CN117597611A

CN117597611A - Optical filter

Info

Publication number: CN117597611A
Application number: CN202280046805.2A
Authority: CN
Inventors: 长田崇; 梨子公贵; 盐野和彦
Original assignee: Asahi Glass Co Ltd
Current assignee: AGC Inc
Priority date: 2021-07-21
Filing date: 2022-07-14
Publication date: 2024-02-23
Also published as: WO2023002924A1; JPWO2023002924A1; TW202309559A

Abstract

In one embodiment of the optical filter of the present invention, the optical filter includes a transparent substrate having a first main surface and a first light absorbing layer provided on the first main surface side of the transparent substrate, wherein the first light absorbing layer includes a near infrared ray absorbing dye having a maximum absorption wavelength in a wavelength range of 650nm to 760nm and having a molecular weight of 2000 or less, and an inorganic material.

Description

Optical filter

Technical Field

The present invention relates to a filter.

Background

Imaging devices such as digital cameras and digital video cameras are provided with solid-state imaging elements (CCD, CMOS, etc.) for sensing persons, scenes, etc. The solid-state imaging element exhibits a stronger sensitivity to infrared light than to human vision. Therefore, in order to make the image obtained by the solid-state imaging element approach the human visual sensitivity, an optical filter such as a near infrared cut filter is further provided in the imaging device.

In general, such a filter is configured by providing a light absorbing layer shielding near infrared rays on a transparent substrate. For example, patent document 1 discloses a near infrared cut filter including a laminate sheet having a resin layer on at least one surface of a glass substrate, and a dye as a near infrared absorber in the resin layer.

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2012-103340

Disclosure of Invention

Problems to be solved by the invention

In recent years, particularly with the increase in performance of imaging devices mounted in smart phones, there has been a demand for optical filters having excellent light resistance.

However, in the near infrared cut filter of patent document 1, since the resin layer contains a dye as a near infrared absorbent, there is a possibility that the dye reacts with hydroxyl groups in the resin due to sunlight or indoor light to cause photooxidation and deterioration. Therefore, the light resistance of the near infrared cut filter of patent document 1 may be insufficient.

An object of one embodiment of the present invention is to provide a filter having excellent light resistance and near infrared ray shielding characteristics.

Means for solving the problems

Effects of the invention

One embodiment of the present invention can provide a filter having excellent light resistance and near infrared ray shielding characteristics.

Drawings

Fig. 1 is a schematic view of a cross section of a filter according to an embodiment of the present invention.

Fig. 2 is a schematic cross-sectional view of a first modification of the filter according to the embodiment of the present invention.

Fig. 3 is a schematic cross-sectional view of a second modification of the filter according to the embodiment of the present invention.

Fig. 4 is a schematic cross-sectional view of a third modification of the filter according to the embodiment of the present invention.

Fig. 5 is a schematic cross-sectional view of a fourth modification of the filter according to the embodiment of the present invention.

Fig. 6 is a schematic cross-sectional view of a fifth modification of the filter according to the embodiment of the present invention.

Fig. 7 is a graph showing spectral transmittance curves before and after the light resistance test of the filter in example 1.

Fig. 8 is a graph showing spectral transmittance curves before and after the light resistance test of the filter in example 2.

Fig. 9 is a graph showing spectral transmittance curves before and after the light resistance test of the filter in example 3.

Fig. 10 is a graph showing spectral transmittance curves before and after the light resistance test of the filter in example 4.

Fig. 11 is a graph showing a spectral transmittance curve of the filter in example 5.

Fig. 12 is a graph showing a spectral transmittance curve of the filter in example 6.

Fig. 13 is a graph showing a spectral transmittance curve of the filter in example 7.

Fig. 14 is a graph showing a spectral transmittance curve of the filter in example 8.

Fig. 15 is a graph showing spectral transmittance curves before and after the light resistance test of the filter in example 9.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail.

A filter according to an embodiment will be described. Fig. 1 is a schematic view of a cross section of a filter according to an embodiment of the present invention. As shown in fig. 1, the optical filter 10 has a transparent substrate 1 and a first light absorbing layer 2 provided on one main surface (first main surface) of the transparent substrate 1.

[ transparent substrate ]

The transparent substrate 1 may be made of any material as long as it is transparent to visible light (high transmittance). For example, the transparent substrate 1 may be composed of glass (white glass, near infrared ray absorbing glass, or the like) or resin.

[ first light-absorbing layer ]

The first light absorbing layer 2 is a layer that absorbs near infrared rays. The first light-absorbing layer 2 is a layer containing a near-infrared ray absorbing dye (a) that absorbs near-infrared rays and an inorganic material (B), and as a typical example, the first light-absorbing layer 2 is a layer formed by dispersing the near-infrared ray absorbing dye (a) in the inorganic material (B). In other words, the first light absorbing layer 2 is a layer formed by mixing the inorganic material (B) and the near infrared ray absorbing pigment (a). The infrared absorbing pigment (a) may be uniformly dispersed in the inorganic material (B), or may be different in concentration in the orthogonal direction of the first main surface of the transparent substrate 1 (the thickness direction of the transparent substrate 1).

(near infrared ray absorption pigment)

The near infrared ray absorbing pigment (A) has a maximum absorption wavelength (hereinafter referred to as "lambda") within a wavelength range of 650nm to 760nm _max ") and having a molecular weight of 2000 or less, is not particularly limited. Lambda is the sum of the values of lambda _max An absorption peak having an absorption peak (hereinafter referred to as "lambda _max Absorption peak of (c). Near infraredThe absorption curve of the line absorption pigment (A) preferably has lambda except in the wavelength range of 650nm to 760nm _max In addition, absorption in the visible light region is small, and lambda _max The slope of the absorption peak on the visible side of (2) is steep. Furthermore lambda _max The absorption peak of (2) is preferably gentle on the long wavelength side.

Lambda of near infrared ray absorbing pigment (A) _max The detection can be performed by using an absorption curve in a wavelength range of 400nm to 850nm measured by an ultraviolet-visible near infrared spectrophotometer (model: V770, manufactured by Japanese Specification Co., ltd.) using a solution obtained by dissolving the near infrared absorbing dye (A) in methylene chloride. In the present specification, unless otherwise specified, measurement of the absorption curve is performed under the condition of an incident angle of 0 °.

The near infrared ray absorption dye (a) has a maximum absorption wavelength in a wavelength range of 650nm to 760nm, and thus can impart an excellent ability to absorb light in the near infrared ray wavelength range (700 nm to 1100 nm) to the filter 10. In addition, the near infrared ray absorbing dye (a) has a molecular weight of 2000 or less, and can be formed on a transparent substrate at a low temperature. Therefore, thermal degradation of the near infrared ray absorbing dye (a) can be suppressed, and the filter 10 can obtain desired near infrared ray absorbing characteristics.

Examples of the near infrared ray absorbing dye (a) include: cyanine compounds, phthalocyanine compounds, naphthalocyanine compounds, dithiol metal complex compounds, diimmonium compounds, polymethine compounds, phthalide compounds, naphthoquinone compounds, anthraquinone compounds, indophenol compounds, squaraine compoundsSalt compounds, and the like.

Of these, more preferable is squaraineSalt compounds, cyanine compounds and phthalocyanine compounds, particularly preferably squaraine ++>And (3) a salt compound. Comprises->The near infrared ray absorption dye (A) of the salt compound has small absorption in the visible light region, lambda in the absorption curve _max The absorption peak of (2) has a steep gradient on the visible light side, and is high in storage stability and stability to light, and is therefore preferable. The near infrared ray absorption dye (A) containing a cyanine compound has a small absorption in the visible light region in the absorption curve, and is represented by lambda _max The absorbance at the long wavelength side in the nearby wavelength range is high, and is therefore preferable. In addition, cyanine compounds have been known as pigments for recording color such as CD-R since ancient times, and are low in cost and can ensure long-term stability by salt formation. The near infrared absorbing dye (a) containing the phthalocyanine compound is preferable because it is excellent in heat resistance and weather resistance.

