JP2018106171A - Near-infrared cut filter glass and near-infrared cut filter - Google Patents

Abstract

A near-infrared cut filter glass that is hard to be devitrified and can obtain desired optical characteristics even when the concentration of a Cu component in the glass increases as the glass becomes thinner, and a near-infrared cut using the same The purpose is to provide a filter.
SOLUTION: P, F, O, Cu are contained as essential components, Mg is not substantially contained, and content of Ba ²⁺ in cation% / ΣR ²⁺ (ΣR ²⁺ is Ba ²⁺ , Sr ²⁺ , Ca ^2+). Is a total amount of 0.05 to 0.2.
[Selection] Figure 1

Description

  The present invention relates to a near-infrared cut filter glass that is used in a color correction filter for a digital still camera, a color video camera, and the like, and is particularly excellent in light transmittance in the visible range, and a near-infrared cut filter using the same.

  A solid-state imaging device such as a CCD or CMOS used for a digital still camera or the like has spectral sensitivity ranging from the visible region to the near infrared region near 1200 nm. Therefore, since excellent color reproducibility cannot be obtained as it is, the visibility is corrected using a near-infrared cut filter glass to which a specific substance that absorbs infrared rays is added. As this near-infrared cut filter glass, an optical glass in which CuO is added to a fluorophosphate glass has been developed and used so that it selectively absorbs wavelengths in the near-infrared region and has high weather resistance. The composition of these glasses is disclosed in Patent Documents 1 to 4.

Japanese Patent Laid-Open No. 1-219037 JP 2004-83290 A JP 2004-137100 A International Publication No. 2015/156163

  Cameras and the like using a solid-state image sensor are becoming smaller and thinner. Accordingly, the imaging device and the equipment on which the imaging device is mounted are also required to be reduced in size and thickness. In the case of thinning a near infrared cut filter glass obtained by adding CuO to a fluorophosphate glass, it is necessary to increase the concentration of a Cu component that affects optical characteristics. However, when the concentration of the Cu component in the glass is increased, the optical characteristics on the near infrared side are desired, but the transmittance of light in the visible range is lowered.

  The present invention is a near-infrared cut filter glass that is difficult to devitrify and can obtain desired optical characteristics even when the concentration of a Cu component in the glass increases as the glass becomes thinner, and a near-infrared ray using the same The purpose is to provide a cut filter.

  As a result of intensive studies, the inventor did not substantially contain Mg in the fluorophosphate glass, and by making the content ratio of Ba, Ca, and Sr within a predetermined range, it is difficult to devitrify and transmit in the visible range. It has been found that a near infrared cut filter glass having a high rate can be obtained.

The near-infrared cut filter glass of the present invention contains P, F, O, and Cu as essential components, does not substantially contain Mg, and contains Ba ²⁺ in cation% / ΣR ²⁺ (ΣR ²⁺ is Ba ^2+). , Sr ²⁺ , Ca ²⁺ )) is 0.05 to 0.2.

In the near-infrared cut filter glass of the present invention, the Ca ²⁺ content / ΣR ²⁺ in cation% is preferably 0.35 to 0.7, and the Sr ²⁺ content / ΣR ²⁺ is preferably 0.2 to 0.45.

The near-infrared cut filter glass of the present invention has a cation% of P ⁵⁺ of 20 to 50%, Al ³⁺ of 5 to 20%, and ΣR ′ ⁺ (ΣR ′ ⁺ is at least one of Li ⁺ , Na ⁺ and K ^+. of a total amount) 15-35%, the ^{Ca 2+} 3 to 15%, a ^{Sr 2+} 3 to 10%, the ^{Ba 2+} 0.1 to 10%, the ^{Cu 2+} 0.5 to 25%, anionic% It is preferable to contain 10 to 40% of F ⁻ and 60 to 90% of O ²⁻ .

The near-infrared cut filter glass of the present invention preferably contains 0.1 to 35% of Li ⁺ in cation%.

The near-infrared cut filter glass of the present invention preferably contains 0.1 to 35% of Na ⁺ in terms of cation%.

The near-infrared cut filter glass of the present invention preferably contains 0.1 to 35% of K ⁺ in cation%.

