Wavelength conversion member

Abstract

Provided is a wavelength conversion member capable of easily adjusting chromaticity when irradiated with light from an LED or LD.　A wavelength conversion member 1 comprises a wavelength conversion member body 10 obtained by dispersing inorganic phosphors 12 in an inorganic matrix 11, and a filter layer 20 formed on one surface of the wavelength conversion member body 10, the wavelength conversion member 1 being characterized in that the filter layer 20 suppresses transmission of light in an excitation band of the inorganic phosphors 12, and transmits light having the emission peak wavelength of the inorganic phosphors 12.

Description

Wavelength conversion material

[0001] 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) into another wavelength.

[0002] In recent years, light sources using LEDs and LDs have been attracting increasing attention as next-generation light sources to replace fluorescent lamps and incandescent lamps, due to their low power consumption, small size, light weight, and easy light intensity adjustment. Patent Document 1, for example, discloses an example of such a next-generation light source, in which a wavelength conversion member is disposed on an LED that emits blue light, and the wavelength conversion member absorbs part of the light from the LED and converts it to yellow light. This light source emits white light, which is a composite light of the blue light emitted from the LED and the yellow light emitted from the wavelength conversion member.

[0003] Conventionally, wavelength conversion materials have been used in which inorganic phosphors are dispersed in a resin matrix. However, when such wavelength conversion materials are used, there is a problem that the resin is easily degraded by light from an LED, which reduces the brightness of the light source. In particular, there is a problem that the resin matrix is ​​degraded by heat and high-energy short-wavelength (blue to ultraviolet) light emitted by the LED, causing discoloration and deformation.

[0004] Therefore, wavelength conversion members made of a completely inorganic solid, in which inorganic phosphors are dispersed and fixed in a glass matrix instead of a resin, have been proposed (see, for example, Patent Documents 2 and 3). These wavelength conversion members have the advantage that the glass base material is less likely to deteriorate due to heat or irradiated light from the LED chip, and are less likely to suffer from problems such as discoloration or deformation.

[0005] Japanese Patent Application Laid-Open No. 2000-208815 Japanese Patent Application Laid-Open No. 2003-258308 Japanese Patent No. 4895541

[0006] However, the light obtained by a light-emitting device using a wavelength conversion member is a composite light that is a combination of excitation light emitted from an LED and passed through the wavelength conversion member, as described above, and fluorescence emitted from a phosphor, and therefore it is difficult to effectively utilize the color of the fluorescence, and it is sometimes difficult to obtain light of the desired chromaticity.

[0007] In view of the above, an object of the present invention is to provide a wavelength conversion member that can emit light of a desired chromaticity when irradiated with light from an LED or LD.

[0008] A wavelength conversion member that solves the above problems will be described.

[0009] A wavelength conversion member according to aspect 1 of the present invention is a wavelength conversion member comprising a wavelength conversion member body formed by dispersing an inorganic phosphor in an inorganic matrix, and a filter layer provided on one surface of the wavelength conversion member body, wherein the filter layer suppresses transmission of light in the excitation band of the inorganic phosphor and transmits light of the emission peak wavelength of the inorganic phosphor.

[0010] In the wavelength conversion member according to Aspect 2 of the present invention, in Aspect 1, it is preferable that the excitation band of the inorganic phosphor is between wavelengths of 300 nm and 480 nm, and the emission peak wavelength of the inorganic phosphor is 500 nm or more and 700 nm or less.

[0011] A wavelength conversion member according to Aspect 3 of the present invention is the wavelength conversion member of Aspect 1 or 2, wherein the filter layer is preferably a dielectric multilayer film.

[0012] A wavelength conversion member according to Aspect 4 of the present invention is, in Aspect 3, preferably such that the total number of laminated dielectric multilayer films is 10 or more.

[0013] A wavelength conversion member according to Aspect 5 of the present invention is any one of Aspects 1 to 4, wherein the inorganic phosphor includes at least one selected from a nitride phosphor and an oxynitride phosphor.

[0014] A wavelength conversion member according to Aspect 6 of the present invention is any one of Aspects 1 to 5, wherein the inorganic matrix preferably contains glass or ceramics.

[0015] A wavelength conversion member according to Aspect 7 of the present invention is preferably, in any one of Aspects 1 to 6, such that the wavelength conversion member is placed under a light source with an excitation peak wavelength of 450 nm, light emitted from the lower surface of the wavelength conversion member is taken into an integrating sphere, and the chromaticity calculated from the measured light energy distribution spectrum is a chromaticity Cx of 0.45 to 0.65 and a chromaticity Cy of 0.35 to 0.50.

[0016] A wavelength conversion member according to Aspect 8 of the present invention is the wavelength conversion member of any one of Aspects 1 to 7, wherein the cut-on wavelength of the filter layer is preferably 480 nm or more and 680 nm or less.

[0017] A wavelength conversion member according to Aspect 9 of the present invention is any one of Aspects 1 to 8, wherein the filter layer is preferably disposed on the emission surface side of the wavelength conversion member.

[0018] A wavelength conversion member according to Aspect 10 of the present invention is preferably, in Aspect 9, wherein the filter layer also serves as a filter that cuts off part of the short wavelength side of the emission spectrum of the inorganic phosphor.

[0019] A wavelength conversion member according to aspect 11 of the present invention is a wavelength conversion member comprising an inorganic phosphor dispersed in an inorganic matrix, wherein the inorganic phosphor comprises 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, and the content of the inorganic phosphor is 25 mass% or more.

[0020] According to the present invention, it is possible to provide a wavelength conversion member that can emit light of a desired chromaticity when irradiated with light from an LED or LD.

[0021] FIG. 1 is a schematic cross-sectional view showing a wavelength conversion member according to a first embodiment of the present invention. FIG. 2 is a schematic side view of a light-emitting device according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of a filter layer according to a first embodiment of the present invention. FIG. 4 is a schematic cross-sectional view of a wavelength conversion member according to a second embodiment of the present invention. FIG. 5 is a graph showing the spectral transmittance curve of the filter layer according to the first embodiment of the present invention at an incident angle of 0°. FIG. 6 is a graph showing the emission spectra of Example 1 and Comparative Example 1. FIG. 7(a) is a graph showing the emission spectra of Examples 2 to 6, and FIG. 7(b) is a graph showing the emission spectra of Comparative Examples 2 and 3. FIG. 8 is a graph showing the emission spectra of Examples 7 and 8. FIG. 9 is a diagram showing the chromaticity Cx and chromaticity Cy of Examples 1 to 8 and Comparative Examples 1 to 3. FIG. 10 is a graph showing the spectral transmittance curve of the filter layers obtained in Examples 9 to 11 at an incident angle of 0°. FIG. 11 is a graph showing the emission spectra of Examples 9 to 11.

[0022] (First embodiment) Fig. 1 is a schematic cross-sectional view showing a wavelength conversion member 1 according to a first embodiment of the present invention. As shown in Fig. 1, the wavelength conversion member 1 is constructed by providing a filter layer 20 on one surface of a wavelength conversion member main body 10. In this embodiment, the wavelength conversion member main body 10 is formed by dispersing inorganic phosphors 12 in an inorganic matrix 11. In this embodiment, the filter layer 20 is formed on one surface of the wavelength conversion member main body 10.

[0023] (Filter layer 20) The wavelength conversion member 1 according to the first embodiment of the present invention includes a filter layer 20 on one surface of the wavelength conversion member body 10. The filter layer 20 is a filter layer that suppresses transmission of light having a wavelength in the excitation band of the inorganic phosphor 12 and transmits light having a wavelength at the emission peak of the inorganic phosphor 12.

