Filter glass

Abstract

To provide a filter glass that solves the problems of the conventional art.SOLUTION: A filter glass comprises more than 1.1 mass% to 6.0 mass% of Li2O, and at least one additional component selected from Na2O and K2O, and also comprises the following composition (expressed in mass% based on oxide): P2O5 of 55.0 to 75.0; Al2O3 of 4.1 to 8.0; CuO of 8.0 to 18.0; V2O5 of 0 to less than 0.8; SiO2 of 2.0 or less; F of 2.0 or less; R'O (R'=Mg, Ca, Sr, Ba, Zn) of 0 to 11.0 in total; and R2O (R=Li, Na, K) of 3.0 to 17.0 in total.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to blue-colored filter glass, particularly phosphate glass, for use as a filter, and to the manufacture of the same. [Background technology]

[0002] The types of filter glass described above can be used as so-called optical bandpass filters, that is, filters having a more or less narrow wavelength range of high transmittance (transmission range) surrounded by two blocking ranges with very low transmittance. Such glass is used as optical glass filters, for example, as color correction filters in color video cameras, digital cameras, and smartphone cameras. A further application area is filters for blocking near-infrared (NIR) rays from LEDs in displays, for example. For such glass, in addition to high transmittance in the wavelength range of approximately 400 to 600 nm, especially 430 to 565 nm, a steep edge in the UV range below 400 nm, i.e., a sharp decrease in transmittance, and very low transmittance at wavelengths above 700 nm are desirable. It is also desirable that the transmittance curve decreases as sharply as possible with respect to the NIR range of the spectrum.

[0003] Furthermore, NIR blocking filters are used in the aerospace / navigation sector because precise color positioning is required during strong blocking (e.g., white or green color positioning). For example, the UV range should be blocked as completely as possible to avoid damage to sensitive electronic systems from high-energy light, while the intensity of incident light above 700 nm should be reduced to compensate for redness in images caused by CCD (charge-coupled device) sensors, for example, when used in cameras.

[0004] For use as filters, copper oxide-containing fluorophosphate glasses are known from the prior art (e.g., German Patent Application Publication No. 102012210552 (DE 10 2012 210 552 A1), German Patent Application Publication No. 102011056873 (DE 10 2011 056 873 A1)). However, these glasses often have the disadvantage of being difficult to manufacture due to their very high fluorine content, because fluorine itself and the fluorides of many glass components are volatile under normal manufacturing conditions. 13×10 -6 Due to their relatively high coefficient of thermal expansion (measured in the temperature range of 20-300°C) exceeding 1K, processing, post-processing, and / or further processing (e.g., cutting, polishing, and bonding in the range of "wafer-level packaging") of fluorophosphate glass are extremely difficult and cumbersome. For example, if the glass needs to be fixed for this purpose, there is a high risk of fracture due to thermally induced mechanical stress. Therefore, much effort has been made to optimize the composition of fluorophosphate glass with the aim of obtaining glass that is both highly resistant and available through economical manufacturing methods.

[0005] Furthermore, copper oxide-containing phosphate glasses that are nearly fluorine-free are known for use as filter glasses (e.g., U.S. Patent Application Publication No. 2007 / 0099787 (US2007 / 0099787 A1), German Patent No. 4031469 (DE 40 31 469 C1), German Patent No. 102017207253 (DE 102017207253 B3), Chinese Patent Application Publication No. 110255886 (CN 110255886 A), Chinese Patent Application Publication No. 110194592 (CN 110194592 A)). Indeed, such glasses can be processed better than fluorophosphate glasses due to their lower coefficient of thermal expansion. However, its weather resistance (also called "climate stability") is usually worse than that of fluorophosphate glass. Furthermore, the raw materials for such glass have high melting points and, consequently, high melting temperatures; that is, the raw materials for this glass often only melt at temperatures far above 1100°C (e.g., above 1200°C), which is problematic. At such high temperatures, the equilibrium of various oxidation states of copper (i.e., Cu(II):Cu(I):Cu(O)) has already shifted to lower oxidation states. This presents several disadvantages for filter applications, especially at high concentrations of copper oxide. On the one hand, the high transmittance at the UV edge is exacerbated by a high proportion of monovalent copper (Cu(I); Cu2O). On the other hand, elemental copper (Cu(O)) is increasingly formed, which alloys with platinum-based components, making them thermally unstable, leading to platinum intrusion into the glass, further worsening transmittance at the UV edge, and causing the platinum structural components to break down. In the case of known phosphate glasses, the addition of oxidizing agents, such as CeO2, MnO2, Cr2O3, and V2O5, is considered necessary to stabilize a higher oxidation state at certain ions, such as copper ions (e.g., U.S. Patent Application Publication 2007 / 0099787, German Patent No. 4031469).

[0006] As components for electronic devices become increasingly smaller, there is a growing demand for very thin filters, i.e., filters having a thickness of 0.21 mm or less, for example, a filter having a thickness of about 0.11 mm. For this purpose, the glass must be strongly colored. With a higher CuO content, the steepness of the transmittance curve for the NIR range of the spectrum can be improved, but on the other hand, this changes the equilibrium of the Cu(II):Cu(I) species, resulting in the presence of more Cu(I), which in turn reduces the transmittance in the transmission range of the filter glass.

[0007] Furthermore, a high content of CuO causes problems in glass production because coloring components such as CuO not only act as coloring components as the content increases, but also Cu(I) ions and Cu(II) ions, as components of the glass, compete with alkali metal ions and alkaline earth metal ions for sites present in the glass network, thereby affecting the structure of the glass and other physical properties of the glass.

[0008] When used for optical filters of copper-containing phosphate glasses, in the case of very good optical properties, there have been limitations regarding several things. One is that phosphate glasses have only limited weather stability, and the other is that the mechanical strength is partially insufficient. Furthermore, regarding the composition, there are several conflicting goals. Al2O3 and SiO2 can improve the weather resistance of phosphate glasses on the one hand, but on the other hand, they have the above-mentioned adverse effects on the equilibrium of copper species and contribute to an increase in the melting temperature. The presence of alkali ions results in a glass having a lower melting temperature, which is advantageous for the copper species equilibrium, but on the other hand, the weather resistance of the glass deteriorates depending on the proportion of the alkali.

[0009] Furthermore, the increasing miniaturization of optical components requires an even thinner filter thickness, which clearly requires a high CuO concentration to produce the required optical properties. However, a higher CuO content causes the problems shown above.

Prior Art Documents

Patent Document

[0010] [[ID=]7]

Patent Document 1

Patent Document 2

[0015] The glass according to the present invention appears blue, blue-green, turquoise, or cyan to the human eye, and can appear black with greater thickness and higher CuO content, and can be used as an IR cut filter. In this case, color is not important for many applications. Rather, the filtering properties due to absorption of UV up to about 300 nm and near-infrared (NIR) at about 850 nm by adding a colored oxide CuO are decisive for applications as a filter, for example, as a filter in front of a digital camera sensor. In this case, UV blocking is caused by the base glass itself as well as CuO. To keep the UV transmittance as high as possible above wavelengths of 400 nm and above, especially above 430 nm (because shorter wavelengths are no longer visually perceptible to humans), an oxidizing agent, such as a nitrate and / or vanadium oxide (V2O5), may be used.

