JP2019078816A - Optical filter and imaging apparatus - Google Patents

Abstract

To provide an optical filter having excellent light-shielding property against near infrared light, suppressing incident angle dependency for light incident at a high angle, particularly, reducing light leakage in a wavelength region of 800 to 900 nm at a high incident angle, and having a high transmittance of visible light and excellent light fastness, and an imaging apparatus excellent in color reproducibility using the above optical filter.SOLUTION: The optical filter has an absorption layer containing a squarylium dye (X) described below and a transparent resin, and a reflection layer comprising a dielectric multilayer film. The squarylium dye shows a molar absorptivity of 150000 [L/(mol cm)] or more in dichloromethane and a maximum absorption wavelength λof 800 to 870 nm, and in a spectral transmittance curve measured at a concentration that gives a transmittance of 10% at λ, an average transmittance from 550 to 650 nm is 90% or more and an average transmittance from 830 to 900 nm is 65% or less.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an optical filter that transmits visible light and blocks near infrared light, and an imaging device provided with the optical filter.

  In an imaging apparatus using a solid-state imaging device, light in the visible range (hereinafter also referred to as "visible light") is transmitted and light in the near infrared range (hereinafter, "near red" is obtained in order to reproduce color tone well and obtain clear images. An optical filter for blocking external light) is used. As such an optical filter, there is known a near-infrared cut filter including an absorption layer containing a near-infrared absorption dye and a reflection layer composed of a dielectric multilayer film that blocks near-infrared light (for example, a patent) Reference 1). That is, since the spectral transmittance curve of the dielectric multilayer film itself changes depending on the incident angle, the near infrared cut filter including both the reflection layer and the absorption layer has the incidence angle dependency suppressed by the absorption characteristics of the absorption layer. A spectral transmission curve is obtained.

  However, in recent years, with the miniaturization of imaging devices, there is a demand to suppress the incidence angle dependency to light incident at a higher angle, for example, 50 degrees or more. In Patent Document 1, a near infrared cut filter that can sufficiently cope with an incident angle of 30 degrees is obtained. For example, when the incident angle is increased to about 50 degrees, the wavelength range of 800 to 900 nm in the near infrared range is obtained. There is a problem of light leakage or the like where a region where the light transmittance is high appears.

JP, 2011-100084, A

  The present invention is excellent in the near infrared light shielding property and can suppress the incident angle dependency to light incident at a high angle, and in particular, can reduce light leakage in the wavelength range of 800 to 900 nm at a high incident angle. An object of the present invention is to provide an optical filter which has a high visible light transmittance and is excellent in light resistance, and an imaging device which is excellent in color reproducibility using the optical filter.

The present invention provides an optical filter having an absorption layer containing a squarylium dye (X) having the following characteristics (1) to (4) and a transparent resin, and a reflection layer formed of a dielectric multilayer film.
(1) When it is made to melt | dissolve in a dichloromethane, the molar absorption coefficient in the light of wavelength 350-1200 nm is 150000 [L / (mol * cm)] or more.
(2) In a spectral transmittance curve at a wavelength of 400 to 1100 nm measured with a solution dissolved in dichloromethane, the maximum absorption wavelength λ _max -DCM _(X) is in a wavelength range of 800 to 870 nm.
(3) 550 to 650 nm in a spectral transmittance curve at a wavelength of 400 to 1100 nm, which is measured with a solution dissolved in dichloromethane such that the light transmittance in the maximum absorption wavelength λ _max -DCM _(X) is 10% The average transmittance of light is 90% or more.
(4) In a spectral transmittance curve of wavelength 400 to 1100 nm measured with a solution dissolved in dichloromethane so that the transmittance of light at maximum absorption wavelength λ _max -DCM _(X) is 10%, 830 to 900 nm The average transmittance of light is 65% or less.

  The present invention also provides an imaging device provided with the optical filter of the present invention.

  According to the present invention, it is possible to suppress the incident angle dependency on light incident at a high angle. In particular, it is possible to provide an optical filter capable of reducing light leakage in a wavelength range of 800 to 900 nm at a high incident angle, having a high visible light transmittance, and being excellent in light resistance. Furthermore, according to the present invention, it is possible to provide an imaging device excellent in color reproducibility using the optical filter.

It is a sectional view showing roughly an example of an optical filter of an embodiment. It is a sectional view showing roughly another example of the optical filter of an embodiment.

Hereinafter, embodiments of the present invention will be described.
In the present specification, near infrared absorbing dyes may be abbreviated as “NIR dyes” and ultraviolet absorbing dyes may be abbreviated as “UV dyes”.
In the present specification, an NIR dye consisting of a compound represented by formula (I) is also referred to as NIR dye (I), and the same applies to other dyes (for example, from a compound represented by formula (I-1) described below) (Also referred to as NIR dye (I-1)). Further, for example, a group represented by the formula (Ar1) is also referred to as a group (Ar1), and the same applies to groups represented by other formulas.

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

In the present specification, the squarylium dye means a dye having a squarylium skeleton represented by the following formula (S1) which can have a resonance structure represented by the following formula (S2) in the structural formula. In the present specification, the squalilium skeleton is represented by either the formula (S1) or the formula (S2).

<Optical filter>
The optical filter of the embodiment of the present invention (hereinafter, also referred to as "the present filter") is also referred to as squalilium dye (X) (hereinafter, referred to as "the dye (X)") having the following characteristics (1) to (4). And a transparent resin, and a reflective layer made of a dielectric multilayer film. In the following description, the “reflection layer” refers to a reflection layer made of a dielectric multilayer film.

(1) When it is made to melt | dissolve in a dichloromethane, the molar absorption coefficient in the light of wavelength 350-1200 nm is 150000 [L / (mol * cm)] or more. Hereinafter, unless otherwise noted, the “molar absorption coefficient” of the dye is the molar absorption coefficient in light of a wavelength of 350 to 1200 nm when dissolved in dichloromethane.
(2) In a spectral transmittance curve at a wavelength of 400 to 1100 nm measured with a solution dissolved in dichloromethane, the maximum absorption wavelength λ _max -DCM _(X) is in a wavelength range of 800 to 870 nm.
(3) 550 to 650 nm in a spectral transmittance curve at a wavelength of 400 to 1100 nm, which is measured with a solution dissolved in dichloromethane such that the light transmittance in the maximum absorption wavelength λ _max -DCM _(X) is 10% The average transmittance of light in the wavelength range of 90% or more.
(4) In a spectral transmittance curve of wavelength 400 to 1100 nm measured with a solution dissolved in dichloromethane so that the transmittance of light at maximum absorption wavelength λ _max -DCM _(X) is 10%, 830 to 900 nm The average transmittance of light in the wavelength region of is less than 65%.

  In the filter, the absorption layer contains the dye (X) having the characteristics (1) to (4), so that the light-shielding property of near-infrared light is excellent, and the transmittance of visible light is high. Furthermore, this enables the present filter to suppress the incident angle dependency to light incident at a high angle, which is caused by having a reflective layer, and in particular, light leakage in the wavelength range of 800 to 900 nm at high incident angles. It can be reduced. In addition, the present filter is excellent in light resistance as the dye (X) is a compound having a squarylium skeleton.

The dye (X) preferably further has the following properties (5) to (8).
(5) The mass absorption coefficient in light of 350 to 1200 nm in wavelength when contained in the transparent resin is 2000 / (cm · mass%) or more.
(6) In the spectral transmittance curve of the wavelength of 400 to 1100 nm measured by being contained in the transparent resin, the maximum absorption wavelength λ _{max -RE (X)} is in the wavelength range of 800 to 870 nm.
(7) 550 to 650 nm in a spectral transmittance curve of a wavelength of 400 to 1100 nm, which is measured to be contained in a transparent resin so that the transmittance of light at the maximum absorption wavelength λ _{max-RE (X)} is 10%. The average transmittance of light in the wavelength region is 90% or more.
(8) The spectral transmittance curve of the wavelength 400 to 1100 nm, which is measured to be contained in the transparent resin so that the transmittance of light at the maximum absorption wavelength λ _{max-RE (X)} is 10%, is 830 to 900 nm The average transmittance of light in the wavelength region is 65% or less.

  That is, it is preferable that the dye (X), even in combination with the transparent resin used for the absorption layer, has the same optical properties as when it is dissolved in dichloromethane. In addition, as for the film thickness of the pigment | dye (X) containing transparent resin layer used for measurement of the characteristic of (5)-(8), about 1.0 micrometer is preferable. The transparent resin to be used may satisfy the requirements for transparency described later.

In addition, the mass extinction coefficient is the internal transmittance T [%] of light at the maximum absorption wavelength in the wavelength range of 350 to 1200 nm (= actual transmittance [%] / (100-actual reflectance [%]) x 100 [ %]) Can be calculated by −log ₁₀ (T / 100). Hereinafter, unless otherwise specified, the "mass extinction coefficient" of the dye is the mass extinction coefficient calculated by the above method.