[0024] FIG. 2 shows an example of an embodiment of a light-emitting device of the present invention. As shown in FIG. 2, the light-emitting device 3 includes a wavelength conversion member 1 and a light source 30. The light source 30 irradiates the wavelength conversion member 1 with excitation light L0 having a wavelength in the excitation band of the inorganic phosphor 12 contained therein. The excitation light L0 incident on the wavelength conversion member 1 is converted into light of a different wavelength by entering the inorganic phosphor 12 contained therein, and is emitted as fluorescence L1 having the emission peak wavelength of the inorganic phosphor 12 from the wavelength conversion member 1 opposite the light source 30. In the light-emitting device 3 shown in FIG. 2, a filter layer 20 is typically formed on the emission surface side of the wavelength conversion member 1 (the right side in FIG. 2), which is the opposite side of the wavelength conversion member 1 from the light source 30. The wavelength conversion member 1 and the light-emitting device 3 are manufactured by forming a filter layer 20 on the surface of the emission surface side of the wavelength conversion member main body 10. As a result, in the first embodiment of the present invention, the filter layer 20 suppresses transmission of the excitation light L0 that would otherwise be transmitted without wavelength conversion and transmits the fluorescence L1. As a result, it is possible to effectively utilize the fluorescence of the inorganic phosphor 12 and easily obtain light of a desired chromaticity in the light-emitting device 3. Note that, by changing the configuration of the filter layer 20 as necessary, it is possible to transmit a portion of the excitation light L0 and emit it as combined light with the fluorescence L1.

[0025] Here, the excitation band of inorganic phosphor 12 is preferably between 300 nm and 480 nm, more preferably between 380 nm and 470 nm, and even more preferably between 430 nm and 460 nm. Furthermore, the wavelength of the emission peak of inorganic phosphor 12 is preferably between 500 nm and 700 nm, more preferably between 550 nm and 670 nm, and even more preferably between 580 nm and 650 nm. This further suppresses transmission of blue light, which is excitation light, and allows greater transmission of yellow to red light, which is fluorescence from inorganic phosphor 12, making it easier to obtain light of the desired chromaticity in light-emitting device 3.

[0026] The filter layer 20 may be a single layer or a multilayer (dielectric multilayer) made of an oxide, nitride, fluoride, etc. The filter layer 20 does not need to be formed on the entire one surface of the wavelength conversion member body 10, but may be formed on at least a part of the surface of the wavelength conversion member body 10.

[0027] Such a filter layer 20 can be formed, for example, by a dielectric multilayer film 40 having incident angle dependency, which is formed by alternately stacking low-refractive index layers 41L having a relatively low refractive index and high-refractive index layers 41H having a relatively high refractive index, as shown in Fig. 3. The low-refractive index layers 41L can be formed, for example, of silicon oxide, aluminum oxide, magnesium fluoride, etc. The high-refractive index layers 41H can be formed, for example, of niobium oxide, titanium oxide, zirconium oxide, lanthanum oxide, tantalum oxide, yttrium oxide, gadolinium oxide, tungsten oxide, hafnium oxide, silicon oxynitride, silicon nitride, aluminum nitride, etc.

[0028] The thickness of the low refractive index layer 41L of the dielectric multilayer film 40 can be, for example, about 1.5 nm to 150 nm. The thickness of the high refractive index layer 41H can be, for example, about 1.5 nm to 150 nm. The thickness of each layer in the dielectric multilayer film 40 is not limited to the above.

[0029] The total number of high-refractive-index layers 41H and low-refractive-index layers 41L in the dielectric multilayer film 40 is preferably 10 or more, more preferably 14 or more, even more preferably 16 or more, even more preferably 18 or more, even more preferably 20 or more, even more preferably 22 or more, even more preferably 24 or more, even more preferably 25 or more, and is preferably 200 or less, more preferably 150 or less, even more preferably 100 or less, even more preferably 80 or less, and even more preferably 60 or less. If the total number of layers is too small, it may be difficult to narrow the wavelength band in the transition portion from the transmission wavelength range to the non-transmission wavelength range in the dielectric multilayer film 40 and achieve a steep gradient. On the other hand, if the total number of layers is too large, distortion occurs in the dielectric multilayer film 40, making it more susceptible to peeling or cracking from the substrate.

[0030] The total film thickness of the dielectric multilayer film 40 is preferably 15 nm or more, more preferably 50 nm or more, even more preferably 100 nm or more, even more preferably 300 nm or more, even more preferably 500 nm or more, even more preferably 700 nm or more, even more preferably 1000 nm or more, and preferably 3000 nm or less, more preferably 2500 nm or less. If the total film thickness is too small, it may be difficult to narrow the wavelength band in the transition portion from the transmission wavelength range to the non-transmission wavelength range in the dielectric multilayer film 40 and achieve a steep gradient. On the other hand, if the total film thickness is too large, distortion occurs in the dielectric multilayer film 40, making it more susceptible to peeling from the substrate or cracking.

[0031] The dielectric multilayer film 40 can be formed on the surface of the wavelength conversion member body 10 using a known film formation method such as sputtering, vacuum deposition, ion beam deposition, ion plating, CVD, etc. Among these film formation methods, sputtering is preferred because it allows the thickness of each layer to be controlled with high precision and can provide a dielectric multilayer film 40 with stable film quality.

[0032] The cut-on wavelength of the filter layer 20 is preferably 480 nm or more, more preferably 510 nm or more, even more preferably 530 nm or more, even more preferably 550 nm or more, even more preferably 560 nm or more, even more preferably 570 nm or more, even more preferably 575 nm or more, and preferably 680 nm or less, more preferably 660 nm or less, even more preferably 640 nm or less, even more preferably 620 nm or less, and even more preferably 600 nm or less. When the cut-on wavelength of the filter layer 20 is equal to or greater than the above-mentioned lower limit, the transmission of light with wavelengths in the excitation band of the inorganic phosphor 12 can be further suppressed, and the transmission of light with wavelengths in the excitation band incident at wide angles can be more reliably suppressed. The cut-on wavelength of the filter layer 20 can be appropriately selected depending on the type of inorganic phosphor 12 used in the wavelength conversion member main body 10, but is preferably equal to or less than the emission peak wavelength of the inorganic phosphor 12, and more preferably shorter than the emission peak wavelength of the inorganic phosphor 12. However, when the cut-on wavelength of the filter layer 20 is equal to or less than the upper limit, the yellow to red light, which is the fluorescence of the inorganic phosphor 12, can be more easily transmitted, making it easier to obtain light of the desired chromaticity in the light-emitting device 3.

[0033] The cut-on wavelength of the filter layer 20 can be determined by measuring the spectral transmittance curve at an incident angle of 0° for a sample in which the filter layer 20 is formed on a glass substrate with a thickness of 0.5 mm. In the spectral transmittance curve, the wavelength at which the transmittance drops to 50% in the direction from the long wavelength side to the short wavelength side can be defined as the cut-on wavelength.

[0034] When the filter layer 20 is the above-described dielectric multilayer film 40, the cut-on wavelength of the filter layer 20 can be shifted to the long wavelength side, for example, by increasing the overall thickness of the low refractive index layer 41L and the high refractive index layer 41H without changing the ratio of their thicknesses. In addition to the above, by adjusting the balance between the thicknesses of the low refractive index layer 41L and the high refractive index layer 41H in the filter layer 20, the transmission of light in a specific wavelength range can be adjusted.

