UV through visible light absorbing glass and UV through visible light absorbing filter

Abstract

The present invention provides an ultraviolet-transmitting visible light absorbing glass, which selectively improves the transmittance of irradiated light in the wavelength range of 350 to 370 nm while reducing environmental load, thereby suppressing degradation caused by overexposure. The ultraviolet-transmitting visible light absorbing glass is characterized in that it substantially does not contain Pb, As, Cd and Cr, but contains 0.1 to 2 mass % of CoO, 1 to 5 mass % of NiO, and 1 to 2 mass % of TiO. 2 0-1 mass%, Nb 2 O 5 0.1 to 10% by mass, and the TiO 2 and Nb 2 O 5 The total content ratio is 0.1 to 10% by mass.

Description

[0001] This application is a divisional application of the parent application with application number 201610860683.7 and application date September 28, 2016. Technical Field

[0002] The invention relates to an ultraviolet-transmitting visible-light absorbing glass and an ultraviolet-transmitting visible-light absorbing filter. Background Art

[0003] Currently, in ultraviolet irradiation devices such as light sources for ultraviolet curing resins, ultraviolet-transmitting visible light absorption filters that absorb visible light while selectively transmitting ultraviolet light are used. As black glass constituting such filters, for example, silicate glass described in Patent Document 1 (Japanese Patent Publication No. 4-32019) has been proposed.

[0004] Patent Document 1: Japanese Patent Publication No. 4-32019 Summary of the invention

[0005] However, the black glass described in Patent Document 1 contains PbO or As2O3 in order to improve the ultraviolet transmittance or adjust the transmittance. In contrast, in recent years, in order to reduce the environmental load, glass that does not contain elements such as Cd and Cr in addition to Pb and As is sought.

[0006] On the other hand, in order to save energy and improve work efficiency, the ultraviolet-transmitting visible light absorbing glass used in the above-mentioned optical filter is required to have excellent visible light absorptivity and ultraviolet light transmittance even if it does not contain the above-mentioned elements.

[0007] In addition, if optical glass is irradiated with light of high radiant illuminance at high brightness, a coloring phenomenon called solarization will occur, which will easily cause a decrease in the light transmittance of the glass. This overexposure is particularly likely to occur when irradiated with light including light in the ultraviolet range. Therefore, even glass used for ultraviolet transmission and visible light absorption filters will deteriorate (absorption in the ultraviolet range) when used for a long time, which will easily cause a decrease in the light transmittance in the ultraviolet range.

[0008] Under such circumstances, the object of the present invention is to provide a new type of ultraviolet-transmitting visible light absorbing glass and an ultraviolet-transmitting visible light absorbing filter composed of the glass, which can selectively increase the transmittance of irradiated light in the wavelength range of 350 to 370 nm while reducing the environmental load, thereby suppressing degradation caused by overexposure.

[0009] In order to achieve the above-mentioned purpose, the present inventors have conducted intensive studies and found that the above-mentioned technical problems can be solved by using an ultraviolet-transmitting visible light absorbing glass which does not substantially contain Pb, As, Cd and Cr, but contains 0.1 to 2 mass % of CoO, 1 to 5 mass % of NiO, 0 to 1 mass % of TiO2, and 0.1 to 10 mass % of Nb2O5, with the total content of TiO2 and Nb2O5 being 0.1 to 10 mass %. The present invention was completed based on this finding.

[0010] That is, the present invention provides:

[0011] (1) An ultraviolet-transmitting visible-light-absorbing glass, which contains substantially no Pb, As, Cd, and Cr, but contains 0.1 to 2 mass % of CoO, 1 to 5 mass % of NiO, 0 to 1 mass % of TiO2, and 0.1 to 10 mass % of Nb2O5, wherein the total content of the TiO2 and Nb2O5 is 0.1 to 10 mass %,

[0012] (2) The ultraviolet-transmitting visible light absorbing glass described in (1) above, wherein the content ratio of TiO2 relative to the total content ratio of TiO2 and Nb2O5 (TiO2 / (TiO2+Nb2O5)) is 0 to 0.5,

[0013] (3) The ultraviolet-transmitting visible light absorbing glass described in (1) or (2) above further comprises:

[0014]

[0015] (4) The ultraviolet-transmitting visible light absorbing glass described in any one of (1) to (3) above, in the form of a plate with a thickness of 3 mm, is irradiated with a power of 500 mW·cm from a light source having a maximum radiation intensity at a wavelength of 365 nm. -2 When the irradiation light including ultraviolet light and visible light is irradiated with a radiation intensity of 1000 nm, the maximum value of the light transmittance in the wavelength range of 350 to 370 nm at the start of irradiation of the irradiation light is 75% or more,

