JP7535233B2 - Wavelength conversion member and light-emitting device using same - Google Patents

Description

The present invention relates to a wavelength conversion member for converting the wavelength of light emitted by a light-emitting element such as a light-emitting diode (LED) or a laser diode (LD) to another wavelength.

In recent years, light sources using LEDs and LDs have been attracting attention as the next generation of light sources to replace fluorescent lamps and incandescent lamps, from the viewpoints of low power consumption, small size and light weight, and easy light intensity adjustment. 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 the light from the LED and converts it to yellow light is placed on an LED that emits blue light. This light source emits white light that is a composite light of the blue light emitted from the LED and the yellow light emitted from the wavelength conversion member.

Conventionally, wavelength conversion materials have been made by dispersing inorganic phosphors in a resin matrix. However, when such wavelength conversion materials are used, there is a problem that the resin deteriorates due to the light from the LED, which tends to reduce the brightness of the light source. In particular, there is a problem that the heat and high-energy short-wavelength (blue to ultraviolet) light emitted by the LED deteriorates the resin matrix, causing discoloration and deformation.

In response to this, a wavelength conversion material made of a completely inorganic solid has been proposed in which inorganic phosphors are dispersed and fixed in a glass matrix instead of a resin (see, for example, Patent Documents 2 and 3). The wavelength conversion material has the advantage that the glass base material is less likely to deteriorate due to the heat or irradiated light from the LED chip, and is less likely to cause problems such as discoloration or deformation.

However, the wavelength conversion members described in Patent Documents 2 and 3 have a problem in that the inorganic phosphor deteriorates due to firing during production, and brightness is easily deteriorated. In particular, for applications such as general lighting and special lighting, high color rendering is required, so it is necessary to use inorganic phosphors with relatively low heat resistance, such as red and green, and the deterioration of the inorganic phosphor tends to be significant. Therefore, a wavelength conversion member has been proposed in which the softening point of the glass powder is lowered by including an alkali metal oxide in the glass composition (see, for example, Patent Document 4). This wavelength conversion member can be manufactured by firing at a relatively low temperature, so the deterioration of the inorganic phosphor during firing can be suppressed.

JP 2000-208815 A JP 2003-258308 A Patent No. 4895541 JP 2007-302858 A

The wavelength conversion material described in Patent Document 4 has a problem in that the emission intensity is prone to decrease over time (temperature quenching). With the further increase in output of light sources such as LEDs and LDs in recent years, the decrease in emission intensity over time has become increasingly noticeable.

In view of the above, the present invention aims to provide a wavelength conversion material that exhibits minimal decrease in luminous intensity over time when irradiated with light from an LED or LD, and a light-emitting device using the same.

The wavelength conversion member of the present invention is a wavelength conversion member having an inorganic phosphor dispersed in a glass matrix, the glass matrix containing, in mole %, 30-85% SiO ₂ , 0-20% B ₂ O ₃ , 0-25% Al ₂ O ₃ , 0-3% Li ₂ O , 0-3% Na ₂ O , 0-3% K ₂ O , 0-3% Li ₂ O + Na ₂ O + K ₂ O , 0-35% MgO, 0-35% CaO, 0-35% SrO, 0-35% BaO, 0.1-45% MgO + CaO + SrO + BaO, and ZnO. The inorganic phosphor is at least one selected from the group consisting of oxide phosphors, nitride phosphors, oxynitride phosphors, chloride phosphors, oxychloride phosphors, halide phosphors, aluminate phosphors, and halophosphate chloride phosphors, where "○+○+..." indicates the total amount of the corresponding components.

The inventors have discovered that the decrease in the emission intensity over time in wavelength conversion materials is caused in particular by the alkali metal components contained in the glass composition. The mechanism is believed to be as follows.

When excitation light is irradiated onto a glass matrix containing an alkali metal element in its composition, the energy of the excitation light excites the electrons present in the outermost shell of the oxygen ions in the glass matrix, and they leave the oxygen ions. Some of them combine with alkali ions in the glass matrix to form color centers (where holes are formed after the alkali ions leave). Meanwhile, the holes generated by the electrons leaving move through the glass matrix, and some are captured by the holes formed after the alkali ions leave to form color centers. It is believed that these color centers formed in the glass matrix become sources of absorption of the excitation light and fluorescence, and the luminescence intensity of the wavelength conversion material decreases. Furthermore, the heat generated by the inorganic phosphor (heat generated due to wavelength conversion loss) tends to activate the movement of electrons, holes, and alkali ions in the glass matrix. This accelerates the formation of color centers, making it easier for the luminescence intensity to decrease.

