Near-infrared absorbing glass and near-infrared cut filters

Abstract

To provide a near-infrared absorbing glass that offers high visible light transmittance despite reduced thickness, exhibits excellent near-infrared blocking ability, and can suppress deterioration in weather resistance.SOLUTION: The present invention provides a glass comprising P ions, Li ions, and Cu ions as essential cations and comprising at least O ions as anions, wherein the ratio of the content of O ions to the content of P ions is 3.15 or less, the content of O ions is 90.0 anion% or more in the glass composition in terms of anion%, the total content of oxides of major cations is 90.0% or more, the total content of MgO and Al2O3 is 8.0% or less, the ratio of the total content of Na2O, K2O, and ZnO to the content of Li2O is 2.4 or less, the total content of B2O3 and SiO2 is 3.0% or less, and the CuO content is α1% or more, where α1 is a value calculated by formula 1 (R is the ratio of O ions to P ions): (Formula 1) α1=70400×exp(-2.855×R).SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to near-infrared absorbing glass and near-infrared cut filters. [Background technology]

[0002] In recent years, small cameras, such as those found in smartphones, not only is the acquired image information simply digitized, but the image is also reconstructed by performing various computer processing operations on that image information. For example, it has become common practice to extract a specific object and adjust the color and contrast of the image. In this process, if color information that does not originally exist is input to the image sensor due to light reflection in the optical element, that information must be removed, which is undesirable.

[0003] A near-infrared cut filter has the function of cutting out unwanted near-infrared light (wavelength 700-1200 nm) within the sensitivity wavelength range of the image sensor. Near-infrared cut filters are generally installed directly in front of the image sensor.

[0004] Near-infrared cut filters widely used are those made from near-infrared absorbing glass, which is polished onto a flat plate.

[0005] Near-infrared absorbing glass generally contains Cu ions. An example of the spectral transmission characteristics of near-infrared absorbing glass is shown in Figure 1. Note that Figure 1 does not limit the present invention in any way. The light absorption characteristics around wavelengths of 700 to 1200 nm are due to the Cu ions in the glass (Cu 2+ It is expressed by ). In particular, glass containing P ions along with Cu ions is expressed by Cu ions (Cu 2+ Because it can exhibit near-infrared absorption characteristics over a wide wavelength range, it is useful as glass for near-infrared cut filters (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2014-12630

[0007] In the transmittance curve for wavelengths above 600 nm shown in Figure 1, the wavelength at which the transmittance is 50% is called the "half-value" and is one of the main specifications for near-infrared cut filters. The half-value varies depending on the filter specifications, but it is often set in the wavelength range of 600 nm to 650 nm. A common method for setting the half-value to the desired value is to adjust the thickness of the glass substrate or the Cu ions in the glass, following the Lambert-Beer law. 2+ There are ways to adjust either the concentration or the concentration. [Overview of the project] [Problems that the invention aims to solve]

[0008] Near-infrared cut filters are required to have excellent ability to cut near-infrared light (i.e., have a desired half-value while having low transmittance of near-infrared light), as well as high transmittance in the visible range (purple to red regions).

[0009] Furthermore, in recent years, image sensor modules used in smartphones and other devices are required to be both miniaturized and high-performance, and the thickness of near-infrared cut filters is required to be thinner. As a result, the thickness of near-infrared absorbing glass has been reduced from the conventional 1 mm to around 0.45 mm, 0.3 mm, or 0.2 mm in recent years, and there is even a desire to reduce it to as thin as 0.1 mm.

[0010] Simply thinning near-infrared absorbing glass reduces the optical concentration of CuO (moles × thickness) required for near-infrared absorption, thus decreasing the near-infrared absorption efficiency. One possible solution is to increase the amount of CuO. However, simply increasing the amount of CuO causes CuO absorption to reach the visible region (i.e., the red region) around 600 nm, and also tends to decrease transmittance on the shorter wavelength side. Therefore, it is difficult to maintain both transmittance in the visible region (purple to red region) and near-infrared absorption.

[0011] Furthermore, in order to provide a near-infrared absorbing glass suitable for use in high-temperature and high-humidity environments, it is desirable that the deterioration of weather resistance in such environments be suppressed. However, according to the inventors' research, it is not easy to suppress the deterioration of weather resistance while maintaining both the transmittance in the visible range (purple to red regions) and the absorption of near-infrared rays.

[0012] In view of the above, one aspect of the present invention aims to provide a near-infrared absorbing glass that has high transmittance in the visible region (purple region to red region) even when thinned, has excellent near-infrared cutting ability, and can suppress a decrease in weather resistance, and a near-infrared cut filter made of such near-infrared absorbing glass. [Means for solving the problem]

[0013] One aspect of the present invention is, It contains four or more major cations selected from the group consisting of P ions, Li ions, Cu ions, Al ions, Ba ions, Sr ions, Ca ions, Mg ions, Zn ions, K ions, Na ions, La ions, Gd ions, and Y ions. It contains P ions, Li ions, and Cu ions as essential cations. It contains at least an O ion as an anion, The ratio of O ions to P ions (O ions / P ions) is 3.15 or less. In the glass composition expressed in anion percentage, the O ion content is 90.0 anion% or more. In oxide-based glass composition, In terms of moles, The total content of oxides of the above major cations is 90.0% or more. The total content of MgO and Al2O3 (MgO + Al2O3) is 8.0% or less. The ratio of the total content of Na2O, K2O, and ZnO to the Li2O content ((Na2O+K2O+ZnO) / Li2O) is 2.4 or less. The total content of B2O3 and SiO2 (B2O3 + SiO2) is 3.0% or less. The CuO content is α1% or more. α1 is given by the following equation 1: (Formula 1) α1 = 70400 × exp(-2.855 × R) This is a value calculated by, In formula 1 above, R is the above ratio (O ions / P ions). Near-infrared absorbing glass (hereinafter also referred to as "glass 1"), Regarding.

[0014] Furthermore, one embodiment of the present invention is: It contains four or more major cations selected from the group consisting of P ions, Li ions, Cu ions, Al ions, Ba ions, Sr ions, Ca ions, Mg ions, Zn ions, K ions, Na ions, La ions, Gd ions, and Y ions. It contains P ions, Li ions, and Cu ions as essential cations. It contains at least an O ion as an anion, The ratio of O ions to P ions (O ions / P ions) is 3.15 or less. In the glass composition expressed in anion percentage, the O ion content is 90.0 anion% or more. In oxide-based glass composition, In terms of moles, The total content of oxides of the above major cations is 90.0% or more. The total content of MgO and Al2O3 (MgO + Al2O3) is 8.0% or less. The ratio of the total content of Na2O, K2O, and ZnO to the Li2O content ((Na2O+K2O+ZnO) / Li2O) is 2.4 or less. The total content of B2O3 and SiO2 (B2O3 + SiO2) is 3.0% or less. Formula 2 below: (Formula 2) C-3200×exp(-2.278×R)≧0 Satisfying the conditions, In equation 2 above, C represents the CuO content per molar volume of glass (unit: millimoles / cc), R is the above ratio (O ions / P ions). Near-infrared absorbing glass (hereinafter also referred to as "glass 2"), Regarding.

[0015] Furthermore, one embodiment of the present invention is: It contains four or more major cations selected from the group consisting of P ions, Li ions, Cu ions, Al ions, Ba ions, Sr ions, Ca ions, Mg ions, Zn ions, K ions, Na ions, La ions, Gd ions, Y ions, B ions, and Si ions. It contains P ions, Li ions, and Cu ions as essential cations. It contains at least an O ion as an anion, The ratio of O ions to P ions (O ions / P ions) is 3.15 or less. In the glass composition expressed in anion percentage, the O ion content is 90.0 anion% or more. In oxide-based glass composition, In terms of moles, The total content of oxides of the above major cations is 90.0% or more. The total content of MgO and Al2O3 (MgO + Al2O3) is 8.0% or less. The ratio of the total content of Na2O, K2O, and ZnO to the Li2O content ((Na2O+K2O+ZnO) / Li2O) is 2.4 or less. Formula 3 below: (Formula 3) A1 = {O(P) - O(others)} × Cu The A calculated by is 2500 or more, In the above formula 3, O(P) indicates the amount of oxygen constituting the oxide of P ions in the oxide-based glass composition. O(others) represents the amount of oxygen obtained by subtracting the above O(P) from the amount of oxygen constituting the oxide of the above major cation in the oxide-based glass composition. Cu represents the molar CuO content in the oxide-based glass composition, and is used in near-infrared absorbing glass (hereinafter also referred to as "glass 3"). Regarding.

[0016] Furthermore, one embodiment of the present invention is: It contains four or more major cations selected from the group consisting of P ions, Li ions, Cu ions, Al ions, Ba ions, Sr ions, Ca ions, Mg ions, Zn ions, K ions, Na ions, La ions, Gd ions, Y ions, B ions, and Si ions. It contains P ions, Li ions, and Cu ions as essential cations. It contains at least an O ion as an anion, The ratio of O ions to P ions (O ions / P ions) is 3.15 or less. In the glass composition expressed in anion percentage, the O ion content is 90.0 anion% or more. In oxide-based glass composition, In terms of moles, The total content of oxides of the above major cations is 90.0% or more. The total content of MgO and Al2O3 (MgO + Al2O3) is 8.0% or less. The ratio of the total content of Na2O, K2O, and ZnO to the Li2O content ((Na2O+K2O+ZnO) / Li2O) is 2.4 or less. Formula 4 below: (Formula 4) A2 = {O(P) - O(others)} × C The A2 calculated by this method is 700 or more. In equation 4 above, C represents the CuO content per molar volume of glass (unit: millimoles / cc), O(P) indicates the amount of oxygen constituting the oxide of P ions in the oxide-based glass composition. O(others) represents the amount of oxygen obtained by subtracting O(P) from the amount of oxygen constituting the oxide of the above-mentioned major cation in the oxide-based glass composition, and is a near-infrared absorbing glass. (Hereinafter also referred to as "glass 4.") Regarding.

[0017] One aspect of the present invention is, It contains four or more major cations selected from the group consisting of P ions, Li ions, Cu ions, Al ions, Ba ions, Sr ions, Ca ions, Mg ions, Zn ions, K ions, Na ions, La ions, Gd ions, and Y ions. It contains P ions, Li ions, and Cu ions as essential cations. It contains at least an O ion as an anion, The ratio of O ions to P ions (O ions / P ions) is 3.15 or less. In the glass composition expressed in anion percentage, the O ion content is 90.0 anion% or more. In oxide-based glass composition, In terms of moles, The total content of oxides of the above major cations is 90.0% or more. The total content of MgO and Al2O3 (MgO + Al2O3) is 8.0% or less. The ratio of the total content of Na2O, K2O, and ZnO to the Li2O content ((Na2O+K2O+ZnO) / Li2O) is 2.4 or less. The CuO content is α2% or more. α2 is given by the following equation 5: (Formula 5) α² = (76522) × exp(-2.855 × R) This is a value calculated by, In the above formula 5, R is the above ratio (O ions / P ions). Near-infrared absorbing glass (hereinafter also referred to as "glass 5"), Regarding.

[0018] Furthermore, one embodiment of the present invention is: It contains four or more major cations selected from the group consisting of P ions, Li ions, Cu ions, Al ions, Ba ions, Sr ions, Ca ions, Mg ions, Zn ions, K ions, Na ions, La ions, Gd ions, and Y ions. It contains P ions, Li ions, and Cu ions as essential cations. It contains at least an O ion as an anion, The ratio of O ions to P ions (O ions / P ions) is 3.15 or less. In the glass composition expressed in anion percentage, the O ion content is 90.0 anion% or more. In oxide-based glass composition, In terms of moles, The total content of oxides of the above major cations is 90.0% or more. The total content of MgO and Al2O3 (MgO + Al2O3) is 8.0% or less. The ratio of the total content of Na2O, K2O, and ZnO to the Li2O content ((Na2O+K2O+ZnO) / Li2O) is 2.4 or less. Formula 6 below: (Formula 6) C - (3478) × exp(-2.278 × R) ≥ 0 Satisfying the conditions, In formula 6 above, C represents the CuO content per molar volume of glass (unit: millimoles / cc), R is the above ratio (O ions / P ions). Near-infrared absorbing glass (hereinafter also referred to as "glass 6"), Regarding. [Effects of the Invention]

[0019] According to one aspect of the present invention, it is possible to provide near-infrared absorbing glass that exhibits high transmittance in the visible region (purple to red region) even when thinned, has excellent near-infrared cutting ability, and can suppress the deterioration of weather resistance. Furthermore, according to one aspect of the present invention, it is possible to provide a near-infrared cut filter made of such near-infrared absorbing glass. [Brief explanation of the drawing]

[0020] [Figure 1] An example of the spectral transmission characteristics of near-infrared absorbing glass is shown. [Modes for carrying out the invention]

[0021] [Near-infrared absorbing glass] In the following, Glass 1-6 will be collectively referred to simply as "glass" or "near-infrared absorbing glass." Unless otherwise specified, the descriptions of glass composition and physical properties apply to all of Glass 1-6.

[0022] In the present invention and this specification, near-infrared absorbing glass is glass that has the property of absorbing light of all or part of the wavelength range of at least the near-infrared wavelength range (wavelength 700 to 1200 nm). Furthermore, since the near-infrared absorbing glass according to one aspect of the present invention contains O ions as constituent ions, it can be oxide glass. Oxide glass is glass in which the main network-forming component of the glass is an oxide. Moreover, since the near-infrared absorbing glass according to one aspect of the present invention contains P ions (cations) along with O ions (anions) as constituent ions, it can be phosphate glass. Note that the O ion is an anion of the oxygen atom and is generally also called an oxide ion.

[0023] The following provides a more detailed explanation of glass types 1 through 6.

[0024] <Glass composition> (Analysis method) The various components that make up glass can be quantified using known methods, such as inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS), to determine the elemental content (elemental mass %) contained in the glass. For anion components, the anion components contained in glass can be identified and quantified by known analysis methods, for example, ion chromatography, non-dispersive infrared absorption method (ND-IR), and the like. In the present invention and the present specification, the expressions that the content of a component is 0%, or the component is not contained, or the component is not introduced mean that the component is not substantially contained, and it is allowable that the component is contained at an unavoidable impurity level.

[0025] (Description of Glass Composition on Oxide Basis) Based on the results obtained from the above analysis, the content (unit: mol%) of each component in the glass composition on an oxide basis can be calculated. The specific method is as follows. The content of element i obtained by the above analysis method (mass% P of the element i ) is divided by the atomic weight M of element i i to obtain the number of moles n of each element i = P i / M i . When the element i is a cationic component A i , the number of moles n of the element obtained above i is converted to the number of moles n' of the corresponding oxide i . Specifically, when the composition formula of the oxide of the cationic component A i corresponding to element i is represented by A i xOy, n' i = n i / x. When the element i is an anionic component B other than O ion i , the corresponding number of moles n of the above element i is hereinafter denoted as m i . In the glass composition on an oxide basis, the content P_A i as the oxide A i xOy of the cationic component A i (mol%) is P_A i = n' i / (Σn' i +Σm i )×100 It is expressed as follows. The content in the oxide-based glass composition can also be called the oxide-based fraction.

[0026] In the oxide-based glass composition, anionic component B other than O ions. i Oxide-based fraction PB i (mol %) is PB i =m i / (Σn' i +Σm i ) × 100 It is represented as follows.

[0027] Here, Σn' i This is oxide A of the cationic components contained in glass. i This is the total number of moles of xOy. However, depending on the significant figures of the content, ignoring trace components will not affect the calculation result.

[0028] (Anion%) "Anion %" is a value calculated as "(the amount of anion i of interest expressed in mole percentage) / (the total number of anions expressed in mole percentage in the glass) × 100", and represents the mole percentage of the amount of anion of interest relative to the total amount of anions. Based on the above explanation of the notation of glass composition based on oxides, the anion percentage of O ions is: Cation component A corresponding to element i i The chemical formula of the oxide is A i Represented as xOy, with cation component A i The number of oxygen atoms contained in the oxide is the cation component A i Oxide-based fraction PA i (using mole%) i =PA i ×y, anionic component B k The valence of N k When (ΣO i -Σ(N k / 2)B k ) / (ΣO i -Σ(N k / 2)B k +ΣB k ) × 100 It can be calculated as follows. Here ΣO i Σ(N) is the sum of the moles of O ions in the oxide-based glass composition. k / 2)B k is anion component B k This represents the number of moles of O ions substituted by (ΣO). i -Σ(N k / 2)B k This represents the number of moles of oxygen ions contained in the glass. On the other hand, in the present invention and this specification, regarding the oxygen content, if no anionic components other than oxygen are detected by analysis using known methods, it is assumed that all of the anionic components (i.e., 100% anions) are O ions.

[0029] (Cationic component) For the valency of the cationic components, the formal valency of each cation is used. The formal valency is the valency required for the oxide of the cation of interest to maintain electrical neutrality when the valency of the O ion constituting the oxide is -2, and it can be uniquely determined from the chemical formula of the oxide. For example, regarding the Cu ion, the O contained in the chemical formula of the oxide CuO is 2- To maintain electrical neutrality with Cu, the valence of Cu becomes +2. Also, for example, the P ion is included in the chemical formula of the oxide P2O5. 2- To maintain electrical neutrality with P, the valency of P is +2 × 5 / 2 = +5. Generalizing this, the formal valency of the cation Ai contained in the oxide AixOy is "+2y / x". Therefore, when analyzing the glass composition, it is not necessary to analyze the valency of the cation. Furthermore, the valency of anions (for example, the valency of the O ion is -2) is a formal valency based on the idea that the O ion accepts two electrons and takes on a closed-shell structure. Therefore, when analyzing the glass composition, it is not necessary to analyze the valency of anions. Also, Cu 2+ A portion of it is Cu when it melts. + This is possible, but usually the amount is so small that it is acceptable to consider the valency of all Cu as +2.

