阅读说明：本技术 近红外线吸收色素和吸收层 (Near-infrared absorbing dye and absorbing layer ) 是由 盐野和彦 松浦启吾 东田盛纱友梨 保高弘树 于 2016-05-11 设计创作，主要内容包括：一种光学滤波器,具备在具有良好的近红外线屏蔽特性的同时提高可见光透射率、并且与抵接的层的密合性优异、进而耐光性优异的吸收层。所述光学滤波器具备吸收层和与吸收层相接的无机或者有机材料,该吸收层含有包含方酸<Image he="67" wi="69" file="DDA0002550304290000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>系色素的近红外线吸收色素和透明树脂。方酸<Image he="77" wi="75" file="DDA0002550304290000013.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>系色素在方酸<Image he="66" wi="71" file="DDA0002550304290000012.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>骨架的两侧键合包含苯环和作为环的构成原子的氮原子的稠环结构,在苯环的2位具有氨基甲酸酯结构。(An optical filter having an absorption layer which has excellent near-infrared ray shielding properties, improved visible light transmittance, excellent adhesion to a layer to be brought into contact therewith, and further excellent light resistance. The optical filter comprises an absorbing layer containing a squaric acid and an inorganic or organic material in contact with the absorbing layer A near-infrared absorbing dye containing a dye and a transparent resin. Squaric acid Is a pigment in a squaric acid A condensed ring structure including a benzene ring and a nitrogen atom as a ring constituent atom is bonded to both sides of the skeleton, and the 2-position of the benzene ring has a urethane structure.)

1. A near-infrared absorbing dye characterized by comprising a formula (AI) tableCubic acid of

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

x is independently a 2-valent organic group represented by formula (1) or formula (2) in which 1 or more hydrogen atoms may be substituted by an alkyl group or alkoxy group having 1 to 12 carbon atoms,

－(CH₂)_n1－ …(1)

in the formula (1), n1 is 2 or 3,

－(CH₂)_n2－O－(CH₂)_n3－ …(2)

in the formula (2), n2 and n3 are each independently an integer of 0 to 2, n2+ n3 is 1 or 2,

R¹independently represents a saturated or unsaturated hydrocarbon group having 1 to 12 carbon atoms, a saturated cyclic hydrocarbon group having 3 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms or an alkylaryl group having 7 to 13 carbon atoms, which may have a saturated ring structure and may have a branched chain,

R²independently a hydrocarbon group of 1 to 25 carbon atoms in which 1 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 an unsaturated bond, an oxygen atom, a saturated or unsaturated ring structure may be contained between carbon atoms,

R³and R⁴Independently represents a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 10 carbon atoms.

2. The near-infrared absorbing dye according to claim 1, wherein in the formula (AI), X is a 2-valent organic group represented by the formula (3),

－CR⁵ ₂－(CR⁶ ₂)_n4－ …(3)

wherein, the formula (3) represents a 2-valent group with the left side bonded with a benzene ring and the right side bonded with N,

n4 is 1 or 2 and,

R⁵each independently an alkyl group or alkoxy group having 1 to 12 carbon atoms which may have a branch,

R⁶each independently represents a hydrogen atom or an alkyl group or alkoxy group having 1 to 12 carbon atoms which may have a branch.

3. The near-infrared absorbing dye according to claim 2, wherein in the formula (3), R is⁵Each independently an alkyl or alkoxy group having 1 to 6 carbon atoms which may have a branch, R⁶Each independently represents a hydrogen atom or an alkyl group or alkoxy group having 1 to 6 carbon atoms which may have a branch.

4. The near-infrared absorbing dye according to claim 1, wherein in the formula (AI), X is any one of 2-valent organic groups represented by the formulae (11-1) to (12-4),

－C(CH₃)₂－CH(CH₃)－ …(11－1)

－C(CH₃)₂－CH₂－ …(11－2)

－C(CH₃)₂－CH(C₂H₅)－ …(11－3)

－C(CH₃)₂－CH₂－CH₂－ …(12－1)

－C(CH₃)₂－CH₂－CH(CH₃)－ …(12－2)

－C(CH₃)₂－CH(CH₃)－CH₂－ …(12－3)

－C(CH₃)₂－CH(C₃H₇) …(12－4)

wherein, the groups represented by the formulas (11-1) to (12-4) are all bonded with a benzene ring at the left side and N at the right side.

5. According to claims 1 to E4, wherein R in the formula (AI) is¹Independently a group represented by the formula (4-1) or the formula (4-2),

in the formulae (4-1) and (4-2), R⁷、R⁸、R⁹、R¹⁰And R¹¹Independently represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms.

6. The near-infrared absorbing dye according to any one of claims 1 to 4, wherein in the formula (AI), R is²Independently an alkyl group or an alkoxy group having 1 to 12 carbon atoms, which may have a branch.

7. The near-infrared absorbing dye according to any one of claims 1 to 4, wherein the squaric acid represented by the formula (AI)

(i-1) an absorption spectrum having a wavelength of 400 to 800nm and a maximum absorption wavelength λ of 670 to 730nm_max，

(i-2) maximum absorptivity of light having a wavelength of 430 to 550nm_AMaximum absorption coefficient with light with wavelength of 690-730 nm_BIn which the following relation holds,

_B/_A≥50

(i-3) spectral transmittance curve in which the maximum absorption wavelength λ is set_maxA wavelength λ at which the transmittance on the short wavelength side of the maximum absorption wavelength is 80% when the transmittance is 10%₈₀And the maximum absorption wavelength lambda_maxThe difference is 60nm or less.

8. An absorbent layer, comprising:

the near-infrared absorbing coloring matter according to any one of claims 1 to 4, and

and a transparent resin containing at least 1 selected from the group consisting of acrylic resins, epoxy resins, ene-thiol resins, polycarbonate resins, polyether resins, polyarylate resins, polysulfone resins, polyethersulfone resins, polyparaphenylene resins, polyarylene ether phosphine oxide resins, polyimide resins, polyamideimide resins, polyolefin resins, cyclic olefin resins, and polyester resins.

9. The absorbent layer according to claim 8, comprising a silane coupling agent having at least 1 selected from the group consisting of a vinyl group, an epoxy group, a styrene group, a methacrylic group, an acrylic group, an amino group, a urea group, a mercapto group, a thioether group, and an isocyanate group.

10. The absorption layer according to claim 8 or 9, wherein an ultraviolet absorbing pigment satisfying (ii-1) is contained,

(ii-1) has a maximum absorption wavelength in a wavelength region of 360 to 415nm in an absorption spectrum of 350 to 800nm measured by dissolving in methylene chloride.

11. The absorption layer according to claim 10, wherein the ultraviolet absorbing coloring matter is a compound represented by formula (M),

the symbols in the formula (M) are as follows,

y represents Q⁶And Q⁷Substituted methylene or oxygen atoms, here, Q⁶And Q⁷Each independently represents a hydrogen atom, a halogen atom or an alkyl or alkoxy group having 1 to 10 carbon atoms,

Q¹represents a C1-12 hydrocarbon group which may have a substituent,

Q²～Q⁵each independently represents a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 10 carbon atoms,

z represents a 2-valent group represented by any one of the formulae (Z1) to (Z5),

wherein Q is⁸And Q⁹Each independently is a C1-12 hydrocarbon group which may have a substituent, Q¹⁰～Q¹⁹Each independently represents a hydrogen atom or a substituted or unsubstituted 1-valent hydrocarbon group having 1 to 12 carbon atoms.

Technical Field

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

Background

An imaging device using a solid-state imaging element such as a CCD mounted in a digital camera or the like has been used with an optical filter (near infrared ray cut filter) that transmits visible light and shields near infrared light in order to obtain a clear image while reproducing a color tone well.

In particular, an optical filter using a dye having high absorption in the near infrared region and high transmittance in the visible light region is widely used because steep shielding properties against near infrared rays and good color reproducibility of visible light images can be obtained.