In the wavelength conversion member of the present invention, the content of alkali metal components in the glass matrix is minimized as described above, thereby suppressing the generation of color centers. In addition, by minimizing the content of alkali metal components in the glass matrix, degradation of the glass matrix over time under high temperature and high humidity conditions can also be suppressed.

The glass matrix in the wavelength conversion member of the present invention contains alkaline earth oxides (MgO, CaO, SrO, BaO) as essential components. The alkaline earth oxides can lower the softening point of the glass matrix without affecting the decrease in luminescence intensity over time in the wavelength conversion member, as do alkali metal ions. This makes it possible to suppress the deterioration of the properties of the inorganic phosphor caused by firing during production.

In the wavelength conversion member of the present invention, the glass matrix preferably contains, in mol %, 30-85% SiO ₂ , 0-20% B ₂ O ₃ , 0-25% Al ₂ O ₃ , 0-3% Li ₂ O , 0-3% Na ₂ O , 0-3% K ₂ O , 0-3% Li ₂ O + Na ₂ O + K ₂ O , 0-35% MgO, 0-35% CaO, 0-35% SrO, 0-35% BaO, 0.1-45% MgO + CaO + SrO + BaO, and 0-less than 1.8% ZnO.

In the wavelength conversion member of the present invention, it is preferable that the softening point of the glass matrix is 600 to 1100°C.

The wavelength conversion member of the present invention preferably contains 0.01 to 70 mass% of inorganic phosphor.

The wavelength conversion member of the present invention is preferably made of a powder sintered body.

The light-emitting device of the present invention is characterized by comprising the above-mentioned wavelength conversion member and a light source that irradiates the wavelength conversion member with excitation light.

The vehicle lighting of the present invention is characterized by using the above-mentioned light-emitting device.

The vehicle lighting of the present invention is characterized by its use as a headlight.

When the wavelength conversion material of the present invention is irradiated with light from an LED or LD, the emission intensity does not decrease much over time. Therefore, a light-emitting device using the wavelength conversion material of the present invention has excellent long-term reliability and is suitable for use as an in-vehicle lighting device, particularly as an in-vehicle headlamp.

1 is a schematic side view of a light-emitting device according to one embodiment of the present invention;

The wavelength conversion member of the present invention is formed by dispersing an inorganic phosphor in a glass matrix. The glass matrix contains, in mole percent, 30-85% SiO ₂ , 0-20% B ₂ O ₃ , 0-25% Al ₂ O ₃ , 0-3% Li ₂ O , 0-3% Na ₂ O , 0-3% K ₂ O , 0-3% Li ₂ O + Na ₂ O + K ₂ O , 0-35% MgO , 0-35% CaO , 0-35% SrO , 0-35% BaO , 0.1-45% MgO + CaO + SrO + BaO , and 0-4% ZnO . The reason for limiting the glass composition range in this way will be explained below. In the following explanation, "%" means "mol %" unless otherwise specified.

_SiO2 is a component that forms a glass network. _{The SiO2} content is 30 to 85%, and preferably 35 to 80%. If the _SiO2 content is too low, the weather resistance and mechanical strength tend to decrease. On the other hand, if the _SiO2 content is too high, the sintering temperature becomes high, and the inorganic phosphor is easily deteriorated during the production of the wavelength conversion member.

B ₂ O ₃ is a component that lowers the melting temperature and significantly improves the melting property. The content of B ₂ O ₃ is 0 to 20%, and preferably 0.1 to 18%. If the content of B ₂ O ₃ is too high, the weather resistance is likely to decrease.

Al ₂ O ₃ is a component that improves weather resistance and mechanical strength. The content of Al ₂ O ₃ is 0 to 25%, and preferably 0.1 to 20%. If the content of Al ₂ O ₃ is too high, the melting property tends to decrease.

