Wavelength conversion component and light emitting device using the same

Abstract

Provided is a wavelength conversion member in which a phosphor powder is dispersed in a glass matrix, the wavelength conversion member having excellent luminous efficiency. The wavelength conversion member is formed by dispersing a phosphor powder in a glass matrix, the glass matrix having a refractive index (nd) of 1.6 or more and a liquidus temperature of 1070°C or less.

Description

[0001] (This application is a divisional application of application 201980006504.5, filed on March 25, 2019, entitled "Wavelength Conversion Component and Light Emitting Device Using the Wavelength Conversion Component") Technical Field

[0002] The present invention relates to a wavelength conversion component that converts the wavelength emitted by a light-emitting diode (LED) or laser diode (LD) into other wavelengths, and to a light-emitting device using the wavelength conversion component. Background Technology

[0003] In recent years, as a next-generation light-emitting device to replace fluorescent and incandescent lamps, there has been increasing attention on light-emitting devices using excitation light sources such as LEDs or LDs, based on the viewpoints of low power consumption, small size, lightweight design, and easy light intensity adjustment. As an example of such a next-generation light-emitting device, Patent Document 1 discloses a light-emitting device in which a wavelength conversion component is arranged on an LED that emits blue light, absorbing part of the light from the LED and converting it into yellow light. This light-emitting device emits white light as a composite light of the blue light emitted from the LED and the yellow light emitted from the wavelength conversion component.

[0004] As a wavelength conversion component, existing technologies utilize components formed by dispersing phosphor powder in a resin matrix. However, when using this wavelength conversion component, there are problems such as resin degradation due to light from the excitation source and a tendency for the brightness of the light-emitting device to decrease. In particular, there is a problem that the molding resin is prone to degradation due to the heat emitted by the excitation source and high-energy short-wavelength (blue to ultraviolet) light, leading to discoloration or deformation.

[0005] Therefore, a wavelength conversion component consisting entirely of inorganic solids, in which phosphor powder is dispersed and fixed within a glass matrix, has been proposed as an alternative to a resin matrix (see, for example, Patent Documents 2 and 3). This wavelength conversion component features that the glass, as the base material, is not easily degraded by the heat or irradiation of the LED, and is less prone to discoloration or deformation.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2000-208815

[0009] Patent Document 2: Japanese Patent Application Publication No. 2003-258308

[0010] Patent Document 3: Japanese Patent No. 4895541 Summary of the Invention

[0011] The technical problem that the invention aims to solve

[0012] To improve the luminous efficiency of wavelength conversion components, it is crucial to effectively extract the fluorescence generated by these components to the outside. To this end, it is known that reducing the thickness of the wavelength conversion component and increasing the concentration of phosphor powder can mitigate absorption losses caused by the glass matrix. However, increasing the concentration of phosphor powder increases internal scattering of excitation light and fluorescence, tending to decrease luminous efficiency. Furthermore, when the softening point of the glass matrix is ​​lowered to seal the heat-sensitive phosphor powder, internal scattering of excitation light and fluorescence also increases, leading to a further decrease in luminous efficiency.

[0013] In view of the above problems, the object of the present invention is to provide a wavelength conversion component formed by dispersing phosphor powder in a glass matrix, which has excellent luminous efficiency.

[0014] Technical means for solving technical problems

[0015] The wavelength conversion component of this invention is characterized by being a wavelength conversion component formed by dispersing phosphor powder in a glass matrix. Typically, the refractive index (nd) of the glass matrix is ​​above 1.6, and the liquidus temperature is below 1070°C. The phosphor powders used in wavelength conversion components generally have high refractive indices. Increasing the mixing concentration of the phosphor powder leads to increased internal scattering due to the refractive index difference with the glass matrix, resulting in a tendency for decreased luminous efficiency. Therefore, by increasing the refractive index of the glass matrix as described above, the refractive index difference with the phosphor powder is reduced, mitigating internal scattering. Furthermore, lowering the softening point of the glass matrix can easily lead to devitrification during firing, resulting in a tendency for decreased luminous efficiency due to scattering caused by the refractive index difference between the precipitated crystals (devitrified material) and the glass matrix. In this invention, by lowering the liquidus temperature of the glass matrix (increasing the liquidus viscosity) as described above, devitrification during firing can be suppressed, and internal scattering can be reduced. Thus, a wavelength conversion component with excellent luminous efficiency can be achieved.