Such a near-infrared cut filter uses a resin layer (resin substrate) in which a dye having a light absorption function is dissolved or dispersed in a transparent resin. In addition, for the purpose of enhancing strength, the near-infrared cut filter is formed by laminating such a resin layer on a transparent substrate made of an inorganic material such as glass, or by providing an antireflection layer made of an inorganic multilayer film on the surface. In this case, if the adhesion between the resin layer and the transparent substrate or between the resin layer and the inorganic multilayer film is low, various problems may occur due to peeling. Therefore, the resin layer is required to have high adhesion to a transparent substrate such as a glass substrate or an inorganic multilayer film.

In addition, even if both high near-infrared light shielding properties and high visible light transmittance are desired, the near-infrared cut filter does not exhibit 100% transmittance over the entire visible light region, and may have a region with relatively low transmittance even in the visible light region.

For example, squaric acidThe dye has excellent near-infrared light shielding properties, and also has a transmittance of visible light of a certain level or more, and the transmittance of light in the visible light region changes rapidly to the near-infrared region. For example, the applicant previously filed a patent application containing a squaric acid having an amide groupAn optical filter containing a dye (patent document 1) obtains sufficient color reproducibility to some extent by utilizing the spectral transmittance characteristics of the optical filter. However, the squaric acid having an amide groupThe dye also exhibits some absorption in the visible light region. In particular, the transmittance of light having a wavelength of 430 to 550nm is low compared with the transmittance of light in other visible light regions, and particularly, the accuracy of color reproducibility in imaging of the blue system is a practical level, but it may be somewhat insufficient. Further, the squaric acid having an amide group is containedThe adhesion of the pigment-based resin layer (absorbing layer) to an inorganic material such as glass is also at least a certain level, but furtherA higher level of adhesion is required.

Among them, various kinds of squaric acids having novel structures have been proposed for improving the transmittance of visible lightA pigment, but the level has not yet reached a satisfactory level (patent documents 2 and 3). In addition, it is also proposed to use squaric acidAn optical filter in which a phthalocyanine-based dye is used in combination with a dye to improve shielding properties particularly in the near ultraviolet region (patent document 4). However, patent document 4 does not disclose a technique for improving the transmittance of light having a wavelength of 430 to 550nm, in particular, as the transmittance of visible light. In addition, since a plurality of different pigments are used, there is a possibility that the absorption of visible light is increased by some factor. Further, no technique has been reported which considers the adhesion between a resin layer containing a coloring matter and an inorganic material such as glass. Further, the light durability (light resistance) is not particularly described.

Disclosure of Invention

The purpose of the present invention is to provide an optical filter having an absorbing layer that has good near-infrared ray shielding properties, has improved visible light transmittance, and has excellent adhesion to a substrate, an inorganic multilayer film, and the like, and excellent light resistance, and to provide a highly reliable imaging device using the optical filter.

An optical filter according to one aspect of the present invention includes an absorption layer containing a near-infrared absorbing dye and a transparent resin, and an inorganic or organic material in contact with the absorption layer, wherein the absorption layer is formed of a material containing a near-infrared absorbing dye and a transparent resinThe near infrared ray absorbing dye contains squaric acid represented by formula (AI)

Is a pigment.

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

X is independently a 2-valent organic group represented by formula (1) or formula (2) in which 1 or more hydrogen atoms may be substituted by an alkyl group or alkoxy group having 1 to 12 carbon atoms.

－(CH₂)_n1－…(1)

In the formula (1), n1 is 2 or 3.

－(CH₂)_n2－O－(CH₂)_n3－…(2)

In the formula (2), n2 and n3 are each independently an integer of 0 to 2, and n2+ n3 is 1 or 2.

R¹Independently represents a saturated or unsaturated hydrocarbon group having 1 to 12 carbon atoms, which may have a saturated ring structure, which may have a branched chain, a saturated cyclic hydrocarbon group having 3 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkylaryl group having 7 to 13 carbon atoms.

R²Independently 1 or more hydrogen atoms may be substituted by a halogen atom, a hydroxyl group, a carboxyl group, a sulfo group or a cyano group, and a hydrocarbon group having 1 to 25 carbon atoms which may have an unsaturated bond, an oxygen atom, a saturated or unsaturated ring structure between carbon atoms.

R³And R⁴Independently represents a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 10 carbon atoms.

In addition, an imaging device according to another aspect of the present invention includes the optical filter.

According to the present invention, an optical filter having an absorption layer having excellent near-infrared ray shielding properties, improved visible light transmittance, excellent adhesion to a base material, an inorganic multilayer film, or the like, and excellent light resistance is obtained. Further, an imaging device using such an optical filter and having high reliability is obtained.

Drawings

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

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

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

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

Fig. 2 is a graph showing a spectral transmittance curve of the selective wavelength shielding layer used in the optical filter of the example.

Detailed Description

Hereinafter, embodiments of the present invention will be described. In the following description, the optical filter is abbreviated as "NIR filter", the near-infrared absorbing dye is abbreviated as "NIR absorbing dye" or "NIR dye", and the ultraviolet absorbing dye is abbreviated as "UV absorbing dye" or "UV dye".

< NIR Filter >

An NIR filter according to an embodiment of the present invention (hereinafter referred to as the present filter) includes a1 st layer and a2 nd layer that is adjacent to the 1 st layer and is different from the 1 st layer.

The 1 st layer is an absorption layer containing a near-infrared absorbing dye (A) and a transparent resin (B). The 2 nd layer is a layer made of an inorganic or organic material, and is, for example, a transparent base material including a glass substrate, a transparent resin substrate, or the like, a selective wavelength shielding layer made of a dielectric multilayer film for shielding light in a specific wavelength region, an antireflection layer made of a dielectric multilayer film for suppressing a transmittance loss in a visible light region, or the like.

Each of the 1 st layer and the 2 nd layer may have 1 layer or 2 or more layers in the present filter. When the number of layers is 2 or more, the layers may have the same or different structures. The 1 st layer itself may function as a substrate (resin substrate).

The filter may have layers other than the 1 st and 2 nd layers, i.e., the 3 rd layer not contiguous with the 1 st layer. The transparent substrate such as the glass substrate or the resin substrate may include a selective wavelength shielding layer formed of a dielectric multilayer film for shielding light in a specific wavelength region, and an antireflection layer formed of a dielectric multilayer film for suppressing a transmittance loss of visible light as the 3 rd layer.

Hereinafter, a representative configuration example of the present filter will be described with reference to the drawings.

Fig. 1A shows an example of a configuration in which selective wavelength shielding layers 12 made of a dielectric multilayer film are provided as 2 nd layers on both main surfaces of an absorption layer (1 st layer) 11.

Fig. 1B shows an example of a configuration in which a selective wavelength shielding layer 12 made of a dielectric multilayer film and an antireflection layer 13 made of a dielectric multilayer film are provided as the 2 nd layer on both main surfaces of an absorption layer (1 st layer) 11.

Fig. 1C shows an example of a configuration in which a transparent substrate 14 and a selective wavelength shielding layer 12 made of a dielectric multilayer film are provided as the 2 nd layer on each of the principal surfaces of an absorption layer (1 st layer) 11. In this example, an antireflection layer 13 made of a dielectric multilayer film is further provided as the 3 rd layer on the main surface of the transparent substrate 14 on the side opposite to the absorption layer (1 st layer) 11.

Fig. 1D shows an example of a configuration in which a transparent substrate 14 and an antireflection layer 13 made of a dielectric multilayer film are provided as the 2 nd layer on each of the principal surfaces of an absorption layer (1 st layer) 11. In this example, the selective wavelength shielding layer 12 composed of a dielectric multilayer film is further provided as the 3 rd layer on the principal surface of the transparent substrate 14 on the side opposite to the side of the absorption layer (1 st layer) 11.

In fig. 1A and 1B, the 2 selective wavelength shielding layers 12 may be the same or different. For example, one selective wavelength shielding layer may reflect ultraviolet light and light in the 1 st near infrared region, and the other selective wavelength shielding layer 12 may reflect ultraviolet light and light in the 2 nd near infrared region different from the 1 st near infrared region.

The filter preferably has a spectral transmittance characteristic satisfying (iv-1), more preferably at least one of (iv-1) and (iv-2) to (iv-6). It is particularly preferable that all of (iv-1) to (iv-6) are satisfied.

