Optical Filters

Abstract

To provide an optical filter having high permeability of visible light and high shieldability of near infrared light and ultraviolet light, specifically with high permeability of blue light, while suppressing a deterioration in shieldability of ultraviolet light at a high incident angle.SOLUTION: An optical filter includes: a substrate satisfying prescribed spectral characteristics; and a dielectric multilayer laminated at least on one principal side of the substrate. The substrate includes a resin film including: a pigment (U) having a maximum absorption wavelength at 360-395 nm in dichloromethane; a pigment (A) having a maximum absorption wavelength at 600-800 nm in dichloromethane; and a resin.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an optical filter that transmits light in the visible wavelength region and blocks light in the ultraviolet and near-infrared wavelength regions. [Background technology]

[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" or "UV") and light in the near-infrared wavelength range (hereinafter also referred to as "near-infrared light" or "NIR").

[0003] Such optical filters include various types, such as reflective filters in which dielectric thin films with different refractive indices are alternately stacked on one or both sides of a transparent substrate (dielectric multilayer film), and the filters utilize optical interference to reflect light to be blocked. Optical filters with dielectric multilayer films have problems, such as changes in the spectral transmittance curve depending on the angle of incidence, light leakage due to high transmittance of ultraviolet light that should have high reflectance at high angles of incidence, and noise due to ultraviolet light reflected by the dielectric multilayer film, because the optical thickness of the dielectric multilayer film changes depending on the angle of incidence. The use of such filters can potentially affect the spectral sensitivity of solid-state imaging devices depending on the angle of incidence. Therefore, there has been a demand for an optical filter that blocks ultraviolet light independently of the angle of incidence without substantially affecting the transmittance of visible light.

[0004] In contrast, Patent Documents 1 to 4 describe optical filters that have little dependency on the angle of incidence of light with wavelengths of 370 to 425 nm, and that have both UV and NIR blocking capabilities by combining an absorption layer containing a UV absorbing dye and an NIR absorbing dye in a transparent resin with a dielectric multilayer film. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-16649 [Patent Document 2] Japanese Patent No. 6504176 [Patent Document 3] Japanese Patent No. 6020740 [Patent Document 4] Japanese Patent No. 6256335 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the optical filters described in Patent Documents 1 to 4 have room for improvement in terms of transmittance of visible light, particularly blue light, and blocking of ultraviolet light at high angles of incidence. Therefore, an object of the present invention is to provide an optical filter that has high transmittance for visible light, high blocking properties for near-infrared light and ultraviolet light, and in particular, high transmittance for blue light, and that suppresses a decrease in blocking properties for ultraviolet light at high angles of incidence. [Means for solving the problem]

[0007] The present invention provides an optical filter having the following configuration. [1] An optical filter comprising a substrate and a dielectric multilayer film laminated on at least one main surface of the substrate, the substrate has a resin film containing a dye (U) having a maximum absorption wavelength in dichloromethane of 360 to 395 nm, a dye (A) having a maximum absorption wavelength in dichloromethane of 600 to 800 nm, and a resin; The optical filter satisfies all of the following spectral characteristics (i-1) to (i-4): (i-1) Average transmittance T in the spectral transmittance curve of wavelengths from 440 to 480 nm 440-480 Over 86% (i-2) The wavelength at which the transmittance is 10% at a wavelength of 350 to 450 nm and an incident angle of 0 degrees is called UV10. (0deg) The wavelength when the transmittance is 20% is called UV20 (0deg) The wavelength at which the transmittance is 50% is called UV50 (0deg) year, The wavelength at which the transmittance is 10% at a wavelength of 350 to 450 nm and an incident angle of 50 degrees is defined as UV10. (50deg) The wavelength when the transmittance is 20% is called UV20 (50deg) The wavelength at which the transmittance is 50% is called UV50 (50deg) When UV10 (0deg) and UV10 (50deg) The absolute value of the difference is 3 nm or less. UV20 (0deg) and UV20 (50deg) The absolute value of the difference is 4 nm or less. UV50 (0deg) and UV50 (50deg) The absolute difference is 4nm or less (i-3) Average transmittance T in the spectral transmittance curve of wavelengths from 400 to 440 nm 400-440 More than 40% (i-4) Average transmittance T in the spectral transmittance curve at wavelengths of 370 to 400 nm and an incident angle of 0 degrees 370-400(0deg) is less than 1% [Effects of the Invention]

[0008] According to the present invention, an optical filter can be provided that has high transmittance for visible light, high blocking properties for near-infrared light and ultraviolet light, and in particular, high transmittance for blue light, and that suppresses a decrease in blocking properties for ultraviolet light at high angles of incidence. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view schematically illustrating an example of an optical filter according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view schematically showing another example of the optical filter according to the embodiment. [Figure 3] FIG. 3 is a cross-sectional view schematically showing another example of the optical filter according to the embodiment. [Figure 4] FIG. 4 is a cross-sectional view schematically showing another example of the optical filter according to the embodiment. [Figure 5] FIG. 5 is a diagram showing the spectral transmittance curve of the optical filter of Example 2-14. [Figure 6]FIG. 6 is a diagram showing the spectral transmittance curve of the optical filter of Example 2-15. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described. In this specification, the near-infrared absorbing dye may be abbreviated as "NIR dye" and the ultraviolet absorbing dye may be abbreviated as "UV dye". 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. Furthermore, a group represented by formula (I) is also referred to as group (I), and the same applies to groups represented by other formulas.

[0011] 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). In this specification, the transmittance of a substrate and the transmittance of a resin film, including a case where a dye is contained in the resin, are all referred to as "internal transmittance" even when they are referred to as "transmittance." On the other hand, the transmittance measured by dissolving a dye in a solvent such as dichloromethane and the transmittance of an optical filter having a dielectric multilayer film are actually measured transmittances.

[0012] In this specification, for example, a transmittance of 90% or more in a specific wavelength range means that the transmittance is not less than 90% across the entire wavelength range, i.e., the minimum transmittance is 90% or more across the wavelength range. Similarly, for example, a transmittance of 1% or less in a specific wavelength range means that the transmittance is not more than 1% across the entire wavelength range, i.e., the maximum transmittance is 1% or less across the wavelength range. The same applies to internal transmittance. The average transmittance and average internal transmittance in a specific wavelength range are the arithmetic mean of the transmittance and internal transmittance per 1 nm in the wavelength range. In this specification, the use of "to" to indicate a range of values ​​includes the upper and lower limits.

[0013] <Optical filters> An optical filter according to one embodiment of the present invention (hereinafter also referred to as "the present filter") comprises a substrate and a dielectric multilayer film laminated as an outermost layer on at least one main surface of the substrate, and satisfies specific spectral characteristics described below. Here, the substrate has a resin film containing a dye (U) having a maximum absorption wavelength in dichloromethane at 360 to 395 nm, a dye (A) having a maximum absorption wavelength in dichloromethane at 600 to 800 nm, and a resin.

[0014] An example of the configuration of the present filter will be described with reference to the drawings. Figures 1 to 4 are cross-sectional views that schematically show an example of an optical filter according to an embodiment. 1 is an example in which a dielectric multilayer film 30 is provided on one main surface side of a substrate 10. Note that "having a specific layer on the main surface side of the substrate" does not only mean that the layer is provided in contact with the main surface of the substrate, but also includes a case in which another functional layer is provided between the substrate and the layer.

[0015] The optical filter 1B shown in FIG. 2 is an example in which the substrate 10 has a dielectric multilayer film 30 on both main surfaces thereof.