[0035] The filter layer 20 may also serve as a filter that cuts off a portion of the short wavelength side of the emission spectrum of the inorganic phosphor 12. When the filter layer 20 is provided as in the present embodiment, the chromaticity of the light-emitting device 3 is likely to yellow-shift. However, when the filter layer 20 also serves as a filter that cuts off a portion of the short wavelength side of the emission spectrum of the inorganic phosphor 12 as described above, the yellow-shift can be suppressed in the light-emitting device 3, and the chromaticity can be made more reddish.

[0036] In order to suppress yellow shift in the light-emitting device 3 and achieve a redder chromaticity, the cut-on wavelength of the filter layer 20 is preferably 550 nm or more, even more preferably 560 nm or more, even more preferably 570 nm or more, even more preferably 575 nm or more, and is preferably 680 nm or less, more preferably 660 nm or less, even more preferably 640 nm or less, even more preferably 620 nm or less.

[0037] In the light-emitting device 3, the yellow shift can be suppressed and a redder chromaticity can be achieved by increasing the concentration of the inorganic phosphor 12 contained in the wavelength conversion material body 10. However, increasing the concentration of the inorganic phosphor 12 contained in the wavelength conversion material body 10 may reduce the luminous flux value of the light-emitting device 3. In contrast, by designing the cut-on wavelength of the filter layer 20 to be on the long wavelength side as described above, the yellow shift can be suppressed and a redder chromaticity can be achieved in the light-emitting device 3. Therefore, the concentration of the inorganic phosphor 12 contained in the wavelength conversion material body 10 can be designed to be low, thereby further increasing the luminous flux value of the light-emitting device 3.

[0038] (Wavelength conversion material body 10) The wavelength conversion material body 10 is, for example, phosphor glass containing a glass matrix and phosphor powder. The phosphor powder is dispersed in the glass matrix. The shape of the wavelength conversion material body 10 may be selected appropriately depending on the shape of the light emitting device, but in this embodiment, it is a rectangular plate.

[0039] (Inorganic matrix 11) The inorganic matrix 11 is not particularly limited as long as it can be used as a dispersion medium for phosphor particles such as the inorganic phosphor 12. For example, when the inorganic matrix 11 is a glass matrix, borosilicate glass, phosphate glass, tin phosphate glass, bismuthate glass, tellurite glass, etc. can be used. Furthermore, the inorganic matrix 11 may be a ceramic matrix instead of a glass matrix, in which case the thermal conductivity of the wavelength conversion member 1 can be further improved. Examples of ceramics that constitute the ceramic matrix include Al ２ O ３ , MgO, AlN, etc. Furthermore, glass ceramics may be used as the inorganic matrix 11, or an inorganic matrix other than glass or ceramics may be used.

[0040] The glass matrix is ​​preferably glass with a low content of alkali metal components in the glass matrix. This can suppress the formation of color centers in the glass matrix, which act as absorption sources for excitation light and fluorescence, and can suppress a decrease in the luminescence intensity of the wavelength conversion member 1. It can also suppress deterioration of the glass matrix over time under high temperature and high humidity conditions. The glass composition of the glass matrix is, in mol %, Li ２ O + Na ２ O+K ２ O is preferably 0% to 10%, and Li ２ O + Na ２ O+K ２ It is more preferable that O is 0% to 5%, and Li ２ O + Na ２ O+K ２ It is more preferable that O is 0% to 3%.

[0041] For example, borosilicate glass contains, in mole percent, SiO ２ 10% to 85%, B ２ O ３ 0.1%~50%, Al ２ O ３ 0% to 25%, Li ２ O + Na ２ O+K ２Examples of the tin phosphate glass include those containing, in mole percent, 30% to 90% SnO, 0% to 10% O, and 0% to 50% MgO+CaO+SrO+BaO. ２ O ５ The tellurite glass contains, in mole percent, 1% to 70% of TeO. ２ 50% or more, ZnO 0% to 45%, RO (R is at least one selected from Ca, Sr, and Ba) 0% to 50%, and La ２ O ３ +Gd ２ O ３ +Y ２ O ３ Examples include those containing 0% to 50%.

[0042] In particular, borosilicate glass contains, in mole percent, SiO ２ 30% to 85%, B ２ O ３ 4.3%~20%, Al ２ O ３ 0% to 25%, Li ２ O 0% to 3%, Na ２ O 0% to 3%, K ２ O 0% to 3%, Li ２ O + Na ２ O+K ２ It preferably contains O 0% to 3%, MgO 0% to 35%, CaO 0% to 35%, SrO 0% to 35%, BaO 0% to 35%, MgO + CaO + SrO + BaO 0.1% to 45%, and ZnO 0% to 5%.

[0043] In order to further lower the softening point of the glass matrix, the borosilicate glass contains, in mol %, SiO ２ 30% to 80%, B ２ O ３ 1% to 40%, Li ２ O + Na ２ O+K ２ O 0.1% to 35%, MgO + CaO + SrO + BaO 0.1% to 45%, and CeO ２ +As ２ O ３ +MoO ２ +WO３ Glass containing 0.001% to 10% of SiO ２ 30% to 80%, B ２ O ３ 1% to 55%, Li ２ O 0% to 20%, Na ２ O 0% to 25%, K ２ O 0% to 25%, Li ２ O + Na ２ O+K ２ O 0.1% to 35% and CeO ２ +As ２ O ３ +MoO ２ +WO ３ It may also be 0.001% to 10%.

[0044] The reasons for limiting the glass composition range in this way will be explained below. In the following explanation, "%" means "mol %" unless otherwise specified.

[0045] SiO ２ is a component that forms a glass network. SiO ２ The content of SiO is preferably 30% to 85%, and more preferably 35% to 80%. ２ If the content is too low, the weather resistance and mechanical strength tend to decrease. ２ If the content is too large, the sintering temperature becomes high, and the inorganic phosphor is likely to deteriorate during the production of the wavelength conversion member 1 .

[0046] B ２ O ３ is a component that lowers the melting temperature and significantly improves the melting property. ２ O ３ The content of B is preferably 4.3% to 20%, and more preferably 4.3% to 18%. ２ O ３ If the content of B is too small, the fluidity of the glass in the firing step during the production of the wavelength conversion member 1 will be poor, and bubbles will likely remain in the glass matrix. ２ O ３ If the content is too high, the weather resistance tends to decrease.

[0047] Al２ O ３ is a component that improves weather resistance and mechanical strength. ２ O ３ The content of Al is preferably 0% to 25%, and more preferably 0.1% to 20%. ２ O ３ If the content is too high, the melting property tends to decrease.

[0048] Li ２ O, Na ２ O and K ２ O is a component that lowers the melting temperature, improving the melting property, and also lowers the softening point. However, if the content of these components is too high, the weather resistance is likely to decrease, and the light emission intensity is likely to decrease over time when irradiated with light from an LED or LD. Therefore, Li ２ O + Na ２ O+K ２ The content of O is preferably 0% to 3%, more preferably 0% to 2%. ２ O, Na ２ O and K ２ The content of each of the O components is preferably 0% to 3%, and more preferably 0% to 2%. ２ O, Na ２ O.K. ２ When O is contained, it is preferable to use a mixture of two or more kinds, particularly three kinds. In this way, the mixed alkali effect can suppress the decrease over time in the luminous intensity due to light irradiation of LED or LD. From the viewpoint of further lowering the softening point of the glass matrix, Li ２ O, Na ２ O and K ２ The total content of O is preferably 0.1% to 35%, more preferably 1% to 25%, and even more preferably 2% to 20%. If the content of these components is too low, the softening point of the glass matrix is ​​unlikely to decrease, whereas if the content of these components is too high, the chemical durability and weather resistance of the glass matrix are likely to decrease.

