Wavelength conversion member, sensing device, and ultraviolet rays detection device

Abstract

To provide a wavelength conversion member that can efficiently convert ultraviolet light into converted light having a longer wavelength and suppress leakage of the ultraviolet light to the outside.SOLUTION: A wavelength conversion member 1 converts ultraviolet light A into converted light B with a wavelength longer than the ultraviolet light A. The wavelength conversion member 1 includes: a wavelength conversion member body 2 that includes a first main surface 2a, on which the ultraviolet light A is incident, and a second main surface 2b, which faces the first main surface 2a and from which the converted light B is emitted, an inorganic matrix 4, and a phosphor 5 which is dispersed in the inorganic matrix 4 and converts the ultraviolet light A into the converted light B; and a functional film 3 which is provided on the second main surface 2b of the wavelength conversion member body 2, transmits the converted light B, and shields the ultraviolet light A.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a wavelength conversion member, and a sensing device and an ultraviolet detection device using the wavelength conversion member. [Background technology]

[0002] In recent years, the use of ultraviolet light has been considered for various applications such as UV cleaning, UV sterilization, and UV curing, and the development of devices using ultraviolet light has become increasingly popular. However, ultraviolet light cannot be detected by the human eye, so there is a problem that it is difficult to confirm the intensity and degree of deterioration of the ultraviolet light source. In addition, while gallium nitride (GaN) photodiodes (PDs) are known as modules for detecting ultraviolet light, they are expensive and therefore difficult to generalize.

[0003] Therefore, Patent Document 1 below proposes an ultraviolet detector that converts ultraviolet light into visible light using a wavelength conversion element and detects the amount of the converted visible light. The ultraviolet detector described in Patent Document 1 discloses fluorescent glass (glass doped with a fluorescent component in its composition) as a material that converts ultraviolet light into visible light. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] WO 00 / 11440 Summary of the Invention [Problem to be solved by the invention]

[0005] In a wavelength conversion member that converts ultraviolet light into light with a longer wavelength as in Patent Document 1, leakage of ultraviolet light as emitted light may cause deterioration of surrounding resin components, etc. On the other hand, when attempting to suppress leakage of ultraviolet light, the emission efficiency of the converted light may decrease.

[0006] An object of the present invention is to provide a wavelength conversion member that can efficiently convert ultraviolet light into converted light of a longer wavelength and that can suppress leakage of the ultraviolet light to the outside, as well as a sensing device and an ultraviolet detection device that use the wavelength conversion member. [Means for solving the problem]

[0007] Aspects of a wavelength conversion member, a sensing device, and an ultraviolet detection device that solve the above problems will be described below.

[0008] A wavelength conversion member according to a first aspect of the present invention is a wavelength conversion member that converts ultraviolet light into converted light having a longer wavelength than the ultraviolet light, and is characterized by comprising: an inorganic matrix having a first main surface on which the ultraviolet light is incident and a second main surface opposite the first main surface and from which the converted light is emitted; a wavelength conversion member body containing a phosphor dispersed in the inorganic matrix and converting the ultraviolet light into the converted light; and a functional film provided on the second main surface of the wavelength conversion member body and transmitting the converted light and blocking the ultraviolet light.

[0009] The wavelength conversion member of aspect 2 is preferably the same as that of aspect 1, in which the functional film is an ultraviolet absorbing film.

[0010] The wavelength conversion member of aspect 3 is the same as in aspect 2, but preferably, the ultraviolet absorbing film contains ZnO.

[0011] The wavelength conversion member of aspect 4 is preferably the same as that of aspect 2, in which the ultraviolet absorbing film is a film made of ZnO.

[0012] In the wavelength conversion member of aspect 5, in any one of aspects 2 to 4, the ultraviolet absorbing film preferably has a thickness of 0.1 μm or more and 50 μm or less.

[0013] The wavelength conversion member of aspect 6 is any one of aspects 1 to 5, and may further include a bandpass filter that selectively transmits ultraviolet light on the first main surface of the wavelength conversion member body.

[0014] The wavelength conversion member of aspect 7, in any one of aspects 1 to 6, preferably has a total light transmittance of 80% or less in the wavelength range of 250 nm to 365 nm.

[0015] In the wavelength conversion member of aspect 8, in any one of aspects 1 to 7, it is preferable that the converted light is visible light.

[0016] A sensing device according to aspect 9 of the present invention is characterized in that it comprises a wavelength conversion member according to any one of aspects 1 to 8, and a photodiode arranged on the second main surface side of the wavelength conversion member body and detecting the converted light emitted from the second main surface side of the wavelength conversion member body.

[0017] An ultraviolet detection device according to a tenth aspect of the present invention is characterized by comprising the sensing device of the ninth aspect and an ultraviolet light generating source arranged on the first main surface side of the wavelength conversion member body. Effect of the Invention

[0018] According to the present invention, it is possible to provide a wavelength conversion member that can efficiently convert ultraviolet light into converted light of a longer wavelength and that can suppress leakage of the ultraviolet light to the outside, as well as a sensing device and an ultraviolet detection device that use the wavelength conversion member. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic perspective view showing a wavelength conversion member according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic cross-sectional view of a portion taken along line XX in FIG. [Diagram 3]FIG. 3 is a schematic cross-sectional view showing a wavelength conversion member according to a second embodiment of the present invention. [Figure 4] FIG. 4 is a schematic cross-sectional view showing an ultraviolet detection device according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Preferred embodiments will be described below. However, the following embodiments are merely examples, and the present invention is not limited to the following embodiments. In addition, in each drawing, components having substantially the same functions may be referred to by the same reference numerals.

[0021] [Wavelength conversion material] (First embodiment) Fig. 1 is a schematic perspective view showing a wavelength conversion member according to a first embodiment of the present invention, and Fig. 2 is a schematic cross-sectional view of a portion taken along line XX in Fig. 1.

