Near-infrared absorbing glass and near infrared blocking filter

Abstract

To provide a near-infrared absorbing glass having excellent near-infrared blocking capability, high visible light transmittance and excellent weather resistance and a near-infrared blocking filter composed of the glass.SOLUTION: There is provided a near-infrared absorbing glass in which in the glass composition represented by cation percentage, the content of Cu ions is 15.0% or less, the content of P ions is 55.0% or less, the cation ratio ((Al ions+P ions) / (Mg ions+Ca ions+Sr ions+Ba ions+Zn ions+Cu ions)) is 5.300 or less, the cation ratio ((Mg ions+Ca ions+Sr ions+Ba ions) / (Li ions+Na ions+K ions)) is 0.100 or more, and the average valence of cations other than Cu ions and P ions is less than 1.500, and in the glass composition represented by anion percentage, the content of O ions is 85.0% or more and the ratio of the content of O ions to the content of P ions is 3.300 or more.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to near-infrared absorbing glass and a near-infrared cut filter.

Background Art

[0002] A near-infrared cut filter has a function of cutting unnecessary near-infrared light (wavelength 700 to 1200 nm) in the sensitivity wavelength range of an image sensor in order to make the light entering the image sensor such as a CCD or a CMOS have a light wavelength distribution corresponding to the human relative visual sensitivity curve. The near-infrared cut filter is generally often provided immediately before the image sensor.

[0003] The near-infrared cut filter is widely used with a near-infrared absorbing glass as a base material and polished on a flat plate.

[0004] Near-infrared absorbing glass generally contains Cu ions. An example of the spectral transmittance characteristics of near-infrared absorbing glass is shown in FIG. 1. Note that FIG. 1 does not limit the present invention in any way. The light absorption characteristics in the vicinity of a wavelength of 700 to 1200 nm are exhibited by Cu ions (Cu 2+ ) in the glass. Among them, phosphate glass containing Cu ions can exhibit the near-infrared absorption characteristics of Cu ions (Cu 2+ ) in a wide wavelength range, and thus is useful as glass for a near-infrared cut filter (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] In the transmittance curve of Figure 1 with wavelengths of 600 nm and above, the wavelength at which the transmittance becomes 50% is called the "half-value", which is one of the main specifications of the near-infrared cut filter. The half-value varies depending on the filter specifications, but is often set in the range of 600 nm to 650 nm. As a general method for setting the half-value to a desired value, according to the Lambert-Beer law, there is a method of adjusting either the plate thickness of the glass substrate or the concentration of Cu ions (Cu 2+ ) in the glass.

Summary of the Invention

Problems to be Solved by the Invention

[0007] Near-infrared cut filters are required to have excellent near-infrared cutting ability (i.e., low transmittance of near-infrared light while having a desired half-value) and high transmittance of visible light (wavelengths 400 to 600 nm).

[0008] In recent years, image sensor modules mounted on smartphones and the like are required to achieve both miniaturization and high performance. Therefore, the plate thickness of near-infrared cut filters is required to be reduced. In order to reduce the thickness while maintaining the near-infrared cutting ability, it is necessary to increase the concentration of Cu ions (Cu 2+ ) in the glass. However, if the ratio of the Cu component in the glass raw material is simply increased for this purpose, Cu 2+ is reduced during melting, and the resulting Cu + increases, and it is known that the transmittance particularly near 400 nm decreases.

[0009] Furthermore, in order to maintain transmittance characteristics under various usage environments, near-infrared cut filters are desired to have high chemical durability (i.e., excellent weather resistance) under high-temperature and high-humidity environments.

[0010] In view of the above, an aspect of the present invention aims to provide a near-infrared absorbing glass having excellent near-infrared cutting ability, high visible light transmittance, and excellent weather resistance, and a near-infrared cut filter made of such near-infrared absorbing glass.

Means for Solving the Problem

[0011] In order to increase the visible light transmittance, the inventors of the present invention examined the glass composition from the following two viewpoints. (1) A glass composition that can obtain a desired half-value and sufficient near-infrared cut-off ability even with a smaller amount of Cu compared to the conventional one. (2) In order to suppress the generation of Cu + during melting, since it is effective to melt and form the glass at a lower temperature, a glass composition having better meltability of the raw material batch than the conventional one.

[0012] Regarding (1), the inventors of the present invention assumed a complex glass skeleton in which P2O5 is arranged around Cu 2+ , and by reducing the average valence of monovalent and divalent ions, which are intermediate components other than these glass skeletons, the inflow of electrons into Cu 2+ , that is, the generation of Cu + can be suppressed, and at the same time, it was found that the light absorption wavelength region of Cu 2+ shifts to a shorter wavelength, and the amount of Cu required to achieve the desired half-value can be reduced.

[0013] Regarding (2), the inventors of the present invention found that by making the proportion of glass network-forming components such as Al and P below a certain level, the meltability of the glass raw material batch can be improved, and it becomes possible to melt and form at a lower temperature than the conventional one.

[0014] Furthermore, the inventors of the present invention also found that by making the ratio of O to P in the whole glass equal to or more than a certain level, the amount of Cu required to achieve the desired half-value can be reduced, and furthermore, it becomes possible to suppress the formation of P-O-P cross-linking bonds that are inferior in water resistance and improve the weather resistance.

[0015] That is, one aspect of the present invention is As constituent ions, P ions, Cu ions, O ions, At least one ion selected from the group consisting of Li ions, Na ions, and K ions, and At least one ion selected from the group consisting of Mg ions, Ca ions, Sr ions, and Ba ions, including at least In the glass composition expressed in cation %, the content of Cu ions is 15.0 cation % or less, the content of P ions is 55.0 cation % or less, the cation ratio of the total content of Al ions and P ions to the total content of Mg ions, Ca ions, Sr ions, Ba ions, Zn ions, and Cu ions ((Al ions + P ions) / (Mg ions + Ca ions + Sr ions + Ba ions + Zn ions + Cu ions)) is 5.300 or less, the cation ratio of the total content of Mg ions, Ca ions, Sr ions, and Ba ions to the total content of Li ions, Na ions, and K ions ((Mg ions + Ca ions + Sr ions + Ba ions) / (Li ions + Na ions + K ions)) is 0.100 or more, the average valence number of cations excluding Cu ions and P ions is less than 1.500, In the glass composition expressed in anion %, the content of O ions is 85.0 anion % or more, and the ratio of the content of O ions to the content of P ions (O ions / P ions) is 3.300 or more, a near-infrared absorbing glass. (Hereinafter, also simply referred to as "glass"). relates to.

[0016] By having the above glass composition, the above near-infrared absorbing glass can have excellent near-infrared cut ability, high visible light transmittance, and excellent weather resistance and meltability.

Effects of the Invention

[0017] According to one aspect of the present invention, it is possible to provide a near-infrared absorbing glass that is excellent in near-infrared cut ability, has a high visible light transmittance, and is excellent in weather resistance and meltability. Further, according to one aspect of the present invention, it is possible to provide a near-infrared cut filter made of such a near-infrared absorbing glass.

Brief Description of the Drawings

[0018]

Figure 1

Embodiments for Carrying Out the Invention

[0019] [Near-Infrared Absorbing Glass] In the present invention and this specification, the near-infrared absorbing glass is a glass having a property of absorbing light in at least the entire region or a part of the wavelength range of the near-infrared wavelength region (wavelength 700 to 1200 nm). Further, the near-infrared absorbing glass according to one aspect of the present invention can be an oxide glass because it contains O ions (oxygen ions) as constituent ions. An oxide glass is a glass in which the main network-forming component of the glass is an oxide. Furthermore, the near-infrared absorbing glass according to one aspect of the present invention can be a phosphate glass because it contains P ions (phosphorus ions) together with O ions (oxygen ions) as constituent ions.

[0020] Hereinafter, the above near-infrared absorbing glass will be described in more detail.

[0021] <Glass Composition> In the present invention and this specification, the content and total content of cations (cation components) are expressed in cation% unless otherwise specified, and the content and total content of anions (anion components) are expressed in anion% unless otherwise specified. Here, "cation%" is a value calculated by "(number of cations of interest / total number of cations of glass components) × 100", and means the molar percentage of the amount of cations of interest with respect to the total amount of cations. The "anion %" is a value calculated by "(the number of anions of interest / the total number of anions in the glass components) × 100", and means the mole percentage of the amount of anions of interest relative to the total amount of anions. The molar ratio of the contents of cations to each other is equal to the ratio of the contents in terms of cation % of the cations of interest, and the molar ratio of the contents of anions to each other is equal to the ratio of the contents in terms of anion % of the anions of interest. The molar ratio of the content of cations to the content of anions is the ratio of the contents (in mole %) of the components of interest when the total amount of all cations and all anions is taken as 100 mol%. The content of each component can be determined by a known method, for example, inductively coupled plasma atomic emission spectrometry (ICP - AES), inductively coupled plasma mass spectrometry (ICP - MS), ion chromatography, etc., to quantify the content ratio (mass % of the element) of the elements contained in the glass. By dividing this content ratio (mass % of the element) by the atomic weight, the content of each element in mole % can be obtained, and from this value, the cation % and anion % can be obtained. Also, in the present invention and in this specification, when the content of a constituent component is 0% or not contained or not introduced, it means that this constituent component is substantially not contained, and it is allowed that this constituent component is contained at an inevitable impurity level. The inevitable impurity level means, for example, less than 0.01%.

