JP7059729B2 - Optical filters, near-infrared absorbing dyes and imaging devices - Google Patents

Description

The present invention relates to an optical filter that transmits visible light and shields near-infrared light, a near-infrared absorbing dye that is suitably used for the optical filter, and an image pickup apparatus provided with the optical filter.

In an image pickup device using a solid-state image sensor, in order to reproduce color tones well and obtain a clear image, light in the visible region (hereinafter also referred to as "visible light") is transmitted and light in the near infrared region (hereinafter referred to as "near red"). An optical filter that shields (also called "external light") is used. In the optical filter, a configuration is known in which various absorption layers and reflection layers are appropriately combined in order to sufficiently shield the entire region of the near-infrared light wavelength region where shielding is required.

For example, a phosphate-based glass or a glass obtained by adding CuO or the like to a phosphate-based glass has absorption in a wavelength range of approximately 800 to 1050 nm, and is therefore used as an absorption layer in an optical filter. However, such absorption-type glass is expensive, and there is a concern that it cannot sufficiently meet the recent demands for miniaturization and thinning of image pickup devices in terms of absorbency.

Therefore, instead of or in combination with the absorption-type glass, an absorption layer in which a dye having an absorption wavelength is uniformly dispersed in a transparent resin in the absorption wavelength region of the absorption-type glass has been used. .. Specific examples of the optical filter using such a dye include a diimonium-based dye (for example, Patent Document 1), a chromon-type squarylium-based dye (for example, Patent Documents 2 and 3), and a phthalocyanine-based dye (for example, Patent Document 1). 4), an optical filter using a naphthalene-based dye (for example, Patent Document 5) and the like is known. Further, for example, an optical filter (for example, Patent Document 6) in which a squarylium-based dye, a cyanine-based dye, a phthalocyanine-based dye, and the like are combined is known.

Japanese Unexamined Patent Publication No. 2010-266870 Japanese Unexamined Patent Publication No. 2016-142891 Japanese Patent No. 5583927 Japanese Patent No. 5909936 Japanese Patent No. 4596019 International Publication No. 2013/054864

However, none of the above optical filters can achieve both high transparency of visible light and shielding of near-infrared light in the wavelength range corresponding to absorption-type glass at a high level.

The present invention is an optical filter capable of achieving near-infrared light shielding in the wavelength range corresponding to absorption-type glass at a high level in terms of near-infrared light shielding while maintaining good visible light transmission. It is an object of the present invention to provide a dye preferably used for the optical filter and an image pickup apparatus using the optical filter and having excellent color reproducibility.

The optical filter according to one aspect of the present invention has an absorption layer containing a dye (A) represented by the following formula (A1) or (A2).

However, the symbols in the formulas (A1) and (A2) are as follows.
R ¹⁰¹ to R ¹⁰⁹ and R ¹¹¹ to R ¹¹⁷ may each independently have a hydrogen atom, a halogen atom, a sulfo group, a hydroxyl group, a cyano group, a nitro group, a carboxy group, a phosphoric acid group, and a substituent. An alkyl group having 1 to 10 carbon atoms, an alkoxy group or an acyloxy group, or -NR ¹²⁸ R ¹²⁹ (R ¹²⁸ and R ¹²⁹ may each independently have a hydrogen atom or a substituent having 1 to 10 carbon atoms. It is an alkyl group of 15.). In R ¹⁰² to R ¹⁰⁷ and R ¹¹² to R ¹¹⁷ , two adjacent two may be connected to each other to form a ring having 5 to 8 members.
Equations (A1) and ( ^A2 ) optionally have ^Z1 and Z2. Z ¹ and Z ² are 5-membered or 6-membered rings.
X ⁻ indicates a monovalent anion, and m1 and m2 indicate the number of X ⁻ , which is 0 or 1.
When m1 and m2 are 0, R ¹¹⁰ and R ¹¹⁸ are monovalent anionic groups.
When m1 and m2 are 1, R ¹¹⁰ and R ¹¹⁸ are hydrogen atoms, halogen atoms, or -Y ⁵ -R ¹³⁰ (Y ⁵ is a single bond, ether bond (-O-), sulfonyl bond (-SO ₂ ). -), Ester bond (-C (= O) -O- or -OC (= O)-) or ureido bond (-NH-C (= O) -NH-), where ^R130 is substituted. It is an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 30 carbon atoms which may have a group).

The present invention also provides a dye represented by the formula (A1) or (A2).
The present invention also provides an image pickup apparatus equipped with the optical filter of the present invention.

According to the present invention, while maintaining good transparency of visible light, in the shielding property of near-infrared light, the wavelength range corresponding to the absorbent glass, particularly the near-infrared wavelength range of 800 to 1050 nm. It is possible to provide an optical filter capable of achieving a high level of light shielding. Further, according to the present invention, it is possible to provide a dye (A) preferably used for the optical filter. Further, according to the present invention, it is possible to provide an image pickup device having excellent color reproducibility using the optical filter.

It is sectional drawing which shows typically the example of the optical filter of an embodiment. It is sectional drawing which shows typically another example of the optical filter of an embodiment. It is sectional drawing which shows typically another example of the optical filter of an embodiment. It is sectional drawing which shows typically another example of the optical filter of an embodiment. It is sectional drawing which shows typically another example of the optical filter of an embodiment. It is sectional drawing which shows typically another example of the optical filter of an embodiment. It is sectional drawing which shows typically another example of the optical filter of an embodiment.

Hereinafter, embodiments of the present invention will be described.
In the present specification, the near-infrared absorbing dye may be abbreviated as "NIR dye" and the ultraviolet absorbing dye may be abbreviated as "UV dye".
In the present specification, for example, the compound represented by the formula (A1) is referred to as a compound (A1). The same applies to compounds represented by other formulas. When the compound (A1) is a dye, the compound (A1) is also referred to as a dye (A1), and the same applies to other compounds. Further, for example, the group represented by the formula (1x) is also described as a group (1x), and the same applies to the groups represented by other formulas.

In the present specification, for a specific wavelength range, for example, a transmittance of 90% or more means that the transmittance does not fall below 90% in the entire wavelength range, and similarly, a transmittance of, for example, 1% or less means. It means that the transmittance does not exceed 1% in the entire wavelength region.
In the present specification, "-" representing a numerical range includes an upper and lower limit.

In the present specification, the mass absorption coefficient [/ cm · mass%] when the dye is contained in the resin can be calculated as follows. That is, for the resin layer (measurement sample) containing the dye in the resin, the internal transmittance T [%] (= measured transmittance [%] / (100-measured reflectance [%]) × 100 [%]) is determined. Calculate and calculate the reflectance coefficient by -log ₁₀ (T / 100). When the dye is contained in the resin, the value obtained by dividing the obtained absorption coefficient by the film thickness [cm] of the resin layer used as the measurement sample and the content [mass%] of the dye with respect to the resin in the resin layer is used. It is the mass absorption coefficient. In the present specification, the mass absorption coefficient when the dye is contained in the resin is calculated in the wavelength range of 350 to 1200 nm, and the maximum value of the mass absorption coefficient in the above range is referred to as the maximum mass absorption coefficient.

<Optical filter>
The optical filter of one embodiment of the present invention (hereinafter, also referred to as “the present filter”) has an absorption layer containing the dye (A) represented by the above formula (A1) or (A2). The absorption layer preferably contains the dye (A) and the transparent resin.

In addition to the absorption layer, the filter may further have a reflection layer made of a dielectric multilayer film. In the following description, the "reflective layer" refers to a reflective layer made of a dielectric multilayer film.

The filter may further have a transparent substrate. In this case, the absorption layer is provided on the main surface of the transparent substrate. When the filter has a transparent substrate and an absorption layer and a reflection layer, the absorption layer and the reflection layer are provided on the main surface of the transparent substrate. The present filter may have the absorption layer and the reflection layer on the same main surface of the transparent substrate, or may have the absorption layer and the reflection layer on different main surfaces. When the absorption layer and the reflection layer are provided on the same main surface, the stacking order thereof is not particularly limited.

The filter may also have other functional layers. Examples of the other functional layer include an antireflection layer that suppresses the loss of transmittance of visible light. In particular, when the absorption layer has the outermost surface structure, a visible light transmittance loss due to reflection occurs at the interface between the absorption layer and air, so it is preferable to provide an antireflection layer on the absorption layer.

Next, a configuration example of this filter will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an optical filter 10A composed of an absorption layer 11. The absorption layer 11 can be composed of a layer containing the dye (A) and the transparent resin. In the optical filter 10A, the absorption layer 11 may take the form of a film or a substrate.

FIG. 2 is a configuration example of an optical filter 10B having a reflection layer 12 on one main surface of the absorption layer 11. In the optical filter 10B, the absorption layer 11 can be composed of a layer containing the dye (A) and the transparent resin. The phrase "providing the reflective layer 12 on one main surface (upper) of the absorbent layer 11" is not limited to the case where the reflective layer 12 is provided in contact with the absorbent layer 11, and the absorbent layer 11 and the reflective layer 12 are used. The same applies to the following configurations, including the case where another functional layer is provided between the two.

3 and 4 are cross-sectional views schematically showing an example of an optical filter of an embodiment having a transparent substrate and an absorption layer, and having a transparent substrate, an absorption layer and a reflection layer, respectively. The optical filter 10C has an absorption layer 11 arranged on one main surface of the transparent substrate 13 and the transparent substrate 13. The optical filter 10D has an absorption layer 11 arranged on one main surface of the transparent substrate 13 and the transparent substrate 13, and a reflection layer 12 provided on the other main surface of the transparent substrate 13. In the optical filters 10C and 10D, the absorption layer 11 can be composed of a layer containing the dye (A) and the transparent resin.

FIG. 5 shows an optical filter 10E having an absorption layer 11 on one main surface of the transparent substrate 13 and reflective layers 12a and 12b on the other main surface of the transparent substrate 13 and on the main surface of the absorption layer 11. This is a configuration example. FIG. 6 is a configuration example of an optical filter 10F provided with absorption layers 11a and 11b on both main surfaces of the transparent substrate 13 and further provided with reflection layers 12a and 12b on the main surfaces of the absorption layers 11a and 11b.

In FIGS. 5 and 6, the two reflective layers 12a and 12b to be combined may be the same or different. For example, the reflective layers 12a and 12b have a property of reflecting ultraviolet light and near-infrared light and transmitting visible light, and the reflective layer 12a reflects ultraviolet light and light in the first near-infrared region. The reflective layer 12b may be configured to reflect the ultraviolet light and the light in the second near-infrared region.