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

  The filter may also have other functional layers. As another functional layer, the reflection prevention layer which suppresses the transmittance | permeability loss of visible light is mentioned, for example. In particular, when the absorption layer has the outermost surface configuration, a visible light transmittance loss due to reflection occurs at the interface between the absorption layer and air, and therefore, it is preferable to provide an antireflection layer on the absorption layer.

  Next, a configuration example of the present filter will be described using the drawings. FIG. 1 is a configuration example of an optical filter 10A provided with a reflective layer 12 on one main surface of the absorption layer 11. As shown in FIG. In the optical filter 10A, the absorption layer 11 can be formed of a layer containing a dye (X) and a transparent resin. Note that “providing the reflective layer 12 on one main surface (upper side) of the absorbing layer 11” is not limited to the case where the reflecting layer 12 is provided in contact with the absorbing layer 11, and the absorbing layer 11 and the reflective layer 12 The following configuration is also the same, including the case where another functional layer is provided between

  FIG. 2 is a cross-sectional view schematically showing an example of an optical filter of an embodiment having a transparent substrate, an absorption layer, and a reflection layer. The optical filter 10 B has a transparent substrate 13, an absorption layer 11 disposed on one of the principal surfaces of the transparent substrate 13, and a reflective layer 12 provided on the other principal surface of the transparent substrate 13. In the optical filter 10B, the absorption layer 11 can be formed of a layer containing a dye (X) and a transparent resin. The optical filter 10B further has an antireflection layer 14 on the main surface of the absorbing layer 11 on the opposite side to the transparent substrate 13.

Hereinafter, the absorption layer, the reflection layer, the transparent substrate, and the antireflective layer will be described.
(Absorbent layer)
The absorbing layer contains a dye (X) having the above-mentioned properties (1) to (4), preferably further having the above-mentioned properties (5) to (8), and a transparent resin.

  The absorbing layer is typically a layer or (resin) substrate in which the dye (X) is uniformly dissolved or dispersed in a transparent resin. The absorbing layer may contain other NIR dyes in addition to the dye (X) as long as the effects of the present invention are not impaired. Furthermore, the absorbing layer may contain a dye other than the NIR dye, particularly a UV dye, as long as the effects of the present invention are not impaired.

As other NIR dyes, it is preferable to contain a dye (A) satisfying the requirements of the following (iii-1).
(Iii-1) A spectral transmittance curve at a wavelength of 400 to 1100 nm measured with a solution dissolved in dichloromethane, having a maximum absorption wavelength λ _max -DCM _(A) at 600 to 750 nm.

Furthermore, it is preferable that the dye (A) satisfies the following requirement (iii-2).
(Iii-2) 550 in a spectral transmittance curve at a wavelength of 400 to 1100 nm, which is measured in a solution dissolved in dichloromethane so that the light transmittance in the maximum absorption wavelength λ _max -DCM _(A) is 10%. The average transmittance in the wavelength region of light of -650 nm is 90% or more.

In the optical absorption spectrum of the dye (A), the absorption peak having an apex of the absorption in the λ _{max-DCM (A) (hereinafter,} referred to as "absorption peak of λ _{max-DCM (A)"),} the visible light side The slope should be steep. Furthermore, the absorption peak of λ _{max -DCM (A)} may have a gentle slope on the long wavelength side.

[Pigment (X)]
Dye (X) is a dye having a squarylium skeleton structure having the properties of (1) to (4). About (1), 250000 [L / (mol * cm)] or more is preferable, and 270000 [L / (mol * cm)] or more is more preferable. Regarding (2), the maximum absorption wavelength λ _max -DCM _(X) is preferably in the wavelength range of 815 to 860 nm, and more preferably in the wavelength range of 825 to 860 nm. About (3), 93% or more is preferable and, as for the average transmittance | permeability of the light in a 550-650 nm wavelength range, 95% or more is more preferable. About (4), 50% or less is preferable and, as for the average transmittance | permeability of the light in a wavelength region of 830-900 nm, 45% or less is more preferable.

The dye (X) is more preferably a dye having the properties of (5) to (8). With regard to (5), the mass extinction coefficient is preferably 3000 [/ (cm · mass%)] or more, and more preferably 3300 [/ (cm · mass%)] or more. Regarding (6), the maximum absorption wavelength λ _{max -RE (X)} is preferably in the wavelength range of 825 to 870 nm, and more preferably in the wavelength range of 835 to 870 nm. About (7), 90% or more is preferable and, as for the average transmittance | permeability in a 550-650 nm wavelength range, 95% or more is more preferable. About (8), 65% or less is preferable and, as for the average transmittance | permeability in a wavelength range of 830-900 nm, 30% or less is more preferable.

  Specifically as a pigment | dye (X), the compound shown by the following formula (X-1) which can take a resonance structure is mentioned. Specifically as a resonance structure of compound (X-1), the compound shown by following formula (X-1 ') or (X-1' ') is mentioned.

However, in the formula (X-1), each of A is a group which may have a substituent and which has a monocyclic to tricyclic aromatic ring of 5 to 6 members as a skeleton. The aromatic ring may contain one or more hetero atoms selected from N, S, O and Se, n is independently 0 or 1, and R ¹⁰¹ is independently substituted. It is also a good hydrogen atom. The aromatic ring (Ar) is also referred to hereinafter as an aromatic ring which may contain one or more hetero atoms selected from a monocyclic to tricyclic N, S, O and Se each having 5 to 6 ring members. .

  Hereinafter, unless otherwise specified, the compound (X-1) includes the compound (X-1 ′) and the compound (X-1 ′ ′) The same applies to other squarylium dyes.

In compound (X-1), A, n and R ¹ may be different or the same at the left and right of the squarylium skeleton. From the viewpoint of production, A, n and R ¹⁰¹ are preferably identical on the left and right of the squarylium skeleton.

  Each of the groups A is a group having an aromatic ring (Ar) as an optionally substituted substituent as a backbone, and a bond directly or via a methine group to a squarylium ring forms one of the carbons constituting the ring. It has an atom.

  The aromatic ring (Ar) may be an aromatic compound in which 1 to 5 rings having 5 to 6 members are bonded to each other, and may contain one or more hetero atoms selected from N, S, O and Se. Good. The aromatic ring (Ar) preferably contains a hetero atom as a constituent element of the ring, and the hetero atom is preferably N or O. The number of rings is more preferably 2 or 3.

  Specific examples of the aromatic ring (Ar) include benzene ring, indazole ring, imidazole ring, benzoimidazole ring, thiazole ring, benzothiazole ring, oxazole ring, pyridine ring, quinoline ring, indoline ring, pyran ring, thiopyran ring And selenopyran ring, benzopyran ring, benzothiopyran ring, benzoselenopyran ring, benzoindole ring and the like. In addition, when an aromatic ring (Ar) becomes a group, the position of the double bond may move in the ring. In addition, the number of hydrogen atoms bonded to the atoms constituting the ring may change accordingly. The group having an aromatic ring (Ar) as a skeleton also includes such a case. For example, the following group (Ar 8) is included in a group having a quinoline ring as a skeleton.

As a substituent which can substitute the hydrogen atom which an aromatic ring (Ar) has, it is C1-C10 which may have a halogen atom, a substituent (a halogen atom, or a C1-C10 alkoxy group), for example Alkyl group or alkoxy group, acyloxy group having 1 to 10 carbon atoms, sulfo group, hydroxyl group, cyano group, nitro group, carboxy group, phosphoric acid group, -NR ¹⁰⁸ R ¹⁰⁹ (R ¹⁰⁸ and R ¹⁰⁹ are each independently A hydrogen atom, a substituent having 1 to 15 carbon atoms (a halogen atom or an alkoxy group having 1 to 10 carbon atoms, R ¹⁰⁸ and R ¹⁰⁹ are linked to each other to form a heterocyclic ring having 5 or 6 members with a nitrogen atom And the like) or an alkyl group which may have one).

  In the present specification, unless otherwise specified, the alkyl group may be linear, branched, cyclic or a structure combining these structures.

  When n is 0, the group A is directly attached to the squarylium ring. When n is 0, the group A may have a substituent among the above-mentioned, benzene ring, indazole ring, imidazole ring, benzimidazole ring, thiazole ring, benzothiazole ring, oxazole ring, pyridine ring, quinoline ring And groups having an indoline ring as a skeleton are preferred. Hereinafter, "a group having a benzene ring as a skeleton" includes a group having a hydrogen atom substituted and having a benzene ring as a skeleton. The same applies to other aromatic rings (Ar).

  From the viewpoint of resin solubility and synthesis, a group having an aromatic ring represented by the following formulas (Ar1) to (Ar4) as a skeleton is preferable.

In the formula (Ar2), ... X ^b ... means that the presence of X ^b is optional. In formula (Ar2), X ^a and X ^b independently represent an alkylene group having 2 or 3 carbon atoms. In formulas (Ar3) and (Ar4), ^Xc and ^Xd independently represent an alkylene group having 1 or 2 carbon atoms.

