阅读说明：本技术 滤光片以及成像装置 (Optical filter and imaging device ) 是由 铃木翔子 盐野和彦 山田纱友梨 保高弘树 于 2019-01-30 设计创作，主要内容包括：本发明涉及一种滤光片,所述滤光片具有吸收层和反射层,所述吸收层含有近红外线吸收色素和透明树脂,其中,所述近红外线吸收色素在透明树脂中的最大吸收波长为760nm～900nm、并且435nm～480nm的平均透射率T<Sub>435-480平均TR</Sub>、480nm～590nm的平均透射率T<Sub>480-590平均TR</Sub>为90％以上,所述近红外线吸收色素在二氯甲烷中的最大吸收波长为760nm～900nm、并且435nm～480nm的平均透射率T<Sub>435-480平均DCM</Sub>为95％以上、480nm～590nm的平均透射率T<Sub>480-590平均DCM</Sub>为97％以上,T<Sub>435-480平均DCM</Sub>与T<Sub>435-480平均TR</Sub>之差和T<Sub>480-590平均DCM</Sub>与T<Sub>480-590平均TR</Sub>之差为10.5％以下,并且所述滤光片的入射角为60度、800nm～900nm的平均透射率为5％以下。(The present invention relates to an optical filter having an absorption layer and a reflection layer, wherein the absorption layer contains a near-infrared absorbing dye and a transparent resin, and the near-infrared absorbing dye has a maximum absorption wavelength of 760nm to 900nm in the transparent resin and an average transmittance T of 435nm to 480nm 435- 480 to 590nm, average transmittance T 480-590 average TR 90% or more, and an average transmittance T of the near infrared ray absorbing dye in methylene chloride, wherein the absorption maximum wavelength of the near infrared ray absorbing dye in methylene chloride is 760 to 900nm and 435 to 480nm 435- An average transmittance T of 95% or more and 480 to 590nm 480-590 average DCM Is more than 97 percent, T 435- And T 435- Sum of difference T 480-590 average DCM And T 480-590 average TR The difference is 10.5% or less, and the average transmittance of the optical filter is 5% or less at an incident angle of 60 degrees and at 800nm to 900 nm.)

1. An optical filter comprising an absorbing layer and a reflecting layer, wherein the absorbing layer contains a near-infrared absorbing dye (A) and a transparent resin, and the near-infrared absorbing dye (A) satisfies the following (i-1) to (i-5):

(i-1) a maximum absorption wavelength λ in a spectral transmittance curve at a wavelength of 400nm to 1100nm measured by including the near infrared ray absorbing dye (A) in the transparent resin_{Maximum (A) TR}In the wavelength range of 760nm to 900nm,

(i-2) at a wavelength such that the absorption maximum is λ_{Maximum (A) TR}An average transmittance T of light in a wavelength range of 435 to 480nm in a spectral transmittance curve of 400 to 1100nm measured with the near infrared ray absorbing dye (A) contained in the transparent resin so that the transmittance of the near infrared ray absorbing dye (A) is 10%_435-And an average transmittance T of light in a wavelength range of 480nm to 590nm_480-The content of the active ingredients is more than 90 percent,

(i-3) maximum absorption wavelength λ in spectral transmittance curve of 400nm to 1100nm wavelength measured by dissolving the near infrared ray absorbing dye (A) in methylene chloride_{Maximum (A)DCM}In the wavelength range of 760nm to 900nm,

(i-4) at a wavelength such that the absorption maximum is λ_{Maximum (A) DCM}An average transmittance T of light in a wavelength range of 435 to 480nm in a spectral transmittance curve of 400 to 1100nm measured with the near infrared ray absorbing dye (A) contained in methylene chloride so that the transmittance of the dye (A) is 10%_435-95% or more and an average transmittance T of light in a wavelength range of 480 to 590nm_480-The content of the active carbon is more than 97 percent,

(i-5) average Transmission T_435-And average transmission T_435-Difference between the values and average transmittance T_480-And average transmission T_480-The difference is 10.5% or less, and

the filter satisfies the following (ii-1):

(ii-1) an average transmittance of light in a wavelength range of 800nm to 900nm at an incident angle of 60 degrees of 5% or less.

2. The optical filter according to claim 1, wherein a mass extinction coefficient when the near-infrared absorbing dye (a) is contained in the transparent resin is 1900/(cm · mass%) or more.

3. The filter according to claim 1 or 2, wherein the near-infrared absorbing pigment (a) comprises a cyanine-based pigment.

4. The optical filter according to any one of claims 1 to 3, wherein the near-infrared absorbing pigment (A) comprises a cyanine-based pigment represented by the following formula (A1) or the following formula (A2),

wherein the symbols in the formulae (A1) and (A2) are as follows,

R¹⁰¹～R¹⁰⁹and R¹²¹～R¹³¹Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 15 carbon atoms which may have a substituent, an alkoxy group having 1 to 15 carbon atoms which may have a substituent, or an aryl group having 5 to 20 carbon atoms which may have a substituent; r^110～114And R^132～136Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 15 carbon atoms or an alkoxy group having 1 to 15 carbon atoms,

plural R contained in each formula¹⁰¹～R¹⁰⁹And a plurality of R¹²¹～R¹³¹May be the same as each other, may be different from each other,

X^-represents a monovalent anion of a monovalent anion,

n1 and n2 are 0 or 1; bonded to a radical containing- (CH)₂)_n1A carbocyclic ring of and containing- (CH)₂)_n2The hydrogen atom on the carbon ring of (E) may be substituted with a halogen atom, an alkyl group having 1 to 15 carbon atoms which may have a substituent, or an aryl group having 5 to 20 carbon atoms which may have a substituent.

5. The optical filter according to any one of claims 1 to 4, wherein the transparent resin comprises at least one selected from a polyester resin, a polycarbonate resin, a polyimide resin, and an acrylic imide resin.

6. The optical filter according to any one of claims 1 to 5, wherein the absorption layer further comprises a near-infrared absorbing dye (D), and the absorption maximum wavelength λ is in a spectral transmittance curve of 400nm to 1100nm in wavelength measured by including the near-infrared absorbing dye (D) in the transparent resin_{Maximum (D) TR}In a wavelength range of 680nm to 750nm, and the filter satisfies the following (ii-2) to (ii-6):

(ii-2) an average transmittance of 70% or more of light in a wavelength range of 435nm to 480nm at an incident angle of 0 degree,

(ii-3) an average transmittance of light in a wavelength range of 490nm to 580nm at an incident angle of 0 ℃ of 84% or more,

(ii-4) an average transmittance of light in a wavelength range of 800nm to 900nm at an incident angle of 60 degrees of 1% or less,

(ii-5) a maximum transmittance of light in a wavelength range of 800nm to 900nm at an incident angle of 60 degrees of 10% or less,

(ii-6) wavelength λ on the short wavelength side of the wavelength showing 20% transmittance at an incident angle of 0 degree_SHT20-0°A wavelength λ on the short wavelength side of a wavelength in the wavelength range of 640nm to 690nm and exhibiting a transmittance of 20% at an incident angle of 30 DEG_SHT20-30°And wavelength lambda_SHT20-0°The difference is 10nm or less.

7. The filter according to claim 6, wherein the near-infrared absorbing dye (D) is a compound represented by any one of the following formulas (I) to (III),

wherein the symbols in formula (I) are as follows,

R²⁴and R²⁶Each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyloxy group having 1 to 10 carbon atoms, -NR²⁷R²⁸(R²⁷And R²⁸Each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, -C (═ O) -R²⁹(R²⁹A hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an aryl group having 6 to 11 carbon atoms which may have a substituent, or a linear or branched saturated or unsaturated hydrocarbon group or saturated cyclic hydrocarbon group which may have a saturated ring structure and which may be substituted with one or more aryl groups having 7 to 18 carbon atoms which may have a substituent and may have an oxygen atom between carbon atoms), -NHR³⁰or-SO₂-R³⁰(R³⁰A hydrocarbon group of 1 to 25 carbon atoms each of which has at least one hydrogen atom which may be substituted with a halogen atom, a hydroxyl group, a carboxyl group, a sulfo group or a cyano group and may have an unsaturated bond, an oxygen atom or a saturated or unsaturated ring structure between carbon atoms), or a group represented by the following formula (S)Group (R)⁴¹、R⁴²Independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms; k is 2 or 3),

R²¹and R²²、R²²And R²⁵And R²¹And R²³May be linked to each other and form, together with the nitrogen atom, a five-or six-membered heterocycle A, a heterocycle B and a heterocycle C, respectively;

for R in the case of the formation of a heterocycle A²¹And R²²As R²¹And R²²A divalent group-Q-bonded to the substrate, wherein the divalent group represents an alkylene group in which a hydrogen atom may be substituted with an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an acyloxy group having 1 to 10 carbon atoms which may have a substituent, or an alkyleneoxy group in which a hydrogen atom may be substituted with an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an acyloxy group having 1 to 10 carbon atoms which may have a substituent;

for R in the case of the formation of a heterocyclic ring B²²And R²⁵And R in the case of the formation of a heterocycle C²¹And R²³As R²²And R²⁵And R²¹And R²³Each bonded divalent radical-X¹-Y¹-and-X²-Y²- (one side bound to nitrogen being X)¹And X²)，X¹And X²Each is a group represented by the following formula (1x) or (2x), Y¹And Y²Each is a group represented by any one selected from the following formulae (1y) to (5 y); at X¹And X²Y is a group represented by the following formula (2x)¹And Y²Each may be a single bond, in which case there may be an oxygen atom between carbon atoms;

in the formula (1x), 4 Zs independently represent a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or-NR³⁸R³⁹(R³⁸And R³⁹Each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms); r³¹～R³⁶Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms, R³⁷Represents an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms;

