WO2015022892A1

WO2015022892A1 - Optical filter and device using optical filter

Info

Publication number: WO2015022892A1
Application number: PCT/JP2014/070706
Authority: WO
Inventors: 幸恵田中
Original assignee: Jsr株式会社
Priority date: 2013-08-13
Filing date: 2014-08-06
Publication date: 2015-02-19
Also published as: TW201506463A

Abstract

[Problem] To provide an optical filter having high visible light transmittance, and having, across a wide range of infrared wavelengths of 800 to 1200 nm, excellent light ray-cutting properties even against light rays with a high angle of incidence. [Solution] This optical filter has a transparent resin substrate and a near infrared reflecting film formed on at least one surface of the substrate, and satisfies conditions (A) and (B) below. (A) In a wavelength range of 430 to 580 nm, the average value of transmittance when measured perpendicular to the optical filter is at least 75%. (B) In a wavelength range of 800 to 1200 nm, the average value of reflectance when measured from one side of the optical filter at a 45° angle to the perpendicular of the optical filter is at least 70%.

Description

Optical filter and apparatus using the filter

The present invention relates to an optical filter and an apparatus using the filter.

In a solid-state imaging device such as a video camera, a digital still camera, 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.

On the other hand, 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 applicant has used a transparent resin substrate containing a near-infrared absorbing dye having an absorption maximum at a specific wavelength, so that a near-infrared cut filter with little change in optical characteristics can be obtained even when the incident angle is changed. It has been found that it can be obtained, and Patent Document 3 proposes a near-infrared cut filter having a wide viewing angle and a high visible light transmittance.

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 and the like, and it is desired to suppress the generation of ghost light.
According to the study by the present inventors, in order to satisfy the demand for higher image quality, and particularly to suppress the generation of ghost light, in the optical filter, in addition to high visible light transmittance, a wide range of wavelengths from 800 to 1200 nm. In the infrared region, a high light cut characteristic is required even for a light beam having a high incident angle. Conventional optical filters cannot satisfy such characteristics in a well-balanced manner. This invention makes it a subject to provide the optical filter which has the said light cut characteristic.

As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by an optical filter that satisfies the following requirements (A) to (B), and have completed the present invention. Examples of embodiments of the present invention are shown below.
[1] An optical filter having a transparent resin substrate and a near-infrared reflective film formed on at least one surface of the substrate and satisfying the following requirements (A) to (B):
(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 1200 nm, the average value of the reflectance when measured from one surface side of the optical filter at an angle of 45 ° with respect to the vertical direction of the optical filter is 70% or more.
[2] 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 The optical filter according to [1], which is at least one resin selected from the group consisting of an allyl ester resin and a silsesquioxane resin.
[3] The optical filter according to [1] or [2], wherein the transparent resin substrate contains a near-infrared absorbing dye.
[4] 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. The optical filter according to the above [3], which contains a kind of near-infrared absorbing dye.
[5] The near-infrared absorbing dye contains at least one selected from the group consisting of a squarylium compound represented by formula (I) described later and a squarylium compound represented by formula (II) described later. The optical filter according to [3] or [4].
[6] In the wavelength range of 800 to 1200 nm, the average reflectance when measured from an angle of 45 ° with respect to the vertical direction of the optical filter is 70% when measured from any side of the optical filter. The optical filter according to any one of [1] to [5] above.
[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, there is provided an optical filter having a high visible light transmittance and a high light-cutting characteristic even for a light having a high incident angle in a wide infrared region having a wavelength of 800 to 1200 nm. Can do. When such an optical filter is used for a solid-state imaging device, a ghost light is not generated and a camera image with good image quality can be obtained even in a small camera module such as a mobile device.

FIG. 1A is a schematic diagram showing a method for measuring the transmittance when measured from the vertical direction of the optical filter. FIG. 1B is a schematic diagram illustrating a method of measuring the reflectance when measured from an angle of 45 ° with respect to the vertical direction of the optical filter. FIG. 1C is a schematic diagram illustrating a method of measuring the reflectance when measured from an angle of 5 ° with respect to the vertical direction of the optical filter.

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 (B).
(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. The vertical direction of the optical filter means a direction perpendicular to the filter surface.

(B) In the region of wavelength 800 to 1200 nm, the average reflectance when measured from one side of the optical filter at an angle of 45 ° with respect to the vertical direction of the optical filter is 70% or more. This average value is preferably 80% or more, more preferably 90% or more. The reflectance measured from an angle of 45 ° with respect to the vertical direction of the optical filter is also referred to as “45 ° reflectance”.