Further, in FIG. 6, the two absorption layers 11a and 11b may be the same or different. When the absorption layers 11a and 11b are different, for example, the absorption layers 11a and 11b may be a combination of a near-infrared absorbing layer and an ultraviolet absorbing layer, or may be a combination of an ultraviolet absorbing layer and a near-infrared absorbing layer, respectively.

FIG. 7 is a configuration example of the optical filter 10G provided with the antireflection layer 14 on the main surface of the absorption layer 11 of the optical filter 10D shown in FIG. The antireflection layer 14 may be configured to cover not only the outermost surface of the absorption layer 11 but also the entire side surface of the absorption layer 11. In that case, the moisture-proof effect of the absorption layer 11 can be enhanced.

Hereinafter, the absorption layer, the reflection layer, the transparent substrate, and the antireflection layer will be described.
(Absorption layer)
The absorption layer contains the dye (A). The dye (A) is a dye (A) represented by the formula (A1) or (A2). The dye (A) represented by the formula (A1) or (A2) is a novel compound synthesized by the present inventor.

[Dye (A)]
The dye (A) is represented by the following formula (A1) or (A2). The dye (A) may be a dye (A1) or a dye (A2).

However, the symbols in the formulas (A1) and (A2) are as follows.
R ¹⁰¹ to R ¹⁰⁹ and R ¹¹¹ to R ¹¹⁷ may each independently have a hydrogen atom, a halogen atom, a sulfo group, a hydroxyl group, a cyano group, a nitro group, a carboxy group, a phosphoric acid group, and a substituent. An alkyl group having 1 to 10 carbon atoms, an alkoxy group or an acyloxy group, or -NR ¹²⁸ R ¹²⁹ (R ¹²⁸ and R ¹²⁹ may each independently have a hydrogen atom or a substituent having 1 to 10 carbon atoms. It is an alkyl group of 15.).

The substituent in the alkyl group having 1 to 10 carbon atoms which may have a substituent, an alkoxy group or an acyloxy group, and the alkyl group having 1 to 15 carbon atoms which may have a substituent may be a halogen atom or a carbon number. Examples thereof include 1 to 10 alkoxy groups.

Here, unless otherwise specified, the alkyl group may be linear, branched, cyclic, or a combination of these structures. The same applies to the alkyl group of the alkoxy group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom and a chlorine atom are preferable.

R ¹⁰¹ , R ¹⁰⁸ , R ¹⁰⁹ and R ¹¹¹ each have a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group or an acyloxy group independently from the viewpoint of ease of synthesis and the like. A hydrogen atom is preferable, and a hydrogen atom is particularly preferable.

R ¹⁰² to R ¹⁰⁷ and R ¹¹² to R ¹¹⁷ are independently hydrogen atoms, halogen atoms, hydroxyl groups, alkyl groups having 1 to 10 carbon atoms, alkoxy groups or acyloxy groups, and -NR ¹²⁸ R ¹²⁹ (R ¹²⁸ and R 129). R ¹²⁹ is preferably an alkyl group which may independently have a hydrogen atom and a substituent having 1 to 15 carbon atoms (a halogen atom or an alkoxy group having 1 to 10 carbon atoms). From the viewpoint of ease of synthesis and the like, these are preferably hydrogen atoms or alkyl groups having 1 to 10 carbon atoms independently of each other.

At least one of R ¹⁰² to R ¹⁰⁷ and R ¹¹² to R ¹¹⁷ is preferably -NR ¹²⁸ R ¹²⁹ from the viewpoint of easily increasing the molar extinction coefficient. In that case, -NR ¹²⁸ R ¹²⁹ is ^an alkyl group having 1 to 15 carbon atoms, one of which may have a hydrogen atom or a substituent, and the other may have a substituent ^. An alkylamino group, which is an alkyl group having 1 to 15 carbon atoms, is preferable. The alkylamino group preferably has both R ¹²⁸ and R ¹²⁹ as an alkyl group having 1 to 15 carbon atoms, and the alkyl group is linear or branched from the viewpoint of solubility in a transparent resin or a solvent. Chain form is preferable.

It is preferable that R ¹⁰⁴ in R ¹⁰² to R ¹⁰⁷ and R ¹¹⁴ in R ¹¹² to R ¹¹⁷ are the above-mentioned alkylamino groups, respectively, from the viewpoint of ease of synthesis and the like.

R ¹⁰⁶ and R ¹⁰⁷ , R ¹¹⁶ and R ¹¹⁷ are preferably alkyl groups having 1 to 10 carbon atoms from the viewpoint of solubility in transparent resins and solvents, and secondary or tertiary branched alkyls having 10 or less carbon atoms. Groups are more preferred, and tertiary butyl groups, isopropyl groups and isobutyl groups are even more preferred.

In R ¹⁰² to R ¹⁰⁷ and R ¹¹² to R ¹¹⁷ , two adjacent two may be connected to each other to form a ring having 5 to 8 members. The ring may be aliphatic or aromatic. For example, R ¹⁰² and R ¹⁰³ , R ¹¹² and R ¹¹³ may be linked together to form an aromatic 6-membered ring.

Equations (A1) and ( ^A2 ) optionally have ^Z1 and Z2. Z ¹ and Z ² are 5-membered or 6-membered rings. When the dye (A1) and the dye (A2) have Z ¹ and Z ² , respectively, they are preferable in terms of durability. The hydrogen atom bonded to the carbon atom constituting Z ¹ and Z ² may be substituted with an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms. Structurally, compound (A1) tends to have ^a structure having Z1.

In the present specification, unless otherwise specified, the aryl group is bonded via a carbon atom constituting an aromatic ring of an aromatic compound, for example, a benzene ring, a naphthalene ring, a biphenyl, a furan ring, a thiophene ring, a pyrrole ring, or the like. Refers to the group to be used.

X ⁻ indicates a monovalent anion, and m1 and m2 indicate the number of X ⁻ , which is 0 or 1. Examples of X ⁻ include I ⁻ , BF ^4- , PF ₆ ⁻ , ClO _4- ^, anions represented by the formulas (X1) and (X2), and preferably BF 4-, PF 6 −, and anions (Preferably, BF ^4- , PF ₆ ⁻ , and anions. X1).

When m1 and m2 are 1, R ¹¹⁰ and R ¹¹⁸ are hydrogen atoms, halogen atoms, or -Y ⁵ -R ¹³⁰ (Y ⁵ is a single bond, ether bond (-O-), sulfonyl bond (-SO ₂ ). -), Ester bond (-C (= O) -O- or -OC (= O)-) or ureido bond (-NH-C (= O) -NH-), where ^R130 is substituted. It is an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 30 carbon atoms which may have a group). Examples of the substituent include a halogen atom or an alkoxy group having 1 to 10 carbon atoms.

R ¹¹⁰ and R ¹¹⁸ are preferably a hydrogen atom, a halogen atom, and ^{—Y5 - R130} in which Y5 is a single bond, and are substituted with a hydrogen atom, a chlorine atom, an alkyl group having 1 to 10 carbon atoms, and a halogen atom. A aryl group having 6 to 10 carbon atoms may be more preferable.

When m1 and m2 are 0, R ¹¹⁰ and R ¹¹⁸ are monovalent anionic groups. Examples of the monovalent anionic group include the anionic group represented by any of the following (B1) to (B6).

In the formulas (B1) to (B6), R ²⁰¹ to R ²¹⁴ each independently have 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.

In the dye (A1) and the dye (A2), 1 is preferable for m1 and m2 from the viewpoint of ease of synthesis.

In the formula (A1) and the formula (A2), as the compound when m1 and m2 are 1, more specifically, the atoms or groups bonded to each skeleton are shown in Tables 1 and 2 below, respectively. Examples include compounds. In all the compounds shown in Table 1, R ¹⁰¹ to R ¹⁰⁷ are all the same on the left and right sides of the formula. In all the compounds shown in Table 2, R ¹¹¹ to R ¹¹⁷ are the same on the left and right sides of the equation.

Although X ^- is not shown in Tables 1 and 2, X ^- is preferably BF ^4- , PF _6- ^or anion (X1) in any of the compounds. In the dye (A1-1) ^, the case where X- is BF ^4- is the dye (A1-1B), the case of PF _6- is the dye (A1-1P), ^and the case of the anion (X1) is the dye (A1-1X1). Is shown. The same applies to the other dyes shown in Tables 1 and 2. In Tables 1 and 2, Ph represents a phenyl group or a 1,4-phenylene group. -NC ₄ H ₉ represents a linear butyl group.

In the columns of Z ¹ and Z ² , "-" indicates that Z ¹ and Z ² are not present, and "-(CH ₂ ) _2- " indicates that Z ¹ and Z ² are 5-membered rings. "-(CH ₂ ) _3- " indicates that Z ¹ and Z ² are 6-membered rings.

Among these, as the dye (A1), from the viewpoint of ease of synthesis, salts of the dye (A1-1) to the dye (A1-4) with BF ^4- , PF _6- ^or anion (X1), respectively, are used. Preferred, salts with BF ^4- or PF ₆ ^- are particularly preferred.

Among these, as the dye (A2), from the viewpoint of ease of synthesis, salts of the dye (A2-1) to the dye (A2-6) with BF ^4- , PF _6- ^or anion (X1), respectively, are used. Preferred, salts with BF ^4- or PF ₆ ^- are particularly preferred.

As the dye (A1), for example, in the following dye (A1), R ¹⁰⁴ is -NR ¹²⁸ R ¹²⁹ , R ¹⁰¹ to R ¹⁰³ , R ¹⁰⁵ , and R ¹⁰⁷ are hydrogen atoms, ^and X- is BF ^4- . It can be synthesized as shown in the reaction pathway (F1) for obtaining the dye (f1). In the reaction pathway (F1), R ¹⁰⁶ , R ¹²⁸ , R ¹²⁹ , R ¹⁰⁸ to R ¹¹⁰ , and Z ¹ have the same meanings as in the formula (A1). In addition, Me represents a methyl group in the reaction pathway (F1). The same applies to other formulas.

The reaction pathway (F1) basically consists of the following steps 1 to 3.
<Step 1>
Compound (b1) is added to phenol (a) having an amino group substituted at R ¹²⁸ and R ¹²⁹ at the 3-position, and the mixture is heated and stirred. After completion of the reaction, the mixture is cooled to room temperature, ethyl acetate and hydrochloric acid are added, and then the mixture is extracted with hexane and ethyl acetate. After removing the solvent, the compound (c1) is isolated by column chromatography (hexane / ethyl acetate).

<Step 2>
The product (c1) obtained in step 1 is dissolved in tetrahydrofuran, methylmagnesium bromide is added dropwise, and the mixture is stirred. After completion of the reaction, the reaction solution is poured into ice water, and then an aqueous solution of tetrafluoroboric acid is added and stirred. After extraction with dichloromethane, it is dried over anhydrous magnesium sulfate to remove the solvent. The obtained solid is washed with hexane to obtain compound (d1).