[0016] 3 is an example in which a substrate 10 has a support 11 and a resin film 12 laminated on one main surface of the support 11. The optical filter 1C further has a dielectric multilayer film 30 on the resin film 12 and on the main surface of the support 11 on which the resin film 12 is not laminated.

[0017] 4 is an example in which a substrate 10 has a support 11 and resin films 12 laminated on both main surfaces of the support 11. The optical filter 1D further has a dielectric multilayer film 30 on each of the resin films 12.

[0018] The substrate in the optical filter of the present invention contains a dye (U) having a maximum absorption wavelength in dichloromethane at 360 to 395 nm, a dye (A) having a maximum absorption wavelength in dichloromethane at 600 to 800 nm, and a resin. The dye (U) is a UV dye, and the dye (A) is an NIR dye. By containing dyes that absorb ultraviolet and near-infrared light in the substrate, the absorption characteristics of the substrate can suppress deterioration of the spectral characteristics of the dielectric multilayer film at high incident angles, such as light leakage and noise in the ultraviolet and near-infrared regions. Each dye and resin will be described later.

[0019] The optical filter of the present invention satisfies all of the following spectral characteristics (i-1) to (i-5). (i-1) Average transmittance T in the spectral transmittance curve of wavelengths from 440 to 480 nm 440-480 Over 86% (i-2) The wavelength at which the transmittance is 10% at a wavelength of 350 to 450 nm and an incident angle of 0 degrees is called UV10. (0deg) The wavelength when the transmittance is 20% is called UV20 (0deg) The wavelength at which the transmittance is 50% is called UV50 (0deg year, The wavelength at which the transmittance is 10% at a wavelength of 350 to 450 nm and an incident angle of 50 degrees is defined as UV10. (50deg) The wavelength when the transmittance is 20% is called UV20 (50deg) The wavelength at which the transmittance is 50% is called UV50 (50deg) When UV10 (0deg) and UV10 (50deg) The absolute value of the difference is 3 nm or less. UV20 (0deg) and UV20 (50deg) The absolute value of the difference is 4 nm or less. UV50 (0deg) and UV50 (50deg) The absolute difference is 4nm or less (i-3) Average transmittance T in the spectral transmittance curve of wavelengths from 400 to 440 nm 400-440 More than 40% (i-4) Average transmittance T in the spectral transmittance curve at wavelengths of 370 to 400 nm and an incident angle of 0 degrees 370-400(0deg) is less than 1% (i-5) Average transmittance T in the spectral transmittance curve at wavelengths of 370 to 400 nm and an incident angle of 50 degrees 370-400(50deg) is 0.5% or less

[0020] This filter, which satisfies all of the spectral characteristics (i-1) to (i-5), is an optical filter that maintains good transmittance of visible light, particularly blue light, while suppressing a decrease in ultraviolet light blocking ability, especially at high incident angles.

[0021] By satisfying the spectral characteristic (i-1), it means that the transmittance in the visible light range is excellent. 440-480 is preferably 87% or more, more preferably 89% or more.

[0022] By satisfying the spectral characteristic (i-2), it means that there is little shift even at high angles of incidence and excellent color reproducibility in the UV absorption start band of wavelengths 350 to 450 nm. (0deg) and UV10 (50deg) The absolute value of the difference between the UV20 and UV30 is preferably 2.5 nm or less. (0deg) and UV20 (50deg) The absolute value of the difference between the UV50 and UV60 is preferably 3 nm or less. (0deg) and UV50 (50deg) The absolute value of the difference between is preferably 3 nm or less.

[0023] By satisfying the spectral characteristic (i-3), it means that the transmittance of blue light is excellent in the wavelength range of 400 to 440 nm, before the UV absorption onset band. 400-440 is preferably 45% or more, more preferably 50% or more.

[0024] By satisfying the spectral characteristic (i-4), it means that the light-shielding property in the UV absorption band of wavelengths from 370 to 400 nm is high. 370-400(0deg) is preferably 0.5% or less.

[0025] By satisfying the spectral characteristic (i-5), it means that in the UV absorption band of wavelengths 370 to 400 nm, light leakage is less likely to occur even at high incident angles, and the light shielding property is high. The T of the spectral characteristic (i-5) 370-400(50deg) is preferably 0.1% or less.

[0026] The optical filter of the present invention preferably further satisfies the following spectral characteristic (i-6). (i-6) At wavelengths 350 to 450 nm and an incident angle of 0 degrees, when the transmittance is 10%, the wavelength is UV10 (0deg) , and when the transmittance is 70%, the wavelength is UV70 (0deg) When defined as such, the absolute value of the difference between UV10 (0deg) and UV70 (0deg) is 16 nm or less

[0027] By satisfying the spectral characteristic (i-6), it means that in the UV absorption start band of wavelengths 350 to 450 nm, the slope of the spectral transmittance curve is steep. The absolute value in the spectral characteristic (i-6) is more preferably 14 nm or less, and particularly preferably 13 nm or less.

[0028] Hereinafter, the substrate and the dielectric multilayer film will be described. This filter is designed, for example, to give the substrate an absorption ability for ultraviolet light and near-infrared light, and to satisfy the above respective spectral characteristics (i-1) to (i-5) by the absorption characteristics of the substrate and the reflection characteristics of the dielectric multilayer film.

[0029] <Substrate> In the optical filter of the present invention, the substrate has a resin film containing a dye (U), a dye (A) described later, and a resin.

[0030] <UV Dye> The dye (U) is a UV dye having a maximum absorption wavelength at 360 to 395 nm in dichloromethane. By containing such a dye, ultraviolet light can be effectively cut.

[0031] The dye (U) preferably has specific spectral characteristics in the resin. Specifically, the dye (U) preferably has a spectral transmittance curve of a coating film formed by dissolving the dye (U) in a resin and coating the coating film on an alkali glass plate, and the spectral transmittance curve of the coating film preferably satisfies all of the following spectral characteristics (ii-1) to (ii-6). The resin is preferably the same as the resin contained in the substrate.

[0032] (ii-1) Average transmittance T at wavelengths of 400 to 440 nm 400-440 More than 40% (ii-2) Average transmittance T at wavelengths of 370 to 400 nm 370-400 is 5% or less (ii-3) Transmittance T at a wavelength of 400 nm 400 is 7% or less (ii-4) Transmittance T at a wavelength of 390 nm 390 is 5% or less (ii-5) Transmittance T at a wavelength of 380 nm 380 is 5% or less (ii-6) Transmittance T at a wavelength of 370 nm 370 is 5% or less

[0033] By satisfying the optical property (ii-1), it means that the film has excellent transmittance for blue light in the wavelength range of 400 to 440 nm, before the UV absorption onset band. 400-440 is more preferably 45% or more, and particularly preferably 50% or more.

[0034] Satisfying the optical property (ii-2) means that the light-shielding property in the UV absorption band of wavelengths from 370 to 400 nm is high. 370-400 is more preferably 3% or less, and particularly preferably 2% or less.

[0035] By satisfying the optical property (ii-3), the transmittance at 400 nm, which is the UV absorption start wavelength, is low, which means that the light blocking ability on the shorter wavelength side is high. 400 is more preferably 5% or less, and particularly preferably 2% or less.

[0036] By satisfying the optical properties (ii-4) to (ii-6), it is possible to ensure light blocking properties through absorption in the wavelength range of 370 to 390 nm, where a dielectric multilayer film is unable to completely block light at high angles of incidence and light leakage is likely to occur. Optical property (ii-4) T 390 is more preferably 3% or less, and particularly preferably 1% or less. Optical properties (ii-5) T 380 is more preferably 3% or less, and particularly preferably 1% or less. Optical properties (ii-6) T 370 is more preferably 3% or less, and particularly preferably 1% or less.

