Optical filter

Abstract

The present invention relates to an optical filter provided with glass, a barrier film (1) provided between the glass and a dielectric multilayer film (1), a barrier film (2) provided between the glass and a dielectric multilayer film (2), and a light absorption layer provided on the dielectric multilayer film (2), in which the glass is phosphate glass or fluorophosphate glass. The light absorbing layer contains a near-infrared ray absorbing dye, and the optical filter satisfies specific spectral characteristics (i-1)-(i-3) and (i-6).

Description

TECHNICAL FIELD

[0001] The present application relates to an optical filter that allows transmission of visible light and shields near-infrared light. BACKGROUND

[0002] In an imaging device using a solid-state imaging element, in order to reproduce a color tone well and obtain a clear image, an optical filter that allows transmission of light in a visible light wavelength region (hereinafter also referred to as "visible light") and shields light in a near-infrared light wavelength region (hereinafter also referred to as "near-infrared light") is used.

[0003] As such an optical filter, for example, a reflection type optical filter in which medium thin films (medium multilayer film) of different refractive indexes are alternately stacked on one side or both sides of a transparent substrate to reflect light to be shielded by interference of light, an absorption type optical filter in which glass or a pigment that absorbs light in a specific wavelength region is used to absorb light to be shielded, an optical filter that combines a reflection type and an absorption type, and the like can be cited.

[0004] Here, as glass that absorbs light, phosphate glass and fluorophosphate glass are known, but are easily affected by moisture and the like in the environment. In particular, phosphate glass has a possibility that phosphate is eluted to decompose other constituent materials of the optical filter. Therefore, a technique for preventing elution of phosphate has been studied.

[0005] In Patent Literature 1, phosphate glass in which a protective film is formed by coating a surface with alumina in order to improve moisture resistance is described.

[0006] In Patent Literature 2, an infrared cut filter obtained by joining an infrared absorbing glass such as phosphate glass and a protective glass with an adhesive in order to improve moisture resistance is described.

[0007] PRIOR ART DOCUMENTS

[0008] PATENT LITERATURE

[0009] Patent Literature 1: Japanese Patent Application Laid-Open No. 4-139035

[0010] Patent Literature 2: Japanese Patent Application Laid-Open No. 2016-18092 SUMMARY

[0011] PROBLEMS TO BE SOLVED BY THE INVENTION

[0012] However, in the technique described in Patent Literature 1, although the surface of the phosphate glass covered with the alumina protective film is less likely to be affected by moisture, the moisture resistance is improved, but the reaction of the glass end surface not covered with the protective film with moisture cannot be suppressed, and in addition, phosphate eluted from the glass end surface reacts with the alumina protective film, which can cause peeling of the film due to a decrease in adhesion.

[0013] In addition, in the technology described in Patent Literature 2, since the adhesive is an organic material, moisture easily enters from the vicinity of the end surface. Therefore, there is a possibility that the adhesive is deteriorated by phosphoric acid eluted from the glass, and thus the adhesion is reduced.

[0014] In addition, the filter having the dielectric multilayer film has a problem in that the optical film thickness of the dielectric multilayer film changes depending on the incident angle of light, and thus the change in the spectral transmittance curve caused by the incident angle becomes a problem. In particular, with the recent low-height of the camera module, use under high incident angle conditions is assumed, and thus a filter which is less affected by the incident angle is required.

[0015] An object of the present application is to provide a filter which is excellent in moisture resistance, and which is excellent in transmittance in the visible light region and shielding property in the near-infrared light region even at high incident angles.

[0016] Means for solving the problem

[0017] The present application provides a filter and the like having the following configuration.

[0018] A filter including: a glass; a dielectric multilayer film 1 and a dielectric multilayer film 2 provided on both sides of the glass; a barrier film 1 provided between the glass and the dielectric multilayer film 1; a barrier film 2 provided between the glass and the dielectric multilayer film 2; and a light absorbing layer provided on the dielectric multilayer film 2, wherein the glass is a phosphate glass having near-infrared light absorption property and substantially containing no fluorine atom, or a fluorophosphate glass having near-infrared light absorption property and containing a fluorine atom, the light absorbing layer contains a near-infrared light absorbing pigment having a maximum absorption wavelength in the range of 680 nm to 800 nm, in a case where the glass is the phosphate glass, the barrier film 1 and the barrier film 2 each independently contain one or more selected from TiO2, Nb2O5, Ta2O5, and HfO2, in a case where the glass is the fluorophosphate glass, the barrier film 1 and the barrier film 2 each independently contain one or more selected from TiO2, Al2O3, Nb2O5, Ta2O5, and HfO2, the filter satisfies the following spectral properties (i-1) to (i-3) and (i-6).

[0019] (i-1) The average transmittance at a wavelength of 440 nm to 500 nm is 80% or more at an incident angle of 0 degrees, and the average transmittance at a wavelength of 440 nm to 500 nm is 70% or more at an incident angle of 60 degrees.

[0020] (i-2) The average transmittance of wavelengths from 750 nm to 1000 nm at an incident angle of 0 degrees is 1% or less, and the average transmittance of wavelengths from 750 nm to 1000 nm at an incident angle of 60 degrees is 1% or less.

[0021] (i-3) In a spectral transmittance curve at an incident angle of 0 degrees, a wavelength IR10 at which the transmittance is 10% (0deg) in a range from 600 nm to 700 nm.

[0022] (i-6) When the medium multilayer film 1 side is taken as an incident direction, the maximum reflectance of wavelengths from 850 nm to 1200 nm at an incident angle of 5 degrees is 85% or more.

[0023] Effects of the Invention

[0024] According to the present application, an optical filter which is excellent in moisture resistance and in which the transmittance in the visible light region and the shielding property in the near infrared light region are excellent even at a high incident angle can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a cross-sectional view schematically showing one example of an optical filter of one embodiment.

[0026] Figure 2 is a cross-sectional view schematically showing another example of an optical filter of one embodiment.

[0027] Figure 3 is a graph showing spectral transmittance curves of glasses 1, 3, and 4.

[0028] Figure 4 is a graph showing a spectral transmittance curve of glass 2.

[0029] Figure 5 is a graph showing spectral transmittance curves of light absorbing layers 1 and 2.

[0030] Figure 6 is a graph showing spectral transmittance and reflectance curves of the optical filter of Example 2-1.

[0031] Figure 7 is a graph showing spectral transmittance and reflectance curves of the optical filter of Example 2-3. DETAILED DESCRIPTION

[0032] Hereinafter, an embodiment of the present application will be described.

[0033] In this specification, a near infrared absorbing dye is sometimes simply referred to as "NIR dye", and an ultraviolet absorbing dye is sometimes simply referred to as "UV dye".

[0034] In the present specification, a compound represented by formula (I) is referred to as compound (I). The same applies to compounds represented by other formulas. A pigment containing compound (I) is also referred to as pigment (I), and the same applies to other pigments. In addition, a group represented by formula (I) is also referred to as group (I), and the same applies to groups represented by other formulas.

[0035] In the present specification, the transmittance of glass, the transmittance of a light absorbing layer in the case where a pigment is contained in a resin, the transmittance determined by dissolving a pigment in a solvent such as dichloromethane, the transmittance of a dielectric multilayer film, and the transmittance spectrum of a light filter having a dielectric multilayer film are all "external (measured) transmittance" including the loss of reflection of the front and back surfaces in the case where they are described as "transmittance".

[0036] In the present specification, the transmittance of a specific wavelength range, for example, 90% or more means that the transmittance is not less than 90% in the entire wavelength range, that is, the minimum transmittance is 90% or more in the wavelength range. Similarly, the transmittance of a specific wavelength range, for example, 1% or less means that the transmittance is not more than 1% in the entire wavelength range, that is, the maximum transmittance is 1% or less in the wavelength range. The average transmittance in a specific wavelength range is the arithmetic average of the transmittance per 1 nm in the wavelength range.

[0037] The spectral characteristics can be measured using a UV-visible spectrophotometer.

[0038] In the present specification, "~" indicating a numerical range includes the upper limit and the lower limit.

[0039] <Light filter>

[0040] A light filter (hereinafter, also referred to as "the present light filter") of one embodiment of the present application includes: a glass that is a phosphate glass or a fluorophosphate glass; a dielectric multilayer film 1 and a dielectric multilayer film 2 provided on both sides of the glass; and a light absorbing layer provided on the dielectric multilayer film 2. The present light filter has a barrier film 1 between the glass and the dielectric multilayer film 1 and a barrier film 2 between the glass and the dielectric multilayer film 2. As described later, the barrier films 1 and 2 contain a specific material. The barrier films prevent the glass from reacting with moisture in the environment, and a light filter with excellent moisture resistance is obtained.

[0041] The structure of the present light filter is described with reference to drawings. Figures 1-2 A cross-sectional view schematically illustrates an example of a light filter of one embodiment.

[0042] Figure 1The filter 1A shown is an example having the glass 10, the dielectric multilayer film 21 provided on one main surface side of the glass 10, the dielectric multilayer film 22 provided on the other main surface side of the glass 10, the light absorbing layer 30 provided on the dielectric multilayer film 22, the barrier film 11 provided between the glass 10 and the dielectric multilayer film 21, and the barrier film 12 provided between the glass 10 and the dielectric multilayer film 22.

[0043] Figure 2 The filter 1B shown is an example further having the dielectric multilayer film 23 laminated on the surface of the light absorbing layer 30.

[0044] The filter of the embodiment of the present application satisfies all of the following spectral characteristics (i-1) to (i-3), (i-6).

[0045] (i-1) The average transmittance of wavelengths of 440 nm to 500 nm is 80% or more at an incident angle of 0 degrees, and the average transmittance of wavelengths of 440 nm to 500 nm is 70% or more at an incident angle of 60 degrees.

[0046] (i-2) The average transmittance of wavelengths of 750 nm to 1000 nm is 1% or less at an incident angle of 0 degrees, and the average transmittance of wavelengths of 750 nm to 1000 nm is 1% or less at an incident angle of 60 degrees.

[0047] (i-3) In the spectral transmittance curve at an incident angle of 0 degrees, the wavelength IR10 at which the transmittance is 10% (0deg) in the range of 600 nm to 700 nm.

[0048] (i-6) When the dielectric multilayer film 1 side is taken as the incident direction, the maximum reflectance of wavelengths of 850 nm to 1200 nm is 85% or more at an incident angle of 5 degrees.

[0049] The filter of the present application satisfying all of the spectral characteristics (i-1) to (i-3), (i-6) is a filter in which the transmittance of visible light as indicated by the characteristic (i-1) is excellent, and the shielding property of near-infrared light of wavelengths of 750 nm to 1000 nm as indicated by the characteristic (i-2) is excellent.

[0050] In addition, the filter of the embodiment of the present application preferably satisfies the following spectral characteristics (i-4) and (i-5).

[0051] (i-4) In the spectral transmittance curve at an incident angle of 0 degrees, the wavelength IR10 at which the transmittance is 10% (0deg) at which the transmittance is 10% in the range of 600 nm to 700 nm in the spectral transmittance curve at an incident angle of 60 degrees. (60deg)The absolute value of the difference is 20 nm or less.

[0052] (i-5) The transmittance at a wavelength of 1100 nm at an incident angle of 0 degrees is 1% or less, and the transmittance at a wavelength of 1100 nm at an incident angle of 60 degrees is 3% or less.

[0053] The optical filter satisfying the spectral characteristics (i-4) and (i-5) is an optical filter in which the shielding property of near-infrared light at a wavelength of 1100 nm as indicated by the characteristic (i-5) is excellent, and the transmittance is not easily shifted even at a high incident angle as indicated by the characteristic (i-4).

[0054] Satisfying the spectral characteristic (i-1) means that the transmittance in the visible light region of 440 nm to 500 nm is excellent even at a high incident angle.

[0055] The average transmittance at a wavelength of 440 nm to 500 nm at an incident angle of 0 degrees is preferably 81% or more, more preferably 82% or more, and the average transmittance at a wavelength of 440 nm to 500 nm at an incident angle of 60 degrees is preferably 71% or more, more preferably 72% or more.

[0056] Further, in order to satisfy the spectral characteristic (i-1), for example, a medium multilayer film, glass, a near-infrared light absorbing pigment having excellent transmittance in the visible light region can be exemplified.

[0057] Satisfying the spectral characteristic (i-2) means that the shielding property in the near-infrared light region of 750 nm to 1000 nm is excellent even at a high incident angle.

[0058] The average transmittance at a wavelength of 750 nm to 1000 nm at an incident angle of 0 degrees is preferably 0.5% or less, more preferably 0.2% or less, and the average transmittance at a wavelength of 750 nm to 1000 nm at an incident angle of 60 degrees is preferably 0.5% or less, more preferably 0.2% or less.

[0059] Further, in order to satisfy the spectral characteristic (i-2), for example, shielding light by using glass, the absorption capacity of a near-infrared light absorbing pigment can be exemplified.

[0060] Satisfying the spectral characteristic (i-3) means that the wavelength range of 600 nm to 700 nm is a region in which the spectral transmittance curve rises from the near-infrared shielding region to the visible light transmittance region.

[0061] Wavelength IR10 (0deg) It is preferable in the range of 620 nm to 700 nm, more preferably in the range of 650 nm to 700 nm.

[0062] Satisfying the spectral characteristic (i-4) means that the spectral transmittance curve is not easily shifted in the wavelength range of 600 nm to 700 nm even for a high incident angle.

[0063] Wavelength IR10 (0deg) Wavelength IR10 (60deg) The absolute value of the difference is preferably 15 nm or less, and more preferably 13 nm or less.