[0022] Regarding the valence of cations, in order to obtain the average valence described in detail later, the formal valence of each cation is used. The formal valence is the valence required for the oxide of the cation of interest to maintain electrical neutrality when the valence of the oxygen ions (anions) constituting the oxide is set to - 2, and can be uniquely determined from the chemical formula of the oxide. For example, for Cu ions, in the chemical formula of the oxide CuO, the valence of Cu is +2 in order to maintain electrical neutrality with O 2- and Cu. Also, for example, for P ions, in the chemical formula of the oxide P2O5, the valence of P is +5 in order to maintain electrical neutrality with O 2- and P. Generalizing this, for cation AX O Y The formal valence of O is “+2X / Y”. Therefore, when analyzing the glass composition, it is not necessary to analyze the valence of cations. Also, regarding the valence of anions (for example, the valence of oxygen ions is -2), it is a formal valence based on the idea that oxygen ions accept two electrons and take a closed-shell structure. Therefore, when analyzing the glass composition, it is not necessary to analyze the valence of anions. Also, as described above, part of Cu 2+ can become Cu + during melting, but since the amount is small, the valence of Cu can all be regarded as +2 when calculating the average valence without any problem.

[0023] (Cations) P ions are glass network-forming components. From the viewpoints of improving weather resistance and melting properties, the P ion content in the above glass is 55.0% or less, preferably 53.0% or less, more preferably 51.0% or less, still more preferably 50.0% or less, even more preferably 49.0% or less, yet even more preferably 48.0% or less, still even more preferably 47.0% or less, still yet even more preferably 46.0% or less, still yet even more preferably 45.0% or less, still yet even more preferably 44.0% or less. Since the above glass contains P ions as constituent ions, the P ion content is more than 0%. From the viewpoints of improving devitrification resistance during glass melting and improving the mechanical strength of the glass, the P ion content is preferably 30.0% or more, more preferably 32.0% or more, still more preferably 34.0% or more, even more preferably 36.0% or more, yet even more preferably 38.0% or more, still even more preferably 39.0% or more, still yet even more preferably 40.0% or more, still yet even more preferably 41.0% or more. The formal valence of P ions is +5.

[0024] Cu ions are components that contribute to providing near-infrared cut-off ability to the glass. From the perspective of enhancing visible light transmittance, the Cu ion content of the above glass is 15.0% or less, preferably 13.0% or less, more preferably 11.0% or less, and even more preferably 9.0% or less. Since the above glass contains Cu ions as constituent ions, the Cu ion content is more than 0%. In order to have sufficient near-infrared cut-off ability, the Cu ion content is preferably 0.5% or more, more preferably 1.5% or more, and even more preferably 2.5% or more. As will be described in detail later, in one form, the above glass can be used as a near-infrared cut-off filter glass with a thickness of 0.25 mm or less. Among the above thickness ranges, for a glass suitable for a near-infrared cut-off filter with a relatively thin thickness (hereinafter, also referred to as "Glass I"), the Cu ion content is preferably 1.5% or more, and more preferably 1.7% or more, 1.9% or more, 2.1% or more, 2.3% or more, 2.5% or more, 2.7% or more, 2.9% or more, 3.1% or more, 3.3% or more, 3.5% or more, 3.7% or more, 3.9% or more, 4.1% or more, 4.5% or more, 4.7% or more, 4.9% or more, 5.1% or more in this order. Also, from the perspective of further enhancing the visible light transmittance in such a near-infrared cut-off filter, the Cu ion content of Glass I is preferably 15.0% or less, and more preferably 13.0% or less, 11.0% or less, 10.0% or less, 9.0% or less, 8.5% or less, 8.0% or less, 7.5% or less, 7.0% or less, 6.5% or less, 6.0% or less in this order. By multiplying the above preferred range by (0.11 / d), the preferred value of the Cu ions to be contained in the glass suitable for a near-infrared cut-off filter having a desired thickness can be obtained. d is the thickness for which the preferred value of the Cu ions is desired, and the unit is mm. Also, for glass suitable for a near-infrared cut filter having a relatively thick thickness within the range of 0.25 mm or less (hereinafter, also referred to as "glass II"), in one embodiment, the preferable range of Cu ions can be obtained by multiplying the above preferable range by (0.11 / d). Also, for glass II, in one embodiment, the Cu ion content is preferably 0.5% or more, more preferably 0.7% or more, 0.9% or more, 1.1% or more, 1.3% or more, 1.5% or more, 1.7% or more, 1.9% or more, 2.1% or more, 2.3% or more, 2.5% or more in this order. Further, from the viewpoint of further increasing the visible light transmittance in such a near-infrared cut filter, in one embodiment, the Cu ion content of glass II is preferably 10.0% or less, more preferably 9.0% or less, 8.5% or less, 8.0% or less, 7.5% or less, 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 in this order. The formal valence of Cu ions is +2.

[0025] The Li ion content of the above glass can be 0%, 0% or more, or more than 0%. Li ions are components that function to improve the devitrification resistance during the melting and forming of the glass. From the perspective of enhancing the meltability of the glass, the Li ion content is preferably 10.0% or more, more preferably 12.0% or more, still more preferably 13.0% or more, even more preferably 14.0% or more, yet more preferably 15.0% or more, still more preferably 16.0% or more, even more preferably 17.0% or more, yet more preferably 18.0% or more, still more preferably 20.0% or more, yet more preferably 20.5% or more, still more preferably 21.0% or more, even more preferably 21.5% or more, 22.0% or more, 22.5% or more, 23.0% or more, 23.5% or more, 24.0% or more, 24.5% or more, 25.0% or more, 25.5% or more, 26.0% or more in that order. Also, from the perspective of improving the chemical durability and / or processability of the glass, or increasing the liquid-phase viscosity of the glass, the Li ion content is preferably 32.0% or less, more preferably 31.0% or less, still more preferably 30.5% or less, even more preferably 30.0% or less, yet more preferably 29.5% or less, still more preferably 29.0% or less, even more preferably 28.5% or less, yet more preferably 28.0% or less, and particularly preferably 27.5% or less. The formal valence of Li ions is +1. In one form, from the above perspective, it is preferable that "Li ion content > Na ion content" and "Li ion content > K ion content".

[0026] The Na ion content of the above glass can be 0%, 0% or more, or more than 0%. Na ions are also components that have the function of improving the meltability of the glass. In one form, it is preferable to mainly use Li or K. Specifically, from the viewpoints of improving the devitrification resistance of the glass, improving the viscosity at the liquidus temperature, and improving the chemical durability and / or processability, the Na ion content is preferably 30.0% or less, more preferably 28.0% or less, still more preferably 27.0% or less, even more preferably 25.0% or less, still even more preferably 23.0% or less, still even more preferably 21.0% or less, still even more preferably 19.0% or less, still even more preferably 17.0% or less, still even more preferably 15.0% or less, still even more preferably 13.0% or less, still even more preferably 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, 0.5 or less in this order. The formal valence of Na ions is +1. In one form, from the above viewpoints, it is preferable that "Na ion content < Li ion content", and it is preferable that "Na ion content < K ion content".

[0027] The K ion content of the above glass can be 0%, 0% or more, or more than 0%. K ions are also components that improve the meltability of the glass and further improve the devitrification resistance during melting and forming. From these viewpoints, the K ion content is preferably 3.0% or more, more preferably 4.0% or more, still more preferably 5.0% or more, even more preferably 6.0% or more, even still more preferably 7.0% or more, even yet more preferably 8.0% or more, even still yet more preferably 9.0% or more, and most preferably 10.0% or more. On the other hand, from the viewpoints of improving the viscosity at the liquidus temperature of the glass, improving chemical durability and / or processability, the K ion content is preferably 20.0% or less, more preferably 19.0% or less, still more preferably 17.0% or less, even more preferably 15.0% or less, even still more preferably 14.5% or less, even yet more preferably 14.0% or less, even still yet more preferably 13.5% or less, even yet still more preferably 13.0% or less, and particularly preferably 12.3% or less. The formal valence of K ions is +1. In one form, from the above viewpoints, it is preferable that "K ion content < Li ion content" and it is preferable that "K ion content > Na ion content".

[0028] The above glass contains, as constituent ions, one or more ions selected from the group consisting of Li ions, Na ions and K ions. That is, in one form, the above glass can contain only Li ions, in another form it can contain only Na ions, in another form it can contain only K ions, in another form it can contain Li ions and Na ions, in another form it can contain Li ions and K ions, in another form it can contain Na ions and K ions, and in still another form it can contain Li ions, Na ions and K ions.

[0029] The above glass may also contain other alkali metal ions other than Li ions, Na ions and K ions. Examples of other alkali metal ions include Cs ions. The Cs ion content of the above glass can be 0%, 0% or more, or more than 0%. The formal valence of Cs ions is +1.

