JP7459709B2 - optical filter - Google Patents

Description

The present invention relates to an optical filter.

In imaging devices using solid-state imaging elements, optical filters are used that transmit light in the visible range and block light in the near-infrared range in order to reproduce color tones well and obtain clear images. One known example of an optical filter is a near-infrared light cut filter that has a substrate containing a dye and a resin, and a dielectric multilayer film, disposed on a glass substrate.

From the viewpoint of suppressing flare and ghost phenomena, the dye used in the optical filter is preferably a near-infrared absorbing dye that has excellent light blocking properties for near-infrared light (wavelength 720 to 760 nm). In recent years, there has been a demand for dyes with high transmittance in the blue band (wavelength 450 to 550 nm). For example, Patent Document 1 discloses the following compound as a near-infrared absorbing dye with improved transmittance in the blue band.

Japanese Patent No. 6470650

However, according to the inventors' investigations, the dye described in Patent Document 1 has the drawback of being insufficient in transmittance in the blue band and poorly soluble in resin, which places limitations on its applications and the configuration of optical filters.

The present invention has been made in view of the above-mentioned conventional circumstances, and provides a near-infrared absorbing dye that has excellent near-infrared light shielding properties and sufficiently high transmittance in the blue band, and optical fibers containing the dye. The problem to be solved is to provide a filter.

The optical filter according to one aspect of the present invention is as follows.
An optical filter comprising a base material,
The base material has a resin layer,
The resin layer contains near-infrared absorbing dye A and a resin,
An optical filter, wherein the near-infrared absorbing dye A satisfies all of the following (i-1) to (i-3) in a spectral transmittance curve at a wavelength of 350 to 1200 nm measured after being dissolved in dichloromethane.
(i-1) It has an absorption maximum wavelength λmax (A) in the wavelength range of 720 to 760 nm.
(i-2) When the absorbance at the absorption maximum wavelength λmax (A) is set to 1, the maximum absorbance value ε _A in the wavelength range of 450 to 550 nm satisfies the following conditions.
1/ε _A ≧400
(i-3) When the absorbance at the absorption maximum wavelength λmax (A) is set to 1, the average absorbance value ε _B in the wavelength range of 450 to 470 nm satisfies the following condition.
1/ε _B ≧800

The near-infrared absorbing dye of the present invention has excellent near-infrared light blocking properties and sufficiently high transmittance in the blue band. Further, the near-infrared absorbing dye of the present invention has excellent solubility in resin.

FIG. 1 is a cross-sectional view that illustrates an example of an optical filter according to an embodiment. FIG. 2 is a diagram showing the spectral transmittance curve of the composite coating film of Test Example 5. FIG. 3 is an enlarged view showing the spectral transmittance curve of the composite coating film of Test Example 5.

Hereinafter, an embodiment of the present invention will be described.
In this specification, near infrared absorbing dye A may be abbreviated as "dye A", near infrared absorbing dye B as "dye B", and ultraviolet absorbing dye as "UV dye".
In this specification, a compound represented by formula (1) is referred to as compound (1). The same applies to compounds represented by other formulas. In addition, a group represented by formula (1) is also referred to as group (1), and the same applies to groups represented by other formulas.

In this specification, the term "internal transmittance" refers to the transmittance obtained by subtracting the influence of interface reflection from the actually measured transmittance, which is expressed by the formula {actual transmittance/(100-reflectance)}×100.
In this specification, the transmittance of the substrate or resin layer is always the "internal transmittance" even when it is described as "transmittance". On the other hand, the transmittance measured by dissolving the dye in a solvent such as dichloromethane and the transmittance of the optical filter are actually measured transmittances.

In this specification, for a specific wavelength range, a transmittance of 90% or more means that the transmittance is not less than 90% in the entire wavelength range, that is, the minimum transmittance is 90% or more in that wavelength range. means. Similarly, for a specific wavelength range, a transmittance of 1% or less means that the transmittance does not exceed 1% in the entire wavelength range, that is, the maximum transmittance in that wavelength range is 1% or less. . The same applies to internal transmittance. The average transmittance and average internal transmittance in a specific wavelength range are the arithmetic averages of the transmittance and internal transmittance for every 1 nm in the wavelength range.
In this specification, "~" representing a numerical range includes the upper and lower limits.

[Optical Filter]
An optical filter according to one embodiment of the present invention (hereinafter, also referred to as "the present filter") includes a substrate. The substrate has a resin layer, and the resin layer contains near-infrared absorbing dye A and a resin.

Also, as shown in FIG. 1, the optical filter 10 can include, for example, a resin layer 12 on a support 11.

<Base material>
(resin)
The resin layer included in the base material of this filter contains resin.
The resin is preferably a transparent resin (resin having transparency).
Examples of transparent resins include cycloolefin polymers (COP) or cycloolefin copolymers (COC) such as norbornene resin; polyimide resins (PI); polycarbonate resins (PC); polyester resins such as polyethylene terephthalate (PET) and polybutylene terephthalate. ; polyolefin resins such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymers; acrylic resins such as polyacrylate and polymethyl methacrylate; urethane resins, vinyl chloride resins; fluororesins; polyvinyl butyral resins; polyvinyl alcohol resins.

Among them, from the viewpoint of being able to achieve both transparency in the visible light range (wavelength 400 to 700 nm), heat resistance, and glass transition temperature, we select cycloolefin polymers, cycloolefin copolymers, polyimide resins, polycarbonate resins, polyethylene terephthalate, acrylic resins, and epoxy resins. At least one transparent resin selected from the group consisting of:

Among these, polyethylene terephthalate and polyimide are particularly preferred from the viewpoint of compatibility between transparency in the visible light region (wavelength 400 to 700 nm), heat resistance, and adhesion to the multilayer film.
These resins may be used alone or in combination of two or more.

(Characteristics of near-infrared absorbing dye A)
The resin layer included in the base material of this filter contains near-infrared absorbing dye A.
Near-infrared absorbing dye A is an optical filter that satisfies all of the following (i-1) to (i-3) in a spectral transmittance curve at a wavelength of 350 to 1200 nm measured by dissolving it in dichloromethane.
(i-1) It has an absorption maximum wavelength λmax (A) in the wavelength range of 720 to 760 nm.
(i-2) When the absorbance at the absorption maximum wavelength λmax (A) is set to 1, the maximum absorbance value ε _A in the wavelength range of 450 to 550 nm satisfies the following condition.
1/ε _A ≧400
(i-3) When the absorbance at the absorption maximum wavelength λmax (A) is set to 1, the average absorbance value ε _B in the wavelength range of 450 to 470 nm satisfies the following condition.
1/ε _B ≧800

By satisfying the above (i-1), dye A becomes a dye that has excellent near-infrared light blocking properties.

By satisfying the above (i-2), the dye A becomes a dye having high transmittance in the blue wavelength region.
1/ε _A is preferably 450 or more, and more preferably 480 or more.

By satisfying (i-3) above, dye A becomes a dye with higher transmittance in the blue band.
1/ε _B is preferably 900 or more, more preferably 1000 or more.

It is preferable that dye A further satisfies the following (i-4) in a spectral transmittance curve at wavelengths of 350 to 1,200 nm, which is measured after dissolving the dye in dichloromethane.
(i-4) When the absorbance at the absorption maximum wavelength λmax(A) is set to 1, a wavelength _λε0.002 at which the absorbance exceeds 0.002 in a wavelength range of 500 nm or less satisfies the following condition:
λ ε _0.002 ≦ 455 nm

When dye A satisfies (i-4) above, the transmittance is increased to a shorter wavelength range, so that the amount of light taken in in the blue band can be increased. This makes the dye A a dye with higher transmittance in the blue band.
λ _ε0.002 is preferably 453 nm or less, more preferably 450 nm or less.

It is preferable that dye A further satisfies the following (i-5) in a spectral transmittance curve at wavelengths of 350 to 1,200 nm, which is measured after dissolving the dye in dichloromethane.
(i-5) When the transmittance at the absorption maximum wavelength λmax (A) is set to 10%, the average transmittance in the wavelength range of 650 to 700 nm is 60% or more.

By satisfying (i-5) above, dye A becomes a dye that not only has high transmittance in the blue band but also has high transmittance in the red band (wavelength 650 to 700 nm).
The average value of the transmittance in (i-5) above is preferably 65% or more, more preferably 68% or more.

Here, it is preferable that the dye A satisfies the following (ii-1) and (ii-2) in the resin layer containing only the dye A and the resin.
(ii-1) When the internal transmittance of the absorption maximum wavelength λmax (pA) of the near infrared absorbing dye A is set to 10%, the average internal transmittance at wavelengths of 450 to 550 nm is 97.0% or more, and the minimum internal transmittance at wavelengths of 450 to 550 nm is 96.5% or more.
(ii-2) When the internal transmittance of the absorption maximum wavelength λmax (pA) of the near infrared absorbing dye A is set to 10%, the absolute value |Xa-Xb| of the difference between the shortest wavelength value (Xa) at which the internal transmittance becomes 80% and the longest wavelength value (Xb) at which the internal transmittance becomes 80% is 140 nm or more.

By satisfying the above condition (ii-1), the transmittance of the resin layer in the blue band can be increased.
The internal average transmittance in the wavelength range of 450 to 550 nm in (ii-1) above is preferably 97.5% or more, more preferably 98.0% or more. Further, the minimum internal transmittance at a wavelength of 450 to 550 nm is preferably 96.8% or more, more preferably 97.0% or more.