[0016] In a favorable embodiment, the filter glass comprises the following in mass%: [Table 2]

[0017] In a further advantageous embodiment, the filter glass comprises the following in mass %: [Table 3]

[0018] In a further advantageous embodiment, the filter glass comprises the following in mass %: [Table 4]

[0019] According to the present invention, the glass contains phosphate (P2O5) in a proportion of 55.0 to 75.0% by mass. As a glass-forming agent, the phosphate content in the glass according to the present invention is at least 55.0% by mass. This lower limit should not be lowered because a high proportion of CuO for very thin NIR cut filters requires a high proportion of network-forming components for stabilization against separation. A more favorable lower limit can be at least 58.0% by mass, preferably at least 59.0% by mass, preferably at least 60.0% by mass, preferably at least 61.0% by mass, and particularly preferably at least 62.0% by mass. The upper limit of the phosphate content, according to the present invention, is a maximum of 75.0% by mass. This upper limit should not be exceeded because otherwise the stability of the glass against humidity may deteriorate. At higher P2O5 content, the hygroscopic properties become more pronounced, which can lead to swelling and turbidity of the glass, as well as the formation of a large salt layer on the surface. An advantageous embodiment of the glass has a maximum of 75.0% by mass, or a maximum of 74.0% by mass, or a maximum of 73.0% by mass, of P2O5. For variants with a high P2O5 content, an advantageous lower limit for the phosphate content may be at least 65.0% by mass, or at least 66.0% by mass, or at least 67.0% by mass, or at least 68.0% by mass. For advantageous variants with a lower P2O5 content, an advantageous upper limit may be at least 70.0% by mass, or at least 69.0% by mass.

[0020] Aluminum oxide (Al2O3) is used to enhance the weather resistance stability of glass because, although it is a conditional network-forming agent, it is not hygroscopic. Furthermore, it improves the adhesion of functional coatings subsequently applied to the filter glass, such as anti-reflective coatings or other interference layers, and simultaneously protects the surface of the filter glass from moisture. Al2O3 is contained in the glass according to the present invention in an amount of 4.1 to 8.0 mass%. To obtain sufficient weather resistance stability, the lower limit should not be lowered to 4.1 mass%. Advantageously, at least 4.3 mass% or at least 4.5 mass% or at least 4.7 mass% of Al2O3 can be contained in the glass. Some advantageous variants may also contain at least 5.0 mass% of Al2O3. The upper limit should not be exceeded to 8.0 mass% because a higher Al2O3 content increases the crystallization tendency of the glass, particularly the melting range of the glass. Glass with a higher melting range also has a higher melting temperature for the mixture. A higher melting temperature allows the molten material to reach the reducing range. As a result, the equilibrium of components (e.g., Cu, V) that can result in various oxidation states in the molten material shifts to a lower oxidation state. However, this undesirably alters the optical properties of the glass (e.g., absorption, transmission), and consequently, its characteristic filter properties. It is advantageous when the aluminum oxide content is up to 7.5 mass%, more preferably up to 7.0 mass%, or up to 6.7 mass%, or up to 6.5 mass%, or up to 6.3 mass%. For some advantageous variants, the upper limit for the Al2O3 content may be up to 6.0 mass%.

[0021] To ensure sufficient stability in the glass of the present invention, the proportion of the glass-forming agent, i.e., the sum of phosphate and aluminum oxide (P2O5 + Al2O3), can be advantageously at least 63.0% by mass. The advantageous upper limit for the sum of phosphate and aluminum oxide can be up to 81.0% by mass. Within this broad range, advantageous variants can be distinguished, one variant having a relatively low P2O5 + Al2O3 sum of 63.0% to less than 72.0% by mass, and another variant having a relatively high P2O5 + Al2O3 sum of 72.0% to 81.0% by mass.

[0022] For variants having a relatively low total of P2O5 + Al2O3, a favorable lower limit may be at least 65.0 mass%, or at least 67.0 mass%, and / or a favorable upper limit may be at least 71.5 mass%, or at least 71.0 mass%.

[0023] For variants having a relatively high total of P2O5 + Al2O3, a favorable lower limit may be at least 73.0 mass%, or at least 74.0 mass%, and / or a favorable upper limit may be at least 80.0 mass%, or at least 79.0 mass%.

[0024] Furthermore, it has been found to be advantageous to adjust the weight or mass ratio of phosphate to aluminum oxide to a value of at least 8, preferably at least 9, preferably at least 10, and / or preferably up to 16. In a more preferred embodiment, this value is up to 15, preferably up to 14.

[0025] Silicon oxide (SiO2), like aluminum oxide, increases the crystallization tendency and melting temperature range of glass and degrades the optical properties of glass by shifting the equilibrium of copper oxidation states. Therefore, if present, it should be included in the glass at a maximum of 2.0 mass%, preferably less than 2.0 mass%. Advantageously, the glass according to the present invention contains less than 1.5 mass%, advantageously a maximum of 1.0 mass%, and preferably less than 1.0 mass% of SiO2. The lower limit for SiO2 can be at least 0.01 mass%. Particularly preferably, the glass may be SiO2-free. Small percentages of less than 1.5 mass% may be included due to contamination of the raw materials and / or due to the manufacturing process in a SiO2-containing melting bath. However, as already explained above with respect to Al2O3, SiO2 may be intentionally used in the glass within the limits indicated above to improve the adhesion of functional coatings later applied to the filter glass. Good adhesion helps prevent the applied coating from peeling off the glass surface over time.

[0026] As stated at the beginning, the filter glass according to the present invention is included in blue filters or IR-blocking filters. Therefore, it contains copper oxide (CuO) in an amount of 8.0 to 18.0 mass% as a coloring component. If too little copper oxide is used (i.e., below the lower limit of 8.0 mass% according to the present invention), the light-blocking effect or light ray-blocking effect in NIR for the purposes of the present invention is insufficient because the absorption of Cu in the glass is too low when the glass thickness is thin (e.g., 0.205 mm or 0.11 mm). It is advantageous for the glass to contain more than 8.0 mass%, advantageously at least 8.5 mass% or at least 9.0 mass% CuO. Some advantageous variations may also contain at least 9.5 mass% or at least 10.0 mass% CuO. Naturally, the filter glass has other requirements, such as reference thickness, transmittance, blocking and T 50It is well known to those skilled in the art that when requirements regarding values ​​are imposed, the CuO content may be reduced according to the target setting, that is, a content of less than 8.0% by mass may be used for the disclosed base glass.

[0027] Within the scope of the present invention, P2O5, Al2O3, R2O components, and optionally present components, such as R'O, SiO2, B2O3, La2O3, and Y2O3, form the base glass of the filter glass. The characteristic filter properties are adjusted through the addition of coloring components. These coloring components include CuO in particular, but also V2O5 and CeO2 if present, because these components affect the oxidation-reduction state of CuO and, consequently, its absorption. Therefore, while all components other than the coloring components, and if present, the fining agents and F component (which are useful for adjusting color and quality or process), are present in the base glass, the composition of the base glass remains essentially the same.

[0028] However, if too high a proportion of copper oxide is selected, it will negatively affect the transmittance of the glass because the absorption of Cu(I) in UV light will become too strong, or the glass will become opaque due to Cu(O). Therefore, the upper limit of CuO should not be exceeded at 18.0 mass%. It may be advantageous for the glass to contain a maximum of 17.0 mass%, preferably 16.0 mass%, more preferably 15.0 mass%, or 14.0 mass% CuO.