[0016] The wavelength conversion component of the present invention preferably contains, by mass percentage, 25-50% SiO2, 0.1-8% Al2O3, more than 0% and less than 15% B2O3, 0-10% MgO, 0-15% CaO, 0-15% SrO, 0.1-50% BaO, 0-20% ZnO, 0-10% ZrO2, 0-5% Nb2O5, 2.1-15% TiO2, and 0.1-15% La2O3, and the ratio of (TiO2+La2O3) / B2O3 is 0.5 or higher. With this characteristic, a wavelength conversion component having the desired properties described above can be easily obtained. Specifically, by containing the specified amounts of TiO2 and La2O3 in the glass matrix, the refractive index can be increased. Furthermore, by optimizing the contents of TiO2, La2O3, and B2O3 as described above, a glass with excellent devitrification resistance can be obtained. Here, "(TiO2+La2O3) / B2O3" refers to the value obtained by dividing the total amount of TiO2 and La2O3 by the content of B2O3.

[0017] The wavelength conversion component of the present invention preferably has a Li₂O + Na₂O + K₂O content of 0-5% in the glass matrix. This improves the devitrification resistance of the glass matrix. Here, "Li₂O + Na₂O + K₂O" refers to the total amount of Li₂O, Na₂O, and K₂O.

[0018] The wavelength conversion component of the present invention preferably has an Sb2O3 content of less than 0.2% in the glass matrix.

[0019] The wavelength conversion component of the present invention preferably uses phosphor powder selected from at least one of nitride phosphors, oxynitride phosphors, oxide phosphors, sulfide phosphors, oxysulfide phosphors, halide phosphors and aluminate phosphors.

[0020] The wavelength conversion component of the present invention preferably contains 0.01 to 70% by volume of phosphor powder.

[0021] The wavelength conversion component of the present invention preferably comprises a sintered body containing a mixture of glass powder and phosphor powder. This facilitates the uniform dispersion of the phosphor powder within the glass matrix, making the light emitted from the wavelength conversion component more homogeneous.

[0022] The light-emitting device of the present invention is characterized by having the above-described wavelength conversion component and a light source for irradiating excitation light onto the wavelength conversion component.

[0023] Invention Effects

[0024] According to the present invention, a wavelength conversion component formed by dispersing phosphor powder in a glass matrix can be provided, which has excellent luminous efficiency. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a light-emitting device according to one embodiment of the present invention. Detailed Implementation

[0026] The wavelength conversion component of the present invention is formed by dispersing phosphor powder in a glass matrix.

[0027] The refractive index (nd) of the glass matrix is ​​preferably 1.6 or higher, 1.64 or higher, 1.65 or higher, 1.67 or higher, 1.68 or higher, 1.69 or higher, and especially 1.7 or higher. When the refractive index of the glass matrix is ​​too low, internal scattering increases due to the refractive index difference between the glass matrix and the phosphor powder, tending to decrease the luminous efficiency of the wavelength conversion component. On the other hand, when the refractive index of the glass matrix is ​​too high, there is also a concern that internal scattering will increase due to the refractive index difference between the glass matrix and the phosphor powder. Therefore, the refractive index of the glass matrix is ​​preferably 2.2 or lower, 2.1 or lower, 2 or lower, and especially 1.9 or lower. Furthermore, to increase the refractive index, alkaline earth metal oxides (MgO, CaO, SrO, BaO) or components such as ZrO2, Nb2O5, TiO2, and La2O3 can be included. Alternatively, the upper limit of the content of components such as SiO2, Al2O3, and B2O3, which tend to lower the refractive index, can be limited.