By satisfying the above condition (ii-2), the near-infrared light shielding property of the resin layer can be improved.
The absolute value |Xa−Xb| in (ii-2) above is preferably 145 nm or more, more preferably 150 nm or more.

Dye A has good solubility in organic solvents and therefore good compatibility with resins. As a result, even if the thickness of the substrate is thin, it has excellent spectral characteristics, and the optical filter can be made smaller and thinner. In addition, since the thickness of the substrate can be thinned, the thermal expansion of the substrate due to heating can be suppressed, and the occurrence of cracks in the reflective layer or anti-reflective layer when forming the layer can be suppressed. That is, when forming the reflective layer or anti-reflective layer, depending on the material, a heat treatment may be performed, and if the thickness of the substrate is thick, there is a risk that cracks will occur in the layer due to the expansion of the substrate during the heat treatment. In addition, since dye A has excellent solubility in resins, the method of forming the resin layer can be freely selected. For example, a single layer containing dye A in resin may be used as the substrate, or as shown in FIG. 1, a resin layer 12 containing dye A in resin may be formed on a support 11 to form the substrate, and the thickness of the resin layer has a high degree of freedom.

It is preferable that the dye A is a compound represented by the following formula (1).

The symbols in formula (1) are as follows:

X ⁻ is a monovalent anion species. Examples of monovalent anion species include PF ₆ ⁻ , BF ₄ ⁻ , N(SO ₂ CF ₃ ) ₂ ⁻ , CF ₃ SO ₃ ⁻ , ReO ₄ ⁻ , ClO ₄ ⁻ , Cl ⁻ , Br ⁻ , I ⁻ , BPh ₄ ⁻ , B(C ₆ F ₅ ) ₄ ⁻ , CF ₃ COO ⁻ , C(SO ₂ CF ₃ ) ₃ ⁻ , p-toluenesulfonyl anion, and the like.
In addition, Ph means a phenyl group.

Among these, from the viewpoint of increasing the light resistance of dye A, X ⁻ is preferably selected from PF ₆ ⁻ , BF ₄ ⁻ , and N(SO ₂ CF ₃ ) ₂ ⁻ .

m is 0 or 1, preferably 1.
R ₁ is a monovalent anionic group when m is 0. Examples of the monovalent anionic group include anionic groups represented by any of the following (C1) to (C6).

In formulas (C1) to (C6), R ²⁰¹ to R ²¹⁴ each independently represent a hydrogen atom, an aryl group having 5 to 20 carbon atoms, or an alkyl group having 1 to 10 carbon atoms which may have a substituent. show. Examples of the substituent include a halogen atom or an alkoxy group having 1 to 10 carbon atoms.

When m is 1, R ₁ is a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms which may have a substituent, or a substituent. It is an aralyl group having 7 to 13 carbon atoms, or -NR ₉ R ₁₀ .

Examples of the halogen atom in R ₁ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

The number of carbon atoms in the alkyl group in R ₁ is preferably 1 to 10, more preferably 1 to 6. Examples of the alkyl group having 1 to 6 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, isobutyl group, and tert-butyl group.
Among them, a methyl group is particularly preferred from a synthetic viewpoint.

Examples of the aryl group having 6 to 12 carbon atoms for _R1 include groups that bond via a carbon atom constituting an aromatic ring (e.g., a benzene ring, a naphthalene ring, a biphenyl ring, a furan ring, a thiophene ring, a pyrrole ring, etc.) contained in an aromatic compound.
Among these, a phenyl group is preferred from the viewpoint of not impairing the transmittance in the blue range.

Examples of the aryl group having 7 to 13 carbon atoms for _R1 include linear or branched, saturated or unsaturated hydrocarbon groups or saturated cyclic hydrocarbon groups which may contain a saturated ring structure and are substituted with one or more aryl groups.
Among these, araryl groups having a phenyl group are preferred from the viewpoint of not impairing the transmittance in the blue range.

Examples of the substituent that _R1 may have include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, a hydroxyl group, a carboxy group, a sulfo group, a cyano group, an amino group, an N-substituted amino group, a nitro group, an alkoxycarbonyl group, a carbamoyl group, an N-substituted carbamoyl group, and an imido group.

R ₉ and R ₁₀ are each independently an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms which may have a substituent, or a carbonyl group having 1 to 12 carbon atoms which may have a substituent.

Specific examples of the alkyl group and aryl group in R ₉ and R ₁₀ and specific examples of the substituent that R ₉ and R ₁₀ may have are the same as those for R ₁ .

Examples of the carbonyl group having 1 to 12 carbon atoms in R ₉ and R ₁₀ include an acetyl group, an ethanoyl group, a propanoyl group, a benzoyl group, a trifluoroacetyl group, a pentafluoroethanoyl group, and the like.

Among these, from the viewpoint of not impairing the transmittance in the blue wavelength region and from the viewpoint of synthesis, R ₁ is preferably a hydrogen atom, a methyl group, a phenyl group, a diphenylamino group, an N-ethylamide group, or an N-ethyl-2,2,2-trifluoroacetamide group, and more preferably a hydrogen atom, a methyl group, or a phenyl group.

R ₂ to R ₇ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or a cycloalkyl group having 6 to 12 carbon atoms which may have a substituent. It is an aryl group or an aralyl group having 7 to 13 carbon atoms which may have a substituent. Two adjacent R ₂ to R ₇ may be linked to each other to form a 5- to 8-membered ring.

Specific examples of the halogen atom, alkyl group, aryl group having 6 to 12 carbon atoms, and aralyl group in R ₂ to R ₇ and specific examples of the substituent that R ₂ to R ₇ may have are the same as those for R ₁ . be.

The number of carbon atoms in the cycloalkyl group for R ₂ to R ₇ is preferably 3 to 10, and more preferably 6 to 10. Examples of the cycloalkyl group having 6 to 10 carbon atoms include a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, and an adamantyl group.

Among these, from the viewpoint of not impairing the transmittance in the blue wavelength region and from the viewpoint of synthesis, R ₂ to R ₅ are preferably a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and more preferably a hydrogen atom.

Further, R ₆ to R ₇ are preferably an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms which may have a substituent, from the viewpoint of increasing the transmittance in the blue band. More preferably, they are a secondary alkyl group having 1 to 12 carbon atoms, a tertiary alkyl group having 1 to 12 carbon atoms, or a phenyl group having substituents at the 2- and 6-positions, such as an isopropyl group, a tert-butyl group, More preferably, it is a sec-butyl group, 2,6-dimethylphenyl group, 2,4,6-trimethylphenyl group, 2,6-diisopropylphenyl group, or 2,4,6-triisopropylphenyl group.

Moreover, it is more preferable that the dye A is a compound represented by the following formula (2).

The symbols in formula (2) are as follows.

The definitions of X ⁻ and R ₁ to R ₅ are the same as those in formula (1).

R ₁₁ and R ₁₂ each independently represent an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms.

The alkyl group in R ₁₁ and R ₁₂ preferably has 1 to 8 carbon atoms, more preferably 1 to 5 carbon atoms. Examples of the alkyl group having 1 to 5 carbon atoms include methyl group, ethyl group, isopropyl group, and tert-butyl group.

The number of carbon atoms in the alkoxy group in R ₁₁ and R ₁₂ is preferably 1 to 8, more preferably 1 to 6. Examples of the alkoxy group having 1 to 6 carbon atoms include methoxy group, ethoxy group, and isopropoxy group.

Since R ₁₁ and R ₁₂ are an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms, dye A takes a conformation in which the phenyl group is orthogonal to the π conjugation plane. This breaks the π conjugation between the phenyl group and dye A, and the phenyl group comes to have an induced electron-withdrawing effect. Due to this electron-withdrawing effect, compound (2) has absorption in the near-infrared region of 720 to 760 nm, and it is possible to increase the transmittance in the blue band.

Among these, from the viewpoint of synthesis, R ₁₁ and R ₁₂ are preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms, and include methyl group, ethyl group, etc. More preferably, it is an isopropyl group.

R ₁₃ is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.

The number of carbon atoms in the alkyl group for R ₁₃ is preferably 1 to 8, and more preferably 1 to 5. Examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, an isopropyl group, and a tert-butyl group.

The number of carbon atoms in the alkoxy group in R ₁₃ is preferably 1 to 8, more preferably 1 to 6. Examples of the alkoxy group having 1 to 6 carbon atoms include methoxy group, ethoxy group, and isopropoxy group.

Among these, from the viewpoint of synthesis, R ₁₃ is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms, and further preferably a methyl group, an ethyl group, or an isopropyl group.

Moreover, when R ₁₃ is other than a hydrogen atom, it is preferable from a synthetic viewpoint that R ₁₃ is the same as R ₁₁ and R ₁₂ .

More specifically, the compound (2) is represented by formulas (2)-1 to (2)-24, in which the atoms or groups bonded to each skeleton are the atoms or groups shown in Table 1 below. Compounds such as

Among these, the compounds represented by formulae (2)-1 and (2)-2 are preferred from the viewpoint of ease of synthesis.
From the viewpoint of improving the light resistance of dye A, X ⁻ is preferably selected from PF ₆ ⁻ , BF ₄ ⁻ , and N(SO ₂ CF ₃ ) ₂ ^— .

(Method for producing dye A)
The method for producing dye A will be explained using the method for producing compound (2)-30 in which R ₁ to R ₅ in compound (2) are hydrogen atoms, but the method for producing dye A is not limited thereto.
The route for obtaining compound (2)-30 is shown below.