Li ₂ O, Na ₂ O and K ₂ O are components that lower the melting temperature to improve the melting property and lower the softening point. However, if the content of these components is too high, the weather resistance is likely to decrease, and the emission intensity is likely to decrease over time due to light irradiation from LED or LD. Therefore, the content of Li ₂ O + Na ₂ O + K ₂ O is 0 to 3%, preferably 0 to 2%. In addition, the content of each of the components Li ₂ O, Na ₂ O and K ₂ O is 0 to 3%, preferably 0 to 2%. When Li ₂ O, Na ₂ O and K ₂ O are contained, it is preferable to use two or more kinds, especially three kinds, mixed together. In this way, it is possible to suppress the decrease over time of the emission intensity due to light irradiation from LED or LD due to the mixed alkali effect.

MgO, CaO, SrO and BaO are components that lower the melting temperature, improve the melting property and lower the softening point. As mentioned above, unlike alkali metal components, these components do not affect the decrease in the emission intensity of the wavelength conversion member over time. The content of MgO + CaO + SrO + BaO is 0.1 to 45%, and preferably 0.1 to 40%, 0.1 to 35%, 1 to 30%, and especially 5 to 25%. If the content of MgO + CaO + SrO + BaO is too small, the softening point is difficult to lower. On the other hand, if the content of MgO + CaO + SrO + BaO is too large, the weather resistance is likely to decrease. The content of each of the components MgO, CaO, SrO and BaO is 0 to 35%, and preferably 0.1 to 33%, and especially 1 to 30%. If the content of these components is too high, weather resistance tends to decrease.

ZnO is a component that lowers the melting temperature and improves melting properties. The ZnO content is 0-4%, preferably 0-3%, more preferably 0-1.8%, and even more preferably 0.1-1.5%. If the ZnO content is too high, weather resistance tends to decrease. In addition, phase separation tends to occur, decreasing transmittance, and as a result, luminescence intensity tends to decrease.

In addition to the above components, various components can be contained within a range that does not impair the effects of the present invention. For example, _P2O5 , _{La2O3 , Ta2O5 , TeO2 , TiO2, Nb2O5, Gd2O3, Y2O3 , CeO2 , Sb2O3 , SnO2 , Bi2O3 , As2O3 , and ZrO2} may each be contained in an amount of 15% or less, further 10% or less, particularly 5% or _less , and a total amount of ₃₀ % or less. F can also be contained. Since F has the effect of lowering _the softening point, by containing it instead of an alkali metal component, which is one of the causes of color center formation, it is possible to suppress the decrease in emission intensity over time while maintaining a low softening point. The F content is preferably 0 to 10%, more preferably 0 to 8%, and even more preferably 0.1 to 5%, in terms of anion %.

Fe and Cr are components that reduce visible light transmittance and cause a decrease in luminescence intensity. Therefore, it is preferable that the Fe content is 1000 ppm or less, particularly 500 ppm or less. It is also preferable that the Cr content is 500 ppm or less, particularly 100 ppm or less. However, in order to prevent the inclusion of Fe and Cr in the glass, it is necessary to use expensive high-purity raw materials, which tends to increase production costs. Therefore, from the viewpoint of reducing production costs, it is preferable that the Fe and Cr contents are each 5 ppm or more, particularly 10 ppm or more.

The softening point of the glass matrix is preferably 600 to 1100°C, 630 to 1050°C, and particularly preferably 650 to 1000°C. If the softening point of the glass matrix is too low, the mechanical strength and weather resistance are likely to decrease. On the other hand, if the softening point is too high, the sintering temperature will also be high, and the inorganic phosphor will be more likely to deteriorate during the firing process during production.

The inorganic phosphor in the present invention is at least one selected from the group consisting of oxide phosphors (including garnet phosphors such as YAG phosphors), nitride phosphors, oxynitride phosphors, chloride phosphors, oxychloride phosphors, halide phosphors, aluminate phosphors, and halophosphate chloride phosphors. Among these inorganic phosphors, oxide phosphors, nitride phosphors, and oxynitride phosphors are preferred because they have high heat resistance and are relatively resistant to deterioration during firing. In addition, nitride phosphors and oxynitride phosphors have the characteristic of converting near-ultraviolet to blue excitation light into a wide wavelength range from green to red, and also have a relatively high emission intensity. Therefore, nitride phosphors and oxynitride phosphors are particularly effective as inorganic phosphors used in wavelength conversion members for white LED elements. In order to suppress the conduction of heat generated from the inorganic phosphor to the glass matrix, a coated inorganic phosphor may be used. This suppresses the activation of the movement of electrons, holes, and alkali ions in the glass matrix, and as a result, the formation of color centers can be suppressed. An oxide is preferred as the coating material. Other examples of phosphors besides those mentioned above include sulfide phosphors, but these are not used in the present invention because they tend to deteriorate over time and react with the glass matrix, resulting in a decrease in luminescence intensity.