[0028] The liquidus temperature (TL) of the glass matrix is ​​below 1070℃, 1060℃, 1040℃, 1020℃, 1000℃, 980℃, 960℃, and especially below 940℃. When the liquidus temperature is too high, devitrification is likely during firing, and there is a tendency for scattering due to the refractive index difference between the precipitated crystals and the glass matrix, leading to a decrease in luminescence efficiency. Furthermore, there is no specific lower limit for the liquidus temperature; in practice, it is above 700℃ and further above 800℃. In addition, to lower the liquidus temperature, Al₂O₃, B₂O₃, ZnO, ZrO₂, etc., can be included. The (TiO₂+La₂O₃) / B₂O₃ ratio can be appropriately adjusted.

[0029] The composition of the glass matrix is ​​preferably selected to possess the aforementioned characteristics. For example, a glass with the following composition can be listed as follows (by mass percentage): SiO2 25–50%, Al2O3 0.1–8%, B2O3 greater than 0 and less than 15%, MgO 0–10%, CaO 0–15%, SrO 0–15%, BaO 0.1–50%, ZnO 0–20%, ZrO2 0–10%, Nb2O5 0–5%, TiO2 2.1–15%, La2O3 0.1–15%, and (TiO2+La2O3) / B2O3 greater than 0.5. The reasons for such a limited glass composition will be explained below. In the following descriptions of the content of each component, unless otherwise specified, "%" refers to "mass %".

[0030] SiO2 is a component that forms the glass network. When the SiO2 content decreases, it tends to be difficult to form a glass network structure, and vitrification becomes more challenging. There is also a tendency for chemical resistance to decrease. Wavelength conversion components are sometimes acid-cleaned after processing; if the chemical resistance of the glass matrix is ​​low, it can deteriorate, potentially leading to a decrease in luminous efficiency. Therefore, the SiO2 content is preferably 25% or more, particularly 30% or more. On the other hand, increasing the SiO2 content tends to lead to a decrease in refractive index or a deterioration in melt flowability. Therefore, the SiO2 content is preferably 50% or less, 48% or less, 45% or less, particularly 40% or less.

[0031] Al₂O₃ contributes to the balance and stability of glass composition and improves resistance to devitrification. However, excessive Al₂O₃ content increases the liquidus temperature, making devitrification more likely during melting or firing. Furthermore, it tends to decrease the refractive index. Therefore, the Al₂O₃ content is preferably 8% or less, 6% or less, and particularly 5% or less. On the other hand, to achieve the aforementioned effects, the Al₂O₃ content is preferably 0.1% or more, 0.5% or more, and particularly 1% or more.

[0032] B₂O₃ is a component that lowers the liquidus temperature and improves resistance to devitrification. However, excessive B₂O₃ content can easily lead to a decrease in refractive index and softening point. Once the softening point of the glass matrix decreases, the heat resistance of the glass decreases, and the wavelength conversion components may soften and deform due to the heat generated during excitation light irradiation. Therefore, the B₂O₃ content is preferably 15% or less, 10% or less, and particularly 8% or less. On the other hand, to achieve the above-mentioned effects, the B₂O₃ content is preferably more than 0%, more than 1%, more than 2%, and particularly more than 5%.

[0033] MgO is a component that increases the refractive index. It also improves melt flow. However, when its content is too high, the glass composition becomes unbalanced, devitrification resistance decreases, and phase separation easily occurs. Therefore, the MgO content is preferably 10% or less, 8% or less, 6% or less, or 3%. Furthermore, to obtain the above-mentioned effects, the MgO content is preferably 0.1% or more, and particularly 0.5% or more.

[0034] CaO is a component that increases the refractive index. It also improves melt flow. However, if its content is too high, the glass composition becomes unbalanced, and the resistance to devitrification tends to decrease. Therefore, the CaO content is preferably below 15%, and especially below 10%. Furthermore, to obtain the above-mentioned effects, the CaO content is preferably above 1%, above 2%, above 3%, and especially above 5%.