[0030] From the viewpoint of reducing the average valence and increasing the visible light transmittance, the total content of Li ions, Na ions and K ions is preferably 19.0% or more, more preferably 21.0% or more, still more preferably 23.0% or more, even more preferably 25.0% or more, still more preferably 27.0% or more, still more preferably 28.0% or more, still more preferably 29.0% or more, still more preferably 30.0% or more, still more preferably 30.5% or more, still more preferably 31.0% or more, and further preferably 32.0% or more, 32.5% or more, 33.0% or more, 33.5% or more, 34.0% or more, 34.5% or more, 35.0% or more, 35.5% or more, 36.0% or more, 36.5% or more, 37.0% or more, 37.5% or more, 38.0% or more, 38.5% or more, 39.0% or more, 39.1% or more in this order. Also, from the viewpoint of further improving the weather resistance, suppressing the decrease in the glass transition temperature and / or suppressing the decrease in the viscosity at the liquidus temperature, the total content of Li ions, Na ions and K ions is preferably 56.0% or less, more preferably 54.0% or less, still more preferably 52.0% or less, even more preferably 50.0% or less, still more preferably 48.0% or less, still more preferably 46.0% or less, still more preferably 45.0% or less, still more preferably 44.0% 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, 40.0% or less, 39.5% or less in this order, which is even more preferable.

[0031] The Mg ion content of the above glass can be 0%, 0% or more, or more than 0%. From the viewpoints of suppressing the decrease in the liquid-phase viscosity of the glass, reinforcing the mechanical strength of the glass, and / or reinforcing the chemical resistance, the Mg ion content is preferably 0.3% or more, more preferably 0.5% or more, still more preferably 0.8% or more, even more preferably 1.1% or more, and yet even more preferably 1.3% or more. Further, from the viewpoint of further improving the devitrification resistance during melting and forming, the Mg ion content is preferably 7.0% or less, more preferably 6.0% or less, still more preferably 5.0% or less, even more preferably 4.0% or less, yet even more preferably 3.5% or less, still even more preferably 3.0% or less, yet even more preferably 2.5% or less, still even more preferably 2.0% or less, and yet even more preferably 1.8% or less. The formal valence of Mg ions is +2. In one form, from the above viewpoints, it is preferable that "Mg ion content < Ca ion content", and it is preferable that "Mg ion content < Ba ion content".

[0032] The Ca ion content of the above glass can be 0%, 0% or more, or more than 0%. From the viewpoints of suppressing the decrease in the liquid-phase viscosity of the glass, reinforcing the mechanical strength of the glass, and reinforcing the chemical resistance, the Ca ion content is preferably 1.3% or more, more preferably 1.5% or more, still more preferably 1.7% or more, even more preferably 1.9% or more, yet even more preferably 2.1% or more, still even more preferably 2.3% or more, still even more preferably 2.5% or more, still even more preferably 2.7% or more, and particularly preferably 2.7% or more. Further, from the viewpoint of further improving the devitrification resistance during melting and forming, the Ca ion content is preferably 9.0% or less, more preferably 8.0% or less, still more preferably 7.0% or less, even more preferably 6.0% or less, yet even more preferably 5.0% or less, still even more preferably 4.5% or less, still even more preferably 4.2% or less, yet even more preferably 3.9% or less, still even more preferably 3.7% or less, and particularly preferably 3.5% or less. The formal valence of the Ca ion is +2. In one form, from the above viewpoints, it is preferable that "Ca ion content > Mg ion content" and it is preferable that "Ca ion content > Sr ion content".

[0033] The Sr ion content of the above glass can be 0%, 0% or more, or more than 0%. From the viewpoints of suppressing the decrease in the liquid-phase viscosity of the glass, reinforcing the mechanical strength of the glass, and reinforcing the chemical resistance, the Sr ion content is preferably 0.2% or more, more preferably 0.4% or more, still more preferably 0.6% or more, even more preferably 0.8% or more, and yet more preferably 0.9% or more. Further, from the viewpoint of further improving the devitrification resistance during melting and forming, the Sr ion content is preferably 4.0% or less, more preferably 3.5% or less, still more preferably 3.3% or less, even more preferably 3.1% or less, yet more preferably 2.7% or less, still more preferably 2.5% or less, even more preferably 2.3% or less, yet even more preferably 2.1% or less, still even more preferably 1.9% or less, yet still even more preferably 1.7% or less, and particularly preferably 1.5% or less. The formal valence of the Sr ion is +2. In one form, from the above viewpoints, it is preferable that "Sr ion content < Ca ion content", and it is preferable that "Sr ion content < Ba ion content".

[0034] The Ba ion content of the above glass can be 0%, 0% or more, or more than 0%. From the viewpoints of suppressing the decrease in the liquid-phase viscosity of the glass, reinforcing the mechanical strength of the glass, and reinforcing the chemical resistance, the Ba ion content is preferably 1.5% or more, more preferably 2.5% or more, still more preferably 2.9% or more, even more preferably 3.1% or more, yet more preferably 3.3% or more, and even more preferably 3.5% or more. Further, from the viewpoint of further improving the devitrification resistance during melting and forming, the Ba ion content is preferably 10.0% or less, more preferably 9.5% or less, still more preferably 9.0% or less, even more preferably 8.5% or less, yet more preferably 8.0% or less, still more preferably 7.5% or less, even more preferably 7.0% or less, yet more preferably 6.5% or less, still more preferably 6.0% or less, yet more preferably 5.6% or less, still more preferably 5.3% or less, and even more preferably 5.0% or less, 4.7% or less, 4.5% or less, 4.3% or less in this order. The formal valence of the Ba ion is +2. In one form, from the above viewpoints, it is preferable that "Ba ion content > Ca ion content" and it is preferable that "Ba ion content > Sr ion content".

[0035] The above glass contains one or more ions selected from the group consisting of Mg ions, Ca ions, Sr ions and Ba ions. From the viewpoint of reducing the average valence and increasing the visible light transmittance, it is preferable that the total content of Mg ions, Ca ions, Sr ions and Ba ions is small. The total content of Mg ions, Ca ions, Sr ions, and Ba ions is preferably 20.0% or less, more preferably 19.0% or less, still more preferably 18.0% or less, even more preferably 17.5% or less, yet more preferably 17.0% or less, still more preferably 16.5% or less, even more preferably 16.0% or less, still more preferably 15.5% or less, yet more preferably 15.0% or less, still more preferably 14.5% or less, even more preferably 14.0% or less, and even more preferably 13.5% or less, 13.0% or less, 12.5% or less, 12.0% or less, 11.0% or less, 10.5% or less, 10.0% or less in this order from the above viewpoints and from the viewpoint of further improving the solubility. Further, the total content of Mg ions, Ca ions, Sr ions, and Ba ions is preferably 3.0% or more, more preferably 4.0% or more, still more preferably 4.5% or more, even more preferably 5.0% or more, yet more preferably 5.5% or more, still more preferably 6.0% or more, even more preferably 6.5% or more, still more preferably 7.0% or more, yet more preferably 7.5% or more, and even more preferably 8.0% or more, 8.5% or more, 9.0% or more in this order from the viewpoints of suppressing the decrease in the liquidus temperature and improving the weather resistance.

[0036] From the perspective of suppressing the decrease in viscosity at the liquidus temperature, improving mechanical strength, and / or suppressing the decrease in glass transition temperature, the cation ratio of the total content of Mg ions, Ca ions, Sr ions, and Ba ions to the total content of Li ions, Na ions, and K ions ((Mg ions + Ca ions + Sr ions + Ba ions) / (Li ions + Na ions + K ions)) is 0.100 or more, preferably 0.105 or more, more preferably 0.110 or more, still more preferably 0.115 or more, even more preferably 0.120 or more, even more preferably 0.125 or more, still even more preferably 0.130 or more, and even more preferably 0.160 or more, 0.180 or more, 0.200 or more, 0.220 or more in that order. Suppressing the decrease in viscosity at the liquidus temperature is preferable from the perspective of improving the formability of the glass. Further, from the perspective of further improving the meltability and / or visible light transmittance, the above cation ratio ((Mg ions + Ca ions + Sr ions + Ba ions) / (Li ions + Na ions + K ions)) is preferably 0.650 or less, more preferably 0.620 or less, still more preferably 0.590 or less, even more preferably 0.560 or less, even more preferably 0.530 or less, still even more preferably 0.500 or less, even more preferably 0.460 or less, still even more preferably 0.430 or less, even more preferably 0.400 or less, even more preferably 0.370 or less, and even more preferably 0.350 or less, 0.320 or less, 0.310 or less, 0.300 or less, 0.295 or less, 0.290 or less, 0.287 or less, 0.285 or less in that order. In addition, since the melting temperature of the glass increases, Cu+ is likely to be generated and the visible light transmittance decreases. Therefore, it is preferable that the above cation ratio be within the above range.

[0037] The Al ion content of the above glass can be 0%, 0% or more, or more than 0%. From the viewpoints of suppressing the decrease in Tg, improving mechanical strength, and improving weather resistance, the Al ion content is preferably 1.0% or more, more preferably 1.3% or more, still more preferably 1.5% or more, even more preferably 1.7% or more, yet more preferably 1.9% or more, still more preferably 2.1% or more, even more preferably 2.3% or more, yet more preferably 2.5% or more, and still more preferably 2.5% or more. Further, from the viewpoint of further enhancing the meltability of the raw materials and suppressing the generation of Cu + From the viewpoint of further suppressing the generation of + , the Al ion content is preferably 8.0% or less, more preferably 7.0% or less, still more preferably 6.5% or less, even more preferably 6.0% or less, yet more preferably 5.5% or less, still more preferably 5.3% or less, even more preferably 5.0% or less, yet more preferably 4.7% or less, still more preferably 4.5% or less, and more preferably 4.0% or less, 2.5% or less, 2.0% or less. The formal valence of Al ions is +3. From the viewpoint of reducing the average valence and increasing the visible light transmittance, it is also preferable that the Al ion content is low.