[0064] Further, in order to satisfy the spectral characteristic (i-4), for example, it is possible to cite: shielding light in the wavelength range of 600 nm to 700 nm by the absorption ability of a glass that is not affected by the incident angle, a near-infrared light absorbing pigment.

[0065] Satisfying the spectral characteristic (i-5) means that the shielding property in the near-infrared light region of 1100 nm is excellent even for a high incident angle.

[0066] The transmittance at a wavelength of 1100 nm at an incident angle of 0 degree is preferably 0.5% or less, and more preferably 0.2% or less, and the transmittance at a wavelength of 1100 nm at an incident angle of 60 degrees is preferably 2% or less, and more preferably 1% or less.

[0067] Further, in order to satisfy the spectral characteristic (i-5), for example, it is possible to cite: shielding light by the absorption ability of a glass.

[0068] Satisfying the spectral characteristic (i-6) means that the light shielding property in the range of 850 nm to 1200 nm is ensured by the reflection characteristic of the dielectric multilayer film 1.

[0069] The maximum reflectance at a wavelength of 850 nm to 1200 nm is preferably 90% or more, and more preferably 95% or more.

[0070] The optical filter of the present embodiment preferably satisfies the following spectral characteristic (i-7) and spectral characteristic (i-8).

[0071] (i-7) The maximum reflectance at a wavelength of 450 nm to 750 nm at an incident angle of 60 degrees when the light absorbing layer side is taken as the incident direction is 20% or less.

[0072] (i-8) The maximum reflectance at a wavelength of 750 nm to 1200 nm at an incident angle of 60 degrees when the light absorbing layer side is taken as the incident direction is 42% or less.

[0073] Satisfying the spectral property (i-7), the spectral property (i-8) means that the reflection property of the dielectric multilayer film 2 is low in the region from visible light to near-infrared light at wavelengths of 450 nm to 1200 nm even at a high angle of incidence. Even if the reflection property of the near-infrared light of the multilayer film 2 is low, absorption is performed using the glass, a near-infrared light-absorbing dye, and in addition, reflection is performed using the multilayer film 1, and thus the light shielding property of the filter as a whole can be sufficiently ensured.

[0074] The maximum reflectance at wavelengths of 450 nm to 750 nm is more preferably 19.8% or less, and further preferably 19.5% or less.

[0075] The maximum reflectance at wavelengths of 750 nm to 1200 nm is more preferably 41.5% or less, and further preferably 41.0% or less.

[0076] The spectral property (i-7) and the spectral property (i-8) can be achieved, for example, by using the dielectric multilayer film 2 and the barrier film 2 in which X is in a specific range as described later.

[0077] The filter of the present embodiment preferably satisfies the following spectral property (i-9).

[0078] (i-9) When the light-absorbing layer side is taken as the direction of incidence, the maximum reflectance at wavelengths of 450 nm to 750 nm is 7.5% or less at an angle of incidence of 5 degrees.

[0079] Satisfying the spectral property (i-9) means that the reflection property of the dielectric multilayer film 2 is low in the region from visible light to near-infrared light at wavelengths of 450 nm to 750 nm.

[0080] The maximum reflectance at wavelengths of 450 nm to 750 nm is more preferably 7.4% or less, and further preferably 7.3% or less.

[0081] The spectral property (i-9) can be achieved, for example, by using the dielectric multilayer film 2 and the barrier film 2 in which X is in a specific range as described later.

[0082] The filter of the present embodiment preferably satisfies the following spectral property (i-10).

[0083] (i-10) When the dielectric multilayer film 1 side is taken as the direction of incidence, the average reflectance at wavelengths of 800 nm to 1100 nm is 95% or more at an angle of incidence of 5 degrees.

[0084] Satisfying the spectral property (i-10) means that the dielectric multilayer film 1 has a wide reflection property in the near-infrared light region at wavelengths of 800 nm to 1100 nm.

[0085] The average reflectance of the wavelength of 800 nm to 1100 nm is more preferably 96% or more, and further preferably 97% or more.

[0086] <GLASS>

[0087] The optical filter of the present embodiment is provided with a phosphate glass or a fluorophosphate glass. The phosphate glass or the fluorophosphate glass has near-infrared ray absorbability and also functions as a support of the optical filter. In addition, since light is shielded by the absorbance characteristics, the light shielding property is not easily affected by the incident angle, unlike the dielectric multilayer film.

[0088] As the glass, it is preferable that the transmittance at a wavelength of 420 nm be 80% or more, the transmittance at a wavelength of 800 nm be 6% or less, and the transmittance at a wavelength of 1200 nm be 25% or less, in terms of a plate thickness of 0.2 mm. If the glass satisfies the spectral characteristics, the transmittance of visible light is sufficient and the near-infrared light absorbance is also excellent, and thus is preferable.

[0089] In the present specification, the phosphate glass refers to a glass containing 40% or more of P2O5 in terms of mol% on an oxide basis and substantially not containing a fluorine atom. Here, substantially not containing a fluorine atom means that the content of F is less than 3% in terms of an addition ratio when the content of F contained in the glass is expressed in terms of an addition ratio, with the content of the component elements other than F contained in the glass being set to 100% in terms of mass.

[0090] In addition, in the present specification, the fluorophosphate glass refers to a glass containing 20% or more of P2O5 in terms of mass and 3% or more of F in terms of an addition ratio. 5+ -

[0091] The phosphate glass preferably substantially does not contain a fluorine atom and contains, in terms of mol% on an oxide basis: 40% to 75% of P2O5, 10% to 30% of Al2O3, 0.1% to 30% of ΣR2O (where R2O is one or more components selected from Li2O, Na2O, K2O, Rb2O, and Cs2O, and ΣR2O represents the total content of R2O), 0% to 30% of ΣR'O (where R'O is one or more components selected from CaO, MgO, BaO, SrO, and ZnO, and ΣR'O represents the total content of R'O), 2% to 30% of CuO.

[0092] The fluorophosphate glass preferably contains, in terms of mass:

[0093] 20% to 70% of P 5+ ,​​ 1 to 20% of Al 3+ 、 0 to 30% of Li + 、 0 to 40% of Na + 、 0 to 40% of K + 、 0 to 20% of Rb + 、 0 to 20% of Cs + 、 0 to 20% of Mg 2+ 、 0 to 20% of Ca 2+ 、 0 to 30% of Sr 2+ 、 0 to 45% of Ba 2+ 、 1 to 55% of ΣR + (R + is one or more components selected from Li + , Na + , K + , Rb + , and Cs + ), 1 to 50% of ΣR' 2+ (R' 2+ is one or more components selected from Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ ), 1 to 20% of Cu 2+ , and 0 to 20% of Zn 2+ , and when the components other than F - in the glass are taken as 100% by mass, 3 to 60% by mass of F - is contained as an additive.

[0094] The components that can constitute the phosphate glass and the suitable contents thereof will be described below. In the following description of the phosphate glass, the content of each component and the total content are in mol% on an oxide basis, unless otherwise specified.

[0095] P2O5 is a main component for forming glass, and is a component for improving near-infrared cut-off. If the content of P2O5 is 40% or more, its effect can be sufficiently obtained, and if the content of P2O5 is 75% or less, problems such as instability of glass, decrease in weather resistance, and the like are not likely to occur. Therefore, the content of P2O5 is preferably 45 to 75%, more preferably 50 to 70%, further preferably 52 to 65%, still further preferably 54 to 65%, and most preferably 55 to 60%.

[0096] Al2O3 is a main component for forming glass, and is a component for improving strength of glass, improving weather resistance of glass, and the like. If the content of Al2O3 is 10% or more, its effect can be sufficiently obtained, and if the content of Al2O3 is 30% or less, problems such as instability of glass, decrease in near-infrared cut-off, and the like are not likely to occur. Therefore, the content of Al2O3 is preferably 10 to 30%, more preferably 11 to 27%, further preferably 12 to 26%, still further preferably 12.5 to 25%, and most preferably 13 to 24%. If the content of Al2O3 is 13% or more, weather resistance of glass can be particularly improved.

[0097] R2O (wherein R2O is one or more components selected from the group consisting of Li2O, Na2O, K2O, Rb2O, and Cs2O) is a component for lowering melting temperature of glass, lowering liquidus temperature of glass, stabilizing glass, and the like. If the total amount of R2O (ΣR2O) is 0.1% or more, its effect can be sufficiently obtained, and if the total amount of R2O (ΣR2O) is 30% or less, glass is not likely to become unstable, and thus is preferred. Therefore, the total amount of R2O (ΣR2O) is preferably 1 to 25%, more preferably 2 to 20%, further preferably 3 to 18%, still further preferably 4 to 17%, and most preferably 5 to 18%.

[0098] Li2O is a component for lowering melting temperature of glass, lowering liquidus temperature of glass, stabilizing glass, and the like. The content of Li2O is preferably 0 to 20%. If the content of Li2O is 20% or less, problems such as instability of glass, decrease in near-infrared cut-off, and the like are not likely to occur, and thus is preferred. The content of Li2O is more preferably 0 to 15%, further preferably 0 to 10%, still further preferably 0 to 5%, and most preferably substantially contains no Li2O.

[0099] Note that, in the present application, substantially containing no specific component means not intentionally added, and does not exclude the possibility of being mixed from raw materials or the like, and the like, to the extent that does not affect the desired characteristics.

[0100] Na2O is a component for lowering the melting temperature of the glass, lowering the liquidus temperature of the glass, stabilizing the glass, and the like. The content of Na2O is preferably 0 to 25%. If the content of Na2O is 25% or less, the glass is not easily made unstable, and thus is preferred. The content of Na2O is more preferably 0.5 to 20%, further preferably 1 to 15%, and still further preferably 2 to 10%.

[0101] K2O is a component having an effect of lowering the melting temperature of the glass, lowering the liquidus temperature of the glass, and the like. The content of K2O is preferably 0 to 25%. If the content of K2O is 25% or less, the glass is not easily made unstable, and thus is preferred. The content of K2O is more preferably 0.5 to 20%, further preferably 1 to 15%, and still further preferably 2 to 13%.

[0102] Rb2O is a component having an effect of lowering the melting temperature of the glass, lowering the liquidus temperature of the glass, and the like. The content of Rb2O is preferably 0 to 25%. If the content of Rb2O is 25% or less, the glass is not easily made unstable, and thus is preferred. The content of Rb2O is more preferably 0.5 to 20%, further preferably 1 to 15%, and still further preferably 2 to 10%.

[0103] Cs2O is a component having an effect of lowering the melting temperature of the glass, lowering the liquidus temperature of the glass, and the like. The content of Cs2O is preferably 0 to 25%. If the content of Cs2O is 25% or less, the glass is not easily made unstable, and thus is preferred. The content of Cs2O is more preferably 0.5 to 20%, further preferably 1 to 15%, and still further preferably 2 to 10%.

[0104] In addition, the alkali metal components represented by R2O described above produce a mixed alkali effect in the glass by simultaneously adding two or more kinds of components, and R + The mobility of the H+ ion decreases. Thus, when the glass is in contact with water, the H+ + ion in the glass and the H +The hydration reaction that occurs by ion exchange of the ions, the weather resistance of the glass is improved. Therefore, the glass of the present embodiment preferably contains two or more components selected from the group consisting of Li20, Na20, K20, Rb20, and Cs20. In this case, the total amount of R20 (where R20 is two or more components selected from the group consisting of Li20, Na20, K20, Rb20, and Cs20) is preferably 6% to 18% (where 7% is not included). If the total amount of R20 is 6% or more, the effect thereof can be sufficiently obtained, and if the total amount of R20 is 18% or less, problems such as the glass becoming unstable, the near-infrared cut property decreasing, the strength of the glass decreasing, and the like do not easily occur, and thus is preferred. Therefore, ΣR20 is preferably 7% to 18%, more preferably 8% to 18%, further preferably 9% to 18%, more further preferably 10% to 18%, and most preferably 10.5% to 18%.

[0105] R'O (where R'0 is one or more components selected from the group consisting of CaO, MgO, BaO, SrO, and ZnO) is a component for reducing the melting temperature of the glass, reducing the liquidus temperature of the glass, stabilizing the glass, improving the strength of the glass, and the like. The total amount of R'0 (ΣR'0) is preferably 0% to 30%. If the total amount of R'0 is 30% or less, problems such as the glass becoming unstable, the near-infrared cut property decreasing, the transmittance of short-wavelength infrared light decreasing, the strength of the glass decreasing, and the like do not easily occur, and thus is preferred. The total amount of R'0 is more preferably 0% to 25%, further preferably 0% to 20%. More further preferably 0% to 15%, more further preferably 0% to 10%.

[0106] In the phosphate glass of the present embodiment, it is preferred that substantially no divalent cations other than Cu be contained. The reason for this is as described below.

[0107] In the case where the phosphate glass of the present embodiment contains CuO, by Cu 2+ absorbing light in the near-infrared region due to the light absorption of the ions. This light absorption occurs due to the electron transition between the d orbitals of Cu 2- split by the electric field of the O 2+ of the Cu 2+ ions. When the symmetry of the O 2- ions existing around the Cu 2- ions is reduced, the splitting of the d orbitals is promoted. For example, if a cation exists around the O 2- ions are attracted by the electric field of the cation, the O 2-The symmetry of the ions decreases. As a result, d-orbital splitting is promoted, and light absorption occurs through electronic transitions between the split d-orbitals. Therefore, the light absorption in the near-infrared region is weakened, while the light absorption in the short-wavelength infrared region is enhanced. When the valence of the ion is high, the electric field strength of the cation increases. Therefore, especially when oxides containing divalent cations other than Cu are added to the glass, the near-infrared cutoff may decrease, and the transmittance of short-wavelength infrared rays may decrease.