<Step 3>
Aldehyde ^dianilide may have a substituent or ring Z1 in R ¹⁰⁸ to R ¹¹⁰ synthesized by a known method by dissolving the compound (d1) obtained in step 2 in pyridine. Hydrochloride (e1) is added and stirred under reflux conditions. After filtering the reaction solution, the obtained brown solid is purified by column chromatography (ethyl acetate / dichloromethane) to obtain the desired compound (f1).

Similarly, for the dye (A2), for example, in the following dye (A2), R ¹¹⁴ is −NR ¹²⁸ R ¹²⁹ , R ¹¹¹ to R ¹¹³ , R ¹¹⁵ , and R ¹¹⁷ are hydrogen atoms, and X ⁻ is. It can be synthesized as shown in the reaction pathway (F2) for obtaining the dye (f2) which is BF ^4- . In the reaction pathway (F2), R ¹¹⁶ , R ¹²⁸ , R ¹²⁹ , R ¹¹⁸ , and Z ² have the same meanings as in the formula (A2).

The reaction pathway (F2) may have the compound (b2) in place of the compound (b1) in step 1 and the substituents in R ¹⁰⁸ to R ¹¹⁰ in step 3 in the reaction pathway (F1). , Aldehyde dianilide hydrochloride (e2) which may have a substituent on R ¹¹⁸ and may have ring Z ² instead of aldehyde dianilide hydrochloride (e1) which may have ring Z ¹ . ) Is used, but the reaction is carried out in the same manner as in the reaction pathway (F1).

The dye (A) is preferably a NIR dye in which the maximum absorption wavelength λ _{max (A) DCM} is in the wavelength region of 800 to 1050 nm in the spectral transmittance measured by dissolving in dichloromethane at a wavelength of 350 to 1200 nm. Further, the dye (A) has a wavelength of 400 to 480 nm at a spectral transmittance of 350 to 1200 nm, which is measured by dissolving the dye (A) in dichloromethane so that the transmittance at the maximum absorption wavelength λ _{max (A) DCM} is 10%. The average transmittance of light in the region T _{400-480ave (A) DCM} is preferably 95% or more.

For the dye (A1), the λ _{max (A) DCM} can be approximately 900 to 1050 nm depending on the type of substituent. Further, for the dye (A1), T _{400-480ave (A) DCM} can be approximately 95% or more. The dye (A1) is a dye having excellent absorption characteristics in a long wavelength region among NIR dyes. Among conventional NIR dyes in which the maximum absorption wavelength in dichloromethane is in the same long wavelength range as the dye (A1), there is no known dye having an average transmittance of light in the wavelength region of 400 to 480 nm as high as that of the dye (A1). ..

For the dye (A2), the λ _{max (A) DCM} can be approximately 800 to 850 nm depending on the type of substituent. Further, for the dye (A2), T _{400-480ave (A) DCM} can be approximately 95% or more. The dye (A2) is a NIR dye capable of achieving both absorbability in λ _{max (A) DCM} and light transmission in the wavelength region of 400 to 480 nm at a very high level.

The absorption layer may contain one type of dye (A) alone, or may contain two or more types in combination. The absorption layer is typically configured in which the dye (A) is uniformly dissolved or dispersed in the transparent resin.

The dye (A) preferably has a maximum mass absorption coefficient of 1500 / (cm · mass%) or more in light having a wavelength of 350 to 1200 nm when it is contained in the transparent resin contained together with the absorption layer. In the following description, the "transparent resin" means a transparent resin contained in the absorption layer together with the dye (A).

The maximum mass absorption coefficient of the dye (A1) when contained in the transparent resin is more preferably 1800 / (cm · mass%) or more. The maximum mass absorption coefficient of the dye (A2) when contained in the transparent resin is more preferably 2000 / (cm · mass%) or more.

In the dye (A), the maximum absorption wavelength λ _{max (A) TR} obtained from the spectral transmittance curve having a wavelength of 350 to 1200 nm measured by containing it in the transparent resin is usually the maximum absorption wavelength λ _max (A) in dichloromethane. _{) Within ± 10 nm of DCM} . The dye (A) has a transmittance of 400 to 480 nm in a spectral transmittance curve having a wavelength of 350 to 1200 nm, which is measured by containing the dye (A) in a transparent resin so that the transmittance at the maximum absorption wavelength λ _{max (A) TR} is 10%. The average transmittance T _{400-480ave (A) TR} of light in the wavelength region is preferably 82% or more.

As for the dye (A1), T _{400-480ave (A) TR} is more preferably 83.5% or more. As for the dye (A2), T _{400-480ave (A) TR} is more preferably 87% or more.

The absorption layer may contain other NIR dyes in addition to the dye (A) as long as the effects of the present invention are not impaired. Further, the absorption layer may contain a dye other than the NIR dye, particularly a UV dye, as long as the effect of the present invention is not impaired.

As the other NIR dye, a dye (D) having a maximum absorption wavelength λ _{max (D) DCM} at 600 to 750 nm in a spectral transmittance of a wavelength of 350 to 1200 nm measured by a solution dissolved in dichloromethane is preferable.

Further, the dye (D) has a spectral transmittance at a wavelength of 400 to 1100 nm, which is measured in solution when dissolved in dichloromethane so that the light transmittance at the maximum absorption wavelength λ _{max (D) DCM} is 10%. The average transmittance T _{550-650ave (D) DCM} in the wavelength region of light of 550 to 650 nm is preferably 90% or more.

Further, in the light absorption spectrum of the dye (D), it is preferable that the absorption peak having the absorption peak in the λ _{max (D) DCM} has a steep slope on the visible light side. Further, it is preferable that the absorption peak having the absorption apex in the λ _{max (D) DCM} has a gentle slope on the long wavelength side.

[Dye (D)]
As the dye (D), λ _{max (D) DCM} is in the above range, and preferably T _{550-650ave (D) DCM} further satisfies the above requirements, cyanine dye, phthalocyanine dye, naphthalocyanine dye, dithiol metal complex dye. , At least one pigment selected from the group consisting of diimonium pigments, polymethine pigments, phthalide pigments, naphthoquinone pigments, anthraquinone pigments, indophenol pigments, and squarylium pigments.

Among these, a squarylium dye is particularly preferred, wherein the λ _{max (D) DCM} is in the above range, and more preferably the _{T550-650ave (D) DCM} meets the above requirements. The dye (D) made of a squarylium dye absorbs less visible light in the above absorption spectrum, and the absorption peak having an absorption peak at λ _{max (D) DCM} has a steep slope on the visible light side and is stable in storage. Highly stable against sex and light.

The dye (D), which is a squarylium dye, is preferably a compound represented by any of the formulas (I) to (III) in which λ _{max-DCM (A)} is in the wavelength region of 600 to 750 nm. The mass extinction coefficient of the dye (D) in the transparent resin shows the maximum value in light having a wavelength of 600 to 750 nm, and the maximum mass extinction coefficient is preferably 1000 / (cm · mass%) or more, 1500 / (cm · ·. Mass%) or more is more preferable.

However, the symbols in the formula (I) are as follows.
R ²⁴ and R ²⁶ are independently hydrogen atom, halogen atom, hydroxyl group, alkyl group or alkoxy group having 1 to 6 carbon atoms, acyloxy group having 1 to 10 carbon atoms, -NR ²⁷ R ²⁸ (R ²⁷ and R 27 and). Each of R ²⁸ has a hydrogen atom and an alkyl group having 1 to 20 carbon atoms, and -C (= O) -R ²⁹ (R ²⁹ has a hydrogen atom and a substituent having 1 to 20 carbon atoms. Alaryl groups having 7 to 18 carbon atoms, which may have an alkyl group of up to 20 or an aryl group having 6 to 11 carbon atoms, or an oxygen atom between carbon atoms),-. NHR ³⁰ or -SO ₂ -R ³⁰ (R ³⁰ may each have one or more hydrogen atoms substituted with halogen atoms, hydroxyl groups, carboxy groups, sulfo groups, or cyano groups, between carbon atoms. A hydrocarbon group having 1 to 25 carbon atoms which may contain an unsaturated bond, an oxygen atom, and a saturated or unsaturated ring structure)) or a group represented by the following formula (S) (R ⁴¹ , R ⁴² ). Independently indicate a hydrogen atom, a halogen atom, or an alkyl group or an alkoxy group having 1 to 10 carbon atoms. K is 2 or 3).

R ²¹ and R ²² , R ²² and R ²⁵ , and R ²¹ and R ²³ are linked to each other to form a heterocycle A, a heterocycle B, and a heterocycle C having 5 or 6 members, respectively, together with a nitrogen atom. May be good.
When the heterocyclic ring A is formed, R ²¹ and R ²² have a divalent group −Q— to which the hydrogen atom is bonded, such as an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms. An alkylene group or an alkyleneoxy group which may be substituted with an acyloxy group having 1 to 10 carbon atoms which may have a substituent is shown.

R ²² and R ²⁵ when the heterocycle B is formed, and R ²¹ and R ²³ when the heterocycle C is formed are divalent groups to which they are bonded-X1 ^- Y1 ^- and-, respectively. As X ² -Y ^2- (the side that binds to nitrogen is X ¹ and X ² ), X ¹ and X ² are the groups represented by the following formulas (1x) or (2x), respectively, and Y ¹ and Y ² are the groups, respectively. It is a group represented by any of the following formulas (1y) to (5y). When X ¹ and X ² are groups represented by the following formulas (2x), Y ¹ and Y ² may be single bonds, respectively, and in that case, oxygen atoms may be provided between carbon atoms. ..

In the formula (1x), the four Zs are independently hydrogen atoms, hydroxyl groups, alkyl or alkoxy groups having 1 to 6 carbon atoms, or -NR ³⁸ R ³⁹ (R ³⁸ and R ³⁹ are independent, respectively. Indicates a hydrogen atom or an alkyl group having 1 to 20 carbon atoms). R ³¹ to R ³⁶ are independent hydrogen atoms, alkyl groups having 1 to 6 carbon atoms or aryl groups having 6 to 10 carbon atoms, and R ³⁷ is an alkyl group having 1 to 6 carbon atoms or 6 to 10 carbon atoms. Indicates an aryl group.

