Optical filter and UV pigment

Abstract

The present invention relates to an optical filter comprising a substrate and a reflecting layer that is formed from a dielectric multilayer film layered as an outermost layer on at least one principal surface side of the substrate, wherein the substrate has a resin layer, and the resin layer includes a transparent resin, a UV pigment that satisfies all of prescribed characteristics (i-1) through (i-4), and an IR pigment that has a maximum absorption wavelength in the wavelength range of 650-800 nm.

Description

Optical Filters and UV Dyes

[0001] The present invention relates to an optical filter and a UV dye. Specifically, the present invention relates to an optical filter that transmits light in the visible wavelength range and blocks light in the ultraviolet wavelength range and near-infrared wavelength range. The present invention also relates to a novel UV dye that is suitable as a UV dye contained in a resin layer of the optical filter.

[0002] In order to reproduce color tones well and obtain clear images, imaging devices using solid-state imaging elements use optical filters that transmit light in the visible range (hereinafter also referred to as "visible light") and block light in the ultraviolet wavelength range (hereinafter also referred to as "ultraviolet light") and light in the near-infrared wavelength range (hereinafter also referred to as "near-infrared light").

[0003] Known optical filters include, for example, reflective filters that reflect light to be blocked by utilizing optical interference caused by a dielectric multilayer film, which is made by alternately stacking dielectric thin films with different refractive indices on one or both sides of a transparent substrate. Such optical filters vary in optical thickness depending on the angle of incidence of light. Therefore, for example, when light is incident at a high angle of incidence, near-ultraviolet light, which should have a high reflectance, may be transmitted, resulting in light leakage. Because image sensors are sensitive to the near-ultraviolet region, insufficient near-ultraviolet light blocking may result in image quality degradation due to unwanted light, such as flare and ghosting, in captured visible light images. Thus, there is a need for a near-infrared and ultraviolet cut filter that is unlikely to affect the spectral sensitivity of solid-state image sensors depending on the angle of incidence.

[0004] Here, Patent Documents 1 and 2 describe optical filters that have both near-ultraviolet light blocking capabilities and near-infrared light blocking capabilities, which are formed by combining an absorption layer containing a near-ultraviolet light absorbing dye and a near-infrared light absorbing dye in a transparent resin with a dielectric multilayer film.

[0005] Japanese Patent No. 6020746 Japanese Patent No. 6773161

[0006] However, although the optical filters described in Patent Documents 1 and 2 are designed to block near-ultraviolet light up to an incident angle of 30 degrees, there is room for improvement in blocking properties at higher incident angles. By using a UV dye with a maximum absorption wavelength of approximately 400 nm, near-ultraviolet light with a wavelength of approximately 370 nm or greater can be blocked. However, light leakage still occurs in the wavelength range of 350 to 370 nm.

[0007] Therefore, when a conventional UV dye with a maximum absorption wavelength of 350 to 370 nm was used, the absorption of light in this wavelength range was weak, and in order to effectively suppress light leakage, it was necessary to add a large amount of the above UV dye. In addition, the absorption width was broad, and some light in the visible light range, such as the blue band, was also absorbed.

[0008] Therefore, an object of the present invention is to provide an optical filter that has excellent near-infrared and ultraviolet light shielding properties while maintaining high visible light transmittance, and that suppresses flare and ghosting by improving the ability to shield ultraviolet light with a wavelength of 350 to 370 nm in particular.Another object of the present invention is to provide a UV dye that selectively absorbs ultraviolet light with a wavelength of 350 to 370 nm and has excellent light-shielding properties.

[0009] The present invention provides an optical filter having the following configuration, and an imaging device including the optical filter: The optical filter includes a substrate and a reflective layer made of a dielectric multilayer film laminated as an outermost layer on at least one main surface of the substrate, wherein the substrate has a resin layer, and the resin layer includes a transparent resin, a UV dye satisfying all of the following properties (i-1) to (i-4), and an IR dye having a maximum absorption wavelength in the wavelength range of 650 to 800 nm: Property (i-1): having a maximum absorption wavelength in dichloromethane in the wavelength range of 340 to 375 nm Property (i-2): having a molar absorption coefficient in dichloromethane of 3.0 x 10 ４ L / mol cm or more. Characteristic (i-3) The half-width at the maximum absorption wavelength of the characteristic (i-1) is 40 nm or less. Characteristic (i-4) In the spectral transmittance curve measured by dissolving the compound in dichloromethane and adjusting the concentration so that the transmittance at the maximum absorption wavelength of the characteristic (i-1) is 10%, the average transmittance at wavelengths of 350 to 370 nm is 20% or less.

[0010] The present invention also provides a UV dye having the following structure: A UV dye comprising a compound represented by the following formula (I)'.

[0011]

[0012] (In formula (I)′, X′ is an oxygen atom or a sulfur atom, and R １ is an alkyl group having 1 to 6 carbon atoms which may have a substituent, and R ２ ~R ５ are each independently a hydrogen atom, a halogen atom, an alkyl group or alkoxy group having 1 to 10 carbon atoms which may have a substituent, a nitro group, an amino group, or an amide group, and A represents any of the divalent groups represented by the following formulas (A1) to (A4):

[0013]

[0014] In formulas (A1) to (A4), Y is an oxygen atom or a sulfur atom, and R ６ ~R １３ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, or a phenyl group.

[0015] According to the present invention, it is possible to provide an optical filter that maintains high transmittance for visible light while exhibiting excellent near-infrared and ultraviolet light blocking properties, and that suppresses flare and ghosting by improving the blocking properties for ultraviolet light with wavelengths of 350 to 370 nm, and an imaging device equipped with the optical filter.It is also possible to provide a UV dye that is suitable for the optical filter and selectively absorbs ultraviolet light with wavelengths of 350 to 370 nm and exhibits excellent light blocking properties.

[0016] FIG. 1 is a schematic cross-sectional view of an example of an optical filter according to this embodiment. FIG. 2 is a spectral transmittance curve for Example 3-1. FIG. 3 is a spectral transmittance curve for Example 3-8. FIG. 4 is a spectral reflectance curve for the antireflection layer side of the substrate of Example 3-1, which is made of a dielectric multilayer film, at an incident angle of 5 degrees. FIG. 5 is a spectral transmittance curve for Example 4-1, which is made of a dielectric multilayer film, at incident angles of 0 degrees, 30 degrees, and 50 degrees. FIG. 6 is a spectral transmittance curve for Example 4-4, which is made of a dielectric multilayer film, at an incident angle of 0 degrees. FIG. 7 is a spectral reflectance curve for the reflective layer side of the optical filter of Example 4-1, which is made of a dielectric multilayer film, at an incident angle of 5 degrees.

[0017] DETAILED DESCRIPTION OF THE INVENTION In this specification, "IR dye" means an infrared absorbing dye, and "UV dye" means an ultraviolet absorbing dye.

[0018] In this specification, the spectral characteristics can be measured using an ultraviolet-visible-near-infrared spectrophotometer. In this specification, the internal transmittance is the transmittance obtained by subtracting the influence of interface reflection from the actually measured transmittance, which is expressed by the formula {actually measured transmittance / (100-reflectance)}×100. In this specification, the absorbance is expressed as -log １０ It is converted from the (internal) transmittance using the formula ((internal) transmittance / 100). In this specification, when the spectral transmittance is measured when the dye is contained in a transparent resin, all instances where it is referred to as "transmittance" refer to "internal transmittance". On the other hand, the transmittance measured by dissolving the dye in a dichloromethane solvent, the transmittance of the substrate, the transmittance of the dielectric multilayer film, and the transmittance of an optical filter having a dielectric multilayer film are actually measured transmittances. The absorbance and molar absorption coefficient are calculated by converting the obtained transmission spectral curve into an absorbance curve using the following formula. The same applies to the half-width at the maximum absorption wavelength. Absorbance = -log １０ (Transmittance / 100)

[0019] In this specification, a compound represented by formula (I) is referred to as compound (I). The same applies to compounds represented by other formulas. A dye consisting of compound (I) is also referred to as dye (I), and the same applies to other dyes. A group represented by formula (X1) is also referred to as group (X1), and the same applies to groups represented by other formulas. In this specification, alkyl groups include linear, branched, and cyclic alkyl groups. In this specification, the term "to" representing a numerical range is used to mean that the numerical values ​​written before and after it are included as the lower limit and upper limit.

[0020] <<Optical Filter>> The optical filter according to this embodiment (hereinafter also referred to as “the present optical filter”) includes a substrate and a reflective layer made of a dielectric multilayer film laminated as an outermost layer on at least one main surface of the substrate. The substrate includes a resin layer, and the resin layer contains a transparent resin, as well as specific UV dyes and IR dyes.

[0021] With this configuration, the reflective properties of the reflective layer made of the dielectric multilayer film and the absorption properties of the dye in the resin layer enable the optical filter as a whole to achieve excellent shielding properties in the near-ultraviolet and near-infrared regions while maintaining excellent transmittance in the visible light region. In particular, by containing a UV dye with specific properties in the resin layer, it is possible to effectively block ultraviolet light on the short wavelength side, such as wavelengths of 350 to 370 nm, which has traditionally been difficult to prevent from leaking, without impairing transmittance in the visible light region.