[0108] CaO is a component used to lower the melting temperature of glass, lower the liquidus temperature of glass, stabilize glass, and improve the strength of glass. The preferred CaO content is 0% to 20%. If the CaO content is below 20%, problems such as glass instability, reduced near-infrared cutoff, and reduced short-wavelength infrared transmittance are less likely to occur, and this is therefore preferred. The CaO content is more preferably 0% to 15%, further preferably 0% to 10%, and even more preferably 0% to 5%. Most preferably, it contains virtually no CaO.

[0109] MgO is a component used to lower the melting temperature of glass, lower the liquidus temperature of glass, stabilize glass, and improve the strength of glass. The preferred MgO content is 0% to 20%. If the MgO content is below 20%, problems such as glass instability, reduced near-infrared cutoff, and reduced short-wavelength infrared transmittance are less likely to occur, and this is therefore preferred. The MgO content is more preferably 0% to 15%, further preferably 0% to 10%, and even more preferably 0% to 5%. Most preferably, it contains virtually no MgO.

[0110] BaO is a component used to lower the melting temperature of glass, lower the liquidus temperature of glass, and stabilize glass. The preferred BaO content is 0% to 20%. If the BaO content is below 20%, problems such as glass instability, reduced near-infrared cutoff, and reduced short-wavelength infrared transmittance are less likely to occur, making this preferable. A more preferred BaO content is 0% to 15%, further preferably 0% to 10%, and even more preferably 0% to 5%. The BaO content can be 0.1% or more. Most preferably, it contains virtually no BaO.

[0111] SrO is a component used to lower the melting temperature of glass, lower the liquidus temperature of glass, and stabilize glass. The preferred SrO content is 0% to 20%. If the SrO content is below 20%, problems such as glass instability, reduced near-infrared cutoff, and reduced short-wavelength infrared transmittance are less likely to occur, and this is therefore preferred. The SrO content is more preferably 0% to 15%, and even more preferably 0% to 10%. Most preferably, it contains virtually no SrO.

[0112] ZnO has an effect of lowering the melting temperature of the glass, lowering the liquidus temperature of the glass, and the like. The content of ZnO is preferably 0 to 20%. If the content of ZnO is 20% or less, problems such as deterioration of the melting property of the glass, reduction of the near-infrared cutoff property, reduction of the transmittance of the short-wavelength infrared, and the like are less likely to occur, and thus it is preferable. The content of ZnO is more preferably 0 to 15%, further preferably 0 to 10%, and still further preferably 0 to 5%. It is most preferable that the glass substantially does not contain ZnO.

[0113] CuO is a component for cutting off near-infrared rays. The content of CuO is preferably 2 to 30%. If the content of CuO is 2% or more, the effect thereof can be sufficiently obtained, and if the content of CuO is 30% or less, problems such as reduction of the transmittance in the visible region, reduction of the transmittance in the short-wavelength infrared region, and the like are less likely to occur, and thus it is preferable. The content of CuO is more preferably 5 to 25%, further preferably 8 to 20%, and still further preferably 11 to 18%. In addition, it is still further preferable that the content of CuO is 12% or more. In particular, in the case where the glass substantially does not contain divalent cations other than Cu, by making the content of CuO 12% or more, the cutoff property of near-infrared rays and the transmittance of short-wavelength infrared rays can be further improved. The content of CuO is most preferably 13 to 18%.

[0114] In order to stabilize the glass, B2O3 can be contained in a range of 15% or less. If the content of B2O3 is 15% or less, problems such as deterioration of the weather resistance of the glass, reduction of the near-infrared cutoff property, reduction of the transmittance of the short-wavelength infrared, and the like are less likely to occur, and thus it is preferable. The content of B2O3 is preferably 13% or less, more preferably 11% or less, further preferably 9% or less, still further preferably 7% or less, and most preferably the glass substantially does not contain B2O3.

[0115] MoO3 is a component for improving the transmittance of light in the visible region of the glass. If the content of MoO3 is 0.1% or more, the effect of improving the transmittance of light in the visible region of the glass can be sufficiently obtained, and if the content of MoO3 is 5% or less, problems such as reduction of the near-infrared cutoff property, generation of devitrification foreign matter in the glass, and the like are less likely to occur, and thus it is preferable. The content of MoO3 is more preferably 0.1 to 4.5%, further preferably 0.1 to 4%, still further preferably 0.1 to 3.5%, and most preferably 0.1 to 3%.

[0116] In the phosphate glass of the present embodiment, F (fluorine atom) is a component effective for improving weather resistance, but since it is an environmental load material, there is a possibility that near-infrared cut property is reduced, and therefore F is substantially not contained. Substantially not containing a fluorine atom means that, when the content of F contained in the glass is expressed as a percentage based on the content of the component elements other than F contained in the glass being set to 100% by mass, the content of F is less than 3% as a percentage.

[0117] In the phosphate glass of the present embodiment, in order to improve the weather resistance of the glass, SiO2, GeO2, ZrO2, SnO2, TiO2, CeO2, WO3, Y2O3, La2O3, Gd2O3, Yb2O3, and Nb2O5may be contained in a range of 5% or less. If the content of these components is 5% or less, there are less problems such as reduction in near-infrared cut property and reduction in transmission of short-wavelength infrared, and therefore it is preferable. The content of these components is preferably 4% or less, more preferably 3% or less, further preferably 2% or less, and still further preferably 1% or less.

[0118] Next, the components that can constitute the fluorophosphate glass and the suitable contents thereof will be described below. In the following description of the fluorophosphate glass, the content of each component and the total content are expressed in mass % unless otherwise specified.

[0119] In the fluorophosphate glass, P (phosphorus) is contained in the form of P2O5. P2O5is a main component of the fluorophosphate glass, and is a necessary component for improving the sharp cut-off in the near-infrared region. The content of P2O5is preferably 20% to 70%. If the content of P2O5is 20% or more, the effect thereof can be sufficiently obtained, and if the content of P2O5is 70% or less, there are less problems such as the glass becoming unstable and reduction in weather resistance. Therefore, the content of P2O5is more preferably 25% or more, further preferably 30% or more, still further preferably 33% or more, and most preferably 35% or more, and on the other hand, the content of P2O5is more preferably 60% or less, further preferably 55% or less, still further preferably 50% or less, and most preferably 45% or less. Note that, as a raw material of P2O5, phosphoric acid or a salt thereof is preferably used from the viewpoint of suppressing erosion of a platinum crucible and suppressing volatilization of components. 5+ 5+ 5+ 5+ 5+ 5+ 5+ Note that, as a raw material of P2O5, phosphoric acid or a salt thereof is preferably used from the viewpoint of suppressing erosion of a platinum crucible and suppressing volatilization of components.

[0120] In the fluorophosphate glass, F (fluorine) is contained in the form of F2. F2is a necessary component for stabilizing the glass and for improving weather resistance. In the present specification, the content of F2contained in the glass is expressed as a percentage based on the content of the component elements other than F2contained in the glass being set to 100% by mass. - - - ​​​​​​​​When other component elements are set to 100% by mass, the percentage of other added elements indicates the amount of F contained in the glass. - The content of F. - The preferred addition ratio, other than the content of [specific ingredient], is 3% to 60%.

[0121] If F - If the content of F is above 3% (excluding the added proportion), the weather resistance effect can be fully obtained. - If the content of [specific ingredient] is less than 60%, it is less likely to cause problems such as reduced transmittance in the visible light region, reduced absorption capacity in the near-infrared region, reduced sharpness, or reduced mechanical properties such as strength, hardness, and elastic modulus, or increased ultraviolet transmittance. - More preferably, the proportion of the additive is 4% or more; even more preferably, the proportion of the additive is 6% or more; even more preferably, the proportion of the additive is 8% or more; most preferably, the proportion of the additive is 10% or more; further preferably, the proportion of the additive is 50% or less; even more preferably, the proportion of the additive is 40% or less; even more preferably, the proportion of the additive is 30% or less; and most preferably, the proportion of the additive is 20% or less.

[0122] In fluorophosphate glass, Cu (copper) is present as Cu + or Cu 2+ It contains the form of Cu, but all of them are described in this specification. 2+ The content when it exists in the form of .

[0123] Cu 2+ It is a component used to improve absorption in the near-infrared region. Additionally, Cu... 2+ Cu has the property of attracting phosphate chains in glass to form cross-linked structures, thus strengthening the glass structure and improving its weather resistance and strength. 2+ The preferred content of Cu is 1% to 20%. 2+ When the content of Cu is less than 1%, the absorption capacity of the glass in the near-infrared region may decrease. 2+ Preferably, it is 2% or more, more preferably 3% or more, further preferably 4% or more, and even more preferably 5% or more. Additionally, when Cu... 2+ When the content of Cu exceeds 20%, the glass becomes unstable, and the risk of devitrification increases. 2+ Preferably, it is 18% or less, more preferably 14% or less, even more preferably 12% or less, and even more preferably 10% or less.

[0124] In addition, the total Cu content is the total amount of Cu in mass percentage, including monovalent, divalent, and other existing valences, in the total content of all components of fluorophosphate glass (excluding F). -The content of the total Cu amount is preferably in the range of 1 to 20% in the case where the content of CuO is set to 100%. When the total Cu amount is 1% or more, the effect of the absorption ability in the near infrared region can be sufficiently obtained, and when the total Cu amount is 20% or less, the decrease in the transmittance in the visible region can be suppressed. Note that the Cu + The content of CuO in % can be in the range of (Cu + / total Cu amount) x 100 [%] is in the range of 0.01 to 4.0%.

[0125] In the fluorophosphate glass, Al (aluminum) is contained in the form of Al 3+ Al 3+ is a component that forms the glass, and is a component for improving the strength of the glass, improving the weather resistance of the glass, and the like. If the content of Al 3+ is 1% or more, the effect thereof can be sufficiently obtained, and if the content of Al 3+ is 20% or less, problems such as the glass becoming unstable, or the absorption ability in the near infrared region, the sharp cutoff property decreasing, and the like do not easily occur. The content of Al 3+ is preferably in the range of 1 to 20%. The content of Al 3+ is more preferably 2% or more, further preferably 3% or more, more further preferably 4% or more, most preferably 5% or more, and more preferably 19% or less, further preferably 18% or less, more further preferably 15% or less, most preferably 13% or less.

[0126] Note that, as a raw material of Al 3+ , AlF3, Al2O3, Al(OH)3, and the like can be used, and among these, AlF3is preferably used from the viewpoint of not easily causing problems such as an increase in the melting temperature, the generation of unmelted material, and a decrease in the amount of F - to be input, and the glass becoming unstable.

[0127] Li (lithium) is a component for lowering the melting temperature of the glass, lowering the liquidus temperature of the glass, improving the weather resistance of the glass, stabilizing the glass, and the like. The content of Li + is preferably in the range of 0 to 30%. If the content of Li + is 30% or less, the glass does not easily become unstable. When Li is contained, the absorption ability in the near infrared region, the sharp cutoff property decreases, and therefore the content of Li + is more preferably 28% or less, further preferably 25% or less, more further preferably 20% or less, most preferably 10% or less. It is more preferably 0.5% or more, further preferably 1% or more, and further preferably 3% or more. When the alkali metal component is only Li +While weather resistance improves, absorption capacity and sharp cutoff in the near-infrared region decrease. Therefore, it is necessary to contain one or more ionic radicals with a radius greater than that of Li. + Large alkali metal content.

[0128] Sodium (Na) is used to lower the melting temperature of glass, lower the liquidus temperature of glass, and stabilize glass. + The preferred content of Na is 0% to 40%. + If the sodium content is below 40%, the glass is less likely to become unstable. + The content of [specific metal] is more preferably 30% or less, more preferably 25% or less, even more preferably 20% or less, and most preferably 10% or less. It is more preferably 0.5% or more, more preferably 1% or more, and even more preferably 3% or more. When the alkali metal component is only Na... + At times, it is possible to improve either weather resistance or enhance either high absorption capacity or sharp cutoff in the near-infrared region, with the improved properties varying depending on the composition of the system. However, it is difficult to simultaneously improve both properties. Therefore, to improve weather resistance, it is necessary to contain more than one of the following: Na. + In addition to alkali metals, to improve absorption and sharp cutoff in the near-infrared region, it is necessary to contain ionic radii larger than Na. + Large alkali metal content.

[0129] In fluorophosphate glass, K (potassium) is expressed as K + The form contains. K + It is a component that has the effects of lowering the melting temperature of glass, lowering the liquidus temperature of glass, improving absorption capacity in the near-infrared region, and sharp cutoff. As K... + The content of K is preferably 0% to 40%. + If the content is below 40%, the glass is less likely to become unstable, therefore it is preferred. + The content of [specific ingredient] is more preferably 0.5% or more, further preferably 1% or more, even more preferably 3% or more, and most preferably 5% or more. Additionally, when [specific ingredient] contains K... + At this point, weather resistance decreases, therefore it is preferable to have a content of 30% or less, more preferably 25% or less, even more preferably 20% or less, and most preferably 14% or less. When the alkali metal content is only K... + At this time, the absorption capacity and sharp cutoff in the near-infrared region increase, but the weather resistance decreases. Therefore, in order to improve weather resistance through the alkali mixing effect, it is necessary to contain more than one substance other than K. + Other than alkali metal components.