R²⁷、R²⁸、R²⁹、R³¹～R³⁷r in the case where no heterocyclic ring is formed²¹～R²³And R²⁵May be bonded to any other one of them to form a five-membered ring or a six-membered ring; r³¹And R³⁶、R³¹And R³⁷Can be directly bonded;

r in the case where no heterocyclic ring is formed²¹And R²²Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, an allyl group which may have a substituent, an aryl group having 6 to 11 carbon atoms which may have a substituent, or a linear or branched saturated or unsaturated hydrocarbon group or saturated cyclic hydrocarbon group which may have a saturated ring structure and which may be substituted with one or more aryl groups which may have a substituent; r in the case where no heterocyclic ring is formed²³And R²⁵Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms;

wherein the symbols in formula (II) are as follows,

each of the rings Z is independently a 5-or 6-membered ring having 0 to 3 hetero atoms in the ring and which may be substituted,

R¹and R²、R²And R³And R¹And the carbon atoms or hetero atoms constituting the ring Z may be linked to each other and form, together with the nitrogen atom, eachHeterocycle A1, heterocycle B1 and heterocycle C1, in which case R is not a heterocycle¹And R²Each independently represents a hydrogen atom, a halogen atom, or a hydrocarbon group which may have an unsaturated bond, a hetero atom, a saturated or unsaturated ring structure between carbon atoms and which may have a substituent, R³And R⁴Each independently represents a hydrogen atom, a halogen atom, or an alkyl group which may contain a hetero atom between carbon atoms or an alkoxy group which may contain a hetero atom between carbon atoms,

wherein the symbols in formula (III) are as follows,

R⁵¹each independently represents a halogen atom or an alkyl group having 1 to 3 carbon atoms which may have a substituent,

R⁵²～R⁵⁸each independently represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 10 carbon atoms which may have a substituent,

R⁵²and R⁵³May 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 may be substituted with an alkyl group having 1 to 10 carbon atoms,

R⁵⁴and R⁵⁵Can be linked to each other to form a benzene ring A2, and the hydrogen atom of the benzene ring A2 can be substituted by an alkyl group having 1 to 10 carbon atoms.

8. The optical filter according to any one of claims 1 to 7, wherein the near-infrared absorbing dye (A) comprises at least two of a cyanine dye represented by the following formula (A11), a cyanine dye represented by the following formula (A12) or (A21), and a cyanine dye represented by the following formula (A22),

wherein the symbols in the formula (A11), the formula (A12), the formula (A21) and the formula (A22) are as follows,

R¹⁰¹～R¹⁰⁹、R¹¹⁵～R¹²⁰、R¹²¹～R¹³¹and R¹³⁷～R¹⁴²Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 15 carbon atoms which may have a substituent, an alkoxy group having 1 to 15 carbon atoms which may have a substituent, or an aryl group having 5 to 20 carbon atoms which may have a substituent; r^110～114And R^132～136Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 15 carbon atoms or an alkoxy group having 1 to 15 carbon atoms,

plural R contained in each formula¹⁰¹～R¹⁰⁹And a plurality of R¹²¹～R¹³¹May be the same as each other, may be different from each other,

X^-represents a monovalent anion.

9. An imaging device having the optical filter according to any one of claims 1 to 8.

Technical Field

The present invention relates to an optical filter that transmits light in a visible wavelength range and blocks light in a near infrared wavelength range, and an imaging device having the same.

Background

In an imaging device using a solid-state imaging element, in order to reproduce a color tone well and obtain a clear image, a filter which transmits light in a visible light region (hereinafter also referred to as "visible light") and blocks light in a near infrared region (hereinafter also referred to as "near infrared light") is used. As this filter, a near infrared cut filter having an absorption layer containing a near infrared absorber and a reflection layer including a dielectric multilayer film that blocks near infrared light is known. That is, since the spectral transmittance curve of the dielectric multilayer film itself changes according to the incident angle, the near-infrared cut filter including both the reflective layer and the absorbing layer can obtain a spectral transmittance curve in which the incident angle dependency is suppressed by the absorption characteristics of the absorbing layer.

In recent years, with the miniaturization and high quality of imaging devices, there is a demand for suppressing the incident angle dependence on light incident at higher angles. For example, it is required to increase the transmittance of near infrared light to be obtained with high reflectance in the wavelength range of 800nm to 900nm at a high incident angle and to suppress the occurrence of light leakage.

Many techniques for using an absorber that exhibits absorption in a wavelength range of 800nm to 900nm have been known for near-infrared cut filters. Specifically, it is known to use inorganic absorbents such as copper microparticles (for example, patent document 1), cyanine dyes (for example, patent documents 2 to 4), diimmonium dyes (for example, patent document 5), phthalocyanine dyes (for example, patent documents 6 and 7), and squaraine dyes

A pigment such as a salt-based pigment (for example, patent document 8). Furthermore, it is known, for example, to add squaric acidSalt-type pigments in combination with cyanine-type pigments, phthalocyanine-type pigments, and the like (for example, patent documents 9 and 10); a near-infrared cut filter such as a combination of a porphyrazine dye and a diimmonium dye (for example, patent document 11).

Disclosure of Invention

Problems to be solved by the invention

However, none of the above near-infrared cut filters can achieve both high transmittance of visible light and suppression of light leakage in a range of 800nm to 900nm in wavelength of light at a high incident angle at a high level.

The purpose of the present invention is to provide an optical filter that suppresses a decrease in the near-infrared light blocking property, particularly the near-infrared light blocking property at high incidence angles, while maintaining good visible light transmittance, and an imaging device that uses the optical filter and has excellent color reproducibility.

Means for solving the problems

An optical filter according to an embodiment of the present invention has the following features: the optical filter comprises an absorption layer and a reflection layer, wherein the absorption layer contains a near-infrared ray absorbing dye (A) and a transparent resin, the near-infrared ray absorbing dye (A) satisfies the following (i-1) to (i-5), and the optical filter satisfies the following (ii-1):

(i-1) a maximum absorption wavelength λ in a spectral transmittance curve at a wavelength of 400nm to 1100nm measured by including the near infrared ray absorbing dye (A) in the transparent resin_{Maximum (A) TR}In the wavelength range of 760nm to 900nm,

(i-2) at a wavelength such that the absorption maximum is λ_{Maximum (A) TR}An average transmittance T of light in a wavelength range of 435 to 480nm in a spectral transmittance curve of 400 to 1100nm measured with the near infrared ray absorbing dye (A) contained in the transparent resin so that the transmittance of the near infrared ray absorbing dye (A) is 10%_435-And an average transmittance T of light in a wavelength range of 480nm to 590nm_480-The content of the active ingredients is more than 90 percent,

(i-3) maximum absorption wavelength λ in spectral transmittance curve of 400nm to 1100nm wavelength measured by dissolving the near infrared ray absorbing dye (A) in methylene chloride_{Maximum (A) DCM}In the wavelength range of 760nm to 900nm,

(i-4) at a wavelength such that the absorption maximum is λ_{Maximum (A) DCM}An average transmittance T of light in a wavelength range of 435 to 480nm in a spectral transmittance curve of 400 to 1100nm measured with the near infrared ray absorbing dye (A) contained in methylene chloride so that the transmittance of the dye (A) is 10%_435-95% or more and an average transmittance T of light in a wavelength range of 480 to 590nm_480-The content of the active carbon is more than 97 percent,

(i-5) average Transmission T_435-And average transmission T_435-Difference between the values and average transmittance T_480-And average transmission T_480-The difference is 10.5% or less,

(ii-1) an average transmittance of light in a wavelength range of 800nm to 900nm at an incident angle of 60 degrees of 5% or less.

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

Effects of the invention

According to the present invention, a filter can be obtained in which the reduction in the near-infrared light blocking property, particularly the near-infrared light blocking property at a high incident angle, is suppressed while the transmittance of visible light is maintained favorably. Further, according to the present invention, an imaging device excellent in color reproducibility using the filter can be provided.

Drawings

Fig. 1 is a cross-sectional view schematically showing an example of an optical filter according to an embodiment.

Fig. 2 is a cross-sectional view schematically showing another example of the optical filter of one embodiment.

Fig. 3 is a cross-sectional view schematically showing another example of the optical filter of one embodiment.

Fig. 4 is a cross-sectional view schematically showing another example of the optical filter of one embodiment.

Fig. 5 is a cross-sectional view schematically showing another example of the optical filter of one embodiment.

Fig. 6 is a cross-sectional view schematically showing another example of the optical filter of one embodiment.

Detailed Description

Hereinafter, embodiments of the present invention will be described.

In the present specification, the near infrared absorbing dye may be simply referred to as "NIR dye" and the ultraviolet absorbing dye may be simply referred to as "UV dye".

In the present specification, a compound represented by formula (I) is referred to as compound (I). The same applies to compounds represented by other formulae. The dye containing the compound (I) is referred to as a dye (I), and the same applies to other dyes. For example, a compound represented by the formula (a1) described below is referred to as a compound (a1), and a dye containing the compound is referred to as a dye (a 1). For example, a group represented by the formula (1x) is referred to as a group (1x), and groups represented by other formulae are also the same.