[0016] (5) The ultraviolet-transmitting visible light absorbing glass described in (4) above, in the form of a plate with a thickness of 3 mm, is irradiated with a light source having a maximum radiation intensity at a wavelength of 365 nm at a power of 500 mW / cm -2 When irradiated with irradiation light including ultraviolet light and visible light with a radiation intensity of 1000 nm, the transmittance in the wavelength range of 200 to 290 nm and the transmittance in the wavelength range of 410 to 690 nm at the start of irradiation of the irradiation light are both less than 1%,

[0017] (6) The ultraviolet-transmitting visible light absorbing glass described in any one of (1) to (5) above, in the form of a plate having a thickness of 3 mm, is irradiated with a power of 500 mW / cm2 from a light source having a maximum radiation intensity at a wavelength of 365 nm. -2 When the irradiation light including ultraviolet light and visible light is irradiated for 100 hours, the maintenance rate represented by the following formula (I) is 90% or more, (B / A)×100(I)

[0018] Wherein, A is the maximum value (%) of the transmittance in the wavelength range of 350 to 370 nm at the start of the irradiation of the irradiation light, B is the maximum value (%) of the transmittance in the wavelength range of 350 to 370 nm at the moment when 100 hours have passed since the start of the irradiation of the irradiation light,

[0019] (7) An ultraviolet-transmitting visible-light-absorbing filter, comprising the ultraviolet-transmitting visible-light-absorbing glass as described in any one of (1) to (6) above.

[0020] Effects of the invention:

[0021] According to the present invention, there can be provided an ultraviolet-transmitting visible light absorbing glass which selectively improves the transmittance of irradiated light in the wavelength range of 350 to 370 nm while reducing environmental load, thereby suppressing degradation caused by overexposure, and an ultraviolet-transmitting visible light absorbing filter composed of the glass can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a diagram showing the transmission spectrum of ultraviolet rays through the visible light absorbing glass obtained in Example 1 of the present application.

[0023] Figure 2 This is a diagram showing the transmission spectrum of ultraviolet rays passing through the visible light absorbing glass obtained in Example 2 of the present application.

[0024] Figure 3 This is a diagram showing the transmission spectrum of ultraviolet rays passing through the visible light absorbing glass obtained in Example 5 of the present application.

[0025] Figure 4 This is a diagram showing the transmission spectrum of ultraviolet rays through the visible light absorbing glass obtained in Comparative Example 1 of the present application.

[0026] Figure 5 This is a diagram showing the transmission spectrum of ultraviolet rays through the visible light absorbing glass obtained in Comparative Example 2 of the present application. DETAILED DESCRIPTION

[0027] First, the ultraviolet-transmitting visible light absorbing glass according to the present invention will be described.

[0028] The ultraviolet-transmitting visible-light-absorbing glass of the present invention is characterized in that it contains substantially no Pb, As, Cd and Cr, but contains 0.1 to 2 mass % of CoO, 1 to 5 mass % of NiO, 0 to 1 mass % of TiO2, and 0.1 to 10 mass % of Nb2O5, and the total content of the TiO2 and Nb2O5 is 0.1 to 10 mass %.

[0029] In this application document, the ultraviolet-transmitting visible light absorbing glass refers to glass that selectively transmits ultraviolet light in the wavelength range of 350 to 370 nm and selectively absorbs visible light in the wavelength range of 410 to 690 nm when irradiated with light containing ultraviolet light and visible light.

[0030] The ultraviolet-transmitting visible-light-absorbing glass according to the present invention contains 0.1 to 2 mass % of CoO, more preferably 0.1 to 1 mass % of CoO.

[0031] CoO is an essential component of the ultraviolet-transmitting visible light absorbing glass according to the present invention, and is a component that transmits ultraviolet light and absorbs visible light.

[0032] When the content of CoO is less than 0.1 mass %, it is difficult to fully exert the above-mentioned effect, and when the content of CoO exceeds 2 mass %, the light transmittance in the ultraviolet range tends to decrease.

[0033] Furthermore, the ultraviolet-transmitting visible light absorbing glass according to the present invention contains 1 to 5% by mass of NiO, more preferably 1 to 3% by mass of NiO.