[0029] To adjust the UV transmittance to the highest possible level, the glass according to the present invention may preferably contain vanadium oxide (V2O5) in a proportion of 0 to <0.8 mass%. When vanadium oxide is present, the lower limit may be at least 0.01 mass%, or at least 0.03 mass%, or at least 0.05 mass%. It should not exceed the upper limit of less than 0.8 mass%, preferably a maximum of 0.7 mass%, or a maximum of 0.6 mass%, or a maximum of 0.5 mass%, because higher concentrations may result in absorption in the visible spectrum. Variations without V2O5 are also possible.

[0030] The glass according to the present invention contains lithium oxide (Li2O) in a proportion of more than 1.1% by mass and 6.0% by mass. In an advantageous embodiment, at least 1.2% by mass of Li2O, or in an advantageous variant, at least 1.5% by mass, or at least 1.6% by mass, can also be an advantageous lower limit. In some variants, it may be advantageous to contain at least 2.0% by mass of Li2O.

[0031] Since lithium ions have a similar ionic radius to Cu(I) ions, they compete with Cu(I) ions in the glass network. Therefore, by a higher content of Li2O (i.e., >1.1 mass%, or preferably more), it can be achieved that the sites for Cu(I) ions in the glass network are blocked by lithium ions. This shifts the redox equilibrium of the copper species towards Cu(II), thereby increasing the transmittance at the UV edge and the average transmittance in the range of 430-565 nm T avg This will be enhanced.

[0032] It may be advantageous to not exceed the upper limit of Li2O of 6.0 mass%, preferably 5.5 mass%, or 5.0 mass%, because otherwise the glass may become unstable and its climate resistance may deteriorate.

[0033] The glass of the present invention contains, in addition to Li2O, at least one further component selected from potassium oxide (K2O) and sodium oxide (Na2O), i.e., at least two alkali metal oxides R2O. The alkali metal oxides contribute to lowering the melting temperature of the glass. The purpose of using alkali metal oxides is to obtain a mixture that melts at the lowest possible temperature despite the relatively high Al2O3 content for phosphate glass, thereby suppressing the formation of monovalent or elemental copper as much as possible. Furthermore, the alkali metal oxides act as fluxes in the molten material, thus facilitating the processing of the glass by reducing its viscosity. However, too much of this oxide lowers the glass transition temperature, impairing the durability of the glass, such as its climate resistance, and increasing its thermal expansion coefficient. If the latter is particularly high, the glass can no longer undergo optimal cold post-treatment. Furthermore, its heat resistance decreases, and the relaxation of the glass in the annealing furnace becomes difficult. High alkali metal oxide content enhances the hygroscopic tendency of P2O5 in these glasses, which not only makes them more susceptible to salt efflorescence but also causes them to absorb a large amount of water and expand significantly.

[0034] Therefore, the total proportion of alkali metal oxides (i.e., the sum of R2O (R=Li, Na, K)) should not be less than 3.0 mass%, preferably 3.5 mass%, and preferably 4.0 mass%. For some variants, at least 5.0 mass%, or at least 6.0 mass%, or at least 7.0 mass%, or at least 8.0 mass%, may also be favorable lower limits. To avoid compromising the stability of the glass, the total content of these oxides should not exceed 17.0 mass%, preferably 16.0 mass%, even more preferably 15.0 mass%, and depending on the particular variant of the glass, 14.0 mass%, or 13.0 mass%. For some favorable variants with relatively low R2O content, a maximum of 10.0 mass%, or a maximum of 9.0 mass%, may also be favorable upper limits.

[0035] The glass according to the present invention contains at least two representative substances from the group of alkali metal oxides lithium oxide (Li2O), potassium oxide (K2O), and sodium oxide (Na2O), namely Li2O, and at least one further component from R2O, for stabilization against devitrification. It has been found that the content of the at least one further component from R2O (i.e., Na2O and / or K2O) is at least 0.1% by mass, preferably at least 0.3% by mass or more, or at least 0.5% by mass, or at least 0.7% by mass, or at least 1.0% by mass.

[0036] Overall, it is advantageous to combine alkali metal oxides such as lithium oxide, sodium oxide, and potassium oxide because the combination provides a stabilizing effect on the glass in terms of the effect of the mixed alkalis. Therefore, an advantageous embodiment of the filter glass has Li2O, Na2O, and K2O.

[0037] However, glasses containing only two components from the R2O group, namely Li2O + Na2O or Li2O + K2O, can also be advantageous.

[0038] The potassium oxide content in the glass can be advantageously 0 to 11.0 mass%. K2O can be used to fine-tune the steepness of the edge of the transmittance curve with respect to the NIR range. Some advantageous glass variants use K2O as an additional R2O component other than Li2O. Advantageous lower limits for K2O can be at least 0.1 mass%, advantageously at least 0.3 mass%, or at least 0.5 mass%, or at least 0.7 mass%, or at least 1.0 mass%. With respect to K2O content, variants with high K2O content and variants with low K2O content can be distinguished. In the case of high K2O content glass, it is advantageous that the minimum amount of K2O does not fall below 3.0 mass%, because otherwise both climate resistance and the steepness of the NIR edge are adversely affected. Advantageously, the glass contains at least 4.0 mass%, preferably at least 5.0 mass%, of K2O. However, the potassium oxide content must not exceed a maximum of 11.0% by mass, preferably a maximum of 10.0% by mass, and preferably a maximum of 9.0% by mass. Otherwise, the chemical durability of the glass will be severely impaired. Modifications with lower K2O content contain less than 3.0% by mass, preferably a maximum of 2.0% by mass, or a maximum of 1.0% by mass of K2O. Some advantageous modification forms may be K2O-free, especially when they have a relatively high Li2O content. In this case, the NIR edge can exhibit a steep transition even without K2O.

[0039] The sodium oxide content in the glass can be advantageously 0 to 7.0% by mass. This component can be used to reduce the melting range of the manufactured glass. This component can also improve devitrification stability. Some advantageous glass variants use Na2O as an additional R2O component other than Li2O. The advantageous lower limit for Na2O can be at least 0.1% by mass, advantageously at least 0.3% by mass, or at least 0.5% by mass, or at least 0.7% by mass, or at least 1.0% by mass. Advantageously, the glass may contain at least 2% by mass, more preferably at least 3% by mass of Na2O. In this case, considering stability, the content should not exceed a maximum of 7.0% by mass, advantageously a maximum of 6.0% by mass, and preferably a maximum of 5.0% by mass. Advantageous glass variants with low Na2O content may contain up to 2% by mass, or up to 1% by mass of Na2O. Some advantageous variants may be Na2O-free.

[0040] In the case of the filter glass according to the present invention having a high CuO content, divalent cations, particularly alkaline earth metal oxides (e.g., MgO, CaO, BaO, SrO) cations, and / or ZnO cations, compete with Cu(II) ions for sites in the glass network if their respective components are present in the glass. Within the scope of the present invention, the sum of alkaline earth metal oxides (i.e., MgO, CaO, BaO, SrO) and ZnO is referred to as R'O, where R' = Mg, Ca, Ba, Sr, Zn. Therefore, the sum of R'O in the filter glass according to the present invention is limited to a maximum of 11.0% by mass, or a maximum of 10.5% by mass, or a maximum of 10.0% by mass, or a maximum of 9.5% by mass, so that more CuO can be contained in the glass. Some advantageous variants may also contain a maximum of 9.0% by mass, or a maximum of 8.0% by mass, or a maximum of 7.0% by mass, or a maximum of 7.0% by mass, of R'O. If the proportion of R'O in the phosphate glass is too high, the glass may become unstable.