R ²⁷ , R ²⁸ , R ²⁹ , R ³¹ to R ³⁷ , R ²¹ to R ²³ when no heterocycle is formed, and R ²⁵ are 5-membered rings coupled to any other of these. Alternatively, a 6-membered ring may be formed. R ³¹ and R ³⁶ and R ³¹ and R ³⁷ may be directly coupled.
When the heterocycle is not formed, R ²¹ and R ²² each independently have a hydrogen atom, an alkyl group or an allyl group having 1 to 6 carbon atoms which may have a substituent, or a substituent. An aryl group or an alaryl group having 6 to 11 carbon atoms which may be possessed is shown. When the heterocycle is not formed, R ²³ and R ²⁵ independently represent a hydrogen atom, a halogen atom, or an alkyl group or an alkoxy group having 1 to 6 carbon atoms.

However, the symbols in equation (II) are as follows.
Ring Z is a 5-membered or 6-membered ring that independently has 0 to 3 heteroatoms in the ring and may be substituted.
The carbon atoms or heteroatoms constituting ^R1 and ^R2 , ^R2 and R3 ^, and ^R1 and ring Z are linked to each other to form a hetero ring A1, a hetero ring B1 and a hetero ring C1 together with a nitrogen atom, respectively. If they do not form a heteroatom, ^R1 and ^R2 are independently unsaturated bonds, heteroatoms, saturated or unsaturated between hydrogen atoms, halogen atoms, or carbon atoms. Representing a hydrocarbon group which may contain a ring structure and may have a substituent, R ³ and R ⁴ may independently contain a heteroatom between a hydrogen atom, a halogen atom, or a carbon atom. Indicates an alkyl group or an alkoxy group.

However, the symbols in equation (III) are as follows.
R ⁵¹ represents an alkyl group having 1 to 3 carbon atoms, which may independently have a halogen atom or a substituent.
R ⁵² to R ⁵⁸ indicate an alkyl group having 1 to 10 carbon atoms which may independently have a hydrogen atom, a halogen atom, or a substituent.
R ⁵² and R ⁵³ may be connected to each other to form a saturated or unsaturated hydrocarbon ring B2 having 5 to 15 carbon atoms, and the hydrogen atom of the hydrocarbon ring B2 may be an alkyl having 1 to 10 carbon atoms. It may be substituted with a group,
R ⁵⁴ and R ⁵⁵ may be linked to each other to form a benzene ring A2, and the hydrogen atom of the benzene ring A2 may be substituted with an alkyl group having 1 to 10 carbon atoms.

Examples of the compound (I) include compounds represented by any of the formulas (I-1) to (I-4).

However, the symbols in the formulas (I-1) to (I-4) are the same as the respective provisions of the same symbols in the formula (I), and the preferred embodiments are also the same.

Among the compounds (I-1) to (I-4), the dye (D) is preferably the compounds (I-1) to (I-3) from the viewpoint of increasing the visible light transmittance of the absorption layer. Compound (I-1) is particularly preferred.

In compound (I-1), X ¹ is preferably a group (2x), and Y ¹ is preferably a single bond or a group (1y). In this case, as R ³¹ to R ³⁶ , a hydrogen atom or an alkyl group having 1 to 3 carbon atoms is preferable, and a hydrogen atom or a methyl group is more preferable. Specific examples of −Y ¹ − X ¹ − include divalent organic groups represented by the formulas (11-1) to (12-3).

-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 ) (nC ₃ H ₇ )-... (11-4)
-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)

Further, in compound (I-1), R ²¹ independently contains the formula (4) from the viewpoint of solubility, heat resistance, and steepness of change in the spectral transmittance near the boundary between the visible region and the near infrared region. The group represented by -1) or (4-2) is more preferable.

In formulas (4-1) and (4-2), R ⁷¹ to R ⁷⁵ independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms.

In compound (I-1), R ²⁴ is preferably -NR ²⁷ R ²⁸ . As the -NR ²⁷ R ²⁸ , -NH-C (= O) -R ²⁹ is preferable from the viewpoint of solubility in a host solvent or a transparent resin. In compound (I-1), the compound in which R ²⁴ is -NH-C (= O) -R ²⁹ is represented by the formula (I-11).

In the compound (I-11), R ²³ and R ²⁶ are independently preferable to be a hydrogen atom, a halogen atom, or an alkyl group or an alkoxy group having 1 to 6 carbon atoms, and a hydrogen atom is more preferable.

In the compound (I-11), as R ²⁹ , an alkyl group having 1 to 20 carbon atoms which may have a substituent, an aryl group having 6 to 10 carbon atoms which may have a substituent, or an aryl group having 6 to 10 carbon atoms may be used. Alaryl groups having 7 to 18 carbon atoms, which may have a substituent and may have an oxygen atom between carbon atoms, are preferable. The substituents include a halogen atom such as a fluorine atom, a hydroxyl group, a carboxy group, a sulfo group, a cyano group, an alkyl group having 1 to 6 carbon atoms, a fluoroalkyl group having 1 to 6 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms. , Acyloxy groups having 1 to 6 carbon atoms and the like.

As R ²⁹ , a linear, branched, cyclic alkyl group having 1 to 17 carbon atoms, a fluoroalkyl group having 1 to 6 carbon atoms and / or a cyclic alkyl group having 1 to 6 carbon atoms which may be substituted with a fluorine atom may be used. A phenyl group that may be substituted with an alkoxy group, and an alkyl that may have an oxygen atom between carbon atoms and may be substituted with a fluorine atom having 7 to 18 carbon atoms and having 1 to 6 carbon atoms at the terminal. A group selected from an alaryl group having a phenyl group which may be substituted with a group and / or an alkoxy group having 1 to 6 carbon atoms is preferable.

As R ²⁹ , one or more hydrogen atoms may be independently substituted with a halogen atom, a hydroxyl group, a carboxy group, a sulfo group, or a cyano group, and unsaturated bonds, oxygen atoms, saturation or A group which is a hydrocarbon group having 5 to 25 carbon atoms and having at least one branch, which may contain an unsaturated ring structure, can also be preferably used. Examples of such R ²⁹ include groups represented by the following formulas (1a), (1b), (2a) to (2e), and (3a) to (3e).

More specifically, the compound (I-11) includes the compounds shown in Table 3 below. In Table 3, the group (11-1) is referred to as (11-1). The same applies to other groups. The display of the basis is the same in the other tables below. In addition, the compounds shown in Table 3 have the same meaning of each symbol on the left and right sides of the squarylium skeleton. The same applies to the squarylium dyes shown in the other tables below.

In compound (I-1), R ²⁴ is preferably -NH-SO ₂ -R ³⁰ from the viewpoint of increasing the transmittance of visible light, particularly the transmittance of light having a wavelength of 430 to 550 nm. In compound (I-1), the compound in which R ²⁴ is -NH-SO ₂ -R ³⁰ is represented by the formula (I-12).

In the compound (I-12), R ²³ and R ²⁶ are independently preferable to be a hydrogen atom, a halogen atom, or an alkyl group or an alkoxy group having 1 to 6 carbon atoms, and a hydrogen atom is more preferable.

In compound (I-12), R ³⁰ has an alkyl group or an alkoxy group having 1 to 12 carbon atoms which may have a branch independently from the viewpoint of light resistance, or a carbon number having an unsaturated ring structure. 6 to 16 hydrocarbon groups are preferred. Examples of the unsaturated ring structure include benzene, toluene, xylene, furan, and benzofuran. R ³⁰ is more preferably an alkyl group or an alkoxy group having 1 to 12 carbon atoms which may independently have a branch. In each group showing R ³⁰ , a part or all of a hydrogen atom may be substituted with a halogen atom, particularly a fluorine atom. When this filter includes a transparent substrate, the hydrogen atom is replaced with a fluorine atom so that the adhesion between the absorption layer containing the dye (I-12) and the transparent substrate does not deteriorate.

Specific examples of the R ³⁰ having an unsaturated ring structure include groups represented by the following formulas (P1) to (P8).

More specifically, the compound (I-12) includes the compounds shown in Table 4 below.

Examples of the compound (II) include compounds represented by any of the formulas (II-1) to (II-3).

However, in the formulas (II-1) and (II-2), R ¹ and R ² may independently have a hydrogen atom, a halogen atom, or a substituent, respectively, and are alkyl having 1 to 15 carbon atoms. The groups are shown, and R ³ to R ⁶ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms which may have a substituent.

However, in the formula (II-3), R ¹ , R ⁴ , and R ⁹ to R ¹² are alkyl having 1 to 15 carbon atoms which may independently have a hydrogen atom, a halogen atom, or a substituent. Representing a group, R ⁷ and R ⁸ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms which may have a substituent.

R ¹ and R ² in compound (II-1) and compound (II-2) independently have an alkyl group having 1 to 15 carbon atoms from the viewpoint of solubility in a transparent resin, visible light transmission, and the like. Preferably, an alkyl group having 7 to 15 carbon atoms is more preferable, an alkyl group having at least one of R ¹ and R ² having a branched chain having 7 to 15 carbon atoms is more preferable, and both R ¹ and R ² have carbon atoms. Alkyl groups having 8 to 15 branched chains are particularly preferred.

R ³ is preferably an alkyl group having a hydrogen atom, a halogen atom, or 1 to 3 carbon atoms, and a hydrogen atom, a halogen atom, or a methyl group, independently from the viewpoint of solubility in a transparent resin, visible light transmission, and the like. More preferred. ^R4 is preferably a hydrogen atom or a halogen atom, and particularly preferably a hydrogen atom, from the viewpoint of steepness of change near the boundary between the visible region and the near infrared region. R5 in compound (II-1) and R6 in compound (II- ² ) are preferably alkyl groups having 1 to ⁵ carbon atoms which may be independently substituted with a hydrogen atom, a halogen atom or a halogen atom. , Hydrogen atom, halogen atom, methyl group are more preferable.

Specific examples of the compound (II-1) and the compound (II-2) include the compounds shown in Tables 5 and 6 below, respectively. In Tables 5 and 6, -C ₈ H ₁₇ , -C ₄ H ₉ , and -C ₆ H ₁₃ represent linear octyl groups, butyl groups, and hexyl groups, respectively.

R ¹ in compound (II-3) is preferably an alkyl group having 1 to 15 carbon atoms, and an alkyl group having 1 to 10 carbon atoms, independently from the viewpoint of solubility in a transparent resin, visible light transmission, and the like. Is more preferable, and an ethyl group and an isopropyl group are particularly preferable.

From the viewpoint of visible light transmission and ease of synthesis, ^R4 is preferably a hydrogen atom or a halogen atom, and particularly preferably a hydrogen atom. R ⁷ and R ⁸ are preferably an alkyl group having 1 to 5 carbon atoms which may be independently substituted with a hydrogen atom, a halogen atom or a halogen atom, and more preferably a hydrogen atom, a halogen atom or a methyl group.