[0130] Rubidium (Rb) is a component that lowers the melting temperature and liquidus temperature of glass, enhances absorption in the near-infrared region, and provides sharp cutoff. As Rb...+ The content of Rb is preferably 0% to 20%. + If the content of Rb is below 20%, the glass is less likely to become unstable, therefore it is preferred. + When the weather resistance decreases, it is more preferable to be 15% or less, more preferably 10% or less, and even more preferably 5% or less. More preferably, it is 0.5% or more, more preferably 1% or more, and even more preferably 3% or more. When the alkali metal content is only Rb... + At this time, the absorption capacity and sharp cutoff in the near-infrared region increase, but the weather resistance decreases. Therefore, in order to improve weather resistance through the alkali mixing effect, it is necessary to contain more than one substance other than Rb. + Other than alkali metal components.

[0131] Cesium (Cs) is a component that lowers the melting temperature and liquidus temperature of glass, enhances its absorption capacity in the near-infrared region, and provides sharp cutoff. As a component of Cs... + The content of Cs is preferably 0% to 20%. + When the content of Cs is below 20%, the glass is less likely to become unstable, therefore it is preferred. + When the weather resistance decreases, it is more preferable to be 15% or less, more preferably 10% or less, and even more preferably 5% or less. More preferably, it is 0.5% or more, more preferably 1% or more, and even more preferably 3% or more. When the alkali metal content is only Cs... + At this time, the absorption capacity and sharp cutoff in the near-infrared region increase, but the weather resistance decreases. Therefore, in order to improve weather resistance through the alkali mixing effect, it is necessary to contain more than one substance other than Cs. + Other than alkali metal components.

[0132] R + (R + Selected from Li + Na + K + 、Rb + and Cs + One or more of these components are used to lower the melting temperature of glass, lower the liquidus temperature of glass, and stabilize glass. If R + The total quantity, i.e., Li + Na + K + 、Rb + and Cs + The total quantity (ΣR) + If R is above 1%, its full effect can be obtained; if R + When the total content is below 55%, the glass is less likely to become unstable, therefore it is preferred. Therefore, ΣR +The content of Mg is preferably 1 to 55%. More preferably, it is 5% or more, further preferably 10% or more, more further preferably 12% or more, most preferably 15% or more, and in addition, more preferably 45% or less, further preferably 40% or less, more further preferably 30% or less, most preferably 28% or less.

[0133] Mg 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, increasing the weather resistance of the glass, and the like. As the content of Mg 2+ , it is preferably 0 to 20%. If the content of Mg 2+ is 20% or less, problems such as the glass becoming unstable, the near-infrared cutoff property decreasing, and the like are less likely to occur. The content of Mg 2+ is more preferably 15% or less, further preferably 10% or less, and more further preferably 5% or less.

[0134] Ca 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, increasing the weather resistance of the glass, and the like. As the content of Ca 2+ , it is preferably 0 to 20%. If the content of Ca 2+ is 20% or less, problems such as the glass becoming unstable, the near-infrared cutoff property decreasing, and the like are less likely to occur. The content of Ca 2+ is more preferably 1% or more, further preferably 2% or more, and in addition, more preferably 18% or less, further preferably 15% or less, more further preferably 10% or less, and most preferably 7% or less.

[0135] Sr 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, increasing the weather resistance of the glass, and the like. As the content of Sr 2+ , it is preferably 0 to 30%. If the content of Sr 2+ is 30% or less, problems such as the glass becoming unstable, the near-infrared cutoff property decreasing, and the like are less likely to occur. The content of Sr 2+ is more preferably 1% or more, further preferably 2% or more, more further preferably 4% or more, and most preferably 5% or more, and in addition, more preferably 25% or less, further preferably 20% or less, more further preferably 16% or less, and most preferably 14% or less.

[0136] Ba is a component for lowering the melting temperature of the glass, lowering the liquidus temperature of the glass, stabilizing the glass, increasing the absorption ability of light in the near-infrared region, increasing the sharp cutoff property in the near-infrared region, and the like. As the content of Ba 2+ , it is preferably 0 to 40%. If the content of Ba 2+The content of Ba is preferably 40% or less. If the content of Ba is 40% or less, it is difficult for the glass to become unstable and the like. Ba 2+ The content of Ba is more preferably 1% or more, further preferably 5% or more, more further preferably 10% or more, and still more preferably 35% or less, further preferably 30% or less, and more further preferably 20% or less.

[0137] R 2+ (R 2+ is one or more components selected from the group consisting of Mg 2+ , Ca 2+ , Sr 2+ , and Ba 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. If the total amount of R 2+ , that is, the total amount of Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ (∑R 2+ ) is 1% or more, the effects thereof can be sufficiently obtained, and if the total amount of R 2+ is 50% or less, the glass is less likely to become unstable. Therefore, the content of ∑R 2+ is preferably 1% to 50%. More preferably, it is 5% or more, further preferably 10% or more, more further preferably 15% or more, and most preferably 20% or more, and still more preferably 45% or less, further preferably 40% or less, more further preferably 35% or less, and most preferably 32% or less.

[0138] Zn (zinc) has the effects of lowering the melting temperature of the glass, lowering the liquidus temperature of the glass, and the like. The content of Zn 2+ is preferably 0% to 20%. If the content of Zn 2+ is 20% or less, it is difficult for the glass to become unstable, the melting property of the glass to deteriorate, the near-infrared cut property to decrease, and the like. The content of Zn 2+ is more preferably 15% or less, further preferably 10% or less, and more further preferably 5% or less.

[0139] The content of P 5+ / ∑R" (R" is one or more components selected from the group consisting of Al 3+ , Mg 2+ , and Li + , and ∑R" is the total amount of R") is preferably 3.0 to 7.5.

[0140] P 5+ is a component for improving the sharp cut property in the near-infrared region, but also has the effect of decreasing the weather resistance. In addition, Al 3+ , Li +Mg + Each is a component having an effect of improving weather resistance.

[0141] Therefore, by adjusting the proportion of the content of P 5+ to the sum of R" to be 7.5 or less, the weather resistance of the glass can be improved. In addition, by adjusting the proportion of the content of P 5+ to the sum of R" to be 3.0 or more, the sharp cut-off property of the glass in the near-infrared region can be maintained at a high level. The proportion of the content of P 5+ to the sum of R" is more preferably 3.5 or more, further preferably 4.0 or more, still further preferably 4.5 or more, and more preferably 7.0 or less, further preferably 6.5 or less, still further preferably 6.0 or less, and most preferably 5.5 or less.

[0142] In order to stabilize the glass, B (boron) can be contained in a range of 20% or less. If the content of B 3+ is 20% or less, problems such as deterioration of the weather resistance of the glass and reduction of the near-infrared cut-off property are less likely to occur. The content of B 3+ is more preferably 15% or less, further preferably 10% or less, still further preferably 8% or less, and most preferably 5% or less.

[0143] In the fluorophosphate glass, in order to improve the weather resistance of the glass, SiO2, GeO2, ZrO2, SnO2, TiO2, CeO2, WO3, Y2O3, La2O3, Gd2O3, Yb2O3, and Nb2O5 can be contained in a range of 10% or less. If the content of these components is 10% or less, problems such as generation of devitrification foreign matter in the glass and reduction of the near-infrared cut-off property are less likely to occur. The content of these components is preferably 4% or less, more preferably 3% or less, further preferably 2% or less, and still further preferably 1% or less.

[0144] Fe2O3, Cr2O3, Bi2O3, NiO, V2O5, MnO2, and CoO are components that reduce the transmittance of light in the visible light region by being present in the glass. Therefore, it is preferable that these components are not substantially contained in the glass. Here, not substantially contained in the glass means not contained except for inevitable impurities, and means not intentionally added. Specifically, it means that the content of these components is about 100 mass ppm or less in the glass, respectively.

[0145] The thickness of the glass is preferably 3 mm or less, more preferably 2 mm or less, and further preferably 1 mm or less from the viewpoint of easiness of optical design when assembled in a camera module, and the thickness of the glass is preferably 0.05 mm or more, and more preferably 0.1 mm or more from the viewpoint of the strength of the element and the necessity of obtaining the desired optical properties.

[0146] <Barrier film>

[0147] The filter of the present embodiment is provided with a barrier film 1 and a barrier film 2 on both main surfaces of the glass.

[0148] In the case where the glass is phosphate glass, the barrier film 1 and the barrier film 2 each independently contain one or more selected from TiO2, Nb2O5, Ta2O5, and HfO2.

[0149] In the case where the glass is fluorophosphate glass, the barrier film 1 and the barrier film 2 each independently contain one or more selected from TiO2, Al2O3, Nb2O5, Ta2O5, and HfO2.

[0150] TiO2, Al2O3, Nb2O5, Ta2O5, and HfO2are each highly resistant to water, and by the presence of the barrier film configured of this between the glass and the dielectric multilayer film, it is possible to suppress elution of the glass due to the influence of moisture. From the viewpoint of improving moisture resistance, in the case where the glass is phosphate glass, the barrier film preferably contains TiO2, and in the case where the glass is fluorophosphate glass, the barrier film preferably contains at least one of TiO2and Al2O3.

[0151] Note that, from the viewpoint of the property of being lower than inorganic materials in terms of suppressing the entry of moisture, a resin material is not preferable as the material of the barrier film 1 and the barrier film 2.

[0152] In the case where the glass is phosphate glass, the barrier film preferably contains one or more selected from TiO2, Nb2O5, Ta2O5, and HfO2at a rate of 80 mol% or more in total, more preferably 90 mol% or more, further preferably 95 mol% or more, and particularly preferably 100 mol%.

[0153] Here, the barrier film can contain one or more selected from TiO2, Nb2O5, Ta2O5, and HfO2at 80 mol% or more alone, or can contain two or more materials selected from TiO2, Nb2O5, Ta2O5, and HfO2at 80 mol% or more in total.

[0154] In the case where the glass is fluorophosphate glass, the barrier film preferably contains one or more selected from TiO2, Al2O3, Nb2O5, Ta2O5, and HfO2at a rate of 80 mol% or more in total, more preferably 90 mol% or more, further preferably 95 mol% or more, and particularly preferably 100 mol%.

[0155] Here, the barrier film can contain 80 mol% or more of one or more selected from the group consisting of TiO2, Al2O3, Nb2O5, Ta2O5, and HfO2, or can contain 80 mol% or more in total of two or more selected from the group consisting of TiO2, Al2O3, Nb2O5, Ta2O5, and HfO2.

[0156] In addition, the barrier film can contain a material other than TiO2, Al2O3, Nb2O5, Ta2O5, and HfO2, without impairing water resistance. For example, from the viewpoint of adjusting the refractive index of the barrier film, SiO2may be contained. On the other hand, a layer containing silicon (Si) can possibly reduce adhesion to a glass substrate, and thus it is preferable not to contain it as much as possible. In the case of containing a material other than TiO2, Al2O3, Nb2O5, Ta2O5, and HfO2, it is preferable to be 20 mol% or less in total. In addition, from the viewpoint of improving the water resistance of the optical filter, it is preferable not to contain a material other than an oxide of a metal of aluminum (Al), titanium (Ti), niobium (Nb), tantalum (Ta), and hafnium (Hf).

[0157] In addition, the physical film thickness of the barrier film 2 and the dielectric multilayer film 2 in the direction of incidence of external light is preferably a specific condition. That is, when the film including the barrier film 2 and the dielectric multilayer film 2 is taken as the laminated film 2, X represented by the following formula (1) is preferably 35% or more.

[0158] X (%) = {A / (B-C)} x 100 (1)

[0159] In formula (1), when each layer contained in the laminated film 2 is evaluated by QWOT represented by the following formula (2), A (nm) is the total thickness of the dielectric layer having a QWOT of less than 2 and a refractive index of 1.9 or less contained in the above laminated film 2. B (nm) is the total physical film thickness of the laminated film 2. C (nm) is the total thickness of the layer having a QWOT of 2 or more in the laminated film 2.

[0160] Here, QWOT (Quarter Wave Optical Thickness) is an optical film thickness of λ / 4 of the wavelength, and is calculated by the following formula (2).

[0161] QWOT = (thickness (nm) of the layer as an object / 550 (nm)) x 4 x (refractive index of the layer as an object at 550 nm) (2)

[0162] The above X means the level of barrier properties of the laminated film 2, and by controlling X, the reflectance of the barrier film 2 and the dielectric multilayer film 2 combined together can be controlled, and the effect of high barrier properties can be obtained.

[0163] If X is 35% or more, then, for example, the maximum reflectance at wavelengths of 450 nm to 750 nm when the light absorption layer side is the incident direction, as shown in the spectral characteristics of the filter (i-9), is preferably within the desired range. As described above, by suppressing the maximum reflectance when the light absorption layer side is the incident direction, unwanted light entering the sensor can be suppressed. In other words, by having a barrier film 2 that satisfies X being 35% or more and a dielectric multilayer film 2, the reflectance at the light absorption layer side can be controlled.

[0164] X is more preferably 50% or more, and even more preferably 70% or more.

[0165] The overall thickness B (nm) of the laminated film 2 is obtained by adding the physical thickness of the barrier film 2 to the physical thickness of the dielectric multilayer film 2.

[0166] The total thickness C (nm) of the layers with a QWOT of 2 or higher in the laminated film 2 is obtained by adding the physical film thicknesses of the layers with a QWOT of 2 or higher contained in the barrier film 2 and the dielectric multilayer film 2.