Regarding as the squaraineThe near infrared absorbing dye (a) of the salt compound includes, specifically: is selected from squaraine represented by the following formula (F1)>At least one of the salt compounds. In this specification, the compound represented by the formula (F1) is also referred to as a compound (F1). The same applies to other compounds.

The compound (F1) is in squaric acidIn squaric acid having a structure in which a benzene ring is bonded to the left and right sides of a salt skeleton, and a nitrogen atom is bonded to the 4-position of the benzene ring and a saturated heterocyclic ring containing the nitrogen atom is formed>Salt compound, wherein the compound (F1) has the above-mentioned near infraredA compound having light absorption characteristics of the line-absorbing dye (A). In the compound (F1), the substituent of the benzene ring can be appropriately adjusted within the following range according to other required characteristics such as the improvement of the solubility in the solvent (hereinafter, also referred to as "main solvent") used in forming the first light absorbing layer and the inorganic material (B).

The symbols in the formula (F1) are as follows. R is R ⁴ And R is ⁶ Each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an acyloxy group having 1 to 10 carbon atoms, an aryl group having 6 to 11 carbon atoms, an aralkyl group having 7 to 18 carbon atoms which may have a substituent and may have an oxygen atom between carbon atoms, -NR ⁷ R ⁸ (R ⁷ And R is ⁸ Each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, -C (=O) -R ⁹ (R ⁹ A hydrocarbon group of 1 to 25 carbon atoms which is a hydrogen atom, a halogen atom, a hydroxyl group, a hydrocarbon group which may have a substituent and may contain an unsaturated bond, an oxygen atom, a saturated or unsaturated ring structure between carbon atoms), or-NHR ¹⁰ or-SO ₂ -R ¹⁰ (R ¹⁰ Each of which is a hydrocarbon group having 1 to 25 carbon atoms and having a ring structure which may be unsaturated, oxygen atom, saturated or unsaturated, and which may be substituted with a halogen atom, hydroxyl group, carboxyl group, sulfo group or cyano group), or a group (R) represented by the following formula (S) ⁴¹ And R is ⁴² Independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms. k is 2 or 3).

R ¹ And R is ² Can be linked to each other and form together with the nitrogen atom a five-or six-membered heterocyclic ring A, R ² And R is ⁵ Can be connected with each other and withThe nitrogen atoms together form a five-or six-membered heterocyclic ring B, and R ¹ And R is ³ May be linked to each other and form together with the nitrogen atom a five-or six-membered heterocyclic ring C.

With respect to R in the case of formation of the heterocyclic ring A ¹ And R is ² The divalent group-Q-bonded thereto represents an alkylene or 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.

With respect to R in the case of formation of heterocyclic ring B ² And R is ⁵ And R in the case of formation of heterocycle C ¹ And R is ³ As R ² And R is ⁵ Divalent group-X bonded ¹ -Y ¹ -and R ¹ And R is ³ Divalent group-X bonded ² -Y ² - (nitrogen-bonded side being X ¹ And X ² )，X ¹ And X ² Each is a group represented by the following formula (1 x) or (2 x), Y ¹ And Y ² Each is a group represented by any one selected from the following formulas (1 y) to (5 y). At X ¹ And X ² In the case where each is a group represented by the following formula (2 x), Y ¹ And Y ² Each may be a single bond.

In the formula (1 x), 4Z's each 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-NR ²⁸ R ²⁹ (R ²⁸ And R is ²⁹ Each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms). R is R ²¹ ～R ²⁶ Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms, R ²⁷ Represents an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms.

R ⁷ 、R ⁸ 、R ⁹ 、R ⁴ 、R ⁶ 、R ²¹ ～R ²⁷ In the presence ofR in the absence of heterocyclic ring formation ¹ ～R ³ And R is ⁵ Each may be bonded to each other with any of them to form a five-membered ring or a six-membered ring. R is R ²¹ And R is ²⁶ Can be directly bonded, R ²¹ And R is ²⁷ Can be directly bonded.

R in the absence of formation of heterocyclic ring ¹ And R is ² Each 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, or an aryl group or an aralkyl group having 6 to 11 carbon atoms. R in the absence of formation of heterocyclic ring ³ And R is ⁵ Each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms.

Hereinafter, the heterocyclic ring a may be simply referred to as ring a. The same applies to the heterocycles B and C.

In the compound (F1), R ⁴ And R is ⁶ Each independently represents the above atom or group. Examples of the halogen atom include: fluorine atom, chlorine atom, bromine atom, etc. The alkyl group may be any of linear, branched, and cyclic. R is R ⁴ And R is ⁶ Preferably either is a hydrogen atom and the other is-NR ⁷ R ⁸ Is a combination of (a) and (b).

In the case of the compound (F1) having only ring A of the rings A to C, only ring B and ring C, and having rings A to C, -NR ⁷ R ⁸ Can be introduced into R ⁴ And R is ⁶ Any one of the above. In the case of the compound (F1) having only the ring B, only the rings A and B, -NR ⁷ R ⁸ Preferably is introduced into R ⁴ . Similarly, in the case where the compound (F1) has only the ring C, only the ring A and the ring C, -NR ⁷ R ⁸ Preferably is introduced into R ⁶ 。

as-NR ⁷ R ⁸ From the viewpoint of solubility in the main solvent and the inorganic material (B), it is preferable that-NHC (=o) -R ⁹ . As R ⁹ Preferably an alkyl group having 1 to 20 carbon atoms which may have a substituent, an aryl group having 6 to 10 carbon atoms which may have a substituent, or an aryl group which may have a substituentAnd an aralkyl group having 7 to 18 carbon atoms which may have an oxygen atom between carbon atoms. As the substituent, there may be mentioned: fluorine atom, 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 R ⁹ Among these groups, preferred is an alkyl group having 1 to 17 carbon atoms selected from the group consisting of linear, branched and cyclic alkyl groups which may be substituted with a fluorine atom; phenyl 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; and an aralkyl group having a phenyl group which may be substituted with an alkyl group having 1 to 6 carbon atoms and/or an alkoxy group having 1 to 6 carbon atoms, wherein the alkyl group may have 7 to 18 carbon atoms and the alkoxy group may have 1 to 6 carbon atoms.

In the compound (F1), R is as follows ¹ And R is ² 、R ² And R is ⁵ And R is ¹ And R is ³ Five-membered or six-membered rings a, B and C, each of which is bonded to each other, may be formed at least in 1 or 2 or 3 of them.

R in the case of non-ring formation ¹ And R is ² Each 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, or an aryl group or an aralkyl group having 6 to 11 carbon atoms. The alkyl group may be any of linear, branched, and cyclic. As the substituent, there may be mentioned: hydroxy, alkoxy having 1 to 3 carbon atoms, and acyloxy having 1 to 3 carbon atoms. R in the case of non-ring formation ³ And R is ⁵ Each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms. Among these, R is ¹ 、R ² 、R ³ 、R ⁵ From the viewpoint of solubility in the main solvent and the inorganic material (B), an alkyl group having 1 to 3 carbon atoms is preferable, and methyl group and 2-propyl group are particularly preferable.

In addition, in the compound (F1), in squaric acidA group R of benzene ring bonded from left to right of salt skeleton ¹ ～R ⁶ May be different from each other in the left-right direction, but is preferably the same in the left-right direction.

The compound (F1) includes a compound (F1-1) represented by the formula (F1-1) having a resonance structure having a structure represented by the general formula (F1).

Wherein the symbols in the formula (F1-1) are the same as defined in the above formula (F1).

As the compound (F1), more specifically, there may be mentioned: a compound represented by the following formula (F11) having only ring B as a ring structure, a compound represented by the following formula (F12) having only ring a as a ring structure, and a compound represented by the following formula (F13) having both ring B and ring C as ring structures. The compound represented by the following formula (F11) has only ring C as a ring structure and R in the compound (F1) ⁶ is-NR ⁷ R ⁸ The same compound as the above. The compound represented by the following formula (F11) and the compound represented by the following formula (F13) are compounds described in the specification of U.S. Pat. No. 5543086.

