UV-c transmission glass and glass component

Abstract

Provided is a UV-C transmission glass that exhibits good fusibility, a low coefficient of thermal expansion, and excellent water resistance in a specific composition of aluminoborate-based glass. This UV-C transmission glass is characterized by comprising, in mass%, not less than 46.90% to less than 55.00% of SiO2, more than 27.00% to not more than 35.10% of B2O3, 6.90-12.00% of Al2O3, 0.90-8.00% of Li2O, 0.90-8.10% of Na2O, 0-5.10% of K2O, not less than 4.00% to less than 9.00% of R2O (where R2O represents the total of Li2O, Na2O, and K2O), 0-3.00% of MgO, 0-3.00% of CaO, 0-4.00% of SrO, 0-4.00% of BaO, not less than 0% to less than 5.00% of R'O (where R'O represents the total of MgO, CaO, SrO, and BaO), 0-1.00% of Sb2O3, more than 0.01% to not more than 1.00% of F, and 0.05-1.00% of Cl, and is characterized in that the mass ratio represented by (R2O+R'O) / (SiO2+B2O3+Al2O3) is less than 0.1.

Description

UV-C transparent glass and glass components

[0001] This invention relates to UV-C transparent glass and glass components.

[0002] Traditionally, low-pressure mercury lamps emitting ultraviolet light at 184.9 nm and 253.7 nm have been used as light sources for sterilization purposes. However, due to the Minamata Regulation on Mercury, an international treaty concluded in 2013, the manufacture, import, and export of mercury-containing products have been prohibited since 2021, with the exception of some exempted items. As a result, there has been growing interest in UV-C LEDs (deep ultraviolet LEDs) as an alternative to low-pressure mercury lamps, as they have a lower impact on the human body and the environment. Furthermore, the spread of COVID-19 has increased the need to disinfect objects touched by many people on the spot, and UV-C LEDs, which are easy to use and compact, have rapidly gained popularity as a new market.

[0003] However, while mercury lamps have an output of several watts to tens of watts per lamp, UV-C LEDs have an output of several milliwatts to tens of milliwatts per element. Therefore, UV-C LEDs are still in the development stage in terms of output. In the future, as the efficiency of electricity and light generation improves and the output of UV-C LEDs exceeds 100 mW, UV-C LEDs will have an extremely strong germicidal effect and will be able to be implemented in large UV-C devices that were previously handled by mercury lamps.

[0004] As UV-C LEDs become more powerful, durability is required for UV-C LED packages. UV-C LED packages utilize window components that have the shape of a flat plate or lens. The lens-shaped window component protects the UV-C LED chip from the outside air and also controls the light emitted from the UV-C LED, enabling efficient UV-C irradiation.

[0005] Quartz glass, which offers excellent UV-C transmittance and durability, has been considered suitable for use in the window components of UV-C LED packages. However, the manufacture of quartz glass requires melting the raw materials at temperatures above 2000°C. Furthermore, processing of quartz glass involves mechanical cutting and polishing from ingots. Therefore, quartz glass has problems with productivity and processability.

[0006] On the other hand, aluminoborosilicate glass has a lower melting temperature than quartz glass, and some varieties exhibit high transmittance over a wide wavelength range. Therefore, aluminoborosilicate glass can be useful as glass for UV-C LED packages.

[0007] For example, Patent Documents 1-4 disclose aluminoborosilicate glass that is transparent to ultraviolet light.

[0008] Japanese Patent Publication No. 4-342437, Japanese Patent Publication No. 2018-197190, Japanese Patent Publication No. 2012-140314, Japanese Patent Publication No. 2013-230952

[0009] From a productivity standpoint, good meltability is essential for UV-C transparent glass. However, the glass disclosed in Patent Document 1 has poor meltability, and its manufacture may require melting the raw materials at high temperatures. Furthermore, poor meltability can lead to poor bubble removal, potentially resulting in bubbles remaining inside the glass. In addition, the glass disclosed in Patent Document 2 has SiO as its main component. ２ It is considered particularly preferable to include 60 to 68% by mass of SiO ２ This may lead to poor meltability.

[0010] It is essential that UV-C transparent glass has a low coefficient of thermal expansion. For example, UV-C LED packages typically use aluminum nitride (AlN) or alumina (AlN) as housing materials, as these materials have high thermal conductivity. ２ O ３Ceramics such as () are used. Since the thermal conductivity of glass and ceramics is significantly different, when heat is applied to and joined with glass and ceramic casings, the temperature difference between the glass and the casing becomes large. Therefore, if the thermal expansion coefficient of the glass is high, distortion may occur in the glass, leading to the risk of breakage defects. However, Patent Documents 3 and 4 do not pay any attention to the thermal expansion coefficient.

[0011] Since UV-C transmitting glass is required to function as a sealing material that protects the chip of the UV-C LED from moisture in the outside air, etc., it is also important to have good water resistance. Also, if the water resistance of the glass is poor, the glass may react with water and become cloudy, resulting in a risk of poor UV-C permeability. However, Patent Documents 2 and 4 do not pay any attention to water resistance.

[0012] In view of the above, for UV-C transmitting glass, it is required to satisfy all the requirements of good fusibility, low thermal expansion coefficient, and excellent water resistance, especially by optimizing the composition.

[0013] Therefore, the present invention has been made in view of such a situation, and an object thereof is to provide a UV-C transmitting glass having good fusibility, low thermal expansion coefficient, and excellent water resistance in a specific composition of aluminoborosilicate glass. Another object of the present invention is to provide a glass component using the above-described UV-C transmitting glass.

