JP7630760B2 - Substrate, optical filter and optical sensor device - Google Patents

Description

The present invention relates to a substrate, an optical filter, and an optical sensor device.

Known infrared absorbing filters (near infrared absorbing filters) include filters made of vapor-deposited glass, filters made of phosphate glass containing metal ions, and filters having an infrared absorbing layer formed on a resin substrate such as cycloolefin.
However, these glass infrared absorbing filters have problems such as poor near infrared absorbing performance, and resin substrates such as cycloolefin have poor heat resistance.

In order to solve these problems, many filters have been proposed in recent years as infrared absorbing filters (for example, Patent Documents 1 to 4). Specific examples include plastic infrared absorbing filters that include an infrared absorbing layer formed by coating a resin substrate such as polyester with a coating liquid in which a binder resin such as polyester resin, acrylic resin, polycarbonate resin, styrene-based resin, amorphous polyolefin resin, polyisocyanate resin, polyarylate resin, or cellulose-based resin, an infrared absorbing dye, and a visible light absorbing dye for color tone correction are dissolved or uniformly dispersed in a solvent, and then drying and removing the solvent.

These plastic infrared absorbing filters are required to exhibit infrared absorbing ability at thinner film thicknesses, so the dye in the thin infrared absorbing layer that is formed must be present in a highly concentrated and uniformly dispersed state in the binder resin to prevent uneven distribution, aggregation, precipitation on the surface, etc. Furthermore, the dye dispersed in the binder resin must be durable for a long period of time and must not deteriorate due to reactions between the dyes or due to environmental factors such as heat, light, and humidity.

Infrared absorbing filters are also known in which an infrared absorbing layer containing a binder resin and a dye is formed on a glass substrate, but in this case too, the dye dispersed in the binder resin must have long-term durability.

Japanese Patent Application Publication No. 11-116826 JP 2000-227515 A Patent No. 3308545 Patent No. 5936299

However, conventional near-infrared absorbing filters do not have sufficient performance, particularly in terms of heat durability, and there is room for improvement in this regard.

The present invention has been made in consideration of the above, and aims to provide a substrate and an optical filter in which a compound having near-infrared absorbing ability (near-infrared absorbing compound) is uniformly dispersed and which has excellent durability against heat.

As a result of intensive research aimed at solving the above problems, the present inventors have found that the above problems can be solved by the following configuration examples, and have thus completed the present invention.
A configuration example of the present invention is as follows.
In the present invention, the expression "A to B" or the like expressing a numerical range is synonymous with "A or more, B or less", and includes A and B in the numerical range. In addition, in the present invention, a wavelength of A to B nm represents characteristics at a wavelength resolution of 1 nm in a wavelength region of A nm or more and B nm or less.

[1] A substrate having a near infrared absorbing layer containing a resin and a near infrared absorbing compound,
The substrate has a retention rate of 80% or more of the maximum absorbance in the wavelength region of 700 to 1000 nm before and after heat treatment in air at 150° C. for 600 hours.

[2] The substrate described in [1] has a transmission wavelength band in the wavelength range of 430 to 580 nm, in which the transmittance of light incident at an incident angle of 0° is 40% or more.

[3] The substrate according to [1] or [2], wherein the resin comprises at least one selected from the group consisting of polycarbonate and polysulfone.

[4] The substrate according to any one of [1] to [3], wherein the near infrared absorbing compound includes at least one compound selected from the group consisting of a squarylium-based compound, a phthalocyanine-based compound, a dithiol-based compound, a diimmonium-based compound, and a polymethine-based compound (the polymethine-based compound is a compound other than a squarylium-based compound).

[5] The substrate according to any one of [1] to [4], wherein the near infrared absorbing compound includes a polymethine compound.

[6] The near infrared absorbing compound,
A polymethine compound,
The substrate according to any one of [1] to [5], comprising a near infrared absorbing compound having an absorption maximum wavelength λmax in a wavelength region of 680 to 1000 nm in an absorption spectrum measured in a wavelength range of 300 to 1000 nm using a solution of the near infrared absorbing compound dissolved in dichloromethane (provided that the near infrared absorbing compound is a compound other than a polymethine compound).

[7] The substrate according to any one of [1] to [6], wherein the resin contains a polycarbonate having a repeating unit represented by the following formula (1):

［式中、Ｚは、該Ｚが結合している炭素原子と共に、置換基を有していてもよい炭素数５～１５の環状炭化水素基を構成し、Ｒ^1aおよびＲ^1bは同一または異なり、炭素数１～２０のアルキル基、炭素数５～２０のシクロアルキル基、炭素数６～１０のアリール基、炭素数７～１４のアラルキル基、炭素数２～６のアルケニル基、炭素数１～１０のアルコキシ基、炭素数２～１０のアシル基、炭素数２～４のアルコキシカルボニル基、ハロゲン原子、ニトロ基またはシアノ基であり、ｍ１およびｍ２は同一または異なり、０～４の整数である。］

[In the formula, Z, together with the carbon atom to which Z is bonded, constitutes a cyclic hydrocarbon group having 5 to 15 carbon atoms which may have a substituent; R ^1a and R ^1b are the same or different and are an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 5 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 14 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an acyl group having 2 to 10 carbon atoms, an alkoxycarbonyl group having 2 to 4 carbon atoms, a halogen atom, a nitro group, or a cyano group; and m1 and m2 are the same or different and are an integer of 0 to 4.]

[8] The substrate according to any one of [1] to [7], further comprising a compound having a maximum absorption wavelength λmax in the wavelength range of 350 to 420 nm.

[9] The substrate is
a base material having a glass substrate and the near infrared absorbing layer;
A substrate having the near-infrared absorbing layer and a resin layer other than the near-infrared absorbing layer, or
The substrate according to any one of [1] to [8], which is any substrate consisting of only the near infrared absorbing layer.

[10] An optical filter having a dielectric multilayer film on at least one surface of the substrate described in any one of [1] to [9].

[11] The optical filter according to [10], which has an average transmittance of 70% or less for light with an incident angle of 0° in the wavelength range of 750 to 900 nm.

[12] A first transmission wavelength band having a transmittance of 40% or more for light having an incident angle of 0° in a wavelength range of 400 to 700 nm,
A second transmission wavelength band having a transmittance of 40% or more for light having an incident angle of 0° in a wavelength region of 750 to 1000 nm,
Having a light blocking band (Xa) between the first transmission wavelength band and the second transmission wavelength band,
The optical filter according to [10] or [11].

[13] The optical filter according to any one of [10] to [12], which is for use in an optical sensor device.
[14] An optical sensor device comprising the optical filter according to [13].

According to the present invention, a substrate and an optical filter having excellent durability against heat, in which a compound having near-infrared absorbing ability (near-infrared absorbing compound) is uniformly dispersed, can be provided. Also, according to the present invention, a substrate having excellent durability that does not cause thermal deterioration over a long period of time, and an optical filter, particularly a near-infrared absorbing filter, having excellent color shooting properties and including the substrate can be provided.
Furthermore, according to the present invention, it is possible to provide an optical filter which has excellent heat durability and near-infrared sensing ability, and which allows for the mass production of filters (chips) of a desired size smaller than a single large filter (hereinafter also referred to as "excellent for mass production").

FIG. 1A is a cross-sectional schematic diagram illustrating an example of a substrate according to one embodiment of the present invention. FIG. 1B is a cross-sectional schematic view illustrating an example of a substrate according to one embodiment of the present invention. FIG. 1C is a schematic cross-sectional view illustrating an example of a substrate according to one embodiment of the present invention. FIG. 2 is a spectral transmittance curve of the substrate of Example 5. FIG. 3 is a spectral transmittance curve of the optical filter of Example 5. FIG. 4 is a schematic diagram of a punching blade.

<Base material>
A substrate according to one embodiment of the present invention (hereinafter also referred to as "the substrate") has a near infrared absorbing layer containing a resin and a near infrared absorbing compound, and has a retention rate of 80% or more of the maximum absorbance in a wavelength range of 700 to 1000 nm before and after heat treatment in air at 150°C for 600 hours.
The present substrate is suitably used for a near-infrared absorbing filter.

The retention rate of the maximum absorbance in the wavelength region of 700 to 1000 nm (hereinafter also referred to as "dye retention rate") before and after heat treatment of this substrate in air at 150°C for 600 hours is 80% or more, preferably 81% or more, and more preferably 82% or more.
The present substrate having the dye retention rate within the above range can be said to be a substrate having excellent durability against heat, and which is free from thermal deterioration over a long period of time.
Specifically, the dye retention rate can be calculated by the method described in the Examples.

It is desirable for the present substrate to have a transmission wavelength band in the wavelength region of 430 to 580 nm, in which the transmittance of light incident on the surface of the present substrate at an incident angle of 0° is preferably 40% or more, more preferably 60% or more, and even more preferably 70% or more.
The present substrate having the above-mentioned transmission wavelength band can be suitably used with a dual bandpass filter (DBPF) such as a near-infrared cut filter (NIR-CF) or a visible light-near-infrared selective transmission filter.

The average transmittance (Tb_AVE) of light having a wavelength of 430 to 580 nm incident on the surface of the substrate at an incident angle of 0° is preferably 60% or more, more preferably 70% or more. Since a higher average transmittance is preferable, the upper limit is not particularly limited and may be 100%.
The present substrate having Tb_AVE in the above range can be said to have a high visible light transmittance, and since it can further suppress the decrease in visible light transmittance while sufficiently cutting light of wavelengths in the near-infrared region that are to be cut, it can be suitably used for NIR-CF and DBPF.

In the present invention, the average transmittance for wavelengths A to B nm is a value calculated by measuring the transmittance at each wavelength in 1 nm increments from A nm to B nm, and dividing the sum of the transmittances by the number of measured transmittances (wavelength range, B-A+1).
In the present invention, when referring to a surface of a base material, a substrate or an optical filter, the surface refers to the surface having the largest area (main surface) of the base material, a substrate or an optical filter.

The maximum transmittance (Tb_MAX) of light having a wavelength of 700 to 1000 nm incident on the surface of the substrate at an incident angle of 0° is preferably 60% or more, more preferably 70% or more, and the upper limit is not particularly limited and may be 100%.
The present substrate having Tb_MAX in the above range can be said to have high transmittance for desired light in the near infrared region, and can be more suitably used in DBPF.

For light having a wavelength of 700 to 1000 nm incident on the surface of the substrate at an angle of incidence of 0°, the shortest wavelength (Tb_50%) at which the transmittance is 50% is preferably 780 to 980 nm, and more preferably 800 to 960 nm.
The present substrate having Tb_50% in the above range allows good transmission of a sensing light source having light emission characteristics in the near-infrared wavelength region, and therefore can be suitably used for DBPF.

The present substrate may have a conventionally known configuration except for having the near-infrared absorbing layer. Specific embodiments of the present substrate include the following substrates (I) to (III).
Substrate (I): Substrate having a glass substrate and the near-infrared absorbing layer Substrate (II): Substrate having a resin layer other than the near-infrared absorbing layer and the near-infrared absorbing layer Substrate (III): Substrate consisting of only the near-infrared absorbing layer

An example of the substrate (I) is a substrate 10 shown in FIG. 1A, in which a near-infrared absorbing layer 11 is formed on one surface of a glass substrate 12.
An example of the substrate (II) is a substrate 10 in which a near-infrared absorbing layer 11 is formed on one surface of a resin layer (resin substrate) 13 other than the near-infrared absorbing layer, as shown in FIG. 1B .
An example of the substrate (III) is a substrate 10 consisting of only a near-infrared absorbing layer 14 as shown in FIG. 1C.

