JP6168284B2 - Wavelength conversion material, wavelength conversion member, and light emitting device - Google Patents

Description

  The present invention relates to a wavelength conversion material for producing a wavelength conversion member that converts the wavelength of light emitted from a light emitting diode (LED) or a laser diode (LD) to another wavelength. .

  In recent years, attention has been focused on light sources using LEDs and LDs as next-generation light sources that replace fluorescent lamps and incandescent lamps. As an example of such a next-generation light source, for example, Patent Document 1 discloses a light source in which a wavelength conversion member that absorbs part of light from an LED and converts it into yellow light is disposed on an LED that emits blue light. Is disclosed. This light source emits white light which is a combined light of blue light emitted from the LED and yellow light emitted from the wavelength conversion member.

  As the wavelength conversion member, a material in which an inorganic phosphor powder is dispersed in a resin matrix has been conventionally used. However, when the wavelength conversion member is used, there is a problem that the resin is deteriorated by the light from the LED and the luminance of the light source tends to be lowered. In particular, there is a problem that the resin deteriorates due to heat generated by the LED or high-energy short wavelength (blue to ultraviolet) light, causing discoloration or deformation.

  Therefore, a wavelength conversion member made of a completely inorganic solid in which an inorganic phosphor powder is dispersed and fixed in a glass matrix instead of a resin has been proposed (for example, see Patent Document 2). The wavelength conversion member has a feature that glass, which is a dispersion medium of inorganic phosphor powder, is not easily deteriorated by the heat or irradiation light of the LED chip, and problems such as discoloration and deformation hardly occur.

JP 2000-208815 A JP 2003-258308 A

  Since the wavelength conversion member is composed of a sintered body of glass powder and inorganic phosphor powder, there are grain boundaries and bubbles at the interface between the glass powder and inorganic phosphor powder. Due to the grain boundaries and bubbles, the internal scattering increases, the excitation light hits the inorganic phosphor powder more frequently, and the emission intensity increases.

  However, for example, when the difference in refractive index between the glass matrix and the inorganic phosphor powder is small, light scattering at the interface between the two is reduced. If the excitation light is not sufficiently diffused and the straight component increases, the frequency at which the excitation light hits the inorganic phosphor powder decreases, and the fluorescence intensity tends to decrease. Further, the light emitted from the wavelength conversion member tends to be inhomogeneous.

  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, but the chromaticity falls outside the desired range. Another problem will occur.

  In view of the above, an object of the present invention is to provide a wavelength conversion material for producing a wavelength conversion member capable of obtaining light with uniform and high emission intensity while maintaining a desired chromaticity range. .

  The wavelength conversion material of the present invention is characterized by containing two or more kinds of glass powders having different refractive indexes and an inorganic phosphor powder.

  As described above, in the wavelength conversion member in which the inorganic phosphor powder is dispersed in the glass matrix, if there is a large amount of the linear component of the excitation light, the frequency of the excitation light hitting the inorganic phosphor powder decreases, and the fluorescence intensity decreases. To do. Further, the light emitted from the wavelength conversion member is not uniform, and the chromaticity varies depending on the emission angle. Therefore, by using a wavelength conversion material containing two or more types of glass powders having different refractive indexes and inorganic phosphor powders, a wavelength conversion member in which regions having different refractive indexes are densely formed in a glass matrix is produced. It becomes possible to do. The wavelength conversion member has a large scattering effect of excitation light, and can emit light with uniform and high emission intensity.

  In addition, it is possible to improve the light diffusibility of the wavelength conversion member by blending a light diffusing material such as a filler into the wavelength conversion material, but if the content of the light diffusing material is too large, the glass during firing There are problems that the softening flow of the powder is hindered and the light scattering loss increases. Therefore, the amount of the light diffusing material in the wavelength conversion material cannot be increased too much. On the other hand, in the present invention, each glass powder to be blended can be sufficiently softened and flowed by appropriately adjusting the firing temperature, so that a desired amount of light scattering can be obtained, and the light scattering as described above. There is almost no loss problem.