[0022] The wavelength conversion member 1 is a member that converts ultraviolet light A into converted light B having a longer wavelength than the ultraviolet light A. The wavelength conversion member 1 of this embodiment has a rectangular plate shape. However, the wavelength conversion member 1 may have a shape such as a substantially rectangular plate shape, a substantially circular plate shape, a polygonal plate shape, a sphere shape, a hemisphere shape, or a hemispherical dome shape, and the shape is not particularly limited.

[0023] The wavelength conversion member 1 includes a wavelength conversion member body 2 and a functional film 3. The wavelength conversion member body 2 has a first main surface 2a and a second main surface 2b that face each other. The first main surface 2a is a main surface onto which ultraviolet light A is incident. The second main surface 2b is a main surface from which converted light B is emitted.

[0024] The wavelength conversion material body 2 includes an inorganic matrix 4 and a phosphor (phosphor particles 5) dispersed in the inorganic matrix 4. The phosphor particles 5 are particles capable of converting ultraviolet light A into converted light B having a longer wavelength than the ultraviolet light A.

[0025] A functional film 3 is provided on the second main surface 2b of the wavelength conversion member body 2. The functional film 3 is a film that transmits the converted light B and blocks the ultraviolet light A. For example, the functional film 3 is a film that transmits visible light as the converted light B and blocks the ultraviolet light A. The converted light B is preferably visible light, but may be infrared light.

[0026] In this embodiment, as shown in Fig. 2, ultraviolet light A from a light source is incident on the wavelength conversion member 1. More specifically, the ultraviolet light A is incident on the wavelength conversion member body 2 from the first main surface 2a side. When the ultraviolet light A is irradiated onto phosphor particles 5 contained in the wavelength conversion member body 2, the ultraviolet light A is converted into converted light B having a longer wavelength than the ultraviolet light A. The converted light B passes through the second main surface 2b and functional film 3 of the wavelength conversion member body 2, and is emitted from the wavelength conversion member 1.

[0027] In the wavelength conversion member 1 of this embodiment, a functional film 3 that transmits converted light B and blocks ultraviolet light A is provided on the second main surface 2b of the wavelength conversion member main body 2, so that the ultraviolet light A can be efficiently converted into converted light B of a longer wavelength and the leakage of the ultraviolet light A to the outside can be suppressed.

[0028] Therefore, the wavelength conversion member 1 can emit the converted light B with high efficiency while suppressing deterioration of peripheral resin components, etc. Therefore, the wavelength conversion member 1 can improve the sensing sensitivity when used in, for example, a sensing device or an ultraviolet detection device that converts ultraviolet light A into visible light and detects the amount of the converted visible light.

[0029] The total light transmittance of the wavelength conversion member 1 at wavelengths of 250 nm to 365 nm is not particularly limited, but is preferably 80% or less, more preferably 70% or less, even more preferably 60% or less, even more preferably 50% or less, even more preferably 40% or less, even more preferably 30% or less, even more preferably 20% or less, and particularly preferably 10% or less. In this case, deterioration of peripheral resin members and the like can be further suppressed. The total light transmittance of the wavelength conversion member 1 at wavelengths of 250 nm to 365 nm may be 0%, but in reality, it is preferably 5% or more, more preferably 10% or more, and even more preferably 20% or more.

[0030] In particular, the total light transmittance of the wavelength conversion member 1 at wavelengths of 315 nm to 365 nm is not particularly limited, but is preferably 80% or less, more preferably 70% or less, even more preferably 60% or less, even more preferably 50% or less, even more preferably 40% or less, even more preferably 30% or less, and particularly preferably 20% or less. In this case, deterioration of peripheral resin members and the like can be further suppressed. The total light transmittance of the wavelength conversion member 1 at wavelengths of 315 nm to 365 nm may be 0%, but in reality it is preferably 5% or more, more preferably 10% or more, and even more preferably 20% or more.

[0031] The wavelength conversion member 1 of this embodiment comprises a wavelength conversion member main body 2 and a functional film 3. Therefore, even if the wavelength conversion member main body 2 alone is insufficient in blocking ultraviolet light A, for example, in the wavelength range of 315 nm to 365 nm, the functional film 3 can reliably suppress leakage of ultraviolet light A to the outside.

[0032] Furthermore, the total light transmittance of the wavelength conversion member 1 at wavelengths of 400 nm to 700 nm is not particularly limited, but is preferably 81% or more, more preferably 85% or more, and even more preferably 90% or more. In this case, when the wavelength conversion member 1 is used in the above-mentioned sensing device or ultraviolet detection device, the sensing sensitivity can be further improved. Furthermore, the total light transmittance of the wavelength conversion member 1 at wavelengths of 400 nm to 700 nm may be 100%, but in reality it is preferably 99% or less, more preferably 98% or less, and even more preferably 97% or less.

[0033] The above-mentioned total light transmittance of the wavelength conversion member 1 is the transmittance when light is incident on the first main surface 2a of the wavelength conversion member main body 2 and is emitted from the main surface 3a of the functional film 3 opposite the wavelength conversion member main body 2, as shown in FIG.

[0034] The thickness of the wavelength conversion member 1 is not particularly limited, but can be, for example, 0.01 mm or more and 2 mm or less, preferably 0.05 mm or more, more preferably 0.1 mm or more, preferably 1.5 mm or less, and more preferably 1.2 mm or less.

[0035] Each member of the wavelength conversion member 1 will be described in detail below.

[0036] Wavelength conversion member body; The areas of the first main surface 2a and the second main surface 2b of the wavelength conversion member body 2 are not particularly limited, but are, for example, 0.1 mm 2 More than 10000mm 2 The areas of the first main surface 2a and the second main surface 2b of the wavelength conversion member body 2 may be the same or different. The shape of the wavelength conversion member body 2 is not particularly limited, and may be, for example, a substantially rectangular plate shape, a substantially circular plate shape, a polygonal plate shape, a sphere shape, a hemisphere shape, or a hemispherical dome shape.

