Optical filter

Abstract

The present invention aims to provide an optical filter that exhibits excellent transmittance of visible light and specific near-infrared light, while blocking other near-infrared light. [Solution] The present invention relates to an optical filter comprising a substrate and a dielectric multilayer film laminated on at least one main surface side of the substrate, wherein the substrate has a resin film containing a dye (I) having a maximum absorption wavelength of 690 to 900 nm in dichloromethane and a resin, and the optical filter transmits visible light and light in at least a portion of the wavelength range of 900 to 1000 nm, and satisfies all of the following spectral characteristics (i-1), (i-3) to (i-4) and (i-6).

Description

[Technical Field]

[0001] The present invention relates to an optical filter that transmits visible light and specific near-infrared light, while blocking light between these two regions. [Background technology]

[0002] Imaging devices using solid-state image sensors have expanded their applications to include surveillance cameras and in-vehicle cameras, which capture images day and night. Such devices require the acquisition of both visible light-based (color) images and infrared-based (black and white) images.

[0003] Therefore, in addition to the near-infrared cut filter function that transmits visible light and faithfully reproduces images based on that visible light, the use of optical filters equipped with a function that selectively transmits specific near-infrared light, so-called dual-bandpass filters, is being considered (Patent Documents 1 and 2). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2016-200771 [Patent Document 2] Japanese Patent Application Publication No. 2019-124946 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, the optical filters described in Patent Documents 1 and 2 selectively transmit visible light and near-infrared light in the 800-900 nm range, but do not transmit near-infrared light beyond 900 nm. In recent years, sensors that detect human eye and body movements have been using laser light around 950nm, so there is a need for optical filters that can transmit some near-infrared light from 900nm onwards while blocking other near-infrared light that would cause noise.

[0006] The present invention aims to provide an optical filter that is excellent in the transmittance of visible light and specific near-infrared light and can block other near-infrared light.

Means for Solving the Problems

[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 side of the substrate, where the substrate has a resin film containing a dye (I) having a maximum absorption wavelength in dichloromethane at 690 to 900 nm and a resin, and the optical filter transmits visible light and light in at least a part of the wavelength region of 900 to 1000 nm and satisfies all of the following spectral characteristics (i-1), (i-3) to (i-4), and (i-6). (i-1) The maximum transmittance T in the spectral transmittance curve at a wavelength of 700 to 900 nm and an incident angle of 0 degrees , 850-930(50deg) , ,

[0008] , 450-600(0deg)AVE , , 850-930(50deg) , , is 7% or less (i-3) Let the shortest wavelength at which the transmittance becomes 10% in the spectral transmittance curve at a wavelength of 900 to 950 nm and an incident angle of 0 degrees be IR10 900-950(0deg) and the shortest wavelength at which the transmittance becomes 70% be IR70 900-950(0deg) When this is done, IR70 900-950(0deg) -IR10 900-950(0deg) is 20 nm or less (i-4) Let the shortest wavelength at which the transmittance becomes 10% in the spectral transmittance curve at a wavelength of​​​​​​​​​​​​​​​​​​​​According to the present invention, an optical filter can be provided that exhibits excellent transmittance of visible light and specific near-infrared light, particularly in the wavelength range of 900 to 1000 nm, excellent shielding of other near-infrared light, particularly in the wavelength range of 700 to 900 nm, and furthermore, suppresses the decrease in shielding performance of near-infrared light at high incidence angles. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic cross-sectional view showing an example of an optical filter according to one embodiment. [Figure 2] Figure 2 is a schematic cross-sectional view showing another example of an optical filter according to one embodiment. [Figure 3] Figure 3 is a schematic cross-sectional view showing another example of an optical filter according to one embodiment. [Figure 4] Figure 4 is a schematic cross-sectional view showing another example of an optical filter according to one embodiment. [Figure 5] Figure 5 shows the spectral transmittance curve of the dielectric multilayer film in Example 2-1. [Figure 6] Figure 6 shows the spectral transmittance curve of the optical filter in Example 3-1. [Figure 7] Figure 7 shows the spectral transmittance curve of the optical filter in Example 3-4. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below. In this specification, near-infrared absorbing dyes may be abbreviated as "NIR dyes," and ultraviolet absorbing dyes may be abbreviated as "UV dyes." In this specification, the 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, the 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, internal transmittance is defined by the formula {measured transmittance / (100-reflectance)}×100, which is the transmittance obtained by subtracting the effect of interfacial reflection from the measured transmittance. In this specification, the transmittance of a substrate, the transmittance of a resin film (including cases where the dye is contained in the resin), and the spectral transmission measured by dissolving the dye in a solvent such as dichloromethane all refer to "internal transmittance" even when the term "transmittance" is used. On the other hand, the transmittance of an optical filter having a dielectric multilayer film is the measured transmittance.

[0012] In this specification, for a particular wavelength range, a transmittance of, for example, 90% or more means that the transmittance does not fall below 90% across the entire wavelength range, i.e., the minimum transmittance in that wavelength range is 90% or more. Similarly, for a particular wavelength range, a transmittance of, for example, 1% or less means that the transmittance does not exceed 1% across the entire wavelength range, i.e., the maximum transmittance in that wavelength range is 1% or less. The same applies to internal transmittance. The average transmittance and average internal transmittance in a particular wavelength range are the arithmetic mean of the transmittance and internal transmittance for every 1 nm in that wavelength range. Optical properties can be measured using an ultraviolet-visible spectrophotometer. In this specification, the symbol "~" used to indicate a numerical range includes both upper and lower limits.

[0013] <Optical filters> An optical filter according to one embodiment of the present invention (hereinafter also referred to as "this filter") comprises a substrate and a dielectric multilayer film laminated as the outermost layer on at least one main surface side of the substrate, and is an optical filter that satisfies specific spectral characteristics described later. Here, the substrate has a resin film containing a dye (I) having a maximum absorption wavelength of 690-900 nm in dichloromethane, and a resin. Dye (I) is an NIR dye. By containing a dye that absorbs near-infrared light in the substrate, the deterioration of the spectral characteristics of the dielectric multilayer film at high incidence angles, such as light loss and noise in the near-infrared region, can be suppressed by the absorption characteristics of the substrate. Each dye and resin will be described later.

[0014] An example of the configuration of this filter will be explained using the drawings. Figures 1 to 4 are schematic cross-sectional views showing an example of an optical filter according to one embodiment. The optical filter 1A shown in Figure 1 is an example in which a dielectric multilayer film 30 is provided on one main surface side of the substrate 10. Note that "having a specific layer on the main surface side of the substrate" is not limited to cases where the layer is in contact with the main surface of the substrate, but also includes cases where another functional layer is provided between the substrate and the layer.