The above-mentioned inorganic phosphors include those that have an excitation band at wavelengths of 300 to 500 nm and an emission peak at wavelengths of 380 to 780 nm, and in particular those that emit blue (wavelengths of 440 to 480 nm), green (wavelengths of 500 to 540 nm), yellow (wavelengths of 540 to 595 nm), and red (wavelengths of 600 to 700 nm).

Examples of inorganic phosphors that emit 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⁺ and (Sr,Ba) ₃ MgSi ₂ O ₈ :Eu ²⁺ .

Examples of inorganic phosphors that emit green fluorescence when irradiated with ultraviolet to near-ultraviolet excitation light with a wavelength of 300 to 440 nm include SrAl ₂ O ₄ :Eu ²⁺ , SrBaSiO ₄ :Eu ²⁺ , Y ₃ (Al, Gd) ₅ O ₁₂ :Ce ³⁺ , SrSiON: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⁺ , etc.

Examples of inorganic phosphors that emit green fluorescence when irradiated with blue excitation light having a wavelength of 440 to 480 nm include _SrAl2O4 : _Eu2 ⁺ , _SrBaSiO4 :Eu2 ⁺ , _Y3 (Al,Gd) _5O12 : ^Ce3+ , SrSiON:Eu2 ⁺ , β-SiAlON:Eu2 ⁺ _, and the like.

An example of an inorganic phosphor that emits yellow fluorescence when irradiated with ultraviolet to near-ultraviolet excitation light having a wavelength of 300 to 440 nm is La ₃ Si ₆ N ₁₁ :Ce ³⁺ .

Examples of inorganic phosphors that emit 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⁺ .

Examples of inorganic phosphors that emit red fluorescence when irradiated with ultraviolet to near-ultraviolet excitation light having a wavelength of 300 to 440 nm include MgSr ₃ Si ₂ O ₈ :Eu ²⁺ , Mn ²⁺ and Ca ₂ MgSi ₂ O ₇ :Eu ²⁺ , Mn ²⁺ .

Examples of inorganic phosphors 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⁺ , and α-SiAlON:Eu ²⁺ .

In addition, multiple inorganic phosphors may be mixed to suit the wavelength range of the excitation light and emission. For example, when irradiating with ultraviolet excitation light to obtain white light, inorganic phosphors that emit blue, green, yellow, and red fluorescence may be mixed and used.

In general, inorganic phosphors often have a higher refractive index than glass. In a wavelength conversion member, if the difference in refractive index between the inorganic phosphor and the glass matrix is large, the excitation light is more likely to be scattered at the interface between the inorganic phosphor and the glass matrix. As a result, the efficiency of irradiation of the excitation light to the inorganic phosphor increases, and the luminous efficiency tends to improve. However, if the difference in refractive index between the inorganic phosphor and the glass matrix is too large, the excitation light is excessively scattered, resulting in scattering losses and a tendency for the luminous efficiency to decrease. In view of the above, it is preferable that the difference in refractive index between the inorganic phosphor and the glass matrix is about 0.001 to 0.5. In addition, the refractive index (nd) of the glass matrix is preferably 1.45 to 1.8, more preferably 1.47 to 1.75, and even more preferably 1.48 to 1.6.

The luminous efficiency (lm/W) of the wavelength conversion member varies depending on the type and content of the inorganic phosphor, as well as the thickness of the wavelength conversion member. The content of the inorganic phosphor and the thickness of the wavelength conversion member may be appropriately adjusted so as to optimize the luminous efficiency. If the content of the inorganic phosphor is too high, problems such as difficulty in sintering, increased porosity, difficulty in efficiently irradiating the inorganic phosphor with excitation light, and reduced mechanical strength of the wavelength conversion member may occur. On the other hand, if the content of the inorganic phosphor is too low, it is difficult to obtain the desired luminous intensity. From this viewpoint, the content of the inorganic phosphor in the wavelength conversion member of the present invention is preferably 0.01 to 70 mass%, more preferably 0.05 to 50 mass%, and even more preferably 0.08 to 30 mass%.