<Step 1>
The starting material, trimethylsilylacetylene, tetrakis(triphenylphosphine)palladium(0), copper iodide, and diethylamine are added to a recovery flask. After degassing the flask, replace with nitrogen and heat and stir. After the reaction is complete, the solvent is removed under reduced pressure, water is added, and the mixture is extracted with dichloromethane. Dichloromethane is removed under reduced pressure, and purification is performed to obtain intermediate 1.

<Step 2>
Add intermediate 1 and methanol to a recovery flask and cool on ice. Add potassium carbonate and stir under a nitrogen stream. After the reaction is complete, filter to remove potassium carbonate from the reaction system, and distill the filtrate under reduced pressure. Add water to the resulting liquid and extract with dichloromethane. Dichloromethane is distilled under reduced pressure, and purification is performed to obtain intermediate 2.

<Step 3>
Add intermediate 2 and tetrahydrofuran to a recovery flask and stir under a nitrogen stream. Add n-butyllithium and stir. Then add ethyl formate dissolved in tetrahydrofuran and stir. After the reaction is complete, add water to stop the reaction and extract with dichloromethane. Dichloromethane is distilled off under reduced pressure, and the resulting solid is washed to obtain intermediate 3.

<Step 4>
Add intermediate 3, dichloromethane, and manganese oxide to an eggplant flask, and stir under a nitrogen stream. After the reaction is completed, the reaction solution is filtered to remove manganese oxide, and the filtrate is distilled off under reduced pressure. The resulting powder is washed to obtain Intermediate 4.

<Step 5>
Add intermediate 4, p-toluenesulfonic acid monohydrate, methanol, and toluene to an eggplant flask and stir. Thereafter, the solvent was distilled off under reduced pressure, and methanol and concentrated hydrochloric acid were added thereto, followed by stirring. After the reaction is completed, the reaction solution is ice-cooled, water is added to stop the reaction, and then extracted with dichloromethane. Dichloromethane is distilled off under reduced pressure, toluene and trifluoromethanesulfonic acid are added, and the mixture is stirred. After the reaction is completed, the reaction solution is ice-cooled, water is added to stop the reaction, and the toluene layer is extracted. Toluene is distilled off under reduced pressure, purification is performed, and the resulting powder is washed to obtain Intermediate 5.

<Step 6>
Intermediate 5 and tetrahydrofuran are added to an eggplant flask and stirred. Methylmagnesium bromide is added thereto, and the mixture is heated and stirred under a nitrogen stream. After the reaction is completed, the reaction solution is poured little by little into a 10% by mass acidic aqueous solution and stirred to stop the reaction. This solution is extracted with dichloromethane, the dichloromethane layer is washed with water, and then dichloromethane is distilled off under reduced pressure. Intermediate 6 is obtained by washing the obtained powder.

Examples of the 10% by mass acidic aqueous solution include hexafluorophosphoric acid aqueous solution, tetrafluoroboric acid aqueous solution, bis(trifluoromethanesulfonyl)imide aqueous solution, trifluoromethanesulfonic acid aqueous solution, perrhenic acid aqueous solution, perchloric acid aqueous solution, and hydrogen chloride. Examples include an aqueous acid solution, an aqueous hydrobromic acid solution, an aqueous hydroiodic acid solution, and the like.

<Step 7>
Intermediate 6, malonaldehyde dianilide hydrochloride, sodium acetate, acetic acid, and acetic anhydride are added to an eggplant flask, and the mixture is heated and stirred under a nitrogen stream. After the reaction is completed, the reaction solution is ice-cooled, water is added, and the reaction solution is filtered to recover powder. After refining the powder, the resulting solid is washed to obtain compound (2)-30.

(Near infrared absorbing dye B)
It is preferable that the resin layer further contains a near infrared absorbing dye B.
It is preferable that dye B satisfies the following (iii-1) and (iii-2) in a spectral transmittance curve at wavelengths of 350 to 1200 nm measured after dissolving it in dichloromethane.
(iii-1) The near infrared absorbing dye B has a maximum absorption wavelength λmax(B) in the wavelength range of 670 to 730 nm.
(iii-2) The maximum absorption wavelength λmax(B) and the maximum absorption wavelength λmax(A) satisfy the following condition:
λmax(B)<λmax(A)

When the resin layer contains dye B that satisfies the above (iii-1) and (iii-2), the near-infrared light blocking properties of the substrate are enhanced.

The resin layer containing dye A and dye B preferably satisfies all of the following (iv-1) to (iv-6).
(iv-1) Absolute value of the difference between the shortest wavelength value (Ya) at which the internal transmittance is 50% and the longest wavelength value (Yb) at which the internal transmittance is 50% | Ya - Yb | is in the range of 100 to 150 nm.
(iv-2) The shortest wavelength value (Ya) at which the internal transmittance is 50% is in the range of 630 to 680 nm.
(iv-3) Internal transmittance at a wavelength of 750 nm is 30% or less.
(iv-4) The average value of internal transmittance at a wavelength of 730 to 780 nm is 40% or less.
(iv-5) The average value of the internal transmittance at a wavelength of 680 to 740 nm is 10% or less, and the minimum value of the internal transmittance is 5% or less.
(iv-6) The average value of internal transmittance at a wavelength of 450 to 550 nm is 97% or more, and the minimum value of the internal transmittance is 94% or more.

By satisfying all of the above (iv-1) to (iv-6), it is possible to incorporate sufficient amounts of dye A and dye B into the base material, thereby enabling the transmittance of the blue band to be increased while adequately blocking near-infrared light.

The absolute value |Ya-Yb| in the above (iv-1) is preferably 105 to 150 nm, more preferably 110 to 150 nm. When the absolute value |Ya-Yb| is in this range, the substrate can block a wide range of the near-infrared region.

The wavelength value (Ya) in (iv-2) above is preferably 635 to 675 nm, more preferably 640 to 670 nm.

The internal transmittance in (iv-3) above is preferably 28% or less, more preferably 27% or less. When the internal transmittance is in this range, the substrate can block light in the long wavelength region of 750 nm.

The average value of the internal transmittance in (iv-4) above is preferably 37% or less, more preferably 35% or less. When the average value of the internal transmittance is within this range, the base material can have shielding properties over a wide range of near-infrared regions.

The average internal transmittance in (iv-5) above is preferably 9% or less, more preferably 8% or less. The minimum internal transmittance in (iv-5) above is preferably 4% or less, more preferably 3% or less. When the minimum internal transmittance is in this range, the substrate can adequately block light in the wavelength range of 680 to 740 nm.

The average value of the internal transmittance in (iv-6) above is preferably 97.5% or more, more preferably 98.0% or more. The minimum value of the internal transmittance in (iv-6) above is preferably 94.1% or more, more preferably 94.2% or more. When the internal transmittance is within this range, the transmittance of the base material in the blue band can be increased.

In addition, examples of the dye B include squarylium dyes represented by formula (BI) or formula (BII). In this specification, the dye represented by formula (BI) is also referred to as dye (BI), and the dye represented by formula (BII) is also referred to as dye (BII), and the same applies to other dyes.

However, the symbols in formula (BI) and formula (BII) are as follows.
Y is independently a divalent group represented by formula (101) or formula (102) in which one or more hydrogen atoms may be substituted with a halogen atom, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group; It is an organic group.

-( _CH2 ) _n1- (101)
In formula (101), n1 is 2 or 3.

-(CH ₂ ) _n2 -O-(CH ₂ ) _n3 - (102)
In formula (102), n2 and n3 are each independently an integer of 0 to 2, and n2+n3 is 1 or 2.

R ¹⁰¹ is independently a saturated or unsaturated hydrocarbon group having 1 to 12 carbon atoms, which may contain a saturated ring structure and may have a branch, a saturated cyclic hydrocarbon group having 3 to 12 carbon atoms, or a saturated cyclic hydrocarbon group having 3 to 12 carbon atoms; It represents an aryl group having 6 to 12 carbon atoms or an aralyl group having 7 to 13 carbon atoms.

R ¹⁰² is independently a hydrocarbon 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 between carbon atoms, an oxygen atom, or a saturated or unsaturated ring structure.

R ¹⁰³ , R ¹⁰⁴ , R ¹⁰⁵ and R ¹⁰⁶ independently represent a hydrogen atom, a halogen atom, or an alkyl group or alkoxy group having 1 to 10 carbon atoms.
n is 2 or 3.

In this specification, a saturated or unsaturated ring structure refers to a hydrocarbon ring or a heterocycle having an oxygen atom as a ring-constituting atom. Furthermore, this category also includes a structure in which an alkyl group having 1 to 10 carbon atoms is bonded to a carbon atom constituting the ring.

Furthermore, the aryl group refers to a group bonded via a carbon atom constituting an aromatic ring of an aromatic compound, such as a benzene ring, naphthalene ring, biphenyl, furan ring, thiophene ring, or pyrrole ring. Araryl group refers to a linear or branched saturated or unsaturated hydrocarbon group or a saturated cyclic hydrocarbon group which may include a saturated ring structure and is substituted with one or more aryl groups.

Dye (BI) and dye (BII) have a squarylium skeleton in the center of their 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, with fused ring structures on the left and right forming heterocycles containing the nitrogen atom and the carbon atoms at the 4th and 5th positions of the benzene ring.

Furthermore, the dye (BI) is bonded to the sulfonamide group represented by the formula (b1) at the 2-position of the benzene ring, which is present on the left and right, and the dye (BII) is bonded to the sulfonamide group represented by the formula (b1), which is present on the benzene ring, which is present on the left and right. is bonded to a sulfonamide group represented by formula (b2) at the 2-position of each.