  When n is 1, the group A is preferably a group having an aromatic ring represented by the following formulas (Ar5) to (Ar9) as a skeleton among the above, and from the viewpoint of solubility and absorption wavelength, the group (Ar6 And groups (Ar7) and (Ar9) as a skeleton are preferable, and a group having a group (Ar9) as a skeleton is particularly preferable.

  As the compound (X-1), a compound represented by the following formula (X-11), in which n is 1 and A is a group having the group (Ar 9) as a skeleton, has long wavelength absorption, solubility and synthesis It is preferable in terms of the simplicity of

However, the symbols in formula (X-11) are as follows.
R ¹⁰¹ each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms which may have a substituent. As a substituent, a halogen atom and a C1-C10 alkoxy group are mentioned. From the viewpoint of production, R ¹⁰¹ is preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms which may have a substituent, and more preferably a hydrogen atom, a methyl group or an ethyl group.

R ¹⁰² , R ¹⁰³ and R ^{105 to} R ¹⁰⁷ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms which may have a substituent, a sulfo group, a hydroxyl group or a cyano group , A nitro group, a carboxy group, a phosphoric acid group, and -NR ¹⁰⁸ R ¹⁰⁹ (R ¹⁰⁸ and R ¹⁰⁹ each independently represent a hydrogen atom or an alkyl group which may have a substituent having 1 to 15 carbon atoms ). As a substituent, a halogen atom and a C1-C10 alkoxy group are mentioned.

Each of R ¹⁰² , R ¹⁰³ and R ^{105 to} R ¹⁰⁷ is preferably independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, from the viewpoint of easiness of synthesis. R ¹⁰⁶ and R ¹⁰⁷ are preferably alkyl groups having 1 to 10 carbon atoms, more preferably secondary or tertiary branched alkyl groups having 10 or less carbon atoms, from the viewpoint of solubility in a transparent resin and a solvent, and Tasha More preferred are a butyl group, an isopropyl group and an isobutyl group.

R ¹⁰⁴ each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms or an alkoxy group, an acyloxy group having 1 to 10 carbon atoms, -NR ¹⁰⁸ R ¹⁰⁹ (R ¹⁰⁸ and R ¹⁰⁹ are And each independently represents a hydrogen atom or an alkyl group which may have a substituent having 1 to 15 carbon atoms (a halogen atom or an alkoxy group having 1 to 10 carbon atoms).

R ¹⁰⁴ is preferably —NR ¹⁰⁸ R ^{109 because it} is easy to adjust λ _{max -DCM (X)} within the above range and to easily increase the molar absorption coefficient. In that case, each of R ¹⁰⁸ and R ¹⁰⁹ is preferably independently an alkyl group having 1 to 15 carbon atoms, and from the viewpoint of solubility in a transparent resin or a solvent, linear or branched carbon atoms having 1 to 1 carbon atoms 15 alkyl groups are preferred.

More specific examples of the compound (X-11) include the compounds shown in Tables 1 and 2 below. In all of the compounds shown in Tables 1 and 2, R ^{101 to} R ¹⁰⁷ are the same on the left and right of the squarylium skeleton.

  Among these, as a compound (X-11), a compound (X-11-1), a compound (X-11-3), and a compound (X-11-4) are preferable.

Compound (X) can be produced, for example, as shown in reaction route (F1) for obtaining compound (e) in which R ¹⁰⁴ is —NR ¹⁰⁸ R ¹⁰⁹ in the following compound (X-11). In the reaction pathway (F1), Me represents a methyl group, and Et represents an ethyl group. The same applies to other formulas.

<Step 1>
The compound (b) is added to a phenol (a) having an amino group substituted by R ¹⁰⁸ and R ¹⁰⁹ at the 3-position, and the mixture is heated and stirred. After completion of the reaction, the reaction solution is cooled to room temperature, ethyl acetate and 0.5 M hydrochloric acid are added, and then extracted with hexane and ethyl acetate. After removal of the solvent, the brown oil is isolated as compound (c) by flash column chromatography (hexane / ethyl acetate).

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

<Step 3>
Compound (d) obtained in Step 2 is dissolved in 1-butanol, and triethylamine-dicyanoalkene squarate (e) is synthesized with reference to US Patent Application Publication No. 2005/0202565 to promote reaction. Add quinoline as a base of and stir under reflux conditions. After filtering the reaction solution, the obtained brown solid is purified by flash column chromatography (methanol / dichloromethane) to obtain the desired compound (f) as a brown solid.

  Dye (X) may consist of 1 type of compounds, and may consist of 2 or more types of compounds. When it consists of 2 or more types of compounds, each compound does not necessarily have the property of pigment (X), and it may have the property of pigment (X) as a mixture.

[Pigment (A)]
As the dye (A), cyanine dye, phthalocyanine dye, naphthalocyanine dye, dithiol metal complex dye, diimonium dye, polymethine dye satisfying the requirements of (iii-1), preferably further satisfying the requirements of (iii-2) And at least one dye selected from the group consisting of phthalide dyes, naphthoquinone dyes, anthraquinone dyes, indophenol dyes, and squalilium dyes.

Among these, squarylium dyes which satisfy the requirement of (iii-1), preferably satisfy the requirement of (iii-2) are particularly preferred. The dye (A) composed of squarylium dye has low absorption of visible light in the above absorption spectrum, and the absorption peak of λ _{max -DCM (A)} has a steep slope on the visible light side, while having storage stability and to light High stability.

As the squarylium dye (A), compounds represented by any one of formulas (I) to (III) in which λ _max -DCM _(A) is in the wavelength range of 600 to 750 nm are preferred. Moreover, as for a pigment | dye (A), 1000 / (cm * mass%) or more is preferable, and the mass extinction coefficient when it makes a transparent resin contain is more preferable 1500 / (cm * mass%) or more.

However, the symbols in formula (I) are as follows.
R ²⁴ and R ²⁶ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms or an alkoxy group, an acyloxy group having 1 to 10 carbon atoms, -NR ²⁷ R ²⁸ (R ²⁷ and R ²⁸ each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or —C (OO) —R ²⁹ (R ²⁹ represents a hydrogen atom or one carbon atom which may have a substituent) An alkyl group of 20 to 20, an aryl group of 6 to 11 carbon atoms, or an aryl group of 7 to 18 carbon atoms which may have a substituent and may have an oxygen atom between carbon atoms), NHR ³⁰ or —SO ₂ —R ³⁰ (wherein each of R ³⁰ may be substituted with one or more hydrogen atoms with a halogen atom, a hydroxyl group, a carboxy group, a sulfo group, or a cyano group; Not Sum bond, an oxygen atom, a hydrocarbon group) saturated or may 1 to 25 carbon atoms which contain an unsaturated ring structure.), Or a group ^{(R 41, R 42} represented by the following formula (S) is And independently represent a hydrogen atom, a halogen atom, or an alkyl group or alkoxy group having 1 to 10 carbon atoms, where 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, heterocycle B, and heterocycle C having 5 or 6 members, respectively, together with the nitrogen atom It is also good.
R ²¹ and R ²² in the case where the heterocycle A is formed are an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, or a hydrogen atom having 1 to 6 carbon atoms as a divalent group -Q- to which they are bonded The alkylene group which may be substituted by the C1-C10 acyloxy group which may have a substituent, or an alkylene oxy group 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 respectively a divalent group -X ¹ -Y ¹ -and-to which they are bonded. X ¹ and X ² each represent a group represented by the following formula (1x) or (2x) as X ² -Y ^2- (where nitrogen is bound to X ¹ and X ² ), and Y ¹ and Y ² each represent It is a group represented by any one selected from the following formulas (1y) to (5y). When X ¹ and X ² are each a group represented by the following formula (2x), Y ¹ and Y ² may each be a single bond, and in that case, they may have an oxygen atom between carbon atoms .

In the formula (1x), four Z's each independently represent a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms or an alkoxy group, or —NR ³⁸ R ³⁹ (R ³⁸ and R ³⁹ are each independently And represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms). R ^{31 to} R ³⁶ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms, and R ³⁷ represents 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 not forming a heterocyclic ring, and R ²⁵ are each bonded to any one of these to form a 5-membered ring Alternatively, it may form a 6-membered ring. R ³¹ and R ³⁶ , and R ³¹ and R ³⁷ may be directly bonded.
When not forming a heterocycle, R ²¹ and R ²² each independently represent a hydrogen atom, an alkyl or allyl group having 1 to 6 carbon atoms which may have a substituent, or a substituent The C6-C11 aryl group which may have, or an aryl group is shown. When not forming a heterocyclic ring, R ²³ and R ²⁵ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms or an alkoxy group.

However, the symbols in formula (II) are as follows.
Each of the rings Z is independently a 5- or 6-membered ring which has 0 to 3 hetero atoms in the ring and which may be substituted.
The carbon atoms or heteroatoms constituting R ¹ and R ² , R ² and R ³ , and R ¹ and ring Z are linked to each other to form a heterocycle A 1, a heterocycle B 1 and a heterocycle C 1 together with the nitrogen atom R ¹ and R ² each independently represent a hydrogen atom, a halogen atom, or an unsaturated bond, a hetero atom, a saturated or unsaturated group between carbon atoms. A hydrocarbon group which may have a ring structure and may have a substituent is shown, and R ³ and R ⁴ may each independently contain a hydrogen atom, a halogen atom, or a heteroatom between carbon atoms Indicates an alkyl group or an alkoxy group.