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

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

[0017] The optical filter 1D shown in Figure 4 is an example in which the substrate 10 has a support 11 and a resin film 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 optical filter of the present invention transmits visible light and light in at least a portion of the wavelength range of 900 to 1000 nm, and satisfies all of the following spectral characteristics (i-1) to (i-6). (i-1) Maximum transmittance T in the spectral transmittance curve at wavelengths of 700-900 nm and an incident angle of 0 degrees 700-900(0deg)MAX less than 7% (i-2) Maximum transmittance T in the spectral transmittance curve at wavelengths of 700-850 nm and an incident angle of 50 degrees 700-850(50deg)MAX less than 5% (i-3) The shortest wavelength at which the transmittance is 10% in the spectral transmittance curve at wavelengths of 900-950 nm and an incident angle of 0 degrees is IR10. 900-950(0deg) The shortest wavelength at which the transmittance is 70% is IR70. 900-950(0deg) In that case, IR70 900-950(0deg) -IR10900-950(0deg) less than 20nm (i-4) The shortest wavelength at which the transmittance is 10% in the spectral transmittance curve at wavelengths of 850-930 nm and an incident angle of 50 degrees is IR10. 850-930(50deg) The shortest wavelength at which the transmittance is 70% is IR70. 850-930(50deg) In that case, IR70 850-930(50deg) -IR10 850-930(50deg) 50nm or less (i-5) The shortest wavelength at which the transmittance is 50% in the spectral transmittance curve at wavelengths of 850 nm or greater and at an incident angle of 0 degrees is IR50. 850(0deg) The shortest wavelength at which the transmittance is 50% at an incident angle of 50 degrees is defined as IR50. 850(50deg) In that case, IR50 850(0deg) and IR50 850(50deg) The absolute value of the difference is less than 30 nm. (i-6) Average transmittance T in the spectral transmittance curve at wavelengths of 450-600 nm and an incident angle of 0 degrees 450-600(0deg)AVE over 60%

[0019] This filter, which satisfies all of the spectral characteristics (i-1) to (i-6), is an optical filter that exhibits excellent transmittance of visible light and specific near-infrared light, while blocking other near-infrared light, and further suppresses the decrease in near-infrared light shielding performance at high incidence angles.

[0020] Satisfying spectral characteristics (i-1) means that it has excellent shielding properties in the 700-900 nm range. 700-900(0deg)MAX The amount is preferably 6.5% or less, and more preferably 6% or less.

[0021] Satisfying spectral characteristics (i-2) means that excellent shielding performance is achieved in the 700-850 nm range even at high incidence angles. 700-850(50deg)MAX The amount is preferably 4.5% or less, and more preferably 4% or less.

[0022] Satisfying spectral characteristic (i-3) means that the slope of the spectral transmission curve is steep in the NIR absorption band at wavelengths of 900 to 950 nm. Spectral characteristic (i-3) is preferably 18.5 nm or less, more preferably 17 nm or less.

[0023] Satisfying spectral characteristic (i-4) means that the slope of the spectral transmission curve is steep in the NIR absorption band of wavelengths 850-930 nm, even at high incidence angles. Spectral characteristic (i-4) is preferably 47.5 nm or less, more preferably 45 nm or less.

[0024] Satisfying the spectral characteristics (i-5) means that in the NIR absorption band above 850 nm wavelength, there is little shift even at high incident angles, and color reproduction is excellent. The spectral characteristics (i-5) are preferably 29 nm or less, more preferably 28 nm or less.

[0025] Satisfying the spectral characteristics (i-6) means that it has excellent transmittance in the visible light region. 450-600(0deg)AVE Preferably, it is 75% or more, more preferably 78% or more.

[0026] The optical filter preferably further satisfies the following spectral characteristics (i-7). (i-7) Average transmittance T in the spectral transmittance curve at wavelengths of 930-950 nm and an incident angle of 0 degrees. 930-950(0deg)AVE over 70%

[0027] Satisfying the spectral characteristics (i-7) means that it exhibits excellent transmittance in the near-infrared light region with wavelengths of 930-950 nm. 930-950(0deg)AVE Preferably, it is 74% or more, more preferably 78% or more.

[0028] <Base material> In the optical filter of the present invention, the substrate has a resin film containing the NIR dye (I) and resin described later.

[0029] <Spectral properties of resin films> The resin film preferably satisfies all of the following spectral characteristics (ii-1) to (ii-5). (ii-1) Average internal transmittance T in the spectral transmittance curve at wavelengths of 450-600 nm 450-600AVE over 80% (ii-2) The wavelength IR50 at which the internal transmittance is 50% is in the range of 620-660 nm. (ii-3) Average internal transmittance T in the spectral transmittance curve at wavelengths of 700-830 nm 700-830AVE less than 5% (ii-4) Maximum internal transmittance T in the spectral transmittance curve at wavelengths of 720-830 nm 720-830MAX less than 10% (ii-5) When the smallest wavelength at which the internal transmittance is 20% in the wavelength range of 850 to 950 nm is defined as IR20, and the smallest wavelength at which the internal transmittance is 80% is defined as IR80, The absolute difference between IR20 and IR80 is 50 nm or less.

[0030] Satisfying spectral characteristics (ii-1) means that the light exhibits excellent transmittance in the visible light region. T 450-600AVE Preferably, it is 82.5% or more, more preferably 85% or more.

[0031] By satisfying the spectral characteristics (ii-2), it is possible to compensate for the oblique incidence shift of a dielectric multilayer film that exhibits excellent transmittance in the red band and excellent light shielding in the near-infrared region of wavelengths from 750 to 900 nm. IR50 is preferably in the range of 620 to 655 nm, more preferably 625 to 650 nm.

[0032] Satisfying spectral characteristics (ii-3) means that it exhibits excellent shielding properties in the near-infrared light region with wavelengths of 700-830 nm. 700-830AVE The amount is preferably 4% or less, and more preferably 3% or less.

[0033] Satisfying spectral characteristics (ii-4) means that it exhibits excellent shielding properties in the near-infrared light region with wavelengths of 720-830 nm. 720-830MAXis preferably 8.5% or less, more preferably 7% or less.

[0034] By satisfying the spectral characteristic (ii-5), it means that the slope of the spectral transmittance curve is steep in the NIR absorption band with a wavelength of 850 to 950 nm. The spectral characteristic (ii-5) is preferably 47.5 nm or less, more preferably 45 nm or less.

[0035] <NIR dye> The NIR dye (I) is a NIR dye having a maximum absorption wavelength in dichloromethane at 690 to 900 nm. By containing such a dye, near-infrared light can be effectively cut.

[0036] The dye (I) preferably satisfies the following characteristic (iii-1) in the spectral internal transmittance curve measured by dissolving the dye (I) in the resin so that the internal transmittance at the maximum absorption wavelength in the resin constituting the resin film becomes 10%. (iii-1) When the maximum absorption wavelength is D [nm] and the average internal transmittance at 450 to 600 nm is E, E > 103.5 - (D / 100)

[0037] The characteristic (iii-1) defines the relationship between the maximum absorption wavelength and the transmittance. When the dye (I) satisfies the above characteristic (iii-1), it means that the transmittance in the visible light region of 450 to 600 nm is high at any maximum absorption wavelength.

[0038] The NIR dye (I) may consist of one type of compound, or may contain two or more compounds having a maximum absorption wavelength in dichloromethane at 690 to 900 nm. From the viewpoint of efficiently blocking the light between the two regions of visible light and the specific near-infrared light transmitted through this filter, it is preferable to contain three or more compounds having a maximum absorption wavelength in dichloromethane at 690 to 900 nm. In particular, it is more preferable to contain at least one compound selected from each of the compounds (A) to (C) having the following characteristics. Compound (A) having a maximum absorption wavelength in dichloromethane at a wavelength of 690 nm or more and less than 735 nm Compound (B) having a maximum absorption wavelength in dichloromethane between 735 nm and 830 nm. Compounds (C) having a maximum absorption wavelength in dichloromethane between 830 nm and 900 nm.

[0039] Compound (A) is preferably at least one selected from squarylium dyes, phthalocyanine dyes, and cyanine dyes. Compound (B) is preferably at least one selected from squarylium dyes, phthalocyanine dyes, and cyanine dyes. Compound (C) is preferably at least one selected from squarylium dye, phthalocyanine dye, cyanine dye, and diimonium dye.

[0040] As the NIR dye (I), squarylium dye or cyanine dye is preferred from the viewpoint of visible light transmittance, solubility in resin, and durability.

[0041] <Squalirium pigment> The squarylium dye is preferably a compound represented by the following formula (I) or formula (II). Furthermore, if two or more identical symbols exist in a squarylium dye compound, these symbols may be identical or different. The same applies to cyanine dyes.