[0014] As a result of intensive studies to achieve the above object, the present inventor has found that the above problems can be achieved in a specific composition of aluminoborosilicate glass, and has completed the present invention. The gist of the present invention for solving the above problems is as follows.

[0015] [1] In mass%, SiO ２ : 46.90% or more and less than 55.00%, B ２ O ３ : more than 27.00% and 35.10% or less, Al<00000O: 0.90% or more and 8.10% or less, K ２ O: 0% or more and 5.10% or less, R ２ O: 4.00% or more and less than 9.00% (however, R ２ O is Li ２ O, Na ２ O and K ２ The sum of O is shown.), MgO: 0% to 3.00%, CaO: 0% to 3.00%, SrO: 0% to 4.00%, BaO: 0% to 4.00%, R'O: 0% to less than 5.00% (however, R'O represents the sum of MgO, CaO, SrO and BaO), Sb ２ O ３ Contains : 0% to 1.00%, F: over 0.01% to 1.00%, Cl: 0.05% to 1.00%, (R ２ O+R'O) / (SiO ２ +B ２ O ３ +Al ２ O ３ UV-C transparent glass characterized in that the mass ratio expressed as ) is less than 0.1.

[0016] [2] mean coefficient of linear expansion (α １００－３００℃ ) is 45 x 10 －７ / ℃ or higher 60 x 10 －７ The UV-C transparent glass described in [1] is below / ℃.

[0017] [3] The UV-C transmitting glass according to [1] or [2], wherein the internal transmittance at a wavelength of 265 nm in a glass thickness of 1 mm is 90% or more.

[0018] [4] A UV-C transparent glass according to any one of [1] to [3], wherein the glass transition temperature is 510°C or lower.

[0019] [5] A UV-C transparent glass according to any one of [1] to [4], wherein the glass piece is 20 mm x 10 mm x 10 mm, and when the glass piece is boiled in 1000 ml of pure water for 60 minutes, the weight loss before and after the boiling treatment is less than 0.1% by mass.

[0020] [6] UV-C transparent glass according to any of [1] to [5], for use in precision mold press molding.

[0021] [7] A glass component characterized by using UV-C transparent glass as a material, as described in any of [1] to [6].

[0022] According to the present invention, it is possible to provide UV-C transparent glass with good meltability, low thermal expansion coefficient, and excellent water resistance in a specific composition of aluminoborosilicate glass. Furthermore, according to the present invention, it is possible to provide glass components using the above-mentioned UV-C transparent glass.

[0023] (UV-C Transmitting Glass) Hereinafter, a UV-C transmitting glass according to one embodiment of the present invention (hereinafter sometimes referred to as "the glass of this embodiment") will be described in detail. The glass of this embodiment has a mass of SiO ２ : 46.90% or more and less than 55.00%, B ２ O ３ : more than 27.00% and less than 35.10%, Al ２ O ３ :6.90% or more and 12.00% or less, Li ２ O: 0.90% or more and 8.00% or less, Na ２ O: 0.90% or more and 8.10% or less, K ２ O: 0% or more and 5.10% or less, R ２ O: 4.00% or more and less than 9.00% (however, R ２ O is Li ２ O, Na ２ O and K ２ The sum of O is shown.), MgO: 0% to 3.00%, CaO: 0% to 3.00%, SrO: 0% to 4.00%, BaO: 0% to 4.00%, R'O: 0% to less than 5.00% (however, R'O represents the sum of MgO, CaO, SrO and BaO), Sb ２ O ３ One characteristic is that it contains 0% to 1.00%, F: more than 0.01% and 1.00%, and Cl: 0.05% to 1.00% (composition requirements). Furthermore, the glass of this embodiment is (R ２ O+R'O) / (SiO ２ +B ２ O ３+Al ２ O ３ One characteristic is that the mass ratio represented by (R) is less than 0.1. The glass of this embodiment was discovered by the inventor through repeated experiments, and satisfies the above composition requirements while (R ２ O+R'O) / (SiO ２ +B ２ O ３ +Al ２ O ３ By having a mass ratio less than 0.1, it is possible to provide UV-C transparent glass with good meltability, low thermal expansion coefficient, and excellent water resistance in a specific composition of aluminoborosilicate glass.

[0024] The reasons for the limitations on the range of each component in the composition requirements are as follows. Unless otherwise specified, "%" in relation to components refers to "mass percent".

[0025] <SiO ２ > SiO ２ SiO is an essential component in the glass of this embodiment and is the main component that forms the network structure of the glass. ２ It is a component that can lower the coefficient of thermal expansion and improve water resistance. Furthermore, SiO ２ It is a component that can improve devitrification resistance stability. However, SiO ２ If the content of is 55.00% or more, the viscosity of the glass melt will increase, and there is a risk that the meltability will decrease significantly. On the other hand, SiO ２ If the content of is less than 46.90%, there is a risk that the effect of lowering the coefficient of thermal expansion and the effect of improving water resistance will not be sufficiently obtained. Also, there is a risk that the effect of improving devitrification resistance stability will not be sufficiently obtained. For this reason, in the glass of this embodiment, SiO ２ The content of was set to be in the range of 46.90% or more and less than 55.00%. From a similar viewpoint, the SiO in the glass of this embodiment ２ The content of is preferably 47.00% or more, and preferably 54.90% or less.

