wavelength conversion member of the present invention is not particularly limited as long as the inorganic phosphor powder is dispersed in the 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 _{D 50} of the glass powder used in the present invention, 0.1 to 100 [mu] m, it is particularly preferably 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 is likely to be caused and light emission efficiency tends to be reduced. 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.

  The luminous efficiency (lm / W) of the wavelength conversion member varies depending on the type and content of the inorganic phosphor powder dispersed in the glass matrix and the thickness of the luminescent color conversion member. If you want to increase the luminous efficiency of the wavelength conversion member, adjust the thickness by reducing the thickness to increase the transmittance of excitation light or fluorescence, or increase the content of inorganic phosphor powder to increase the amount of light to be converted. That's fine. However, when the content of the inorganic phosphor powder is too large, it is difficult to obtain a dense structure and the porosity tends to increase. As a result, problems such as it becomes difficult for the excitation light to be efficiently applied to the inorganic phosphor powder, and the mechanical strength of the wavelength conversion member tends to decrease. On the other hand, when there is too little content of inorganic fluorescent substance powder, it becomes difficult to obtain sufficient light emission. Therefore, the content of the inorganic phosphor powder in the wavelength conversion member is preferably 0.01% to 30%, 0.05% to 20%, and particularly preferably 0.08% to 15% in mass%.

  The method for producing a wavelength conversion member of the present invention comprises a step of obtaining a sintered body by preforming a mixed powder containing an inorganic phosphor powder and a glass powder, and firing the mixture at a temperature equal to or higher than the softening point of the glass powder, and diamond. It includes a step of polishing the surface of the sintered body using a polishing slurry containing abrasive grains.

  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 temperature for firing the mixed powder of glass powder and inorganic phosphor powder is preferably in the range of 300 to 900 ° C., particularly 300 to 850 ° C., and within the softening point of glass powder within ± 50 ° C. When the firing temperature is higher than 900 ° C. or the softening point of glass powder + 50 ° C., the inorganic phosphor powder may be deteriorated, or the glass powder and the inorganic phosphor powder may react to significantly reduce the light emission efficiency. Further, when the firing temperature is lower than 300 ° C. or the softening point of glass powder −50 ° C., the porosity of the wavelength conversion member increases, light scattering tends to be strong, and as a result, the amount of transmitted light decreases and the luminous efficiency decreases. May decrease.

If the diameter of the diamond abrasive grains is too small, the polishing rate becomes insufficient and the productivity tends to be inferior. On the other hand, when the grain size of the diamond abrasive grains is too large, it becomes difficult to obtain a desired surface roughness Ra. A preferable range of the average particle diameter D ₅₀ of the diamond abrasive grains is 1 to 10 μm, particularly 2 to 3 μm.

  As the polishing surface plate, a surface plate having a cloth material woven with fibers on the surface, a composite surface plate of tin and resin, a urethane pad, or the like can be used.

  The polishing method is not particularly limited, and examples thereof include a method (fixed ring polishing method) in which one side of the wavelength conversion member is fixed on a polishing surface plate and polished on each side. Alternatively, a batch type polishing method may be used in which the wavelength conversion member is fixed to a fixing carrier and sandwiched between surface plates, and both surfaces are polished at once.

In addition, before polishing with diamond abrasive grains, it is preferable to perform rough polishing with loose abrasive grains such as alumina ceramic or silicon carbide. The count of free abrasive grains, # 1200 or more, more # 2000 or more, preferably a 10~20μm the average particle diameter _{D 50.} The surface roughness Ra of the wavelength conversion member after rough polishing is preferably 0.5 μm or less. Moreover, it is preferable that the thickness of the wavelength conversion member after rough polishing is +15 to +20 μm with respect to the target final product thickness. When the surface roughness Ra or the thickness of the wavelength conversion member after rough polishing exceeds the above range, the polishing time by the diamond abrasive grains is greatly increased and the productivity is deteriorated.

