WO2014192715A1 - Optical filter, and device using said filter - Google Patents

Abstract

[Problem] To provide an optical filter with which improvements are made with respect to problems of conventional optical filters such as near infrared cut-off filters, which has a broad angular field of view even in the vicinity of a lower end of a transmission wavelength range, and which exhibits excellent visible light transmittance and excellent infrared-beam cut-off properties. [Solution] Provided is an optical filter provided with: a transparent resin substrate including a near-infrared absorption pigment; and a near-infrared reflective film formed upon at least one surface of the substrate. The optical filter satisfies conditions (A) to (C): (A) that the average transmittance of the filter measured from an orthogonal direction be at least 75% for wavelengths in the range 430-580 nm; (B) that the average transmittance of the filter measured from the orthogonal direction be not more than 20% for wavelengths in the range 800-1000 nm; and (C) that the absolute value of the difference between the value (Za) of the longest wavelength at which the transmittance of the filter measured from the orthogonal direction is 10% for wavelengths in the range 560-800 nm, and the value (Zb) of the longest wavelength at which the transmittance of the filter measured from an angle of 30˚ with respect to the orthogonal direction is 10% for wavelengths in the range 560-800 nm, be less than 25 nm.

Description

Optical filter and apparatus using the filter

The present invention relates to an optical filter and an apparatus using the filter. Specifically, it has a wide viewing angle in the “light transmission wavelength range close to the light cut wavelength range” (hereinafter also referred to as “near the bottom of the transmission wavelength range”) in the near infrared wavelength range, and in particular, a CCD, a CMOS image sensor, etc. The present invention relates to an optical filter that can be suitably used as a visual sensitivity correction filter for a solid-state imaging device, and a solid-state imaging device and a camera module using the filter.

In a solid-state imaging device such as a video camera, a digital still camera, and a mobile phone with a camera function, a CCD or CMOS image sensor which is a solid-state imaging device for color images is used. These solid-state imaging devices use a silicon photodiode having sensitivity to near infrared rays in the light receiving portion. These solid-state image sensors need to perform visibility correction to make them look natural when viewed by the human eye, and are optical filters that selectively transmit or cut light in a specific wavelength region (for example, near-infrared cut) Filter) is often used.

As such a near-infrared cut filter, those manufactured by various methods are conventionally used. For example, Patent Document 1 describes a near-infrared cut filter using a substrate made of a transparent resin and containing a near-infrared absorbing dye in the transparent resin. However, the near-infrared cut filter described in Patent Document 1 may not always have sufficient near-infrared absorption characteristics.

Further, the present applicant has proposed a near-infrared cut filter having a norbornene-based resin substrate and a near-infrared reflective film in Patent Document 2. The near-infrared cut filter described in Patent Document 2 is excellent in near-infrared cut characteristics, moisture absorption resistance and impact resistance, but cannot take a wide viewing angle.

As a result of intensive studies, the present applicant uses a transparent resin substrate containing a near-infrared absorbing dye having an absorption maximum at a specific wavelength, so that the light transmission wavelength region and the light cut wavelength region can be changed even when the incident angle is changed. We found that a near-infrared cut filter with little change in optical properties near the middle (transmittance 50%) was obtained, and proposed a near-infrared cut filter with a wide viewing angle and high visible light transmittance in Patent Document 3. ing.

Japanese Patent Laid-Open No. 6-200113 JP 2005-338395 A JP 2011-100084 A

In recent years, the image quality level required for camera images has become very high even in mobile devices. According to the study by the present inventors, there has been a case where it is not possible to satisfy the demand for high image quality such as color reproducibility only by improving the viewing angle in the vicinity of the conventional wavelength of 50% transmittance.

An object of the present invention is to improve the problems of conventional optical filters such as a near-infrared cut filter, have a wide viewing angle near the bottom of the transmission wavelength region, and have a visible light transmittance and a red color. An object of the present invention is to provide an optical filter excellent in external light cut characteristics and an apparatus using the filter.

As a result of intensive studies, the present inventors have found that the above problems can be solved by an optical filter that satisfies the following requirements (A) to (C), and have completed the present invention. Examples of embodiments of the present invention are shown below.

[1] An optical system having a transparent resin substrate containing a near-infrared absorbing dye and a near-infrared reflective film formed on at least one surface of the substrate and satisfying the following requirements (A) to (C) filter:
(A) In the wavelength range of 430 to 580 nm, the average value of the transmittance when measured from the vertical direction of the optical filter is 75% or more.
(B) In the wavelength range of 800 to 1000 nm, the average value of transmittance when measured from the vertical direction of the optical filter is 20% or less.
(C) In the wavelength range of 560 to 800 nm, the longest wavelength value (Za) at which the transmittance when measured from the vertical direction of the optical filter is 10%, and an angle of 30 ° with respect to the vertical direction of the optical filter The absolute value | Za−Zb | of the difference from the longest wavelength value (Zb) at which the transmittance is 10% when measured from is less than 25 nm.

[2] The optical filter as described in [1] above, wherein the absorption maximum wavelength of the transparent resin substrate containing a near-infrared absorbing dye is 600 to 800 nm.
[3] The optical filter according to [1] or [2], wherein a transmittance at an absorption maximum wavelength when measured from a vertical direction of a resin substrate containing a near-infrared absorbing dye is 10% or less.

[4] The transparent resin constituting the transparent resin substrate is a cyclic olefin resin, aromatic polyether resin, polyimide resin, fluorene polycarbonate resin, fluorene polyester resin, polycarbonate resin, polyamide resin, poly Allylate resin, polysulfone resin, polyethersulfone resin, polyparaphenylene resin, polyamideimide resin, polyethylene naphthalate resin, fluorinated aromatic polymer resin, (modified) acrylic resin, epoxy resin 4. The optical filter according to any one of [1] to [3], which is at least one resin selected from the group consisting of allyl ester resins and silsesquioxane resins.

[5] The transparent resin substrate is at least one selected from the group consisting of squarylium compounds, cyanine compounds, phthalocyanine compounds, naphthalocyanine compounds, croconium compounds, dithiol compounds, diimonium compounds and porphyrin compounds. 6. The optical filter according to any one of [1] to [4], which contains a kind of near-infrared absorbing dye.

[6] The said near-infrared absorption pigment | dye contains at least 1 sort (s) chosen from the group which consists of the squarylium type compound represented by the squarylium type compound represented by the formula (I) mentioned later, and the formula (II) mentioned later [ The optical filter according to any one of [1] to [5].

[7] The optical filter according to any one of [1] to [6], including the transparent resin substrate and the near-infrared reflective film formed on both surfaces of the substrate.
[8] The optical filter according to any one of [1] to [7], which is for a solid-state imaging device.

[9] A solid-state imaging device comprising the optical filter according to any one of [1] to [7].
[10] A camera module comprising the optical filter according to any one of [1] to [7].

According to the present invention, it is possible to provide an optical filter that has a wide viewing angle even near the bottom of the transmission wavelength region and is excellent in visible light transmittance and infrared ray cut characteristics. When such an optical filter is used for a solid-state imaging device, it is possible to obtain a camera image with excellent image reproducibility and excellent color reproducibility with respect to light incident from an oblique direction as compared with a conventional optical filter.

FIG. 1A is a schematic cross-sectional view showing an example of a conventional camera module. FIG. 1B is a schematic cross-sectional view showing an example of a camera module when the optical filter 6 ′ of the present invention is used. FIG. 2A is a schematic diagram illustrating a method for measuring the transmittance when measured from the vertical direction of the optical filter. FIG. 2B is a schematic diagram illustrating a method of measuring the transmittance when measured from an angle of 30 ° with respect to the vertical direction of the optical filter. FIG. 3 is a schematic view showing an example of characteristics of a near-infrared reflective film formed on a transparent resin substrate containing a near-infrared absorbing dye.

Hereinafter, the present invention will be specifically described.
[Optical filter]
The optical filter of the present invention has a transparent resin substrate and a near-infrared reflective film formed on at least one surface of the substrate. When the near-infrared reflective film is provided on both surfaces of the transparent resin substrate, the warp of the optical filter can be further reduced as compared with the case where the near-infrared reflective film is provided only on one side.

The optical filter of the present invention satisfies the following requirements (A) to (C).
(A) In a wavelength range of 430 to 580 nm, the average value of transmittance when measured from the vertical direction of the optical filter is 75% or more. This average value is preferably 78% or more, more preferably 80% or more.

In the present invention, for example, an optical filter having a high transmittance in such a wavelength region of 430 to 580 nm can be obtained by using a transparent resin described later and an absorbent having no absorption maximum wavelength in the wavelength region. it can.

(B) In the wavelength range of 800 to 1000 nm, the average value of the transmittance when measured from the vertical direction of the optical filter is 20% or less. This average value is preferably 15% or less, more preferably 10% or less.
In the present invention, an optical filter having a sufficiently low transmittance in such a wavelength region of 800 to 1000 nm is obtained by providing a predetermined near-infrared reflective film having high near-infrared reflectivity on a transparent resin substrate. be able to.

(C) In the wavelength range of 560 to 800 nm, the longest wavelength value (Za) at which the transmittance when measured from the vertical direction of the optical filter is 10%, and an angle of 30 ° with respect to the vertical direction of the optical filter The absolute value | Za−Zb | of the difference from the longest wavelength value (Zb) at which the transmittance when measured from the above is 10% is less than 25 nm. This absolute value | Za−Zb | is preferably 22 nm or less, more preferably 18 nm or less, and particularly preferably 15 nm or less.