[0026] <B ２ O ３ > B ２ O ３In the optical glass of this embodiment, SiO ２ is a component that forms the network structure of the glass in the same way as SiO. B ２ O ３ is a component that can reduce the viscosity of the glass melt without changing the thermal expansion coefficient of the glass and improve the melting property. Furthermore, B ２ O ３ is a component that can enhance the devitrification resistance stability. However, when the content of B ２ O ３ exceeds 35.10%, there is a risk that the water resistance will deteriorate. On the other hand, when the content of B ２ O ３ is 27.00% or less, there is a risk that the viscosity of the glass melt will increase and the effect of improving the melting property will not be sufficiently obtained. Therefore, in the glass of this embodiment, the content of B ２ O ３ is set in the range of more than 27.00% and 35.10% or less. From the same perspective, the content of B ２ O ３ in the glass of this embodiment is preferably 27.50% or more and preferably 35.05% or less.

[0027] <Al ２ O ３ > In the glass of this embodiment, Al ２ O ３ is a component that can lower the thermal expansion coefficient of the glass and improve the water resistance of the glass. Also, Al ２ O ３ is a component that can suppress the glass from phase-separating and enhance the devitrification resistance stability. However, when the content of Al ２ O ３ exceeds 12.00%, there is a risk that the melting property of the glass will deteriorate. On the other hand, when the content of Al ２ O ３ is less than 6.90%, there is a risk that the effect of lowering the thermal expansion coefficient of the glass and improving the water resistance of the glass cannot be sufficiently obtained. Also, when the content of Al ２ O ３ is less than 6.90%, there is a risk that the glass cannot be suppressed from phase-separating and the devitrification resistance stability will be significantly reduced. Therefore, in the glass of this embodiment, Al２ O ３ The content of was set in the range of 6.90% or more and 12.00% or less. From the same perspective, in the glass of this embodiment, Al ２ O ３ The content of is preferably 7.00% or more and preferably 11.80% or less.

[0028] <Li ２ O> In the glass of this embodiment, Li ２ O is a component that reduces the viscosity of the glass melt and improves the melting property the most among the alkali metal oxides. However, if the content of Li ２ O exceeds 8.00%, there is a risk that the thermal expansion coefficient of the glass will increase. On the other hand, if the content of Li ２ O is less than 0.90%, there is a risk that the effect of reducing the viscosity of the glass melt and improving the melting property cannot be sufficiently obtained. Therefore, in the glass of this embodiment, the content of Li ２ O was set in the range of 0.90% or more and 8.00% or less. From the same perspective, the content of Li ２ O in the glass of this embodiment is preferably 1.00% or more and preferably 7.80% or less.

[0029] <Na ２ O> In the glass of this embodiment, Na ２ O is not as effective as Li ２ O, but it is a component that reduces the viscosity of the glass melt and improves the melting property. However, if the content of Na ２ O exceeds 8.10%, there is a risk that the thermal expansion coefficient will increase and the water resistance will be significantly deteriorated. On the other hand, if the content of Na ２ O is less than 0.90%, there is a risk that the effect of reducing the viscosity of the glass melt and increasing the melting property cannot be sufficiently obtained. Therefore, in the glass of this embodiment, the content of Na<00001{08>O was set in the range of 0.90% or more and 8.10% or less. From the same perspective, the content of Na ２ O in the glass of this embodiment is preferably 1.00% or more and preferably 8.00% or less.

[0030] <K ２ O> In the glass of this embodiment, K２ O is Li ２ O, Na ２ Although not as much as O, it is a component that reduces the viscosity of the glass melt and improves its meltability. However, K ２ If the O content exceeds 5.10%, there is a risk that the coefficient of thermal expansion will increase. Therefore, in the glass of this embodiment, K ２ The O content was set to a range of 0% to 5.10%. From a similar viewpoint, the K in the glass of this embodiment ２ The O content is preferably 5.00% or less.

[0031] <R ２ O> R ２ O is Li ２ O, Na ２ O and K ２ This shows the sum of O. In the glass of this embodiment, R ２ The O content is 4.00% or more and less than 9.00%. ２ If the O content exceeds 9.00%, there is a risk that the thermal expansion coefficient of the glass will increase. On the other hand, R ２ If the O content is less than 4.00%, there is a risk that the effect of reducing the viscosity of the glass melt and improving its meltability will not be sufficiently obtained. From a similar viewpoint, the R in the glass of this embodiment ２ The O content is preferably 4.50% or more, and preferably 8.97% or less.

[0032] <MgO> In the glass of this embodiment, MgO is a component that can enhance the durability of the glass. However, if the MgO content exceeds 3.00%, the meltability of the glass may deteriorate. For this reason, in the glass of this embodiment, the MgO content is set to a range of 0% to 3.00%. From a similar viewpoint, it is preferable that the MgO content in the glass of this embodiment is 2.50% or less.

[0033] <CaO> In the glass of this embodiment, CaO is a component that can enhance the durability of the glass. However, if the CaO content exceeds 3.00%, the meltability of the glass may deteriorate. For this reason, in the glass of this embodiment, the CaO content is set to a range of 0% to 3.00%. From a similar viewpoint, it is preferable that the CaO content in the optical glass of this embodiment is 2.50% or less.

[0034] <SrO> In the optical glass of this embodiment, SrO is a component that can improve the devitrification resistance stability of the glass and also improve the durability of the glass. However, if the SrO content exceeds 4.00%, the meltability of the glass may deteriorate. For this reason, in the glass of this embodiment, the SrO content is set to a range of 0% to 4.00%. From a similar viewpoint, it is preferable that the SrO content in the optical glass of this embodiment is 3.50% or less.

[0035] <BaO> In the glass of this embodiment, BaO is a component that can improve the devitrification resistance stability of the glass and also improve the durability of the glass. However, if the BaO content exceeds 4.00%, the meltability of the glass may deteriorate. For this reason, in the glass of this embodiment, the BaO content is set to a range of 0% to 4.00%. From a similar viewpoint, it is preferable that the BaO content in the optical glass of this embodiment is 3.50% or less.