[0034] NiO is an essential component of the ultraviolet-transmitting visible light absorbing glass according to the present invention, and is a component that transmits ultraviolet light and absorbs visible light.

[0035] When the content of NiO is less than 1 mass %, it is difficult to fully exert the above-mentioned effect, and when the content of NiO exceeds 5 mass %, the light transmittance in the ultraviolet range tends to decrease.

[0036] The total content of CoO and NiO is preferably 1.1 to 7% by mass, and the total content of CoO and NiO is more preferably 1.1 to 4% by mass.

[0037] The ultraviolet-transmitting visible light absorbing glass according to the present invention contains both CoO and NiO, thereby being able to transmit ultraviolet rays and effectively absorb light in the entire visible light range of 410 nm to 690 nm in wavelength.

[0038] If the total content of CoO and NiO is less than 1.1 mass %, it is difficult to sufficiently absorb visible light, and if the total content of CoO and NiO exceeds 7 mass %, the light transmittance in the ultraviolet range tends to decrease.

[0039] The ultraviolet-transmitting visible-light-absorbing glass according to the present invention contains 0 to 1% by mass of TiO2, and more preferably contains 0 to 0.5% by mass of TiO2.

[0040] TiO2 is an optional component of the ultraviolet-transmitting visible light absorbing glass of the present invention, and can interact with Nb2O5 described later to exert the desired ultraviolet-transmitting effect and the effect of suppressing degradation caused by overexposure.

[0041] However, if the content of TiO2 increases, the light transmittance in the ultraviolet range tends to decrease, so the content is limited to 1 mass % or less.

[0042] The ultraviolet-transmitting visible light absorbing glass according to the present invention contains 0.1 to 10% by mass of Nb2O5, preferably 0.1 to 5% by mass of Nb2O5, and more preferably 0.5 to 5% by mass of Nb2O5.

[0043] In the ultraviolet-transmitting visible light absorbing glass involved in the present invention, Nb2O5 is a necessary component. According to the research of the present inventors, it is found that in a glass system that does not substantially contain Pb, As, Cd and Cr, but contains a specified amount of CoO, NiO and TiO2, by containing a specified amount of Nb2O5, appropriate light absorption can be performed in the visible light range, and high light transmittance can be exerted in the ultraviolet range, which can further suppress the deterioration caused by excessive exposure, until the present invention was completed.

[0044] In the ultraviolet-transmitting visible light absorbing glass involved in the present invention, when the Nb2O5 content is less than 0.1 mass %, degradation caused by overexposure is likely to occur, and if the Nb2O5 content exceeds 10 mass %, the transmittance in the ultraviolet range is likely to decrease.

[0045] In the ultraviolet-transmitting visible light absorbing glass of the present invention, the total content ratio of TiO2 and Nb2O5 (TiO2+Nb2O5) is 0.1~10 mass%, and the total content ratio of TiO2 and Nb2O5 (TiO2+Nb2O5) is more preferably 0.1~5 mass%.

[0046] In the ultraviolet-transmitting visible light absorbing glass involved in the present invention, when the combined content ratio of TiO2 and Nb2O5 (TiO2+Nb2O5) is less than 0.1 mass %, degradation caused by overexposure is likely to occur, and when it exceeds 10 mass %, the transmittance in the ultraviolet range is likely to decrease.

[0047] Furthermore, in the ultraviolet-transmitting visible light absorbing glass according to the present invention, the content ratio of TiO2 relative to the total content ratio of TiO2 and Nb2O5 (TiO2 / (TiO2+Nb2O5)) is preferably 0 to 0.5.

[0048] In the ultraviolet-transmitting visible-light-absorbing optical glass of the present invention, when the TiO2 content ratio (TiO2 / (TiO2+Nb2O5)) relative to the total content (mass %) of TiO2 and Nb2O5 exceeds 0.5, the transmittance in the ultraviolet light range is easily reduced.

[0049] The ultraviolet-transmitting visible-light-absorbing optical glass of the present invention substantially does not contain Pb, As, Cd and Cr.

[0050] In the present application document, the phrase “substantially free of Pb, As, Cd or Cr” means that no Pb, As, Cd or Cr compound is used as a raw material, but does not exclude the possibility that the compound is unintentionally mixed as an impurity.

[0051] The ultraviolet-transmitting visible-light-absorbing optical glass according to the present invention preferably contains 50 to 70% by mass of SiO2.

[0052] SiO2 is a network-forming oxide of glass and is an important component for exerting thermal stability and chemical durability.