In the present invention, an optical filter in which the absolute value of the difference in wavelength that achieves a predetermined transmittance falls within the above range by combining light absorption by a near-infrared absorbing dye and light reflection by a near-infrared reflecting film in an optimal balance. Obtainable.

More specifically, the transmittance at the absorption maximum wavelength when measured from the vertical direction of a resin substrate containing a near infrared absorbing dye is preferably 10% or less, more preferably 8% or less, and particularly preferably 6% or less. So that there is absorption by the near-infrared absorbing dye contained in the resin substrate from the wavelength range cut by the near-infrared reflective film to the wavelength range that passes through the near-infrared reflective film. It is desirable to design a near-infrared reflective film. Here, a part of the absorption wavelength region of the near-infrared absorbing dye and the wavelength region cut by the near-infrared reflecting film overlap, so that the transmittance in the wavelength region of 560 to 800 nm is obtained in the final optical filter. The wavelength that will be 10% will be determined.

Thus, when the absolute value | Za−Zb | is in the above-mentioned range in the wavelength range of 560 to 800 nm, the optical property has a small incident angle dependency near the bottom of the transmission wavelength range, and has excellent color reproducibility. An optical filter with a wide angle can be obtained, and in particular, when the filter is used in a lens unit such as a camera module, a low-profile lens unit can be realized.

In the present invention, as described above, for example, a transparent resin substrate containing a near-infrared absorbing dye having absorption in a specific wavelength region is used, and the characteristics of the near-infrared reflecting film are controlled, thereby satisfying the requirement (A). An optical filter satisfying all of (C) with a good balance can be obtained. Since the optical filter of the present invention satisfies all the requirements (A) to (C), a satisfactory high image quality can be obtained particularly when used in a solid-state imaging device application as compared with the conventional optical filter.

It is preferable that the optical filter of the present invention further satisfies the following requirement (D).
(D) The haze value (JIS K7105 method) is 2.0% or less. This haze value is more preferably 1.5% or less, and particularly preferably 1.0% or less. When the haze value is within this range, not only a clear camera image can be obtained when the optical filter of the present invention is used for a solid-state imaging device, but also flare and ghost when a light source is photographed particularly in dark conditions. Since it can reduce, it is preferable.

[Transparent resin substrate]
The transparent resin substrate (hereinafter also referred to as “resin substrate”) constituting the optical filter of the present invention contains a transparent resin and a near-infrared absorbing dye, and preferably has an absorption maximum in the wavelength range of 600 to 800 nm. is there. If the absorption maximum wavelength of the substrate is within this range, the substrate can selectively and efficiently cut near infrared rays.

Further, as described above, the resin substrate preferably has a transmittance of 10% or less, more preferably 8% or less, when measured from the vertical direction of the resin substrate at the absorption maximum wavelength. Particularly preferably, it is 6% or less.

The resin substrate may be a single layer or multiple layers.
The thickness of the resin substrate can be appropriately selected according to the desired application, and is not particularly limited. However, it is preferable to adjust the substrate so that the incident angle dependency is improved as described above, and more preferably. Is 30 to 250 μm, more preferably 40 to 200 μm, particularly preferably 50 to 150 μm.

When the thickness of the resin substrate is within the above range, the optical filter using the substrate can be reduced in size and weight, and can be suitably used for various applications such as a solid-state imaging device. In particular, when the filter is used in a lens unit such as a camera module, the height of the lens unit can be reduced.

<Transparent resin>
The resin substrate can be formed using a transparent resin.
The transparent resin is not particularly limited as long as it does not impair the effects of the present invention. For example, it ensures thermal stability and moldability to a film, and dielectrics are formed by high-temperature deposition performed at a deposition temperature of 100 ° C. or higher. For example, a resin having a glass transition temperature (Tg) of preferably 110 to 380.degree. C., more preferably 110 to 370.degree. C., and still more preferably 120 to 360.degree. Further, it is particularly preferable that the glass transition temperature of the resin is 140 ° C. or higher because a film capable of depositing a dielectric multilayer film at a higher temperature can be obtained.

As the transparent resin, when a resin plate made of the resin having a thickness of 0.1 mm is formed, the total light transmittance (JIS K7105) of the resin plate is preferably 75 to 95%, more preferably 78 to 95. %, Particularly preferably 80 to 95% of the resin can be used. If a resin having a total light transmittance in such a range is used, the resulting substrate exhibits good transparency as an optical film.

The weight average molecular weight (Mw) in terms of polystyrene measured by a gel permeation chromatography (GPC) method of the transparent resin is usually 15,000 to 350,000, preferably 30,000 to 250,000; The average molecular weight (Mn) is usually 10,000 to 150,000, preferably 20,000 to 100,000.

Examples of the transparent resin include cyclic olefin resins, aromatic polyether resins, polyimide resins, fluorene polycarbonate resins, fluorene polyester resins, polycarbonate resins, polyamide (aramid) resins, polyarylate resins, polysulfones. Resin, polyethersulfone resin, polyparaphenylene resin, polyamideimide resin, polyethylene naphthalate (PEN) resin, fluorinated aromatic polymer resin, (modified) acrylic resin, epoxy resin, allyl Examples include ester resins and silsesquioxane resins.

(1) Cyclic olefin-based resin The cyclic olefin-based resin is at least one selected from the group consisting of a monomer represented by the following formula (X ₀ ) and a monomer represented by the following formula (Y ₀ ). A resin obtained from these monomers and a resin obtained by hydrogenating the resin are preferred.

In the formula (X ₀ ), R ^x1 to R ^x4 each independently represents an atom or group selected from the following (i ′) to (ix ′), and k ^x , ^mx and p ^x are each independently 0 Or represents a positive integer.
(I ′) a hydrogen atom (ii ′) a halogen atom (iii ′) a trialkylsilyl group (iv ′) a substituted or unsubstituted carbon atom having a linking group containing an oxygen atom, a sulfur atom, a nitrogen atom or a silicon atom 30 to 30 hydrocarbon group (v ′) substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms (vi ′) polar group (excluding (iv ′))
(Vii ′) an alkylidene group formed by bonding R ^x1 and R ^x2 or R ^x3 and R ^x4 to each other (provided that R ^x1 to R ^x4 not involved in the bonding are each independently (It represents an atom or group selected from (i ′) to (vi ′).)
(Viii ′) a monocyclic or polycyclic hydrocarbon ring or heterocyclic ring formed by combining R ^x1 and R ^x2 or R ^x3 and R ^x4 with each other (provided that R does not participate in the bonding) ^x1 to R ^x4 each independently represents an atom or group selected from (i ′) to (vi ′).
(Ix ′) A monocyclic hydrocarbon ring or heterocycle formed by bonding R ^x2 and R ^x3 to each other (provided that R ^x1 and R ^x4 not involved in the bonding are each independently the above (i Represents an atom or group selected from ') to (vi').

In the formula (Y ₀ ), R ^y1 and R ^y2 each independently represents an atom or group selected from the above (i ′) to (vi ′), or R ^y1 and R ^y2 are bonded to each other formed monocyclic or polycyclic alicyclic hydrocarbon, an aromatic hydrocarbon or heterocyclic, k ^y and p ^y are each independently 0 or a positive integer.

(2) Aromatic polyether-based resin The aromatic polyether-based resin is at least one selected from the group consisting of a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2). It preferably has a structural unit.

In formula (1), R ¹ to R ⁴ each independently represents a monovalent organic group having 1 to 12 carbon atoms, and a to d each independently represent an integer of 0 to 4.

Wherein ^{(2), R 1 ~ R} 4 and a ~ d are the same as R ¹ ~ R ⁴ and a ~ d of each in independently on the formula (1), Y a single bond, -SO ₂ -Or> C = O, R ⁷ and R ⁸ each independently represent a halogen atom, a monovalent organic group having 1 to 12 carbon atoms or a nitro group, and g and h each independently represent 0 to 4 And m represents 0 or 1. However, when m is 0, R ⁷ is not a cyano group.

The aromatic polyether resin further has at least one structural unit selected from the group consisting of a structural unit represented by the following formula (3) and a structural unit represented by the following formula (4). Is preferred.

In the formula (3), R ⁵ and R ⁶ each independently represent a monovalent organic group having 1 to 12 carbon atoms, Z represents a single bond, —O—, —S—, —SO ₂ —,> C═O, —CONH—, —COO— or a divalent organic group having 1 to 12 carbon atoms, e and f each independently represent an integer of 0 to 4, and n represents 0 or 1.

In the formula (4), R ⁷ , R ⁸ , Y, m, g and h are each independently synonymous with R ⁷ , R ⁸ , Y, m, g and h in the formula (2), and R ⁵ , R ⁶ , Z, n, e and f are independently the same as R ⁵ , R ⁶ , Z, n, e and f in the formula (3).

(3) Polyimide resin The polyimide resin is not particularly limited as long as it is a polymer compound containing an imide bond in a repeating unit. For example, it is described in JP-A-2006-199945 and JP-A-2008-163107. It can be synthesized by the method that has been.

(4) Fluorene polycarbonate resin The fluorene polycarbonate resin is not particularly limited as long as it is a polycarbonate resin containing a fluorene moiety, and can be synthesized, for example, by the method described in JP-A-2008-163194. .

(5) Fluorene polyester-based resin The fluorene polyester-based resin is not particularly limited as long as it is a polyester resin containing a fluorene moiety, and is described in, for example, JP 2010-285505 A or JP 2011-197450 A. Can be synthesized by any method.