[0036] <R'O> R'O represents the sum of MgO, CaO, SrO, and BaO. In the glass of this embodiment, the R'O content is 0% or more and less than 5.00%. If the R'O content exceeds 5.00%, the meltability of the glass may deteriorate. Furthermore, in the optical glass of this embodiment, the R'O content is preferably 4.50% or less from the viewpoint of further improving the durability and devitrification resistance of the glass.

[0037] <Sb ２ O ３ > In the glass of this embodiment, Sb ２ O ３Sb is a component that can degas molten glass and can be added as desired. ２ O ３ The content of is 1.00% or less, and the effect of degassing the glass melt can be sufficiently obtained. Therefore, in the glass of this embodiment, Sb ２ O ３ The content was set to a range of 0% to 1.00%.

[0038] <F> In the glass of this embodiment, F is a clarification accelerator. By including a small amount of F (for example, more than 0.01%) in the glass, degassing occurs and clarification is promoted. On the other hand, if the F content exceeds 1.00%, harmful fluorine volatiles may be generated and remain in the glass as bubbles. Therefore, in the glass of this embodiment, the F content is set to a range of more than 0.01% and less than or equal to 1.00%. Here, F is KF, LiF, NaF, MgF as raw materials. ２ CaF ２ SrF ２ BaF ２ AlF ３ By using fluorides such as these, they can be incorporated into the glass.

[0039] <Cl> In the glass of this embodiment, Cl is a clarification accelerator. When 0.05% or more of Cl is added to the glass, small bubbles expand and rise to the surface, promoting clarification. However, if the Cl content exceeds 1.00%, there is a risk of reducing the ultraviolet light transmittance. Therefore, in the glass of this embodiment, the Cl content is set to a range of 0.05% to 1.00%. Here, Cl is used as a raw material, such as KCl, LiCl, NaCl, and AlCl ３ , MgCl ２ CaCl ２ , SrCl ２ BaCl ２ These chlorides can be incorporated into the glass by using them.

[0040] <(R ２ O+R'O) / (SiO ２ +B ２ O ３ +Al ２ O ３The mass ratio represented by ) > The glass of this embodiment is (R ２ O+R'O) / (SiO ２ +B ２ O ３ +Al ２ O ３ The mass ratio represented by (R) must be less than 0.1. Simply satisfying the above compositional requirements may not be sufficient to achieve both a low coefficient of thermal expansion and excellent water resistance. The glass of this embodiment contains a component (R) that increases the coefficient of thermal expansion. ２ The content of O and R'O, and components that lower the coefficient of thermal expansion or do not affect the coefficient of thermal expansion (SiO ２ , B ２ O ３ and Al ２ O ３ ) adjust the content, that is, (R ２ O+R'O) / (SiO ２ +B ２ O ３ +Al ２ O ３ By making the mass ratio represented by ) less than 0.1, the coefficient of thermal expansion can be reliably reduced. Therefore, the present invention satisfies the above composition requirements while (R ２ O+R'O) / (SiO ２ +B ２ O ３ +Al ２ O ３ By having a mass ratio less than 0.1, it is possible to provide UV-C transparent glass that has good meltability, a low coefficient of thermal expansion, and excellent water resistance.

[0041] <Fe ２ O ３ > Fe ２ O ３ It is a component that absorbs UV-C and may worsen UV-C transmittance. However, it is very difficult to completely avoid contamination from glass raw materials and manufacturing processes, and glass is usually made of Fe ２ O ３ It inevitably contains Fe. Therefore, the glass of this embodiment contains Fe ２ O ３It is preferable that the content of is low. Specifically, the glass of this embodiment is Fe ２ O ３ It is preferable that the content of is 0.01% or less, 0.005% or less, and 0.0005% or less. On the other hand, from the viewpoint of glass productivity, the glass of this embodiment is Fe ２ O ３ It is preferable that the content of is 0.00001% or more, or 0.0001% or more.

[0042] <TiO ２ > TiO ２ Fe ２ O ３ Similarly, it is a component that absorbs UV-C and may worsen UV-C transmittance. However, it is very difficult to completely avoid contamination from glass raw materials and manufacturing processes, and glass is usually TiO ２ It inevitably contains TiO. Therefore, the glass of this embodiment contains TiO ２ It is preferable that the content of is low. Specifically, the glass of this embodiment is TiO ２ It is preferable that the content of is 0.02% or less, 0.015% or less, and 0.01% or less. On the other hand, from the viewpoint of glass productivity, the glass of this embodiment is TiO ２ It is preferable that the content of is 0.0001% or more, and 0.0003% or more.

[0043] <Other Components> The glass of this embodiment contains the above-mentioned components (SiO) as long as it is used for the purpose. ２ , B ２ O ３ Al ２ O ３ Li ２ O, Na ２ O, K ２ O, MgO, CaO, SrO, BaO, Sb ２ O ３ F, Cl, Fe ２ O ３ , TiO ２ Other components may be included besides those mentioned above. Examples of other components include Gd ２ O, Y ２ O ３ La ２ O３ , ZrO ２ , GeO ２ Ta ２ O ５ , P ２ O ５ These are some examples. However, in the glass of this embodiment, from the viewpoint of more reliably exhibiting the desired properties, it is preferable that the content of the other components is 5% or less, more preferably 3% or less, and even more preferably 1% or less, and it is particularly preferable that the glass of this embodiment has a composition consisting only of the above-mentioned components. Here, "consisting only of the above-mentioned components" means that it substantially does not contain impurity components other than the above-mentioned components, specifically, it includes cases where the content of other components is 0.2% or less.