[0038] The total content of Al ions and P ions (Al ions + P ions) in the above glass is preferably 40.0% or more, more preferably 41.0% or more, still more preferably 42.0% or more, even more preferably 42.5% or more, yet more preferably 43.0% or more, still more preferably 44.0% or more, even more preferably 44.5% or more, yet more preferably 45.0% or more, from the viewpoints of enhancing the thermal stability and mechanical strength of the glass. Further, from the viewpoint of further enhancing the meltability of the raw materials and suppressing the generation of Cu +From the perspective of further suppressing the generation, the total content (Al ions + P ions) is preferably 55.0% or less, more preferably 54.0% or less, still more preferably 53.0% or less, even more preferably 52.0% or less, yet more preferably 51.0% or less, still more preferably 50.0% or less, still even more preferably 49.5% or less, yet even more preferably 49.0% or less, still even more preferably 48.5% or less, still yet even more preferably 48.0% or less, and further preferably 47.0% or less, 46.5% or less, 46.2% or less, 46.0% or less.

[0039] The Zn ion content of the glass can be 0%, 0% or more, or more than 0%. From the perspective of reducing the Tg of the glass, the Zn ion content can be introduced in place of the above-mentioned Mg and / or Ca and / or Sr and / or Ba within a range that does not significantly affect the effects exerted by various components. However, from the perspective of improving weather resistance, the Zn ion content is preferably 8.7% or less, more preferably 8.5% or less, still more preferably 8.3% or less, even more preferably 8.0% or less, yet more preferably 7.7% or less, still more preferably 7.5% or less, still even more preferably 7.3% or less, yet even more preferably 7.1% or less, still even more preferably 6.5% or less, still yet even more preferably 6.0% or less, and further preferably 5.5% or less, 5.0% or less, 4.0% or less, 3.0% or less, 2.0% or less, 1.0% or less in this order. The formal valence of Zn ions is +2.

[0040] From the viewpoint of improving weather resistance, the cation ratio of Zn ions to the total content of Mg ions, Ca ions, Sr ions, Ba ions, and Zn ions (Zn ions / (Mg ions + Ca ions + Sr ions + Ba ions + Zn ions)) is preferably 0.600 or less, more preferably 0.580 or less, still more preferably 0.570 or less, even more preferably 0.560 or less, and further preferably 0.550 or less, 0.540 or less, 0.530 or less, 0.520 or less, 0.510 or less, 0.505 or less, 0.500 or less, 0.498 or less, 0.496 or less, 0.400 or less, 0.300 or less, 0.200 or less, 0.100 or less, 0.080 or less, 0.060 or less, 0.040 or less, 0.020 or less in this order. Also, the cation ratio (Zn ions / (Mg ions + Ca ions + Sr ions + Ba ions + Zn ions)) may be 0 or 0.000.

[0041] From the viewpoint of enhancing the meltability of the raw materials and suppressing the generation of Cu + the cation ratio of the total content of Al ions and P ions to the total content of Mg ions, Ca ions, Sr ions, Ba ions, Zn ions, and Cu ions ((Al ions + P ions) / (Mg ions + Ca ions + Sr ions + Ba ions + Zn ions + Cu ions)) is 5.3 or less. It is preferably 5.1 or less, more preferably 4.9 or less, still more preferably 4.7 or less, even more preferably 4.5 or less, and further preferably 4.3 or less, 4.1 or less, 3.9 or less, 3.7 or less, 3.5 or less, 3.3 or less, 3.1 or less in this order. Also, from the viewpoints of improving the thermal stability and mechanical strength of the glass, the cation ratio ((Al ions + P ions) / (Mg ions + Ca ions + Sr ions + Ba ions + Zn ions + Cu ions)) is preferably 1.6 or more, more preferably 1.63 or more, still more preferably 1.65 or more, and further preferably 1.68 or more, 1.7 or more, 1.75 or more, 1.8 or more, 1.85 or more, 2.00 or more, 2.20 or more, 2.40 or more, 2.60 or more, 2.80 or more in this order.

[0042] The above glass can further optionally contain one or more of the following cations as cations.

[0043] Ions of rare earth atoms such as Y ions, La ions, Gd ions, and Yb ions, when introduced into the glass in a small amount, can contribute to further improvement of weather resistance, improvement of chemical resistance, suppression of a decrease in glass transition temperature, and / or suppression of a decrease in viscosity at the liquidus temperature. The content of these ions of rare earth atoms can each be 0%, 0% or more, or more than 0%, and can also be 3.0% or less, 2.0% or less, 1.0% or less, or 0.5% or less. The formal valences of Y ions, La ions, Gd ions, and Yb ions are +3.

[0044] Ti, Zr, Nb, W, and Bi are components that contribute to improvement of the weather resistance of the glass, improvement of chemical resistance, and suppression of a decrease in Tg and a decrease in liquidus viscosity when added in a small amount. The Ti ion content can be 0%, 0% or more, or more than 0%, and is preferably 3.0% or less, more preferably 2.0% or less, still more preferably 1.0% or less, and even more preferably 0.5% or less. The formal valence of Ti ions is +4. The Zr ion content can be 0%, 0% or more, or more than 0%, and is preferably 3.0% or less, more preferably 2.0% or less, still more preferably 1.0% or less, and even more preferably 0.5% or less. The formal valence of Zr ions is +4. The Nb ion content can be 0%, 0% or more, or more than 0%, and is preferably 3.0% or less, more preferably 2.0% or less, still more preferably 1.0% or less, and even more preferably 0.5% or less. The formal valence of Nb ions is +5. The W ion content can be 0%, 0% or more, or more than 0%, preferably 3.0% or less, more preferably 2.0% or less, still more preferably 1.0% or less, and even more preferably 0.5% or less. The formal valence of the W ion is +6. The Bi ion content can be 0%, 0% or more, or more than 0%, preferably 3.0% or less, more preferably 2.0% or less, still more preferably 1.0% or less, and even more preferably 0.5% or less. The formal valence of the Bi ion is +3.

[0045] From the viewpoint of improving the visible light transmittance, the average valence of cations excluding Cu ions and P ions in the above glass is less than 1.500, preferably 1.490 or less, more preferably 1.480 or less, still more preferably 1.470 or less, even more preferably 1.460 or less, still even more preferably 1.450 or less, still even more preferably 1.440 or less, still even more preferably 1.430 or less, and still even more preferably 1.420 or less, 1.410 or less, 1.400 or less, 1.390 or less, 1.380 or less, 1.370 or less, 1.360 or less, 1.350 or less in this order. Also, from the viewpoint of suppressing the decrease in viscosity at the liquidus temperature, the average valence of cations excluding Cu ions and P ions is preferably 1.100 or more, more preferably 1.1500 or more, more preferably 1.200 or more, still more preferably 1.250 or more, even more preferably 1.270 or more, still even more preferably 1.280 or more, still even more preferably 1.290 or more, and still even more preferably 1.300 or more. For example, when changing the Cu concentration in adjusting the glass thickness or the wavelength at which the transmittance becomes 50%, the composition can be readjusted with reference to the above average valence.

[0046] The above average valence number is obtained by dividing the sum of "content of each cation at cation % × formal valence number of that cation" for cations excluding Cu ions and P ions by the total content of cations excluding Cu and P at cation %. For example, for a glass containing, in addition to Cu ions and P ions, A cation (formal valence number a, content A% at cation %), B cation (formal valence number b, content B% at cation %), and C cation (formal valence number c, total content C% at cation %), the above average valence number is obtained as "(A × a + B × b + C × c) / (A + B + C)".

[0047] When adjusting the Cu concentration in the above glass when adjusting the glass thickness and the wavelength at which the transmittance becomes 50%, the average valence number containing Cu ions can also be referred to. For cations excluding only P ions (therefore including Cu ions), the average valence number of cations obtained in the same manner as above is preferably 1.550 or less, more preferably 1.540 or less, still more preferably 1.530 or less, even more preferably 1.520 or less, yet more preferably 1.510 or less, still more preferably 1.500 or less, and further preferably 1.490 or less, 1.480 or less, 1.470 or less, 1.460 or less, 1.450 or less, 1.440 or less, 1.430 or less, 1.420 or less, 1.410 or less, 1.400 or less in this order from the viewpoint of further improving the visible light transmittance. Also, from the viewpoint of suppressing the decrease in viscosity at the liquidus temperature, the average valence number of cations excluding only P ions is preferably 1.300 or more, more preferably 1.310 or more, still more preferably 1.320 or more, even more preferably 1.330 or more, yet more preferably 1.340 or more, still more preferably 1.350 or more, and even more preferably 1.360 or more.