[0053] When the content of SiO2 is less than 50% by mass, it is difficult to exhibit the desired thermal stability and chemical durability, while when it exceeds 70% by mass, it is difficult to melt and the moldability is likely to decrease.

[0054] The ultraviolet-transmitting and visible-light-absorbing optical glass according to the present invention preferably contains 0 to 5% by mass of B2O3.

[0055] B2O3 is also a cross-linking oxide of glass and is an effective component for improving the solubility and thermal stability of glass. However, if its content exceeds 5% by mass, the chemical durability is likely to decrease.

[0056] The ultraviolet-transmitting visible-light-absorbing optical glass according to the present invention preferably contains 0 to 5% by mass of Al2O3.

[0057] Al2O3 is also a cross-linking oxide of glass and is an effective component for suppressing phase separation or devitrification of glass. However, if its content exceeds 5% by mass, the viscosity of the glass increases, making it difficult to melt and shape.

[0058] In the ultraviolet-transmitting visible-light-absorbing optical glass according to the present invention, the total content ratio of SiO2, B2O3 and Al2O3 (SiO2+B2O3+Al2O3) is preferably 50 to 70% by mass.

[0059] By setting the total content of SiO 2 , B 2 O 3 and Al 2 O 3 to be within the above range, thermal stability and chemical durability can be easily exhibited.

[0060] The ultraviolet-transmitting visible-light-absorbing optical glass according to the present invention preferably contains 5 to 20% by mass of Na2O, and more preferably contains 5 to 15% by mass of Na2O.

[0061] Na2O is a component that lowers the melting temperature of glass and improves its solubility. However, when the content is less than 5% by mass, the viscosity of the glass increases and it becomes difficult to melt. When the content exceeds 20% by mass, the chemical durability tends to decrease.

[0062] The ultraviolet-transmitting visible light absorbing optical glass of the present invention can obtain the following effects when a part of Na2O is replaced by K2O, so K2O is preferred. That is, by increasing the viscosity of the glass when it is melted, the corrosion of the melting tank (refractory, etc.) is suppressed, thereby suppressing the mixing of impurities from the melting tank material (refractory, etc.) into the molten glass, and as a result, the transmittance of the irradiated light in the wavelength range of 350 to 370nm can be prevented from decreasing. In addition, there are also effects such as increasing the softening point of the glass and improving the heat resistance of the glass, and improving the chemical durability of the glass. However, if the replacement amount of K2O is too large, the viscosity of the molten glass will be too high, making it difficult to melt, and the problem of decreased resistance to devitrification will occur, so the replacement amount must be within a certain range.

[0063] As described above, in the ultraviolet-transmitting visible light absorbing optical glass of the present invention, the total content ratio of Na2O and K2O (Na2O+K2O) is 5 to 20 mass %, preferably, K2O contains 0 to 10 mass %, and more preferably, K2O contains 2 to 8 mass %.

[0064] The ultraviolet-transmitting visible-light-absorbing optical glass according to the present invention preferably contains 0 to 15% by mass of CaO.

[0065] CaO is a component that stabilizes glass, and is a component that is effective in improving the chemical durability, melt moldability, and devitrification resistance of glass.

[0066] When the content of CaO exceeds 15 mass %, it is difficult to obtain sufficient devitrification resistance.

[0067] The ultraviolet-transmitting visible-light absorbing glass according to the present invention preferably contains 0 to 5 mass % of ZnO.

[0068] ZnO is also a component that stabilizes glass and is effective in improving the chemical durability of glass.

[0069] When the content ratio of ZnO exceeds 5 mass %, the devitrification resistance tends to decrease.

[0070] The ultraviolet-transmitting visible-light-absorbing optical glass according to the present invention preferably contains 0 to 15 mass % of BaO.

[0071] BaO is also a component that stabilizes glass and is effective in improving the chemical durability of glass.

[0072] When the content of BaO exceeds 15 mass %, it is difficult to obtain sufficient devitrification resistance.

[0073] In the ultraviolet-transmitting visible light absorbing glass according to the present invention, the total content of CaO, ZnO and BaO (CaO+ZnO+BaO) is preferably 0 to 30% by mass, and the total content of CaO, ZnO and BaO (CaO+ZnO+BaO) is more preferably 5 to 20% by mass.

[0074] In the ultraviolet-transmitting visible light absorbing glass according to the present invention, by making the total content ratio of CaO, ZnO, and BaO within the above range, the chemical durability and devitrification resistance of the glass can be easily improved.