However, the symbols in formula (III) are as follows.
R ⁵¹ each independently represents a halogen atom, or an alkyl group having 1 to 3 carbon atoms which may have a substituent,
R ^{52 to} R ⁵⁸ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms which may have a substituent.
R ⁵² and R ⁵³ may be linked 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 is an alkyl having 1 to 10 carbon atoms It may be substituted by 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 by an alkyl group having 1 to 10 carbon atoms.

  As a compound (I), the compound shown by either of Formula (I-1)-(I-4) is mentioned, for example.

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

  Among the compounds (I-1) to (I-4), as the dye (A), compounds (I-1) to (I-3) are preferable 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 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 the compound (I-1), R ²¹ independently represents the formula (I) from the viewpoint of solubility, heat resistance, and steepness of change near the boundary between the visible region and the near infrared region in the spectral transmittance curve. The group represented by 4-1) or (4-2) is more preferable.

R < ⁷¹ > -R < ⁷⁵ > shows independently a hydrogen atom, a halogen atom, or a C1-C4 alkyl group in Formula (4-1) and Formula (4-2).

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

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

In 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 The C7-C18 aryl group which may have a substituent and may have an oxygen atom between carbon atoms is preferable. As a substituent, 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, an alkoxy group having 1 to 6 carbon atoms And an acyloxy group having 1 to 6 carbon atoms.

As R ²⁹ , a linear, branched or cyclic alkyl group having 1 to 17 carbon atoms, a fluoroalkyl group having 1 to 6 carbon atoms and / or 1 to 6 carbon atoms which may be substituted with a fluorine atom A phenyl group which may be substituted by an alkoxy group, and an alkyl which may have an oxygen atom between carbon atoms and which may have an oxygen atom and which may be substituted at the terminal with a fluorine atom having a carbon number of 1 to 6 A group selected from a group and / or an aryl group having a phenyl group which may be substituted with 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 an unsaturated bond between carbon atoms, an oxygen atom, a saturation or A group which is a C5-C25 hydrocarbon group 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 specific examples of the compound (I-11) include the compounds shown in Table 3 below. In addition, in Table 3, group (11-1) is shown as (11-1). The same applies to other groups. The designations of groups in the other tables below are the same. Moreover, as for the compounds shown in Table 3, the meanings of the respective symbols are the same on the left and right of the squarylium skeleton. The same applies to squarylium dyes shown in the other tables below.

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

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

In the compound (I-12), R ³⁰ independently represents an alkyl or alkoxy group having 1 to 12 carbon atoms which may have a branch, or a carbon number having an unsaturated ring structure from the viewpoint of light resistance 6 to 16 hydrocarbon groups are preferred. The unsaturated ring structure includes benzene, toluene, xylene, furan, benzofuran and the like. R ³⁰ is independently more preferably an alkyl or alkoxy group having 1 to 12 carbon atoms which may have a branch. In each group showing R ³⁰ , a part or all of hydrogen atoms may be substituted by a halogen atom, particularly a fluorine atom. In addition, when this filter is a structure containing a transparent substrate, substitution to the fluorine atom of a hydrogen atom is carried out to such an extent that the adhesiveness of the absorption layer containing pigment (I-12) and a transparent substrate does not fall.

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

  More specific examples of the compound (I-12) include the compounds shown in Table 4 below.

  As a compound (II), the compound shown by either of Formula (II-1)-(II-3) is mentioned, for example.

However, in Formula (II-1) and Formula (II-2), R ¹ and R ² each independently represent a hydrogen atom, a halogen atom, or an alkyl having 1 to 15 carbon atoms which may have a substituent. 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 formula (II-3), R ¹ , R ⁴ and R ^{9 to} R ¹² each independently represent a hydrogen atom, a halogen atom, or an alkyl having 1 to 15 carbon atoms which may have a substituent. And 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 the compound (II-1) and the compound (II-2) are independently an alkyl group having 1 to 15 carbon atoms from the viewpoint of solubility in transparent resin, visible light transmission, etc. Preferably, an alkyl group having 7 to 15 carbon atoms is more preferable, and at least one of R ¹ and R ² is further preferably an alkyl group having a branched chain having 7 to 15 carbon atoms, and both R ¹ and R ² have carbon atoms Particularly preferred are alkyl groups having 8 to 15 branched chains.

R ³ is independently preferably a hydrogen atom, a halogen atom, or an alkyl group having 1 to 3 carbon atoms, from the viewpoints of solubility in transparent resin, visible light transmittance, etc., and a hydrogen atom, a halogen atom, a methyl group More preferable. R ⁴ is preferably a hydrogen atom or a halogen atom, particularly preferably a hydrogen atom, from the viewpoint of the steepness of change near the boundary between the visible region and the near infrared region. R ⁵ in compound (II-1) and R ⁶ in compound (II-2) are preferably independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms which may be substituted with a halogen atom And a hydrogen atom, a halogen atom and a methyl group are more preferable.

More specific examples of compound (II-1) and compound (II-2) include the compounds shown in Tables 5 and 6 below. In Tables 5 and _{6, -C 8 H 17, -C} 4 H 9, -C 6 H 13 represents octyl group linear, butyl group, hexyl group, respectively.

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

R ⁴ is preferably a hydrogen atom or a halogen atom, particularly preferably a hydrogen atom, from the viewpoint of visible light transparency and easiness of synthesis. Each of R ⁷ and R ⁸ independently is preferably a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms which may be substituted with a halogen atom, and more preferably a hydrogen atom, a halogen atom, or a methyl group.

Each of R ^{9 to} R ¹² is preferably a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms which may be substituted with a halogen atom. As -CR < ⁹ > R < ¹⁰ > -CR < ¹¹ > R < ¹² >-, the divalent organic group shown by said group (11-1)-(11-3) or following formula (11-5) is mentioned.
—C (CH ₃ ) (CH ₂ —CH (CH ₃ ) ₂ ) —CH (CH ₃ ) — (11-5)

  More specific examples of the compound (II-3) include the compounds shown in Table 7 below.

  As a compound (III), the compound shown by either Formula (III-1) or Formula (III-2) is mentioned, for example.

However, in (III-1) and (III-2), each of R ^{52 to} R ⁶² independently represents 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 represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom Preferably, a hydrogen atom, a halogen atom, and a methyl group are more preferable. R ⁵⁸ is preferably a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, and from the viewpoint of synthesis ease, an alkyl group having 1 to 3 carbon atoms is more preferable. R ⁵⁶ , R ⁵⁷ and R ^{59 to} R ⁶² each independently preferably represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a substituent, and from the viewpoint of synthesis ease, A hydrogen atom is more preferred. More specific examples of the compound (III-1) and the compound (III-2) include the compounds shown in Table 8 and Table 9 below.

  Dye (A) may consist of 1 type of compounds, and may consist of 2 or more types of compounds. When it consists of 2 or more types of compounds, each compound does not necessarily have the property of a pigment | dye (A), and should just have the property of a pigment | dye (A) as a mixture.

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

  The dye (A) can be appropriately selected depending on the design of the present filter. The dye (A) may be, for example, a mixture of a dye (A1) and a dye (A2) having the following characteristics, and may be composed of only the dye (A1).

(A-1) The dye (A1) is at least one selected from the compounds (I) to (III), and is the maximum in the spectral transmittance curve of the wavelength of 400 to 1100 nm measured by being contained in a transparent resin. The absorption wavelength λ _{max (A1)} is in the wavelength range of 680 to 730 nm, and when the transmittance of the maximum absorption wavelength λ _{max (A1)} is adjusted to 10%, the wavelength is shorter than the maximum absorption wavelength λ _{max (A1)} The difference between the wavelength (hereinafter referred to as ".lambda. _{SH80 (A1)} " ₎ at which the light transmittance of the light shows 80% and the maximum absorption wavelength .lambda. _{Max (A1)} is 100 nm or less.

(A-2) The dye (A2) is at least one selected from the compounds (I) to (III), and is the maximum in a spectral transmittance curve of a wavelength of 400 to 1100 nm measured by being contained in a transparent resin. The absorption wavelength λ _{max (A2)} is in the wavelength range of 720 to 770 nm.

(A-3) the maximum absorption wavelength lambda _{max (A2)} minus the maximum absorption wavelength lambda _{max (A1)} from is 30nm or more 85nm or less.

  Examples of the dye (A1) include the compound (I), the compound (II-1) and the compound (II-2) among the compounds (I) to (III), and the compound (I-11-7) and the compound (I-12-15), the compound (I-12-23), the compound (I-12-24), the compound (II-1-7) and the like are preferable. Examples of the dye (A2) include the compound (II-3), the compound (III-1) and the compound (III-2) among the compounds (I) to (III).

  When the dye (A) is used together with the dye (X), a compound in which the obtained absorption layer satisfies the requirements of (ii-1) to (ii-3) described later is preferable.