[0042] <Squallium compound (I)>

[0043] [ka]

[0044] However, the symbols in the above formula are as follows: R 24 and R 26Each of these independently consists of a hydrogen atom, a halogen atom, a hydroxyl group, a C1-C20 alkyl or alkoxy group, a C1-C10 acyloxy group, a C6-C11 aryl group, a C7-C18 alaryl group which may have substituents and may have oxygen atoms between carbon atoms, and -NR 27 R 28 (R 27 and R 28 These are, independently, a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, and -C(=O)-R 29 (R 29 (This may include hydrogen atoms, halogen atoms, hydroxyl groups, hydrocarbon groups having 1 to 25 carbon atoms that may have substituents, unsaturated bonds between carbon atoms, oxygen atoms, or saturated or unsaturated ring structures), -NHR 30 , or -SO2-R 30 (R 30 (R) represents a hydrocarbon group having 1 to 25 carbon atoms, in which each hydrogen atom may be substituted with a halogen atom, hydroxyl group, carboxyl group, sulfo group, or cyano group, and which may contain unsaturated bonds, oxygen atoms, or saturated or unsaturated ring structures between carbon atoms. ) or a group represented by the following formula (S) (R) 41 , R 42 k independently represents a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 10 carbon atoms. k is 2 or 3.

[0045] [ka]

[0046] R 21 and R 22 , R 22 and R 25 , and R 21 and R 23 These may be linked together to form heterocycles A, B, and C, respectively, with nitrogen atoms, each having a membership of 5 or 6. R when a heteroalgebra A is formed 21 and R 22This represents an alkylene group or alkylene oxy group in which the 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 that may have substituents, as the divalent group -Q- to which these are bonded. R when a heteroalgebra B is formed 22 and R 25 , and R when a heterocyclic ring C is formed 21 and R 23 These are the divalent groups -X to which they are bonded. 1 -Y 1 -and -X 2 -Y 2 -(The side that bonds to nitrogen is X) 1 and X 2 ) as X 1 and X 2 These are the groups represented by the following formulas (1x) or (2x), and Y 1 and Y 2 Each of these is a group represented by one of the following formulas (1y) to (5y). 1 and X 2 However, in the case of the base represented by the following formula (2x), Y 1 and Y 2 Each of these may be a single bond, in which case there may be an oxygen atom between the carbon atoms.

[0047] [ka]

[0048] In formula (1x), the four Zs are each independently a hydrogen atom, a hydroxyl group, an alkyl or alkoxy group having 1 to 6 carbon atoms, or -NR 38 R 39 (R 38 and R 39 Each of these independently represents either a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. 31 ~R 36 Each independently comprises a hydrogen atom, a C1-C6 alkyl group, or a C6-C10 aryl group, R 37represents an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms. R 27 、R 28 、R 29 、R 31 ~R 37 When not forming a heterocyclic ring, R 21 ~R 23 、およびR 25 may combine with any one of the others to form a 5-membered or 6-membered ring. R 31 とR 36 、R 31 とR 37 may be directly bonded. When not forming a heterocyclic ring, R 21 、R 22 、R 23 およびR 25 each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group or an alkoxy group having 1 to 20 carbon atoms, an acyloxy group having 1 to 10 carbon atoms, an aryl group having 6 to 11 carbon atoms, or an aralkyl group having 7 to 18 carbon atoms which may have a substituent and may have an oxygen atom between carbon atoms.

[0049] Examples of the compound (I) include compounds represented by any of the formulas (I-1) to (I-3). From the viewpoints of solubility in a resin, heat resistance and light resistance in the resin, and visible light transmittance of a resin layer containing the same, the compound represented by the formula (I-1) is particularly preferable.

[0050]

Chemical formula

[0051] The symbols in the formulas (I-1) to (I-3) are the same as the respective definitions of the same symbols in the formula (I), and the preferred embodiments are also the same.

[0052] <0\000620>In the compound (I-1), X 1 is preferably the group (2x), and Y 1 is preferably a single bond or the group (1y). In this case, R 31 ~R36 Preferably, it is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom or a methyl group. 1 -X 1 Specifically, examples include the divalent organic groups shown in formulas (11-1) to (12-3).

[0053] -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)

[0054] Furthermore, in compound (I-1), R 21 From the viewpoint of solubility, heat resistance, and the steepness of the change near the boundary between the visible and near-infrared regions in the spectral transmittance curve, the group represented by formula (4-1) or (4-2) is independently more preferred.

[0055] [ka]

[0056] In equations (4-1) and (4-2), R 71 ~R 75 This independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms.

[0057] In compound (I-1), R 24 -NR 27 R 28 Preferably. -NR 27 R 28 From the perspective of solubility in resins and coating solvents, -NH-C(=O)-R 29 or -NH-SO2-R30 It is preferable.

[0058] In compound (I-1), R 24 -NH-C(=O)-R 29 The compound is shown in formula (I-11).

[0059] [ka]

[0060] R 23 and R 26 These are preferably, independently, a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 6 carbon atoms, with a hydrogen atom being more preferred in any case.

[0061] R 29 Preferred substituents include C1-C20 alkyl groups which may have substituents, C6-C10 aryl groups which may have substituents, or C7-C18 alaryl groups which may have substituents and may have oxygen atoms between carbon atoms. Examples of substituents include hydroxyl groups, carboxyl groups, sulfo groups, cyano groups, C1-C6 alkyl groups, C1-C6 fluoroalkyl groups, C1-C6 alkoxy groups, and C1-C6 acyloxy groups.

[0062] R 29 Preferably, the group is selected from linear, branched, or cyclic alkyl groups having 1 to 17 carbon atoms, phenyl groups which may be substituted with alkoxy groups having 1 to 6 carbon atoms, and alaryl groups having 7 to 18 carbon atoms which may have oxygen atoms between carbon atoms.

[0063] R 29 As an example, groups that are hydrocarbon groups having 5 to 25 carbon atoms and having at least one branch may also be used, in which one or more hydrogen atoms may be independently substituted with a hydroxyl group, a carboxyl group, a sulfo group, or a cyano group, and which may contain unsaturated bonds, oxygen atoms, or saturated or unsaturated ring structures between carbon atoms.

[0064] More specifically, compounds (I-11) include those listed in the table below. Furthermore, in the compounds listed in the table below, the meaning of each symbol is the same on both the left and right sides of the squarylium skeleton.

[0065] [Table 1]

[0066] Among these, compounds (I-11-11) to (I-11-15), (I-11-26) to (I-11-30), etc., are preferred as compound (I-11) in terms of transmittance in the visible light range and solubility in resin.

[0067] In compound (I-1), R 24 NH-SO2-R 30 The compound is shown in formula (I-12).

[0068] [ka]

[0069] R 23 and R 26 These are preferably, independently, a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 6 carbon atoms, with a hydrogen atom being more preferred in any case.

[0070] R 30 From the viewpoint of light resistance, it is preferable to have a branched alkyl or alkoxy group having 1 to 12 carbon atoms, or a hydrocarbon group having 6 to 16 carbon atoms with an unsaturated ring structure. Examples of unsaturated ring structures include benzene, toluene, xylene, furan, and benzofuran. 30 Independently, a branched alkyl or alkoxy group having 1 to 12 carbon atoms is more preferable. 30 In each of the groups exhibiting this characteristic, some or all of the hydrogen atoms may be substituted with halogen atoms, particularly fluorine atoms.

[0071] More specifically, compounds (I-12) include those listed in the table below. Furthermore, in the compounds listed in the table below, the meaning of each symbol is the same on both the left and right sides of the squarylium skeleton.