[0048] (Anions) The above glass contains O ions as constituent ions. From the viewpoint of facilitating homogenization during melting of the glass and enhancing productivity, the O ion content is 85.0% or more, preferably 90.0% or more, more preferably 95.0% or more, still more preferably 98.0% or more, and even more preferably 99.0% or more. Particularly from the viewpoint of suppressing volatilization during glass melting, enhancing productivity, and suppressing generation of harmful gases during manufacturing, it is preferable that the content of O ions is 100%. Incidentally, the formal valence of O ions is -2.

[0049] The above glass can contain only O ions in one form as anions, and can contain one or more other anions together with O ions in another form. Examples of the other anions include F ions, Cl ions, Br ions, I ions, etc. Incidentally, the formal valences of F ions, Cl ions, Br ions, and I ions are -1.

[0050] From the viewpoints of improving the homogeneity and strength of the glass, the content of F ions is preferably 15.0% or less, more preferably 10.0% or less, still more preferably 5.0% or less, even more preferably 2.0% or less, and even more preferably 1.0% or less. Particularly from the viewpoint of suppressing volatilization during glass melting, enhancing productivity, and suppressing generation of harmful gases during manufacturing, it is also possible not to contain F ions.

[0051] From the viewpoint of improving weather resistance, the ratio of the content of O ions to the content of P ions (O ions / P ions) in the above glass is 3.300 or more, preferably 3.310 or more, more preferably 3.320 or more, still more preferably 3.330 or more, and further preferably 3.340 or more, 3.350 or more, 3.360 or more, 3.370 or more, 3.380 or more, 3.390 or more, 3.400 or more, 3.410 or more, 3.420 or more, 3.430 or more, 3.440 or more, 3.450 or more, 3.460 or more in this order. Further, from the viewpoint of further improving the devitrification resistance and near-infrared cut-off ability during melting and forming of the glass, the above ratio (O ions / P ions) is preferably 3.580 or less, more preferably 3.570 or less, still more preferably 3.560 or less, still more preferably 3.550 or less, even more preferably 3.540 or less, still even more preferably 3.530 or less, and further preferably 3.520 or less, 3.510 or less, 3.500 or less, 3.490 or less in this order.

[0052] The above glass is preferably basically composed of the above components, but it is also possible to contain other components as long as the effects exerted by the above components are not hindered. Further, the above glass does not exclude the inclusion of inevitable impurities.

[0053] Pb, As, Cd, Tl, Be, and Se all have toxicity. Therefore, it is preferable that the above glass does not contain these as glass components.

[0054] U, Th, and Ra are all radioactive elements. Therefore, it is preferable that the above glass does not contain these as glass components.

[0055] V, Cr, Mn, Fe, Co, Ni, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Ce can increase the coloring of the glass and can be a source of fluorescence. Therefore, in the above glass, the total content of these elements in terms of oxide conversion based on oxide glass is preferably 10 ppm by mass or less, and more preferably these elements are not contained as glass components.

[0056] Ge, Ta, and Gd are expensive raw materials. Therefore, it is preferable that the above glass does not contain these as glass components.

[0057] Sb (Sb2O3), Sn (SnO2), Ce (CeO2), and SO3 are optionally addable elements that function as fining agents. Among these, Sb (Sb2O3) is a fining agent with a large fining effect. Sn (SnO2) and Ce (CeO2) have a smaller fining effect compared to Sb (Sb2O3). When these fining agents are added in large amounts, the coloring of the glass tends to intensify. Therefore, when adding a fining agent, it is preferable to add Sb (Sb2O3) while considering the influence of coloring due to the addition.

[0058] Regarding the content of the components that can function as fining agents described below, the values in terms of oxide conversion are shown.

[0059] The content of Sb2O3 is expressed as an external division. That is, when the total content of all glass components other than Sb2O3, SnO2, CeO2, and SO3 as oxides is 100.0% by mass, the content of Sb2O3 in one form can be less than 1.0% by mass, less than 0.5% by mass, 0.3% by mass or less, 0.2% by mass or less, 0.15% by mass or less, 0.1% by mass or less, or less than 0.1% by mass. In one form, the content of Sb2O3 can be 0% by mass. Also, in another form, the content of Sb2O3 can be more than 0% by mass. During melting, Cu 2+From the viewpoint of increasing the visible light transmittance by suppressing the coloring caused by reduction, the content of Sb2O3 is preferably more than 0 mass%, more preferably 0.01 mass% or more, still more preferably 0.03 mass% or more, yet more preferably 0.05 mass% or more, and even more preferably 0.08 mass% or more, and still even more preferably 0.10 mass% or more.

[0060] The content of SnO2 is also expressed as an external division. That is, when the total content of oxides of all glass components other than SnO2, Sb2O3, CeO2 and SO3 is 100.0 mass%, the content of SnO2 is preferably less than 2.0 mass%, more preferably less than 1.0 mass%, still more preferably less than 0.5 mass%, and even more preferably less than 0.1 mass%. The content of SnO2 may be 0 mass%. By setting the content of SnO2 within the above range, the clarity of the glass can be improved.

[0061] The content of CeO2 is also expressed as an external division. That is, when the total content of oxides of all glass components other than CeO2, Sb2O3, SnO2 and SO3 is 100.0 mass%, the content of CeO2 is preferably less than 2.0 mass%, more preferably less than 1.0 mass%, still more preferably less than 0.5 mass%, and even more preferably less than 0.1 mass%. The content of CeO2 may be 0 mass%. By setting the content of CeO2 within the above range, the clarity of the glass can be improved.

[0062] The content of SO3 is also expressed as an external division. That is, SO 3、 When the total content of oxides of all glass components other than Sb2O3, SnO2, and CeO2 is 100.0 mass%, the content of SO3 is preferably less than 2.0 mass%, more preferably less than 1.0 mass%, still more preferably less than 0.5 mass%, and even more preferably less than 0.1 mass%. The content of SO3 may be 0 mass%. By setting the content of SO3 within the above range, the clarity of the glass can be improved.

[0063] <Glass physical properties> (Transmittance characteristics) The above glass is suitable as a glass for a near-infrared cut filter. Regarding the near-infrared cut ability, the half-value, which is the wavelength at which the spectral transmittance becomes 50% at a wavelength of 600 nm or more, can be used as an index, and the transmittance T1200 at a wavelength of 1200 nm can also be used as an index. Also, the above glass can exhibit a high visible light transmittance. Regarding the visible light transmittance, the transmittance T400 at a wavelength of 400 nm can be used as an index. As will be described in detail later, in one form, the above glass can be used as a glass for a near-infrared cut filter with a thickness of 0.25 mm or less. Among the above thickness ranges, as a glass (Glass I) suitable for a near-infrared cut filter with a relatively thin thickness, as the transmittance characteristics in terms of a thickness of 0.11 mm, the half-value is preferably 650 nm or less, and more preferably 647 nm or less, 645 nm or less, 643 nm or less, 641 nm or less, 640 nm or less, 639 nm or less, 638 nm or less in that order. Regarding Glass I, as the transmittance characteristics in terms of a thickness of 0.11 mm, the half-value is preferably 600 nm or more, and more preferably 610 nm or more, 613 nm or more, 615 nm or more, 617 nm or more, 620 nm or more, 623 nm or more, 625 nm or more, 628 nm or more in that order. Regarding Glass I, as the transmittance characteristics in terms of a thickness of 0.11 mm, the transmittance T1200 at a wavelength of 1200 nm is preferably 42.0% or less, and more preferably 41.0% or less, 40.0% 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 in that order. Regarding Glass I, as the transmittance characteristics in terms of a thickness of 0.11 mm, the transmittance T1200 at a wavelength of 1200 nm can be, for example, 10.0% or more, 12.0% or more, or 14.0% or more. However, since it can be said that a lower transmittance means better near-infrared cut ability, it is also preferable to be lower than the above-exemplified values. Further, as Glass I, in terms of the transmittance characteristics in terms of a thickness of 0.11 mm, the transmittance T400 at a wavelength of 400 nm is preferably 68.0% or more, more preferably 70.0% or more, and further preferably 71.0% or more, 72.0% or more, 73.0% or more, 74.0% or more, 75.0% or more, 76.0% or more, 77.0% or more, 78.0% or more, 79.0% or more, 80.0% or more in that order. Regarding Glass I, in terms of the transmittance characteristics in terms of a thickness of 0.11 mm, the transmittance T400 at a wavelength of 400 nm can be, for example, 98.0% or less, 97.0% or less, or 96.0% or less. However, since it can be said that a higher transmittance means better visible light transmittance, it is also preferable to exceed the above-exemplified values. Further, among the above thickness ranges, as the glass (Glass II) suitable for a near-infrared cut filter having a relatively large thickness, in terms of the transmittance characteristics in terms of a thickness of 0.21 mm, the half-value is preferably 650 nm or less, and further preferably 647 nm or less, 645 nm or less, 643 nm or less, 641 nm or less, 640 nm or less, 639 nm or less, 638 nm or less in that order. Regarding Glass II, in terms of the transmittance characteristics in terms of a thickness of 0.11 mm, the half-value is preferably 600 nm or more, and more preferably 610 nm or more, 613 nm or more, 615 nm or more, 617 nm or more, 620 nm or more, 623 nm or more, 625 nm or more, 628 nm or more in that order. Regarding Glass II, in terms of the transmittance characteristics in terms of a thickness of 0.21 mm, the transmittance T1200 at a wavelength of 1200 nm is preferably 42.0% or less, and further preferably 41.0% or less, 40.0% 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 in that order. Regarding Glass II, as the transmittance characteristics in terms of a thickness equivalent of 0.21 mm, the transmittance T1200 at a wavelength of 1200 nm can be, for example, 10.0% or more, 12.0% or more, or 14.0% or more. However, since a lower such transmittance can mean better near-infrared cut-off ability, it is also preferable that it is less than the values exemplified above. Also, for Glass II, as the transmittance characteristics in terms of a thickness equivalent of 0.21 mm, the transmittance T400 at a wavelength of 400 nm is preferably 68.0% or more, more preferably 70.0% or more, and even more preferably 71.0% or more, 72.0% or more, 73.0% or more, 74.0% or more, 75.0% or more, 76.0% or more, 77.0% or more, 78.0% or more, 79.0% or more, 80.0% or more, in that order. Regarding Glass II, as the transmittance characteristics in terms of a thickness equivalent of 0.21 mm, the transmittance T400 at a wavelength of 400 nm can be, for example, 98.0% or less, 97.0% or less, or 96.0% or less. However, since a higher such transmittance can mean better visible light transmittance, it is also preferable that it is more than the values exemplified above.