The near-infrared cut filter glass of the present invention preferably contains Zn ²⁺ 1 to 25% in terms of cation%.

  The near-infrared cut filter of the present invention has the near-infrared cut filter glass of the present invention and an optical multilayer film provided on at least one surface of the near-infrared cut filter glass, and the near-infrared cut filter glass and the above-mentioned It is preferable to have an adhesion enhancing film between the optical multilayer films.

  In the near-infrared cut filter of the present invention, it is preferable that the adhesion enhancing film contains fluorine and / or oxygen.

  In the near-infrared cut filter of the present invention, it is preferable that the adhesion enhancing film contains magnesium fluoride and / or titanium oxide.

  In the near-infrared cut filter of the present invention, the optical multilayer film is preferably selected from an IR cut film, a UV / IR cut film, a UV cut film, an antireflection film, and a combination thereof.

  According to the present invention, a near-infrared cut filter glass that can be melted at a low temperature and has a high light transmittance in the visible region and a near-infrared cut filter using the same can be obtained by being hard to devitrify. Further, according to the present invention, since the strength of the glass is high, it is easy to reduce the thickness.

The graph of the transmittance | permeability in the Example and comparative example of this invention is shown.

The near-infrared cut filter glass of the present invention (hereinafter also simply referred to as “glass”) contains P, F, O, and Cu as essential components, does not substantially contain Mg, and contains Ba ²⁺ in cation%. Content / ΣR ²⁺ (ΣR ²⁺ refers to the total amount of Ba ²⁺ , Sr ²⁺ , and Ca ²⁺ ) is 0.05 to 0.2.

  In this specification, “cation%” and “anion%” are units as follows. First, the constituent components of glass are divided into a cation component and an anion component. “Cation%” is a unit in which the content of each cation component is expressed as a mole percentage when the total content of all cation components contained in the glass is 100 mol%. “Anion%” is a unit in which the content of each anion component is expressed as a mole percentage when the total content of all anion components contained in the glass is 100 mol%.

  The glass of the present invention is a copper-containing fluorophosphate glass containing P, F, O, and Cu as essential components. If it is glass which has P as a main component, it has the effect of improving the cut property in the near infrared region. Moreover, weather resistance can be improved by containing F. Furthermore, Cu is contained in order to give near infrared cut property. Cu can color the glass blue and absorb infrared rays.

  Moreover, it is preferable that the glass of this invention does not contain Mg substantially. Mg is a component for increasing the strength of the glass. However, Mg tends to destabilize glass and deteriorate devitrification, and it is preferable not to contain it. Here, “substantially not containing” means not intentionally using as a raw material, and means that the Mg content in the near-infrared cut filter glass is 0.1% or less.

In the glass of the present invention, the content of Ba ²⁺ in cation% / ΣR ²⁺ (ΣR ²⁺ refers to the total amount of Ba ²⁺ , Sr ²⁺ , and Ca ²⁺ ) is 0.05 to 0.2. If it is less than 0.05, the weather resistance may deteriorate. Preferably it is 0.07 or more, More preferably, it is 0.09 or more. On the other hand, if it exceeds 0.2, the strength may decrease. Preferably it is 0.18 or less, More preferably, it is 0.16 or less.

In the glass of the present invention, the content of Ca ²⁺ in cation% / ΣR ²⁺ (ΣR ²⁺ refers to the total amount of Ba ²⁺ , Sr ²⁺ , and Ca ²⁺ ) is set to 0.35 to 0.7. If it is less than 0.35, the weather resistance may deteriorate. Preferably it is 0.37 or more, More preferably, it is 0.39 or more. If it exceeds 0.7, the strength may decrease. Preferably it is 0.68 or less, More preferably, it is 0.65 or less.

Further, the glass of the present invention has an Sr ²⁺ content in cation% / ΣR ²⁺ (ΣR ²⁺ means the total amount of Ba ²⁺ , Sr ²⁺ , and Ca ²⁺ ) of 0.2 to 0.45. If it is less than 0.2, the weather resistance may deteriorate. Preferably it is 0.23 or more, More preferably, it is 0.25 or more. On the other hand, if it exceeds 0.45, the strength may decrease. Preferably it is 0.44 or less, More preferably, it is 0.435 or less.