[0167] The total thickness A (nm) of the layers in the stacked film 2 with a QWOT less than 2 and a refractive index less than 1.9 is obtained by adding the physical film thicknesses of the layers in the barrier film 2 and the dielectric multilayer film 2 with a QWOT less than 2 and a refractive index less than 1.9.

[0168] From the perspective of improving the moisture resistance and reliability of the filter, the thickness of the barrier film 1 is preferably 10 nm or more, and more preferably 20 nm or more.

[0169] From the perspective of improving the moisture resistance and reliability of the filter, the thickness of the barrier film 2 is preferably 10 nm or more, and more preferably 20 nm or more.

[0170] The combined physical film thickness of the barrier film 1 and the dielectric multilayer film 1 is preferably 1 μm or more, and more preferably 2 μm or more. This thickness is preferred from the viewpoint of improving the water resistance of the filter and preventing film deformation in the event of glass surface deterioration.

[0171] The combined physical film thickness of the barrier film 2 and the dielectric multilayer film 2 is preferably 100 nm or more, and more preferably 200 nm or more. This range is preferred from the viewpoints of improving the water resistance of the filter and preventing film deformation in the event of glass surface deterioration.

[0172] Barrier films can be formed using vacuum film-forming processes such as CVD, sputtering, and vacuum evaporation, as well as wet film-forming processes such as spraying and immersion.

[0173] In the case where the layered film 2 has a layer containing SiO2, X' represented by the following formula (3) can be 35% or greater in the layered film 2. X' (%) is more preferably 50% or greater, and further preferably 70% or greater.

[0174] X' (%) = {A' / (B' - C')} x 100 (3)

[0175] Note that in formula (3), A' (nm) is the total thickness of the SiO2 layer having a thickness of 180 nm or less in the layered film 2, B' (nm) is the total thickness of the layered film 2, C' (nm) is the total thickness of the SiO2 layer having a thickness of greater than 180 nm in the layered film 2.

[0176] <Dielectric multilayer film>

[0177] The optical filter of the present embodiment has a dielectric multilayer film 1 on the barrier film 1 side and a dielectric multilayer film 2 on the barrier film 2 side. Details will be described later, but in the case where the film including the barrier film 1 and the dielectric multilayer film 1 is taken as a layered film 1, and in the case where the film including the barrier film 2 and the dielectric multilayer film 2 is taken as a layered film 2, at least one of the layered film 1 and the layered film 2 is preferably designed as a reflection film that reflects a part of near-infrared light (hereinafter also referred to as "NIR reflection film"), and more preferably the layered film 1 is a NIR reflection film from the viewpoint of shielding of near-infrared light.

[0178] The NIR reflection film preferably has, for example, wavelength selectivity that allows transmission of visible light and mainly reflects near-infrared light. The NIR reflection film can also be appropriately designed to reflect light in a wavelength range other than near-infrared light, such as near-ultraviolet light.

[0179] The dielectric multilayer film is a layered body of dielectric films having different refractive indexes. More specifically, a low-refractive-index dielectric film (low-refractive-index film), a medium-refractive-index dielectric film (medium-refractive-index film), and a high-refractive-index dielectric film (high-refractive-index film) can be cited, and the dielectric multilayer film is composed of two or more of these layered. By combining a plurality of dielectric films having different spectral characteristics when transmission in a desired wavelength band is allowed and a desired wavelength band is selected, it is possible to adjust the reflection characteristics.

[0180] The high refractive index material preferably has a refractive index of 1.8 or more and 3.0 or less, more preferably 1.8 or more and 2.8 or less, and further preferably 1.8 or more and 2.5 or less at a wavelength of 500 nm. As the high refractive index material, for example, Ta2O5, TiO2, TiO, and Nb2O5 can be mentioned. As other commercially available products, OS50 (Ti3O5), OS10 (Ti4O7), OA500 (a mixture of Ta2O5 and ZrO2), OA600 (a mixture of Ta2O5 and TiO2), and the like manufactured by Canon Optron Co., Ltd. can be mentioned. Among them, TiO2 is preferable from the viewpoints of film formability, reproducibility, stability, and the like of the refractive index.

[0181] The medium refractive index material is a material having a relatively low refractive index compared to the high refractive index material, and preferably has a refractive index of 1.5 or more and 2.0 or less, more preferably 1.5 or more and 1.95 or less, and further preferably 1.5 or more and 1.8 or less at a wavelength of 500 nm. As the medium refractive index material, ZrO2, Nb2O5, Al2O3, HfO2, OM-4, OM-6 (a mixture of Al2O3 and ZrO2), OA-100 manufactured by Canon Optron Co., Ltd., H4, M2 (alumina-lanthana) manufactured by Merck Co., Ltd., and the like can be mentioned. Among them, an Al2O3-based compound and a mixture of Al2O3 and ZrO2 are preferable from the viewpoints of film formability, reproducibility, stability, and the like of the refractive index.

[0182] The low refractive index material is a material having a relatively low refractive index compared to the medium refractive index material, and preferably has a refractive index of 1.3 or more and 1.7 or less, more preferably 1.3 or more and 1.65 or less, and further preferably 1.4 or more and 1.5 or less at a wavelength of 500 nm. As the low refractive index material, for example, SiO2, SiO x N y、 MgF2, and the like. As other commercially available products, S4F, S5F (a mixture of SiO2 and AlO2) manufactured by Canon Optron Co., Ltd. can be mentioned. Among them, SiO2 is preferable from the viewpoints of reproducibility, stability, and economy of film formability.

[0183] The laminated film 1 including the barrier film 1 and the dielectric multilayer film 1 is preferably designed so that the optical filter satisfies the spectral characteristic (i-6), that is, when the dielectric multilayer film 1 side is taken as the incident direction, the maximum reflectance at an incident angle of 5 degrees in the wavelength range of 850 nm to 1200 nm is 85% or more. In addition, it is preferably designed so that the optical filter satisfies the spectral characteristic (i-10), that is, when the dielectric multilayer film 1 side is taken as the incident direction, the average reflectance at an incident angle of 5 degrees in the wavelength range of 800 nm to 1100 nm is 95% or more. The spectral characteristic (i-6) and the spectral characteristic (i-10) of the optical filter substantially reflect the reflection characteristics of the laminated film 1. That is, the laminated film 1 preferably can reflect light in the near-infrared light region in a wide range.

[0184] The laminated film 1 preferably has an average transmittance of 93% or more in the wavelength range of 440 nm to 500 nm at an incident angle of 0 degrees, and an average transmittance of 84% or more in the wavelength range of 440 nm to 500 nm at an incident angle of 60 degrees.

[0185] In addition, the laminated film 1 preferably has a maximum transmittance of 90% or more in the wavelength range of 430 nm to 750 nm at an incident angle of 0 degrees, and a maximum transmittance of 70% or more in the wavelength range of 400 nm to 670 nm at an incident angle of 60 degrees.

[0186] From the viewpoint of being able to reduce the incident angle dependence of the spectral characteristics, and also from the viewpoint of having a function of protecting the glass, the film thickness (physical film thickness) of the dielectric multilayer film 1 is preferably 1 μm or more, and more preferably 1.5 μm or more, and from the viewpoint of productivity and suppressing reflection ripples in the visible light region, the film thickness (physical film thickness) of the dielectric multilayer film 1 is preferably 10 μm or less.

[0187] With the dielectric multilayer film 1 as a whole being a thick film of 1 μm or more, the reflection characteristics are less likely to vary with the incident angle. This is because the thicker the film, the more sluggish the interference.

[0188] The dielectric multilayer film 1 preferably satisfies the following characteristic (iiA-1).

[0189] (iiA-1) includes a high refractive index layer H A , a medium refractive index layer M A , and a low refractive index layer L A , the high refractive index layer H A contains a high refractive index material having a refractive index of 1.8 or more and 3.0 or less at a wavelength of 500 nm, the medium refractive index layer M A contains a medium refractive index material having a refractive index that is relatively lower than that of the high refractive index material and a refractive index of more than 1.5 and less than 2.0 at a wavelength of 500 nm, and the low refractive index layer L AThis includes low-refractive-index materials with a refractive index relatively low compared to medium-refractive-index materials, and a refractive index of 1.3 or higher and 1.7 or lower at a wavelength of 500 nm, and possessing properties derived from (H... A / M A / L A / M A ) n The repeating stacked structure represented by (n is a natural number greater than 2) (where, in the intermediate refractive index layer M) A Includes a high refractive index layer H A and low refractive index layer L A In the case of [the membrane], it is considered an equivalent membrane.

[0190] By satisfying the characteristic (iiA-1) of the dielectric multilayer film 1, it is easy to obtain a multilayer film that can reflect light in the near-infrared region over a wide range, which is preferred in this respect.

[0191] Furthermore, n is preferably a natural number of 2 or more, more preferably 3 or more, and even more preferably 4 or more, with larger values ​​being more preferred. If n is within this range, then a repeating, layered structure (H) is appropriately present. A / M A / L A / M A This allows us to obtain the desired reflection characteristics.

[0192] It should be noted that multiple repeating stacked structures (H) A / M A / L A / M A They can be continuous or separate.

[0193] The total number of layers in the dielectric multilayer film 1 is preferably 20 or more, more preferably 30 or more, and even more preferably 35 or more. However, when the total number of layers increases, warping or the film thickness may occur. Therefore, the total number of layers is preferably 100 or less, more preferably 75 or less, and even more preferably 60 or less.

[0194] The laminated film 2, comprising the barrier film 2 and the dielectric multilayer film 2, is preferably designed such that the filter satisfies spectral characteristics (i-7) and (i-8), namely, when the light-absorbing layer side is taken as the incident direction, at an incident angle of 60 degrees, the maximum reflectance at wavelengths of 450 nm to 750 nm is 20% or less, and at an incident angle of 60 degrees, the maximum reflectance at wavelengths of 750 nm to 1200 nm is 42% or less. The spectral characteristics (i-7) and (i-8) of the filter are essentially the reflectance characteristics of the laminated film 2. That is, the laminated film 2 preferably has low reflectance characteristics in the visible light region and the near-infrared region.

[0195] From the viewpoint of reducing the dependence of the spectral characteristics on the incident angle, and the viewpoint of also having a function of protecting the glass, the film thickness (physical film thickness) of the dielectric multilayer film 2 is preferably 100 nm or more, more preferably 150 nm or more, and from the viewpoint of productivity and suppressing reflection ripples in the visible region, the film thickness (physical film thickness) of the dielectric multilayer film 2 is preferably 10 μm or less.

[0196] In addition, as described above, the dielectric multilayer film 2 has a function of protecting the glass together with the barrier film 2 and the light-absorbing layer. From this viewpoint, it is preferable that the film not be easily peeled off, and that the system be strong.

[0197] The total number of layers of the dielectric multilayer film 2 is preferably 60 layers or less, more preferably 30 layers or less, and further preferably 6 layers or less.

[0198] The present optical filter can have a dielectric multilayer film 3 on at least one outermost surface, preferably the surface of the light-absorbing layer. From the viewpoint of reducing the generation of ripples in the visible region, the dielectric multilayer film 3 is preferably designed to be, for example, a near-infrared antireflection film (NIR antireflection film).

[0199] The total number of layers of the dielectric multilayer film 3 is preferably 60 layers or less, more preferably 30 layers or less, and further preferably 15 layers or less, and is preferably 8 layers or less. In order to suppress reflection in the visible region even if the incident angle changes, it is preferable that the film not be a film that reflects a specific wavelength, but rather a film that has a low reflectance in the entire wavelength band.

[0200] In addition, the film thickness (physical film thickness) of the dielectric multilayer film 3 as a whole is preferably 200 nm to 1000 nm.

[0201] In the formation of the dielectric multilayer film, for example, a vacuum film formation process such as a CVD method, a sputtering method, a vacuum evaporation method, a wet film formation process such as a spray method, a dipping method, or the like can be used.

[0202] <Light-absorbing layer>

[0203] The optical filter of the present embodiment has a light-absorbing layer provided on the dielectric multilayer film 2. The light-absorbing layer contains a near-infrared absorbing pigment having a maximum absorption wavelength in the range of 680 nm to 800 nm, and is able to compensate for a wavelength range that is not shielded by the reflection characteristics of the dielectric multilayer film by absorption.

[0204] From the viewpoint of being able to absorb light in the near infrared region over a wide range and being able to suppress a decrease in visible light transmittance, it is preferable to combine two or more kinds of near infrared absorbing pigments having different maximum absorption wavelengths in the range of 680 nm to 800 nm, and more preferable to combine one or more kinds of near infrared absorbing pigments having a maximum absorption wavelength in the range of 700 nm to 740 nm and one or more kinds of near infrared absorbing pigments having a maximum absorption wavelength in the range of 740 nm to 800 nm.

[0205] As the near infrared absorbing pigment, at least one kind selected from the group consisting of squarylium pigments, phthalocyanine pigments, cyanine pigments, dithiol metal complex pigments, azo pigments, polymethine pigments, benzophthalide pigments, naphthoquinone pigments, anthraquinone pigments, indophenol pigments, pyrylium pigments, thiopyrylium pigments, croconium pigments, tetra-dehydrocholine pigments, triphenylmethane pigments, ammonium pigments, and diimmonium pigments is preferable. As the near infrared absorbing pigment, at least one kind selected from the group consisting of squarylium pigments, phthalocyanine pigments, and cyanine pigments is preferable. Among these pigments, from the viewpoint of the spectrum, squarylium pigments and cyanine pigments are preferable, and from the viewpoint of durability, phthalocyanine pigments are preferable. As the near infrared absorbing pigment, at least one kind selected from the group consisting of squarylium pigments, phthalocyanine pigments, and cyanine pigments is preferable. Among these pigments, from the viewpoint of the spectrum, squarylium pigments and cyanine pigments are preferable, and from the viewpoint of durability, phthalocyanine pigments are preferable. As the near infrared absorbing pigment, at least one kind selected from the group consisting of squarylium pigments, phthalocyanine pigments, and cyanine pigments is preferable. Among these pigments, from the viewpoint of the spectrum, squarylium pigments and cyanine pigments are preferable, and from the viewpoint of durability, phthalocyanine pigments are preferable.