[0030] (Anionic component) The above glass contains at least O ions as anions, and its content is 90.0% or more in the glass composition expressed as anion percent. The inventors believe that by lowering the O / P ratio in glass mainly composed of O ions as anions, the absorption of CuO in the red region can be shifted to the longer wavelength side, thereby increasing the CuO content without reducing the transmittance in the red region and improving the near-infrared cutting ability. The O ion content in the glass composition expressed as anion percent is 90.0% or more, preferably 95.0% or more, more preferably 98.0% or more, and even more preferably 99.0% or more. A high proportion of O ions in the anion component is also preferable in suppressing volatilization during glass melting. Suppressing volatilization during glass melting is preferable from the viewpoint of suppressing the occurrence of striations. In particular, from the viewpoint of suppressing volatilization during glass melting, increasing productivity, and suppressing the generation of harmful gases during manufacturing, it is preferable that the O ion content be 100%. The formal valency of the O ion is -2.

[0031] The above glass can contain only the O ion in one form, and in another form, it can contain one or more other anions along with the O ion. Examples of other anions include the F ion, Cl ion, Br ion, and I ion. The formal valency of the F ion, Cl ion, Br ion, and I ion is -1.

[0032] From the viewpoint of improving the homogeneity and strength of the glass, the F ion content is preferably 15.0 anion% or less, more preferably 10.0 anion% or less, even more preferably 5.0 anion% or less, even more preferably 2.0 anion% or less, and even more preferably 1.0 anion% or less. In particular, from the viewpoint of suppressing volatilization during glass melting, increasing productivity, and suppressing the generation of harmful gases during manufacturing, the above glass may also be glass that does not contain F ions.

[0033] (O / P ratio) The molar ratio of cation content to anion content is the ratio (in mole percent) of the content of the component of interest when the total amount of all cationic and anionic components is set to 100 mol%. Therefore, the ratio of O ions to P ions (O ions / P ions) is the ratio (in mole percent) of O ions to the P ion content (in mole percent) when the total amount of all cationic and anionic components is set to 100 mol%.

[0034] Method 1 for calculating the O / P ratio Regarding the O / P ratio (also denoted as R), the O / P ratio based on the explanation of the notation for the oxide-based glass composition described above is: Cation component A corresponding to element i i The chemical formula of the oxide is A i Represented as xOy, the number of oxygen atoms in the oxide of the cation component Ai is expressed using the oxide-based fraction PAi (mol%) of the cation component Ai. i =PA i ×y, anionic component B k The valence of N k When Formula D1: R1=ΣO i -Σ(N k / 2)B k Equation D2: R2 = Percentage of oxides of P ions (i.e., P2O5) (mol%) × 2 The O / P ratio (R) is Formula D3: R=R1 / R2 It can be calculated from this. For example, taking Comparative Example A, described later, as an example, the content of oxides in the glass composition of Comparative Example A, expressed in mole percent, is P2O5 = 53.59, Li2O = 19.30, and CuO = 27.11. The number of oxygen atoms in the molecular formula is 5 for P2O5, 1 for Li2O, and 1 for CuO. The number of moles of oxygen atoms in the molecular formula is 267.95 for P2O5, 19.30 for Li2O, and 27.11 for CuO. The O / P ratio of the glass in this example can be determined as follows. Molecular formula of glass: 53.59P2O5-19.30Li2O-27.11Number of O ions in CuO: N S To determine this, we need to determine the molecular formula of glass, which is the compositional formula of glass such that the total number of molecules contained in the glass equals 100. That is, using the number of O ions contained in the molecular formula MxOy of each oxide (P2O5: 5, Li2O: 1, CuO: 1), N S = 53.59 × 5 + 19.30 × 1 + 27.11 × 2 = 314.36 as N S Calculate. In the example above, the glass has zero O ions substituted by other anions in its molecular formula, therefore this N S By dividing = 314.36 by the number of moles of P contained in P2O5, which is 53.59 × 2, we can obtain the O / P ratio = 314.36 / (53.59 × 2) = 2.93...

[0035] Method 2 for Calculating the O / P Ratio If analysis by known methods detects one or more anionic components in addition to oxygen, the oxygen content can be determined by the following method (3) (unit: anion %), calculated from (1) the cation content based on the valence and elemental mole percent of the cation components contained in the glass and (2) the anion content based on the valence and elemental mole percent of the anionic components other than oxygen. In other words, based on the results of identification and quantitative analysis using known methods, (1) For the cationic components contained in the glass, calculate the total U based on "the number of oxygen atoms per cation y / x × the mole percentage of the element, which consists of the number of oxygen atoms y and the number of cations x in the oxide MxOy". (2) For anionic components other than oxygen, the total V is calculated from the results of identification and quantitative analysis by known methods and the valence z of the anion, which is "anion content based on the mole percent of the element × the number of oxygen atoms substituted per anion z / 2". (3) UV can also be used as the ratio of O ions to P ions.

[0036] As examples of calculation method 2, calculation example 1 and calculation example 2 are shown below.

[0037] Calculation Example 1: When the molar percentages of P ions, Li ions, and Cu ions are quantified as 22.0, 8.0, and 5.5 (elemental content expressed in molar percentage), the y / x values ​​for the corresponding oxides P2O5, Li2O, and CuO are 2.5, 0.5, and 1.0, respectively. U = 22 × 2.5 + 8 × 0.5 + 5.5 × 1.0 = 64.5, V = 0. Therefore, the molar percentage of O ions, based on the molar percentage of the element, is 64.5 (the content expressed as molar percentage of the element). From the ratio of the O ion value obtained in this way and the molar percentage of the analyzed P ions, the O / P ratio can be calculated as 64.5 / 22 = 2.93...

[0038] Calculation Example 2: When the molar percentages of P ions, Li ions, and Cu ions are 22.0, 8.0, and 5.5 (elemental content expressed in molar percentage), and the molar percentage of F ions is 4.0 (elemental content expressed in molar percentage), the y / x values ​​for the corresponding oxides P2O5, Li2O, and CuO are 2.5, 0.5, and 1.0, respectively, and the valence of F is -1, U = 22 × 2.5 + 8 × 0.5 + 5.5 × 1.0 = 64.5, V = 4 × 1 / 2 = 2. Therefore, the molar percentage of O ions, based on the molar percentage of the element, is 62.5 (the content expressed as molar percentage of the element). From the O ion value obtained in this way and the ratio of the molar percentage of P ions analyzed, the O / P ratio can be calculated as 62.5 / 22 = 2.84...

[0039] In glass 1 to 6, the ratio of O ions to P ions (O / P ratio) is 3.15 or less, from the viewpoint of achieving both improved visible light transmittance and improved near-infrared cut capability, as well as from the viewpoint of improving the thermal stability of the glass. In glass 1 to glass 6, the O / P ratio is preferably 3.14 or less, and is more preferably 3.13 or less, 3.12 or less, 3.11 or less, 3.10 or less, 3.09 or less, 3.08 or less, 3.07 or less, 3.06 or less, 3.05 or less, 3.04 or less, 3.03 or less, 3.02 or less, 3.01 or less, and 3.00 or less, in that order. On the other hand, from the viewpoint of improving weather resistance and / or suppressing a decrease in meltability, it is preferable that the O / P ratio is high in Glass 1 to Glass 6. From this point of view, it is preferable that the O / P ratio in Glass 1 to Glass 6 be 2.50 or higher, and in order of preference, it is preferable that it be 2.60 or higher, 2.65 or higher, 2.70 or higher, 2.73 or higher, 2.75 or higher, 2.77 or higher, 2.80 or higher, 2.81 or higher, 2.82 or higher, 2.83, 2.84 or higher, 2.85 or higher, 2.86 or higher, 2.87 or higher, 2.88 or higher, 2.89 or higher, and 2.90 or higher.

[0040] (Cationic component) Glasses 1-6 contain four or more major cations selected from the group consisting of P ions, Li ions, Cu ions, Al ions, Ba ions, Sr ions, Ca ions, Mg ions, Zn ions, K ions, Na ions, La ions, Gd ions, and Y ions, and contain P ions, Li ions, and Cu ions as essential cations. In the oxide-based glass composition (molar basis) of glasses 1-6, the total content of oxides of the above major cations is 90.0% or more. In glasses 1 to 6, having a total content of oxides of major cations of 90.0% or more can contribute to improving the thermal stability of the glass and / or to improving the optical homogeneity of the glass by suppressing striations and volatilization. From the above standpoint, the total content of oxides of the major cations in glasses 1 to 6 is preferably 92.0% or more, more preferably 93.0% or more, 95.1% or more, 96.1% or more, 97.1% or more, 98.1% or more, 98.6% or more, 99.1% or more, and 99.6% or more, in that order, and can also be 100%. In one embodiment, the total content of oxides of the major cations in glasses 1 to 6 can be 100% or less, or 99.5% or less, 99% or less, 98.5% or less, 98.0% or less, and 97.5% or less.

[0041] The following explanation of the cationic component content will be given in terms of content based on the oxide-based glass composition (molar basis).

[0042] Since CuO is an essential component for giving glass the ability to cut near-infrared rays, glasses 1-6 contain Cu ions as essential cations.

[0043] In glass 1, the CuO content is α1% or more. α1 is a value calculated by the following formula 1.

[0044] (Formula 1) α1 = 70400 × exp(-2.855 × R)

[0045] In Equation 1, R is the O / P ratio.

[0046] Furthermore, for glass 2, the lower limit of the CuO content is determined by the CuO content per molar volume of the glass, as shown in equation 2 below.

[0047] (Formula 2) C-3200×exp(-2.278×R)≧0

[0048] In Formula 2, C is the CuO content per molar volume of glass (unit: mmol / cc), and R is the O / P ratio.

[0049] In Formula 2, C is obtained by the following method. C is determined by: measuring the specific gravity D (g / cc) of glass; determining the mass per 1 mole of glass composition, that is, the molar molecular weight M (g / mol), based on the glass composition obtained by analysis as described above; and determining the molar volume M / D (unit: cc / mol) of glass, C=mol% of CuO / (M / D)×1000 (unit: mmol / cc) can be calculated as. The molar molecular weight M is Based on the above description of the expression of glass composition on an oxide basis, the formula weight M_A of the corresponding oxide of the cationic component A_i i , the atomic weight of the anionic component B k is M_B k and the atomic weight of oxygen is M_o, then M={Σ(P_A i ×M_A i )+Σ(P_B k ×M_B k )-Σ(N k / 2)M_o} / ΣP_A i can be obtained as. For example, if the glass composition is composed of s mol% of A_2O component on an oxide basis, t mol% of BO component on an oxide basis, and u mol% of F component, wherein s+t+u=100 (%), the formula weight of the A_2O component is M A (g / mol), the formula weight of the BO component is M B (g / mol), the atomic weight of F is M F (g / mol), and the atomic weight of oxygen is M O (g / mol), then M=(s×M A +t×M B +u×M F -u / 2×M O ) / (s+t) is obtained. For example, the molar molecular weight M of Comparative Example A described later (the content in molar percent in the oxide-based glass composition is P2O5=53.59, Li2O=19.30, CuO=27.11) is, Molecular weight of P2O5: 141.94 (g / mol) Molecular weight of Li2O: 29.88 (g / mol) Molecular weight of CuO: 79.55 (g / mol) Using this, we can calculate M = (53.59 × 141.94 + 19.30 × 29.88 + 27·11 × 79.55) / (53.59 + 19.30 + 27.11) = 103.40 (g / mol).

[0050] As a result of diligent research, the inventors have newly discovered that in a glass mainly composed of O ions as an anion, reducing the O / P ratio shifts the absorption of CuO in the red region to the longer wavelength side, thereby suppressing a decrease in transmittance in the red region while increasing the CuO content. Furthermore, the inventors have newly discovered a good correlation between the O / P ratio and the CuO content required to achieve a predetermined half-value at a predetermined wall thickness. As a result, the inventors have determined the lower limits (α1, α2) of the CuO content for glass 1, where the O / P ratio is within the range described above, using Equation 1, and for glass 5, using Equation 5. In addition, the inventors have determined the CuO content per molar volume of glass using Equation 2, where the O / P ratio is within the range described above, and for glass 6, using Equation 6.

[0051] In glass 3, the CuO content is determined based on A1 calculated by the following formula 3, where A1 is 2500 or more.

[0052] (Formula 3) A1 = {O(P) - O(others)} × Cu

[0053] In Equation 3, O(P) represents the amount of oxygen constituting the oxide of the P ion in the oxide-based glass composition, O(others) represents the amount of oxygen obtained by subtracting the above O(P) from the amount of oxygen constituting the oxide of the major cations shown above in glass 3 in the oxide-based glass composition, and Cu represents the molar CuO content in the oxide-based glass composition.

[0054] The "O(P)" in Equation 3 is calculated as follows: When the P2O5 content in the oxide-based glass composition (molar basis) is M mol%, the number of oxygen atoms in the chemical formula of P2O5, which is 5, is used, and O(P) is calculated as "O(P) = M × 5". Similarly, for major cations other than P ions, the amount of oxygen constituting the oxide of each cation is calculated using the value of its content as an oxide in the oxide-based glass composition (molar basis) and the number of oxygen atoms contained in the oxide formed by each cation in its formal valence state. Thus, "O(others)" is calculated by subtracting O(P) from the total amount of oxygen calculated for the oxides of the major cations. When the CuO content in the oxide-based glass composition (molar basis) is N mol%, "A" is calculated as A1 = {O(P) - O(others)} × N.

[0055] As described above, the inventors have newly discovered that in a glass mainly composed of O ions as an anion, reducing the O / P ratio shifts the absorption of CuO in the red region to longer wavelengths, thereby suppressing a decrease in transmittance in the red region while increasing the CuO content. Furthermore, they have newly found that by using chemical species other than PO that coordinate to CuO with species having smaller ionic radii and lower valencies, the transmittance in the visible region (purple region to red region) can be increased as a result of 1) and 2) below. Based on these findings, glass 3 is defined based on A, which is calculated by formula 3, and its CuO content is determined accordingly. 1) Cu 2+ By shifting the absorption originating from this to longer wavelengths, the transmittance in the red region can be increased. 2) By making it possible to put glass into a liquid state at low temperatures, Cu will produce absorption in the violet region around a wavelength of 400 nm. + This can suppress the occurrence of [unclear].

[0056] Regarding glass 3, from the viewpoint of achieving both improved visible light transmittance and improved near-infrared cut capability, A1 is 2500 or higher, preferably 2800 or higher, and also 2900 or higher, 3000 or higher, 3100 or higher, 3200 or higher, 3300 or higher, 3400 or higher, 3500 or higher, 3600 or higher, 3700 or higher, 3800 or higher, 3900 or higher, 4000 or higher, 4100 or higher, 4200 or higher, and 4 The following are preferred in order: 300 or more, 4400 or more, 4500 or more, 4600 or more, 4700 or more, 4800 or more, 4900 or more, 5000 or more, 5100 or more, 5200 or more, 5300 or more, 5400 or more, 5500 or more, 5600 or more, 5700 or more, 5800 or more, 5900 or more, 6000 or more, 6100 or more, 6200 or more, 6300 or more, 6400 or more, and 6500 or more. On the other hand, from the viewpoint of further suppressing the decrease in thermal stability of the glass due to the large amount of Cu and O, the decrease in transmittance at the desired half-value wavelength, and / or the decrease in thermal stability or weather resistance of the glass due to insufficient O (others), A is preferably 20,000 or less, and more preferably 19,000 or less, 18,000 or less, 17,000 or less, 16,000 or less, 150,000 or less, 14,000 or less, 13,000 or less, 12,000 or less, 11,000 or less, 10,000 or less, 9,000 or less, and 8,000 or less. In addition, to achieve the desired half-value with thinner wall thicknesses, a larger value tends to be preferable.

[0057] In glass 4, the CuO content is determined based on A2 calculated by the following formula 4, where A2 is 700 or more.

[0058] (Formula 4) A2 = {O(P) - O(others)} × C

[0059] In Equation 4, C is the CuO content per molar volume of glass (unit: millimoles / cc). O(P) represents the amount of oxygen constituting the oxide of the P ion in the oxide-based glass composition, and O(others) represents the amount of oxygen obtained by subtracting O(P) from the amount of oxygen constituting the oxide of the above-mentioned major cations in the oxide-based glass composition.

[0060] Regarding glass 4, from the viewpoint of achieving both improved visible-range transmittance and improved near-infrared cut capability, A2 is preferably 700 or higher, more preferably 800 or higher, and more preferably 850 or higher, 890 or higher, 1000 or higher, 1100 or higher, 1200 or higher, 1300 or higher, 1400 or higher, 1500 or higher, 1600 or higher, 1700 or higher, and 1800 or higher, in that order. On the other hand, from the viewpoint of further suppressing the decrease in thermal stability of the glass due to the large amount of Cu and O, the decrease in transmittance at the desired half-value wavelength, and / or the decrease in thermal stability or weather resistance of the glass due to insufficient O (others), A2 is preferably 5000 or lower, more preferably 4000 or lower, 3500 or lower, 3000 or lower, 2500 or lower, and 2000 or lower. Note that in order to achieve the desired half-value transmittance with a thinner thickness, a larger value tends to be preferable.