The base material (I) may have, in addition to the glass substrate and the near-infrared absorbing layer, other layers such as an adhesion layer for improving adhesion therebetween, and a resin layer other than the near-infrared absorbing layer, such as an overcoat layer.
The base material (II) may have these other layers as a resin layer other than the near infrared absorbing layer.

The thickness of the substrate may be appropriately selected depending on the application of the substrate, but is preferably 0.08 to 0.6 mm, more preferably 0.09 to 0.4 mm, and even more preferably 0.10 to 0.35 mm.

<Near infrared absorbing layer>
The near infrared absorbing layer contains a resin and a near infrared absorbing compound, and is usually a layer in which the near infrared absorbing compound is uniformly dissolved or dispersed in the resin.
The near infrared absorbing layer contained in the substrate may be one layer or two or more layers. When the near infrared absorbing layer contained in the substrate is two or more layers, the substrate may have two or more similar near infrared absorbing layers or two or more different near infrared absorbing layers.

The thickness of the near infrared absorbing layer may be appropriately adjusted depending on the application of the substrate, the type and concentration of the dye used, etc., but is preferably 0.1 to 200 μm, more preferably 0.3 to 150 μm, and even more preferably 0.3 to 120 μm.
When a plurality of near-infrared absorbing layers are contained in the substrate, the thickness of the near-infrared absorbing layer refers to the thickness of each of the near-infrared absorbing layers.
If the thickness of the near-infrared absorbing layer is less than 0.1 μm, the desired optical properties may not be fully exhibited, whereas if the thickness of the near-infrared absorbing layer is more than 200 μm, the flatness of the layer may decrease, causing in-plane variations in absorptance.

[resin]
The resin is not particularly limited as long as it is a resin that can satisfy the above-mentioned dye retention rate, but from the viewpoint of easily obtaining a substrate having excellent durability that does not undergo thermal deterioration over a long period of time, it is preferable for the resin to contain at least one selected from the group consisting of polycarbonate and polysulfone, and from the viewpoint of easily obtaining a substrate having a dye retention rate in the above-mentioned range, it is more preferable for the resin to be polycarbonate and/or polysulfone.
The near infrared absorbing layer may contain one type of resin or two or more types of resins.

Polycarbonate is a polymer having a carbonate bond represented by -O-(C=O)-O- in a repeating unit. A representative example of the polycarbonate is a polymer synthesized by dehydrochlorination polycondensation of bisphenol A and phosgene, as shown in the following formula.

［式中、Ｚは、該Ｚが結合している炭素原子と共に、置換基を有していてもよい炭素数５～１５の環状炭化水素基を構成し、Ｒ^1aおよびＲ^1bは同一または異なり、炭素数１～２０のアルキル基、炭素数５～２０のシクロアルキル基、炭素数６～１０のアリール基、炭素数７～１４のアラルキル基、炭素数２～６のアルケニル基、炭素数１～１０のアルコキシ基、炭素数２～１０のアシル基、炭素数２～４のアルコキシカルボニル基、ハロゲン原子、ニトロ基またはシアノ基であり、ｍ１およびｍ２は同一または異なり、０～４の整数である。］ The polycarbonate preferably has a repeating unit represented by the following formula (1) from the viewpoint of easily obtaining a substrate having excellent durability that does not undergo thermal deterioration over a long period of time.

[In the formula, Z, together with the carbon atom to which Z is bonded, constitutes a cyclic hydrocarbon group having 5 to 15 carbon atoms which may have a substituent; R ^1a and R ^1b are the same or different and are an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 5 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 14 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an acyl group having 2 to 10 carbon atoms, an alkoxycarbonyl group having 2 to 4 carbon atoms, a halogen atom, a nitro group, or a cyano group; and m1 and m2 are the same or different and are an integer of 0 to 4.]

It is preferable that Z, together with the carbon atom to which Z is bonded, constitutes an aromatic hydrocarbon group or a cycloalkylidene group, which may have a substituent.
Preferred examples of the group formed by Z together with the carbon atom to which Z is bonded include a fluorene group and a cyclohexylidene group.
Examples of the substituent in Z include a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 5 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 14 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an acyl group having 2 to 10 carbon atoms, an alkoxycarbonyl group having 2 to 4 carbon atoms, a halogen atom, a nitro group, or a cyano group.

Examples of the alkyl group having a prime number of 1 to 20 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, an isobutyl group, and a t-butyl group.
Examples of the cycloalkyl group having 5 to 20 carbon atoms include a cyclopentyl group and a cyclohexyl group.
Examples of the aryl group having 6 to 10 carbon atoms include a phenyl group and an alkylphenyl group (eg, a methylphenyl group (tolyl group), a dimethylphenyl group (xylyl group)).
Examples of the aralkyl group having 7 to 14 carbon atoms include a benzyl group and a phenethyl group.
Examples of the alkenyl group having 2 to 6 carbon atoms include a vinyl group and a propenyl group.
The alkoxy group having 1 to 10 carbon atoms includes, for example, a methoxy group.
The acyl group having 2 to 10 carbon atoms includes, for example, an acetyl group.
The alkoxycarbonyl group having 2 to 4 carbon atoms includes, for example, a methoxycarbonyl group.

The above m1 and m2 are preferably 0 to 3, more preferably 0 to 2. Note that m1 and m2 may be different, but are usually the same.

Suitable examples of the repeating unit represented by formula (1) include a structural unit in which Z, together with the carbon atom to which Z is bonded, forms a cyclohexylidene group, and m1 and m2 are 0 , and a structural unit in which Z, together with the carbon atom to which Z is bonded, forms a fluorene group, and m1 and m2 are 0 .

As the repeating unit represented by formula (1), a repeating unit represented by the following formula (4) or (5) is preferred, and the repeating unit represented by the following formula (4) is more preferred from the viewpoint of having a good balance between heat resistance and transparency.

The polycarbonate preferably contains 50 mol % or more of the repeating unit represented by formula (1), more preferably 75 mol % or more, and even more preferably 100 mol %, of the total repeating units constituting the polycarbonate (100 mol %), in order to easily obtain a substrate having excellent durability without thermal degradation.

The viscosity average molecular weight of the polycarbonate is, for example, 5,000 to 100,000, preferably 8,000 to 50,000, and more preferably 10,000 to 30,000.
If the viscosity average molecular weight is too small (e.g., less than 5,000), the heat resistance of the polycarbonate may be reduced.Also, if the viscosity average molecular weight is too large (e.g., more than 100,000), not only is it difficult to synthesize the polycarbonate, but it may also be difficult to melt-knead when producing the substrate by melt-kneading, and the solubility in solvent may be reduced when forming a near-infrared absorbing layer by casting or coating.
Specifically, the viscosity average molecular weight can be measured by the method described in the examples below.

The glass transition point (Tg) of the polycarbonate is, for example, 110 to 250° C., preferably 120 to 240° C. If the Tg is too low (for example, lower than 110° C.), the heat resistance of the present substrate may decrease, and if the Tg is too high (for example, higher than 250° C.), melt-kneading may be difficult when forming the present substrate by melt-kneading.
Specifically, the Tg can be measured by the method described in the examples below.

The polycarbonate to be used may be one obtained by synthesis using a conventionally known method, or a commercially available product.
As a conventionally known method, for example, in a reaction using phosgene as a carbonate-forming compound, a method can be mentioned in which a dihydroxy compound is reacted with phosgene in the presence of an alkali compound such as sodium hydroxide, potassium hydroxide, etc., and a solvent such as methylene chloride, chlorobenzene, etc. In this case, a catalyst such as a tertiary amine such as triethylamine, a quaternary ammonium salt such as tetra-n-butylammonium bromide, or a phosphonium salt such as tetra-n-butylphosphonium bromide may be used to promote the reaction.

Polysulfone The polysulfone is a polymer having a sulfonyl bond represented by _-SO2- in the repeating unit. A representative example is a polymer having a repeating unit represented by the following formula, which is synthesized by desalting polycondensation of 4,4'-dichlorodiphenyl sulfone and the sodium salt of bisphenol A.

The polysulfone may be one obtained by synthesis using a conventional method, or a commercially available product may be used.

[Near infrared absorbing compound]
[0081] The near infrared absorbing compound is not particularly limited as long as it can satisfy the dye maintenance ratio and absorb near infrared ray (for example, a compound that has absorption or an absorption region in a wavelength region of about 700 to 1100 nm in an absorption spectrum of a solution dissolved in methylene chloride), and any conventionally known near infrared absorbing compound can be used.
The near infrared absorbing compound is usually dispersed or dissolved in the resin.
The near infrared absorbing layer may contain one kind of near infrared absorbing compound or two or more kinds of near infrared absorbing compounds.

The near infrared absorbing compound is preferably a compound soluble in an organic solvent, and particularly preferably a compound soluble in dichloromethane.
Here, being soluble in an organic solvent refers to the case where 0.1 g or more of the near infrared absorbing compound is dissolved in 100 g of an organic solvent at 25° C.

The content of the near-infrared absorbing compound in the near-infrared absorbing layer is desirably such that the absorbance at the maximum absorption wavelength λa of a resin film (comprising a resin, a near-infrared absorbing compound, and 0.3 parts by mass of Irganox 1010 (manufactured by BASF Japan Ltd.) per 100 parts by mass of the resin film) having a thickness of 90 to 110 μm obtained using the near-infrared absorbing compound is preferably within a range of 0.1 to 4.0, more preferably 0.2 to 3.0.

When the present substrate is, for example, the substrate (III), the content of the near infrared absorbing compound is preferably 0.005 to 3.0 parts by mass, more preferably 0.01 to 2.5 parts by mass, and particularly preferably 0.02 to 2.0 parts by mass, relative to 100 parts by mass of the resin in the near infrared absorbing layer.
When the present substrate is, for example, substrate (I) or (II), the content of the near infrared absorbing compound is preferably 0.5 to 45.0 parts by mass, more preferably 0.8 to 43.0 parts by mass, and particularly preferably 1.0 to 42.0 parts by mass, relative to 100 parts by mass of the resin in the near infrared absorbing layer.
When the content of the near infrared absorbing compound is within the above range, good near infrared absorbing properties can be achieved.

[0043] It is preferable that the near infrared absorbing compound includes at least one compound selected from the group consisting of a squarylium-based compound, a phthalocyanine-based compound, a dithiol-based compound, a diimonium-based compound, and a polymethine-based compound (the polymethine-based compound is a compound other than a squarylium-based compound) from the viewpoint that a base material having a high visible transmittance, a maximum absorption wavelength in the near infrared region, and a dye retention rate in the above range can be easily obtained.

The near-infrared absorbing compound preferably contains a polymethine compound, from the viewpoints that it is possible to easily reduce the shoulder peak in the red to near-infrared region based on the near-infrared absorbing compound, to sharply block the near-infrared region that is desired to be blocked, and to easily obtain a substrate having excellent light selective transparency, such as exhibiting high transmittance in the wavelength region that is desired to be transmitted (for example, the visible light region), and more preferably contains a polymethine compound and at least one compound selected from the group consisting of a squarylium compound, a phthalocyanine compound, a dithiol compound, and a diimonium compound, and even more preferably contains a polymethine compound, a squarylium compound, and at least one compound selected from the group consisting of a phthalocyanine compound, a dithiol compound, and a diimonium compound.