[0041] On the other hand, alkaline earth metal oxides, namely magnesium oxide (MgO), calcium oxide (CaO), barium oxide (BaO), strontium oxide (SrO), and zinc oxide (ZnO), can help adjust viscosity and improve the meltability of the glass. Like alkali metal oxides, they are network-modifying components. In an advantageous embodiment of the glass according to the present invention, if R'O is contained, its content can be at least 0.1% by mass, preferably at least 0.5% by mass, preferably at least 1.0% by mass, and preferably at least 2.0% by mass. Variants without R'O are also possible.

[0042] In favorable variants, the limitations given for R'O relate to the total amount of MgO + ZnO. Favorably, the total amount of MgO + ZnO can be 1.0 to 8.0 mass%, preferably 2.0 to 7.0 mass%. Favorable upper and lower limits for the MgO and ZnO components are described below.

[0043] The MgO content in the filter glass can be 0 to 6.0% by mass.

[0044] Some advantageous variants contain at least magnesium oxide (MgO) from known alkaline earth metal oxides. For such variants, the advantageous range for MgO can be 1.0% to 5.0% by mass. Advantageous embodiments may contain at least 1.0% by mass, preferably at least 2.0% by mass, and preferably at least 3.0% by mass of MgO. The advantageous upper limit for MgO for some variants can be up to 5.0% by mass, and advantageously up to 4.0% by mass. Advantageously, in such variants, the R'O content can be essentially determined by MgO, i.e., CaO, BaO, SrO, and ZnO are present only in small proportions, if any. It can be advantageous when only MgO from alkaline earth metal oxides is contained in the filter glass. Particularly advantageous variants have no further components from the R'O group other than MgO. The advantages associated with this are further described below.

[0045] In other favorable variants, MgO is a relatively small component relative to the total R'O content. Such variants contain less than 1.0 mass%, preferably up to 0.7 mass%, or up to 0.5 mass%, or up to 0.3 mass% of MgO. MgO-free variants are possible and favorable.

[0046] Calcium oxide (CaO) is an optional component within the scope of the present invention, meaning that variations without CaO are possible. If CaO is present, this component is advantageously at most 3.0% by mass, more preferably at most 2.0% by mass, and more preferably at most 1.0% by mass, and / or advantageously at least 0.01% by mass, and more preferably at least 0.1% by mass. CaO is less desirable as a component of glass within the scope of the present invention because, based on its size and charge, calcium ions compete with copper ions for sites in the glass network. In the case of glass with a very high CuO content, excessively high CaO content may contribute to achieving the upper limit on glass separation more quickly.

[0047] Barium oxide (BaO) and / or strontium oxide (SrO) may be present in several advantageous variants, for example, in amounts of at least 0.01% by mass or at least 0.1% by mass, respectively. Where BaO is to be present, its upper limit is advantageously 11.0% by mass, advantageously 10.0% by mass, preferably 9.0% by mass, or 8.0% by mass. A variant with a high BaO content may contain at least 5.0% by mass of BaO. A variant with a low BaO content may contain less than 5.0% by mass of BaO. The same limitations apply correspondingly to SrO. It is known to those skilled in the art that a given amount of BaO can be replaced by SrO. Depending on the BaO content in the glass, in some variants, the absorption maximum of Cu(II) may shift to a higher wavelength within the NIR range, thus maintaining the same T 50More Cu(II) is needed to achieve the desired value. This results in a steeper NIR edge (due to the logarithmic relationship between transmission and absorption). In other words, while the component promotes edge steepness well, it also promotes the conversion of Cu(II) to Cu(I), which has the aforementioned drawbacks regarding average transmittance at the UV edge and in the transmission range.

[0048] A preferred variant of the filter glass according to the present invention is one with low levels of BaO and / or SrO, and advantageously, one that is BaO and / or SrO-free. In such a variant, BaO and / or SrO are less desirable components because they can result in lower stability to crystallization and inferior melting behavior in the glass compared to alkali metal oxides or MgO or CaO. Nevertheless, such a variant has a steep NIR edge.

[0049] Within the scope of this invention, zinc oxide (ZnO) can be used in filter glass at a content of 0 to 8 mass%, and may be useful, for example, for reducing the coefficient of thermal expansion, improving heat resistance, and improving the relaxation of the glass in an annealing furnace. There are advantageous variants in which ZnO is used in small amounts, less than 1.0 mass%, preferably up to 0.7 mass%, or up to 0.5 mass%. The advantageous lower limit can be at least 0.05 mass%. Variants without ZnO are possible and advantageous.

[0050] Other particularly advantageous variants contain at least 1.0 mass%, preferably at least 2.0 mass%, or at least 3.0 mass%, and / or preferably up to 8.0 mass%, or up to 7.0 mass%, or up to 6.5 mass%, or up to 6.0 mass% of ZnO. In such variants, the R'O content can be advantageously characterized essentially by ZnO, i.e., alkaline earth metal oxides are present only in small proportions, if any. Particularly advantageous variants have no further components from the R'O group other than ZnO.

[0051] Within the scope of this invention, it has been found that, on the one hand, it is important that there is an upper limit to the total R'O content, as described above. On the other hand, it has been found that the type and combination of glass components selected from R'O affect the optical properties of the filter glass, particularly the position and shape of the INIR edge of the transmittance curve. The R'O component, as a network modification component, defines the range of short-range order of the glass, i.e., its internal structure. Colored Cu(II) ions are placed in the remaining sites, and their absorption behavior is influenced by the "neighbors" surrounding each Cu(II) ion. The more heterogeneous the glass network, the more the individual absorption behavior of Cu(II) ions differs, and the broader the overall absorption band of the Cu(II) species becomes, which results in the NIR edge of the transmittance curve not transitioning too sharply and the blockage at 700 nm worsening. However, the simpler and more uniform the glass network is, the fewer different sites exist for Cu(II) ions under various ambient conditions, resulting in more uniform absorption behavior for individual Cu(II) ions, which leads to a steeper NIR edge and lower transmittance at 700 nm. The fewer different components from the R'O group present in the glass, the more uniform the glass network becomes.

[0052] To provide an improved base glass having a uniform glass network, it is advantageous for the filter glass to contain up to three components selected from the group R'O, i.e., a combination of BaO + CaO + ZnO, or a combination of BaO + CaO + MgO. Other advantageous filter glasses contain up to two components selected from the group R'O, i.e., a combination of BaO + CaO, BaO + MgO, or MgO + ZnO. A particularly preferred variant of the filter glass contains only one component from the group R'O, which is advantageously MgO or ZnO.

[0053] In a preferred modified form, ZnO and / or MgO are used in the filter glass because their ionic radii are the same as those of both Cu species, thus creating a suitable network structure into which CuO can be well incorporated without crystallization.

[0054] In a favorable embodiment of the filter glass, the R2O content selected as described above results in the site of the network suitable for Cu(I) ions being occupied by alkali metal ions, thereby increasing the average transmittance in the 430-565 nm range and improving the UV edge of the transmittance curve.