[0075] The ultraviolet-transmitting visible light absorbing glass according to the present invention preferably contains 0 to 2% by mass of Sb2O3, and more preferably contains 0 to 1% by mass of Sb2O3.

[0076] Sb2O3 is a useful component as a clarifier (defoaming agent), but if its content exceeds 2% by mass, the clarification is likely to decrease.

[0077] As the ultraviolet-transmitting visible light absorbing glass according to the present invention,

[0078] It contains essentially no Pb, As, Cd and Cr, but contains:

[0079]

[0080] The total amount of TiO2 and Nb2O5 is 0.1-10% by mass.

[0081] The content ratio of TiO2 (TiO2 / (TiO2+Nb2O5)) is preferably 0 to 0.5 relative to the total content ratio of TiO2 and Nb2O5.

[0082] In addition, as the ultraviolet-transmitting visible light absorbing glass according to the present invention,

[0083] It contains essentially no Pb, As, Cd and Cr, but contains:

[0084]

[0085] The total amount of TiO2 and Nb2O5 is 0.1 to 10% by mass, and preferably includes:

[0086]

[0087] In addition, as the ultraviolet-transmitting visible light absorbing glass according to the present invention,

[0088] It contains essentially no Pb, As, Cd and Cr, but contains:

[0089]

[0090] The total amount of TiO2 and Nb2O5 is 0.1-10% by mass.

[0091] And preferably,

[0092] The content ratio of TiO2 (TiO2 / (TiO2+Nb2O5)) relative to the total content ratio of TiO2 and Nb2O5 is 0 to 0.5, and includes:

[0093]

[0094]

[0095] The base glass component of the ultraviolet-transmitting visible-light-absorbing optical glass according to the present invention is not particularly limited, but is preferably soda-silica glass or sodium-potassium-barium glass.

[0096] The ultraviolet-transmitting visible light absorbing glass according to the present invention is preferably in a plate-like state with a thickness of 3 mm, and is irradiated with a light source having a maximum radiation intensity at a wavelength of 365 nm at a power of 500 mW·cm -2 When irradiation light including ultraviolet light and visible light (irradiation light in a wavelength range of 200nm to 700nm) is irradiated with a radiation intensity of 1000nm, the maximum value of the transmittance in the wavelength range of 350 to 370nm at the start time of the irradiation of the above-mentioned irradiation light is greater than 75%.

[0097] On the other hand, the ultraviolet-transmitting visible light absorbing glass according to the present invention is preferably in a plate-like state with a thickness of 3 mm, and is irradiated with a light source having a maximum radiation intensity at a wavelength of 365 nm at a power of 500 mW·cm -2 When irradiation light including ultraviolet light and visible light (irradiation light in a wavelength range of 200 nm to 700 nm) is irradiated with a radiation intensity of, the light transmittance in the wavelength range of 200 to 290 nm at the start of irradiation of the irradiation light is 1% or less.

[0098] Furthermore, the ultraviolet-transmitting visible light absorbing glass according to the present invention is preferably in a plate-like state with a thickness of 3 mm, and is irradiated with a light source having a maximum radiation intensity at a wavelength of 365 nm at a power of 500 mW·cm -2 When irradiated with irradiation light including ultraviolet light and visible light (irradiation light in a wavelength range of 200nm to 700nm) with a radiation intensity of 1%, the transmittance in the wavelength range of 410 to 690nm at the start of irradiation of the above-mentioned irradiation light is less than 1%, and more preferably the transmittance in the wavelength range of 450 to 650m is less than 0.1%.

[0099] The ultraviolet-transmitting visible light absorbing glass of the present invention does not substantially contain Pb, As, Cd and Cr, but contains CoO, NiO, TiO2, and Nb2O5 in specified amounts, thereby reducing the environmental load while selectively exhibiting high transmittance in the wavelength range of 350 to 370 nm.

[0100] The ultraviolet-transmitting visible light absorbing glass according to the present invention is preferably in a plate-like state with a thickness of 3 mm, and is irradiated with a light source having a maximum radiation intensity at a wavelength of 365 nm at a power of 500 mW·cm -2 When the irradiation light including ultraviolet light and visible light is irradiated for 100 hours, the maintenance rate represented by the following formula (I) is 90% or more:

[0101] (B / A)×100(I)

[0102] Among them, A is the maximum value (%) of the transmittance in the wavelength range of 350 to 370 nm at the start of the irradiation of the irradiation light, and B is the maximum value (%) of the transmittance in the wavelength range of 350 to 370 nm at the moment 100 hours after the start of the irradiation of the above-mentioned irradiation light.