  It is preferable that the refractive index difference between each glass powder is 0.001-1.

  It is preferable that the difference of the softening point between each glass powder is 150 degrees C or less.

Glass powder is SiO ₂ —B ₂ O ₃ —RO (R is Mg, Ca, Sr or Ba) glass, SiO ₂ —B ₂ O ₃ —R ′ ₂ O (R ′ is Li, Na or Ka) It is preferably made of glass or SiO ₂ —B ₂ O ₃ —RO—R ′ ₂ O-based glass.

  Inorganic phosphor powder is nitride phosphor powder, oxynitride phosphor powder, oxide phosphor powder, sulfide phosphor powder, oxysulfide phosphor powder, halide phosphor powder and aluminate phosphor powder It is preferable that it is 1 or more types selected from.

  It is preferable to contain 0.01-50 volume% of inorganic fluorescent substance powder.

  The wavelength conversion member of the present invention is obtained by firing any one of the wavelength conversion materials.

  The wavelength conversion member of the present invention is a wavelength conversion member in which inorganic phosphor powder is dispersed in a glass matrix, and the glass matrix is composed of two or more types of glass powders fused to each other and having different refractive indexes. It is characterized by.

  The light-emitting device of the present invention includes a wavelength conversion member and a light source that irradiates the wavelength conversion member with excitation light.

  The method for producing a wavelength conversion member of the present invention is a method for producing a wavelength conversion member comprising a step of firing any one of the wavelength conversion materials, wherein the firing temperature has the highest softening point of each glass powder. It is characterized by being above the softening point of the glass powder.

  ADVANTAGE OF THE INVENTION According to this invention, the wavelength conversion material for producing the wavelength conversion member which can obtain the light of uniform and high light emission intensity, maintaining a desired chromaticity range can be provided.

It is a schematic diagram which shows one Embodiment of the light-emitting device of this invention.

  The wavelength conversion material of the present invention is characterized by containing two or more kinds of glass powders having different refractive indexes and an inorganic phosphor powder.

  If the refractive index difference between the glass powders is too small, it becomes difficult to obtain sufficient light scattering properties. On the other hand, if the refractive index difference is too large, the excitation light is excessively scattered, resulting in a scattering loss and conversely, the light emission efficiency tends to decrease. In view of the above, the refractive index difference between the glass powders is preferably 0.001-1, more preferably 0.01-0.5.

  The difference in softening point between the glass powders is preferably 150 ° C. or less, more preferably 100 ° C. or less, and still more preferably 60 ° C. or less. If the difference between the softening points is too large, the glass powder having a low softening point during firing tends to cause crystals, foaming, etc., and the transmittance tends to decrease. As a result, the light emission intensity of the obtained wavelength conversion member tends to decrease.

  The glass powder has a role as a medium for stably holding the inorganic phosphor powder in the wavelength conversion member. Here, since the reactivity with the inorganic phosphor powder during firing varies depending on the composition of the glass powder, it is preferable to select a glass composition suitable for the inorganic phosphor powder to be used.

As the composition of the glass powder, for _{example, SiO 2, B 2 O 3} , P 2 O 5, Bi 2 O 3 and any one or more of TeO ₂ which contains 10 to 99 mol% are preferred. Specifically, SiO ₂ —B ₂ O ₃ —RO (R is Mg, Ca, Sr or Ba) -based glass, SiO ₂ —B ₂ O ₃ —R ′ ₂ O (R ′ is Li, Na or Ka). Glass, SiO ₂ —B ₂ O ₃ —RO—R ′ ₂ O glass, SiO ₂ —B ₂ O ₃ —ZnO glass, SnO—P ₂ O ₅ glass, TeO ₂ glass, Bi ₂ O ₃ System glass and the like.