The symbols in the formulae (F11) to (F13) are the same as defined in the above formula (F1), and the preferable embodiment is the same.

In the compound (F11), X is ¹ Preferably, the hydrogen atom represented by the above (2 x) may be an ethylene group substituted with an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms. In this case, as the substituent, a carbon atom is preferableAlkyl groups having 1 to 3 are more preferably methyl groups. As X ¹ Specifically, it is possible to list: - (CH) ₂ ) ₂ -、-CH ₂ -C(CH ₃ ) ₂ -、-CH(CH ₃ )-C(CH ₃ ) ₂ -、-C(CH ₃ ) ₂ -C(CH ₃ ) ₂ -and the like. As-NR in the Compound (F11) ⁷ R ⁸ preferably-NH-C (=O) -CH ₃ 、-NH-C(＝O)-C ₆ H ₁₃ 、-NH-C(＝O)-C ₆ H ₅ 、-NH-C(＝O)-CH(C ₂ H ₅ )-C ₄ H ₉ 、-NH-C(＝O)-C(CH ₃ ) ₂ -C ₂ H ₅ 、-NH-C(＝O)-C(CH ₃ ) ₂ -C ₃ H ₇ 、-NH-C(＝O)-C(CH ₃ ) ₂ -(CH ₂ ) ₃ -O-C ₆ H ₃ (CH ₃ ) ₂ Etc.

Examples of the compound (F11) include: and compounds represented by the following formulas (F11-1), (F11-2), (F11-3), (F11-4), (F11-5), (F11-6), (F11-7) and (F11-8), respectively. Among these, the compound (F11-2), the compound (F11-3), the compound (F11-4), the compound (F11-5), the compound (F11-6), the formula (F11-7) and the formula (F11-8) are more preferable from the viewpoint of high solubility in the main solvent and the inorganic material (B).

In the compound (F12), Q is an alkylene group having 4 or 5 carbon atoms or an alkyleneoxy group having 3 or 4 carbon atoms which 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. In the case of an alkyleneoxy group, the position of oxygen is preferably a position other than the N-adjacent position. The group Q is preferably a butylene group which may be substituted with an alkyl group having 1 to 3 carbon atoms, particularly a methyl group.

In the compound (F12), -NR ⁷ R ⁸ preferably-NH-C (=O) - (CH ₂ ) _m -CH ₃ (m is 0 to 19), -NH-C (=O) -Ph-R ¹⁰ (-Ph-represents phenylene, R) ¹⁰ Represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms, the hydrogen atom of which may be substituted with a fluorine atom), or the like.

Here, lambda of the compound (F12) _max On the longer wavelength side of the above wavelength range, therefore, if the compound (F12) is used, the transmission region of the visible light band can be widened. Examples of the compound (F12) include: and compounds represented by the following formulas (F12-1), (F12-2) and (F12-3).

In the compound (F13), X is ¹ And X ² Independently, an ethylene group in which a hydrogen atom represented by the above (2 x) may be substituted with an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms is preferable. In this case, the substituent is preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group. As X ¹ And X ² Specifically, it is possible to list: - (CH) ₂ ) ₂ -、-CH ₂ -C(CH ₃ ) ₂ -、-CH(CH ₃ )-C(CH ₃ ) ₂ -、-C(CH ₃ ) ₂ -C(CH ₃ ) ₂ -and the like. As Y ¹ And Y ² Independently, there may be mentioned: -CH ₂ -、-C(CH ₃ ) ₂ -、-CH(C ₆ H ₅ )-、-CH((CH ₂ ) _m CH ₃ ) - (m is 0 to 5), etc. In the compound (F13), -NR ⁷ R ⁸ preferably-NH-C (=O) -C _m H _2m+1 (m is 1 to 20, C) _m H _2m+1 Can be any of linear, branched and cyclic), NH-C (=O) -Ph-R ¹⁰ (-Ph-represents phenylene, R) ¹⁰ Represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a perfluoroalkyl group having 1 to 3 carbon atoms), or the like.

Examples of the compound (F13) include: and compounds represented by the following formulas (F13-1) and (F13-2), respectively.

As the near infrared absorbing dye (A), a squaraine represented by the following formula (F2) can be usedAnd (3) a salt compound. The formula (F2) represents a compound in which any one of ring A, ring B, and ring C is not formed in the formula (F1) (wherein R ¹ ～R ⁶ As described below).

The symbols in the formula (F2) are as follows. R is R ¹ And R is ² Each independently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms which may have a substituent, an allyl group which may have a substituent, or an aryl group or an aralkyl group having 6 to 11 carbon atoms. R is R ³ And R is ⁵ Each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms. R is R ⁴ And R is ⁶ Each 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, or-NR ⁷ R ⁸ (R ⁷ And R is ⁸ Each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or-C (=O) -R ⁹ (R ⁹ Is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, or a compound having a substituentAryl having 6 to 11 carbon atoms of the substituent or aralkyl having 7 to 18 carbon atoms which may have a substituent and may have an oxygen atom between carbon atoms).

Examples of the compound (F2) include: and compounds represented by the formula (F2-1) and the formula (F2-2).

As the near infrared ray absorbing dye (A), a squaraine represented by the following formula (F3) may be usedAnd (3) a salt compound.

The compound (F1), the compound (F2), and the compound (F3) such as the compound (F11), the compound (F12), and the compound (F13) can be produced by a known method. The compound (F11) such as the compound (F11-1) can be produced by the method described in the specification of U.S. Pat. No. 5543086. The compound (F12) can be produced by the method described in J.org.chem.2005,70 (13), 5164-5173, for example.

In which the near infrared ray absorbing pigment (A) is squaric acidIn the case of the salt compound, a commercially available product can be used. Examples of the commercial products include: s2098, S2084 (trade name, manufactured by FEW Chemicals), and the like.

The near infrared absorbing dye (a) as the cyanine compound may be specifically: at least one kind selected from cyanine compounds represented by the following formula (F4).

Wherein the symbols in the formula (F4) are as follows. R is R ¹¹ Each independently represents an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylsulfonyl group having 1 to 20 carbon atoms, or an anionic species thereof.

R ¹² And R is ¹³ Each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.

Z represents PF ₆ 、ClO ₄ 、R ^f -SO ₂ 、(R ^f -SO ₂ ) ₂ -N(R ^f Alkyl group having 1 to 8 carbon atoms, in which at least one hydrogen atom is substituted with a fluorine atom), or BF ₄ 。

R ¹⁴ 、R ¹⁵ 、R ¹⁶ And R is ¹⁷ Each independently represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms. n represents an integer of 1 to 6.

R in the compound (F4) ¹¹ Preferably an alkyl group having 1 to 20 carbon atoms, R ¹² And R is ¹³ Each independently is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. R is R ¹⁴ 、R ¹⁵ 、R ¹⁶ And R is ¹⁷ Each independently is preferably a hydrogen atom, and the number of n is preferably 1 to 4. The left and right structures sandwiching n repeating units may be different, but the same structure is preferable.

As the compound (F4), more specifically, there can be exemplified: a compound represented by the following formula (F4-1), a compound represented by the following formula (F4-2), and the like. Z-represents an anion as in the above-mentioned Z-in (F4).

As the near infrared absorbing dye (a) which is a cyanine compound, commercially available products can be used. Examples of the commercial products include: ADS680HO (trade name, manufactured by American dye company), S0830 (trade name, manufactured by FEW Chemicals company), S2137 (trade name, manufactured by FEW Chemicals company), and the like.

Further, examples of the phthalocyanine compound which can be used as the near infrared absorbing dye (a) include: FB22 (trade name, manufactured by mountain chemical industries, co., ltd.), TXEX720 (trade name, manufactured by japan catalyst co., ltd.), PC142c (trade name, manufactured by mountain chemical co., ltd.), and the like.