  Specific examples of UV dyes include oxazoles, merocyanines, cyanines, naphthalimides, oxadiazoles, oxazines, oxazines, naphthalic acids, styryls, anthracenes, cyclic carbonyls, and triazoles. The pigment is mentioned. Among these, oxazole dyes and merocyanine dyes are preferable. Moreover, a UV dye may be used individually by 1 type in an absorption layer, and may use 2 or more types together.

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

  As transparent resin, acrylic resin, epoxy resin, ene-thiol resin, polycarbonate resin, polyether resin, polyarylate resin, polysulfone resin, polyether sulfone resin, polyparaphenylene resin, polyarylene ether phosphine oxide resin, polyamide resin And polyimide resins, polyamide imide resins, polyolefin resins, cyclic olefin resins, polyurethane resins, polystyrene resins and polyester resins (eg, polyethylene terephthalate resin, polyethylene naphthalate resin) and the like. One of these resins may be used alone, or two or more thereof may be mixed and used.

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

  The absorption layer further contains, within a range not impairing the effects of the present invention, an adhesion imparting agent, a color tone correction pigment, a leveling agent, an antistatic agent, a heat stabilizer, a light stabilizer, an antioxidant, a dispersant, a flame retardant, It may have optional components such as a lubricant and a plasticizer.

This filter satisfies (i-1) and (i-2) when the absorption layer contains the dye (X) such that the light transmittance at λ _{max -RE (X)} is 10%. Is more preferable, and it is more preferable to satisfy (i-3).
(I-1) The average transmittance in a wavelength range of 550 to 650 nm at an incident angle of 0 degree is 80% or more.
(I-2) The transmission area in the wavelength range of 810 to 870 nm at an incident angle of 50 degrees is 10% nm or less.
(I-3) The transmittance of 846 nm is 1% or less at an incident angle of 50 degrees.

  85% or more is preferable and, as for the average transmittance | permeability in (i-1), 90% or more is more preferable. 9.5% nm or less is preferable and, as for the transmission area in (i-2), 9.0% nm or less is more preferable. 0.9% or less is preferable and, as for the transmittance | permeability in (i-3), 0.8% or less is more preferable.

The optical properties of (i-1) contain other dyes, such as the dyes (A) shown below, in addition to the dye (X) as compared to the case where the absorbing layer contains only the dye (X) By doing this, it is assumed that the average transmittance is reduced. The condition of (i-1) is a condition which is preferably satisfied even when the absorbing layer contains a dye (X) and another dye. Here, in the present filter using an absorption layer containing only the dye (X) such that the transmittance at λ _{max -RE (X)} is 10%, in the wavelength range of 550 to 650 nm at an incident angle of 0 °. The average transmittance of light is preferably 90% or more.

  Moreover, regarding the optical property of (i-2) and (i-3), it is the characteristic by the pigment (X) which is hardly influenced by other pigments.

When the absorption layer contains the dye (A) in addition to the dye (X), when the dye (X) is contained so as to have a transmittance of 10% at λ _{max -RE (X)} , the wavelength is 400 to 1100 nm In the spectral transmittance curve of (ii), it is preferable to satisfy (ii-1) to (ii-3).
(Ii-1) The average transmittance of light in the wavelength range of 550 to 650 nm is 85% or more, preferably 90% or more.
(Ii-2) The average transmittance of light in the wavelength range of 680 to 720 nm is 20% or less.
(Ii-3) The average transmittance of light in the wavelength region of 810 to 870 nm is 25% or less.

  The content of the dye (X) in the absorption layer is preferably such that the filter satisfies (i-1) and (i-2) according to the design of the filter, and more preferably (i) It may be suitably selected so as to satisfy -3). In the absorbing layer, the content of the dye (X) blocks near-infrared light while securing the transmittance of visible light, and suppresses the incident angle dependency of the reflecting layer to light incident at a high angle, in particular From the viewpoint of reducing light leakage in the wavelength range of 800 to 900 nm at high incidence angles, 0.01 to 20 parts by mass is preferable with respect to 100 parts by mass of the transparent resin, and 0.03 to 10 parts by mass from the viewpoint of solubility Is more preferred.

  When the absorbing layer contains the dye (X) and the dye (A), the contents thereof are, for example, (i-1) and (ii-1) to (ii-3), respectively, according to the design of the present filter. It is suitably selected so as to satisfy the characteristics of.

  In this case, the content of the dye (X) in the absorption layer is the same as described above, and the content of the dye (A) is from the viewpoint of exhibiting the characteristics of the dye (A) while securing the transmittance of visible light. 0.01-20 mass parts is preferable with respect to 100 mass parts of transparent resin, and 0.03-15 mass parts is more preferable. Furthermore, 0.03-20 mass parts is preferable with respect to 100 mass parts of transparent resin, and, as for total content of pigment (X) and pigment (A), 0.03-15 mass parts is more preferable.

  In the present 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, desired optical properties may not be sufficiently exhibited. If the thickness is more than 100 μm, the flatness of the layer may be reduced, and the in-plane variation of the absorptivity may occur. The thickness of the absorbing layer is more preferably 0.3 to 50 μm. In addition, in the case of providing another functional layer such as a reflective layer or an anti-reflection layer, if the absorption layer is too thick, cracking or the like may occur depending on the material. Therefore, as for the thickness of an absorption layer, 0.3-10 micrometers is more preferable.

  The absorption layer is prepared, for example, by dissolving a dye (X), preferably a dye (X) and a dye (A), a transparent resin or a raw material component of a transparent resin, and each component to be blended as necessary in a solvent Alternatively, they may be dispersed to prepare a coating liquid, which may be applied to a substrate and dried, and may be cured if necessary. The substrate may be a transparent substrate included in the present filter, or may be a peelable substrate used only when forming the absorbing layer. Also, the solvent may be a dispersion medium which can be dispersed stably or a solvent which can dissolve it.

  In addition, the coating liquid may contain a surfactant for the purpose of improvement such as void due to fine bubbles, dent due to adhesion of foreign matter and the like, and repelling during the drying step. Furthermore, for example, a dip coating method, a cast coating method, or a spin coating method can be used to apply the coating liquid. The coating layer is coated on a substrate and dried to form an absorbent layer. When the coating liquid contains a raw material component of a transparent resin, curing treatment such as heat curing and light curing is further performed.

  In addition, the absorbent layer can also be produced 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, when the present filter includes a transparent substrate, this film may be stuck on the transparent substrate.

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

(Transparent substrate)
When a transparent substrate is used as the filter, the transparent substrate is not particularly limited as long as it transmits visible light of approximately 400 to 700 nm, and may be a material that absorbs near infrared light or near ultraviolet light. For example, inorganic materials such as glass and crystals, and organic materials such as transparent resin may be mentioned.

As glass which can be used for the transparent substrate, absorption type glass (near infrared ray absorption glass) containing copper ions in fluorophosphate glass, phosphate glass, etc., soda lime glass, borosilicate glass, alkali-free glass, quartz Glass etc. are mentioned. Note that "phosphate type glass", a part of the skeleton of glass also contains silicophosphate glasses composed of SiO _2.

  As the glass, an alkali metal ion (eg, Li ion, Na ion) having a small ion radius existing on the main surface of the glass plate by ion exchange at a temperature not higher than the glass transition point For example, chemically strengthened glass obtained by exchanging Na ions or K ions for Li ions and K ions for Na ions may be used.

  Examples of transparent resin materials 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 copolymer, and acrylic resins such as norbornene resin, polyacrylate and polymethyl methacrylate. And urethane resins, vinyl chloride resins, fluorine resins, polycarbonate resins, polyvinyl butyral resins, polyvinyl alcohol resins, polyimide resins and the like.

  Moreover, as crystal materials that can be used for the transparent substrate, birefringent crystals such as quartz, lithium niobate, sapphire and the like can be mentioned. The optical properties of the transparent substrate may have the above-described optical properties as an optical filter obtained by laminating the light absorbing layer, the reflective layer, and the like. Sapphire is preferred as the crystal material.

  The transparent substrate is preferably an inorganic material, particularly preferably glass or sapphire, from the viewpoints of shape stability relating to long-term reliability such as optical characteristics as an optical filter, mechanical characteristics and the like, and handling characteristics at the time of filter manufacture.

  The shape of the transparent substrate is not particularly limited, and may be block-like, plate-like, or film-like, 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 preferred. From the viewpoint of processability, a transparent substrate made of glass and having a 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. As a reflection layer, what has wavelength selectivity which permeate | transmits visible light and mainly reflects the light of wavelengths other than the light shielding area of an absorption layer is mentioned, for example. The reflective layer preferably has a reflective area that reflects near infrared light. In this case, the reflection area of the reflection layer may include a light shielding area in the near infrared area of the absorption layer. The reflective layer is not limited to the above-described characteristics, and may be appropriately designed to a specification that further blocks light of a predetermined wavelength range, for example, a near ultraviolet range.

  When the reflective layer has a reflective region that reflects near infrared light, it is preferable that the absorbing layer and the reflective layer have the following relationship.