[0055] In order to reduce the coefficient of thermal expansion without destabilizing the filter glass, lanthanum oxide (La2O3) may be included in an advantageous embodiment of the glass of the present invention. La2O3 densifies the network, thereby improving chemical durability through reduced hygroscopicity. When La2O3 is included, its content is advantageously at least 0.01% by mass, advantageously at least 0.1% by mass, advantageously at least 0.5% by mass, and preferably at least 1.0% by mass. Since La2O3 is an expensive glass component, it is advantageous that its proportion does not exceed the upper limit of 4.0% by mass, advantageously at least 3.5% by mass, or 3.0% by mass. Some variants may be La2O3-free.

[0056] In order to reduce the coefficient of thermal expansion without destabilizing the filter glass, yttrium oxide (Y2O3) may be included in an advantageous embodiment of the glass of the present invention. This component helps to lower the melting temperature because it dissolves very well in the crude molten material and thus increases its proportion. When Y2O3 is included, its content is advantageously at least 0.01% by mass, advantageously at least 0.1% by mass, advantageously at least 0.5% by mass, and preferably at least 1.0% by mass. It can be advantageous if its proportion does not exceed the upper limit of 4.0% by mass, advantageously at least 3.5% by mass, or 3.0% by mass. Some variants may be Y2O3-free.

[0057] The glass according to the present invention may contain fluorine (F) in amounts up to 2.0 mass%, preferably less than 2.0 mass%, preferably up to 1.5 mass% or less than 1.5 mass%, or up to 1.0 mass% or less than 1.0 mass%. Some advantageous variants may contain up to 0.8 mass%, preferably up to 0.5 mass%, preferably up to 0.4 mass%, or up to 0.3 mass%, or up to 0.2 mass% of F. Some advantageous variants of the glass may be fluorine-free as an added glass component. If fluorine is to be included, the lower limit may be 0.01 mass%. In this case, using fluorine in the molten material can help dehydrate the molten material, which results in a denser glass network and, consequently, better glass stability, because mobile ions are less likely to penetrate or accumulate in the glass network. Fluorine certainly improves the weather resistance stability of phosphate glass. However, the glass manufacturing process is difficult to control due to the volatility of this component. Furthermore, the mechanical workability of glass is hindered by fluorine content because such glass has a high coefficient of thermal expansion. In addition, fluorine further shifts the absorption band of Cu(II) into the visible range (to shorter wavelengths), thereby T 50 The value is already achieved at relatively low CuO concentrations. However, in that case, based on the logarithmic relationship between absorption and permeation, a relatively high T 700 This results in a value that worsens the blocking at 700nm. Naturally, other requirements for the filter glass, such as reference thickness, transmittance, blocking and T 50 When requirements regarding values ​​are imposed, the fluorine content in the glass may be increased depending on the target setting, or it may be higher depending on the operation of the process, meaning that it is possible to have a content exceeding 2.0 mass% with respect to the disclosed base glass, as is well known to those skilled in the art.

[0058] Boron oxide (B2O3) has a tendency to volatilize similar to fluorine, so the boron oxide content must be very low. Furthermore, boron also has an adverse effect on weather resistance. According to the present invention, the boron oxide content is preferably at most 1.0% by mass. It is particularly preferable that the boron oxide content is at most 0.7% by mass or at most 0.5% by mass. According to an advantageous variant, the glass according to the present invention does not contain boron oxide as a glass component, i.e., the glass is free of B2O3. When B2O3 should be contained, 0.01% by mass can be the lower limit.

[0059] Within the scope of the present invention, surprisingly, a filter glass having the desired transmittance characteristics can be produced without adding components used because cerium oxide (CeO2), i.e., a component that absorbs UV light in the case of many known filter glasses of the type described at the beginning. That is, an advantageous embodiment is free of cerium oxide. The base glass, i.e., a phosphate glass having no coloring ions, has good optical properties without requiring CeO2. By this measure, stable adjustment of the NIR edge can be achieved in production, so the glass composition preferably has only two components, copper oxide and vanadium oxide, which can exist in various valences depending on the oxidation-reduction state of the melt. The adjustment must be accurate so that the tolerance of T 50 for the filter to be produced can be maintained. In contrast, when CuO, V2O5, and CeO2 are present in the glass, stable adjustment of the NIR edge itself can be clearly difficult in the case of continuous production. However, when CeO2 is present in the filter glass in a small amount, its content is less than 1.1% by mass, less than 0.65% by mass, less than 0.5% by mass. Filter glasses having an even lower content, i.e., less than 0.4% by mass, or less than 0.3% by mass, or less than 0.2% by mass, or less than 0.1% by mass, or less than 0.05% by mass, or less than 0.01% by mass of CeO2 are particularly preferred.

[0060] Advantageously, the glass according to the present invention is iron oxide (Fe2O3)-free because this oxide can adversely affect the transmittance properties of the glass and can also contribute to the redox equilibrium of CuO, making it difficult to control a stable process. However, if a selective embodiment contains iron oxide, its content is limited to a maximum of 0.25% by mass. Fe2O3 may enter the glass as an impurity through other components. In a preferred embodiment, the glass according to the present invention is free of further coloring oxides other than copper oxide, and in particular is free of cobalt oxide (CoO).

[0061] The glass according to the present invention is advantageous as a filter glass because it is free from other coloring components, such as Cr, Mn and / or Ni, and / or optically active components, such as laser active components, such as Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er and / or Tm. Furthermore, the glass is advantageously free from components harmful to health, such as oxides of As, Pb, Cd, Tl and Se. The glass according to the present invention is even more preferably free from radioactive components.

[0062] The glass according to the present invention is further advantageous in that it is free from rare earth metal oxides, such as niobium oxide (Nb2O5), ytterbium oxide (Yb2O3), gadolinium oxide (Gd2O3), and tungsten oxide (WO3) and / or zirconium oxide (ZrO2), with the exception that La2O3 and Y2O3 may be present as described above. Nb2O5 is sparingly soluble in the molten material. Furthermore, niobium is a polyvalent ion involved in the redox equilibrium in the molten material. If it is present in a low oxidation state, the glass may be discolored brown. Gadolinium oxide, tungsten oxide, zirconium oxide and / or ytterbium oxide may increase the risk of crystallization of the glass and raise the melting temperature.

[0063] According to one embodiment of the present invention, the glass according to the present invention is advantageously composed of at least 90% by mass, more preferably at least 95% by mass, and most preferably 99% by mass of the above components.

[0064] According to one embodiment, the glass consists of 90% by mass, preferably 95% by mass, and more preferably 97% by mass, of P2O5, Al2O3, R'O, R2O, CuO, and V2O5.

[0065] According to one embodiment, the glass consists of 95% by mass, preferably 98% by mass, and more preferably 99% by mass, of the components P2O5, Al2O3, R'O, R2O, CuO, V2O5, La2O3, and Y2O3.

[0066] According to one embodiment of the present invention, the glass according to the present invention is also advantageously free from other components not listed in the claims or specification, i.e., according to such embodiment, the glass consists essentially of the aforementioned components, in which any individual components listed as undesirable or less desirable may be excluded. Here, the expression "consists essentially of" means that the other components are present at best as impurities, but are not intentionally added to the glass composition as individual components.