[0061] Furthermore, in glass 5, the CuO content is α2% or more. α2 is a value calculated from the following formula 5.

[0062] (Formula 5) α² = 76522 × exp(-2.855 × R)

[0063] In equation 5, R is the O / P ratio.

[0064] Furthermore, for glass 6, the lower limit of the CuO content is determined by the CuO content per molar volume of the glass, as shown in formula 6 below.

[0065] (Formula 6) C - 3478 × exp(-2.278 × R) ≥ 0

[0066] In Equation 6, C is the CuO content per molar volume of glass (unit: millimoles / cc), and R is the O / P ratio.

[0067] The CuO content of glasses 1 to 6 is preferably 4.0% or more in terms of the oxide-based glass composition (molar basis), and is more preferably 5.0% or more, 6.0% or more, 7.0% or more, 7.5% or more, 8.0% or more, 8.5% or more, 9.0% or more, 9.5% or more, 10.0% or more, 10.5% or more, 11.0% or more, 11.5% or more, 12.0% or more, 12.5% ​​or more, 13.0% or more, 13.5% or more, 14.0% or more, 14.5% or more, 15.0% or more, 15.5% or more, 16.0% or more, 16.5% or more, 17.0% or more, 17.5% or more, 18.0% or more, 18.5% or more, 19.0% or more, 19.5% or more, and 20.0% or more, in that order. From the viewpoint of leaving room for the introduction of glass-forming components and maintaining the thermal stability of the glass, the CuO content is preferably 48.0% or less, and further preferably 47.0% or less, 46.0% or less, 45.0% or less, 44.0% or less, 43.5% or less, 43.0% or less, 42.5% or less, 42.0% or less, 41.5% or less, 41.0% or less, 40.5% or less, and 40. The following percentages are preferred in increasing order: 0% or less, 39.5% or less, 39.0% or less, 38.5% or less, 38.0% or less, 37.5% or less, 37.0% or less, 36.5% or less, 36.0% or less, 35.5% or less, 35.0% or less, 34.5% or less, 34.0% or less, 33.5% or less, 33.0% or less, 32.5% or less, 32.0% or less, 31.5% or less, and 31.0% or less.

[0068] As a transmittance characteristic calculated for a thickness of 0.11 mm, the wavelength λ at which the external transmittance, including reflection loss, is 50% is considered to be the transmittance characteristic. T For 50 to be in the range of 600nm to 650nm, the CuO content is preferably 15.0% or more in the oxide-based glass composition (molar basis), and is more preferably 15.5% or more, 16.0% or more, 16.5% or more, 17.0% or more, 17.5% or more, 18.0% or more, 18.5% or more, 19.0% or more, 19.5% or more, and 20.0% or more, in that order. As a transmittance characteristic calculated for a thickness of 0.21 mm, the wavelength λ at which the external transmittance, including reflection loss, is 50% T For 50 to be in the range of 600nm to 650nm, the CuO content is preferably 10.0% or more in the oxide-based glass composition (molar basis), and is more preferably 10.5% or more, 11.0% or more, 11.5% or more, 12.0% or more, 12.5% ​​or more, 13.0% or more, 13.5% or more, 14.0% or more, 14.5% or more, 15.0% or more, 15.5% or more, 16.0% or more, 16.5% or more, 17.0% or more, 17.5% or more, 18.0% or more, 18.5% or more, 19.0% or more, 19.5% or more, and 20.0% or more. As a transmittance characteristic calculated for a thickness of 0.25 mm, the wavelength λ at which the external transmittance, including reflection loss, is 50% is considered to be the transmittance characteristic. T For 50 to be in the range of 600nm to 650nm, the CuO content is preferably 10.0% or more in the oxide-based glass composition (molar basis), and is more preferably 10.5% or more, 11.0% or more, 11.5% or more, 12.0% or more, 12.5% ​​or more, 13.0% or more, 13.5% or more, 14.0% or more, 14.5% or more, 15.0% or more, 15.5% or more, 16.0% or more, 16.5% or more, 17.0% or more, 17.5% or more, 18.0% or more, 18.5% or more, 19.0% or more, 19.5% or more, and 20.0% or more. On the other hand, the transmittance characteristics calculated for a thickness of 0.25 mm show that when the CuO content is high, the wavelength at which the external transmittance, including reflection loss, becomes 50% is λ. T Since 50 may be below 600 nm, the CuO content is preferably 35.0% or less, and more preferably in the following order: 34.0% or less, 33.0% or less, 32.0% or less, 31.0% or less, 30.0% or less, 29.5% or less, 29.0% or less, 28.5% or less, 28.0% or less, 27.5% or less, 27.0% or less, 26.5% or less, 26.0% or less, 25.5% or less, 25.0% or less, 24.5% or less, 24.0% or less, 23.5% or less, 23.0% or less, 22.5% or less, 22.0% or less, 21.5% or less, 21.0% or less, 20.5% or less, and 20.0% or less. The wavelength λ at which the external transmittance, including reflection loss, is 50% at wavelengths above 550 nmT For λ50 to be 645 nm when the glass thickness is 0.25 mm or less, the CuO content is preferably 10.0% or more, based on oxide glass composition (on a molar basis), and more preferably in the following order: 10.5% or more, 11.0% or more, 11.5% or more, 12.0% or more, 12.5% or more, 13.0% or more, 13.5% or more, 14.0% or more, 14.5% or more, 15.0% or more, 15.5% or more, 16.0% or more, 16.5% or more, 17.0% or more, 17.5% or more, 18.0% or more, 18.5% or more, 19.0% or more, 19.5% or more, and 20.0% or more. Wavelength λ at which external transmittance including reflection loss becomes 50% at a wavelength of 550 nm or more T For λ50 to be 633 nm when the glass thickness is 0.25 mm or less, the CuO content is preferably 10.5% or more, based on oxide glass composition (on a molar basis), and more preferably in the following order: 11.0% or more, 11.5% or more, 12.0% or more, 12.5% or more, 13.0% or more, 13.5% or more, 14.0% or more, 14.5% or more, 15.0% or more, 15.5% or more, 16.0% or more, 16.5% or more, 17.0% or more, 17.5% or more, 18.0% or more, 18.5% or more, 19.0% or more, 19.5% or more, and 20.0% or more.

[0069] In glass 2 and glass 4, the value of C is preferably 3.0 or higher, and is most preferably 3.1 or higher, 3.3 or higher, 3.5 or higher, 3.7 or higher, 3.9 or higher, 4.0 or higher, 4.1 or higher, 4.2 or higher, 4.3 or higher, 4.4 or higher, 4.5 or higher, 4.6 or higher, 4.7 or higher, 4.8 or higher, 4.9 or higher, 5.0 or higher, 5.1 or higher, 5.2 or higher, 5.3 or higher, and 5.4 or higher to 5.5 or higher. From the viewpoint of leaving room for the introduction of glass-forming components and maintaining the thermal stability of the glass, the value of C is preferably 16.0 or less, and more preferably 15.0 or less, 14.0 or less, 13.5 or less, 13.0 or less, 12.5 or less, 12.0 or less, 11.9 or less, 11.8 or less, 11.7 or less, 11.6 or less, 11.5 or less, 11.4 or less, 11.3 or less, 11.2 or less, 11.1 or less, and 11.0 or less. The following values ​​are preferred in descending order: 10.9 or less, 10.8 or less, 10.7 or less, 10.6 or less, 10.5 or less, 10.4 or less, 10.3 or less, 10.2 or less, 10.1 or less, 10.0 or less, 9.9 or less, 9.8 or less, 9.7 or less, 9.6 or less, 9.5 or less, 9.4 or less, 9.3 or less, 9.2 or less, 9.1 or less, 9.0 or less, 8.9 or less, 8.8 or less, 8.7 or less, 8.6 or less, and 8.5 or less.

[0070] In glass 1 to 6, the CuO content can be α3% or more. α3 is a value calculated from the following formula 7.

[0071] (Formula 7) α3=(70400×0.25 / d)×exp(-2.855×R)

[0072] In Equation 7, R is the O / P ratio. d can take values ​​greater than 0 and less than or equal to 0.25. For example, d can be 0.25, 0.24, 0.23, 0.22, 0.21, 0.20, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, 0.11, 0.10, 0.09, 0.08, 0.07, 0.06, 0.05, 0.04, 0.03, 0.02, 0.01, etc. However, the value of d is not limited to these. To achieve the desired half-value of transmittance with thinner wall thicknesses, a smaller value of d tends to be preferable.

[0073] For example, when d = 0.11, the CuO content can be α3% or more, and α3 is calculated by the following formula. α3=(70400×0.25 / 0.11)×exp(-2.855×R)

[0074] When the thickness of a glass plate is D (mm) such that the external transmittance for light with a wavelength of 633 nm is 50%, in one embodiment, d = D can be expressed in equation 7 above. In this case, α3 is calculated by the following equation. α3=(70400×0.25 / D)×exp(-2.855×R)

[0075] For glasses 1 to 6, the lower limit of the CuO content can also be the value defined by the following formula 8, based on the CuO content per molar volume of the glass.

[0076] (Formula 8) C-3200×0.25 / d×exp(-2.855×R)≧0

[0077] In Equation 8, d can take a value greater than 0 and less than or equal to 0.25. For example, d can be 0.25, 0.24, 0.23, 0.22, 0.21, 0.20, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, 0.11, 0.10, 0.09, 0.08, 0.07, 0.06, 0.05, 0.04, 0.03, 0.02, 0.01, etc. However, the value of d is not limited to these. To achieve the desired half-value of transmittance with thinner wall thicknesses, a smaller value of d tends to be preferable.

[0078] For example, when d = 0.11, equation 8 is as follows: C-3300×0.25 / 0.11×exp(-2.855×R)≧0

[0079] When the thickness of a glass plate is D (mm) such that the external transmittance for light with a wavelength of 633 nm is 50%, in one embodiment, d = D can be expressed in equation 8 above. In this case, equation 8 is as follows:

[0080] Regarding the CuO content, each of the glasses 1 to 6 may also satisfy one or more of the requirements of the formulas relating to the other glasses.

[0081] Glasses 1-6 contain P ions as essential cations. As mentioned earlier, a low O / P ratio is preferable from the viewpoint of achieving both improved visible light transmittance and improved near-infrared cut capability. To lower the O / P ratio, it is preferable to increase the P2O5 content. From this perspective, the P2O5 content in the oxide-based glass composition (molar basis) is preferably 33.0% or more, and is more preferably 34.0% or more, 35.0% or more, 36.0% or more, 37.0% or more, 38.0% or more, 39.0% or more, 40.0% or more, 40.5% or more, 41.0% or more, 41.5% or more, 42.0% or more, 42.5% or more, 43.0% or more, 43.5% or more, 44.0% or more, 44.5% or more, 45.0% or more, 45.5% or more, 46.0% or more, 46.5% or more, 47.0% or more, 47.5% or more, 48.0% or more, 48.5% or more, 49.0% or more, 49.5% or more, and 50.0% or more, in that order. Since P2O5 itself is a component that does not possess near-infrared absorption capabilities, from the viewpoint of increasing the CuO content, which does possess near-infrared absorption capabilities, the P2O5 content is preferably 72.0% or less, and more preferably in the following order: 71.0% or less, 70.0% or less, 69.5% or less, 69.0% or less, 68.5% or less, 68.0% or less, 67.5% or less, 67.0% or less, 66.5% or less, 66.0% or less, 65.5% or less, 65.0% or less, 64.5% or less, 64.0% or less, 63.5% or less, 63.0% or less, 62.5% or less, 62.0% or less, 61.5% or less, 61.0% or less, 60.5% or less, and 60.0% or less. Furthermore, having a P2O5 content below the above values ​​is also preferable from the viewpoint of further suppressing the decrease in weather resistance and / or suppressing the decrease in melting properties.

[0082] To obtain the desired transmittance characteristics, it is desirable that the oxide-based glass composition of the above glass mainly consists of P2O5, Li2O, and CuO. From this point of view, the total content of P2O5, Li2O, and CuO (P2O5 + Li2O + CuO) is preferably 50.0% or more, and more preferably in the order of 55.0% or more, 60.0% or more, 65.0% or more, 70.0% or more, 75.0% or more, 80.0% or more, 83.0% or more, 86.0% or more, 88.0% or more, and 90.0% or more. The above glass contains P ions, Li ions, and Cu ions as essential cations, and further contains one or more cations selected from the group of major cations in order to obtain the thermal stability and / or chemical durability of the glass. Therefore, the total content (P2O5 + Li2O + CuO) is less than 100%, preferably 9.9% or less, and more preferably in the following order: 99.8% or less, 99.7% or less, 99.6% or less, 99.5% or less, 99.4% or less, 99.2% or less, 99.0% or less, 98.0% or less, 97.0% or less, 96.0% or less, 95.0% or less, 94.0% or less, 93.0% or less, 92.0% or less, 91.0% or less, 90.0% or less, 89.0% or less, 88.0% or less, 87.0% or less, 86.0% or less, and 85.0% or less.

[0083] In one embodiment, the wavelength λ is such that the external transmittance, including reflection loss, is 50% when calculated based on a thickness of 0.11 mm. T For 50 to be in the range of 600nm to 650nm, the total content of P2O5, Li2O, and CuO (P2O5 + Li2O + CuO) is preferably 84.0% or more in terms of oxide-based glass composition (molar basis), with 85.0% or more, 86.0% or more, 87.0% or more, 88.0% or more, 89.0% or more, and 90.0% or more being the most preferred values. As a transmittance characteristic calculated for a thickness of 0.21 mm, the wavelength λ at which the external transmittance, including reflection loss, is 50% is considered to be the transmittance characteristic. T For 50 to be in the range of 600nm to 650nm, P2O 5、The total content of Li2O and CuO (P2O5 + Li2O + CuO) is preferably 80.0% or more in the oxide-based glass composition (molar basis), and is more preferably 81.0% or more, 82.0% or more, 83.0% or more, 84.0% or more, 85.0% or more, 86.0% or more, 87.0% or more, 88.0% or more, 89.0% or more, and 90.0% or more, in that order. As a transmittance characteristic calculated for a thickness of 0.25 mm, the wavelength λ at which the external transmittance, including reflection loss, is 50% is considered to be the transmittance characteristic. T For 50 to be in the range of 600nm to 650nm, the total content of P2O5, Li2O, and CuO (P2O5 + Li2O + CuO) is preferably 75.0% or more in the oxide-based glass composition (molar basis), and is more preferably 76.0% or more, 77.0% or more, 78.0% or more, 79.0% or more, 80.0% or more, 81.0% or more, 82.0% or more, 83.0% or more, 84.0% or more, 85.0% or more, 86.0% or more, 87.0% or more, 88.0% or more, 89.0% or more, and 90.0% or more, in that order. The wavelength λ at which the external transmittance, including reflection loss, is 50% at wavelengths above 550 nm T In order for the glass thickness at which 50 is 645 nm to be 0.25 mm or less, the total content of P2O5, Li2O, and CuO (P2O5 + Li2O + CuO) is preferably 80.0% or more in the oxide-based glass composition (molar basis), and is more preferably 81.0% or more, 82.0% or more, 83.0% or more, 84.0% or more, 85.0% or more, 86.0% or more, 87.0% or more, 88.0% or more, 89.0% or more, and 90.0% or more, in that order. The wavelength λ at which the external transmittance, including reflection loss, is 50% at wavelengths above 550 nm T For the glass thickness at which 50 is 633 nm to be 0.25 mm or less, the total content of P2O5, Li2O, and CuO (P2O5 + Li2O + CuO) is preferably 81.0% or more in the oxide-based glass composition (molar basis), and is more preferably 82.0% or more, 83.0% or more, 84.0% or more, 85.0% or more, 86.0% or more, 87.0% or more, 88.0% or more, 89.0% or more, and 90.0% or more, in that order. Examples of glass that fall under one of the above forms include the glass described in Examples 1 to 60 below.