[0035] SrO is a component that increases the refractive index. It also improves melt flow. However, when its content is too high, the glass composition becomes unbalanced, and devitrification resistance tends to decrease. Therefore, the SrO content is preferably below 15%, 12%, 10%, 9%, 8%, 7%, and especially below 6%. Furthermore, to obtain the above-mentioned effects, the SrO content is preferably above 0.5%, 1%, 2%, 3%, and especially above 3.5%.

[0036] BaO is a component among alkaline earth metal oxides that effectively increases the refractive index. However, excessive BaO content leads to an imbalance in the glass composition and a decrease in devitrification resistance. Therefore, the BaO content is preferably below 50%, 40%, 35%, and especially below 30%. Furthermore, to achieve the aforementioned effects, the BaO content is preferably above 0.1%, 10%, 20%, 22%, and especially above 25%.

[0037] ZnO is a component that improves devitrification resistance. However, excessive ZnO content can lead to an imbalance in the glass composition, resulting in a decrease in devitrification resistance and chemical resistance. Therefore, the ZnO content is preferably below 30%, 20%, 15%, 10%, 5%, or 2%, and more preferably substantially non-existent. In this specification, "substantially non-existent" means that it is not intentionally contained as a raw material, but does not exclude the possibility of unavoidable impurities. Objectively speaking, it means that the content of the corresponding component is less than 0.1%.

[0038] ZrO2 is a component that increases refractive index and improves resistance to devitrification and chemical treatment. However, excessive ZrO2 content can easily decrease devitrification resistance. Therefore, the ZrO2 content is preferably below 10%, below 8%, below 5%, and especially below 3%. Furthermore, there is no particular limitation on the lower limit; it can be 0%, but to achieve the aforementioned effects, the ZrO2 content is preferably above 0.1%, above 1%, and especially above 2%.

[0039] Nb₂O₅ is a component that increases the refractive index. However, excessive Nb₂O₅ content can easily lead to a decrease in devitrification resistance and visible light transmittance, and also increase raw material costs. Therefore, the Nb₂O₅ content is preferably below 5%, below 3%, below 1%, and more preferably substantially absent.

[0040] TiO2 is a component that increases the refractive index and improves chemical resistance. However, excessive TiO2 content can easily reduce devitrification resistance. Therefore, the TiO2 content is preferably below 15%, below 13%, and especially below 11%. Furthermore, to achieve the aforementioned effects, the TiO2 content is preferably above 1%, above 2.1%, above 3%, and especially above 5%.

[0041] La2O3 is a component that improves refractive index and chemical resistance. However, excessive content can easily reduce devitrification resistance. Therefore, the content of La2O3 is preferably below 25%, 15%, 14%, 13%, 12%, and especially below 10%. Furthermore, to achieve the aforementioned effects, the content of La2O3 is preferably above 0.1%, 1%, 2.5%, 3%, 5%, and especially above 7%.

[0042] By appropriately adjusting the (TiO2+La2O3) / B2O3 ratio, both devitrification resistance and chemical resistance can be balanced. The (TiO2+La2O3) / B2O3 ratio is preferably 0.5 or higher, 1 or higher, and especially 1.5 or higher. When the (TiO2+La2O3) / B2O3 ratio is too low, chemical resistance tends to decrease, and the refractive index tends to be low. Furthermore, while there is no particular upper limit to the (TiO2+La2O3) / B2O3 ratio, if this value is too high, there is a tendency for the liquid phase viscosity to decrease and the devitrification tendency to increase; therefore, a value of 6 or lower, 4 or lower, 3.5 or lower, and especially 3 or lower, is preferred.

[0043] Li₂O, Na₂O, and K₂O are components that enhance the devitrification tendency. Therefore, the content of Li₂O+Na₂O+K₂O is preferably 5% or less, 3% or less, and 1% or less, and particularly preferably substantially absent. Furthermore, the content of each component Li₂O, Na₂O, and K₂O is preferably 5% or less, 3% or less, and 1% or less, respectively, and particularly preferably substantially absent.

[0044] Sb2O3 is a component that functions as a clarifying agent, but since it is an environmentally burdensome substance, its content is preferably less than 0.2%, and more preferably substantially non-existent.