In the present specification, for a specific wavelength range, a transmittance of, for example, 90% or more means a transmittance of not less than 90% over the entire wavelength range, and similarly, a transmittance of, for example, 1% or less means a transmittance of not more than 1% over the entire wavelength range. The average transmittance in a specific wavelength range is the arithmetic average of the transmittance per 1nm in that wavelength range.

In the present specification, "to" indicating a numerical range includes an upper limit and a lower limit.

In the present specification, when a plurality of substituents represented by the same symbol are present in a certain general formula, these plurality of substituents may be the same as or different from each other.

< Filter >

An optical filter according to one embodiment of the present invention (hereinafter also referred to as "the present optical filter") includes an absorption layer containing a pigment (a) which satisfies the following (i-1) to (i-5) and is an NIR pigment, and a reflection layer, and the optical filter satisfies the following (ii-1).

(i-1) maximum absorption wavelength λ in spectral transmittance curve of 400nm to 1100nm wavelength measured by including dye (A) in the transparent resin_{Maximum (A) TR}In the wavelength range of 760nm to 900 nm.

(i-2) at a wavelength such that the absorption maximum is λ_{Maximum (A) TR}An average transmittance T of light in a wavelength range of 435nm to 480nm in a spectral transmittance curve of 400nm to 1100nm measured with the dye (A) contained in the transparent resin so that the transmittance of the dye (A) is 10%_435-And an average transmittance T of light in a wavelength range of 480nm to 590nm_480-All are more than 90%.

(i-3) maximum absorption wavelength λ in spectral transmittance curve of wavelength 400nm to 1100nm measured by dissolving dye (A) in methylene chloride_{Maximum (A) DCM}In the wavelength range of 760nm to 900 nm.

(i-4) at a wavelength such that the absorption maximum is λ_{Maximum (A) DCM}The average transmittance T of light in the wavelength range of 435nm to 480nm in the spectral transmittance curve of 400nm to 1100nm measured with the dye (A) contained in methylene chloride so that the transmittance of the dye (A) is 10%_435-95% or more and an average transmittance T of light in a wavelength range of 480 to 590nm_480-Is more than 97%.

(i-5) average transmittance T of dye (A)_435-And average transmission T_435-Difference between the values and average transmittance T_480-And average transmission T_480-The difference is 10.5% or less.

(ii-1) the average transmittance of the filter for light in a wavelength range of 800nm to 900nm at an incident angle of 60 degrees is 5% or less.

The absorption layer contains the dye (A) having the characteristics of (i-1) to (i-5) and the transparent resin, and thus the filter is excellent in the light-shielding property of near infrared light and has high visible light transmittance. Further, the present filter can thereby suppress (ii-1) characteristics, that is, incident angle dependence on light incident at a high angle due to the provision of the reflective layer. In other words, the decrease in the near-infrared light blocking property at a high incident angle can be suppressed.

The dye (A) preferably further has the following characteristics (i-6). (i-6) the mass extinction coefficient when the dye (A) is contained in the transparent resin is 1900/(cm. mass%) or more.

The mass extinction coefficient can be calculated by calculating the internal transmittance T [% ] of light at the maximum absorption wavelength in the range of 350nm to 1200nm](% measured transmission [)]/(% 100-measured reflectance [)])×100[％]) And pass-log₁₀(T/100) calculating. Hereinafter, unless otherwise specified, the "mass extinction coefficient" of the pigment is the mass extinction coefficient calculated by the above-described method.

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

The filter may also have other functional layers. As another functional layer, for example, an antireflection layer that suppresses the transmittance loss of visible light can be cited. In particular, in the case where the absorption layer has an outermost surface structure, since a visible light transmittance loss due to reflection occurs at an interface between the absorption layer and air, an antireflection layer may be provided on the absorption layer.

Next, a configuration example of the present filter will be described with reference to the drawings. Fig. 1 shows an example of the structure of an optical filter 10A having a reflective layer 12 on one principal surface of an absorption layer 11. In the optical filter 10A, the absorption layer 11 may be formed of a layer containing the dye (a) and a transparent resin. Note that "the reflective layer 12 is provided on (on) one main surface of the absorption layer 11" includes not only the case where the reflective layer 12 is provided so as to be in contact with the absorption layer 11 but also the case where another functional layer is provided between the absorption layer 11 and the reflective layer 12, and the following configuration is also the same.

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 filter 10B includes a transparent substrate 13, an absorption layer 11 disposed on one main surface of the transparent substrate 13, and a reflection layer 12 provided on the other main surface of the transparent substrate 13. In the optical filter 10B, the absorption layer 11 may be formed of a layer containing the dye (a) and a transparent resin.

Fig. 3 shows an example of the structure of a filter 10C having an absorption layer 11 and having reflection layers 12a and 12b on both principal surfaces of the absorption layer 11.

Fig. 4 shows a configuration example of an optical filter 10D having an absorption layer 11 on one main surface of a 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.

Fig. 5 shows an example of the structure of a filter 10E having absorption layers 11a and 11b on both principal surfaces of a transparent substrate 13 and reflection layers 12a and 12b on the principal surfaces of the absorption layers 11a and 11 b.

In fig. 3, 4 and 5, the two combined reflective layers 12a, 12b may be the same or different. For example, the following configuration is possible: the reflective layers 12a, 12b have a property of reflecting ultraviolet light and near-infrared light and transmitting visible light, the reflective layer 12a reflects ultraviolet light and light of a first near-infrared region, and the reflective layer 12b reflects ultraviolet light and light of a second near-infrared region.

In fig. 5, the two absorption layers 11a and 11b may be the same or different. In the case where the absorbing layers 11a and 11b are different, for example, the absorbing layers 11a and 11b may be a combination of a near infrared ray absorbing layer and an ultraviolet ray absorbing layer, or a combination of an ultraviolet ray absorbing layer and a near infrared ray absorbing layer.

Fig. 6 shows an example of the structure of the optical filter 10F having the antireflection layer 14 on the main surface of the absorption layer 11 of the optical filter 10B shown in fig. 2. In the case of a structure in which a reflective layer is not provided and an absorbing layer is the outermost surface, an antireflection layer may be provided on the absorbing layer. Note that the antireflection layer may have a structure covering not only the outermost surface of the absorption layer but also the entire side surface of the absorption layer. In this case, the moisture-proof effect of the absorbent layer can be improved.

The absorbing layer, the reflective layer, the transparent substrate, and the antireflection layer will be described below.

(absorbing layer)

The absorption layer contains a dye (A) having the characteristics of (i-1) to (i-5) above, and preferably also having the characteristics of (i-6) above, and a transparent resin.

The absorption layer is typically a layer or a (resin) substrate in which the pigment (a) is uniformly dissolved or dispersed in a transparent resin. The absorbing layer may contain other NIR pigment than the pigment (a) within a range not to impair the effects of the present invention. Further, the absorbing layer may contain a pigment other than NIR pigment, particularly UV pigment, within a range not to impair the effects of the present invention.

As the other NIR dye, a dye (D) satisfying the following condition (iii-1) is preferably contained.

(iii-1) a maximum absorption wavelength λ in a spectral transmittance curve of 400nm to 1100nm wavelength measured by including a dye (D) in the transparent resin_{Maximum (D) TR}In the wavelength range of 680nm to 750 nm.

The pigment (D) preferably satisfies the following condition (iii-2). (iii-2) at a wavelength λ of maximum absorption_{Maximum (D) TR}The transmittance of (2) is 10% or more, and the average transmittance of light in a wavelength range of 400nm to 500nm is 85% or more in a spectral transmittance curve of 400nm to 1100nm measured with the dye (D) contained in the transparent resin.

Further, in the spectral transmittance curve of the internal transmittance at a wavelength of 350nm to 1200nm measured by including the dye (D) in the transparent resin, λ is_{Maximum (D) TR}An absorption peak having an absorption peak (hereinafter referred to as "λ_{Maximum (D) TR}Absorption peak of (b) is steep, that is, the wavelength from 70% transmittance to 20% transmittance is preferably 60nm or less, and more preferably 50nm or less, with respect to the slope on the visible light side.

[ coloring matter (A) ]

For the dye (A), the maximum absorption wavelength λ in (i-1)_{Maximum (A) TR}In the wavelength range of 760nm to 900 nm. Maximum absorption wavelength λ_{Maximum (A) TR}Preferably in the wavelength range of 760nm to 860 nm.

(ii) the average transmittance T of the dye (A) in (i-2)_{435-480 average (A) TR}And average transmission T_480-All are more than 90%. Average transmission T_435-Preferably 91% or more, and an average transmittance T_480-Preferably 92% or more.

For the dye (A), the maximum absorption wavelength λ in (i-3)_{Maximum (A) DCM}In the wavelength range of 760nm to 900 nm. Maximum absorption wavelength λ_{Maximum (A) DCM}Preferably in the wavelength range of 760nm to 860 nm.

(ii) the average transmittance T of the dye (A) in (i-4)_435-Is 95% or more, and has an average transmittance T_480-Is more than 97%. Average transmission T_435-Preferably 97% or more, and an average transmittance T_480-Preferably 99% or more.

(ii) the average transmittance T of the dye (A) in (i-5)_435-And average transmission T_435-Difference between the values and average transmittance T_480-And average transmission T_480-The difference is 10.5% or less. Average transmission T_435-And average transmission T_435-The difference is preferably 7% or less, and the average transmittance T_480-And average transmission T_480-The difference is preferably 5% or less.

