WO2025023184A1 - Glass, near-infrared absorption cut-off filter, and solid-state imaging element - Google Patents

Abstract

The present invention relates to a glass containing, in mol% based on oxides, 25% or more of P₂O₅ and 0.5% or more in total of near-infrared absorbing components, wherein the ratio represented by {[H⁺ _A]/[H⁺ _B]} of the H⁺ concentration [H⁺ _A] on the surface of the glass and the H⁺ concentration [H⁺ _B] at a depth of 100 μm from the surface of the glass is 2 or less.

Description

Glass, near-infrared absorbing cut filter and solid-state image pickup device

The present invention relates to glass, near-infrared absorption cut filters, and solid-state imaging devices.

　Luminance correction filters are used in imaging devices that use solid-state imaging elements such as CCDs (Charge Coupled Devices) mounted on mobile devices, personal computers, and cameras such as single-lens reflex cameras. These luminance correction filters can make the colors in photographs closer to the luminosity of humans.

The above-mentioned visibility correction filter, also known as a near-infrared absorbing filter, is required to have the spectral characteristics of absorbing light in the near-infrared range and transmitting light in the visible range. Therefore, the glass used in near-infrared absorbing cut filters often contains Cu ions to absorb light in the near-infrared range.

　Generally, phosphate glass and fluorophosphate glass are examples of such glasses, but phosphate glass tends to have better spectral characteristics. However, phosphate glass easily reacts with water, is prone to deterioration in high temperature and humidity, and has poor weather resistance. As a result, the film formed on the main surface of the glass is easily peeled off, and the element is easily deteriorated. This is because the P-O-P bonds contained in the phosphate glass are hydrolyzed by water molecules, and the released phosphoric acid floats to the surface of the glass.

In contrast, Non-Patent Document 1 discloses that by adding Al ₂ O ₃ to phosphate glass, a stronger three-dimensional mesh structure is formed, improving weather resistance.

N. J. Kreidl and W. A. Weyl, J. Am. Ceram. Soc. , 24:372-378 (1941)

However, when Al ₂ O ₃ is added to glass, the solubility decreases, and devitrification due to aluminum phosphate is likely to occur. If the melting temperature of the glass is increased to prevent the devitrification, the light transmittance in the visible range decreases. This is thought to be due to a change in the valence of the near-infrared absorbing component, such as a part of the divalent Cu ions that existed to absorb light in the near-infrared range becoming monovalent. Therefore, it is not appropriate to add excessive Al ₂ O ₃ to glass.

The present invention aims to provide a new glass, such as phosphate glass or fluorophosphate glass, that contains phosphorus and also contains a near-infrared absorbing component and has improved weather resistance, as well as a near-infrared absorbing cut filter and a solid-state imaging device made of the above glass.

As a result of intensive research, the present inventors have found that the above-mentioned problems can be solved by controlling the ratio of the H ⁺ concentration at the surface of a glass containing phosphorus and a near-infrared absorbing component to the H ⁺ concentration at a depth of 100 μm from the surface of the glass, and have thus completed the present invention.

That is, the present invention relates to the following [1] to [14].
[1] In mole percent based on oxide,
A glass containing 25% or more of _P2O5 and 0.5% or more of near- _infrared absorbing components in total,
A glass in which the ratio of the H ⁺ concentration [H ⁺ _A ] at the surface of the glass to the H ⁺ concentration [H ⁺ _B ] at a depth of 100 μm from the surface of the glass, expressed as {[H ⁺ _A ]/[H ⁺ _B ]}, is 2 or less.
[2] The glass according to [1] above, having a β-OH value of 1 mm ⁻¹ or less.
[3] The glass according to [1] or [2] above, wherein the ratio represented by {[H ⁺ _A ]/[H ⁺ _B ]} is less than 1.
[4] The glass according to any one of the above [1] to [3], which has a transmittance of 70% or more at a wavelength of 550 nm when converted into a glass with a thickness of 0.2 mm.
[5] The glass according to any one of the above [1] to [4], which has a transmittance of 30% or less at a wavelength of 800 nm when converted into a glass with a thickness of 0.2 mm.
[6] The glass according to any one of the above [1] to [5], containing one or more selected from the group consisting of Cu, Fe, and V as the near infrared absorbing component.
[7] The near infrared absorbing component contains Cu,
The glass according to any one of the above [1] to [6], containing 0.5% or more of CuO in mole percent on an oxide basis.
[8] The glass according to any one of the above [1] to [7], further comprising one or more elements selected from the group consisting of Ti, W, and Nb.
[9] The glass according to [8], containing, in terms of mole percent on an oxide basis, TiO ₂ , WO ₃ and Nb ₂ O ₅ in a total amount of 5% or more.
[10] The content in mole percent based on oxide is:
_P2O5 : _25-80 %,
Al ₂ O ₃ : 1 to 20%,
ΣR ₂ O: 0 to 35% (wherein R represents Li, Na, K, Rb, and Cs);
ΣR′O: 0 to 30% (wherein R′ represents Mg, Ca, Sr, Ba, and Zn), and CuO: 0.5 to 30%;
The ΣR ₂ O means the total content of Li ₂ O, Na ₂ O, K ₂ O, Cs ₂ O, and Rb ₂ O;
The glass according to any one of the above [1] to [9], wherein the ΣR′O represents the total content of MgO, CaO, SrO, BaO, and ZnO.
[11] The content in mole percent based on oxide is:
_P2O5 : _30-50 %,
Al ₂ O ₃ : 1 to 10%,
ΣR ₂ O: 10 to 35% (wherein R represents Li, Na, K, Rb, and Cs);
ΣR′O: 0 to 10% (wherein R′ means Mg, Ca, Sr, Ba and Zn),
CuO: 1-15%,
_TiO2 : 0-10%,
WO ₃ : 0 to 10% and Nb ₂ O ₅ : 0 to 10% are satisfied;
The ΣR ₂ O means the total content of Li ₂ O, Na ₂ O, K ₂ O, Cs ₂ O, and Rb ₂ O;
The glass according to any one of the above [1] to [10], wherein the ΣR′O represents the total content of MgO, CaO, SrO, BaO, and ZnO.
[12] The glass according to any one of the above [1] to [11], wherein the F content, expressed in mol%, is 7% or less by external proportion.
[13] A near-infrared absorption cut filter comprising the glass according to any one of [1] to [12] above.
[14] A solid-state imaging device comprising the near-infrared absorption cut filter according to [13].

According to the present invention, a new glass having improved weather resistance can be obtained. Moreover, even for a glass having a conventionally known composition, the weather resistance can be improved by controlling the ratio of the H ⁺ concentration at the surface to the H ⁺ concentration at a depth of 100 μm from the glass surface.
As a result, it is possible to provide a suitable near-infrared absorption cut filter having excellent weather resistance, and a solid-state imaging device including the near-infrared absorption cut filter.

The present invention will be described in detail below, but the present invention is not limited to the following embodiments, and can be modified as desired without departing from the gist of the present invention. In addition, the use of "~" to indicate a numerical range means that the numerical values before and after it are included as the lower and upper limits.