[0045] In addition to Sb₂O₃, one or more of the following can be added as clarifying agents: As₂O₃, CeO₂, SnO₂, F, Cl, and SO₃, with a total amount of 0-3%. However, from an environmental point of view, it is preferable to control the use of As₂O₃ and F, especially As₂O₃, as much as possible, and preferably to eliminate them substantially. From an environmental point of view, SnO₂, SO₃, or Cl is preferred as a clarifying agent. The SnO₂ content is preferably 0-1%, 0.01-0.5%, and particularly 0.05-0.4%. Furthermore, the SnO₂+SO₃+Cl content is preferably 0-1%, 0.001-1%, 0.01-0.5%, and particularly 0.01-0.3%. Here, "SnO₂+SO₃+Cl" refers to the total amount of SnO₂, SO₃, and Cl.

[0046] PbO is a component that increases the refractive index, but from an environmental point of view, it is preferable to have it practically absent.

[0047] Ta₂O₅, Gd₂O₃, Y₂O₃, and Yb₂O₃ are components that increase the refractive index, but because they are rare raw materials, they lead to increased raw material costs. Therefore, their contents are preferably below 5%, below 3%, and below 1%, respectively, and in particular, practically non-existent.

[0048] WO3 is a component that increases the refractive index, but it is prone to significantly precipitating devitrification spots during glass forming, especially reducing the transmittance of visible light in the short wavelength range. Therefore, its content is preferably below 5%, below 3%, below 1%, or in particular, practically non-existent.

[0049] TeO2 is a component that significantly expands the glass transition range, substantially suppresses the precipitation of devitrification spots, and increases the refractive index. However, because it is a rare raw material, it leads to increased raw material costs. Therefore, its content is preferably below 5%, below 3%, below 1%, and especially practically non-existent.

[0050] Bi2O3 is a component that increases the refractive index, but it easily reduces visible light transmittance. Furthermore, as it is a rare raw material, it increases raw material costs. Therefore, it is preferable to have virtually no Bi2O3.

[0051] GeO2 improves glass transition stability and increases refractive index. However, as it is a rare raw material, it increases raw material costs. Therefore, it is preferable to have virtually no GeO2.

[0052] HfO2 is a component that increases the refractive index, but because it is a rare raw material, it increases the cost of raw materials. Therefore, it is preferable that it is not present in the material.

[0053] Furthermore, the softening point of the glass matrix is ​​preferably above 600°C, and especially above 620°C. A higher softening point of the glass results in higher heat resistance, and is therefore preferred.

[0054] The wavelength conversion component of the present invention is formed, for example, from a sintered body containing a mixture of glass powder and phosphor powder. Regarding the particle size of the glass powder, for example, a maximum particle size D is preferred. max Below 200 μm (especially below 150 μm, and further below 105 μm), and with an average particle size D 50 The maximum particle size D of glass powder is above 0.1 μm (especially above 1 μm, and further above 2 μm). max When the particle size is too large, the dispersion of the phosphor powder deteriorates, and the emission color is prone to unevenness. The average particle size D... 50 If the wavelength is too small, the excitation light will be excessively scattered inside the wavelength conversion component, which can easily lead to a decrease in luminous efficiency.

[0055] In this invention, the maximum particle size D max and average particle size D 50 The value was obtained using laser diffraction.

[0056] The phosphor powder that can be used in this invention is any product that is commonly available on the market and is not particularly limited. Examples include nitride phosphors, oxynitride phosphors, oxide phosphors (including garnet-based phosphors such as YAG phosphors), sulfide phosphors, oxysulfide phosphors, halide phosphors (such as halogenated phosphates), and aluminate phosphors. They can be used alone or in combination. Among these phosphor powders, nitride phosphors, oxynitride phosphors, and oxide phosphors are preferred because of their high heat resistance and resistance to degradation during firing. In addition, nitride phosphors and oxynitride phosphors have the characteristics of being able to convert near-ultraviolet to blue excitation light into green to red wavelengths and also having high luminous intensity. Therefore, nitride phosphors and oxynitride phosphors are particularly effective as phosphor powders for wavelength conversion components for white LED elements.