(iv-1) the spectral transmittance curve at an incident angle of 0 DEG, wherein the average transmittance of light having a wavelength of 430 to 550nm is 90% or more, and the minimum transmittance of light having a wavelength of 430 to 550nm is 75% or more.

(iv-2) an average transmittance of light having a wavelength of 600 to 700nm in a spectral transmittance curve at an incident angle of 0 DEG of 25% or more.

(iv-3) an average transmittance of light having a wavelength of 350 to 395nm of 2% or less in a spectral transmittance curve at an incident angle of 0 °.

(iv-4) an average transmittance of light having a wavelength of 710 to 1100nm in a spectral transmittance curve at an incident angle of 0 DEG of 2% or less.

(iv-5) the average value of the absolute values of the differences between the transmittances of light with wavelengths of 385 to 430nm in the spectral transmittance curve at an incident angle of 0 DEG and the transmittances of light with wavelengths of 385 to 430nm in the spectral transmittance curve at an incident angle of 30 deg (hereinafter referred to as "the transmittance average shift amount of 385 to 430 nm") is 7%/nm or less.

(iv-6) the average value of the absolute values of the differences between the transmittances of light having wavelengths of 600 to 700nm in the spectral transmittance curve at an incident angle of 0 DEG and the transmittances of light having wavelengths of 600 to 700nm in the spectral transmittance curve at an incident angle of 30 DEG (hereinafter referred to as "the transmittance average shift amount at a wavelength of 600 to 700 nm") is 7%/nm or less.

By satisfying (iv-1), the transmittance of light having a wavelength of 430 to 550nm can be improved, and the accuracy of color reproducibility in imaging of a blue system can be further improved.

By satisfying the requirement (iv-2), light having a wavelength of 700nm or more, which is unnecessary for the solid-state imaging element, can be shielded, and the transmittance of light having a wavelength of 600 to 700nm, which is responsible for human visual sensitivity, can be maintained relatively high.

By satisfying (iv-3), light in a wavelength region of 395nm or less can be shielded, and the spectral sensitivity of the solid-state imaging element can be brought close to the human visual sensitivity.

By satisfying the requirement (iv-4), light having a wavelength of 710 to 1100nm can be shielded, and the spectral sensitivity of the solid-state imaging device can be brought close to the human visual sensitivity.

By satisfying (iv-5), the incident angle dependence of light having a wavelength of 385 to 430nm can be reduced. As a result, the incident angle dependency of the spectral sensitivity of the solid-state imaging element in the wavelength region can be reduced.

By satisfying (iv-6), the incident angle dependence of light having a wavelength of 600 to 700nm can be reduced. As a result, the incident angle dependency of the spectral sensitivity of the solid-state imaging element in the wavelength region can be reduced.

The average transmittance of the filter for light having a wavelength of 430 to 550nm in a spectral transmittance curve at an incident angle of 0 DEG is more preferably 91% or more, and still more preferably 92% or more. The higher the average transmittance of the optical filter for light having a wavelength of 430 to 550nm, the more visible light can be obtained.

The minimum transmittance of the filter for light having a wavelength of 430 to 550nm in a spectral transmittance curve at an incident angle of 0 DEG is more preferably 77% or more, and still more preferably 80% or more. The higher the minimum transmittance of light with a wavelength of 430-550 nm of the optical filter is, the more visible light can be obtained.

The average transmittance of the filter is more preferably 30% or more for light having a wavelength of 600 to 700nm in a spectral transmittance curve at an incident angle of 0 deg. The higher the average transmittance of light having a wavelength of 600 to 700nm of the optical filter is, the more shielding light having a wavelength of 700nm or more which is unnecessary for visual sensitivity can be achieved, and the transmittance of light having a wavelength of 600 to 700nm which participates in human visual sensitivity can be maintained higher.

In addition, the average transmittance of the filter in a spectral transmittance curve at an incident angle of 0 DEG for light having a wavelength of 430 to 480nm is preferably 87% or more, more preferably 88% or more, still more preferably 89% or more, and still more preferably 90% or more. The higher the average transmittance of the optical filter for light having a wavelength of 430 to 480nm, the higher the accuracy of color reproducibility of the blue system.

The average transmittance of the filter for light having a wavelength of 350 to 395nm in a spectral transmittance curve at an incident angle of 0 DEG is more preferably 1.5% or less, still more preferably 1% or less, and still more preferably 0.5% or less. The lower the average transmittance of the optical filter for light having a wavelength of 350 to 395nm, the more light having a wavelength unnecessary for the solid-state imaging device can be shielded.

The average transmittance of the filter for light having a wavelength of 710 to 1100nm in a spectral transmittance curve at an incident angle of 0 DEG is more preferably 1% or less, still more preferably 0.5% or less, and still more preferably 0.3% or less. The lower the average transmittance of the optical filter for light having a wavelength of 710 to 1100nm, the more light having a wavelength unnecessary for the solid-state imaging element can be shielded.

The average displacement of the transmittance of the filter at wavelengths 385 to 430nm is more preferably 6%/nm or less, and still more preferably 5%/nm or less. The average displacement of the transmittance at wavelengths 385 to 430nm is an index showing the incident angle dependence of the filter at wavelengths 385 to 430 nm. The smaller the value, the lower the incident angle dependency.

The average displacement of transmittance of the filter at a wavelength of 600 to 700nm is more preferably 3%/nm or less, and still more preferably 2%/nm or less. The average displacement of transmittance at a wavelength of 600 to 700nm is an index showing the dependence of the incident angle of light of the filter at a wavelength of 600 to 700 nm. The smaller the value, the lower the incident angle dependency.

Next, the absorption layer, selective wavelength shielding layer, antireflection layer, and transparent substrate constituting the filter will be described.

[ absorbing layer ]

The absorption layer is a layer containing the near-infrared absorbing dye (a) and the transparent resin (B), and typically is a layer or a (resin) substrate in which the near-infrared absorbing dye (a) is uniformly dissolved or dispersed in the transparent resin (B). The absorbing layer may further contain an ultraviolet absorbing dye (U).

In the present filter, a plurality of absorption layers may be provided as described above.

(near-infrared absorbing dye (A))

The near-infrared absorbing dye (a) (hereinafter, also referred to as NIR dye (a)) contained in the absorbing layer of the filter includes at least 1 type selected from NIR dyes represented by formula (AI).

In the present specification, the NIR dye represented by formula (AI) is also referred to as NIR dye (AI). The same applies to other pigments. As described later, for example, the group represented by formula (1n) is referred to as group (1 n). Groups represented by other formulae are also shown.

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

X is independently a 2-valent organic group represented by formula (1) or formula (2) in which 1 or more hydrogen atoms may be substituted by an alkyl group or alkoxy group having 1 to 12 carbon atoms.

－(CH₂)_n1－…(1)

In the formula (1), n1 is 2 or 3.

－(CH₂)_n2－O－(CH₂)_n3－…(2)

In the formula (2), n2 and n3 are each independently an integer of 0 to 2, and n2+ n3 is 1 or 2.

R¹Independently represents a saturated or unsaturated hydrocarbon group having 1 to 12 carbon atoms, which may have a saturated ring structure, which may have a branched chain, a saturated cyclic hydrocarbon group having 3 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkylaryl group having 7 to 13 carbon atoms.

R²Independently 1 or more hydrogen atoms may be substituted by a halogen atom, a hydroxyl group, a carboxyl group, a sulfo group or a cyano group, and a hydrocarbon group having 1 to 25 carbon atoms which may have an unsaturated bond, an oxygen atom, a saturated or unsaturated ring structure between carbon atoms.

R³And R⁴Independently represents a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 10 carbon atoms.

In the present specification, the saturated or unsaturated ring structure refers to a hydrocarbon ring and a heterocyclic ring having an oxygen atom as a ring-constituting atom. Also included in this category are structures in which an alkyl group having 1 to 10 carbon atoms is bonded to a carbon atom constituting a ring.

The aryl group is 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. The alkylaryl group is a linear or branched saturated or unsaturated hydrocarbon group or a saturated cyclic hydrocarbon group which is substituted with 1 or more aryl groups and may have a saturated ring structure.