In the present invention, it is preferable that the average value of the 45 ° reflectance measured from one surface side of the optical filter and the average value of the 45 ° reflectance measured from the other surface side are both 70% or more, More preferably, it is 75% or more, More preferably, it is 85% or more.

By satisfying the requirement (B), the optical filter has a high light-cut characteristic in a wide range of infrared regions, even for light rays with a high incident angle, for example, light rays with an incident angle of about 45 ° with respect to the vertical direction of the filter. Can be realized. Therefore, a wide viewing angle can be ensured, and generation of ghost light in the camera image can be suppressed.

In the present invention, a near-infrared reflecting film having a high average value of 45 ° reflectance in a wavelength region of 800 to 1200 nm is formed on a transparent resin substrate, so that light in the near-infrared region is effectively cut, and a wavelength of 800 An optical filter having a sufficiently high 45 ° reflectance can be obtained in the region of ˜1200 nm. Thereby, a ghost can be reduced and the image quality of the obtained camera image improves.

In the present invention, the conditions described later, for example, a high refractive index material, a low refractive index material, each high refractive index material, and a low refractive index material are laminated so as to achieve both an antireflection effect in the visible range and a light cut effect in the near infrared range. A near-infrared reflective film in which the order of the thickness, the thickness of each layer, the number of layers, and the like are optimized can be provided on the transparent resin substrate. As a result, an optical filter having sufficient reflection characteristics can be obtained even in a light beam having an incident angle of 45 ° with respect to the vertical direction of the optical filter in the wavelength region of 800 to 1200 nm. From the viewpoint of calculation accuracy and time reduction, optical thin film design software (for example, manufactured by Essential Macleod, Thin Film Center) can be used to optimize the near-infrared reflective film.

In addition, in order to reduce the transmittance at a wavelength of 800 to 1200 nm, in addition to the application of the near-infrared reflective film described above, a dye having absorption in the wavelength range of 800 to 1200 nm in a range that does not adversely affect the transmittance in the visible range. Further, metal-containing fine particles and the like can be further added to the transparent resin substrate.

In the present invention, for example, an optical filter satisfying all of the requirements (A) to (B) in a well-balanced manner can be obtained by using a transparent resin substrate and controlling the properties of the near-infrared reflective film. Since the optical filter of the present invention satisfies all the requirements (A) to (B), 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.

The optical filter of the present invention preferably further satisfies the requirement (C). When the requirement (B) is satisfied in the optical filter, the requirement (C) is also usually satisfied.
(C) In the wavelength range of 800 to 1200 nm, the average reflectance measured from one surface side of the optical filter at an angle of 5 ° with respect to the vertical direction of the optical filter is 70% or more. This average value is preferably 80% or more, more preferably 90% or more. The reflectance measured from an angle of 5 ° with respect to the vertical direction of the optical filter is also referred to as “5 ° reflectance”.

As with requirement (B), the average value of the 5 ° reflectance measured from one surface side of the optical filter and the average value of the 5 ° reflectance measured from the other surface side are both 70% or more. Is preferable, more preferably 80% or more, and still more preferably 90% or more.

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

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, but is preferably 30 to 250 μm, more preferably 40 to 200 μm, and 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 preferably contains a near-infrared absorbing dye from the viewpoint of imparting near-infrared absorption characteristics to the optical filter in addition to the above-described near-infrared reflection characteristics and realizing better near-infrared cut characteristics.

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 compound is within the above range, both a good visible light transmittance and a scattered light reduction effect can be achieved. 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 3.3 parts by weight with respect to 100 parts by weight of the transparent resin used when the resin substrate is manufactured. 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.

《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 containing 5 or 6 atoms 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-naphthothiadazole 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 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. In addition, below, it demonstrates based on the example which mix | blends a near-infrared absorption pigment | dye.

(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 the resin composition on an optical part such as a glass plate, a quartz part or a transparent plastic part 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 more than 1.7 and 2.5 or less is usually 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 to 1.7 is selected. Examples of such materials include silica, alumina, lanthanum fluoride, magnesium fluoride, and sodium hexafluoride sodium.

In the dielectric multilayer film, a high refractive index material layer having a refractive index of more than 1.7 and not more than 2.5 and a low refractive material layer having a refractive index of 1.2 to 1.7 are alternately laminated. A multilayer film is preferable.