Glass
The glass according to this embodiment contains, in terms of mole percent on an oxide basis, 25% or more of _P2O5 and 0.5% or more of near-infrared absorbing components in total. The ratio of the H ⁺ concentration [H _{+ A} ] at the surface of the glass to the H ⁺ concentration [H ⁺ _B ] at a depth of 100 μm from the surface of the glass, expressed as {[H ^{+ A} ]/[H ⁺ _B ]}, is ₂ or less.

Physical Properties
When excess Al ₂ O ₃ is added to glass containing phosphorus and a near-infrared absorbing component to improve its weather resistance and the melting temperature of the glass is raised to prevent devitrification, the light transmittance in the visible range decreases. This is thought to be due to a change in the valence of the near-infrared absorbing component, such as some of the divalent Cu ions that exist to absorb light in the near-infrared range becoming monovalent.

Therefore, the present inventors have conducted studies to improve the weather resistance of glass containing phosphorus and a near-infrared absorbing component in addition to the addition of Al ₂ O ₃ , and have found that the weather resistance of the glass is improved by setting the ratio represented by {[H ⁺ _A ]/[H ⁺ _B ]} to 2 or less.

The reason for this is unclear, but it is thought to be as follows.
By reducing the H ⁺ concentration [H ⁺ _A ] at the surface of the glass to less than twice the H ⁺ concentration [H ⁺ _B ] at a depth of 100 μm from the surface of the glass, the P-O-P bonds in the glass are increased, and the glass network is strengthened. This makes it possible to suppress the intrusion and diffusion of moisture (H ₂ O) into the glass. This is because the number of terminal phosphate groups (P-OH) is reduced. As a result, the weather resistance of the glass is improved, and it is believed that the glass will be suitable for use, for example, as a near-infrared absorption cut filter.

The present inventors have found a glass having a novel composition as described below, in which the ratio represented by {[H ⁺ _A ]/[H ⁺ _B ]} is equal to or less than 2. In addition, the present inventors have found that even in the case of a glass having a conventionally known composition in which the ratio represented by {[H ⁺ _A ]/[H ⁺ _B ]} exceeds 2, the ratio can be reduced to equal to or less than 2 by carrying out post-treatment, thereby improving weather resistance.

Further studies by the present inventors have revealed that the transmittance of visible light can be improved in addition to weather resistance by making the ratio represented by the above {[H ⁺ _A ]/[H ⁺ _B ]} less than 1. This is believed to be due to the fact that, as the H ⁺ concentration [H ⁺ _A ] on the surface of the glass decreases, components that contribute to the absorption of near-infrared light, such as Cu ²⁺ , which is an ion on the high valence side, tend to be present for charge compensation, and the proportion of components that contribute to the absorption of visible light, such as Cu ^+, which is an ion on the low valence side, decreases. In particular, in the glass according to this embodiment, the decrease in the transmittance in the near-infrared region and the increase in the transmittance in the visible region due to the change in the valence of this Cu ion are important phenomena, and this makes the glass according to this embodiment suitable for use as a near-infrared absorption cut filter.

From the above viewpoints, the ratio represented by {[H ⁺ _A ]/[H ⁺ _B ]} of the glass according to this embodiment is not more than 2, preferably less than 1, more preferably not more than 0.8, and even more preferably not more than 0.5. The lower limit of the ratio represented by {[H ⁺ _A ]/[H ⁺ _B ]} is not particularly limited, but is, for example, not less than 0.01.

In this specification, [H ⁺ _A ] and [H ⁺ _B ] are determined by secondary ion mass spectrometry (SIMS).
Specifically, the H ⁺ concentration (cps) is measured from the surface of the glass to a depth of at least 20 μm using SIMS. The curve obtained from the surface to a depth of 20 μm is then approximated with a sigmoid curve to obtain the H ⁺ concentration [H ⁺ _A ] (cps) at the surface of the glass and the H ⁺ concentration [H ⁺ _B ] (cps) at a depth of 100 μm from the surface of the glass. By using this measurement method, [H ⁺ _B ] can be obtained even if the actual thickness of the glass is less than 100 μm.

The specific measurement conditions for SIMS are as follows.
[SIMS measurement conditions]
Equipment: ULVAC-PHI ADEPT1010
Primary ion species: Cs+
Acceleration voltage of primary ions: 5 kV
Primary ion current value: 500 nA
Incident angle of primary ions: 60° to the normal of the sample surface
Primary ion raster size: 300 x 300 μm ²
Polarity of secondary ions: negative Secondary ion detection area: 60 x 60 μm ² (4% of the raster size of primary ions)
ESA Input Lens: 0
Use of neutralization gun: Yes Method of converting horizontal axis from sputtering time to depth: The depth of the analyzed crater is measured with a stylus surface profiler (Dektak150, manufactured by Veeco) to determine the sputtering rate of the primary ions. Using this sputtering rate, the horizontal axis is converted from sputtering time to depth. Field axis potential during 1H-detection: The optimal value may vary depending on the device. The operator should carefully set the value so that the background is sufficiently cut.

From the viewpoint of further improving the weather resistance of the glass, the β-OH value of the glass according to this embodiment is preferably 1 mm ⁻¹ or less, more preferably 0.8 mm ⁻¹ or less, even more preferably 0.5 mm ⁻¹ or less, and still more preferably 0.25 mm ⁻¹ or less. There is no particular restriction on the lower limit of the β-OH value, but it is, for example, 0.01 mm ⁻¹ or more.
The β-OH value in this specification correlates with the amount of water in the glass, and is determined by dividing the absorbance at 3550 cm ⁻¹ measured by Fourier transform infrared spectroscopy (FT-IR) by the thickness of the glass.
Specifically, when the maximum transmittance between 3650 cm ^-1 and 4000 cm ^-1 is T ₀ , the transmittance at 3550 cm ^-1 is T ₁ , and the glass thickness is d (mm), the β-OH value is expressed by the following formula.
β-OH value = -(1/d)・(log ₁₀ (T ₁ /T ₀ ))

When the glass according to this embodiment is used as a near-infrared absorption cut filter, it is required to have high transmittance of light in the visible range as a spectral characteristic. Therefore, the transmittance of the above glass at a wavelength of 550 nm is preferably 70% or more, more preferably 75% or more, even more preferably 80% or more, and even more preferably 85% or more. In addition, the transmittance is preferably closer to 100%, but is usually 92% or less. In this specification, the transmittance of glass is the external transmittance including reflection loss on the front and back surfaces.