  According to the manufacturing method of the present invention, it is easy to make the thickness of the wavelength conversion member of the plate-like body constant, and the white LED device using the wavelength conversion member can easily obtain uniform white light. Further, since the balance between the excitation light intensity and the fluorescence intensity can be freely changed simply by changing the thickness of the wavelength conversion member, white light having a desired chromaticity and color temperature can be easily obtained.

  The wavelength conversion member of the present invention may be directly adhered on the LED chip, or may be adhered on a box surrounding the LED chip. In addition, by installing a plurality of LED chips below the wavelength conversion member of the plate-like body of the present invention, 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.

  Tables 1-3 show Examples (No. 1, 3, 5, 7, 9, 11, 13, 15) and Comparative Examples (No. 2, 4, 6, 8, 10, 12, 14, 16) of the present invention. ).

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 45 [mu] m. The softening point of the obtained glass powder was measured. The softening point was measured using a macro type parallax thermal analyzer, and the value of the fourth inflection point of the obtained graph was used as the softening point.

  Next, glass powder and inorganic phosphor powder were mixed so as to have a blending ratio shown in the table, and pressure-molded using a mold to produce a button-shaped preform having a diameter of 1 cm. This preform was fired at the firing temperature shown in the table to obtain a sintered body. The sintered body was subjected to rough grinding and polishing to a diameter of 8 mm and a thickness of 0.3 mm. Subsequently, double-side polishing was performed using a surface plate having a cloth material woven with diamond abrasive grains and fibers on the surface to obtain a wavelength conversion member. The sample of the comparative example was double-side polished using cerium oxide abrasive grains and a urethane pad. About the obtained wavelength conversion member, the Vickers hardness and luminous efficiency of the glass matrix and inorganic fluorescent substance powder were measured. The results are shown in Tables 1-3.

  The Vickers hardness measurement value (HV) was the average of the values measured for ten points on the same measurement sample surface. The load used for the measurement was 50 g.

  The light emission characteristics of the wavelength conversion member were evaluated as follows. Each sample was excited by a blue LED, and light emitted from the front of the sample was measured in an integrating sphere to obtain its emission spectrum. Luminous efficiency was calculated from the obtained spectrum.

  As is apparent from the table, the sample No. which is an example of the present invention. The wavelength conversion members 1, 3, 5, 7, 9, 11, 13, and 15 have a surface roughness Ra of 0.05 μm or less despite the Vickers hardness of 300 or more, corresponding to each example. Luminous efficiency was good compared with the comparative examples (sample No. 2, 4, 6, 8, 10, 11, 12, 14, 16).

Claims (7)

  A wavelength conversion member in which an inorganic phosphor powder is dispersed in a glass matrix, the Vickers hardness difference (ΔHv (0.05)) between the inorganic phosphor powder and the glass is 300 or more, and the surface roughness Ra is A wavelength conversion member characterized by being 0.1 μm or less.   The wavelength conversion member according to claim 1, comprising a sintered body of a mixed powder containing an inorganic phosphor powder and a glass powder.   The wavelength conversion member according to claim 1, wherein the wavelength conversion member is a plate-like body.   The wavelength conversion member according to claim 3, wherein the wavelength conversion member has a thickness of 0.05 to 1 mm.   The inorganic phosphor powder is at least one selected from garnet, oxide, nitride, oxynitride, sulfide, oxysulfide, rare earth sulfide, aluminate chloride and halophosphate chloride The wavelength conversion member according to any one of claims 1 to 4, wherein   The wavelength conversion member according to claim 1, wherein the glass has a softening point of 850 ° C. or less.   Pre-molding mixed powder containing inorganic phosphor powder and glass powder, sintering at a temperature equal to or higher than the softening point of glass powder, and sintering using polishing slurry containing diamond abrasive grains The manufacturing method of the wavelength conversion member including the process of grind | polishing the surface of a body.