In addition, the near-infrared absorbing compound can easily reduce a shoulder peak in the red to near-infrared region based on the near-infrared absorbing compound, can sharply block the near-infrared region that is desired to be blocked, and can easily obtain a base material having excellent light selective transmittance, such as showing high transmittance in a wavelength region that is desired to be transmitted (for example, a visible light region).
A polymethine compound,
It is preferable that the near infrared absorbing compound includes a near infrared absorbing compound having a maximum absorption wavelength λmax in a wavelength region of 680 to 1000 nm in an absorption spectrum measured in a wavelength range of 300 to 1000 nm using a solution of the near infrared absorbing compound dissolved in dichloromethane (however, the near infrared absorbing compound is a compound other than a polymethine compound).
The λmax is preferably in the wavelength region of 700 to 980 nm, more preferably in the wavelength region of 710 to 960 nm. When a compound other than a polymethine compound having such a maximum absorption wavelength λmax is used, the decrease in visible light transmittance can be further suppressed while sufficiently cutting light of wavelengths in the near infrared region that is to be cut, and therefore the compound can be more suitably used in NIR-CFs and DBPFs.

Polymethine Compound In an absorption spectrum measured in a wavelength range of 300 to 1000 nm using a solution of the polymethine compound dissolved in dichloromethane, the polymethine compound preferably has a maximum absorption wavelength λmax in the wavelength range of 680 to 1000 nm, more preferably has a maximum absorption wavelength λmax in the wavelength range of 700 to 980 nm, and further preferably has a maximum absorption wavelength λmax in the wavelength range of 710 to 960 nm.
The use of a polymethine compound having such a maximum absorption wavelength λmax can more effectively suppress the decrease in visible light transmittance while sufficiently cutting off light having wavelengths in the near-infrared region that are to be cut off, and therefore the compound can be more suitably used in NIR-CFs and DBPFs.

The polymethine compound is preferably a polymethine compound represented by the following formula (2-1) or (2-2):

In formula (2-1), ^R5 to ^R8 , _Y1a to _Y1c , _Z1a and _Z1b each independently represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 6 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 14 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an acyl group having 2 to 10 carbon atoms, an alkoxycarbonyl group having 2 to 4 carbon atoms, a hydroxyl group, an amino group, an alkylamino group, an acylamino group (at least a part of the acyl group may be substituted with a halogen atom), a sulfonyl group, an alkylsulfonyl group, a halogenated alkyl group, a halogen atom, a nitro group or a cyano group. _Z1a and _Z1b may be bonded to each other to form a ring, and adjacent two of _Y1a , _Y1b and _Y1c may be bonded to each other to form a ring.
A ⁻ is a monovalent anion.

In formula (2-2), R ¹¹ to R ¹⁶ , Y _2a to Y _2c , Z _2a and Z _2b are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 6 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 14 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an acyl group having 2 to 10 carbon atoms, an alkoxycarbonyl group having 2 to 4 carbon atoms, a hydroxyl group, an amino group, an alkylamino group, an acylamino group (at least a part of the acyl group may be substituted with a halogen atom), a sulfonyl group, an alkylsulfonyl group, a halogenated alkyl group, a halogen atom, a nitro group or a cyano group. Z _1a and Z _1b may be bonded to each other to form a ring, and adjacent two of Y _1a , Y _1b and Y _1c may be bonded to each other to form a ring.
A ⁻ is a monovalent anion.

The above R ⁵ to R ⁸ , R ¹¹ to R ¹⁶ , Y _1a to Y _1c , Z _1a , Z _1b , Y _2a to Y _2c , Z _2a and Z _2b are each independently preferably a hydrogen atom, a chlorine atom, a fluorine atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a cyclohexyl group, an adamantyl group, a phenyl group, a hydroxyl group, an amino group, a dimethylamino group, a cyano group, a nitro group, an acetylamino group, a propionylamino group, an N-methylacetylamino group, a trifluoromethanoylamino group, a pentafluoroethanoylamino group, a tert-butanoylamino group, a cyclohex ... and more preferably a hydrogen atom, a chlorine atom, a fluorine atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an adamantyl group, a cyclohexyl group, a phenyl group, an amino group, a benzyl group, a diphenylmethyl group, a trifluoromethyl group, a difluoromethyl group, or a methoxy group.

The A ⁻ is not particularly limited as long as it is a monovalent anion, but preferable examples thereof include a chloride ion, a bromide ion, PF ₄ ⁻ , a perchlorate anion, a tristrifluoromethanesulfonylmethide anion, a tetrafluoroborate anion, a hexafluorophosphate anion, a bis(trifluoromethanesulfonyl)imide anion, a trifluoromethanesulfonate anion, a tetrakis(pentafluorophenyl)borate anion, a tetrakis(pentafluorophenyl)gallate anion, and a tetrakis(3,5-bis(trifluoromethyl)phenyl)borate anion, and more preferable examples thereof include a bis(trifluoromethanesulfonyl)imide anion, a trifluoromethanesulfonate anion, a tristrifluoromethanesulfonylmethide anion, a tetrakis(pentafluorophenyl)gallate anion, and a tetrakis(3,5-bis(trifluoromethyl)phenyl)borate anion. [0043] In view of obtaining a compound having superior heat resistance, more preferred are the bis(trifluoromethanesulfonyl)imide anion, tristrifluoromethanesulfonylmethide anion, tetrakis(pentafluorophenyl)borate anion, tetrakis(pentafluorophenyl)gallate anion, and tetrakis(3,5-bis(trifluoromethyl)phenyl)borate anion, and particularly preferred is the tetrakis(pentafluorophenyl)borate anion.

Suitable examples of the polymethine compounds represented by the formulas (2-1) and (2-2) include the compounds represented by the following formulas (2a) to (2h).

In the case where the present substrate is, for example, the substrate (III) and the near-infrared absorbing layer contains a polymethine compound, the content of the polymethine compound in the near-infrared absorbing layer, in particular the content of the compounds represented by the formulas (2-1) and (2-2), is preferably 0.005 to 2.0 parts by mass, more preferably 0.01 to 1.5 parts by mass, and particularly preferably 0.02 to 1.0 part by mass, relative to 100 parts by mass of the resin in the near-infrared absorbing layer.
When the present substrate is, for example, the substrate (I) or (II) and the near-infrared absorbing layer contains a polymethine compound, the content of the polymethine compound in the near-infrared absorbing layer, in particular the content of the compounds represented by the formulas (2-1) and (2-2), is preferably 0.5 to 45.0 parts by mass, more preferably 0.8 to 43.0 parts by mass, and particularly preferably 1.0 to 42.0 parts by mass, relative to 100 parts by mass of the resin in the near-infrared absorbing layer.
When the content of the polymethine compound in the near infrared absorbing layer, particularly the compound represented by the formulae (2-1) and (2-2), is within the above range, near infrared rays having a wavelength of 700 to 740 nm can be efficiently cut and a base material having excellent visible light transmittance can be easily obtained.

Squarylium Compound The squarylium compound is preferably a squarylium compound represented by the following formula (1).
The squarylium compound represented by the formula (1) has good solubility in organic solvents and good compatibility with resins, so that even if the thickness of the near-infrared absorbing layer is reduced, the near-infrared absorbing layer has excellent spectral characteristics, and an optical filter using the near-infrared absorbing layer can be made small and thin.

In formula (1), X is independently a single bond or an oxygen atom, Y is independently an alkanediyl group having 1 to 12 carbon atoms in which one or more hydrogen atoms may be substituted with an alkyl group or an alkoxy group having 1 to 12 carbon atoms, and Z is independently a sulfonyl group or a carbonyl group.

In formula (1), R ¹ independently represents a saturated or unsaturated hydrocarbon group having 1 to 12 carbon atoms, a saturated cyclic hydrocarbon group having 3 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an araryl group having 7 to 13 carbon atoms, which may contain a saturated ring structure or may be branched.

In formula (1), ^R2 is independently a group having 1 to 25 carbon atoms in which one or more hydrogen atoms may be substituted with a halogen atom, a hydroxyl group, a carboxy group, a sulfo group, or a cyano group, and which may contain an unsaturated bond, an oxygen atom, or a saturated or unsaturated ring structure between the carbon atoms.
In addition, two R ^{2 s} in formula (1) may be bonded to each other to form a ring structure.

In formula (1), R ³ and R ⁴ are independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms.

The squarylium compound represented by the formula (1) has a squarylium skeleton in the center of the molecular structure, with one benzene ring bonded to each side of the squarylium skeleton, and the benzene ring is bonded to a nitrogen atom at the 4th position, forming a fused ring structure in which a heterocycle containing the nitrogen atom and the carbon atoms at the 4th and 5th positions of the benzene ring is formed.

When a urethane group is bonded to the second position of the benzene rings bonded to the left and right of the squarylium skeleton, the compound has spectral transmittance characteristics in the near infrared and visible regions that are equal to or greater than those of conventional squarylium compounds, and the near infrared absorbing layer containing the compound is preferred because it tends to have high adhesion, particularly to layers made of inorganic materials such as glass and dielectric multilayer films.

From the viewpoint of solubility in organic solvents and compatibility with resins, the substituent R ¹ in formula (1) is preferably a group having a branched structure, and more preferably an alkyl or alkoxy group having a branched structure.
In addition, when a compound in which the substituent R ¹ in formula (1) is a fluorinated alkyl group having a fluorine atom (e.g., a trifluoromethyl group, a pentafluoroethyl group) is used, the dispersibility in a resin such as a polycarbonate or a polysulfone is improved, and the heat resistance of the near infrared absorbing layer containing the compound is improved.

It is particularly preferable that Y in formula (1) is any one of the divalent organic groups represented by the following formulae (1-1) to (1-6), where the left side of each of the following formulae (1-1) to (1-6) is a divalent group bonded to a benzene ring and the right side is bonded to N.
-C(CH ₃ ) ₂ -CH(CH ₃ )- (1-1)
-C(CH ₃ ) ₂ -CH ₂ - (1-2)
-C(CH ₃ ) ₂ -CH(C ₂ H ₅ )- (1-3)
-C(CH ₃ ) ₂ -CH ₂ -CH ₂ - (1-4)
-C(CH ₃ ) ₂ -CH ₂ -CH(CH ₃ )- (1-5)
-C(CH ₃ ) ₂ -CH(CH ₃ )-CH ₂ - (1-6)

Among these, Y in formula (1) is preferably any of the groups shown in formulas (1-1) to (1-3), and more preferably the group shown in formula (1-1).