(6) Fluorinated aromatic polymer resin The fluorinated aromatic polymer resin is not particularly limited, but has at least one fluorine-containing aromatic ring, an ether bond, a ketone bond, a sulfone bond, an amide bond, and an imide bond. And a polymer containing a repeating unit containing at least one bond selected from the group consisting of ester bonds, and can be synthesized, for example, by the method described in JP-A-2008-181121.

(7) Commercially available products Examples of commercially available transparent resins include the following commercially available products. Examples of commercially available cyclic olefin-based resins include Arton manufactured by JSR Corporation, ZEONOR manufactured by Zeon Corporation, APEL manufactured by Mitsui Chemicals, Inc., and TOPAS manufactured by Polyplastics Corporation. Examples of commercially available polyethersulfone resins include Sumika Excel PES manufactured by Sumitomo Chemical Co., Ltd. Examples of commercially available polyimide resins include Neoprim L manufactured by Mitsubishi Gas Chemical Co., Ltd. Examples of commercially available polycarbonate resins include Pure Ace manufactured by Teijin Limited. Examples of commercially available fluorene polycarbonate resins include Iupizeta EP-5000 manufactured by Mitsubishi Gas Chemical Co., Ltd. Examples of commercially available fluorene polyester resins include OKP4HT manufactured by Osaka Gas Chemical Co., Ltd. As a commercial item of acrylic resin, there can be cited NIPPON CATALYST ACRYVIEWER Co., Ltd. Examples of commercially available silsesquioxane resins include Silplus manufactured by Nippon Steel Chemical Co., Ltd.

<Near-infrared absorbing dye>
The resin substrate contains a near infrared absorbing dye.
The near-infrared absorbing dye is at least one selected from the group consisting of squarylium compounds, cyanine compounds, phthalocyanine compounds, naphthalocyanine compounds, croconium compounds, dithiol compounds, diimonium compounds, and porphyrin compounds. Is preferred. More preferably, the near-infrared absorbing dye contains at least a squarylium compound. More preferably, the near-infrared absorbing dye contains a squarylium-based compound and another near-infrared absorbing dye.

The maximum absorption wavelength of the squarylium compound is preferably 600 nm or more, more preferably 620 nm or more, particularly preferably 650 nm or more, and preferably less than 800 nm, more preferably 760 nm or less, particularly preferably 740 nm or less. When the absorption maximum wavelength is in such a wavelength range, sufficient near-infrared absorption characteristics and visible light transmittance can be compatible.

When the squarylium-based compound and other near infrared absorbing dye are used in combination, at least one absorption maximum wavelength of the other near infrared absorbing dye is preferably more than 600 nm, more preferably 640 nm or more, particularly preferably 670 nm or more. And preferably 800 nm or less, more preferably 780 nm or less, particularly preferably 760 nm or less. When the absorption maximum wavelength of other near-infrared absorbing dyes is in such a wavelength range, sufficient near-infrared absorption characteristics and visible light transmittance can be achieved at the same time, and a squarylium compound and other near-infrared absorbing dyes can be obtained. In combination with the other, the near-infrared absorbing dye can effectively absorb the fluorescence generated from the squarylium compound, and the scattered light intensity of the optical filter can be suppressed.

Specifically, the other near-infrared absorbing dye preferably contains at least one selected from the group consisting of a cyanine compound and a phthalocyanine compound, and particularly preferably contains a phthalocyanine compound. By using the squarylium compound in combination with the compound, an optical filter with less scattered light and better camera image quality can be obtained.

When the entire near-infrared absorbing dye is 100% by weight, the content of the squarylium compound is preferably 20 to 95% by weight, more preferably 25 to 85% by weight, and particularly preferably 30 to 80% by weight. When the content ratio of the squarylium-based compound is within the above range, it is possible to achieve both good visible light transmittance and incident angle dependency improvement property and scattered light reduction effect. Two or more squarylium compounds and other near infrared absorbing dyes may be used for each compound.

In the resin substrate, the content of the near infrared absorbing dye is preferably 0.01 to 5.0 parts by weight, more preferably 0.02 to 3. 5 parts by weight, particularly preferably 0.03 to 2.5 parts by weight. When the content of the near-infrared absorbing dye is within the above range, both good near-infrared absorption characteristics and high visible light transmittance can be achieved. Further, as described above, the near-infrared absorbing dye is preferably used at a concentration at which the transmittance of the resin substrate at the absorption maximum wavelength is 10% or less, particularly 8% or less, more particularly 6% or less.

《Squaryllium compound》
The squarylium-based compound preferably includes at least one selected from the group consisting of a squarylium-based compound represented by the formula (I) and a squarylium-based compound represented by the formula (II). Hereinafter, they are also referred to as “compound (I)” and “compound (II)”, respectively.

In the formula (I), R ^a , R ^b and Y satisfy the following condition (i) or (ii).
Condition (i)
A plurality of R ^a each independently represents a hydrogen atom, a halogen atom, a sulfo group, a hydroxyl group, a cyano group, a nitro group, a carboxy group, a phosphoric acid group, an —L ¹ or an —NR ^e R ^f group. R ^e and R ^f each independently represents a hydrogen atom, -L ^a , -L ^b , -L ^c , -L ^d, or -L ^e .

A plurality of R ^{b s} each independently represent a hydrogen atom, a halogen atom, a sulfo group, a hydroxyl group, a cyano group, a nitro group, a carboxy group, a phosphoric acid group, —L ¹ or —NR ^g R ^h group. R ^g and R ^h are each independently a hydrogen atom, -L ^a , -L ^b , -L ^c , -L ^d , -L ^e or -C (O) R ⁱ group (R ⁱ is -L ^a , Represents -L ^b , -L ^c , -L ^d or -L ^e ).

A plurality of Y each independently represents a —NR ^j R ^k group. R ^j and R ^k each independently represents a hydrogen atom, -L ^a , -L ^b , -L ^c , -L ^d, or -L ^e .
L ¹ is L ^a , L ^b , L ^c , L ^d , ^Le , L ^f , L ^g or L ^h .

L ^a to L ^h are
(L ^a ) an aliphatic hydrocarbon group having 1 to 9 carbon atoms,
(L ^b ) a halogen-substituted alkyl group having 1 to 9 carbon atoms,
(L ^c ) an alicyclic hydrocarbon group having 3 to 14 carbon atoms,
(L ^d ) an aromatic hydrocarbon group having 6 to 14 carbon atoms,
(L ^e ) a heterocyclic group having 3 to 14 carbon atoms,
(L ^f ) an alkoxy group having 1 to 9 carbon atoms,
(L ^g ) represents an acyl group having 1 to 9 carbon atoms, or (L ^h ) represents an alkoxycarbonyl group having 1 to 9 carbon atoms, and L ^a to L ^h may have a substituent L.

The substituent L is an aliphatic hydrocarbon group having 1 to 9 carbon atoms, a halogen-substituted alkyl group having 1 to 9 carbon atoms, an alicyclic hydrocarbon group having 3 to 14 carbon atoms, or an aromatic carbon group having 6 to 14 carbon atoms. It is at least one selected from the group consisting of a hydrogen group and a heterocyclic group having 3 to 14 carbon atoms.

L ^a to L ^h further have at least one atom or group selected from the group consisting of a halogen atom, a sulfo group, a hydroxyl group, a cyano group, a nitro group, a carboxy group, a phosphate group, and an amino group. Also good.

The total number of carbon atoms including the substituents of L ^a to L ^h is preferably 50 or less, more preferably 40 or less, and particularly preferably 30 or less. When the number of carbon atoms is larger than this range, it may be difficult to synthesize the dye, and the absorption intensity per unit weight tends to decrease.

Condition (ii)
At least one of two R ^a on one benzene ring is bonded to Y on the same benzene ring to form a heterocycle having 5 or 6 member atoms containing at least one nitrogen atom; The heterocyclic ring may have a substituent, and R ^b and R ^a that does not participate in the formation of the heterocyclic ring are each independently synonymous with R ^b and R ^a in the above (i).

R ^a in the above condition (i) is preferably a hydrogen atom, chlorine atom, fluorine atom, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group Cyclohexyl group, phenyl group, hydroxyl group, amino group, dimethylamino group, nitro group, more preferably hydrogen atom, chlorine atom, fluorine atom, methyl group, ethyl group, n-propyl group, isopropyl group, hydroxyl group. .

R ^b in the above condition (i) is preferably a hydrogen atom, a chlorine atom, a fluorine atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, or a tert-butyl group. Cyclohexyl group, phenyl group, hydroxyl group, amino group, dimethylamino group, cyano group, nitro group, acetylamino group, propionylamino group, N-methylacetylamino group, trifluoromethanoylamino group, pentafluoroethanoylamino group T-butanoylamino group, cyclohexinoylamino group, more preferably hydrogen atom, chlorine atom, fluorine atom, methyl group, ethyl group, n-propyl group, isopropyl group, hydroxyl group, dimethylamino group, nitro group , Acetylamino group, propionylamino group, trifluoromethanoylamino group, pentafur B ethanoyl group, t-butanoyl group, a cyclohexylene Sino-yl-amino group.

Y is preferably an amino group, methylamino group, dimethylamino group, diethylamino group, di-n-propylamino group, diisopropylamino group, di-n-butylamino group, di-t-butylamino group, N -Ethyl-N-methylamino group, N-cyclohexyl-N-methylamino group, more preferably dimethylamino group, diethylamino group, di-n-propylamino group, diisopropylamino group, di-n-butylamino group , A di-t-butylamino group.