[0037] The thickness of the wavelength conversion member body 2 is not particularly limited, but can be, for example, 0.01 mm or more and 2 mm or less, preferably 0.05 mm or more, more preferably 0.1 mm or more, preferably 1.5 mm or less, and more preferably 1.2 mm or less.

[0038] The wavelength conversion member body 2 includes an inorganic matrix 4 and phosphor particles 5 dispersed in the inorganic matrix 4.

[0039] The total light transmittance of the inorganic matrix 4 at wavelengths of 250 nm to 365 nm is not particularly limited, but is preferably 10% or more, more preferably 30% or more, even more preferably 50% or more, and is preferably 80% or less, more preferably 79% or less, and even more preferably 78% or less. When the total light transmittance of the inorganic matrix 4 is equal to or more than the lower limit, the emission efficiency of the converted light B can be further increased. When the total light transmittance of the inorganic matrix 4 is equal to or less than the upper limit, leakage of the ultraviolet light A to the outside can be further suppressed.

[0040] The inorganic matrix 4 is not particularly limited, and a glass matrix, a ceramic matrix, or the like can be used.

[0041] The glass matrix may contain, for example, in mole percent, 30% to 85% SiO2, 30% to 35% B2O, 30% to 25% Al2O, 0% to 10% Li2O+Na2O+K2O, and 0% to 45% MgO+CaO+SrO+BaO. The reason for limiting the glass composition in this way is explained below. In the following explanation of each component, "%" means "mol %" unless otherwise specified.

[0042] SiO2 is a component that forms a glass network, and has the effect of improving ultraviolet transmittance and devitrification resistance. It also has the effect of improving weather resistance and mechanical strength. The content of SiO2 is preferably 30% to 85%, more preferably 40% to 80%, further preferably 50% to 75%, and particularly preferably 55% to 70%. If the content of SiO2 is too low, it becomes difficult to obtain the above effects. On the other hand, if the content of SiO2 is too high, the sintering temperature becomes high, and the phosphor particles 5 are likely to deteriorate during the production of the wavelength conversion member body 2. In addition, the flowability of the glass powder during firing is poor, and air bubbles are likely to remain in the glass matrix after firing. Furthermore, there is a risk that the ultraviolet transmittance becomes too high.

[0043] B2O3 is a component that lowers the melting temperature and improves the melting property. In addition, B2O3 does not reduce the ultraviolet transmittance very much, and has the effect of suppressing ultraviolet absorption by alkali metal components and alkaline earth metal components. The content of B2O3 is preferably 0% to 35%, more preferably 0% to 20%, even more preferably 1% to 15%, still more preferably 2% to 10%, particularly preferably 3% to 8%, and most preferably 4% to 7%. If the content of B2O3 is too high, the weather resistance is likely to decrease. In addition, there is a risk that the ultraviolet transmittance becomes too high.

[0044] Al2O3 is a component that improves weather resistance and mechanical strength. In addition, like B2O3, it has the effect of suppressing ultraviolet absorption by alkali metal components and alkaline earth metal components. The content of Al2O3 is preferably 0% to 25%, more preferably 0.1% to 20%, further preferably 1% to 10%, and particularly preferably 2% to 8%. If the content of Al2O3 is too high, the melting property tends to decrease. In addition, there is a risk that the ultraviolet transmittance becomes too high.

[0045] Li2O, Na2O and K2O are components that lower the melting temperature to improve the melting property and also lower the softening point. However, if the content of these components is too high, the weather resistance is likely to decrease, and the emission intensity is likely to decrease over time due to irradiation with ultraviolet light A, which is the excitation light. Therefore, the content of Li2O+Na2O+K2O is preferably 0% to 10%, more preferably 0% to 5%, even more preferably 0% to 3%, even more preferably 0% to 2%, particularly preferably 0% to 1%, and it is most preferable that they are not contained. In addition, the content of each of the components Li2O, Na2O and K2O is preferably 0% to 7%, more preferably 0% to 5%, even more preferably 0% to 3%, even more preferably 0% to 2%, particularly preferably 0% to 1%, and it is most preferable that they are not contained.

[0046] As described later, when CeO2 is contained in the glass composition, even if Li2O, Na2O or K2O is contained, the decrease in the emission intensity due to irradiation with ultraviolet light A over time can be suppressed. Therefore, when CeO2 is contained in the glass composition, Li2O, Na2O or K2O may be actively contained. In this case, the content (total amount) of Li2O, Na2O and K2O is preferably 0.1% to 7%, more preferably 1% to 6.5%, and even more preferably 2% to 6%. Moreover, the content of Li2O, Na2O and K2O is preferably 0% to 7%, more preferably 0.1% to 5%, still more preferably 0.5% to 4%, and particularly preferably 1% to 3%. It is preferable to use two or more kinds of Li2O, Na2O and K2O, particularly three kinds, in a mixture. Specifically, it is preferable to contain Li2O, Na2O and K2O in an amount of 0.1% or more, more preferably 0.5% or more, and particularly 1% or more. In this way, the mixed alkali effect can be achieved to efficiently lower the softening point while suppressing the decrease in luminous intensity over time. In addition, the mixed alkali effect can be easily achieved by making the contents of each alkali oxide equal.