[0072] [Table 2]

[0073] Among these, compounds (I-12-11) to (I-12-15), (I-12-26) to (I-12-30), etc., are preferred as compound (I-12) in terms of transmittance in the visible light range and solubility in resin.

[0074] <Squallium compound (II)>

[0075] [ka]

[0076] However, the symbols in the above formula are as follows: Each ring Z is independently a 5-membered or 6-membered ring having 0 to 3 heteroatoms in the ring, and the hydrogen atoms in ring Z may be substituted. R 1 and R 2 , R 2 and R 3 , and R 1 The carbon atoms or heteroatoms constituting ring Z may be linked to each other and form heterorings A1, B1, and C1, respectively, together with the nitrogen atom, in which case the hydrogen atoms in heterorings A1, B1, and C1 may be substituted. 1 and R 2 Each of these independently represents a hydrocarbon group which may contain an unsaturated bond, heteroatom, saturated or unsaturated ring structure between a hydrogen atom, a halogen atom, or carbon atoms, and which may have substituents. 4 and R when it does not form a heterocycle 3Each of these independently represents an alkyl or alkoxy group which may contain a hydrogen atom, a halogen atom, or a heteroatom between carbon atoms, and which may have substituents.

[0077] Examples of compound (II) include compounds represented by any of formulas (II-1) to (II-3), and from the viewpoint of solubility in the resin and visible light transmittance in the resin, the compound represented by formula (II-3) is particularly preferred.

[0078] [ka]

[0079] In formula (II-1) and formula (II-2), R 1 and R 2 Each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 15 carbon atoms which may have substituents, and R 3 ~R 6 Each of these independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms, which may have substituents.

[0080] In formula (II-3), R 1 , R 4 , and R 9 ~R 12 Each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 15 carbon atoms which may have substituents, and R 7 and R 8 Each of these independently represents a hydrogen atom, a halogen atom, or a C1-C5 alkyl group which may have substituents.

[0081] R in compound (II-1) and compound (II-2) 1 and R 2 From the viewpoint of solubility in resin, visible light transmittance, etc., an alkyl group having 1 to 15 carbon atoms is preferred, and an alkyl group having 7 to 15 carbon atoms is more preferred, R 1 and R 2 At least one of them is more preferably an alkyl group having a branched chain with 7 to 15 carbon atoms, R1 and R 2 Alkyl groups having branched chains with 8 to 15 carbon atoms are particularly preferred for both.

[0082] R in compound (II-3) 1 From the viewpoint of solubility in transparent resins and visible light transmittance, alkyl groups having 1 to 15 carbon atoms are preferred, alkyl groups having 1 to 10 carbon atoms are more preferred, and ethyl groups and isopropyl groups are particularly preferred.

[0083] R 4 From the viewpoint of visible light transmittance and ease of synthesis, hydrogen atoms and halogen atoms are preferred, with hydrogen atoms being particularly preferred. R 7 and R 8 The following are preferred independently: a hydrogen atom, a halogen atom, and a C1-C5 alkyl group which may be substituted with a halogen atom; a hydrogen atom, a halogen atom, and a methyl group are more preferred.

[0084] R 9 ~R 12 The following are preferred independently: a hydrogen atom, a halogen atom, and a C1-C5 alkyl group which may be substituted with a halogen atom. -CR 9 R 10 -CR 11 R 12 -Examples include the divalent organic groups represented by the following groups (13-1) to (13-5). -CH(CH3)-C(CH3)2- …(13-1) -C(CH3)2-CH(CH3)- …(13-2) -C(CH3)2-CH2- …(13-3) -C(CH3)2-CH(C2H5)- …(13-4) -CH(CH3)-C(CH3)(CH2-CH(CH3)2)-…(13-5)

[0085] More specifically, compounds (II-3) include those shown in the table below. Furthermore, in the compounds shown in the table below, the meaning of each symbol is the same on both the left and right sides of the squarylium skeleton.

[0086] [Table 3]

[0087] Compounds (I) and (II) can each be prepared by known methods. Compound (I) can be prepared by the methods described in U.S. Patent No. 5,543,086, U.S. Patent Publication No. 2014 / 0061505, and International Publication No. 2014 / 088063. Compound (II) can be prepared by the methods described in International Publication No. 2017 / 135359.

[0088] <Cyanine pigment> The cyanine dye is preferably a compound represented by formula (III), formula (IV), formula (V), or formula (VI) below.

[0089] <Cyanine compounds (III), (IV)>

[0090] [ka]

[0091] However, the symbols in the above formula are as follows: R 101 ~R 109 and R 121 ~R 131 Each of these independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 15 carbon atoms which may have substituents, or an aryl group having 5 to 20 carbon atoms. 110 ~R 114 and R 132 ~R 136 These independently represent a hydrogen atom, a halogen atom, and an alkyl group having 1 to 15 carbon atoms. X - This indicates a monovalent anion. n1 and n2 are either 0 or 1. -(CH2) n1 -Carbon rings containing -(CH2) n2The hydrogen atom bonded to the carbon ring containing - may be substituted with a halogen atom, a C1-C15 alkyl group which may have substituents, or a C5-C20 aryl group.

[0092] In the above, the alkyl group (including the alkyl group of the alkoxy group) may be linear, branched, or saturated. The aryl group is a group that is bonded via carbon atoms constituting the aromatic ring of an aromatic compound, such as a benzene ring, naphthalene ring, biphenyl, furan ring, thiophene ring, pyrrole ring, etc. Substituents in C1-C15 alkyl or alkoxy groups, or C5-C20 aryl groups, which may have substituents, include halogen atoms and C1-C10 alkoxy groups.

[0093] In equations (III) and (IV), R 101 and R 121 The alkyl group is preferably a C1-C15 alkyl group or a C5-C20 aryl group, and a branched C1-C15 alkyl group is more preferred from the viewpoint of maintaining high visible light transmittance in the resin.

[0094] In equations (III) and (IV), R 102 ~R 105 , R 108 , R 109 , R 122 ~R 127 , R 130 and R 131 Each of these is preferably an independent hydrogen atom, an alkyl or alkoxy group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms, with hydrogen atoms being more preferred from the viewpoint of obtaining high visible light transmittance.

[0095] In equations (III) and (IV), R 110 ~R 114 and R 132 ~R 136 Each of these is preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms, with hydrogen atoms being more preferred from the viewpoint of obtaining high visible light transmittance.

[0096] R 106 , R 107 , R 128 and R 129 Each of these is 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 linear, cyclic, or branched alkyl groups), and more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. 106 and R 107 , R 128 and R 129 The same group is preferable.

[0097] X - As for, I - BF4 - PF6 - ClO4 - Examples include anions represented by formulas (X1) and (X2), preferably BF4 - , or PF6 - That is the case.

[0098] [ka]

[0099] In the following explanation, in pigment (III), R 101 ~R 114 The part excluding this is also called the skeleton (III). The same applies to the pigment (IV).

[0100] In equation (III), compounds with n1 = 1 are shown in equation (III-1) below, and compounds with n1 = 0 are shown in equation (III-2) below.

[0101] [ka]

[0102] In equations (III-1) and (III-2), R 101 ~R 114 and X - This is the same as in the case of equation (III). R 115 ~R120 Each of these independently represents a hydrogen atom, a halogen atom, an alkyl or alkoxy group having 1 to 15 carbon atoms which may have substituents, or an aryl group having 5 to 20 carbon atoms. 115 ~R 120 Each of these is 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 linear, cyclic, or branched alkyl groups), and more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. 115 ~R 120 It is preferable that they are the same group.

[0103] In equation (IV), compounds with n² = 1 are shown in equation (IV-1) below, and compounds with n² = 0 are shown in equation (IV-2) below.