R ⁹ to R ¹² are preferably alkyl groups having 1 to 5 carbon atoms which may be independently substituted with a hydrogen atom, a halogen atom or a halogen atom. Examples of -CR ⁹ R ¹⁰ -CR ¹¹ R ^12- include the above groups (11-1) to (11-3) or divalent organic groups represented by the following formula (11-5).
-C (CH ₃ ) (CH ₂ -CH (CH ₃ ) ₂ ) -CH (CH ₃ ) -... (11-5)

More specifically, the compound (II-3) includes the compounds shown in Table 7 below.

Examples of the compound (III) include compounds represented by either the formula (III-1) or the formula (III-2).

However, in (III-1) and (III-2), R ⁵² to R ⁶² each independently have a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms which may have a substituent. show.

In compound (III-1) and compound (III-2), R ⁵² and R ⁵³ independently have an alkyl group having 1 to 6 carbon atoms which may be substituted with a hydrogen atom, a halogen atom or a halogen atom. Preferably, a hydrogen atom, a halogen atom and a methyl group are more preferable. R ⁵⁸ is preferably an alkyl group having 1 to 6 carbon atoms which may be substituted with a hydrogen atom, a halogen atom or a halogen atom, and more preferably an alkyl group having 1 to 3 carbon atoms from the viewpoint of easiness of synthesis. R ⁵⁶ , R ⁵⁷ , and R ⁵⁹ to R ⁶² are preferably alkyl groups having 1 to 6 carbon atoms, which may independently have hydrogen atoms, halogen atoms, or substituents, respectively, from the viewpoint of ease of synthesis. Hydrogen atoms are more preferred. Specific examples of the compound (III-1) and the compound (III-2) include the compounds shown in Tables 8 and 9 below, respectively.

The dye (D) may be composed of one kind of compound or two or more kinds of compounds. When composed of two or more kinds of compounds, each compound does not necessarily have the property of the dye (D), and may have the property of the dye (D) as a mixture.

The compounds (I) to (III) can be synthesized by known methods. For compound (I), compound (I-11) can be synthesized, for example, by the method described in US Pat. No. 5,543,086. Compound (I-12) can be synthesized, for example, by the methods described in US Patent Application Publication No. 2014/0061505 and International Publication No. 2014/088063. Compound (II) can be synthesized by the method described in International Publication No. 2017/135359.

The composition of the dye (D) can be appropriately selected according to the design of the present filter. The dye (D) may be, for example, a mixture of the dye (D1) and the dye (D2) having the following characteristics, and may consist only of the dye (D1).

(A-1) The dye (D1) is one or more selected from the compounds (I) to (III) and has a maximum absorption at a spectral transmission rate of 400 to 1100 nm measured by containing it in a transparent resin. The wavelength λ _{max (D1) TR} is in the wavelength region of 680 to 730 nm, and the wavelength is shorter than the maximum absorption wavelength λ _{max (D1) TR} when the transmission rate of the maximum absorption wavelength λ _max (D1) TR is adjusted to 10%. The difference between the wavelength at which the light transmission rate on the side is 80% (hereinafter referred to as “λ _{SH80 (D1)} ”) and the maximum absorption wavelength λ _{max (D1) TR} is 100 nm or less.

(A-2) The dye (D2) is one or more selected from the compounds (I) to (III) and has a maximum absorption at a spectral transmittance of a wavelength of 400 to 1100 nm measured by being contained in a transparent resin. The wavelength λ _{max (D2) TR} is in the wavelength region of 720 to 770 nm.

(A-3) The value obtained by subtracting the maximum absorption wavelength λ _{max (D1) TR from the maximum absorption wavelength λ max (D2) TR} is 30 nm or more and 85 nm or less.

Examples of the dye (D1) include compound (I), compound (II-1), and compound (II-2) among compounds (I) to (III), and compound (I-11-7) and compound. (I-12-15), compound (I-12-23), compound (I-12-24), compound (II-1-7) and the like are preferable. Examples of the dye (D2) include compound (II-3), compound (III-1), and compound (III-2) among compounds (I) to (III).

The dye (D) is preferably a compound whose absorption layer obtained when used together with the dye (A) satisfies the requirements of (ii-1) to (ii-3) described later.

Specific examples of the UV dye include oxazole-based, merocyanine-based, cyanine-based, naphthalimide-based, oxadiazole-based, oxazine-based, oxazolidine-based, naphthalic acid-based, styryl-based, anthracene-based, cyclic carbonyl-based, and triazole-based. Pigments can be mentioned. Of these, oxazole-based and merocyanine-based dyes are preferable. In addition, one type of UV dye may be used alone for the absorption layer, or two or more types may be used in combination.

The type of the transparent resin is not particularly limited as long as it is a resin that transmits light having a wavelength of 400 to 900 nm. Since the transparent resin has such properties, the dye (A) and the dye (D) can be evaluated as described above without considering the absorption of the transparent resin.

As transparent resins, polyester resin, acrylic resin, epoxy resin, en-thiol resin, polycarbonate resin, polyether resin, polyarylate resin, polysulfone resin, polyether sulfone resin, polyparaphenylene resin, polyarylene ether phosphine oxide resin , Polyamitone resin, polyimide resin, polyamideimide resin, polyolefin resin, cyclic olefin resin, polyurethane resin, acrylicimide resin, polystyrene resin and the like. One of these resins may be used alone, or two or more of these resins may be mixed and used.

The transparent resin has a high glass transition point (Tg) from the viewpoint of transparency, solubility of the dye (A) and further the dye (D), and heat resistance, for example, a resin having a Tg of 140 ° C. or higher. Is preferable. Specifically, one or more selected from polyester resin, polycarbonate resin, polyether sulfone resin, polyarylate resin, polyimide resin, acrylicimide resin and epoxy resin is preferable, and polyester resin, polycarbonate resin, polyimide resin and acrylicimide are preferable. One or more selected from the resins are more preferable.

The absorption layer further comprises an adhesion imparting agent, a color tone correcting dye, a leveling agent, an antistatic agent, a heat stabilizer, a light stabilizer, an antioxidant, a dispersant, and a flame retardant, as long as the effects of the present invention are not impaired. It may have an arbitrary component such as a lubricant and a plasticizer.

The content of the dye (A) in the absorption layer can be appropriately selected according to the design of the present filter. The content of the dye (A) in the absorption layer is preferably 0.01 to 20 parts by mass with respect to 100 parts by mass of the transparent resin from the viewpoint of shielding near infrared light while ensuring the transmittance of visible light. From the viewpoint of solubility, 0.03 to 10 parts by mass is more preferable.

When the absorption layer contains the dye (A) and the dye (D), the content thereof is appropriately selected according to the design of the present filter. The content of the dye (A) in the absorption layer is the same as above, and the content of the dye (D) is a transparent resin from the viewpoint of being able to exhibit the characteristics of the dye (D) while ensuring the transmittance of visible light. 0.01 to 20 parts by mass is preferable, and 0.03 to 15 parts by mass is more preferable with respect to 100 parts by mass. Further, the total content of the dye (A) and the dye (D) is preferably 0.03 to 20 parts by mass, more preferably 0.03 to 15 parts by mass with respect to 100 parts by mass of the transparent resin.

In this filter, the thickness of the absorption layer is preferably 0.1 to 100 μm. When the absorption layer is composed of a plurality of layers, the total thickness of each layer is preferably 0.1 to 100 μm. If the thickness is less than 0.1 μm, the desired optical characteristics may not be sufficiently exhibited, and if the thickness is more than 100 μm, the flatness of the layer may be lowered and the absorption rate may vary in the plane. The thickness of the absorption layer is more preferably 0.3 to 50 μm. Further, when a reflective layer or another functional layer such as an antireflection layer is provided, cracking or the like may occur if the absorbing layer is too thick depending on the material thereof. Therefore, the thickness of the absorption layer is more preferably 0.3 to 10 μm.

In the absorption layer, for example, the dye (A), preferably the dye (A) and the dye (D), the raw material component of the transparent resin or the transparent resin, and each component to be blended as necessary are dissolved in a solvent. Alternatively, it can be dispersed to prepare a coating liquid, which can be applied to a substrate, dried, and further cured if necessary to form the coating liquid. The base material may be a transparent substrate included in the present filter, or may be a peelable base material used only when forming an absorption layer. The solvent may be a dispersion medium that can be stably dispersed or a solvent that can be dissolved.

Further, the coating liquid may contain a surfactant for improving voids due to minute bubbles, dents due to adhesion of foreign substances, repellency in the drying step, and the like. Further, for the coating of the coating liquid, for example, a dip coating method, a cast coating method, a spin coating method or the like can be used. An absorbent layer is formed by applying the above coating liquid on a substrate and then drying it. When the coating liquid contains a raw material component of a transparent resin, further curing treatment such as heat curing and photocuring is performed.

Further, the absorption 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, if the filter includes a transparent substrate, this film may be attached onto the transparent substrate.

The absorption layer may have one layer or two or more layers in the present filter. When having two or more layers, each layer may have the same configuration or may be different. Taking the case where the absorption layer contains a dye (A), a dye (D) and a UV dye as an example, one layer is a near-infrared absorption layer containing the dye (A) and the dye (D) and a transparent resin. The other layer may be a near-ultraviolet absorption layer containing a UV dye and a transparent resin. As another example, one layer is a first near-infrared absorption layer containing a dye (D) and a transparent resin, and the other layer is a second near-infrared layer containing a dye (A), a UV dye and a transparent resin. It may be an infrared absorption layer. Further, the absorption layer itself may function as a substrate (resin substrate).

(Transparent board)
When a transparent substrate is used for this filter, the transparent substrate is not particularly limited as long as it transmits visible light of about 400 to 700 nm, and may be a material that absorbs near-infrared light or near-ultraviolet light. Examples thereof include inorganic materials such as glass and crystals, and organic materials such as transparent resins.

Glasses that can be used for transparent substrates include absorbent glass (near-infrared absorbing glass) containing copper ions in fluoride-based glass, phosphate-based glass, etc., soda lime glass, borosilicate glass, non-alkali glass, and quartz. Examples include glass. The "phosphate-based glass" also includes silicate glass in which a part of the skeleton of the glass is composed of SiO ₂ .

As for glass, alkali metal ions (for example, Li ion and Na ion) having a small ion radius existing on the main surface of the glass plate are converted into alkali ions having a larger ion radius (for example) by ion exchange at a temperature below the glass transition point. , It is Na ion or K ion for Li ion, and K ion for Na ion.) You may use the chemically strengthened glass obtained by exchanging with the ion.

Examples of the transparent resin material that can be used as a transparent substrate include polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyolefin resins such as polyethylene, polypropylene and ethylene vinyl acetate copolymers, and acrylic resins such as norbornene resin, polyacrylate and polymethylmethacrylate. , Urethane resin, vinyl chloride resin, fluororesin, polycarbonate resin, polyvinyl butyral resin, polyvinyl alcohol resin, polyimide resin and the like.