[0047] MgO, CaO, SrO and BaO are components that lower the melting temperature, improve the melting property and lower the softening point. Unlike alkali metal components, these components do not affect the decrease in the emission intensity of the wavelength conversion member 1 over time. The content of MgO+CaO+SrO+BaO is preferably 0% to 45%, more preferably 1% to 45%, even more preferably 5% to 40%, still more preferably 10% to 35%, and particularly preferably 20% to 33%. If the content of MgO+CaO+SrO+BaO is too small, the softening point is difficult to decrease. On the other hand, if the content of MgO+CaO+SrO+BaO is too large, the weather resistance is likely to decrease. The content of each of MgO, CaO, SrO and BaO is preferably 0% to 35%, more preferably 0.1% to 33%, and still more preferably 1% to 30%. If the content of these components is too large, the weather resistance tends to decrease.

[0048] ZnO is a component that lowers the melting temperature and improves melting properties. ZnO is also a component that lowers the ultraviolet transmittance of the glass matrix. The content of ZnO is preferably 0% to 15%, more preferably 0% to 10%, even more preferably 0% to 5%, particularly preferably 0.1% to 4.5%, and most preferably 1% to 4%. If the content of ZnO is too high, the weather resistance tends to decrease. In addition, phase separation occurs, lowering the transmittance, and as a result, the emission intensity tends to decrease.

[0049] CeO2 is a component that reduces the ultraviolet light transmittance of the glass matrix. By including CeO2, it is possible to further suppress leakage of ultraviolet light A to the outside of the wavelength conversion member 1. CeO2 also has the effect of suppressing the decrease in luminous intensity over time caused by Li2O, Na2O or K2O. The content of CeO2 is preferably 0% to 10%, more preferably 0.001% to 10%, even more preferably 0.001% to 5%, still more preferably 0.01% to 3%, particularly preferably 0.05% to 1%, and most preferably 0.1% to 0.5%. If the content of CeO2 is too high, the visible light transmittance of the glass matrix decreases, and the luminous intensity tends to decrease.

[0050] In addition to the above components, various components can be contained within a range that does not impair the effects of the present invention. For example, P2O5, La2O3, Ta2O5, TeO2, TiO2, Nb2O5, Gd2O3, Y2O3, Sb2O3, SnO2, Bi2O3, As2O3, and ZrO2 may be contained in an amount of preferably 15% or less, more preferably 10% or less, and even more preferably 5% or less, and a total amount of 30% or less. F can also be contained. Since F has an effect of lowering the softening point, by containing it instead of an alkali metal component, which is one of the causes of color center formation, it is possible to suppress the decrease in emission intensity over time while maintaining a low softening point. The content of F is preferably 0% to 10%, more preferably 0% to 8%, and even more preferably 0.1% to 5% in anion %.

[0051] In addition to the above, the glass matrix may be, for example, SiO2-B2O3-RO-based glass (RO represents MgO, CaO, SrO, BaO) based glass, SiO2-B2O3-R2O (R2O represents Li2O, Na2O, K2O) based glass, SiO2-B2O3-Al2O3-based glass, SiO2-B2O3-R2O-Al2O3-based glass, SiO2-B2O3-ZnO-based glass, ZnO-B2O3-based glass, or SnO-P2O5-based glass.

[0052] If it is desired to fire the material at a low temperature, then ZnO-B2O3-based glass or SnO-P2O5-based glass, whose softening point can be lowered relatively easily, can be selected as the glass matrix. If it is desired to improve the weather resistance of the luminescent color conversion member (wavelength conversion member 1), then SiO2-B2O3-RO-based glass, SiO2-B2O3-R2O-based glass, SiO2-B2O3-Al2O3-based glass, SiO2-B2O3-R2O-Al2O3-based glass or SiO2-B2O3-ZnO-based glass can be selected as the glass matrix.

[0053] The softening point of the glass matrix is ​​preferably 600°C or higher, more preferably 630°C or higher, and even more preferably 650°C or higher. If the softening point of the glass matrix is ​​too low, the mechanical strength and weather resistance are likely to decrease. On the other hand, if the softening point of the glass matrix is ​​too high, the sintering temperature is also high, and the phosphor particles 5 are likely to deteriorate in the firing step during production. Therefore, the softening point of the glass matrix is ​​preferably 1100°C or lower, more preferably 1050°C or lower, and even more preferably 1000°C or lower.

[0054] The average particle diameter D of the glass powder, which is the raw material of the glass matrix, is 50 is preferably 100 μm or less, more preferably 50 μm or less, further preferably 20 μm or less, and particularly preferably 10 μm or less. 50 If the average particle diameter D of the glass powder is too large, air bubbles are likely to remain in the glass matrix after firing in the obtained wavelength conversion member 1, and the light extraction efficiency of the wavelength conversion member 1 may decrease. 50 The lower limit of is not particularly limited, but is preferably 0.1 μm or more, more preferably 1 μm or more, and further preferably 2 μm or more, taking into consideration production costs and ease of handling. In this specification, the average particle size is the average particle size D measured by a laser diffraction particle size distribution analyzer. 50 This refers to the following.

[0055] Examples of ceramics that form the ceramic matrix include Al2O3, MgO, and AlN.

[0056] The phosphor particles 5 are not particularly limited, and may be any that emits fluorescence with a longer wavelength than the ultraviolet light A when irradiated with ultraviolet light A with a wavelength of 200 nm to 380 nm, more preferably emits fluorescence of 400 nm or more, even more preferably emits fluorescence of 450 nm or more, and particularly preferably emits fluorescence in the visible range (for example, wavelength of 500 nm to 600 nm). However, the phosphor particles 5 may also be any that emits fluorescence in the infrared range (for example, wavelength of 780 nm to 30,000 nm) when irradiated with ultraviolet light A with a wavelength of 200 nm to 380 nm.

[0057] Specifically, examples of the phosphor particles 5 include oxide phosphors, nitride phosphors, oxynitride phosphors, chloride phosphors, oxychloride phosphors, halide phosphors, aluminate phosphors, and halophosphate chloride phosphors.