In the present embodiment, as the near infrared ray absorbing pigment (a), one compound selected from a plurality of compounds having a maximum absorption wavelength in a wavelength range of 650nm to 760nm may be used alone, or two or more compounds may be used in combination. The near infrared ray absorbing dye (a) preferably contains one or more of the above near infrared ray absorbing dyes (a). The near infrared ray absorbing dye (a) may contain an optional near infrared ray absorbing dye as required. In the case of using a plurality of near infrared ray absorbing pigments as the near infrared ray absorbing pigment (a), it is preferable to use the near infrared ray absorbing pigments in combination so that they exhibit the maximum absorption wavelength in the wavelength range of 650nm to 760 nm. In addition, it is preferable to use a near infrared ray absorbing pigment in combination so that the absorption in the visible light region is small, λ in the absorption curve _max The slope of the absorption peak on the visible side is steep and the slope on the long wavelength side is gentle. Further, a near infrared ray absorbing dye selected from a plurality of compounds having a maximum absorption wavelength outside the wavelength range of 650nm to 760nm may be used in combination with the near infrared ray absorbing dye (A).

(inorganic Material)

As the inorganic material (B), an inorganic material having a refractive index of 1.38 to 2.20 at a wavelength of 500nm is preferable.

The inorganic material (B) may specifically be: silica, alumina, magnesium fluoride, sodium fluoride, lanthanum fluoride, lithium fluoride, calcium fluoride, barium fluoride, lanthanum oxide, cerium oxide, germanium oxide, indium oxide, magnesium oxide, zirconium oxide, tantalum oxide, yttrium oxide, tungsten oxide, zinc oxide, ITO, a material in which the valence of these compounds is changed, a composite material in which the refractive index is adjusted by mixing any of these compounds as a main component, or the like. Among these, the smaller the refractive index difference from the transparent substrate 1, the easier the spectral characteristics are intentionally adjusted, and from the viewpoint of ensuring practical reliability, the inorganic material is preferably one or more selected from silica, alumina, and magnesium fluoride. In the case of using an inorganic material having a refractive index of 1.38 to 2.20 at a wavelength of 500nm as the inorganic material (B), one or more of these inorganic materials may be used alone or two or more of them may be used in combination as long as the refractive index as a whole falls within this range.

In the filter 10, since the matrix material in which the near infrared ray absorbing dye (a) is dispersed is an inorganic material, the hydroxyl groups are smaller than those in the case where the matrix material is a resin, and photooxidation of the near infrared ray absorbing dye (a) by sunlight or indoor light can be suppressed. Therefore, the filter 10 can exhibit excellent light resistance and near infrared ray shielding characteristics.

The film thickness of the first light absorbing layer 2 is not particularly limited, and is appropriately determined according to the application, that is, the arrangement space in the device to be used, the required absorption characteristics, and the like. The film thickness of the first light absorbing layer 2 is preferably 0.1 μm to 100 μm. When the film thickness is less than 0.1 μm, near infrared ray absorption ability may not be sufficiently exhibited. If the film thickness is larger than 100 μm, the flatness of the film may be lowered, and the absorption rate may vary. The film thickness is more preferably 0.2 μm to 0.7. Mu.m. If the film thickness is within this range, a sufficient near infrared ray absorption capability can be obtained. In the present specification, the film thickness refers to a physical film thickness.

The first light-absorbing layer 2 may contain optional components in addition to the near infrared ray-absorbing pigment (a) and the inorganic material (B) as required within a range that does not hinder the effects of the present invention. As optional ingredients, specifically, there may be mentioned: near infrared to infrared absorbers, color tone correction pigments, ultraviolet absorbers, leveling agents, antistatic agents, heat stabilizers, light stabilizers, antioxidants, and the like. The content of these optional components in the first light absorbing layer 2 is preferably 15 parts by mass or less each with respect to 100 parts by mass of the inorganic material (B).

As an optional component, the above-mentioned optional component preferably contains an ultraviolet absorber. The first light absorbing layer 2 can exhibit both a function of absorbing near infrared rays and a function of absorbing ultraviolet rays by containing an ultraviolet absorber.

Examples of the ultraviolet absorber include: triazine compound, indole compound, azomethine compound, benzotriazole compound, merocyanine compound and benzoUltraviolet absorbing pigments (C) such as azole compounds, inorganic ultraviolet absorbers, etc. The ultraviolet absorber is preferably the ultraviolet absorbing dye (C) described above, in terms of high absorbance, being able to effectively absorb the desired ultraviolet band, and being high in sharpness, and therefore being less likely to cause a loss in transmittance in the visible light band.

Among the above, preferred are merocyanines and benzonitrile as the ultraviolet absorbing pigment (C)Azole compounds.

The ultraviolet absorbing dye (C) is preferably a merocyanine compound represented by the following formula (U1).

The symbols in the formula (U1) are as follows. Y represents R ⁶ And R is ⁷ Substituted methylene, or an oxygen atom. R is R ¹ Represents a monovalent hydrocarbon group having 1 to 12 carbon atoms which may have a substituent. R is R ² ～R ⁷ Each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms. X represents any one of divalent groups represented by the following formulas (X1) to (X5) (wherein R ⁸ And R is ⁹ Each independently ofIn the standing place, a monovalent hydrocarbon group of 1 to 12 carbon atoms which may have a substituent is represented by R ¹⁰ ～R ¹⁹ Each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms which may have a substituent).

In formula (U1), R is preferably ¹ 、R ⁸ And R is ⁹ Each independently is an alkyl group having 1 to 6 carbon atoms, a part of which may be substituted with a cycloalkyl group or a phenyl group, R ² ～R ⁷ And R is ¹⁰ ～R ¹⁹ Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

In formula (U1), R is preferably ¹ 、R ⁸ And R is ⁹ Each independently is an alkyl group having 1 to 6 carbon atoms, R ² ～R ⁷ And R is ¹⁰ ～R ¹⁹ Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

Examples of the compound (U1) include: and compounds represented by the following formulas (U1-1), formula (U1-2), formula (U1-3), formula (U1-4), formula (U1-5) and formula (U1-6), respectively.

/>

With respect to use as benzoThe ultraviolet absorbing pigment (C) of the azole compound includes, for example: a compound represented by the following formula (U2-1), and the like.

Examples of the inorganic ultraviolet absorber include: zinc oxide, titanium oxide, cerium oxide, zirconium oxide, mica, kaolin, sericite, and the like.

[ optical Properties ]

The filter 10 preferably has the following characteristics (a-1) to (a-4).

The average transmittance of (a-1) at the wavelength of 440nm to 500nm at an incident angle of 0 DEG is 75% or more.

The average transmittance of (a-2) at a wavelength of 500nm to 600nm at an incident angle of 0 DEG is 75% or more.

(a-3) a difference between a wavelength on a short wavelength side and a wavelength on a long wavelength side when a transmittance in an infrared wavelength region at an incident angle of 0 DEG of light reaches 50% is 35nm or more.

The transmittance at 700nm at an incident angle of 0 DEG with respect to the light of (a-4) is 65% or less.

Transmittance is a value measured using an ultraviolet-visible near-infrared spectrophotometer. In the present specification, the average transmittance in a specific wavelength range means a value obtained by averaging the transmittance at all wavelengths in the wavelength range. In addition, in the case of measuring the transmittance by making light incident from a direction other than the direction orthogonal to the main surface of the subject in the measurement of the transmittance of light, the angle formed by the straight line indicating the direction in which the light is incident with respect to the line orthogonal to the main surface is referred to as the incident angle. Unless otherwise specified, the transmittance of light refers to a ratio at which light incident from a direction orthogonal to the main surface of the object passes straight through the inside of the object and is transmitted to the opposite side.

The filter 10 exhibits excellent near infrared ray shielding characteristics by having the characteristics (a-1) to (a-4) described above. Thus, the sensitivity of the solid-state imaging device can be improved.

The filters 40, 50, 60 having the second light absorbing layer 3 shown in fig. 4 to 6 preferably have the following characteristics (b-1) to (b-7).