In the condition (ii) of the formula (I), at least one of two R ^a on one benzene ring is bonded to Y on the same benzene ring, and at least 1 nitrogen atom is formed. Examples of the heterocyclic ring having 5 or 6 constituent atoms may include pyrrolidine, pyrrole, imidazole, pyrazole, piperidine, pyridine, piperazine, pyridazine, pyrimidine and pyrazine. Among these heterocyclic rings, a heterocyclic ring that constitutes the heterocyclic ring and in which one atom adjacent to the carbon atom constituting the benzene ring is a nitrogen atom is preferable, and pyrrolidine is more preferable. Examples of the substituent that the heterocyclic ring may have include a substituent L, and an aliphatic hydrocarbon group having 1 to 9 carbon atoms is preferable.

In the formula (II), X represents —O—, —S—, —Se—,> N—R ^c or> CR ^d ₂ ; a plurality of R ^c are each independently a hydrogen atom, —L ^a , -L ^b , -L ^c , -L ^d, or -L ^e ; a plurality of R ^{d s} independently represent a hydrogen atom, a halogen atom, a sulfo group, a hydroxyl group, a cyano group, a nitro group, a carboxy group, or a phosphate group , -L ¹ or -NR ^e R ^f group, adjacent R ^d groups may be linked to form an optionally substituted ring; L ^a to L ^e , L ¹ , R ^e and R ^f have the same meanings as L ^a to L ^e , L ¹ , R ^e and R ^f defined in the formula (I).

R ^c in the formula (II) is preferably a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, or an n-pentyl group. N-hexyl group, cyclohexyl group, phenyl group, trifluoromethyl group and pentafluoroethyl group, more preferably hydrogen atom, methyl group, ethyl group, n-propyl group and isopropyl group.

R ^d in the formula (II) is preferably a hydrogen atom, chlorine atom, fluorine atom, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl. Group, n-pentyl group, n-hexyl group, cyclohexyl group, phenyl group, methoxy group, trifluoromethyl group, pentafluoroethyl group, 4-aminocyclohexyl group, more preferably hydrogen atom, chlorine atom, fluorine atom Methyl group, ethyl group, n-propyl group, isopropyl group, trifluoromethyl group and pentafluoroethyl group.

X is preferably —O—, —S—, —Se—,>N—Me,>N—Et,> CH ₂ ,> C (Me) ₂ ,> C (Et) ₂ , and more. Preferred are -S-,> C (Me) ₂ , and> C (Et) ₂ . Me and Et each represent a methyl group and an ethyl group.

In the formula (II), adjacent R ^ds may be linked to form a ring. Examples of such a structure in which a ring formed by linking adjacent R ^{d s} to the ring in which R ^c and R ^{d are} bonded in Formula (II) include, for example, a benzoindolenin ring, α -Naphthoimidazole ring, β-naphthimidazole ring, α-naphthoxazole ring, β-naphthoxazole ring, α-naphthothiazole ring, β-naphthothiazole ring, α-naphthoselenazole ring, β-naphthoselenazole ring Can be mentioned.

Compound (I) and Compound (II) are represented by the following formulas (I-2) and (II-2) in addition to the following formulas (I-1) and (II-1). Thus, the structure can also be expressed by a description method that takes a resonance structure. That is, the difference between the following formula (I-1) and the following formula (I-2), and the difference between the following formula (II-1) and the following formula (II-2) is only the method of describing the structure. Both represent the same thing. In the present invention, unless otherwise specified, the structure of the squarylium compound is represented by a description method such as the following formula (I-1) and the following formula (II-1).

The structures of the compound (I) and the compound (II) are not particularly limited as long as they satisfy the requirements of the above formula (I) and the above formula (II). For example, the above formula (I-1) and the above formula (II-1) ), The right and left substituents bonded to the central four-membered ring may be the same or different, but it is preferable that they are the same because synthesis is easier. . For example, the compound represented by the following formula (I-3) and the compound represented by the following formula (I-4) can be regarded as the same compound.

Compound (I) and Compound (II) may be synthesized by a generally known method. For example, JP-A-1-228960, JP-A-2001-40234, JP-A-3196383, etc. It can be synthesized with reference to the method described.

<Near UV absorber>
The resin substrate can further contain a near ultraviolet absorber in addition to the near infrared absorbing dye. Examples of the near-ultraviolet absorber include at least one selected from the group consisting of azomethine compounds, indole compounds, benzotriazole compounds, and triazine compounds. The near-ultraviolet absorber preferably has at least one absorption maximum at a wavelength of 300 to 420 nm. By using such a resin substrate, an optical filter having a small incident angle dependency and a wide viewing angle can be obtained even in the near ultraviolet wavelength region.

The above squarylium compound, phthalocyanine compound, cyanine compound, near-UV absorber and other dyes can be synthesized by generally known methods, for example, Japanese Patent No. 336697, Japanese Patent No. 2846091. Patent No. 2,864,475, Patent No. 3703869, JP-A-60-228448, JP-A-1-14684, JP-A-1-228960, JP-A-4081149, JP-A-63. No. -125454, “Phthalocyanine—Chemistry and Function” (IPC, 1997), JP 2007-169315 A, JP 2009-108267 A, JP 2010-241873 A, JP 3699464 A. Described in Japanese Patent No. 4740631 Law can be referred to the composite.

<Other ingredients>
The resin substrate may further contain additives such as an antioxidant, a UV absorber other than the near UV absorber, a fluorescence quencher, and a metal complex compound, as long as the effects of the present invention are not impaired. Moreover, when manufacturing a resin-made board | substrate by cast shaping | molding mentioned later, manufacture of a resin-made board | substrate can be made easy by adding a leveling agent and an antifoamer. These other components may be used individually by 1 type, and may use 2 or more types together.

Antioxidants include, for example, 2,6-di-t-butyl-4-methylphenol, 2,2′-dioxy-3,3′-di-t-butyl-5,5′-dimethyldiphenylmethane, and And tetrakis [methylene-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane.

These additives may be mixed with a transparent resin or the like when producing a resin substrate, or may be added when producing a transparent resin. The addition amount of the additive is appropriately selected according to the desired characteristics, but is usually 0.01 to 5.0 parts by weight, preferably 0.05 to 5.0 parts by weight with respect to 100 parts by weight of the transparent resin. 2.0 parts by weight.

<Manufacturing method of resin substrate>
The resin substrate can be formed by, for example, melt molding or cast molding, and if necessary, a coating agent containing one or more of an antireflection agent, a hard coating agent, an antistatic agent and the like is coated after the molding. It can be manufactured by a method.

(1) A melt-molded resin substrate is, for example, a method of melt-molding pellets obtained by melt-kneading a transparent resin and a near-infrared absorbing dye; a resin composition containing a transparent resin and a near-infrared absorbing dye A pellet obtained by removing a solvent from a resin composition containing a transparent resin, a near-infrared absorbing dye and a solvent can be produced by a melt molding method. Examples of the melt molding method include injection molding, melt extrusion molding, and blow molding.

(2) A cast-molded resin substrate is, for example, a method in which a resin composition containing a transparent resin, a near-infrared absorbing dye and a solvent is applied onto a suitable substrate to remove the solvent; a near-infrared absorbing dye is contained It can also be produced by a method of applying the curable resin composition to be applied onto a suitable substrate and drying and curing.

Examples of the substrate include glass plates, steel belts, steel drums, and transparent resin films (for example, polyester films and cyclic olefin resin films).

The resin substrate can be obtained by peeling from the base material, and unless the effect of the present invention is impaired, the laminate of the base material and the coating film can be used as the resin substrate without peeling from the base material. Good.
Further, a method of coating an optical component such as a glass plate, a quartz component or a transparent plastic component with the resin composition and drying the solvent, or a method of coating and drying and curing the curable resin composition For example, a resin substrate can be formed directly on the optical component.

The solvent is not particularly limited as long as it is a solvent usually used for organic synthesis and the like. For example, hydrocarbons such as hexane and cyclohexane; alcohols such as methanol, ethanol, isopropanol, butanol, octanol; acetone, methyl ethyl ketone, methyl Ketones such as isobutyl ketone and cyclohexanone; esters such as ethyl acetate, butyl acetate, ethyl lactate, γ-butyrolactone, propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether acetate; ethers such as ethylene glycol monomethyl ether and diethylene glycol monobutyl ether Aromatic hydrocarbons such as benzene, toluene and xylene; Halogenated carbonization such as methylene chloride, chloroform and carbon tetrachloride Motorui; dimethylformamide, dimethylacetamide, it may be mentioned amides such as N- methylpyrrolidone. These solvents may be used alone or in combination of two or more.

The amount of residual solvent in the resin substrate obtained by the above method should be as small as possible. Specifically, the amount of the residual solvent is preferably 3% by weight or less, more preferably 1% by weight or less, and still more preferably 0.5% by weight or less with respect to the weight of the resin substrate. When the amount of residual solvent is in the above range, a resin substrate that can easily exhibit a desired function is obtained, in which deformation and characteristics hardly change.

[Near-infrared reflective film]
The near-infrared reflective film constituting the optical filter of the present invention is a film having the ability to reflect near-infrared light. In the present invention, the near-infrared reflective film may be provided on one side of the resin substrate or on both sides. When it is provided on one side, it is excellent in production cost and manufacturability, and when it is provided on both sides, an optical filter having high strength and less warpage can be obtained. When using an optical filter for a solid-state image sensor application, it is preferable that the warpage of the optical filter is small from the viewpoint of ease of mounting on the camera module, etc., so that a near-infrared reflective film is provided on both sides of the resin substrate. Is more preferable.