In the dye (BI) and the dye (BII), the structure of the rings other than the benzene ring constituting the condensed ring structure that exists on each side is determined by Y, and each independently is a 5- or 6-membered heterocycle. It is. The divalent group Y constituting a part of the heterocycle may have a skeleton composed only of carbon atoms as shown in formula (101), or may not contain an oxygen atom as shown in formula (102). But that's fine. In formula (102), the position of the oxygen atom is not particularly limited. That is, a nitrogen atom and an oxygen atom may be bonded, or an oxygen atom may be bonded directly to a benzene ring. Further, an oxygen atom may be located between carbon atoms.

The left and right Ys may be the same or different, but are preferably the same from the viewpoint of productivity. Furthermore, R ¹⁰¹ to R ¹⁰⁶ may be the same or different on the left and right sides with the squarylium skeleton in between, but from the viewpoint of productivity, they are preferably the same.

As described above, dye (BI) and dye (BII) have a sulfonamide group bonded to the second position of the benzene ring bonded to the left and right of the squarylium skeleton, which allows them to have spectral transmittance characteristics in the near-infrared range equivalent to conventional squarylium dyes, while also improving the transmittance of light in the visible range, particularly light with wavelengths of 430 to 550 nm. This is thought to be because the sulfonamide group bonded to the benzene ring can suppress a decrease in the electron density of the nitrogen atom. In addition, because the sulfonamide group is a stable bond, stability against heat and light is also improved. Furthermore, solubility in resins is not impaired, making it possible to use them as dyes.

The dye (BI) and the dye (BII) have good solubility in organic solvents and therefore good compatibility with transparent resins. As a result, even if the thickness of the base material is reduced, it has excellent spectral characteristics, and the optical filter can be made smaller and thinner. Furthermore, since the thickness of the base material can be reduced, thermal expansion of the base material due to heating can be suppressed, and occurrence of cracks in reflective layers, for example, antireflection layers, can be suppressed when forming these layers. In other words, when forming reflective layers, anti-reflection layers, etc., heat treatment may be applied depending on the material. If the base material is thick, the expansion of the base material during heat treatment may cause cracks in those layers. may occur. Furthermore, from the viewpoint of solubility in organic solvents and compatibility with transparent resins, substituent R ¹⁰¹ is preferably a group having a branched structure.

Since the dye (BI) and the dye (BII) contain a sulfonamide group, they have good heat resistance and can suppress deterioration of the performance even during heat treatment of a reflective layer, an antireflection layer, etc. Also, from the viewpoint of heat resistance, the substituent R ¹⁰¹ is preferably a group having a branched structure.

Furthermore, dye (BI) and dye (BII) also have good light resistance. From the viewpoint of light resistance, the group bonded to the S atom of the sulfonamide group is preferably an alkyl group or an alkoxy group, and more preferably an alkyl group or an alkoxy group having 1 to 12 carbon atoms.

Y in the dye (BI) and the dye (BII) is preferably a divalent organic group represented by formula (103).
-CR ¹⁰⁷ ₂ -(CR ¹⁰⁸ ₂ ) _n4 - (103)

Formula (103) represents a divalent group whose left side is bonded to a benzene ring and whose right side is bonded to N, and n4 is 1 or 2. n4 is preferably 1. R ¹⁰⁷ is independently an alkyl group or alkoxy group having 1 to 12 carbon atoms which may be branched, and preferably an alkyl group or alkoxy group having 1 to 6 carbon atoms which may be branched. R ¹⁰⁸ is independently a hydrogen atom, or an alkyl group or alkoxy group having 1 to 12 carbon atoms which may be branched, and preferably a hydrogen atom, or an alkyl group or alkoxy group having 1 to 6 carbon atoms which may be branched.

It is particularly preferable that Y is any of the divalent organic groups represented by formulas (11-1) to (12-3). Formulas (11-1) to (12-3) all represent a divalent group whose left side is bonded to a benzene ring and whose right side is bonded to N.

-C(CH ₃ ) ₂ -CH(CH ₃ )- (11-1)
-C(CH ₃ ) ₂ -CH ₂ - (11-2)
-C(CH ₃ ) ₂ -CH(C ₂ H ₅ )- (11-3)
-C(CH ₃ ) ₂ -C(CH ₃ ) ₂ - (11-4)
-C(CH ₃ ) ₂ -C(CH ₃ )(C ₂ H ₅ )- (11-5)
-C(CH ₃ ) ₂ -C(CH ₃ )(CH(CH ₃ ) ₂ )- (11-6)
-C(CH ₃ ) ₂ -CH ₂ -CH ₂ - (12-1)
-C(CH ₃ ) ₂ -CH ₂ -CH(CH ₃ )- (12-2)
-C(CH ₃ ) ₂ -CH(CH ₃ )-CH ₂ - (12-3)

Among these, Y is preferably any of the groups (11-1) to (11-6).

The structural formulas of the dye (Bi) and the dye (Bii) in which Y is a preferable group are shown below. In formulas (Bi) and (Bii), R ¹⁰¹ to R ¹⁰⁶ have the same meanings as R ¹⁰¹ to R ¹⁰⁶ in formulas (BI) and (BII). Further, R ¹²¹ and R ¹²² are an alkyl group or alkoxy group having 1 to 6 carbon atoms which may have a branch, and R ¹²³ and R ¹²⁴ are a hydrogen atom or a carbon number 1 to 6 which may have a branch. 6 is an alkyl group or an alkoxy group.

From the viewpoints of solubility, heat resistance, and steepness of change in the vicinity of the boundary between the visible region and the near-infrared region in the spectral transmittance curve, R ¹⁰¹ of dye (BI) and dye (BII) is preferably independently a group represented by formula (4-1) or formula (4-2).

In formula (4-1) and formula (4-2), R ¹¹¹ , R ¹¹² , R ¹¹³ , R ¹¹⁴ and R ¹¹⁵ each independently represent a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms.

R ¹⁰³ and R ¹⁰⁴ in the dye (BI) and the dye (BII) are each preferably independently a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 6 carbon atoms, and more preferably a hydrogen atom.

In terms of light resistance, R ¹⁰² in dye (BI) is preferably independently an alkyl group or alkoxy group having 1 to 12 carbon atoms which may be branched, or a hydrocarbon group having 6 to 16 carbon atoms which has an unsaturated ring structure. Examples of the unsaturated ring structure include benzene, toluene, xylene, furan, and benzofuran. It is more preferable that R ¹⁰² is independently an alkyl group or alkoxy group having 1 to 12 carbon atoms which may be branched.

R ¹⁰⁵ and R ¹⁰⁶ of the dye (BII) do not significantly increase the molecular weight, and from the viewpoints of addition amount, reactivity to squarylium, solubility in resin, etc. Alkyl groups are more preferred.

As the dye (B1), the dye (Bi) or the dye (Bii) is more preferable.

The dye (BI) and the dye (BII) can be produced by a conventionally known method, for example, the method described in US Patent Application Publication No. 2014/0061505 and International Publication No. 14/088063.

(Other dyes)
The resin layer may further contain a UV dye as another dye.
Examples of UV dyes include merocyanine-based, oxazole-based, cyanine-based, naphthalimide-based, oxadiazole-based, oxazine-based, oxazolidine-based, naphthalic acid-based, styryl-based, anthracene-based, cyclic carbonyl-based, and triazole-based dyes.

(Content of each ingredient)
The content of dye A in the base material is preferably 0.01 to 30 parts by mass, and more preferably 0.02 to 25 parts by mass, based on 100 parts by mass of the resin.
The content of dye B in the substrate is preferably 0.01 to 30 parts by mass, and more preferably 0.02 to 25 parts by mass, based on 100 parts by mass of the resin.
The content of the UV dye in the substrate is preferably 0.01 to 30 parts by mass, and more preferably 0.02 to 25 parts by mass, based on 100 parts by mass of the resin.

(Base material composition)
The substrate may have a single layer structure or a multi-layer structure. The material of the substrate is not particularly limited and may be an organic material or an inorganic material as long as it is a transparent material that transmits visible light of 400 to 700 nm.

When the base material has a single layer structure, the base material is preferably a resin base material containing dye A and resin. Moreover, the resin base material can further contain dye B and a UV dye.
When the base material has a multilayer structure, the base material preferably has a structure in which a resin layer containing dye A and a resin is laminated on at least one main surface of the support. At this time, the support is preferably made of the above-mentioned transparent resin or transparent inorganic material. Moreover, the resin layer can further contain dye B and UV dye.

As the transparent inorganic material, glass or a crystalline material is preferable.
Examples of glass include absorbing glass (near infrared absorbing glass) containing copper ions in fluorophosphate glass or phosphate glass, soda lime glass, borosilicate glass, alkali-free glass, quartz glass, etc. As glass, absorbing glass is preferable depending on the purpose, and phosphate glass and fluorophosphate glass are preferable from the viewpoint of absorbing infrared light. When it is desired to capture a large amount of red light (600 to 700 nm), alkali glass, alkali-free glass, and quartz glass are preferable. Note that "phosphate glass" also includes silicophosphate glass, in which part of the glass skeleton is composed of _SiO2 .

The glass may be chemically strengthened glass obtained by exchanging alkali metal ions (e.g., Li ions, Na ions) with a small ionic radius present on the main surface of the glass sheet with alkali ions with a larger ionic radius (e.g., Na ions or K ions for Li ions, and K ions for Na ions) through ion exchange at a temperature below the glass transition point.