[0022] The configuration of an optical filter according to this embodiment will be described with reference to FIG. 1 , which is a schematic cross-sectional view showing one example. The optical filter 1 has a substrate 10 and a reflective layer 20 made of a dielectric multilayer film on at least one main surface of the substrate 10. The dielectric multilayer film that becomes the reflective layer 20 is laminated as the outermost layer of the optical filter 1. In FIG. 1 , the reflective layer 20 is provided only on one main surface of the substrate 10, but it may be provided as the outermost layer on both main surfaces. Note that although FIG. 1 shows the reflective layer 20 as a single layer, it is actually a dielectric multilayer film in which multiple layers made of two or more different types are laminated.

[0023] The substrate 10 only needs to have a resin layer 12, and the resin layer 12 contains a transparent resin and a specific UV dye and an IR dye. The substrate 10 may also have a support 11, if desired. If the resin layer 12 is self-supporting, the resin layer 12 can also serve as a support. When the substrate 10 has a support 11 and a resin layer 12, the resin layer 12 may be formed on one main surface of the support 11 as shown in FIG. 1 , or may be formed on both main surfaces of the support 11 so as to sandwich the support 11 from both sides.

[0024] The substrate 10 may have an antireflection layer 13, and if an antireflection layer 13 is provided, it is preferably laminated as the outermost layer of the optical filter 1, on the side opposite to the reflective layer 20. Although the antireflection layer 13 is shown as a single layer in FIG. 1 , it may also be a dielectric multilayer film in which multiple layers made of two or more different types are laminated. In addition to the above, the optical filter 1 may further have another functional layer, as long as the effects of the present invention are not impaired.

[0025] <Substrate> (Resin Layer) UV Dye (α) The UV dye in this embodiment preferably satisfies all of the following properties (i-1) to (i-4) and further satisfies the following properties (i-5) and (i-6). This UV dye may be referred to as UV dye (α). Property (i-1) It has a maximum absorption wavelength in dichloromethane at a wavelength of 340 to 375 nm. Property (i-2) It has a molar absorption coefficient in dichloromethane of 3.0 × 10 ４ L / mol cm or more. Characteristic (i-3): The half width at the maximum absorption wavelength of the characteristic (i-1) is 40 nm or less. Characteristic (i-4): In a spectral transmittance curve measured by dissolving the sample in dichloromethane and adjusting the concentration so that the transmittance at the maximum absorption wavelength of the characteristic (i-1) is 10%, the average transmittance at wavelengths of 350 to 370 nm is 20% or less. Characteristic (i-5): In a spectral transmittance curve measured by dissolving the sample in dichloromethane and adjusting the concentration so that the transmittance at the maximum absorption wavelength of the characteristic (i-1) is 10%, the minimum transmittance at wavelengths of 400 to 650 nm is 85% or more. Characteristic (i-6): In a spectral transmittance curve measured by dissolving the sample in dichloromethane and adjusting the concentration so that the transmittance at the maximum absorption wavelength of the characteristic (i-1) is 10%, the average transmittance at wavelengths of 350 to 370 nm is 15% or less.

[0026] By satisfying the properties (i-1) and (i-4), it is possible to block ultraviolet light with a wavelength of 350 to 370 nm, which has traditionally been difficult to prevent from causing light leakage, and by further satisfying the property (i-2), it is possible to improve the blocking property, i.e., the light absorption strength. By satisfying the property (i-3) in addition to the properties (i-1), (i-2), and (i-4), it is possible to selectively block ultraviolet light of the desired wavelength and prevent light leakage without impairing the transmittance in the visible light region, where high transmittance is required.

[0027] In the characteristic (i-1), it is sufficient that the maximum absorption wavelength is in the range of 340 to 375 nm, but the maximum absorption wavelength is preferably in the range of 350 to 375 nm or 340 to 370 nm, and more preferably in the range of 350 to 370 nm.

[0028] The molar absorption coefficient of characteristic (i-2) is 3.0 × 10 ４ L / mol cm or more is sufficient, but 3.5 × 10 ４L / mol cm or more is preferable, and 4.0 × 10 ４ The upper limit of the molar absorption coefficient is not particularly limited, but is usually 5.0 × 10 ５ L / mol·cm or less.

[0029] The half-width of characteristic (i-3) is a wavelength range in which the absorbance is equal to or greater than half of the absorbance at the maximum absorption wavelength in dichloromethane between 340 and 375 nm, and is a value that indicates the spread of the absorption peak in the wavelength direction. The half-width may be 40 nm or less, but is preferably 38 nm or less. The lower limit is not particularly limited, but is usually 5 nm or more.

[0030] The average transmittance at wavelengths of 350 to 370 nm as shown in characteristic (i-4) may be 20% or less, but is preferably 15% or less as shown in characteristic (i-6). There is no particular lower limit to the average transmittance, and the smaller the better, but it is usually 0.1% or more.

[0031] In addition to the characteristic (i-3), the minimum transmittance at wavelengths of 400 to 650 nm of the characteristic (i-5) of 85% or more is preferable because it allows the transmittance in the visible light region of 400 to 650 nm, where high transmittance is required, to be maintained without being impaired. The minimum transmittance is more preferably 87.5% or more, even more preferably 90% or more, even more preferably 92.5% or more, and particularly preferably 95% or more. The higher the minimum transmittance, the better, and it may even be 100%.

[0032] As the UV dye (α) that satisfies the above properties (i-1) to (i-4) and preferably further satisfies the above properties (i-5) and (i-6), a compound represented by the following formula (I) is preferred.

[0033]

[0034] (In formula (I), X represents an oxygen atom, a sulfur atom, or an N—R １４ , or C-R １５ R １６ (R １４ ~R １６ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms which may have a substituent, and R １is an alkyl group having 1 to 6 carbon atoms which may have a substituent, and R ２ ~R ５ are each independently a hydrogen atom, a halogen atom, an alkyl group or alkoxy group having 1 to 10 carbon atoms which may have a substituent, a nitro group, an amino group, or an amide group, and A represents any of the divalent groups represented by the following formulas (A1) to (A4):

[0035]

[0036] In formulas (A1) to (A4), Y is an oxygen atom or a sulfur atom, and R ６ ~R １３ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, or a phenyl group.

[0037] In compound (I), X is an oxygen atom, a sulfur atom, or N—R １４ , or C-R １５ R １６ It is. １４ ~R １６ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms which may have a substituent, and examples of the substituent include an alkoxy group, an acyl group, an acyloxy group, a cyano group, a dialkylamino group, or a chlorine atom. １４ ~R １６ are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms which may have a substituent. X is an oxygen atom, a sulfur atom, or C—R １５ R １６ is preferred, and an oxygen atom or a sulfur atom is more preferred. That is, compound (I) is more preferably a compound represented by the following formula (I)'.

[0038]

[0039] (In formula (I)′, X′ is an oxygen atom or a sulfur atom, and R １ is an alkyl group having 1 to 6 carbon atoms which may have a substituent, and R ２ ~R ５are each independently a hydrogen atom, a halogen atom, an alkyl group or alkoxy group having 1 to 10 carbon atoms which may have a substituent, a nitro group, an amino group, or an amide group, and A represents any of the divalent groups represented by the above formulas (A1) to (A4).

[0040] In compound (I) or compound (I)′, R １ R is an alkyl group having 1 to 6 carbon atoms which may have a substituent. Examples of the substituent which may have include an alkoxy group, an acyl group, an acyloxy group, a cyano group, a dialkylamino group, and a chlorine atom. １ is preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and even more preferably a methyl group.

[0041] In compound (I) or compound (I)′, R ２ ~R ５ are each independently a hydrogen atom, a halogen atom, an alkyl group or alkoxy group having 1 to 10 carbon atoms which may have a substituent, a nitro group, an amino group, or an amido group. Examples of the substituent which may have include an alkoxy group, an acyl group, an acyloxy group, a cyano group, a dialkylamino group, or a chlorine atom. ２ is preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom, and more preferably a hydrogen atom. ３ is preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. ４ is preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom, and more preferably a hydrogen atom. ５ is preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom, and more preferably a hydrogen atom.

[0042] In compound (I) or compound (I)′, A represents any one of the divalent groups represented by the above formulae (A1) to (A4), and preferably a divalent group represented by formula (A1) or (A3).

[0043] In the divalent group represented by formula (A1), Y is an oxygen atom or a sulfur atom. When X in formula (I) or X' in formula (I)' is a sulfur atom, Y is preferably an oxygen atom. When Y is a sulfur atom, X is preferably an oxygen atom, N-R １４ , or C-R １５ R １６ is preferable, and an oxygen atom is more preferable, and X' is preferably an oxygen atom. Also, at least one of X or X' and Y is preferably an oxygen atom.

[0044] In the divalent groups represented by formulae (A1) to (A4), R ６ ~R １３ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, or a phenyl group. Examples of the substituent which may have include an alkoxy group, an acyl group, an acyloxy group, a cyano group, a dialkylamino group, or a chlorine atom. ６ and R ７ are each independently preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group, more preferably an alkyl group having 1 to 6 carbon atoms. ８ and R ９ are each independently preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group, more preferably an alkyl group having 1 to 6 carbon atoms. １０ and R １１ are each independently preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group, more preferably an alkyl group having 1 to 6 carbon atoms. １２ and R １３ are each independently preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom.

[0045] More specifically, compound (I) or compound (I)' includes compounds in which the atoms or groups bonded to each skeleton are shown in the following Table 1. In the table, i-Bu means an isobutyl group, t-Bu means a tertiary butyl group, and Ph means a phenyl group.

[0046]

[0047] Among the above, the compounds having dye abbreviations I-1, I-2, I-3, and I-8 are particularly preferred. Note that the resin layer in this embodiment may contain one UV dye (α) having the above properties, but this does not exclude the inclusion of two or more types.