  The reason for limiting the content of each component constituting the glass of the present invention (indicated by cation% and anion%) will be described below. In the following description, the content “%” of the glass component of the present invention is cation% for the cation component and% anion for the anion component unless otherwise specified.

(Cation component)
P ⁵⁺ is a main component (glass-forming oxide) that forms glass, and is an essential component for enhancing the cutability in the near infrared region, but if it is less than 20%, the effect cannot be sufficiently obtained, and 50% Exceeding this is not preferable because the glass becomes unstable and the weather resistance decreases. The content of P ⁵⁺ is preferably 22 to 48%, more preferably 25 to 46%, and still more preferably 30 to 44%.

Al ³⁺ is a main component (glass-forming oxide) that forms glass, and is a component for enhancing weather resistance. However, if it is less than 5%, the effect cannot be sufficiently obtained, and if it exceeds 20%, glass Becomes unstable and the near-infrared cutting property is lowered, which is not preferable. The content of Al ³⁺ is preferably 6 to 18%, more preferably 6.5 to 15%, and still more preferably 7 to 13%.

Li ⁺ , Na ⁺ and K ⁺ preferably contain at least one of these, and are components for lowering the melting temperature, lowering the liquidus temperature of the glass, stabilizing the glass, and the like. is there. If ΣR ′ ⁺ (ΣR ′ ⁺ is the total amount of Li ⁺ , Na ⁺ , K ⁺ ) is less than 15%, the effect cannot be sufficiently obtained, and if it exceeds 35%, the glass becomes unstable. It is not preferable. The content of ΣR ′ ⁺ is preferably 18 to 33%, more preferably 19 to 31%, and still more preferably 20 to 30%.

Li ⁺ is a component for lowering the melting temperature of the glass, lowering the liquidus temperature of the glass, stabilizing the glass, and the like. When Li ⁺ is contained, if less than 0.1%, the effect is not sufficiently obtained, and if it exceeds 35%, the glass becomes unstable, which is not preferable. The content of Li ⁺ is preferably 1 to 33%, more preferably 3 to 31%, and still more preferably 5 to 30%.

Na ⁺ is a component for lowering the melting temperature of the glass, lowering the liquidus temperature of the glass, stabilizing the glass, and the like. In the case of containing Na ⁺ , if less than 0.1%, the effect cannot be sufficiently obtained, and if it exceeds 35%, the glass becomes unstable, which is not preferable. The content of Na ⁺ is preferably 1 to 33%, more preferably 3 to 31%, and still more preferably 5 to 30%.

K ⁺ is a component for lowering the melting temperature of the glass, lowering the liquidus temperature of the glass, and the like. When K ⁺ is contained, if less than 0.1%, the effect is not sufficiently obtained, and if it exceeds 35%, the glass becomes unstable, which is not preferable. The content of K ⁺ is preferably 1 to 33%, more preferably 3 to 31%, and still more preferably 5 to 30%.

Ca ²⁺ is a component for lowering the melting temperature of the glass, lowering the liquidus temperature of the glass, stabilizing the glass, increasing the strength of the glass, and the like. When Ca ²⁺ is contained, if less than 3%, the effect is not sufficiently obtained, and if it exceeds 15%, the glass becomes unstable and devitrification deteriorates, which is not preferable. The content of Ca ²⁺ is preferably 4 to 13%, more preferably 5 to 12%.

Sr ²⁺ is a component for lowering the melting temperature of the glass, lowering the liquidus temperature of the glass, stabilizing the glass, and the like. When Sr ²⁺ is contained, the effect is not sufficiently obtained if it is less than 3%, and if it exceeds 10%, the glass becomes unstable, devitrification deteriorates, and the strength of the glass is lowered. The content of Sr ²⁺ is preferably 3.5 to 9%, more preferably 4 to 8.5%.