[0058] Among them, the phosphor particles 5 are garnet phosphors, particularly Lu3Al5O 12 : Ce and sialon phosphors, especially Si 6-z Al z O z N 8-z :Eu(0 <z<4.2)(β-SiAlON:Eu)、La3Si6N 11 :Ce, (Sr,Ca)AlSiN3:Eu is preferable because it can efficiently convert ultraviolet light A with a wavelength of 200 nm to 380 nm into fluorescence in the visible range. Furthermore, by using phosphor particles 5 that do not have an excitation band in the visible range, it is possible to convert only ultraviolet light A. In this case, even in an environment where visible light and ultraviolet light A are irradiated, it is possible to convert only ultraviolet light A, so that the emission efficiency can be further improved.

[0059] The average particle diameter of the phosphor particles 5 is preferably 1 μm or more, and more preferably 5 μm or more. If the average particle diameter of the phosphor particles 5 is too small, the quantum efficiency tends to be poor and the luminous intensity tends to decrease. On the other hand, if the average particle diameter of the phosphor particles 5 is too large, the dispersion state of the phosphor particles 5 in the inorganic matrix 4 tends to be poor, and the luminous color tends to be non-uniform. Therefore, the average particle diameter of the phosphor particles 5 is preferably 50 μm or less, and more preferably 25 μm or less.

[0060] The content of phosphor particles 5 in the wavelength conversion member body 2 is not particularly limited, but is preferably 0.01 vol% or more, more preferably 1 vol% or more, even more preferably 10 vol% or more, still more preferably 20 vol% or more, and is preferably 70 vol% or less, more preferably 65 vol% or less, and even more preferably 50 vol% or less. When the content of phosphor particles 5 is within the above range, the sensing sensitivity can be further improved when the wavelength conversion member 1 is used in the above-mentioned sensing device, ultraviolet detection device, etc.

[0061] As another embodiment of the inorganic matrix 4 and the phosphor particles 5 dispersed in the inorganic matrix 4, the wavelength conversion member body 2 may be made of ceramics (ceramic phosphor) such as YAG ceramics.

[0062] Functional membranes; The functional film 3 may be provided on at least a part of the second main surface 2b of the wavelength conversion member body 2, or may be provided on the entire second main surface 2b of the wavelength conversion member body 2.

[0063] The functional film 3 is preferably provided on a portion having an area of ​​10% or more of the entire area of ​​the second main surface 2b of the wavelength conversion material body 2, more preferably on a portion having an area of ​​30% or more, and even more preferably on a portion having an area of ​​50% or more.

[0064] The thickness of the functional film 3 is not particularly limited, and is preferably 0.1 μm or more, more preferably 0.5 μm or more, even more preferably 1 μm or more, even more preferably 5 μm or more, even more preferably 10 μm or more, and is preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 20 μm or less. In this case, leakage of the ultraviolet light A to the outside can be more reliably suppressed.

[0065] The functional film 3 is not particularly limited, and for example, an ultraviolet ray absorbing film, an ultraviolet ray reflecting film, or other ultraviolet ray blocking film can be used.

[0066] As the ultraviolet absorbing film, for example, a film containing ZnO can be used. Among them, as the ultraviolet absorbing film, a film containing ZnO as a main component is preferable, and a film made of ZnO is more preferable.

[0067] In this specification, a film containing a material as a main component refers to a film containing 50% by mass or more of the material. In a film containing a material as a main component, the material is preferably contained in an amount of 80% by mass or more, and more preferably 90% by mass or more. Of course, a film containing a material as a main component may be a film containing 100% by mass of the material.

[0068] The ultraviolet absorbing film may contain other components. Examples of the other components include ceramic particles or metal particles. The content of the other components in the film may be, for example, 5% by mass or less, preferably 3% by mass or less, and more preferably 1% by mass or less, based on the total material of the film (100% by mass).

[0069] The ultraviolet absorbing film may be either an inorganic material film or an organic material film. Inorganic material films include, for example, TiO2 films, in addition to the above-mentioned ZnO film. Organic material films include, for example, benzotriazole-based ultraviolet absorbing agent films and benzophenone-based ultraviolet absorbing agent films.

[0070] The thickness of the ultraviolet absorbing film is not particularly limited, but is preferably 0.1 μm or more, more preferably 0.5 μm or more, and preferably 50 μm or less, more preferably 20 μm or less. In this case, leakage of ultraviolet light A to the outside can be more reliably suppressed.

[0071] The ultraviolet reflective film may be a dielectric multilayer film such as a bandpass filter. The ultraviolet reflective film may be a multilayer film made of, for example, oxide, nitride, fluoride, or the like. Specifically, the dielectric multilayer film may be a multilayer film including a configuration in which a low refractive index dielectric layer having a relatively low refractive index and a high refractive index dielectric layer having a relatively high refractive index are alternately stacked. The low refractive index dielectric layer may be formed of, for example, silicon oxide. The high refractive index dielectric layer may be formed of, for example, titanium oxide, niobium oxide, lanthanum oxide, tantalum oxide, zirconium oxide, or the like.

[0072] The number of low refractive index dielectric layers can be, for example, from 1 to 20. The thickness of the low refractive index dielectric layers can be, for example, from 10 nm to 200 nm.

[0073] The number of high refractive index dielectric layers can be, for example, from 1 to 20. The thickness of the high refractive index dielectric layers can be, for example, from 10 nm to 200 nm.

[0074] The total number of layers in the dielectric multilayer film can be, for example, 2 or more and 40 or less.

[0075] The thickness of the ultraviolet reflective film is not particularly limited, but is preferably 15 nm or more, more preferably 20 nm or more, and is preferably 5000 nm or less, more preferably 2000 nm or less. In this case, leakage of ultraviolet light A to the outside can be more reliably suppressed.

[0076] An example of a method for manufacturing the wavelength conversion member 1 will now be described.