[0037] It is preferable that the dye (U) further satisfies the following spectral characteristic (ii-7) in the spectral transmittance curve of the coating film. (ii-7) Average internal transmittance T at wavelengths of 440 to 480 nm 440-480 Over 79% By satisfying the optical property (ii-7), it means that the absorption of the dye itself does not cause a loss of transmittance in the visible light range. 440-480 is more preferably 80% or more, and particularly preferably 81% or more.

[0038] Moreover, it is preferable that the dye (U) satisfies the following spectral characteristic (iii-1). (iii-1) In the spectral transmittance curve measured by dissolving the dye (U) in dichloromethane so that the transmittance at the maximum absorption wavelength is 10%, when the wavelength at which the transmittance at wavelengths of 350 to 450 nm is 10% is defined as UV10 and the wavelength at which the transmittance is 70% is defined as UV70, the absolute value of the difference between UV10 and UV70 is 25 nm or less. Satisfying the spectral characteristic (iii-1) means that the slope of the spectral transmittance curve is steep in the UV absorption onset band of 350 to 450 nm, which allows more of the necessary blue light to pass through and efficiently blocks the desired ultraviolet light range. The absolute value of the spectral characteristic (iii-1) is more preferably 22 nm or less.

[0039] The dye (U) may be used alone or in combination with two or more types in the base material, but from the viewpoint of more efficiently blocking ultraviolet light with a small content, it is preferable to use two or more types with different maximum absorption wavelengths in combination. Furthermore, when two or more types are used in combination, each compound does not necessarily have the properties of the dye (U), as long as the mixture has the properties of the dye (U).

[0040] The dye (U) is preferably dye (U1), which has a maximum absorption wavelength in dichloromethane at 370 to 385 nm. Furthermore, when the substrate contains dye (U1), it is preferable that the substrate further contains dye (U2), which has a maximum absorption wavelength in dichloromethane at 385 to 405 nm. The maximum absorption wavelengths of dye (U1) and dye (U2) in the resin are preferably different, and the absolute value of the difference in the maximum absorption wavelengths in the resin is preferably 10 to 15 nm, more preferably 10 to 14 nm. By using UV dyes with different maximum absorption wavelengths in combination, it is possible to more efficiently block ultraviolet light with a small amount.

[0041] Examples of the dye (U) include oxazole dyes, merocyanine dyes, cyanine dyes, naphthalimide dyes, oxadiazole dyes, oxazine dyes, oxazolidine dyes, naphthalic acid dyes, styryl dyes, anthracene dyes, cyclic carbonyl dyes, triazole dyes, etc. Among these, oxazole dyes and merocyanine dyes are preferred, and merocyanine dyes are more preferred.

[0042] Furthermore, from the viewpoint of obtaining an optical filter with excellent light resistance, it is particularly preferable to use two or more merocyanine dyes with different maximum absorption wavelengths in combination. The NIR dye (A) is prone to deterioration when used in combination with a UV dye, but this can be prevented by using two or more merocyanine dyes in combination as UV dyes.

[0043] As the dye (U), a merocyanine dye represented by the following formula (M) is particularly preferred.

[0044] [ka]

[0045] The symbols in formula (M) are as follows:

[0046] R 1 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.

[0047] Unsubstituted R 1 Specifically, preferred are alkyl groups having 1 to 12 carbon atoms in which some of the hydrogen atoms may be substituted with an aliphatic ring, an aromatic ring, or an alkenyl group; cycloalkyl groups having 3 to 8 carbon atoms in which some of the hydrogen atoms may be substituted with an aromatic ring, an alkyl group, or an alkenyl group; and aryl groups having 6 to 12 carbon atoms in which some of the hydrogen atoms may be substituted with an aliphatic ring, an alkyl group, or an alkenyl group.

[0048] R 1 When is an unsubstituted alkyl group, the alkyl group may be linear or branched, and more preferably has 1 to 6 carbon atoms.

[0049] R 1is an alkyl group having 1 to 12 carbon atoms in which some of the hydrogen atoms are substituted with an aliphatic ring, an aromatic ring, or an alkenyl group, an alkyl group having 1 to 4 carbon atoms having a cycloalkyl group having 3 to 6 carbon atoms, or an alkyl group having 1 to 4 carbon atoms substituted with a phenyl group is more preferred, and an alkyl group having 1 or 2 carbon atoms substituted with a phenyl group is particularly preferred. Note that an alkyl group substituted with an alkenyl group means an alkenyl group as a whole that does not have an unsaturated bond between the 1- and 2-positions, such as an allyl group or a 3-butenyl group.

[0050] Preferred R 1 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. Particularly preferred is Q 1 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.

[0051] R 2 ~R 5 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.

[0052] R 2 and R 3 At least one of R is preferably an alkyl group, and more preferably both are alkyl groups. 2 and R 3 When R is not an alkyl group, a hydrogen atom is more preferred. 2 and R 3 In any case, an alkyl group having 1 to 6 carbon atoms is particularly preferred.

[0053] R 4 and R 5 At least one of R is preferably a hydrogen atom, and more preferably both are hydrogen atoms. 4 or R 5 When is not a hydrogen atom, it is preferably an alkyl group having 1 to 6 carbon atoms.

[0054] Y is R 6 and R 7 represents a methylene group or an oxygen atom substituted with R 6 and R 7 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.

[0055] X represents any one of the divalent groups represented by the following formulas (X1) to (X5).

[0056] [ka]

[0057] R 8 and R 9 each independently represents a monovalent hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, and R 10 ~R 19 each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms which may have a substituent. R 8 ~R 19 The substituents of R 1 The same substituents as those in R are mentioned, and the preferred embodiments are also the same. 8 ~R 19 is a hydrocarbon group having no substituents, R 1 The same aspects as above can be mentioned.

[0058] In formula (X1), R 8 and R 9 may be different groups, but are preferably the same group. 8 and R 9 When is an unsubstituted alkyl group, it may be linear or branched, and more preferably has 1 to 6 carbon atoms.

[0059] Preferred R 8 and R 9Each of R 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. 8 and R 9 are all alkyl groups having 1 to 6 carbon atoms, and specific examples 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.

[0060] In formula (X2), R 10 and R 11 are more preferably alkyl groups having 1 to 6 carbon atoms, and it is particularly preferred that they are the same alkyl groups.

[0061] In formula (X3), R 12 and R 15 are preferably both hydrogen atoms or unsubstituted alkyl groups having 1 to 6 carbon atoms. 13 and R 14 are preferably all hydrogen atoms or all alkyl groups having 1 to 6 carbon atoms.

[0062] In formula (X4), two groups R bonded to the same carbon atom 16 and R 17 and R 18 and R 19 are preferably all hydrogen atoms or all alkyl groups having 1 to 6 carbon atoms.

[0063] As the compound represented by formula (M), a compound in which Y is an oxygen atom and X is a group (X1), a group (X2) or a group (X5), and a compound in which Y is an unsubstituted methylene group and X is a group (X1), a group (X2) or a group (X5) are preferred.

[0064] Specific examples of the compound (M) that can be used as the dye (U) include the compounds shown in the table below.

[0065] [Table 1]

[0066] [Table 2]

[0067] Specific examples of the compound (M) that can be used as the dye (U1) include the compounds shown in the table below.

[0068] [Table 3]

[0069] Specific examples of the compound (M) that can be used as the dye (U2) include the compounds shown in the table below.