In the absorption layer, the wavelength λ _AB-SHT 20 on the short wavelength side of the wavelength at which the transmittance is 20% in the absorption region at an incident angle of 0 ° is in the wavelength region of ₆₃₀ to 690 nm. It is preferable that the wavelength λ _RE-SHT 20 on the short wavelength side in which the transmittance is 20% in the region satisfy (iv-1).
(Iv-1) λ _{AB-SHT 20} + 30 nm λ λ _{RE-SHT 20} λ λ _{AB-SHT 20} + 70 nm

The reflective layer preferably further satisfies (iv-2).
(Iv-2) The average transmittance _| permeability in the light of the wavelength range from (lambda) _RE-SHT20 to (lambda) _RE-SHT20 + 300 nm is 10% or less.

  In the filter, the absorption layer contains the dye (X) to suppress the incident angle dependency of the reflective layer to light incident at a high angle by the reflective layer, in particular, 800 to 900 nm at a high incident angle Light leakage in the wavelength range can be reduced.

The reflective layer is formed 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 stacked. 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 . Among these, TiO ₂ is preferable from the viewpoint of film formability, 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, etc. in film formability.

  Furthermore, in the reflective layer, the transmittance preferably changes sharply in the boundary wavelength region between the transmission region and the light shielding region. For this purpose, the total number of laminated dielectric multi-layer films constituting the reflective layer is preferably 15 or more, more preferably 25 or more, and still more preferably 30 or more. However, if the total number of laminations increases, warpage or the like occurs or the film thickness increases, the total number of laminations is preferably 100 layers or less, more preferably 75 layers or less, and still more preferably 60 layers or less. Moreover, as for the film thickness of a dielectric multilayer, 2-10 micrometers is preferable.

  If the total number of laminated layers of the dielectric multilayer film and the film thickness are in the above range, the reflective layer satisfies the requirements for miniaturization, and as the incident angle dependency, the range of the above (1) is satisfied while maintaining high productivity. it can. Further, for the formation of the dielectric multilayer film, for example, a vacuum film forming process such as a CVD method, a sputtering method, or a vacuum evaporation method, or a wet film forming process such as a spray method or a dip method can be used.

  In the reflective layer, one layer (one group of dielectric multilayer films) may provide predetermined optical characteristics, or two layers may provide predetermined optical characteristics. When it has two or more layers, each reflecting layer may have the same configuration or different configurations. When two or more reflective layers are provided, the reflective layer is usually composed of a plurality of reflective layers having different reflection bands.

  As an example, in the case of providing two reflective layers, one is a near infrared reflective layer that blocks light in a short wavelength band in the near infrared region, and the other is a long wavelength band in the near infrared region and a near ultraviolet region. It is good also as a near-infrared and near-ultraviolet reflecting layer which shields the light of both areas. Also, for example, when the filter has a transparent substrate, when providing two or more reflective layers, all may be provided on one main surface of the transparent substrate, and each reflective layer is a transparent substrate. You may provide on both the main surfaces on both sides.

(Antireflection layer)
Examples of the antireflective layer include a dielectric multilayer film, an intermediate refractive index medium, and a moth-eye structure in which the refractive index gradually changes. Among them, dielectric multilayer films are preferable from the viewpoint of optical efficiency and productivity. The antireflective layer is obtained by alternately laminating dielectric films in the same manner as the reflective layer.

  The present filter may include, as another component, for example, a component (layer) that provides absorption by inorganic fine particles or the like that controls 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 boride and the like. ITO fine particles and cesium tungstate fine particles have high visible light transmittance and have light absorbability in a wide range of infrared wavelength region exceeding 1200 nm, so they can be used when such infrared light shielding properties are required. .

  This filter has a reflection layer and an absorption layer containing a dye (X) to suppress the incidence angle dependency to light incident at a high angle, in particular, a wavelength of 800 to 900 nm at a high incidence angle While being able to reduce the light leak of the area | region, the transmittance | permeability of visible light is high, and it is excellent also in light resistance.

This filter satisfies the above (i-1) and (i-2) when the absorbing layer contains the dye (X) such that the transmittance at λ _{max -RE (X)} is 10%. Is more preferable, and it is more preferable to satisfy the above (i-3).

This filter preferably satisfies the following optical properties (i-4) and (i-5) when the absorption layer further contains a dye (A).
(I-4) The average of the difference in the transmittance of light with an incident angle of 0 degrees and an incident angle of 30 degrees in the wavelength range of 703 to 739 nm is 10% / nm or less.
(I-5) The maximum transmittance of light in a wavelength range of 713 to 763 nm at an incident angle of 0 degree is 20% or less.

  8% / nm or less is more preferable, and, as for the average of the difference of the transmittance | permeability in said (i-4), 5% / nm or less is more preferable. In addition, with the average of the difference in transmittance in (i-4), the difference between the transmittance at an incident angle of 0 degrees and the transmittance at an incident angle of 30 degrees is taken every 1 nm in the wavelength range of 703 to 739 nm. It corresponds to the result of dividing the total transmission [%] of the difference by the number of sampled wavelengths (= 37 points). 15% or less is more preferable, and, as for the largest transmittance | permeability in (i-5), 12% or less is further more preferable.

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

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

<Synthesis and preparation of pigment>
Compounds (X-11-1), (X-11-4) and (X-11-3) were used as dye (A) as dye (A) as dye (X) used in the examples. 12-24) were synthesized by a conventional method.

  In addition, squalilium dyes (SQ-1) represented by the following formula (SQ-1) not satisfying the characteristics of the dye (X) used in the comparative example, and those represented by the following formulas (CY-1) and (CY-2), respectively Cyan dyes (CY-1) and Cyan dyes (CY-2) were synthesized by a conventional method. Furthermore, three types of commercially available phthalocyanine dyes, FDN-015, FDN-002, and FDN-003 (all trade names of Yamada Chemical Co., Ltd.) were prepared. In addition, for the evaluation of the optical characteristics of these dyes, using an ultraviolet-visible spectrophotometer (U-4100, manufactured by Hitachi High-Technologies Corporation), the following optical characteristics (spectral transmittance curve) are also evaluated. Similarly, U-4100 was used.

(1) Production of Dye (X-11-1) A dye (X-11-1) was synthesized according to the reaction route shown below. In the following reaction route formulas, "t-But" represents a tertiary butyl group, and "n-But" represents an n-butyl group. The same applies to other formulas.

<Step 1>
N, N-diethyl-3-aminophenol (5 g, 30.3 mmol) and methyl 4,4-dimethyl-3-oxovalerate (6.1 g, 60.6 mmol) were added to a 200 ml eggplant flask and nitrogen atmosphere was established 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 completion of the reaction, the reaction solution was cooled to room temperature, ethyl acetate and 0.5 M hydrochloric acid were added, and then extracted with hexane and ethyl acetate. After removing the solvent, a brown oil (4.6 g, 21.2 mmol, 70% yield) was isolated by flash column chromatography (hexane / ethyl acetate).

<Step 2>
The product obtained in Step 1 (4 g, 18.5 mmol) was placed in a 500 ml eggplant flask and dissolved in 40 ml of tetrahydrofuran. Under a nitrogen atmosphere, 10 ml of 1 M methylmagnesium bromide was dropped at 0 ° C., and the mixture was warmed to room temperature and stirred for 20 hours. After 10 ml of 1 M methylmagnesium bromide was dropped again at room temperature, the mixture was stirred for 12 hours, and another 10 ml of 1 M methylmagnesium bromide was further added and stirred for 1 hour. After completion of the reaction, the reaction solution was poured into 50 ml of ice water, 40 ml of 42% aqueous tetrafluoroboric acid 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 and the solvent was removed. The resulting solid was washed with hexane to give an amber solid (4.6 g, 15.2 mmol, 83%).

<Step 3>
The product (4.6 g, 12.8 mmol) obtained in Step 2 is placed in a flask, dissolved in 70 ml of 1-butanol, and triethylamine-dicyanoalkene squara synthesized with reference to US Patent Application Publication No. 2005/0202565. Phosphate (2.1 g, 6.5 mmol) and quinoline (1.7 g, 13.0 mmol) were added and stirred for 2 hours under reflux conditions. After filtering the reaction solution, the obtained brown solid was purified by flash column chromatography (methanol / dichloromethane) to isolate the desired brown solid (1.8 g, 3.2 mmol, 49% yield).

  The obtained brown solid was identified by 1 H NMR to confirm that it was a compound (X-11-1).

(2) Production of dye (X-11-4) A method of producing dye (X-11-1) except that N, N-dibutyl-3-aminophenol (10 g, 45.1 mmol) was used as a raw material and In a similar manner, dye (X-11-4) was obtained as a brown solid (2.5 g, 3.75 mmol) in a total yield of 52%. Identification of the obtained brown solid, compound (X-11-4) was performed by 1H NMR.

(3) Preparation of Dye (X-11-3) A dye (X-11-3) was synthesized according to the reaction route shown below.