The pigment (a) satisfying (i-5) means that the visible light transmittance in methylene chloride can be maintained even in a transparent resin when used in the form of a filter. In general, it is known that a pigment having a large maximum absorption wavelength is difficult to reproduce a sharp spectrum in methylene chloride in a transparent resin due to the effect of association. The dye (A) satisfies the above (i-1) to (i-5), and exhibits the following characteristics: the optical absorption characteristics are maintained even in a transparent resin while having optical absorption characteristics in which the maximum absorption wavelength is large and the visible light transmittance in methylene chloride is high.

The mass extinction coefficient of the dye (A) in (i-6) is 1900/(cm. mass%) or more. The mass extinction coefficient is preferably 2000/(cm · mass%) or more.

The molecular structure of the dye (A) is not particularly limited as long as the requirements (i-1) to (i-5) are satisfied. Specifically, cyanine dyes are mentioned. More specifically, the dye (a) is preferably a cyanine dye represented by the following formula (a1) or the following formula (a 2).

The symbols in the formulae (a1) and (a2) are as follows.

R¹⁰¹～R¹⁰⁹And R¹²¹～R¹³¹Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 15 carbon atoms which may have a substituent, an alkoxy group having 1 to 15 carbon atoms which may have a substituent, or an aryl group having 5 to 20 carbon atoms which may have a substituent. R¹¹⁰～¹¹⁴And R^132～136Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 15 carbon atoms, or an alkoxy group having 1 to 15 carbon atoms.

Plural R contained in each formula¹⁰¹～R¹⁰⁹And a plurality of R¹²¹～R¹³¹May be the same as or different from each other.

X^-Represents a monovalent anion.

n1 and n2 are 0 or 1. Bonded to a radical containing- (CH)₂)_n1A carbocyclic ring of and containing- (CH)₂)_n2The hydrogen atom on the carbon ring of (E) may be substituted with a halogen atom, an alkyl group having 1 to 15 carbon atoms which may have a substituent, or an aryl group having 5 to 20 carbon atoms which may have a substituent.

In the above, the alkyl group (including the alkyl group of the alkoxy group) may be a straight chain, or may have a branched structure or a saturated ring structure. The aryl group means a group bonded through a carbon atom constituting an aromatic ring of the aromatic compound, for example, a benzene ring, a naphthalene ring, biphenyl, a furan ring, a thiophene ring, a pyrrole ring, or the like. Examples of the substituent for the alkyl group having 1 to 15 carbon atoms which may have a substituent, the alkoxy group having 1 to 15 carbon atoms which may have a substituent, or the aryl group having 5 to 20 carbon atoms which may have a substituent include a halogen atom and an alkoxy group having 1 to 10 carbon atoms.

In the formulae (A1) and (A2), R¹⁰²～R¹⁰⁵、R¹⁰⁸、R¹⁰⁹、R¹²²～R¹²⁷、R¹³⁰And R¹³¹Each independently preferably a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, an alkoxy group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms, and more preferably a hydrogen atom from the viewpoint of obtaining high visible light transmittance.

In the formulae (A1) and (A2), R¹¹⁰～R¹¹⁴And R¹³²～R¹³⁶Each independently preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms, and more preferably a hydrogen atom from the viewpoint of obtaining high visible light transmittance.

R¹⁰⁶、R¹⁰⁷、R¹²⁸And R¹²⁹Each independently preferably represents a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms (which may include a chain, cyclic, or branched alkyl group), and more preferably represents a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. In addition, R¹⁰⁶And R¹⁰⁷、R¹²⁸And R¹²⁹Preferably the same group.

R¹⁰¹And R¹²¹Preferably an alkyl group having 1 to 15 carbon atoms or an aryl group having 5 to 20 carbon atoms, and more preferably an alkyl group having 1 to 15 carbon atoms having a branch chain, from the viewpoint of maintaining the visible light transmittance in the transparent resin as high as that in a solution.

As X^-Examples thereof include^-、BF₄ ^-、PF₆ ^-、ClO₄ ^-Anions represented by the formula (X1) and anions represented by the formula (X2), etc., preferably BF₄ ^-Or PF₆ ^-。

In the following description, reference will be made toR removal in pigment (A1)¹⁰¹～R¹¹⁴The other part is also called a skeleton (a 1). The same applies to other pigments.

The following formula (a11) shows a compound in which n1 is 1 in formula (a1), and the following formula (a12) shows a compound in which n1 is 0 in formula (a 1).

In the formulae (A11) and (A12), R¹⁰¹～R¹¹⁴And X^-The same as in the case of the formula (A1). R¹¹⁵～R¹²⁰Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 15 carbon atoms which may have a substituent, an alkoxy group having 1 to 15 carbon atoms which may have a substituent, or an aryl group having 5 to 20 carbon atoms which may have a substituent. Preferably a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms (which may include a chain, cyclic or branched alkyl group), more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. In addition, R¹¹⁵～R¹²⁰Preferably the same group.

The following formula (a21) shows a compound in which n2 is 1 in formula (a2), and the following formula (a22) shows a compound in which n2 is 0 in formula (a 2).

In the formulae (A21) and (A22), R¹²¹～R¹³⁶And X-is the same as in the case of the formula (A2). R¹³⁷～R¹⁴²Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 15 carbon atoms which may have a substituent, an alkoxy group having 1 to 15 carbon atoms which may have a substituent, or an aryl group having 5 to 20 carbon atoms which may have a substituent. Preferably a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms (which may include a chain, cyclic or branched alkyl group), more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. In addition, R¹³⁷～R¹⁴²Preferably the same group.

The compounds represented by each of formula (a11), formula (a12), formula (a21) and formula (a22) include, more specifically, compounds in tables 1 to 4 below in which atoms or groups bonded to each skeleton are shown. In all the compounds shown in tables 1 and 2, R is¹⁰¹～R¹⁰⁹The same applies to the right and left of the formula. In all the compounds shown in tables 3 and 4, R is¹²¹～R¹³¹The same applies to the left and right of the formula. In tables 1 to 4, only the bilaterally symmetrical compounds are shown, but the present invention is not limited thereto and may be bilaterally asymmetrical compounds. Asymmetric compounds have the advantage of improved solubility in resins.

R in tables 1 and 2¹¹⁰～R¹¹⁴And R in tables 3 and 4¹³²～R¹³⁶Represents an atom or a group bonded to the central benzene ring of each formula, and is described as "H" when all 5 atoms are hydrogen atoms. At R¹¹⁰～R¹¹⁴When any one of the substituents is a substituent and the other is a hydrogen atom, only the symbol as the substituent and the combination of the substituents are described. For example, "R¹¹²-C(CH₃)₃"is described as R¹¹²is-C (CH)₃)₃And the others are hydrogen atoms. For R¹³²～R¹³⁶The same applies.

R in Table 1¹¹⁵～R¹²⁰And R in Table 3¹³⁷～R¹⁴²Represents an atom or a group bonded to the cyclohexane ring at the center in formula (a11) or formula (a21), and is described as "H" when all 6 atoms are hydrogen atoms. At R¹¹⁵～R¹²⁰When any one of the substituents is a substituent and the other is a hydrogen atom, only the symbol as the substituent and the combination of the substituents are described. For R¹³⁷～R¹⁴²The same applies.

R in Table 2¹¹⁵～R¹¹⁸And R in Table 4¹³⁷～R¹⁴⁰Represents an atom or a group bonded to the central cyclopentane ring in the formula (a12) or the formula (a22), and is described as "H" when 4 atoms are all hydrogen atoms. At R¹¹⁵～R¹¹⁸When any one of the substituents is a substituent and the other is a hydrogen atom, only the symbol as the substituent and the combination of the substituents are described. For R¹³⁷～R¹⁴⁰The same applies.

Although X is not shown in tables 1 to 4^-However, in any one of the compounds X^-Is BF₄ ^-Or PF₆ ^-. X in the pigment (A11-1)^-Is BF₄ ^-The case (A) is represented by the dye (A11-1B), and X in the dye (A11-1)^-Is PF₆ ^-The case (A) is represented by the pigment (A11-1P). The same applies to other pigments shown in tables 1 to 4. In tables 1 to 4, -C₃H₇and-C₄H₉Respectively represent a linear propyl group and a butyl group.

Among the pigments (A11), from the viewpoints of solubility in a transparent resin, solubility in a solvent (hereinafter, also referred to as "main solvent") used when forming an absorption layer on a transparent substrate, and visible light transmittance, preferred are pigments (A11-1B), pigments (A11-1P), pigments (A11-2B), pigments (A11-2P), pigments (A11-3B), pigments (A11-3P), pigments (A11-4B), pigments (A11-4P), pigments (A11-5B), and pigments (A11-5P).

Among the pigments (A12), from the viewpoints of solubility in a transparent resin, solubility in a solvent (hereinafter, also referred to as "main solvent") used when forming an absorption layer on a transparent substrate, and visible light transmittance, preferred are pigments (A12-1B), pigments (A12-1P), pigments (A12-2B), pigments (A12-2P), pigments (A12-3B), pigments (A12-3P), pigments (A12-4B), pigments (A12-4P), pigments (A12-5B), and pigments (A12-5P).