The NIR pigments (AI) have a squaric acid in the center of the molecular structure

Skeleton in squaric acidThe skeleton has 1 benzene ring bonded to each of the left and right sides of the skeleton, the benzene ring being bonded to the nitrogen atom at the 4-position, and the left and right sides of the skeleton having a condensed ring structure in which a heterocyclic ring including the nitrogen atom, the carbon atoms at the 4-position and the 5-position of the benzene ring is formed. The NIR dye (AI) is bonded to the carbamate group represented by formula (a1) at each of the 2-positions of the 1 benzene rings on the left and right sides.

In the NIR dye (AI), the ring structures constituting rings other than benzene rings present in 1 fused ring structures on the left and right sides are determined by the above X, and each independently represents a heterocyclic ring having 5 or 6 members. The 2-valent group X constituting a part of the heterocyclic ring may have a skeleton composed of only carbon atoms as represented by formula (1), or may have an oxygen atom in addition to carbon atoms as represented by formula (2). In the formula (2), the position of the oxygen atom is not particularly limited. That is, the nitrogen atom may be bonded to the oxygen atom, or the oxygen atom may be directly bonded to the benzene ring. Further, the oxygen atom may be located at a position sandwiched by carbon atoms.

The left and right X's may be the same or different, but are preferably the same from the viewpoint of productivity. In addition, for R¹～R⁴Also clamp the squaraine in the same way

The framework can be the same or different from side to side,from the viewpoint of productivity, the same is preferable.

As described above, NIR dye (AI) is bonded to squaric acidThe compound has a structure in which a carbamate group is bonded to the 2-position of the left and right benzene rings of the skeleton, and thus has a structure in which a conventional squaric acid is bonded to the compound

The NIR dye (AI) is a dye having spectral transmittance characteristics in the near infrared region and the visible light region equal to or greater than those of the above-mentioned series dyes, and as a layer in contact with the absorbing layer containing the NIR dye (AI), not only adhesion to a layer made of an organic material but also adhesion to a layer made of an inorganic material such as glass or a dielectric multilayer film can be improved. This is considered to be because the polarity of the NIR dye itself is increased by containing a urethane group, and the chemical interaction of the NIR dye with an inorganic material such as glass is increased.

In addition, since the NIR dye (AI) has a urethane group, the light resistance of the absorbing layer is improved, and thus the optical filter can be provided with good light resistance. The light resistance of the optical filter can be evaluated by, for example, irradiating the optical filter with light for a certain period of time and evaluating the variation of the maximum transmittance in a predetermined wavelength range before and after the irradiation, and the smaller the variation of the maximum transmittance, the better the light resistance.

An irradiation device: xenon lamp (wavelength 300 ~ 2450nm)

Temperature: 40 deg.C

Humidity: 50% RT

Cumulative light quantity: 87.2 kw.h/m²

Further, the NIR dye (AI) has good solubility in an organic solvent, and thus has good compatibility with a transparent resin. As a result, the optical filter has excellent spectral characteristics even when the thickness of the absorbing layer is reduced, and can be made smaller and thinner. In addition, since the NIR dye (AI) can reduce the thickness of the absorbing layer, thermal expansion of the absorbing layer due to heating can be suppressed, and the occurrence of cracks and the like in these layers when the selective wavelength shielding layer and other functional layers such as an antireflection layer are formed can be suppressed.

The substituent R is a substituent R from the viewpoint of solubility in an organic solvent and compatibility with a transparent resin¹A group having a branched structure is preferable, and an alkyl group or an alkoxy group having a branched structure is more preferable.

X of the NIR dye (AI) is preferably a 2-valent organic radical of the formula (3).

－CR⁵ ₂－(CR⁶ ₂)_n4－…(3)

Wherein, formula (3) represents a 2-valent group having the left side bonded to a benzene ring and the right side bonded to N, and N4 is 1 or 2. n4 is preferably 1. In addition, R⁵Each independently is an alkyl group or alkoxy group having 1 to 12 carbon atoms, which may have a branch, preferably an alkyl group or alkoxy group having 1 to 6 carbon atoms, which may have a branch. And, R⁶Each independently represents a hydrogen atom or an alkyl or alkoxy group having 1 to 12 carbon atoms which may have a branch, preferably a hydrogen atom or an alkyl or alkoxy group having 1 to 6 carbon atoms which may have a branch.

X in the formula (AI) is particularly preferably any of the 2-valent organic groups represented by the formulae (11-1) to (12-3). Wherein, the formulas (11-1) to (12-3) all represent 2-valent groups in which the left side is bonded to a benzene ring and the right side is bonded to N.

－C(CH₃)₂－CH(CH₃)－…(11－1)

－C(CH₃)₂－CH₂－…(11－2)

－C(CH₃)₂－CH(C₂H₅)－…(11－3)

－C(CH₃)₂－CH₂－CH₂－…(12－1)

－C(CH₃)₂－CH₂－CH(CH₃)－…(12－2)

－C(CH₃)₂－CH(CH₃)－CH₂－…(12－3)

Among these, X in the formula (AI) is preferably any of the groups (11-1) to (11-3), and more preferably the group (11-1).

Hereinafter, the structural formula of the NIR dye (Ai) in which both the left and right X are the group (11-1) is shown. In the NIR dye (Ai), R¹～R⁴Is related to R in NIR pigment (AI)¹～R⁴The same meaning is used.

In the NIR dye (AI), R is a group having a sharp change in the spectral transmittance curve in the vicinity of the boundary between the visible region and the near-infrared region, and from the viewpoints of solubility, heat resistance, and the like¹Independently, a group represented by the formula (4-1) or the formula (4-2) is more preferable.

In the formulae (4-1) and (4-2), R⁷、R⁸、R⁹、R¹⁰And R¹¹Independently represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms.

In addition, in NIR dye (AI), R³And R⁴Independently, a hydrogen atom, a halogen atom, or an alkyl group or alkoxy group having 1 to 6 carbon atoms is preferable. R³And R⁴Hydrogen atoms are more preferred.

The NIR dye (AI) is preferably an NIR dye (AI), and among them, the NIR dyes (A1-1) to (A1-13) having the configurations shown in Table 1 are more preferably used. In addition, especially preferred are NIR dyes (A1-2) to (A1-4), (A1-6) to (A1-8), and (A1-10) to (A1-13) from the viewpoint of solubility of the dye. Incidentally, the NIR dyes (A1-1) to (A1-13) are present in a total of 2R's each of 1 on the left and right sides¹Is the same on the left and right, R²～R⁴The same applies.

[ Table 1]

The NIR dye (AI) can be produced, for example, by the method described in international publication No. 14/088063. Specifically, the NIR dye (AI) can be produced by reacting 3, 4-dihydroxy-3-cyclobutene-1, 2-dione (squaric acid) with a compound having a condensed ring which can be bonded to the squaric acid to form a structure represented by formula (AI). For example, when the NIR dye (AI) has a bilaterally symmetric structure, 2 equivalents of the compound having a condensed ring having a desired structure in the above range may be reacted with 1 equivalent of squaric acid.

The reaction route in obtaining an NIR dye (Ai) is shown below as a specific example. The squaric acid in the reaction formula (F1) is represented by(s). According to the reaction formula (F1), the indole skeleton has a desired substituent (R)¹、R³、R⁴) Introducing an amino group (f) into the benzene ring of the compound (d) to further have a desired substituent R²Chloroformate (g) to obtain carbamate compound (h). The carbamate compound (h)2 equivalents and the squaric acid(s) 1 equivalent are reacted to obtain the NIR dye (Ai).

In the reaction formula (F1), R¹～R⁴Is a group represented by the formula (Ai)¹～R⁴In the same sense, Me represents methyl and THF represents tetrahydrofuran. Hereinafter, in the present specification, Me and THF are used as defined above.

In the present embodiment, the absorption characteristics measured by dissolving the NIR dye (AI) in methylene chloride preferably satisfy (i-1) to (i-3).

(i-1) an absorption spectrum having a wavelength of 400 to 800nm, and having a maximum absorption wavelength λ in a wavelength region of 670 to 730nm, preferably 680 to 720nm, more preferably 690 to 710nm_max。

(i-2) maximum absorptivity of light having a wavelength of 430 to 550nm_AThe maximum absorption coefficient of the light with the wavelength of 670-730 nm_BThe following relational expression holds.