Examples of the near-infrared reflective film include an aluminum vapor-deposited film, a noble metal thin film, a resin film in which metal oxide fine particles mainly containing indium oxide and containing a small amount of tin oxide are dispersed, a high refractive index material layer, and a low refractive index material. A dielectric multilayer film in which layers are alternately stacked can be mentioned. Among the near-infrared reflective films, a dielectric multilayer film in which high refractive index material layers and low refractive index material layers are alternately laminated is more preferable.

As the material constituting the high refractive index material layer, a material having a refractive index greater than 1.7 can be used, and a material having a refractive index of usually more than 1.7 and 2.5 or less is selected. Examples of such materials include titanium oxide, zirconium oxide, tantalum pentoxide, niobium pentoxide, lanthanum oxide, yttrium oxide, zinc oxide, zinc sulfide, or indium oxide, and the like, and titanium oxide, tin oxide. And / or those containing a small amount of cerium oxide or the like (for example, 0 to 10% by weight with respect to the main component).

As the material constituting the low refractive index material layer, a material having a refractive index of 1.7 or less can be used, and a material having a refractive index of usually 1.2 or more and 1.7 or less is selected. Examples of such materials include silica, alumina, lanthanum fluoride, magnesium fluoride, and sodium hexafluoride sodium.

The refractive index is a refractive index in light having a wavelength of 550 nm.
The dielectric multilayer film is a multilayer in which a high refractive index material layer having a refractive index of more than 1.7 and 2.5 or less and a low refractive material layer having a refractive index of 1.2 to 1.7 are alternately stacked. A membrane is preferred.

In the dielectric multilayer film, the refractive index ratio between the highest refractive index layer and the lowest refractive index layer is preferably 1.3 or more, more preferably 1.4 or more, particularly preferably 1.5 or more. It is.

Further, in the high refractive index material layer and the low refractive index material layer laminated alternately, the ratio of the optical film thickness (physical film thickness x refractive index) between the adjacent high refractive index material layer and low refractive index material layer is 0. It is preferable to have 10 or more consecutive portions that are 8 to 1.2, more preferably 12 or more layers.

If the refractive index ratio between the high refractive index material layer and the low refractive index material layer or the film design of the dielectric multilayer film are within the above ranges, the near infrared reflection characteristics will improve and the near infrared cut characteristics will tend to improve. This is preferable.

When the optical filter has a dielectric multilayer film on both surfaces of the resin substrate, each of the dielectric multilayer films formed on both surfaces of the substrate has an arbitrary “10 consecutive layers satisfying (h) below”. When the average optical film thickness is compared, that is, when the average optical film thickness on one surface is compared with the average optical film thickness on the other surface, the dielectric multilayer film having the larger average optical film thickness The average optical film thickness is preferably 1.05 to 1.60 times, more preferably 1.10 to 1.55 times the average optical film thickness of the other dielectric multilayer film.
(H) The ratio of the optical film thickness (physical film thickness × refractive index) of the adjacent high refractive index material layer and low refractive index material layer is 0.8 to 1.2.

When the film configuration of the dielectric multilayer film formed on both surfaces of the substrate satisfies the above conditions, for example, near infrared rays in a wide wavelength range such as 700 to 1200 nm can be reflected more effectively, and the near infrared cut characteristics tend to be improved. Therefore, it is preferable.

The method for laminating the high refractive index material layer and the low refractive index material layer is not particularly limited as long as a dielectric multilayer film in which these material layers are laminated is formed. For example, a dielectric in which high-refractive index material layers and low-refractive index material layers are alternately laminated directly on a resin substrate by CVD, sputtering, vacuum deposition, ion-assisted deposition, or ion plating. A body multilayer film can be formed.

The thickness of each of the high refractive index material layer and the low refractive index material layer is usually preferably from 0.1λ to 0.5λ, where λ (nm) is the near infrared wavelength to be blocked. The value of λ (nm) is, for example, 700 to 1400 nm, preferably 750 to 1300 nm. When the thickness is within this range, the product of the refractive index (n) and the physical thickness (d) (n × d) is calculated by λ / 4, the optical thickness, the high refractive index material layer, and the low refractive index. The thickness of each layer of the material layer becomes almost the same value, and there is a tendency that the blocking / transmission of a specific wavelength can be easily controlled from the relationship between the optical characteristics of reflection / refraction.

The total number of high refractive index material layers and low refractive index material layers in the dielectric multilayer film is preferably 5 to 60 layers, more preferably 10 to 50 layers, as a whole, 12 More preferably, there are ˜50 layers. When the optical filter has a dielectric multilayer film on both surfaces of the resin substrate, the difference in the number of layers of the dielectric multilayer film formed on both surfaces of the substrate (that is, the number of layers of one multilayer film and the layer of the other multilayer film) The difference in number) is 12 or less, particularly preferably 10 or less, and the difference in physical film thickness (that is, the difference between the physical film thickness of one multilayer film and the physical film thickness of the other multilayer film) is 500 nm or less. More preferably, it is 450 nm or less, and particularly preferably 400 nm or less. It is preferable that the difference in the number of layers and the difference in physical film thickness of the dielectric multilayer films formed on both surfaces of the substrate are in the above ranges because the warpage of the optical filter tends to be further reduced.

In the present invention, for example, considering the absorption wavelength region of a resin substrate containing a near-infrared absorbing dye, the material constituting the high refractive index material layer and the low refractive index material layer, the high refractive index material layer, and the low refractive index An optical filter that satisfies the requirement (C) can be obtained by designing the near-infrared reflective film by appropriately selecting the thickness of each material layer, the order of lamination, and the number of laminations.

Here, the optimization of the near-infrared reflecting film is performed by using, for example, optical thin film design software (for example, manufactured by Essential Macleod, Thin Film Center) from the wavelength range cut by the near-infrared reflecting film as shown in FIG. The near-infrared reflective film can be designed so that the absorption by the near-infrared absorbing dye contained in the resin substrate exists over the wavelength range that transmits the infrared reflective film. Depending on the absorption waveform and addition amount of the near-infrared absorbing dye, in the case of the above-mentioned software, for example, for at least one near-infrared reflecting film, the design target transmittance from the visible region to the absorption maximum wavelength of the dye is 100%, etc. And the design target transmittance from the wavelength of the absorption maximum wavelength of the dye + 10 nm to the wavelength of the absorption maximum wavelength of the dye + 250 nm is set to 0% or the like.

[Other functional membranes]
In the optical filter of the present invention, the surface hardness of the resin substrate or near-infrared reflective film is between the resin substrate and the near-infrared reflective film such as a dielectric multilayer film within a range not impairing the effects of the present invention. Functional films such as an antireflection film, a hard coat film, and an antistatic film can be provided as appropriate for the purpose of improvement, chemical resistance improvement, antistatic and scratch removal.

For the purpose of improving the adhesion between the resin substrate and the functional film and / or near-infrared reflective film, and the adhesion between the functional film and the near-infrared reflective film, the surface of the resin substrate or functional film is subjected to corona treatment, plasma treatment, etc. The surface treatment may be performed.

[Characteristics etc. of optical filter]
The optical filter of the present invention includes the transparent resin substrate and the near-infrared reflective film formed on at least one surface thereof. For this reason, the optical filter of the present invention has a wide viewing angle even near the bottom of the transmission wavelength region, and is excellent in visible light transmittance and infrared ray cut characteristics. When such an optical filter is used for a solid-state imaging device, it is possible to obtain a high-quality image with excellent color reproducibility even for light incident from an oblique direction.

Also, near infrared light can be efficiently absorbed by using, for example, a dye having an absorption maximum at a wavelength of 600 to 800 nm as at least one kind of near infrared absorbing dye contained in the resin substrate. Therefore, by combining such a transparent resin substrate and a near-infrared reflective film, an optical filter with little incident angle dependency can be obtained.

[Use of optical filter]
The optical filter of the present invention has a wide viewing angle and has excellent near-infrared cutting ability and the like. Therefore, it is useful for correcting the visibility of a solid-state imaging device such as a CCD or CMOS image sensor of a camera module. In particular, digital still cameras, mobile phone cameras, digital video cameras, personal computer cameras, surveillance cameras, automotive cameras, TVs, in-vehicle devices for car navigation systems, personal digital assistants, video game machines, portable game machines, fingerprint authentication Useful for system devices, digital music players, etc. Furthermore, it is also useful as a heat ray cut filter attached to a glass plate of an automobile or a building.

[Solid-state imaging device]
The solid-state imaging device of the present invention includes the optical filter of the present invention. Here, the solid-state imaging device is an image sensor including a solid-state imaging device such as a CCD or a CMOS image sensor, and specifically includes a digital still camera, a mobile phone camera, a digital video camera, and the like.

〔The camera module〕
The camera module of the present invention includes the optical filter of the present invention. Here, the case where the optical filter of this invention is used for a camera module is demonstrated concretely. FIG. 1 is a schematic sectional view of the camera module.

FIG. 1A is a schematic cross-sectional view of the structure of a conventional camera module, and FIG. 1B shows the structure of a camera module that can be obtained when the optical filter 6 ′ of the present invention is used. It is a section schematic diagram showing one. In FIG. 1 (b), the optical filter 6 ′ of the present invention is disposed on the upper portion of the lens 5. However, the optical filter 6 ′ of the present invention includes the lens 5 and the sensor as shown in FIG. 1 (a). 7 can also be arranged.