The SiO ₂ -B ₂ O ₃ -RO based glass, for example, in _{mol%, SiO 2 30~80%, B} 2 O 3 1~40%, Al 2 O 3 0~20%, MgO 0~10% , CaO 0~30%, SrO 0~20% , BaO 0~40%, MgO + CaO + SrO + BaO 0~45%, Li 2 O 0~20%, Na 2 O 0~20%, K 2 O 0~20%, Li Those containing ₂ O + Na ₂ O + K ₂ O 0-20% and ZnO 0-20% are preferred. The reason for limiting the glass composition in this way will be described below.

SiO ₂ is a component that forms a glass network. The content of SiO ₂ is preferably 30 to 80%, more preferably 40 to 60%. When the content of SiO ₂ is too small, chemical durability tends to decrease. On the other hand, if the content of SiO ₂ is too large, the softening point becomes high, so that high-temperature firing is necessary for sufficient sintering. As a result, the inorganic phosphor powder tends to deteriorate during firing.

B ₂ O ₃ is a component having a great effect of improving the meltability by lowering the melting temperature. Further, it becomes likely to undergo phase separation by the inclusion of B ₂ O _3, an effect of improving a light diffusing property. The content of B ₂ O ₃ is preferably 1 to 40%, more preferably 5 to 30%. If the content of B ₂ O ₃ is too small, the effect is difficult to obtain. On the other hand, when the content of B ₂ O ₃ is too large, chemical durability tends to decrease.

Al ₂ O ₃ is a component that improves chemical durability. The content of Al ₂ O ₃ is preferably 0 to 20%, more preferably 1 to 18%. When the content of Al ₂ O ₃ is too large, there is a tendency that the melting is lowered.

  MgO, CaO, SrO and BaO are components that improve the meltability by lowering the melting temperature. It also has the effect of promoting phase separation. BaO also has an effect of suppressing the reaction with the inorganic phosphor powder. When there is too much content of these components, it exists in the tendency for chemical durability to fall. Further, the phase separation property becomes too large, and the phase separation state tends to fluctuate greatly even with a small change in the heat treatment temperature. As a result, the light diffusibility between lots of the obtained wavelength conversion member tends to vary.

  Preferred ranges for these components are as follows. The content of MgO is preferably 0 to 10%, more preferably 0 to 5%. The content of CaO is preferably 0 to 30%, more preferably 0 to 20%. The content of SrO is preferably 0 to 20%, more preferably 0 to 10%. The BaO content is preferably 0 to 40%, more preferably 0 to 30%. The total amount of MgO, CaO, SrO and BaO is preferably 0 to 45%, more preferably 2 to 35%.

Li ₂ O, Na ₂ O and K ₂ O are components that lower the softening point and promote phase separation. Among these, Li ₂ O has a remarkable effect. The content of these components is preferably 0 to 20%, more preferably 0.1 to 10%. When there is too much content of these components, chemical durability will fall easily. Also, the phase separation tends to be too large.

The total amount of Li ₂ O, Na ₂ O and K ₂ O is preferably 0 to 20%, more preferably 0.1 to 17%, and further preferably 1 to 16%.

  ZnO is a component that significantly promotes phase separation and lowers the melting temperature to improve the meltability. The content of ZnO is preferably 0 to 20%, more preferably 0.1 to 10%. When there is too much content of ZnO, chemical durability will fall easily. Also, the phase separation tends to be too large.

In addition to the above components, Ta ₂ O ₅ , TiO ₂ , Nb ₂ O ₅ , Gd ₂ O ₃ , La ₂ O ₃ , Y ₂ O ₃ , CeO ₂ , Sb are used for the purpose of improving chemical durability. ₂ O ₃ , SnO ₂ , Bi ₂ O ₃ or ZrO ₂ may be contained up to 15% each.

The _SnO-P 2 _{O 5} based glass, for example, in _{mol%, SnO 35~80%, P 2} O 5 5~40%, those containing 2 O 3 0~30% _B is preferred. The reason for limiting the glass composition in this way will be described below.