[0044] Cr ２ O ３ , NiO, CuO, CeO ２ , V ２ O ５ WO ３ MoO ３ MnO ２ , and CoO are components that may absorb UV-C and worsen UV-C transmittance. Therefore, it is preferable that the glass of this embodiment substantially does not contain these components.

[0045] Next, the various properties of the glass in this embodiment will be described.

[0046] <Fusibility> In this specification, "fusibility" refers to the phenomenon in which a vitrification reaction proceeds when homogeneously mixed raw materials are heated to a melting temperature, resulting in a completely molten state without any unmolten material remaining. The glass of this embodiment has good fusibility, resulting in a low melting temperature and less likelihood of unmolten material and / or bubbles remaining in the molten state. For example, the glass of this embodiment can be obtained by heating the raw materials of this embodiment in an electric furnace at a melting temperature of 1450°C for 3 hours, thereby obtaining a homogeneous glass free of unmolten material and / or bubbles.

[0047] <Thermal expansion coefficient> The thermal expansion coefficient is the mean linear expansion coefficient (α １００－３００℃This can be evaluated by measuring the mean linear expansion coefficient. The mean linear expansion coefficient is a physical property that indicates the rate at which the length of an object changes per unit temperature in response to an increase in temperature, and is also called the thermal expansion coefficient. Because the glass of this embodiment has a low thermal expansion coefficient, when heat is applied to a part of the glass and the temperature difference inside the glass becomes large, distortion is less likely to occur in the glass, and thermal cracking is less likely. From the viewpoint of further lowering the thermal expansion coefficient of the glass, the glass of this embodiment has a mean linear expansion coefficient (α １００－３００℃ ) is 60 x 10 －７ It is preferable that the temperature is below / ℃. From a similar viewpoint, the glass of this embodiment has an average coefficient of linear expansion (α １００－３００℃ ) is 59 x 10 －７ It is more preferable that the temperature is below / ℃. Furthermore, the glass of this embodiment has an average coefficient of linear thermal expansion (α １００－３００℃ ) is 45 x 10 －７ It is preferable that the temperature is above / ℃, and 46 × 10 －７ A temperature of / ℃ or higher is more preferable.

[0048] Note that the above-mentioned "average linear expansion coefficient (α) １００－３００℃ ) refers to the value measured in accordance with the Japan Optical Glass Manufacturers Association standard JOGIS08-2019 "Method for measuring the thermal expansion of optical glass". In addition, the "average linear expansion coefficient (α)" of the glass in this embodiment refers to the value measured in accordance with the Japan Optical Glass Manufacturers Association standard JOGIS08-2019 "Method for measuring the thermal expansion of optical glass". １００－３００℃ The adjustment of ) is, for example, by appropriately adjusting the content of each of the above-mentioned components within a predetermined range, (R ２ O+R'O) / (SiO ２ +B ２ O ３ +Al ２ O ３ This can be done by making the mass ratio expressed as ) less than 0.1.

[0049] <UV-C Transmittance> The glass of this embodiment has UV-C transmittance. UV-C transmittance can be evaluated by measuring the internal transmittance at a wavelength of 265 nm with a glass thickness of 1 mm. Specifically, the glass of this embodiment can have an internal transmittance of 90% or more at a wavelength of 265 nm with a glass thickness of 1 mm, and can also be 91% or more. The above-mentioned "internal transmittance" is determined in accordance with the calculation formula of JOGIS 17-2019 "Method for Measuring the Internal Transmittance of Optical Glass" of the Japan Optical Glass Manufacturers Association standard. Furthermore, the "internal transmittance" of the glass of this embodiment can be adjusted, for example, by appropriately adjusting the content of each of the above-mentioned components within a predetermined range.

[0050] <Glass Transition Temperature> The glass of this embodiment preferably has a glass transition temperature of 510°C or lower. The glass transition temperature is the temperature at which the material changes from a molten state to a glass, and it is also an indicator temperature for determining whether or not mold molding is possible. If the glass transition temperature is high, the molding temperature will also be high, which may cause problems such as the glass adhering to the mold used and being unable to be released. For this reason, it is preferable that the glass transition temperature be as low as possible, and in the glass of this embodiment, it is more preferable that the glass transition temperature be 500°C or lower, and even more preferable that it be 490°C or lower.

[0051] The "glass transition point" mentioned above refers to the temperature corresponding to the intersection of two tangent lines drawn from the low-temperature and high-temperature sides of the bend in the thermal expansion curve measured in accordance with the Japan Optical Glass Manufacturers Association standard JOGIS 08-2019 "Method for Measuring Thermal Expansion of Optical Glass". Furthermore, the "glass transition point" of the glass in this embodiment can be adjusted, for example, by appropriately adjusting the content of each component mentioned above within a predetermined range.

[0052] <Water Resistance> Water resistance can be evaluated by calculating the weight loss rate. In this specification, "weight loss rate" for glass refers to the weight loss rate (mass %) of a glass piece measuring 20 mm x 10 mm x 10 mm when the glass piece is boiled in 1000 ml of pure water for 60 minutes. The weight loss rate is calculated using the following formula: Weight loss rate = ("Mass of glass piece before boiling" - "Mass of glass piece after boiling") x 100 / "Mass of glass piece before boiling"

[0053] The glass of this embodiment has excellent water resistance, and for example, it is preferable that the weight loss rate is less than 0.1% by mass.