(b-1) having a wavelength lambda at which the transmittance of light reaches 50% in the ultraviolet wavelength region in the range of 0 DEG to 50 DEG of the incident angle of light _UV50％ The wavelength lambda _UV50％ In the range of 350nm to 420 nm.

(b-2) the wavelength lambda at the incident angle of 0 DEG to the light _UV50％ Said wavelength lambda at an angle of incidence of 30 DEG to the light _UV50％ The difference is 10nm or less.

(b-3) the average transmittance of the light having a wavelength of 440nm to 500nm at an incident angle of 0 DEG is 75% or more.

(b-4) the average transmittance of the light having a wavelength of 500nm to 600nm at an incident angle of 0 DEG is 75% or more.

(b-5) having a wavelength lambda at which the transmittance of light in the infrared wavelength region reaches 50% _IR50％ The wavelength lambda at the incidence angle of light 0 DEG _IR50％ Said wavelength lambda at an angle of incidence of 30 DEG to the light _IR50％ The difference is 10nm or less.

(b-6) the average transmittance of the light having a wavelength of 750nm to 1000nm at an incident angle of 0 DEG is 90% or less.

(b-7) having a wavelength lambda at which the transmittance of light in the infrared wavelength region reaches 20% _IR20％ The wavelength lambda at the incidence angle of light 0 DEG _IR20％ Said wavelength lambda at an angle of incidence of 30 DEG to the light _IR20％ The difference is 5nm or less.

The optical filters 40, 50, 60 having the second light absorbing layer 3 can exhibit excellent near infrared ray shielding characteristics and ultraviolet ray shielding characteristics by having the characteristics (b-1) to (b-7) described above. Therefore, the color reproducibility of the solid-state imaging device can be improved, and flare, ghost, which is noise at the time of imaging, can be suppressed.

(modification)

A modification of the filter 10 will be described with reference to fig. 2 to 6. Fig. 2 is a schematic cross-sectional view of a first modification of the filter according to the embodiment of the present invention. Fig. 3 is a schematic cross-sectional view of a second modification of the filter according to the embodiment of the present invention. Fig. 4 is a schematic cross-sectional view of a third modification of the filter according to the embodiment of the present invention. Fig. 5 is a schematic cross-sectional view of a fourth modification of the filter according to the embodiment of the present invention. Fig. 6 is a schematic cross-sectional view of a fifth modification of the filter according to the embodiment of the present invention.

As shown in fig. 2, the first light absorbing layer 2 may have an inorganic layer 21 containing an inorganic material (B) and a pigment layer 22 containing a near infrared ray absorbing pigment (a). The interface between the inorganic layer 21 and the pigment layer 22 may be a clear interface not including the other, or may be a portion where the inorganic material (B) and the near infrared absorbing pigment (a) are mixed. In fig. 2, an example is shown in which the transparent base material 1, the inorganic layer 21, and the pigment layer 22 are laminated in this order, but the transparent base material 1, the pigment layer 22, and the inorganic layer 21 may be laminated in this order. As shown in fig. 3, a plurality of inorganic layers 21 and a plurality of pigment layers 22 may be alternately laminated. In the example shown in fig. 3, the inorganic layers 21 and the pigment layers 22 may be alternately laminated in the reverse order.

As shown in fig. 4, the filter 40 may have the second light absorbing layer 3 on one main surface (first main surface) side of the transparent substrate 1. In the example shown in fig. 4, the transparent substrate 1, the first light absorbing layer 2, and the second light absorbing layer 3 are laminated in this order, but as shown in fig. 5, the transparent substrate 1, the second light absorbing layer 3, and the first light absorbing layer 2 may be laminated in this order in the filter 50. As shown in fig. 6, the filter 60 may be provided with a first light absorbing layer on the first main surface side of the transparent substrate 1 and a second light absorbing layer 3 on the second main surface side of the transparent substrate 1.

The second light absorbing layer 3 has an ultraviolet absorbing pigment (C) having a maximum absorption wavelength in the range of 300nm to 430nm and a matrix material. Specifically, as the ultraviolet absorbing pigment (C), the same ultraviolet absorbing pigment (C) as in the case of the filter 10 shown in fig. 1 described above can be applied.

Lambda of ultraviolet light absorbing pigment (C) _max The detection can be performed by using an absorption curve measured by, for example, an ultraviolet-visible near-infrared spectrophotometer (model: V770, manufactured by Japanese spectroscopy Co., ltd.) using a solution obtained by dissolving the ultraviolet-absorbing dye (C) in methylene chloride.

The ultraviolet absorbing pigment (C) has a maximum absorption wavelength in a wavelength range of 300nm to 430nm, and thus can impart an excellent ability to absorb light in an ultraviolet wavelength range (300 nm to 430 nm) to the filter 10.

The matrix material may be an inorganic material or a resin. Specifically, the inorganic material (B) similar to the case of the filter 10 shown in fig. 1 described above can be applied as the inorganic material.

The resin preferably has a refractive index of 1.45 or more. The refractive index is more preferably 1.5 or more, particularly preferably 1.6 or more. The upper limit of the refractive index of the resin is not particularly limited, but is preferably about 1.72 in view of easiness of obtaining and the like.

As the resin, specifically, there may be mentioned: acrylic resins, epoxy resins, alkene-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. One of these resins may be used alone, or two or more of these resins may be used in combination. In the case of using a resin having a refractive index of 1.45 or more, one of these resins may be used alone or two or more of these resins may be used in combination as long as the refractive index is 1.45 or more as a whole.

Among the resins, polyimide resins, polyester resins, and polycarbonate resins are preferable from the viewpoint of high solubility of the ultraviolet absorbing pigment (C) and high glass transition temperature, and from the viewpoint of suppressing thermal movement of the ultraviolet absorbing pigment (C) and improving heat resistance.

The filters 10, 20, 30, 40, 50, 60 of the present embodiment may be provided with a protective layer on the surface (surface in contact with the atmosphere) of the first light absorbing layer 2 or the second light absorbing layer 3. In the example shown in fig. 6, a protective layer may be provided on both the surface of the first light absorbing layer 2 and the surface of the second light absorbing layer 3. By providing the protective layer on the surface of the first light absorbing layer 2 or the second light absorbing layer 3, light and moisture reaching these light absorbing layers at specific wavelengths can be shielded, and thus the light resistance of the filter can be improved.

The protective layer is not particularly limited, and may be composed of an antireflection film, a reflection film that reflects light in a specific wavelength range, a selective wavelength shielding film that controls transmission and shielding of light in a specific wavelength range, a radiation shielding film that shields radiation such as α rays, and the like. The protective layer preferably has at least one of optical characteristics that suppress reflection of visible light, optical characteristics that reflect ultraviolet light, and optical characteristics that reflect infrared light. Specifically, for example, at least one of a visible light antireflection film that suppresses reflection of visible light, an ultraviolet reflection film that reflects ultraviolet light, and an infrared reflection film that reflects infrared light may be provided. Examples of the protective layer having such optical characteristics include: a dielectric multilayer film is obtained by laminating two or more dielectric films having different refractive indices.

Examples of the material constituting the protective layer include: silica, alumina, composite materials containing these as a main component, and the like. The protective layer provided on the surface of the first light absorbing layer preferably contains the same material as the inorganic material (B). In addition, the protective layer provided on the surface of the second light absorbing layer preferably contains the same material as the matrix material. By setting the above, the adhesion between each light absorbing layer and the protective layer is high, and peeling of both layers is less likely to occur. The protective layer may be one layer or may be a plurality of layers made of different materials.

The film thickness of the protective layer is preferably 0.01 μm to 10 μm, more preferably 0.1 μm to 5 μm, and is preferably thin from the viewpoint of thickness reduction of the filter. When the protective layer is formed of a plurality of layers, the total physical film thickness of the plurality of layers is used as the film thickness of the protective layer.