Suitable examples of squarylium compounds represented by formula (1) include the following formulas (1a) to (1c):

[0043] In the case where the present substrate is, for example, the substrate (III) and the near-infrared absorbing layer contains a squarylium-based compound, the content of the squarylium-based compound in the near-infrared absorbing layer, in particular the content of the compound represented by the formula (1), is preferably more than 0 part by mass and is preferably 0.4 parts by mass or less, more preferably 0.3 parts by mass or less, and particularly preferably 0.2 parts by mass or less, relative to 100 parts by mass of the resin in the near-infrared absorbing layer.
[0043] In the case where the present substrate is, for example, the substrate (I) or (II) and the near-infrared absorbing layer contains a squarylium-based compound, the content of the squarylium-based compound in the near-infrared absorbing layer, in particular the content of the compound represented by formula (1), is preferably more than 0 part by mass and is preferably 12.0 parts by mass or less, more preferably 10.0 parts by mass or less, and particularly preferably 8 parts by mass or less, relative to 100 parts by mass of the resin in the near-infrared absorbing layer.
When the content of the squarylium-based compound, particularly the compound represented by the formula (1), in the near-infrared absorbing layer is within the above range, the decrease in visible light transmittance can be further suppressed while sufficiently cutting off light having a wavelength in the near-infrared region that is to be cut off, and therefore the near-infrared absorbing layer can be more suitably used in NIR-CFs and DBPFs.

Phthalocyanine Compounds Specific examples of the phthalocyanine compounds that can be used include a compound having a structure represented by the following formula (F) and commercially available products such as EX Color 810K (manufactured by Nippon Shokubai Co., Ltd.).

Dithiol Compounds As dithiol compounds, for example, nickel-bis-1,2-diphenyl-1,2-ethenedithiolate (MIR101, manufactured by Midori Chemical Co., Ltd.) can be used.

Diimonium Compounds As the diimonium compound, for example, IRG022 (manufactured by Nippon Kayaku Co., Ltd.) can be used.

[Other ingredients]
[0113] In addition to the resin and the near infrared absorbing compound, the near infrared absorbing layer may appropriately contain other components, such as an ultraviolet absorbing compound, an antioxidant, a heat stabilizer, a flame retardant, a release agent, an antistatic agent, an antibacterial agent, a lubricant, and a filler, as necessary, within a range that does not impair the effects of the present invention.
The other components may each be used alone or in combination of two or more.

Ultraviolet absorbing compound Examples of the ultraviolet absorbing compound include azomethine compounds, indole compounds, benzotriazole compounds, triazine compounds, anthracene compounds, cyanoacrylate compounds, and compounds described in JP-A-2019-014707, etc. Among these, azomethine compounds, indole compounds, benzotriazole compounds, and cyanoacrylate compounds are particularly preferred from the viewpoint of absorption wavelength and compound stability.
By containing an ultraviolet absorbing compound, an optical filter that has little incidence angle dependency even in the near-ultraviolet wavelength region can be easily obtained, and when this filter is used in an imaging device or the like, the obtained camera image quality is better.

For the same reasons as above, the ultraviolet absorbing compound is preferably a compound having a maximum absorption wavelength λmax in the wavelength region of 350 to 420 nm, and more preferably a compound having a maximum absorption wavelength λmax in the wavelength region of 370 to 410 nm.
By using an ultraviolet absorbing compound having such an absorption maximum wavelength λmax, an optical filter having little incidence angle dependency even in the near-ultraviolet wavelength region can be easily obtained, and when this filter is used in an imaging device or the like, the obtained camera image quality becomes better.
The maximum absorption wavelength λmax can be measured using a solution in which the ultraviolet absorbing compound is dissolved in dichloromethane.

In the case where the present substrate is, for example, the substrate (III) and the near-infrared absorbing layer contains an ultraviolet absorbing compound, the content of the ultraviolet absorbing compound in the near-infrared absorbing layer is preferably 0.005 to 0.8 parts by mass, more preferably 0.01 to 0.6 parts by mass, and particularly preferably 0.02 to 0.5 parts by mass, relative to 100 parts by mass of the resin in the near-infrared absorbing layer.
In the case where the present substrate is, for example, the substrate (I) or (II) and the near-infrared absorbing layer contains an ultraviolet absorbing compound, the content of the ultraviolet absorbing compound in the near-infrared absorbing layer is preferably 0.01 to 30.0 parts by mass, more preferably 0.05 to 25.0 parts by mass, and particularly preferably 0.1 to 20.0 parts by mass, relative to 100 parts by mass of the resin in the near-infrared absorbing layer.
When the content of the ultraviolet absorbing compound in the near-infrared absorbing layer is within the above range, the decrease in visible light transmittance can be further suppressed while sufficiently cutting off light with wavelengths in the ultraviolet region that is to be cut, and therefore the near-infrared absorbing layer can be more suitably used for NIR-CF and DBPF.

Antioxidant As the antioxidant, a conventionally known antioxidant can be used. Specific examples of the antioxidant include phenol-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants. Among these, phenol-based antioxidants, in particular alkyl-substituted phenol-based antioxidants, are preferred.

Specific examples of the antioxidant include triethylene glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 1,3,5-trimethyl-2,4,6-tris(3,5-di -tert-butyl-4-hydroxybenzyl)benzene, N,N-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyhydrocinnamide), 3,5-di-tert-butyl-4-hydroxybenzylphosphonate diethyl ester, tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, 3,9-bis{1,1-dimethyl-2-[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl}-2,4,8,10-tetraoxaspiro[5.5]undecane, etc.

When the near-infrared absorbing layer contains an antioxidant, the content of the antioxidant in the near-infrared absorbing layer is preferably 0.0001 to 0.05% by mass relative to 100% by mass of the near-infrared absorbing layer.

The heat stabilizer is preferably a phosphorus-based stabilizer, such as a phosphite compound, a phosphate compound, or a phosphonite compound.

Examples of the phosphite compound include triphenyl phosphite, trisnonylphenyl phosphite, tris(2,4-di-tert-butylphenyl)phosphite, tridecyl phosphite, trioctyl phosphite, trioctadecyl phosphite, didecyl monophenyl phosphite, dioctyl monophenyl phosphite, diisopropyl monophenyl phosphite, monobutyl diphenyl phosphite, monodecyl diphenyl phosphite, monooctyl diphenyl phosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,2-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite, bis(nonylphenyl)pentaerythritol diphosphite, and bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite.

Examples of the phosphate compounds include tributyl phosphate, trimethyl phosphate, tricresyl phosphate, triphenyl phosphate, trichlorophenyl phosphate, triethyl phosphate, diphenyl cresyl phosphate, diphenyl monoorthoxenyl phosphate, tributoxyethyl phosphate, dibutyl phosphate, dioctyl phosphate, and diisopropyl phosphate.

Examples of the phosphonite compound include tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite, tetrakis(2,4-di-tert-butylphenyl)-4,3'-biphenylene diphosphonite, tetrakis(2,4-di-tert-butylphenyl)-3,3'-biphenylene diphosphonite, and bis(2,4-di-tert-butylphenyl)-4-biphenylene diphosphonite.

Among these, tris(2,4-di-tert-butylphenyl)phosphite, triphenyl phosphate, and trimethyl phosphate are preferred as the heat stabilizer.

When the near-infrared absorbing layer contains a heat stabilizer, the content of the heat stabilizer in the near-infrared absorbing layer is preferably 0.001 to 0.5 parts by mass, more preferably 0.005 to 0.3 parts by mass, per 100 parts by mass of the resin in the near-infrared absorbing layer.

<Glass substrate>
The glass substrate contained in the base material (I) is not particularly limited, but examples thereof include substrates made of fluorophosphate glass, near-infrared absorbing glass (e.g., absorbing glass in which CuO or the like is added to phosphate glass), soda-lime glass, borosilicate glass, alkali-free glass, quartz glass, sapphire glass, etc. The "phosphate glass" also includes silicophosphate glass in which part of the glass skeleton is composed of _SiO2 .

The glass substrate contained in the substrate (I) may be one layer or two or more layers. When the glass substrate contained in the substrate (I) is two or more layers, the substrate (I) may have two or more layers of the same glass substrate, or may have two or more layers of different glass substrates.

The thickness of the glass substrate may be appropriately selected depending on the application of the substrate, but is preferably 0.04 to 0.5 mm, more preferably 0.05 to 0.3 mm, and even more preferably 0.06 to 0.25 mm.

<Resin Layer Other Than Near-Infrared Absorption Layer>
The resin layer other than the near infrared absorbing layer contained in the base material (II) and the resin layer other than the near infrared absorbing layer that can be contained in the base material (I) refer to a resin layer that does not contain a near infrared absorbing compound.
The resin layer other than the near infrared absorbing layer contained in the present substrate may be one layer or two or more layers. When the resin layer other than the near infrared absorbing layer contained in the present substrate is two or more layers, the present substrate may have two or more similar resin layers or two or more different resin layers.

The resin layer other than the near-infrared absorbing layer may contain a resin, and the resin is preferably the same as the resin described in the section on the near-infrared absorbing layer.
Resins such as polyester, polyarylate, polyimide, polycycloolefin, and epoxy resin may also be used by adjusting the conditions of use, although they may have poor heat resistance. Commercially available resins such as OGSOL EA-F5003 (manufactured by Osaka Gas Chemicals Co., Ltd.), polymethyl methacrylate, polyisobutyl methacrylate (all manufactured by Tokyo Chemical Industry Co., Ltd.), BR50 (manufactured by Mitsubishi Chemical Corporation), ARTON (manufactured by JSR Corporation), Zeonex, and Zeonor (manufactured by Zeon Corporation) may also be used.

The resin layer other than the near-infrared absorbing layer may be a so-called resin substrate or overcoat layer, or may be a functional layer such as an adhesion layer, an anti-reflection layer, a hard coat layer, or an antistatic layer for improving the adhesion between the resin substrate or overcoat layer and the near-infrared absorbing layer, between the glass substrate and the near-infrared absorbing layer, or between the substrate and the dielectric multilayer film described below.

The thickness of the resin layer other than the near-infrared absorbing layer may be appropriately selected depending on the purpose of using the resin layer, but is preferably 0.1 to 20 μm, more preferably 0.5 to 10 μm, and even more preferably 0.7 to 5 μm.

<Method of manufacturing substrate>
The near infrared absorbing layer and the base material (III) can be formed, for example, by a casting method using a composition for forming a near infrared absorbing layer containing the resin and a near infrared absorbing compound, or by melt molding (e.g., injection molding, melt extrusion molding, blow molding) using a composition for forming a near infrared absorbing layer that is a blend of the resin and the near infrared absorbing compound. In a normal melt molding method, the film is formed at high temperature (e.g., 200°C or higher), so there is a risk of the near infrared absorbing compound being thermally decomposed, whereas in the casting method, the film can be formed at a relatively low temperature (e.g., 150°C or lower), so that the thermal decomposition of the near infrared absorbing compound can be suppressed or prevented, and even a near infrared absorbing compound with low heat resistance can be used if it can be dissolved or uniformly dispersed in a solvent, so among these, the casting method is preferred.

The near infrared absorbing layer forming composition may contain one or more solvents. The solvent may be selected in consideration of the solubility of the resin and the near infrared absorbing compound, inertness to the near infrared absorbing compound, boiling point, etc.
Examples of the solvent include halogenated organic solvents (e.g., aliphatic halogen compounds such as chloroform, dichloromethane, and dichloroethane, and aromatic halogen compounds such as chlorobenzene), non-halogenated organic solvents (e.g., aromatic hydrocarbons such as toluene, xylene, and mesitylene, ketones such as methyl ethyl ketone, acetone, cyclohexanone, and cyclopentanone, ethers such as tetrahydrofuran, and esters such as propylene glycol monomethyl ether acetate).