[0048] The method for producing compound (I) or compound (I)′ is not particularly limited, but for example, 2-(methylthio)benzothiazole is reacted with methyl p-toluenesulfonate to obtain intermediate 1 represented by the following formula: In the formula, Ts represents a tosyl group.

[0049]

[0050] The compound (I) or compound (I)' can be obtained by reacting the intermediate 1 with a compound corresponding to the divalent group represented by formula (A1) to (A4) in the presence of a solvent. １ ~R ５ or a 2-(methylthio)benzoxazole or 2-(methylthio)indole derivative, etc., where the hydrogen atom corresponding to the formula (I) is substituted with a substituent, thereby obtaining a compound (I) or compound (I)' having the desired structure.

[0051] UV dye (β) In addition to the UV dye (α) having the above-described properties, the resin layer in this embodiment may contain another UV dye (β). The UV dye (β) may have one to three of the properties (i-1) to (i-4) of the UV dye (α), or may not have any of the properties (i-1) to (i-4).

[0052] From the viewpoint of blocking the entire ultraviolet light region, such as wavelengths of 350 to 400 nm, when used in combination with the UV dye (α), the UV dye (β) preferably has a maximum absorption wavelength different from that of the UV dye (α), more preferably has a maximum absorption wavelength on the longer wavelength side than the maximum absorption wavelength of the UV dye (α), and further preferably has a maximum absorption wavelength in the wavelength range of 370 to 405 nm.

[0053] The difference in maximum absorption wavelength between the UV dye (α) and the UV dye (β) is more preferably 15 nm or more, and even more preferably 20 nm or more. From the viewpoint of blocking the entire ultraviolet light region, the upper limit of the difference in maximum absorption wavelength is more preferably 60 nm or less.

[0054] More specifically, the UV dye (β) is preferably a merocyanine dye represented by the following formula (M).

[0055]

[0056] In formula (M), R ２１ represents a monovalent hydrocarbon group having 1 to 12 carbon atoms, which may have a substituent. The substituent is preferably an alkoxy group, an acyl group, an acyloxy group, a cyano group, a dialkylamino group, or a chlorine atom. The alkoxy group, acyl group, acyloxy group, and dialkylamino group preferably have 1 to 6 carbon atoms.

[0057] Preferred R ２１ is an alkyl group having 1 to 6 carbon atoms in which some of the hydrogen atoms may be substituted with a cycloalkyl group or a phenyl group. ２１ is an alkyl group having 1 to 6 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a t-butyl group.

[0058] R ２２ ~R ２５ each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms. The alkyl group and alkoxy group preferably have 1 to 6 carbon atoms, and more preferably 1 to 4 carbon atoms.

[0059] R ２２ and R ２３ At least one of R is preferably an alkyl group, and more preferably both are alkyl groups. ２２ and R ２３ When R is not an alkyl group, a hydrogen atom is more preferred. ２２ and R ２３ is particularly preferably an alkyl group having 1 to 6 carbon atoms.

[0060] R ２４ and R２５ At least one of R is preferably a hydrogen atom, and more preferably both are hydrogen atoms. ２４ and R ２５ When is not a hydrogen atom, it is preferably an alkyl group having 1 to 6 carbon atoms.

[0061] Y ２０ is R ２６ and R ２７ represents a methylene group or an oxygen atom substituted with R ２６ and R ２７ each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms.

[0062] X ２０ represents any one of the divalent groups represented by the following formulas (X1) to (X5).

[0063]

[0064] R ２８ and R ２９ each independently represents a monovalent hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, R ３０ ~R ３９ R each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms which may have a substituent. ２８ ~R ３９ The substituents of R ２１ The same substituents as those in the group R are mentioned, and the preferred embodiments are also the same. ２８ ~R ３９ is a hydrocarbon group having no substituents, R ２１ The same aspects as above can be mentioned.

[0065] Preferred R ２８ and R ２９ are all alkyl groups having 1 to 6 carbon atoms in which some of the hydrogen atoms may be substituted with cycloalkyl groups or phenyl groups. Particularly preferred R ２８ and R ２９ are all alkyl groups having 1 to 6 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a t-butyl group.

[0066] In formula (X2), R ３０ and R ３１ are more preferably alkyl groups having 1 to 6 carbon atoms, and it is particularly preferred that they are the same alkyl groups.

[0067] In formula (X3), R ３２ and R ３５ are preferably both hydrogen atoms or unsubstituted alkyl groups having 1 to 6 carbon atoms. ３３ and R ３４ are preferably all hydrogen atoms or all alkyl groups having 1 to 6 carbon atoms.

[0068] In formula (X4), two groups R bonded to the same carbon atom ３６ and R ３７ and R ３８ and R ３９ are preferably all hydrogen atoms or all alkyl groups having 1 to 6 carbon atoms.

[0069] The compound represented by formula (M) includes Y ２０ is an oxygen atom, and X ２０ is a group (X1), a group (X2) or a group (X5), and ２０ is an unsubstituted methylene group, and X ２０ is a group (X1), a group (X2) or a group (X5).

[0070] Specific examples of the compound (M) include the compounds shown in the table below.

[0071]

[0072] As the compound (M), the compounds (M-2), (M-8), (M-9), (M-13) and (M-20) are preferred in terms of their solubility in transparent resins and appropriate maximum absorption wavelengths.

[0073] Compound (M) can be produced by a known method, for example, as described in Japanese Patent No. 6,504,176.

[0074] The total content of the UV dye (α) and the UV dye (β) in the resin layer is preferably in a range such that the product of the total content of the UV dye (α) and the UV dye (β) expressed in mass % and the thickness of the resin layer is 20.0 (mass % μm) or less, more preferably 19.0 (mass % μm) or less, and particularly preferably 18.0 (mass % μm) or less. By setting the total amount of the UV dye (α) and the UV dye (β) added within the above range, deterioration of the resin properties can be prevented and good adhesion with the dielectric multilayer film and the support can be maintained. Furthermore, deterioration of heat resistance due to a decrease in the glass transition temperature of the transparent resin can be suppressed. Furthermore, from the viewpoint of achieving the desired spectral characteristics, the product is preferably 3.0 (mass % μm) or more, more preferably 5.0 (mass % μm) or more. When the UV dye (α) is used alone, the product of the total content of the UV dye (α) expressed in mass % and the thickness of the resin layer is also preferably in the same range as above.

[0075] From the viewpoint of ensuring that the product of the total content of the UV dye (α) and the UV dye (β) and the thickness of the resin layer satisfies the above range, the content of the UV dye (α) in the resin layer is preferably 2.0 parts by mass or more, more preferably 3.0 parts by mass or more, and is preferably 15.0 parts by mass or less, more preferably 14.0 parts by mass or less, relative to 100 parts by mass of the transparent resin.

[0076] For the same reason, when the UV dye (β) is contained, the content of the UV dye (β) in the resin layer is preferably 2.0 parts by mass or more, more preferably 3.0 parts by mass or more, relative to 100 parts by mass of the transparent resin, and is preferably 13.0 parts by mass or less, more preferably 12.0 parts by mass or less.

[0077] The total content of the UV dye (α) and the UV dye (β) in the resin layer is preferably 4.0 parts by mass or more, more preferably 5.0 parts by mass or more, and is preferably 15.0 parts by mass or less, more preferably 14.0 parts by mass or less, relative to 100 parts by mass of the transparent resin.

[0078] IR Dye The IR dye contained in the resin layer in this embodiment is a dye having a maximum absorption wavelength of 650 to 800 nm. By including the IR dye, infrared light can be effectively blocked.

[0079] The IR dye is preferably at least one selected from the group consisting of squarylium dyes, cyanine dyes, phthalocyanine dyes, naphthalocyanine dyes, dithiol metal complex dyes, azo dyes, polymethine dyes, phthalide dyes, naphthoquinone dyes, anthraquinone dyes, indophenol dyes, pyrylium dyes, thiopyrylium dyes, chlorokonium dyes, tetradehydrocoline dyes, triphenylmethane dyes, aminium dyes, and diimmonium dyes, and more preferably at least one dye selected from the group consisting of squarylium dyes, phthalocyanine dyes, and cyanine dyes. Among these IR dyes, squarylium dyes and cyanine dyes are preferred from the viewpoint of spectral properties, and phthalocyanine dyes are preferred from the viewpoint of durability.

[0080] The content of the IR dye in the resin layer is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, and is preferably 25 parts by mass or less, more preferably 20 parts by mass or less, per 100 parts by mass of the transparent resin.

[0081] Transparent Resin The transparent resin contained in the resin layer in this embodiment is not particularly limited as long as it is a transparent resin that transmits visible light with a wavelength of 400 to 700 nm.

[0082] Examples of transparent resins include polyester resins, acrylic resins, epoxy resins, ene-thiol resins, polycarbonate resins, polyether resins, polyarylate resins, polysulfone resins, polyethersulfone resins, polyparaphenylene resins, polyarylene ether phosphine oxide resins, polyamide resins, polyimide resins, polyamideimide resins, polyolefin resins, cyclic olefin resins, polyurethane resins, and polystyrene resins. These transparent resins may be used alone or in combination of two or more. Among these, polyimide resins are preferred from the viewpoints of excellent visible light transmittance, a high glass transition temperature of the resin, and resistance to thermal degradation of the dye.