[0067] In this specification, when it is stated that glass is free of a certain component or does not contain a particular component, it means that this component may be present in the glass as an impurity at most. This means that it is not added in an essential amount as a glass component, or is not added at all. According to the present invention, an essential amount is less than 100 ppm, preferably less than 50 ppm, and most preferably less than 10 ppm.

[0068] In the case of this glass, clarification is advantageously carried out preferentially through physical clarification, i.e., the glass is dilute at the melting temperature / clarification temperature, and bubbles can form. The addition of clarifying agents promotes the release or absorption of oxygen in the molten material. Furthermore, polyvalent oxides can interfere with redox behavior, thereby promoting the formation of Cu(II)O.

[0069] The glass according to the present invention may contain small amounts of conventional fining agents. Advantageously, the total amount of added fining agents is at most 1.0% by mass, more preferably at most 0.5% by mass. As a fining agent, at least one of the following components may be contained in the glass according to the present invention (by mass%): [Table 5]

[0070] As inorganic peroxides, for example, zinc peroxide, lithium peroxide, and / or alkaline earth peroxides can be used.

[0071] According to an advantageous embodiment of the present invention, the glass is As2O3-free because this component is considered problematic from an ecological standpoint.

[0072] The thermal expansion coefficient (α) of the filter glass was measured for a temperature range of 20 to 300°C. 20-300 ) is advantageous up to 13 x 10 -6 / K, more preferably up to 12.5 × 10 -6 / K, and especially preferably up to 12 × 10 -6 The coefficient of thermal expansion is / K. This avoids problems associated with heat-induced mechanical stress in post-processing and joining techniques. This increases the mechanical strength. The lower limit for the coefficient of thermal expansion is at least 9.5 × 10⁻⁶. -6 / K, to be favorable, at least 9.8 × 10 -6 / K, at least 10x10 to be advantageous -6 It can be / K.

[0073] The glass according to the present invention is advantageous in having as high a glass transition temperature or transition temperature (T g ) should have. g The lower the transition temperature, the weaker the glass network becomes and the more brittle the glass becomes, making it more susceptible to moisture. The higher the transition temperature, the higher the hardness of each phosphate glass. Therefore, the filter glass according to the present invention is advantageously above 350°C, preferably at least 375°C.

[0074] Furthermore, the glass according to the present invention has a melting range (<T3) which is as low as possible. Such glass also has a correspondingly low melting temperature for the raw materials of the mixture. That is, according to the present invention, the components of the glass are selected such that a mixture with as low a melting point as possible is obtained. The melting temperature of the mixture should preferably be less than 1250 °C, preferably at most 1200 °C, and for some variants preferably at most 1150 °C, or at most 1100 °C. This low melting temperature advantageously enables the melt to remain within the oxidation range and for mainly Cu(II) to be present. Thus, the formation of Cu(I) and metallic copper is suppressed. Thereby, glass with a high transmittance is obtained. Despite the high copper content, these filter glasses are cloud-free and do not have a copper mirror on the surface. Thereby, the glass according to the present invention can be produced not only in an individual crucible but also in a melting tank (i.e., a continuous unit).

[0075] An advantageous embodiment of the filter glass having the composition according to the present invention is characterized by good filter glass properties: An advantageous embodiment of the filter glass has an average transmittance T in the range of 430 to 565 nm when the reference thickness is 0.205 mm avg of at least 83%, preferably at least 85%, preferably at least 86%. Some advantageous variants of the filter glass have a T of at least 87% with respect to a reference thickness of 0.205 mm avg as well. Said T avg is a measure of the transmittance of the filter glass in the transmission range. In the scope of the present disclosure, the average transmittance for the wavelength range 430 to 565 nm is described. In this range, the average transmittance must be as high as possible.

[0076] The transmittance (T at 700 nm), which is a measure of the blocking in the NIR range 700The ratio is up to 12% relative to a reference thickness of 0.205 mm for favorable embodiments of the filter glass, favorably up to 11.5%, and for some favorable variants up to 11%, or up to 10.5%, or up to 10%. 50 In relation to the value (see below), T 700 The value is a measure of the steepness of the edges of the transmittance curve.

[0077] T 50 The value is the wavelength at which the transmittance of the filter glass is exactly 50% in the near-infrared (NIR) range. Advantageously, the filter glass having the composition according to the present invention exhibits a steep NIR edge and allows for stable adjustment of the NIR edge during continuous manufacturing, thus enabling the production of filters with acceptable T values ​​for each application field. 50 The tolerance can be maintained. A favorable embodiment is a T in the range of 610nm to 640nm for a reference thickness of 0.205mm. 50 It may have a value. Favorably, T 50 The value can be in the range of 618nm to 634nm, preferably in the range of 620 to 632nm, and preferably in the range of 622nm to 630nm.

[0078] The transmittance requirements for advantageous filter glass are, 50 The value may be 626nm±8nm, preferably 626nm±6nm, or preferably 626nm±4nm relative to a reference thickness of 0.205mm. Particularly preferred is T avg and T 700 The above restrictions apply to T 50 This requirement regarding the value is met. Particularly preferred is T avg and T 700 The above restrictions apply to T 50 This corresponds to a filter glass whose value is normalized to 626 nm. By changing (increasing or decreasing) the CuO content, T 50 The value can be adjusted to the target.

[0079] To enable comparison of the transmission and blocking behavior of the filter glass and to evaluate the position and shape of the absorption edge, the advantageous configuration of the filter glass is not only normalized with respect to a thickness of 0.205 mm, but also the filter glass is rated at 626 nm T 50 The composition is adapted to have a value.

[0080] Therefore, within the scope of this disclosure, the advantageous filter glass is a T with a reference thickness of 0.205 mm and 626 nm. 50 For a transmittance curve normalized to a specific value, the average transmittance T in the range of 430-565 nm is... avg A favorable filter glass is presented that has a transmittance of at least 83% and a maximum of 12% at 700nm, thus exhibiting a steep NIR edge. avg and T 700 Further advantageous limitations are as stated above. Such optical properties are achieved when the CuO content according to the present invention is adjusted in the base glass (phosphate glass having components from the group Al2O3, R2O, and R'O, and optionally further components as described below, in adjusted proportions). Other requirements for the filter glass, e.g., other reference thicknesses or other T 50 It is well known to those skilled in the art that, in the case of values, the CuO content in the glass must be adjusted to meet each specification.

[0081] The glass according to the present invention has sufficiently good climate resistance, climate tolerance, or weather resistance. Based on the composition of the base glass, good adhesion for functional coatings is obtained, which also contributes to the climate tolerance of the coated filter. Even if the edges are not protected in some cases, the filter glass in the coated filter is sufficiently resistant to moisture.

[0082] The glass according to the present invention has achieved the solution to the problems associated with the filter glass described at the beginning. It has been achieved to provide a sufficiently weather-resistant phosphate glass that has a very high CuO content while largely or completely eliminating fluorine. The lower coefficient of thermal expansion (compared to fluorophosphate glass) improves mechanical strength and reduces the risk of glass breakage during further processing. By determining the glass composition as intended and by specially selecting the raw materials (e.g., in the form of composite phosphates) to incorporate each glass component into the glass, the melting temperature is kept low during the manufacture of the glass. This makes it possible to incorporate a high CuO content into the glass, which is necessary to manufacture thinner filters, while still achieving good filter properties (transmittance and absorptance values). By selecting components from the R'O and R2O group as intended, a base glass is provided in which the equilibrium of Cu species shifts from Cu(I) to Cu(II), and the transmittance curve of the filter glass is optimized to have a steep NIR edge and low transmittance at 700 nm in the absorption behavior of Cu(II) ions.