[0049] MgO, CaO, SrO, and BaO are components that lower the melting temperature, improve meltability, and lower the softening point. As mentioned above, unlike alkali metal components, these components do not affect the decrease in luminescence intensity of the wavelength conversion member 1 over time. The content of MgO + CaO + SrO + BaO is preferably 0.1% to 45%, more preferably 0.1% to 40%, 0.1% to 35%, 1% to 30%, and particularly preferably 5% to 25%. If the content of MgO + CaO + SrO + BaO is too low, the softening point is less likely to be lowered. On the other hand, if the content of MgO + CaO + SrO + BaO is too high, the weather resistance is likely to be reduced. The content of each of the MgO, CaO, SrO, and BaO components is preferably 0% to 35%, more preferably 0.1% to 33%, and even more preferably 1% to 30%. If the content of these components is too high, the weather resistance tends to decrease.

[0050] ZnO is a component that lowers the melting temperature and improves meltability. The ZnO content is preferably 0% to 5%, more preferably 1% to 4.5%, and even more preferably 1.8% to 4%. If the ZnO content is too high, weather resistance tends to decrease. In addition, phase separation occurs, reducing transmittance and, as a result, luminous intensity tends to decrease.

[0051] In addition, various components may be contained within the range that does not impair the effects of the present invention. For example, P ２ O ５ , La ２ O ３ , Ta ２ O ５ , TeO ２ , TiO ２ , Nb ２ O ５ , Gd ２ O ３ , Y ２ O ３ , CeO ２ , Sb ２ O ３ , SnO ２ , Bi ２ O ３ , As ２ O ３ , MoO ２, W.O. ３ and ZrO ２ The glass composition may contain CeO in an amount of 15% or less, preferably 10% or less, and particularly preferably 5% or less, with the total amount being 30% or less. ２ +As ２ O ３ +MoO ２ +WO ３ By including 0.001% to 10% of Ce, it is possible to suppress the decrease in luminescence intensity of the wavelength conversion member over time. Among these, Ce is particularly preferable because it can significantly suppress the decrease in luminescence intensity over time and, further, the glass powder itself is less likely to be colored. F can also be included. Since F has the effect of lowering the softening point, by including it in place of an alkali metal component, which is one of the causes of color center formation, it is possible to suppress the decrease in luminescence 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 anion %.

[0052] Fe and Cr are components that reduce visible light transmittance and cause a decrease in luminous intensity. Therefore, the Fe content is preferably 1000 ppm or less, more preferably 500 ppm or less. Furthermore, the Cr content is preferably 500 ppm or less, more preferably 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, the Fe and Cr contents are preferably 5 ppm or more, more preferably 10 ppm or more, respectively.

[0053] The softening point of the glass matrix is ​​preferably 250°C to 1000°C, more preferably 300°C to 950°C, and even more preferably 500°C to 900°C. If the softening point of the glass matrix is ​​too low, the mechanical strength and chemical durability of the wavelength conversion member 1 may be reduced. Furthermore, since the heat resistance of the glass matrix itself is low, there is a risk of softening and deformation due to heat generated by the inorganic phosphor 12. On the other hand, if the softening point of the glass matrix is ​​too high, the inorganic phosphor 12 may be deteriorated during the firing step during production, resulting in a decrease in the luminescence intensity of the wavelength conversion member 1. From the viewpoint of further improving the chemical stability and mechanical strength of the wavelength conversion member 1, the softening point of the glass matrix is ​​preferably 500°C or higher, more preferably 550°C or higher, even more preferably 600°C or higher, even more preferably 650°C or higher, even more preferably 700°C or higher, even more preferably 750°C or higher, particularly preferably 800°C or higher, and most preferably 820°C or higher. Examples of glasses constituting such glass matrices include borosilicate glasses. However, as the softening point of the glass matrix increases, the firing temperature also increases, which tends to result in higher manufacturing costs. Furthermore, if the inorganic phosphor 12 has low heat resistance, the inorganic phosphor 12 may be degraded by firing. In particular, when a nitride phosphor or oxynitride phosphor with relatively low heat resistance is used as the inorganic phosphor 12, the inorganic phosphor 12 may be thermally degraded or may react with the glass matrix, causing foaming and resulting in a significant decrease in luminescence intensity and mechanical strength.Therefore, in order to manufacture the wavelength conversion member 1 more inexpensively or in the case where the heat resistance of the inorganic phosphor 12 is lower, the softening point of the glass matrix is ​​preferably 900° C. or less, more preferably 850° C. or less, even more preferably 840° C. or less, even more preferably 830° C. or less, even more preferably 820° C. or less, even more preferably 810° C. or less, even more preferably 800° C. or less, even more preferably 790° C. or less, even more preferably 780° C. or less, even more preferably 760° C. or less, even more preferably 750° C. or less, even more preferably 700° C. or less, even more preferably 650° C. or less, even more preferably 600° C. or less, even more preferably 550° C. or less, even more preferably 530° C. or less, even more preferably 500° C. or less, particularly preferably 480° C. or less, and most preferably 460° C. or less. Examples of glasses constituting such a glass matrix include borosilicate glass, tin phosphate glass, bismuthate glass, and tellurite glass.

[0054] (Inorganic phosphor 12) The inorganic phosphor 12 is at least one selected from the group consisting of, for example, oxide phosphors (including garnet-based 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 12, oxide phosphors, nitride phosphors, and oxynitride phosphors are preferred because they have high heat resistance and are relatively resistant to deterioration during firing.

[0055] Furthermore, nitride phosphors and oxynitride phosphors are characterized by their ability to convert excitation light from near ultraviolet to blue into a wide wavelength range from green to red, and by their relatively high luminescence intensity. A coated inorganic phosphor 12 may be used to prevent heat generated by the inorganic phosphor 12 from being conducted to the inorganic matrix 11. This prevents the active movement of electrons, holes, and alkali ions in the inorganic matrix 11, thereby suppressing the formation of color centers. Oxides are preferred as coating materials. While sulfide phosphors are another example of phosphors other than those mentioned above, they are preferably not used in the present invention because they tend to deteriorate over time and react with the inorganic matrix 11, resulting in a decrease in luminescence intensity.

[0056] Examples of the inorganic phosphor 12 include those having an excitation band in the wavelength range of 300 nm to 500 nm and an emission peak in the wavelength range of 500 nm to 780 nm, and in particular those that emit green light (wavelength of 500 nm to 540 nm), yellow light (wavelength of 540 nm to 595 nm), and red light (wavelength of 600 nm to 700 nm).

[0057] As an inorganic phosphor having an excitation band in the ultraviolet to near ultraviolet wavelength range of 300 nm to 440 nm and a green emission peak, 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 O４ :Eu ２＋ etc.

[0058] As an inorganic phosphor having an excitation band in the blue wavelength range of 440 nm to 480 nm and a green emission peak, SrAl ２ O ４ :Eu ２＋ , Lu ３ Al ５ O １２ :Ce, SrBaSiO ４ :Eu ２＋ , Y ３ (Al, Gd) ５ O １２ : Ce ３＋ , SrSiON:Eu ２＋ , β-SiAlON:Eu ２＋ etc.

[0059] As an inorganic phosphor having an excitation band in the ultraviolet to near ultraviolet wavelength range of 300 nm to 440 nm and a yellow emission peak, La ３ Si ６ N １１ :Ce ３＋ etc.

[0060] As an inorganic phosphor having an excitation band in the blue wavelength range of 440 nm to 480 nm and a yellow emission peak, there is Y ３ (Al, Gd) ５ O １２ : Ce ３＋ , Lu ３ Al ５ O １２ : Ce, Sr ２ SiO ４ :Eu ２＋ Examples include:

[0061] As an inorganic phosphor having an excitation band in the ultraviolet to near ultraviolet wavelength range of 300 nm to 440 nm and a red emission peak, MgSr ３ Si ２ O ８ :Eu ２＋ , Mn ２＋ , Ca ２ MgSi ２ O ７ :Eu ２＋ , Mn２＋ etc.