(manufacturing method)

As for the method of manufacturing the optical filter 10, for example, a vacuum vapor deposition method is used, and the first light absorbing layer 2 is formed on the transparent substrate 1 by simultaneously heating the near infrared ray absorbing dye (a) by resistance heating and the inorganic material (B) by Electron Beam (EB). In the case of the filter 10 having the first light absorbing layer 2 containing the near infrared ray absorbing dye (a) and the ultraviolet ray absorbing dye (C), for example, the near infrared ray absorbing dye (a) and the ultraviolet ray absorbing dye (C) are mixed and then heated by resistance heating. By using the vacuum vapor deposition method, the concentration of the near infrared ray absorbing dye (a) contained in the first light absorbing layer 2 can be increased as compared with the wet film forming process, and thus a filter having more excellent near infrared ray shielding characteristics can be obtained.

In the case of the filter 20 shown in fig. 2, for example, an inorganic material (B) is heated by Electron Beam (EB) to form an inorganic layer 21 on the transparent substrate 1, and then a near infrared ray absorbing pigment (a) is heated by resistance heating to form a pigment layer 22 on the inorganic layer 21. In the case of the filter 30 shown in fig. 3, the above-described operation is repeated, thereby forming a multilayer laminated structure.

The above-described vacuum vapor deposition method can be applied to the filters 40, 50, 60 shown in fig. 4 to 6, for example. As a method for producing the second light-absorbing layer 3, when an inorganic material is used as a matrix material, for example, a vacuum vapor deposition method can be used, and when a resin is used, for example, the following method can be used. Can be manufactured by: the ultraviolet-absorbing pigment (C) and the resin (B) are dispersed in a solvent to be dissolved, and the coating liquid thus prepared is applied on the transparent substrate 1 or the first light-absorbing layer 2, dried, and further cured as needed.

In the case of providing the protective layer, a vacuum film forming process such as a CVD method, a sputtering method, a vacuum vapor deposition method, or the like can be used for forming the protective layer; wet film forming processes such as spray coating and dip coating.

The embodiments of the present invention have been described above by taking the filters 10, 20, 30, 40, 50, 60 shown in fig. 1 to 6 as examples, but the filters are not limited thereto. The configuration can be changed as needed and within the limits not departing from the gist of the present invention. For example, any one of the filters may be provided with a reflective film that reflects light in a specific wavelength range and a selective wavelength shielding film that controls transmission and shielding of light in the specific wavelength range.

The filters 10, 20, 30, 40, 50, 60 can be used as imaging devices such as smart phone-mounted cameras, digital still cameras, digital video cameras, monitoring cameras, in-vehicle cameras, and network cameras, near infrared filters for automatic exposure meters, near infrared filters for PDPs, and the like. The filter can be used as a filter having two pass bands of wavelengths of visible light and near infrared light (for example, light having wavelengths of only 850nm and 940 nm) and cut off light having wavelengths other than those pass bands. The optical filter of the present invention is suitable for use in solid-state imaging devices such as smart phone-mounted cameras, digital still cameras, digital video cameras, surveillance cameras, in-vehicle cameras, and network cameras, and is disposed between an imaging lens and a solid-state imaging element, for example.

Examples

Next, an embodiment of the present invention will be described. The present invention is not limited to the embodiments and examples described below. In the following description, examples 1 to 3 and 9 are examples, and example 4 is a comparative example. Examples 5 to 8 are reference examples.

Filters of examples 1 to 9 having the structures shown in tables 1 and 2 were produced. Examples 1 to 9 will be described in detail below.

Example 1

Longitudinal direction was used: 50mm, transverse: 50mm, thickness: a0.3 mm flat glass plate (D263, manufactured by Schottky Co.) was used as the transparent substrate. Using magnesium fluoride (MgF) ₂ ) As a matrix material, compound (F11-7) (molecular weight 766.54, maximum absorption wavelength in methylene chloride solution 706nm, manufactured by tokyo chemical Co., ltd., product name: UVITEX OB) as a near infrared ray absorbing dye, a film was formed on a glass plate by a vacuum deposition apparatus so that both became mixed, thereby forming a light absorbing layer. Compound (F11-7) was synthesized based on International publication (WO 2014/088063). The thickness of the light absorption layer is properly regulated to be between 200nm and 700 nm. On the surface of the obtained light absorption layer, silicon oxide (SiO ₂ ) The filter of example 1 was obtained by forming a protective layer by a vacuum deposition apparatus so that the film thickness was 100nm or more.

Example 2

In example 1, siO was used ₂ A filter of example 2 was obtained in the same manner as in example 1 except that the substrate was used.

Example 3

A filter of example 3 was obtained in the same manner as in example 1 except that compound (F11-8) (molecular weight 850.63, maximum absorption wavelength in methylene chloride solution: 714 nm) was used as the near infrared ray absorbing dye in example 1.

Example 4

In a solution obtained by dissolving polyimide (trade name: C-3G30G manufactured by Mitsubishi gas chemical corporation) in an organic solvent, a compound (F11-7) which is a near infrared ray absorbing pigment was mixed in a ratio of 4.5 parts by mass to 100 parts by mass of polyimide and the compound (F11-7), and then stirred and dissolved at room temperature, thereby obtaining a coating liquid. The obtained coating liquid was coated in the longitudinal direction as a transparent substrate using a spin coater: 50mm, transverse: 50mm, thickness: a0.21 mm flat glass plate (D263; manufactured by Schottky Co., ltd.) was heated and dried to remove the organic solvent, thereby forming a light-absorbing layer having a film thickness of 1.11. Mu.m, and the optical filter of example 4 was obtained.

Example 5

In example 1, siO was used ₂ A filter of example 5 was obtained in the same manner as in example 1, except that the compound (F11-8) (molecular weight 850.63, maximum absorption wavelength in methylene chloride solution: 714 nm) was used as the substrate material as the near infrared ray absorbing dye.

Example 6

Longitudinal direction was used: 50mm, transverse: 50mm, thickness: a0.3 mm flat glass plate (D263, manufactured by Schottky Co.) was used as the transparent base material, and alumina (Al ₂ O ₃ ) As a substrate material, an inorganic layer having a film thickness of 10nm was formed on a glass plate by a vacuum deposition method. Next, on the surface of the obtained inorganic layer, a compound (F11-7) (molecular weight 766.54, maximum absorption wavelength in methylene chloride solution: 706 nm) was used as a near infrared ray absorbing dye, followed by vacuum evaporationThe plating method forms a pigment layer with a film thickness of 13nm to 20 nm. The formation of the inorganic layer was repeated 6 times, and the formation of the pigment layer was repeated 5 times, and the inorganic layer and the pigment layer were alternately laminated one by one, thereby forming a light absorbing layer including 11 total layers. The outermost surface of the light absorbing layer is formed by using alumina (Al ₂ O ₃ ) An inorganic layer having a film thickness of 10nm and formed by vacuum vapor deposition, the inorganic layer being a protective layer. The filter of example 6 was obtained in this manner.

Example 7

In example 6, siO was used ₂ SiO as matrix material ₂ A filter of example 7 was obtained in the same manner as in example 6 except that the film thickness was 46nm to 53 nm. In example 7, the outermost surface of the light absorbing layer was formed using SiO ₂ An inorganic layer having a film thickness of 53nm and formed by vacuum vapor deposition, the inorganic layer being a protective layer.

Example 8

In example 1, siO was used ₂ A filter of example 8 was obtained in the same manner as in example 1 except that no protective layer was provided as the substrate material.

Example 9

In example 1, magnesium fluoride (MgF ₂ 100 nm) was performed in the same manner as in example 1, except that silicon oxide was used as a protective layer on the surface of the light absorbing layer, thereby obtaining a filter of example 9.