In this specification, the transmittance is calculated based on a glass thickness of 0.2 mm. The above conversion can be performed using the following formula.
T _i2 = T _i1 ^t2/t1
In the above formula, T _i1 is the internal transmittance of the measured sample (transmittance excluding reflection loss on the front and back surfaces), T _i2 is the internal transmittance after conversion, t1 is the thickness (mm) of the measured sample, and t2 is the thickness to be converted, i.e., 0.2 mm in this specification. Note that the conversion from transmittance to internal transmittance is performed using the following formula, assuming that the reflection loss R on the front and back surfaces of the glass is 0.0454, respectively.
Internal transmittance = external transmittance / {100×(1-R) ² }

When used as a near-infrared absorption cut filter, the glass according to this embodiment is required to have high absorption of light in the near-infrared region. Therefore, the transmittance of the above glass at a wavelength of 800 nm is preferably 30% or less, more preferably 25% or less, even more preferably 20% or less, even more preferably 15% or less, and most preferably 10% or less. In addition, the closer the transmittance is to 0%, the more preferable, but it is usually 0.01% or more.

The thickness of the glass according to this embodiment is preferably 0.03 to 1 mm. From the viewpoint of obtaining the strength necessary to prevent breakage during manufacture, transportation, installation into a solid-state imaging element, etc., the thickness is preferably 0.03 mm or more, more preferably 0.05 mm or more, even more preferably 0.07 mm or more, and particularly preferably 0.1 mm or more. Furthermore, from the viewpoint of responding to the miniaturization and thinning of devices and equipment incorporating glass, such as solid-state imaging elements, the thickness is preferably 1 mm or less, more preferably 0.8 mm or less, even more preferably 0.6 mm or less, particularly preferably 0.4 mm or less, and most preferably 0.3 mm or less.

The glass transition temperature (Tg) of the glass according to this embodiment is preferably 350 to 600°C. From the viewpoint of enhancing the stability of the glass, the glass transition temperature is preferably 350°C or higher, more preferably 375°C or higher, even more preferably 400°C or higher, and even more preferably 425°C or higher. From the viewpoint of suppressing an increase in the melting temperature of the glass, the glass transition temperature is preferably 600°C or lower, more preferably 575°C or lower, even more preferably 550°C or lower, even more preferably 525°C or lower, and even more preferably 500°C or lower.

<composition>
In the glass according to the present embodiment, phosphorus (P) is a network-forming component and a main component necessary for vitrification. It is also a component that enhances the absorbency of light in the near-infrared region.
The content of P ₂ O ₅ in the above glass in terms of mole percent based on oxide is 25% or more, preferably 25 to 80%, and more preferably 30 to 50%. Here, from the viewpoint of forming a network as much as possible to become glass and suitably absorbing light in the near infrared region, the content of P ₂ O ₅ is preferably 25% or more, more preferably 28% or more, even more preferably 30% or more, even more preferably 35% or more, particularly preferably 40% or more, and even more preferably 45% or more. In addition, from the viewpoint of suppressing a decrease in the transmittance of light in the visible region due to an excessively high melting temperature during the production of glass, the content of P ₂ O ₅ is preferably 80% or less, more preferably 75% or less, even more preferably 70% or less, even more preferably 65% or less, even more preferably 60% or less, and particularly preferably 50% or less.

The glass according to this embodiment contains a component that absorbs light in the near-infrared region, i.e., a near-infrared absorbing component, so that it can be suitably used in near-infrared absorption cut filters and the like. Here, the near-infrared absorbing component is a component whose maximum absorption wavelength is in the range of 700 to 1200 nm.

The total content of the near-infrared absorbing components, expressed in mole percent on an oxide basis, is 0.5% or more, and preferably 0.5 to 30%. From the viewpoint of increasing the absorbency of light in the near-infrared region, the total content is preferably 0.5% or more, more preferably 1% or more, even more preferably 5% or more, and even more preferably 10% or more. From the viewpoint of preventing the precipitation of devitrification inclusions in the glass, the total content is preferably 30% or less, more preferably 26% or less, even more preferably 22% or less, and even more preferably 18% or less.

Examples of the near infrared absorbing component include Cu, Fe, V, etc., and one of these may be used alone or two or more of them may be used in combination.
That is, the glass according to this embodiment preferably contains one or more elements selected from the group consisting of Cu, Fe, and V as a near-infrared absorbing component, and more preferably contains at least Cu from the viewpoint of efficiently absorbing light in the near-infrared region.

When the glass according to this embodiment contains Cu as a near-infrared absorbing component, the CuO content expressed in mole percent on an oxide basis is preferably 0.5% or more, and more preferably 0.5 to 30%. From the viewpoint of efficiently absorbing light in the near-infrared range and from the viewpoint of increasing the strength and stability of the glass, the CuO content is preferably 0.5% or more, more preferably 1% or more, even more preferably 5% or more, and even more preferably 10% or more. Furthermore, from the viewpoint of suppressing a decrease in the visible transmittance of the glass, the CuO content is preferably 30% or less, more preferably 26% or less, even more preferably 22% or less, and even more preferably 18% or less.

In the glass according to the present embodiment, depending on the glass composition, the ratio represented by {[H ⁺ _A ]/[H ⁺ _B ]} becomes 2 or less without post-treatment, but there are cases where the ratio does not become 2 or less without post-treatment. Even in such a case, the ratio can be made 2 or less by the post-treatment. Moreover, even in a composition where the ratio becomes 2 or less without post-treatment, the ratio can be made smaller by the post-treatment.

From the viewpoint of making it easier to obtain the effects of the above-mentioned post-treatment, the glass according to this embodiment preferably contains one or more elements selected from the group consisting of Ti, W, and Nb.
In this case, the total content of TiO ₂ , WO ₃ and Nb ₂ O ₅ is preferably 5% or more, and more preferably 5 to 30%, expressed in mole % on an oxide basis. From the viewpoint of more easily obtaining the effects of the post-treatment, the total content is preferably 5% or more, more preferably 7.5% or more, even more preferably 10% or more, and even more preferably 12.5% or more. From the viewpoint of suppressing a decrease in the visible transmittance of the glass, the total content is preferably 30% or less, more preferably 25% or less, and even more preferably 20% or less.

More specifically, the composition of the glass according to this embodiment preferably satisfies the following contents in mole percent on an oxide basis.
_P2O5 : _25-80 %,
Al ₂ O ₃ : 1 to 20%,
ΣR ₂ O: 0 to 35% (wherein R represents Li, Na, K, Rb, and Cs);
ΣR′O: 0 to 30% (wherein R′ represents Mg, Ca, Sr, Ba and Zn), and CuO: 0.5 to 30%.
The ΣR ₂ O means the total content of Li ₂ O, Na ₂ O, K ₂ O, Cs ₂ O, and Rb ₂ O, and the ΣR′O means the total content of MgO, CaO, SrO, BaO, and ZnO.

In particular, in the case of making a glass in which the ratio represented by {[H ⁺ _A ]/[H ⁺ _B ]} is 2 or less, regardless of the presence or absence of post-treatment, it is preferable that the content expressed in mol % on an oxide basis satisfies the following:
_P2O5 : _30-50 %,
Al ₂ O ₃ : 1 to 10%,
ΣR ₂ O: 10 to 35% (wherein R represents Li, Na, K, Rb, and Cs);
ΣR′O: 0 to 10% (wherein R′ means Mg, Ca, Sr, Ba and Zn),
CuO: 1-15%,
_TiO2 : 0-10%,
The content of WO ₃ is 0 to 10%, and the content of Nb ₂ O ₅ is 0 to 10%.
The ΣR ₂ O means the total content of Li ₂ O, Na ₂ O, K ₂ O, Cs ₂ O, and Rb ₂ O, and the ΣR′O means the total content of MgO, CaO, SrO, BaO, and ZnO.