[0062] As an inorganic phosphor having an excitation band in the blue wavelength range of 440 nm to 480 nm and an emission peak in the yellow to red range, CaAlSiN ３ :Eu ２＋ (CASN), (Ca,Sr)AlSiN ３ :Eu ２＋ (SCASN), CaSiN ３ :Eu ２＋ , (Ca, Sr) ２ Si ５ N ８ :Eu ２＋ , α-SiAlON:Eu ２＋ , Ba ２ Si ５ N ８ :Eu ２＋ , Ce-activated CALSON phosphor, and the like.

[0063] It is also possible to mix multiple inorganic phosphors depending on the wavelength range of the excitation light or emission. For example, when irradiating with ultraviolet excitation light to obtain white light, inorganic phosphors having emission peaks in blue, green, yellow, and red may be mixed and used. When irradiating with blue excitation light to obtain yellow to red light, inorganic phosphors having emission peaks in yellow and red may be mixed and used.

[0064] For example, in the light-emitting device 3, when yellow shift is suppressed and a redder chromaticity is designed, a CASN phosphor or a SCASN phosphor (a phosphor in which part of the Ca in the CASN phosphor is replaced with Sr) can be selected.

[0065] Furthermore, when selecting a CASN phosphor or a SCASN phosphor, it is desirable to use it in combination with another phosphor that has a yellow-red, so-called amber emission peak, such as α-SiAlON. In this case, the ratio of the content of the CASN phosphor and / or SCASN phosphor to the content of all phosphors is, in mass %, preferably 0.1% to 30%, more preferably 1% to 25%, and even more preferably 3% to 20%. By doing so, it becomes easier to achieve a redder chromaticity in the light-emitting device 3, and therefore, when irradiated with light from an LED or LD, it becomes easier to emit light of the desired chromaticity.

[0066] Furthermore, when a mixture of α-SiAlON, CASN phosphor, and / or SCASN phosphor is used as the phosphor powder, the value of (CASN phosphor + SCASN phosphor) / α-SiAlON is preferably 0 or more in mass ratio, more preferably 0.01 or more, even more preferably 0.02 or more, still more preferably 0.03 or more, and even more preferably 0.05 or more. Furthermore, the value of (CASN phosphor + SCASN phosphor) / α-SiAlON is preferably 1 or less in mass ratio, more preferably 0.5 or less, and more preferably 0.3 or less. Note that (CASN phosphor + SCASN phosphor) refers to the total amount of the CASN phosphor and the SCASN phosphor contained.

[0067] CASN phosphors and SCASN phosphors have the problem that they are difficult to seal efficiently (without deterioration), for example. Therefore, if (CASN phosphor + SCASN phosphor) / α-SiAlON is too large and an inorganic matrix 11 with a high softening point is used for the wavelength conversion member 1, the phosphor may deteriorate during the firing process during production, resulting in a decrease in the luminescence intensity of the wavelength conversion member 1. Therefore, when selecting a CASN phosphor or SCASN phosphor, it is desirable to use, for example, a low-softening-point glass as the inorganic matrix 11.

[0068] Examples of low-softening point glasses that can be used include phosphate-based glasses, tin-phosphate-based glasses, bismuthate-based glasses, and tellurite-based glasses. Also, borosilicate-based glasses containing, in mole percent, SiO ２ 30% to 80%, B２ O ３ 1% to 40%, Li ２ O + Na ２ O+K ２ O 0.1% to 35%, MgO + CaO + SrO + BaO 0.1% to 45%, and CeO ２ +As ２ O ３ +MoO ２ +WO ３ Glass containing 0.001% to 10% of SiO ２ 30% to 80%, B ２ O ３ 1% to 55%, Li ２ O 0% to 20%, Na ２ O 0% to 25%, K ２ O 0% to 25%, Li ２ O + Na ２ O+K ２ O 0.1% to 35%, and CeO ２ +As ２ O ３ +MoO ２ +WO ３ Glass containing 0.001% to 10% of Cr can also be used.

[0069] In the light-emitting device 3, the yellow shift can be suppressed and a redder chromaticity can be achieved by increasing the concentration of the inorganic phosphor 12 contained in the wavelength conversion material body 10. However, increasing the concentration of the inorganic phosphor 12 contained in the wavelength conversion material body 10 may reduce the luminous flux value of the light-emitting device 3. In contrast, for example, as described above, if the inorganic phosphor 12 is designed to contain a CASN phosphor or a SCASN phosphor, the yellow shift can be suppressed and a redder chromaticity can be achieved in the light-emitting device 3, and therefore the concentration of the inorganic phosphor 12 contained in the wavelength conversion material body 10 can be designed to be low.

[0070] When a glass matrix is ​​used as the inorganic matrix 11, the inorganic phosphor 12 generally has a higher refractive index than glass. In the wavelength conversion member 1, if the difference in refractive index between the inorganic phosphor 12 and the glass matrix is ​​large, excitation light is more likely to be scattered at the interface between the inorganic phosphor 12 and the glass matrix. As a result, the efficiency of irradiation of the excitation light onto the inorganic phosphor 12 increases, and the luminous efficiency tends to improve. However, if the difference in refractive index between the inorganic phosphor 12 and the glass matrix is ​​too large, the excitation light tends to be excessively scattered, resulting in scattering loss and, conversely, a decrease in luminous efficiency. In view of the above, the difference in refractive index between the inorganic phosphor 12 and the glass matrix is ​​preferably approximately 0.001 to 0.6. Furthermore, 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 1.7.

[0071] The luminous efficiency (lm / W) of the wavelength conversion member 1 varies depending on the type and content of the inorganic phosphor 12, as well as the thickness of the wavelength conversion member 1. The content of the inorganic phosphor 12 and the thickness of the wavelength conversion member 1 can be appropriately adjusted to optimize the luminous efficiency. To obtain the same luminous intensity, increasing the content of the inorganic phosphor 12 allows the thickness of the wavelength conversion member main body 10 to be thinner, which is advantageous for reducing the weight and cost of the light-emitting device 3. If the content of the inorganic phosphor 12 is too low, it becomes difficult to obtain the desired luminous intensity. On the other hand, if the content of the inorganic phosphor 12 is too high, problems such as difficulty in sintering or increased porosity may occur, making it difficult for excitation light to be efficiently irradiated onto the inorganic phosphor 12, or a decrease in the mechanical strength of the wavelength conversion member 1 may occur. From this viewpoint, the content of inorganic phosphor 12 in the wavelength conversion member 1 of the present invention is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, even more preferably 20% by mass or more, even more preferably 25% by mass or more, even more preferably 30% by mass or more, preferably 80% by mass or less, more preferably 70% by mass or less, even more preferably 60% by mass or less, even more preferably 50% by mass or less, and particularly preferably 40% by mass or less.

[0072] Average particle diameter D of inorganic phosphor 12 ５０ The average particle diameter D of the inorganic phosphor 12 is preferably 1 μm or more, 5 μm or more, particularly preferably 10 μm or more, and is preferably 70 μm or less, 50 μm or less, 30 μm or less, or 20 μm or less. ５０ If the average particle diameter D of the inorganic phosphor 12 is too large, the number of voids is likely to increase when the content of the inorganic phosphor 12 is high. On the other hand, if the content of the inorganic phosphor 12 is low, the inorganic phosphor 12 is likely to become uneven in the wavelength conversion member 1, making it difficult to obtain uniform chromaticity. ５０ If the value is too small, the particles react with the inorganic matrix 11 or foam during firing, increasing the porosity (proportion of remaining bubbles) in the wavelength conversion member 1 and making it more likely that the luminous efficiency will decrease.