The near-infrared absorbing layer forming composition may further contain one or more known surfactants. By incorporating a surfactant, it is possible to improve the appearance, particularly voids caused by minute bubbles, depressions caused by the adhesion of foreign matter, and repellency during the drying process.

The concentration of solids in the near-infrared absorbing layer forming composition used in the casting method may be adjusted depending on the type of solvent, the film thickness of the substrate to be prepared, the preparation method, etc., and is, for example, 1 to 30% by mass, preferably 5 to 25% by mass. If the concentration of solids is too low, coating unevenness is likely to occur, and if it is too high, the coating appearance is likely to be poor.

The cast molding may be a method of forming a near-infrared absorbing layer by casting a composition for forming a near-infrared absorbing layer onto a support such as a glass substrate, a resin layer other than the near-infrared absorbing layer, a steel belt, or a steel drum.
By peeling off the support from the near-infrared absorbing layer thus formed, the substrate (III) can be obtained. A near-infrared absorbing layer with a support in which a glass substrate is used as the support can be the substrate (I). A near-infrared absorbing layer with a support in which a resin layer other than the near-infrared absorbing layer is used as the support can be the substrate (II).

The casting method is not particularly limited, and any conventionally known method can be used, including, for example, immersion, spraying, spin coating, wire bar coating, blade coating, roll coating, curtain coating, slit die coating, gravure coating, slit reverse coating, microgravure, inkjet, and comma coating.

The method for forming the near-infrared absorbing layer may include, for example, a method of removing the solvent from the composition for forming the near-infrared absorbing layer by heating as necessary. In addition, depending on the resin used, a method of curing the composition for forming the near-infrared absorbing layer by an appropriate method such as ultraviolet irradiation or heating may also be used.

The above-mentioned substrate (I) or (II) can be formed with a near-infrared absorbing layer by casting a composition for forming a near-infrared absorbing layer on the above-mentioned glass substrate or a resin layer other than the near-infrared absorbing layer, and in this case, the casting method can also be said to be a coating method. The substrate (I) or (II) thus produced may be further coated with a coating agent such as an overcoat layer, an antireflection agent, a hard coat agent and/or an antistatic agent after molding, if necessary.
The base material (II) can also be produced, for example, by co-extruding a near-infrared absorbing layer-forming composition and a resin layer-forming component other than the near-infrared absorbing layer.

When the base material (I) or (II) is produced by forming a near-infrared absorbing layer on the glass substrate or a resin layer other than the near-infrared absorbing layer by a casting method using a composition for forming a near-infrared absorbing layer, the glass substrate or the resin layer other than the near-infrared absorbing layer may be pretreated in advance before casting the composition for forming a near-infrared absorbing layer.
As the pretreatment, a conventionally known method can be used, for example, a method using one or more pretreatment agents such as a silane coupling agent.

Optical Filter
An optical filter according to one embodiment of the present invention (hereinafter also referred to as "the present filter") has a dielectric multilayer film on at least one surface of the present substrate.

The filter may have two or more dielectric multilayer films. In this case, two or more dielectric multilayer films may be on one side of the substrate, but it is preferable that the substrate has one or more dielectric multilayer films on each side. In this case, each dielectric multilayer film is counted as one. When the filter has two or more dielectric multilayer films, the filter may have two or more similar multilayer films, or may have two or more different multilayer films.

As the present filter having such a dielectric multilayer film, a filter having a dielectric multilayer film on one of the main surfaces of the present substrate, or a filter having a dielectric multilayer film on both of the main surfaces of the present substrate, is preferred.
When the dielectric multilayer film is provided on one side, an optical filter having excellent manufacturing cost and ease of manufacture can be easily obtained, and when the dielectric multilayer film is provided on both sides, an optical filter having high strength and being resistant to warping and twisting can be easily obtained. When the dielectric multilayer film is provided on one side, the substrate is preferably the substrate (I) because the substrate is resistant to warping and twisting.
When the present filter is used in an optical sensor device or the like, it is preferable that the filter has little warping or twisting, and therefore it is preferable to provide a dielectric multilayer film on both sides of the present substrate.

In the present filter, a functional film such as a support, an antireflection film, a hard coat film or an antistatic film may be appropriately provided between the present substrate and the dielectric multilayer film, on the surface of the present substrate opposite the surface on which the dielectric multilayer film is provided, or on the surface of the dielectric multilayer film opposite the surface on which the present substrate is provided, for the purposes of improving the surface hardness of the present substrate or the dielectric multilayer film, improving the chemical resistance, preventing static electricity and removing scratches, etc., within the scope of the present invention.
The present filter may include one layer of the functional membrane, or may include two or more layers. When the present filter includes two or more layers of the functional membrane, the functional membrane may include two or more layers of the same membrane, or may include two or more layers of different membranes.

Specific examples of this filter include near-infrared cut filters (NIR-CF), dual bandpass filters (DBPFs) such as visible light-near-infrared selective transmission filters, and single bandpass filters such as near-infrared transmission filters (IRPFs). This filter can also be used as a filter for alternative light sources (ALS: Alternative Light Sources) used in scientific investigations and the like, or as a filter for environmental light sensors. Among these, it is preferable that this filter is a DBPF, and in particular a visible light-near-infrared selective transmission filter, in order to better demonstrate the effects of the present invention.

The visible light/near infrared selective transmission filter is not particularly limited as long as it is an optical filter that transmits visible light and near infrared light of a wavelength that is desired to be transmitted and cuts near infrared light of a wavelength that is desired to be cut.
The dielectric multilayer film used in this visible light-near infrared light selective transmission filter is preferably a film that transmits visible light and near infrared light having a wavelength that is desired to be transmitted, and blocks near infrared light having a wavelength that is desired to be blocked.

It is desirable for the present filter to have a wavelength band in the 750 to 900 nm region in which the transmittance of light incident on the surface of the present filter at an angle of incidence of 0° is preferably 70% or less, more preferably 60% or less, and even more preferably 50% or less.
The present filter having this wavelength band is capable of reducing unnecessary near-infrared light, and therefore can be suitably used in a DBPF.

The present filter desirably has a first transmission wavelength band in the wavelength region of 400 to 700 nm, in which the transmittance of light incident on the surface of the present filter at an incident angle of 0° is preferably 40% or more, more preferably 50% or more, and even more preferably 60% or more.
It is desirable for the present filter to have a second transmission wavelength band in the wavelength region of 750 to 1000 nm, in which the transmittance of light incident on the surface of the present filter at an angle of incidence of 0° is preferably 40% or more, more preferably 50% or more, and even more preferably 60% or more.
In addition, the present filter desirably has a light blocking band (Xa) between the first transmission wavelength band and the second transmission wavelength band.
The present filter having such first and second transmission wavelength bands and light blocking band (Xa) can be suitably used in a DBPF.

The light blocking band (Xa) refers to the wavelength band from the shortest wavelength Xa1, where the transmittance of light incident on the surface of the optical filter at an angle of incidence of 0° is greater than 20% to less than 20%, to the longest wavelength Xa2, where the transmittance is less than 20% to more than 20%, in the wavelength range of 650 to 900 nm.

In the light blocking band (Xa), the minimum transmittance (the lowest transmittance in the wavelength band from Xa1 to Xa2) of light incident on the surface of the present filter at an incident angle of 0° is preferably 15% or less, more preferably 10% or less, even more preferably 8% or less, more preferably 6% or less, and particularly preferably 5% or less. The lower limit is not particularly limited and may be 0%.
When the present filter is used in a solid-state image sensor having a near-infrared sensing function, it is preferable that the minimum transmittance of the light blocking band Xa is low. In such a case, it is possible to effectively cut off light of unnecessary wavelengths, and it is possible to easily obtain a camera image with excellent color reproducibility while achieving high near-infrared sensing performance with little noise.

The average transmittance (Tf_AVE) of light having a wavelength of 430 to 580 nm incident on the surface of the present filter at an incident angle of 0° is preferably 70% or more, more preferably 75% or more. Since a higher average transmittance is preferable, the upper limit is not particularly limited and may be 100%.
The present filter having Tf_AVE in the above range can be said to have high visible light transmittance, and can further suppress the decrease in visible light transmittance while sufficiently cutting light of wavelengths in the near-infrared region that are to be cut, and therefore can be more suitably used in NIR-CFs and DBPFs.

The maximum transmittance (Tf_MAX) of light having a wavelength of 700 to 1000 nm incident on the surface of this filter at an incident angle of 0° is preferably 70% or more, more preferably 80% or more, and the upper limit is not particularly limited, but is, for example, 100%.
The present filter having Tf_MAX in the above range can be said to have high transmittance for desired light in the near infrared region, and can be suitably used as a DBPF.

The average transmittance (Tf_AVE750-900) of light having a wavelength of 750 to 900 nm incident on the surface of the filter at an incident angle of 0° is preferably 0 to 60%, more preferably 0 to 50%.
The present filter having Tf_AVE750-900 in the above range can be said to be capable of cutting desired light in the near infrared region, and can be suitably used as a DBPF.

The near-infrared sensing sensitivity of this filter, which is the difference between “Tf_MAX” and “Tf_AVE750-900” (“Tf_MAX” − “Tf_AVE750-900”), is preferably 40% or more, more preferably 42% or more, and the upper limit is not particularly limited, but is, for example, 100%.
This filter, whose near-infrared sensing sensitivity is within the above range, has a large difference in transmittance between the transmission band and the blocking band in the near-infrared region and can be said to have high near-infrared sensing sensitivity, and can be suitably used in optical sensor devices.

This filter is excellent in, for example, its ability to cut off light of wavelengths in the range that is to be cut off, and its ability to transmit light of wavelengths that are to be transmitted. Therefore, it is useful for correcting the visibility of solid-state imaging elements such as CCD and CMOS image sensors in camera modules, and for optical sensor devices. It is particularly useful for digital still cameras, smartphone cameras, mobile phone cameras, digital video cameras, cameras for wearable devices, PC cameras, surveillance cameras, automotive cameras, infrared cameras, televisions, car navigation systems, personal digital assistants, video game consoles, portable game consoles, fingerprint authentication systems, digital music players, various sensing systems, infrared communications, and the like. It is also useful as a heat-cutting filter to be attached to glass panels in automobiles, buildings, and the like.

<Dielectric multilayer film>
The dielectric multilayer film is, for example, a multilayer film made of different inorganic materials, and specifically functions as a selective wavelength blocking film that blocks light in a specific wavelength range, an anti-reflection film that suppresses transmittance loss in the visible range, etc.
Specific examples of the dielectric multilayer film include a laminate in which high refractive index material layers and low refractive index material layers are alternately laminated.

Materials constituting the high refractive index material layer include materials with a refractive index of 1.7 or more, and materials with a refractive index of 1.7 to 2.5 are usually selected. Examples of such materials include those that contain titanium oxide, zirconium oxide, tantalum pentoxide, niobium pentoxide, lanthanum oxide, yttrium oxide, zinc oxide, zinc sulfide, indium oxide, or the like as the main component, and contain small amounts of titanium oxide, tin oxide, and/or cerium oxide, or the like (for example, 0 to 10% by mass of the main component).

The low refractive index material layer may be made of a material with a refractive index of 1.6 or less, and a material with a refractive index of 1.2 to 1.6 is usually selected. Examples of such materials include silica, alumina, lanthanum fluoride, magnesium fluoride, and sodium aluminum hexafluoride.