Examples of the crystal material include birefringent crystals such as quartz, lithium niobate, and sapphire.

As the support, inorganic materials are preferred from the viewpoint of shape stability related to the long-term reliability of optical properties, mechanical properties, etc., and handling properties during filter production, and glass and sapphire are particularly preferred.

When the base material is a resin base material with a single layer structure containing a transparent resin, UV dye, dye B, and dye A, it can be manufactured, for example, by the following method.

The resin substrate can be produced by melt extruding a transparent resin or a mixture of a transparent resin and optional components to form a film. Alternatively, the transparent resin and optional components, if necessary, are dissolved in a solvent to prepare a coating liquid, which is then applied to a desired thickness on a peelable substrate for producing the resin substrate, dried, and further cured as necessary, after which the resin substrate can be peeled off from the substrate.

The solvent used in the coating liquid may be a dispersion medium capable of stably dispersing or dissolving the transparent resin. The coating liquid may contain a surfactant to improve voids caused by minute bubbles, depressions caused by the adhesion of foreign matter, and repellency during the drying process. Furthermore, the coating liquid may be applied by, for example, a dip coating method, a cast coating method, a die coating method, or a spin coating method.

When the base material has a multilayer structure including a support and a resin layer containing UV dye, dye B, and dye A laminated on at least one main surface of the support, the thickness of the resin layer is 0. .3 to 15 μm is preferred. When the resin layer is composed of multiple layers, the total thickness of the resin layers is preferably 0.3 to 15 μm.

The resin layer can be formed by dissolving or dispersing the UV dye, dye B, dye A, resin or raw material components of the resin, and each component that is mixed as necessary in a solvent to prepare a coating liquid, applying this to a substrate, drying, and further curing as necessary. The substrate may be the support included in the present filter, or a peelable substrate used only when forming the resin layer. The solvent may be a dispersion medium in which the substrate can be stably dispersed, or a solvent in which the substrate can be dissolved.

The coating liquid may also contain a surfactant to improve voids caused by microbubbles, dents caused by adhesion of foreign matter, repellency during the drying process, and the like. Further, for applying the coating liquid, for example, a dip coating method, a cast coating method, a spin coating method, or the like can be used. A resin layer is formed by coating the above coating liquid onto a base material and then drying it. In addition, when the coating liquid contains a raw material component of a transparent resin, a curing treatment such as thermal curing or photocuring is further performed.

Further, the resin layer can be manufactured in the form of a film by extrusion molding, and this film may be laminated on another member and integrated by thermocompression bonding or the like. For example, this film may be adhered onto a support.

This filter may have one layer of resin, or may have two or more layers of resin. When this filter has two or more layers of resin, each layer may have the same or different configurations.

The shape of the base material is not particularly limited, and may be block-shaped, plate-shaped, or film-shaped.

When the substrate has a single layer structure, the thickness of the substrate is preferably 500 μm or less, more preferably 400 μm or less, from the viewpoint of reducing the height of the filter. When the substrate has a single layer structure, the thickness of the substrate is preferably 30 μm or more, more preferably 50 μm or more, from the viewpoint of handling during the process.

When the base material has a multilayer structure, the thickness of the base material is preferably 500 μm or less, more preferably 400 μm or less from the viewpoint of reducing the height of the present filter. Further, when the base material has a multilayer structure, the thickness of the base material is preferably 30 μm or more, more preferably 50 μm or more from the viewpoint of handling in the process.

<Dielectric multilayer film>
This filter can have a dielectric multilayer film. The dielectric multilayer film can be laminated as the outermost layer on at least one main surface side of the base material.

When the dielectric multilayer film is laminated as the outermost layer on both main surfaces of the base material, at least one of the dielectric multilayer films is designed as a near-infrared reflective layer (hereinafter also referred to as NIR reflective layer). It is preferable. The other dielectric multilayer film is preferably designed as an NIR reflective layer, a reflective layer having a reflective region other than the near-infrared region, or an antireflection layer.

If the substrate has a single-layer structure, it is preferable to form an NIR reflective layer on both sides of the substrate to prevent warping.

The NIR reflective layer is a dielectric multilayer film designed to block light in the near-infrared region. The NIR reflective layer has, for example, wavelength selectivity to transmit visible light and mainly reflect light in the near-infrared region other than the light-shielding region of the absorption layer. Note that the reflective region of the NIR reflective layer may include a light-blocking region in the near-infrared region of the absorbing layer. The NIR reflective layer is not limited to NIR reflective characteristics, and may be appropriately designed to further block light in a wavelength range other than the near-infrared region, for example, in the near-ultraviolet region.

The NIR reflective layer is composed of a dielectric multilayer film in which, for example, a low refractive index dielectric film (low refractive index film) and a high refractive index dielectric film (high refractive index film) are alternately laminated. The high refractive index film preferably has a refractive index of 1.6 or more, more preferably 2.2 to 2.5. Examples of materials for the high refractive index film include Ta ₂ O ₅ , TiO ₂ , and Nb ₂ O _5. Among these, TiO ₂ is preferred from the viewpoints of film formation, reproducibility in refractive index, stability, etc.

On the other hand, the low refractive index film preferably has a refractive index of less than 1.6, more preferably 1.45 or more and less than 1.55. Examples of materials for the low refractive index film include _{SiO2 and SiOxNy} . _SiO2 is preferred from the standpoints of reproducibility, stability, economy, etc. in film formation.

Furthermore, it is preferable that the NIR reflective layer has a steep change in transmittance in the boundary wavelength region between the transmission region and the light blocking region. For this purpose, the total number of laminated layers of the dielectric multilayer film constituting the reflective layer is preferably 15 layers or more, more preferably 25 layers or more, and even more preferably 30 layers or more. However, since a large total number of laminated layers can cause warping or an increase in film thickness, the total number of laminated layers is preferably 100 layers or less, more preferably 75 layers or less, and even more preferably 60 layers or less. Furthermore, the film thickness of the reflective layer as a whole is preferably 2 to 10 μm.

If the total number of layers and the film thickness of the dielectric multilayer film are within the above ranges, the NIR reflective layer satisfies the requirements for miniaturization and can suppress the incidence angle dependency while maintaining high productivity. In addition, the dielectric multilayer film can be formed using, for example, a vacuum film formation process such as a CVD method, a sputtering method, or a vacuum deposition method, or a wet film formation process such as a spray method or a dip method.

The NIR reflective layer may be one layer (one group of dielectric multilayer films) that provides the desired optical characteristics, or two layers that provide the desired optical characteristics. When there are two or more NIR reflective layers, each reflective layer may have the same or different configurations. When there are two or more NIR reflective layers, they are usually composed of multiple NIR reflective layers with different reflection bands. When two NIR reflective layers are provided, one may be a near-infrared reflective layer that blocks light in the short wavelength band of the near-infrared range, and the other may be a near-infrared/near-ultraviolet reflective layer that blocks light in both the long wavelength band of the near-infrared range and the near-ultraviolet range.

Examples of the antireflection layer include a dielectric multilayer film, an intermediate refractive index medium, and a moth-eye structure in which the refractive index gradually changes. Among these, dielectric multilayer films are preferred from the viewpoint of optical efficiency and productivity. The antireflection layer is obtained by alternately laminating dielectric films in the same way as the reflective layer.

Further, it is preferable that the dielectric multilayer film satisfies all of the following (v-1) to (v-4).
(v-1) IR50 at an incident angle of 0° is in the wavelength range of 650 to 800 nm.
(v-2) UV50 at an incident angle of 0° is in the wavelength range of 385 to 425 nm.
(v-3) In each of the spectral transmittance curves at incident angles of 0° and 30°, the average transmittance of light in the wavelength range of 435 to 650 nm is 88% or more.
(v-4) In each of the spectral transmittance curves at incident angles of 0° and 30°, the average transmittance of light in the wavelength range of 750 to 1000 nm is 10% or less.

Here, IR50 refers to wavelengths in the 650-800 nm wavelength range where the transmittance is 50%, and UV50 refers to wavelengths in the 385-425 nm wavelength range where the transmittance is 50%.

By using a dielectric multilayer film that satisfies the above (v-1) to (v-4) and a base material that has a resin layer that satisfies the above (iv-1) to (iv-6), it is possible to It is possible to obtain an optical filter that can sufficiently block the light and increase the transmittance of light in the blue band.

<Optical filter characteristics>
When the resin layer contains dye A and dye B, the present filter preferably satisfies all of the following (vi-1) to (vi-6).
(vi-1) The average transmittance at an incident angle of 0° over a wavelength range of 450 to 550 nm is 90% or more, and the minimum transmittance in this wavelength range is 88.5% or more.
(vi-2) The average transmittance at an incident angle of 0° for wavelengths of 600 to 700 nm is 25% or more.
(vi-3) The average transmittance at an incident angle of 0° for wavelengths of 710 to 1100 nm is 2% or less.
(vi-4) The average transmittance at an incident angle of 0° for wavelengths of 700 to 800 nm is 1.5% or less.
(vi-5) The maximum transmittance at an incident angle of 0° for wavelengths of 700 to 800 nm is 2% or less.
(vi-6) The absolute value of the difference between the transmittance for light having a wavelength of 600 to 700 nm on a spectral transmittance curve at an incident angle of 0° and the transmittance for light having a wavelength of 600 to 700 nm on a spectral transmittance curve at an incident angle of 30° is 7%/nm or less.