The above refractive index is a refractive index in light having a wavelength of 550 nm. The refractive index can be measured, for example, as follows. A sample in which a target layer whose refractive index is to be measured is deposited as a single layer on a glass substrate is prepared, and the transmittance of the prepared sample is measured using a spectrophotometer (U-4100) manufactured by Hitachi High-Technologies Corporation. And reflectivity (transmittance and reflectivity are measured from an angle of 5 ° with respect to the direction perpendicular to the sample surface). The obtained transmittance and reflectance data are input to optical thin film design software (Essential Macleod, Thin Film Center), and the refractive index of each target layer with respect to light having a wavelength of 550 nm is obtained by performing function fitting.

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 the high refractive index material layer and the low refractive index material layer in the dielectric multilayer film is preferably 5 to 60 layers, more preferably 10 to 50 layers, as a whole, 30 More preferably, there are ˜50 layers.

In the present invention, for example, the material constituting the high refractive index material layer and the low refractive index material layer, the thickness of each layer of the high refractive index material layer and the low refractive index material layer, the order of lamination, and the number of laminations are appropriately selected. Thus, for example, an optical filter having sufficient reflection characteristics can be obtained even for a light ray having an incident angle of 45 ° with respect to the vertical direction of the filter in a wavelength region of 800 to 1200 nm.

Here, in order to optimize the above conditions, as described above, for example, using optical thin film design software (for example, Essential Macleod, manufactured by Thin Film Center), the 45 ° reflectance in the wavelength region of 800 to 1200 nm is high. Set the parameters so that In the case of the above software, for example, the target transmittance at a wavelength of 800 to 1200 nm is set to 0%, the value of Incident Angle is set to 45 °, and the value of Target Tolerance is set to 0.5 or less. Thus, by optimizing the above conditions, the 45 ° reflectance can be increased.

[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. Therefore, the optical filter of the present invention is excellent in transmittance characteristics and near-infrared reflection characteristics, particularly in light reflection characteristics with respect to light having a high incident angle in a wide infrared region having a wavelength of 800 to 1200 nm. When such an optical filter is used for a solid-state imaging device, high image quality can be achieved, and specifically, a good camera image with little ghost or the like can be obtained.

Further, 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 preferably blended in the resin substrate. . Therefore, an optical filter having excellent near-infrared absorption / reflection characteristics can be obtained by combining such a transparent resin substrate and a near-infrared reflective film.

[Use of optical filter]
The optical filter of the present invention has excellent near-infrared cut characteristics as described above. 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. For example, the camera module of the present invention includes the optical filter of the present invention.

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) The weight average molecular weight (Mw) and 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 and reflectance>
The absorption maximum wavelength of the resin substrate and the transmittance and reflectance in each wavelength region of the optical filter were measured using a spectrophotometer (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. When measuring the absorption maximum wavelength of the resin substrate, the transmittance of the substrate was measured in the same manner to obtain the absorption maximum wavelength. These transmittances are measured using the spectrophotometer under the condition that light is incident on the filter surface perpendicularly.

Moreover, in the reflectance when measured from an angle of 45 ° or 5 ° with respect to the vertical direction of the optical filter, the optical filter is installed in a jig attached to the apparatus as shown in FIG. 1 (b) or (c). Measurements were made. When the deposited film is formed on both surfaces of the resin substrate, the reflectivity is defined as the first surface (the first surface) on which the deposited film is formed and the second deposited surface (the second surface) is the B surface. When a vapor-deposited film is formed on one side of a resin substrate, the surface on which the vapor-deposited film is not formed is A-side, and the surface on which the vapor-deposited film is formed is the B-side, and light enters from the A-side and B-side. The reflectivity when measured was measured. These reflectivities are measured using the spectrophotometer under conditions where light is incident at an angle of 45 ° or 5 ° with respect to the vertical direction of the filter surface.

<Ghost>
After removing the optical filter arranged on the sensor of a commercially available digital camera (DSC-RX100 manufactured by Sony Corporation), the optical filter obtained in the example or the comparative example was arranged, and photographing was performed. The photographed image was projected and the presence or absence of ghost light was visually confirmed. The case where generation of ghost light was recognized was defined as BB, and the case where generation of ghost light was not observed was defined as AA.

<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 the resin A obtained in Synthesis Example 1, 0.03 part of a squarylium compound represented by the formula (a-1) described later (hereinafter also referred to as “compound (a-1)”), described later. 0.01 part of a phthalocyanine compound represented by the formula (b-1) (hereinafter also referred to as “compound (b-1)”) and methylene chloride are further added to form a solution having a resin concentration of 20% by weight. Obtained.