There are no particular limitations on the method for laminating the high refractive index material layers and the low refractive index material layers, so long as a dielectric multilayer film is formed by laminating these material layers. For example, a dielectric multilayer film in which high refractive index material layers and low refractive index material layers are alternately laminated can be formed directly on the substrate by a CVD method, a sputtering method, a vacuum deposition method, an ion-assisted deposition method, an ion plating method, or the like.

The physical thickness of each of the high refractive index material layers and the low refractive index material layers varies depending on the refractive index of each layer, but is preferably 5 to 500 nm, and the total physical thickness of the dielectric multilayer film is preferably 1.0 to 8.0 μm for the entire filter.
The total number of high refractive index material layers and low refractive index material layers in the dielectric multilayer film is, in the present filter as a whole, preferably 16 to 70 layers, more preferably 20 to 60. When the thickness of each layer, the thickness of the dielectric multilayer film as the entire optical filter, and the total number of layers are within the above ranges, a sufficient manufacturing margin can be ensured, and warping of the present filter and cracks in the dielectric multilayer film can be reduced.

In this filter, by appropriately selecting the material types constituting the high and low refractive index material layers, the thickness of each of the high and low refractive index material layers, the order of lamination, and the number of layers, it is possible to obtain an optical filter that has a light blocking band and a light transmission band of the desired wavelength in the near-infrared wavelength range while ensuring sufficient transmittance in the visible range.

Here, to optimize the above conditions, for example, optical thin film design software (e.g., Essential Macleod, manufactured by Thin Film Center) can be used to set parameters so as to lower the transmittance in the wavelength range in the near-infrared wavelength range where it is desired to suppress the transmission of light rays, and to increase the transmittance in the wavelength range where it is desired to transmit light rays. For example, when a light transmission band is set around 800 nm by a dielectric multilayer film formed on both sides, the software is used to set the target transmittance of one dielectric multilayer film to 0% for light with a wavelength of 720 to 760 nm and 100% for light with a wavelength of 780 to 820 nm, and the target tolerance value for each wavelength range is set to 0.5 or less, and the target transmittance of the other dielectric multilayer film to 100% for light with a wavelength of 780 to 820 nm and 0% for light with a wavelength of 850 to 1100 nm, and the target tolerance value for each wavelength range is set to 0.5 or less.

<Other functional films>
The method for laminating the functional film is not particularly limited, but examples thereof include a method in which a coating agent such as an antireflection agent, a hard coat agent and/or an antistatic agent is applied to the substrate or the dielectric multilayer film in the same manner as described above by melt molding or cast molding.

It can also be produced by applying a curable composition containing the coating agent or the like to the substrate or the dielectric multilayer film using a bar coater or the like, and then curing it by exposure to ultraviolet light or the like.

Examples of the coating agent include ultraviolet (UV)/electron beam (EB) curable resins and thermosetting resins, and more specifically, examples thereof include vinyl compounds, urethane-based, urethane acrylate-based, acrylate-based, epoxy-based and epoxy acrylate-based resins. The coating agent may be used alone or in combination of two or more kinds.
Examples of the curable compositions containing these coating agents include vinyl-based, urethane-based, urethane acrylate-based, acrylate-based, epoxy-based and epoxy acrylate-based curable compositions.

The curable composition may contain a polymerization initiator. As the polymerization initiator, a known photopolymerization initiator or a thermal polymerization initiator may be used, and a photopolymerization initiator and a thermal polymerization initiator may be used in combination. The polymerization initiator may be used alone or in combination of two or more kinds.

The blending ratio of the polymerization initiator in the curable composition is preferably 0.1 to 10% by mass, more preferably 0.5 to 10% by mass, and even more preferably 1 to 5% by mass, when the total amount of the curable composition is taken as 100% by mass. When the blending ratio of the polymerization initiator is within the above range, a curable composition having excellent curing properties and ease of handling can be easily obtained, and a functional film such as an anti-reflective film, a hard coat film, or an antistatic film having the desired hardness can be easily obtained.

Further, an organic solvent may be added to the curable composition as a solvent, and a known solvent may be used as the organic solvent. Specific examples of the organic solvent include alcohols such as methanol, ethanol, isopropanol, butanol, and octanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; esters such as ethyl acetate, butyl acetate, ethyl lactate, γ-butyrolactone, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate; ethers such as ethylene glycol monomethyl ether and diethylene glycol monobutyl ether; aromatic hydrocarbons such as benzene, toluene, xylene, and mesitylene; and amides such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone.
These solvents may be used alone or in combination of two or more.

The thickness of the functional film is preferably 0.1 to 20 μm, more preferably 0.5 to 10 μm, and particularly preferably 0.7 to 5 μm.

In addition, in order to improve the adhesion between the substrate and the functional film and/or the dielectric multilayer film, or between the functional film and the dielectric multilayer film, the surfaces of the substrate, the functional film, or the dielectric multilayer film may be subjected to a surface treatment such as a corona treatment or a plasma treatment.

<Optical sensor device>
The optical sensor device according to one embodiment of the present invention is not particularly limited as long as it includes the present filter, and may have a conventionally known configuration. The optical sensor device is preferably an ambient light sensor device.
The optical sensor device may be, for example, a device having a light receiving element and the present filter, and specifically, may be a device having a light receiving element (semiconductor substrate), a protective film, the present filter, another filter, and the like.
Here, an optical sensor is a sensor that can detect the surrounding brightness and color tone (e.g., strong red in the evening). For example, the information detected by the optical sensor can be used to control the illuminance and color tone of the display installed in the device.

The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.

<Molecular weight>
The viscosity average molecular weight of the resins obtained in Synthesis Examples 1 and 2 was measured as follows.
The resins obtained in Synthesis Examples 1 and 2 were dissolved in methylene chloride at 20° C. to a concentration of 0.7 g/dl to prepare solutions, which were then used to measure the specific viscosity (η _SP ) and calculate the intrinsic viscosity ([η]) from the following formula, and then calculate the viscosity average molecular weight (M) from the following formula, where C represents the resin concentration in the solution used.
η _sp /C=[η]+0.45×[η] ² ×C
[η]=1.23× ^10-4 ×M ^0.83

The molecular weight of the resin D obtained in Synthesis Example 3 was measured as follows.
The weight average molecular weight (Mw) and number average molecular weight (Mn) in terms of standard polystyrene were measured using a GPC apparatus manufactured by Tosoh Corporation (HLC-8220 type, column: TSKgel α-M, developing solvent: THF).

<Glass transition temperature (Tg)>
The glass transition temperature (Tg) of the resin used in the following examples was measured using a differential scanning calorimeter (DSC6200) manufactured by Hitachi High-Tech Science Corporation at a temperature rise rate of 20° C. per minute in a nitrogen stream.

[Synthesis Example 1]
In a reactor equipped with a thermometer, a stirrer and a reflux condenser, 14863 parts by mass of ion-exchanged water and 5772 parts by mass of 48% aqueous sodium hydroxide solution were added, 2148 parts by mass of 1,1-bis(4-hydroxyphenyl)cyclohexane and 4 parts by mass of sodium hydrosulfite were added and dissolved therein, 8518 parts by mass of methylene chloride was added, and then 1000 parts by mass of phosgene was blown in at 23 to 27 ° C. for 60 minutes while stirring. After the end of the phosgene blowing, 38 parts by mass of p-tert-butylphenol was added, and 2 parts by mass of triethylamine was further added and stirred at 20 to 27 ° C. for 40 minutes to terminate the reaction. The methylene chloride layer containing the product was washed with dilute hydrochloric acid and pure water, and the methylene chloride was evaporated to obtain a polycarbonate having a repeating unit represented by the following formula (4) (hereinafter also referred to as "resin A").
The resulting resin A had a viscosity average molecular weight of 21,000 and a glass transition temperature (Tg) of 174°C.

[Synthesis Example 2]
A polycarbonate having a repeating unit represented by the following formula (5) (hereinafter also referred to as "resin B") was obtained in the same manner as in Synthesis Example 1, except that 9,9-bis(4-hydroxyphenyl)fluorene was used instead of 1,1-bis(4-hydroxyphenyl)cyclohexane in Synthesis Example 1.
The resulting resin B had a viscosity average molecular weight of 23,000 and a glass transition temperature (Tg) of 226°C.

[Synthesis Example 3]
100 parts by mass of 8-methyl-8-methoxycarbonyltetracyclo[4.4.0.1 ^2,5 .1 ^7,10 ]dodec-3-ene represented by the following formula (a), 18 parts by mass of 1-hexene (molecular weight regulator), and 300 parts by mass of toluene (solvent for ring-opening polymerization reaction) were charged into a reaction vessel substituted with nitrogen, and the solution was heated to 80°C. Next, 0.2 parts by mass of a toluene solution of triethylaluminum (0.6 mol/L) and 0.9 parts by mass of a toluene solution of methanol-modified tungsten hexachloride (concentration 0.025 mol/L) were added as polymerization catalysts to the solution in the reaction vessel, and the solution was heated and stirred at 80°C for 3 hours to carry out ring-opening polymerization reaction, thereby obtaining a ring-opened polymer solution. The polymerization conversion rate in this polymerization reaction was 97%.

1,000 parts by mass of the ring-opened polymer solution obtained above was charged into an autoclave, and 0.12 parts by mass of RuHCl(CO)[P( _C6H5 ) ₃ ] ₃ was added to this ring-opened polymer solution, and the solution was heated and stirred for 3 hours under conditions of a hydrogen gas pressure of 100 kg/ ^cm2 and _a reaction temperature of 165°C to carry out a hydrogenation reaction. After cooling the resulting reaction solution (hydrogenated polymer solution), the hydrogen gas pressure was released. This reaction solution was poured into a large amount of methanol to separate and recover a coagulated product, which was then dried to obtain a hydrogenated polymer (hereinafter also referred to as "resin D").
The resulting resin D had a number average molecular weight (Mn) of 32,000, a weight average molecular weight (Mw) of 137,000, and a glass transition temperature (Tg) of 165°C.

The near-infrared absorbing dyes used in the following examples were synthesized by commonly known methods, except for those that were commercially available.
Examples of the generally known methods include those described in JP-A-60-228448, JP-A-1-146846, JP-A-1-228960, JP-A-2009-108267, JP-A-2010-241873, and JP-A-2020-152915.

[Example 1]
<Preparation of Base Having Glass Substrate and Near-Infrared Absorption Layer>
A solution (polymer solution 1) was prepared by dissolving 3.5 parts by mass of dye A shown below as a squarylium dye, 2.0 parts by mass of dye C shown below as polymethine dyes, 5.0 parts by mass of dye D shown below, and 100 parts by mass of resin A obtained in Synthesis Example 1 in 733 parts by mass of chlorobenzene.

The polymer solution 1 was applied by a spin coater onto a transparent glass substrate "OA-10G (thickness 150 μm)" (manufactured by Nippon Electric Glass Co., Ltd.) cut to a size of 60 mm in length and 60 mm in width. The glass substrate coated with the polymer solution 1 was then heated at 110°C for 3 minutes using a hot plate, and further heated at 160°C for 20 minutes to produce a substrate 1 on which a near-infrared absorbing layer (thickness 2 μm) containing resin A, dye A, dye C, and dye D was formed on the glass substrate.