  SnO is a component that forms a glass network and lowers the softening point. The content of SnO is preferably 35 to 80%, more preferably 45 to 75%. When there is too little content of SnO, there exists a tendency for a softening point to become high or for a weather resistance to fall. On the other hand, when there is too much content of SnO, the devitrification thing resulting from Sn will precipitate and it will exist in the tendency for the transmittance | permeability to fall, As a result, the emitted light intensity of a wavelength conversion member will fall easily. Moreover, it becomes difficult to vitrify.

P ₂ O ₅ is a component that forms a glass network. The content of P ₂ O ₅ is preferably 5 to 40%, more preferably 10 to 30%. When the content of P ₂ O ₅ is too small, it is difficult to vitrify. On the other hand, when the content of P ₂ O ₅ is too large, or higher the softening point tends to weather resistance is remarkably lowered.

B ₂ O ₃ is a component that improves weather resistance and promotes phase separation. It also has the effect of stabilizing the glass. The content of B ₂ O ₃ is preferably 0 to 30%, more preferably 1 to 25%. If the B ₂ O ₃ content is too large, the weather resistance tends to lower. Also, the softening point tends to be too high.

In addition to the above components, the total amount of CaO, MgO, SrO or BaO is up to 5%, Li ₂ O, Na _{2 in} order to improve the meltability or lower the softening point to facilitate low temperature firing. O or K ₂ O can be contained up to 5% in total. In addition, for the purpose of improving chemical durability, Al ₂ O ₃ , ZrO, ZnO, Ta ₂ O ₅ , TiO ₂ , Nb ₂ O ₅ , Gd ₂ O ₃ , Bi ₂ O ₃ , TeO ₂ or Each of La ₂ O ₃ may be contained up to 15%.

Examples of the SiO ₂ —B ₂ O ₃ —R ′ ₂ O glass include mol%, SiO ₂ 30 to 80%, B ₂ O _{3 1 to} 55%, Li ₂ O 0 to 20%, and Na ₂ O. _{0~25%, K 2 O 0~25%} , Li 2 O + Na 2 O + K 2 O 5~35%, Al 2 O 3 0~10%, those containing 0% ZnO preferred.

In addition to the above components, MgO, CaO, SrO and BaO can be contained in a total amount of up to 5% in order to improve the meltability. Besides, P ₂ O ₅ is increased to 5% for improving the meltability, and Ta ₂ O ₅ , TiO ₂ , Nb ₂ O ₅ , Gd ₂ O ₃ or La ₂ O for improving the chemical durability. ₃ may be contained up to 15% each.

As SiO ₂ —B ₂ O ₃ —ZnO-based glass, for example, mol%, SiO ₂ 5-50%, B ₂ O ₃ 15-55%, ZnO 30-80%, Li ₂ O 0-20%, _{Na 2 O 0~20%, K 2} O 0~20%, 0~10% MgO, CaO 0~10%, SrO 0~10%, those preferably contain 0% BaO.

In addition to the above components, in order to improve chemical durability, Al ₂ O ₃ is added up to 5%, Ta ₂ O ₅ , TiO ₂ , Nb ₂ O ₅ , Gd ₂ O ₃ or La ₂ O ₃ is added to 15%. % May be included.

  The particle size of the glass powder is not particularly limited. For example, the maximum particle size Dmax is 200 μm or less (especially 150 μm or less, more preferably 105 μm or less), and the average particle size D50 is 0.1 μm or more (particularly 1 μm or more, further 2 μm or more). ) Is preferable. When the maximum particle diameter Dmax of the glass powder is too large, the excitation light is hardly scattered in the obtained wavelength conversion member, and the light emission efficiency tends to be lowered. Moreover, when the average particle diameter D50 is too small, in the obtained wavelength conversion member, excitation light will be scattered excessively and luminous efficiency will fall easily.

  In the present invention, the maximum particle diameter Dmax and the average particle diameter D50 indicate values measured by a laser diffraction method.