[0064] The above transmittance characteristics are values obtained by the following method. Process a glass sample so that it has planes that are parallel to each other and optically polished, and measure the external transmittance at wavelengths from 200 to 1200 nm. Note that the external transmittance also includes the reflection loss of light at the sample surface. Taking the intensity of the light incident perpendicularly to one of the optically polished planes as intensity A and the intensity of the light exiting from the other plane as intensity B, calculate the spectral transmittance B / A. The wavelength at which the spectral transmittance becomes 50% at wavelengths of 600 nm or more is the half-value λ T 50. Let the spectral transmittance at a wavelength of 400 nm be T400, and the spectral transmittance at a wavelength of 1200 nm be T1200. Also, when the glass to be measured is not a glass with the equivalent thickness being converted, taking the thickness of that glass as d, assume that the transmittance at each wavelength λ is converted by the following formula, and from the transmittance characteristics obtained by the conversion, the half-value λ TThe conversion values of 50, T400, and T1200 can be obtained.

[0065] T(λ)=(1 - R(λ)) 2 × exp(log e ((T0(λ) / 100) / (1 - R(λ)) 2 ) × d / d0) × 100

[0066] In the formula, T(λ): conversion transmittance (%) at wavelength λ, T0(λ): measured transmittance (%) at wavelength λ, d: thickness of the glass (mm), d0: thickness to be converted (mm), R(λ) = ((n(λ) - 1) / (n(λ) + 1)) 2 which is the reflectance at wavelength λ, and n(λ): refractive index at wavelength λ. Here, calculate by regarding n(λ) = 1.51680 and R(λ) = 0.042165 as constants.

[0067] (Weather resistance) Due to having the composition described above, the glass can exhibit excellent weather resistance. Regarding the weather resistance, for example, the evaluation results of the weather resistance evaluated by the method described in the examples below can be used as an index, and it is preferable that such evaluation results are ◎ or 〇, and more preferably ◎.

[0068] (Melting property) Due to having the composition described above, the glass can also exhibit excellent melting property. Regarding the melting property, for example, the evaluation results of the melting property evaluated by the method described in the examples below can be used as an index, and it is preferable that such evaluation results are 〇.

[0069] (Glass transition temperature Tg, temperature Tm at which the endothermic reaction converges) The glass transition temperature of the above glass is not particularly limited, but from the viewpoints of imparting processability and / or heat resistance in subsequent processes, etc., Tg is preferably 300 °C or higher, and more preferably 310 °C or higher, 320 °C or higher, 330 °C or higher, 340 °C or higher, 350 °C or higher in this order. On the other hand, from the perspective of reducing the burden on the annealing furnace and the forming apparatus, it is preferable that Tg is 500°C or lower, and more preferably 490°C or lower, 480°C or lower, 470°C or lower, 460°C or lower, 450°C or lower, 440°C or lower, 430°C or lower, 420°C or lower, 410°C or lower, 400°C or lower, 390°C or lower, in that order. The temperature Tm at which the endothermic reaction of the above glass converges is not particularly limited, but the lower Tm is, the better the meltability tends to be. Also, the higher the meltability, the more likely it is to increase the visible light transmittance of the glass. From these perspectives, it is preferable that Tm is 870°C or lower, and more preferably 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, in that order.

[0070] (Specific gravity) It is preferable that the near-infrared cut filter is lightweight because it leads to weight reduction of the elements and devices in which this filter is incorporated. From this point, the specific gravity of the above glass is preferably 3.50 or lower, and more preferably 3.45 or lower, 3.40 or lower, 3.35 or lower, 3.30 or lower, 3.25 or lower, 3.20 or lower, 3.15 or lower, 3.10 or lower, 3.05 or lower, in that order. The specific gravity can be, for example, 2.5 or more or 2.6 or more, but since it is preferable that the specific gravity is low from the above perspectives, it is also preferable to be below the values exemplified here.

[0071] <Manufacturing method of glass> The above glass can be obtained by preparing, melting, and forming various glass raw materials. Regarding the manufacturing method, reference can also be made to the description below.

[0072] The above near-infrared absorbing glass is suitable as glass for a near-infrared cut filter. Also, the above near-infrared absorbing glass can be applied to optical elements (such as lenses) other than the near-infrared cut filter, and furthermore, it can be applied to various glass products and various modifications are also possible.

[0073] [Near-infrared cut filter] One aspect of the present invention relates to a near-infrared cut filter made of the above-mentioned near-infrared absorbing glass (hereinafter, also simply referred to as "filter").

[0074] The glass constituting the above filter is as described above.

[0075] Specific examples of the manufacturing method of the above filter will be described below. However, the following manufacturing methods are illustrative and do not limit the present invention.

[0076] The molten glass is weighed and mixed with glass raw materials such as phosphates, oxides, carbonates, nitrates, sulfates, fluorides, etc. as appropriate so as to have a desired composition, and then melted in a melting container such as a platinum crucible at, for example, 800°C to 1000°C. At that time, a lid made of platinum or the like can also be used to suppress the volatilization of volatile components. Further, the melting can be carried out in the air, and in order to suppress the valence change of Cu, it can be in an oxygen atmosphere or oxygen can be bubbled into the molten glass. The molten glass becomes a homogenized molten glass with reduced bubbles (preferably bubble-free) by stirring and clarification.

[0077] After stirring and clarifying the molten glass, the glass is poured out and formed into a desired shape. When pouring out the glass, it is preferable to cool it to a temperature near the liquid phase temperature to increase the viscosity of the glass, because convection of the poured-out glass is less likely to occur and streaks are less likely to occur.

[0078] As a method for forming the glass, known methods such as casting, pipe outflow, roll, press, etc. can be used. The formed glass is transferred to an annealing furnace preheated to near the glass transition point and gradually cooled to room temperature. Thus, a near-infrared cut filter can be manufactured.

[0079] An example of the molding method will be described below. A mold is prepared that is composed of a flat and horizontal bottom surface, a pair of side walls that face each other in parallel across the bottom surface, and a dam plate that blocks one of the openings located between the pair of side walls. Homogenized molten glass is poured into the mold from a platinum alloy pipe at a constant flow rate. The poured molten glass spreads in the mold and is formed into a glass plate restricted to a constant width by the pair of side walls. The formed glass plate is continuously drawn 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, a large and thick glass block can be formed. The molded glass molded body is transferred to an annealing furnace that has been heated to near the glass transition temperature in advance, and is slowly cooled to room temperature. The glass molded body that has been slowly cooled to remove distortion is subjected to mechanical processing such as slicing, grinding, and polishing. In this way, a near-infrared cut filter having a shape according to the application, such as a plate shape or a lens shape, can be obtained. Alternatively, a method can be used in which a preform made of the above glass is molded, and the preform is heated, softened, and press molded (particularly a precision press molding method in which the final product is press molded without performing mechanical processing such as grinding and polishing on the optically functional surface). An optical multilayer film can be formed on the surface of the filter as necessary.

[0080] The near-infrared cut filter has both excellent near-infrared cut ability and high visible light transmittance, and is capable of satisfactorily correcting the color sensitivity of a semiconductor imaging device.

[0081] Moreover, the near-infrared cut filter can be applied to an imaging device by combining it with a semiconductor image sensor. The semiconductor image sensor is a package in which a semiconductor imaging element such as a CCD or a CMOS is mounted, and the light receiving section is covered with a light-transmitting member. The light-transmitting member can also be the near-infrared cut filter, or the light-transmitting member can be separate from the near-infrared cut filter.

[0082] The above imaging device can also be provided with an optical element such as a lens or a prism for forming an image of a subject on the light-receiving surface of the semiconductor image sensor.

[0083] Further, according to the above near-infrared cut filter, color sensitivity correction can be favorably performed, and an imaging device capable of obtaining an image with excellent image quality can be provided.