[0206] As the near infrared absorbing pigment, at least one kind selected from the group consisting of squarylium pigments, phthalocyanine pigments, and cyanine pigments is preferable. Among these pigments, from the viewpoint of the spectrum, squarylium pigments and cyanine pigments are preferable, and from the viewpoint of durability, phthalocyanine pigments are preferable. As the near infrared absorbing pigment, at least one kind selected from the group consisting of squarylium pigments, phthalocyanine pigments, and cyanine pigments is preferable. Among these pigments, from the viewpoint of the spectrum, squarylium pigments and cyanine pigments are preferable, and from the viewpoint of durability, phthalocyanine pigments are preferable. As the near infrared absorbing pigment, at least one kind selected from the group consisting of squarylium pigments, phthalocyanine pigments, and cyanine pigments is preferable. Among these pigments, from the viewpoint of the spectrum, squarylium pigments and cyanine pigments are preferable, and from the viewpoint of durability, phthalocyanine pigments are preferable.

[0207] In addition, the light absorbing layer is preferably a resin film containing the pigment and a resin.

[0208] The content of the near infrared absorbing pigment in the light absorbing layer is preferably 0.1 to 25 parts by mass, and more preferably 0.3 to 15 parts by mass, with respect to 100 parts by mass of the resin. Note that, in the case of combining two or more kinds of compounds, the above content is the total of each compound.

[0209] The light absorbing layer can contain other pigments in addition to the above-described near infrared absorbing pigment. As the other pigments, pigments having a maximum absorption wavelength in the range of 370 to 440 nm in a resin (UV pigments) are preferable. Thereby, light in the near ultraviolet region can be effectively shielded.

[0210] As the UV pigments, the following can be exemplified: oxazole pigments, merocyanine pigments, cyanine pigments, naphthalimide pigments, oxadiazole pigments, oxazine pigments, oxazolidine pigments, naphthalic acid pigments, styryl pigments, anthracene pigments, cyclic carbonyl pigments, triazole pigments, and the like. Among these, merocyanine pigments are particularly preferable. In addition, one kind can be used alone, or two or more kinds can be used in combination.

[0211] As the resin in the light-absorbing layer, there is no limitation as long as it is a transparent resin, and one or more kinds of transparent resins selected from the group consisting of polyester resins, acrylic resins, epoxy resins, ene-thiol resins, polycarbonate resins, polyether resins, polyarylate resins, polysulfone resins, polyethersulfone resins, poly-p-phenylene resins, polyarylene ether phosphine oxide resins, polyamide resins, polyimide resins, polyamide-imide resins, polyolefin resins, cyclic olefin resins, polyurethane resins, and polystyrene resins, etc. can be used. These resins can be used singly or in combination of two or more kinds.

[0212] From the viewpoints of the spectral characteristics, glass transition temperature (Tg), and adhesion of the light-absorbing layer, it is preferable to use one or more kinds of resins selected from the group consisting of polyimide resins, polycarbonate resins, polyester resins, and acrylic resins.

[0213] In the case where a plurality of compounds are used as the near-infrared absorbing colorant or other colorants, they can be contained in the same light-absorbing layer, or alternatively, can be contained in different light-absorbing layers, respectively.

[0214] The light-absorbing layer can be formed by dissolving or dispersing the colorant, the resin, or the raw material components of the resin and the components as needed in a solvent to prepare a coating liquid, coating it on the medium multilayer film 2, and drying and curing it as needed. Alternatively, the coating liquid can be coated on a peelable support used only when the light-absorbing layer is formed, and then the light-absorbing layer can be laminated on the medium multilayer film 2. Further, the solvent can be a dispersion medium capable of stably dispersing or a solvent capable of dissolving.

[0215] Further, in order to improve voids caused by minute air bubbles, depressions caused by the attachment of foreign matter, shrinkage holes in the drying process, etc., the coating liquid can contain a surfactant. Further, in the coating of the coating liquid, for example, dip coating, flow coating, spin coating, or the like can be used. Further, in the case where the coating liquid contains the raw material components of the transparent resin, further curing treatment such as heat curing or photocuring is performed.

[0216] Further, the light-absorbing layer can also be produced in a film shape by extrusion molding. The obtained film-shaped absorbing layer is laminated on the medium multilayer film 2 and integrated by heat pressure bonding or the like, whereby the present optical filter can be produced.

[0217] The optical filter can have one light-absorbing layer, or can have two or more light-absorbing layers. In the case where there are two or more light-absorbing layers, each layer can have the same constitution, or can be different, and further, can be formed on separate medium multilayer films, or can be overlaid on one medium multilayer film in two or more layers.

[0218] The thickness of the light absorbing layer is preferably 10 μm or less, more preferably 5 μm or less, from the viewpoint of the in-plane film thickness distribution and the appearance quality of the coated substrate. The thickness of the light absorbing layer is preferably 0.5 μm or more, from the viewpoint of exhibiting the desired spectral characteristics with an appropriate pigment concentration. Note that in the case where the optical filter has two or more light absorbing layers, the total thickness of the light absorbing layers is preferably within the above range.

[0219] The optical filter of the present embodiment can include, for example, a constituent element (layer) that generates absorption using inorganic fine particles or the like that control the transmission and absorption of light in a specific wavelength range. Specific examples of the inorganic fine particles include ITO (indium tin oxide), ATO (antimony-doped tin oxide), cesium tungstate, lanthanum boride, and the like. ITO fine particles and cesium tungstate fine particles have high visible light transmittance and have light absorbing properties in a wide range of infrared wavelength regions greater than 1200 nm, and thus can be used in cases where shielding of such infrared light is required.

[0220] <Imaging device>

[0221] The imaging device of the present embodiment preferably includes the optical filter of the present embodiment described above. The imaging device preferably further includes a solid-state imaging element and an imaging lens. The optical filter of the present embodiment can be disposed, for example, between the imaging lens and the solid-state imaging element, or can be used by being directly attached to the solid-state imaging element, the imaging lens, or the like of the imaging device via an adhesive layer. By including the present optical filter, which has excellent visible light transmittance, has specific near-infrared light shielding properties, and has a spectral curve that is not easily shifted even at high angles of incidence, an imaging device having excellent color reproducibility even for light at high angles of incidence can be obtained.

[0222] When the optical filter is installed in an imaging device, it is generally preferable to arrange the dielectric multilayer film 1 on the lens side (the side on which external light is incident), and the dielectric multilayer film 2 on the sensor side.

[0223] As described above, the present specification discloses the following optical filter and the like.

[0224] [1] An optical filter including: a glass; a dielectric multilayer film 1 and a dielectric multilayer film 2 provided on both sides of the glass; a barrier film 1 provided between the glass and the dielectric multilayer film 1; a barrier film 2 provided between the glass and the dielectric multilayer film 2; and a light absorbing layer provided on the dielectric multilayer film 2, wherein the glass is a phosphate glass having near-infrared absorbing properties and substantially containing no fluorine atoms, or a fluorophosphate glass having near-infrared absorbing properties and containing fluorine atoms, the light absorbing layer contains a near-infrared absorbing pigment having a maximum absorption wavelength in the range of 680 nm to 800 nm, In the case where the glass is the phosphate glass, the barrier film 1 and the barrier film 2 each independently contain one or more selected from the group consisting of TiO2, Nb2O5, Ta2O5, and HfO2, In the case where the glass is the fluorophosphate glass, the barrier film 1 and the barrier film 2 each independently contain one or more selected from the group consisting of TiO2, Al2O3, Nb2O5, Ta2O5, and HfO2, The optical filter satisfies all of the following spectral properties (i-1) to (i-3), (i-6): (i-1) The average transmittance at a wavelength of 440 nm to 500 nm is 80% or more at an incident angle of 0 degrees, and the average transmittance at a wavelength of 440 nm to 500 nm is 70% or more at an incident angle of 60 degrees; (i-2) The average transmittance at a wavelength of 750 nm to 1000 nm is 1% or less at an incident angle of 0 degrees, and the average transmittance at a wavelength of 750 nm to 1000 nm is 1% or less at an incident angle of 60 degrees; (i-3) In a spectral transmittance curve at an incident angle of 0 degrees, a wavelength IR10 at which the transmittance is 10% (0deg) in a range of 600 nm to 700 nm; (i-6) When the medium multilayer film 1 side is taken as an incident direction, the maximum reflectance at a wavelength of 850 nm to 1200 nm is 85% or more at an incident angle of 5 degrees.

[0225] [2] The optical filter according to [1], wherein the optical filter satisfies the following spectral property (i-4) and spectral property (i-5): (i-4) In a spectral transmittance curve at an incident angle of 0 degrees, a wavelength IR10 at which the transmittance is 10% in a range of 600 nm to 700 nm (0deg) and a wavelength IR10 at which the transmittance is 10% in a range of 600 nm to 700 nm in a spectral transmittance curve at an incident angle of 60 degrees (60deg) have an absolute value of 20 nm or less; (i-5) The transmittance at a wavelength of 1100 nm is 1% or less at an incident angle of 0 degrees, and the transmittance at a wavelength of 1100 nm is 3% or less at an incident angle of 60 degrees.

[0226] [3] The optical filter according to [1] or [2], wherein the optical filter satisfies the following spectral property (i-7) and spectral property (i-8): (i-7) When the light-absorbing layer side is taken as an incident direction, the maximum reflectance at a wavelength of 450 nm to 750 nm is 20% or less at an incident angle of 60 degrees; (i-8) The maximum reflectance at a wavelength of 750 nm to 1200 nm is 42% or less at an incident angle of 60 degrees when the light absorbing layer side is taken as the incident direction.

[0227] [4] The optical filter according to any one of [1] to [3], wherein, when a film including the barrier film 2 and the dielectric multilayer film 2 is taken as a laminated film 2, X represented by the following formula (1) is 35% or more, X (%) = {A / (B-C)} x 100 (1) Here, when each layer included in the laminated film 2 is evaluated by QWOT represented by the following formula (2), A (nm) is a total thickness of a layer having a QWOT of less than 2 and a refractive index of 1.9 or less in the laminated film 2, QWOT = (thickness (nm) of a layer as an object / 550 (nm)) x 4 x (refractive index at a wavelength of 550 nm of the layer as the object) (2) B (nm) is a total thickness of the laminated film 2, C (nm) is a total thickness of a layer having a QWOT of 2 or more in the laminated film 2.

[0228] [5] The optical filter according to any one of [1] to [4], wherein the optical filter satisfies the following spectral characteristic (i-9): (i-9) The maximum reflectance at a wavelength of 450 nm to 750 nm is 7.5% or less at an incident angle of 5 degrees when the light absorbing layer side is taken as the incident direction.

[0229] [6] The optical filter according to any one of [1] to [5], wherein the optical filter satisfies the following spectral characteristic (i-10): (i-10) The average reflectance at a wavelength of 800 nm to 1100 nm is 95% or more at an incident angle of 5 degrees when the dielectric multilayer film 1 side is taken as the incident direction.

[0230] [7] The optical filter according to any one of [1] to [6], wherein the phosphate glass substantially does not contain a fluorine atom, the phosphate glass contains, in terms of mol% on an oxide basis: 40% to 75% of P2O5, 10% to 30% of Al2O3, 0.1% to 30% of ΣR2O (where R2O is one or more components selected from Li2O, Na2O, K2O, Rb2O, and Cs2O, and ΣR2O represents a total content of R2O), 0 to 30% of ΣR'O (where R'O is one or more components selected from the group consisting of CaO, MgO, BaO, SrO, and ZnO, and ΣR'O represents the total content of R'O), 2 to 30% of CuO.

[0231] [8] The optical filter according to any one of [1] to [6], wherein the fluorophosphate glass contains, in mass%: 20 to 70% of P 5+ 、 1 to 20% of Al 3+ 、 0 to 30% of Li + 、 0 to 40% of Na + 、 0 to 40% of K + 、 0 to 20% of Rb + 、 0 to 20% of Cs + 、 0 to 20% of Mg 2+ 、 0 to 20% of Ca 2+ 、 0 to 30% of Sr 2+ 、 0 to 40% of Ba 2+ 、 1 to 55% of ΣR + (R + is one or more components selected from the group consisting of Li + , Na + , K + , Rb + , and Cs + ), 1 to 50% of ΣR 2+ (R 2+ is one or more components selected from the group consisting of Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ ), 1 to 20% of Cu 2+ , and 0 to 20% of Zn 2+ , when the component elements other than F - contained in the glass are taken as 100 mass%, the fluorophosphate glass contains 3 mass% to 60 mass% of F - in terms of an addition ratio.

[0232] [9] The optical filter according to any one of [1] to [8], wherein the glass has

[0233] a transmittance of 80% or more at a wavelength of 420 nm, a transmittance of 6% or less at a wavelength of 800 nm, a transmittance of 25% or less at a wavelength of 1200 nm.