[0077] Manufacturing method; First, the wavelength conversion material body 2 is prepared. For example, when the inorganic matrix 4 is a glass matrix, the wavelength conversion material body 2 can be manufactured by firing a mixture containing glass powder, which is the raw material of the glass matrix, and phosphor particles (phosphor powder), and cutting the obtained fired body to a desired size.

[0078] The firing temperature of the mixture of glass powder and phosphor powder is preferably within ±200° C. of the softening point of the glass powder, and more preferably within ±150° C. of the softening point of the glass powder. 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 phosphor component may be thermally deteriorated, resulting in a decrease in luminescence intensity.

[0079] The firing is preferably carried out in a reduced pressure atmosphere. Specifically, the pressure in the atmosphere during firing is preferably 1.013×10 5 The pressure is less than 1000 Pa, more preferably 1000 Pa or less, and further preferably 400 Pa or less. This reduces the amount of bubbles remaining in the wavelength conversion member body 2, and for the reasons mentioned above, improves the luminous intensity. 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 increase and decrease processes before and after the firing process being performed in an atmosphere other than a reduced pressure atmosphere (for example, atmospheric pressure).

[0080] Next, the functional film 3 is formed on the second main surface 2b of the wavelength conversion material body 2. For example, when the functional film 3 is a film containing ZnO, the functional film 3 can be formed by applying a zinc oxide precursor solution onto the second main surface 2b of the wavelength conversion material body 2 and baking it.

[0081] Before applying the zinc oxide precursor solution, it is desirable to previously clean the second main surface 2b of the wavelength conversion member body 2. Examples of the cleaning method include ultrasonic cleaning and UV cleaning.

[0082] The zinc oxide precursor solution may be, for example, a solution containing zinc octylate, zinc alkoxide, zinc acetate, zinc acetylacetonate, zinc lactate trihydrate, zinc salicylate trihydrate, zinc stearate, etc. These zinc compounds may be used alone or in combination of two or more.

[0083] As the solvent constituting the zinc oxide precursor solution, for example, ethanol, n-propanol, n-butanol, n-pentanol, n-hexanol, isoamyl alcohol, 2-methoxyethanol, or 2-ethoxyethanol can be used. Furthermore, as the solvent, a diketone compound or a ketoester compound can be used. For example, as the solvent, acetylacetone, diacetyl, benzoylacetone, benzyl, 1-phenylbutane-1,2-dione, phenylacetylacetone, phenylbenzoylacetone, ethyl-phenyl-diketone, or 1-phenyl-1,2-butadione can be used. These solvents may be used alone or in combination of two or more.

[0084] The concentration of the zinc compound, such as zinc acetylacetonate, in the zinc oxide precursor solution can be, for example, 0.1 M or more and 1.0 M or less.

[0085] The zinc oxide precursor solution can be applied, for example, by spin coating. The rotation speed in the spin coating can be, for example, 100 rpm or more and 1000 rpm or less. The rotation time at the rotation speed can be, for example, 10 seconds or more and 10 minutes or less.

[0086] The firing temperature can be, for example, from 100° C. to 400° C. The firing time can be, for example, from 10 minutes to 3 hours.

[0087] Furthermore, when the functional film 3 is the above-mentioned dielectric multilayer film or the like, it may be formed by sputtering or vapor deposition, and the method of forming the functional film 3 is not particularly limited.

[0088] Second embodiment FIG. 3 is a schematic cross-sectional view showing a wavelength conversion member according to a second embodiment of the present invention.

[0089] As shown in FIG. 3, in the wavelength conversion member 21, a bandpass filter 23 is provided on the first main surface 2a of the wavelength conversion member body 2. The bandpass filter 23 is a filter that selectively transmits ultraviolet light. More specifically, the bandpass filter 23 is a filter that transmits ultraviolet light A and absorbs or reflects visible light. By providing the bandpass filter 23 on the first main surface 2a of the wavelength conversion member body 2, when the wavelength conversion member 21 is used in an environment where visible light such as a fluorescent lamp is irradiated, even if phosphor particles 5 excited by visible light are used, it is possible to more reliably prevent the phosphor particles 5 from being excited to emit fluorescence.

[0090] As the characteristics of the bandpass filter 23, the total light transmittance of the bandpass filter 23 in the wavelength range of 250 nm to 380 nm is preferably 10% or more, more preferably 50% or more, and even more preferably 80% or more. The total light transmittance of the bandpass filter 23 in the wavelength range of 380 nm to 780 nm is preferably 50% or less, more preferably 25% or less, and even more preferably 10% or less. The total light transmittance of the bandpass filter 23 in the wavelength range of 400 nm to 700 nm is preferably 30% or less, more preferably 10% or less, and even more preferably 5% or less. The total light transmittance of the bandpass filter 23 in the wavelength range of 420 nm to 600 nm is preferably 10% or less, more preferably 5% or less, and even more preferably 1% or less.

[0091] The bandpass filter 23 may be made of glass (glass plate). Specifically, the bandpass filter 23 may be made of ultraviolet transmitting, visible absorbing glass containing an element that absorbs visible light. Examples of elements that absorb visible light include Ni, Co, Ti, and the like. These are usually included in the glass composition as components such as NiO, CoO, and TiO2. Among them, NiO and CoO are preferable because they have relatively low absorption of ultraviolet light A and can absorb visible light. The total content (mass %) of NiO, CoO, and TiO2 in the glass composition is preferably 1% to 25%, more preferably 3% to 20%, and even more preferably 5% to 15%. If the content of these components is too low, sufficient visible light absorption performance may be difficult to obtain. On the other hand, if the content of these components is too high, vitrification may be difficult. The content of one of NiO, CoO and TiO2, and the total content of the two, is preferably 1% to 25%, more preferably 3% to 20%, and further preferably 5% to 15%.