_B/_A≥50

The relation is preferably_B/_AMore preferably 60 or more_B/_A≥70。

(i-3) spectral transmittance curve, the maximum absorption wavelength λ_maxAt the maximum absorption wavelength λ when the transmittance is 10%_maxWavelength λ having a transmittance of 80% on the short wavelength side₈₀With the above-mentioned maximum absorption wavelength lambda_maxDifference of difference lambda_max－λ₈₀Is 60nm or less. Lambda [ alpha ]_max－λ₈₀Preferably 55nm or less, more preferably 50nm or less.

By using the NIR dye (A) satisfying (i-1) to (i-3), a highly reliable optical filter having excellent near infrared ray shielding properties and excellent adhesion to the contact layer is obtained.

Specifically, near-infrared light can be sufficiently shielded by satisfying (i-1). Further, satisfying (i-2) enables sufficient transmission of visible light. Further, satisfying (i-3) makes it possible to make the change in the spectral transmittance curve in the vicinity of the boundary between the visible light region and the near infrared region (transmittance transition region) rapid.

In the present embodiment, the NIR dye (a) may contain a dye other than the NIR dye (AI) as necessary within a range not to inhibit the effects of the present invention. From the viewpoint of adhesion, it is preferable to use only NIR dye (AI).

The content of the NIR dye (a) in the absorbing layer is preferably 0.1 to 30 parts by mass with respect to 100 parts by mass of the transparent resin (B). By setting the amount to 0.1 part by mass or more, a desired near infrared ray absorption ability can be obtained, and by setting the amount to 30 parts by mass or less, a decrease in near infrared ray absorption ability, an increase in haze value, and the like can be suppressed. The content of the NIR dye (a) is more preferably 0.5 to 25 parts by mass, and still more preferably 1 to 20 parts by mass.

(ultraviolet absorbing dye (U))

The absorption layer may contain a UV pigment (U) in addition to the NIR pigment (a) and the transparent resin. The UV dye (U) (hereinafter also referred to as "dye (U)") preferably satisfies (ii-1).

(ii-1) has a maximum absorption wavelength in a wavelength region of 360 to 415nm in an absorption spectrum of 350 to 800nm measured by dissolving in methylene chloride (hereinafter referred to as "absorption spectrum of UV dye (U)").

When the UV dye (U) satisfying (ii-1) is used, the maximum absorption wavelength is appropriate and the absorption spectrum has a steep rise, so that a good ultraviolet shielding property can be obtained without lowering the transmittance after 430 nm.

In the absorption spectrum of the UV dye (U), the maximum absorption wavelength of the UV dye (U) is more preferably in the wavelength region of 370 to 415nm, and still more preferably in the wavelength region of 390 to 410 nm.

Specific examples of the UV dye satisfying (ii-1) (hereinafter referred to as UV dye (U1)) suitable for the present embodiment include

Azole series, merocyanine series, cyanine series, naphthalimide series,A diazole series,An oxazine series,Dyes such as oxazolidine, naphthalenedicarboxylic acid, styrene, anthracene, cyclic carbonyl, and triazole.

As the UV dye (U1), a UV dye (N)) represented by the formula (N) can be mentioned.

In the formula (N), R¹²Each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may contain a saturated or unsaturated ring structure and may have a branch. Specific examples thereof include a linear or branched alkyl group, an alkenyl group, a saturated cyclic hydrocarbon group, an aryl group, and an alkylaryl group.

In addition, the formula (A)In N), R¹³Each independently is a cyano group or a group represented by formula (n).

－COOR³⁰…(n)

In the formula (n), R³⁰The alkyl group may contain a saturated or unsaturated ring structure, and may have a branched carbon number of 1 to 20. Specific examples thereof include a linear or branched alkyl group, an alkenyl group, a saturated cyclic hydrocarbon group, an aryl group, and an alkylaryl group.

As R in UV pigment (N)¹²Particularly preferred are groups represented by the formulae (1n) to (4 n). In addition, as R in the UV dye (N)¹³The group represented by the formula (5n) is particularly preferable.

Examples of the UV dye (N) include UV dyes (N-1) to (N-4) having the configurations shown in Table 2. Note that R in Table 2¹²And R¹³The specific structure of (3) corresponds to formulae (1n) to (5 n). Table 2 also shows the corresponding pigment abbreviations. In the UV dyes (N-1) to (N-4), 2R's are present¹²Same as R¹³The same applies.

[ Table 2]

Pigment abbreviations	R12	R13
			N-1	1n	5n
N-2	2n	5n
			N-3	3n	5n
N-4	4n	5n

Among the UV dyes (U1) exemplified above, preferred isExamples of commercially available azole-based and merocyanine-based dyes include Uvitex (registered trademark) OB and Hakkol (registered trademark) RF-K, S0511.

(merocyanine-based dye)

The UV dye (U1) is particularly preferably a merocyanine dye represented by the formula (M).

In the formula (M), Y represents Q⁶And Q⁷Substituted methylene or oxygen atoms. Here, Q⁶And Q⁷Each independently represents a hydrogen atom, a halogen atom, or an alkyl group or alkoxy group having 1 to 10 carbon atoms. Q⁶And Q⁷Each independently of the other, is preferably a hydrogen atom or an alkyl or alkoxy group having 1 to 10 carbon atoms, more preferably both hydrogen atoms or at least one of hydrogen atoms and the other is an alkyl group having 1 to 4 carbon atoms. Particularly preferred is Q⁶And Q⁷Are all hydrogen atoms.

Q¹Represents a C1-12 valent hydrocarbon group which may have a substituent. As the unsubstituted 1-valent hydrocarbon group, preferred are an alkyl group having 1 to 12 carbon atoms in which a part of the hydrogen atoms may be substituted with an aliphatic ring, an aromatic ring or an alkenyl group, and a hydrocarbon groupA cycloalkyl group having 3 to 8 carbon atoms which may be substituted by an aromatic ring, an alkyl group or an alkenyl group, and an aryl group having 6 to 12 carbon atoms which may be substituted by an aliphatic ring, an alkyl group or an alkenyl group.

Q¹When the alkyl group is an unsubstituted alkyl group, the alkyl group may be linear or branched, and the number of carbon atoms is more preferably 1 to 6.

An alkyl group having 1 to 12 carbon atoms which is substituted with an aliphatic ring, an aromatic ring or an alkenyl group as a part of a hydrogen atom, more preferably an alkyl group having 1 to 4 carbon atoms and having a cycloalkyl group having 3 to 6 carbon atoms, and an alkyl group having 1 to 4 carbon atoms and being substituted with a phenyl group, and particularly preferably an alkyl group having 1 or 2 carbon atoms and being substituted with a phenyl group. The alkyl group substituted with an alkenyl group means an alkenyl group as a whole but has no unsaturated bond between the 1-and 2-positions, and examples thereof include an allyl group and a 3-butenyl group.

The substituted hydrocarbon group is preferably a hydrocarbon group having 1 or more alkoxy, acyl, acyloxy, cyano, dialkylamino or chlorine atoms. The number of carbon atoms of the alkoxy group, acyl group, acyloxy group and dialkylamino group is preferably 1 to 6.

Preferred is Q¹Is an alkyl group having 1 to 6 carbon atoms wherein a part of the hydrogen atoms may be substituted with a cycloalkyl group or a phenyl group.

Particularly preferred is Q¹The alkyl group has 1 to 6 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and a tert-butyl group.

Q²～Q⁵Each independently represents a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 10 carbon atoms. The number of carbon atoms of the alkyl group and the alkoxy group is preferably 1 to 6, more preferably 1 to 4.

Preferably Q²And Q³At least one of them is an alkyl group, and more preferably both are alkyl groups. Q²Or Q³When not an alkyl group, a hydrogen atom is more preferable. Particularly preferred is Q²And Q³All of which are C1-C6 alkyl groups.

Preferably Q⁴And Q⁵At least one of them being a hydrogen atomMore preferably both are hydrogen atoms. Q⁴Or Q⁵When not a hydrogen atom, an alkyl group having 1 to 6 carbon atoms is preferable.