When all of the above (vi-1) to (vi-6) are satisfied, the present filter becomes an optical filter that can sufficiently block light in the near-infrared region and has increased transmittance of light in the blue band.

The average transmittance in the above (vi-1) is preferably 90.5% or more, more preferably 91.0% or more. The minimum transmittance in the above (vi-1) is preferably 88.6% or more, more preferably 88.7% or more.
The average transmittance in the above (vi-2) is preferably 30% or more, and more preferably 40% or more.
The average transmittance in the above (vi-3) is preferably 1.5% or less, and more preferably 1.0% or less.
The average transmittance in the above (vi-4) is preferably 1.3% or less, and more preferably 1.2% or less.
The maximum transmittance in the above (vi-5) is preferably 1.5% or less, more preferably 1.0% or less.
The absolute value of the difference in the above (vi-6) is preferably 5%/nm or less, more preferably 4%/nm or less.

[Imaging device]
The filter can be used, for example, in imaging devices such as digital still cameras.
When this filter is used in an imaging device, it has excellent color reproducibility.

The imaging device includes a solid-state imaging element, an imaging lens, and the present filter. The present filter can be used, for example, by being disposed between the imaging lens and the solid-state imaging element, or by being directly attached to the solid-state imaging element, imaging lens, etc. of the imaging device via an adhesive layer.

Next, the present invention will be explained in more detail with reference to Examples.
Note that Examples 1 to 6 are examples, and Examples 7 to 13 are comparative examples.

[Example 1]
The dye of Example 1 was synthesized by the following route.

<Step 1>
In a 1000 mL eggplant flask, mesityl iodide (100 g, 406.4 mmol), trimethylsilylacetylene (59.9 g, 609.5 mmol), tetrakis(triphenylphosphine)palladium(0) (6.1 g, 5.28 mmol), copper iodide (2.0 g, 10.6 mmol), and diethylamine (500 mL) were added. After degassing the flask, the atmosphere was replaced with nitrogen and the mixture was heated and stirred at 50° C. for 6 hours. After the reaction was completed, the solvent was distilled off under reduced pressure, water was added, and the mixture was extracted with dichloromethane. After dichloromethane was distilled off under reduced pressure, the mixture was purified by flash column chromatography (hexane) to obtain intermediate 1 (90.1 g, quant.).

<Step 2>
Intermediate 1 (90.1 g, 416.4 mmol) and methanol (600 mL) were added to a 1000 mL eggplant flask and cooled on ice. Potassium carbonate (167.9 g, 1214.8 mmol) was added thereto and stirred at room temperature under a nitrogen stream for 1 hour. After the reaction was completed, the reaction solution was filtered through Celite to remove potassium carbonate in the reaction system, and the filtrate was distilled under reduced pressure. Water was added to the obtained orange-yellow liquid and extracted with dichloromethane. After dichloromethane was distilled under reduced pressure, purification was performed by flash column chromatography (hexane) to obtain intermediate 2 (58.5 g, quant.).

<Step 3>
Intermediate 2 (22.0 g, 152.6 mmol) and tetrahydrofuran (125 mL) were added to a 1000 mL eggplant flask, and the mixture was stirred at -78°C under a nitrogen stream. n-Butyllithium (1.6 mol/L in hexane) (100 mL) was added using a dropping funnel, and the mixture was stirred at -78°C for 1 hour. Thereafter, ethyl formate (5.7 g, 76.3 mmol) dissolved in 20 mL of tetrahydrofuran was added using a dropping funnel, and the mixture was stirred at -78°C for 5 hours and at 0°C for 1.5 hours. After the reaction was completed, water was added to stop the reaction, and the mixture was extracted with dichloromethane. After dichloromethane was distilled off under reduced pressure, the obtained ocher solid was washed with hexane to obtain Intermediate 3 (13.4 g, yield 55.6%).

<Step 4>
Intermediate 3 (25.9 g, 83.7 mmol), dichloromethane (500 mL), and manganese oxide (36.4 g, 418.7 mmol) were added to a 1000 mL recovery flask, and the mixture was stirred at room temperature for 1 hour under a nitrogen stream. After the reaction was completed, the reaction solution was filtered to remove the manganese oxide, and the filtrate was distilled under reduced pressure. The obtained yellow powder was washed with hexane to obtain intermediate 4 (23.6 g, yield 91.8%).

<Step 5>
Intermediate 4 (21.9 g, 69.7 mmol), p-toluenesulfonic acid monohydrate (2.4 g, 13.9 mmol), methanol (230 mL), and toluene (230 mL) were added to a 1000 mL eggplant flask. Stirred at ℃ for 8 hours. Thereafter, the solvent was distilled off under reduced pressure, and methanol (280 mL) and concentrated hydrochloric acid (70 mL) were added thereto, followed by stirring at 70°C overnight. After the reaction was completed, the reaction solution was ice-cooled, water was added to stop the reaction, and then extracted with dichloromethane. After dichloromethane was distilled off under reduced pressure, toluene (350 mL) and trifluoromethanesulfonic acid (21.0 g, 139.9 mmol) were added, and the mixture was stirred at 100° C. for 2.5 hours. After the reaction was completed, the reaction solution was ice-cooled, water was added to stop the reaction, and the toluene layer was extracted. After toluene was distilled off under reduced pressure, the residue was purified by flash column chromatography (hexane/dichloromethane) to obtain a pink powder. The obtained pink powder was washed with hexane to obtain Intermediate 5 (15.5 g, yield 66.9%).

<Step 6>
Intermediate 5 (6.0 g, 18.0 mmol) and tetrahydrofuran (75 mL) were added to a 500 mL eggplant flask, stirred at 0°C, and methylmagnesium bromide (13% tetrahydrofuran solution) (49.7 g, 54.1 mmol) was added thereto. ) was added, and the mixture was heated and stirred at 70° C. for 1 hour under a nitrogen stream. After the reaction was completed, the reaction solution was poured little by little into a 10% aqueous hexafluorophosphoric acid solution (350 mL) at 0°C, and the reaction was stopped by stirring at 0°C for 10 minutes. This solution was extracted with dichloromethane, the dichloromethane layer was washed with water, and then dichloromethane was distilled off under reduced pressure. Intermediate 6 (8.2 g, yield 95.3%) was obtained by washing the obtained yellow powder with hexane.

<Step 7>
Intermediate 6 (1.75 g, 3.7 mmol), malonaldehyde dianilide hydrochloride (0.47 g, 1.84 mmol), sodium acetate (0.72 g, 8.82 mmol), acetic acid (15 mL) in a 200 mL eggplant flask. , acetic anhydride (15 mL) was added, and the mixture was heated and stirred at 80° C. for 45 minutes under a nitrogen stream. After the reaction was completed, the reaction solution was ice-cooled, water was added, and the reaction solution was filtered to recover a dark green powder. The recovered powder was purified by flash column chromatography (dichloromethane/ethyl acetate), and the resulting solid was washed with a solvent of hexane:ethyl acetate = 1:1 to obtain the dye of Example 1 (1.4 g). , yield 87.7%).

[Example 2]
The dye of Example 2 below was synthesized in the same manner as in Example 1, except that in step 6, the 10% aqueous hexafluorophosphoric acid solution was changed to a 10% aqueous tetrafluoroboric acid solution.

[Example 3]
A dye of Example 3 below was synthesized in the same manner as Example 1 except that the 10% aqueous hexafluorophosphoric acid solution in Step 6 was changed to a 10% aqueous bis(trifluoromethanesulfonyl)imide solution.

[Example 4]
The dye of Example 4 below was synthesized in the same manner as in Example 1, except that in Step 6, the 10% aqueous hexafluorophosphoric acid solution was changed to a 10% aqueous trifluoromethanesulfonic acid solution.

[Example 5]
The dye of Example 5 below was synthesized in the same manner as in Example 1, except that in step 6, the 10% aqueous hexafluorophosphoric acid solution was replaced with a 10% aqueous perrhenic acid solution.

[Example 6]
The dye of Example 6 was synthesized in the same manner as in Example 1, except that in Step 6, the 10% aqueous hexafluorophosphoric acid solution was replaced with a 10% aqueous perchloric acid solution.

[Example 7]
The dye of Example 7 below was synthesized with reference to International Publication No. 2017/135359.

[Example 8]
The dye of Example 8 below was synthesized with reference to Japanese Patent No. 6452247.

[Example 9]
The dye of Example 9 below was synthesized with reference to Japanese Patent No. 6452247.

[Example 10]
"FDR-026" manufactured by Yamada Chemical Co., Ltd. was used as the dye of Example 10.

[Example 11]
The dye in Example 11 was "S2137" manufactured by Few Chemicals, as shown below.

[Example 12]
The dye of Example 12 below was synthesized with reference to J. Am. Chem. Soc., 139, 2053 (2017) and Japanese Patent No. 1526450.

[Example 13]
The dye of Example 13 below was synthesized with reference to J. Am. Chem. Soc., 139, 2053 (2017) and J. Org. Chem., 68, 1804 (2003).

[Dye B]
The following dye B was synthesized with reference to International Publication No. 2016/133099.