[0103] In the present application, the plate-shaped glass used for measuring the above-mentioned light transmittances has both surfaces optically polished, and the above-mentioned light transmittances represent values ​​measured when irradiation light is incident perpendicularly to the surface subjected to the above-mentioned optical polishing.

[0104] The ultraviolet-transmitting visible light absorbing glass involved in the present invention does not substantially contain Pb, As, Cd and Cr, but contains CoO, NiO, TiO2, and Nb2O5 in specified amounts respectively, thereby reducing the environmental load, selectively exhibiting high transmittance in the wavelength range of 350 to 370 nm, and can appropriately suppress degradation caused by overexposure.

[0105] The method for producing the ultraviolet-transmitting visible light absorbing glass according to the present invention is not particularly limited, and any currently used method may be appropriately adopted.

[0106] For example, oxides, hydroxides, carbonates, nitrates, chlorides, sulfides, etc. are used as glass raw materials, and they are weighed and mixed in a manner to obtain the desired composition as the blending raw materials. The obtained blending raw materials are placed in a heat-resistant crucible and melted, stirred, and clarified at a temperature of about 1300 to 1400°C to form a homogeneous molten glass. Then, the molten glass is injected into a molding frame, and after forming a glass block, it is moved into a furnace heated to a temperature close to the slow cooling point of the glass and cooled to room temperature, thereby obtaining a block of the target ultraviolet-transmitting and visible-light-absorbing glass.

[0107] According to the present invention, it is possible to provide an ultraviolet-transmitting visible light absorbing glass which selectively improves the transmittance of irradiation light in the wavelength range of 350 to 370 nm while reducing environmental load and suppressing degradation due to overexposure.

[0108] Next, the ultraviolet-transmitting visible light absorbing filter according to the present invention will be described.

[0109] The ultraviolet-transmitting visible-light-absorbing filter according to the present invention is characterized in that it is composed of the ultraviolet-transmitting visible-light-absorbing glass according to the present invention.

[0110] The details of the ultraviolet-transmitting visible light absorbing glass according to the present invention are as described above.

[0111] As the ultraviolet-transmitting visible light absorption filter according to the present invention, plate-shaped glass having both surfaces optically polished can be exemplified.

[0112] As the ultraviolet-transmitting visible light absorbing filter according to the present invention, an antireflection film or other optical multilayer film may be applied to the ultraviolet-transmitting surface of the filter (for example, the optically polished double surfaces mentioned above).

[0113] The method for producing the ultraviolet-transmitting visible-light-absorbing filter according to the present invention is not particularly limited, and the filter can be produced by processing the ultraviolet-transmitting visible-light-absorbing glass according to the present invention using a known processing method.

[0114] The ultraviolet-transmitting visible-light absorbing filter according to the present invention is composed of the ultraviolet-transmitting visible-light absorbing glass according to the present invention, and since it does not contain components such as Pb, As, Cd and Cr, it can reduce the environmental load caused by cutting chips and waste water.

[0115] The ultraviolet-transmitting visible light absorption filter of the present invention can be suitably used as an ultraviolet-transmitting filter incorporated in ultraviolet irradiation devices such as semiconductor exposure equipment and light sources for ultraviolet-curing resins.

[0116] According to the present invention, there can be provided an ultraviolet-transmitting visible light absorption filter which reduces environmental load, selectively exhibits high light transmittance in the wavelength range of 350 to 370 nm, and can suppress degradation due to overexposure.

[0117] Example:

[0118] Hereinafter, the present invention will be further described using examples and comparative examples, but the present invention is not limited to the following examples.

[0119] (Example 1 to Example 4, Comparative Example 1 to Comparative Example 2)

[0120] In order to obtain glass having the composition described in Tables 1 and 2, cobalt oxide (CoO), nickel hydroxide (Ni(OH)2), titanium oxide (TiO2) and niobium oxide (Nb2O5) are weighed respectively, and silica powder (SiO2), boric acid (H3BO3), aluminum hydroxide (Al(OH)3), sodium carbonate (Na2CO3), sodium nitrate (NaNO3), potassium carbonate (K2CO3), calcium carbonate (CaCO3), zinc oxide (ZnO), barium carbonate (BaCO3), antimony oxide (Sb2O3), and cerium oxide (CeO2) are weighed respectively, and the mixed raw materials are put into a platinum crucible, heated, melted, and stirred at 1300 to 1400°C in the atmosphere, and then homogenized and clarified and poured into a casting mold. After the glass solidifies, it is further transferred to an electric heating furnace heated to a temperature close to the slow cooling point of the glass and slowly cooled to room temperature, thereby obtaining the target glass.