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 7. The absorption maximum wavelength was 698 nm.

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 at a deposition temperature of 100 ° C., and is formed by alternately laminating silica (SiO ₂ ) layers and titanium oxide (TiO ₂ ) layers (18 layers in total). The near-infrared reflective film (II) is formed at a deposition temperature of 100 ° C., and is formed by alternately stacking silica (SiO ₂ ) layers and titanium oxide (TiO ₂ ) layers (18 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 order of lamination of the silica layer and the titanium oxide layer of the near-infrared reflective film is the same in other examples below.

The near-infrared reflective films (I) and (II) were designed as follows.
For the thickness of each layer, optical thin film design software (Essential Macleod, manufactured by Thin Film Center Co., Ltd.) is 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. ) Was used for optimization. When performing optimization, in this example, the input parameters (Target values) to the software are as shown in Table 1 below. Further, for optimization, the number of layers and the transmittance and reflectance of the optical filter finally obtained (target values; see Table 7) were set as input parameters.

As a result of the optimization, in Example 1, the near-infrared reflective film (I) is formed by alternately stacking a silica layer having a film thickness of 78 to 161 nm and a titanium oxide layer having a film thickness of 80 to 93 nm. The near-infrared reflective film (II) is a multi-layer vapor-deposited film having 18 layers, in which a silica layer having a thickness of 38 to 198 nm and a titanium oxide layer having a thickness of 11 to 115 nm are alternately laminated. It was. Table 2 shows an example of the optimized film configuration.

The spectral transmittance and reflectance of this optical filter were measured, and the optical characteristics in each wavelength region were evaluated. The results are shown in Table 7. The average transmittance measured from the near-infrared reflecting film (I) side of the optical filter at a wavelength of 430 to 580 nm is 87%, and the near-infrared reflecting film (I) side of the optical filter at a wavelength of 800 to 1200 nm (A The average value of 45 ° reflectivity measured from the surface) was 93%, the average value of 5 ° reflectivity was 97%, and 45 measured from the near-infrared reflective film (II) side (B surface) of the optical filter. The average value of ° reflectivity was 92%, and the average value of 5 ° reflectivity was 97%. Moreover, generation | occurrence | production of the ghost light was not recognized.

[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 at a deposition temperature of 100 ° C., and is formed by alternately stacking silica (SiO ₂ ) layers and titanium oxide (TiO ₂ ) layers (26 layers in total). The near-infrared reflective film (IV) is formed at a deposition temperature of 100 ° C., and is formed by alternately laminating silica (SiO ₂ ) layers and titanium oxide (TiO ₂ ) layers (20 layers in total).

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 based on input parameters to the software (Target value, number of layers, transmittance and reflectance of optical filter finally obtained) The film (III) is a multilayer deposited film having 26 layers, in which a silica layer having a thickness of 31 to 158 nm and a titanium oxide layer having a thickness of 7 to 89 nm are alternately stacked, and the near-infrared reflective film (IV) is Thus, a multilayer deposited film having 20 layers was obtained by alternately laminating a silica layer having a film thickness of 39 to 199 nm and a titanium oxide layer having a film thickness of 12 to 116 nm. Table 3 shows an example of the optimized film configuration.

Table 7 shows the evaluation results of the optical characteristics. In this example, the transmittance at a wavelength of 430 to 580 nm is from the near infrared reflecting film (III) side (A surface) of the optical filter, and the reflectance at a wavelength of 800 to 1200 nm is from the near infrared reflecting film (III of the optical filter). ) Side (A surface) and near-infrared reflective film (IV) side (B surface).

[Example 3]
A near-infrared reflective film (V) was 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 an optical filter having a thickness of 0.105 mm was obtained.

The near-infrared reflective film (V) is formed at a deposition temperature of 100 ° C., and is formed by alternately laminating silica (SiO ₂ ) layers and titanium oxide (TiO ₂ ) layers (40 layers in total).
The near-infrared reflective film (V) is designed with the input parameters (Target values) to the software as shown in Table 4 below, and the number of layers and the transmittance and reflectance of the optical filter finally obtained ( Except that the target value (see Table 7) was set as an input parameter, and a silica layer having a film thickness of 36 to 193 nm and a titanium oxide layer having a film thickness of 10 to 113 nm were alternately laminated. As a result, a multi-layer vapor deposition film having 40 layers was obtained. Table 5 shows an example of the optimized film configuration.