Examples of the crystal material that can be used for the transparent substrate include birefringent crystals such as quartz, lithium niobate, and sapphire. The optical characteristics of the transparent substrate may have the above-mentioned optical characteristics as an optical filter obtained by laminating the absorption layer, the reflection layer, or the like. Sapphire is preferable as the crystal material.

The transparent substrate is preferably an inorganic material, and particularly preferably glass or sapphire, from the viewpoint of shape stability related to long-term reliability such as optical properties as an optical filter and mechanical properties, and handleability during filter manufacturing.

The shape of the transparent substrate is not particularly limited, and may be block-shaped, plate-shaped, or film-shaped, and the thickness thereof is preferably, for example, 0.03 to 5 mm, and from the viewpoint of thinning, 0.03 to 0.5 mm. Is more preferable. From the viewpoint of processability, a transparent substrate made of glass and having a plate thickness of 0.05 to 0.5 mm is preferable.

(Reflective layer)
The reflective layer is made of a dielectric multilayer film and has a function of shielding light in a specific wavelength range. Examples of the reflective layer include those having wavelength selectivity that transmits visible light and mainly reflects light having a wavelength other than the light-shielding region of the absorption layer. The reflective layer preferably has a reflective region that reflects near-infrared light. In this case, the reflection region of the reflection layer may include a light-shielding region in the near-infrared region of the absorption layer. The reflective layer is not limited to the above characteristics, and may be appropriately designed to have specifications that further shield light in a predetermined wavelength range, for example, the near-ultraviolet region.

When the absorption layer contains the dye (D) in addition to the dye (A) and the reflection layer has a reflection region for reflecting near-infrared light, it is preferable that the absorption layer and the reflection layer have the following relationship.

The absorption layer has a wavelength λ _AB-SHT20 on the short wavelength side of the wavelength showing a transmittance of 20% in an absorption region having an incident angle of 0 degrees in a wavelength region of 630 to 690 nm, and the reflecting layer is a reflection having an incident angle of 0 degrees. It is preferable that the wavelength λ _RE-SHT 20 on the short wavelength side showing a transmittance of 20% in the region satisfies the following relationship.
λ _AB-SHT20 + 30nm ≤ λ _RE-SHT20 ≤ λ _AB-SHT20 + 70nm

The reflective layer preferably has an average transmittance of 10% or less in light in the wavelength region from λ RE _-SHT20 to λ _RE-SHT20 + 300 nm.

The reflective layer is composed of a dielectric multilayer film in which 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 the material of the high refractive index film include Ta ₂ O ₅ , TIO ₂ , and Nb ₂ O ₅ . Of these, TiO ₂ is preferable from the viewpoints of film formation property, reproducibility in refractive index and the like, stability and the like.

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 the material of the low refractive index film include SiO ₂ , SiO _x N _y and the like. SiO ₂ is preferable from the viewpoint of reproducibility, stability, economy and the like in terms of film forming property.

Further, it is preferable that the transmittance of the reflective layer changes sharply in the boundary wavelength region between the transmissive region and the light-shielding region. For this purpose, the total number of laminated dielectric multilayer films constituting the reflective layer is preferably 15 or more, more preferably 25 or more, and even more preferably 30 or more. However, when the total number of layers increases, warpage or the like occurs or the film thickness increases. Therefore, the total number of layers is preferably 100 layers or less, more preferably 75 layers or less, and even more preferably 60 layers or less. The film thickness of the dielectric multilayer film is preferably 2 to 10 μm.

When the total number of laminated dielectric layers and the film thickness are within the above ranges, the reflective layer can satisfy the requirements for miniaturization, and can reduce the dependence on the incident angle while maintaining high productivity. Further, for forming the dielectric multilayer film, for example, a vacuum film forming process such as a CVD method, a sputtering method or a vacuum vapor deposition method, a wet film forming process such as a spray method or a dip method can be used.

As the reflective layer, one layer (a group of dielectric multilayer films) may give a predetermined optical characteristic, or two layers may give a predetermined optical characteristic. When having two or more layers, each reflective layer may have the same configuration or a different configuration. When having two or more reflective layers, it is usually composed of a plurality of reflective layers having different reflection bands.

As an example, when two reflective layers are provided, one is a near-infrared reflective layer that shields light in a short wavelength band in the near-infrared region, and the other is a long-wavelength band and a near-ultraviolet region in the near-infrared region. It may be a near-infrared / near-ultraviolet reflective layer that shields light in both regions. Further, for example, when the present filter has a transparent substrate and two or more reflective layers are provided, all of them may be provided on one main surface of the transparent substrate, and each reflective layer may be provided on the transparent substrate. It may be sandwiched and provided on both main surfaces.

(Anti-reflective layer)
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. Of these, a dielectric multilayer film is preferable from the viewpoint of optical efficiency and productivity. The antireflection layer is obtained by alternately laminating dielectric films like the reflection layer.

As other components, the filter may include, for example, a component (layer) that provides absorption by inorganic fine particles or the like that controls the transmission and absorption of light in a specific wavelength range. Specific examples of the inorganic fine particles include ITO (Indium Tin Oxides), ATO (Antimony-doped Tin Oxides), cesium tungstate, lanthanum borate and the like. The ITO fine particles and the cesium tungstate fine particles have high visible light transmittance and have light absorption over a wide range in the infrared wavelength region exceeding 1200 nm, and thus can be used when such infrared light shielding properties are required. ..

In this filter, since the absorption layer contains the dye (A), the wavelength range corresponding to the absorption type glass, particularly, in terms of the shielding property of near-infrared light, while maintaining good transmission of visible light. Can achieve a high level of shielding of near-infrared light in the wavelength range of 800 to 1050 nm. Furthermore, it has excellent light resistance. When the absorption layer contains the dye (D) in addition to the dye (A), it is possible to shield the near-infrared light near the boundary with the visible light in addition to the above wavelength range.

In addition, when the filter has a reflective layer, the filter can suppress the incident angle dependence of the reflective layer with respect to the light incident at a high angle by the reflective layer, particularly light leakage in the wavelength range of 800 to 1050 nm at a high incident angle. Can be reduced.

When this filter has an absorbent layer and a reflective layer containing the dye (A) and the dye (D), it is preferable to satisfy the following optical characteristics (i-1) to (i-6).
(I-1) The average transmittance in the wavelength region of 435 to 480 nm at an incident angle of 0 degrees is 75% or more.
(I-2) The average transmittance in the wavelength region of 703 to 739 nm at an incident angle of 0 degrees is 3% or less.
(I-3) The average transmittance in the wavelength region of 703 to 739 nm at an incident angle of 30 degrees is 3% or less.
(I-4) The absolute value of the value obtained by subtracting the average transmittance of 703 to 739 nm at an incident angle of 30 degrees from the average transmittance of 703 to 739 nm at an incident angle of 0 degrees is 3% or less.
(I-5) The transmittance at 846 nm at an incident angle of 0 degrees is 3% or less.
(I-6) The transmittance at 846 nm at an incident angle of 50 degrees is 3% or less.

This filter can provide an image pickup device having excellent color reproducibility when used in an image pickup device such as a digital still camera, for example. An image pickup device using this filter includes a solid-state image pickup element, an image pickup lens, and this filter. This filter can be used, for example, by being arranged between an image pickup lens and a solid-state image pickup element, or by being directly attached to a solid-state image pickup element, an image pickup lens, or the like of an image pickup device via an adhesive layer.

Examples of the present invention will be described below. First, examples and characteristics of the dye (A) and the dye (D) used for the absorption layer of the examples and other dyes for comparison will be described. Next, an example of the optical filter will be described.

<Dye synthesis / preparation>
As the dye (A) used in the examples, the dye ( A2-2B), (A2-2X1), (A2-3B), (A2-4B), (A2-5B), (A2-5B), which is the dye (A2). A2-6B), dye (A1) dye (A1-1B), (A1-2B) , and dye (A2) dye (A2-1B), (A2) as the dye (A) used in the comparative example. The dye (I-12-24) was synthesized by a conventional method using -1X1) as the dye (D) by the following method. In the formula, "Et" indicates an ethyl group and "tBu" indicates a tertiary butyl group. "N (SO ₂ CF ₃ ⁾ _2- " is an anion represented by the formula (X1).

Further, as the dye used in the comparative example, the cyanine dye (Acf1) represented by the following formula (Acf1) was synthesized by a conventional method. Further, as commercially available dyes, the cyanine dye S0734 (trade name manufactured by Few Chemicals) represented by the following formula (Acf2) and the diimonium dye Dim01 represented by the following formula (Acf4) (Japanese Patent Laid-Open No. 2014-25016). (Synthesized by the method described), and four types of phthalocyanine dyes, FDN-002, FDN-003, FDN-015, and FDN-021 (all of which are trade names manufactured by Yamada Chemical Co., Ltd.) were prepared.

An ultraviolet-visible spectrophotometer (U-4100, manufactured by Hitachi High-Technologies Corporation) was used to evaluate the optical characteristics of these dyes, and the same applies to the evaluation of the following optical characteristics (spectral transmittance). U-4100 was used.

(1) Synthesis of dye (A2-1B) A dye (A2-1B) was synthesized according to the reaction pathway shown below.

<Step 1>
Add N, N-diethyl-3-aminophenol (5 g, 30.3 mmol) and methyl 4,4-dimethyl-3-oxovalerate (6.1 g, 60.6 mmol) to a 200 ml eggplant flask to create a nitrogen atmosphere. After heating and stirring at 180 ° C. for 35 hours, methyl 4,4-dimethyl-3-oxovalerate (6.1 g, 60.6 mmol) was added again and the mixture was heated and stirred for 15 hours. After cooling to room temperature and adding ethyl acetate and 0.5 M hydrochloric acid, the mixture was extracted with hexane and ethyl acetate. After removing the solvent, a brown oily substance (4.6 g, 21.2 mmol, 70% yield) was isolated by column chromatography (hexane / ethyl acetate).

<Step 2>
The brown oily substance (4 g, 18.5 mmol) obtained in step 1 was placed in a 500 ml eggplant flask and dissolved in 40 ml of tetrahydrofuran. In a nitrogen atmosphere, 10 ml of 1 M methylmagnesium bromide was added dropwise at 0 ° C., the temperature was raised to room temperature, and the mixture was stirred for 20 hours. After dropping 10 ml of 1M methylmagnesium bromide at room temperature again, the mixture was stirred for 12 hours, and 10 ml of 1M methylmagnesium bromide was further added and stirred for 1 hour. After completion of the reaction, the reaction solution was slowly poured into 50 ml of ice water, 40 ml of a 42% tetrafluoroboric acid aqueous solution was added, and the mixture was stirred at room temperature for 1 hour. After extraction with dichloromethane, it was dried over anhydrous magnesium sulfate to remove the solvent. The obtained solid was washed with hexane to obtain compound 1 (4.6 g, 15.2 mmol, 83%) as a vermilion solid.