[0121] (Example 5)

[0122] In order to obtain glasses having the compositions shown in Tables 1 and 2, the target glass was obtained in the same manner as in Example 2 except that a viscosity crucible was used instead of a platinum crucible.

[0123] Table 1 shows the content ratio of each component constituting each glass, the total content ratio of each component and the content ratio based on mass %, and Table 2 shows the content ratio of each component constituting each glass, the total content ratio of each component and the content ratio based on mol %.

[0124] The glasses obtained from Examples 1 to 5 and Comparative Examples 1 to 2 were processed into plates with a thickness of 3 mm and optically polished on both sides. The spectral transmittance at wavelengths of 200 to 700 nm was measured using an ultraviolet visible spectrophotometer (UV3600 manufactured by Shimadzu Corporation).

[0125] Then, an ultraviolet light source (UL750 manufactured by HOYA CANDEO OPTRONICS Co., Ltd.) with a maximum radiation intensity at a wavelength of 365 nm was used to irradiate the irradiated surface from a direction perpendicular to the surface subjected to the optical polishing, with a radiation intensity of 500 mW·cm -2 Irradiation light including ultraviolet light and visible light (measured at the irradiated surface using an ultraviolet intensity meter UIT-101 manufactured by "USHIO Corporation").

[0126] The maximum value of the light transmittance of the plate-like objects obtained from the glasses obtained in Examples 1 to 5 to the irradiation light in the wavelength range of 350 to 370 nm was 75% or more before irradiation with the irradiation light.

[0127] In addition, the light transmittance of the plate-like objects obtained from the glasses obtained in Examples 1 to 5 in the wavelength range of 200 to 290 nm and the light transmittance in the wavelength range of 410 to 690 nm before irradiation with the irradiation light were both 1% or less.

[0128] When the above-mentioned irradiation light is continuously irradiated for 100 hours, the maximum value of the transmittance in the wavelength range of 350 to 370 nm before the irradiation of the irradiation light (Tmax initial) and the maximum value of the transmittance in the wavelength range of 350 to 370 nm at the moment 100 hours after the start of the irradiation of the irradiation light (Tmax100hr) are recorded in Tables 1 and 2, respectively.

[0129] In addition, the maintenance rates (%) calculated by the above (Tmax 100hr / Tmax initial)×100 are shown in Tables 1 and 2, respectively.

[0130] Figure 1 The transmission spectrum (a) at the start of irradiation and the transmission spectrum (b) 100 hours after the start of irradiation are shown when the plate-like object obtained from the glass obtained in Example 1 is irradiated with the irradiation light, and Figure 2When a plate-like object obtained from the glass obtained in Example 2 is irradiated with the irradiation light, a transmission spectrum (a) at the start of irradiation and a transmission spectrum (b) after 100 hours from the start of irradiation are shown.

[0131] also, Figure 3 When a plate-like object obtained from the glass obtained in Example 5 is irradiated with the irradiation light, a transmission spectrum (a) at the start of irradiation and a transmission spectrum (b) after 100 hours from the start of irradiation are shown.

[0132] also, Figure 4 The transmission spectrum (a) at the start of irradiation and the transmission spectrum (b) 100 hours after the start of irradiation are shown when the plate-like object obtained from the glass obtained in Comparative Example 1 is irradiated with the irradiation light, and Figure 5 When the plate-like object obtained from the glass obtained in Comparative Example 1 was irradiated with the irradiation light, the transmission spectrum (a) at the start of irradiation and the transmission spectrum (b) after 100 hours from the start of irradiation are shown.