Z represents any of 2-valent groups represented by formulae (Z1) to (Z5).

In the formulae (Z1) to (Z5), Q⁸And Q⁹Each independently represents a C1-12 hydrocarbon group which may have a substituent. Q⁸And Q⁹It may be different groups, but preferably the same group.

The unsubstituted 1-valent hydrocarbon group is preferably an alkyl group having 1 to 12 carbon atoms, a part of hydrogen atoms of which may be substituted with an aliphatic ring, an aromatic ring or an alkenyl group, a cycloalkyl group having 3 to 8 carbon atoms, a part of hydrogen atoms of which may be substituted with an aromatic ring, an alkyl group or an alkenyl group, or an aryl group having 6 to 12 carbon atoms, a part of hydrogen atoms of which may be substituted with an aliphatic ring, an alkyl group or an alkenyl group.

Q⁸And Q⁹When the alkyl group is an unsubstituted alkyl group, the alkyl group may be linear or branched, and the number of carbon atoms is more preferably 1 to 6.

An alkyl group having 1 to 12 carbon atoms which is substituted with an aliphatic ring, an aromatic ring or an alkenyl group as a part of a hydrogen atom, more preferably an alkyl group having 1 to 4 carbon atoms and having a cycloalkyl group having 3 to 6 carbon atoms, and an alkyl group having 1 to 4 carbon atoms and being substituted with a phenyl group, and particularly preferably an alkyl group having 1 or 2 carbon atoms and being substituted with a phenyl group. The alkyl group substituted with an alkenyl group means an alkenyl group as a whole but has no unsaturated bond between the 1-and 2-positions, and examples thereof include an allyl group and a 3-butenyl group.

The substituted 1-valent hydrocarbon group is preferably a hydrocarbon group having 1 or more alkoxy, acyl, acyloxy, cyano, dialkylamino, or chlorine atoms. The number of carbon atoms of the alkoxy group, acyl group, acyloxy group and dialkylamino group is preferably 1 to 6.

Preferred is Q⁸And Q⁹Are all hydrogen atomsAn alkyl group having 1 to 6 carbon atoms which may be partially substituted with a cycloalkyl group or a phenyl group.

Particularly preferred is Q⁸And Q⁹All of the alkyl groups have 1 to 6 carbon atoms, and specific examples thereof include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, and tert-butyl group.

Q¹⁰～Q¹⁹Each independently represents a hydrogen atom or a substituted or unsubstituted 1-valent hydrocarbon group having 1 to 12 carbon atoms. The 1-valent hydrocarbon group having 1 to 12 carbon atoms which may have a substituent is the same as the above Q⁸、Q⁹The same hydrocarbon group. As the optionally substituted C1-12 hydrocarbon group, a C1-6 alkyl group is preferred.

More preferably Q¹⁰And Q¹¹All of them are alkyl groups having 1 to 6 carbon atoms, and particularly preferred are the same alkyl groups.

Preferably Q¹²、Q¹⁵All of which are hydrogen atoms or alkyl groups having 1 to 6 carbon atoms and having no substituent. Preferably 2 groups (Q) bound to the same carbon atom¹³And Q¹⁴、Q¹⁶And Q¹⁷、Q¹⁸And Q¹⁹) All of which are hydrogen atoms or alkyl groups having 1 to 6 carbon atoms.

As the compound represented by the formula (M), preferred are compounds wherein Y is an oxygen atom, Z is a group (Z1) or a group (Z2), and Y is a group represented by Q⁶And Q⁷Substituted methylene, compounds wherein Z is a group (Z1) or a group (Z5).

Z when Y is an oxygen atom, more preferably Q¹Is alkyl group of 1 to 6 carbon atoms, Q²And Q³Alkyl and Q each having a hydrogen atom or a carbon number of 1 to 6⁴、Q⁵A group (Z1) or a group (Z2) which are both hydrogen atoms. Particularly preferred is Q¹Is alkyl group of 1 to 6 carbon atoms, Q²And Q³Alkyl group and Q each having 1 to 6 carbon atoms⁴、Q⁵A group (Z1) or a group (Z2) which are both hydrogen atoms.

As Y is Q⁶And Q⁷Substituted methylene, Z being a radical (Z1) orCompounds of the group (Z5), preferably Q¹Is alkyl group of 1 to 6 carbon atoms, Q²And Q³All of which are hydrogen atoms or all of which are C1-C6 alkyl groups, Q⁴～Q⁷A group (Z1) or a group (Z5) both of which are hydrogen atoms, more preferably Q¹Is alkyl group of 1 to 6 carbon atoms, Q²～Q⁷A group (Z1) or a group (Z5) which are both hydrogen atoms.

The compound represented by the formula (M) is preferably a compound in which Y is an oxygen atom, and Z is a group (Z1) or a group (Z2), and particularly preferably a compound in which Y is an oxygen atom, and Z is a group (Z1).

Specific examples of the UV dye (M) include compounds represented by the following formulas (M-1) to (M-11).

The UV dye (U) preferably contains 1 or 2 or more types of UV dyes (U1). The UV dye (U) may contain other ultraviolet absorbing dyes in addition to the UV dye (U1). However, in this case, it is preferable that the effect obtained by the UV dye (U1) is not impaired.

The content of the UV pigment (U) in the absorbing layer is preferably determined so that the filter has a wavelength having a transmittance of 50% at a wavelength of 400 to 425nm of a spectral transmittance curve at an incident angle of 0 °. The UV dye (U) is contained in the absorbing layer by preferably 0.01 to 30 parts by mass, more preferably 0.05 to 25 parts by mass, and still more preferably 0.1 to 20 parts by mass, based on 100 parts by mass of the transparent resin.

(transparent resin (B))

Examples of the transparent resin (B) include acrylic resins, epoxy resins, ene-thiol resins, polycarbonate resins, polyether resins, polyarylate resins, polysulfone resins, polyethersulfone resins, polyparaphenylene resins, polyarylene ether phosphine oxide resins, polyimide resins, polyamideimide resins, polyolefin resins, cyclic olefin resins, and polyester resins. These resins may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

Among the above-mentioned resins, the transparent resin (B) is preferably a resin having a high glass transition temperature (Tg) from the viewpoints of transparency to visible light, solubility of the NIR dye (a) or the NIR dye (a) and the UV dye (U) in the transparent resin (B), heat resistance, and the like. Specifically, 1 or more selected from polyester resins, polycarbonate resins, polyethersulfone resins, polyarylate resins, polyimide resins, and epoxy resins are preferable. The transparent resin (B) is more preferably 1 or more selected from polyester resins and polyimide resins. The polyester resin is preferably a polyethylene terephthalate resin, a polyethylene naphthalate resin, or the like. In general, although a resin having a high glass transition temperature (Tg) has low adhesion to layers made of inorganic materials such as glass and dielectric multilayer films, in the present invention, sufficient adhesion to these layers can be secured by using the NIR dye (AI).

As the transparent resin (B), commercially available products can be used. Commercially available acrylic resins include OGSOL (registered trademark) EA-F5003 (trade name, manufactured by Osaka Gas Chemicals Co., Ltd.), polymethyl methacrylate, polyisobutyl methacrylate (trade name, manufactured by Tokyo chemical Co., Ltd.), BR50 (trade name, manufactured by Mitsubishi Rayon Co., Ltd.), and the like.

Further, examples of the polyester resin include OKP4HT, OKP4, B-OKP 2, OKP-850 (trade name, manufactured by Osakagas Chemicals Co., Ltd.), Vylon (registered trademark) 103 (trade name, manufactured by Toyo Kasei corporation), polyether sulfone resin such as SUMIKAEXCEL (registered trademark) PES4800 (trade name, manufactured by Sumitomo chemical Co., Ltd.), polycarbonate resin such as LeXan (registered trademark) ML9103 (trade name, manufactured by sabic corporation), EP5000 (product name, manufactured by MIUBISHI GAS CHEMICAL Co., Ltd.), SP3810 (product name, manufactured by Disk Kasei Co., Ltd.), SP1516 (product name, manufactured by Disk Kasei corporation), TS (product name, manufactured by Disk Kasei Co., Ltd.), xylex 7507 (registered trademark), olefin resin such as olefin resin (product name, manufactured by ART Kasei Co., Ltd.) (trade name, manufactured by Ring Co., Ltd. (registered trademark R., Ltd.) (trade name, manufactured by Toyo Kasei Co., Ltd., Japan), Examples of the polyimide resin include Neopulim (registered trademark) C3650 (trade name, manufactured by Mitsubishi GAS CHEMICAL Co., Ltd.), Neopulim C3630 (trade name, manufactured by Mitsubishi GAS CHEMICAL Co., Ltd.), and Neopulim C3450 (trade name, manufactured by Mitsubishi GAS CHEMICAL Co., Ltd.) (these polyimide resins may contain silica).