The P ₂ O ₅ , CuO which is one aspect of the near infrared absorbing component, and the total of TiO ₂ , WO ₃ and Nb ₂ O ₅ are as described above. The rest of the composition will be described below.

Al ₂ O ₃ is a component for improving weather resistance. The content of Al ₂ O ₃ is preferably 1 to 20 mol%, more preferably 1 to 10 mol%. Here, from the viewpoint of improving the weather resistance of the glass, the content of Al ₂ O ₃ is preferably 1 mol% or more, more preferably 2 mol% or more, and even more preferably 3 mol% or more. In addition, from the viewpoint of suppressing the decrease in absorbency in the near infrared region and the decrease in transmittance of light in the visible region due to the melting temperature becoming too high when producing the glass, the content of Al ₂ O ₃ is preferably 20 mol% or less, more preferably 17 mol% or less, even more preferably 15 mol% or less, and even more preferably 10 mol% or less.

_R2O is a component that lowers the melting temperature of glass. R represents Li, Na, K, Rb, and Cs, and _ΣR2O represents the total amount of _Li2O , _Na2O , K2O, _{Rb2O , and Cs2O .}
ΣR ₂ O is preferably 0 to 35 mol %, and more preferably 10 to 35 mol %. From the viewpoint of preferably obtaining the above-mentioned effects of R ₂ O, when R ₂ O is contained, ΣR ₂ O is preferably 10 mol % or more, more preferably 12 mol % or more, and even more preferably 14 mol % or more. From the viewpoint of suppressing glass instability, ΣR ₂ O is preferably 35 mol % or less, more preferably 33 mol % or less, and even more preferably 32 mol % or less.

As R ₂ O, it is preferable to contain at least one selected from the group consisting of Li ₂ O, Na ₂ O, and K ₂ O, it is more preferable to contain at least one of Li ₂ O and Na ₂ O, and it is even more preferable to contain Li ₂ O. It is also more preferable to contain Li ₂ O and Na ₂ O.

When Li ₂ O is included as R ₂ O, the content of Li ₂ O is preferably 0.1 to 15 mol %. Here, from the viewpoint of suitably obtaining the above-mentioned effect of Li ₂ O, the content of Li ₂ O when included is preferably 0.1 mol % or more, more preferably 2 mol % or more, even more preferably 4 mol % or more, and even more preferably 6 mol % or more. Also, from the viewpoint of suppressing glass instability, the content of Li ₂ O is preferably 15 mol % or less, more preferably 14 mol % or less, even more preferably 13 mol % or less, and even more preferably 12 mol % or less.

When Na ₂ O is included as R ₂ O, the content of Na ₂ O is preferably 0.1 to 30 mol %. Here, from the viewpoint of suitably obtaining the above-mentioned effect of Na ₂ O, the content of Na ₂ O when included is preferably 0.1 mol % or more, more preferably 5 mol % or more, even more preferably 10 mol % or more, and even more preferably 15 mol % or more. Also, from the viewpoint of suppressing glass instability, the content of Na ₂ O is preferably 30 mol % or less, more preferably 28 mol % or less, even more preferably 26 mol % or less, and even more preferably 24 mol % or less.

When K ₂ O is included as R ₂ O, the content of K ₂ O is preferably 0.1 to 20 mol %. Here, from the viewpoint of suitably obtaining the above-mentioned effects of K ₂ O, the content of K ₂ O when included is preferably 0.1 mol % or more, more preferably 4 mol % or more, further preferably 8 mol % or more, and even more preferably 10 mol % or more. Also, from the viewpoint of suppressing glass instability, the content of K ₂ O is preferably 20 mol % or less, more preferably 18 mol % or less, further preferably 16 mol % or less, and even more preferably 14 mol % or less.

R'O is a component for increasing the stability of glass and lowering the melting temperature of glass. R' means Mg, Ca, Sr, Ba, and Zn, and ΣR'O means the total amount of MgO, CaO, SrO, BaO, and ZnO.
ΣR'O is preferably 0 to 30 mol%, and more preferably 0 to 10 mol%. From the viewpoint of obtaining the above-mentioned effect of R'O, ΣR'O in the case where R'O is contained is preferably 2 mol% or more, more preferably 4 mol% or more, and even more preferably 6 mol% or more. From the viewpoint of suppressing the glass from becoming unstable, ΣR'O is preferably 30 mol% or less, more preferably 20 mol% or less, and even more preferably 10 mol% or less.

Among the R'O components, MgO, CaO, and SrO have the effect of increasing the stability of the glass, but are also components that reduce the absorbency of light in the near infrared region. The total content of these components is preferably 20 mol% or less, more preferably 15 mol% or less, and even more preferably 10 mol% or less, and may not be present.

Among R'O, BaO has the effect of lowering the melting temperature of the glass, but it is also a component that makes the glass unstable and reduces the absorbency of light in the near infrared region. The BaO content is preferably 0 to 20 mol%. Here, from the viewpoint of suitably lowering the melting temperature of the glass, the BaO content is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 15 mol% or more. Furthermore, from the viewpoint of preventing the glass from becoming unstable, the BaO content is preferably 20 mol% or less, more preferably 10 mol% or less, and even more preferably 5 mol% or less, and may not be contained.

Among R'O, ZnO has the effect of lowering the melting temperature of glass, but is also a component that reduces the solubility of glass. The ZnO content is preferably 0 to 20 mol%. From the viewpoint of suitably lowering the melting temperature of glass, the ZnO content is preferably 1 mol% or more, more preferably 3 mol% or more, and even more preferably 5 mol% or more. Furthermore, from the viewpoint of maintaining the solubility of glass, the BaO content is preferably 20 mol% or less, more preferably 15 mol% or less, and even more preferably 10 mol% or less.

The glass according to this embodiment preferably contains CuO as a near-infrared absorbing component, but may contain a near-infrared absorbing component other than CuO, such as Fe ₂ O ₃ or V ₂ O ₅ .
The total content of the near-infrared absorbing components including CuO is preferably 0.5 to 30 mol%. Here, from the viewpoint of increasing the absorbency of light in the near-infrared region, the total content is preferably 0.5 mol% or more, more preferably 5 mol% or more, even more preferably 7 mol% or more, and even more preferably 10 mol% or more. Also, from the viewpoint of suppressing a decrease in light transmittance in the visible region, the total content is preferably 30 mol% or less, more preferably 27 mol% or less, even more preferably 25 mol% or less, and even more preferably 23 mol% or less.