<Step 1>
Diphosphorus pentoxide (30 g, 106 mmol) is dissolved in 300 g of methanesulfonic acid and methyl 4,4-dimethyl-3-oxovalerate (25.2 g, 249 mmol) and resorcinol (16.5 g, 150 mmol) are added at room temperature. The mixture was heated and stirred for 22 hours. After addition of 1 L of water at 0 ° C., the solid obtained is filtered. Recrystallization with methanol / water = 9/1 gave the desired yellow solid (10.1 g, 46.4 mmol, 31% yield).

<Step 2>
In a flask, put the product obtained in Step 1 (2 g, 9.2 mmol), potassium carbonate (1.5 g, 11.0 mmol), a trace amount of potassium iodide, dissolve in 10 ml of isopropanol and 20 ml of methyl ethyl ketone, and react The solution was stirred at reflux for 14 hours. Water was added and the mixture was cooled to room temperature, extracted with ethyl acetate, dried over magnesium sulfate and the solvent was removed. The obtained solid was recrystallized with methanol to give a white solid (1.3 g, 4.2 mmol, 46%).

<Step 3>
The product obtained in Step 1 (1.3 g, 4.2 mmol) was placed in a flask and dissolved in 10 ml of tetrahydrofuran. Under a nitrogen atmosphere, 10 ml of 1 M methylmagnesium bromide was added dropwise at 0 ° C., and the mixture was warmed to room temperature and stirred for 12 hours. Again 10 ml of 1 M methylmagnesium bromide was added dropwise at room temperature and stirred for 5 hours. After completion of the reaction, the reaction solution was poured into 100 ml of ice water, and 75 ml of 42% aqueous tetrafluoroboric acid solution was added, followed by stirring at room temperature for 1 hour. Extraction with dichloromethane followed by drying over anhydrous magnesium sulfate and removal of the solvent gave a brown oil quantitatively (1.6 g, 4.2 mmol).

<Step 4>
The product obtained in Step 3 (1.6 g, 4.2 mmol) is dissolved in a flask and dissolved in 20 ml of 1-butanol, and the triethylamine-dicyano alkene squarate (0.64 g synthesized with reference to US Pat. No. 20050202565) , 2.0 mmol) and quinoline (0.6 g, 4.7 mmol), and then stirred for 2 hours under reflux conditions. The reaction solution was filtered and then reprecipitated with dichloromethane and hexane. The resulting brown solid was purified by flash column chromatography (methanol / dichloromethane) to isolate the desired brown solid (0.67 g, 1.1 mmol, 55% yield).

  The obtained brown solid was identified by 1 H NMR to confirm that it was a compound (X-11-3).

<Optical characteristics>
The optical properties of the dye (X) and the dye (D) were evaluated as follows. The results are shown in Table 10.
(In dichloromethane)
(1) Molar extinction coefficient [L / (mol · cm)]
The molar absorption coefficient of the dye (X) and dye (D) prepared above in dichloromethane was measured.

(2) λ _{max-DCM (X), (D)} [nm]
Maximum absorption wavelength λ _max -DCM _(x) , maximum absorption wavelength λ _max -DCM in a spectral transmittance curve of wavelength 400 to 1100 nm measured with a solution of dye (D) dissolved in dye (D) _X) was measured.

(3) Average transmittance: 550-650 [%]
In a spectral transmittance curve at a wavelength of 400 to 1100 nm measured in a solution dissolved in dichloromethane so that the transmittance at λ _{max -DCM (X) and (D)} is 10%, in a wavelength range of 550 to 650 nm The average transmittance in light was determined.

(4) Average transmittance: 830-900 [%]
In the spectral transmittance curve of said (3), the average transmittance | permeability in the light of a wavelength region of 830-900 nm was calculated | required.

(In transparent resin)
(5) Mass extinction coefficient [/ (cm · mass%)]
Each of the pigment (X) and pigment (D) prepared above was sufficiently stirred in a polyimide resin C3G30 (trade name; manufactured by Mitsubishi Gas Chemical Co., Ltd.) and cyclohexanone, and was uniformly dissolved. The obtained solution was applied on a glass plate (D263; manufactured by SCHOTT) and dried to obtain an absorption layer with a film thickness of 1.0 μm. The mass extinction coefficient is the internal transmittance T [%] of light at the maximum absorption wavelength in the wavelength range of 350 to 1200 nm (= actual transmittance [%] / [100 [%]-actual reflectance [%]] x 100 [%]) Was calculated and calculated by −log ₁₀ (T / 100).

(6) λ _{max-RE (X), (D)} [nm]
It carried out similarly to said (5), and obtained the glass plate with an absorption layer with a film thickness of 1.0 micrometer. The spectral transmittance curve of the absorbing layer was obtained using the spectral transmittance curve of the glass plate with an absorbing layer at a wavelength of 400 to 1100 nm and the spectral transmittance curve of the glass plate. The maximum absorption wavelength λ _{max -RE (X)} and the maximum absorption wavelength λ _{max -RE (D)} in the spectral transmittance curve were measured.

(7) Average transmittance: 550-650 [%]
In the above (6), the addition amount of the dye (X) and the dye (D) is adjusted so that the light transmittance at λ _{max-RE (X) and (D)} becomes 10%, and the glass plate with the absorbing layer I got The spectral transmittance curve of the absorbing layer is obtained using the spectral transmittance curve of the glass plate with a wavelength of 400 to 1100 nm and the spectral transmittance curve of the glass plate, and the average transmittance of light in the wavelength range of 550 to 650 nm is obtained. I asked.

(8) Average transmittance: 830-900 [%]
In the spectral transmittance curve of (7) above, the average transmittance of light in the wavelength region of 830 to 900 nm was determined.

-Dye remaining rate (light resistance)
In the same manner as in (7) above, a glass plate with an absorption layer is obtained, and further, an antireflection layer consisting of a dielectric multilayer film is formed on the absorption layer of the glass plate with an absorption layer by a vapor deposition machine. did.

The light resistance test of the obtained sample was conducted using a weather meter tester (manufactured by Suga Test Instruments Co., Ltd.) using a xenon lamp as a light source. The residual rate of the dye at the maximum absorption wavelength was evaluated after irradiation of 6000 J / m ² with an integrated light amount at a wavelength of 300 to 400 nm. The residual rate was calculated as a percentage of mass extinction coefficient after irradiation to mass extinction coefficient before irradiation. Those with a residual rate of 90% or more were regarded as “o”, and 80% or more and less than 90% as “Δ”.

(Absorptive layer (including dye (A)))
For each of the dye (X) and the dye (D) prepared above, the addition amount is adjusted so that the light transmittance at λ _{max -RE (x) and (D)} is 10%, The compound (I-12-24) was added as a dye (A), sufficiently stirred in a polyimide resin C3G30 (trade name; manufactured by Mitsubishi Gas Chemical Co., Ltd.) and cyclohexanone, and uniformly dissolved. The obtained solution was applied on a glass plate (D263; manufactured by SCHOTT) and dried to obtain an absorption layer with a film thickness of 1.0 μm. Table 10 shows the content (parts by mass) of the dye (X) or the dye (D) and the dye (A) with respect to 100 parts by mass of the polyimide resin.

  The spectral transmittance curve of the absorbing layer is obtained using the spectral transmittance curve of the glass plate with an absorbing layer at a wavelength of 400 to 1100 nm and the spectral transmittance curve of the glass plate, and (ii-1) light in the wavelength region of 550 to 650 nm The average transmittance of (ii-2), the average transmittance of light in the wavelength region of 680 to 720 nm, and the average transmittance of light in the wavelength region of (ii-3) 810 to 870 nm were determined.

[Examples 1 to 7]
The absorption layer shown in Table 11 was produced on one main surface of a glass plate (D263; SCHOTT made, thickness: 0.21 mm). As a transparent resin, polyimide resin C3G30 (trade name; manufactured by Mitsubishi Gas Chemical Co., Ltd.) was used, and the film thickness of the absorption layer was 1 μm. The content of the pigment in Table 11 is a part by mass with respect to 100 parts by mass of the transparent resin, and for each of the pigment (X) and the pigment (D), the addition amount is λ _{max-RE (x), (D)} It is an amount adjusted so that the light transmittance is 10%. A reflective layer having a near-infrared reflective region made of a dielectric multilayer film was designed on the other main surface of the glass plate with an absorption layer thus obtained, to form an optical filter. Example 1 is an example, and examples 2 to 7 are comparative examples.

  The optical characteristics of the reflective layer used are the transmission area of the light in the wavelength range of 810 to 870 nm at an incident angle of 50 degrees and the average transmittance of light in the wavelength range of 550 to 650 nm at an incident angle of 0 degrees. Of the light in the wavelength region of 846 nm at an incident angle of 50 degrees was 6.4 [%].

  About the obtained optical filter, the spectral transmission factor curve of wavelength 400-1100 nm was measured in the incident angle 0 degree and the incident angle 50 degree, and the following optical characteristics were evaluated. The results are shown in Table 11.