Among the pigments (A21), from the viewpoints of solubility in a transparent resin, solubility in a solvent (hereinafter, also referred to as "main solvent") used when forming an absorption layer on a transparent substrate, and visible light transmittance, preferred are pigments (A21-1B), pigments (A21-1P), pigments (A21-2B), pigments (A21-2P), pigments (A21-3B), pigments (A21-3P), pigments (A21-4B), pigments (A21-4P), pigments (A21-5B), and pigments (A21-5P).

Among the pigments (A22), from the viewpoints of solubility in a transparent resin, solubility in a solvent (hereinafter, also referred to as "main solvent") used when forming an absorption layer on a transparent substrate, and visible light transmittance, preferred are pigments (A22-1B), pigments (A22-1P), pigments (A22-2B), pigments (A22-2P), pigments (A22-3B), pigments (A22-3P), pigments (A22-4B), pigments (A22-4P), pigments (A22-5B), and pigments (A22-5P).

The dye (a1) and the dye (a2) have different skeletons as described above, and thus have different maximum absorption wavelengths λ_{Maximum (A) TR}Are different in wavelength range. The maximum absorption wavelength λ of the pigment (A1) depends on the kind or combination of atoms or groups bonded to the skeleton (A1)_{Maximum (A1) TR}In the wavelength range of about 760nm to about 830 nm. The maximum absorption wavelength λ of the pigment (A2) depends on the kind or combination of atoms or groups bonded to the skeleton (A2)_{Maximum (A2) TR}In the wavelength range of about 800nm to about 900 nm.

In addition, with respect to the dye (a1), when n1 of the skeleton (a1) is 1 and when n1 is 0, the maximum absorption wavelength λ is_{Maximum (A1) TR}Different. The maximum absorption wavelength λ of the pigment (A11) depends on the kind or combination of atoms or groups bonded to the skeleton (A11)_{Maximum (A11) TR}In the wavelength range of about 760nm to about 800 nm. In addition, for the pigment (A12)In other words, although depending on the kind or combination of atoms or groups bonded to the skeleton (A12), the maximum absorption wavelength λ_{Maximum (A12) TR}In the wavelength range of about 800nm to about 830 nm.

Similarly, with respect to the dye (a2), when n2 is 1 and n2 is 0, the maximum absorption wavelength λ is_{Maximum (A2) TR}And also different. The maximum absorption wavelength λ of the pigment (A21) depends on the kind or combination of atoms or groups bonded to the skeleton (A21)_{Maximum (A21) TR}In the wavelength range of about 800nm to about 830 nm. In addition, the dye (a22) has a maximum absorption wavelength λ depending on the kind or combination of atoms or groups bonded to the skeleton (a22)_{Maximum (A22) TR}In the wavelength range of about 830nm to about 900 nm.

The absorbing layer may contain one kind of the coloring matter (a) alone, or may contain two or more kinds of the coloring matters (a) in combination. When two or more kinds of the dye (A) are contained, the maximum absorption wavelength λ of each dye (A) is preferably_{Maximum (A) TR}Different. Maximum absorption wavelength λ of two or more kinds of the dye (A)_{Maximum (A) TR}The difference is, for example, preferably in the range of 20nm to 60nm, more preferably 30nm to 50 nm. When the pigment (a) contains two or more compounds, each compound does not necessarily have to have the property of the pigment (a), and the mixture may have the property of the pigment (a).

As a preferable combination of two or more kinds of the pigments (a), a pigment (a11) having a maximum absorption wavelength on the shorter wavelength side among the pigments (a) is referred to as a pigment S, a pigment (a22) having a maximum absorption wavelength on the longer wavelength side is referred to as a pigment L, and a pigment (a12) or a pigment (a21) having a maximum absorption wavelength between the maximum absorption wavelengths of the pigment S and the pigment L is referred to as a pigment M, and two or more kinds of the pigments S, M, and L are preferably selected and combined.

Specifically, there may be mentioned: a combination of pigment S and pigment M, a combination of pigment S and pigment L, a combination of pigment M and pigment L, and a combination of pigment S, pigment M and pigment L. The maximum absorption wavelength λ of the dye S_{Maximum (A) TR}Preferably 765 nm-785The wavelength range of nm is more preferably 770nm to 780 nm. Maximum absorption wavelength λ of dye M_{Maximum (A) TR}Preferably in the wavelength range of 795nm to 815nm, more preferably in the wavelength range of 800nm to 810 nm. Maximum absorption wavelength λ of dye L_{Maximum (A) TR}Preferably in the wavelength range of 820nm to 850nm, more preferably in the wavelength range of 830nm to 850 nm.

The dye (a1) and the dye (a2) can be produced by the methods described in, for example, dye and pigments (Dyes and pigments)73(2007) 344-. As the dye (A11-5P) and the dye (A21-5P), trade names S2138 and S2139 available from Few Chemicals, Inc. can be used.

[ coloring matter (D) ]

Examples of the pigment (D) include: selected from the group consisting of cyanine pigments, phthalocyanine pigments, naphthalocyanine pigments, dithiol metal complex pigments, diimmonium pigments, polymethine pigments, phthalide pigments, naphthoquinone pigments, anthraquinone pigments, indophenol pigments, squaraine pigments, which satisfy the requirement (iii-1), preferably further satisfy the requirement (iii-2)At least one pigment from the group consisting of salt pigments.

Among them, the squaraines satisfying the requirement (iii-1), preferably satisfying the requirement (iii-2) are particularly preferableSalt pigment. Containing squaric acid

The pigment (D) of the salt pigment has little absorption of visible light in the above absorption spectrum, and has a lambda of_{Maximum (D) TR}Has a steep slope on the visible light side, and is high in storage stability and stability against light.

As in squaric acid

A pigment (D) of a salt pigment,preferably lambda_{Maximum (D) TR}A compound represented by any one of formulae (I) to (III) in a wavelength range of 680nm to 750 nm. The mass extinction coefficient when the pigment (D) is contained in the transparent resin is preferably 1000/(cm. mass%), and more preferably 1500/(cm. mass%).

Wherein, the symbols in formula (I) are as follows.

R²⁴And R²⁶Each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyloxy group having 1 to 10 carbon atoms, -NR²⁷R²⁸(R²⁷And R²⁸Each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, -C (═ O) -R²⁹(R²⁹A hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an aryl group having 6 to 11 carbon atoms which may have a substituent, or a linear or branched saturated or unsaturated hydrocarbon group or saturated cyclic hydrocarbon group (アルアリ - ル group)) which may have a saturated ring structure and is substituted with one or more aryl groups having 7 to 18 carbon atoms which may have a substituent and may have an oxygen atom between carbon atoms, wherein the saturated or branched saturated or unsaturated hydrocarbon group or saturated cyclic hydrocarbon group may have a saturated ring structure³⁰or-SO₂-R³⁰(R³⁰A hydrocarbon group having 1 to 25 carbon atoms, each of which has at least one hydrogen atom which may be substituted with a halogen atom, a hydroxyl group, a carboxyl group, a sulfo group or a cyano group and may have an unsaturated bond, an oxygen atom or a saturated or unsaturated ring structure between carbon atoms), or a group represented by the following formula (S) (R)⁴¹、R⁴²Independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms. k is 2 or 3).

R²¹And R²²、R²²And R²⁵And R²¹And R²³May be linked to each other and form, together with the nitrogen atom, a five-or six-membered heterocycle A, a heterocycle B and a heterocycle C, respectively.

For R in the case of the formation of a heterocycle A²¹And R²²As R²¹And R²²The divalent group-Q-bonded represents an alkylene group in which a hydrogen atom may be substituted with an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an acyloxy group having 1 to 10 carbon atoms which may have a substituent, or an alkyleneoxy group in which a hydrogen atom may be substituted with an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an acyloxy group having 1 to 10 carbon atoms which may have a substituent.

For R in the case of the formation of a heterocyclic ring B²²And R²⁵And R in the case of the formation of a heterocycle C²¹And R²³As R²²And R²⁵And R²¹And R²³Each bonded divalent radical-X¹-Y¹-and-X²-Y²- (one side bound to nitrogen being X)¹And X²)，X¹And X²Each is a group represented by the following formula (1x) or (2x), Y¹And Y²Each is a group represented by any one selected from the following formulas (1y) to (5 y). At X¹And X²Y is a group represented by the following formula (2x)¹And Y²Each may be a single bond, in which case there may be an oxygen atom between the carbon atoms.

In the formula (1x), 4 Zs independently represent a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or-NR³⁸R³⁹(R³⁸And R³⁹Each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms). R³¹～R³⁶Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms, R³⁷Represents an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms.

R²⁷、R²⁸、R²⁹、R³¹～R³⁷R in the case where no heterocyclic ring is formed²¹～R²³And R²⁵May be bonded to each other with any of them to form a 5-or 6-membered ring. R³¹And R³⁶、R³¹And R³⁷The bonding may be direct.

R in the case where no heterocyclic ring is formed²¹And R²²Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, an allyl group which may have a substituent, an aryl group having 6 to 11 carbon atoms which may have a substituent, or a linear or branched saturated or unsaturated hydrocarbon group or saturated cyclic hydrocarbon group which may have a saturated ring structure and which may be substituted with one or more aryl groups which may have a substituent. R in the case where no heterocyclic ring is formed²³And R²⁵Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

Wherein, the symbols in formula (II) are as follows.

Each of the rings Z is independently a 5-or 6-membered ring having 0 to 3 hetero atoms in the ring and which may be substituted.