[0104] [ka]

[0105] In equations (IV-1) and (IV-2), R 121 ~R 136 and X - This is the same as in case (IV). 137 ~R 142 Each of these independently represents a hydrogen atom, a halogen atom, an alkyl or alkoxy group having 1 to 15 carbon atoms which may have substituents, or an aryl group having 5 to 20 carbon atoms. 137 ~R 142 Each of these is 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 linear, cyclic, or branched alkyl groups), and more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. 137 ~R 142 It is preferable that they are the same group.

[0106] More specifically, the compounds represented by formulas (III-1), (III-2), (IV-1), and (IV-2) are compounds in which the atoms or groups bonded to each skeleton are those shown in the table below. In all the compounds shown in the table below, R 101 ~R 109 The terms are identical on both sides of the equation. In all the compounds shown in the table below, R 121 ~R 131 The terms on both sides of the equation are identical.

[0107] R in the table below 110 -R 114 and R in the table below 132 -R 136 The symbol indicates the atom or group bonded to the central benzene ring in each formula, and "H" is written when all five are hydrogen atoms. 110 -R 114 If one of the atoms is a substituent and the others are hydrogen atoms, only the combination of the sign of the substituent and the substituent is listed. For example, "R 112 The description "-C(CH3)3" is R 112 This indicates that -C(CH3)3 and the others are hydrogen atoms. 132 -R 136 The same applies to this matter.

[0108] R in Table 4 115 -R 120 and R in Table 6 137 -R 142 R indicates the atom or group bonded to the central cyclohexane ring in formulas (III-1) and (IV-1), and is denoted as "H" if all six are hydrogen atoms. 115 -R 120 If one of the atoms is a substituent and the others are hydrogen atoms, only the combination of the sign of the substituent and the substituent is listed. 137 -R 142 The same applies to this matter.

[0109] R in Table 5 115 -R 118 and R in Table 7 137 -R 140R indicates the atom or group bonded to the central cyclopentane ring in formulas (III-2) and (IV-2), and is denoted as "H" if all four are hydrogen atoms. 115 -R 118 If one of the atoms is a substituent and the others are hydrogen atoms, only the combination of the sign of the substituent and the substituent is listed. 137 -R 140 The same applies to this matter.

[0110] The table below contains X - Although it does not show, X is present in all compounds. - is BF4 - or PF6 - That is the case.

[0111] [Table 4]

[0112] Among these, dyes (III-1-1) to (III-1-5) are preferred as dye (III-1) in terms of transmittance in the visible light range and solubility in resin.

[0113] [Table 5]

[0114] Among these, dyes (III-2-1) to (III-2-5) are preferred as dyes (III-2-2) in terms of transmittance in the visible light range and solubility in resin.

[0115] [Table 6]

[0116] Among these, dyes (IV-1-1) to (IV-1-5) are preferred as dye (IV-1) in terms of transmittance in the visible light range and solubility in resin.

[0117] [Table 7]

[0118] As the pigment (IV-2), among these, in terms of the transparency in the visible light region and the solubility in the resin, pigments (IV-2-1) to (IV-2-5) etc. are preferable.

[0119] In the pigment (III) and the pigment (IV), as described above, the skeletons are different, and thereby, the wavelength regions of the absorption maxima are different. In the pigment (III), although it also depends on the types and combinations of atoms and groups bonded to the skeleton, the maximum absorption wavelength is generally in the wavelength region of 760 to 830 nm. In the pigment (IV), although it also depends on the types and combinations of atoms and groups bonded to the skeleton, the maximum absorption wavelength is generally in the wavelength region of 800 to 900 nm.

[0120] Furthermore, in the pigment (III), the maximum absorption wavelength is different between the case where n1 of the skeleton is 1 and the case where n1 is 0. Although it also depends on the types and combinations of atoms and groups bonded to the skeleton, when n1 is 1, the maximum absorption wavelength is generally in the wavelength region of 760 to 800 nm, and when n1 is 0, the maximum absorption wavelength is generally in the wavelength region of 800 to 830 nm.

[0121] Similarly, in the pigment (IV) as well, the maximum absorption wavelength is different between the case where n2 is 1 and the case where n2 is 0. Although it also depends on the types and combinations of atoms and groups bonded to the skeleton (IV-1), when n2 is 1, the maximum absorption wavelength is generally in the wavelength region of 800 to 830 nm, and when n2 is 0, the maximum absorption wavelength is generally in the wavelength region of 830 to 900 nm.

[0122] The pigment (III) and the pigment (IV) can be produced, for example, by the methods described in Dyes and pigments 73(2007) 344-352 and J.Heterocyclic chem,42,959(2005).

[0123] <Cyanine compound (V)>

[0124]

Chemical formula

[0125] However, the symbols in equation (V) are as follows: R 1 ~R 7 Each of these is independently a hydrogen atom, a halogen atom, a sulfo group, a hydroxyl group, a cyano group, a nitro group, a carboxyl group, a phosphoric acid group, an alkyl group having 1 to 10 carbon atoms which may have substituents, an alkoxy group having 1 to 10 carbon atoms which may have substituents, or an acyloxy group having 1 to 10 carbon atoms which may have substituents. In equation (V), R 1 ~R 7 The terms on the left and right sides of the expression may be the same or different, but it is preferable that they are all the same.

[0126] Examples of substituents in C1-C10 alkyl, alkoxy, or acyloxy groups that may have substituents include halogen atoms or C1-C10 alkoxy groups.

[0127] Herein, unless otherwise specified, alkyl groups may be linear, branched, cyclic, or combinations thereof. The same applies to alkyl groups of alkoxy groups. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms, with fluorine and chlorine atoms being preferred.

[0128] R 1 From the viewpoint of ease of synthesis, etc., each of these is preferably a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group, or an acyloxy group, with a hydrogen atom being particularly preferred.

[0129] R 2 ~R 7Each of these is independently preferably a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms which may have substituents, an alkoxy group having 1 to 10 carbon atoms which may have substituents, or an acyloxy group having 1 to 10 carbon atoms which may have substituents. From the viewpoint of ease of synthesis, each of these is independently preferably a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have substituents, or an alkoxy group having 1 to 10 carbon atoms which may have substituents.

[0130] R 6 ~R 7 From the viewpoint of solubility in resins and solvents, at least one of the groups is preferably an alkyl group having 1 to 10 carbon atoms, more preferably a branched alkyl group of secondary or tertiary genus having 10 or fewer carbon atoms, and even more preferably a tertiary butyl group, an isopropyl group, or an isobutyl group.

[0131] R 2 ~R 5 , R 6 ~R 7 Two adjacent elements may be linked together to form a ring with 5 to 8 members. The ring may be aliphatic or aromatic.

[0132] Formula (V) optionally contains Z, which is a 5-membered or 6-membered ring. The presence of Z is preferable in terms of durability. The hydrogen atoms bonded to the carbon atoms constituting Z may be substituted with C1-C10 alkyl groups or C6-C10 aryl groups.

[0133] In this specification, unless otherwise specified, an aryl group refers to a group that is bonded via carbon atoms constituting an aromatic ring of an aromatic compound, such as a benzene ring, naphthalene ring, biphenyl ring, furan ring, thiophene ring, pyrrole ring, etc.

[0134] X - This indicates a monovalent anion. X - PF6 - [Rf-SO2] - [N(Rf-SO2)2] - , or BF4 -is preferred. Rf represents an alkyl group substituted with at least one fluorine atom, preferably a perfluoroalkyl group having 1 to 8 carbon atoms, and particularly preferably -CF3. Due to the anion having such a structure, a dye compound (V) with excellent light resistance can be obtained.