[0084] On the other hand, as another form, for glass where the molar ratio of the total content of MgO, CaO, SrO, BaO, and ZnO (MgO+CaO+SrO+BaO+ZnO) to the total content of Li2O, Na2O, and K2O (Li2O+Na2O+K2O) ((MgO+CaO+SrO+BaO+ZnO) / (Li2O+Na2O+K2O)) is 2.0 or higher, the wavelength λ at which the external transmittance, including reflection loss, is 50% is calculated as the transmittance characteristic for a thickness of 0.11 mm. T For 50 to be in the range of 600nm to 650nm, the total content of P2O5, Li2O, and CuO (P2O5 + Li2O + CuO) is preferably 65.0% or more in terms of oxide-based glass composition (molar basis), with 66.0% or more, 67.0% or more, 68.0% or more, 69.0% or more, and 70.0% or more being the most preferred values. For the other form described above, the wavelength λ at which the external transmittance, including reflection loss, is 50% is calculated as the transmittance characteristic when calculated for a thickness of 0.21 mm. T For 50 to be in the range of 600nm to 650nm, the total content of P2O5, Li2O, and CuO (P2O5 + Li2O + CuO) is preferably 60.0% or more in terms of oxide-based glass composition (molar basis), with 61.0% or more, 62.0% or more, 63.0% or more, 64.0% or more, and 65.0% or more being the most preferred values. For the other form described above, the wavelength λ at which the external transmittance, including reflection loss, is 50% is calculated as the transmittance characteristic when calculated for a thickness of 0.25 mm. T For 50 to be in the range of 600nm to 650nm, the total content of P2O5, Li2O, and CuO (P2O5 + Li2O + CuO) is preferably 55.0% or more in the oxide-based glass composition (molar basis), with 56.0% or more, 57.0% or more, 58.0% or more, 59.0% or more, and 60.0% or more being the most preferred values. For the other form described above, the wavelength λ at which the external transmittance, including reflection loss, is 50% at wavelengths of 550 nm or higher. TFor the glass thickness at which 50 is 645 nm to be 0.25 mm or less, the total content of P2O5, Li2O, and CuO (P2O5 + Li2O + CuO) is preferably 60.0% or more in the oxide-based glass composition (molar basis), and is more preferably 61.0% or more, 62.0% or more, 63.0% or more, 64.0% or more, and 65.0% or more, in that order. For the other form described above, the wavelength λ at which the external transmittance, including reflection loss, is 50% at wavelengths of 550 nm or higher. T For the glass thickness at which 50 is 633 nm to be 0.25 mm or less, the total content of P2O5, Li2O, and CuO (P2O5 + Li2O + CuO) is preferably 61.0% or more in the oxide-based glass composition (molar basis), with 62.0% or more, 63.0% or more, 64.0% or more, 65.0% or more, and 66.0% or more being the most preferred values. Examples of glass that fall under another form described above include those shown in Examples 61 to 66 below.

[0085] The group of major cations previously described for glasses 3 and 4 includes B ions and Si ions. On the other hand, the group of major cations previously described for glasses 1, 2, 5, and 6 does not include B ions or Si ions, which tend to increase the dissolution temperature. In one form, glasses 1 to 6 can be glasses containing one or both B ions and Si ions, which tend to shift the half value to the shorter wavelength side, from the viewpoint of increasing the near-infrared cutting ability of the glass and improving the transmittance in the visible range, and in another form, they can be glasses that do not contain either B ions or Si ions.

[0086] For glass 1 and glass 2, in terms of oxide-based glass composition (molar basis), from the viewpoint of improving the transmittance in the visible range, the total content of B2O3 and SiO2 (B2O3 + SiO2) is 3.0% or less, preferably 2.5% or less, and more preferably 2.0% or less, 1.5% or less, 1.0% or less, and 0.5% or less, in that order.

[0087] For glasses 3 to 6, in terms of oxide-based glass composition (molar basis), from the viewpoint of further improving the transmittance in the visible range, the total content of B2O3 and SiO2 (B2O3 + SiO2) is preferably 3.0% or less, and more preferably in the order of 2.5% or less, 2.0% or less, 1.5% or less, 1.0% or less, and 0.5% or less.

[0088] In glass 1 to 6, the total content of B2O3 and SiO2 (B2O3 + SiO2) can be 0%, 0% or more, or greater than 0%.

[0089] In glass 1 to 6, from the viewpoint of further improving the transmittance in the visible range, the content of B2O3 is preferably 3.0% or less, and more preferably in the order of 2.5% or less, 2.0% or less, 1.5% or less, 1.0% or less, and 0.5% or less. The B2O3 content can also be 0%. On the other hand, for glasses 1 to 6, when rough melting of the glass is performed in a quartz crucible to promote glass homogenization, the SiO2 content is preferably greater than 0%, with the order of preference being 0.01% or more, 0.02% or more, 0.03% or more, 0.04% or more, 0.05% or more, 0.1% or more, 0.2% or more, and 0.3% or more. However, the introduction of excessive SiO2 into the glass tends to reduce the optical homogeneity of the glass. From this point of view, for glasses 1 to 6, the SiO2 content is preferably 2.0% or less, with the order of preference being 1.4% or less, 0.9% or less, 0.8% or less, 0.6% or less, and 0.4% or less.

[0090] Glasses 1 to 6 contain Li ions as essential cations. Compared to various glass components, Li2O has a high ability to maintain CuO absorption in the long-wavelength range and also has a small adverse effect on weather resistance. From this viewpoint, the Li2O content is preferably 0.1% or more, and is more preferably 0.5% or more, 1.0% or more, 1.5% or more, 2.0% or more, 2.5% or more, 3.0% or more, 3.5% or more, 4.0% or more, 4.5% or more, 5.0% or more, 5.5% or more, 6.0% or more, 6.5% or more, 7.0% or more, 7.5% or more, and 8.0% or more, in that order. On the other hand, from the viewpoint of ensuring the thermal stability of the glass and / or further suppressing and maintaining the deterioration of weather resistance, the Li2O content is preferably 35.0% or less, and more preferably in the following order: 34.0% or less, 33.0% or less, 32.0% or less, 31.0% or less, 30.0% or less, 29.5% or less, 29.0% or less, 28.5% or less, 28.0% or less, 27.5% or less, 27.0% or less, 26.5% or less, 26.0% or less, 25.5% or less, 25.0% or less, 24.5% or less, 24.0% or less, 23.5% or less, 23.0% or less, 22.5% or less, 22.0% or less, 21.5% or less, 21.0% or less, 20.5% or less, and 20.0% or less.

[0091] In glasses 1 to 6, the total content of MgO and Al2O3 (MgO + Al2O3) is preferably 8.0% or less, and more preferably 7.5% or less, from the viewpoint of improving solubility and transmittance in the visible range. The order of preference is 7.0% or less, 6.5% or less, 6.0% or less, 5.5% or less, 5.0% or less, 4.5% or less, 4.0% or less, 3.5% or less, 3.0% or less, 2.5% or less, 2.0% or less, 1.8% or less, 1.6% or less, 1.5% or less, and 1.4% or less, and it may also be 0%. On the other hand, the total content of MgO and Al2O3 (MgO + Al2O3) can be greater than 0% from the viewpoint of improving the weather resistance of the glass and improving the mechanical strength of the glass, and is preferably 0.1% or more, in the order of 0.2% or more, 0.3% or more, 0.4% or more, 0.5% or more, 0.6% or more, 0.7% or more, 0.8% or more, 0.9% or more, 1.0% or more, 1.1% or more, and 1.3% or more.

[0092] Al2O3 is a component that can particularly contribute to improving weather resistance. The Al2O3 content can be 0%, 0% or more, or greater than 0%. From the viewpoint of improving weather resistance, it is preferably 0.1% or more, and more preferably in the order of 0.2% or more, 0.3% or more, 0.4% or more, 0.5% or more, 0.6% or more, 0.7% or more, 0.9% or more, 1.1% or more, 1.3% or more, and 1.5% or more. On the other hand, from the viewpoint of further suppressing the decrease in transmittance in the visible range, the Al2O3 content is preferably 8.0% or less, and more preferably in the order of 7.5% or less, 7.0% or less, 6.0% or less, 5.5% or less, 5.0% or less, 4.5% or less, 4.0% or less, 3.5% or less, 3.0% or less, and 2.5% or less. In one embodiment, prioritizing the improvement of near-infrared absorption characteristics over maintaining the weather resistance of the glass, and suppressing the short-wavelength shift of CuO absorption to further increase the transmittance in the visible range and improve near-infrared absorption characteristics, the Al2O3 content is preferably less than 2.0%, and more preferably in the order of 1.9% or less, 1.8% or less, 1.7% or less, 1.6% or less, 1.5% or less, 1.4% or less, 1.3% or less, 1.2% or less, 1.1% or less, 1.0% or less, 0.9% or less, 0.8% or less, 0.7% or less, 0.6% or less, and 0.5% or less.

[0093] MgO is a component that can be added as appropriate to adjust the thermal stability of the glass, but it tends to make it difficult to increase the CuO content because it shifts the absorption of CuO to the shorter wavelength side. Also, the fusionability of the glass tends to decrease with increasing MgO content. From these viewpoints, the MgO content is preferably 9.0% or less, and more preferably 8.0% or less, 7.0% or less, 6.0% or less, 5.0% or less, 4.0% or less, 3.0% or less, and 2.0% or less, in that order. The MgO content can also be 0%. In one embodiment, from the viewpoint of improving the mechanical strength of the glass, the MgO content can be greater than 0%, preferably 0.5% or more, and more preferably 1.0% or more.

[0094] La2O3 is a component that can contribute to improving the weather resistance of glass without impairing its near-infrared absorption properties. The La2O3 content is preferably 0.10% or more, and more preferably 0.15% or more, 0.18% or more, and 0.21% or more, in that order. On the other hand, from the viewpoint of further suppressing the decrease in transmittance in the visible range, the La2O3 content is preferably 8.0% or less, and more preferably 7.0% or less, 6.5% or less, 6.0% or less, 5.5% or less, 5.0% or less, 4.5% or less, 4.0% or less, 3.5% or less, 3.0% or less, 2.5% or less, 2.0% or less, 1.5% or less, and 1.0% or less, in that order.

[0095] Y2O3 is also a component that can contribute to improving the weather resistance of glass without impairing its near-infrared absorption properties. The Y2O3 content is preferably 0.10% or more, and is more preferably 0.15% or more, 0.20% or more, 0.25% or more, 0.30% or more, 0.35% or more, 0.40% or more, 0.45% or more, and 0.50% or more, in that order. On the other hand, from the viewpoint of further suppressing the decrease in transmittance in the visible range, the Y2O3 content is preferably 8.0% or less, and is more preferably 7.0% or less, 6.5% or less, 6.0% or less, 5.5% or less, 5.0% or less, 4.5% or less, 4.0% or less, 3.5% or less, 3.0% or less, 2.5% or less, 2.0% or less, 1.5% or less, and 1.0% or less, in that order. Y2O3 can also be introduced from the viewpoint of increasing the molar volume of glass without increasing the specific gravity of the glass.

[0096] Gd2O3 is also a component that can contribute to improving weather resistance. The Gd2O3 content is preferably 0.10% or more, and more preferably 0.15% or more, 0.18% or more, and 0.21% or more, in that order. On the other hand, from the viewpoint of further suppressing the decrease in transmittance in the visible range, the Gd2O3 content is preferably 8.0% or less, and more preferably 7.0% or less, 6.5% or less, 6.0% or less, 5.5% or less, 5.0% or less, 4.5% or less, 4.0% or less, 3.5% or less, 3.0% or less, 2.5% or less, 2.0% or less, 1.5% or less, and 1.0% or less, in that order.

[0097] Furthermore, the oxide-based glass composition may or may not include one or more other rare earth oxides such as Lu2O3 and Sc2O3. Since these components are generally expensive, the content of rare earth oxides other than La2O3, Y2O3, and Gd2O3 (the total content if two or more are included) is preferably 2.5% or less, preferably 1.5% or less, 1.0%, 0.5% or less, and may even be 0%.

[0098] In glass 1 to 6, the total content of Al2O3, La2O3, Y2O3, and Gd2O3 (Al2O3 + La2O3 + Y2O3 + Gd2O3) is preferably 0.1% or more from the viewpoint of improving weather resistance, and is more preferably 0.15% or more, 0.20% or more, 0.25% or more, 0.30% or more, 0.35% or more, 0.40% or more, 0.45% or more, and 0.50% or more, in that order. On the other hand, the total content (Al2O3 + La2O3 + Y2O3 + Gd2O3) is preferably 8.0% or less from the viewpoint of ensuring the thermal stability of the glass and / or lowering the melting temperature, and is more preferably 7.0% or less, 6.5% or less, 6.0% or less, 5.5% or less, 5.0% or less, 4.5% or less, 4.0% or less, 3.5% or less, 3.0% or less, 2.5% or less, 2.0% or less, 1.5% or less, and 1.0% or less, in that order.

[0099] Cationic compounds with a formal valency of +2 tend not to have a significant effect on either the improvement of transmittance in the visible range or the weather resistance when considering the overall glass composition. Therefore, the total content of oxides of cations with a formal valency of +2, namely MgO, CaO, SrO, and BaO, is preferably such that the molar ratio ((MgO+CaO+SrO+BaO) / Li2O) to the content of the essential cation Li ion oxide Li2O is 2.0 or less, and more preferably 1.5 or less, 1.3 or less, 1.2 or less, 1.1 or less, 1.0 or less, 0.9 or less, 0.8 or less, 0.7 or less, 0.6 or less, 0.5 or less, 0.4 or less, 0.3 or less, and 0.2 or less. As described later, the above components are optional components that can be used to adjust the half value together with some alkaline components.

[0100] Furthermore, regarding the total content of oxides of cations with a formal valency of +2, namely MgO, CaO, SrO, BaO, and ZnO, from the viewpoint of improving transmittance in the visible range, it is preferable that the molar ratio ((MgO+CaO+SrO+BaO+ZnO) / Li2O) to the content of the oxide Li2O, which is an essential cation, be 2.0 or less, and more preferably 1.5 or less, 1.3 or less, 1.2 or less, 1.1 or less, 1.0 or less, 0.9 or less, 0.8 or less, 0.7 or less, 0.6 or less, 0.5 or less, 0.4 or less, 0.3 or less, and 0.2 or less. On the other hand, from the viewpoint of improving weather resistance, it is preferable that (MgO+CaO+SrO+BaO+ZnO) / Li2O) be 2.0 or more, and more preferably 2.5 or more, 3.0 or more, 3.5 or more, and 4.0 or more, in that order. As described later, the above components are optional components that can be used to adjust the half value together with some alkaline components.

[0101] The BaO content is 0%. It can be 0% or more, or greater than 0%. BaO is a component that can improve weather resistance when introduced in a certain amount, and furthermore, the change in T600 due to its introduction is small. T600 will be discussed later. BaO can be added to improve the thermal stability of the glass and to adjust its fusion properties. BaO can also be used to adjust the concentration of CuO. The BaO content is preferably 0.5% or more, and is more preferably 1.0% or more, 1.5% or more, 2.0% or more, 2.5% or more, 3.0% or more, 3.5% or more, 4.0% or more, 4.5% or more, 5.0% or more, 5.5% or more, 6.0% or more, 6.5% or more, and 7.0% or more, in that order. However, excessive introduction tends to decrease T400. T400 will be discussed later. From the above viewpoint, the BaO content is preferably 36.0% or less, and is more preferably 35.0% or less, 34.0% or less, 33.0% or less, 32.0% or less, 31.0% or less, 30.0% or less, 29.0% or less, 28.0% or less, 27.0% or less, 26.0% or less, 26.0% or less, 25.0% or less, 24.0% or less, 23.0% or less, 22.0% or less, 21.0% or less, 20.0% or less, 19.0% or less, 18.0% or less, 17.0% or less, 16.0% or less, 15.0% or less, 14.0% or less, 13.0% or less, 12.0% or less, 11.0% or less, 10.0% or less, and 9.0% or less, in that order.

[0102] The SrO content is 0%. It can be 0% or more or greater than 0%. Similar to BaO, SrO is a component that does not significantly reduce weather resistance and can be added as appropriate for reasons such as adjusting the thermal stability of the glass. SrO can also be used to adjust the concentration of CuO. The SrO content is preferably 0.5% or more, and is more preferably 1.0% or more, 1.5% or more, 2.0% or more, 2.5% or more, 3.0% or more, 3.5% or more, 4.0% or more, 4.5% or more, 5.0% or more, 5.5% or more, 6.0% or more, 6.5% or more, and 7.0% or more, in that order. However, since excessive introduction tends to decrease T400, the SrO content is preferably 30.0% or less, and is more preferably 29.0% or less, 28.0% or less, 27.0% or less, 26.0% or less, 26.0% or less, 25.0% or less, 24.0% or less, 23.0% or less, 22.0% or less, 21.0% or less, 20.0% or less, 19.0% or less, 18.0% or less, 17.0% or less, 16.0% or less, 15.0% or less, 14.0% or less, 13.0% or less, 12.0% or less, 11.0% or less, 10.0% or less, and 9.0% or less, in that order.

[0103] The CaO content is 0%. It can be 0% or more or greater than 0%. CaO is a component that does not significantly reduce weather resistance and can be added as appropriate for reasons such as adjusting the thermal stability of the glass. CaO can also be used to adjust the concentration of CuO. The CaO content is preferably 0.5% or more, and preferably 1.0% or more, 1.5% or more, 2.0% or more, 2.5% or more, 3.0% or more, 3.5% or more, 4.0% or more, 4.5% or more, 5.0% or more, 5.5% or more, 6.0% or more, 6.5% or more, and 7.0% or more. However, since excessive introduction tends to lower T400, the CaO content is preferably 30.0% or less, and is more preferably 29.0% or less, 28.0% or less, 27.0% or less, 26.0% or less, 26.0% or less, 25.0% or less, 24.0% or less, 23.0% or less, 22.0% or less, 21.0% or less, 20.0% or less, 19.0% or less, 18.0% or less, 17.0% or less, 16.0% or less, 15.0% or less, 14.0% or less, 13.0% or less, 12.0% or less, 11.0% or less, 10.0% or less, and 9.0% or less, in that order.