[0057] Examples of phosphor powders mentioned above include powders that have an excitation band in the wavelength range of 300–500 nm and an emission peak in the wavelength range of 380–780 nm, particularly powders that emit blue (wavelength 440–480 nm), green (wavelength 500–540 nm), yellow (wavelength 540–595 nm), and red (wavelength 600–700 nm) light. Furthermore, various phosphor powders can be mixed and used according to the wavelength range of the excitation or emission light. For example, when white light is obtained by irradiation with ultraviolet excitation light, phosphor powders emitting blue, green, yellow, and red fluorescence can be mixed and used.

[0058] Wavelength conversion components can be obtained by sintering a mixture containing glass powder and phosphor powder (wavelength conversion material) near the softening point of the glass powder. Sintering is preferably carried out under reduced pressure. Specifically, it is preferable to sinter at a pressure below 1.013 × 10⁻⁶. 5 The firing process is carried out under a reduced pressure atmosphere of 1000 Pa or less, especially 400 Pa or less. This reduces the amount of residual bubbles in the wavelength conversion component. As a result, the scattering factor caused by bubbles in the wavelength conversion component is reduced, and the luminous efficiency is improved. In addition, the firing process can be carried out entirely in a reduced pressure atmosphere, or, for example, only the heating process can be carried out in a reduced pressure atmosphere, while the holding and cooling processes before and after it are carried out in a non-reduced pressure atmosphere (e.g., at atmospheric pressure).

[0059] The luminous efficiency (lm / W) of the wavelength conversion component varies depending on the type and content of the phosphor powder, its particle size, and the thickness of the wavelength conversion component. The content of the phosphor powder and the thickness of the wavelength conversion component can be appropriately adjusted to achieve optimal luminous efficiency. Excessive phosphor powder content leads to problems such as difficulty in sintering, increased porosity, difficulty in efficiently irradiating the phosphor powder with excitation light, and a decrease in the mechanical strength of the wavelength conversion component. Conversely, insufficient phosphor powder content makes it difficult to obtain the desired chromaticity and luminous intensity. From this perspective, the phosphor powder content in the wavelength conversion component of the present invention, by volume percentage, is preferably adjusted to within the range of 0.01–70%, more preferably 2–50%, and even more preferably 3–30%.

[0060] In contrast, in reflective wavelength conversion components that reflect the fluorescence generated in the wavelength conversion component toward the incident side of the excitation light and whose main purpose is to lead the fluorescence outward only, the above limitation does not apply. In order to maximize the luminescence intensity, the content of phosphor powder can be increased (for example, 30-80% or even 40-75% by volume percentage).

[0061] In the wavelength conversion component of the present invention, in addition to containing glass and phosphor powder, fillers such as alumina or magnesium oxide, in a total mass percentage of 50% or less, may be included for purposes such as improving heat dissipation. The average particle size D of the filler is... 50 Preferably, the particle size is 0.1–50 μm, more preferably 0.3–30 μm, even more preferably 0.5–20 μm, and particularly preferably 1–10 μm. The average particle size D of the filler... 50 When the particle size is too large, the dispersion in the wavelength conversion component decreases, easily leading to uneven color of the emitted light. On the other hand, the average particle size D of the filler... 50 When the particle size is too small, the contact between the filler particles decreases and the distance between them increases, making it difficult to fully achieve the effect of improving heat release.

[0062] The difference in refractive index (nd) between the filler and the glass matrix, expressed in absolute value, is preferably 1.0 or less, more preferably 0.8 or less, further preferably 0.5 or less, and particularly preferably 0.3 or less. This suppresses internal scattering caused by the refractive index difference between the filler and the glass matrix, thereby suppressing the decrease in luminous intensity.

[0063] The shape of the wavelength conversion component of the present invention is not particularly limited, and includes not only components with specific shapes such as plate-shaped, column-shaped, hemispherical, spherical, and hemispherical dome-shaped, but also film-shaped sintered bodies formed on the surface of substrates such as glass substrates or ceramic substrates.