<Test Example 1>
The dye was dissolved in dichloromethane, and the spectral transmittance curve was measured using a UV-Vis spectrophotometer (UV-Vis-Near Infrared Spectrophotometer UH4150 manufactured by Hitachi High-Tech Science Corporation).
The maximum absorption wavelength λmax(A), the maximum absorbance ε _A at wavelengths of 450 to 550 nm when the absorbance at the maximum absorption wavelength λmax(A) is taken as 1, the average absorbance ε _B at wavelengths of 450 to 470 nm, and the wavelength λ _ε0.002 at which the absorbance exceeds 0.002 in the wavelength range of 500 nm or less were measured, and 1/ε _A and 1/ε _B were calculated using the above-mentioned ε _A and ε _B.
Furthermore, the average value of the transmittance in the wavelength range of 650 to 700 nm was calculated when the transmittance at the maximum absorption wavelength was taken as 10%. The results are shown in Table 2.

From Table 2, it was found that the dyes of Examples 1 to 6 had sufficiently high transmittance in the blue band. Further, like the dyes of Examples 1 to 6, the dyes of Examples 12 and 13 having a pyrylium skeleton had a λmax (A) of less than 720 nm and had poor near-infrared shielding properties. On the other hand, the dyes of Examples 1 to 6 had λmax (A) in the range of 720 to 760 nm, and were found to have excellent near-infrared shielding properties.

<Test Example 2>
The dye was subjected to a solubility test in a resin solution.
In the solubility test, two types of resin solutions were used: a polyimide resin solution with a resin concentration of 8.5 mass % prepared by dissolving a polyimide resin ("C3G30G" (product name) manufactured by Mitsubishi Gas Chemical Company, Inc.) in a solution of γ-butyrolactone (GBL):cyclohexanone = 1:1 (mass ratio); and a cycloolefin resin solution with a resin concentration of 15 mass % prepared by dissolving a cycloolefin resin (manufactured by JSR Corporation, product name ARTON (registered trademark)) in cyclohexanone.

The dyes were added to the above two types of resin solutions, stirred at a temperature of 50° C. for 2 hours, and left to stand overnight, after which the presence or absence of dissolution was visually evaluated.
In addition, solubility was evaluated according to the following criteria. The results are shown in Table 3.

A: The solubility of the dye in the resin solution was more than 7.5% by mass.
B: The solubility of the dye in the resin solution was more than 3% by mass and 7.5% by mass or less.
C: The solubility of the dye in the resin solution was 3% by mass or less.

From Table 3, it was found that the dyes of Examples 1 to 6 had high solubility in the resin solution. Therefore, the use of the dyes of Examples 1 to 6 provides greater flexibility in resin selectivity and substrate thickness. Furthermore, the solubility of the dye of Example 13 having a pyrylium skeleton in a cycloolefin resin solution was worse than that of the dyes of Examples 1 to 6 which also had a pyrylium skeleton. From this, it was found that the dyes of Examples 1 to 6 had excellent resin solubility compared to conventional pyrylium skeleton dyes.

<Test Example 3>
Each dye was prepared by dissolving a polyimide resin (“C3G30G” (trade name) manufactured by Mitsubishi Gas Chemical Co., Ltd.) in a solution of γ-butyrolactone (GBL): cyclohexanone = 1:1 (mass ratio) at a resin concentration of 8.5 mass. % polyimide resin solution at the concentrations shown in Table 4, and stirred and dissolved at 50° C. for 2 hours to obtain a coating liquid. The obtained coating solution was applied to D263 glass manufactured by SCHOTT Co., Ltd. by a spin coating method to form a coating film (resin layer) having a thickness of approximately 1.0 μm.

In addition, only in Example 10, a coating film (resin layer) was formed so that the film thickness was approximately 2 μm. In addition, for the dyes in Examples 8 and 9, the solubility in the polyimide resin solution was low, so a coating film (resin layer) could not be formed.

The spectral transmittance curve of the obtained coating film (resin layer) was measured in the wavelength range of 350 to 1200 nm using an ultraviolet-visible spectrophotometer. From the measurement results, the maximum absorption wavelength λmax (pA) of the dye, the average internal transmittance and minimum internal transmittance in the wavelength range of 450 to 550 nm when the internal transmittance at λmax (pA) is set to 10%, the shortest wavelength value (Xa) at which the internal transmittance is 80% when the internal transmittance at λmax (pA) is set to 10%, and the longest wavelength value (Xb) at which the internal transmittance is 80%, and the absolute value of the difference between them, |Xa-Xb|, were calculated.

The results are shown in Table 4 together with the dye concentration relative to the resin in the coating film (resin layer). Note that the spectral characteristics shown in Table 4 were evaluated based on internal transmittance in order to avoid the influence of reflection at the air interface and glass interface.
Internal transmittance={actually measured transmittance/(100-actually measured reflectance)}×100

From Table 4, it was found that the dyes of Examples 1 to 6 had excellent near-infrared light blocking properties and sufficiently high transmittance in the blue band.

<Test Example 4>
Each pigment was mixed with a 15% by mass cyclohexanone solution of a cycloolefin resin (ARTON) at the concentrations shown in Table 5, and the mixture was stirred and dissolved at 50° C. for 2 hours to obtain a coating liquid. The obtained coating solution was applied to D263 glass manufactured by SCHOTT Co., Ltd. by a spin coating method to form a coating film (resin layer) having a thickness of approximately 1.0 μm.

The dyes in Examples 8 and 9 had low solubility in the ARTON resin solution, so a coating film (resin layer) could not be formed.

The spectral transmittance curve of the obtained coating film (resin layer) was measured in the wavelength range of 350 to 1200 nm using an ultraviolet-visible spectrophotometer. From the measurement results, the maximum absorption wavelength λmax (pA) of the dye, the average internal transmittance and minimum internal transmittance in the wavelength range of 450 to 550 nm when the internal transmittance at λmax (pA) is set to 10%, the shortest wavelength value (Xa) at which the internal transmittance is 80% when the internal transmittance at λmax (pA) is set to 10%, and the longest wavelength value (Xb) at which the internal transmittance is 80%, and the absolute value of the difference between them, |Xa-Xb|, were calculated.

The results are shown in Table 5 together with the dye concentration relative to the resin in the coating film (resin layer). Note that the spectral characteristics shown in Table 5 were evaluated based on internal transmittance in order to avoid the influence of reflection at the air interface and glass interface.
Internal transmittance={actually measured transmittance/(100-actually measured reflectance)}×100

Table 5 shows that the dyes of Examples 1 and 3 have excellent near-infrared light blocking properties and sufficiently high transmittance in the blue band, even when cycloolefin resin is used.

<Test Example 5>
Prepare dye B in the same manner as Test Example 3 by dissolving polyimide resin (“C3G30G” (trade name) manufactured by Mitsubishi Gas Chemical Co., Ltd.) in a solution of γ-butyrolactone (GBL): cyclohexanone = 1:1 (mass ratio). A coating liquid was obtained by mixing a dye concentration of 7.5 mass% with a polyimide resin solution having a resin concentration of 8.5 mass%, and stirring and dissolving at 50° C. for 2 hours. The obtained coating solution was applied to D263 glass manufactured by SCHOTT Co., Ltd. by a spin coating method to form a coating film (resin layer) having a thickness of approximately 1.0 μm.

The spectral transmittance curve of the resulting coating film (resin layer) was measured in the wavelength range of 350 to 1200 nm using a UV-Vis spectrophotometer.

Based on the measurement data for dye B obtained above and the measurement data for the polyimide obtained in Test Example 3, the data was normalized so that the film thickness of each coating film (resin layer) was 1 μm, and the spectral characteristics of the internal transmittance in the wavelength range of 350 to 1200 nm of composite coating films 1 to 6 obtained when the dyes and dye B of the examples and comparative examples were added in the amounts listed in Table 6 were estimated.

From the obtained spectral characteristic data, the shortest wavelength (Ya) at which the internal transmittance is 50%, the longest wavelength (Yb) at which the internal transmittance is 50%, the absolute value of the difference between them |Ya-Yb|, the internal transmittance at a wavelength of 750 nm, the average internal transmittance at wavelengths of 730-780 nm, the average and minimum internal transmittance at wavelengths of 680-740 nm, and the average and minimum internal transmittance at wavelengths of 450-550 nm were calculated. The results are shown in Table 6.

The spectral transmittance curves of composite coating films 3 and 4 are shown in Figure 2, and an enlarged view of the curves is shown in Figure 3.

From Table 6 and FIGS. 2 and 3, it was found that the composite coating films using the dyes of Examples 1 to 3 had sufficiently high transmittance in the blue band. In addition, the composite coating films using the dyes of Examples 1 to 3 have higher minimum transmittance especially in the blue band than the composite coating films using the dyes of Examples 7, 10, and 11. It becomes possible to increase the transmittance.

<Test Example 6>
A reflective layer with a thickness of 6 μm was designed in which TiO ₂ films and SiO ₂ films were alternately laminated. The reflective layer was simulated using the number of dielectric multilayer films, the thickness of the TiO ₂ film, and the thickness of the SiO ₂ film as parameters, and was designed to satisfy the following conditions in each spectral transmittance curve at an incident angle of 0° and 30°. Designed.

1. It has a wavelength (IR50) at which the transmittance is 50% in the wavelength range of 650 to 800 nm.
2. It has a wavelength (UV50) at which the transmittance is 50% in the wavelength range of 385 to 425 nm.
3. In each of the spectral transmittance curves at angles of incidence of 0° and 30°, the average transmittance of light in the wavelength range of 435 to 650 nm is 88% or more.
4. In each of the spectral transmittance curves at angles of incidence of 0° and 30°, the average transmittance of light in the wavelength range of 750 to 1000 nm is 10% or less.

Table 7 shows the spectral data of the reflective layer designed based on the above.