In the conventional camera module, the light 10 has to be incident substantially perpendicular to the optical filter 6. Therefore, the filter 6 has to be disposed between the lens 5 and the sensor 7.

Here, since the sensor 7 is highly sensitive and there is a possibility that the sensor 7 may not operate correctly just by touching dust or dust of about 5 μm, the filter 6 disposed on the upper part of the sensor 7 does not generate dust or dust. It was necessary to be a thing which does not contain a foreign material. In addition, due to the characteristics of the sensor 7, it is necessary to provide a predetermined distance between the filter 6 and the sensor 7, which is one factor that hinders the reduction in the height of the camera module.

On the other hand, in the case of the optical filter 6 ′ of the present invention, there is no great difference between the transmission wavelengths of light incident from the vertical direction of the filter 6 ′ and light incident from 30 ° with respect to the vertical direction of the filter 6 ′. (As described above, since the incident angle dependency of the absorption (transmission) wavelength is small even near the bottom of the transmission wavelength region), the filter 6 ′ does not need to be disposed between the lens 5 and the sensor 7. It can also be placed on top of 5.

For this reason, when the optical filter 6 ′ of the present invention is used in a camera module, the camera module becomes easy to handle, and it is not necessary to provide a predetermined interval between the filter 6 ′ and the sensor 7. This makes it possible to reduce the height of the camera module.

Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples. “Parts” means “parts by weight” unless otherwise specified. Moreover, the measurement method of each physical property value and the evaluation method of the physical property are as follows.

<Molecular weight>
The molecular weight of the resin was measured by the following method (a) or (b) in consideration of the solubility of each resin in a solvent. In addition, about the resin synthesize | combined in the resin synthesis example 3 mentioned later, the logarithmic viscosity was measured by the following method (c) instead of the molecular weight measurement by these methods.

(A) Weight average molecular weight (Mw) and number average molecular weight (Mw) in terms of standard polystyrene using a GPC apparatus (150C type, column: H type column manufactured by Tosoh Corporation, developing solvent: o-dichlorobenzene) manufactured by WATERS Mn) was measured.

(B) A weight average molecular weight (Mw) and a number average molecular weight (Mn) in terms of standard polystyrene were measured using a GPC apparatus (HLC-8220 type, column: TSKgelα-M, developing solvent: tetrahydrofuran) manufactured by Tosoh Corporation.

(C) A part of the polyimide resin solution was put into anhydrous methanol to precipitate the polyimide resin, and filtered to separate from the unreacted monomer. 0.1 g of polyimide obtained by vacuum drying at 80 ° C. for 12 hours is dissolved in 20 mL of N-methyl-2-pyrrolidone, and the logarithmic viscosity (μ) at 30 ° C. is expressed by the following formula using a Canon-Fenske viscometer. Determined by

μ = {ln (ts / t0)} / C
t0: Flowing time of solvent ts: Flowing time of dilute polymer solution C: 0.5 g / dL

<Glass transition temperature (Tg)>
The glass transition temperature (Tg) of the resin was measured using a differential scanning calorimeter (DSC6200) manufactured by SII Nano Technologies, Inc. at a rate of temperature increase of 20 ° C. per minute under a nitrogen stream.

<Spectral transmittance>
The absorption maximum wavelength of the resin substrate and the transmittance at that wavelength, the transmittance in each wavelength region of the optical filter, and the aforementioned (Za) and (Zb) are spectrophotometers (U-4100 manufactured by Hitachi High-Technologies Corporation). ).

Here, with respect to the transmittance when measured from the vertical direction of the optical filter, the light transmitted perpendicular to the filter surface was measured as shown in FIG. The same applies to a resin substrate. Further, with respect to the transmittance when measured from an angle of 30 ° with respect to the vertical direction of the optical filter, light transmitted at an angle of 30 ° with respect to the vertical direction of the filter surface was measured as shown in FIG. .

In addition, this transmittance | permeability was measured using the said spectrophotometer on the conditions that light injects perpendicularly with respect to a filter surface or a resin-made substrate surface except the case where (Zb) is measured. When (Zb) is measured, it is measured using the spectrophotometer under the condition that light is incident at an angle of 30 ° with respect to the vertical direction of the filter surface.

<Haze value>
The haze value of the optical filter was measured by a method according to JIS K7105 using a haze meter (HZ-2) manufactured by Suga Test Instruments Co., Ltd.

<Refractive index>
A sample in which the target layers (silica layer and titanium oxide layer) whose refractive index is to be measured is formed as a single layer on a glass substrate is prepared, and a spectrophotometer (U-4100) manufactured by Hitachi High-Technologies Corporation is used. The transmittance and reflectance of the sample thus prepared were measured (the transmittance was measured from the direction perpendicular to the sample surface, and the reflectance was measured from an angle of 5 ° with respect to the direction perpendicular to the sample surface). The obtained transmittance and reflectance data were input to optical thin film design software (Essential Macintosh, manufactured by Thin Film Center), and function fitting was performed to obtain the refractive index of each target layer with respect to light having a wavelength of 550 nm.

<Resin synthesis example 1>
8-methyl-8-methoxycarbonyltetracyclo represented by the following formula (a) [4.4.0.1 ^2,5 . 1 ^7,10 ] Dodec-3-ene (hereinafter also referred to as “DNM”) 100 parts, 1-hexene (molecular weight regulator) 18 parts, and toluene (ring-opening polymerization solvent) 300 parts nitrogen-substituted reaction The vessel was charged and the solution was heated to 80 ° C. Next, 0.2 parts of a toluene solution of triethylaluminum (concentration 0.6 mol / liter) and a toluene solution of methanol-modified tungsten hexachloride (concentration 0.025 mol / liter) 0 as a polymerization catalyst were added to the solution in the reaction vessel. .9 parts was added and the solution was heated and stirred at 80 ° C. for 3 hours to cause a ring-opening polymerization reaction to obtain a ring-opening polymer solution. The polymerization conversion rate in this polymerization reaction was 97%.

1,000 parts of the ring-opening polymer solution thus obtained was charged into an autoclave, and 0.12 part of RuHCl (CO) [P (C ₆ H ₅ ) ₃ ] ₃ was added to the ring-opening polymer solution. Then, the hydrogenation reaction was performed by heating and stirring for 3 hours under the conditions of a hydrogen gas pressure of 100 kg / cm ² and a reaction temperature of 165 ° C.

After cooling the obtained reaction solution (hydrogenated polymer solution), the hydrogen gas was released. This reaction solution was poured into a large amount of methanol to separate and recover the coagulated product, and dried to obtain a hydrogenated polymer (hereinafter also referred to as “resin A”). The obtained resin A had a number average molecular weight (Mn) of 32,000, a weight average molecular weight (Mw) of 137,000, and a glass transition temperature (Tg) of 165 ° C.

<Resin synthesis example 2>
In a 3 L four-necked flask, 35.12 g (0.253 mol) of 2,6-difluorobenzonitrile, 87.60 g (0.250 mol) of 9,9-bis (4-hydroxyphenyl) fluorene, 41.46 g of potassium carbonate ( 0.300 mol), 443 g of N, N-dimethylacetamide (hereinafter also referred to as “DMAc”) and 111 g of toluene were added. Subsequently, a thermometer, a stirrer, a three-way cock with a nitrogen introduction tube, a Dean-Stark tube and a cooling tube were attached to the four-necked flask.

Next, after the flask was purged with nitrogen, the resulting solution was reacted at 140 ° C. for 3 hours, and the generated water was removed from the Dean-Stark tube as needed. When no more water was observed, the temperature was gradually raised to 160 ° C. and reacted at that temperature for 6 hours.

After cooling to room temperature (25 ° C.), the produced salt was removed with filter paper, the filtrate was poured into methanol for reprecipitation, and the filtrate (residue) was isolated by filtration. The obtained filtrate was vacuum-dried overnight at 60 ° C. to obtain a white powder (hereinafter also referred to as “resin B”) (yield 95%). The obtained resin B had a number average molecular weight (Mn) of 75,000, a weight average molecular weight (Mw) of 188,000, and a glass transition temperature (Tg) of 285 ° C.

<Resin synthesis example 3>
In a 500 mL five-necked flask equipped with a thermometer, stirrer, nitrogen introducing tube, dropping funnel with side tube, Dean-Stark tube and condenser tube, 1,4-bis (4-amino-α, α -Dimethylbenzyl) benzene (27.66 g, 0.08 mol) and 4,4′-bis (4-aminophenoxy) biphenyl (7.38 g, 0.02 mol) were added, and γ-butyrolactone (68.65 g) and N, It was dissolved in 17.16 g of N-dimethylacetamide. The obtained solution was cooled to 5 ° C. using an ice-water bath, and while maintaining the same temperature, 22.62 g (0.1 mol) of 1,2,4,5-cyclohexanetetracarboxylic dianhydride and an imidization catalyst As a result, 0.50 g (0.005 mol) of triethylamine was added all at once. After completion of the addition, the temperature was raised to 180 ° C. and refluxed for 6 hours while distilling off the distillate as needed. After completion of the reaction, the reaction solution was air-cooled until the internal temperature reached 100 ° C., diluted by adding 143.6 g of N, N-dimethylacetamide, cooled with stirring, and 264.16 g of a polyimide resin solution having a solid content concentration of 20% by weight. Got. A part of this polyimide resin solution was poured into 1 L of methanol to precipitate the polyimide. The polyimide separated by filtration was washed with methanol and dried in a vacuum dryer at 100 ° C. for 24 hours to obtain a white powder (hereinafter also referred to as “resin C”). The IR spectrum of the obtained resin C was measured, 1704 cm ^-1 characteristic of imido group, absorption of 1770 cm ^-1 were observed. The obtained resin C had a glass transition temperature (Tg) of 310 ° C. and a logarithmic viscosity of 0.87.