As a near infrared absorbing component other than CuO, the content of Fe ₂ O ₃ is preferably 0.5 to 30 mol%. Here, from the viewpoint of increasing the absorbency of light in the near infrared region, the content of Fe ₂ O ₃ is preferably 0.5 mol% or more, more preferably 5 mol% or more, even more preferably 7 mol% or more, and even more preferably 10 mol% or more. In addition, from the viewpoint of suppressing the decrease in light transmittance in the visible region due to an increase in the proportion of Fe ³⁺ present, the content of Fe ₂ O ₃ is preferably 30 mol% or less, more preferably 27 mol% or less, even more preferably 25 mol% or less, and even more preferably 23 mol% or less.
From the viewpoint of efficiently increasing the absorbency of light in the near-infrared region, the content of CuO, which is a near-infrared absorbing component, is preferably greater than the content of at least one of Fe ₂ O ₃ and V ₂ O ₅ , and more preferably greater than the contents of both Fe ₂ O ₃ and V ₂ O ₅ .

In addition to the above, the glass according to this embodiment preferably contains one or more selected from the group consisting of TiO ₂ , WO ₃ and Nb ₂ O _5, from the viewpoint of suitably obtaining the effect of reducing the ratio represented by {[H ⁺ _A ]/[H ⁺ _B ]} by post-treatment.

The content of _TiO2 is preferably 0 to 10 mol%. Here, from the viewpoint of making it easier to obtain the effects of the above-mentioned post-treatment, the content of _TiO2 is more preferably 1 mol% or more, even more preferably 2 mol% or more, and even more preferably 3 mol% or more. Also, from the viewpoint of suppressing a decrease in the transmittance in the visible range, the content of _TiO2 is preferably 10 mol% or less, more preferably 9 mol% or less, even more preferably 8 mol% or less, and even more preferably 7 mol% or less.

The content of _WO3 is preferably 0 to 10 mol%. Here, from the viewpoint of making it easier to obtain the effects of the post-treatment, the content of _WO3 is more preferably 1 mol% or more, even more preferably 2 mol% or more, and even more preferably 3 mol% or more. Also, from the viewpoint of suppressing a decrease in the transmittance in the visible range, the content of _WO3 is preferably 10 mol% or less, more preferably 9 mol% or less, even more preferably 8 mol% or less, and even more preferably 7 mol% or less.

The content of Nb ₂ O ₅ is preferably 0 to 10 mol %. From the viewpoint of more easily obtaining the effect of the post-treatment, the content of Nb ₂ O ₅ is more preferably 1 mol % or more, even more preferably 2 mol % or more, and even more preferably 3 mol % or more. From the viewpoint of suppressing a decrease in the transmittance in the visible range, the content of Nb ₂ O ₅ is preferably 10 mol % or less, more preferably 9 mol % or less, even more preferably 8 mol % or less, and even more preferably 7 mol % or less.

The glass according to this embodiment may contain, in addition to P ₂ O ₅ , glass network-forming components such as B ₂ O ₃ and SiO ₂ .
The total content of P ₂ O ₅ , B ₂ O ₃ and SiO ₂ is preferably 25 to 90 mol %. From the viewpoint of suppressing a decrease in the strength of the glass, the total content is more preferably 30 mol % or more, even more preferably 35 mol % or more, and even more preferably 40 mol % or more. From the viewpoint of suppressing an increase in the melting temperature of the glass, the total content is preferably 90 mol % or less, more preferably 80 mol % or less, even more preferably 70 mol % or less, and even more preferably 60 mol % or less.

The content of B ₂ O ₃ is preferably 0 to 30 mol %. From the viewpoint of suppressing a decrease in glass strength, the content of B ₂ O ₃ is more preferably 1 mol % or more, even more preferably 5 mol % or more, and even more preferably 10 mol % or more. From the viewpoint of suppressing a decrease in weather resistance of the glass, the content of B ₂ O ₃ is preferably 30 mol % or less, more preferably 25 mol % or less, even more preferably 20 mol % or less, and even more preferably 15 mol % or less.

The content of SiO ₂ is preferably 0 to 30 mol%. Here, from the viewpoint of improving the weather resistance of the glass, the content of SiO ₂ is more preferably 0.5 mol% or more, even more preferably 1 mol% or more, and even more preferably 2 mol% or more. Also, from the viewpoint of suppressing an increase in the melting temperature of the glass, the content of SiO ₂ is preferably 30 mol% or less, more preferably 25 mol% or less, even more preferably 20 mol% or less, even more preferably 15 mol% or less, and may not be contained.

The glass according to the present embodiment may be a glass containing fluoride, which is called fluorophosphate glass among phosphate glasses. Fluorophosphate glass exhibits high weather resistance due to the inclusion of fluoride, but when the glass has the same composition, the weather resistance can be further improved by changing the ratio represented by {[H ⁺ _A ]/[H ⁺ _B ]} from more than 2 to 2 or less.
As described above, fluorophosphate glass is a glass with high weather resistance to begin with. Therefore, the degree of improvement in weather resistance by making the above ratio 2 or less is remarkable in the case of glass that does not contain fluoride. Even in the case of glass that contains fluoride but the content is so small that it does not contribute to improving weather resistance, the degree of improvement in weather resistance by making the above ratio 2 or less is remarkable.

From the above viewpoints, and from the viewpoint of environmental conservation, the F content in the glass according to this embodiment, expressed as mol %, is preferably 7% or less, more preferably 5% or less, even more preferably 3% or less, even more preferably 2% or less, and particularly preferably 1% or less, and may not be contained at all. Note that the F content in the glass according to this embodiment is expressed as an exclusive percentage, and is not included in the total content of the glass components expressed on an oxide basis. In other words, the above-mentioned exclusive percentage means the F content when the glass composition other than F contained in the glass is taken as 100 mol %.

In addition to the above components, the glass according to this embodiment may contain other components within a range that does not impair the effects of the present invention. Examples of other components include GeO ₂ , ZrO ₂ , SnO ₂ , CeO ₂ , Y ₂ O ₃ , La ₂ O ₃ , Gd ₂ O ₃ , and Yb ₂ O ₃ . When these other components are contained, the total content is preferably 0 to 5 mol%. Here, from the viewpoint of obtaining the effects of the other components in a favorable manner, the total content is more preferably 0.1 mol% or more, and even more preferably 0.2 mol% or more. In addition, from the viewpoint of suppressing deterioration of the absorbency of light in the near infrared region, the total content is preferably 5 mol% or less, more preferably 4 mol% or less, and even more preferably 3 mol% or less.

Moreover, it is preferable that the glass according to this embodiment contains substantially no PbO, As ₂ O ₃ , or GdF ₃ .
PbO is a component that reduces the viscosity of glass and improves manufacturing workability. Also, _As2O3 is a component that acts as an excellent clarifier that can generate clarified gas in a wide temperature range. However, since _both PbO and _As2O3 are environmentally hazardous substances, it is preferable to avoid _their inclusion as much as possible.
Although _GdF3 is a component that stabilizes glass, the raw material is relatively expensive, which leads to increased costs, so it is preferable to avoid its inclusion as much as possible.
With regard to the above three components, "substantially not contained" means that they are not intentionally used as raw materials, and the content of each component in the glass is 0.1 mol % or less.