[0064] Figure 1 This represents one embodiment of the light-emitting device of the present invention. For example... Figure 1 As shown, the light-emitting device 1 has a wavelength conversion component 2 and a light source 3. The light source 3 irradiates excitation light onto the wavelength conversion component 2. The excitation light L1 incident on the wavelength conversion component 2 is converted into light L2 of a different wavelength and emitted from the side opposite to the light source 3. At this time, a composite light consisting of the wavelength-converted light L2 and the excitation light L1 that has not been wavelength-converted and transmitted can also be emitted.

[0065] Example

[0066] The present invention will be described in detail below based on embodiments, but the present invention is not limited to these embodiments.

[0067] Tables 1 to 3 show the examples (samples No. 1 to 23) and comparative examples (samples No. 24 to 26).

[0068] [Table 1]

[0069]

[0070] [Table 2]

[0071]

[0072] [Table 3]

[0073]

[0074] (1) Preparation of glass powder

[0075] First, raw materials are prepared according to the glass composition listed in Tables 1-3 to obtain a masterbatch. The obtained masterbatch is fed into a glass melting furnace and melted at 1300-1500°C. Then, it flows out between a pair of cooling rollers, thereby forming a film. The obtained film glass is dry-milled using a ball mill to obtain an average particle size D. 50 The glass powder has a particle size of 6–9 μm. Additionally, partially molten glass is poured onto a carbon plate and shaped into a flat plate, then subjected to a prescribed annealing process to obtain bulk glass.

[0076] For bulk glass, the refractive index (nd), liquidus temperature (TL), and softening point (Ts) were evaluated according to the following method. The results are shown in Tables 1-3.

[0077] The refractive index was measured using a Shimadzu KPR-2000 refractive index meter, with the d-line (wavelength 587.6 nm) of a He lamp as the measurement value was obtained.

[0078] The softening point was determined based on ASTM C336-71.

[0079] The liquidus temperature was measured by the following operation: the block glass was crushed using an agate mortar and pestle, and the resulting glass powder was passed through a standard 30-mesh sieve (500 μm). The glass powder remaining on the 50-mesh sieve (300 μm) was placed in a platinum crucible and kept in a temperature gradient furnace for 24 hours. The temperature at which crystallization occurred was then measured.

[0080] (2) Fabrication of wavelength conversion components

[0081] As described in Tables 1-3, phosphor powder is mixed with various glass powders in specified amounts to obtain a mixed powder. The mixed powder is then pressed and molded using a mold to produce a cylindrical preform with a diameter of 1 cm. The preform is then fired at the temperatures specified in the tables to obtain the wavelength conversion component.

[0082] The chemical resistance and beam value of the obtained wavelength conversion components were evaluated. The results are shown in Tables 1-3.

[0083] Chemical resistance was evaluated as follows. The wavelength conversion component was machined to a size of 10 mm × 50 mm × 0.7 mm, mirror-polished using 1 μm diamond abrasive, and immersed in an etching solution (Kanto Chemical ITO-06N) at 50 °C for 15 minutes. After rinsing the sintered body with water, the step difference between the YAG phosphor powder and the glass matrix was measured using a SURFCODER ET4000 (Kosaka Laboratory), and this value was used to evaluate chemical resistance. A step difference between the phosphor powder and the glass matrix (i.e., no etching of the glass matrix) was recorded as "-".

[0084] The beam value was measured as follows. The wavelength conversion component was fabricated into a disk shape with a diameter of 8 mm and a thickness of 0.2 mm. To reduce the influence of surface reflection caused by the refractive index difference with the light source or atmosphere, an anti-reflective coating of dielectric multilayer film was applied to the surface. The wavelength conversion component was placed on a light source consisting of an LED chip with an excitation wavelength of 460 nm powered by an input current of 1000 mA, and the energy distribution spectrum of the light emitted from the upper surface of the sample was measured within an integrating sphere. Then, the obtained spectrum was multiplied by the standard relative luminous efficiency to calculate the full beam.