<Resin synthesis example 4>
9.167 kg (20.90 mol) of 9,9-bis {4- (2-hydroxyethoxy) phenyl} fluorene, 4.585 kg (20.08 mol) of bisphenol A, 9.000 kg (42.01 mol) of diphenyl carbonate , And 0.02066 kg (2.459 × 10 ⁻⁴ mol) of sodium bicarbonate were placed in a 50 L reactor equipped with a stirrer and a distillation apparatus, and heated to 215 ° C. over 1 hour under a nitrogen atmosphere under 760 Torr. Stir. Thereafter, the degree of vacuum was adjusted to 150 Torr over 15 minutes, and the mixture was held at 215 ° C. and 150 Torr for 20 minutes to conduct a transesterification reaction. Further, the temperature was raised to 240 ° C. at a rate of 37.5 ° C./Hr, and held at 240 ° C. and 150 Torr for 10 minutes. Thereafter, the pressure was adjusted to 120 Torr over 10 minutes and maintained at 240 ° C. and 120 Torr for 70 minutes. Thereafter, the pressure was adjusted to 100 Torr over 10 minutes and held at 240 ° C. and 100 Torr for 10 minutes. The polymerization reaction was further carried out by stirring for 10 minutes under the conditions of 240 ° C. and 1 Torr or less at 40 ° C. and 1 Torr or less. After completion of the reaction, nitrogen was introduced into the reactor to increase the pressure, and the produced polycarbonate resin (hereinafter also referred to as “resin D”) was extracted while being pelletized. The obtained resin D had a weight average molecular weight (Mw) of 41,000 and a glass transition temperature (Tg) of 152 ° C.

<Resin synthesis example 5>
To the reactor, 0.8 mol of 9,9-bis {4- (2-hydroxyethoxy) -3,5-dimethylphenyl} fluorene, 2.2 mol of ethylene glycol and 1.0 mol of dimethyl isophthalate were added and stirred. The mixture was gradually heated and melted to carry out the transesterification reaction, and then 20 × 10 ⁻⁴ moles of germanium oxide was added, and ethylene glycol was removed while gradually increasing the temperature and reducing the pressure until reaching 290 ° C. and 1 Torr or less. . Thereafter, the contents were taken out of the reactor to obtain pellets of polyester resin (hereinafter also referred to as “resin E”). The obtained resin E had a number average molecular weight (Mn) of 40,000 and a glass transition temperature (Tg) of 145 ° C.

<Resin synthesis example 6>
To a reactor equipped with a thermometer, a cooling pipe, a gas introduction pipe and a stirrer, 4,74′-bis (2,3,4,5,6-pentafluorobenzoyl) diphenyl ether (BPDE) 16.74 parts, 10.5 parts of 9-bis (4-hydroxyphenyl) fluorene (HF), 4.34 parts of potassium carbonate and 90 parts of DMAc were charged. The mixture was warmed to 80 ° C. and reacted for 8 hours. After completion of the reaction, the reaction solution was added into a 1% aqueous acetic acid solution with vigorous stirring with a blender. The precipitated reaction product was separated by filtration, washed with distilled water and methanol, and then dried under reduced pressure to obtain a fluorinated polyether ketone (hereinafter also referred to as “resin F”). The obtained resin F had a number average molecular weight (Mn) of 71,000 and a glass transition temperature (Tg) of 242 ° C.

[Example 1]
In a container, 100 parts of Resin A obtained in Synthesis Example 1, 0.03 part of a squarylium compound represented by the following formula (a-1) (hereinafter also referred to as “compound (a-1)”), A solution having a resin concentration of 20% by weight was obtained by adding 0.01 part of a phthalocyanine compound represented by (b-1) (hereinafter also referred to as “compound (b-1)”) and methylene chloride. .

Next, the obtained solution was cast on a smooth glass plate and dried at 20 ° C. for 8 hours, and then the coating film was peeled off from the glass plate. The peeled coating film was further dried at 100 ° C. under reduced pressure for 8 hours to obtain a resin substrate having a thickness of 0.1 mm, a length of 60 mm, and a width of 60 mm. The spectral transmittance of the resin substrate was measured to determine the absorption maximum wavelength. The results are shown in Table 4. The absorption maximum wavelength was 698 nm, and the transmittance at that wavelength was 1%.

Subsequently, a near-infrared reflective film (I) is formed on one surface of the obtained resin substrate, and a near-infrared reflective film (II) is formed on the other surface of the resin substrate, and the thickness is 0.106 mm. An optical filter was obtained.

The near-infrared reflective film (I) is formed by alternately laminating a silica (SiO ₂ ) layer and a titanium oxide (TiO ₂ ) layer at a deposition temperature of 100 ° C. (20 layers in total). The near-infrared reflective film (II) is formed by alternately laminating silica (SiO ₂ ) layers and titanium oxide (TiO ₂ ) layers at a deposition temperature of 100 ° C. (26 layers in total). In any of the near-infrared reflective films (I) and (II), the silica layer and the titanium oxide layer are formed from the resin substrate side from the titanium oxide layer, silica layer, titanium oxide layer,..., Silica layer, titanium oxide layer, The silica layers were alternately laminated in this order, and the outermost layer of the optical filter was a silica layer.

The near-infrared reflective films (I) and (II) were designed as follows.
The thickness of each layer and the number of layers are optically matched to the characteristics of the resin substrate and near-infrared absorbing dye so that both the antireflection effect in the visible region and the light-cutting effect in the near-infrared region can be achieved, taking into consideration the absorption characteristics of the pigment Optimization was performed using thin film design software (Essential Macleod, Thin Film Center). When performing optimization, in this example, the input parameters (Target values) to the software are as shown in Table 1 below.

As a result of optimization, in Example 1, the near-infrared reflective film (I) has a stacking number of 20 in which a silica layer having a thickness of 88 to 185 nm and a titanium oxide layer having a thickness of 98 to 108 nm are alternately stacked. The near-infrared reflective film (II) is a multilayer deposited film having 26 layers, in which a silica layer having a thickness of 78 to 156 nm and a titanium oxide layer having a thickness of 82 to 90 nm are alternately stacked. It was. The refractive index of the silica layer was 1.445, and the refractive index of the titanium oxide layer was 2.479. A portion where the ratio of the optical film thickness (physical film thickness × refractive index) between the adjacent high refractive index material layer and low refractive index material layer is 0.8 to 1.2 is continuous, and the film (I) is 19 The film (II) has 25 layers. Table 2 shows an example of the optimized film configuration.

The spectral transmittance of this optical filter was measured, and the optical characteristics in each wavelength region were evaluated. The results are shown in Table 4. The average transmittance at a wavelength of 430 to 580 nm was 91%, the average transmittance at a wavelength of 800 to 1000 nm was 1% or less, and the absolute value | Za−Zb | was 10 nm.

[Example 2]
A near-infrared reflective film (III) is formed on one surface of a resin substrate having a thickness of 0.1 mm, a length of 60 mm, and a width of 60 mm obtained in Example 1, and the near-infrared reflection film is formed on the other surface of the resin substrate. Film (IV) was formed, and an optical filter having a thickness of 0.105 mm was obtained.

The near-infrared reflective film (III) is formed by alternately laminating silica (SiO ₂ ) layers and titanium oxide (TiO ₂ ) layers at a deposition temperature of 100 ° C. (18 layers in total). The near-infrared reflective film (IV) is formed by alternately laminating silica (SiO ₂ ) layers and titanium oxide (TiO ₂ ) layers at a deposition temperature of 100 ° C. (18 layers in total). In any of the near-infrared reflective films (III) and (IV), the silica layer and the titanium oxide layer are the titanium oxide layer, silica layer, titanium oxide layer,..., Silica layer, titanium oxide layer, from the resin substrate side. The silica layers were alternately laminated in this order, and the outermost layer of the optical filter was a silica layer.

The near-infrared reflective films (III) and (IV) were designed as follows.
As a result of optimization in the same manner as in Example 1, in Example 2, the near-infrared reflective film (III) was formed by alternately laminating a silica layer having a film thickness of 36 to 186 nm and a titanium oxide layer having a film thickness of 11 to 109 nm. The near-infrared reflective film (IV) is formed by alternately laminating a silica layer having a film thickness of 31 to 156 nm and a titanium oxide layer having a film thickness of 10 to 94 nm. The multilayer deposited film became. The refractive index of the silica layer was 1.445, and the refractive index of the titanium oxide layer was 2.479. The portion where the ratio of the optical film thickness (physical film thickness × refractive index) between the adjacent high refractive index material layer and low refractive index material layer is 0.8 to 1.2 is continuous, and the film (III) is 15 The film (IV) has 15 layers. Table 3 shows an example of the optimized film configuration.

Table 4 shows the evaluation results of the optical characteristics.
[Example 3] to [Example 14] and [Comparative Example 1] to [Comparative Example 2]
In Example 1, a transparent resin, a near infrared absorbing dye, a solvent, and a film drying condition shown in Table 4 were used to produce a resin substrate, and further, the thickness and the number of layers of each multilayer deposited film were optimized. An optical filter having a thickness of 0.106 mm was obtained in the same manner as in Example 1 except for the above. The results are shown in Table 4. In Table 4, the resin concentration of the solution is 20% by weight.