[0104] Among the cations included in the group of major cations described above, Na ions, K ions, and Zn ions tend to worsen the weather resistance of glass, making it difficult to freely use them in place of the essential cation, Li ions. In addition to this point, from the viewpoint of improving transmittance in the visible or near-infrared region, in glasses 1 to 6, the ratio of the total content of Na2O, K2O, and ZnO to the Li2O content ((Na2O+K2O+ZnO) / Li2O) is preferably 2.4 or less, and more preferably 2.3 or less, in the order of 2.2 or less, 2.1 or less, 2.0 or less, 1.9 or less, 1.8 or less, 1.7 or less, 1.6 or less, 1.5 or less, 1.4 or less, 1.3 or less, 1.2 or less, 1.1 or less, 0.9 or less, 0.8 or less, 0.7 or less, 0.6 or less, 0.5 or less, 0.4 or less, 0.3 or less, 0.2 or less, 0.1 or less, and 0.05 or less, and can also be 0.00. On the other hand, from the viewpoint of suppressing the cost of glass raw materials, the molar ratio ((Na2O+K2O+ZnO) / Li2O) can be 0, 0 or more, or greater than 0. From the viewpoint of promoting the reduction of Tg and Tm, which will be described later, by mixing multiple components, it is preferable that it be 0.05 or more, and it can also be 0.1 or more, 0.2 or more, or 0.3 or more.

[0105] Furthermore, the higher the content of Na, K, and Zn ions, the more difficult it becomes to introduce a large amount of P2O5 to maintain weather resistance, and as a result, it becomes difficult to introduce a desirable amount of P2O5. From this viewpoint and from the viewpoint of suppressing the deterioration of weather resistance as described above, the total content of Na2O, K2O, and ZnO (Na2O+K2O+ZnO) is preferably 30.0% or less, and more preferably in the order of 25.0% or less, 20.0% or less, 15.0% or less, 12.0% or less, 10.0% or less, 9.0% or less, 8.0% or less, 7.0% or less, 6.0% or less, 5.0% or less, 4.0% or less, 3.0% or less, 2.0% or less, and 1.0% or less. The total content may also be 0%. On the other hand, from the viewpoint of suppressing the raw material cost of glass, the total content (Na2O+K2O+ZnO) may be 1.0% or more, 2.0% or more, 3.0% or more, or 5.0% or more.

[0106] The Na2O content can be 0%, 0% or more, or greater than 0%. Excessive Na2O introduction tends to reduce weather resistance. For this reason, the Na2O content is preferably 20.0% or less, and more preferably 19.0% or less, 18.0% or less, 17.0% or less, 16.0% or less, 15.0% or less, 14.0% or less, 13.0% or less, 12.0% or less, 11.0% or less, 10.0% or less, 9.0% or less, and 8.0% or less, in that order. On the other hand, Na2O is an easily obtainable and inexpensive raw material, and can be added as appropriate to improve solubility, so the Na2O content can be, for example, 0.5% or more, and can also be 1.0% or more, 1.5% or more, 2.0% or more, 2.5% or more, 3.0% or more, 3.5% or more, 4.0% or more, and 5.0% or more.

[0107] The K2O content can be 0%, 0% or more, or greater than 0%. Excessive K2O introduction tends to reduce weather resistance. Furthermore, it tends to shorten the wavelength of CuO absorption, so it is desirable not to introduce it actively. From these viewpoints, the K2O content is preferably 20.0% or less, and more preferably 19.0% or less, 18.0% or less, 17.0% or less, 16.0% or less, 15.0% or less, 14.0% or less, 13.0% or less, 12.0% or less, 11.0% or less, 10.0% or less, 9.0% or less, and 8.0% or less, in that order. On the other hand, K2O may be added as appropriate to improve the fusion properties of the glass. From this perspective, the K2O content is preferably 0.2% or more, and is more preferably 0.5% or more, 1.0% or more, 1.5% or more, 2.0% or more, 2.5% or more, 3.0% or more, 3.5% or more, 4.0% or more, and 5.0% or more, in that order.

[0108] The Cs2O content can be 0%, 0% or more, or greater than 0%. Since Cs2O also tends to reduce weather resistance, it is desirable not to actively introduce it. The Cs2O content is more preferably 15.0% or less, 14.0% or less, 13.0% or less, 12.0% or less, 11.0% or less, 10.0% or less, 9.0% or less, 8.0% or less, 7.0% or less, and 6.0% or less, in that order. On the other hand, in order to adjust thermal stability and meltability, the Cs2O content can be 0.5% or more, and can also be 1.0% or more, 1.5% or more, 2.0% or more, 2.5% or more, 3.0% or more, 3.5% or more, and 4.0% or more.

[0109] From the viewpoint of improving the fusion properties of the glass, the total content of Li2O, Na2O, and K2O (Li2O + Na2O + K2O) is preferably 1.8% or more, and is more preferably 2.1% or more, 2.3% or more, 2.5% or more, 3.5% or more, 4.5% or more, 5.5% or more, 6.5% or more, 7.5% or more, 8.5% or more, 9.5% or more, 10.0% or more, and 10.5% or more, in that order. On the other hand, from the viewpoint of further suppressing the deterioration of weather resistance, the total content (Li2O + Na2O + K2O) is preferably 35.0% or less, and is more preferably 33.5% or less, 32.5% or less, 31.5% or less, 30.5% or less, 29.5% or less, 28.5% or less, 27.5% or less, 26.5% or less, 25.5% or less, 24.5% or less, 23.5% or less, 21.5% or less, 20.5% or less, 19.5% or less, 18.5% or less, 17.5% or less, 16.6% or less, 15.5% or less, 14.5% or less, and 13.5% or less, in that order. Having a total content (Li2O + Na2O + K2O) below the above value is preferable from the standpoint of avoiding the increase in the expansion and contraction of the glass due to an increase in the coefficient of thermal expansion, which can lead to stress on the glass and cause chipping or cracking when the volume change of the glass is restricted by other components.

[0110] From the viewpoint of suppressing the deliquescence of glass, the total content of Na2O and K2O (Na2O + K2O) is preferably 30.0% or less, and is more preferably 29.0% or less, 28.0% or less, 27.0% or less, 26.0% or less, 25.0% or less, 24.0% or less, 23.0% or less, 22.0% or less, 21.0% or less, 20.0% or less, 19.0% or less, 18.0% or less, 17.0% or less, 16.0% or less, 15.0% or less, 14.0% or less, 13.0% or less, 12.0% or less, 11.0% or less, 10.0% or less, 9.0% or less, 8.0% or less, 7.0% or less, 6.0% or less, 5.0% or less, 4.0% or less, 3.0% or less, 2.0% or less, 1.0% or less, and 0.5% or less, in that order. By reducing the total content of Na2O and K2O (Na2O + K2O) to 0%, it is possible to obtain glass with even lower deliquescence. On the other hand, from the viewpoint of suppressing the meltability of the glass and reducing the decrease in T600 while suppressing the raw material costs of the glass, the total content (Na2O + K2O) can be set to 1.0% or more, and further to 2.0% or more, 3.0% or more, 4.0% or more, 5.0% or more, 6.0% or more, 7.0% or more, 8.0% or more, 9.0% or more, 10.0% or more, 11.0% or more, 12.0% or more, 13.0% or more, 14.0% or more, and 15.0% or more.

[0111] When adjusting the thickness of the glass, CuO can be substituted with other components. In this case, by using glass with a total content of Na2O, K2O, CaO, SrO, and BaO (Na2O+K2O+CaO+SrO+BaO) of 0% or more, the CuO concentration can be adjusted without significantly changing the position of near-infrared absorption. The total content (Na2O+K2O+CaO+SrO+BaO) is preferably 0.5% or more, and is more preferably 1.0% or more, 1.5% or more, 2.0% or more, 2.5% or more, 3.0% or more, 3.5% or more, 4.0% or more, 4.5% or more, 5.0% or more, 5.5% or more, 6.0% or more, 6.5% or more, and 7.0% or more, in that order. However, since excessive introduction tends to decrease T400, the total content (Na2O+K2O+CaO+SrO+BaO) is preferably 36.0% or less, and is more preferably 35.0% or less, 34.0% or less, 33.0% or less, 32.0% or less, 31.0% or less, 30.0% or less, 29.0% or less, 28.0% or less, 27.0% or less, 26.0% or less, 26.0% or less, 25.0% or less, 24.0% or less, 23.0% or less, 22.0% or less, 21.0% or less, 20.0% or less, 19.0% or less, 18.0% or less, 17.0% or less, 16.0% or less, 15.0% or less, 14.0% or less, 13.0% or less, 12.0% or less, 11.0% or less, 10.0% or less, and 9.0% or less, in that order. From the perspective of maximizing the near-infrared absorption characteristics of glass, the total content (Na2O + K2O + CaO + SrO + BaO) can be 8.0% or less, 7.0% or less, 6.0% or less, 5.0% or less, or 4.0% or less.

[0112] Regarding weather resistance, the suppression of glass deliquescence and the suppression of the formation of precipitates on the glass surface under high temperature and high humidity conditions, or both, can be used as indicators of weather resistance. This point will be discussed further later. To further improve weather resistance, the introduction of Al2O3 is more preferable, followed by the introduction of one or more of Y2O3, La2O3, and Gd2O3. Furthermore, the introduction of BaO in relatively large amounts can improve the above-mentioned weather resistance, and SrO and CaO require even larger amounts to improve weather resistance. Therefore, the value calculated as "(3×Al2O3+Y2O3+La2O3+Gd2O3+BaO / 3+(CaO+SrO) / 6)" (unit: mol%) is preferably 0% or more, more preferably greater than 0%, and preferably 0.5% or more, 1.0% or more, 2.0% or more, 3.0% or more, 4.0% or more, 5.0% or more, 6.0% or more, 7.0% or more, and 8.0% or more. Furthermore, when prioritizing the weather resistance and mechanical strength of the glass, the following percentages are preferable in order: 9.0% or more, 10.0% or more, 11.0% or more, 12.0% or more, 13.0% or more, 14.0% or more, 15.0% or more, 16.0% or more, 17.0% or more, 18.0% or more, and 19.0% or more. In "(3×Al2O3+Y2O3+La2O3+Gd2O3+BaO / 3+(CaO+SrO) / 6)", "Al2O3" is the Al2O3 content, "Y2O3" is the Y2O3 content, "La2O3" is the La2O3 content, "Gd2O3" is the Gd2O3 content, "BaO" is the BaO content, "CaO" is the CaO content, and "SrO" is the SrO content. That is, "(3×Al2O3+Y2O3+La2O3+Gd2O3+BaO / 3+(CaO+SrO) / 6)" is the sum of the value calculated by multiplying the Al2O3 content by 3, the values ​​calculated by dividing the Y2O3 content, La2O3 content, Gd2O3 content, and BaO content by 1 / 3, and the value calculated by dividing the sum of the CaO content and SrO content by 1 / 6. The value thus calculated shall be expressed with the unit % (mol%). On the other hand, if the value of "(3×Al2O3+Y2O3+La2O3+Gd2O3+BaO / 3+(CaO+SrO) / 6)" is made too large, the fusion properties of the glass tend to deteriorate, and the position of near-infrared absorption tends to shift towards the visible light side. Therefore, the value calculated as "(3×Al2O3+Y2O3+La2O3+Gd2O3+BaO / 3+(CaO+SrO) / 6)" is preferably 40.0% or less, and is more preferably 37.0% or less, 35.0% or less, 33.0% or less, 32.0% or less, 30.0% or less, 28.0% or less, 26.0% or less, 25.0% or less, 24.0% or less, 23.0% or less, 22.0% or less, and 21.0% or less, in that order.

[0113] The ratio of the value calculated by "(3×Al2O3+Y2O3+La2O3+Gd2O3+BaO / 3+(CaO+SrO) / 6)" to the total content of P2O5, Li2O, and CuO, i.e., "(3×Al2O3+Y2O3+La2O3+Gd2O3+BaO / 3+(CaO+SrO) / 6) / (P2O5+Li2O+CuO)", can be 0.0 or greater. It is desirable that the component selected from the group consisting of Al2O3, Y2O3, La2O3, Gd2O3, BaO, CaO, and SrO be introduced in amounts greater than or equal to the essential components P2O5, Li2O, and CuO. Therefore, the above ratio is preferably 0.01 or higher, and is more preferably 0.02 or higher, 0.03 or higher, 0.04 or higher, 0.05 or higher, 0.06 or higher, 0.07 or higher, 0.08 or higher, and 0.09 or higher, in that order. To further improve weather resistance, the above ratio is even more preferably 0.10 or higher, and is more preferably 0.11 or higher, 0.12 or higher, 0.13 or higher, 0.14 or higher, 0.15 or higher, 0.16 or higher, 0.17 or higher, 0.18 or higher, 0.19 or higher, 0.20 or higher, 0.21 or higher, 0.22 or higher, 0.23 or higher, 0.24 or higher, or 0.25 or higher, in that order. On the other hand, if the above ratio is made too large, the transmittance characteristics of the glass will decrease, and furthermore, the stability of the glass will tend to decrease. Therefore, the above ratio is preferably 0.36 or less, and is more preferably 0.35 or less, 0.34 or less, 0.33 or less, 0.32 or less, 0.31 or less, 0.30 or less, 0.29 or less, and 0.28 or less, in that order.

[0114] The ZnO content can be 0%, 0% or more, or greater than 0%. ZnO is a component that can be added as appropriate for reasons such as adjusting the thermal stability of the glass. However, it tends to reduce the weather resistance of the glass, and from the viewpoint of ensuring a sufficient amount of the essential component P2O5, the upper limit of its content is preferably 20.0% or less, with the following percentages being more preferable: 19.0% or less, 18.0% or less, 17.0% or less, 16.0% or less, 15.0% or less, 14.0% or less, 13.0% or less, 12.0% or less, 11.0% or less, 10.0% or less, 9.0% or less, 8.0% or less, 7.0% or less, 6.0% or less, and 5.0% or less. When prioritizing the effects of other components, the ZnO content can also be 4.0% or less, 3.0% or less, 2.0% or less, or 1.0% or less. On the other hand, when introducing ZnO to adjust the thermal stability of the glass and lower Tg and / or Tm, the amounts are more preferable in the following order: 0.4% or more, 0.6% or more, 0.8% or more, 1.0% or more, 1.2% or more, 1.4% or more, 1.6% or more, 1.8% or more, and 2.0% or more.

[0115] While the above-mentioned glass is preferably composed primarily of the above-mentioned components, it is also possible to include other components as long as they do not interfere with the effects and benefits of the above-mentioned components. Furthermore, this does not exclude the inclusion of unavoidable impurities in the above-mentioned glass.

[0116] For example, Nb2O5 and ZrO2 may be introduced as components other than those mentioned above to adjust the weather resistance, mechanical strength, or thermal stability of the glass, in amounts of more than 0%, 0.1% or more, or 0.2% or more, respectively. However, the content of each component should preferably be 5.0% or less, with the order of preference being 4.0% or less, 3.0% or less, 2.0% or less, 1.0% or less, 0.5% or less, and 0.3% or less. The content of each of these components may also be 0%.

[0117] TiO2, WO3, and Bi2O3 may also be introduced as components other than those mentioned above, in amounts greater than 0%, 0.1% or more, or 0.2% or more, respectively, to adjust the weather resistance, mechanical strength, or thermal stability of the glass, as long as it does not affect the transmittance of the glass. However, the content of each component should preferably be 4.0% or less, with the order of preference being 3.0% or less, 2.0% or less, 1.0% or less, 0.5% or less, and 0.3% or less. The content of each of these components may also be 0%.

[0118] Pb, As, Cd, Tl, Be, and Se are all toxic. Therefore, it is preferable that the above-mentioned glass does not contain these as glass components.

[0119] U, Th, and Ra are all radioactive elements. Therefore, it is preferable that the glass described above does not contain these elements as glass components.

[0120] V, Cr, Mn, Fe, Co, Ni, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, and Tm can increase the coloration of glass and become sources of fluorescence. Therefore, in the above glass, it is preferable that the total amount of these elements on an oxide basis is 10 ppm by mass or less, and it is even more preferable that these elements are not included as glass components.

[0121] In particular, it is preferable not to use V2O5 because it is toxic. Specifically, in one embodiment, it is preferable that glass 1 to 6 are glass that does not contain V ions, and in the oxide-based glass composition (molar basis), the V2O5 content is preferably 1.0% or less, more preferably 0.3% or less, 0.1% or less, and more preferably 0.01% or less, in that order, and it is even more preferable that it does not contain V2O5.

[0122] As an example, the ratio of V2O5 to the essential component Li2O, namely the ratio of V2O5 content to Li2O content (V2O5 / Li2O), is preferably 0.0080 or less, with 0.0048 or less, 0.0028 or less, 0.0018 or less, and 0.0014 or less being the most preferred values.

[0123] CoO is preferable to avoid using it because it reduces the visible light transmittance of the glass and is also toxic. In other words, in one embodiment, glasses 1 to 6 are preferably Co-ion-free glasses, and it is preferable that the oxide-based glass composition does not contain CoO.

[0124] The raw materials for introducing Ge and Ta into glass are expensive. Therefore, it is preferable that the glass described above does not contain these as glass components.