R¹And R²、R²And R³And R¹And the carbon atoms or heteroatoms constituting the ring Z may be linked to each other and form, together with the nitrogen atom, a heterocycle A1, a heterocycle B1 and a heterocycle C1, respectively, in the case where no heterocycle is formed, R¹And R²Each independently represents a hydrogen atom, a halogen atom, or a hydrocarbon group which may have an unsaturated bond, a hetero atom, a saturated or unsaturated ring structure between carbon atoms and which may have a substituent, R³And R⁴Each independently represents a hydrogen atom, a halogen atom, or an alkyl group which may contain a hetero atom between carbon atoms or an alkoxy group which may contain a hetero atom between carbon atoms.

Wherein, the symbols in formula (III) are as follows.

R⁵¹Each independently represents a halogen atom or an alkyl group having 1 to 3 carbon atoms which may have a substituent,

R⁵²～R⁵⁸each independently represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 10 carbon atoms which may have a substituent.

R⁵²And R⁵³May 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 may be substituted with an alkyl group having 1 to 10 carbon atoms,

R⁵⁴and R⁵⁵Can be linked to each other to form a benzene ring A2, and the hydrogen atom of the benzene ring A2 can be substituted by an alkyl group having 1 to 10 carbon atoms.

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

The symbols in the formulae (I-1) to (I-4) are as defined above for the same symbols in the formula (I), and the preferred embodiments are the same.

Among the compounds (I-1) to (I-4), the dye (A) is preferably the compounds (I-1) to (I-3), particularly preferably the compound (I-1), from the viewpoint of improving the visible light transmittance of the absorption layer.

In the compound (I-1), as X¹Preference is given to the radical (2x) as Y¹Preferably a single bond or a group (1 y). In this case, as R³¹～R³⁶The alkyl group is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom or a methyl group. In addition, as-Y¹-X¹Specific examples thereof include divalent organic groups represented by the formulae (11-1) to (12-3).

-C(CH₃)₂-CH(CH₃)- (11-1)

-C(CH₃)₂-CH₂- (11-2)

-C(CH₃)₂-CH(C₂H₅)- (11-3)

-C(CH₃)₂-C(CH₃)(nC₃H₇)- (11-4)

-C(CH₃)₂-CH₂-CH₂- (12-1)

-C(CH₃)₂-CH₂-CH(CH₃)- (12-2)

-C(CH₃)₂-CH(CH₃)-CH₂- (12-3)

In the compound (I-1), R is R from the viewpoint of solubility, heat resistance and steepness of change in the vicinity of the boundary between the visible region and the near-infrared region in the spectral transmittance curve²¹More preferably independently a group represented by formula (4-1) or formula (4-2).

In the formulae (4-1) and (4-2), R⁷¹～R⁷⁵Independently represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms.

In the compound (I-1), R²⁴Is preferably-NR²⁷R²⁸. as-NR²⁷R²⁸From the viewpoint of solubility in the main solvent or the transparent resin, — NH — C (═ O) -R is preferable²⁹. Formula (I-11) shows that R in Compound (I-1)²⁴is-NH-C (═ O) -R²⁹The compound of (1).

R in Compound (I-11)²³And R²⁶Independently preferably a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms or a C1 to EThe alkoxy groups of 6 are more preferably all hydrogen atoms.

In the compound (I-11), as R²⁹Preferably, the hydrocarbon group is a linear or branched saturated or unsaturated hydrocarbon group or a saturated cyclic hydrocarbon group which may have a saturated ring structure, and which may have a substituent(s) alkyl group having 1 to 20 carbon atoms, may have a substituent(s) aryl group having 6 to 10 carbon atoms, may have a substituent(s), or may have 7 to 18 carbon atoms and may have an oxygen atom(s) between the carbon atoms, and which may be substituted with one or more aryl groups. As the substituent, there may be mentioned: halogen atom such as fluorine atom, hydroxyl group, carboxyl group, sulfo group, cyano group, alkyl group having 1 to 6 carbon atoms, fluoroalkyl group having 1 to 6 carbon atoms, alkoxy group having 1 to 6 carbon atoms, acyloxy group having 1 to 6 carbon atoms, and the like.

As R²⁹Preferably a group selected from: a linear, branched or cyclic alkyl group having 1 to 17 carbon atoms which may be substituted with a fluorine atom, a phenyl group which may be substituted with a fluoroalkyl group having 1 to 6 carbon atoms and/or an alkoxy group having 1 to 6 carbon atoms, a phenyl group having 7 to 18 carbon atoms which may have an oxygen atom between carbon atoms and which may have a phenyl group substituted with an alkyl group having 1 to 6 carbon atoms which may be substituted with a fluorine atom and/or an alkoxy group having 1 to 6 carbon atoms at the terminal, a linear or branched saturated or unsaturated hydrocarbon group or a saturated cyclic hydrocarbon group which may have a saturated ring structure and which may be substituted with one or more aryl groups.

As R²⁹Independently, the following groups may be preferably used: and a hydrocarbon group having 5 to 25 carbon atoms, which has at least one branched chain and in which one or more hydrogen atoms may be substituted with a halogen atom, a hydroxyl group, a carboxyl group, a sulfo group or a cyano group, and which may have an unsaturated bond, an oxygen atom or a saturated or unsaturated ring structure between carbon atoms. As such R²⁹Examples thereof include groups represented by the following formulas (1a), (1b), (2a) to (2e), and (3a) to (3 e).

More specifically, the compound (I-11) is a compound shown in Table 5 below. In Table 5, the group (11-1) is represented by (11-1). The same applies to other groups. The same applies to the groups in the other tables below. In addition, all compounds shown in table 5 are within the squaric acidThe symbols on the left and right sides of the salt skeleton have the same meaning. In the other squaric acids shown in the following tablesThe same applies to the salt pigment.

TABLE 5

In the compound (I-1), R is a group having a high transmittance for visible light, particularly for light having a wavelength of 430 to 550nm²⁴preferably-NH-SO₂-R³⁰. Formula (I-12) shows that R is in Compound (I-1)²⁴is-NH-SO₂-R³⁰The compound of (1).

R in Compound (I-12)²³And R²⁶Independently, the alkyl group is preferably a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms, and more preferably both hydrogen atoms.

In the compound (I-12), R is from the viewpoint of light resistance³⁰Independently, the alkyl group may have a branched C1-12 alkyl group, a branched C1-12 alkoxy group, or a C6-16 hydrocarbon group having an unsaturated ring structure. Examples of the unsaturated ring structure include benzene, toluene, xylene, and toluene,Furan, benzofuran, and the like. R³⁰Independently, the alkyl group may have a branched C1-12 alkyl group or the alkoxy group may have a branched C1-12 alkoxy group. In addition, in the formula R³⁰In each of the groups (a), a part or all of hydrogen atoms may be substituted with a halogen atom, particularly a fluorine atom. In the case where the present filter has a structure including a transparent substrate, the hydrogen atoms are substituted with fluorine atoms to such an extent that the adhesion between the absorption layer containing the dye (I-12) and the transparent substrate is not lowered.

R as a ring structure having unsaturation³⁰Specifically, groups represented by the following formulae (P1) to (P8) are included.

More specifically, the compounds shown in Table 6 below can be mentioned as the compound (I-12).

TABLE 6

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

Wherein, in the formula (II-1) and the formula (II-2), R¹And R²Each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 15 carbon atoms which may have a substituent, R³～R⁶Each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms which may have a substituent.

Wherein, in the formula (II-3), R¹、R⁴And R⁹～R¹²Each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 15 carbon atoms which may have a substituent,R⁷and R⁸Each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms which may have a substituent.

R in Compound (II-1) and Compound (II-2) from the viewpoints of solubility in a transparent resin, visible light transmittance and the like¹And R²Independently, the alkyl group is preferably an alkyl group having 1 to 15 carbon atoms, more preferably an alkyl group having 7 to 15 carbon atoms, and further preferably R¹And R²At least one of the above groups is a branched alkyl group having 7 to 15 carbon atoms, and R is particularly preferred¹And R²Both are C8-15 branched alkyl groups.

From the viewpoint of solubility in the transparent resin, visible light transmittance, and the like, R³Independently, the alkyl group is preferably a hydrogen atom, a halogen atom or an alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom, a halogen atom or a methyl group. From the viewpoint of steepness of change in the vicinity of the boundary between the visible region and the near-infrared region, R⁴Hydrogen atom or halogen atom is preferable, and hydrogen atom is particularly preferable. R in Compound (II-1)⁵And R in the Compound (II-2)⁶Independently, the alkyl group 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.

More specifically, the compounds (II-1) and (II-2) are those shown in the following tables 7 and 8. In tables 7 and 8, -C₈H₁₇、-C₄H₉、-C₆H₁₃Respectively represent a linear octyl group, a linear butyl group and a linear hexyl group.

TABLE 7

TABLE 8

From the front to the backR in Compound (II-3) from the viewpoint of improving solubility in resin, visible light transmittance and the like¹Independently, the alkyl group is preferably an alkyl group having 1 to 15 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms, and particularly preferably an ethyl group or an isopropyl group.

From the viewpoint of visible light transmittance and ease of synthesis, R⁴Hydrogen atom or halogen atom is preferable, and hydrogen atom is particularly preferable. R⁷And R⁸Independently, the alkyl group 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.

R⁹～R¹²Independently, a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms which may be substituted with a halogen atom is preferable. as-CR⁹R¹⁰-CR¹¹R¹²Examples thereof include the above-mentioned groups (11-1) to (11-3) and a divalent organic group represented by the following formula (11-5).