[0070] [Table 4]

[0071] Among these, compounds (M) are preferably compounds (1-1-2), (M-1-10), (M-1-24), (M-1-28), etc., in terms of solubility in resins and solvents, visible light transmittance, and particularly optical properties (iii-1). When two compounds (M) with different maximum absorption wavelengths are used in combination, the combination of compounds (M-1-28) and (M-1-2), the combination of compounds (M-1-28) and (M-1-10), the combination of compounds (M-1-24) and (M-1-2), and the combination of compounds (M-1-24) and (M-1-10) are preferred. Compound (M) can be produced by known methods.

[0072] The content of the UV dye (U) in the resin film is preferably such that the product of the total content of the dye (U) and the dye (A) and the thickness of the resin film is 100 (mass%·μm) or less, more preferably 80 (mass%·μm) or less, still more preferably 70 (mass%·μm) or less, and particularly preferably 50 (mass%·μm) or less. When the addition amount of the UV dye increases, it causes a decrease in resin properties, and as a result, the adhesion with the dielectric multilayer film decreases. Also, the glass transition temperature of the resin drops, raising concerns about heat resistance. If the product of the total content of the dyes and the thickness of the resin film is within the above range, such problems can be prevented. Further, from the viewpoint of satisfying the desired spectral characteristics, the product of the content and the thickness is preferably 10 (mass%·μm) or more, more preferably 15 (mass%·μm) or more.

[0073] From the viewpoint of satisfying the above range, the content of the UV dye (U) in the resin film is preferably 5 to 25 parts by mass, more preferably 5 to 20 parts by mass with respect to 100 parts by mass of the resin. Within such a range, the above problems can be avoided without degrading the resin properties. <C

[0074] <NIR dye> In the optical filter of the present invention, the base material contains the above dye (U) and the dye (A). The dye (A) is a NIR dye having a maximum absorption wavelength at 600 to 800 nm in dichloromethane. By containing such a dye, infrared light can be effectively cut.

[0075] As the dye (A), 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, croconium dyes, tetra-dehydro-ocorin dyes, triphenylmethane dyes, aminium dyes and diimonium dyes is preferable.

[0076] The dye (A) preferably contains at least one dye selected from a squarylium dye, a phthalocyanine dye, and a cyanine dye. Among these NIR dyes, squarylium dyes and cyanine dyes are preferred from the viewpoint of spectral quality, and phthalocyanine dyes are preferred from the viewpoint of durability.

[0077] The squarylium dye is preferably a compound represented by the following formula (I):

[0078] [ka]

[0079] In the formula (I), the symbols are as follows: R 24 and R 26 are each independently a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group or an alkoxy group having 1 to 6 carbon atoms, an acyloxy group having 1 to 10 carbon atoms, -NR 27 R 28 (R 27 and R 28 are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or -C(=O)-R 29 (R 29 represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an aryl group having 6 to 11 carbon atoms, or an araryl group having 7 to 18 carbon atoms which may have a substituent and which may have an oxygen atom between the carbon atoms), -NHR 30 , or -SO2-R 30 (R 30 represents a hydrocarbon group having 1 to 25 carbon atoms, each of which may have one or more hydrogen atoms substituted with a halogen atom, a hydroxyl group, a carboxyl group, a sulfo group, or a cyano group, and which may contain an unsaturated bond, an oxygen atom, or a saturated or unsaturated ring structure between carbon atoms), or a group represented by the following formula (S): 41 , R 42 are independently a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 10 carbon atoms. k is 2 or 3.

[0080] [ka]

[0081] R 21 and R 22 , R 22 and R 25 , and R 21 and R 23 may be linked to each other to form, together with the nitrogen atom, 5- or 6-membered heterocycles A, B, and C, respectively.

[0082] R when heterocycle A is formed 21 and R 22 represents a divalent group -Q- to which they are bonded, which is an alkylene group or alkyleneoxy group in which a hydrogen atom may be substituted with an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an acyloxy group having 1 to 10 carbon atoms which may have a substituent.

[0083] R when heterocycle B is formed 22 and R 25 and R when heterocycle C is formed. 21 and R 23 are the divalent groups -X 1 -Y 1 - and -X 2 -Y 2 -(The side that is bonded to nitrogen is X 1 and X 2 ) as X 1 and X 2 are groups represented by the following formula (1x) or (2x), and Y 1 and Y 2 are each a group selected from the following formulas (1y) to (5y): 1 and X 2 are groups represented by the following formula (2x), Y 1 and Y 2 may each be a single bond, in which case there may be an oxygen atom between the carbon atoms.

[0084] [ka]

[0085] In formula (1x), four Z's each independently represent a hydrogen atom, a hydroxyl group, an alkyl group or an alkoxy group having 1 to 6 carbon atoms, or -NR 38 R 39 (R 38 and R 39 R each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. 31 ~R 36 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms, R 37 represents an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms.

[0086] R 27 , R 28 , R 29 , R 31 ~R 37 , R when not forming a heterocycle 21 ~R 23 , and R 25 may be bonded to any other of these to form a 5- or 6-membered ring. 31 and R 36 , R 31 and R 37 may be directly bonded.

[0087] When a heterocyclic ring is not formed, R 21 and R 22 are each independently a hydrogen atom, an alkyl group or aryl group having 1 to 6 carbon atoms which may have a substituent, or an aryl group or araryl group having 6 to 11 carbon atoms which may have a substituent. When no heterocycle is formed, R 23 and R 25 are each independently a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 6 carbon atoms.

[0088] As the compound (I), for example, a compound represented by formula (I-1) is preferred from the viewpoint of increasing the visible light transmittance.

[0089] [ka]

[0090] The symbols in formula (I-1) have the same definitions as those of the same symbols in formula (I), and the preferred embodiments are also the same.

[0091] In compound (I-1), X 1 As the group (2x), the group (2x) is preferred. 1 is preferably a single bond or a group (1y). 31 ~R 36 is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom or a methyl group. 1 -X 1 Specific examples of - include divalent organic groups represented by formulas (11-1) to (12-3).

[0092] -C(CH3)2-CH(CH3)- …(11-1) -C(CH3)2-CH2- …(11-2) -C(CH3)2-CH(C2H5)- …(11-3) -C(CH3)2-C(CH3)(nC3H7)- …(11-4) -C(CH3)2-CH2-CH2- …(12-1) -C(CH3)2-CH2-CH(CH3)- …(12-2) -C(CH3)2-CH(CH3)-CH2- …(12-3)

[0093] In addition, in compound (I-1), R 21 are more preferably independently a group represented by formula (4-1) or formula (4-2) from the viewpoints of solubility, heat resistance, and the steepness of the change in the spectral transmittance curve near the boundary between the visible region and the near-infrared region.

[0094] [ka]

[0095] In formula (4-1) and formula (4-2), R 71 ~R 75 are independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms.

[0096] In compound (I-1), R 24 From the viewpoint of increasing the transmittance of visible light, especially light with a wavelength of 430 to 550 nm, -NH-SO2-R 30 is preferred. In compound (I-1), R 24 -NH-SO2-R 30 The compound is shown in formula (I-12).

[0097] [ka]

[0098] R in compound (I-12) 23 and R 26 are each preferably a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms, and more preferably a hydrogen atom.

[0099] In compound (I-12), R 30 From the viewpoint of light resistance, R is preferably an alkyl group having 1 to 12 carbon atoms, which may be branched, an alkoxy group having 1 to 12 carbon atoms, which may be branched, or a hydrocarbon group having 6 to 16 carbon atoms and an unsaturated ring structure. Examples of the unsaturated ring structure include benzene, toluene, xylene, furan, and benzofuran. 30 are more preferably independently an alkyl group having 1 to 12 carbon atoms which may be branched or an alkoxy group having 1 to 12 carbon atoms which may be branched. 30 In each group represented by the formula (I), some or all of the hydrogen atoms may be substituted with halogen atoms, particularly fluorine atoms.