<Transmittance Measurement>
For the prepared substrate 1, a spectrophotometer (V-7200) manufactured by JASCO Corporation was used to measure the transmittance (Ti _n ) of light incident at an angle of incidence of 0° on the surface of the substrate 1 in the wavelength range of 300 to 1200 nm for every 1 nm of wavelength, and the average transmittance (Tb_AVE) for every 1 nm of wavelength in the wavelength range of 430 to 580 nm and the maximum transmittance (Tb_MAX) for every 1 nm of wavelength in the wavelength range of 700 to 1000 nm were calculated, and the shortest wavelength (Tb_50%) at which the transmittance was 50% was measured in the wavelength range of 700 to 1000 nm. The results are shown in Table 1.
Here, the transmittance of light incident on the surface of the substrate at an incident angle of 0° was measured for light that was transmitted perpendicularly through the substrate. In the following, the transmittance of light incident on the surface of the substrate or optical filter at an incident angle of 0° was measured in the same manner.

<Preparation of substrate for absorbance calculation>
A solution was prepared by adding 733 parts by mass of chlorobenzene to 100 parts by mass of the resin A obtained in Synthesis Example 1 (polymer solution 1R).
The polymer solution 1R was applied by a spin coater onto a transparent glass substrate "OA-10G (thickness 150 μm)" (manufactured by Nippon Electric Glass Co., Ltd.) cut to a size of 60 mm in length and 60 mm in width, and then heated on a hot plate at 110° C. for 3 minutes, and then further heated at 160° C. for 20 minutes to produce a substrate 1R in which a layer (thickness 2 μm) containing resin A was formed on the glass substrate.

For substrate 1R, in the same manner as for substrate 1, the transmittance (Tr _n ) for every 1 nm of wavelength of light incident on the surface of substrate 1R at an incident angle of 0° in the wavelength range of 300 to 1200 nm was measured, and the Tr _n and the value of Ti _n measured using substrate 1 were used to calculate the absorbance (Ai _n ) at each wavelength of 700 to 1000 nm based on the following formula, and the maximum value of the absorbance (Ai _n ) at each wavelength of 700 to 1000 nm was designated as Ai _n _MAX.

<Pigment retention rate>
Using GPHH-201 manufactured by ESPEC Corporation, the substrate 1 was heated at 150°C for 600 hours, and then allowed to cool to room temperature. For the substrate after heating, the transmittance (Tf n ) of light incident at an angle of incidence of 0° on the surface of the substrate after heating was measured again using a spectrophotometer (V-7200) manufactured by JASCO Corporation in the wavelength range of 300 to 1200 nm for every 1 nm of wavelength. Using the Tf _n and the value of Tr _n measured using the substrate 1R, the absorbance (Af _n ) at each wavelength of 700 to 1000 nm was calculated based on the following formula, and the maximum value of the absorbance (Af _n ) at each wavelength of 700 to 1000 nm was taken as _{Af n} _MAX.

The maximum absorbance retention rate (dye retention rate) [%] before and after heating at 150° C. for 600 hours was calculated using the following formula. The results are shown in Table 1.
Pigment retention rate (%) = (Af _n _MAX/ _Ain _MAX) x 100

<150℃ durability judgment>
In addition, the durability at 150°C (150°C durability) was judged based on the maximum absorbance retention rate (dye retention rate) [%] before and after heating at 150°C for 600 hours, according to the following criteria.
◎: Pigment retention rate is 85% or more. ○: Pigment retention rate is 80% or more and less than 85%. ×: Pigment retention rate is less than 80%. XX: Pigment retention rate cannot be measured due to embrittlement of the resin layer.

<Preparation of an optical filter having a dielectric multilayer film formed on both sides of a base material having a glass substrate and a near-infrared absorbing layer>
A dielectric multilayer film (IX) consisting of alternately laminated silica (SiO ₂ ) layers and titania (TiO ₂ ) layers (total of 18 layers) was formed as a first optical layer on one of the main surfaces of the substrate 1, and a dielectric multilayer film (X) consisting of alternately laminated silica (SiO ₂ ) layers and titania (TiO ₂ ) layers (total of 18 layers) was formed as a second optical layer on the other main surface of the substrate 1, thereby obtaining an optical filter having a thickness of approximately 0.157 mm.

The dielectric multilayer film (IX) is formed by alternately laminating silica ( _SiO2 ) layers and titania ( _TiO2 ) layers at a deposition temperature of 120° C. The dielectric multilayer film (X) is formed by alternately laminating silica ( _SiO2 ) layers and titania ( _TiO2 ) layers at a deposition temperature of 100° C.
In the dielectric multilayer films (IX) and (X), titania layers and silica layers were alternately laminated in the order of titania layer from the substrate 1 side, and the outermost layer of the optical filter was the silica layer.
The thickness and number of each layer were optimized using optical thin film design software (Essential Macleod, manufactured by Thin Film Center, Inc.) in accordance with the wavelength-dependent characteristics of the refractive index of the substrate 1 and the absorption characteristics of the dye used, so as to achieve an anti-reflection effect in the visible range and selective transmission and reflection performance in the near-infrared range.

<Spectral evaluation of optical filters>
For the prepared optical filter, the transmittance of light incident on the surface of the optical filter at an angle of incidence of 0° was measured for every 1 nm of wavelength using a spectrophotometer (V-7200) manufactured by JASCO Corporation, and the average transmittance (Tf_AVE) for every 1 nm of wavelength at wavelengths of 430 to 580 nm and the average transmittance (Tf_AVE750-900) for wavelengths of 750 to 900 nm were calculated, and the maximum transmittance (Tf_MAX) for wavelengths of 700 to 1000 nm and the minimum transmittance of the light blocking band Xa for wavelengths of 650 to 900 nm were measured. The results are shown in Table 1.

<Evaluation of near-infrared sensing sensitivity>
The near-infrared sensing sensitivity of the prepared optical filter was calculated based on the following formula. The larger the value of the near-infrared sensing sensitivity obtained by the following formula, the larger the difference in transmittance between the transmission band and the blocking band in the near-infrared region, which means that the near-infrared sensing sensitivity is high.
Near-infrared sensing sensitivity = (Tf_MAX) - (Tf_AVE750-900)

<Near-infrared sensing sensitivity determination>
Further, from the near-infrared sensing sensitivity value, the near-infrared sensing sensitivity was judged based on the following criteria.
◎: Near-infrared sensing sensitivity value is 80 or more. ○: Near-infrared sensing sensitivity value is 40 or more and less than 80. ×: Near-infrared sensing sensitivity value is less than 40.

[Examples 2 to 7 and Comparative Examples 1 to 2]
Polymer solutions were prepared in the same manner as in Example 1, except that the types of resins and dyes shown in Table 1 were used in the proportions shown in Table 1. Note that, only in Example 2, cyclopentanone was used as the solvent instead of chlorobenzene.
A substrate having a near-infrared absorbing layer formed on a glass substrate was produced in the same manner as in Example 1, except that the prepared polymer solution was used. An optical filter having a dielectric multilayer film formed on both sides thereof was produced in the same manner as in Example 1, except that the substrate was used.

The transmittance of each substrate was measured, the dye retention rate was calculated, and the durability at 150° C. was evaluated in the same manner as in Example 1, except that the substrate prepared above was used. The results are shown in Table 1. In Example 4, a substrate having a layer (thickness 2 μm) containing resin B formed on a glass substrate was used instead of the substrate 1R, in Example 6, a substrate having a layer (thickness 2 μm) containing resin C formed on a glass substrate was used instead of the substrate 1R, and in Comparative Example 1, a substrate having a layer (thickness 2 μm) containing resin D formed on a glass substrate was used instead of the substrate 1R.
FIG. 2 shows the spectral transmittance curve of the substrate prepared in Example 5.

In addition, except for using the prepared optical filter, the transmittance of each optical filter was measured and the near-infrared sensing sensitivity was evaluated in the same manner as in Example 1. The results are shown in Table 1.
FIG. 3 shows the spectral transmittance curve of the optical filter prepared in Example 5.

It should be noted that the substrate prepared in Comparative Example 1 could not be evaluated for durability at 150° C. due to embrittlement of the resin layer.
Moreover, the optical filter prepared in Comparative Example 2 had a low dye retention rate and therefore was poor in durability at 150° C., and was therefore unsuitable as the filter of interest.

The resins A to D in Table 1 are as follows:
Resin A: Resin obtained in Synthesis Example 1 Resin B: Resin obtained in Synthesis Example 2 Resin C: Polysulfone (Solvay, Udel P-1700NT11, glass transition temperature (Tg) = 180°C)
Resin D: Resin obtained in Synthesis Example 3

The dyes A to G in Table 1 are as follows. Each of these dyes was dissolved in dichloromethane so that the absorbance at the maximum absorption wavelength was 1.0, and the absorption spectrum was measured in the wavelength range of 300 to 1000 nm using a spectrophotometer (V-7200) manufactured by JASCO Corporation, to measure the maximum absorption wavelength λmax of each dye.

Dye A (squarylium dye): λmax=712 nm

Dye B (squarylium dye): λmax=703 nm

・Dye C (polymethine dye): λmax = 721 nm

Dye D (polymethine dye): λmax = 770 nm

・Dye E: λmax=394nm

Dye F (squarylium dye): λmax = 868 nm

・Dye G: λmax=760nm

[Example 8]
<Preparation of a substrate consisting only of a near-infrared absorbing layer containing a near-infrared absorbing dye>
Using resin A, dye A, dye C, and dye D in the proportions shown in Table 2, and using dichloromethane, a near-infrared absorbing dye-containing resin solution having a solid content concentration of 20 mass % was prepared.
The obtained near-infrared absorbing dye-containing resin solution was cast onto a smooth glass plate, dried at 20° C. for 8 hours, and then peeled off from the glass plate. The peeled coating film was further dried at 100° C. under reduced pressure for 8 hours to produce a substrate 8 consisting of only a near-infrared absorbing layer containing a near-infrared absorbing dye, with a thickness of 0.1 mm, a length of 60 mm, and a width of 60 mm.

<Preparation of substrate for absorbance calculation>
Resin A and dichloromethane were used to prepare a resin solution having a solid content concentration of 20% by mass.
The prepared resin solution was cast onto a smooth glass plate, dried at 20° C. for 8 hours, and then peeled off from the glass plate. The peeled coating film was further dried at 100° C. under reduced pressure for 8 hours to prepare a substrate for absorbance calculation having a thickness of 0.1 mm, length of 60 mm, and width of 60 mm.

The transmittance of each of the substrates 8 was measured, the dye retention rate was calculated, and the durability at 150°C was evaluated in the same manner as in Example 1, except that substrate 8 was used instead of substrate 1. In Example 8, the substrate for absorbance calculation prepared above was used instead of substrate 1R. The results are shown in Table 2.

<Preparation of an optical filter having a dielectric multilayer film formed on both sides of a substrate consisting of only a near-infrared absorbing layer>
In the same manner as in Example 1, an optical filter having a dielectric multilayer film formed on both main surfaces of a substrate 8 was produced.
Except for using the prepared optical filter, the transmittance of each optical filter was measured and the near-infrared sensing sensitivity was evaluated in the same manner as in Example 1. The results are shown in Table 2.