Near-infrared absorption cut filter
The near-infrared absorption cut filter according to this embodiment includes the glass described above in "Glass." The preferred aspects of this glass are also similar to the preferred aspects described above in "Glass."

The near-infrared absorption cut filter according to this embodiment may have an optical multilayer film provided on at least one main surface of glass formed into a predetermined shape.
Examples of optical multilayer films include IR cut films, UV/IR cut films (films that reflect ultraviolet and near infrared rays), UV cut films, anti-reflection films, etc. The optical multilayer film can be formed by a conventionally known method, such as a vapor deposition method, a sputtering method, etc.

An adhesion-strengthening film may be provided between the glass and the optical multilayer film, which improves the adhesion between the glass and the optical multilayer film and prevents the film from peeling off.
Examples of the adhesion-strengthening film include silicon oxide (SiO ₂ ), titanium oxide (TiO ₂ ), lanthanum titanate (La ₂ Ti ₂ O ₇ ), aluminum oxide (Al ₂ O ₃ ), a mixture of aluminum oxide and zirconium oxide (ZrO ₂ ), magnesium fluoride (MgF ₂ ), calcium fluoride (CaF ₂ ), strontium fluoride (SrF ₂ ), and fluorosilicone.
Substances containing fluorine or oxygen have higher adhesion, and magnesium fluoride and titanium oxide are particularly preferred because they have higher adhesion to glass and films.
The adhesion-strengthening film may be a single layer or may be two or more layers. In the case of two or more layers, a combination of a plurality of materials may be used.

The near-infrared absorption cut filter according to this embodiment may have an absorption layer containing a near-infrared absorbing material having a maximum absorption wavelength in the near-infrared range on at least one of the main surfaces of the glass according to this embodiment. By adopting such a configuration, it is possible to obtain an optical filter with a lower transmittance of light in the near-infrared range.

The near-infrared absorption cut filter according to this embodiment is preferably made of a transparent resin selected from an acrylic resin, an epoxy resin, an ene-thiol resin, a polycarbonate resin, a polyether resin, a polyarylate resin, a polysulfone resin, a polyethersulfone resin, a polyparaphenylene resin, a polyarylene ether phosphine oxide resin, a polyimide resin, a polyamideimide resin, a polyolefin resin, a cyclic olefin resin, and a polyester resin, and is preferably made of one of these resins alone or a mixture of two or more of these resins, to which a near-infrared absorbing dye is added and contained in the absorption layer.
As the near-infrared absorbing dye, it is preferable to use a near-infrared absorbing material made of at least one dye selected from the group consisting of squarylium dyes, phthalocyanine dyes, cyanine dyes and diimmonium dyes.

<<Solid-state imaging element>>
The solid-state imaging device according to this embodiment includes the near-infrared absorption cut filter described above in "Near-infrared absorption cut filter." Preferred aspects of this near-infrared absorption cut filter are also similar to the preferred aspects described above in "Near-infrared absorption cut filter."

The solid-state imaging element according to this embodiment includes an imaging lens in addition to the near-infrared absorption cut filter.

The solid-state imaging element converts the input light into an electrical signal and outputs it to an image signal processing circuit. Examples of solid-state imaging elements include a Charge Coupled Device (CCD) image sensor and a Complementary Metal Oxide Semiconductor (CMOS) image sensor.

The imaging device using the solid-state imaging element may further include an imaging lens, and the near-infrared absorbing cut filter may be disposed between the imaging lens and the solid-state imaging element.
The near-infrared absorbing cut filter may be provided separately from the solid-state imaging element, and may be directly attached to an imaging lens or the like via an adhesive layer, for example.

<Glass manufacturing method>
One embodiment of the method for producing the glass described above in the section "Glass" will be described below. However, the production method is not limited to the following embodiment.

The method for producing glass according to this embodiment includes the following steps.
Step 1: A step of weighing and mixing glass raw materials to obtain a raw material mixture. Step 2: A step of heating and melting the raw material mixture obtained in step 1. Step 3: A step of forming the melt obtained in step 2.

When the ratio represented by {[H ⁺ _A ]/[H ⁺ _B ]} of the glass obtained in the above step 3 does not satisfy 2 or less, it is preferable to further include a step 4 of post-treatment.

<Step 1>
Step 1 may be carried out using a conventionally known material and employing a conventionally known method.
For example, the content of the resulting glass in mole percent based on oxides is:
_P2O5 : _30-50 %,
Al ₂ O ₃ : 1 to 10%,
ΣR ₂ O: 10-35%,
ΣR'O: 0~10%,
CuO: 1-15%,
_TiO2 : 0-10%,
It is preferable to obtain a raw material mixture that satisfies WO ₃ : 0-10% and Nb ₂ O ₅ : 0-10%, because this makes it easier to obtain a glass in which the ratio represented by {[H ⁺ _A ]/[H ⁺ _B ]} is 2 or less without going through step 4.

<Step 2>
The heating and melting conditions in step 2 can also employ conventionally known methods and conditions, but the heating temperature is preferably 700 to 1450° C. Here, from the viewpoint of suppressing the occurrence of devitrification and from the viewpoint of shortening the production time, the heating temperature is preferably 700° C. or higher, more preferably 800° C. or higher, even more preferably 900° C. or higher, and even more preferably 1000° C. or higher. In addition, from the viewpoint of suppressing a decrease in the transmittance of light in the visible range, the heating temperature is preferably 1450° C. or lower, more preferably 1400° C. or lower, even more preferably 1350° C. or lower, and even more preferably 1300° C. or lower.

<Step 3>
Step 3 is a step of shaping the melt obtained in step 2. If necessary, an oxidizing agent may be added or clarification may be performed between steps 2 and 3.
Additives and fining agents include, for example, nitrate and sulfate compounds having glass-forming cations.
The oxidizing agent has the effect of increasing the proportion of Cu ²⁺ ions in the total amount of Cu in the glass, thereby improving the transmittance of light in the visible range and improving the absorbance of light in the near-infrared range.

The amount of nitrate compounds or sulfate compounds added is preferably 0.5 to 10 mass% based on the raw material mixture in terms of the total amount added. From the viewpoint of further improving the transmittance of light in the visible range, the amount added is preferably 0.5 mass% or more, more preferably 1 mass% or more, and even more preferably 3 mass% or more. Also, from the viewpoint of the effect of the addition reaching a plateau and from the viewpoint of glass formability, the amount added is preferably 10 mass% or less, more preferably 8 mass% or less, and even more preferably 6 mass% or less.