[0234]

[10] The optical filter according to any one of [1] to [9], wherein the dielectric multilayer film 1 satisfies the following property (iiA-1): (iiA-1) the dielectric multilayer film 1 contains a high refractive index layer H A , a medium refractive index layer M A , and a low refractive index layer L A , the high refractive index layer H A contains a high refractive index material having a refractive index of 1.8 or more and 3.0 or less at a wavelength of 500 nm, the medium refractive index layer M A contains a medium refractive index material having a refractive index relatively lower than the high refractive index material and a refractive index of 1.5 or more and 2.0 or less at a wavelength of 500 nm, the low refractive index layer L A contains a low refractive index material having a refractive index relatively lower than the medium refractive index material and a refractive index of 1.3 or more and 1.7 or less at a wavelength of 500 nm, and the dielectric multilayer film 1 has a repeating layer structure represented by (H A / M A / L A / M A ) n (n is a natural number of 2 or more) (wherein, in the case where the medium refractive index layer M A contains a high refractive index layer H A and a low refractive index layer L A , it is regarded as an equivalent film).

[0235]

[11] The optical filter according to any one of [1] to

[10] , wherein, in the case where the glass is the phosphate glass, the barrier film 1 and the barrier film 2 contain TiO2, in the case where the glass is the fluorophosphate glass, the barrier film 1 and the barrier film 2 each independently contain at least one of TiO2and Al2O3.

[0236]

[12] The filter according to any one of [1] to

[11] , wherein the light-absorbing layer comprises one or more near-infrared absorbing pigments having a maximum absorption wavelength in the range of greater than or equal to 700 nm and less than 740 nm and one or more near-infrared absorbing pigments having a maximum absorption wavelength in the range of 740 nm and more than 800 nm.

[0237]

[13] An imaging device, wherein the imaging device comprises any one of [1] to

[12] filters.

[0238] Example

[0239] Next, the invention will be described in more detail through examples.

[0240] The ultraviolet-visible spectrophotometer (manufactured by Hitachi High Technology Co., Ltd., model UH-4150) was used to measure the various spectral characteristics.

[0241] It should be noted that the spectral characteristics without a clearly stated incident angle are the values ​​measured at an incident angle of 0 degrees (the direction perpendicular to the main surface of the filter).

[0242] The pigments used in each example are described below.

[0243] Compound 1 (cyanin compound): synthesized based on Dyes and pigments 73 (2007) 344-352.

[0244] Compound 2 (particulate cyanide compound): synthesized based on German Patent Publication No. 10109243.

[0245] Compound 3 (squamous acid) Salt compounds: synthesized based on International Publication No. 2017 / 135359.

[0246] Compound 4 (squamous acid) Salt compounds: synthesized based on International Publication No. 2014 / 088063 and International Publication No. 2016 / 133099.

[0247] Compound 5 (particulate cyanide compound): synthesized based on German Patent Publication No. 10109243.

[0248]

[0249] It should be noted that compounds 1, 3, and 4 are near-infrared absorbing pigments (NIR pigments), while compounds 2 and 5 are near-ultraviolet absorbing pigments (UV pigments). The maximum absorption wavelengths of each pigment are shown in Table 7 below.

[0250] <The spectral properties of the glasses>

[0251] The glasses shown below were prepared.

[0252] As a phosphate glass or a fluorophosphate glass, the raw materials were weighed and mixed in a manner to become the contents shown in Table 1 or Table 2 in terms of mol% or mass% on an oxide basis, and were put in a crucible with an internal volume of about 400 mL, and were melted for 2 hours under a reducing atmosphere. Then, fining and stirring were performed, and casting was performed into a rectangular mold of 100 mm in length x 80 mm in width x 20 mm in height which was preheated to about 300°C to 500°C, and then slow cooling was performed at about 1°C / minute, whereby a glass of a sample of a plate-shaped body on which both faces were optically polished was obtained.

[0253] The spectral properties of each glass are shown in Table 1 and Table 2 below.

[0254] In addition, the spectral transmittance curves of each glass are shown in Figure 3 and Figure 4 respectively.

[0255] [Table 1]

[0256] [Table 2]

[0257] As shown above, it was found that the glasses 1, 3, 4 (phosphate glasses) and 2 (fluorophosphate glass) have excellent visible light transmittance, and are capable of absorbing a wide range of near-infrared light from 800 nm to 1200 nm.

[0258] <Reliability test 1 of the glasses>

[0259] A test piece of 5 mm in length, 5 mm in width, and 0.29 mm in thickness of the glass 1 manufactured above was prepared, and a barrier film was formed by layering the materials shown in Table 3 below on both main faces by vapor deposition.

[0260] A high temperature and high humidity test was performed on the glass substrate with the barrier film under the following conditions.

[0261] The glass substrate with the barrier film was left to stand in an environment of a temperature of 85°C and a relative humidity of 85% for the time shown in Table 3, and then the end face was observed from the main face side under a metal microscope at 200 times, and the degree of deterioration was evaluated. The distance from the end face of the most deteriorated site was measured, and evaluation was performed based on the following criteria. B or more was determined to be acceptable.

[0262] A: End face deterioration was less than 150 μm

[0263] B: end surface deterioration is 150 μm or more and less than 200 μm

[0264] C: end surface deterioration is 200 μm or more

[0265] The evaluation results are shown in Table 3 below.

[0266] Note that Examples 1-1 to 1-2 are reference examples, and Examples 1-3 to 1-5 are reference comparative examples.

[0267] [Table 3]

[0268] From the above results, for the glass 1 (phosphate glass), the durability of the barrier film made of titanium oxide or tantalum is excellent, and titanium oxide is particularly preferable. On the other hand, for the barrier film made of aluminum oxide, silicon dioxide, or zirconium oxide, end surface deterioration is confirmed, and durability is not obtained.

[0269] [Reliability test 2 of glass]

[0270] A test piece of 5 mm in length, 5 mm in width, and 0.29 mm in thickness of the above-mentioned manufactured glass 1 was prepared, and TiO2was alternately layered on both main surfaces by evaporation, thereby forming a barrier film. Then, SiO2and TiO2were alternately layered on the surface of each barrier film by evaporation, thereby forming a dielectric multilayer film A or B of the constitution shown in Table 5. Note that film number 1 is the layer in contact with the barrier film.

[0271] For the obtained test piece, the degree of end surface deterioration was evaluated by the same method and criteria as in the reliability test 1 of glass.

[0272] The evaluation results are shown in Table 4 below.

[0273] Note that Examples 1-6 to 1-7 are reference examples.

[0274] [Table 4]

[0275] [Table 5]

[0276] From the results of the above-mentioned Examples 1-6 to 1-7, for all of the phosphate glasses, the durability of the barrier film could be confirmed.

[0277] In addition, the durability of Example 1-6, in which the total film thickness of the barrier film and the dielectric multilayer film is large, was higher.

[0278] [Reliability test 3 of glass]

[0279] A test piece of 5 mm in length, 5 mm in width, and 0.225 mm in thickness of the above-mentioned manufactured glass 2 (fluorophosphate glass) was layered with TiO2or Al2O3by vapor deposition on both main surfaces, thereby forming a barrier film. Then, SiO2and TiO2were alternately layered by vapor deposition on the surface of each barrier film, thereby forming a dielectric multilayer film A or B of the constitution shown in Table 6. Note that film number 1 is the layer in contact with the barrier film.

[0280] A high-temperature high-humidity test was performed on the obtained test piece under the following conditions.

[0281] The glass substrate with the barrier film was left to stand in an environment of 85°C in temperature and 85% in relative humidity for the time shown in Table 3, and then the end surface was observed from the main surface side under a metal microscope at 200 times, and the degree of deterioration was evaluated. The distance from the end surface of the deepest deteriorated site was measured, and the evaluation was performed based on the following criteria. C or more was judged as acceptable.

[0282] A: End surface deterioration of less than 100 μm

[0283] B: End surface deterioration of 100 μm or more and less than 150 μm

[0284] C: End surface deterioration of 150 μm or more and less than 250 μm

[0285] D: End surface deterioration of 250 μm or more

[0286] The evaluation results are shown in the following Table 6.

[0287] Note that Examples 1-8 to 1-9 are reference examples, and Example 1-10 is a reference comparative example.

[0288] [Table 6]

[0289] From the results of the above Examples 1-8 to 1-9, it was found that durability could be confirmed in fluorophosphate glass using either of TiO2or Al2O3as the barrier film, and Example 1-8 in which TiO2was used was more preferable.

[0290] [Spectral properties of light-absorbing layer]

[0291] The pigments of Compound 1 to Compound 5 were dissolved in polyimide resin C-3G30G manufactured by Mitsubishi Gas Chemical Company, Inc., and mixed at the concentrations shown in the following Table 7, respectively, and stirred and dissolved at 50°C for 2 hours, thereby obtaining coating liquids. The obtained coating liquids were applied on alkali glass (manufactured by SCHOTT, D263 glass, thickness 0.2 mm) by a spin coating method, and a light-absorbing layer 1 and a light-absorbing layer 2 each having a film thickness of 1 μm were formed.

[0292] For the obtained light absorbing layer 1, light absorbing layer 2, the spectral transmittance curve and the spectral reflectance curve in the wavelength range of 350 nm to 1200 nm were measured using an ultraviolet-visible spectrophotometer.

[0293] The results are shown in Table 7 below.

[0294] In addition, the spectral transmittance curve of the light absorbing layer is shown in Figure 5 .

[0295] [Table 7]

[0296] [Example 2-1: Spectral characteristics of optical filter]

[0297] On both main surfaces of glass 1 (phosphate glass), TiO2was alternately layered by evaporation in the same composition as in Example 1-1, thereby forming barrier film 1, barrier film 2, respectively.

[0298] On the surface of barrier film 1, SiO2and TiO2were alternately layered by evaporation, thereby forming a dielectric multilayer film 1A of the constitution shown in Table 8.

[0299] On the surface of barrier film 2, SiO2and TiO2were alternately layered by evaporation, thereby forming a dielectric multilayer film 2A of the constitution shown in Table 11.

[0300] On the surface of barrier film 2, a resin solution was applied in the same composition as in light absorbing layer 1, and sufficiently heated to remove the organic solvent, thereby forming a light absorbing layer 1 of 1 μm in thickness.

[0301] On the surface of the light absorbing layer, SiO2and TiO2were alternately layered by evaporation, thereby forming a dielectric multilayer film 3A (antireflection film) of the constitution shown in Table 13.

[0302] Thus, optical filter 2-1 was manufactured.

[0303] [Example 2-2]

[0304] Except that a dielectric multilayer film 2B of the constitution shown in Table 11 was formed instead of dielectric multilayer film 2A, and the thickness of barrier film 2 was changed to the values shown in Table 14, the same operation as in Example 2-1 was performed, thereby manufacturing optical filter 2-2.

[0305] [Example 2-3]

[0306] On both main surfaces of glass 2 (fluorophosphate glass), Al2O3was layered by evaporation in the same composition as in Example 1-9, thereby forming barrier film 1, barrier film 2, respectively.

[0307] On the surface of the barrier film 1, SiO2and TiO2were alternately stacked by evaporation, thereby forming a dielectric multilayer film IB having the constitution shown in Table 8.

[0308] On the surface of the barrier film 2, SiO2and TiO2were alternately stacked by evaporation, thereby forming a dielectric multilayer film 2C having the constitution shown in Table 11.

[0309] On the surface of the barrier film 2-2, a resin solution was applied in the same composition as the light-absorbing layer 1, and the organic solvent was removed by heating, thereby forming a light-absorbing layer having a thickness of 1 μm.

[0310] On the surface of the light-absorbing layer, SiO2and TiO2were alternately stacked by evaporation, thereby forming a dielectric multilayer film 3A (antireflection film) having the constitution shown in Table 13.

[0311] Thus, the optical filter 2-3 was produced.

[0312] <Example 2-4>

[0313] The same operation as in Example 2-1 was performed except that a dielectric multilayer film 1C having the constitution shown in Table 9 was formed instead of the dielectric multilayer film IA, thereby producing an optical filter 2-4.

[0314] <Example 2-5>

[0315] The same operation as in Example 2-3 was performed except that a dielectric multilayer film ID having the constitution shown in Table 10 was formed instead of the dielectric multilayer film IB, thereby producing an optical filter 2-5.

[0316] <Example 2-6>

[0317] The same operation as in Example 2-1 was performed except that a dielectric multilayer film 2D having the constitution shown in Table 11 was formed instead of the dielectric multilayer film 2A, and the thickness of the barrier film 2 was changed to the value shown in Table 15, thereby producing an optical filter 2-6.

[0318] <Example 2-7>

[0319] The same operation as in Example 2-1 was performed except that a dielectric multilayer film 2E having the constitution shown in Table 12 was formed instead of the dielectric multilayer film 2A, and the thickness of the barrier film 2 was changed to the value shown in Table 15, thereby producing an optical filter 2-7.

[0320] <Example 2-8>

[0321] The same operation as in Example 2-1 was performed except that a dielectric multilayer film 2F having the constitution shown in Table 12 was formed instead of the dielectric multilayer film 2A, and the thickness of the barrier film 2 was changed to the value shown in Table 15, thereby producing an optical filter 2-8.

[0322] Example 2-9

[0323] On both main surfaces of glass 1 (phosphate glass), Al2O3 was layered by vapor deposition in the same composition as Example 1-9, thereby forming barrier film 1 and barrier film 2, respectively.

[0324] On the surface of barrier film 1, SiO2 and TiO2 were alternately layered by vapor deposition, thereby forming a dielectric multilayer film IB of the constitution shown in Table 8.