[0100] Compound (I) can be produced by known methods, for example, as described in U.S. Pat. No. 5,543,086, U.S. Patent Application Publication No. 2014 / 0061505, and WO 2014 / 088063.

[0101] Examples of the phthalocyanine dye include the phthalocyanine dyes described in Japanese Patent No. 5884953 and International Publication No. 2019 / 168090.

[0102] The cyanine dye is preferably a compound represented by the following formula (A1) or (A2).

[0103] [ka]

[0104] Here, the symbols in formulas (A1) and (A2) are as follows: R 101 ~R 109 and R 121 ~R 131 R each independently represents a hydrogen atom, a halogen atom, an alkyl group or alkoxy group having 1 to 15 carbon atoms which may have a substituent, or an aryl group having 5 to 20 carbon atoms. 110 ~ 114 and R 132 ~ 136 each independently represents a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 15 carbon atoms. X - indicates a monovalent anion. n1 and n2 each independently represent 0 or 1. -(CH2) n1 Carbocycles containing - and -(CH2) n2 A hydrogen atom bonded to a carbocyclic ring containing - may be substituted with a halogen atom, an alkyl group having 1 to 15 carbon atoms which may have a substituent, or an aryl group having 5 to 20 carbon atoms.

[0105] In formula (A1) and formula (A2), R102 ~R 105 , R 108 , R 109 , R 122 ~R 127 , R 130 and R 131 are each independently preferably a hydrogen atom, an alkyl or alkoxy group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms, and more preferably a hydrogen atom from the viewpoint of obtaining a high visible light transmittance.

[0106] In formula (A1) and formula (A2), R 110 ~R 114 and R 132 ~R 136 are each independently preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms, and more preferably a hydrogen atom from the viewpoint of obtaining a high visible light transmittance.

[0107] R 106 , R 107 , R 128 and R 129 are each independently preferably a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms (which may include a linear, cyclic, or branched alkyl group), more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. 106 and R 107 , R 128 and R 129 are preferably the same group.

[0108] R 101 and R 121 is preferably an alkyl group having 1 to 15 carbon atoms or an aryl group having 5 to 20 carbon atoms, and more preferably a branched alkyl group having 1 to 15 carbon atoms from the viewpoint of maintaining high visible light transmittance in the transparent resin as well as in the solution.

[0109] X - As for I - , BF4 - , PF6 - , ClO4 - or anions represented by formula (X1) or (X2), and preferably BF4- , or PF6 - is.

[0110] [ka]

[0111] In the following description, R 101 ~R 114 The part excluding (A1) is also called the skeleton (A1). The same applies to other dyes.

[0112] In formula (A1), a compound in which n1 is 1 is shown in formula (A11) below, and a compound in which n1 is 0 is shown in formula (A12) below.

[0113] [ka]

[0114] In formula (A11) and formula (A12), R 101 ~R 114 and X - is the same as in formula (A1). 115 ~R 120 R each independently represents a hydrogen atom, a halogen atom, an alkyl group or alkoxy group having 1 to 15 carbon atoms which may have a substituent, or an aryl group having 5 to 20 carbon atoms. 115 ~R 120 are each independently preferably a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms (which may include a linear, cyclic, or branched alkyl group), more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. 115 ~R 120 are preferably the same group.

[0115] In formula (A2), a compound in which n2 is 1 is shown in formula (A21) below, and a compound in which n2 is 0 is shown in formula (A22) below.

[0116] [ka]

[0117] In formula (A21) and formula (A22), R 121 ~R 136 and X - is the same as in formula (A2). 137 ~R 142 R each independently represents a hydrogen atom, a halogen atom, an alkyl group or alkoxy group having 1 to 15 carbon atoms which may have a substituent, or an aryl group having 5 to 20 carbon atoms. 137 ~R 142 are each independently preferably a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms (which may include a linear, cyclic, or branched alkyl group), more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. 137 ~R 142 are preferably the same group.

[0118] The dye (A1) and the dye (A2) can be produced by known methods, for example, as described in Dyes and Pigments 73 (2007) 344-352 and J. Heterocyclic Chem, 42, 959 (2005).

[0119] As for the content of the NIR dye (A) in the substrate, it is preferable that the product of the total content of the dye (U) and the dye (A) and the thickness of the resin film is within a specific range, as described above. In order to satisfy the above range, the content of the NIR dye (A) in the resin film is preferably 5 to 25 parts by mass, more preferably 5 to 20 parts by mass, per 100 parts by mass of the resin.

[0120] <Base material composition> The substrate in the present filter may have a single-layer structure or a multi-layer structure, and the material of the substrate is not particularly limited, and may be an organic or inorganic material as long as it is a transparent material that transmits visible light of 400 to 700 nm. When the substrate has a single layer structure, it is preferably a resin substrate made of a resin film containing a resin and a UV dye (U) and an NIR dye (A). When the substrate has a multilayer structure, it is preferable that a resin film containing the UV dye (U) and the NIR dye (A) is laminated on at least one main surface of the support, and in this case, the support is preferably made of a transparent resin or a transparent inorganic material.

[0121] The resin is preferably a transparent resin, such as polyester resin, acrylic resin, epoxy resin, enethiol resin, polycarbonate resin, polyether resin, polyarylate resin, polysulfone resin, polyethersulfone resin, polyparaphenylene resin, polyarylene ether phosphine oxide resin, polyamide resin, polyimide resin, polyamideimide resin, polyolefin resin, cyclic olefin resin, polyurethane resin, and polystyrene resin. These resins may be used alone or in combination of two or more. Among these, polyimide resin is preferred because of its excellent visible light transmittance and high glass transition temperature, which makes it less susceptible to thermal degradation of the dye.

[0122] As the transparent inorganic material, glass or crystalline material is preferred. Glasses that can be used for the support include absorption-type glasses (near-infrared absorbing glasses) containing copper ions in fluorophosphate glass or phosphate glass, soda-lime glass, borosilicate glass, alkali-free glass, and quartz glass. Absorption glasses are preferred depending on the purpose, and phosphate glass and fluorophosphate glass are preferred from the viewpoint of absorbing infrared light. When it is desired to capture a large amount of red light (600 to 700 nm), alkali glass, alkali-free glass, and quartz glass are preferred. Note that "phosphate glass" also includes silicophosphate glass, in which part of the glass skeleton is composed of SiO2.

[0123] The glass may be chemically strengthened glass obtained by ion exchange at a temperature equal to or lower than the glass transition point to exchange alkali metal ions (e.g., Li ions, Na ions) having a small ionic radius present on the main surface of the glass plate with alkali ions having a larger ionic radius (e.g., Na ions or K ions for Li ions, and K ions for Na ions).

[0124] Examples of crystalline materials that can be used for the support include birefringent crystals such as quartz, lithium niobate, and sapphire.

[0125] 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.

[0126] The resin film can be formed by dissolving or dispersing the dye (U) and dye (A), the resin or resin raw materials, and other optional components in a solvent to prepare a coating solution, applying the coating solution to a support, drying, and optionally curing the coating solution. The support may be the support included in the filter, or a peelable support used only when forming the resin film. The solvent may be any suitable dispersion medium or solvent capable of stably dispersing the dye (U) and dye (A).

[0127] The coating liquid may also contain a surfactant to prevent voids caused by microbubbles, depressions caused by the adhesion of foreign matter, and repellency during the drying process. For example, the coating liquid can be applied by dip coating, cast coating, or spin coating. After the coating liquid is applied to a support, a resin film is formed by drying. When the coating liquid contains raw materials for a transparent resin, it is further subjected to a curing treatment such as thermal curing or photocuring.