Ba ²⁺ is an essential component for lowering the melting temperature of the glass, lowering the liquidus temperature of the glass, stabilizing the glass, and the like. When Ba ²⁺ is contained, the effect is not sufficiently obtained if it is less than 0.1%, and if it exceeds 10%, the glass becomes unstable, devitrification deteriorates, and the strength of the glass is lowered. The content of Ba ²⁺ is preferably 0.5 to 8%, more preferably 1 to 7%.

Zn ²⁺ is not an essential component, but has effects such as lowering the melting temperature of the glass, lowering the liquidus temperature of the glass, and increasing the chemical durability of the glass. In the case of containing Zn ²⁺ , if less than 1%, the effect is not sufficiently obtained, and if it exceeds 30%, the glass becomes unstable and devitrification deteriorates, and the glass solubility deteriorates. The content of Zn ²⁺ is preferably 1 to 25%, more preferably 1 to 20%.

Cu ²⁺ is an essential component for cutting near infrared rays, and the content is preferably 0.5% or more and less than 25%. When the content is less than 0.5%, the effect cannot be sufficiently obtained when the thickness of the glass is reduced, and when it is 25% or more, the visible region transmittance is lowered, which is not preferable. The Cu ²⁺ content is preferably 0.7 to 24%, more preferably 0.9 to 23%, and still more preferably 1.0 to 22%.

The glass of the present invention may contain 0 to 1% of Sb ³⁺ as an optional cation component. Sb ³⁺ is not an essential component, but has an effect of increasing the visible region transmittance. When Sb ³⁺ is contained, if it exceeds 1%, the stability of the glass is lowered, which is not preferable. The content of Sb ³⁺ is preferably 0.01 to 0.8%, more preferably 0.05 to 0.5%, and still more preferably 0.1 to 0.3%.

  The glass of the present invention can further contain other components normally contained in a fluorophosphate glass such as S, Si, B, etc., as optional cation components, as long as the effects of the present invention are not impaired. The total content of these components is preferably 5% or less.

(Anion component)
O ²⁻ is an essential component for decreasing the ultraviolet transmittance in order to stabilize the glass, increase the visible region transmittance, increase the mechanical properties such as strength, hardness, and elastic modulus. 60 to 90% is preferable. If the content of O ²⁻ is less than 60%, the effect cannot be sufficiently obtained. If the content of O ²⁻ exceeds 90%, the glass becomes unstable. The content of O ²⁻ is more preferably 65 to 88%, and still more preferably 70 to 86%.

F ⁻ is an essential component for improving the weather resistance in order to stabilize the glass, but if it is less than 10%, the effect cannot be sufficiently obtained, and if it exceeds 40%, the strength, hardness, elastic modulus, etc. This is not preferable because there is a possibility that the mechanical characteristics are lowered, the volatility is increased, and the striae is increased. The content of F ⁻ is preferably 11 to 35%, more preferably 13 to 30%.

  The glass of the present invention can further contain other components normally contained in a fluorophosphate glass such as Cl, Br, and I as an optional anion component as long as the effects of the present invention are not impaired. The total content of these components is preferably 5% or less.

  Next, the content of other components that are optional components other than the above-described components of the present invention will be described. In the present specification, “substantially not contained” means that it is not intended to be used as a raw material, and it is regarded as not containing a raw material component or an inevitable impurity mixed from a manufacturing process.

The glass of the present invention preferably contains substantially no PbO, As ₂ O ₃ , V ₂ O ₅ , YbF ₃ , or GdF ₃ . PbO is a component that lowers the viscosity of the glass and improves manufacturing workability. As ₂ O ₃ is a component that acts as an excellent clarifier that can generate a clarified gas in a wide temperature range. However, since PbO and As ₂ O ₃ are environmentally hazardous substances, it is desirable not to contain them as much as possible. Since V ₂ O ₅ has absorption in the visible region, it is desirable that V ₂ O ₅ is not contained as much as possible in the near-infrared cut filter glass for a solid-state imaging device that is required to have a high visible region transmittance. YbF ₃ and GdF ₃ are components that stabilize the glass, but since the raw materials are relatively expensive and lead to an increase in cost, it is desirable that YbF ₃ and GdF ₃ are not contained as much as possible. For these components, “substantially does not contain” means that they are not intended as raw materials, and the content of each component in the near-infrared cut filter glass is 0.1% or less, respectively. To do.