Examples of nitrate compounds include Al( _NO3 ) ₃ , _LiNO3 , _NaNO3 , _KNO3 , Ca( _NO3 ) ₂ , Sr( _NO3 ) ₂ , Ba( _NO3 ) ₂ , Zn( _NO3 ) ₂ , and Cu( _NO3 ) ₂ .
Examples of sulfate compounds include _{Al2 ( SO4} ) _3.16H2O , _Li2SO4 , _{Na2SO4 , K2SO4} , _CaSO4 , _SrSO4 , _BaSO4 , _ZnSO4 , _{and CuSO4 .}

<Step 4>
Step 4 is optional. However, when the ratio represented by {[H ⁺ _A ]/[H ⁺ _B ]} of the glass obtained in step 3 does not satisfy 2 or less, it is preferable to further include a step of performing a post-treatment as step 4.
The post-treatment method may be any method that reduces the H ⁺ concentration [H ⁺ _A ] on the glass surface, and examples thereof include surface polishing treatment, heat treatment, chemical treatment, gas treatment, ion exchange treatment, and plasma treatment.
The heat treatment is preferably carried out at a temperature near the glass transition temperature (Tg) of the glass, and more preferably at a temperature in the range of (Tg±100)°C.
The chemical used in the chemical treatment can be appropriately selected from acidic, neutral, and alkaline solutions to the extent that the glass surface is not deteriorated.

The present invention will be specifically explained below with reference to examples, but the present invention is not limited thereto. Examples 1 to 4 and Examples 6 to 16 are examples, and Example 5 is a comparative example.

Test Example
Example 1:
Glass raw materials were weighed and mixed to obtain a raw material mixture having the composition shown in Table 1. The raw material mixture was then heated and melted at 1100°C for 2 hours. The melt obtained was clarified and stirred, then poured into a mold and slowly cooled. Next, a glass having a size of 40 mm x 30 mm and a thickness of 0.21 mm was obtained by polishing. The glass transition temperature of this glass was 450°C.
Further, as a post-treatment, a heat treatment was carried out in an air atmosphere at 450° C. for 12 hours.
In addition, "-" in "Composition (mol %)" in Table 1 means that it was not intentionally added as a glass raw material. The same applies to Tables 2 and 3.

Example 2:
Glass was obtained in the same manner as in Example 1, except that the obtained glass was subjected to a heat treatment at 450° C. for 12 hours in a nitrogen atmosphere as a post-treatment.

Example 3:
A glass was obtained in the same manner as in Example 1, except that the obtained glass was not subjected to any post-treatment.

Example 4:
Glass raw materials were weighed and mixed to obtain a raw material mixture having the composition shown in Table 1. The raw material mixture was then heated and melted at 1050°C for 2 hours. The melt obtained was clarified and stirred, then poured into a mold and slowly cooled. Next, a glass having a size of 40 mm x 30 mm and a thickness of 0.21 mm was obtained by polishing. The glass transition temperature of this glass was 460°C.
Further, as a post-treatment, a heat treatment was carried out in an air atmosphere at 450° C. for 12 hours.

Example 5:
A glass was obtained in the same manner as in Example 4, except that no post-treatment was carried out.

Example 6:
Glass raw materials were weighed and mixed to obtain a raw material mixture having the composition shown in Table 2. The raw material mixture was then heated and melted at 1250° C. for 2 hours. The melt obtained was clarified and stirred, then poured into a mold and slowly cooled. Next, a glass having a size of 40 mm×30 mm and a thickness of 0.21 mm was obtained by polishing. The glass transition temperature of this glass was not measured.

Example 7:
Glass raw materials were weighed and mixed to obtain a raw material mixture having the composition shown in Table 2. The raw material mixture was then heated and melted at 1200°C for 2 hours. The melt obtained was clarified and stirred, then poured into a mold and slowly cooled. Next, a glass having a size of 40 mm x 30 mm and a thickness of 0.21 mm was obtained by polishing. The glass transition temperature of this glass was 433°C.
Further, as a post-treatment, a heat treatment was carried out in an air atmosphere at 425° C. for 24 hours.

Example 8:
A glass was obtained in the same manner as in Example 7, except that the obtained glass was subjected to a heat treatment at 440° C. for 48 hours in an air atmosphere as a post-treatment.

Example 9:
Glass raw materials were weighed and mixed to obtain a raw material mixture having the composition shown in Table 2. The raw material mixture was then heated and melted at 1200°C for 2 hours. The melt obtained was clarified and stirred, then poured into a mold and slowly cooled. Next, a glass having a size of 40 mm x 30 mm and a thickness of 0.21 mm was obtained by polishing. The glass transition temperature of this glass was 438°C.
Further, as a post-treatment, a heat treatment was carried out in an air atmosphere at 425° C. for 24 hours.

Example 10:
A glass was obtained in the same manner as in Example 9, except that no post-treatment was carried out.

Example 11:
Glass raw materials were weighed and mixed to obtain a raw material mixture having the composition shown in Table 3. The raw material mixture was then heated and melted at 1200°C for 2 hours. The melt obtained was clarified and stirred, then poured into a mold and slowly cooled. Next, a glass having a size of 40 mm x 30 mm and a thickness of 0.21 mm was obtained by polishing. The glass transition temperature of this glass was 433°C.
Further, as a post-treatment, a heat treatment was carried out in an air atmosphere at 405° C. for 24 hours.

Example 12
A glass was obtained in the same manner as in Example 11, except that the obtained glass was subjected to a heat treatment at 420° C. for 48 hours in an air atmosphere as a post-treatment.

Example 13
Glass raw materials were weighed and mixed to obtain a raw material mixture having the composition shown in Table 3. The raw material mixture was then heated and melted at 1200°C for 2 hours. The melt obtained was clarified and stirred, then poured into a mold and slowly cooled. Next, a glass having a size of 40 mm x 30 mm and a thickness of 0.21 mm was obtained by polishing. The glass transition temperature of this glass was 401°C.
Further, as a post-treatment, a heat treatment was carried out in an air atmosphere at 390° C. for 24 hours.

Example 14:
Glass raw materials were weighed and mixed to obtain a raw material mixture having the composition shown in Table 3. The raw material mixture was then heated and melted at 1200°C for 2 hours. The melt obtained was clarified and stirred, then poured into a mold and slowly cooled. Next, a glass having a size of 40 mm x 30 mm and a thickness of 0.21 mm was obtained by polishing. The glass transition temperature of this glass was 399°C.
Further, as a post-treatment, a heat treatment was carried out in an air atmosphere at 404° C. for 48 hours.

Example 15:
Glass raw materials were weighed and mixed to obtain a raw material mixture having the composition shown in Table 3. The raw material mixture was then heated and melted at 1300°C for 2 hours. The melt obtained was clarified and stirred, then poured into a mold and slowly cooled. Next, a glass having a size of 40 mm x 30 mm and a thickness of 0.21 mm was obtained by polishing. The glass transition temperature of this glass was 408°C.
Further, as a post-treatment, a heat treatment was carried out in an air atmosphere at 378° C. for 48 hours.

Example 16:
A glass was obtained in the same manner as in Example 15, except that no post-treatment was carried out.