[0325] On the surface of barrier film 2, SiO2 and TiO2 were alternately layered by vapor deposition, thereby forming a dielectric multilayer film 2G of the constitution shown in Table 12.

[0326] On the surface of barrier film 2, a resin solution was applied in the same composition as light absorbing layer 1, and the organic solvent was removed by sufficient heating, thereby forming a light absorbing layer of 1 μm in thickness.

[0327] On the surface of the light absorbing layer, SiO2 and TiO2 were alternately layered by vapor deposition, thereby forming a dielectric multilayer film 3A (antireflection film) of the constitution shown in Table 13.

[0328] Thus, optical filter 2-9 was produced.

[0329] Example 2-10

[0330] On both main surfaces of glass 3 (phosphate glass), TiO2 was layered by vapor deposition in the same composition as Example 1-8, thereby forming barrier film 1 and barrier film 2, respectively.

[0331] On the surface of barrier film 1, SiO2 and TiO2 were alternately layered by vapor deposition, thereby forming a dielectric multilayer film IE of the constitution shown in Table 10.

[0332] On the surface of barrier film 2, SiO2 and TiO2 were alternately layered by vapor deposition, thereby forming a dielectric multilayer film 2H of the constitution shown in Table 12.

[0333] On the surface of barrier film 2, a resin solution was applied in the composition of light absorbing layer 2, and the organic solvent was removed by sufficient heating, thereby forming a light absorbing layer of 1 μm in thickness.

[0334] On the surface of the light absorbing layer, SiO2 and TiO2 were alternately layered by vapor deposition, thereby forming a dielectric multilayer film 3B (antireflection film) of the constitution shown in Table 13.

[0335] Thus, optical filter 2-10 was produced.

[0336] Example 2-11

[0337] Example 2-11 was produced in the same manner as in Example 2-10, except that the glass 4 shown in Table 1 was used instead of the glass 3.

[0338] [Table 8]

[0339] [Table 9]

[0340] [Table 10]

[0341] [Table 11]

[0342] [Table 12]

[0343] [Table 13]

[0344] For each of the above obtained optical filters, the spectral transmittance curve at an incident angle of 0 degree and 60 degrees and the spectral reflectance curve at an incident angle of 5 degrees and 60 degrees in a wavelength range of 350 nm to 1200 nm were measured using an ultraviolet-visible spectrophotometer.

[0345] Further, for the optical filters of Example 2-10 and Example 2-11, the degree of deterioration of the end surface was evaluated by the same method and criteria as in the reliability test 1 for the glass.

[0346] According to the obtained data of the spectral characteristics, each of the characteristics shown in Tables 14 to 16 below was calculated.

[0347] Note that the calculation method of X of the laminated film 2 including the dielectric multilayer film 2A and the barrier film 2 is specifically shown. Here, the refractive index of SiO2 is 1.9 or less, and the refractive index of TiO2 is greater than 1.9.

[0348] The total thickness A (nm) of the dielectric layer containing QWOT less than 2 and having a refractive index of 1.9 or less in the laminated film 2 can be calculated from the sum of the physical film thickness of the SiO2 film of film number 1 and the physical film thickness of the SiO2 film of film number 3 constituting the dielectric multilayer film 2A shown in Table 11.

[0349] The total thickness B (nm) of the laminated film 2 can be calculated from the sum of the physical film thickness of the dielectric multilayer film 2A as a whole and the physical film thickness of the barrier film 2.

[0350] The physical film thickness of the SiO2 film of No. 5 shown in Table 11, which constitutes the dielectric multilayer film 2A, corresponds to the total thickness C (nm) of the layers having QWOT of 2 or more in the laminated film 2.

[0351] X was calculated from the above.

[0352] The spectral transmittance curve and the spectral reflectance curve of the optical filter of Example 2-1 are shown in Figure 6 .

[0353] The spectral transmittance curve and the spectral reflectance curve of the optical filter of Example 2-3 are shown in Figure 7 .

[0354] Note that Examples 2-1 to 2-11 are examples.

[0355] [Table 14]

[0356] [Table 15]

[0357] [Table 16]

[0358] From the above results, it was found that the optical filters of Examples 2-1 to 2-11 are excellent in transmittance in the visible light region and shielding property in the near-infrared light region even at a high incident angle.

[0359] Further, the reflectance on the light absorbing layer side of the optical filters of Examples 2-1 to 2-6 was suppressed to be low even at a high incident angle. This is because the laminated film 2 (dielectric multilayer film 2 + barrier film 2) having X of 35% or more was used.

[0360] In addition, it was found that the optical filters of Examples 2-4 and 2-5 can reflect light in the entire near-infrared light region of 800 nm to 1100 nm in a wide range. This is because the dielectric multilayer film 1C or 1D having high light shielding property in the near-infrared light region was used.

[0361] In addition, according to the results of the reliability test of the optical filters of Examples 2-10 and 2-11, it was confirmed that the durability was maintained even when the thickness of the laminated film 2 (multilayer film 2 + barrier film 2) as a whole was 200 nm or less.

[0362] The present application has been described with reference to specific embodiments, but various changes or modifications can be applied without departing from the spirit and scope of the present application, which will be apparent to those skilled in the art. This application is based on Japanese Patent Application (Japanese Patent Application No. 2023-135695) filed on August 23, 2023, the contents of which are incorporated herein by reference.

[0363] Industrial applicability

[0364] The filter of the present application is excellent in visible light transmittance and near-infrared light shielding property. It can be used in information acquisition devices such as cameras and sensors for conveyors, which have been recently advanced in performance.

[0365] Explanation of reference numerals

[0366] 1A, 1B Filter

[0367] 10 Glass

[0368] 11, 12 Barrier film

[0369] 21, 22, 23 Dielectric multilayer film

[0370] 30 Light absorbing layer

Claims

1. A light filter comprising: glass, a dielectric multilayer film 1 and a dielectric multilayer film 2 disposed on both sides of the glass, a barrier film 1 disposed between the glass and the dielectric multilayer film 1, a barrier film 2 disposed between the glass and the dielectric multilayer film 2, and a light-absorbing layer disposed on the dielectric multilayer film 2, wherein, The glass is a phosphate glass that has near-infrared absorption properties and is substantially free of fluorine atoms, or a fluorophosphate glass that has near-infrared absorption properties and contains fluorine atoms. The light-absorbing layer contains near-infrared absorbing pigments with maximum absorption wavelengths in the range of 680nm to 800nm. When the glass is the phosphate glass, the barrier film 1 and the barrier film 2 each independently contain one or more selected from TiO2, Nb2O5, Ta2O5, and HfO2. When the glass is the fluorophosphate glass, the barrier film 1 and the barrier film 2 each independently contain one or more selected from TiO2, Al2O3, Nb2O5, Ta2O5, and HfO2. The filter satisfies all of the following spectral characteristics (i-1) to (i-3), (i-6): (i-1) At an incident angle of 0 degrees, the average transmittance of wavelengths from 440 nm to 500 nm is above 80%, and at an incident angle of 60 degrees, the average transmittance of wavelengths from 440 nm to 500 nm is above 70%. (i-2) At an incident angle of 0 degrees, the average transmittance of wavelengths from 750 nm to 1000 nm is less than 1%, and at an incident angle of 60 degrees, the average transmittance of wavelengths from 750 nm to 1000 nm is less than 1%. (i-3) In the spectral transmittance curve at an incident angle of 0 degrees, the wavelength IR10 when the transmittance is 10% (0deg) Within the range of 600nm to 700nm; (i-6) When the incident direction is the 1 side of the dielectric multilayer film, the maximum reflectivity of the wavelength 850nm to 1200nm is 85% or more at an incident angle of 5 degrees.

2. The filter according to claim 1, wherein, The filter satisfies the following spectral characteristics (i-4) and (i-5): (i-4) In the spectral transmittance curve at an incident angle of 0 degrees, the wavelength IR10 at which the transmittance is 10% in the range of 600 nm to 700 nm. (0deg) The wavelength IR10, where the transmittance is 10% in the range of 600 nm to 700 nm, is compared with the spectral transmittance curve at an incident angle of 60 degrees. (60deg) The absolute value of the difference is less than 20nm; (i-5) At an incident angle of 0 degrees, the transmittance at a wavelength of 1100 nm is less than 1%, and at an incident angle of 60 degrees, the transmittance at a wavelength of 1100 nm is less than 3%.

3. The filter according to claim 1, wherein, The filter satisfies the following spectral characteristics (i-7) and spectral characteristics (i-8): (i-7) When the light-absorbing layer side is taken as the incident direction, the maximum reflectivity of wavelengths from 450 nm to 750 nm is less than 20% at an incident angle of 60 degrees. (i-8) When the light absorption layer side is taken as the incident direction, the maximum reflectivity of wavelength 750nm to 1200nm is less than 42% at an incident angle of 60 degrees.

4. The filter according to claim 1, wherein, When the membrane comprising the barrier membrane 2 and the dielectric multilayer membrane 2 is used as the laminated membrane 2, X, as expressed by the following formula (1), is 35% or more. X(%)={A / (BC)}×100 (1) Here, when evaluating each layer contained in the laminated film 2 using QWOT as expressed by the following equation (2), A(nm) is the total thickness of the layers in the laminate 2 that have a QWOT less than 2 and a refractive index less than 1.

9. QWOT = (thickness of the layer as the object (nm) / 550 (nm)) × 4 × (refractive index of the layer as the object at wavelength 550 nm) (2) B(nm) is the overall thickness of the laminated film 2. C(nm) is the total thickness of layers in the laminated film 2 with a QWOT of 2 or more.

5. The filter according to claim 1, wherein, The filter satisfies the following spectral characteristics (i-9): (i-9) When the light absorption layer side is taken as the incident direction, the maximum reflectivity of wavelengths from 450nm to 750nm is less than 7.5% at an incident angle of 5 degrees.

6. The filter according to claim 1, wherein, The filter satisfies the following spectral characteristics (i-10): (i-10) When the incident direction is the 1 side of the dielectric multilayer film, the average reflectivity of the wavelength 800nm ​​to 1100nm is 95% or more at an incident angle of 5 degrees.

7. The filter according to claim 1, wherein, The phosphate glass does not actually contain fluorine atoms. The phosphate glass contains, in molar percentages based on oxides: 40%–75% of P2O5, 10%–30% Al2O3, 0.1% to 30% ΣR2O (wherein R2O is one or more components selected from Li2O, Na2O, K2O, Rb2O and Cs2O, and ΣR2O represents the total content of R2O), 0%–30% ΣR'O (where R'O is one or more components selected from CaO, MgO, BaO, SrO, and ZnO, and ΣR'O represents the total content of R'O), 2% to 30% CuO.

8. The filter according to claim 1, wherein, The fluorophosphate glass contains, by weight%, the following percentages: 20%–70% of P 5+ , 1% to 20% Al 3+ , Li from 0% to 30% + 、 0% to 40% Na + , 0%~40% of K + , 0% to 20% of Rb + , 0%~20% Cs + , 0%~20% Mg 2+ , 0%~20% Ca 2+ , 0%~30% Sr 2+ 、 0% to 40% Ba 2+ , 1% to 55% of ΣR + (R + Selected from Li + Na + K + 、Rb + and Cs + (one or more components) 1% to 50% of ΣR 2+ (R 2+ Selected from Mg 2+ Ca 2+ 、Sr 2+ and Ba 2+ (one or more components) 1%–20% Cu 2+ ,and 0% to 20% of Zn 2+ , In addition to F, the glass contains - When other constituent elements are set at 100% by mass, the fluorophosphate glass contains 3% to 60% by mass of F, based on the proportion of other added elements. - .

9. The filter according to claim 1, wherein, Based on a plate thickness of 0.2mm, the glass... The transmittance at a wavelength of 420nm is over 80%. The transmittance at a wavelength of 800 nm is less than 6%. The transmittance at a wavelength of 1200nm is less than 25%.

10. The filter according to claim 1, wherein, The dielectric multilayer film 1 satisfies the following characteristics (iiA-1): (iiA-1) The dielectric multilayer film 1 includes a high refractive index layer H A Middle refractive index layer M A and low refractive index layer L A The high refractive index layer H A The medium refractive index layer M comprises a high refractive index material with a refractive index of 1.8 or higher and 3.0 or lower at a wavelength of 500 nm. A The low-refractive-index layer L comprises a medium-refractive-index material with a relatively low refractive index compared to the high-refractive-index material and a refractive index of 1.5 or higher and 2.0 or lower at a wavelength of 500 nm. A The dielectric multilayer film 1 comprises a low refractive index material having a relatively low refractive index compared to the intermediate refractive index material, and a refractive index of 1.3 or higher and 1.7 or lower at a wavelength of 500 nm. A / M A / L A / M A ) n The repeating stacked structure represented by (n is a natural number greater than 2) (where, in the intermediate refractive index layer M) A Includes a high refractive index layer H A and low refractive index layer L A In the case of [the membrane], it is considered an equivalent membrane.

11. The filter according to claim 1, wherein, When the glass is the phosphate glass, the barrier film 1 and barrier film 2 contain TiO2. When the glass is the fluorophosphate glass, the barrier film 1 and the barrier film 2 each independently contain at least one of TiO2 and Al2O3.

12. The filter according to claim 1, wherein, The light-absorbing layer includes one or more near-infrared absorbing pigments having a maximum absorption wavelength in the range of 700 nm or greater and less than 740 nm, and one or more near-infrared absorbing pigments having a maximum absorption wavelength in the range of 740 nm or greater and less than 800 nm.

13. An imaging device, wherein, The imaging device comprises the filter according to any one of claims 1 to 12.

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