[0084] In one form, the above near-infrared cut filter can be a near-infrared cut filter having a thickness of 0.25 mm or less. In recent years, with the emergence of smartphones, the tendency for the camera thickness of imaging elements to decrease has been remarkable, and accordingly, it has been desired that the near-infrared cut filter also exhibit performance with a thinner thickness. The above near-infrared cut filter is also suitable as such a near-infrared cut filter. The thickness of the above 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 near-infrared cut filter can be, for example, 0.21 mm or 0.11 mm. Further, the thickness of the above near-infrared cut filter can be, for example, 0.50 or more, but is not limited thereto. In the present invention and this specification, "thickness" refers to the thickness of the sample in the region where the transmittance is measured, and can be measured by a thickness gauge, a micrometer, or the like. For example, the thickness at substantially the center of the position where the transmitted light passes may be measured, or the thicknesses at a plurality of points within the spot of the transmitted light may be measured and the average value thereof may be taken.

[0085] Regarding the near-infrared cut ability of the above near-infrared cut filter, from the viewpoint of making the near-infrared cut filter exhibit even more excellent near-infrared cut ability, the value calculated as "thickness × Cu concentration" is preferably 0.2000 mol / m 2 or more, and further preferably 0.2100 mol / m 2 or more, 0.2200 mol / m 20.2300 mol / m or more 2 0.2400 mol / m or more 2 0.2500 mol / m or more 2 0.2600 mol / m or more 2 0.2700 mol / m or more 2 0.2800 mol / m or more 2 0.2900 mol / m or more 2 0.3000 mol / m or more 2 0.3100 mol / m or more 2 0.3150 mol / m or more 2 0.3200 mol / m or more 2 0.3250 mol / m or more 2 They are preferably in the above order. Also, from the viewpoint of obtaining a near-infrared cut filter having a higher visible light transmittance, the value calculated as "thickness × Cu concentration" is preferably 1.000 mol / m or less, and more preferably 0.9800 mol / m or less, 0.9600 mol / m or less, 0.9400 mol / m or less, 0.9200 mol / m or less, 0.9000 mol / m or less, 0.8800 mol / m or less, 0.8600 mol / m or less, 0.8400 mol / m or less, 0.8200 mol / m or less, 0.8000 mol / m or less, 0.7800 mol / m or less, 0.7600 mol / m or less, 0.7400 mol / m or less, 0.7200 mol / m or less, 0.7000 mol / m or less, 0.6800 mol / m or less, 0.6600 mol / m or less, 0.6400 mol / m or less, 0.6200 mol / m or less, 0.6000 mol / m or less, 0.5800 mol / m or less. 2 0.9800 mol / m or less 2 0.9600 mol / m or less 2 0.9400 mol / m or less 2 0.9200 mol / m or less 2 0.9000 mol / m or less 2 0.8800 mol / m or less 2 0.8600 mol / m or less 2 0.8400 mol / m or less 2 0.8200 mol / m or less 2 0.8000 mol / m or less 2 0.7800 mol / m or less 2 0.7600 mol / m or less 2 0.7400 mol / m or less 2 0.7200 mol / m or less 2 0.7000 mol / m or less 2 0.6800 mol / m or less 2 0.6600 mol / m or less 2 0.6400 mol / m or less 2 0.6200 mol / m or less 2 0.6000 mol / m or less 2 0.5800 mol / m or less2 The following is 0.5600 mol / m 2 The following is 0.5400 mol / m 2 The following is 0.5200 mol / m 2 The following is 0.5000 mol / m 2 The following is 0.4800 mol / m 2 The following is 0.4600 mol / m 2 The following is 0.4800 mol / m 2 The following is 0.4200 mol / m 2 The following is 0.4100 mol / m 2 The following is 0.4000 mol / m 2 The following is 0.3900 mol / m 2 The following is 0.3800 mol / m 2 The following is 0.3700 mol / m 2 The following is 0.3600 mol / m 2 The following is 0.3500 mol / m 2 It is preferably in the following order.

[0086] The calculation method of the above "thickness × Cu concentration" will be described. "Thickness × Cu concentration" = (Specific gravity of the composition) / (molecular weight of the composition) × (cation % of Cu ions / 100) × d / 10 × 10 4 The unit is mol / m 2 where d is the thickness (mm).

[0087] Regarding the (molecular weight of the composition) in the above formula, the calculation method will be described. (Molecular weight of the composition) is, for all components constituting the composition, (Molecular weight of each component based on cation) × (cation % of each component / 100) The sum of these values, and the unit is g / mol. Furthermore, regarding the above (molecular weight of each component based on cation), the calculation method will be described. (Molecular weight of each component based on cation) = (Atomic weight of the element forming the cation) + (coefficient according to the valence of oxygen)

[0088] The coefficient according to the valence is as follows. If the formal valence + 1, the coefficient is 0.5 If the formal valence + 2, the coefficient is 1.0 If the formal valence + 3, the coefficient is 1.5 If the formal valence + 4, the coefficient is 2.0 If the formal valence + 5, the coefficient is 2.5 If the formal valence + 6, the coefficient is 3.0

[0089] Regarding the transmittance characteristics of the above near-infrared cut filter, reference can be made to the previous description regarding Glass I and Glass II. Also, regarding the physical properties of the above near-infrared cut filter, reference can be made to the previous description regarding the above near-infrared absorbing glass.

Examples

[0090] Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to the form of the examples.

[0091] [Examples 1 to 81, Comparative Examples A to F] As glass raw materials, phosphates, fluorides, carbonates, nitrates, oxides, etc. were weighed and mixed so as to obtain 150 g to 300 g of glass having the composition shown in Table 1, and were put into a platinum crucible or a quartz crucible, melted at 800°C to 1000°C for 60 minutes to 180 minutes, stirred to defoam and homogenize, and then poured into a preheated mold and formed into a predetermined shape. The obtained glass formed body was transferred to an annealing furnace heated near the glass transition temperature and slowly cooled to room temperature. A test piece was cut out from the obtained glass, and both sides were mirror-polished to a thickness of about 0.2 mm, and then various evaluations were performed by the following methods.

[0092] [Evaluation Method] <Transmittance Characteristics> The transmittance of each test piece at wavelengths of 200 to 1200 nm was measured using a spectrophotometer. From the measurement results, as values converted to a thickness of 0.11 mm or a thickness of 0.21 mm, the half-value (unit: nm), the transmittance T1200 at a wavelength of 1200 nm (unit: %) and the transmittance T400 at a wavelength of 400 nm (unit: %) were determined.

[0093] <Glass transition temperature Tg, temperature Tm at which the endothermic reaction converges> Using a differential scanning calorimeter (DSC8270) manufactured by Rigaku Corporation, the glass transition temperature Tg and the temperature Tm at which the endothermic reaction due to melting converges were measured at a heating rate of 10 °C / min.

[0094] <Specific gravity> The specific gravity was measured by the Archimedes method.

[0095] <Weather resistance> Each test piece was held in a thermo-hygrostat at a temperature of 85 °C and a relative humidity of 85% for 168 hours. Thereafter, each test piece was subjected to visual appearance evaluation under a fluorescent lamp. From the evaluation results, the weather resistance was evaluated according to the following criteria. ◎: No change in the surface was observed. 〇: Cloudiness was observed on the surface, but no deliquescence. ×: Deliquescence occurred.

[0096] <Meltability> Using the same formulation as the glass raw material used for the preparation of the test piece, after weighing and mixing the raw materials (mixture) sufficient to obtain 200 g of glass after melting, it was put into a platinum crucible or a silica glass crucible and melted at 1000 °C for 60 minutes. As a result of visual observation, when a melt was obtained without residue, it was evaluated as "〇", and when there was residue, it was evaluated as "×".

[0097] The above results are shown in Table 1 (Table 1-1 to Table 1-6), Table 2 (Table 2-1 to Table 2-6), and Table 3 (Table 3-1 to Table 3-6). In the table, the unit of the (total) content of cations is cation %, and the unit of the (total) content of anions is anion %.

[0098]

Table 1-1

[0099]

Table 1-2

[0100]

Table 1-3

[0101]

Table 1-4

[0102]

Table 1-5

[0103]

Table 1-6

[0104]

Table 2-1

[0105]

Table 2-2

[0106]

Table 2-3

[0107]

Table 2-4

[0108]

Table 2-5

[0109]

Table 2-6

[0110]

Table 3-1

[0111]

Table 3-2

[0112]

Table 3-3

[0113]

Table 3-4

[0114]

Table 3-5

[0115]

Table 3-6

[0116] As glass raw materials, phosphates, fluorides, carbonates, nitrates, oxides, etc. were weighed and mixed so that 150 g to 300 g of glass having a composition in which Sb2O3 was contained at 0.080 mass% in an external division display in the composition of Example 64 in Table 1 was obtained. The mixture was put into a platinum crucible or a quartz crucible, melted under the same melting conditions as in Example 64, stirred for defoaming and homogenization, then poured into a preheated mold and formed into a predetermined shape. The obtained glass formed body was transferred to an annealing furnace heated near the glass transition temperature and slowly cooled to room temperature. A test piece was cut out from the obtained glass, and after mirror-polishing both sides to a thickness of about 0.2 mm, the transmittance characteristics were evaluated by the above method. The evaluation results were that the transmittance T1200 at a wavelength of 1200 nm was 27.9% and the transmittance T400 at a wavelength of 400 nm was 87.4% as values at a thickness of 0.11 mm (converted). From the comparison between the above evaluation results and the evaluation results of Example 64, it was confirmed that the addition of Sb2O3 can suppress coloring and increase the visible light transmittance.