[0092] When the bandpass filter 23 is made of glass, its thickness is preferably 0.2 mm to 3.0 mm, more preferably 0.3 mm to 2.0 mm, and further preferably 0.4 mm to 1.0 mm. If the thickness of the bandpass filter 23 is too small, it tends to be difficult to obtain sufficient visible light absorption performance. In addition, the mechanical strength of the bandpass filter 23 tends to be insufficient. On the other hand, if the thickness of the bandpass filter 23 is too large, it tends to be difficult to miniaturize the wavelength conversion member 21.

[0093] A dielectric multilayer film that reflects visible light (for example, a dielectric multilayer film formed on the surface of a glass plate) can also be used as the bandpass filter 23. The dielectric multilayer film has a configuration in which low-refractive index dielectric layers with a relatively low refractive index and high-refractive index dielectric layers with a relatively high refractive index are alternately laminated. The low-refractive index dielectric layers can be formed of, for example, silicon oxide. The high-refractive index dielectric layers can be formed of, for example, titanium oxide, niobium oxide, lanthanum oxide, tantalum oxide, hafnium oxide, zirconium oxide, or the like. However, since the reflectance of visible light in the dielectric multilayer film changes depending on the angle of incidence, there is a risk that sufficient filtering function cannot be obtained in an environment in which visible light is incident from a direction other than perpendicular to the filter surface. On the other hand, if ultraviolet-transmitting visible-absorbing glass is used, such a problem is unlikely to occur, and the desired bandpass function can be easily obtained. The ultraviolet-transmitting visible-absorbing glass and the dielectric multilayer film may be used in combination. In this case, the decrease in visible light absorption performance that occurs when the thickness of the ultraviolet-transmitting, visible-light-absorbing glass is reduced can be compensated for by the dielectric multilayer film, so that the wavelength conversion member 21 can be made smaller by reducing the thickness of the bandpass filter 23.

[0094] In the wavelength conversion member 21 of this embodiment, a functional film 3 that transmits converted light B and blocks ultraviolet light A is provided on the second main surface 2b of the wavelength conversion member body 2, so that the ultraviolet light A can be efficiently converted into converted light B of a longer wavelength and the leakage of the ultraviolet light A to the outside can be suppressed.

[0095] Therefore, the wavelength conversion member 21 can emit the converted light B with high efficiency while suppressing deterioration of peripheral resin components, etc. Therefore, the wavelength conversion member 21 can improve the sensing sensitivity when used in, for example, a sensing device or an ultraviolet detection device that converts ultraviolet light A into visible light and detects the amount of the converted visible light.

[0096] Although not shown, the functional film 3 may also be provided on the side surface 2c of the wavelength conversion member body 2. In this way, leakage of the ultraviolet light A to the outside can be more reliably suppressed, and deterioration of peripheral resin members and the like can be more reliably suppressed.

[0097] [Sensing devices and ultraviolet detection devices] FIG. 4 is a schematic cross-sectional view showing an ultraviolet detection device according to one embodiment of the present invention.

[0098] The ultraviolet detection device 30 includes a light source 40 and a sensing device 31. An ultraviolet light source having an intensity at a wavelength of 250 nm to 380 nm can be used as the light source 40. As such an ultraviolet light source, for example, a UV LED, a low pressure mercury lamp, a high pressure mercury lamp, a deuterium lamp, or the like can be used.

[0099] The sensing device 31 includes a wavelength conversion member 1 and a detector 50. The wavelength conversion member 1 may be one described in the section on wavelength conversion members. The detector 50 may be a photodiode that detects the converted light B emitted from the second main surface 2b side of the wavelength conversion member body 2. Examples of the photodiode include a Si photodiode and a Ge photodiode.

[0100] In this embodiment, as shown in FIG. 4, ultraviolet light A from a light source 40 is incident on the wavelength conversion member 1. More specifically, the ultraviolet light A is incident on the wavelength conversion member body 2 from the first main surface 2a side. When the ultraviolet light A is irradiated onto phosphor particles 5 contained in the wavelength conversion member body 2, the ultraviolet light A is converted into converted light B having a longer wavelength than the ultraviolet light A. The converted light B passes through the second main surface 2b and functional film 3 of the wavelength conversion member body 2, and is emitted from the wavelength conversion member 1. The converted light B emitted from the wavelength conversion member 1 can be monitored by a detector 50.

[0101] The sensing device 31 and the ultraviolet detection device 30 of this embodiment include the wavelength conversion member 1, and therefore can suppress leakage of the ultraviolet light A to the outside, and can suppress deterioration of peripheral resin members and the like. Furthermore, the sensing device 31 and the ultraviolet detection device 30 of this embodiment can efficiently convert the ultraviolet light A into converted light B of a longer wavelength, and can therefore improve the sensitivity of sensing. The sensing device 31 and the ultraviolet detection device 30 can detect even weak light noiselessly, and can also check for minute deterioration of the light source 40 (ultraviolet light generating source).

[0102] The present invention will be described in more detail below with reference to specific examples. The present invention is not limited to the following examples, and can be modified as appropriate within the scope of the present invention.

[0103] Example 1 Fabrication of wavelength conversion member body; The glass powder used as the glass matrix was a glass powder (softening point: 700°C, thermal expansion coefficient: 41.9×10) with a composition of SiO2 68%, Al2O3 4%, B2O3 19%, Na2O 7%, K2O 1%, and F21% by mass. -7 / °C, average particle size: 2.5 μm) was prepared.

[0104] The prepared glass powder was 11 :Ce 3+ Phosphor particles (peak fluorescence wavelength: 538 nm) were mixed and fired at 750° C. to obtain a sintered body. The phosphor particles were mixed so that the content in the wavelength conversion material body was 0.1 volume %. The sintered body was processed to produce a rectangular plate-shaped wavelength conversion material body with a length of 30 mm, a width of 30 mm, and a thickness of 0.3 mm.