  What is necessary is just to adjust suitably the mixing ratio of each glass powder so that a desired amount of light scattering may be obtained. When a large amount of light diffusion is required, the volume ratio of each glass powder may be adjusted to be approximately the same. For example, when mixing 2 types of glass powder, it is preferable that the mixing ratio (volume ratio) of each glass powder is 30-70: 70-30, and it is more preferable that it is 40-60: 60-40. preferable.

  The inorganic phosphor powder is not particularly limited as long as it is generally available on the market. For example, nitride phosphor powder, oxynitride phosphor powder, oxide phosphor powder (including garnet phosphor powder such as YAG phosphor powder), sulfide phosphor powder, oxysulfide phosphor powder, halogen Fluoride phosphor powder (halophosphate chloride, etc.) and aluminate phosphor powder. Of these inorganic phosphor powders, nitride phosphor powders, oxynitride phosphor powders and oxide phosphor powders are preferable because they have high heat resistance and are relatively unlikely to deteriorate during firing. The nitride phosphor powder and the oxynitride phosphor powder are characterized by converting near-ultraviolet to blue excitation light into a wide wavelength region from green to red and having a relatively high emission intensity. Therefore, the nitride phosphor powder and the oxynitride phosphor powder are particularly effective as inorganic phosphor powders used for the wavelength conversion member for white LED elements.

  Examples of the inorganic phosphor powder include 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) or red light (wavelength 600 to 700 nm).

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, 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⁺ , SrBaSiO ₄ : Eu ²⁺ , Y ₃ (Al, Gd) ₅ O ₁₂ : Ce ²⁺ , SrSiO _n : Eu ²⁺ , BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , 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⁺ , BaAl ₂ O ₄ : Eu ^{2+ and the} like.

As inorganic phosphor powders that emit green fluorescence when irradiated with blue excitation light having a wavelength of 440 to 480 nm, SrAl ₂ O ₄ : Eu ²⁺ , SrBaSiO ₄ : Eu ²⁺ , Y ₃ (Al, Gd) ₅ O ₁₂ : Ce ³⁺ , SrSiO _n : Eu ²⁺ , β-SiAlON: Eu ^{2+ and the} like.

Examples of the inorganic phosphor powder that emits yellow fluorescence when irradiated with excitation light having a wavelength of 300 to 440 nm include La ₃ Si ₆ N ₁₁ : Ce ³⁺ .

Examples of the inorganic phosphor powder that emits yellow fluorescence when irradiated with blue excitation light having a wavelength of 440 to 480 nm include Y ₃ (Al, Gd) ₅ O ₁₂ : Ce ³⁺ and Sr ₂ SiO ₄ : Eu ²⁺ .

Inorganic phosphor powders that emit red fluorescence when irradiated with ultraviolet to near-ultraviolet excitation light having a wavelength of 300 to 440 nm include CaGa ₂ S ₄ : Mn ²⁺ , MgSr ₃ Si ₂ O ₈ : Eu ²⁺ , Mn ²⁺ , Ca _{2. ^{MgSi 2 O 7: Eu 2+,}} Mn 2+ , and the like.

Inorganic phosphor powders that emit red fluorescence when irradiated with blue excitation light having a wavelength of 440 to 480 nm include CaAlSiN ₃ : Eu ²⁺ , CaSiN ₃ : Eu ²⁺ , (Ca, Sr) ₂ Si ₅ N ₈ : Eu ²⁺ , α-SiAlON: Eu ^{2+ and the} like can be mentioned.

  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.

  When the content of the inorganic phosphor powder in the wavelength conversion material is too large, sintering tends to be difficult and the porosity tends to increase. As a result, in the obtained wavelength conversion member, problems such as it becomes difficult for the excitation light to be efficiently irradiated onto the inorganic phosphor powder, and the mechanical strength tends to decrease. On the other hand, when there is too little content of inorganic fluorescent substance powder, it will become difficult to obtain desired luminescence intensity. From such a viewpoint, the content of the inorganic phosphor powder in the wavelength conversion material is in volume%, preferably 0.01 to 50%, more preferably 0.05 to 40%, and still more preferably 0.1 to 30. % Is adjusted.