(other Components)

The absorbent layer may contain various optional components that such an absorbent layer usually contains, within a range that does not impair the effects of the present invention. Examples of the optional component include an adhesion-imparting agent, a color-tone correcting 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.

The adhesion-imparting agent is preferably a silane coupling agent having at least 1 selected from a vinyl group, an epoxy group, a styryl group, a methacrylic group, an acrylic group, an amino group, a urea group, a mercapto group, a sulfide group, and an isocyanate group.

The solvent for dissolving or dispersing the NIR dye (a), the UV dye (U), the transparent resin (B), and the like is not particularly limited as long as it is a dispersion medium capable of stably dispersing them or a solvent capable of dissolving them. In the present specification, the term "solvent" is used in a concept including both a dispersion medium and a solvent. The solvent can be used alone in 1 or mixed with 2 or more.

The amount of the solvent depends on the coating method of the coating liquid, but generally, the concentration of the solid components such as the transparent resin (B) and the NIR dye (a) in the coating liquid is preferably in the range of 2 to 50 mass%, more preferably in the range of 5 to 40 mass%, relative to the total amount of the coating liquid. If the solid content concentration is too low, coating unevenness is likely to occur. On the contrary, if the solid content concentration is too high, the coating appearance is liable to become poor.

The coating liquid may further contain a surfactant. By containing the surfactant, the appearance, particularly, voids due to fine bubbles, depressions due to adhesion of foreign substances and the like, and flicking in the drying step can be improved. The surfactant is not particularly limited, and any known surfactant such as a cationic surfactant, an anionic surfactant, and a nonionic surfactant can be used.

The coating liquid can be applied by a coating method such as a dip coating method, a casting coating method, a spray coating method, a spin coating method, a bead coating method, a wire bar coating method, a blade coating method, a roll coating method, a curtain coating method, a slit die coating method, a gravure coating method, a slit reverse coating method, a micro gravure coating method, an ink jet method, or a comma coating method. In addition, a bar coating method, a screen printing method, a flexographic printing method, or the like may be used.

Even when the filter includes a transparent base material including a glass substrate or the like as a component, the coating liquid may be applied to a base material different from the transparent base material, for example, a releasable support base material to form an absorption layer, and the absorption layer may be peeled from the support base material and attached to the transparent base material. The releasable supporting substrate may be in the form of a film or a plate, and the material is not particularly limited as long as it has releasability. Specifically, a glass plate, a mold-release-treated plastic film, a stainless steel plate, or the like can be used.

The absorbing layer may be formed into a film by extrusion molding depending on the type of the transparent resin, and a plurality of films thus formed may be laminated and integrated by hot pressing or the like. When the filter includes a transparent base material as a constituent member, the filter is then attached to the transparent base material.

In addition, in the coating of the coating liquid, the transparent substrate may be pretreated, and as the pretreatment agent, the silane coupling agent and the like may be used alone in 1 kind or mixed with 2 or more kinds.

In the filter, the thickness of the absorption layer is preferably 0.1 to 100 μm. When the absorbing layer is composed of a plurality of absorbing layers, the total thickness of the absorbing layers is preferably 0.1 to 100 μm. The thickness of the absorption layer is appropriately determined depending on the arrangement space and the like. If the thickness is less than 0.1. mu.m, the desired optical characteristics may not be sufficiently exhibited. When the thickness exceeds 100 μm, the flatness of the layer is lowered, and the absorption rate may vary in the plane, or the antireflection layer may be cracked. Therefore, the thickness of the absorption layer is more preferably 0.3 to 50 μm, and still more preferably 0.3 to 10 μm.

[ selection of wavelength-shielding layer ]

The selective wavelength shielding layer preferably has wavelength selective characteristics of transmitting visible light and shielding light having a wavelength other than the light shielding region of the absorption layer. In this case, the light-shielding region of the selective wavelength shielding layer may include a light-shielding region in the near infrared region of the absorption layer.

The selective wavelength shielding layer is composed of a dielectric multilayer film in which low refractive index films and high refractive index films are alternately laminated.

The high refractive index film preferably has a refractive index of 1.6 or more, more preferably 2.2 to 2.5, and examples thereof include Ta₂O₅、TiO₂、Nb₂O₅. Among them, TiO is preferable from the viewpoints of film formability, reproducibility of refractive index and the like, stability and the like₂。

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, and still more preferably 1.45 to 1.47, and examples thereof include SiO₂、SiO_xN_yAnd the like. SiO is preferred from the viewpoint of reproducibility, stability, economy and the like of film forming properties₂。

The dielectric multilayer film exhibits a function of controlling transmission and shielding of light in a specific wavelength region by interference of light, and has transmission/shielding characteristics having incident angle dependency. Generally, the wavelength of light shielded by reflection is shorter for light incident obliquely than for light incident perpendicularly (incident angle 0 °).

In the present embodiment, the dielectric multilayer film constituting the selective wavelength shielding layer preferably satisfies (iii-1) and (iii-2).

(iii-1) the transmittance of light having a wavelength of 420 to 695nm is 90% or more in each spectral transmittance curve at an incident angle of 0 DEG and 30 deg. The higher the transmittance of light having a wavelength of 420 to 695nm, the more preferable is 93% or more, the more preferable is 95% or more, and the further preferable is 97% or more.

(iii-2) wavelength λ in each spectral transmittance curve at incident angles of 0 ° and 30 °_bThe transmittance of light of nm-1100 nm is 1% or less (here, lambda)_bA maximum wavelength at which the transmittance of light having a wavelength of 650 to 800nm of the absorption layer is 1%). Wavelength lambda_bThe lower the transmittance of light of nm to 1100nm, the more preferably 0.5% or less.

If the wavelength-shielding layers are selected so as to satisfy (iii-1) and (iii-2), the spectral transmittance characteristics of the filter satisfying (iv-1) to (iv-6) can be easily obtained.

The selective wavelength shielding layer preferably has a transmittance that changes rapidly in a boundary wavelength region between the transmission wavelength and the blocking wavelength. For this purpose, the total number of layers of the dielectric multilayer film constituting the selective wavelength shielding layer, which are the low refractive index film and the high refractive index film, is preferably 15 or more, more preferably 25 or more, and still more preferably 30 or more. However, if the total number of stacked layers is increased, warpage of the dielectric multilayer film occurs, and the thickness of the dielectric multilayer film is increased, so that 100 layers or less, more preferably 75 layers or less, and still more preferably 60 layers or less are preferable.

The film thickness of the dielectric multilayer film is preferably thin in order to satisfy the above-described preferable number of stacked layers from the viewpoint of thinning of the optical filter. The film thickness of such a dielectric multilayer film depends on the selected wavelength shielding property, but is preferably 2 to 10 μm.

The selective wavelength shielding layer may have a predetermined selective wavelength shielding property by a single layer, that is, only 1 kind of dielectric multilayer film, or may have a predetermined selective wavelength shielding property by a plurality of layers. When a plurality of layers are provided, for example, the layers may be provided on one side of the absorbent layer, or may be provided on both sides of the absorbent layer.

[ anti-reflection layer ]

Examples of the antireflection layer include a dielectric multilayer film, an intermediate refractive index medium, and a moth-eye structure in which the refractive index gradually changes. Among them, a dielectric multilayer film is preferably used from the viewpoint of optical efficiency and productivity. The dielectric multilayer film used for the antireflection layer is obtained by alternately laminating a low refractive index film and a high refractive index film, similarly to the dielectric multilayer film used for the selective wavelength shielding layer.