<Punching crack evaluation>
Both sides of the prepared optical filter were covered with a polyethylene protective film having a thickness of 50 μm, and the optical filter covered with the protective film was placed on a polyester film having a thickness of 250 μm as an underlay, and the optical filter covered with the protective film was chipped into a size of 4.5 mm x 4.5 mm using a punching blade mold shown in FIG. 4. As the punching blade mold, a punching blade mold having an inner taper angle of 0° and a cutting edge angle of 50° was used. In FIG. 4, a punching blade mold having an inner taper angle exceeding 0° is shown in order to show what the inner taper angle is, but in reality, as described above, the inner taper angle is 0°, so FIG. 4 is simply an explanatory diagram that is different from the shape of the punching blade mold used in this evaluation.

As described above, the optical filter after punching out the chip was visually inspected for the presence or absence of cracks. The results are shown in Table 2. When there were no cracks in the optical filter after punching out the chip, it was marked "absent", and when there were cracks in the optical filter after punching out the chip, it was marked "present".
If there are no cracks in the optical filter after the chips have been punched out, it is possible to narrow the punching distance when punching the chips out of the optical filter. Therefore, an optical filter that has no cracks in the optical filter after the chips have been punched out can be said to be an optical filter with excellent mass-producibility.

[Examples 9 to 14 and Comparative Examples 3 to 5]
Near infrared absorbing dye solutions were prepared in the same manner as in Example 8, except that the types of resins and dyes shown in Table 2 were used in the proportions shown in Table 2.
A substrate consisting only of a near-infrared absorbing layer was produced in the same manner as in Example 8, except that the prepared near-infrared absorbing dye solution was used. Then, an optical filter having a dielectric multilayer film formed on both sides thereof was produced in the same manner as in Example 8, except that the substrate was used.

The transmittance of each substrate was measured, the dye retention rate was calculated, and the durability at 150°C was evaluated in the same manner as in Example 8, except that the substrate prepared was used. The results are shown in Table 2. In Example 11, a substrate using resin B instead of resin A was used in the preparation of the substrate for absorbance calculation, in Example 13, a substrate using resin C instead of resin A was used in the preparation of the substrate for absorbance calculation, and in Comparative Example 3, a substrate using resin D instead of resin A was used in the preparation of the substrate for absorbance calculation.

In addition, the transmittance of each optical filter was measured and the near-infrared sensing sensitivity and punching cracks were evaluated in the same manner as in Example 8, except that the prepared optical filter was used. The results are shown in Table 2.

The substrate prepared in Comparative Example 3 could not be evaluated for durability at 150° C. due to embrittlement of the resin layer. Furthermore, the optical filter prepared in Comparative Example 3 was not suitable for use as the filter of interest due to punching cracks.
Moreover, the optical filters prepared in Comparative Examples 4 and 5 had low dye retention and therefore poor durability at 150° C., and were therefore unsuitable for use as the filter of interest.

In addition, the resins A to D and the dyes A to G in Table 2 are the same as those in Table 1.
The dyes H to M in Table 2 are as follows: The maximum absorption wavelength λmax of each of these dyes was measured in the same manner as above.

・Dye H: λmax=770nm

・Dye I: λmax=738nm

・Dye J: λmax=704nm

・Dye K: λmax=429nm

・Dye L: λmax=550nm

・Dye M: λmax=606nm

[Example 15]
<Preparation of Base Material Having Resin Substrate and Near-Infrared Absorption Layer>
100 parts by mass of Resin A was dissolved in methylene chloride to prepare a solution with a polymer concentration of 20% by mass.
The obtained solution was cast onto a smooth glass plate, dried at 20° C. for 8 hours, and then peeled off from the glass plate. The peeled coating film was further dried under reduced pressure at 100° C. for 8 hours to prepare a resin substrate having a thickness of 0.1 mm, a length of 60 mm, and a width of 60 mm.

Separately, 100 parts by mass of resin A, 1.4 parts by mass of dye A, 0.8 parts by mass of dye C, 2.0 parts by mass of dye D and 733 parts by mass of chlorobenzene were mixed to prepare a near infrared absorbing dye-containing resin solution.
The near-infrared absorbing dye-containing resin solution was applied to one side of the obtained resin substrate using a bar coater, and the solution was heated in an oven at 110° C. for 3 minutes, and then heated at 130° C. for 30 minutes to remove the solvent, thereby forming a near-infrared absorbing layer. At this time, the coating conditions of the bar coater were adjusted so that the thickness of the obtained near-infrared absorbing layer was 2.5 μm.
In a similar manner, a near-infrared absorbing layer (thickness: 2.5 μm) was formed on the other surface of the resin substrate, thereby producing a base material 15 having near-infrared absorbing layers formed on both surfaces of the resin substrate.

<Preparation of substrate for absorbance calculation>
Resin A and dichloromethane were used to prepare a resin solution having a solid content concentration of 20% by mass.
The prepared resin solution was cast onto a smooth glass plate, dried at 20° C. for 8 hours, and then peeled off from the glass plate. The peeled coating film was further dried at 100° C. under reduced pressure for 8 hours to prepare a substrate for absorbance calculation having a thickness of 0.105 mm, length of 60 mm, and width of 60 mm.

The transmittance of each of the substrates 15 was measured, the dye retention rate was calculated, and the durability at 150°C was evaluated in the same manner as in Example 1, except that substrate 15 was used instead of substrate 1. In Example 15, the substrate for absorbance calculation prepared above was used instead of substrate 1R. The results are shown in Table 3.

<Preparation of an optical filter having a dielectric multilayer film formed on both sides of a base material having a resin substrate and a near-infrared absorbing layer>
In the same manner as in Example 1, an optical filter having a dielectric multilayer film formed on both main surfaces of a substrate 15 was produced.
Except for using the prepared optical filter, the transmittance of each optical filter was measured, and the near-infrared sensing sensitivity and punching cracks were evaluated in the same manner as in Example 8. The results are shown in Table 3.

[Examples 16 to 21 and Comparative Examples 6 to 7]
Near infrared absorbing dye-containing resin solutions were prepared in the same manner as in Example 15, except that the types of resins and dyes shown in Table 3 were used in the ratios shown in Table 3. Note that, only in Example 16, cyclopentanone was used instead of chlorobenzene as the solvent.
Using the prepared near-infrared absorbing dye-containing resin solution, a substrate having a near-infrared absorbing layer formed on a resin substrate was produced in the same manner as in Example 15, except that the resin substrate described below was used. Then, an optical filter having a dielectric multilayer film formed on both sides was produced in the same manner as in Example 15, except that the substrate was used.
Examples 16 to 17, 19, 21 and Comparative Example 7: Resin substrates similar to Example 15. Example 18: Resin substrate obtained by using Resin B instead of Resin A in the preparation of the resin substrate of Example 15. Example 20: Resin substrate obtained by using Resin C instead of Resin A in the preparation of the resin substrate of Example 15. Comparative Example 6: Resin substrate obtained by using Resin D instead of Resin A in the preparation of the resin substrate of Example 15.

The transmittance of each substrate was measured, the dye retention rate was calculated, and the durability at 150°C was evaluated in the same manner as in Example 15, except that the substrate prepared was used. The results are shown in Table 3. In Example 18, a substrate using resin B instead of resin A was used in the preparation of the substrate for absorbance calculation, in Example 20, a substrate using resin C instead of resin A was used in the preparation of the substrate for absorbance calculation, and in Comparative Example 6, a substrate using resin D instead of resin A was used in the preparation of the substrate for absorbance calculation.

In addition, the transmittance of each optical filter was measured and the near-infrared sensing sensitivity and punching cracks were evaluated in the same manner as in Example 15, except that the prepared optical filter was used. The results are shown in Table 3.

The substrate prepared in Comparative Example 6 could not be evaluated for durability at 150° C. due to embrittlement of the resin layer. Furthermore, the optical filter prepared in Comparative Example 6 was not suitable for use as the filter of interest due to punching cracks.
Moreover, the optical filter prepared in Comparative Example 7 had a low dye retention rate and therefore was poor in durability at 150° C., and was therefore unsuitable as the filter of interest.

Note that resins A to D and dyes A to G in Table 3 are the same as those in Table 1.

10: Base material 11: Near infrared absorbing layer 12: Glass substrate 13: Resin layer other than near infrared absorbing layer (resin substrate)
14: Near infrared absorbing layer (substrate consisting of only a near infrared absorbing layer)

Claims (12)

A substrate having a near infrared absorbing layer containing a resin and a near infrared absorbing compound,
The resin contains a polycarbonate having a repeating unit represented by the following formula (1):
The substrate has a retention rate of 80% or more of the maximum absorbance in the wavelength region of 700 to 1000 nm before and after heat treatment in air at 150° C. for 600 hours.

[In the formula, Z, together with the carbon atom to which Z is bonded, forms a cyclic hydrocarbon group having 5 to 15 carbon atoms which may have a substituent; R ^1a and R ^1b are the same or different and are an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 5 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 14 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an acyl group having 2 to 10 carbon atoms, an alkoxycarbonyl group having 2 to 4 carbon atoms, a halogen atom, a nitro group, or a cyano group; and m1 and m2 are the same or different and are an integer of 0 to 4.] The substrate according to claim 1, which has a transmission wavelength band in the wavelength range of 430 to 580 nm, in which the transmittance of light incident at an incident angle of 0° is 40% or more. 3. The substrate according to claim 1 or 2, wherein the near infrared absorbing compound comprises at least one compound selected from the group consisting of a squarylium-based compound, a phthalocyanine-based compound, a dithiol-based compound, a diimmonium-based compound, and a polymethine-based compound (the polymethine-based compound is a compound other than a squarylium-based compound). The substrate according to any one of claims 1 to 3 , wherein the near infrared absorbing compound comprises a polymethine compound. The near infrared absorbing compound is
A polymethine compound,
The substrate according to any one of claims 1 to 4, comprising a near infrared absorbing compound having an absorption maximum wavelength λmax in a wavelength range of 680 to 1000 nm in an absorption spectrum measured in a wavelength range of 300 to 1000 nm using a solution of the near infrared absorbing compound dissolved in dichloromethane (provided that the near infrared absorbing compound is a compound other than a polymethine compound). The substrate according to any one of claims 1 to 5 , further comprising a compound having a maximum absorption wavelength λmax in the wavelength region of 350 to 420 nm. The substrate is
a base material having a glass substrate and the near infrared absorbing layer;
A substrate having the near-infrared absorbing layer and a resin layer other than the near-infrared absorbing layer, or
The substrate according to any one of claims 1 to 6 , which is a substrate consisting of only the near infrared absorbing layer. An optical filter comprising a substrate according to any one of claims 1 to 7 and a dielectric multilayer film on at least one surface of the substrate. 9. The optical filter according to claim 8 , which has an average transmittance of 70% or less for light having an incident angle of 0° in a wavelength region of 750 to 900 nm. A first transmission wavelength band having a transmittance of 40% or more for light having an incident angle of 0° in a wavelength range of 400 to 700 nm,
A second transmission wavelength band having a transmittance of 40% or more for light having an incident angle of 0° in a wavelength region of 750 to 1000 nm,
Having a light blocking band (Xa) between the first transmission wavelength band and the second transmission wavelength band,
The optical filter according to claim 8 or 9 . The optical filter according to any one of claims 8 to 10 , which is for use in an optical sensor device. An optical sensor device comprising the optical filter of claim 11 .