In the glass of the present invention, a nitrate compound or a sulfate compound having a cation forming glass can be added as an oxidizing agent or a clarifying agent. The oxidizing agent has an effect of improving the visible transmittance and improving the near-infrared cutability by increasing the ratio of Cu ²⁺ ions in the total amount of Cu in the glass. The addition amount of the nitrate compound or sulfate compound is preferably 0.5 to 10% by mass with the addition of the outer split to the raw material mixture. If the addition amount is less than 0.5% by mass, the effect of improving the transmittance is difficult to be obtained, and if it exceeds 10% by mass, glass formation tends to be difficult. More preferably, it is 1-8 mass%, More preferably, it is 3-6 mass%.

Examples of the nitrate compound include Al (NO ₃ ) ₃ , LiNO ₃ , NaNO ₃ , KNO ₃ , Ca (NO ₃ ) ₂ , Sr (NO ₃ ) ₂ , Ba (NO ₃ ) ₂ , Zn (NO ₃ ) ₂ , Cu (NO ₃ ) ₂ etc. The sulfate _compound is _{Al 2 (SO 4) 3 ·} 16H 2 O, Li 2 SO 4, Na 2 SO 4, K 2 SO 4, CaSO 4, SrSO 4, BaSO 4, ZnSO 4, CuSO 4 , etc. .

  The glass of the present invention preferably has a Vickers hardness of 430 Hv or higher. When the Vickers hardness is less than 430 Hv, problems such as being easily broken when thinned and easily causing scratches in the polishing process occur. Therefore, when the present glass is used in an optical apparatus, the glass may be damaged. Preferably it is 435 Hv or more.

  Moreover, it is preferable that the average transmittance | permeability of the light with a wavelength of 450-600 nm when the glass of this invention is 0.1-0.3 mm thick is 80% or more. By setting it to 80% or more, light in the visible range can be sufficiently transmitted, and a clear image can be displayed when used in an imaging apparatus.

  Moreover, when the glass of this invention is 0.1-0.3 mm thick, it is preferable that the wavelength used as the transmittance | permeability 50% is 600-650 nm. By satisfying such conditions, it is possible to realize desired optical characteristics in a sensor that is required to be thin. Furthermore, when the thickness is 0.03 to 0.3 mm, the transmittance of light having a wavelength of 450 nm is set to 80%, so that a near-infrared cut filter having more excellent optical characteristics is obtained.

The transmittance value was converted so as to be a value in the case of a wall thickness of 0.1 to 0.3 mm. The transmittance was converted using the following formula 1. T _i1 is the internal transmittance of the measurement sample (data excluding front and back reflection loss), t ₁ is the thickness (mm) of the measurement sample, T _i2 is the transmittance of the converted value, and t ₂ is , Refers to the wall thickness to be converted (in the present invention, 0.1 to 0.3 mm).

  In addition, since the near-infrared cut filter glass of this invention respond | corresponds to size reduction and thickness reduction of an imaging device or its mounting apparatus, even if the thickness of glass is thin, a favorable spectral characteristic is acquired. The thickness of the glass is preferably 1 mm or less, more preferably 0.8 mm or less, still more preferably 0.6 mm or less, and most preferably 0.4 mm or less. Further, the lower limit of the glass wall thickness is not particularly limited, but considering the strength that is difficult to break during the manufacture of the glass or when incorporated into the imaging device, it is preferably 0.03 mm or more, more preferably 0.05 mm or more. More preferably, it is 0.07 mm or more, and most preferably 0.1 mm or more.

  The glass of the present invention may be a near infrared cut filter by forming an optical multilayer film on at least one surface of the glass after being formed into a predetermined shape. Examples of the optical multilayer film include an IR cut film, a UV / IR cut film (a film that reflects ultraviolet rays and near infrared rays), a UV cut film, and an antireflection film. These optical thin films can be formed by a known method such as vapor deposition or sputtering.