[ transparent base Material ]

The transparent substrate may be in the form of a block, a plate or a sheet, and the thickness thereof is preferably 0.03 to 5mm, more preferably 0.05 to 1mm, from the viewpoint of light thinning, depending on the material of the structure.

The material of the transparent substrate is not particularly limited as long as visible light is transmitted, and glass, crystal, resin, or the like can be used. The transparent substrate is preferably glass from the viewpoint of shape stability concerning long-term reliability such as optical characteristics and mechanical characteristics of the optical filter, and from the viewpoint of workability and processability in the production of the filter.

Examples of the resin that can be used as the transparent substrate include polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyolefin resins such as polyethylene, polypropylene and ethylene-vinyl acetate copolymers, norbornene resins, acrylic resins such as polyacrylate and polymethyl methacrylate, polyurethane resins, vinyl chloride resins, fluorine resins, polycarbonate resins, polyvinyl butyral resins, polyvinyl alcohol resins, polyimide resins, and the like.

Examples of the glass that can be used for the transparent substrate include absorption glass (near-infrared ray absorption glass substrate) in which CuO or the like is added to fluorophosphate-based glass, phosphate-based glass, or the like, soda-lime glass, borosilicate glass, alkali-free glass, quartz glass, and the like. The term "phosphate glass" also includes glass in which a part of the glass skeleton is made of SiO₂The formed silicon phosphate glass.

Further, as a crystal material that can be used for the transparent substrate, birefringent crystals such as crystal, lithium niobate, and sapphire can be given.

Here, a specific composition example of CuO-containing glass used for the transparent substrate is described.

(1) In terms of mass%, relative to 100 parts by mass of the base glass, in other proportionsGlass containing 0.5 to 7 parts by mass of CuO, the base glass containing P₂O₅46～70％、AlF₃0.2～20％、LiF+NaF+KF 0～25％、MgF₂+CaF₂+SrF₂+BaF₂+PbF₂1-50%, wherein F is 0.5-32%, and O is 26-54%.

(2) Expressed in mass%, by P₂O₅25～60％、Al₂OF₃1～13％、MgO 1～10％、CaO 1～16％、BaO 1～26％、SrO 0～16％、ZnO 0～16％、Li₂O0～13％、Na₂O 0～10％、K₂O 0～11％、CuO 1～7％、ΣRO(R＝Mg、Ca、Sr、Ba)15～40％、ΣR’₂3 to 18% of O (R' ═ Li, Na, K) (wherein 39% or less of O is contained in a molar amount^2－Ion quilt F^－Ion-substituted).

(3) Expressed in mass%, contains P₂O₅5～45％、AlF₃1-35%, RF (R is Li, Na, K) 0-40%, R' F₂(R 'is Mg, Ca, Sr, Ba, Pb, Zn) 10-75%, R' F_m(R 'is La, Y, Cd, Si, B, Zr, Ta, m is a number corresponding to the valence of R') (0-15% (wherein 70% or less of the total amount of fluorides can be substituted by oxides) and CuO (0.2-15%).

(4) Expressed as% of cation, contains P ⁵⁺11～43％、Al³⁺1-29%, 14-50% of R cation (the total amount of Mg, Ca, Sr, Ba, Pb and Zn ions), 0-43% of R 'cation (the total amount of Li, Na and K ions), 0-8% of R' cation (the total amount of La, Y, Gd, Si, B, Zr and Ta ions) and Cu²⁺0.5 to 13%, and further contains F in terms of anion%^－17-80% of glass.

(5) Expressed as% of cation, contains P⁵⁺23～41％、Al³⁺4～16％、Li ⁺11～40％、Na⁺3～13％、R²⁺(Mg²⁺、Ca²⁺、Sr²⁺、Ba²⁺、Zn²⁺Total amount of) 12 to 53% and Cu²⁺2.6 to 4.7%, and further contains F in terms of anion%^－25 to 48% and O^2－52～75% of glass.

(6) A glass comprising, in terms of mass%, 0.1 to 5 parts by mass of CuO per 100 parts by mass of a base glass consisting of P₂O₅70～85％、Al₂O₃8～17％、B₂O₃1～10％、Li₂O 0～3％、Na₂O 0～5％、K₂0 to 5% of O, wherein Li₂O+Na₂O+K₂O 0.1～5％、SiO₂0 to 3% of the composition.

Examples of commercially available glass include NF-50E, NF-50 EX and NF-50T, NF-50 TX (trade name, manufactured by Asahi glass Co., Ltd.), glass (2) includes BG-60 and BG-61 (see above, trade name, manufactured by Schott) and glass (5) includes CD5000 (trade name, manufactured by HOYA).

The CuO-containing glass described above may further contain a metal oxide. As the metal oxide, for example, Fe is contained₂O₃、MoO₃、WO₃、CeO₂、Sb₂O₃、V₂O₅And so on, the CuO-containing glass has ultraviolet absorption characteristics. The content of these metal oxides is preferably selected from Fe based on 100 parts by mass of the CuO-containing glass₂O₃、MoO₃、WO₃And CeO₂At least 1 of them being Fe₂O₃0.6 to 5 parts by mass of MoO₃0.5 to 5 parts by mass of WO₃1 to 6 parts by mass of CeO₂2.5 to 6 parts by mass, or Fe₂O₃And Sb₂O₃These 2 are Fe₂O₃0.6 to 5 parts by mass of + Sb₂O₃0.1 to 5 parts by mass or V₂O₅And CeO₂These 2 are V₂O₅0.01 to 0.5 part by mass + CeO₂1 to 6 parts by mass.

When the filter includes glass or absorptive glass as the transparent substrate 14, a dielectric layer (not shown) may be provided between the glass or absorptive glass (transparent substrate 14) and the absorptive layer 11. The dielectric layer is a layer made of a dielectric material, and preferably has a thickness of 30nm or more. By having the dielectric layer, the durability of the absorption layer 11 in the present filter can be improved. The thickness of the dielectric layer is more preferably 100nm or more, and still more preferably 200nm or more. The thickness of the dielectric layer is not particularly limited, but is preferably 2000nm or less, more preferably 1000nm or less, from the viewpoint of ease of design and ease of production.

For example, when a transparent substrate made of glass contains alkali atoms such as Na atoms and K atoms, and the alkali atoms diffuse into the absorption layer 11 to deteriorate the optical characteristics and durability of the absorption layer 11, the dielectric layer can function as an alkali barrier film to improve the durability of the filter. In the above case, SiO is an appropriate example of the dielectric layer₂、SiO_x、Al₂O₃And the like.

The filter may further include an adhesive film between the transparent substrate 14 and the absorbing layer 11. The adhesive film may be selected from MgF₂、CaF₂、LaF₃、NdF₃、CeF₃、Na₅Al₃F₁₄、Na₃AlF₆、AlF₃、BaF₂And YF₃At least 1 material selected from. As described above, for example, the dielectric layer (alkali barrier film) or the adhesive film described above, or both the dielectric layer and the adhesive film may be provided between the transparent substrate made of glass and the absorption layer 11. In the present specification, when the dielectric layer and/or the adhesive film are provided between the glass or the near infrared ray absorbing glass (absorbing glass) and the absorbing layer 11 as described above, a structure in which the dielectric layer and/or the adhesive film are provided on the glass or the near infrared ray absorbing glass is also regarded as a "transparent substrate".

The optical characteristics of the transparent substrate are preferably those of the present invention as an NIR filter laminated with the above-described absorption layer, the above-described selective wavelength shielding layer, and the like.

When the above-described absorption layer is laminated on the principal surface of the transparent substrate, the laminated surface is subjected to surface treatment with a silane coupling agent. By using the transparent base material subjected to the surface treatment with the silane coupling agent, the adhesion to the absorption layer can be improved. As the silane coupling agent, for example, the same silane coupling agent as used in the absorption layer described above can be used.

The filter can be used as an imaging device such as a digital camera, an NIR filter such as an automatic exposure meter, an NIR filter for a PDP, and the like. The filter is suitable for use in a solid-state imaging device such as a digital camera.