[0073] In addition to the inorganic phosphor 12, the wavelength conversion member 1 of the present invention may contain a light diffusing material such as alumina, silica, magnesia, or the like in a total amount of up to 30 mass %.

[0074] The wavelength conversion member 1 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 an inorganic matrix 11 and an inorganic phosphor powder. In this way, it becomes possible to easily produce a wavelength conversion member 1 in which the inorganic phosphor 12 is uniformly dispersed in the inorganic matrix 11.

[0075] The wavelength conversion member 1 of the present invention can be produced using a slurry containing inorganic particles that form the inorganic matrix 11, inorganic phosphor particles, and organic components such as a binder resin and a solvent. For example, the wavelength conversion member 1 can be formed by applying the slurry to a resin film such as polyethylene terephthalate using a doctor blade method or the like, heating and drying the film to produce a green sheet, and then firing the green sheet. Alternatively, the wavelength conversion member 1 can be formed by applying the slurry to a substrate to form a film, and then drying and firing the resulting film. The wavelength conversion member 1 can also be produced by firing a compact of a mixed powder containing inorganic particles and inorganic phosphor particles.

[0076] When glass powder is used as the inorganic particles, the maximum particle diameter D of the glass powder isｍａｘ The average particle diameter D of the glass powder is preferably 200 μm or less, 150 μm or less, and particularly preferably 105 μm or less. ５０ The maximum particle diameter D of the glass powder is preferably 0.1 μm or more, 1 μm or more, particularly preferably 2 μm or more, and is preferably 10 μm or less, 8 μm or less, or 5 μm or less. ｍａｘ If the average particle diameter D of the glass powder is too large, the excitation light is less likely to be scattered in the wavelength conversion member 1 obtained, and the luminous efficiency is likely to decrease. ５０ If λ is too small, the excitation light is scattered excessively in the wavelength conversion member 1 obtained, and the luminous efficiency is likely to decrease.

[0077] In the present invention, the maximum particle diameter D ｍａｘ and average particle diameter D ５０ indicates a value measured by a laser diffraction method.

[0078] The firing temperature of the mixed powder containing glass powder and inorganic phosphor is preferably equal to or higher than the softening point of the glass powder, preferably higher than the softening point of the glass powder, and more preferably equal to or higher than the softening point of the glass powder +30°C. Furthermore, it is preferably equal to or lower than the softening point of the glass powder +150°C, more preferably equal to or lower than the softening point of the glass powder +100°C, more preferably equal to or lower than the softening point of the glass powder +90°C, equal to or lower than the softening point of the glass powder +80°C, equal to or lower than the softening point of the glass powder +70°C, equal to or lower than the softening point of the glass powder +60°C, equal to or lower than the softening point of the glass powder +50°C, equal to or lower than the softening point of the glass powder +40°C, equal to or lower than the softening point of the glass powder +30°C, or equal to or lower than the softening point of the glass powder +20°C, more preferably equal to or lower than the softening point of the glass powder +10°C, and even more preferably equal to or lower than the softening point of the glass powder +5°C. If the firing temperature is too low, the glass powder does not flow sufficiently, making it difficult to obtain a dense sintered body. On the other hand, if the firing temperature is too high, the nitride phosphor or oxynitride phosphor may be thermally deteriorated, or the inorganic phosphor may react with the glass, causing foaming and reducing the luminescence intensity and mechanical strength. Furthermore, the inorganic phosphor components may be eluted into the glass, reducing the luminescence intensity, or the inorganic phosphor components may diffuse into the glass, causing the glass to become discolored and reducing the luminescence intensity.

[0079] The firing is preferably carried out in a reduced pressure atmosphere. Specifically, the atmosphere during firing is 1.013 × 10 ５ Preferably, the pressure is less than 1000 Pa, 1000 Pa or less, and particularly 400 Pa or less. This reduces the amount of bubbles remaining in the wavelength conversion member 1. As a result, the scattering factor in the wavelength conversion member 1 can be reduced, and the luminous efficiency can be improved. The firing may be performed in a vacuum atmosphere, an air atmosphere, or a nitrogen atmosphere. 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, with the temperature-raising and temperature-lowering processes before and after the firing process being performed in an atmosphere other than a reduced pressure atmosphere (for example, atmospheric pressure).

[0080] The thickness of the wavelength conversion member body 10 is preferably 1000 μm or less, more preferably 800 μm or less, even more preferably 500 μm or less, and particularly preferably 200 μm or less. If the thickness is too large, it becomes difficult to obtain light of the desired color. Furthermore, the luminous efficiency is likely to decrease. The thickness of the wavelength conversion member body 10 is preferably 10 μm or more, more preferably 20 μm or more, and particularly preferably 50 μm or more. If the thickness is too small, the mechanical strength of the wavelength conversion member body 10 is likely to decrease.

[0081] The surface roughness Ra of at least one surface of the wavelength conversion member body 10 is preferably 100 nm or less, more preferably 80 nm or less, and even more preferably 50 nm or less. Furthermore, the surface roughness Ra is preferably 1 nm or more, more preferably 5 nm or more, and even more preferably 10 nm or more. If the surface roughness Ra is too small, the manufacturing cost increases. On the other hand, if the surface roughness Ra is too large, it becomes difficult to form the filter layer 20 uniformly. To adjust the surface roughness, the wavelength conversion member body 10 after firing may be polished by appropriately selecting a polishing pad or abrasive grains, or may be roughened by sandblasting, etching, or the like.

[0082] Furthermore, from the viewpoint of production costs, if the surface roughness Ra of the surface on the light-emitting surface side of the wavelength conversion member main body 10 is regulated, various surface roughnesses Ra can be adopted for the surface on the opposite side of the light-emitting surface (incident surface side) of the wavelength conversion member 1. In this case, the surface roughness Ra of the surface on the opposite side of the light-emitting surface (incident surface side) of the wavelength conversion member 1 may be 2000 nm or less, 1000 nm or less, 500 nm or less, or 300 nm or less, or may be 1 nm or more, 5 nm or more, 10 nm or more, or 30 nm or more. In this way, production costs can be easily reduced.

[0083] The shape of the wavelength conversion member 1 of the present invention is not particularly limited, and includes not only members having specific shapes themselves such as plate-like, columnar, hemispherical, and hemispherical dome-like, 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.

[0084] Next, a second embodiment of the present invention will be described. In the second embodiment, instead of providing the filter layer 20 of the first embodiment, the content of the inorganic phosphor in the wavelength conversion member 100 is strictly defined, thereby suppressing transmission of light in the excitation band of the inorganic phosphor and transmitting light of the emission wavelength of the inorganic phosphor, thereby obtaining light of a desired chromaticity.

[0085] Second Embodiment Fig. 4 is a schematic cross-sectional view showing a wavelength conversion member 100 according to a second embodiment of the present invention. In this embodiment, the wavelength conversion member 100 is formed by dispersing an inorganic phosphor 120 in an inorganic matrix 110. A glass matrix is ​​used as the inorganic matrix 110. The wavelength conversion member 100 does not include a filter layer.

[0086] In the second embodiment of the present invention, the content of inorganic phosphor 120 in wavelength conversion member 100 is 25 mass % or more.