[0054] The "weight loss rate" of the glass in this embodiment can be adjusted, for example, by appropriately adjusting the content of each of the above-mentioned components within a predetermined range.

[0055] (Method for Manufacturing UV-C Transmitting Glass) Next, the method for manufacturing the glass of this embodiment will be described. Here, the glass of this embodiment only needs to satisfy the above-mentioned range in the composition (content, mass ratio) of each component, and the manufacturing method is not particularly limited and can be manufactured according to conventional manufacturing methods. For example, first, oxides, hydroxides, carbonates, nitrates, fluorides, chlorides, etc., are weighed in predetermined proportions as raw materials for each component that may be contained in the optical glass of this embodiment, and the mixture is thoroughly mixed to form the glass compounding raw material. Next, this glass compounding raw material is placed in a melting vessel that does not react with the glass compounding raw material, etc. (for example, a crucible of platinum group metals, platinum group metal alloys, quartz, etc.), heated in an electric furnace to 1300 to 1450°C to melt, and stirred as needed. Then, after clarifying and homogenizing in the electric furnace, it is cast into a mold preheated to an appropriate temperature, and then slowly cooled in the electric furnace to remove distortion, thereby manufacturing the glass of this embodiment.

[0056] (Applications of UV-C Transmitting Glass) The glass of this embodiment is not particularly limited in its applications, but it is preferably used for precision mold press molding. Since the glass of this embodiment also has advantages in mold molding, by using the glass of this embodiment in precision mold press molding, the glass parts described later can be easily manufactured.

[0057] (Glass parts) The following describes the glass parts of one embodiment of the present invention (hereinafter sometimes referred to as "glass parts of this embodiment"). The glass parts of this embodiment are characterized by using the above-mentioned UV-C transparent glass as the material. Because the glass parts of this embodiment use the above-mentioned UV-C transparent glass as the material, they have a low coefficient of thermal expansion and excellent water resistance.

[0058] The glass components of this embodiment are not particularly limited, but examples include LED cover lenses, lens arrays such as microlens arrays, prisms with lens functions, preform materials, fiber materials, etc. If the glass component includes a lens, the lens may be a spherical lens, aspherical lens, plano-concave lens, plano-convex lens, biconcave lens, biconvex lens, concave meniscus lens, convex meniscus lens, microlens, lens with diffraction grating, rod lens, etc. Furthermore, the lens may be provided with an anti-reflective coating, a wavelength-selective partial reflective coating, etc., on its surface as needed.

[0059] The method for manufacturing the glass component of this embodiment is not particularly limited, and a known method can be appropriately selected depending on the purpose. For example, the glass of this embodiment can be precision molded using a press molding method.

[0060] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0061] The glass used in the examples and comparative examples was manufactured by the following method.

[0062] For each component in the compositions listed in Tables 1 to 8, the corresponding oxides, hydroxides, carbonates, nitrates, fluorides, chlorides, etc., were used as raw materials, weighed to the desired proportions, and thoroughly mixed to form the raw materials for the blend. Next, the raw materials were placed in a platinum crucible and melted in an electric furnace at a temperature of 1300 to 1450°C for several hours, while being stirred periodically with a platinum stirring rod to homogenize and clarify the mixture. After that, the mixture was cast into a mold that had been preheated to an appropriate temperature, and then slowly cooled in an electric furnace to obtain the glass for each example. In each example, AlF was used as the fluoride. ３ The following was used, and NaCl was used as the chloride. Also, the glass in each example was Fe ２ O ３ The content of is 0.01% by mass or less, and TiO ２ The content was 0.02% by mass or less.

[0063] Comparative Examples 1 and 2 correspond to the compositions of Examples 1 and 4 described in Patent Document 1 (Japanese Unexamined Patent Publication No. 4-342437), respectively, while Comparative Example 3 corresponds to Example 1 of Patent Document 2 (Japanese Unexamined Patent Publication No. 2018-197190). Comparative Examples 4, 5, and 6 correspond to Documents No. 1, 8, and 11 of Patent Document 3 (Japanese Unexamined Patent Publication No. 2012-140314). Furthermore, Comparative Example 7 corresponds to Example 1 of Patent Document 4 (Japanese Unexamined Patent Publication No. 2013-230952).

[0064] For each example of glass obtained, the fusion properties, thermal expansion coefficient, water resistance, and UV-C transmittance were evaluated, and the glass transition temperature was measured according to the following procedure. The results are shown in Tables 1 to 7.

[0065] <Evaluation of Meltability> For evaluation of meltability, the blended raw materials were heated in an electric furnace at a temperature of 1450°C for 3 hours. If no unmelted material or bubbles were observed, the result was rated "A," and if unmelted material or bubbles were observed, the result was rated "B."

[0066] <Evaluation of Thermal Expansion Coefficient> As an evaluation of thermal expansion coefficient, the mean linear expansion coefficient (α) １００－３００℃ ) was measured. Specifically, the mean coefficient of linear expansion (α １００－３００℃The measurement of the average linear expansion coefficient (α) was performed according to the method described in JOGIS 08-2019 "Method for measuring thermal expansion of optical glass" of the Japan Optical Glass Manufacturers Association standard. １００－３００℃ A smaller value of ) indicates a lower (better) coefficient of thermal expansion.