An adhesion reinforcing film may be provided between the glass and the optical multilayer film. By providing the adhesion reinforcing film, the adhesion between the glass and the optical multilayer film is improved, and the film peeling can be suppressed. Examples of the adhesion reinforcing film include silicon oxide (SiO ₂ ), titanium oxide (TiO ₂ ), lanthanum titanate (La ₂ Ti ₂ O ₇ ), aluminum oxide (Al ₂ O ₃ ), aluminum oxide and zirconium oxide ( Examples thereof include a mixture with ZrO ₂ ), magnesium fluoride (MgF ₂ ), calcium fluoride (CaF ₂ ), strontium fluoride (SrF ₂ ), and fluorine silicone. A substance containing fluorine or oxygen has higher adhesion, and in particular, magnesium fluoride and / or titanium oxide is preferable as an adhesion-strengthening film because adhesion to glass or film is increased. The adhesion reinforcing film may be a single layer or two or more layers. In the case of two or more layers, a plurality of substances may be combined.

  The near-infrared cut filter glass of the present invention can be produced as follows. First, the raw materials are weighed and mixed so that the obtained glass is in the above composition range (mixing step). This raw material mixture is accommodated in a platinum crucible and heated and melted at a temperature of 700 to 950 ° C. in an electric furnace (dissolution step). After sufficiently stirring and clarifying, it is cast into a mold, cut and polished to form a flat plate having a predetermined thickness (molding process).

  In the melting step of the manufacturing method, it is preferable that the highest temperature of the glass during glass melting is 950 ° C. or lower. This is because when the highest temperature of the glass during glass melting exceeds the above temperature, the transmittance characteristics deteriorate, and the volatilization of fluorine is promoted to make the glass unstable. The above temperature is more preferably 930 ° C. or lower, further preferably 900 ° C. or lower, and still more preferably 880 ° C. or lower.

  In addition, if the temperature in the melting step is too low, problems such as devitrification occur during melting, and it takes time to melt off, so that the temperature is preferably 700 ° C. or higher, more preferably 750 ° C. or higher.

  Tables 1 and 2 show examples of the present invention and comparative examples. Examples 1 to 5 and Examples 9 to 14 are examples of the present invention, and Examples 6 to 8 are comparative examples of the present invention.

[Production of glass]
These glasses are weighed and mixed so that the glass components after melt molding have the compositions shown in Tables 1 and 2 (cation%, anion%), and placed in a platinum crucible having an internal volume of about 1 L. After melting, clarifying and stirring for 2 hours at a temperature of 950 ° C., cast into a rectangular mold with a length of 50 mm × width 50 mm × height 20 mm preheated to approximately 50 to 500 ° C., and then slowly cool at about 1 ° C./min. It was. Next, the front and back surfaces were optically polished to obtain glass having the thicknesses shown in Tables 1 and 2.

In addition, the raw material of each glass is one selected from H ₃ PO ₄ and Al (PO ₃ ) _{3 in} the case of P ⁵⁺ , and AlF ₃ , Al (PO ₃ ) ₃ and Al ₂ O _{3 in} the case of Al ^3+. Selected from LiF, LiNO ₃ , Li ₂ CO ₃ and LiPO _{3 in} the case of Li ⁺ , and selected from SrF ₂ , SrCO ₃ and Sr (PO ₃ ) _{2 in} the case of Sr ^2+. In the case of Ba ²⁺ , one selected from BaF ₂ , BaCO ₃ and Ba (PO ₃ ) ₂ , and Na ⁺ is one selected from NaCl, NaBr, NaI, NaF and Na (PO ₃ ) In the case of K ⁺ and Ca ²⁺ , one kind selected from fluoride, carbonate and metaphosphate was used, and in the case of Cu ²⁺ and Cu ⁺ , CuO was used.

[Evaluation]
The transmittance of light having a wavelength of 450 to 600 nm was measured with a spectrophotometer (manufactured by Hitachi, U-4100). Table 1 shows the average transmittance of light having a wavelength of 450 to 600 nm and the transmittance of light having a wavelength of 450 nm. The wavelength at which the transmittance was 50% was calculated as 645 nm.

  Devitrification was evaluated by the following procedure. First, the glass was melted at 900 ° C. for 2 hours, and then the melting temperature was lowered to 800 ° C. for 1 hour. Thereafter, the molded glass block was visually confirmed, and those in which foreign matters were seen were indicated as x, and those in which foreign matters were not observed were indicated as ◯.