The internal transmittance in the wavelength range of 350 to 1200 nm of Composite Coating Films 1 to 4 and Composite Coating Film 6 obtained in Test Example 5 was multiplied by the transmittance data of the reflective layer designed above at each wavelength. Combined. By doing so, the spectral characteristics of an optical filter in which a composite coating film was formed on one side of a D263 glass substrate and a 6 μm thick reflective layer was formed on the other side were estimated. The results are shown in Table 8.

Note that the transmittance values listed in Table 8 are values at an incident angle of 0°.

Table 8 shows that the optical filters using the dyes of Examples 1 to 3 have sufficiently high transmittance in the blue band.

<Test Example 7>
The dye of Example 1, the dye of Example 2, and the dye of Example 12 were respectively mixed with polyimide resin (“C3G30G” (trade name) manufactured by Mitsubishi Gas Chemical Co., Ltd.) and γ-butyrolactone (GBL): cyclohexanone = 1:1 (mass ratio). The mixture was mixed with a polyimide resin solution having a resin concentration of 8.5% by mass prepared by dissolving it in a solution shown in Table 9, and the mixture was stirred and dissolved at 50°C for 2 hours to obtain a coating liquid. The obtained coating solution was applied to D263 glass manufactured by SCHOTT Co., Ltd. by a spin coating method to form a coating film (resin layer) having a thickness of approximately 1.0 μm. Thereafter, a TiO ₂ film and a SiO ₂ film were alternately laminated on the surface of the coating film (resin layer) to form an antireflection layer, thereby obtaining an optical filter for light resistance evaluation. The following light resistance test was conducted on the produced optical filter for evaluation of light resistance.

(Lightfastness test)
Using a xenon lamp, the illuminance at wavelengths of 300 to 400 nm was adjusted to 75 W/ ^m2 , and light was irradiated from the antireflection layer side of the optical filter for a total of 80 hours. Before and after irradiation, a spectral transmittance curve was measured at an incident angle of 0° using a UV-Visible spectrophotometer, and the absorbance at the maximum absorption wavelength before and after irradiation was determined. The dye residual rate was calculated using the following formula and evaluated based on the following criteria. The results are shown in Table 9.

Pigment remaining rate (%) = (absorbance at maximum absorption wavelength after irradiation) / (absorbance at maximum absorption wavelength before irradiation) x 100

A: The pigment remaining rate was more than 85%.
B: The pigment residual rate was more than 70% and 85% or less.
C: The residual dye rate was 70% or less.

From Table 9, it was found that the optical filters using the dyes of Examples 1 and 2 had excellent light resistance. This shows that the dyes of Examples 1 and 2 are also superior in light resistance compared to conventional pyrylium skeleton dyes.

10 Optical filter 11 Support body 12 Resin layer

Claims (11)

An optical filter comprising a substrate,
The substrate has a resin layer,
the resin layer contains a near infrared absorbing dye A and a resin,
The near-infrared absorbing dye A is a dye compound represented by the following formula (2) ,

The symbols in formula (2) are as follows.
X ⁻ is a monovalent anion species.
R ₁ is a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms which may have a substituent, an araryl group having 7 to 13 carbon atoms which may have a substituent, or --NR ₉ R ₁₀ .
R ₂ to R ₅ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms which may have a substituent, or an araryl group having 7 to 13 carbon atoms which may have a substituent. Two adjacent groups of R ₂ to R ₅ may be bonded to each other to form a 5- to 8-membered ring.
R ₉ and R ₁₀ are each independently an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms which may have a substituent, or a carbonyl group having 1 to 12 carbon atoms which may have a substituent.
R ₁₁ and R ₁₂ each independently represent an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms.
R ₁₃ is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. The optical filter according to claim 1, wherein the near-infrared absorbing dye A further satisfies the following (i-4) in a spectral transmittance curve at wavelengths of 350 to 1200 nm measured after dissolving in dichloromethane:
(i-4) When the absorbance at the absorption maximum wavelength λmax(A) of the near infrared absorbing dye A is set to 1, a wavelength _λε0.002 at which the absorbance exceeds 0.002 in a wavelength range of 500 nm or less satisfies the following condition:
λ ε _0.002 ≦ 455 nm 3. The optical filter according to claim 1, wherein the near-infrared absorbing dye A further satisfies the following (i-5) in a spectral transmittance curve at wavelengths of 350 to 1200 nm measured after dissolving in dichloromethane:
(i-5) When the transmittance at the absorption maximum wavelength λmax(A) of the near infrared absorbing dye A is set to 10%, the average transmittance in the wavelength range of 650 to 700 nm is 60% or more. The resin is a transparent resin,
4. The optical filter according to claim 1, wherein the transparent resin is at least one resin selected from the group consisting of cycloolefin polymers, cycloolefin copolymers, polyimide resins, polycarbonate resins, polyethylene terephthalate , polyester resins, polyolefin resins, acrylic resins, urethane resins, vinyl chloride resins, fluororesins, polyvinyl butyral resins, and polyvinyl alcohol resins. The optical filter according to any one of claims 1 to 4 , wherein the near-infrared absorbing dye A satisfies the following (ii-1) and (ii-2) in a resin layer containing only the near-infrared absorbing dye A and the resin:
(ii-1) When the internal transmittance of the absorption maximum wavelength λmax (pA) of the near infrared absorbing dye A is set to 10%, the average internal transmittance at wavelengths of 450 to 550 nm is 97.0% or more, and the minimum internal transmittance at wavelengths of 450 to 550 nm is 96.5% or more.
(ii-2) When the internal transmittance of the absorption maximum wavelength λmax (pA) of the near infrared absorbing dye A is set to 10%, the absolute value |Xa-Xb| of the difference between the shortest wavelength value (Xa) at which the internal transmittance becomes 80% and the longest wavelength value (Xb) at which the internal transmittance becomes 80% is 140 nm or more. The resin layer further contains near-infrared absorbing dye B,
Any one of claims 1 to 5 , wherein the near-infrared absorbing dye B satisfies the following (iii-1) and (iii-2) in a spectral transmittance curve at a wavelength of 350 to 1200 nm measured after being dissolved in dichloromethane. The optical filter according to item 1.
(iii-1) The absorption maximum wavelength λmax (B) of the near-infrared absorbing dye B is in the wavelength range of 670 to 730 nm.
(iii-2) The maximum absorption wavelength λmax (B) and the maximum absorption wavelength λmax (A) of the near-infrared absorbing dye A satisfy the following conditions.
λmax(B)<λmax(A) The optical filter according to claim 6 , wherein the resin layer satisfies all of the following (iv-1) to (iv-6).
(iv-1) Absolute value of the difference between the shortest wavelength value (Ya) at which the internal transmittance is 50% and the longest wavelength value (Yb) at which the internal transmittance is 50% | Ya - Yb | is in the range of 100 to 150 nm.
(iv-2) The shortest wavelength value (Ya) at which the internal transmittance is 50% is in the range of 630 to 680 nm.
(iv-3) Internal transmittance at a wavelength of 750 nm is 30% or less.
(iv-4) The average value of internal transmittance at a wavelength of 730 to 780 nm is 40% or less.
(iv-5) The average value of the internal transmittance at a wavelength of 680 to 740 nm is 10% or less, and the minimum value of the internal transmittance is 5% or less.
(iv-6) The average value of internal transmittance at a wavelength of 450 to 550 nm is 97% or more, and the minimum value of the internal transmittance is 94% or more. The optical filter according to claim 6 or 7 , which satisfies all of the following (vi-1) to (vi-6):
(vi-1) The average transmittance at an incident angle of 0° for wavelengths of 450 to 550 nm is 90% or more, and the minimum transmittance is 88.5% or more.
(vi-2) The average transmittance at an incident angle of 0° for wavelengths of 600 to 700 nm is 25% or more.
(vi-3) The average transmittance at an incident angle of 0° for wavelengths of 710 to 1100 nm is 2% or less.
(vi-4) The average transmittance at an incident angle of 0° for wavelengths of 700 to 800 nm is 1.5% or less.
(vi-5) The maximum transmittance at an incident angle of 0° for wavelengths of 700 to 800 nm is 2% or less.
(vi-6) The absolute value of the difference between the transmittance for light having a wavelength of 600 to 700 nm on a spectral transmittance curve at an incident angle of 0° and the transmittance for light having a wavelength of 600 to 700 nm on a spectral transmittance curve at an incident angle of 30° is 7%/nm or less. The base material has the resin layer and a support,
The optical filter according to any one of claims 1 to 8 , wherein the resin layer is laminated on at least one main surface of the support. An imaging device comprising the optical filter according to claim 1 . A dye compound represented by the following formula (2).

The symbols in formula (2) are as follows.
X ⁻ is a monovalent anion species.
R ₁ is a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms which may have a substituent, or a aryl group having 7 to 13 carbon atoms which may have a substituent. It is an aralyl group, or -NR ₉ R ₁₀ .
R ₂ to R ₅ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or a cycloalkyl group having 6 to 12 carbon atoms which may have a substituent. It is an aryl group or an aralyl group having 7 to 13 carbon atoms which may have a substituent. Two adjacent R ₂ to R ₅ may be linked to each other to form a 5- to 8-membered ring.
R ₉ and R ₁₀ are each independently an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms which may have a substituent, or an aryl group having 1 to 12 carbon atoms which may have a substituent. 12 carbonyl groups.
R ₁₁ and R ₁₂ are each independently an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms.
R ₁₃ is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.

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