[0105] Formation of functional membranes; First, one main surface of the wavelength conversion member body was cleaned. Specifically, the one main surface of the wavelength conversion member body was wiped with a cloth soaked in isopropyl alcohol, and then the wavelength conversion member body was immersed in isopropyl alcohol and ultrasonically cleaned for 2 sets for 10 minutes. After that, the wavelength conversion member body was ultrasonically cleaned for 10 minutes using an alkaline optical cleaner. Next, the wavelength conversion member body was immersed in boiled 2-propanol for 10 minutes. Next, a high-pressure mercury lamp (manufactured by Iwasaki Electric Co., Ltd., product number "QOL 25SY") was irradiated on the wavelength conversion member body for 30 minutes to complete the cleaning.

[0106] Next, a zinc oxide precursor solution was applied by spin coating to one of the main surfaces of the wavelength conversion member body after cleaning. -4 mol acetylacetone 5.33 x 10 -4 mol, and 2-methoxyethanol 5.63 x 10 -3 mol was stirred overnight on a hot stirrer at 50°C and 500 rpm (concentration of zinc acetylacetonate in zinc oxide precursor solution: 0.350M). Spin coating was performed for 60 seconds at a rotation speed of 1000 rpm using a spin coater (manufactured by Kyoei Semiconductor Co., Ltd., product number "SPINNER-1H-3"). Next, the wavelength conversion member body after spin coating was baked under atmospheric conditions at 250°C and 1 hour. In this manner, a ZnO film (thickness: 1 μm) was formed as a functional film on one main surface of the wavelength conversion member body, and a wavelength conversion member was produced.

[0107] Comparative Example 1 A wavelength conversion member was produced in the same manner as in Example 1, except that a ZnO film was not formed as a functional film.

[0108] [evaluation] The wavelength conversion members produced in Example 1 and Comparative Example 1 were irradiated with UVLED (wavelength 265 nm), and a Si photodiode with a light receiving portion sealed with epoxy resin was placed on the emission surface side to confirm whether the converted light of the UVLED (wavelength 265 nm) could be detected. The Si photodiode is a diode capable of detecting light with a wavelength of 350 nm to 1000 nm.

[0109] Further, the wavelength conversion members produced in Example 1 and Comparative Example 1 were irradiated with UV LED (wavelength 265 nm) continuously for 500 hours, and an acrylic test piece was placed 10 mm away from the exit surface side to evaluate the presence or absence of deterioration of the test piece. Note that, in the wavelength conversion member of Example 1, the main surface opposite to the functional film of the wavelength conversion member was used as the entrance surface, and the surface on which the functional film was provided was used as the exit surface.

[0110] The evaluation of the presence or absence of deterioration was performed by visually comparing the test pieces before and after irradiation with UV LED (wavelength 265 nm) in each of Example 1 and Comparative Example 1.

[0111] (Evaluation Results) In Example 1, it was confirmed that the converted light by the wavelength conversion member could be detected, and that the wavelength conversion member could efficiently convert the ultraviolet light into converted light of a longer wavelength. In addition, no change was observed in the test piece of Example 1 before and after the test, and it was confirmed that the leakage of ultraviolet light to the outside could be suppressed.

[0112] On the other hand, in Comparative Example 1, although the converted light by the wavelength conversion member could be detected, the test piece of Comparative Example 1 turned yellow and deteriorated. Thus, in Comparative Example 1, ultraviolet light leaked to the outside. [Explanation of symbols]

[0113] 1, 21...Wavelength conversion material 2…Wavelength conversion member body 2a…First main surface 2b…Second main surface 2c…side 3. Functional membrane 3a…main surface 4…Inorganic matrix 5...Phosphor particles 23...Bandpass filter 30...Ultraviolet light detection device 31…Sensing device 40...Light source 50…Detector A...Ultraviolet light B…Converted light

Claims

1. A wavelength conversion member that converts ultraviolet light into converted light having a longer wavelength than the ultraviolet light, a wavelength conversion member body including an inorganic matrix having a first main surface on which the ultraviolet light is incident and a second main surface opposed to the first main surface and from which the converted light is emitted, and a phosphor dispersed in the inorganic matrix and configured to convert the ultraviolet light into the converted light; a functional film provided on the second main surface of the wavelength conversion member body, the functional film transmitting the converted light and blocking the ultraviolet light; A wavelength conversion member comprising:

2. The wavelength conversion member according to claim 1 , wherein the functional film is an ultraviolet absorbing film.

3. The wavelength conversion member according to claim 2 , wherein the ultraviolet absorbing film contains ZnO.

4. The wavelength conversion member according to claim 2 , wherein the ultraviolet absorbing film is a film made of ZnO.

5. The wavelength conversion member according to any one of claims 2 to 4, wherein the ultraviolet absorbing film has a thickness of 0.1 μm or more and 50 μm or less.

6. 5. The wavelength conversion member according to claim 1, further comprising a bandpass filter that selectively transmits ultraviolet light on the first main surface of the wavelength conversion member body.

7. The wavelength conversion member according to any one of claims 1 to 4, wherein the wavelength conversion member has a total light transmittance of 80% or less in the wavelength range of 250 nm to 365 nm.

8. The wavelength conversion member according to any one of claims 1 to 4, wherein the converted light is visible light.

9. A wavelength conversion member according to any one of claims 1 to 4, a photodiode disposed on the second main surface side of the wavelength conversion member body and configured to detect the converted light emitted from the second main surface side of the wavelength conversion member body; A sensing device comprising:

10. A sensing device according to claim 9 ; An ultraviolet light generating source disposed on the first main surface side of the wavelength conversion member body; An ultraviolet detection device comprising:

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