-C(CH₃)(CH₂-CH(CH₃)₂)-CH(CH₃)- (11-5)

More specifically, the compound (II-3) is a compound shown in Table 9 below.

TABLE 9

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

Wherein, in (III-1) and (III-2), R⁵²～R⁶²Each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms which may have a substituent.

In the compound (III-1) or the compound (III-2), R⁵²、R⁵³Independently preferably a hydrogen atom, a halogen atomOr an alkyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, and is more preferably a hydrogen atom, a halogen atom or a methyl group. R⁵⁸Preferably 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 more preferably an alkyl group having 1 to 3 carbon atoms from the viewpoint of ease of synthesis. R⁵⁶、R⁵⁷、R⁵⁹～R⁶²Each independently is preferably a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a substituent, and more preferably a hydrogen atom from the viewpoint of ease of synthesis. More specifically, the compounds (III-1) and (III-2) shown in tables 10 and 11 below are mentioned.

Watch 10

TABLE 11

The dye (D) may be composed of one kind of compound, or may be composed of two or more kinds of compounds. When the dye (D) is a dye having a dye-binding property, the dye (D) may be a dye having a dye-binding property.

The compounds (I) to (III) can be produced by known methods. Compound (I), compound (I-11) can be produced, for example, by the method described in the specification of U.S. Pat. No. 5543086. Compound (I-12) can be produced, for example, by the methods described in U.S. patent application publication No. 2014/0061505 and International publication No. 2014/088063. The compound (II) can be produced by the method described in international publication No. 2017/135359.

As the UV pigment, there can be mentioned:

azoles, their salts, and their use as medicaments,Merocyanines, cyanines, naphthalimides, and mixtures thereof,

A diazole,

Azines, their derivatives,Specific examples of the coloring matter include oxazolidines, naphthalic acids, styrenes, anthracenes, cyclic carbonyls, and triazoles. Among them, preferred isAzoles or merocyanines. In addition, one kind of UV dye may be used alone or two or more kinds of UV dyes may be used in combination in the absorption layer.

As the transparent resin, a transparent resin satisfying (i-1), (i-2) and (i-5) in relation to the pigment (A) is used.

The transparent resin may be one or more selected from acrylic resins, epoxy resins, ene thiol resins, polycarbonate resins, polyether resins, polyarylate resins, polysulfone resins, polyethersulfone resins, polyparaphenylene resins, polyaryletherphosphine oxide resins, polyimide resins, polyamideimide resins, polyolefin resins, cyclic olefin resins, polyester resins, and the like, depending on the type of the pigment (a).

Among them, the transparent resin is preferably a polyester resin, a polycarbonate resin, a polyimide resin, and an acrylic imide resin. These resins may be used singly or in combination of two or more. When the dye (a) is the dye (a1) or the dye (a2), a polyester resin, a polycarbonate resin, a polyimide resin, and an acrylic imide resin are particularly preferable.

As the transparent resin, commercially available products can be used. As a commercially available product, polyester resins include: OKP4, 4HT, OKP4, B-OKP2, OKP-850 (all of which are trade names of Katakawa gas chemical Co., Ltd.), VYLON (registered trademark) 103 (trade name of Toyo Boseki Kabushiki Kaisha), and the like.

As the polycarbonate resin, there may be mentioned: LeXan (registered trademark) ML9103 (trade name, manufactured by sabic corporation), EP5000 (trade name, manufactured by mitsubishi gas chemical corporation), SP3810 (trade name, manufactured by imperial corporation), SP1516 (trade name, manufactured by imperial corporation), TS2020 (trade name, manufactured by imperial corporation), xylex (registered trademark) 7507 (trade name, manufactured by sabic corporation), and the like.

As the polyimide resin, there can be mentioned: neopulim (registered trademark) C3650 (trade name, manufactured by Mitsubishi gas chemical Co., Ltd.), Neopulim (registered trademark) C3G30 (trade name, manufactured by Mitsubishi gas chemical Co., Ltd.), Neopulim (registered trademark) C3450 (trade name, manufactured by Mitsubishi gas chemical Co., Ltd.), JL-20 (trade name, manufactured by Nissan chemical Co., Ltd.), FPC-0220 (trade name, manufactured by Mitsubishi gas chemical Co., Ltd.) (these polyimide resins may contain silica), and the like. Examples of the acrylic imide resin include PLEXIMID8817 (trade name, manufactured by celluloid corporation).

From the viewpoint of transparency, solubility of the dye (a) and the dye (D), and heat resistance, the transparent resin is preferably a resin having a high glass transition temperature (Tg), for example, a Tg of 140 ℃.

The absorbing layer may further contain optional components such as a thickener, a color tone correction pigment, a leveling agent, an antistatic agent, a heat stabilizer, a light stabilizer, an antioxidant, a dispersant, a flame retardant, a lubricant, and a plasticizer within a range not to impair the effects of the present invention.

The present filter has the characteristics (ii-1) by the absorption layer containing the dye (A) having the characteristics (i-1) to (i-5) and the transparent resin. In other words, the dye (A) is a compound which can satisfy the characteristic of (ii-1) in the filter obtained when the dye is used.

(ii-1) average transmittance T of light in a wavelength range of 800nm to 900nm at an incident angle of 60 degrees_800-Is 5% or less. Average transmission T_800-Preferably 3% or less, more preferably 1% or less.

In the present filter, when the absorption layer contains the dye (D) in addition to the dye (A), the dye (D) is preferably a compound that satisfies the following requirements (ii-2) to (ii-6) when used together with the dye (A).

(ii-2) average transmittance T of the filter for light in a wavelength range of 435nm to 480nm at an incident angle of 0 degree_{435 and 480 average 0 degree}Is more than 70%.

(ii-3) average transmittance T of the filter for light in a wavelength range of 490nm to 580nm at an incident angle of 0 DEG_{490-580 average 0 °}Is over 84 percent.

(ii-4) average transmittance T of the filter for light in the wavelength range of 800nm to 900nm at an incident angle of 60 degrees_800-Is 1% or less.

(ii-5) maximum transmittance T of the filter for light in a wavelength range of 800nm to 900nm at an incident angle of 60 degrees_800-Is 10% or less.

(ii-6) wavelength λ on the short wavelength side of the wavelength of the filter exhibiting 20% transmittance at an incident angle of 0 degree_SHT20-0°A wavelength λ on the short wavelength side of a wavelength in the wavelength range of 640nm to 690nm and exhibiting a transmittance of 20% at an incident angle of 30 DEG_SHT20-30°And wavelength lambda_SHT20-0°The difference is 10nm or less.

Average transmittance T in (ii-2)_{435 and 480 average 0 degree}Preferably 75% or more, more preferably 77% or more. Average transmittance T in (ii-3)_{490-580 average 0 °}Preferably 85% or more, more preferably 87% or more. Average transmittance T in (ii-4)_800-Preferably 0.9% or less, more preferably 0.5% or less. (ii-5) maximum transmittance T_800-Preferably 8.5% or less, more preferably 5% or less. In (ii-6), the wavelength λ_SHT20-30°And wavelength lambda_SHT20-0°The difference is preferably 5nm or less, more preferably 3nm or less.

The content of the coloring matter (A) in the absorption layer is an amount that satisfies (ii-1) in the present filter according to the design of the present filter. The content of the pigment (a) in the absorbing layer is preferably 0.1 to 20 parts by mass per 100 parts by mass of the transparent resin, and the content of the pigment (a) in the absorbing layer is preferably 1 to 20 parts by mass from the viewpoint of solubility, from the viewpoint of ensuring the transmittance of visible light, blocking near infrared light, and suppressing incident angle dependence of the reflecting layer with respect to light incident at a high angle, particularly reducing light leakage in a wavelength range of 800 to 900nm at a high incident angle.

In the case where two or more selected from among the pigments S, M, and L are used in the pigment (a), the total content of all the pigments (a) is within the above range, and the content of each pigment is preferably 0.1 to 20 parts by mass, more preferably 1 to 20 parts by mass, relative to 100 parts by mass of the transparent resin.

When the absorption layer contains the pigment (a) and the pigment (D), the contents of the pigment (a) and the pigment (D) are each appropriately selected so as to satisfy the characteristics of (ii-2) to (ii-6) in accordance with the design of the present filter.

In this case, the content of the pigment (a) in the absorption layer is preferably 0.1 to 20 parts by mass, more preferably 1 to 20 parts by mass, per 100 parts by mass of the transparent resin, from the viewpoint of ensuring visible light transmittance and allowing the pigment (D) to exhibit its properties, as described above. The total content of the pigment (a) and the pigment (D) is preferably 0.1 to 20 parts by mass, more preferably 1 to 20 parts by mass, per 100 parts by mass of the transparent resin.

In the present filter, the thickness of the absorption layer is preferably 0.1 μm to 100. mu.m. When the absorbing layer includes a plurality of layers, the total thickness of the layers is preferably 0.1 μm 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 reduced, and in-plane variations in the absorptance may occur. The thickness of the absorption layer is more preferably 0.3 to 50 μm. In the case where another functional layer such as a reflective layer or an antireflection layer is provided, depending on the material, cracks or the like may occur when the absorption layer is too thick. Therefore, the thickness of the absorption layer is more preferably 0.3 μm to 10 μm.