[0135] R 8 is a hydrogen atom, a halogen atom, or -Y 5 -R 10 (Y 5 is a single bond, an ether bond (-O-), a sulfonyl bond (-SO2-), an ester bond (-C(=O)-O- or -O-C(=O)-), or a ureido bond (-NH-C(=O)-NH-), and R 10 is an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 30 carbon atoms which may have a substituent. ).

[0136] R 8 is a hydrogen atom, a halogen atom, Y 5 where Y is a single bond, -Y 5 -R 10 is preferred, and a hydrogen atom, a chlorine atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms which may be substituted with a halogen atom is more preferred.

[0137] In formula (V), more specifically, compounds in which the atoms or groups bonded to each skeleton are as shown in the following table can be mentioned. In all the compounds shown in the following table, R 1 ~R 7 are the same on both the left and right sides of the formula.

[0138]

Table 8

[0139] [[ID=...]] Among these, as the compound (V), compounds (V-1) to (V-4), etc. are preferred from the viewpoints of visible light region transmittance and solubility in resins.

[0140] Regarding the production method of the compound (V), R in the compound (V) 1 It should be noted that there seems to be an incomplete tag in the original text for line ID 45. Also, for the sake of better readability in the translation, the line breaks are maintained as in the original while following the translation rules. If there are any specific requirements regarding the handling of such potential issues, further adjustments might be needed.~R 5 , R 7 X is a hydrogen atom, - BF4 - The method for producing compound (V1) will be explained using the following examples, but the method for producing compound (V1) is not limited to these. The pathway for obtaining compound (V1) is shown below.

[0141] [ka]

[0142] (1) Salicylaldehyde (a) and R 6 Compound (c) is obtained by reacting it with the alkyne compound (b) having the group. (2) Compound (d) is obtained by reacting compound (c) with 4-dimethylaminopyridine. (3) Compound (d) is reacted with methylmagnesium bromide and tetrafluoroboric acid to obtain compound (e). (4) Compound (e), R 8 Compound (V1) is obtained by reacting it with aldehyde dianilide hydrochloride (f), which has a group.

[0143] X - PF annotation - In that case, by using hexafluorophosphate instead of tetrafluoroboric acid in step (3) above, X - to [Rf-SO2] - In that case, by using Rf-SO3H instead of tetrafluoroboric acid in step (3) above, X - [N(Rf-SO2)2] - In that case, the respective compounds can be synthesized by using NH(Rf-SO2)2 instead of tetrafluoroboric acid in step (3) above.

[0144] <Cyanine compound (VI)>

[0145] [ka]

[0146] The symbols in equation (VI) are as follows:

[0147] X - It is a monovalent anionic species. For example, PF6 - BF4 - , N(SO2CF3)2 - CF3SO3 - ReO4 - ClO4 - Cl - , Br - , I - , BPh4 - , B(C6F5)4 - CF3COO - , C(SO2CF3)3 - Examples include p-toluenesulfonyl anions. Note that "Ph" stands for phenyl group.

[0148] Among these, from the viewpoint of improving the photoresistance of compound (VI), X - PF6 - BF4 - , N(SO2CF3)2 - It is preferable to select from among them.

[0149] m is 0 or 1, and is preferably 1. When m is 0, R1 is a monovalent anionic group. Examples of monovalent anionic groups include the anionic groups shown in any of the following (C1) to (C6).

[0150] [ka]

[0151] In formulas (C1) to (C6), R 201 ~R 214Each of these independently represents a hydrogen atom, an aryl group having 5 to 20 carbon atoms, or an alkyl group having 1 to 10 carbon atoms, which may have substituents. Examples of substituents include halogen atoms or alkoxy groups having 1 to 10 carbon atoms.

[0152] When m is 1, R1 is a hydrogen atom, a halogen atom, a C1-C12 alkyl group, an optionally substituted C6-C12 aryl group, an optionally substituted C7-C13 alaryl group, or -NR9R 10 That is the case.

[0153] Examples of halogen atoms in R1 include fluorine, chlorine, bromine, and iodine atoms.

[0154] The alkyl group in R1 preferably has 1 to 10 carbon atoms, and more preferably 1 to 6 carbon atoms. Examples of alkyl groups with 1 to 6 carbon atoms include methyl, ethyl, propyl, isopropyl, isobutyl, and tert-butyl groups. Among these, the methyl group is particularly preferred from a synthetic standpoint.

[0155] Examples of aryl groups with 6 to 12 carbon atoms in R1 include groups that are bonded via carbon atoms constituting aromatic rings (e.g., benzene rings, naphthalene rings, biphenyl rings, furan rings, thiophene rings, pyrrole rings, etc.) in aromatic compounds. Among these, the phenyl group is preferred from the viewpoint of not impairing transmittance in the blue spectrum.

[0156] Examples of the aryl group having 7 to 13 carbon atoms in R1 include linear or branched saturated or unsaturated hydrocarbon groups or saturated cyclic hydrocarbon groups that may contain a saturated ring structure and are substituted with one or more aryl groups. Among these, an alaryl group having a phenyl group is preferred from the viewpoint of not impairing transmittance in the blue band.

[0157] Examples of substituents that R1 may have include halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, iodine atoms), C1-C12 alkyl groups, C1-C12 alkoxy groups, hydroxyl groups, carboxyl groups, sulfo groups, cyano groups, amino groups, N-substituted amino groups, nitro groups, alkoxycarbonyl groups, carbamoyl groups, N-substituted carbamoyl groups, imide groups, and the like.

[0158] R9, R 10 Each of these is independently an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms which may have substituents, or a carbonyl group having 1 to 12 carbon atoms which may have substituents.

[0159] R9, R 10 Specific examples of alkyl and aryl groups in and R9, R 10 Specific examples of substituents that R1 may have are the same as those for R1.

[0160] R9, R 10 Examples of carbonyl groups having 1 to 12 carbon atoms in this context include acetyl, ethanol, propanoyl, benzoyl, trifluoroacetyl, and pentafluoroethanol groups.

[0161] Among these, R1 is preferably a hydrogen atom, a methyl group, a phenyl group, a diphenylamino group, an N-ethylamide group, or an N-ethyl-2,2,2-trifluoroacetamide group, and more preferably a hydrogen atom, a methyl group, or a phenyl group, from the viewpoint of not impairing the transmittance in the blue band and from a synthetic viewpoint.

[0162] R2 to R7 are each independently a hydrogen atom, a halogen atom, a C1-C12 alkyl group, a C3-C12 cycloalkyl group, an optionally substituted C6-C12 aryl group, or an optionally substituted C7-C13 aryl group. Two adjacent R2 to R7 may be linked to each other to form a 5-8 membered ring.

[0163] Specific examples of halogen atoms, alkyl groups, aryl groups having 6 to 12 carbon atoms, and aryl groups in R2 to R7, as well as specific examples of substituents that R2 to R7 may have, are the same as those for R1.

[0164] The number of carbon atoms in the cycloalkyl group in R2 to R7 is preferably 3 to 10, and more preferably 6 to 10. Examples of cycloalkyl groups with 6 to 10 carbon atoms include cyclohexyl group, cycloheptyl group, cyclooctyl group, and adamantyl group.

[0165] Among these, R2 to R5 are preferably hydrogen atoms or alkyl groups having 1 to 12 carbon atoms, and more preferably hydrogen atoms, from the viewpoint of not impairing transmittance in the blue band and from a synthetic viewpoint.