Note that in wavelength conversion materials intended to reflect the fluorescence generated in the wavelength conversion material toward the excitation light incident side and extract mainly only the fluorescence to the outside, the above is not the only option, and the content of inorganic phosphor can be increased (for example, 30 to 80 mass %, or even 40 to 75 mass %) to maximize the emission intensity.

In addition to the inorganic phosphor, the wavelength conversion member of the present invention may contain light diffusing materials such as alumina, silica, magnesia, etc. in a total amount of up to 30 mass %.

The wavelength conversion member of the present invention is preferably made of a powder sintered body. Specifically, it is preferably made of a sintered body of a mixed powder containing glass powder and inorganic phosphor powder. In this way, it is possible to easily produce a wavelength conversion member in which the inorganic phosphor is uniformly dispersed in the glass matrix.

The maximum particle size _Dmax of the glass powder is preferably 200 μm or less, 150 μm or less, particularly preferably 105 μm or less. The average particle size _D50 of the glass powder is preferably 0.1 μm or more, 1 μm or more, particularly preferably 2 μm or more. If the maximum particle size _Dmax of the glass powder is too large, the excitation light is less likely to be scattered in the obtained wavelength conversion member, and the luminous efficiency is likely to decrease. If the average particle size _D50 of the glass powder is too small, the excitation light is excessively scattered in the obtained wavelength conversion member, and the luminous efficiency is likely to decrease.

In the present invention, the maximum particle size D _max and the average particle size D ₅₀ refer to values measured by a laser diffraction method.

The firing temperature of the mixed powder containing glass powder and inorganic phosphor is preferably within ±150°C of the softening point of the glass powder, and particularly within ±100°C of the softening point of the glass powder. If the firing temperature is too low, the glass powder will not flow sufficiently, making it difficult to obtain a dense sintered body. On the other hand, if the firing temperature is too high, the inorganic phosphor components may dissolve into the glass, reducing the luminescence intensity, or the inorganic phosphor components may diffuse into the glass, causing the glass to become colored and reducing the luminescence intensity.

It is preferable that the firing is performed in a reduced pressure atmosphere. Specifically, the atmosphere during firing is preferably less than 1.013×10 ⁵ Pa, 1000 Pa or less, and particularly 400 Pa or less. This can reduce the amount of bubbles remaining in the wavelength conversion member. As a result, the scattering factor in the wavelength conversion member can be reduced, and the luminous efficiency can be improved. The entire firing process may be performed in a reduced pressure atmosphere, or, for example, only the firing process may be performed in a reduced pressure atmosphere, and the temperature increase process and temperature decrease process before and after the firing process may be performed in an atmosphere other than a reduced pressure atmosphere (for example, under atmospheric pressure).

The shape of the wavelength conversion member of the present invention is not particularly limited, and includes, for example, not only members having a specific shape such as a plate, a column, a hemisphere, or a hemispherical dome, but also sintered bodies in the form of a coating formed on the surface of a substrate such as a glass substrate or a ceramic substrate.

An anti-reflection film or a fine uneven structure layer may be provided on the surface of the wavelength conversion member. In this way, the light reflectance on the surface of the wavelength conversion member is reduced, improving the light extraction efficiency and the emission intensity.

Anti-reflective films include single-layer films or multi-layer films (dielectric multi-layer films) made of oxides, nitrides, fluorides, etc., and can be formed by sputtering, vapor deposition, coating, etc. The light reflectance of the anti-reflective film is preferably 5% or less, 4% or less, and particularly 3% or less at wavelengths of 380 to 780 nm.

The fine uneven structure layer may have a moth-eye structure with a size equal to or smaller than the wavelength of visible light. Examples of methods for producing the fine uneven structure layer include nanoimprinting and photolithography. Alternatively, the fine uneven structure layer may be formed by roughening the surface of the wavelength conversion member by sandblasting, etching, polishing, or the like. The surface roughness Ra of the uneven structure layer is preferably 0.001 to 0.3 μm, 0.003 to 0.2 μm, and particularly preferably 0.005 to 0.15 μm. If the surface roughness Ra is too small, it is difficult to obtain the desired anti-reflection effect. On the other hand, if the surface roughness Ra is too large, light scattering increases, and the emission intensity is likely to decrease.