[0128] The resin film can also be produced in the form of a film by extrusion molding. When the substrate has a single-layer structure (resin substrate) consisting of a resin film containing the dye (U) and the dye (A), the resin film can be used as is as the substrate. When the substrate has a multi-layer structure (composite substrate) having a support and a resin film containing the dye (U) and the dye (A) laminated on at least one main surface of the support, the substrate can be produced by laminating this film on the support and integrating them by thermocompression bonding or the like.

[0129] The optical filter may have one resin film layer or two or more resin films. When the optical filter has two or more resin films, the layers may have the same or different configurations.

[0130] The thickness of the resin film is preferably 10 μm or less, more preferably 5 μm or less. When the substrate has a single layer structure (resin substrate) made of a resin film containing the dye (U) and the dye (A), the thickness of the resin film is preferably 10 μm or less, more preferably 5 μm or less. When the substrate has a multilayer structure (composite substrate) having a support and a resin film containing dye (U) and dye (A), the thickness of the resin film is 10 μm or less, more preferably 5 μm or less. When the resin film is made up of multiple layers, the total thickness of the layers is preferably 20 μm or less, more preferably 10 μm or less.

[0131] The shape of the substrate is not particularly limited, and may be a block, plate, or film. The thickness of the substrate is preferably 300 μm or less, more preferably 50 to 300 μm, and particularly preferably 70 to 300 μm, from the viewpoint of handling and warpage deformation that may occur when the dielectric multilayer film is formed and reliability fluctuates. When the substrate is a resin substrate containing a resin and a dye, the thickness of the substrate is preferably 120 μm or less from the viewpoint of reducing the height, and is preferably 50 μm or more from the viewpoint of reducing warpage during multilayer film formation.When the substrate is a composite substrate comprising a support and a resin film, the thickness is preferably 70 μm to 110 μm.

[0132] <Dielectric multilayer film> In this filter, the dielectric multilayer film is laminated as the outermost layer on at least one of the main surfaces of the substrate.

[0133] In this filter, at least one of the dielectric multilayer films is preferably designed as a near-infrared reflective layer (hereinafter also referred to as an NIR reflective layer), and the other of the dielectric multilayer films is preferably designed as an NIR reflective layer, a reflective layer having a reflection range other than the near-infrared range, or an anti-reflection layer.

[0134] The NIR reflective layer is a dielectric multilayer film designed to block light in the near-infrared region. The NIR reflective layer 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 film. The reflective region of the NIR reflective layer may include the light-shielding region of the resin film in the near-infrared region. The NIR reflective layer is not limited to NIR reflection characteristics, and may be appropriately designed to further block light in wavelength regions other than the near-infrared region, for example, the near-ultraviolet region.

[0135] The NIR reflective layer is composed of, for example, a dielectric multilayer film in which dielectric films with low refractive index (low refractive index film) and dielectric films with high refractive index (high refractive index film) are alternately laminated. The high refractive index film preferably has a refractive index of 1.6 or more, more preferably 2.2 to 2.5. Examples of materials for the high refractive index film include Ta2O5, TiO2, and Nb2O5. Of these, TiO2 is preferred in terms of film formability, reproducibility in refractive index, etc., and stability.

[0136] On the other hand, the low refractive index film preferably has a refractive index of less than 1.6, more preferably 1.45 or more and less than 1.55. Examples of materials for the low refractive index film include SiO2, SiO x N y In terms of reproducibility, stability, economy, etc. in film formation, SiO2 is preferred.

[0137] Furthermore, it is preferable that the transmittance of the NIR reflective layer changes sharply in the boundary wavelength region between the transmission region and the light-blocking region. For this purpose, the total number of laminated layers of the dielectric multilayer film constituting the reflective layer is preferably 15 or more, more preferably 25 or more, and even more preferably 30 or more. However, since a large total number of laminated layers can cause 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. Furthermore, the overall film thickness of the reflective layer is preferably 2 to 10 μm.

[0138] When the total number of layers and the film thickness of the dielectric multilayer film are within the above ranges, the NIR reflective layer satisfies the requirement for miniaturization, and the incidence angle dependency can be suppressed while maintaining high productivity. In addition, the dielectric multilayer film can be formed by, for example, a vacuum film formation process such as a CVD method, a sputtering method, or a vacuum deposition method, or a wet film formation process such as a spray method or a dipping method.

[0139] The NIR reflective layer may be a single layer (a group of dielectric multilayer films) that provides predetermined optical characteristics, or two layers that provide predetermined optical characteristics. When there are two or more layers, the reflective layers may have the same or different configurations. When there are two or more reflective layers, they are usually composed of multiple reflective layers with different reflection bands. When two reflective layers are provided, one may be a near-infrared reflective layer that blocks light in the short wavelength band of the near-infrared region, and the other may be 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.

[0140] 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. Antireflection layers are obtained by alternately laminating dielectric films, similar to reflective layers.

[0141] The filter may also include other components, such as a component (layer) that provides absorption by inorganic fine particles that control the transmission and absorption of light in a specific wavelength range. Specific examples of inorganic fine particles include ITO (indium tin oxide), ATO (antimony-doped tin oxide), cesium tungstate, and lanthanum boride. ITO fine particles and cesium tungstate fine particles have high transmittance for visible light and absorb light over a wide range of infrared wavelengths exceeding 1200 nm, and therefore can be used when blocking such infrared light is required.

[0142] When used in an imaging device such as a digital still camera, this filter can provide an imaging device with excellent color reproducibility. An imaging device using this filter includes a solid-state imaging element, an imaging lens, and this filter. This filter can be used, for example, by being placed 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. [Example]

[0143] Next, the present invention will be explained more specifically with reference to examples. Each optical property was measured using an ultraviolet-visible spectrophotometer (UH-4150, manufactured by Hitachi High-Technologies Corporation). Unless the incident angle is specified, the spectral characteristics are values ​​measured at an incident angle of 0 degrees (perpendicular to the main surface).

[0144] The dyes used in each example are as follows: Compounds 1 to 17 are UV dyes, and compound 18 is an NIR dye. Compound 1 (merocyanine compound): Synthesized with reference to Japanese Patent No. 6504176. Compound 2: Nikkafluor U1 manufactured by Nippon Chemical Industry Co., Ltd. was used. Compound 3 (cyanine compound): SMP-416 manufactured by Hayashibara Chemical Industry Co., Ltd. was used. Compound 4 (cyanine compound): SMP-370 manufactured by Hayashibara Chemical Industry Co., Ltd. was used. Compound 5 (cyanine compound): SMP-471 manufactured by Hayashibara Chemical Industry Co., Ltd. was used. Compound 6: Kayalight 408 manufactured by Nippon Kayaku Co., Ltd. was used. Compound 7: Kayalight B manufactured by Nippon Kayaku Co., Ltd. was used. Compound 8: Nikkafluor MCT manufactured by Nippon Chemical Industry Co., Ltd. was used. Compound 9 (merocyanine compound): Synthesized with reference to Japanese Patent No. 6504176. Compound 10 (merocyanine compound): Synthesized with reference to Japanese Patent No. 6504176. Compound 11 (benzoxazole compound): UVITEX OB, manufactured by Tokyo Chemical Industry Co., Ltd. Compound 12 (merocyanine compound): Synthesized with reference to Japanese Patent No. 6504176. Compound 13 (merocyanine compound): Synthesized with reference to Japanese Patent No. 6504176. Compound 14 (azo compound): Synthesized with reference to Japanese Patent No. 6256335. Compound 15 (merocyanine compound): Synthesized with reference to Japanese Patent No. 6504176. Compound 16 (triazine compound): Synthesized with reference to Japanese Patent No. 6256335. Compound 17 (merocyanine compound): Synthesized with reference to Japanese Patent No. 6504176. Compound 18 (squarylium compound): Synthesized with reference to Japanese Patent No. 6197940.