[0085] The wavelength conversion components No. 1 to 23, as examples, have glass substrates with refractive indices as high as 1.66 or higher and liquidus temperatures as low as 1048°C or lower, resulting in beam values ​​as high as 188 (lm) or higher. In particular, the wavelength conversion components No. 1 to 22 also exhibit excellent chemical resistance. On the other hand, the wavelength conversion component No. 24, as a comparative example, has a liquidus temperature as high as 1075°C, while the wavelength conversion components No. 25 and 26, as comparative examples, have refractive indices as low as 1.56 or lower, resulting in beam values ​​as low as 175 (lm) or lower.

[0086] Industrial availability

[0087] This invention is suitable for use as a wavelength conversion component in general lighting and special lighting (e.g., projector light sources, automotive headlight sources) such as white LEDs.

[0088] Symbol Explanation

[0089] 1: Light-emitting device; 2: Wavelength conversion component; 3: Light source.

Claims

1. A wavelength conversion component, characterized in that, It is made by dispersing phosphor powder in a glass matrix. The glass matrix has a refractive index (nd) above 1.6 and a liquidus temperature below 1070℃. The content of La2O3 in the glass matrix is ​​above 0.1% by mass, and the ratio of (TiO2 + La2O3) to B2O3 is above 1.

5.

2. A wavelength conversion component, characterized in that, It is made by dispersing phosphor powder in a glass matrix. The glass matrix has a refractive index (nd) above 1.6 and a liquidus temperature below 1070℃. The glass matrix contains more than 0.1% by mass of La2O3 and 0.5% to 15% by mass of SrO.

3. The wavelength conversion component as described in claim 1 or 2, characterized in that, The La2O3 content in the glass matrix is ​​0.1–25% by mass.

4. The wavelength conversion component as described in claim 1 or 2, characterized in that, The SiO2 content in the glass matrix is ​​1.6% by mass or more.

5. The wavelength conversion component as described in claim 1 or 2, characterized in that, The SiO2 content in the glass matrix is ​​1.6–50% by mass.

6. The wavelength conversion component as described in claim 1 or 2, characterized in that, By mass percentage, the glass matrix contains 1.6–50% SiO2, more than 0% B2O3 but less than 26.5%, and 0.1–25% La2O3.

7. The wavelength conversion component as claimed in claim 1, characterized in that, By mass percentage, the glass matrix contains 1.6–50% SiO2, 0.1–8% Al2O3, more than 0% and less than 26.5% B2O3, 0–10% MgO, 0–15% CaO, 0–15% SrO, 0.1–50% BaO, 0–30% ZnO, 0–10% ZrO2, 0–5% Nb2O5, 1–15% TiO2, and 0.1–25% La2O3.

8. The wavelength conversion component as described in claim 2, characterized in that, By mass percentage, the glass matrix contains 1.6–50% SiO2, 0.1–8% Al2O3, more than 0% and less than 26.5% B2O3, 0–10% MgO, 0–15% CaO, 0.1–50% BaO, 0–30% ZnO, 0–10% ZrO2, 0–5% Nb2O5, 1–15% TiO2, and 0.1–25% La2O3.

9. The wavelength conversion component as described in claim 1 or 2, characterized in that, The content of Li2O+Na2O+K2O in the glass matrix is ​​0-5%.

10. The wavelength conversion component as claimed in claim 1 or 2, characterized in that, The Sb₂O₃ content in the glass matrix is ​​less than 0.2%.

11. The wavelength conversion component as claimed in claim 1 or 2, characterized in that, The phosphor powder is selected from at least one of nitride phosphors, oxynitride phosphors, oxide phosphors, sulfide phosphors, oxysulfide phosphors, halide phosphors and aluminate phosphors.

12. The wavelength conversion component as described in claim 1 or 2, characterized in that, Contains 0.01 to 70% by volume phosphor powder.

13. The wavelength conversion component as described in claim 1 or 2, characterized in that, This includes sintered bodies containing a mixture of glass powder and phosphor powder.

14. A light-emitting device, characterized in that, Having a wavelength conversion component as described in any one of claims 1 to 13, and A light source that irradiates the wavelength conversion component with excitation light.

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