[0083] The present invention also applies to filters. Filters according to the present invention include the filter glass according to the present invention described above. It is advantageous for the filter to have at least one coating on at least one side, for example, an organic layer, an interference layer system, a separate protective layer, or a combination thereof. In this case, it may be an anti-reflective (AR) and / or UV / IR cut coating. These layers reduce reflection and increase transmittance, or enhance IR blocking or UV blocking. Such layers may be designed in particular to block wavelengths below 430 nm or above 565 nm as intended. These layers are interference layers. In the case of an anti-reflective layer, it is applied to at least one side of the glass and consists of 4 to 10 layers of different and / or alternating compositions. In the case of a UV / IR cut coating, it may even be 50 to 70 layers of different and / or alternating compositions that form the UV / IR cut coating. These layers are preferably made of hard metal oxides, for example, SiO2, Ta2O3, TiO2, Al2O3, or metal oxynitrides. These layers are preferably applied to different sides of the filter glass. Furthermore, such coatings further enhance weather resistance / climate resistance. The filter glass according to the present invention has a longer filter life because its component Al2O3, sometimes combined with SiO2, enables better layer adhesion.

[0084] An important aspect of the present invention is the method for manufacturing glass according to the present invention. By carrying out the steps described below, the claimed glass can be obtained.

[0085] To produce the glass according to the present invention, a composite phosphate and / or metaphosphate is preferably added to the mixture as a raw material. The expression “composite phosphate” means that the phosphate is not added to the mixture in the form of “free” P2O5, but rather the glass components, such as Na2O, K2O, etc., are added to the mixture not in the form of oxides or carbonates, but as phosphates, such as Mg(H2PO4)2, LiH2PO4, KPO3, NaPO3. This means that the phosphate is added as the anionic component of the salt, and in this case, the corresponding cationic component of the salt itself is a component of the glass. Metaphosphates (e.g., Al(PO3)3) are polyphosphates, especially polyphosphates having a cyclic structure, which are advantageous because they bring more phosphate equivalents to the glass per cationic equivalent. This has the advantage of increasing the proportion of phosphates (compound phosphates, metaphosphates) in exchange for free P2O5, which can lead to improved internal quality, along with better controllability in melting behavior and a clear reduction in evaporation and dust accumulation. Furthermore, a higher proportion of free phosphates increases the requirements imposed on safety technology in the production plant, thereby increasing manufacturing costs. The means according to the present invention significantly improve the processability of the glass composition, and the mixture can be drier and better mixed. Furthermore, metering is more accurate than when using raw materials that absorb water from the surroundings during storage. Furthermore, for the deformation form of fluorine-containing glass, it can be advantageous to add fluorine in the form of fluoride-containing raw materials, especially together with cations of calcium, magnesium, barium, strontium, alkali metals, and aluminum.

[0086] Advantageously, only small amounts of glass components are added as oxides. Alkali oxides and alkaline earth oxides can also be introduced as carbonates.

[0087] According to the present invention, the raw materials for the glass are selected to obtain a mixture with the lowest possible melting point (the melting temperature is advantageously less than 1250°C, advantageously up to 1200°C, and up to 1150°C or 1100°C for some variants).

[0088] By adding nitrates to the mixture, oxidation conditions in the molten material can be established. Nitrates also act as a flux, contributing to a decrease in the melting temperature. For absorption in the IR range, the presence of +2 valent copper ions and, if present, +5 valent vanadium ions is important. Therefore, the glass is melted under oxidation conditions using a method known to the extent of the process. Instead of using nitrates, or in addition, oxygen bubbling can be performed in the molten material (see below).

[0089] The glass according to the present invention is melted at a temperature of 930 to 1250°C from a pre-mixed homogeneous mixture of a suitable composition, either in a discontinuous crucible, for example, in a Pt crucible, or in a continuous melting unit, such as an AZS (Al2O3-ZrO2-SiO2) bath, a Pt bath, or a quartz glass bath, and then clarified and homogenized. During the melting of the glass, components contained in the material of the crucible or bath may enter the glass. That is, after melting in a quartz glass bath, up to 2.0% by mass of SiO2 may be contained in the glass even if it has not been explicitly added. The melting temperature depends on the selected composition.

[0090] To adjust the oxidation-reduction ratio in the molten material, the glass can be advantageously bubbling with oxygen. The glass according to the present invention can be produced, in particular, by a method of performing oxygen bubbling in the molten material for 10 to 40 minutes, preferably 10 to 30 minutes, in the case of discontinuous melting, such as melting in a crucible. In the case of continuous melting, such as melting in a tank, bubbling can be advantageously performed continuously and advantageously in the melting region of the tank. In this case, the oxygen flow rate is advantageously at least 40 liters per hour, more preferably at least 50 l / h, even more advantageously up to 80 l / h, and even more preferably up to 70 l / h. Bubbling also helps to homogenize the molten material. In addition to the effects described above, it also promotes crosslinking in the glass.

[0091] Considering these parameters, if the composition range according to the present invention is maintained, glass according to the present invention can be obtained. The manufacturing method described herein, and the glass that can be manufactured therefrom, are also components of the present invention.

[0092] Glass clarification is advantageously carried out at temperatures ranging from 980 to a maximum of 1200°C. To minimize the evaporation of volatile components, such as Li2O and P2O5, the aforementioned temperatures should generally be kept low.

[0093] The use of the filter glass according to the present invention as a filter, particularly as an NIR cut filter, is also according to the present invention. Furthermore, the use of this glass to protect the CCD in a camera is also according to the present invention. Moreover, the filter glass according to the present invention can be used in fields such as safety, aviation, and night vision, within the scope of the present invention. [Brief explanation of the drawing]

[0094] [Figure 1] This figure shows the transmittance curve of the filter glass according to the present invention, along with the transmittance curve of a filter glass from the prior art. [Figure 2] This figure shows the transmittance curve of the filter glass according to the present invention. [Figure 3]This figure shows the transmittance curve of the filter glass according to the present invention. [Figure 4] This figure shows the transmittance curve of the filter glass according to the present invention. [Figure 5] This figure shows the transmittance curve of the filter glass according to the present invention. [Examples]

[0095] To produce filter glass having a composition corresponding to the example, the appropriate glass mixture is vigorously mixed. This mixture is melted at 1200°C for about 3 hours and bubbling with oxygen for about 30 minutes. Based on the low viscosity, clarification is also carried out at 1100-1150°C. After standing for about 15-30 minutes, casting is performed at a temperature of about 950°C.

[0096] This glass has a Knoop hardness of approximately 400-450 HK, and in further deformation forms, it can even reach higher values ​​of up to approximately 475, thus possessing good workability and sufficient scratch resistance. The coefficient of thermal expansion measured over a temperature range of 20-300°C is 9.5 × 10⁻⁶. -6 / K~<13×10 -6 The glass transition temperature of the glass is T. g The temperature range is 350-450°C.