[0145] [ka]

[0146] [ka]

[0147] <Test A: Spectroscopic properties of UV dyes in dichloromethane> Each dye was dissolved uniformly in dichloromethane. The resulting solutions were measured using a spectrophotometer to determine the maximum absorption wavelength (λ max ) and the absolute value of the difference (UV70-UV10) between the wavelength UV10 when the transmittance was 10% and the wavelength UV70 when the transmittance was 70% in the wavelength range of 350 to 450 nm was measured. The results are shown in the table below.

[0148] [Table 5]

[0149] <Test B: Spectral characteristics of UV dye in resin> <Example 1-1> The UV dye of Compound 1 (2.5% by mass), the NIR dye of Compound 18 (2.3% by mass), and a polyimide resin (Polyimide Varnish C-3G30G manufactured by Mitsubishi Gas Chemical Company) diluted with an organic solvent (a mixed solvent of gamma-butyrolactone and cyclohexanone) were mixed together, and the polyimide solution and the dyes were thoroughly dissolved. The obtained resin solution was applied to a glass substrate (alkali glass, Shotto D263) by spin coating, and the organic solvent was removed by sufficient heating to form a dye-containing polyimide thin film with a thickness of 5 μm. The resulting thin film was measured for transmission spectroscopy in the wavelength range of 350 nm to 1200 nm at an incident angle of 0° using a spectrophotometer. The results are shown in the table below.

[0150] <Example 1-2 to Example 1-16> A dye-containing resin thin film was prepared in the same manner as in Example 1-1, except that the type of UV dye, the amount of UV dye added, the amount of NIR dye added, and the thickness of the resin thin film were set to the values ​​shown in the table below, and the transmission spectrum was measured. The results are shown in the table below.

[0151] Examples 1-2, 1-5 to 1-11, 1-15, and 1-16 are working examples, and Examples 1-1, 1-3, 1-4, and 1-12 to 1-14 are comparative examples. T 440-480 : Average transmittance (%) in the spectral transmittance curve for wavelengths of 440 to 480 nm400-440 : Average transmittance (%) in the spectral transmittance curve for wavelengths of 400 to 440 nm 370-400 : Average transmittance (%) in the spectral transmittance curve for wavelengths of 370 to 400 nm 400 : Transmittance (%) on the spectral transmittance curve at a wavelength of 400 nm 390 : Transmittance (%) on the spectral transmittance curve at a wavelength of 390 nm 380 : Transmittance (%) on the spectral transmittance curve at a wavelength of 380 nm 370 : Transmittance (%) on the spectral transmittance curve at a wavelength of 370 nm

[0152] [Table 6]

[0153] From the above results, Examples 1-2, 1-5 to 1-11, 1-15, and 1-16, which used UV dyes with a maximum absorption wavelength in dichloromethane in the range of 360 to 395 nm, exhibited high blue light transmittance and ultraviolet light blocking properties, and exhibited excellent spectral characteristics. Example 1-16, which used a combination of two types of UV dyes, exhibited particularly excellent spectral characteristics. Example 1-2 exhibited excellent spectral characteristics, but it was necessary to increase the content of UV dye and the thickness of the resin film to obtain the desired spectral characteristics.

[0154] <Example 2-1: Spectral characteristics of optical filters> An ultraviolet and infrared cut multilayer film with a transmission band of 400 nm to 700 nm was formed on a glass substrate (alkali glass, Shotto D263). A resin thin film (absorption film) similar to that in Example 1-1 was formed on the multilayer film by spin coating. Then, a dielectric multilayer film (anti-reflection film) composed of SiO2 and TiO2 was formed on the resin thin film by vapor deposition, creating an absorption-type infrared cut filter. The transmission spectrum of the obtained infrared cut filter was measured using a spectrophotometer in the wavelength range of 350 nm to 1200 nm at incident angles of 0° and 50°. The results are shown in the table below.

[0155] <Examples 2-2 to 2-15> An infrared cut filter was prepared in the same manner as in Example 2-1, except that the type of UV dye, the amount of UV dye added, the amount of NIR dye added, and the thickness of the resin thin film were set to the values ​​shown in the table below, and the transmission spectrum was measured. The results are shown in the table below.

[0156] 5 shows the spectral transmittance curve of the infrared cut filter of Example 2-14, and Fig. 6 shows the spectral transmittance curve of the infrared cut filter of Example 2-15. Note that the solid line is the spectral transmittance curve for an incident direction of 0°, and the dashed line is the spectral transmittance curve for an incident direction of 50°.

[0157] Examples 2-5, 2-6, 2-9, 2-10, and 2-15 are working examples, and Examples 2-1 to 2-4, 2-7, 2-8, and 2-11 to 2-14 are comparative examples.

[0158] λ max : Maximum absorption wavelength (nm) T 440-480 : Average transmittance (%) in the spectral transmittance curve for wavelengths of 440 to 480 nm 400-440 : Average transmittance (%) in the spectral transmittance curve for wavelengths of 400 to 440 nm 370-400(0deg) : Average transmittance (%) in the spectral transmittance curve at an incident angle of 0 degrees and wavelengths of 370 to 400 nm 370-400(50deg) Average transmittance (%) of the spectral transmittance curve at an incident angle of 50 degrees and a wavelength of 370 to 400 nm. (0deg) : Wavelength (nm) UV10 when transmittance is 10% at wavelengths of 350 to 450 nm and an incident angle of 0 degrees (50deg) : Wavelength (nm) UV20 when transmittance is 10% at wavelengths of 350 to 450 nm and an incident angle of 50 degrees (0deg) : Wavelength (nm) when transmittance is 20% at wavelengths of 350 to 450 nm and an incident angle of 0 degrees UV20 (50deg) : Wavelength (nm) UV50 when transmittance is 20% at a wavelength of 350 to 450 nm and an incident angle of 50 degrees (0deg) : Wavelength (nm) when transmittance is 50% at wavelengths of 350 to 450 nm and an incident angle of 0 degrees. UV50 (50deg): Wavelength (nm) UV70 when transmittance is 50% at wavelengths of 350 to 450 nm and an incident angle of 50 degrees (0deg) : Wavelength (nm) when transmittance is 70% at a wavelength of 350 to 450 nm and an incident angle of 0 degrees | UV70 (0deg) -UV10 (0deg) |:UV10 (0deg) and UV70 (0deg) Absolute value of difference between |UV10 (50deg) -UV10 (0deg) |:UV10 (0deg) and UV10 (50deg) Absolute value of difference (nm) | UV20 (50deg) -UV20 (0deg) |:UV20 (0deg) and UV20 (50deg) Absolute value of difference (nm) |UV50 (50deg) -UV50 (0deg) |:UV50 (0deg) and UV50 (50deg) Absolute value of difference (nm)

[0159] [Table 7]

[0160] From the above results, the optical filters of Examples 2-5, 2-6, 2-9, 2-10, and 2-15, which used UV dyes whose maximum absorption wavelength in dichloromethane was in the range of 360 to 395 nm and whose solution spectrum (UV70-UV10) in Test A and in-resin spectrum (Test B) were within the specified ranges, exhibited high blue light transmittance and high ultraviolet light blocking properties even at high incident angles, and exhibited excellent spectral characteristics. Example 2-15, which used a combination of two types of UV dyes, exhibited particularly excellent spectral characteristics. On the other hand, the optical filters of Examples 2-1, 2-3, 2-4, 2-12, 2-13, and 2-14, which do not satisfy the range of maximum absorption wavelengths, and the optical filters of Examples 2-2, 2-7, 2-8, and 2-11, whose solution spectroscopy in Test A was not within the specified range, showed low transmittance for blue light or low blocking ability for ultraviolet light at high incident angles.