Various compounds used in Examples and Comparative Examples are as follows.
Resin A: Cyclic olefin resin (resin synthesis example 1)
Resin B: Aromatic polyether resin (resin synthesis example 2)
Resin C: Polyimide resin (resin synthesis example 3)
Resin D: Fluorene polycarbonate resin (resin synthesis example 4)
Resin E: Fluorene polyester resin (resin synthesis example 5)
Resin F: Fluorinated polyether ketone (resin synthesis example 6)
Resin G: Cyclic Olefin Resin “Zeonor 1420R”
(Nippon Zeon Corporation)
Resin H: Cyclic olefin resin “APEL # 6015”
(Mitsui Chemicals)
Resin I: Polycarbonate resin “Pure Ace” (manufactured by Teijin Limited)
Resin J: Polyethersulfone resin “Sumilite FS-1300”
(Sumitomo Bakelite Co., Ltd.)
Resin K: Heat-resistant acrylic resin "Acryviewer" (Nippon Shokubai Co., Ltd.)
Compound (a-1): A squarylium compound represented by the following formula (a-1)

Compound (a-2): A squarylium compound represented by the following formula (a-2)

Compound (b-1): phthalocyanine compound represented by the following formula (b-1)

Compound (b-2): phthalocyanine compound represented by the following formula (b-2)

Compound (c-1): Cyanine compound represented by the following formula (c-1)

Solvent (1): Methylene chloride Solvent (2): N, N-dimethylacetamide Solvent (3): Ethyl acetate / toluene (weight ratio: 5/5)
Solvent (4): cyclohexane / xylene (weight ratio: 7/3)
Solvent (5): cyclohexane / methylene chloride (weight ratio: 99/1)
Solvent (6): N-methyl-2-pyrrolidone

Moreover, the film drying conditions of Examples and Comparative Examples in Table 4 are as follows.
Condition (1): 20 ° C./8 hr → under reduced pressure 100 ° C./8 hr
Condition (2): 60 ° C./8 hr → 80 ° C./8 hr
→ Under reduced pressure 140 ℃ / 8hr
Condition (3): 60 ° C./8 hr → 80 ° C./8 hr
→ Under reduced pressure 100 ℃ / 24hr
Condition (4): 40 ° C./4 hr → 60 ° C./4 hr
→ Under reduced pressure 100 ℃ / 8hr
In addition, the coating film was peeled from the glass plate before drying under reduced pressure.

As is clear from the results of each example, the optical filter satisfying the above requirements of the present invention has excellent visible light transmittance and near-infrared cut characteristics, and also has a wide viewing angle near the bottom of the transmission wavelength region. In addition, various characteristics required for a solid-state imaging device can be satisfied in a balanced manner. For this reason, the optical filter of the present invention can be suitably used particularly for solid-state imaging device applications as compared with conventional optical filters.

1: Camera module 2: Lens barrel 3: Flexible substrate 4: Hollow package 5: Lens 6, 6 ': Optical filter 7: CCD or CMOS image sensor 8: Optical filter 9: Spectrophotometer 10: Light

Claims (10)

1. A transparent resin substrate containing a near-infrared absorbing dye,
   A near-infrared reflective film formed on at least one surface of the substrate;
   An optical filter that satisfies the following requirements (A) to (C):
   (A) In the wavelength range of 430 to 580 nm, the average value of the transmittance when measured from the vertical direction of the optical filter is 75% or more.
   (B) In the wavelength range of 800 to 1000 nm, the average value of transmittance when measured from the vertical direction of the optical filter is 20% or less.
   (C) In the wavelength range of 560 to 800 nm, the longest wavelength value (Za) at which the transmittance when measured from the vertical direction of the optical filter is 10%, and an angle of 30 ° with respect to the vertical direction of the optical filter The absolute value | Za−Zb | of the difference from the longest wavelength value (Zb) at which the transmittance is 10% when measured from is less than 25 nm.
2. The optical filter according to claim 1, wherein the absorption maximum wavelength of the transparent resin substrate containing a near-infrared absorbing dye is 600 to 800 nm.
3. The optical filter according to claim 1 or 2, wherein a transmittance at a maximum absorption wavelength when measured from the vertical direction of a resin substrate containing a near-infrared absorbing dye is 10% or less.
4. The transparent resin constituting the transparent resin substrate is a cyclic olefin resin, aromatic polyether resin, polyimide resin, fluorene polycarbonate resin, fluorene polyester resin, polycarbonate resin, polyamide resin, polyarylate resin , Polysulfone resin, polyethersulfone resin, polyparaphenylene resin, polyamideimide resin, polyethylene naphthalate resin, fluorinated aromatic polymer resin, (modified) acrylic resin, epoxy resin, allyl ester The optical filter according to any one of claims 1 to 3, wherein the optical filter is at least one resin selected from the group consisting of a series resin and a silsesquioxane resin.
5. The transparent resin substrate is at least one kind selected from the group consisting of squarylium compounds, cyanine compounds, phthalocyanine compounds, naphthalocyanine compounds, croconium compounds, dithiol compounds, diimonium compounds and porphyrin compounds. The optical filter according to any one of claims 1 to 4, comprising an infrared absorbing dye.
6. 6. The method according to claim 1, wherein the near-infrared absorbing dye contains at least one selected from the group consisting of a squarylium compound represented by formula (I) and a squarylium compound represented by formula (II). The optical filter according to item.
   

   

   [In the formula (I), R ^a , R ^b and Y satisfy the following condition (i) or (ii):
   (I) a plurality of R ^{a s} each independently represent a hydrogen atom, a halogen atom, a sulfo group, a hydroxyl group, a cyano group, a nitro group, a carboxy group, a phosphate group, —L ¹ or —NR ^e R ^f group, And R ^e and R ^f each independently represents a hydrogen atom, -L ^a , -L ^b , -L ^c , -L ^d or -L ^e ;
   A plurality of R ^{b s} each independently represent a hydrogen atom, a halogen atom, a sulfo group, a hydroxyl group, a cyano group, a nitro group, a carboxy group, a phosphate group, —L ¹ or —NR ^g R ^h group, where R ^g And R ^h are each independently a hydrogen atom, -L ^a , -L ^b , -L ^c , -L ^d , -L ^e or -C (O) R ⁱ group (R ⁱ is -L ^a , -L ^b represents -L ^c , -L ^d or -L ^e );
   A plurality of Y's independently represent an —NR ^j R ^k group, wherein R ^j and R ^k are each independently a hydrogen atom, —L ^a , —L ^b , —L ^c , —L ^d, or —L represents ^e ;
   L ¹ is an ^{L a, L b, L c} , L d, L e, L f, L g or L ^h;
   L ^a to L ^h are
   (L ^a ) an aliphatic hydrocarbon group having 1 to 9 carbon atoms,
   (L ^b ) a halogen-substituted alkyl group having 1 to 9 carbon atoms,
   (L ^c ) an alicyclic hydrocarbon group having 3 to 14 carbon atoms,
   (L ^d ) an aromatic hydrocarbon group having 6 to 14 carbon atoms,
   (L ^e ) a heterocyclic group having 3 to 14 carbon atoms,
   (L ^f ) an alkoxy group having 1 to 9 carbon atoms,
   (L ^g ) represents an acyl group having 1 to 9 carbon atoms, or (L ^h ) represents an alkoxycarbonyl group having 1 to 9 carbon atoms, and the L ^a to L ^h may have a substituent L;
   The substituent L is an aliphatic hydrocarbon group having 1 to 9 carbon atoms, a halogen-substituted alkyl group having 1 to 9 carbon atoms, an alicyclic hydrocarbon group having 3 to 14 carbon atoms, or an aromatic carbon group having 6 to 14 carbon atoms. At least one selected from the group consisting of a hydrogen group and a heterocyclic group having 3 to 14 carbon atoms;
   L ^a to L ^h further have at least one atom or group selected from the group consisting of a halogen atom, a sulfo group, a hydroxyl group, a cyano group, a nitro group, a carboxy group, a phosphate group, and an amino group. Well;
   (Ii) At least one of two R ^a on one benzene ring is bonded to Y on the same benzene ring to form a heterocyclic ring having 5 or 6 constituent atoms containing at least one nitrogen atom. And the heterocyclic ring may have a substituent, and R ^b and R ^{a that} is not involved in the formation of the heterocyclic ring are independently the same as R ^b and R ^{a in} (i) above. ]
   

   

   [In the formula (II), X represents —O—, —S—, —Se—,> N—R ^c or> CR ^d ₂ ; a plurality of R ^c are each independently a hydrogen atom, —L ^a; , -L ^b , -L ^c , -L ^d or -L ^e ; a plurality of R ^{d s} independently represent a hydrogen atom, halogen atom, sulfo group, hydroxyl group, cyano group, nitro group, carboxy group, phosphoric acid A group, -L ¹ or -NR ^e R ^f group, and adjacent R ^d groups may be linked to form an optionally substituted ring; L ^a to L ^e , L ¹ , R ^e and R ^f have the same definitions as L ^a to L ^e , L ¹ , R ^e and R ^f defined in the formula (I). ]
7. The transparent resin substrate;
   The optical filter according to any one of claims 1 to 6, further comprising the near-infrared reflective film formed on both surfaces of the substrate.
8. The optical filter according to any one of claims 1 to 7, which is used for a solid-state imaging device.
9. A solid-state imaging device comprising the optical filter according to any one of claims 1 to 7.
10. A camera module comprising the optical filter according to any one of claims 1 to 7.

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