[0087] The luminous efficiency (lm / W) of the wavelength conversion member 100 varies depending on the type and content of the inorganic phosphor 120, as well as the thickness of the wavelength conversion member 100. The content of the inorganic phosphor 120 and the thickness of the wavelength conversion member 100 can be appropriately adjusted to optimize the luminous efficiency. To obtain the same luminous intensity, increasing the content of the inorganic phosphor 120 allows the thickness of the wavelength conversion member 100 to be thinner, which is advantageous for reducing the weight and cost of the light-emitting device. If the content of the inorganic phosphor 120 is too low, it becomes difficult to suppress the transmission of light at the excitation wavelength of the inorganic phosphor 120, making it difficult to obtain light of the desired chromaticity. It also becomes difficult to obtain the desired luminous intensity. Therefore, the content of the inorganic phosphor 120 in the wavelength conversion member 100 of the present invention is preferably 25% by mass or more, more preferably 30% by mass or more, even more preferably 35% by mass or more, even more preferably 40% by mass or more, even more preferably 45% by mass or more, and even more preferably 50% by mass or more. Furthermore, although there is no upper limit to the content of inorganic phosphor 120, if the content is too high, sintering may become difficult or the porosity may increase, making it difficult for excitation light to be efficiently irradiated onto inorganic phosphor 120. Therefore, in reality, the content is preferably 80 mass % or less, more preferably 75 mass % or less, even more preferably 70 mass % or less, even more preferably 65 mass % or less, and even more preferably 60 mass % or less.

[0088] In the second embodiment of the present invention, the same configuration as the first embodiment can be adopted, except that the wavelength conversion member 100 does not have a filter layer and the content of inorganic phosphor 120 is higher than in the first embodiment.

[0089] In the first and second embodiments of the present invention, a wavelength conversion member is placed under a light source with an excitation peak wavelength of 450 nm, and the chromaticity calculated from the energy distribution spectrum of the light measured by capturing light emitted from the underside of the wavelength conversion member inside an integrating sphere is preferably chromaticity Cx 0.45 to 0.65 and chromaticity Cy 0.35 to 0.50, more preferably chromaticity Cx 0.49 to 0.65 and chromaticity Cy 0.38 to 0.50, and even more preferably chromaticity Cx 0.50 to 0.60 and chromaticity Cy 0.40 to 0.45. In this way, it is easy to obtain a wavelength conversion member with an amber color that is yellow to red. Furthermore, chromaticity Cz is preferably 0 to 0.15, more preferably 0 to 0.10, and even more preferably 0 to 0.05. In this case, light transmission in the excitation band of the inorganic phosphor can be more effectively suppressed, making it easier to use as a component of automotive lighting such as turn signals.

[0090] The chromaticity of the emitted light from the light-emitting device of the present invention is preferably a chromaticity Cx of 0.45 to 0.65 and a chromaticity Cy of 0.35 to 0.50, more preferably a chromaticity Cx of 0.49 to 0.65 and a chromaticity Cy of 0.38 to 0.50, and even more preferably a chromaticity Cx of 0.50 to 0.60 and a chromaticity Cy of 0.40 to 0.45. This facilitates the production of a light-emitting device with an amber color, which is yellow to red. Furthermore, the chromaticity Cz is preferably 0 to 0.15, more preferably 0 to 0.1, and even more preferably 0 to 0.05. In this case, transmission of light in the excitation band of the inorganic phosphor can be more effectively suppressed. In the first and second embodiments, the chromaticity of the emitted light from the light-emitting device can be calculated from the energy distribution spectrum of light measured by placing a wavelength conversion member directly above a light source with an excitation peak wavelength of 450 nm inside an integrating sphere and capturing the total luminous flux when the device is turned on.

[0091] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples.

[0092] (Examples 1 to 6) SiO in mass % ２ 50%, Al２ O ３ 6%, B ２ O ３ Glass powder (softening point: 850°C, thermal expansion coefficient: 68.0 × 10) having a composition of 5% MgO, 12% CaO, 25% BaO, and 2% ZnO －７ / °C, average particle size: 2.5 μm) and α-SiAlON were added in the proportions shown in Table 1 to obtain mixed powders. α-SiAlON is a phosphor that emits yellow to red, so-called amber fluorescence, with an excitation wavelength of 250 nm to 500 nm and an emission peak wavelength of 600 nm.

[0093]

[0094] The obtained mixed powder was pressure-molded in a mold to prepare a preform having a diameter of 20 mm and a thickness of 3 mm. The preform was fired at 850° C. to prepare a base material. A plate-shaped base material measuring 12 mm × 12 mm × 0.3 mm was cut out from the base material, and the plate-shaped base material was lapped and polished using a double-sided polisher to obtain a wavelength conversion member main body having a thickness of 150 μm.

[0095] On one main surface of the obtained wavelength conversion member body, TiO ２ layer and SiO ２ A wavelength conversion member was obtained by forming a dielectric multilayer film (filter layer) by sputtering, which was composed of a total of 20 layers of alternating layers. Figure 5 shows a graph representing the spectral transmittance curve at an incident angle of 0° when the same dielectric multilayer films (filter layers) as those stacked in Examples 1 to 6 were formed on a glass substrate with a thickness of 0.5 mm. Table 2 also shows the configuration of the dielectric multilayer film. This shows that the transmission of light at the excitation wavelength of the inorganic phosphor is suppressed. It also shows that light at the emission wavelength of the inorganic phosphor is more transmitted.

[0096]

[0097] (Examples 7 and 8 and Comparative Examples 1 to 3) Wavelength conversion members were obtained in the same manner as in Examples 1 to 6, except that mixed powders were obtained in the proportions shown in Tables 1 and 3 and that the wavelength conversion member body was used alone as the wavelength conversion member without forming a dielectric multilayer film.

[0098]

[0099] Next, each wavelength conversion element was placed under a light source with an excitation peak wavelength of 450 nm. The light emitted from the underside of the wavelength conversion element was introduced into an integrating sphere and then guided to a spectrometer (Ocean Photonics, USB2000) whose wavelength was calibrated using a standard light source, and the light energy distribution spectrum was measured. The LED and wavelength conversion element were spaced 5 mm apart, and the wavelength conversion element was placed so as to cover the 2 mm diameter hole at the top of the integrating sphere. The wavelength conversion element was also placed so that the dielectric multilayer film was on the side opposite the light source with an excitation peak wavelength of 450 nm (the exit surface). The results are shown in Figures 6 to 8.

[0100] As shown in Figures 6 to 8, in Examples 1 to 6, in which a dielectric multilayer film was formed, the transmission of light at the excitation wavelength of the inorganic phosphor was effectively suppressed, and light at the emission wavelength of the inorganic phosphor was more transmitted. On the other hand, in Comparative Examples 1 to 3, the transmission of light at the excitation wavelength of the inorganic phosphor, which is blue light, was not sufficiently suppressed. Furthermore, Figure 6 shows that the excitation light reflected by the dielectric multilayer film returns to the inside of the wavelength conversion member, making it easier for the phosphor particles to be excited, resulting in increased fluorescence intensity. Furthermore, in Examples 7 and 8, the wavelength conversion member contains a high inorganic phosphor content of 30% by mass or more, and thus the transmission of light at the excitation wavelength of the inorganic phosphor was effectively suppressed.

[0101] (Calculation of chromaticity Cx, Cy, Cz) Next, the chromaticity Cx, Cy, Cz of the obtained wavelength conversion member were calculated from the light energy distribution spectrum obtained earlier. The chromaticity Cx, Cy, Cz was determined by integrating the above spectrum using the CIE 1931 2-deg, x(_), y(_), z(_) color matching functions to find the tristimulus values ​​XYZ. From these tristimulus values ​​XYZ, chromaticity Cx = X / (X + Y + Z), chromaticity Cy = Y / (X + Y + Z), and chromaticity Cz = Z / (X + Y + Z) were calculated. The results are shown in FIG. 9, Table 1, and Table 3.