[0161] <Example 3-1: Lightfastness evaluation> Compound 1 UV dye (7.5% by mass), Compound 13 UV dye (3.5% by mass), Compound 18 NIR dye (7% by mass), and polyimide resin (Mitsubishi Gas Chemical Company, Polyimide Varnish C-3G30G) diluted with an organic solvent (a mixed solvent of gamma-butyrolactone and cyclohexanone) were mixed to thoroughly dissolve the polyimide solution and dyes. The amount of dye added indicates the amount added to the resin. The obtained solution was applied onto a glass substrate (alkali glass, Shotto D263) by spin coating, and the organic solvent was removed by sufficient heating to prepare a dye-containing polyimide film with a thickness of 1.5 μm. An antireflection film similar to that in Example 2-1 was formed on the obtained polyimide film by vapor deposition. The obtained optical sample was subjected to a light resistance test using a Super Xenon Weather Meter manufactured by Suga Test Instruments Co., Ltd. The incident surface was the antireflection film surface. The light intensity is 80,000 J / mm in wavelength range of 300 to 2450 nm. 2 The remaining rate of the NIR dye was calculated from the absorption coefficients at 400 nm and 680 nm before and after the light resistance test. The results are shown in the table below. In addition, if the survival rate at 400 nm (T400nm survival rate) was 85% or more and the survival rate at 680 nm (T680nm survival rate) was 75% or more, the light resistance was considered to be excellent.

[0162] <Examples 3-2 to 3-10: Lightfastness Evaluation> A light resistance test was carried out in the same manner as in Example 3-1, except that the type and content of the dye were set to the values ​​shown in the table below. The results are shown in the table below.

[0163] Examples 3-1 to 3-4, 3-5, and 3-7 to 3-10 are working examples, and Example 3-6 is a comparative example.

[0164] [Table 8]

[0165] From the above results, comparing Example 3-6 with Examples 3-4 to 3-5, it can be seen that when a UV dye and an NIR dye coexist, the NIR dye tends to deteriorate. However, as shown in Examples 3-1 to 3-3, it can be seen that the deterioration of the NIR dye can be suppressed by using a combination of multiple merocyanine compounds as the UV dye.

[0166] 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. 2020-126700) filed on July 27, 2020, the contents of which are incorporated herein by reference. [Industrial Applicability]

[0167] The optical filter of the present invention has good ultraviolet light blocking properties, in which the deterioration of ultraviolet light blocking properties, particularly at high incident angles, is suppressed while maintaining good near-infrared light blocking properties and good visible light transmittance, particularly blue light transmittance, and is therefore useful for applications in information acquisition devices, such as cameras and sensors for transport aircraft, which have been becoming increasingly high-performance in recent years. [Explanation of symbols]

[0168] 1A, 1B, 1C, 1D...optical filter, 10...substrate, 11...support, 12...resin film, 30...dielectric multilayer film

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 film containing a dye (U) having a maximum absorption wavelength in dichloromethane at 360 to 385 nm, a dye (A) having a maximum absorption wavelength in dichloromethane at 600 to 800 nm, and a resin; the dye (U) is a dye (U1) having a maximum absorption wavelength in dichloromethane at 370 to 385 nm, the resin film further contains a dye (U2) having a maximum absorption wavelength in dichloromethane at 385 to 405 nm; the absolute value of the difference between the maximum absorption wavelengths of the dyes (U1) and (U2) in the resin is 10 nm or more and 15 nm or less; The optical filter satisfies all of the following spectral characteristics (i-1) to (i-4): (i-1) Average transmittance T in the spectral transmittance curve for wavelengths of 440 to 480 nm ４４０－４８０ Over 86% (i-2) The wavelength at which the transmittance is 10% at a wavelength of 350 to 450 nm and an incident angle of 0 degrees is called UV10. （０ｄｅｇ） , the wavelength when the transmittance is 20% is UV20 （０ｄｅｇ） The wavelength at which the transmittance is 50% is called UV50. （０ｄｅｇ） year, The wavelength at which the transmittance is 10% at a wavelength of 350 to 450 nm and an incident angle of 50 degrees is called UV10. （５０ｄｅｇ） , the wavelength when the transmittance is 20% is UV20 （５０ｄｅｇ） The wavelength at which the transmittance is 50% is called UV50. （５０ｄｅｇ） When UV10 （０ｄｅｇ） and UV10 （５０ｄｅｇ） The absolute value of the difference is 3 nm or less, UV20 （０ｄｅｇ） and UV20 （５０ｄｅｇ） The absolute value of the difference is 4 nm or less, UV50 （０ｄｅｇ） and UV50 （５０ｄｅｇ） The absolute value of the difference is 4 nm or less (i-3) Average transmittance T in the spectral transmittance curve for wavelengths of 400 to 440 nm ４００－４４０ More than 40% (i-4) Average transmittance T in the spectral transmittance curve at a wavelength of 370 to 400 nm and an incident angle of 0 degrees ３７０－４００（０ｄｅｇ） is less than 1%

2. 2. The optical filter according to claim 1, wherein the optical filter further satisfies the following spectral characteristic (i-5): (i-5) Average transmittance T in the spectral transmittance curve at a wavelength of 370 to 400 nm and an incident angle of 50 degrees ３７０－４００（５０ｄｅｇ） is 0.5% or less

3. 3. The optical filter according to claim 1, wherein the optical filter further satisfies the following spectral characteristic (i-6): (i-6) The wavelength at which the transmittance is 10% at a wavelength of 350 to 450 nm and an incident angle of 0 degrees is called UV10. （０ｄｅｇ） The wavelength at which the transmittance is 70% is called UV70. （０ｄｅｇ） When UV10 （０ｄｅｇ） and UV70 （０ｄｅｇ） The absolute value of the difference is 16 nm or less

4. 4. The optical filter according to claim 1, wherein the resin film has a thickness of 10 μm or less.

5. The optical filter according to any one of claims 1 to 4, wherein the dye (U) satisfies all of the following spectral characteristics (ii-1) to (ii-6) in a spectral transmittance curve of a coating film formed by dissolving the dye (U) in the resin and coating the coating film on an alkali glass plate: (ii-1) Average transmittance T at wavelengths of 400 to 440 nm ４００－４４０ (ii-2) Average transmittance T at wavelengths of 370 to 400 nm ３７０－４００ is less than 5% (ii-3) Transmittance T at a wavelength of 400 nm ４００ is less than 7% (ii-4) Transmittance T at a wavelength of 390 nm ３９０ is less than 5% (ii-5) Transmittance T at a wavelength of 380 nm ３８０ is less than 5% (ii-6) Transmittance T at a wavelength of 370 nm ３７０ is less than 5%

6. 6. The optical filter according to claim 1, comprising two or more types of the dye (U).

7. The optical filter according to any one of claims 1 to 6, wherein the substrate has a support, and the support is any one of phosphate glass, fluorophosphate glass, alkali glass, non-alkali glass, and quartz glass.

8. 8. The optical filter according to claim 1, wherein the resin film is a single layer.

9. 8. The optical filter according to claim 1, wherein the resin film has two or more layers.

10. An imaging device comprising the optical filter according to any one of claims 1 to 9.

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