Figure 1 shows an example of an embodiment of a light-emitting device of the present invention. As shown in Figure 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 L1. The excitation light L1 incident on the wavelength conversion member 2 is converted into fluorescence L2 of a different wavelength, and is emitted from the opposite side of the light source 3. At this time, a composite light of the excitation light L1 that has passed through without being wavelength converted and the fluorescence L2 may be emitted.

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

(1) Preparation of Glass Powder Tables 1 to 5 show the glass powders (samples 1 to 39) used in the examples and the glass powders (samples 40 and 41) used in the comparative examples.

Raw materials were mixed to obtain the glass compositions shown in Tables 1 to 5, and vitrified by melting in a platinum crucible at 1200 to 1700°C for 1 to 2 hours. The molten glass was cast between a pair of cooling rollers to form a film. The obtained film-like glass molded body was pulverized in a ball mill and then classified to obtain a glass powder having an average particle size _D50 of 2.5 μm. The obtained glass powder was measured for thermal expansion coefficient, density, strain point, annealing point, softening point, and weather resistance by the following methods.

The thermal expansion coefficient was measured using a dilatometer in the range of 30 to 380°C.

Density was measured using the Archimedes method.

The strain point, annealing point and softening point were measured using a fiber elongation method, and the temperatures at which the viscosities were 10 ^14.5 dPa·s, 10 ^13.0 dPa·s and 10 ^7.6 dPa·s, respectively, were adopted.

Weather resistance was evaluated as follows. Glass powder was pressure molded in a mold to produce a cylindrical preform with a diameter of 1 cm, and then fired at the firing temperatures shown in Tables 1 to 5 to obtain cylindrical sintered body samples. Using a Hirayama Seisakusho HAST tester PC-242HSR2, the samples were held at 121°C, 95% RH, and 2 atm for 300 hours, and the weather resistance was evaluated by observing the surface. Specifically, samples that showed no change in the surface before and after the test under optical microscope observation (x500) were rated as "○", and samples that showed precipitation of glass components on the surface or loss of gloss were rated as "×".

(2) Preparation of Wavelength Conversion Member Tables 6 to 14 show examples of the present invention (samples A-1 to A-39, B-1 to B-39) and comparative examples (A-40, A-41, B-40, B-41).

Each glass powder sample shown in Tables 1 to 5 was mixed with the inorganic phosphor powder shown in Tables 6 to 14 in a specified mass ratio to obtain a mixed powder. The mixed powder was pressure molded in a mold to produce a cylindrical preform with a diameter of 1 cm. The preform was fired, and the resulting sintered body was then processed to obtain a wavelength conversion member with a size of 1.2 mm square and a thickness of 0.2 mm. The firing temperatures shown in Tables 1 to 5 were used depending on the glass powder used.

The wavelength conversion member was placed on an LED chip with an emission wavelength of 445 nm and energized at 650 mA, and was continuously irradiated with light for 100 hours. The energy distribution spectrum of light emitted from the upper surface of the wavelength conversion member in an integrating sphere was measured for the wavelength conversion member before and after light irradiation using a general-purpose emission spectrum measuring device. The total luminous flux value was calculated by multiplying the obtained emission spectrum by the standard relative luminous efficiency. The rate of change in the total luminous flux value was expressed as a value (%) obtained by dividing the total luminous flux value after light irradiation by the total luminous flux value before light irradiation and multiplying the result by 100. The results are shown in Tables 6 to 14.

As is clear from Tables 6 to 14, when YAG was used as the inorganic phosphor, the wavelength conversion members of Examples A-1 to A-39 maintained a total luminous flux value of 99.5% or more of the value before light irradiation even after 100 hours of light irradiation, whereas the wavelength conversion members of Comparative Examples A-40 and A-41 had a total luminous flux value of 98% or less of the value before light irradiation after 100 hours of light irradiation.

In addition, when α-SiAlON was used as the inorganic phosphor, the wavelength conversion members of Examples B-1 to B-39 maintained a total luminous flux value of 99% or more of the value before light irradiation even after 100 hours of light irradiation, whereas the wavelength conversion members of Comparative Examples B-40 and B-41 had a total luminous flux value of 94% or less of the value before light irradiation after 100 hours of light irradiation.

The wavelength conversion material of the present invention is suitable as a component of general lighting such as white LEDs and special lighting (e.g., projector light sources, vehicle lighting such as vehicle headlights, etc.).