[0125] Sb(Sb2O3), Sn(SnO2), Ce(CeO2), and SO3 are optional additives that function as clarifying agents. Of these, Sb(Sb2O3) is a clarifying agent with a significant clarifying effect. Sn(SnO2) and Ce(CeO2) have a smaller clarifying effect compared to Sb(Sb2O3). Adding large amounts of these clarifying agents tends to increase the discoloration of the glass. Therefore, when adding a clarifying agent, it is preferable to add Sb(Sb2O3) while considering the effect of the added discoloration.

[0126] The content of the components that can function as clarifying agents listed below is given based on the oxide-based glass composition.

[0127] The Sb2O3 content is expressed as an external percentage. That is, when the total content of all glass components other than Sb2O3, SnO2, CeO2, and SO3 as oxides is set to 100.0% by mass, the Sb2O3 content is preferably less than 2.0% by mass, and is more preferably in the order of 1.5% by mass or less, 1.2% by mass or less, 1.0% by mass or less, 0.9% by mass or less, 0.8% by mass or less, 0.7% by mass or less, 0.6% by mass or less, 0.5% by mass or less, 0.4% by mass or less, 0.3% by mass or less, 0.2% by mass or less, and less than 0.1% by mass. The Sb2O3 content may be 0% by mass. However, from the viewpoint of promoting the oxidation of the glass and increasing the transmittance in the visible range, the Sb2O3 content can be 0.01% by mass or more, and can also be 0.02% by mass or more, 0.03% by mass or more, 0.04% by mass or more, 0.05% by mass or more, 0.06% by mass or more, or 0.08% by mass or more.

[0128] The SnO2 content is also expressed as an external percentage. That is, when the total content of all glass components other than SnO2, Sb2O3, CeO2, and SO3 as oxides is set to 100.0% by mass, the SnO2 content is preferably less than 2.0% by mass, more preferably less than 1.0% by mass, more preferably 0.9% by mass or less, 0.8% by mass or less, 0.7% by mass or less, 0.6% by mass or less, 0.5% by mass or less, 0.4% by mass or less, 0.3% by mass or less, 0.2% by mass or less, and more preferably 0.1% by mass. The SnO2 content may be 0% by mass. The clarity of the glass can be improved by setting the SnO2 content within the above range.

[0129] The CeO2 content is also expressed as an external percentage. That is, when the total content of all glass components other than CeO2, Sb2O3, SnO2, and SO3 as oxides is set to 100.0% by mass, the CeO2 content is preferably less than 2.0% by mass, more preferably less than 1.0% by mass, more preferably 0.9% by mass or less, 0.8% by mass or less, 0.7% by mass or less, 0.6% by mass or less, 0.5% by mass or less, 0.4% by mass or less, 0.3% by mass or less, 0.2% by mass or less, and more preferably less than 0.1% by mass. The CeO2 content may also be 0% by mass. The clarity of the glass can be improved by setting the CeO2 content within the above range.

[0130] The SO3 content will also be displayed separately. 3、 When the total content of all glass components other than Sb2O3, SnO2, and CeO2 as oxides is taken as 100.0% by mass, the SO3 content is preferably in the range of less than 2.0% by mass, more preferably less than 1.0% by mass, even more preferably less than 0.5% by mass, and even more preferably less than 0.1% by mass. The SO3 content may also be 0% by mass. By setting the SO3 content within the above range, the clarity of the glass can be improved.

[0131] <Glass Properties> (Transmittance characteristics) The above-mentioned glass is suitable as glass for near-infrared cut filters. In the present invention and this specification, unless otherwise specified, "transmittance" refers to external transmittance including reflection loss. Regarding near-infrared blocking capability, the wavelength at which the transmittance is 50% is the half-maximum (λ) wavelength, which is 550 nm or higher. T A value of 50 can be used as an indicator, the transmittance T1200 at a wavelength of 1200 nm can be used as an indicator, the average value of the transmittance in the range of wavelengths from 1100 nm to 800 nm (indicated as "Ave. T1100-800") can be used as an indicator, and the transmittance T750 at a wavelength of 750 nm can be used as an indicator. Furthermore, the above-mentioned glass can also exhibit high transmittance in the visible range. For transmittance in the visible range, the transmittance T400 at a wavelength of 400 nm can be used as an indicator, and the transmittance T600 at a wavelength of 600 nm can also be used as an indicator.

[0132] The transmittance characteristics of glass are determined by the following method. Glass samples are processed to have parallel and optically polished surfaces, and their external transmittance at wavelengths of 200–1200 nm is measured. The external transmittance includes the reflection loss of light rays at the sample surface. Let intensity A be the intensity of light rays incident perpendicularly on one optically polished plane, and intensity B be the intensity of light rays emitting from the other plane. Calculate the spectral transmittance B / A, including reflection loss. The wavelength at which the spectral transmittance is 50% above 550 nm is defined as λ at half maximum. T Let's assume a value of 50. The spectral transmittance at a wavelength of 400 nm is T400, the spectral transmittance at a wavelength of 600 nm is T600, and the spectral transmittance at a wavelength of 1200 nm is T1200. The average value of the spectral transmittance in the range of wavelengths from 1100 nm to 800 nm is Ave. T1100-800, and the spectral transmittance at a wavelength of 750 nm is T750. Furthermore, if the glass being measured is not of a thickness that can be converted, the thickness of the glass is denoted as d, and the transmittance at each wavelength λ is converted using the following formula A. Various converted values ​​can then be determined from the transmittance characteristics obtained through this conversion.

[0133] Equation A: T(λ)=(1-R(λ)) 2 × exp(log e ((T0(λ) / 100) / (1-R(λ)) 2 ) × d / d0) × 100

[0134] In equation A, T(λ): converted transmittance at wavelength λ (%), T0(λ): measured transmittance at wavelength λ (%), d: converted thickness (mm), d0: glass thickness (mm), R(λ) = ((n(λ)-1) / (n(λ)+1)) 2 The formula is expressed as the reflectance at wavelength λ, where n(λ) is the refractive index at wavelength λ. Here, we will calculate by considering n(λ) = 1.51680 and R(λ) = 0.042165 as constants.

[0135] A high T600 value, which represents transmittance in the red region, and a low T1200 value, which represents transmittance in the near-infrared region, could indicate that both improved transmittance in the visible region and improved near-infrared blocking capabilities have been achieved. Similarly, a high T400 value, which represents transmittance in the violet region, could also indicate improved transmittance in the visible region. From the above perspective, the preferred ranges for T400, T600, and T1200 are as follows: For T400, it is preferably 70% or higher, and more preferably 71% or higher, 72% or higher, 73% or higher, 74% or higher, 75% or higher, 76% or higher, 77% or higher, 78% or higher, 79% or higher, and 80% or higher, in that order. T400 can be, for example, 98% or lower, 97% or lower, or 96% or lower, but it is also preferable to have a T400 higher than the values ​​exemplified above, as a higher T400 means better visible light transmittance. For T600, it is preferable that it be 50% or more, and more preferably in the order of 55% or more, 56%, 57% or more, 58% or more, 59% or more, 60% or more, 61% or more, 62% or more, 63% or more, 64% or more, 65% or more, 66% or more, 67% or more, 68% or more, 69% or more, 70% or more, 71% or more, 72% or more, 73% or more, 74% or more, and 75% or more. T600 can be, for example, 90% or less, 85% or less, or 80% or less, but it is also preferable that it exceeds the values ​​exemplified above, as a higher T600 means better visible light transmittance. For T1200, it is preferably 30% or less, and more preferably 29% or less, 28% or less, 27% or less, 26% or less, 25% or less, 24% or less, 23% or less, 22% or less, 21% or less, 20% or less, 19% or less, 18% or less, 17% or less, 16% or less, 15% or less, 14% or less, 13% or less, 12% or less, 11% or less, 10% or less, 9% or less, 8% or less, 7% or less, 6% or less, 5% or less, 4% or less, 3% or less, 2% or less, and 1% or less. For the purpose of achieving compatibility with visible light transmittance, T1200 can be, for example, 1% or more, 3% or more, 5% or more, or 7% or more, but it is also preferable for T1200 to be lower than the values ​​exemplified above, as a lower T1200 means better near-infrared cut capability.

[0136] In one form, T1200 can have a β content of 1% or less.

[0137] β1 is calculated using the following formula B1. In formula B1, R is the O / P ratio. (Formula B1) β1 = 64 × R - 170

[0138] In one form, T1200 can also be less than or equal to the values ​​shown in β2, β3, β4, β5, and β6 in the following formulas B2 to B6 (unit: %). In the following formulas, R is the O / P ratio. Formula B2:β2=64×R-175 Equation B3: β3 = 64 × R - 180 Formula B4:β4=80×R-220 Formula B5:β5=80×R-224 Formula B6:β6=80×R-228

[0139] λ at half maximum is the wavelength at which the spectral transmittance is 50% above 550 nm. T 50 is preferably 600 nm or higher, and more preferably in the order of 610 nm or higher, 613 nm or higher, 615 nm or higher, 617 nm or higher, 620 nm or higher, 623 nm or higher, 625 nm or higher, and 628 nm or higher. T 50 is preferably 650 nm or less, and more preferably in the order of 647 nm or less, 645 nm or less, 643 nm or less, 641 nm or less, 640 nm or less, 639 nm or less, and 638 nm or less. λ at half maximum is the wavelength at which the spectral transmittance is 50% at wavelengths of 550 nm or more. T Achieving a value of 50 with a glass thickness below a predetermined level is preferable from the viewpoint of balancing thinning the glass with improving near-infrared cutting ability. The glass thickness below a predetermined level is preferably 0.25 mm or less.

[0140] Furthermore, since the above glass has excellent absorption characteristics in the near-infrared region, the "Ave. T1100-800" can be kept below 15%. The "Ave. T1100-800" is preferably 14% or less, and is more preferably 13% or less, 12% or less, 11% or less, 10% or less, 9% or less, 8% or less, 7% or less, 6% or less, 5% or less, 4% or less, 3% or less, 2% or less, 1.3% or less, 1.0% or less, 0.3% or less, 0.1% or less, 0.03% or less, and 0.01% or less, in that order.

[0141] Furthermore, since the above glass has excellent absorption characteristics in the near-infrared region, the T750 can be kept below 25%. The T750 is preferably 24% or less, and is more preferably 23% or less, 22% or less, 21% or less, 20% or less, 19% or less, 18% or less, 17% or less, 16% or less, 15% or less, 14% or less, 13% or less, 12% or less, 11% or less, 10% or less, 9% or less, 8% or less, 7% or less, 6% or less, 5% or less, 4% or less, 3% or less, 2% or less, 1.3% or less, 1.0% or less, 0.3% or less, 0.1% or less, 0.03% or less, and 0.01% or less, in that order.

[0142] As will be described in detail later, the above glass can, in one form, be used as a near-infrared cut filter glass with a thickness of 0.25 mm or less.

[0143] Regarding the above glass, the following (a) to (h) are desirable transmittance characteristics for a thinned near-infrared cut filter glass with a thickness of 0.25 mm or less. The above glass preferably satisfies one or more of the following (a) to (h), and may also satisfy two or more. By performing the glass composition adjustment described above, glass with desirable transmittance characteristics can be obtained.

[0144] (a) wavelength λ at which the external transmittance including reflection loss is 50% at wavelengths of 550 nm or higher T The glass thickness at which 50 corresponds to 633nm is 0.25mm or less. At the above thickness, the external transmittance T600, including reflection loss at a wavelength of 600 nm, is 50% or more, and the external transmittance T1200, including reflection loss at a wavelength of 1200 nm, is 30% or less.

[0145] Regarding (a) above, the wavelength λ at which the external transmittance including reflection loss is 50% at wavelengths of 550 nm or higher is... TThe glass thickness at which 50 corresponds to 633 nm is 0.25 mm or less, and it is more preferable that the thickness of the near-infrared cut filter falls within the thickness range described later. This also applies to (b), (e), and (f) below.

[0146] (b) The thickness of the glass is 0.25 mm or less such that the wavelength at which the external transmittance including reflection loss is 50% at wavelengths of 550 nm or higher is 633 nm. At the above thickness, the external transmittance T600, including reflection loss at a wavelength of 600 nm, is 50% or more, and the external transmittance T1200, including reflection loss at a wavelength of 1200 nm, is β1% or less. β is a value calculated from the following formula B1. In formula B1, R is the O / P ratio of the above glass.

[0147] (Formula B1) β1 = 64 × R - 170

[0148] As mentioned earlier, T1200 can also have β2% or less, β3% or less, β4% or less, β5% or less, or β6% or less.

[0149] (c) The wavelength λ at which the external transmittance, including reflection loss, is 50% as a transmittance characteristic calculated for a thickness of 0.11 mm. T The value 50 is in the range of 600nm to 650nm, the external transmittance T1200 including reflection loss at a wavelength of 1200nm is 30% or less, and the external transmittance T400 including reflection loss at a wavelength of 400nm is 70% or more.

[0150] (d) The wavelength λ at which the external transmittance, including reflection loss, is 50% as a transmittance characteristic calculated on a thickness of 0.21 mm. T The value 50 is in the range of 600nm to 650nm, the external transmittance T1200 including reflection loss at a wavelength of 1200nm is 25% or less, and the external transmittance T400 including reflection loss at a wavelength of 400nm is 70% or more.

[0151] (e) The thickness of the glass is 0.25 mm or less such that the wavelength at which the external transmittance including reflection loss is 50% at wavelengths of 550 nm or higher is 645 nm. At the above thickness, the external transmittance T600, including reflection loss at a wavelength of 600 nm, is 50% or more, and the external transmittance T1200, including reflection loss at a wavelength of 1200 nm, is 30% or less.

[0152] (f) The wavelength λ at which the external transmittance, including reflection loss, is 50% at wavelengths of 550 nm or higher T The glass thickness at which 50 corresponds to 645nm is 0.25mm or less. At the above thickness, the external transmittance T600, including reflection loss at a wavelength of 600 nm, is 50% or more, and the external transmittance T1200, including reflection loss at a wavelength of 1200 nm, is β1% or less, where β1 is the value calculated by Equation 4 described above.

[0153] (g) The wavelength λ at which the external transmittance, including reflection loss, is 50% is calculated as the transmittance characteristic for a thickness of 0.23 mm. T The value 50 is in the range of 600nm to 650nm, the external transmittance T1200 including reflection loss at a wavelength of 1200nm is 18% or less, and the external transmittance T400 including reflection loss at a wavelength of 400nm is 70% or more.

[0154] (h) The wavelength λ at which the external transmittance, including reflection loss, is 50% is calculated as the transmittance characteristic for a thickness of 0.25 mm. T The value 50 is in the range of 600nm to 650nm, the external transmittance T1200 including reflection loss at a wavelength of 1200nm is 16% or less, and the external transmittance T400 including reflection loss at a wavelength of 400nm is 70% or more.

[0155] (weather resistance) The above glass, having the composition described above, can exhibit excellent weather resistance. Regarding weather resistance, for example, the weather resistance evaluation result obtained by visual inspection using the method described in the examples below can be used as an indicator, and such evaluation result is preferably one of S to D, more preferably one of S to C, even more preferably one of S to B, even more preferably S or A, and even more preferably S. Furthermore, weather resistance can also be indicated by the haze value measured by a haze meter. Glass with an even higher haze value of 15% or less can be cited as having superior weather resistance. Regarding weather resistance, it is even more preferable that the evaluation result obtained by visual inspection is S or A (preferably S), and that the haze value measured by a haze meter is 15% or less.

[0156] (Glass transition temperature Tg, temperature Tm at which the endothermic reaction due to melting converges) The glass transition temperature of the above glass is not particularly limited, but from the viewpoint of improving the transmittance of the glass in the short wavelength range by improving the meltability of the glass, and from the viewpoint of reducing the burden on the annealing furnace and molding equipment, the Tg is preferably 450°C or lower, and more preferably in the order of 440°C or lower, 430°C or lower, 420°C or lower, 410°C or lower, and 400°C or lower. From the viewpoint of improving the chemical durability and / or heat resistance of the glass, the Tg is preferably 250°C or higher, and more preferably in the order of 260°C or higher, 270°C or higher, 280°C or higher, 290°C or higher, and 300°C or higher.

[0157] The Tg value of glass can be controlled by adjusting the content and total content of Li2O, Na2O, K2O, ZnO, MgO, Al2O3, and their respective components.

[0158] The temperature Tm at which the endothermic reaction due to the melting of the glass converges is not particularly limited, but the lower the Tm, the better the meltability, and the less likely devitrification is to occur in the glass even when molding with higher viscosity. Furthermore, the better the meltability, the more likely it is to be possible to increase the transmittance of the glass in the visible range in the short wavelength region. From these viewpoints, Tm is preferably 890°C or lower, and more preferably in the order of 880°C or lower, 870°C or lower, 860°C or lower, 850°C or lower, 840°C or lower, 830°C or lower, 820°C or lower, 810°C or lower, 800°C or lower, 790°C or lower, 780°C or lower, 770°C or lower, 760°C or lower, 750°C or lower, 740°C or lower, 730°C or lower, 720°C or lower, 710°C or lower, 700°C or lower, 690°C or lower, 680°C or lower, 670°C or lower, 660°C or lower, and 650°C or lower. While there is no particular lower limit to Tm, if Tm is too low, the weather resistance of the glass tends to decrease. Therefore, Tm can also be 500°C or higher, 550°C or higher, 580°C or higher, 600°C or higher, 620°C or higher, or 640°C or higher.