[0166] Furthermore, R6 to R7 are preferably C1 to C12 alkyl groups or C6 to C12 aryl groups which may have substituents, from the viewpoint of increasing transmittance in the blue band, more preferably C1 to C12 secondary alkyl groups, C1 to C12 tertiary alkyl groups, or phenyl groups which have substituents at positions 2 and 6, and even more preferably isopropyl groups, tert-butyl groups, sec-butyl groups, 2,6-dimethylphenyl groups, 2,4,6-trimethylphenyl groups, 2,6-diisopropylphenyl groups, or 2,4,6-triisopropylphenyl groups.

[0167] Furthermore, compound (VI) is more preferably a compound represented by the following formula (VI-1).

[0168] [ka]

[0169] The symbols in equation (VI-1) are as follows:

[0170] X - The definitions of R1 to R5 are the same as in equation (VI).

[0171] R 11 , R 12 Each of these is independently an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.

[0172] R 11 , R 12 The alkyl group in the compound preferably has 1 to 8 carbon atoms, and more preferably 1 to 5 carbon atoms. Examples of alkyl groups with 1 to 5 carbon atoms include methyl, ethyl, isopropyl, and tert-butyl groups.

[0173] R 11 , R 12 The number of carbon atoms in the alkoxy group is preferably 1 to 8, and more preferably 1 to 6. Examples of alkoxy groups with 1 to 6 carbon atoms include methoxy, ethoxy, and isopropoxy groups.

[0174] R 11 , R 12 Because the phenyl group is an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms, dye A adopts a conformation in which the phenyl group is orthogonal to the π-conjugation plane. This breaks the π-conjugation between the phenyl group and dye A, and the phenyl group becomes capable of inductive electron-withdrawal. Due to this electron-withdrawal effect, compound (VI-1) has absorption in the near-infrared region of 720 to 760 nm and can achieve high transmittance in the blue band.

[0175] Among these, R 11 , R 12 From a synthetic standpoint, it is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms, and even more preferably a methyl group, an ethyl group, or an isopropyl group.

[0176] R 13 This is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.

[0177] R 13The alkyl group in the compound preferably has 1 to 8 carbon atoms, and more preferably 1 to 5 carbon atoms. Examples of alkyl groups with 1 to 5 carbon atoms include methyl, ethyl, isopropyl, and tert-butyl groups.

[0178] R 13 The number of carbon atoms in the alkoxy group is preferably 1 to 8, and more preferably 1 to 6. Examples of alkoxy groups with 1 to 6 carbon atoms include methoxy, ethoxy, and isopropoxy groups.

[0179] Among these, R 13 From a synthetic standpoint, it is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms, and even more preferably a methyl group, an ethyl group, or an isopropyl group.

[0180] Also, R 13 If R is not a hydrogen atom, 13 R 11 , R 12 It is preferable from a synthetic standpoint that it be the same as [another compound].

[0181] More specifically, compound (VI-1) refers to compounds in which the atoms or groups bonded to each skeleton are those shown in the table below.

[0182] [Table 9]

[0183] Among these, compounds represented by formulas (VI-1-1) and (VI-1-2) are preferred from the viewpoint of ease of synthesis. Furthermore, from the viewpoint of improving the light resistance of compound (VI), X - PF6 - BF4 - , N(SO2CF3)2 - It is preferable to select from among them.

[0184] (Method for producing compound (VI)) The method for producing compound (VI) will be explained using the method for producing compound (VI-1-a), in which R1 to R5 in compound (VI-1) are hydrogen atoms, but the method for producing compound (VI) is not limited to these. The route for obtaining compound (VI-1-a) is shown below.

[0185] [ka]

[0186] <Step 1> Add the starting material (g), trimethylsilylacetylene, tetrakis(triphenylphosphine)palladium (0), copper iodide, and diethylamine to a round-bottom flask. After degassing the flask, replace with nitrogen and heat while stirring. After the reaction is complete, remove the solvent under reduced pressure, add water, and extract with dichloromethane. Remove the dichloromethane under reduced pressure and purify to obtain intermediate (h).

[0187] <Step 2> Add intermediate (h) and methanol to a round-bottom flask and cool with ice. Add potassium carbonate and stir under a nitrogen stream. After the reaction is complete, remove potassium carbonate from the reaction system by filtration, and remove the filtrate under reduced pressure. Add water to the resulting liquid and extract with dichloromethane. Remove the dichloromethane under reduced pressure and purify to obtain intermediate (i).

[0188] <Step 3> Add intermediate (i) and tetrahydrofuran to a round-bottom flask and stir under a nitrogen stream. Add n-butyllithium and stir. Then add ethyl formate dissolved in tetrahydrofuran and stir. After the reaction is complete, add water to stop the reaction and extract with dichloromethane. Remove the dichloromethane under reduced pressure, wash the resulting solid to obtain intermediate (j).

[0189] <Step 4> Add intermediate (j), dichloromethane, and manganese oxide to a round-bottom flask and stir under a nitrogen stream. After the reaction is complete, filter the reaction solution to remove manganese oxide, and remove the filtrate under reduced pressure. Wash the resulting powder to obtain intermediate (k).

[0190] <Step 5> In a round-bottom flask, add intermediate (k), p-toluenesulfonic acid monohydrate, methanol, and toluene, and stir. Then, remove the solvent under reduced pressure, add methanol and concentrated hydrochloric acid, and stir. After the reaction is complete, cool the reaction solution with ice, add water to stop the reaction, and then extract with dichloromethane. Remove the dichloromethane under reduced pressure, add toluene and trifluoromethanesulfonic acid, and stir. After the reaction is complete, cool the reaction solution with ice, add water to stop the reaction, and extract the toluene layer. Remove the toluene under reduced pressure, purify, wash the resulting powder, and obtain intermediate (l).

[0191] <Step 6> In a round-bottom flask, add intermediate (l) and tetrahydrofuran, stir, then add methylmagnesium bromide, and heat and stir under a nitrogen stream. After the reaction is complete, stop the reaction by gradually pouring the reaction solution into a 10% by mass acidic aqueous solution and stirring. Extract this solution with dichloromethane, wash the dichloromethane layer with water, and then remove the dichloromethane by distillation under reduced pressure. Wash the resulting powder to obtain intermediate (m).

[0192] Examples of 10% by mass acidic aqueous solutions include hexafluorophosphate aqueous solution, tetrafluoroboric acid aqueous solution, bis(trifluoromethanesulfonyl)imide aqueous solution, trifluoromethanesulfonic acid aqueous solution, perrhenium acid aqueous solution, perchloric acid aqueous solution, hydrochloric acid aqueous solution, hydrobromic acid aqueous solution, hydroiodic acid aqueous solution, and the like.

[0193] <Step 7> In a round-bottom flask, add the intermediate (m), malonaldehyde dianilide hydrochloride, sodium acetate, acetic acid, and acetic anhydride, and heat and stir under a nitrogen stream. After the reaction is complete, cool the reaction solution with ice, add water, and then filter the reaction solution to recover the powder. After purifying the powder, wash the resulting solid to obtain compound (VI-1-a).

[0194] The content of NIR dye (I) in the resin film is preferably 0.1 to 25 parts by mass, more preferably 0.3 to 15 parts by mass, per 100 parts by mass of resin. When two or more compounds are combined, the above content is the sum of the content of each compound.

[0195] <Other pigments> The resin film may contain other dyes besides NIR dyes, such as UV dyes. UV dyes include, specifically, oxazole, merocyanine, cyanine, naphthalimide, oxadiazole, oxazine, oxazolidine, naphthalic acid, styryl, anthracene, cyclic carbonyl, and triazole dyes. UV dyes may be used individually or in combination of two or more.