  Note that the wavelength conversion member for the purpose of reflecting the fluorescence generated in the wavelength conversion member to the excitation light incident side and mainly taking out only the fluorescence to the outside is not limited to the above, and the emission intensity is maximized. Thus, the content of the inorganic phosphor powder can be increased (for example, 50% to 80%, and further 55 to 75%).

  A wavelength conversion member can be obtained by baking the wavelength conversion material of the present invention. It is preferable that a calcination temperature is more than the softening point of the glass powder which has the highest softening point among each glass powder. Thereby, the glass matrix which each glass powder fuse | melts mutually can be formed. On the other hand, if the firing temperature is too high, the inorganic phosphor powder elutes in the glass and the emission intensity decreases, or the components contained in the inorganic phosphor powder diffuse into the glass and the glass is colored. May decrease. Therefore, the firing temperature is preferably the softening point of the glass powder having the highest softening point + 150 ° C. or lower, and more preferably the softening point of the glass powder having the highest softening point + 100 ° C. or lower.

Firing is preferably performed in a reduced-pressure atmosphere. Specifically, the firing is preferably performed in an atmosphere of less than 1.013 × 10 ⁵ Pa, more preferably 1000 Pa or less, and even more preferably 400 Pa or less. Thereby, the amount of bubbles remaining in the wavelength conversion member can be reduced. As a result, the scattering factor in the wavelength conversion member can be reduced, and the luminous efficiency can be improved. Note that the entire firing process may be performed in a reduced-pressure atmosphere, or only the firing process is performed in a reduced-pressure atmosphere, and the temperature raising and lowering steps before and after the firing process are performed in an atmosphere other than the reduced-pressure atmosphere (for example, under atmospheric pressure). May be.

  The shape of the wavelength conversion member of the present invention is not particularly limited. For example, a plate shape, a column shape, a spherical shape, a hemispherical shape, a hemispherical dome shape, etc. It may be a film formed on the surface of the substrate.

  FIG. 1 shows an embodiment of a light emitting device of the present invention. As shown in FIG. 1, the light emitting device 1 includes a wavelength conversion member 2 and a light source 3. The light source 3 irradiates the wavelength conversion member 2 with excitation light. The excitation light incident on the wavelength conversion member 2 is converted into light having a different wavelength and is emitted from the side opposite to the light source 3. At this time, the combined light of the light after wavelength conversion and the excitation light transmitted without wavelength conversion may be emitted.

  Hereinafter, the present invention will be described in detail based on examples, but the present invention is not limited to these examples.

(1) Production of glass powder Table 1 shows the composition of the glass powder used in this example.

  First, the raw materials were prepared so as to have the composition shown in Table 1. The raw material was melted and vitrified in a platinum crucible at a temperature of 800 to 1500 ° C. for 1 to 2 hours, and the molten glass was cast between a pair of cooling rollers to form a film. The film-like glass was pulverized with a ball mill and classified to obtain glass powder having an average particle diameter D50 of 2.5 μm.

The density, softening point, and refractive index (nd) of each glass powder were measured using a sample obtained by forming molten glass into a block shape or a cylindrical shape according to each measurement and annealing. The density was determined by the Archimedes method. For the softening point, a fiber elongation method was used, and a temperature at which the viscosity was 10 ^7.6 dPa · s was adopted. The refractive index was indicated by a measured value at the d-line (wavelength: 587.6 nm) of a helium lamp using a refractometer (KPR-200 manufactured by Kalnew).

(2) Production of Wavelength Conversion Member Tables 2 to 5 show Examples (Sample Nos. 6 to 17) and Comparative Examples (Sample Nos. 1 to 5) of the present invention.