<Step 3>
Compound 1 (3 g, 9.9 mmol) obtained in step 2 is placed in a 300 ml eggplant flask, dissolved in 80 ml of pyridine, and then malonaldehyde dianilide hydrochloride (1.3 g, 4.9 mmol) is added to reflux. The reaction was carried out under the conditions for 1 hour. After removing the solvent, the product was purified by column chromatography (ethyl acetate / dichloromethane) to isolate a brown solid (1.1 g, 2.0 mmol, yield 40%).

The obtained brown solid was identified by 1H NMR and confirmed to be a dye (A2-1B).

(2) Synthesis of dye (A2-1X1) A dye (A2-1X1) was synthesized according to the reaction pathway shown below.

<Step 1>
Compound 1 (4 g, 13.2 mmol) obtained by the same synthetic method as the dye (A2-1B) was placed in a 500 ml eggplant flask and dissolved in a mixed solvent of 25 ml of acetone and 40 ml of methanol. At room temperature, a potassium salt of bis (trifluoromethylsulfonyl) imide (5.5 g, 17.2 mmol) was added, the temperature was raised to 80 ° C., and the mixture was stirred. After completion of the reaction, the solvent was removed, water and dichloromethane were added, the target product was extracted, and the solvent was removed. The obtained solid was washed with hexane to obtain Compound 2 (5.68 g, 11.5 mmol).

<Step 2>
Compound 2 (3 g, 6.1 mmol) obtained in step 1 is placed in a 300 ml eggplant flask, dissolved in 100 ml of pyridine, and then malonaldehyde dianilide hydrochloride (0.8 g, 3.0 mmol) is added under reflux conditions. It was allowed to react for 1 hour below. After removing the solvent, it was purified by column chromatography (ethyl acetate / dichloromethane / methanol) to obtain a solid. The obtained solid was washed with a mixed solvent of ethyl acetate and hexane, and a brown solid (0.8 g, 1.1 mmol, yield 35%) was isolated.

The obtained brown solid was identified by 1H NMR and confirmed to be a dye (A2-1X1).

(3) Synthesis of dye (A2-2B) A dye (A2-2B) was synthesized according to the reaction pathway shown below.

<Step 1>
Compound 3 was synthesized according to the method described in Journal of the American Chemical Society, 133 (17), 6626-6635; 2011.

<Step 2>
Compound 1 (6 g, 19.9 mmol) obtained by the same synthetic method as the dye (A2-1B) and compound 3 (2.9 g, 9.9 mmol) obtained in step 1 are placed in a 500 ml eggplant flask and 200 ml. After dissolving in pyridine, the mixture was heated under reflux for 1 hour. After completion of the reaction, the solvent was concentrated and purified by column chromatography (ethyl acetate / dichloromethane) to obtain a solid. The obtained solid was reprecipitated with hexane / dichloromethane, and a brown solid (2.74 g, 4.7 mmol, 47% yield) was isolated.

The obtained brown solid was identified by 1H NMR and confirmed to be a dye (A2-2B).

(4) Synthesis of dye (A2-2X1) A dye (A2-2X1) was synthesized according to the reaction pathway shown below.

Compound 2 (3.0 g, 6.1 mmol) and compound 3 (0.92 g, 3.0 mmol) obtained by the same synthetic method as the dye (A2-1X1) were placed in a 500 ml eggplant flask and added to 60 ml of pyridine. After lysis, the mixture was heated under reflux for 1 hour. After completion of the reaction, the solvent was concentrated and purified by column chromatography (ethyl acetate / dichloromethane) to obtain a solid. The obtained solid was reprecipitated with hexane / dichloromethane to isolate a brown solid (1.2 g, 1.5 mmol, 51% yield).

The obtained brown solid was identified by 1H NMR and confirmed to be a dye (A2-2X1).

(5) Synthesis of dye (A2-3B) A dye (A2-3B) was synthesized according to the reaction pathway shown below.

<Step 1>
US Pat. Appl. Publ., 20070244330, 18 Oct 2007, Heterocycles, 24 (3), 755-69; Compound 4 was synthesized according to the method described in 1986.

<Step 2>
Compound 1 (3 g, 9.9 mmol) obtained by the same synthetic method as the dye (A2-1B) and compound 4 (1.4 g, 5.0 mmol) obtained in step 1 are placed in a 300 ml eggplant flask and 100 ml. After dissolving in pyridine, the mixture was heated under reflux for 1 hour. After completion of the reaction, the solvent was concentrated and purified by column chromatography (ethyl acetate / dichloromethane) to obtain a solid. The obtained solid was reprecipitated with hexane / dichloromethane, and a brown solid (1.4 g, 2.5 mmol, 50% yield) was isolated.

The obtained brown solid was identified by 1H NMR and confirmed to be a dye (A2-3B).

(6) Synthesis of dye (A2-4B) A dye (A2-4B) was synthesized according to the reaction pathway shown below.

<Step 1>
Compound 5 was synthesized according to the method described in PCT Int. Appl., 2012054367, 26 Apr 2012.

<Step 2>
Compound 1 (3 g, 9.9 mmol) obtained by the same synthetic method as the dye (A2-1B) and compound 5 (0.8 g, 4.9 mmol) obtained in step 1 are placed in a 300 ml eggplant flask and 100 ml. After dissolving in pyridine, a small amount of triethylamine was added, and the mixture was heated under reflux for 1 hour. After completion of the reaction, the solvent was concentrated and then purified by column chromatography (ethyl acetate / dichloromethane) to obtain a solid. The obtained solid was reprecipitated with hexane / dichloromethane, and a brown solid (1.0 g, 1.6 mmol, yield 31%) was isolated.

The obtained brown solid was identified by 1H NMR and confirmed to be a dye (A2-4B).

(7) Synthesis of dye (A2-5B) A dye (A2-5B) was synthesized according to the reaction pathway shown below.

The synthesis was carried out in the same manner as the dye (A2-4B) except that 4-bromophenylacetic acid was used instead of 4-methylphenylacetic acid to obtain a brown solid.

The obtained brown solid was identified by 1H NMR and confirmed to be a dye (A2-5B).

(8) Synthesis of dye (A2-6B) A dye (A2-6B) was synthesized according to the reaction pathway shown below.

In step 1 of the dye (A2-1B), N, N-dibutyl-3-aminophenol was used instead of N, N-diethyl-3-aminophenol, and the procedure up to step 2 was carried out in the same manner. Instead of, compound 7 was obtained. Dye (A2-6B) was obtained in the same manner except that compound 7 was used instead of compound 1 in step 2 of the dye (A2-3B).

The dye (A2-6B) was a brown solid, and its structure was confirmed by 1H NMR.

(9) Synthesis of dye (A1-1B) A dye (A1-1B) was synthesized according to the reaction pathway shown below.

<Step 1>
N-Methylformanilide (48.7 g, 0.36 mmol) was added to a 500 ml eggplant flask and dissolved in 50 ml dichloromethane, and then phosphoryl chloride (55 g, 1.36 mol) was added dropwise at 0 ° C. over 1 hour. After stirring at 0 ° C. for another 3 hours, cyclopentane-1-ene-1-ylbenzene (18.7 g, 0.13 mmol) was slowly added dropwise, the temperature was raised to 45 ° C., and the mixture was stirred for 20 hours. After adding 400 ml of water to the reaction solution, 50 g of potassium carbonate, 40 g of aniline chloride, and 50 g of potassium carbonate were added in this order at room temperature, and the mixture was stirred. 61%) was obtained.

<Step 2>
Compound 1 (4 g, 13.2 mmol) obtained in step 2 of the reaction pathway of the dye (A2-1B) and compound 8 (2.6 g, 6.6 mmol) obtained in step 1 above are placed in a 300 ml eggplant flask. It was added, dissolved in 130 ml of pyridine, and then heated to reflux for 1 hour. After completion of the reaction, the solvent was concentrated and then purified by column chromatography (ethyl acetate / dichloromethane) to obtain a solid. The obtained solid was reprecipitated with hexane / dichloromethane, and a brown solid (2.65 g, 3.9 mmol, yield 59%) was isolated.

The obtained brown solid was identified by 1H NMR and confirmed to be a dye (A1-1B).

(10) Synthesis of dye (A1-2B) A dye (A1-2B) was synthesized according to the reaction pathway shown below.

In step 1 of the reaction pathway of the dye (A1-1B), the reaction was carried out in the same manner except that 1-phenyl-1-cyclohexene was used instead of cyclopenta-1-ene-1-ylbenzene, and the reaction was carried out in the same manner. Got A dye (A1-2B) was obtained in the same manner except that compound 9 was used instead of compound 8 in step 2 of the method for synthesizing the dye (A1-1B).

The dye (A1-2B) was a brown solid and its structure was identified by 1H NMR.

<Optical characteristics>
The optical properties of dye (A) and other dyes for comparison were evaluated as follows. The results are shown in Table 10.
(In dichloromethane (DCM))
(1) λ _max [nm]
The maximum absorption wavelength λ _{max (A) DCM} at a spectral transmittance of 350 to 1200 nm was measured using a solution of the dye (A) in dichloromethane. Similarly, the maximum absorption wavelength λ _{max (O) DCM} of other dyes was measured.

(2) _Tave400-480 [%]
The spectral transmittance at a wavelength of 350 to 1200 nm was measured using a solution in which the dye (A) was dissolved in dichloromethane so that the transmittance in λ _{max (A) DCM} or λ _{max (O) DCM} was 10%. The average transmittance of light in the wavelength region of 400 to 480 nm was determined.

(In transparent resin)
As the transparent resin, the polyimide resin Neoprim (registered trademark) C3G30 (manufactured by Mitsubishi Gas Chemical Company, Inc., trade name), the acrylicimide resin PLEXIMID8817 (manufactured by Ebonic, trade name), and the polyester resin OKP-850 (trade name). The following optical characteristics were evaluated using SP3810 (manufactured by Teijin Co., Ltd., trade name), which is a polycarbonate resin (manufactured by Osaka Gas Chemical Company, Inc., trade name).

(1) Mass absorption coefficient [/ (cm · mass%)]
Each of the dye (A) prepared above and the other dyes for comparison was sufficiently stirred in a transparent resin and cyclohexanone and dissolved uniformly. The obtained solution was applied onto a glass plate (D263; manufactured by SCHOTT), and after drying, an absorption layer having a film thickness of 1.0 μm was obtained. The maximum mass absorption coefficient for light having a wavelength of 350 to 1200 nm was calculated by the above method.