[0083] When the transparent resin has self-supporting properties, the transparent resin can also serve as a support, which will be described later. In this case, the substrate in this embodiment has a single-layer structure of a resin layer, or a multi-layer structure further including an anti-reflection layer on one main surface of the resin layer.

[0084] The entire resin layer The optical filter may have one resin layer or two or more resin layers. When the optical filter has two or more resin layers, the resin layers may have the same or different configurations.

[0085] The thickness of the resin layer is preferably 3 μm or less, more preferably 2.5 μm or less, from the viewpoint of obtaining a uniform film with a small film thickness distribution. Furthermore, the thickness of the resin layer is preferably 0.5 μm or more, more preferably 1 μm or more, from the viewpoint of obtaining desired spectral characteristics. When the optical filter according to this embodiment includes two or more resin layers, it is preferable that the thickness of each resin layer satisfies the above range.

[0086] It is more preferable that the resin layer satisfies all of the following characteristics (iv-1) to (iv-6). However, it is not essential that all of the following characteristics be satisfied. Characteristic (iv-1) An average internal transmittance (D) at a wavelength of 350 to 370 nm is 23% or less. Characteristic (iv-2) An average internal transmittance (E) at a wavelength of 400 to 440 nm is 50% or more. Characteristic (iv-3) The average internal transmittances (D) and (E) satisfy the relationship {(E) / (D)}≧4.0. Characteristic (iv-4) An average internal transmittance (F) at a wavelength of 440 to 500 nm is 90% or more. Characteristic (iv-5) An internal transmittance T at a wavelength of 700 nm is 100% or more. ７００ Characteristic (iv-6) In the spectral internal transmittance curve for wavelengths of 600 to 700 nm, the wavelength IR50 at which the internal transmittance is 50% is in the range of 610 to 670 nm.

[0087] When the resin layer satisfies the above properties (iv-1) to (iv-6), an optical filter can be obtained that has high light-shielding properties in the near-ultraviolet light region and does not lose its ultraviolet light-shielding properties even at high incident angles. In order to satisfy the above properties (iv-1) to (iv-6), for example, the resin layer may contain the above-mentioned UV dye (α) and IR dye, and it is also preferable to use a resin layer that further contains the UV dye (β).

[0088] The average internal transmittance (D) of the characteristic (iv-1) at wavelengths of 350 to 370 nm is 23% or less, preferably 20% or less, and the smaller the better, but is usually 1% or more.

[0089] The average internal transmittance (E) of the characteristic (iv-2) at wavelengths of 400 to 440 nm is 50% or more, more preferably 52% or more, and the higher the better, but is usually 90% or less.

[0090] The ratio of the average internal transmittances (D) and (E) {(E) / (D)} in the characteristic (iv-3) is 4.0 or more, and more preferably 4.3 or more. The upper limit of this ratio is not particularly limited, but is usually 50 or less.

[0091] The average internal transmittance (F) of the characteristic (iv-4) at wavelengths of 440 to 500 nm is 90% or more, more preferably 92% or more, and the higher the better, and it may be 100%.

[0092] Internal transmittance T at a wavelength of 700 nm of characteristic (iv-5) ７００ is 5% or less, preferably 4.5% or less, and the lower the better, but is usually 0.1% or more.

[0093] In the spectral internal transmittance curve of characteristic (iv-6) for wavelengths of 600 to 700 nm, the wavelength IR50 at which the internal transmittance becomes 50% is in the range of 610 to 670 nm, and more preferably in the range of 620 to 670 nm.

[0094] (Support) The resin layer in this embodiment may or may not have a support. The support is not particularly limited and may be an organic or inorganic material as long as it is a self-supporting, transparent material that transmits visible light of 400 to 700 nm. Furthermore, even if the transparent resin contained in the resin layer is self-supporting, a separate support may be provided.

[0095] When a support made of an organic material is used, for example, the transparent resins exemplified above can be used, and when a support made of an inorganic material is used, for example, glass or a crystalline material is preferred.

[0096] As the transparent inorganic material, glass or crystalline material is preferred. Examples of glass that can be used for the support include absorption-type glass containing copper ions in fluorophosphate-based glass or phosphate-based glass, i.e., near-infrared absorbing glass, soda-lime glass, borosilicate glass, alkali-free glass, quartz glass, etc. It is preferable to use an absorption glass according to the purpose, and for example, from the viewpoint of absorbing infrared light, phosphate-based glass and fluorophosphate-based glass are preferred. When it is desired to transmit a large amount of red light with a wavelength of 600 to 700 nm, alkali glass, alkali-free glass, and quartz glass are preferred. Note that the phosphate-based glass has a structure in which part of the glass skeleton is made of SiO ２ Also included is silicophosphate glass composed of: Chemically strengthened glass may also be used.

[0097] Examples of crystalline materials that can be used for the support include birefringent crystals such as quartz, lithium niobate, and sapphire.

[0098] As the support, inorganic materials are preferred, and glass and sapphire are particularly preferred, from the viewpoint of shape stability related to long-term reliability of optical properties, mechanical properties, etc., and ease of handling during filter production.

[0099] (Antireflection Layer) The substrate in this embodiment may have an antireflection layer on one of its outermost layers. The antireflection layer means a layer that does not have a wavelength band with a width of 100 nm or more where the reflectance is 90% or more in a spectral reflectance curve for a wavelength of 750 to 1200 nm and an incident angle of 5 degrees.

[0100] Examples of antireflection layers include dielectric multilayer films, intermediate refractive index media, and moth-eye structures in which the refractive index changes gradually. Among these, dielectric multilayer films are preferred from the viewpoints of optical efficiency and productivity. The dielectric multilayer film is a multilayer film in which low-refractive-index dielectric films, called low-refractive-index films, and high-refractive-index dielectric films, called high-refractive-index films, are alternately stacked, and conventionally known dielectric multilayer films can be used.

[0101] The thickness of the antireflection layer is preferably 0.1 μm or more, more preferably 0.2 μm or more, from the viewpoint of optical properties, and is preferably 1.5 μm or less, more preferably 1.0 μm or less, from the viewpoint of productivity.

[0102] (Entire substrate) The substrate in this embodiment preferably satisfies all of the following characteristics (ii-1) to (ii-6). However, it is not essential that all of the following characteristics be satisfied. Characteristic (ii-1) Average transmittance (A) at wavelengths of 350 to 370 nm is 15% or less Characteristic (ii-2) Average transmittance (B) at wavelengths of 400 to 440 nm is 48% or more Characteristic (ii-3) The average transmittances (A) and (B) satisfy the relationship {(B) / (A)}≧6.0 Characteristic (ii-4) Average transmittance (C) at wavelengths of 440 to 500 nm is 88% or more Characteristic (ii-5) Transmittance T at a wavelength of 700 nm ７００ Characteristic (ii-6) In the spectral transmittance curve for wavelengths of 600 to 700 nm, the wavelength IR50 at which the transmittance is 50% is in the range of 610 to 670 nm.

[0103] By satisfying the above properties (ii-1) to (ii-6), an optical filter can be obtained that has excellent near-infrared and ultraviolet light blocking properties while maintaining high visible light transmittance. In order to satisfy the above properties (ii-1) to (ii-6), for example, a resin layer containing the above-mentioned UV dye (α) and IR dye may be used, and it is also preferable to use a resin layer that further contains a UV dye (β).

[0104] The average transmittance (A) of the characteristic (ii-1) at wavelengths of 350 to 370 nm is 15% or less, preferably 13% or less, and the smaller the better, but is usually 1% or more.

[0105] The average transmittance (B) of the characteristic (ii-2) at wavelengths of 400 to 440 nm is 48% or more, more preferably 50% or more, and the higher the better, but it is usually 90% or less.

[0106] The ratio of the average transmittances (A) and (B) {(B) / (A)} in the characteristic (ii-3) is 6.0 or more, and more preferably 6.5 or more. The upper limit of this ratio is not particularly limited, but is usually 50 or less.

[0107] The average transmittance (C) of the characteristic (ii-4) at wavelengths of 440 to 500 nm is 88% or more, more preferably 89% or more, and the higher the better, and it may even be 100%.

[0108] Transmittance T at a wavelength of 700 nm of characteristic (ii-5) ７００ is 5% or less, more preferably 4% or less, and even more preferably 3% or less, and the lower the better, but is usually 0.1% or more.

[0109] In the spectral transmittance curve of characteristic (ii-6) for wavelengths of 600 to 700 nm, the wavelength IR50 at which the transmittance is 50% is in the range of 610 to 670 nm, more preferably 620 to 670 nm, and even more preferably 630 to 670 nm.

[0110] The thickness of the substrate is preferably 50 μm or more, more preferably 70 μm or more, from the viewpoint of suppressing warping and deformation when a reflective layer made of a dielectric multilayer film is formed, and from the viewpoint of handleability. The upper limit is not particularly limited, but is preferably, for example, 300 μm or less. When the resin layer also serves as a support, the thickness of the substrate is more preferably 120 μm or less, from the viewpoint of the advantage of reducing the height. When a separate support is provided in addition to the resin layer, the thickness of the substrate is more preferably 110 μm or less. The shape of the substrate is not particularly limited, and may be, for example, a block, plate, or film shape.

[0111] <Reflective Layer> The reflective layer of the optical filter according to this embodiment is made of a dielectric multilayer film laminated as an outermost layer on at least one main surface of the substrate. The reflective layer refers to a layer having a wavelength band of 100 nm or more in which the reflectance is 90% or more on a spectral reflectance curve for a wavelength of 750 to 1200 nm and an incident angle of 5 degrees.