[0159] The Tm value of glass can be controlled by adjusting the content and total content of Li2O, Na2O, K2O, ZnO, MgO, Al2O3, and their combined content.

[0160] (specific gravity) A lightweight near-infrared cut filter is preferable because it contributes to the weight reduction of the elements and devices into which the filter is incorporated. From this perspective, the specific gravity of the glass is preferably 3.40 or less, and more preferably in the following order: 3.35 or less, 3.30 or less, 3.25 or less, 3.20 or less, 3.15 or less, 3.10 or less, 3.05 or less, 3.00 or less, 2.95 or less, 2.90 or less, 2.85 or less, 2.80 or less, 2.75 or less, 2.70 or less, 2.65 or less, and 2.60 or less. The specific gravity can be, for example, 2.0 or higher or 2.4 or higher, but from the above viewpoint, a lower specific gravity is preferable, so it is also preferable that it be lower than the values ​​exemplified here.

[0161] (Molar volume) The molar volume M / D of the glass is not particularly limited, but from the viewpoint of enhancing near-infrared absorption ability by increasing the amount of CuO per unit volume, a smaller molar volume of the glass is preferable. The molar volume can be decreased when P₂O₅, La₂O₃, Y₂O₃, Gd₂O₃, BaO, K₂O, etc. are substituted for Li₂O, and can be slightly decreased when Al₂O₃, CuO or Na₂O is substituted for Li₂O. On the other hand, even when CaO, ZnO or SrO is substituted for Li₂O, the molar volume does not change significantly, and when MgO is substituted for Li₂O, the molar volume tends to increase. The molar volume of the glass can be adjusted by adjusting the glass composition in consideration of these tendencies. The molar volume is preferably 45 cc / mol or less, and is more preferable in the order of 43 cc / mol or less, 42 cc / mol or less, 41 cc / mol or less, 40 cc / mol or less, 39.5 cc / mol or less, 39.0 cc / mol or less, 38.5 cc / mol or less, 38.0 cc / mol or less, and 37.5 cc / mol or less. On the other hand, from the viewpoint of maintaining the weather resistance of the glass, the molar volume can be increased. From this point of view, the molar volume of the glass can be 34.0 cc / mol or more, and can also be 35.0 cc / mol or more, 36.0 cc / mol or more, 36.5 cc / mol or more, 37.0 cc / mol or more, 37.5 cc / mol or more, 38.0 cc / mol or more, 38.5 cc / mol or more, 39.0 cc / mol or more, or 39.5 cc / mol or more.

[0162] <Method for Producing Glass> The above glass can be obtained by mixing, melting and molding various glass raw materials. For the production method, reference can also be made to the description below.

[0163] The above near-infrared absorbing glass is suitable as glass for near-infrared cut filters. In addition, the above near-infrared absorbing glass can also be applied to optical elements (such as lenses) other than near-infrared cut filters, and can also be applied to various other glass products, and various modifications are also possible.

[0164] [Near-infrared Cut Filter] One aspect of the present invention relates to a near-infrared cut filter made of the above near-infrared absorbing glass (hereinafter, also simply referred to as "filter").

[0165] The glass constituting the above filter is as described above.

[0166] Specific examples of the method for producing the above filter will be described below. However, the following production method is an example and does not limit the present invention.

[0167] For the molten glass, glass raw materials such as phosphates, oxides, carbonates, nitrates, sulfates, and fluorides are appropriately used, the raw materials are weighed to obtain a desired composition and mixed, and then melted, for example, at 800°C to 1100°C in a melting vessel such as a platinum crucible. In this case, a lid made of platinum or the like may be used to suppress volatilization of volatile components. Further, melting can be performed in the atmosphere, and in order to suppress a change in the valence of Cu, an oxygen atmosphere may be used, or oxygen may be bubbled into the molten glass. Through stirring and clarification, the molten glass becomes a homogenized molten glass with reduced bubbles (preferably containing no bubbles). Alternatively, after clarifying the glass at 900°C to 1100°C, the glass may be cooled to 800°C to 1000°C to promote oxidation of the glass, and then the glass may be obtained. However, it is not desirable that the melting temperature or the clarification temperature be lower than the liquidus temperature of the glass for a long time.

[0168] After stirring and clarifying the molten glass, the glass is poured out, gradually cooled, and then formed into a desired shape. When pouring out the glass, it is preferable to lower the temperature to around the liquidus temperature to increase the viscosity of the glass before pouring, because this makes convection less likely to occur in the poured glass and less likely to cause striae. As the slow cooling rate, a rate between -50°C / hr and -1°C / hr can be selected, and -30°C / hr or -10°C / hr can also be selected.

[0169] Known methods such as casting, pipe pouring, rolling, and pressing can be used for forming the glass. The formed glass is transferred to an annealing furnace that has been preheated to near the transition point of the glass, and slowly cooled to room temperature. In this way, a near-infrared cut filter can be manufactured.

[0170] An example of a molding method is described below. A mold is prepared, consisting of a flat, horizontal bottom surface, a pair of side walls parallel to each other and flanking the bottom surface, and a weir plate that closes one of the openings located between the pair of side walls. Molten glass, homogenized from a platinum alloy pipe, is poured into this mold at a constant flow rate. The poured molten glass spreads within the mold and is formed into a glass plate of a certain width, restricted by the pair of side walls. The formed glass plate is continuously pulled out from the opening of the mold. By appropriately setting the molding conditions such as the shape and dimensions of the mold and the flow rate of the molten glass, large and thick glass blocks can be formed. The formed glass body is transferred to an annealing furnace that has been preheated to near the glass transition temperature and slowly cooled to room temperature. The glass body, whose distortion has been removed by slow cooling, is subjected to machining such as slicing, grinding, and polishing. In this way, near-infrared cut filters in shapes such as plates and lenses, depending on the application, can be obtained. Alternatively, a method can be used in which a preform made of the above-mentioned glass is formed, and this preform is heated, softened, and then press-formed (especially a precision press-forming method that press-forms the final product without performing machining such as grinding or polishing on the optical functional surface). An optical multilayer film may be formed on the surface of the filter as needed.

[0171] The above-mentioned near-infrared cut filter combines excellent near-infrared cutting capability with high transmittance in the visible range. Such a near-infrared cut filter allows for effective color sensitivity correction of semiconductor image sensors.

[0172] Furthermore, the above-mentioned near-infrared cut filter can be applied to an imaging device by combining it with a semiconductor image sensor. A semiconductor image sensor has a semiconductor image element such as a CCD or CMOS mounted inside a package, and the light-receiving part is covered with a light-transmitting material. The light-transmitting material can also be used as the near-infrared cut filter, or the light-transmitting material can be a separate component from the near-infrared cut filter.

[0173] The above imaging device may also include an optical element such as a lens or prism for forming an image of the subject on the light-receiving surface of the semiconductor image sensor.

[0174] Furthermore, the above-mentioned near-infrared cut filter enables good color sensitivity correction, making it possible to provide an imaging device capable of obtaining images with excellent image quality.

[0175] The above-mentioned near-infrared cut filter can, in one embodiment, be a near-infrared cut filter with a thickness of 0.25 mm or less. In recent years, with the advent of smartphones, there has been a noticeable trend towards reducing the thickness of image sensors in cameras, and accordingly, there is a demand for near-infrared cut filters that can perform well with a thinner thickness. The above-mentioned near-infrared cut filter is suitable as such a near-infrared cut filter. The thickness of the above-mentioned near-infrared cut filter can be 0.24 mm or less, 0.23 mm or less, 0.22 mm or less, 0.21 mm or less, 0.20 mm or less, 0.19 mm or less, 0.18 mm or less, 0.17 mm or less, 0.16 mm or less, 0.15 mm or less, 0.14 mm or less, 0.13 mm or less, or 0.12 mm or less. The thickness of the above-mentioned near-infrared cut filter can be, for example, 0.21 mm or 0.11 mm. Furthermore, the thickness of the above-mentioned near-infrared cut filter can be, for example, 0.50 mm or more, but is not limited to this. In the present invention and this specification, "thickness" refers to the thickness of the sample in the area where transmittance is to be measured, and can be measured using a thickness gauge, micrometer, or the like. For example, the thickness may be measured at approximately the center of the position through which the transmitted light passes, or the thickness may be measured at multiple points within the spot of transmitted light and the average value may be taken.

[0176] For the transmittance characteristics of the above near-infrared cut filter, please refer to the previous description regarding glass 1 to 6. Similarly, for the physical properties of the above near-infrared cut filter, please refer to the previous description regarding glass 1 to 6. [Examples]

[0177] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the embodiments described herein.

[0178] [Examples 1-66, Comparative Examples X, A-D] As glass raw materials, phosphates, fluorides, carbonates, nitrates, oxides and the like were weighed and mixed such that 150 g to 300 g of glass having the composition shown in Table 1 was obtained, then put into a platinum crucible or a quartz crucible, melted at 800°C to 1000°C for 80 minutes to 100 minutes, stirred for defoaming and homogenization, then poured into a preheated mold and molded into a predetermined shape. The obtained glass molded body was transferred to an annealing furnace heated to near the glass transition temperature, and slowly cooled to room temperature. A test piece was cut out from the obtained glass, both surfaces were mirror-polished to a thickness of about 0.2 mm, and then various evaluations were performed by the following methods.

[0179] [Evaluation Method] <Transmittance Characteristics> The transmittance of each test piece at a wavelength of 200 to 1200 nm was measured using a spectrophotometer. From the measurement results, half-width (unit: nm), T400, T600, T1200, and Ave.T1100-800 (unit: %) were obtained as values converted to half-width 645 nm, half-width 633 nm, thickness 0.11 mm, thickness 0.21 mm, thickness 0.23 mm, and thickness 0.25 mm, respectively.

[0180] <Glass Transition Temperature Tg, Temperature Tm at Which Endothermic Reaction Due to Melting Converges> Using a differential scanning calorimeter (DSC8270) manufactured by Rigaku, the glass transition temperature Tg and the temperature Tm at which the endothermic reaction due to melting converges were measured at a temperature increase rate of 10°C / min. The measurement temperature range was from room temperature to 1050°C.

[0181] <Specific Gravity> Specific gravity was measured by the Archimedean method.

[0182] <Molar Volume> Molar volume was calculated from the measured specific gravity value by the method described above.

[0183] <Weather Resistance Evaluation Classification> Each test piece was kept in a constant temperature and humidity chamber at 85°C and 85% relative humidity for 3.5 hours. Afterward, each test piece was subjected to a visual inspection under fluorescent lighting. Based on the evaluation results, weather resistance was assessed according to the following criteria. S: Surface clouding and / or precipitates are very mild. A: Surface clouding and / or precipitates are minor. B: A moderate level of clouding is observed on the surface, and / or precipitates are present. C: Surface wetting indicating deliquescence is observed, but is mild, and / or thick precipitates are present. D: Deliquescence is present to a degree that does not result in a significant reduction in plate thickness, and / or precipitates covering the plain glass have formed. E: Deliquescence has occurred to such an extent that a clear reduction in plate thickness is observed, and / or precipitates have formed to the point where the plain glass is no longer visible.

[0184] [Table 1-1]

[0185] [Table 1-2]

[0186] [Table 1-3]

[0187] [Table 2-1]

[0188] [Table 2-2]

[0189] [Table 2-3]

[0190] Table 3-1

[0191] Table 3-2

[0192] Table 3-3

[0193] Table 4-1

[0194] Table 4-2

[0195] Table 4-3

[0196] Table 5-1

[0197] Table 5-2

[0198] Table 5-3

[0199] Table 6-1

[0200] [Table 6-2]

[0201] [Table 6-3]

[0202] [Table 7-1]

[0203] [Table 7-2]

[0204] [Table 7-3]

[0205] From the results shown in the table above, it can be confirmed that the glass of Examples 1 to 66 exhibits high transmittance in the visible range (purple to red regions) even when thinned, has excellent near-infrared blocking ability, and suppresses the deterioration of weather resistance. Regarding weather resistance, a comparison between Examples 1-58 and Example 59 confirms that Examples 1-58 have better weather resistance than Example 59, where the value calculated as "(3×Al2O3+Y2O3+La2O3+Gd2O3+BaO / 3+(CaO+SrO) / 6)" is 0, while Examples 1-58 have a larger value for this calculation. In comparison with Example 59, Example 60, in which the value calculated as "(3×Al2O3+Y2O3+La2O3+Gd2O3+BaO / 3+(CaO+SrO) / 6)" is 0 and the value of "(Na2O+K2O+ZnO) / Li2O" is greater than 1.4 compared to Example 59, exhibits a greater degree of deliquescence and is slightly inferior in terms of weather resistance compared to Example 59. Comparative Example X has a value greater than 0 when calculated as "(3×Al2O3+Y2O3+La2O3+Gd2O3+BaO / 3+(CaO+SrO) / 6)", but the value of "(Na2O+K2O+ZnO) / Li2O" is large, exceeding 11, indicating low weather resistance. Comparative Examples A, B, and C are glasses composed of only three components: P2O5, Li2O, and CuO, and exhibit extremely low weather resistance. Comparative Example D had an O / P ratio exceeding 3.2, and the desired transmittance characteristics could not be obtained.

[0206] In the examples where the visual weather resistance evaluation described above resulted in an evaluation category of S or A, the haze value was also determined using a haze meter for Examples 25, 33, 56, and 61-66. The determined haze values ​​are shown in Table 8.

[0207] [Table 8]

[0208] As shown in Table 8, the haze values ​​of Examples 56, 61-66, and 66, which received an evaluation of S in the visual weather resistance evaluation, were lower than those of Examples 25 and 33, which received an evaluation of A in the visual weather resistance evaluation, and were 15% or less.

[0209] From the above results, it can be confirmed that in order to achieve both improved visible light transmittance and improved near-infrared cut capability, and further reduce the haze value to 15% or less, it is preferable that the O / P ratio is in the range of 3.00 to 3.15, and that the value calculated as "(3×Al2O3+Y2O3+La2O3+Gd2O3+BaO / 3+(CaO+SrO) / 6)" (unit: mole%) is in the range of 10.0% to 40.0%.

[0210] Finally, we will summarize each of the aforementioned aspects.

[0211] According to one embodiment, the glasses 1 to 6 described in detail above are provided.

[0212] In one embodiment, the Al2O3 content in glass 1-6 can be less than 2.0 mol%.

[0213] In one embodiment, the total content of Al2O3, La2O3, Y2O3, and Gd2O3 (Al2O3 + La2O3 + Y2O3 + Gd2O3) in glass 1 to 6 can be 0.1 mol% or more.

[0214] In one embodiment, the glasses 1 to 6 can have the following transmittance characteristics.

[0215] λ at half maximum is the wavelength at which the external transmittance, including reflection loss, is 50% above 550 nm. T The glass thickness at which 50 corresponds to 633nm is 0.25mm or less. At the above thickness, the external transmittance T600, including reflection loss at a wavelength of 600 nm, is 50% or more, and the external transmittance T1200, including reflection loss at a wavelength of 1200 nm, is 30% or less.

[0216] λ at half maximum is the wavelength at which the external transmittance, including reflection loss, is 50% above 550 nm. T The glass thickness at which 50 corresponds to 633nm is 0.25mm or less. At the above thickness, the external transmittance T600, including reflection loss at a wavelength of 600 nm, is 50% or more, and the external transmittance T1200, including reflection loss at a wavelength of 1200 nm, is β1% or less. β1 is given by the following equation B1: (Formula B1) β1 = 64 × R - 170 This is a value calculated by, In the above formula B1, R is the above ratio (O ions / P ions).

[0217] The transmittance characteristic calculated for a thickness of 0.11 mm is the wavelength at which the external transmittance, including reflection loss, is 50% (half-maximum latitude). TThe value 50 is in the range of 600nm to 650nm, the external transmittance T1200 including reflection loss at a wavelength of 1200nm is 30% or less, and the external transmittance T400 including reflection loss at a wavelength of 400nm is 70% or more.

[0218] The transmittance characteristic calculated for a thickness of 0.21 mm is the wavelength at which the external transmittance, including reflection loss, is 50% (half-maximum latitude). T The value 50 is in the range of 600nm to 650nm, the external transmittance T1200 including reflection loss at a wavelength of 1200nm is 25% or less, and the external transmittance T400 including reflection loss at a wavelength of 400nm is 70% or more.

[0219] λ at half maximum is the wavelength at which the external transmittance, including reflection loss, is 50% above 550 nm. T The glass thickness at which 50 corresponds to 645nm is 0.25mm or less. At the above thickness, the external transmittance T600, including reflection loss at a wavelength of 600 nm, is 50% or more, and the external transmittance T1200, including reflection loss at a wavelength of 1200 nm, is 30% or less.

[0220] λ at half maximum is the wavelength at which the external transmittance, including reflection loss, is 50% above 550 nm. T The glass thickness at which 50 corresponds to 645nm is 0.25mm or less. At the above thickness, the external transmittance T600, including reflection loss at a wavelength of 600 nm, is 50% or more, and the external transmittance T1200, including reflection loss at a wavelength of 1200 nm, is β1% or less. The above β1 is given by the following equation B1: (Formula B1) β1 = 64 × R - 170 This is a value calculated by, In the above formula B1, R is the above ratio (O ions / P ions).

[0221] According to one embodiment, a near-infrared cut filter made of the above-mentioned near-infrared absorbing glass is provided.