[0102] 9, it was found that the chromaticity Cx and Cy of Examples 1 to 8 were within the range of 0.45 to 0.65 for chromaticity Cx and 0.35 to 0.50 for chromaticity Cy, which are indicators of amber color. On the other hand, it was found that in Comparative Examples 1 to 3, the transmission of light of the excitation wavelength was not sufficiently suppressed, and therefore the light of the excitation wavelength and the light of the emission wavelength were combined, resulting in a whitish color.

[0103] (Luminous Flux Value) The luminous flux value of the obtained wavelength conversion member was calculated by multiplying the above-mentioned light energy distribution spectrum by the standard relative luminous efficiency, integrating the result over wavelengths of 380 to 780 nm, and multiplying it by a conversion coefficient of 683. Thereafter, the relative luminous flux value of each sample was determined when the luminous flux value of Example 1 was set to 1.00. The results are shown in Tables 1 and 3 above.

[0104] (Example 9) A wavelength conversion member was obtained in the same manner as in Example 1, except that the thickness of the wavelength conversion member body was 120 μm, the content of the inorganic phosphor was 25 mass %, and the dielectric multilayer film was configured as shown in Table 4 below (total number of laminated layers of the dielectric multilayer film: 26).

[0105]

[0106] (Example 10) A wavelength conversion member was obtained in the same manner as in Example 1, except that the thickness of the wavelength conversion member body was 120 μm, the content of the inorganic phosphor was 25 mass %, and the dielectric multilayer film was configured as shown in Table 5 below (total number of laminated layers of the dielectric multilayer film: 26).

[0107]

[0108] Example 11 A wavelength conversion member was obtained in the same manner as in Example 1, except that the thickness of the wavelength conversion member body was 120 μm, the content of the inorganic phosphor was 25 mass %, and the dielectric multilayer film was configured as shown in Table 6 below (total number of laminated layers of the dielectric multilayer film: 26).

[0109]

[0110] Fig. 10 is a graph showing the spectral transmittance curve at an incident angle of 0° when the same dielectric multilayer film (filter layer) as used in Examples 9 to 11 is formed on a glass substrate with a thickness of 0.5 mm. For reference, Fig. 10 also shows the blue LED spectrum.

[0111] As shown in FIG. 10, the cut-on wavelength of the filter layer of Example 9 was 510 nm, the cut-on wavelength of the filter layer of Example 10 was 547 nm, and the cut-on wavelength of the filter layer of Example 11 was 567 nm.

[0112] Next, the light energy distribution spectrum (emission spectrum) of the wavelength conversion members obtained in Examples 9 to 11 was measured in the same manner as in Examples 1 to 8 and Comparative Examples 1 to 3. The results are shown in FIG.

[0113] 11, it can be seen that the filter layers of Examples 9 to 11 effectively suppress the transmission of light in the excitation band of the inorganic phosphor and transmit light of the emission wavelength of the inorganic phosphor. It can also be seen that the larger the cut-on wavelength of the filter layer, the more effectively the filter layer can suppress the transmission of light in the excitation band of the inorganic phosphor.

[0114] Example 12 A wavelength conversion member was obtained in the same manner as in Example 10, except that a mixture of α-SiAlON and SCASN (α-SiAlON:SCASN=90:10 by mass) was added as the phosphor powder so that the total content of the inorganic phosphor was 25 mass %. SCASN is a phosphor that emits red fluorescence, with an excitation band wavelength of 300 nm to 500 nm and an emission peak wavelength of 630 nm.

[0115] Example 13: Glass powder was mixed with SiO ２ 63%, Al ２ O ３ 6%, B ２ O ３ 8%, Li ２ O 2%, Na ２ O 5%, K ２ O 4%, BaO 7%, ZnO 4%, CeO ２A wavelength conversion member was obtained in the same manner as in Example 11, except that glass powder (softening point: 695°C, average particle size: 2.5 μm) having a composition of 1% was used, and a mixture of α-SiAlON and SCASN (α-SiAlON:SCASN = 90:10 in mass ratio) was added as the phosphor powder so that the total content of the inorganic phosphor was 17 mass%.

[0116] Next, the chromaticity Cx, Cy, Cz and luminous flux values ​​of the wavelength conversion members obtained in Examples 9 to 13 were measured in the same manner as in Examples 1 to 8 and Comparative Examples 1 to 3. The results are shown in Table 7 below. The luminous flux values ​​of the obtained wavelength conversion members were calculated by multiplying the above-mentioned light energy distribution spectrum by the standard relative luminous efficiency, and then the relative luminous flux value of each sample was determined when the luminous flux value of Example 10 was set to 1.00.

[0117]

[0118] The wavelength conversion member of the present invention is suitable as a component of general lighting such as white LEDs and special lighting (for example, projector light sources, vehicle lighting such as vehicle headlights and turn signals).

[0119] REFERENCE SIGNS LIST 1, 100 Wavelength conversion member 10 Wavelength conversion member body 11, 110 Inorganic matrix 12, 120 Inorganic phosphor 20 Filter layer 3 Light-emitting device 30 Light source 40 Dielectric multilayer film 41L Low refractive index layer 41H High refractive index layer L0 Light of excitation wavelength (excitation light) L1 Light of emission wavelength (fluorescence)

Claims

1. A wavelength conversion member comprising a wavelength conversion body in which an inorganic phosphor is dispersed in an inorganic matrix, and a filter layer provided on one surface of the wavelength conversion body, wherein the filter layer suppresses transmission of light in the excitation band of the inorganic phosphor, and transmits light of the emission peak wavelength of the inorganic phosphor.

2. The wavelength conversion member according to claim 1, characterized in that the excitation band of the inorganic phosphor is between 300 nm and 480 nm in wavelength, and the emission peak wavelength of the inorganic phosphor is 500 nm or more and 700 nm or less.

3. The wavelength conversion member according to claim 1 or 2, wherein the filter layer is a dielectric multilayer film.

4. The wavelength conversion member according to claim 3, characterized in that the total number of layers of the dielectric multilayer film is 10 or more.

5. The wavelength conversion member according to claim 1 or 2, characterized in that the inorganic phosphor contains at least one type selected from the group consisting of nitride phosphors and oxynitride phosphors.

6. The wavelength conversion member according to claim 1 or 2, characterized in that the inorganic matrix contains glass or ceramics.

7. The wavelength conversion member according to claim 1 or 2, characterized in that the wavelength conversion member is placed under a light source with an excitation peak wavelength of 450 nm, and the chromaticity calculated from the energy distribution spectrum of light measured by taking light emitted from the lower surface of the wavelength conversion member into an integrating sphere is a chromaticity Cx of 0.45 to 0.65 and a chromaticity Cy of 0.35 to 0.

50.

8. The wavelength conversion member according to claim 1 or 2, characterized in that the cut-on wavelength of the filter layer is 480 nm or more and 680 nm or less.

9. The wavelength conversion member according to claim 1 or 2, wherein the filter layer is disposed on the emission surface side of the wavelength conversion member.

10. The wavelength conversion member according to claim 9, wherein the filter layer also functions as a filter for cutting a part of the emission spectrum on the short wavelength side of the inorganic phosphor.

11. A wavelength conversion material comprising an inorganic phosphor dispersed in an inorganic matrix, the inorganic phosphor comprising at least one type selected from the group consisting of oxide phosphors, nitride phosphors, oxynitride phosphors, chloride phosphors, oxychloride phosphors, halide phosphors, aluminate phosphors and halophosphate chloride phosphors, and the content of the inorganic phosphor is 25 mass% or more.

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