(I-1) Average transmittance in the wavelength range of light of 550 to 650 nm at an incident angle of 0 degree.
(I-2) Transmission area in the wavelength region of light of 810 to 870 nm at an incident angle of 50 degrees.
(I-3) Transmittance of light in the wavelength region of 846 nm at an incident angle of 50 degrees.

  As can be seen from Table 11, Example 1, which is an example of the present filter, is excellent in the light blocking property of near infrared light and can suppress the incident angle dependency to light incident at a high angle, particularly at a high incident angle. The light leakage in the wavelength range of 800 to 900 nm can be reduced, the transmittance of visible light is high, and as shown in Table 10, the light resistance is also excellent. As shown in Table 10, the optical filters of Comparative Examples 6 and 7 do not have sufficient light resistance of the absorbing layer.

[Examples 8-14]
Examples 8 to 14 are the same as Examples 1 to 7 except that the absorbing layer further contains 3.9 parts by mass of a compound (I-12-24) as a dye (A) based on 100 parts by mass of the polyimide resin. The optical filter of Example 8 is an example, and examples 9 to 14 are comparative examples.

  About the obtained optical filter, the spectral transmittance curve of wavelength 400-1100 nm is measured at an incident angle of 0 degrees, an incident angle of 30 degrees, and an incident angle of 50 degrees, and the above (i-1) to (i-3) and the following The optical properties of were evaluated. The results are shown in Table 12.

(I-4) The average of the difference in the transmittance of light with an incident angle of 0 degrees and an incident angle of 30 degrees in the wavelength range of 703 to 739 nm.
(I-5) Maximum transmittance of light in a wavelength range of 713 to 763 nm at an incident angle of 0 degree.

  As can be seen from Table 12, Example 8 which is an example of the present filter containing the dye (A) in addition to the dye (X) is excellent in the light blocking property of near infrared light and is incident on light incident at a high angle. Angle dependence can be suppressed, and in particular, light leakage in the wavelength range of 800 to 900 nm at high incident angles can be reduced, and the visible light transmittance is high, and the spectral curve is the boundary region between near infrared light and visible light The slope is steep and the light resistance is excellent.

  The optical filter of the present invention is excellent in the light shielding property of near infrared light and can suppress the incident angle dependency to light incident at a high angle, and in particular, light leakage in the wavelength range of 800 to 900 nm at a high incident angle. Since it can be reduced, the transmittance of visible light is high, and the light resistance is excellent, it is useful for applications such as an imaging device such as a digital still camera whose performance has been advanced in recent years.

  DESCRIPTION OF SYMBOLS 10A, 10B ... Optical filter, 11 ... Absorption layer, 12 ... Reflection layer, 13 ... Transparent substrate, 14 ... Antireflection layer.

Claims (14)

An optical filter comprising: an absorption layer containing a squarylium dye (X) having the following characteristics (1) to (4) and a transparent resin; and a reflection layer formed of a dielectric multilayer film.
(1) When it is made to melt | dissolve in a dichloromethane, the molar absorption coefficient in the light of wavelength 350-1200 nm is 150000 [L / (mol * cm)] or more.
(2) In a spectral transmittance curve at a wavelength of 400 to 1100 nm measured with a solution dissolved in dichloromethane, the maximum absorption wavelength λ _max -DCM _(X) is in a wavelength range of 800 to 870 nm.
(3) A wavelength of 550 to 650 nm in a spectral transmittance curve of a wavelength of 400 to 1100 nm, which is measured with a solution dissolved in dichloromethane so that the transmittance at 10 nm is the maximum absorption wavelength λ _max -DCM _(X) The average transmittance in the region is 90% or more.
(4) A wavelength of 830 to 900 nm in a spectral transmittance curve of a wavelength of 400 to 1,100 nm, which is measured in a solution dissolved in dichloromethane so that the transmittance at the maximum absorption wavelength λ _max -DCM _(X) is 10% The average transmittance in the region is 65% or less. The optical filter according to claim 1, wherein the squarylium dye (X) satisfies the following (5) to (8).
(5) The mass absorption coefficient in light with a wavelength of 350 to 1200 nm when it is contained in the transparent resin is 2000 / (cm · mass%) or more.
(6) In the spectral transmittance curve of the wavelength of 400 to 1100 nm measured by incorporating in the transparent resin, the maximum absorption wavelength λ _{max -RE (X)} is in the wavelength range of 800 to 870 nm.
(7) A spectral transmittance curve of a wavelength of 400 to 1100 nm, which is measured to be contained in the transparent resin so that the transmittance at the maximum absorption wavelength λ _{max-RE (X)} is 10%, a wavelength of 550 to 650 nm The average transmittance in the region is 90% or more.
(8) In the spectral transmittance curve of wavelength 400 to 1100 nm, which is measured to be contained in the transparent resin so that the transmittance at the maximum absorption wavelength λ _{max-RE (X)} is 10%, the wavelength of 830 to 900 nm The average transmittance in the region is 65% or less. The optical filter according to claim 1, wherein the squarylium dye (X) is a compound represented by the following formula (X-1).

However, in the formula (X-1), each of A is a group which may have a substituent and which has a monocyclic to tricyclic aromatic ring of 5 to 6 members as a skeleton. The aromatic ring may contain one or more hetero atoms selected from N, S, O and Se, n is independently 0 or 1, and R ¹⁰¹ is independently substituted. It is also a good hydrogen atom. The optical filter according to claim 3, wherein the formula (X-1) is the following formula (X-11).

However, the symbols in formula (X-11) are as follows.
R ¹⁰¹ each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms which may have a substituent,
R ¹⁰² , R ¹⁰³ and R ^{105 to} R ¹⁰⁷ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms which may have a substituent, a sulfo group, a hydroxyl group, a cyano Group, a nitro group, a carboxy group, a phosphoric acid group, -NR ¹⁰⁸ R ¹⁰⁹ (R ¹⁰⁸ and R ¹⁰⁹ each independently represent a hydrogen atom or an alkyl group which may have a substituent having 1 to 15 carbon atoms Yes,)
R ¹⁰⁴ each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms or an alkoxy group, an acyloxy group having 1 to 10 carbon atoms, -NR ¹⁰⁸ R ¹⁰⁹ (R ¹⁰⁸ and R ¹⁰⁹ are And each independently represents a hydrogen atom or an alkyl group having 1 to 15 carbon atoms and may have a substituent. The compound according to claim 4, wherein in the formula (X-11), R ¹⁰⁴ is --NR ¹⁰⁸ R ¹⁰⁹ (R ¹⁰⁸ and R ¹⁰⁹ each independently represent an alkyl group having 1 to 15 carbon atoms). Optical filter. The absorption layer further comprises a dye (A) having a maximum absorption wavelength λ _max -DCM _(A) at 600 to 750 nm in a spectral transmittance curve at a wavelength of 400 to 1100 nm measured with a solution dissolved in dichloromethane. The optical filter according to any one of Items 1 to 5. When the absorption layer contains the squarylium dye (X) such that the transmittance at the maximum absorption wavelength λ _{max-RE (X)} is 10%, the absorption layer has a spectral transmittance curve at a wavelength of 400 to 1100 nm. The optical filter according to claim 6, wherein the following (ii-1) to (ii-3) are satisfied.
(Ii-1) The average transmittance in a wavelength range of 550 to 650 nm is 85% or more.
(Ii-2) The average transmittance in the wavelength range of 680 to 720 nm is 20% or less.
(Ii-3) The average transmittance in the wavelength region of 810 to 870 nm is 25% or less. When the absorption layer contains the squarylium dye (X) such that the transmittance at the maximum absorption wavelength λ _{max-RE (X)} is 10%, the following (i-1) and (i-2) are satisfied: The optical filter according to any one of claims 1 to 7.
(I-1) The average transmittance in a wavelength range of 550 to 650 nm at an incident angle of 0 degree is 80% or more.
(I-2) The transmission area in the wavelength range of 810 to 870 nm at an incident angle of 50 degrees is 10% nm or less. When the said absorption layer contains the said squalilium pigment | dye (X) so that the transmittance _| permeability in maximum absorption wavelength ₍ lambda) _{max-RE (X)} may be 10%, the following (i-3) is satisfy | filled. Optical filter.
(I-3) The transmittance in a wavelength region of 846 nm at an incident angle of 50 degrees is 1% or less.   The transparent resin includes polyester resin, acrylic resin, epoxy resin, ene / thiol resin, polycarbonate resin, polyether resin, polyarylate resin, polysulfone resin, polyether sulfone resin, polyparaphenylene resin, polyarylene ether phosphine oxide The optical filter according to any one of claims 1 to 9, comprising 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, and a polystyrene resin.   The optical filter according to any one of claims 1 to 10, wherein the transparent resin has a glass transition temperature of 140 ° C or higher.   The optical filter according to any one of claims 1 to 11, further comprising a transparent substrate, wherein the absorption layer and the reflection layer are respectively provided on the main surface of the transparent substrate.   The optical filter according to claim 12, wherein the transparent substrate is made of glass or sapphire.   An imaging device comprising a solid-state imaging device, an imaging lens, and the optical filter according to any one of claims 1 to 13.

Images