[0067] <Evaluation of Water Resistance> To evaluate water resistance, the weight loss rate was calculated. Specifically, the weight loss rate was calculated using the following method. For each example, a glass piece measuring 20 mm x 10 mm x 10 mm was used, and this glass piece was boiled in 1000 ml of pure water for 60 minutes. After that, the weight loss rate was calculated using the following formula. A smaller weight loss rate indicates better water resistance. Weight loss rate = ("Mass of glass piece before boiling" - "Mass of glass piece after boiling") x 100 / "Mass of glass piece before boiling"

[0068] <Measurement of Glass Transition Temperature> The glass transition temperature was measured according to the method described in JOGIS 08-2019, "Method for Measuring Thermal Expansion of Optical Glass," a standard of the Japan Optical Glass Manufacturers Association. A lower glass transition temperature indicates better moldability.

[0069] <Evaluation of UV-C Transmittance> To evaluate UV-C transmittance, the internal transmittance at a wavelength of 265 nm was measured at a glass thickness of 1 mm. Specifically, the calculation of the internal transmittance at a wavelength of 265 nm at a glass thickness of 1 mm was performed according to the method described in the Japan Optical Glass Manufacturers Association standard JOGIS 17-2019 "Method for Measuring the Internal Transmittance of Optical Glass". A higher value of this internal transmittance indicates better UV-C transmittance.

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076]

[0077]

[0078] From Tables 1 to 3, the glasses of Examples 1 to 20 according to the present invention have a meltability evaluation result of "A" and an average linear thermal expansion coefficient (α １００-３００℃ ) is 60 x 10 －７ The temperature was below / °C, the weight loss rate was less than 0.10% by mass, and the internal transmittance at a wavelength of 265 nm with a glass thickness of 1 mm was 90% or more. From these results, it can be seen that the glasses of Examples 1 to 20 have good meltability, low coefficient of thermal expansion, excellent water resistance, and excellent UV-C transmittance.

[0079] Furthermore, the glass of Examples 1 to 20 had a glass transition temperature of 510°C or lower. This indicates that the glass of Examples 1 to 20 also has advantages in mold molding.

[0080] On the other hand, as shown in Tables 4 to 8, the glasses of Comparative Examples 1 to 33 do not satisfy any of the ranges defined in the present invention, and therefore are glasses with poor meltability, high thermal expansion coefficient, and / or poor water resistance.

[0081] The glass in Comparative Example 1 received a "B" rating for its fusion properties. This is because SiO ２ The high content of B ２ O ３ This is thought to be due to the low content of [the substance].

[0082] The glass in Comparative Example 2 received a "B" rating for its fusion properties. ２ O ３ This is thought to be due to the low content of [the substance].

[0083] Furthermore, the glass of Comparative Examples 1 and 2 had a low internal transmittance [%] at a wavelength of 265 nm at a glass thickness of 1 mm. This is thought to be due to the poor meltability of the glass of Comparative Examples 1 and 2, resulting in the retention of unmelted material and bubbles within the glass.

[0084] The glass in Comparative Example 3 had a meltability evaluation result of "B", and the average coefficient of linear thermal expansion (α) １００-３００℃ The glass of Comparative Example 3 had a high glass transition temperature. These are due to SiO ２ and Na２ The high content of O, (R ２ O+R'O) / (SiO ２ +B ２ O ３ +Al ２ O ３ This is thought to be due to the fact that the mass ratio expressed as ) is 0.1 or greater.

[0085] The glass of Comparative Example 4 has an average coefficient of linear expansion (α １００-３００℃ ) was high. This is because (R ２ O+R'O) / (SiO ２ +B ２ O ３ +Al ２ O ３ This is thought to be due to the fact that the mass ratio expressed as ) is 0.1 or greater.

[0086] The glass of Comparative Example 5 had a meltability evaluation result of "B", and the average linear expansion coefficient (α) １００-３００℃ The glass of Comparative Example 5 had a high glass transition temperature. These are due to SiO ２ The high content of (R ２ O+R'O) / (SiO ２ +B ２ O ３ +Al ２ O ３ This is thought to be due to the fact that the mass ratio expressed as ) is 0.1 or greater.

[0087] The glasses of Comparative Examples 6 and 7 have an average coefficient of linear thermal expansion (α １００-３００℃ ) was high. This is because (R ２ O+R'O) / (SiO ２ +B ２ O ３ +Al ２ O ３ This is thought to be due to the fact that the mass ratio expressed as ) is 0.1 or greater.

[0088] The glass in Comparative Examples 8 to 25 is (R ２ O+R'O) / (SiO ２ +B ２ O ３ +Al ２ O ３The glass has a mass ratio expressed as ) which is less than 0.1, but the content of any of the components in the glass does not meet the range of each component in the composition requirements.

[0089] The glass in Comparative Example 8 showed a large weight loss rate. This is because SiO ２ The low content of B ２ O ３ This is thought to be due to the high content of [the substance].

[0090] The glass of Comparative Example 9 showed a particularly large weight loss rate. Furthermore, the glass of Comparative Example 9 underwent phase separation, and the internal transmittance [%] at a wavelength of 265 nm with a glass thickness of 1 mm was almost 0. These were due to Al ２ O ３ This is thought to be due to the content being too low.

[0091] The glass in Comparative Example 10 showed a large weight loss rate. This is because Al ２ O ３ This is thought to be due to the low content of [the substance].

[0092] The glass in Comparative Examples 11-13 received a "B" rating for fusion properties. This is because Al ２ O ３ This is thought to be due to the high content of [the substance].

[0093] The glass of Comparative Example 14 received a meltability evaluation result of "B". This is because the glass of Comparative Example 14 contains Li ２ This is thought to be due to the absence of oxygen (O).