[0112] The reflective layer preferably has wavelength selectivity that transmits visible light and mainly reflects light in the near-infrared region other than the light-shielding region of the resin layer. The reflective region of the reflective layer may include the light-shielding region of the resin layer in the near-infrared region. The reflective layer is not limited to the above-mentioned reflective characteristics for the wavelength range of 750 to 1200 nm, and may be appropriately designed to further block light in wavelength regions other than the near-infrared region, for example, the near-ultraviolet region.

[0113] The reflective layer is composed of a dielectric multilayer film in which low-refractive-index films and high-refractive-index films are alternately laminated. The refractive index of the high-refractive-index film is preferably 1.6 or more, more preferably 2.2 or more, and is preferably 2.5 or less. Examples of materials for the high-refractive-index film include Ta. ２ O ５ , TiO ２ , Nb ２ O ５ Among these, TiO is preferred from the viewpoints of film-forming property, reproducibility in refractive index, stability, etc. ２ is preferred.

[0114] The refractive index of the low refractive index film is preferably less than 1.6, more preferably less than 1.55, and more preferably 1.45 or more. Examples of the material for the low refractive index film include SiO. ２ , SiO ｘ N ｙ From the viewpoints of reproducibility, stability, and economy in film formation, SiO ２ is preferred.

[0115] It is preferable that the reflective layer exhibits a steep change in transmittance in the boundary wavelength region between the transmission region and the light blocking region. To achieve this steep change, the total number of laminated dielectric multilayer films constituting the reflective layer is preferably 15 or more, more preferably 25 or more, and even more preferably 30 or more. On the other hand, from the viewpoint of preventing the occurrence of warping or an increase in film thickness, the total number of laminated layers is preferably 100 or less, more preferably 75 or less, and even more preferably 60 or less. The total thickness of the reflective layer is preferably 2 μm or more, and preferably 10 μm or less.

[0116] The dielectric multilayer film can be formed by, for example, a vacuum film-forming process such as chemical vapor deposition (CVD), sputtering, or vacuum deposition, or a wet film-forming process such as spraying or dipping.

[0117] The reflective layer may be one layer, i.e., one group of dielectric multilayer films, that imparts predetermined optical properties, or two or more layers that impart predetermined optical properties. When there are two or more reflective layers, i.e., two or more groups of dielectric multilayer films, the reflective layers may have the same or different configurations. When there are two or more reflective layers, it is preferable that they are composed of multiple reflective layers with different reflection bands. For example, a configuration may be used in which a near-infrared reflective layer that blocks light in the short wavelength band of the near-infrared region is combined with a near-infrared / near-ultraviolet reflective layer that blocks light in both the long wavelength band of the near-infrared region and the near-ultraviolet region.

[0118] <Other Functional Layers> The optical filter according to this embodiment may further include functional layers having other functions as other components, provided that the effects of the present invention are not impaired. Examples of other functional layers include functional layers that provide absorption using inorganic fine particles that control the transmission and absorption of light in a specific wavelength range. Examples of the inorganic fine particles include indium tin oxide (ITO), antimony-doped tin oxide (ATO), cesium tungstate, and lanthanum boride. ITO fine particles and cesium tungstate fine particles have high visible light transmittance and light absorption over a wide range of infrared wavelengths exceeding 1200 nm, and therefore can be used when such infrared light blocking is required.

[0119] <Optical Filter Overall> The optical filter according to this embodiment preferably satisfies all of the following characteristics (iii-1) to (iii-5). However, it is not essential that all of the following characteristics be satisfied. Characteristic (iii-1) Transmittance T at a wavelength of 700 nm and an incident angle of 0 degrees ７００Characteristic (iii-2) In the spectral transmittance curve for wavelengths of 600 to 700 nm, the wavelength IR50 at which transmittance is 50% varies by 4 nm between an incident angle of 0 degrees and an incident angle of 30 degrees. Characteristic (iii-3) The average transmittance for wavelengths of 350 to 370 nm is 0.5% or less at an incident angle of 0 degrees, 0.5% or less at an incident angle of 30 degrees, and 0.5% or less at an incident angle of 50 degrees. Characteristic (iii-4) The maximum transmittance for wavelengths of 350 to 370 nm is 5% or less at an incident angle of 0 degrees, 5% or less at an incident angle of 30 degrees, and 5% or less at an incident angle of 50 degrees. Characteristic (iii-5) The average transmittance for wavelengths of 440 to 500 nm is 88% or more at an incident angle of 0 degrees.

[0120] By satisfying the above properties (iii-1) to (iii-5), an optical filter having excellent near-infrared and ultraviolet light blocking properties while maintaining high visible light transmittance can be obtained. In order to satisfy the above properties (iii-1) to (iii-5), for example, it is sufficient to have a reflective layer made of a resin layer containing the above-mentioned UV dye (α) and IR dye and a dielectric multilayer film. Furthermore, it is also preferable to use a resin layer containing the UV dye (β) or to provide an anti-reflection film.

[0121] Transmittance T at an incident angle of 0 degrees at a wavelength of 700 nm of characteristic (iii-1) ７００ is 1% or less, but is more preferably 0.8% or less, the lower the better, and may be 0%.

[0122] In the spectral transmittance curve of characteristic (iii-2) for wavelengths of 600 to 700 nm, the amount of variation of the wavelength IR50 at which the transmittance is 50% between an incident angle of 0 degree and an incident angle of 30 degrees is 4 nm or less, more preferably 3.5 nm or less, and even more preferably 3 nm or less. The lower limit of the amount of variation is not particularly limited, but is usually 0.5 nm or more.

[0123] The average transmittance of the characteristic (iii-3) at a wavelength of 350 to 370 nm is 0.5% or less at an incident angle of 0 degree, 0.5% or less at an incident angle of 30 degrees, and 0.5% or less at an incident angle of 50 degrees. However, the average transmittance is more preferably 0.4% or less at any incident angle, and even more preferably 0.3% or less. The smaller the better, but is usually 0.01% or more.

[0124] The maximum transmittance at wavelengths of 350 to 370 nm, which is characteristic (iii-4), is 5% or less at an incident angle of 0 degrees, 5% or less at an incident angle of 30 degrees, and 5% or less at an incident angle of 50 degrees. The maximum transmittance is more preferably 4.5% or less at any incident angle, and the smaller the better, but is usually 0.1% or more.

[0125] The average transmittance of the characteristic (iii-5) in the wavelength range of 440 to 500 nm is 88% or more at an incident angle of 0 degree, more preferably 89% or more, even more preferably 92% or more, particularly preferably 94% or more, and the higher the better, and it may even be 100%.

[0126] The optical filter according to the present embodiment, when used in an imaging device such as a digital still camera, can provide an imaging device with excellent color reproducibility. That is, the imaging device according to the present embodiment preferably includes the optical filter, and more specifically, includes a solid-state imaging element, an imaging lens, and the optical filter. The optical filter can be used, for example, by being disposed between the imaging lens and the solid-state imaging element, or by being directly attached to the solid-state imaging element, imaging lens, etc. of the imaging device via an adhesive layer.

[0127] <Method for manufacturing optical filter> The resin layer in the optical filter according to this embodiment is prepared by dissolving or dispersing a transparent resin or its raw material components, a UV dye (α), an IR dye, and optionally a UV dye (β) and other components in a solvent to prepare a coating solution. This is applied to a sheet, heated, and cured to form a resin layer. By peeling the sheet from the obtained resin layer, a substrate consisting of only the resin layer is obtained. Furthermore, if the support according to this embodiment is used for the sheet, a substrate consisting of the support and the resin layer is obtained.

[0128] The solvent in the coating solution may be any dispersion medium in which each component can be stably dispersed or dissolved. The coating solution may also contain a surfactant to prevent voids caused by minute bubbles, depressions caused by the adhesion of foreign matter, and repellency during the drying process.

[0129] The coating liquid can be applied by, for example, dip coating, cast coating, spin coating, etc. Curing is carried out by a curing treatment such as heat curing or photocuring.

[0130] When the substrate does not include a support, the resin layer may be produced in the form of a film by extrusion molding. When the substrate includes a support, the resin layer obtained above may be integrated with the support by thermocompression bonding or the like.

[0131] In addition to the above, if desired, an anti-reflection layer may be further formed on the substrate.

[0132] The optical filter according to the present embodiment can be obtained by forming a reflective layer made of a dielectric multilayer film as an outermost layer on at least one of the main surfaces of the obtained substrate. If desired, other functional layers may also be formed on the optical filter.

[0133] <<UV Dye>> The UV dye according to this embodiment is a compound represented by the following formula (I)′.

[0134]

[0135] (In formula (I)′, X′ is an oxygen atom or a sulfur atom, and R １ is an alkyl group having 1 to 6 carbon atoms which may have a substituent, and R ２ ~R ５ are each independently a hydrogen atom, a halogen atom, an alkyl group or alkoxy group having 1 to 10 carbon atoms which may have a substituent, a nitro group, an amino group, or an amide group, and A represents any of the divalent groups represented by the following formulas (A1) to (A4):

[0136]

[0137] In formulas (A1) to (A4), Y is an oxygen atom or a sulfur atom, and R ６ ~R １３ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, or a phenyl group.

[0138] Preferred embodiments of compound (I)' are the same as those described above in the <<Substrate>>, (Resin Layer) and UV Dye (α) of <<Optical Filter>>.