[0117] Finally, the above aspects are summarized.

[0118] According to one aspect, as constituent ions, it contains at least one ion selected from the group consisting of P ions, Cu ions, O ions, Li ions, Na ions, and K ions, and at least one ion selected from the group consisting of Mg ions, Ca ions, Sr ions, and Ba ions. In the glass composition expressed in cation %, the content of Cu ions is 15.0 cation % or less, the content of P ions is 55.0 cation % or less, and the cation ratio of the total content of Al ions and P ions to the total content of Mg ions, Ca ions, Sr ions, Ba ions, Zn ions, and Cu ions ((Al ions + P ions) / (Mg ions + Ca ions + Sr ions + Ba ions + Zn ions + Cu ions)) is 5.300 or less. The cation ratio of the total content of Mg ions, Ca ions, Sr ions, and Ba ions to the total content of Li ions, Na ions, and K ions ((Mg ions + Ca ions + Sr ions + Ba ions) / (Li ions + Na ions + K ions)) is 0.100 or more. The average valence number of cations excluding Cu ions and P ions is less than 1.500. In the glass composition expressed in anion %, the content of O ions is 85.0 anion % or more, and the ratio of the content of O ions to the content of P ions (O ions / P ions) is 3.300 or more, thereby providing a near-infrared absorbing glass.

[0119] The above glass can be a near-infrared absorbing glass that is excellent in near-infrared cut ability, has a high visible light transmittance, and is excellent in weather resistance and meltability.

[0120] In one form, in the glass composition of the above glass expressed in cation %, the content of P ions can be 30.0 cation % or more and 50.0 cation % or less.

[0121] In one form, in the glass composition of the above glass expressed in cation %, the content of Li ions can be 10.0 cation % or more.

[0122] In one form, in the glass composition expressed in cation % of the above glass, the content of Cu ions can be 2.1 cation % or more and 15.0 cation % or less.

[0123] In one form, the above ratio (O ion / P ion) can be 3.400 or more.

[0124] In one form, in the glass composition expressed in cation % of the above glass, the cation ratio of Zn ions to the total content of Mg ions, Ca ions, Sr ions, Ba ions and Zn ions (Zn ions / (Mg ions + Ca ions + Sr ions + Ba ions + Zn ions)) can be 0.600 or less.

[0125] In one form, in the glass composition expressed in anion % of the above glass, the content of O ions can be 90.0 anion % or less.

[0126] In one form, the above glass can have a transmittance T1200 at a wavelength of 1200 nm of 42.0% or less as a transmittance characteristic in terms of a thickness of 0.11 mm.

[0127] In one form, the above glass can have a transmittance T400 at a wavelength of 400 nm of 68.0% or more as a transmittance characteristic in terms of a thickness of 0.11 mm.

[0128] In one form, the above glass can have a transmittance T1200 at a wavelength of 1200 nm of 42.0% or less as a transmittance characteristic in terms of a thickness of 0.21 mm.

[0129] In one form, the above glass can have a transmittance T400 at a wavelength of 400 nm of 68.0% or more as a transmittance characteristic in terms of a thickness of 0.21 mm.

[0130] According to one aspect, there is provided a near-infrared cut filter made of the above near-infrared absorbing glass.

[0131] In one form, the thickness of the above near-infrared cut filter can be 0.25 mm or less.

[0132] In one form, as the transmittance characteristic in terms of a thickness of 0.11 mm, the wavelength at which the transmittance becomes 50% at a wavelength of 600 nm or more can be in the range of 600 nm to 650 nm for the above near-infrared cut filter.

[0133] In one form, as the transmittance characteristic in terms of a thickness of 0.11 mm, the transmittance T1200 at a wavelength of 1200 nm can be 42.0% or less for the above near-infrared cut filter.

[0134] In one form, as the transmittance characteristic in terms of a thickness of 0.11 mm, the transmittance T400 at a wavelength of 400 nm can be 68.0% or more for the above near-infrared cut filter.

[0135] In one form, as the transmittance characteristic in terms of a thickness of 0.21 mm, the wavelength at which the transmittance becomes 50% at a wavelength of 600 nm or more can be in the range of 600 nm to 650 nm for the above near-infrared cut filter.

[0136] In one form, as the transmittance characteristic in terms of a thickness of 0.21 mm, the transmittance T1200 at a wavelength of 1200 nm can be 42.0% or less for the above near-infrared cut filter.

[0137] In one form, as the transmittance characteristic in terms of a thickness of 0.21 mm, the transmittance T400 at a wavelength of 400 nm can be 68.0% or more for the above near-infrared cut filter.

[0138] The embodiments disclosed this time should be considered as illustrative in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and it is intended that all modifications within the meaning and scope equivalent to the scope of claims are included. For example, for the above-exemplified glass composition, by performing the composition adjustment described in the specification, a near-infrared absorbing glass according to one aspect of the present invention can be obtained. In addition, it is of course possible to arbitrarily combine two or more of the matters exemplified or described as preferred ranges in the specification.

Claims

1. As constituent ions, P ions, Cu ions, O ions, one or more ions selected from the group consisting of Li ions, Na ions, and K ions, and one or more ions selected from the group consisting of Mg ions, Ca ions, Sr ions, and Ba ions, are included at least, in the glass composition expressed in cation%, the content of Cu ions is 15.0 cation% or less, the content of P ions is 55.0 cation% or less, the cation ratio ((Al ions + P ions) / (Mg ions + Ca ions + Sr ions + Ba ions + Zn ions + Cu ions)) of the total content of Al ions and P ions to the total content of Mg ions, Ca ions, Sr ions, Ba ions, Zn ions, and Cu ions is 5.300 or less, the cation ratio ((Mg ions + Ca ions + Sr ions + Ba ions) / (Li ions + Na ions + K ions)) of the total content of Mg ions, Ca ions, Sr ions, and Ba ions to the total content of Li ions, Na ions, and K ions is 0.100 or more, the average valence number of cations excluding Cu ions and P ions is less than 1.500, in the glass composition expressed in anion%, the content of O ions is 85.0 anion% or more, and the ratio (O ions / P ions) of the content of O ions to the content of P ions is 3.300 or more, a near-infrared absorbing glass.

2. The near-infrared absorbing glass according to Claim 1, wherein in the glass composition expressed in cation%, the content of P ions is 30.0 cation% or more and 50.0 cation% or less.

3. The near-infrared absorbing glass according to Claim 1 or 2, wherein in the glass composition expressed in cation%, the content of Li ions is 10.0 cation% or more.

4. The near-infrared absorbing glass according to any one of Claims 1 to 3, wherein in the glass composition expressed in cation%, the content of Cu ions is 2.1 cation% or more and 15.0 cation% or less.

5. The near-infrared absorbing glass according to any one of Claims 1 to 4, wherein the ratio (O ions / P ions) is 3.400 or more.

6. In the glass composition expressed in cation %, the cation ratio of Zn ions to the total content of Mg ions, Ca ions, Sr ions, Ba ions and Zn ions (Zn ions / (Mg ions + Ca ions + Sr ions + Ba ions + Zn ions)) is 0.600 or less, The near-infrared absorbing glass according to any one of claims 1 to 5.

7. In the glass composition expressed in anion %, the content of F ions is 10.0 anion % or less, The near-infrared absorbing glass according to any one of claims 1 to 6.

8. As the transmittance characteristics in terms of a thickness of 0.11 mm, the wavelength at which the transmittance becomes 50% at a wavelength of 600 nm or more is in the range of 600 nm to 650 nm, the transmittance T1200 at a wavelength of 1200 nm is 42.0% or less, and the transmittance T400 at a wavelength of 400 nm is 68.0% or more, The near-infrared absorbing glass according to any one of claims 1 to 7.

9. As the transmittance characteristics in terms of a thickness of 0.21 mm, the wavelength at which the transmittance becomes 50% at a wavelength of 600 nm or more is in the range of 600 nm to 650 nm, the transmittance T1200 at a wavelength of 1200 nm is 42.0% or less, and the transmittance T400 at a wavelength of 400 nm is 68.0% or more, The near-infrared absorbing glass according to any one of claims 1 to 7.

10. A near-infrared cut filter made of the near-infrared absorbing glass according to any one of claims 1 to 7.

11. The thickness is 0.25 mm or less, The near-infrared cut filter according to claim 10.

12. As the transmittance characteristics in terms of a thickness of 0.11 mm, the wavelength at which the transmittance becomes 50% after a wavelength of 600 nm is in the range of 600 nm - 650 nm, the transmittance T1200 at a wavelength of 1200 nm is 42.0% or less, and the transmittance T400 at a wavelength of 400 nm is 68.0% or more, The near-infrared cut filter according to claim 10 or 11.

13. As the transmittance characteristics in terms of a thickness of 0.21 mm, the wavelength at which the transmittance becomes 50% after a wavelength of 600 nm is in the range of 600 nm - 650 nm, the transmittance T1200 at a wavelength of 1200 nm is 42.0% or less, and the transmittance T400 at a wavelength of 400 nm is 68.0% or more, The near-infrared cut filter according to claim 10 or 11.

Images