[0133] like Figure 1 to Figure 3 As shown in the transmission spectrum (a) at the start of irradiation and the transmission spectrum (b) 100 hours after the start of irradiation, it can be seen that a 3 mm thick plate made of the glass obtained in each example has a high thermal conductivity even when irradiated with 500 mW·cm from a light source having a maximum radiation intensity at a wavelength of 365 nm. -2 The irradiation intensity of the irradiation light including ultraviolet light and visible light was irradiated for 100 hours. Before and after the irradiation, high transmittance was also shown in the wavelength range of 350 to 370 nm. As shown in Tables 1 and 2 below, the light source with the maximum irradiation intensity at a wavelength of 365 nm was irradiated with 500 mW·cm -2 When the radiation intensity of the irradiation light including ultraviolet light and visible light is irradiated for 100 hours, it can be seen that the maintenance rate of ultraviolet light transmittance expressed by the formula (B / A)×100 (wherein A is the maximum value (%) of the transmittance within the wavelength range of 350 to 370 nm at the start of the irradiation of the irradiation light, and B is the maximum value (%) of the transmittance within the wavelength range of 350 to 370 nm at the moment 100 hours have passed since the start of the irradiation of the irradiation light) is as high as over 90%.

[0134] Table 1

[0135]

[0136] Table 2

[0137]

[0138] It can be seen from Table 1, etc. that the ultraviolet-transmitting visible light absorbing glass obtained by Examples 1 to 5 does not substantially contain Pb, As, Cd and Cr, but contains specified amounts of CoO, NiO, TiO2 and Nb2O5 respectively, thereby reducing the environmental load while selectively improving the transmittance of irradiated light in the wavelength range of 350 to 370 nm, and can suppress degradation caused by overexposure. Therefore, it can be appropriately used for ultraviolet-transmitting visible light absorbing filters.

[0139] On the other hand, according to Tables 1 and 2, etc., it can be seen that the glasses obtained from Comparative Examples 1 and 2 do not contain Nb2O5, so the maximum value of the transmittance (Tmax initial) in the wavelength range of 350 to 370 nm at the start of irradiation of the irradiated light will decrease (Comparative Example 2), or the degradation caused by overexposure cannot be suppressed (Comparative Example 1, Comparative Example 2).

[0140] Industrial Applicability

[0141] According to the present invention, there can be provided an ultraviolet-transmitting visible light absorbing glass which selectively improves the transmittance of irradiated light in the wavelength range of 350 to 370 nm while reducing environmental load, thereby suppressing degradation caused by overexposure, and an ultraviolet-transmitting visible light absorbing filter composed of the glass.

Claims

1. An ultraviolet-transmitting visible light absorbing glass, characterized in that: It contains essentially no Pb, As, Cd and Cr, but contains: CoO 0.1-2 mass%, NiO 1-5 mass%, TiO2 0-1 mass%, Nb2O5 0.1~10 mass%, Na2O 5-6 mass%, BaO 11-15% by mass The total content of TiO2 and Nb2O5 is 0.1 to 10% by mass; In the state of a plate with a thickness of 3 mm, a light source with a maximum radiation intensity of 500 mW·cm is used to irradiate the -2 When irradiation light including ultraviolet light and visible light is irradiated with a radiation intensity of, the maximum value of the light transmittance in the wavelength range of 350 to 370 nm at the start time of irradiation of the irradiation light is 75% or more.

2. The ultraviolet-transmitting visible light absorbing glass according to claim 1, characterized in that: The content ratio of TiO2 (TiO2 / (TiO2+Nb2O5)) is 0 to 0.5 relative to the total content ratio of TiO2 and Nb2O5.

3. The ultraviolet-transmitting visible light absorbing glass according to claim 1, characterized in that: Also includes:

4. The ultraviolet-transmitting visible light absorbing glass according to claim 1, characterized in that: In the state of a plate with a thickness of 3 mm, a light source with a maximum radiation intensity of 500 mW / cm -2 When irradiation light including ultraviolet light and visible light is irradiated with a radiation intensity of 1000 nm, the transmittance in the wavelength range of 200 to 290 nm and the transmittance in the wavelength range of 410 to 690 nm at the start of irradiation of the irradiation light are both less than 1%.

5. The ultraviolet-transmitting visible light absorbing glass according to claim 1, characterized in that: In the state of a plate with a thickness of 3 mm, a light source with a maximum radiation intensity of 500 mW / cm -2 When the irradiation light including ultraviolet light and visible light is irradiated for 100 hours, the maintenance rate represented by the following formula (I) is 90% or more: (B / A)×100 (I) Among them, A is the maximum value of the transmittance in the wavelength range of 350 to 370 nm at the start of the irradiation of the irradiation light, and B is the maximum value of the transmittance in the wavelength range of 350 to 370 nm at the time when 100 hours have passed since the start of the irradiation of the irradiation light.

6. An ultraviolet light transmission visible light absorption filter, characterized in that: The invention is composed of the ultraviolet-transmitting visible light absorbing glass according to any one of claims 1 to 5.

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