[0139] The optical filter, imaging device, and UV dye according to this embodiment have been described in detail above, but another aspect of the optical filter and imaging device according to this embodiment is as follows. [1] An optical filter comprising a substrate and a dielectric multilayer film laminated as an outermost layer on at least one main surface side of the substrate, wherein the substrate has a resin layer, and the resin layer includes a transparent resin, a UV dye that satisfies all of the following properties (i-1) to (i-4), and an IR dye that has a maximum absorption wavelength in the range of 650 to 800 nm: Property (i-1) having a maximum absorption wavelength in dichloromethane at a wavelength of 340 to 375 nm Property (i-2) having a molar absorption coefficient in dichloromethane of 3.0 x 10 ４ [1] The optical filter according to [1] above, wherein the UV dye further satisfies the following characteristic (i-5): L / mol cm or more. [2] The optical filter according to [1] above, wherein the UV dye further satisfies the following characteristic (i-6): L / mol cm or more. [3] The optical filter according to [1] above, wherein the UV dye further satisfies the following characteristic (i-7): L / mol cm or more. [4] The optical filter according to [1] above, wherein the UV dye further satisfies the following characteristic (i-8): L / mol cm or more. [5] The optical filter according to [1] above, wherein the UV dye further satisfies the following characteristic (i-9): L / mol cm or more. [6] The optical filter according to [1] above, wherein the UV dye further satisfies the following characteristic (i-1): L / mol cm or more. Characteristic (i-6): In a spectral transmittance curve measured by dissolving the compound in dichloromethane and adjusting the concentration so that the transmittance at the maximum absorption wavelength of the characteristic (i-1) is 10%, the average transmittance at wavelengths of 350 to 370 nm is 15% or less. [4] The optical filter according to any one of the above [1] to [3], wherein the UV dye is a compound represented by the following formula (I):

[0140]

[0141] (In formula (I), X represents an oxygen atom, a sulfur atom, or an N—R １４ , or C-R １５ R １６ (R １４ ~R １６ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms which may have a substituent, and R １ is an alkyl group having 1 to 6 carbon atoms which may have a substituent, and R ２ ~R ５ are each independently a hydrogen atom, a halogen atom, an alkyl group or alkoxy group having 1 to 10 carbon atoms which may have a substituent, a nitro group, an amino group, or an amide group, and A represents any of the divalent groups represented by the following formulas (A1) to (A4):

[0142]

[0143] In formulas (A1) to (A4), Y is an oxygen atom or a sulfur atom, and R ６ ~R １３ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, or a phenyl group.

[0144] [5] The optical filter according to [4], wherein in the compound represented by formula (I), X is an oxygen atom or a sulfur atom. [6] The optical filter according to [4] or [5], wherein in the compound represented by formula (I), A is a divalent group represented by formula (A1) or (A3). [7] The optical filter according to any one of [4] to [6], wherein in the compound represented by formula (I), A is a divalent group represented by formula (A1), and at least one of X and Y is an oxygen atom. [8] The optical filter according to any one of [1] to [7], wherein the IR dye is at least one dye selected from the group consisting of squarylium dyes, phthalocyanine dyes, and cyanine dyes. [9] The optical filter according to any one of [1] to [8], wherein the substrate satisfies all of the following properties (ii-1) to (ii-6): Characteristic (ii-1) The average transmittance (A) at a wavelength of 350 to 370 nm is 15% or less. Characteristic (ii-2) The average transmittance (B) at a wavelength of 400 to 440 nm is 48% or more. Characteristic (ii-3) The average transmittances (A) and (B) satisfy the relationship {(B) / (A)}≧6.0. Characteristic (ii-4) The average transmittance (C) at a wavelength of 440 to 500 nm is 88% or more. Characteristic (ii-5) The transmittance T at a wavelength of 700 nm ７００

[10] The optical filter according to any one of [1] to [9], which satisfies all of the following properties (iii-1) to (iii-5): Property (iii-1) Transmittance T at a wavelength of 700 nm at an incident angle of 0 degrees: ７００Characteristic (iii-2) In a spectral transmittance curve for wavelengths of 600 to 700 nm, the wavelength IR50 at which the transmittance is 50% varies by 4 nm or less between an incident angle of 0 degree and an incident angle of 30 degrees. Characteristic (iii-3) The average transmittance for wavelengths of 350 to 370 nm is 0.5% or less at an incident angle of 0 degree, 0.5% or less at an incident angle of 30 degrees, and 0.5% or less at an incident angle of 50 degrees. Characteristic (iii-4) The maximum transmittance for wavelengths of 350 to 370 nm is 5% or less at an incident angle of 0 degree, 5% or less at an incident angle of 30 degrees, and 5% or less at an incident angle of 50 degrees. Characteristic (iii-5) The average transmittance for wavelengths of 440 to 500 nm is 88% or more at an incident angle of 0 degree.

[11] An imaging device comprising the optical filter according to any one of the above [1] to

[10] .

[0145] Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Each optical property was measured using an ultraviolet-visible-near-infrared spectrophotometer (UH-4150, manufactured by Hitachi High-Technologies Corporation). Unless otherwise specified, the spectral properties are values ​​measured at an incident angle of 0 degrees (perpendicular to the main surface).

[0146] The structures of compounds 1 to 19, which are the dyes used in each example, are as follows, and they were prepared by the methods described below. Compounds 1 to 4 are UV dyes (α), compounds 5 to 18 are UV dyes (β), and compound 19 is an IR dye.

[0147]

[0148]

[0149]

[0150] Compounds 1 to 5 were each synthesized by the methods shown below. Compound 6 was synthesized with reference to Japanese Patent No. 6020746. Compound 7 was synthesized using B2728 manufactured by Tokyo Chemical Industry Co., Ltd. Compound 8 was synthesized using Tinuvin PS manufactured by BASF Japan. Compound 9 was synthesized using Tinuvin 928 manufactured by BASF Japan. Compound 10 was synthesized using Tinuvin 460 manufactured by BASF Japan. Compounds 11 to 14 were synthesized with reference to Japanese Patent No. 6020746. Compound 15 was synthesized using B3382 manufactured by Tokyo Chemical Industry Co., Ltd. Compound 16 was synthesized using D0765 manufactured by Tokyo Chemical Industry Co., Ltd. Compound 17 was synthesized using D5730 manufactured by Tokyo Chemical Industry Co., Ltd. Compound 18 was synthesized with reference to Japanese Patent Publication No. 2011-184414. Compound 19 was synthesized with reference to Japanese Patent No. 6197940.

[0151] (Synthesis of Compound 1) (1) Synthesis of Intermediate 1 2-(methylthio)benzothiazole (25 g) and methyl p-toluenesulfonate (103 g) were placed in a 1 L recovery flask and reacted at 130°C for 5 hours. After completion of the reaction, the mixture was returned to room temperature and filtered to obtain Intermediate 1 (50.5 g) shown in the following scheme. (2) Synthesis of Compound 1 Next, Intermediate 1 (5.0 g), 1,3-dimethylbarbituric acid (2.1 g), triethylamine (2.8 g), and ethanol (130 mL) obtained above were placed in a 1 L recovery flask and reacted at room temperature for 3 hours. After completion of the reaction, the solvent was removed, and the precipitated solid was filtered and washed to obtain Compound 1 (1.5 g).

[0152]

[0153] (Synthesis of Compound 2) (1) Synthesis of Intermediate 2 1,1'-carbonyldiimidazole (15 g), isobutylamine (15 g), and N,N-dimethylformamide (DMF, 30 mL) were placed in a 1 L recovery flask and reacted at 75°C for 3 hours. After the reaction was completed, the mixture was returned to room temperature, acidified with 1 M aqueous hydrochloric acid, extracted, and the solvent was removed to obtain Intermediate 2 (17 g) shown in the following scheme. (2) Synthesis of Intermediate 3 Next, Intermediate 2 (17 g), malonic acid (10 g), acetic anhydride (33 g), and acetic acid (100 mL) obtained above were placed in a 1 L recovery flask and reacted at 90°C for 3 hours. After the reaction was completed, the mixture was returned to room temperature, water was added, extracted, and then purified by column chromatography to obtain Intermediate 3 (21 g) shown in the following scheme. (3) Synthesis of Compound 2 Compound 2 (2.7 g) was obtained by reacting intermediate 1 with intermediate 3 in the same manner as in (2) Synthesis of Compound 1 above, except that intermediate 3 obtained above was used instead of 1,3-dimethylbarbituric acid in (2) Synthesis of Compound 1 above (Synthesis of Compound 1).

[0154]

[0155] (Synthesis of Compound 3) (1) Synthesis of Intermediate 4 2-amino-4-tert-butylphenol (20 g), tetramethylthiuram disulfide (17.5 g), and water (240 mL) were placed in a 1 L recovery flask and reacted at 80°C for 4 hours. After the reaction was completed, the mixture was returned to room temperature, and potassium carbonate (33 g) and iodomethane (19 g) were added, followed by a reaction at 80°C for 3 hours. After the reaction was completed, the mixture was returned to room temperature, extracted, and then purified with a column to obtain Intermediate 4 (24 g) shown in the following scheme. (2) Synthesis of Intermediate 5 Next, Intermediate 5 (7.4 g) shown in the following scheme was obtained in the same manner as in (1) Synthesis of Intermediate 1 in (Synthesis of Compound 1), except that Intermediate 4 (5.0 g) was used instead of 2-(methylthio)benzothiazole. (3) Synthesis of Compound 3 Compound 3 (1.4 g) was obtained in the same manner as in (2) Synthesis of Compound 1 above (Synthesis of Compound 1), except that Intermediate 5 was used instead of Intermediate 1 and 1,3-diethyl-2-thiobarbituric acid was used instead of 1,3-dimethylbarbituric acid.