1 Light emitting device 2 Wavelength conversion member 3 Light source

Claims (14)

A wavelength conversion member having an inorganic phosphor dispersed in a glass matrix,
the glass matrix contains, in mole percent, 67-85 % _SiO2 , 0-20 % _{B2O3 ,} 0-25 % Al2O3, 0-3% Li2O _{, 0-3} % Na2O, 0-3% _K2O , _0-3 % _Li2O + _Na2O +K2O, 0-35% MgO, 0-35% CaO, 0-35 _% SrO, 0-35% _BaO , 0.1-45% MgO+CaO+SrO+BaO, and 0-4% ZnO;
The softening point of the glass matrix is 829 to 1100° C.;
The wavelength conversion member, wherein the inorganic phosphor is at least one selected from the group consisting of oxide phosphors, nitride phosphors, oxynitride phosphors, chloride phosphors, oxychloride phosphors, halide phosphors, aluminate phosphors, and halophosphate chloride phosphors. A wavelength conversion member having an inorganic phosphor dispersed in a glass matrix,
The glass matrix is, in mol %, SiO ₂ 30-85%, B ₂ O ₃ 8-20%, Al ₂ O ₃ 0-25%, Li ₂ O 0-3%, Na ₂ O 0-3%, K ₂ O 0-3%, Li ₂ O+Na ₂ O+K ₂ O 0-3%, MgO 0-35%, CaO 0-35%, SrO 0-35%, BaO 0-35%, MgO+CaO+SrO+BaO 0.1-45%, and ZnO 0-4%;
The softening point of the glass matrix is 829 to 1100° C.;
The wavelength conversion member, wherein the inorganic phosphor is at least one selected from the group consisting of oxide phosphors, nitride phosphors, oxynitride phosphors, chloride phosphors, oxychloride phosphors, halide phosphors, aluminate phosphors, and halophosphate chloride phosphors. A wavelength conversion member having an inorganic phosphor dispersed in a glass matrix,
The glass matrix is, in mol %, SiO ₂ 30-85%, B ₂ O ₃ 0-20%, Al ₂ O ₃ 0-4%, Li ₂ O 0-3%, Na ₂ O 0-3%, K ₂ O 0-3%, Li ₂ O+Na ₂ O+K ₂ O 0-3%, MgO 0-35%, CaO 0-35%, SrO 0-35%, BaO 0-35%, MgO+CaO+SrO+BaO 0.1-45%, and ZnO 0-4%;
The softening point of the glass matrix is 829 to 1100° C.;
The wavelength conversion member, wherein the inorganic phosphor is at least one selected from the group consisting of oxide phosphors, nitride phosphors, oxynitride phosphors, chloride phosphors, oxychloride phosphors, halide phosphors, aluminate phosphors, and halophosphate chloride phosphors. A wavelength conversion member having an inorganic phosphor dispersed in a glass matrix,
The glass matrix is, in mol %, SiO ₂ 30-85%, B ₂ O ₃ 0-20%, Al ₂ O ₃ 0-25%, Li ₂ O 0-3%, Na ₂ O 0-3%, K ₂ O 0-3%, Li ₂ O+Na ₂ O+K ₂ O 0-3%, MgO 0-35%, CaO 0-9%, SrO 0-35%, BaO 0-35%, MgO+CaO+SrO+BaO 0.1-45%, and ZnO 0-4%;
The softening point of the glass matrix is 829 to 1100° C.;
The wavelength conversion member, wherein the inorganic phosphor is at least one selected from the group consisting of oxide phosphors, nitride phosphors, oxynitride phosphors, chloride phosphors, oxychloride phosphors, halide phosphors, aluminate phosphors, and halophosphate chloride phosphors. A wavelength conversion member having an inorganic phosphor dispersed in a glass matrix,
The glass matrix is, in mol %, SiO ₂ 30-85%, B ₂ O ₃ 0-20%, Al ₂ O ₃ 0-25%, Li ₂ O 0-3%, Na ₂ O 0-3%, K ₂ O 0-3%, Li ₂ O+Na ₂ O+K ₂ O 0-3%, MgO 0-35%, CaO 0-35%, SrO 0.5-35%, BaO 0-35%, MgO+CaO+SrO+BaO 0.5-45%, and ZnO 0-4%;
The softening point of the glass matrix is 829 to 1100° C.;
The wavelength conversion member, wherein the inorganic phosphor is at least one selected from the group consisting of oxide phosphors, nitride phosphors, oxynitride phosphors, chloride phosphors, oxychloride phosphors, halide phosphors, aluminate phosphors, and halophosphate chloride phosphors. A wavelength conversion member having an inorganic phosphor dispersed in a glass matrix,