(2) λ _max [nm]
In the same manner as above, a glass plate with an absorption layer having a film thickness of 1.0 μm was obtained. The spectral transmittance of the absorption layer was obtained by using the spectral transmittance of the glass plate with the absorption layer having a wavelength of 350 to 1200 nm and the spectral transmittance of the glass plate. The maximum absorption wavelength λ _{max (A) TR} (dye (A)) and the maximum absorption wavelength λ _{max (O) TR} (other dyes) were measured in the spectral transmittance.

(3) _Tave400-480 [%]
In the above, the amount of the dye (A) and other dyes added is adjusted so that the light transmittance at λ _{max (A) TR} (dye (A)) and λ _{max (O) TR} is 10% and absorbed. A layered glass plate was obtained. The spectral transmittance of the absorption layer was obtained by using the spectral transmittance of the glass plate with the absorption layer having a wavelength of 350 to 1200 nm and the spectral transmittance of the glass plate, and the average transmittance of light in the wavelength region of 400 to 480 nm was obtained.

[Examples 1 to 6]
For Examples 1 to 5, absorption layers shown in Table 11 were prepared on one main surface of a glass plate (D263; manufactured by SCHOTT, thickness; 0.21 mm). As the transparent resin, polyimide resin C3G30 (trade name; manufactured by Mitsubishi Gas Chemical Company) was used, and the film thickness of the absorption layer was 1 μm. The content of the dye in Table 11 is a mass portion with respect to 100 parts by mass of the transparent resin, and the addition amounts of the dye (A) or other dye and the dye (D) are λ _{max (A) TR and} λ respectively. The amount is adjusted so that the light transmittance at _{max (D) TR} is 10%. An optical filter was designed by designing a reflective layer having a near-infrared reflective region made of a dielectric multilayer film on the other main surface of the obtained glass plate with an absorbent layer. Examples 1 and 2 are examples, and examples 3 to 5 are comparative examples.

Further, as Example 6, a reflective layer having a near-infrared reflective region made of a dielectric multilayer film similar to Examples 1 to 5 is designed on one main surface of a glass plate (D263; manufactured by SCHOTT, thickness; 0.21 mm). It was used as an optical filter. The optical filter of Example 6 is a comparative optical filter composed of only a glass plate having no absorption layer and a dielectric multilayer film.

The optical characteristics of the reflective layer used are that the average transmittance of light in the wavelength region of 550 to 650 nm at an incident angle of 0 degrees is 94 [%], and the transmitted area of light in the wavelength region of 810 to 870 nm at an incident angle of 50 degrees. Was 61 [% nm], and the light transmittance in the wavelength region of 846 nm at an incident angle of 50 degrees was 6.4 [%].

With respect to the obtained optical filter, the spectral transmittance at a wavelength of 350 to 1200 nm was measured at an incident angle of 0 degrees, an incident angle of 30 degrees, and an incident angle of 50 degrees, and the following optical characteristics were evaluated. The results are shown in Table 11.

(I-1) Average transmittance in the wavelength region of 435 to 480 nm measured at an incident angle of 0 degrees.
(I-2) Average transmittance in the wavelength region of 703 to 739 nm measured at an incident angle of 0 degrees.
(I-3) Average transmittance in the wavelength region of 703 to 739 nm measured at an incident angle of 30 degrees.
(I-4) Absolute value of the value obtained by subtracting the average transmittance of 703 to 739 nm measured at an incident angle of 30 degrees from the average transmittance of 703 to 739 nm measured at an incident angle of 0 degrees.
(I-5) Transmittance at 846 nm measured at an incident angle of 0 degrees.
(I-6) Transmittance at 846 nm measured at an incident angle of 50 degrees.

The optical filter of the present invention maintains good transmission of visible light and has a near-red light in the wavelength range corresponding to that of absorbent glass, particularly in the wavelength range of 800 to 1050 nm, in terms of shielding property of near-infrared light. Since it is possible to achieve a high level of shielding of external light, it is useful for applications such as image pickup devices such as digital still cameras whose high performance has been increasing in recent years.

10A-10G ... Optical filter, 11 ... Absorption layer, 12 ... Reflective layer, 13 ... Transparent substrate, 14 ... Antireflection layer.

Claims (12)

An optical filter having an absorption layer containing a dye (A) represented by the following formula (A1) or (A2) and a transparent resin .

However, the symbols in the formulas (A1) and (A2) are as follows.
R ¹⁰¹ to R ¹⁰³ , R ¹⁰⁵ to R ¹⁰⁹ , R ¹¹¹ to R ¹¹³ , and R ¹¹⁵ to R ¹¹⁷ are independently hydrogen atoms, halogen atoms, sulfo groups, hydroxyl groups, cyano groups, nitro groups, and carboxy groups. A phosphate group, an alkyl group having 1 to 10 carbon atoms which may have a substituent, an alkoxy group or an acyloxy group, or -NR ¹²⁸ R ¹²⁹ (R ¹²⁸ and R ¹²⁹ are independently hydrogen atoms or or It is an alkyl group having 1 to 15 carbon atoms which may have a substituent). R ¹⁰² and R ¹⁰³ , R ¹⁰⁶ and R ¹⁰⁷ , R ¹¹² and R ¹¹³ , and R ¹¹⁶ and R ¹¹⁷ may be connected to each other to form a ring having 5 to 8 members.
R ¹⁰⁴ and R ¹¹⁴ are -NR ¹²⁸ R ¹²⁹ (R ¹²⁸ and R ¹²⁹ are alkyl groups having 1 to 15 carbon atoms, one of which may have a hydrogen atom or a substituent, and the other having a substituent. It may be an alkyl group having 1 to 15 carbon atoms.).
R ¹¹⁰ and R ¹¹⁸ represent a halogen atom or an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 30 carbon atoms which may have a substituent.
Equations (A1) and ( ^A2 ) optionally have ^Z1 and Z2. Z ¹ and Z ² are 5-membered or 6-membered rings.
X ^- is a monovalent anion and is represented by I- ^, BF _4- ^, PF _6- ^, ClO 4- _, ^the following formula (X1), or (X2). m1 and m2 indicate the number of X ⁻ , which is 1 .

The optical filter according to claim 1, wherein the dye (A) has a maximum mass extinction coefficient of 1500 / (cm · mass%) or more in light having a wavelength of 350 to 1200 nm when contained in the transparent resin. The dye (A) according to claim 1 or 2 , wherein the dye (A) has a maximum absorption wavelength λ _{max (A) DCM} in a wavelength region of 800 to 1050 nm in a spectral transmittance of a wavelength of 350 to 1200 nm measured by dissolving in dichloromethane. Optical filter. The dye (A) has a wavelength of 400 to 480 nm at a spectral transmittance of 350 to 1200 nm, which is measured by dissolving the dye (A) in dichloromethane so that the transmittance at the maximum absorption wavelength λ _{max (A) DCM} is 10%. The optical filter according to any one of claims 1 to 3 , wherein the average transmittance of light in the region T _{400-480ave (A) DCM} is 95% or more. The dye (A) is a transparent resin so that the transmittance is 10% at the maximum absorption wavelength λ _{max (A) TR} obtained from the spectral transmittance having a wavelength of 350 to 1200 nm measured by containing the dye (A). The optical filter according to any one of claims 1 to 4, wherein the average transmittance T _{400-480ave (A) TR} of light in the wavelength region of 400 to 480 nm measured contained in is 82% or more. The transparent resin includes polyester resin, acrylic resin, epoxy resin, en-thiol resin, polycarbonate resin, polyether resin, polyarylate resin, polysulfone resin, polyether sulfone resin, polyparaphenylene resin, and polyarylene ether phosphine oxide. The optical device according to any one of claims 1 to 5 , which comprises at least one selected from a resin, a polyamide resin, a polyimide resin, a polyamideimide resin, a polyolefin resin, a cyclic olefin resin, a polyurethane resin, an acrylicimide resin and a polystyrene resin. filter. The optical filter according to claim 6, wherein the transparent resin comprises at least one selected from a polyester resin, a polycarbonate resin, a polyimide resin, and an acrylicimide resin. The absorption layer further comprises a dye (D) having a maximum absorption wavelength λ _{max (D) DCM} at a wavelength of 350 to 1200 nm as measured by a solution dissolved in dichloromethane at a wavelength of 350 to 1200 nm. The optical filter according to any one of 7 to 7 . The optical filter according to any one of claims 1 to 8 , further comprising a reflective layer made of a dielectric multilayer film. The optical filter according to any one of claims 1 to 9 , further comprising a transparent substrate and the absorption layer on the transparent substrate. An image pickup apparatus comprising the optical filter according to any one of claims 1 to 10 . A dye represented by the following formula (A1) or (A2).

However, the symbols in the formulas (A1) and (A2) are as follows.
R ¹⁰¹ to R ¹⁰³ , R ¹⁰⁵ to R ¹⁰⁹ , R ¹¹¹ to R ¹¹³ , and R ¹¹⁵ to R ¹¹⁷ are independently hydrogen atoms, halogen atoms, sulfo groups, hydroxyl groups, cyano groups, nitro groups, and carboxy groups. A phosphate group, an alkyl group having 1 to 10 carbon atoms which may have a substituent, an alkoxy group or an acyloxy group, or -NR ¹²⁸ R ¹²⁹ (R ¹²⁸ and R ¹²⁹ are independently hydrogen atoms or or It is an alkyl group having 1 to 15 carbon atoms which may have a substituent). R ¹⁰² and R ¹⁰³ , R ¹⁰⁶ and R ¹⁰⁷ , R ¹¹² and R ¹¹³ , and R ¹¹⁶ and R ¹¹⁷ may be connected to each other to form a ring having 5 to 8 members.
R ¹⁰⁴ and R ¹¹⁴ are -NR ¹²⁸ R ¹²⁹ (R ¹²⁸ and R ¹²⁹ are alkyl groups having 1 to 15 carbon atoms, one of which may have a hydrogen atom or a substituent, and the other having a substituent. It may be an alkyl group having 1 to 15 carbon atoms.).
R ¹¹⁰ and R ¹¹⁸ indicate an aryl group having 6 to 30 carbon atoms which may have a substituent.
Equations (A1) and ( ^A2 ) optionally have ^Z1 and Z2. Z ¹ and Z ² are 5-membered or 6-membered rings.
X ^- is a monovalent anion and is represented by I- ^, BF _4- ^, PF _6- ^, ClO 4- _, ^the following formula (X1), or (X2). m1 and m2 indicate the number of X ⁻ , which is 1 .

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