[0156]

[0157] (Synthesis of Compound 4) Compound 4 (2.4 g) was obtained in the same manner as in (2) Synthesis of Compound 1 above (Synthesis of Compound 1), except that dimedone was used instead of 1,3-dimethylbarbituric acid.

[0158]

[0159] (Synthesis of Compound 5) (1) Synthesis of Intermediate 6 Intermediate 6 shown in the following scheme was obtained (52 g) in the same manner as in the synthesis of Intermediate 1 above in (1) (Synthesis of Compound 1), except that 2-(methylthio)benzoxazole was used instead of 2-(methylthio)benzothiazole. (2) Synthesis of Compound 5 Compound 5 was obtained (1.5 g) in the same manner as in the synthesis of Compound 1 above in (2) (Synthesis of Compound 1), except that intermediate 6 was used instead of Intermediate 1 and 3-ethylrhodanine was used instead of 1,3-dimethylbarbituric acid.

[0160]

[0161] (Examples 1-1 to 1-18) Each dye consisting of Compounds 1 to 18 listed in Table 3 was dissolved in dichloromethane, and transmission spectroscopy was measured in the wavelength range of 300 to 900 nm. The concentrations of Compounds 1 to 18 were adjusted in dichloromethane so that the transmittance at the maximum absorption wavelength was 10%.

[0162] The obtained transmission spectral curve is calculated as follows, if necessary: ​​{absorbance = -log １０ (transmittance / 100)}, and the maximum absorption wavelength, molar absorption coefficient (×10 ４ The absorbance at half maximum (nm) at the maximum absorption wavelength, the average transmittance at wavelengths of 350 to 370 nm, and the minimum transmittance at wavelengths of 400 to 650 nm were calculated. These are listed in Table 3 as "λmax (nm)" and "molar extinction coefficient (×10 ４The values ​​were summarized in the following categories: "transmittance (350 to 370 nm) (%)", "half width (nm)", "average transmittance (350 to 370 nm) (%)", and "minimum transmittance (400 to 650 nm) (%)". Examples 1-1 to 1-4 are working examples, and Examples 1-5 to 1-18 are comparative examples.

[0163]

[0164] From the above results, Examples 1-1 to 1-4, which are UV dyes consisting of Compounds 1 to 4, are UV dyes (α) that satisfy all of the above properties (i-1) to (i-4). These UV dyes (α) can block ultraviolet light with a wavelength of 350 to 370 nm, which has traditionally been difficult to prevent from causing light leakage, and further improve the blocking properties, i.e., the light absorption strength. Furthermore, they can selectively block ultraviolet light of the desired wavelength and prevent light leakage while maintaining the transmittance in the visible light range, where high transmittance is required, without impairing it.

[0165] (Examples 2-1 to 2-13) A polyimide resin (C-3G30G manufactured by Mitsubishi Gas Chemical Company) serving as a transparent resin was dissolved in an organic solvent of cyclohexanone:γ-butyrolactone = 1:1 (mass ratio) to prepare a polyimide resin solution. Each of the compounds listed in Table 4 serving as UV dyes and an IR dye consisting of Compound 19 were added to the polyimide resin solution in the proportions listed in Table 4 relative to 100 parts by mass of the polyimide resin, and the mixture was stirred at 50°C for 2 hours to prepare a dye-containing resin solution. This dye-containing resin solution was applied by spin coating to a glass substrate (alkali glass, D263 manufactured by SCHOTT) serving as a support, followed by heating to obtain a resin layer having a film thickness listed in Table 4.

[0166] The glass substrate on which the resin layer was formed was used to obtain a spectral transmittance curve and a spectral reflectance curve for wavelengths of 350 nm to 1200 nm using an ultraviolet-visible-near-infrared spectrophotometer (UH4150, manufactured by Hitachi High-Tech Science). The average internal transmittance (D) (%) for wavelengths of 350 to 370 nm, the average internal transmittance (E) (%) for wavelengths of 400 to 440 nm, the ratio of the two average internal transmittances {(E) / (D)}, the average internal transmittance (F) (%) for wavelengths of 440 to 500 nm, and the internal transmittance T at a wavelength of 700 nm were then measured. ７００The average internal transmittance (D) (350-370 nm) (%), the average internal transmittance (E) (400-440 nm) (%), the average internal transmittance (F) (440-500 nm) (%), the wavelength IR50 (nm) at which the internal transmittance becomes 50% in the spectral internal transmittance curve for wavelengths of 600-700 nm, and the wavelength IR50 (nm) at which the internal transmittance becomes 50% were determined. These are shown in Table 4 under the headings "Average internal transmittance (D) (350-370 nm) (%)," "Average internal transmittance (E) (400-440 nm) (%)," "(E) / (D)," "Average internal transmittance (F) (440-500 nm) (%)," and "Internal transmittance T ７００ The results are summarized in "IR50 (nm)" and "IR (%)", respectively. Examples 2-1 to 2-3 and 2-13 are working examples, and Examples 2-4 to 2-12 are comparative examples.

[0167]

[0168] From the above results, the resin layers of Examples 2-1 to 2-3 and 2-13 containing the UV dye (α) satisfy all of the above properties (iv-1) to (iv-6), have high light-blocking properties in the near-ultraviolet light region, and do not lose their ultraviolet light-blocking properties even at high incident angles. Furthermore, from the results of Example 2-13, it was found that the above effects can be obtained even when two types of UV dyes corresponding to the UV dye (α) and the UV dye (β) are used in combination as the UV dye.

[0169] (Examples 3-1 to 3-8) A glass substrate having a resin layer of Example 2-1, Examples 2-3 to 2-5, Examples 2-9 to 2-11, or Example 2-13 shown in Table 5 formed thereon was used, and TiO ２ layer and SiO ２ An antireflection layer was formed from a dielectric multilayer film in which layers were alternately laminated, to obtain a substrate.

[0170] The above substrate was subjected to a UV-visible-near-infrared spectrophotometer (UH4150, manufactured by Hitachi High-Tech Science) to obtain a spectral transmittance curve for wavelengths of 350 nm to 1200 nm. The spectral transmittance curves for Examples 3-1 and 3-8 are shown in Figures 2 and 3, respectively. Based on the obtained spectral transmittance curves, the average transmittance (A) (%) for wavelengths of 350 to 370 nm, the average transmittance (B) (%) for wavelengths of 400 to 440 nm, the ratio of the above two average transmittances {(B) / (A)}, the average transmittance (C) (%) for wavelengths of 440 to 500 nm, and the transmittance T at a wavelength of 700 nm were calculated. ７００The average transmittance (A) (350-370 nm) (%), the average transmittance (B) (400-440 nm) (%), the average transmittance (B) (440-500 nm) (%), the wavelength IR50 (nm) at which the transmittance becomes 50% in the spectral transmittance curve of wavelengths from 600 to 700 nm, and the wavelength IR50 (nm) at which the transmittance becomes 50% were determined. These are shown in Table 5 as "Average transmittance (A) (350-370 nm) (%)," "Average transmittance (B) (400-440 nm) (%)," "(B) / (A)," "Average transmittance (C) (440-500 nm) (%)," and "Transmittance T ７００ The results are summarized in "IR50 (nm)" and "IR (%)", respectively. Examples 3-1, 3-2 and 3-8 are working examples, and Examples 3-3 to 3-7 are comparative examples.

[0171] Furthermore, using the ultraviolet-visible-near-infrared spectrophotometer, a spectral reflectance curve was obtained for the antireflection layer side of the dielectric multilayer film of the substrate of Example 3-1, with an incident angle of 5 degrees. The results are shown in Figure 4. Since there was no wavelength in the wavelength range of 750 to 1200 nm at which the reflectance was 90% or higher, it was confirmed that the dielectric multilayer film was an antireflection layer, not a reflective layer. Furthermore, since the substrates of Examples 3-2 to 3-8 also had the same dielectric multilayer film as the substrate of Example 3-1, the dielectric multilayer films of the substrates of Examples 3-1 to 3-8 were all antireflection layers.

[0172]

[0173] From the above results, the substrates of Examples 3-1, 3-2, and 3-8 containing UV dye (α) satisfy all of the above properties (ii-1) to (ii-6), and are superior in blocking near-infrared light and ultraviolet light while maintaining high transmittance of visible light. Specifically, it can be seen that Examples 3-1 and 3-2 are particularly excellent in blocking light in the UV band, and the value represented by {(B) / (A)} is large. Furthermore, from the results of Example 3-8, it was found that the above effect can be obtained even when two dyes corresponding to UV dye (α) and UV dye (β) are used in combination as UV dyes.

[0174] (Examples 4-1 to 4-4) For the substrates of Examples 3-1, 3-2, 3-6, and 3-8 listed in Table 6, TiO was applied to the surface of the glass substrate opposite to the antireflection layer. ２ layer and SiO ２ A reflective layer was formed from a dielectric multilayer film in which layers were alternately stacked, thereby obtaining an optical filter.