A predetermined amount of Y ₃ (Al, Gd) ₅ O ₁₂ : Ce ³⁺ (YAG) phosphor powder is mixed with one or two of the glass powders listed in Table 1 to obtain a wavelength conversion material. Obtained. The wavelength conversion material was pressure-molded with a mold to prepare a cylindrical preform with a diameter of 1 cm. A disk-shaped wavelength conversion member having a diameter of 8 mm and a thickness of 0.2 mm was obtained by processing a sintered body obtained by firing this preformed body at a temperature shown in the table. The total luminous flux value was calculated for the obtained wavelength conversion member. The results are shown in Tables 2-5.

  The total luminous flux value was measured as follows. A wavelength conversion member is placed on a light source having an excitation wavelength of 460 nm, the wavelength conversion member is irradiated with excitation light in an integrating sphere, and the energy distribution spectrum of light emitted from the upper surface of the wavelength conversion member is used using a general-purpose emission spectrum measurement device. Measured. The total luminous flux value was calculated by multiplying the obtained spectrum by the standard relative luminous sensitivity.

  As is clear from Tables 2 to 5, the wavelength conversion member produced using a mixture of two types of glass powders had a higher total luminous flux value than the wavelength conversion member produced using one type of glass powder. As is clear from the comparison between Tables 3 and 5, the total luminous flux value was higher when the volume ratio of the two types of glass powders was about the same.

  The wavelength conversion material of the present invention is suitable as a material for wavelength conversion members used for general illumination such as white LED, special illumination (for example, projector light source, automobile headlamp light source) and the like.

DESCRIPTION OF SYMBOLS 1 Light emitting device 2 Wavelength conversion member 3 Light source

Claims (9)

Two or more glass powder having a different refractive index, a wavelength converting material you containing an inorganic phosphor powder, glass _{powder, SiO 2 -B 2 O 3 -RO} (R is Mg, Ca, Sr Or Ba) based glass, SiO ₂ —B ₂ O ₃ —R ′ ₂ O (R ′ is Li, Na or Ka) based glass, or SiO ₂ —B ₂ O ₃ —RO—R ′ ₂ O based glass. And a difference in softening point between the glass powders is 150 ° C. or less .   The wavelength conversion material according to claim 1, wherein a difference in refractive index between the glass powders is 0.001 to 1. 3. The wavelength conversion material according to claim 1, comprising two kinds of glass powders, wherein a mixing ratio (volume ratio) of each glass powder is 30 to 70:70 to 30. 4. Inorganic phosphor powder is nitride phosphor powder, oxynitride phosphor powder, oxide phosphor powder, sulfide phosphor powder, oxysulfide phosphor powder, halide phosphor powder and aluminate phosphor powder wavelength converting material according to any one of claims 1 to 3, characterized in that at least one selected from the. Wavelength converting material according to any one of claims 1 to 4, characterized in that it contains 0.01 to 50% by volume of inorganic phosphor powder.   A wavelength conversion member obtained by firing the wavelength conversion material according to any one of claims 1 to 5. A wavelength conversion member inorganic phosphor powder is dispersed in a glass matrix, the glass matrix was fused together, is composed of two or more kinds of glass powders having different refractive index, glass powder, SiO _2- B ₂ O ₃ —RO (R is Mg, Ca, Sr or Ba) glass, SiO ₂ —B ₂ O ₃ —R ′ ₂ O (R ′ is Li, Na or Ka) glass, or SiO _{2 -B 2 O 3 -RO-R} ' consists ₂ O-based glass, the wavelength conversion member difference of the softening point, characterized in der Rukoto 0.99 ° C. or less between each glass powder. Wavelength conversion member according to claim 6 or 7, and, the light emitting device characterized by including a light source for irradiating excitation light wavelength conversion member. It is a manufacturing method of the wavelength conversion member including the process of baking the wavelength conversion material as described in any one of Claims 1-5 , Comprising: The glass powder which has the highest softening point among each glass powder in baking temperature A method for producing a wavelength conversion member, characterized by being at or above the softening point.