  Vickers hardness was evaluated by the following procedure. As a measuring apparatus, a Vickers hardness tester (Futuretec Corporation, FLC-ARS9000F) was used. A 100 gf indenter was placed in the glass, and Hv was calculated from the length of the indentation. The average value of the results of 15 points measured is shown in Table 1.

  Further, for Examples 1, 2, 5 and 8, a graph of the transmittance in which the wavelength at which the transmittance is 50% is converted to 645 nm is shown in FIG.

In Examples of the present invention, in Examples 1, 2, and 5, it was difficult to devitrify and high strength glass was obtained. Further, in Examples 11 and 12, melting was possible at a lower temperature (800 ° C.), thereby obtaining a glass having a very high transmittance at a wavelength of 400 nm and an average transmittance at a wavelength of 400 to 600 nm. In addition, about Example 6 used as a comparative example, devitrification occurred because it did not contain Ba ²⁺ . In Example 7, since the value of Ba ²⁺ / ΣR ²⁺ was large, the glass had low Vickers hardness. About Example 8, although strength was high by containing Mg, devitrification occurred. As a result, Example 8 could not be melted at a low temperature (850 to 860 ° C.) like Examples 1, 2, and 5, and the transmittance was lower than that of Examples 1, 2, and 5 at 450 nm.

  According to the present invention, even when the content of the Cu component is large due to thinning, the glass composition is difficult to devitrify, and because it can be melted at a low temperature, the transmittance of light in the visible region is increased, so that the size is reduced. -Extremely useful for near-infrared cut filter applications of thinned imaging devices.

Claims (11)

P, F, O, Cu are contained as essential components, Mg is not substantially contained, and the content of Ba ²⁺ in cation% / ΣR ²⁺ (ΣR ²⁺ is the total amount of Ba ²⁺ , Sr ²⁺ , Ca ^2+. The near-infrared cut filter glass is characterized by being 0.05 to 0.2. The near infrared ray according to claim 1, wherein the content of Ca ²⁺ in cation% / ΣR ²⁺ is 0.35 to 0.7, and the content of Sr ²⁺ / ΣR ²⁺ is 0.2 to 0.45. Cut filter glass. P ⁵⁺ 20-50% in ^{terms of} cation%,
Al ³⁺ 5-20%,
ΣR ′ ⁺ (ΣR ′ ⁺ is the total amount of Li ⁺ , Na ⁺ , K ⁺ ) 15-35%,
Ca ²⁺ 3-15%,
Sr ²⁺ 3-10%,
Ba ²⁺ 0.1-10%,
Cu ²⁺ 0.5-25%,
F ^- 10 to 40% in anion%,
O ^2- 60~90%,
The near-infrared cut filter glass of Claim 1 or 2 characterized by the above-mentioned. The near-infrared cut filter glass according to any one of claims 1 to 3, wherein Li ⁺ is contained in an amount of 0.1 to 35% in terms of cation. The near-infrared cut filter glass according to any one of claims 1 to 3, comprising Na ⁺ 0.1 to 35% in terms of cation%. The near-infrared cut filter glass according to any one of claims 1 to 3, which contains K ⁺ 0.1 to 35% in terms of cation%. The near-infrared cut filter glass according to any one of claims 1 to 6, comprising Zn ²⁺ 1 to 25% in terms of cation%.   It has the near-infrared cut filter glass of any one of Claims 1-6, and the optical multilayer film provided in the at least 1 surface of this near-infrared cut filter glass, The said near-infrared cut filter glass, A near-infrared cut filter comprising an adhesion reinforcing film between optical multilayer films.   The near-infrared cut filter according to claim 8, wherein the adhesion reinforcing film contains fluorine and / or oxygen.   The near-infrared cut filter according to claim 9, wherein the adhesion reinforcing film contains magnesium fluoride and / or titanium oxide.   The near-infrared ray according to any one of claims 8 to 10, wherein the optical multilayer film is selected from an IR cut film, a UV / IR cut film, a UV cut film, an antireflection film, and a combination thereof. Cut filter.

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