"evaluation"
<[H ⁺ _A ]/[H ⁺ _B ]>
The H ⁺ concentration (cps) from the surface of the glass to a depth of 20 μm was measured for the obtained glass using a secondary ion mass spectrometer (ADEPT1010, manufactured by ULVAC-PHI, Inc.). The measurement conditions were as follows. Measurement conditions [SIMS measurement conditions] Primary ion species: Cs+ Primary ion acceleration voltage: 5 kV Primary ion current value: 500 nA Primary ion incidence angle: 60° with respect to the normal line of the sample surface Primary ion raster size: 300 × 300 μm ² Secondary ion polarity: negative Secondary ion detection area: 60 × 60 μm ² (4% of the primary ion raster size) ESA Input Lens: 0 Use of neutralization gun: Yes Method of converting the horizontal axis from sputtering time to depth: Analysis The depth of the crater is measured using a stylus surface profiler (Dektak150, manufactured by Veeco), and the sputtering rate of the primary ions is obtained. Using this sputtering rate, the horizontal axis is converted from sputtering time to depth. Field Axis Potential during 1H-detection: The optimal value may vary depending on the device. The operator should carefully set the value so that the background is sufficiently cut.

The curves obtained by the above measurements were approximated with a sigmoid curve to determine the H ⁺ concentration [H ⁺ _A ] (cps) on the surface of the glass and the H ⁺ concentration [H ⁺ _B ] (cps) at a depth of 100 μm from the surface of the glass. The results are shown in Tables 1 to 3.

<β-OH value>
The transmittance of the obtained glass at 400 cm ^-1 to 4000 cm ^-1 was measured using a Fourier transform infrared spectrometer (Nic-plan/Nicolet 6700, manufactured by Thermo Fisher Scientific). The resolution was 2 cm ^-1 , the number of accumulations was 16, and the detector was a TGS detector. When the maximum value of the transmittance at 3650 cm ^-1 to 4000 cm ^-1 was T ₀ , the transmittance at 3550 cm ^-1 was T ₁ , and the thickness of the glass was d (mm), the value represented by the following formula was defined as the β-OH value.
β-OH value = -(1/d)・(log ₁₀ (T ₁ /T ₀ ))
The obtained β-OH values are shown in Tables 1 to 3.

<Transmittance>
The internal transmittance of the obtained glass in the wavelength range of 400 to 1200 nm was measured using a spectrophotometer (V-570, manufactured by JASCO Corporation). Then, based on the above-mentioned formula T _i2 = T _i1 ^t2/t1 , it was converted into the transmittance when the glass thickness was 0.2 mm. The results of the transmittance at wavelengths of 550 nm, 800 nm, and 1200 nm are shown in Tables 1 to 3.

Weather resistance
The obtained glass was left to stand for 100 hours in an environment of 85°C and 85% RH, and the weather resistance was evaluated by visually checking for any changes in appearance. Specifically, glass surfaces with little deterioration after the test were rated as "good", and glass components were eluted onto the surface, causing dripping, etc., and the degree of deterioration was evaluated as "poor". If the glass was rated as "good", the weather resistance was judged to be good.
Thereafter, the diffuse transmittance and the total light transmittance were measured using a haze meter (NDH5000, manufactured by Nippon Denshoku Industries Co., Ltd.). The value expressed as [diffuse transmittance/total light transmittance] was calculated as Haze (%). If the Haze value is 15% or less, it can be judged that the weather resistance is good, and the smaller the value, the more preferable.
The obtained results of the weather resistance evaluation are shown in Tables 1 to 3. In Tables 2 and 3, those for which the haze value was not measured are indicated as "no data."

From the above results, it has been found that in glass containing phosphorus and a near-infrared absorbing component, when the ratio represented by {[H ⁺ _A ]/[H ⁺ _B ]} is 2 or less, the glass undergoes little degradation under high temperature and high humidity conditions, the haze value is small, and the weather resistance is improved.
It was also found that even for glass in which the ratio represented by {[H ⁺ _A ]/[H ⁺ _B ]} exceeds 2, the weather resistance can be improved by performing post-treatment to set said ratio to 2 or less. Furthermore, when post-treatment is performed on glass having a composition in which the ratio represented by {[H ⁺ _A ]/[H ⁺ _B ]} is 2 or less, said ratio becomes even smaller, and not only the weather resistance but also the transmittance of visible light tends to improve.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application (Patent Application No. 2023-119934) filed on July 24, 2023, the contents of which are incorporated herein by reference.

Claims (14)

In mole percent based on oxide,
A glass containing 25% or more of _P2O5 and 0.5% or more of near- _infrared absorbing components in total,
A glass in which the ratio of the H ⁺ concentration [H ⁺ _A ] at the surface of the glass to the H ⁺ concentration [H ⁺ _B ] at a depth of 100 μm from the surface of the glass, expressed as {[H ⁺ _A ]/[H ⁺ _B ]}, is 2 or less. 2. The glass of claim 1 having a β-OH value of 1 mm ⁻¹ or less. 2. The glass of claim 1, wherein the ratio represented by {[H ⁺ _A ]/[H ⁺ _B ]} is less than 1. The glass according to claim 1, which has a transmittance of 70% or more at a wavelength of 550 nm when converted to a thickness of 0.2 mm. The glass according to claim 1, which has a transmittance of 30% or less at a wavelength of 800 nm when converted to a thickness of 0.2 mm. The glass according to claim 1, containing one or more near-infrared absorbing components selected from the group consisting of Cu, Fe, and V. The near infrared absorbing component contains Cu,
The glass according to claim 1 , containing, in mole percent on an oxide basis, 0.5% or more of CuO. The glass according to claim 1, containing one or more elements selected from the group consisting of Ti, W, and Nb. The glass according to claim 8, containing, in mole percent on an oxide basis, _TiO2 , _{WO3, and Nb2O5} in a total amount of 5% or more. The content in mole percent based on oxide is:
_P2O5 : _25-80 %,
Al ₂ O ₃ : 1 to 20%,
ΣR ₂ O: 0 to 35% (wherein R represents Li, Na, K, Rb, and Cs);
ΣR′O: 0 to 30% (wherein R′ represents Mg, Ca, Sr, Ba, and Zn), and CuO: 0.5 to 30%;
The ΣR ₂ O means the total content of Li ₂ O, Na ₂ O, K ₂ O, Cs ₂ O, and Rb ₂ O;
The glass according to claim 1 , wherein the ΣR′O represents the total content of MgO, CaO, SrO, BaO, and ZnO. The content in mole percent based on oxide is:
_P2O5 : _30-50 %,
Al ₂ O ₃ : 1 to 10%,
ΣR ₂ O: 10 to 35% (wherein R represents Li, Na, K, Rb, and Cs);
ΣR′O: 0 to 10% (wherein R′ means Mg, Ca, Sr, Ba and Zn),
CuO: 1-15%,
_TiO2 : 0-10%,
WO ₃ : 0 to 10% and Nb ₂ O ₅ : 0 to 10% are satisfied;
The ΣR ₂ O means the total content of Li ₂ O, Na ₂ O, K ₂ O, Cs ₂ O, and Rb ₂ O;
The glass according to claim 1 , wherein the ΣR′O represents the total content of MgO, CaO, SrO, BaO, and ZnO. The glass according to claim 1, in which the F content, expressed as mole percent, is 7% or less. A near-infrared absorption cut filter made of the glass according to any one of claims 1 to 12. A solid-state imaging device comprising the near-infrared absorbing cut filter according to claim 13.