[Example 4] to [Example 15]
Using the transparent resin, near-infrared absorbing dye, solvent and film drying conditions shown in Table 7, a resin substrate was produced in the same procedure as in Example 1, and the thickness of each layer of the multilayer deposited film was further determined. An optical filter having a thickness of 0.106 mm was obtained in the same manner as in Example 2 except that optimization was performed. The results are shown in Table 7. In Table 7, the resin concentration of the solution is 20% by weight.

[Comparative Example 1]
An optical filter composed of a resin substrate was produced in the same procedure as in Example 1 by employing the transparent resin, near-infrared absorbing dye, solvent and film drying conditions shown in Table 7. The results are shown in Table 7.

[Comparative Example 2]
A near-infrared reflective film (VI) 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 Comparative Example 1, and the near-infrared reflection is performed on the other surface of the resin substrate. A film (VII) was formed to obtain an optical filter having a thickness of 1.01 mm.

The near-infrared reflective films (VI) and (VII) are not optimized using the optical thin film design software as in Example 1, but the optical filter has the transmittance and reflectance shown in Table 7. The film thickness and the number of layers were designed while confirming the characteristics. The near-infrared reflective film (VI) is formed at a deposition temperature of 100 ° C., and is formed by alternately laminating silica (SiO ₂ ) layers and titanium oxide (TiO ₂ ) layers (6 layers in total). The near-infrared reflective film (VII) is formed at a deposition temperature of 100 ° C., and is formed by alternately laminating silica (SiO ₂ ) layers and titanium oxide (TiO ₂ ) layers (a total of four layers).

The near-infrared reflective film (VI) was a multilayer deposited film having 6 layers, in which a silica layer having a film thickness of 74 to 155 nm and a titanium oxide layer having a film thickness of 83 to 87 nm were alternately stacked. The near-infrared reflective film (VII) was a multi-layer deposited film having 4 layers, in which a silica layer having a thickness of 79 to 164 nm and a titanium oxide layer having a thickness of 89 to 94 nm were alternately stacked. An example of the film configuration is shown in Table 6.

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" (manufactured by 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 In Table 7, the film drying conditions of Examples and Comparative Examples 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 ° C./8 hr
Condition (3): 60 ° C./8 hr → 80 ° C./8 hr → under reduced pressure 100 ° C./24 hr
Condition (4): 40 ° C./4 hr → 60 ° C./4 hr → under reduced pressure 100 ° C./8 hr
In addition, the coating film was peeled from the glass plate before drying under reduced pressure.

As shown in Comparative Example 2, even when the average value of 5 ° reflectance was 70% or more, generation of ghost light was confirmed when the average value of 45 ° reflectance was less than 70%. On the other hand, as shown in each Example, generation of ghost light was not confirmed when the average value of 45 ° reflectance was 70% or more.

Therefore, the optical filter satisfying the above requirements of the present invention is excellent in visible light transmittance and near-infrared cut characteristics, and can suppress the generation of ghost light, and has various characteristics required for solid-state imaging device applications. At the same time, it can be well balanced. 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: Optical filter 2: Spectrophotometer 3: Light 4: Reflection mirror

Claims

A transparent resin substrate;
A near-infrared reflective film formed on at least one surface of the substrate;
An optical filter that satisfies the following requirements (A) to (B):
(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 1200 nm, the average value of the reflectance when measured from one surface side of the optical filter at an angle of 45 ° with respect to the vertical direction of the optical filter is 70% or more.
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 claim 1, wherein the optical filter is at least one resin selected from the group consisting of a series resin and a silsesquioxane resin.
The optical filter according to claim 1 or 2, wherein the transparent resin substrate contains a near-infrared absorbing dye.
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 claim 3, which contains an infrared absorbing dye.
The optical according to claim 3 or 4, 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). filter.

[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 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, 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). ]
In the wavelength region of 800 to 1200 nm, the average reflectance when measured from an angle of 45 ° with respect to the vertical direction of the optical filter is 70% or more when measured from any side of the optical filter. The optical filter according to any one of claims 1 to 5.
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.
The optical filter according to any one of claims 1 to 7, which is used for a solid-state imaging device.
A solid-state imaging device comprising the optical filter according to any one of claims 1 to 7.
A camera module comprising the optical filter according to any one of claims 1 to 7.