[0222] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the claims rather than the foregoing description, and all modifications within the meaning and scope of equivalents of the claims are intended. For example, by performing the compositional adjustments described in the specification on the glass composition exemplified above, a near-infrared absorbing glass according to one aspect of the present invention can be obtained. Furthermore, it is certainly possible to arbitrarily combine two or more items that are described as examples or preferred scopes in the specification.

Claims

1. It contains four or more major cations selected from the group consisting of P ions, Li ions, Cu ions, Al ions, Ba ions, Sr ions, Ca ions, Mg ions, Zn ions, K ions, Na ions, La ions, Gd ions, and Y ions. It contains P ions, Li ions, and Cu ions as essential cations. It contains at least an O ion as an anion, The ratio of O ions to P ions (O ions / P ions) is 3.15 or less. In the glass composition expressed in anion percentage, the O ion content is 90.0 anion% or more. In terms of moles, The total content of oxides of the aforementioned major cations is 90.0% or more. The total content of P₂O₅, Li₂O, and CuO (P₂O₅ + Li₂O + CuO) is 50.0% or more. The total content of MgO and Al₂O₃ (MgO + Al₂O₃) is 8.0% or less. The ratio of the total content of Na₂O, K₂O, and ZnO to the Li₂O content ((Na₂O + K₂O + ZnO) / Li₂O) is 2.4 or less. The total content of B₂O₃ and SiO₂ (B₂O₃ + SiO₂) is 3.0% or less. Near-infrared absorbing glass having an external transmittance T400 of 70% or more, including reflection loss at a wavelength of 400 nm, as a transmittance characteristic calculated for a thickness of 0.21 mm, and an external transmittance T1200 of 10% or less, including reflection loss at a wavelength of 1200 nm, as a transmittance characteristic calculated for a thickness of 0.21 mm.

2. Formula 2 below: (Formula 2) C-3200×exp(-2.278×R)≧0 Satisfying the conditions, In the above equation 2, C is the CuO content per molar volume of glass (unit: millimoles / cc), R is the aforementioned ratio (O ions / P ions). The near-infrared absorbing glass according to claim 1.

3. Formula 3 below: (Formula 3) A １ ={O(P)-O(others)}×Cu A calculated by １ The number is 2500 or more, In the above formula 3, O(P) indicates the amount of oxygen that constitutes the oxide of P ions in the oxide-based glass composition. O(others) represents the amount of oxygen obtained by subtracting O(P) from the amount of oxygen constituting the oxide of the main cation in the oxide-based glass composition. Cu represents the molar CuO content in the oxide-based glass composition. The near-infrared absorbing glass according to claim 1.

4. Formula 4 below: (Formula 4) A ２ ={O(P)-O(others)}×C A calculated by ２ The number is 700 or more, In the above formula 4, C is the CuO content per molar volume of glass (unit: millimoles / cc), O(P) indicates the amount of oxygen that constitutes the oxide of P ions in the oxide-based glass composition. O(others) represents the amount of oxygen obtained by subtracting O(P) from the amount of oxygen constituting the oxide of the main cation in the oxide-based glass composition. The near-infrared absorbing glass according to claim 1.

5. CuO content is α ２ It is % or more, α² is given by the following equation 5: (Formula 5) a ２ = 76522×exp(-2.855×R) This is a value calculated by, In the above formula 5, R is the aforementioned ratio (O ions / P ions). The near-infrared absorbing glass according to claim 1.

6. Formula 6 below: (Formula 6) C-3478×exp(-2.278×R)≧0 Satisfying the conditions, In the aforementioned formula 6, C is the CuO content per molar volume of glass (unit: millimoles / cc), R is the aforementioned ratio (O ions / P ions). The near-infrared absorbing glass according to claim 1.

7. It contains four or more major cations selected from the group consisting of P ions, Li ions, Cu ions, Al ions, Ba ions, Sr ions, Ca ions, Mg ions, Zn ions, K ions, Na ions, La ions, Gd ions, and Y ions. It contains P ions, Li ions, and Cu ions as essential cations. It contains at least an O ion as an anion, The ratio of O ions to P ions (O ions / P ions) is 3.15 or less. In the glass composition expressed in anion percentage, the O ion content is 90.0 anion% or more. In oxide-based glass composition, In terms of moles, The total content of oxides of the aforementioned major cations is 90.0% or more. The total content of P₂O₅, Li₂O, and CuO (P₂O₅ + Li₂O + CuO) is 50.0% or more. MgO and Al ２ O ３ total content (MgO+Al ２ O ３ ) is 8.0% or less, Li ２ Na in relation to O content ２ O content, K ２ The ratio of the total O content and ZnO content ((Na ２ O+K ２ O+ZnO) / Li ２ O) is 2.4 or less, B ２ O ３ and SiO ２ Total content (B ２ O ３ +SiO ２ ) is 3.0% or less, CuO content is α １ It is % or more, α １ The formula is as follows: (Formula 1) a １ = 70400×exp(-2.855×R) This is a value calculated by, In the above formula 1, R is the aforementioned ratio (O ions / P ions), Near-infrared absorbing glass having transmittance characteristics calculated for a thickness of 0.21 mm, where the external transmittance T1200, including reflection loss at a wavelength of 1200 nm, is 10% or less, and the external transmittance T400, including reflection loss at a wavelength of 400 nm, is 70% or more.

8. It contains four or more major cations selected from the group consisting of P ions, Li ions, Cu ions, Al ions, Ba ions, Sr ions, Ca ions, Mg ions, Zn ions, K ions, Na ions, La ions, Gd ions, and Y ions. It contains P ions, Li ions, and Cu ions as essential cations. It contains at least an O ion as an anion, The ratio of O ions to P ions (O ions / P ions) is 3.15 or less. In the glass composition expressed in anion percentage, the O ion content is 90.0 anion% or more. In oxide-based glass composition, In terms of moles, The total content of oxides of the aforementioned major cations is 90.0% or more. The total content of P₂O₅, Li₂O, and CuO (P₂O₅ + Li₂O + CuO) is 50.0% or more. MgO and Al ２ O ３ Total content (MgO + Al ２ O ３ ) is 8.0% or less, Li ２ Na in relation to O content ２ O content, K ２ The ratio of the total O content and ZnO content ((Na ２ O+K ２ O+ZnO) / Li ２ O) is 2.4 or less, B ２ O ３ and SiO ２ Total content (B ２ O ３ +SiO ２ ) is 3.0% or less, Formula 2 below: (Formula 2) C-3200×exp(-2.278×R)≧0 Satisfying the conditions, In the above equation 2, C is the CuO content per molar volume of glass (unit: millimoles / cc), R is the aforementioned ratio (O ions / P ions), Near-infrared absorbing glass having transmittance characteristics calculated for a thickness of 0.21 mm, where the external transmittance T1200, including reflection loss at a wavelength of 1200 nm, is 10% or less, and the external transmittance T400, including reflection loss at a wavelength of 400 nm, is 70% or more.

9. It contains four or more major cations selected from the group consisting of P ions, Li ions, Cu ions, Al ions, Ba ions, Sr ions, Ca ions, Mg ions, Zn ions, K ions, Na ions, La ions, Gd ions, Y ions, B ions, and Si ions. It contains P ions, Li ions, and Cu ions as essential cations. It contains at least an O ion as an anion, The ratio of O ions to P ions (O ions / P ions) is 3.15 or less. In the glass composition expressed in anion percentage, the O ion content is 90.0 anion% or more. In oxide-based glass composition, In terms of moles, The total content of oxides of the aforementioned major cations is 90.0% or more. The total content of P₂O₅, Li₂O, and CuO (P₂O₅ + Li₂O + CuO) is 50.0% or more. MgO and Al ２ O ３ Total content (MgO + Al ２ O ３ ) is 8.0% or less, Li ２ Na in relation to O content ２ O content, K ２ The ratio of the total O content and ZnO content ((Na ２ O+K ２ O+ZnO) / Li ２ O) is 2.4 or less, The total content of B₂O₃ and SiO₂ (B₂O₃ + SiO₂) is 3.0% or less. Formula 3 below: (Formula 3) A １ ={O(P)-O(others)}×Cu A calculated by １ The number is 2500 or more, In the above formula 3, O(P) indicates the amount of oxygen that constitutes the oxide of P ions in the oxide-based glass composition. O(others) represents the amount of oxygen obtained by subtracting O(P) from the amount of oxygen constituting the oxide of the main cation in the oxide-based glass composition. Cu represents the molar CuO content in the oxide-based glass composition. Near-infrared absorbing glass having transmittance characteristics calculated for a thickness of 0.21 mm, where the external transmittance T1200, including reflection loss at a wavelength of 1200 nm, is 10% or less, and the external transmittance T400, including reflection loss at a wavelength of 400 nm, is 70% or more.

10. It contains four or more major cations selected from the group consisting of P ions, Li ions, Cu ions, Al ions, Ba ions, Sr ions, Ca ions, Mg ions, Zn ions, K ions, Na ions, La ions, Gd ions, Y ions, B ions, and Si ions. It contains P ions, Li ions, and Cu ions as essential cations. It contains at least an O ion as an anion, The ratio of O ions to P ions (O ions / P ions) is 3.15 or less. In the glass composition expressed in anion percentage, the O ion content is 90.0 anion% or more. In oxide-based glass composition, In terms of moles, The total content of oxides of the aforementioned major cations is 90.0% or more. The total content of P₂O₅, Li₂O, and CuO (P₂O₅ + Li₂O + CuO) is 50.0% or more. MgO and Al ２ O ３ Total content (MgO + Al ２ O ３ ) is 8.0% or less, Li ２ Na in relation to O content ２ O content, K ２ The ratio of the total O content and ZnO content ((Na ２ O+K ２ O+ZnO) / Li ２ O) is 2.4 or less, The total content of B₂O₃ and SiO₂ (B₂O₃ + SiO₂) is 3.0% or less. Formula 4 below: (Formula 4) A ２ ={O(P)-O(others)}×C A calculated by ２ The number is 700 or more, In the above formula 4, C is the CuO content per molar volume of glass (unit: millimoles / cc), O(P) indicates the amount of oxygen that constitutes the oxide of P ions in the oxide-based glass composition. O(others) represents the amount of oxygen obtained by subtracting O(P) from the amount of oxygen constituting the oxide of the main cation in the oxide-based glass composition. Near-infrared absorbing glass having transmittance characteristics calculated for a thickness of 0.21 mm, where the external transmittance T1200, including reflection loss at a wavelength of 1200 nm, is 10% or less, and the external transmittance T400, including reflection loss at a wavelength of 400 nm, is 70% or more.

11. It contains four or more major cations selected from the group consisting of P ions, Li ions, Cu ions, Al ions, Ba ions, Sr ions, Ca ions, Mg ions, Zn ions, K ions, Na ions, La ions, Gd ions, and Y ions. It contains P ions, Li ions, and Cu ions as essential cations. It contains at least an O ion as an anion, The ratio of O ions to P ions (O ions / P ions) is 3.15 or less. In the glass composition expressed in anion percentage, the O ion content is 90.0 anion% or more. In oxide-based glass composition, In terms of moles, The total content of oxides of the aforementioned major cations is 90.0% or more. The total content of P₂O₅, Li₂O, and CuO (P₂O₅ + Li₂O + CuO) is 50.0% or more. MgO and Al ２ O ３ Total content (MgO + Al ２ O ３ ) is 8.0% or less, Li ２ Na in relation to O content ２ O content, K ２ The ratio of the total O content and ZnO content ((Na ２ O+K ２ O+ZnO) / Li ２ O) is 2.4 or less, The total content of B₂O₃ and SiO₂ (B₂O₃ + SiO₂) is 3.0% or less. CuO content is α ２ It is % or more, α ２ The formula is as follows: 5: (Formula 5) a ２ = 76522×exp(-2.855×R) This is a value calculated by, In the above formula 5, R is the aforementioned ratio (O ions / P ions), Near-infrared absorbing glass having transmittance characteristics calculated for a thickness of 0.21 mm, where the external transmittance T1200, including reflection loss at a wavelength of 1200 nm, is 10% or less, and the external transmittance T400, including reflection loss at a wavelength of 400 nm, is 70% or more.

12. It contains four or more major cations selected from the group consisting of P ions, Li ions, Cu ions, Al ions, Ba ions, Sr ions, Ca ions, Mg ions, Zn ions, K ions, Na ions, La ions, Gd ions, and Y ions. It contains P ions, Li ions, and Cu ions as essential cations. It contains at least an O ion as an anion, The ratio of O ions to P ions (O ions / P ions) is 3.15 or less. In the glass composition expressed in anion percentage, the O ion content is 90.0 anion% or more. In oxide-based glass composition, In terms of moles, The total content of oxides of the aforementioned major cations is 90.0% or more. The total content of P₂O₅, Li₂O, and CuO (P₂O₅ + Li₂O + CuO) is 50.0% or more. MgO and Al ２ O ３ Total content (MgO + Al ２ O ３ ) is 8.0% or less, Li ２ Na in relation to O content ２ O content, K ２ The ratio of the total O content and ZnO content ((Na ２ O+K2O+ZnO) / Li ２ O) is 2.4 or less, The total content of B₂O₃ and SiO₂ (B₂O₃ + SiO₂) is 3.0% or less. Formula 6 below: (Formula 6) C-3478×exp(-2.278×R)≧0 Satisfying the conditions, In the aforementioned formula 6, C is the CuO content per molar volume of glass (unit: millimoles / cc), R is the aforementioned ratio (O ions / P ions), Near-infrared absorbing glass having transmittance characteristics calculated for a thickness of 0.21 mm, where the external transmittance T1200, including reflection loss at a wavelength of 1200 nm, is 10% or less, and the external transmittance T400, including reflection loss at a wavelength of 400 nm, is 70% or more.

13. Na ２ O content and K ２ The near-infrared absorbing glass according to any one of claims 1 to 12, wherein the total content with respect to oxygen is less than 15.0 mol%.

14. Al ２ O ３ The near-infrared absorbing glass according to any one of claims 1 to 13, wherein the content is less than 2.0 mol%.

15. Al ２ O ３ and La ２ O ３ and Y ２ O ３ and Gd ２ O ３ the total content (Al ２ O ３ + La ２ O ３ + Y ２ O ３ + Gd ２ O ３ ) is 0.1 mol% or more, the near-infrared absorbing glass according to any one of claims 1 to 14.

16. The glass thickness is 0.25 mm or less, such that the half-maximum λT50 (the wavelength at which the external transmittance including reflection loss is 50% at wavelengths of 550 nm or higher) is 633 nm. The near-infrared absorbing glass according to any one of claims 1 to 15, wherein, at the aforementioned thickness, the external transmittance T600 including reflection loss at a wavelength of 600 nm is 50% or more, and the external transmittance T1200 including reflection loss at a wavelength of 1200 nm is 30% or less.

17. The glass thickness is 0.25 mm or less, such that the half-maximum λT50 (the wavelength at which the external transmittance including reflection loss is 50% at wavelengths of 550 nm or higher) is 633 nm. At the aforementioned thickness, the external transmittance T600, including the reflection loss at a wavelength of 600 nm, is 50% or more, and the external transmittance T1200, including the reflection loss at a wavelength of 1200 nm, is β １ It is less than %. β １ The following formula B1: (Formula B1) b １ =64×R-170 This is a value calculated by, In the above formula B1, The near-infrared absorbing glass according to any one of claims 1 to 16, wherein R is the ratio (O ions / P ions).

18. The near-infrared absorbing glass according to any one of claims 1 to 17, wherein, as a transmittance characteristic calculated on a thickness of 0.11 mm, the half-maximum λT50, which is the wavelength at which the external transmittance including reflection loss is 50%, is in the range of 600 nm to 650 nm, the external transmittance T1200 including reflection loss at a wavelength of 1200 nm is 30% or less, and the external transmittance T400 including reflection loss at a wavelength of 400 nm is 70% or more.

19. The near-infrared absorbing glass according to any one of claims 1 to 18, wherein, as a transmittance characteristic calculated on a thickness of 0.21 mm, the half-maximum λT50, which is the wavelength at which the external transmittance including reflection loss is 50%, is in the range of 600 nm to 650 nm.

20. The glass thickness is 0.25 mm or less, such that the half-maximum λT50 (the wavelength at which the external transmittance including reflection loss is 50% at wavelengths of 550 nm or higher) is 645 nm. The near-infrared absorbing glass according to any one of claims 1 to 19, wherein, at the aforementioned thickness, the external transmittance T600 including reflection loss at a wavelength of 600 nm is 50% or more, and the external transmittance T1200 including reflection loss at a wavelength of 1200 nm is 30% or less.

21. The glass thickness is 0.25 mm or less, such that the half-maximum λT50 (the wavelength at which the external transmittance including reflection loss is 50% at wavelengths of 550 nm or higher) is 645 nm. At the aforementioned thickness, the external transmittance T600, including the reflection loss at a wavelength of 600 nm, is 50% or more, and the external transmittance T1200, including the reflection loss at a wavelength of 1200 nm, is β １ It is less than %. Said β １ The following formula B1: (Formula B1) b １ =64×R-170 This is a value calculated by, In the above formula B1, The near-infrared absorbing glass according to any one of claims 1 to 20, wherein R is the ratio (O ions / P ions).

22. A near-infrared cut filter made of near-infrared absorbing glass according to any one of claims 1 to 21.

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