[ measurement of spectral transmittance ]

The obtained filters of examples 1 to 9 were subjected to measurement of transmittance at an incident angle of 0℃by using an ultraviolet-visible near infrared spectrophotometer (model: V770, manufactured by Japanese Spectrophotometer Co., ltd.), to obtain a spectral transmittance curve. Fig. 7 shows the spectral transmittance curve of the filter of example 1, fig. 8 shows the spectral transmittance curve of the filter of example 2, fig. 9 shows the spectral transmittance curve of the filter of example 3, fig. 10 shows the spectral transmittance curve of the filter of example 4, fig. 11 shows the spectral transmittance curve of the filter of example 5, fig. 12 shows the spectral transmittance curve of the filter of example 6, fig. 13 shows the spectral transmittance curve of the filter of example 7, fig. 14 shows the spectral transmittance curve of the filter of example 8, and fig. 15 shows the spectral transmittance curve of the filter of example 9. As shown in fig. 7 to 15, the filters of examples 1 to 9 were filters having low transmittance of light in the vicinity of 700nm and near infrared shielding characteristics.

[ evaluation of light resistance ]

The light resistance test was performed on the obtained filters of examples 1 to 4 and 9, and the light resistance was evaluated. In the light resistance test, the filter was irradiated with light under the following conditions using Super Xenon Weather Meter SX75 (manufactured by Wash tester Co., ltd.).

(irradiation conditions)

Wavelength: 300 nm-2450 nm

Temperature: 40 DEG C

Humidity: 50% RT

Cumulative light amount: 87.2 kw.h/m ²

After light irradiation, the transmittance at an incident angle of 0 ° was measured, and a spectral transmittance curve was obtained. Fig. 7 shows the spectral transmittance curves before and after the light resistance test of the filter of example 1, fig. 8 shows the spectral transmittance curves before and after the light resistance test of the filter of example 2, fig. 9 shows the spectral transmittance curves before and after the light resistance test of the filter of example 3, fig. 10 shows the spectral transmittance curves before and after the light resistance test of the filter of example 4, and fig. 15 shows the spectral transmittance curves before and after the light resistance test of the filter of example 9.

The minimum transmittance of light having a wavelength of 500nm to 800nm before and after irradiation was obtained from the spectral transmittance curve before and after irradiation, and the fluctuation was calculated by the following formula.

Minimum transmittance variation [% ] = (minimum transmittance of light having a wavelength of 500nm to 800nm before irradiation) - (minimum transmittance of light having a wavelength of 500nm to 800nm after irradiation)

In the evaluation of light resistance, a is shown in table 1 when the minimum transmittance variation amount [% ] is 10% or less, B is shown in table 1 when the minimum transmittance variation amount [% ] is more than 10%, and a is evaluated as being acceptable.

TABLE 1

TABLE 2

As shown in table 1, the filters of examples 1 to 3 and 9 using an inorganic material as a matrix material were found to have good light resistance. Since the matrix material is an inorganic material, the hydroxyl groups are smaller than those in the case where the matrix material is a resin, and photooxidation of the near infrared ray absorbing pigment (a) by light is suppressed.

Mode for the invention

The present invention includes the following means.

Mode 1 >

A filter comprising a transparent substrate having a first main surface and a first light-absorbing layer provided on the first main surface side of the transparent substrate,

the first light absorbing layer contains a near infrared ray absorbing pigment and an inorganic material,

the near infrared ray absorption pigment has a maximum absorption wavelength in a wavelength range of 650nm to 760nm, and the molecular weight of the near infrared ray absorption pigment is 2000 or less.

Mode 2 >

The filter according to mode 1, wherein the first light absorbing layer is formed by mixing the near infrared absorbing dye and the inorganic material.

Mode 3 >

The filter according to claim 2, wherein the concentration of the near infrared ray absorption dye is different in the orthogonal direction to the first main surface.

Mode 4 >

The filter according to mode 1, wherein the first light-absorbing layer has a pigment layer containing the near infrared ray-absorbing pigment and an inorganic layer containing the inorganic material.

Mode 5 >

The filter according to any one of claims 1 to 4, wherein the filter has the following characteristics.

Mode 6 >

The optical filter according to any one of embodiments 1 to 5, wherein the near infrared ray absorbing dye is selected from the group consisting of squaric acid At least one kind selected from the group consisting of salt compounds, phthalocyanine compounds and cyanine compounds. />

Mode 7 >

The optical filter according to mode 6, wherein the squaraine isThe salt compound has a structure represented by the following formula (F1),

wherein the symbols in formula (F1) are as follows: r is R ⁴ And R is ⁶ Each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an acyloxy group having 1 to 10 carbon atoms, or a C6 to 11 carbon atomsAryl group of (C), aralkyl group having 7 to 18 carbon atoms which may have a substituent and may have an oxygen atom between carbon atoms, -NR ⁷ R ⁸ (R ⁷ And R is ⁸ Each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, -C (=O) -R ⁹ (R ⁹ A hydrocarbon group of 1 to 25 carbon atoms which is a hydrogen atom, a halogen atom, a hydroxyl group, a hydrocarbon group which may have a substituent and may contain an unsaturated bond, an oxygen atom, a saturated or unsaturated ring structure between carbon atoms), or-NHR ¹⁰ or-SO ₂ -R ¹⁰ (R ¹⁰ Each of which is a hydrocarbon group having 1 to 25 carbon atoms and having a ring structure which may be unsaturated, oxygen atom, saturated or unsaturated, and which may be substituted with a halogen atom, hydroxyl group, carboxyl group, sulfo group or cyano group), or a group (R) represented by the following formula (S) ⁴¹ And R is ⁴² Independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms, and k is 2 or 3);

R ¹ and R is ² Can be linked to each other and form together with the nitrogen atom a five-or six-membered heterocyclic ring A, R ² And R is ⁵ Can be linked to each other and form together with the nitrogen atom a five-or six-membered heterocyclic ring B, and R ¹ And R is ³ May be linked to each other and form together with the nitrogen atom a five-or six-membered heterocyclic ring C.

Mode 8 >

The filter according to any one of modes 1 to 7, wherein the refractive index of the inorganic material at a wavelength of 500nm is 1.38 to 2.20.

Mode 9 >

The filter according to mode 8, wherein the inorganic material is at least one selected from the group consisting of silica, alumina, and magnesium fluoride.

Mode 10 >

The filter according to any one of claims 1 to 9, wherein a protective layer is provided on a surface of the first light absorbing layer.

Mode 11 >

The filter according to mode 10, wherein the protective layer provided on the surface of the first light-absorbing layer contains the same material as the inorganic material.

Mode 12 >

The filter according to any one of aspects 10 to 11, wherein the protective layer provided on the surface of the first light absorbing layer has at least one of optical characteristics that suppress reflection of visible light, optical characteristics that reflect ultraviolet light, and optical characteristics that reflect infrared light.

Mode 13 >

The optical filter according to any one of modes 1 to 12, wherein,

a second light absorbing layer is provided on the first main surface side of the transparent substrate,

the second light absorbing layer comprises an ultraviolet absorbing pigment and a matrix material,

the ultraviolet absorbing pigment has a maximum absorption wavelength in a wavelength range of 300nm to 430 nm.

Mode 14 >, mode

The filter according to mode 13, wherein the matrix material is any one selected from the group consisting of silica, alumina, magnesium fluoride, polyimide resin, polyester resin, and polycarbonate resin.

Mode 15 >

The optical filter according to any one of embodiments 13 to 14, wherein the ultraviolet absorbing pigment is selected from the group consisting of triazines, indoles, azomethines, benzotriazoles, merocyanines, and benzotriazolesAt least one kind of azole compound.

Mode 16 >

The filter according to claim 15, wherein the ultraviolet-absorbing dye comprises a merocyanine compound represented by the following formula (U1),

wherein the symbols in formula (U1) are as follows:

y represents R ⁶ And R is ⁷ A substituted methylene group, or an oxygen atom;

R ¹ Represents a monovalent hydrocarbon group having 1 to 12 carbon atoms which may have a substituent; r is R ² ～R ⁷ Each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms;

x represents any one of divalent groups represented by the following formulas (X1) to (X5) (wherein R ⁸ And R is ⁹ Each independently represents a monovalent hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, R ¹⁰ ～R ¹⁹ Each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms which may have a substituent).