[0094] The glass of Comparative Example 15 received a meltability evaluation result of "B". This is because the glass of Comparative Example 15 contains Li ２ It does not contain O, Na ２ This is thought to be due to the low oxygen content. Furthermore, the glass of Comparative Example 15 had a low internal transmittance [%] at a wavelength of 265 nm at a glass thickness of 1 mm. This is thought to be due to the poor meltability of the glass of Comparative Example 15, resulting in the retention of unmelted material and bubbles within the glass.

[0095] The glass of Comparative Example 16 has an average coefficient of linear thermal expansion (α １００-３００℃ ) was high. This is because K ２This is thought to be due to the high content of oxygen (O).

[0096] The glass in Comparative Example 17 received a "B" rating for its fusion properties. This is because R ２ This is thought to be due to the low oxygen content.

[0097] The glass of Comparative Examples 18 and 19 has an average coefficient of linear thermal expansion (α １００-３００℃ ) was high. This is because Li ２ High O content, Na ２ This is thought to be due to the low oxygen content.

[0098] The glass of Comparative Example 20 has an average coefficient of linear thermal expansion (α １００-３００℃ ) was high. These are Li ２ Low O content, Na ２ This is thought to be due to the high content of oxygen (O).

[0099] The glass of Comparative Example 21 has an average coefficient of linear expansion (α １００-３００℃ ) was high and the weight loss rate was large. These were Li ２ It does not contain O, Na ２ This is thought to be due to the high content of oxygen (O).

[0100] The glass in Comparative Example 22 received a "B" rating for its fusion properties. This is thought to be due to its high MgO content.

[0101] The glass in Comparative Example 23 received a "B" rating for its fusion properties. This is thought to be due to its high CaO content.

[0102] The glass in Comparative Example 24 received a "B" rating for its fusion properties. This is thought to be due to its high SrO content.

[0103] The glass in Comparative Example 25 received a "B" rating for its fusion properties. This is thought to be due to its high BaO content.

[0104] The glass of Comparative Example 26 has an average coefficient of linear expansion (α １００-３００℃ ) was high, and the weight loss rate was large. This is because R ２ It has a high O content, (R ２O+R'O) / (SiO ２ +B ２ O ３ +Al ２ O ３ This is thought to be due to the fact that the mass ratio expressed as ) is 0.1 or greater.

[0105] The glass of Comparative Example 32 has an average coefficient of linear expansion (α １００-３００℃ ) was high. This is because R ２ It has a high O content, (R ２ O+R'O) / (SiO ２ +B ２ O ３ +Al ２ O ３ This is thought to be due to the fact that the mass ratio expressed as ) is 0.1 or greater.

[0106] Comparative Examples 27-31 and 33 satisfy the composition requirements, but (R ２ O+R'O) / (SiO ２ +B ２ O ３ +Al ２ O ３ The glass has a mass ratio of 0.1 or greater, expressed as α. The glasses of Comparative Examples 27 to 31 all have an average coefficient of linear expansion (α). １００-３００℃ ) was high. Also, the glass of Comparative Example 33 had a large weight loss rate. From these facts, even if the composition requirements are met, (R ２ O+R'O) / (SiO ２ +B ２ O ３ +Al ２ O ３ It can be seen that if the mass ratio expressed as ) is 0.1 or higher, it is not possible to achieve both a low coefficient of thermal expansion and excellent water resistance.

[0107] According to the present invention, it is possible to provide UV-C transparent glass with good meltability, low thermal expansion coefficient, and excellent water resistance in a specific composition of aluminoborosilicate glass. Furthermore, according to the present invention, it is possible to provide glass components using the above-mentioned UV-C transparent glass.

Claims

1. By mass percentage, SiO ２ : 46.90% or more and less than 55.00%, B ２ O ３ : more than 27.00% and 35.10% or less, Al ２ O ３ : 6.90% or more and 12.00% or less, Li ２ O: 0.90% or more and 8.00% or less, Na ２ O: 0.90% or more and 8.10% or less, K ２ O: 0% or more and 5.10% or less, R ２ O: 4.00% or more and less than 9.00% (however, R ２ O is the sum of Li ２ O, Na ２ O and K ２ O).), MgO: 0% or more and 3.00% or less, CaO: 0% or more and 3.00% or less, SrO: 0% or more and 4.00% or less, BaO: 0% or more and 4.00% or less, R'O: 0% or more and less than 5.00% (however, R'O is the sum of MgO, CaO, SrO and BaO.), Sb ２ O ３ : 0% or more and 1.00% or less, F: more than 0.01% and 1.00% or less, Cl: 0.05% or more and 1.00% or less, and the mass ratio represented by (R ２ O + R'O) / (SiO ２ + B ２ O ３ + Al ２ O ３ )) is less than 0.1, characterized by a UV-C transmitting glass.

2. Average coefficient of linear expansion (α １００－３００℃ ) is 45 x 10 －７ / ℃ or higher 60 x 10 －７ The UV-C transmitting glass according to claim 1, wherein the temperature is below / ℃.

3. The UV-C transmitting glass according to claim 1 or 2, wherein the internal transmittance at a wavelength of 265 nm at a glass thickness of 1 mm is 90% or more.

4. The UV-C transparent glass according to claim 1 or 2, wherein the glass transition temperature is 510°C or lower.

5. The UV-C transparent glass according to claim 1 or 2, wherein the glass piece is 20 mm x 10 mm x 10 mm, and when the glass piece is boiled in 1000 ml of pure water for 60 minutes, the weight loss before and after the boiling treatment is less than 0.1% by mass.

6. The UV-C transparent glass according to claim 1 or 2, for use in precision mold press molding.

7. A glass component characterized by using the UV-C transparent glass described in claim 1 or 2 as a material.

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