[0175] The optical filter was used to obtain a spectral transmittance curve for wavelengths of 350 nm to 1200 nm using an ultraviolet-visible-near-infrared spectrophotometer (UH4150, manufactured by Hitachi High-Tech Science). The spectral transmittance curves for Examples 4-1 and 4-4 at angles of incidence of 0 degrees, 30 degrees, and 50 degrees are shown in Figures 5 and 6, respectively. Based on the obtained spectral transmittance curves, the average transmittance (%) and maximum transmittance (%) for wavelengths of 350 to 370 nm when the angles of incidence were 0 degrees, 30 degrees, and 50 degrees, the average transmittance (%) for wavelengths of 440 to 500 nm when the angle of incidence was 0 degrees, and the transmittance T at a wavelength of 700 nm when the angle of incidence was 0 degrees were calculated. ７００ The average transmittance (350-370 nm) (%) at an incident angle of 0 degrees, 30 degrees, and 50 degrees, and the fluctuation (nm) at the wavelength IR50 at which the transmittance is 50% in the spectral transmittance curve for wavelengths of 600 to 700 nm, were calculated for angles of incidence of 0 degrees and 30 degrees. These are shown in Table 6 as "Average transmittance (350-370 nm) (%) at an incident angle of 0 degrees, 30 degrees, and 50 degrees," "Maximum transmittance (350-370 nm) (%) at an incident angle of 0 degrees, 30 degrees, and 50 degrees," "Average transmittance (440-500 nm) (%)," and "Transmittance T ７００ (%)" and "ΔIR50 (nm)." Examples 4-1, 4-2, and 4-4 are working examples, and Example 4-3 is a comparative example.

[0176] Furthermore, using the ultraviolet-visible-near-infrared spectrophotometer, a spectral reflectance curve was obtained for the reflective layer side of the dielectric multilayer film in the optical filter of Example 4-1, with an incident angle of 5 degrees. The results are shown in Figure 7. Since the wavelength band in which the reflectance is 90% or higher continues for 100 nm or more in the wavelength range of 750 to 1200 nm, it was confirmed that the dielectric multilayer film is a reflective layer. Furthermore, since the optical filters of Examples 4-2 to 4-4 also have the same dielectric multilayer film as the optical filter of Example 4-1, the dielectric multilayer film formed as the outermost layer on the side opposite the antireflection layer in the optical filters of Examples 4-1 to 4-4 is all a reflective layer.

[0177]

[0178] From the above results, the optical filters of Examples 4-1, 4-2, and 4-4 containing the UV dye (α) satisfy all of the above properties (iii-1) to (iii-5), and while maintaining high transmittance of visible light, are particularly excellent in blocking wavelengths of 350 to 370 nm. Furthermore, from the results of Example 4-4, it was found that the above effect can be obtained even when two types of dyes corresponding to the UV dye (α) and the UV dye (β) are used in combination as the UV dye.

[0179] (Examples 5-1 to 5-4) The substrates of Examples 3-1 to 3-3, 3-5, and 3-6 shown in Table 7 were irradiated with light from the antireflection layer side, and a light resistance test was carried out using a Super Xenon Weather Meter (manufactured by Suga Test Instruments Co., Ltd.). The irradiated light was in the wavelength range of 300 to 2450 nm, and the cumulative light intensity was 80,000 J / mm ２ The dye remaining rate was calculated from the absorbance at the maximum absorption wavelength of the dye before and after the light fastness test according to the following formula. The results are shown in Table 7. Dye remaining rate (%) = (absorbance at the maximum absorption wavelength after the test / absorbance at the maximum absorption wavelength before the test) x 100

[0180]

[0181] From the above results, it was found that the substrates of Examples 5-1 and 5-2 containing the UV dye (α) were resistant to light and had a very high dye retention rate.

[0182] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application (Patent Application No. 2022-079825) filed on May 13, 2022, the contents of which are incorporated herein by reference.

[0183] REFERENCE SIGNS LIST 1 Optical filter 10 Substrate 11 Support 12 Resin layer 13 Anti-reflection layer 20 Reflection layer

Claims

1. An optical filter comprising a substrate and a dielectric multilayer film laminated on at least one main surface side of the substrate, The substrate has a resin layer, The resin layer comprises a transparent resin, a UV dye that satisfies all of the following properties (i-1) to (i-4), and an IR dye that has a maximum absorption wavelength in the wavelength range of 650 to 800 nm. Characteristics (i-1) Maximum absorption wavelength in dichloromethane at wavelengths of 340 to 375 nm Characteristics (i-2) Molar absorption coefficient in dichloromethane is 3.0 × 10 ４ L / mol・cm or more Characteristic (i-3) The half-value width at the maximum absorption wavelength of the characteristic (i-1) is 40 nm or less. Characteristic (i-4) In a spectral transmittance curve measured by dissolving the sample in dichloromethane in a concentration adjusted so that the transmittance at the maximum absorption wavelength of characteristic (i-1) is 10%, the average transmittance at a wavelength of 350 to 370 nm is 20% or less.

2. 2. The optical filter of claim 1, wherein the UV dye further satisfies the following characteristic (i-5): Characteristic (i-5): In a spectral transmittance curve measured by dissolving the sample in dichloromethane in a concentration adjusted so that the transmittance of the maximum absorption wavelength of characteristic (i-1) is 10%, the minimum transmittance of the sample in the wavelength range of 400 to 650 nm is 85% or more.

3. 2. The optical filter of claim 1, wherein the UV dye further satisfies the following characteristic (i-6): Characteristic (i-6): In a spectral transmittance curve measured by dissolving the sample in dichloromethane in a concentration adjusted so that the transmittance at the maximum absorption wavelength of characteristic (i-1) is 10%, the average transmittance at a wavelength of 350 to 370 nm is 15% or less.

4. 2. The optical filter of claim 1, wherein the UV dye is a compound represented by the following formula (I): 【Chemistry 1】 (In formula (I), X is an oxygen atom, a sulfur atom, or an N-R １４ , or C-R １５ R １６ (R １４ ~R １６ each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms which may have a substituent, R １ is an alkyl group having 1 to 6 carbon atoms which may have a substituent, R ２ ~R ５ are each independently a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group having 1 to 10 carbon atoms which may have a substituent, a nitro group, an amino group, or an amido group, and A represents any of the divalent groups represented by the following formulas (A1) to (A4): 【Chemistry 2】 In formulas (A1) to (A4), Y is an oxygen atom or a sulfur atom, and R ６ ~R １３ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, or a phenyl group.

5. 5. The optical filter according to claim 4, wherein in the compound represented by formula (I), X is an oxygen atom or a sulfur atom.

6. 5. The optical filter according to claim 4, wherein in the compound represented by formula (I), A is a divalent group represented by formula (A1) or (A3).

7. 5. The optical filter according to claim 4, wherein in the compound represented by formula (I), A is a divalent group represented by formula (A1), and at least one of X and Y is an oxygen atom.

8. 2. The optical filter according to claim 1, wherein the IR dye is at least one dye selected from the group consisting of squarylium dyes, phthalocyanine dyes, and cyanine dyes.

9. 2. The optical filter according to claim 1, wherein the substrate satisfies all of the following characteristics (ii-1) to (ii-6): Characteristic (ii-1) Average transmittance (A) at wavelengths of 350 to 370 nm is 15% or less Characteristic (ii-2) Average transmittance (B) at wavelengths of 400 to 440 nm is 48% or more Property (ii-3): the average transmittances (A) and (B) satisfy the relationship {(B) / (A)}≧6.0 Characteristic (ii-4) Average transmittance (C) of 88% or more at wavelengths of 440 to 500 nm Characteristic (ii-5) Transmittance T at a wavelength of 700 nm ７００ Less than 5% Characteristic (ii-6) In the spectral transmittance curve for wavelengths of 600 to 700 nm, the wavelength IR50 at which the transmittance is 50% is in the range of 610 to 670 nm.

10. The optical filter according to claim 1 , wherein the optical filter satisfies all of the following characteristics (iii-1) to (iii-5): Characteristic (iii-1) Transmittance T at a wavelength of 700 nm and an incident angle of 0 degrees ７００ Less than 1% Characteristic (iii-2) In the spectral transmittance curve for wavelengths of 600 to 700 nm, the variation of the wavelength IR50 at which the transmittance is 50% between an incident angle of 0 degrees and an incident angle of 30 degrees is 4 nm or less. Characteristic (iii-3) The average transmittance at wavelengths of 350 to 370 nm is 0.5% or less at an incident angle of 0 degrees, 0.5% or less at an incident angle of 30 degrees, and 0.5% or less at an incident angle of 50 degrees. Characteristic (iii-4) The maximum transmittance at wavelengths of 350 to 370 nm is 5% or less at an incident angle of 0 degrees, 5% or less at an incident angle of 30 degrees, and 5% or less at an incident angle of 50 degrees. Property (iii-5) The average transmittance for wavelengths of 440 to 500 nm is 88% or more at an incident angle of 0 degrees

11. An imaging device comprising the optical filter according to any one of claims 1 to 10.

12. A UV dye comprising a compound represented by the following formula (I)'. 【Chemistry 3】 In formula (I), X is an oxygen atom or a sulfur atom, and R １ is a methyl group or an alkyl group having 3 to 6 carbon atoms, R ２ ~R ５ each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, a nitro group, an amino group, or an amide group, and A represents any of the divalent groups represented by the following formulas (A1) to (A4): 【Chemistry 4】 In formulae (A1) to (A4), Y is an oxygen atom or a sulfur atom, R 6 is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms which may have a substituent, an isobutyl group, an alkyl group having 5 to 10 carbon atoms which may have a substituent, or a phenyl group, and R 7 to R １３ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, or a phenyl group.

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