The glass matrix is, in mol %, SiO ₂ 30-85%, B ₂ O ₃ 0-20%, Al ₂ O ₃ 0-25%, Li ₂ O 0-3%, Na ₂ O 0-3%, K ₂ O 0-3%, Li ₂ O+Na ₂ O+K ₂ O 0-3%, MgO 0-35%, CaO 0-35%, SrO 0-35%, BaO 0-1%, MgO+CaO+SrO+BaO 0.1-45%, and ZnO 0-4%;
The softening point of the glass matrix is 829 to 1100° C.;
The wavelength conversion member, wherein the inorganic phosphor is at least one selected from the group consisting of oxide phosphors, nitride phosphors, oxynitride phosphors, chloride phosphors, oxychloride phosphors, halide phosphors, aluminate phosphors, and halophosphate chloride phosphors. A wavelength conversion member having an inorganic phosphor dispersed in a glass matrix,
The glass matrix is, in mol %, SiO ₂ 30-61.5%, B ₂ O ₃ 0-20%, Al ₂ O ₃ 0-25%, Li ₂ O 0-3%, Na ₂ O 0-3%, K ₂ O 0-3%, Li ₂ O+Na ₂ O+K ₂ O 0-3%, MgO 0-35%, CaO 0-35%, SrO 0-35%, BaO 0-35%, MgO+CaO+SrO+BaO 0.1-45%, and ZnO 0-4%;
The softening point of the glass matrix is 829 to 1100° C.;
The wavelength conversion member, wherein the inorganic phosphor is at least one selected from the group consisting of oxide phosphors, nitride phosphors, oxynitride phosphors, chloride phosphors, oxychloride phosphors, halide phosphors, aluminate phosphors, and halophosphate chloride phosphors. A wavelength conversion member having an inorganic phosphor dispersed in a glass matrix,
The glass matrix is, in mol %, SiO ₂ 30-85%, B ₂ O ₃ 0-20%, Al ₂ O ₃ 10.5-25%, Li ₂ O 0-3%, Na ₂ O 0-3%, K ₂ O 0-3%, Li ₂ O+Na ₂ O+K ₂ O 0-3%, MgO 0-35%, CaO 0-35%, SrO 0-35%, BaO 0-35%, MgO+CaO+SrO+BaO 0.1-45%, and ZnO 0-4%;
The softening point of the glass matrix is 829 to 1100° C.;
The wavelength conversion member, wherein the inorganic phosphor is at least one selected from the group consisting of oxide phosphors, nitride phosphors, oxynitride phosphors, chloride phosphors, oxychloride phosphors, halide phosphors, aluminate phosphors, and halophosphate chloride phosphors. A wavelength conversion member having an inorganic phosphor dispersed in a glass matrix,
The glass matrix is, in mol %, SiO ₂ 30-85%, B ₂ O ₃ 0-20%, Al ₂ O ₃ 0-25%, Li ₂ O 0-3%, Na ₂ O 0-3%, K ₂ O 0-3%, Li ₂ O+Na ₂ O+K ₂ O 0-3%, MgO 0-35%, CaO 0-35%, SrO 0-35%, BaO 14-35%, MgO+CaO+SrO+BaO 14-45%, and ZnO 0-4%,
The softening point of the glass matrix is 829 to 1100° C.;
The wavelength conversion member, wherein the inorganic phosphor is at least one selected from the group consisting of oxide phosphors, nitride phosphors, oxynitride phosphors, chloride phosphors, oxychloride phosphors, halide phosphors, aluminate phosphors, and halophosphate chloride phosphors. The wavelength conversion member according to any one of claims 1 to 9 , wherein the inorganic phosphor is contained in an amount of 0.01 to 70 mass %. The wavelength conversion member according to any one of claims 1 to 10 , which is made of a sintered powder body. A light emitting device comprising: the wavelength conversion member according to any one of claims 1 to 11 ; and a light source that irradiates the wavelength conversion member with excitation light. An in-vehicle lighting device comprising the light-emitting device according to claim 12 . 14. The vehicle-mounted lighting device according to claim 13 , which is used as a headlight.