The absorption layer can be formed, for example, by: the pigment (a), preferably the pigments (a) and (D), the transparent resin or the raw material components of the transparent resin, and if necessary, the respective components are dissolved or dispersed in a solvent to prepare a coating liquid, which is applied to a substrate and dried, and then cured if necessary. The substrate may be a transparent substrate included in the present optical filter, or may be a releasable substrate used only when the absorption layer is formed. The solvent may be a dispersion medium capable of stable dispersion or a solvent capable of dissolving.

The coating liquid may contain a surfactant in order to improve voids due to fine bubbles, depressions due to adhesion of foreign matters, and shrinkage during the drying step. For coating of the coating liquid, for example, a dip coating method, a casting coating method, a spin coating method, or the like can be used. The above coating liquid is applied on a substrate and then dried, thereby forming an absorption layer. When the coating liquid contains a raw material component of the transparent resin, curing treatment such as thermal curing or photo curing is further performed.

The absorbent layer may be formed into a film by extrusion molding, or the film may be laminated on another member and integrated by thermocompression bonding or the like. For example, when the present optical filter includes a transparent substrate, the film may be attached to the transparent substrate.

The filter may have one absorbing layer or two or more absorbing layers. In the case of having two or more absorbent layers, the respective layers may have the same or different configurations. In the case where the absorption layer contains the dye (a), the dye (D) and the UV dye, one layer may be a near-infrared absorption layer containing the dye (a), the dye (D) and a transparent resin, and the other layer may be a near-ultraviolet absorption layer containing the UV dye and a transparent resin. As another example, one layer may be a first near-infrared absorbing layer containing the pigment (D) and a transparent resin, and the other layer may be a second near-infrared absorbing layer containing the pigment (a), a UV pigment, and a transparent resin. In addition, the absorption layer itself may function as a substrate (resin substrate).

(transparent substrate)

When a transparent substrate is used in the present filter, the material of the transparent substrate is not particularly limited as long as the transparent substrate transmits visible light of about 400nm to about 700nm, and may be a material that absorbs near infrared light or near ultraviolet light. Examples thereof include inorganic materials such as glass and crystal, and organic materials such as transparent resins.

Examples of the glass that can be used for the transparent substrate include absorption glass (near-infrared ray absorption glass) containing copper ions in fluorophosphate-type glass, phosphate-type glass, and the like, soda-lime glass, borosilicate glass, alkali-free glass, quartz glass, and the like. The "phosphate glass" also includes a glass having a glass skeleton partially composed of SiO₂The formed silicon phosphate glass.

As the glass, chemically strengthened glass obtained by replacing alkali metal ions having a small ion radius (for example, Li ions and Na ions) present on the main surface of the glass plate with alkali metal ions having a large ion radius (for example, Na ions or K ions for Li ions and K ions for Na ions) by ion exchange at a temperature equal to or lower than the glass transition temperature can be used.

As transparent resin materials that can be used as the transparent substrate, there are listed: polyester resins such as polyethylene terephthalate and polybutylene terephthalate; polyolefin resins such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymers; acrylic resins such as norbornene resin, polyacrylate, and polymethyl methacrylate; polyurethane resin, vinyl chloride resin, fluorine-containing resin, polycarbonate resin, polyvinyl butyral resin, polyvinyl alcohol resin, polyimide resin, and the like.

Further, as a crystal material that can be used for the transparent substrate, birefringent crystals such as crystal, lithium niobate, and sapphire can be cited. As for the optical characteristics of the transparent substrate, a filter obtained by laminating the absorption layer, the reflection layer, and the like may have the optical characteristics. As the crystalline material, sapphire is preferable.

The transparent substrate is preferably made of an inorganic material, particularly preferably glass or sapphire, from the viewpoint of shape stability as a long-term reliability such as optical characteristics and mechanical characteristics of the filter, and from the viewpoint of handling properties during the production of the filter.

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

(reflection layer)

The reflective layer includes, for example, a dielectric multilayer film, and has a function of blocking light in a specific wavelength range. Examples of the reflective layer include: a wavelength selective layer that transmits visible light and mainly reflects light of wavelengths 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 further block light in a predetermined wavelength range, for example, light in a near ultraviolet region.

In the case where the reflective layer has a reflective region that reflects near-infrared light, the absorbing layer and the reflective layer preferably have the following relationship.

The absorption layer preferably has a wavelength λ on the short wavelength side of a wavelength at which light having an incident angle of 0 degrees exhibits a transmittance of 20%_ABSHT20-0°In the wavelength range of 650nm to 720 nm. And, preferably λ_ABSHT20-0°And λ_RESHT20-0°Satisfies the relationship of (iv-1), the λ_RESHT20-0°The reflection layer of the optical filter including the reflection layer has a wavelength on the short wavelength side of a wavelength at which a light having an incident angle of 0 degrees exhibits a transmittance of 20%.

(iv-1)λ_ABSHT20-0°+30nm≤λ_RESHT20-0°≤790nm

The reflective layer further preferably satisfies (iv-2).

(iv-2) slave λ of reflective layer_RESHT20-0°To lambda_RESHT20-0°The average transmittance of light in the wavelength range of +300nm is 10% or less.

In the present filter, since the absorption layer contains the dye (a), even when light enters the reflection layer at a high angle, the incident angle dependence of the reflection layer can be suppressed, and in particular, light leakage in the wavelength range of 800nm to 900nm at a high incident angle can be reduced.

The reflective layer is composed of a dielectric multilayer film obtained by alternately laminating a dielectric film having a low refractive index (low refractive index film) and a dielectric film having a high refractive index (high refractive index film). The refractive index of the high refractive index film is preferably 1.6 or more, and more preferably 2.2 to 2.5. As a material of the high refractive index film, for example, Ta₂O₅、TiO₂、Nb₂O₅. Among them, TiO is preferable from the viewpoints of film forming property, reproducibility of refractive index and the like, stability and the like₂。

On the other hand, the refractive index of the low refractive index film is preferably less than 1.6, and more preferably 1.45 or more and less than 1.55. Examples of the material of the low refractive index film include SiO₂、SiO_xN_yAnd the like. From the viewpoint of reproducibility, stability, economy and the like of film forming property, SiO is preferable₂。

Further, the transmittance of the reflective layer preferably changes steeply in the boundary wavelength range between the transmissive region and the light-shielding region. For this purpose, the total number of layers of the dielectric multilayer film constituting the reflective layer is preferably 15 or more, more preferably 25 or more, and still more preferably 30 or more. However, since a larger total number of layers causes warpage or increases the film thickness, the total number of layers is preferably 100 layers or less, more preferably 75 layers or less, and still more preferably 60 layers or less. The thickness of the dielectric multilayer film is preferably 2 to 10 μm.

If the total number of stacked dielectric multilayer films and the film thickness are within the above ranges, the reflective layer can satisfy the requirement of miniaturization, and the incidence angle dependence can be suppressed while maintaining high productivity. In the formation of the dielectric multilayer film, for example, a vacuum film formation process such as a CVD method, a sputtering method, a vacuum deposition method, or the like; wet film forming processes such as spraying and dipping.

The predetermined optical characteristics may be provided by one reflective layer (a set of dielectric multilayer films), or may be provided by two or more reflective layers. In the case of having two or more reflective layers, the reflective layers may have the same or different configurations. When two or more reflective layers are provided, the reflective layer is generally composed of a plurality of reflective layers having different reflection bands.

For example, when two reflective layers are provided, one reflective layer may be a near infrared reflective layer that blocks light in a short wavelength range in the near infrared region, and the other reflective layer may be a near infrared/near ultraviolet reflective layer that blocks light in two wavelength ranges, i.e., a long wavelength range and a near ultraviolet range, in the near infrared region. For example, in the case where the optical filter has a transparent substrate, when two or more reflective layers are provided, all of the reflective layers may be provided on one main surface of the transparent substrate, or each reflective layer may be provided on both main surfaces of the transparent substrate so as to sandwich the transparent substrate.

(antireflection layer)

The antireflection layer may be a dielectric multilayer film, an intermediate refractive index medium, a moth-eye structure in which the refractive index gradually changes, or the like. Among them, a dielectric multilayer film is preferable from the viewpoint of optical efficiency and productivity. The antireflection layer is obtained by alternately laminating dielectric films as with the reflection layer.

The filter may include, as other components, components (layers) for imparting absorption by inorganic fine particles or the like for controlling transmission and absorption of light in a specific wavelength range. Specific examples of the inorganic fine particles include ITO (indium tin oxide), ATO (antimony doped tin oxide), cesium tungstate, lanthanum boride, and the like. ITO fine particles and cesium tungstate fine particles have high visible light transmittance and have light absorption in a wide range of an infrared wavelength range of more than 1200nm, and therefore can be used in a case where such infrared light blocking property is required.

In the present filter, by having the reflective layer and the absorption layer containing the dye (a), it is possible to suppress the incident angle dependence on light incident at a high angle, and in particular, it is possible to reduce light leakage in the wavelength range of 800nm to 900nm at a high incident angle, and the transmittance of visible light is high.

When the absorbing layer contains the dye (A), the filter satisfies the above (ii-1). When the absorbing layer further contains a dye (D), the optical filter satisfies the optical characteristics (ii-2) to (ii-6) described above.

The optical filter can provide an imaging device excellent in color reproducibility when used in an imaging device such as a digital camera. An imaging device using the present filter has a solid-state imaging element, an imaging lens, and the present filter. The present filter can be used, for example, as follows: disposed between the imaging lens and the solid-state imaging element, or directly pasted on the solid-state imaging element, the imaging lens, and the like of the imaging device via an adhesive layer.