Mode 17 >

The filter according to mode 16, wherein, in formula (U1), R ¹ 、R ⁸ And R is ⁹ Each independently is an alkyl group having 1 to 6 carbon atoms, a part of which may be substituted with a cycloalkyl group or a phenyl group, R ² ～R ⁷ And R is ¹⁰ ～R ¹⁹ Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

Mode 18 >

The filter according to mode 16, wherein, in formula (U1), R ¹ 、R ⁸ And R is ⁹ Each independently is an alkyl group having 1 to 6 carbon atoms, R ² ～R ⁷ And R is ¹⁰ ～R ¹⁹ Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

Mode 19 >

The filter according to mode 15, wherein the ultraviolet-absorbing pigment is benzoAzole compounds.

Mode 20 >

The filter according to any one of claims 13 to 19, wherein a protective layer is provided on a surface of the second light absorbing layer.

Mode 21 >

The filter according to claim 20, wherein the protective layer provided on the surface of the second light-absorbing layer contains the same material as the matrix material.

Mode 22 >, mode

The filter according to claim 20 or 21, wherein the protective layer provided on the surface of the second light absorbing layer has at least one of optical characteristics that suppress reflection of visible light, optical characteristics that reflect ultraviolet light, and optical characteristics that reflect infrared light.

Mode 23 >

The filter according to any one of claims 13 to 22, wherein the filter has the following characteristics.

The international application claims priority based on japanese patent application No. 2021-121013, filed on 7/21 of 2021, the entire contents of which are incorporated herein by reference.

Description of the reference numerals

1. Transparent substrate

2. First light absorption layer

21. Inorganic layer

22. Pigment layer

3. Second light absorption layer

10. 20, 30, 40, 50, 60 optical filters

Claims

1. A filter comprising a transparent substrate having a first main surface and a first light-absorbing layer provided on the first main surface side of the transparent substrate,

2. The filter according to claim 1, wherein the first light absorbing layer is formed by mixing the near infrared ray absorbing pigment and the inorganic material.

3. The filter according to claim 2, wherein the concentration of the near infrared ray absorption pigment is different in the orthogonal direction of the first main surface.

4. The filter according to claim 1, wherein the first light absorbing layer has a pigment layer containing the near infrared ray absorbing pigment and an inorganic layer containing the inorganic material.

5. The filter according to claim 2 or 4, wherein the filter has the following characteristics:

(a-1) an average transmittance of 75% or more at a wavelength of 440nm to 500nm at an incident angle of 0 DEG;

(a-2) an average transmittance of 75% or more at a wavelength of 500nm to 600nm at an incident angle of 0 DEG;

(a-3) a difference between a wavelength on a short wavelength side and a wavelength on a long wavelength side when a transmittance in an infrared wavelength region at an incident angle of 0 ° of light reaches 50% is 35nm or more;

6. The optical filter according to claim 1, wherein the near infrared absorbing dye is selected from the group consisting of squaraine At least one kind selected from the group consisting of salt compounds, phthalocyanine compounds and cyanine compounds.

7. The filter of claim 6, wherein the squaraine isThe salt compound has a structure represented by the following formula (F1),

wherein, the method comprises the following steps of(F1) The symbols in (a) are as follows: r is R ⁴ And R is ⁶ Each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an acyloxy group having 1 to 10 carbon atoms, an aryl group having 6 to 11 carbon atoms, an aralkyl group having 7 to 18 carbon atoms which may have a substituent and may have an oxygen atom between carbon atoms, -NR ⁷ R ⁸ (R ⁷ And R is ⁸ Each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, -C (=O) -R ⁹ (R ⁹ A hydrocarbon group of 1 to 25 carbon atoms which is a hydrogen atom, a halogen atom, a hydroxyl group, a hydrocarbon group which may have a substituent and may contain an unsaturated bond, an oxygen atom, a saturated or unsaturated ring structure between carbon atoms), or-NHR ¹⁰ or-SO ₂ -R ¹⁰ (R ¹⁰ Each of which is a hydrocarbon group having 1 to 25 carbon atoms and having a ring structure which may be unsaturated, oxygen atom, saturated or unsaturated, and which may be substituted with a halogen atom, hydroxyl group, carboxyl group, sulfo group or cyano group), or a group (R) represented by the following formula (S) ⁴¹ And R is ⁴² Independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms; k is 2 or 3);

8. The filter according to claim 7, wherein the refractive index of the inorganic material is 1.38 to 2.20 at a wavelength of 500 nm.

9. The filter according to claim 8, wherein the inorganic material is at least one selected from the group consisting of silica, alumina, and magnesium fluoride.

10. The filter according to claim 9, wherein a protective layer is provided on a surface of the first light absorbing layer.

11. The filter according to claim 10, wherein the protective layer provided on the surface of the first light absorbing layer contains the same material as the inorganic material.

12. The filter according to claim 11, wherein the protective layer provided on the surface of the first light absorbing layer has at least one of optical characteristics that suppress reflection of visible light, optical characteristics that reflect ultraviolet light, and optical characteristics that reflect infrared light.

13. The filter according to claim 12, wherein,

14. The filter according to claim 13, wherein the matrix material is any one selected from the group consisting of silica, alumina, magnesium fluoride, polyimide resin, polyester resin, and polycarbonate resin.

15. The optical filter according to claim 14, wherein the ultraviolet absorbing pigment is selected from the group consisting of triazines, indoles, azomethines, benzotriazoles, merocyanines and benzotriazolesAt least one kind of azole compound.

16. The optical filter according to claim 15, wherein the ultraviolet absorbing pigment comprises a merocyanine compound represented by the following formula (U1),

wherein the symbols in formula (U1) are as follows:

x represents any one of divalent groups represented by the following formulas (X1) to (X5) (wherein R ⁸ And R is ⁹ Each independently represents a monovalent hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, R ¹⁰ ～R ¹⁹ Each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms which may have a substituent);

17. the filter according to claim 16, wherein in formula (U1), R ¹ 、R ⁸ And R is ⁹ Each independently is an alkyl group having 1 to 6 carbon atoms, a part of which may be substituted with a cycloalkyl group or a phenyl group, R ² ～R ⁷ And R is ¹⁰ ～R ¹⁹ Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

18. According to claim 16Wherein, in the formula (U1), R ¹ 、R ⁸ And R is ⁹ Each independently is an alkyl group having 1 to 6 carbon atoms, R ² ～R ⁷ And R is ¹⁰ ～R ¹⁹ Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

19. The filter of claim 15 wherein the ultraviolet absorbing pigment is a benzoAzole compounds.

20. The filter according to claim 19, wherein a protective layer is provided on a surface of the second light absorbing layer.

21. The filter according to claim 20, wherein the protective layer provided on the surface of the second light absorbing layer contains the same material as the matrix material.

22. The filter according to claim 21, wherein the protective layer provided on the surface of the second light absorbing layer has at least one of optical characteristics that suppress reflection of visible light, optical characteristics that reflect ultraviolet light, and optical characteristics that reflect infrared light.

23. The filter of claim 13, wherein the filter has the following characteristics:

(b-1) having a wavelength lambda at which the transmittance of light reaches 50% in the ultraviolet wavelength region in the range of 0 DEG to 50 DEG of the incident angle of light _UV50％ The wavelength lambda _UV50％ Is in the range of 350nm to 420 nm;

(b-2) the wavelength lambda at the incident angle of 0 DEG to the light _UV50％ Said wavelength lambda at an angle of incidence of 30 DEG to the light _UV50％ The difference is 10nm or less;

(b-3) an average transmittance of 75% or more at a wavelength of 440nm to 500nm at an incident angle of 0 DEG;

(b-4) an average transmittance of 75% or more at a wavelength of 500nm to 600nm at an incident angle of 0 DEG;

(b-5) having a wavelength lambda at which the transmittance of light in the infrared wavelength region reaches 50% _IR50％ The wavelength lambda at the incidence angle of light 0 DEG _IR50％ Said wavelength lambda at an angle of incidence of 30 DEG to the light _IR50％ The difference is 10nm or less;

(b-6) an average transmittance of 90% or less at a wavelength of 750nm to 1000nm at an incident angle of 0 DEG;