[0097] Spectral characteristics were evaluated using spectrophotometers (Perkin-Elmer Lambda 900 and 950). Polished glass samples with thicknesses ranging from 0.205 mm to 0.6 mm were prepared and their transmittance was measured. Where necessary, the transmittance for a reference thickness of 0.205 mm was calculated and recorded in Tables 1-5 for this reference thickness.

[0098] Table 1 shows the results for Examples (Examples 1-15) and Comparative Example (Example 16) for a reference thickness of 0.205 mm. The Examples showed an average transmittance (T) exceeding 83% in the range of 430-565 nm. avg This shows the transmittance at 700 nm (T), which is a measure of blocking in the NIR range. 700) is up to 12% in many examples. The examples shown exhibit high transmittance in the transmission range and blockage in the NIR range, but certain T 50 The values ​​have not yet been optimized.

[0099] Table 2 shows filter glasses with compositions optimized for the steep transition of the NIR edge of the transmittance curve for a standard thickness of 0.205 mm. The composition is such that the filter glass meets the specification requirement of "626 nm T 50 The values ​​were adjusted to satisfy the specified value. Examples 17-31 are examples, and Example 32 is a comparative example. The examples showed an average transmittance (T) greater than 83% in the range of 430-565 nm. avg ) shows. Except for example 30, at least 86% of T avg Even this is achieved. Transmittance at 700nm (T 700 The percentage was up to 12% in all examples and less than 11% in many examples.

[0100] Table 3 shows further examples (Examples 33-40) of filter glass having compositions optimized for the steep transition of the NIR edge of the transmittance curve relative to a reference thickness of 0.205 mm. The examples show an average transmittance (T) exceeding 86% in the range of 430-565 nm. avg ) is shown. Transmittance at 700nm (T 700 The percentage was less than 12% in all examples. Further physical properties of these glasses were identified.

[0101] Table 5 shows further examples (Examples 43-53) of filter glass having compositions optimized for the steep transition of the NIR edge of the transmittance curve relative to a reference thickness of 0.205 mm. The examples show an average transmittance (T) exceeding 83% in the range of 430-565 nm. avg ) is shown. Transmittance at 700nm (T 700 The percentage was less than 12% in all examples. Further physical properties were identified for some of these glasses.

[0102] Therefore, the examples in Tables 2, 3, and 5 are T 50The filter glass exhibits high transmittance in the transmission range and high blocking in the NIR range at a value of 626 nm, resulting in a steep transition at the NIR edge, as can be seen in Figures 1-5. For comparison, Figure 1 shows the transmittance curve of a filter glass from the prior art. Known filter glasses have a reference thickness of 0.205 mm and T 50 At a value of 626 nm, it has a significantly lower transmittance in the transmission range than the filter glass according to the present invention shown, and a lower T in the range of 430 to 565 nm. avg It also possesses.

[0103] Table 4 shows the results for the examples (Examples 41-42) for a reference thickness of 0.205 mm. The examples showed an average transmittance (T) exceeding 83% in the range of 430-565 nm. avg This shows the transmittance at 700 nm (T), which is a measure of blocking in the NIR range. 700 ) is up to 15% in many examples. The examples shown exhibit high transmittance in the transmission range and blockage in the NIR range, but certain T 50 The values ​​have not yet been optimized.

[0104] Those skilled in the art will know the target thickness and / or T 50 We are well-versed in how to adapt the copper content in the base glass when other requirements are imposed on the filter glass in terms of values.

[0105] [Table 6-1]

[0106] [Table 6-2]

[0107] [Table 7-1]

[0108] Table 7-2

[0109] Table 8

[0110] Table 9

[0111] Table 10-1

[0112] Table 10-2

Claims

1. 1. Li (more than 1.1 mass% to 6.0 mass%) 2 O and Na 2 O and K 2 It contains at least one further component selected from O, and has the following composition (mass %) based on oxides: P 2 O 5 55.0~75.0 Al 2 O 3 4.1-8.0 CuO 8.0~18.0 V 2 O 5 0 to less than 0.8 SiO 2 2.0 or less F2.0 or less Total of R'O (R' = Mg, Ca, Sr, Ba, Zn) 0 to 11.0 R 2 Total O (R = Li, Na, K) 3.0 to 17.0 A filter glass having [a certain feature].

2. The aforementioned filter glass contains at least 0.3% by mass of Na 2 O and K 2 It contains at least one further component selected from O, and / or the filter glass is Li 2 O and Na 2 O and K 2 A filter glass according to claim 1, comprising O.

3. The filter glass according to claim 1, wherein the total amount of R'O is a maximum of 10.5% by mass, and / or the filter glass contains a maximum of two components selected from the group R'O, and / or the filter glass contains only one component selected from the group R'O.

4. The CuO content is a maximum of 17.0% by mass, preferably a maximum of 16.0% by mass, and / or at least 8.5% by mass, and / or V 2 O 5 The filter glass according to claim 1, wherein it contains up to 0.6% by mass or up to 0.5% by mass.

5. The aforementioned filter glass is La 2 O 3 It contains a maximum of 4.0% by mass, preferably a maximum of 3.5% by mass, and / or Y 2 O 3 The filter glass according to claim 1, containing at a maximum of 4.0% by mass, preferably at a maximum of 3.5% by mass.

6. The aforementioned glass is B 2 O 3 , ZrO 2 Nb 2 O 5 Yb 2 O 3 , Gd 2 O 3 WO 3 Fe 2 O 3 The filter glass according to claim 1, which is free of PbO and / or CoO, and / or other coloring components, such as Cr, Mn and / or Ni, and / or optically active components, such as laser active components, such as Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er and / or Tm.

7. The aforementioned filter glass has an average transmittance T in the range of 430 to 565 nm relative to a reference thickness of 0.205 mm. ａｖｇ The filter glass according to claim 1, having at least 83%, preferably at least 85%, preferably at least 86% or at least 87%, and / or the filter glass having a transmittance of up to 12%, preferably up to 11.5%, and preferably up to 11% at 700 nm with respect to a reference thickness of 0.205 mm.

8. The T of the glass at a standard thickness of 0.205 mm ５０ The filter glass according to claim 1, wherein the value is in the range of 610 nm to 640 nm, preferably in the range of 618 nm to 634 nm, preferably in the range of 620 nm to 632 nm, and preferably in the range of 622 nm to 630 nm.

9. Thermal expansion coefficient (α 20-300 ) up to 13 x 10 -6 / K, more preferably up to 12.5 × 10 -6 / K, particularly preferably a maximum of 12 x 10 per 1K -6 , and / or at least 9.5 × 10 -6 / K, to be favorable, at least 9.8 x 10 -6 / K, to be favorable, at least 10 x 10 -6 The filter glass according to claim 1, wherein the temperature is / K and / or the transition temperature is greater than 350°C.

10. A filter comprising the filter glass described in any one of claims 1 to 9.

11. The filter according to claim 10, wherein the filter glass has at least one coating on at least one of its surfaces.

12. A method for manufacturing a filter glass according to any one of claims 1 to 9, comprising the following steps: - Adding at least one glass component, preferably multiple glass components, as a composite phosphate and / or metaphosphate. - A step in which a molten glass component is produced, wherein the melting temperature does not exceed 1250°C. - Adding nitrates and / or bubbling the glass molten material with oxygen. The method comprising the above.

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