[0196] <Base material composition> The substrate in this filter may have a single-layer or multi-layer structure. Furthermore, the material of the substrate is not particularly limited; it may be an organic or inorganic material as long as it is a transparent material that transmits visible light in the 400-700 nm range. When the substrate has a single-layer structure, a resin substrate consisting of a resin film containing a resin and an NIR dye (I) is preferred. When the substrate has a multilayer structure, a composite substrate is preferred in which a resin film containing NIR dye (I) is laminated on at least one main surface of the support. In this case, the support is preferably made of a transparent resin or a transparent inorganic material.

[0197] The resin is not limited to transparent resins, and one or more transparent resins selected from polyester resin, acrylic resin, epoxy resin, ene-thiol resin, polycarbonate resin, polyether resin, polyarylate resin, polysulfone resin, polyethersulfone resin, poly-paraphenylene resin, polyarylene ether phosphine oxide resin, polyamide resin, polyimide resin, polyamide-imide resin, polyolefin resin, cyclic olefin resin, polyurethane resin, and polystyrene resin can be used. These resins may be used individually or in mixtures of two or more. From the viewpoint of the spectral properties of the resin film, glass transition temperature (Tg), and adhesion, one or more resins selected from polyimide resin, polycarbonate resin, polyester resin, and acrylic resin are preferred.

[0198] When multiple compounds are used as NIR dyes (I) or other dyes, they may be contained in the same resin film, or they may each be contained in separate resin films.

[0199] Glass and crystalline materials are preferred as transparent inorganic materials. Examples of glass that can be used as a support include phthalate glass, phosphate glass, and other absorption-type glass containing copper ions (near-infrared absorbing glass), soda-lime glass, borosilicate glass, alkali-free glass, and quartz glass.

[0200] As the glass, chemically strengthened glass may be used, obtained by ion exchange at a temperature below the glass transition temperature, in which alkali metal ions with small ionic radii (e.g., Li ions, Na ions) present on the main surface of the glass plate are replaced with alkali ions with larger ionic radii (e.g., Na ions or K ions for Li ions, and K ions for Na ions).

[0201] Examples of crystalline materials that can be used as supports include birefringent crystals such as quartz, lithium niobate, and sapphire.

[0202] As a support material, inorganic materials are preferred, particularly glass and sapphire, from the viewpoint of shape stability related to long-term reliability such as optical properties and mechanical properties, as well as handling during filter manufacturing.

[0203] The resin film can be formed by preparing a coating solution by dissolving or dispersing a dye (I), a resin or a raw material component of the resin, and other components as needed in a solvent, coating this solution onto a support, drying it, and further curing it as needed. The support may be the support included in this filter, or it may be a releaseable support used only when forming the resin film. The solvent may be any dispersion medium or solvent that can stably disperse or dissolve the components.

[0204] Furthermore, the coating solution may contain a surfactant to improve voids caused by minute bubbles, indentations caused by the adhesion of foreign matter, and repulsion during the drying process. In addition, methods such as immersion coating, cast coating, or spin coating can be used for applying the coating solution. After applying the above coating solution to the support, a resin film is formed by drying. Furthermore, if the coating solution contains raw material components of a transparent resin, a curing treatment such as thermosetting or photocuring is performed.

[0205] Furthermore, the resin film can also be manufactured in film form by extrusion molding. When the substrate is a single-layer structure (resin substrate) consisting of a resin film containing the dye (I), the resin film can be used as the substrate as is. When the substrate is a multi-layer structure (composite substrate) having a support and a resin film containing the dye (I) laminated on at least one main surface of the support, the substrate can be manufactured by laminating this film onto the support and integrating it by heat pressing or the like.

[0206] The resin film may be present as one layer within the optical filter, or as two or more layers. If there are two or more layers, each layer may have the same or different configuration.

[0207] The thickness of the resin film is preferably 20 to 150 μm when the substrate is a single-layer structure (resin substrate) consisting of a resin film containing dye (I). When the substrate is a multilayer structure (composite substrate) having a support and a resin film containing dye (I) laminated on at least one main surface of the support, the thickness of the resin film is preferably 0.3 to 20 μm. If the optical filter has two or more resin films, it is preferable that the total thickness of each resin film is within the above range.

[0208] The shape of the substrate is not particularly limited and may be in the form of a block, plate, or film. Furthermore, the thickness of the substrate is preferably 300 μm or less from the viewpoint of reducing warping during dielectric multilayer film formation and reducing the height of optical elements. When the substrate is a resin substrate consisting of a resin film, it is preferably 50 to 300 μm, and when the substrate is a composite substrate comprising a support and a resin film, it is preferably 50 to 300 μm.

[0209] This filter may also include other components, such as a component (layer) that provides absorption by inorganic nanoparticles that control the transmission and absorption of light in a specific wavelength range. Specific examples of inorganic nanoparticles include ITO (Indium Tin Oxides), ATO (Antimony-doped Tin Oxides), cesium tungstate, and lanthanum boride. ITO nanoparticles and cesium tungstate nanoparticles have high transmittance of visible light and light absorption over a wide range in the infrared wavelength region exceeding 1200 nm, and can therefore be used when shielding against such infrared light is required.

[0210] <Dielectric multilayer film> In this filter, the dielectric multilayer film is laminated as the outermost layer on at least one main surface side of the substrate.

[0211] In this filter, it is preferable that the dielectric multilayer film satisfies all of the following spectral characteristics (iv-1) to (iv-6). (iv-1) Average transmittance T at wavelengths of 450-600 nm 450-600AVE over 93% (iv-2) In the wavelength range of 600-800 nm, the wavelength VL50 at which the transmittance is 50% is in the range of 680-750 nm. (iv-3) Average transmittance T at wavelengths of 750-900 nm 750-900AVE less than 10% (iv-4) Wavelength IR50 at which the transmittance is 50% in the wavelength range of 850-950 nm 850-950 It is located at 900-930nm. (iv-5) Average transmittance T at wavelengths of 930-950 nm 930-950AVE over 80% (iv-6) Wavelength IR50 at which the transmittance is 50% in the wavelength range of 950 to 1100 nm. 950-1100 It is located at 1000-1080 nm.

[0212] Satisfying spectral characteristics (iv-1) means that the light transmittance in the visible light range is excellent. 450-600AVE The percentage is preferably 94% or more, and more preferably 95% or more.

[0213] Satisfying spectral characteristics (iv-2) means that the light source exhibits excellent transmittance in the red band and excellent light shielding in the near-infrared region with wavelengths of 750 to 900 nm. VL50 is preferably in the range of 685 to 750 nm, more preferably 690 to 750 nm.

[0214] Satisfying spectral characteristics (iv-3) means that it exhibits excellent light-shielding properties in the near-infrared region with wavelengths of 750-900 nm. 750-900AVE The percentage is preferably 8.5% or less, and more preferably 7% or less.

[0215] Satisfying spectral characteristics (iv-4) means that it exhibits excellent light-shielding properties in the near-infrared region of 750-900 nm and excellent transmittance in the near-infrared region of 930-950 nm. IR50 850-950 The wavelength is preferably in the range of 905 to 930 nm, and more preferably in the range of 910 to 930 nm.

[0216] Satisfying spectral characteristics (iv-5) means that it exhibits excellent transmittance in the near-infrared light region with wavelengths of 930-950 nm. 930-950AVE Preferably, it is 81.5% or more, more preferably 83% or more.

[0217] Satisfying spectral characteristics (iv-6) means that it exhibits excellent transmittance in the near-infrared region at wavelengths of 930-950 nm and excellent light shielding in the near-infrared region at wavelengths of 1080 nm and above. IR50 950-1100 The wavelength is preferably in the range of 1005 to 1080 nm, more preferably in the range of 1010 to 1075 nm.

[0218] In this filter, it is preferable that at least one of the dielectric multilayer films is designed as a near-infrared reflective layer (hereinafter also referred to as the NIR reflective layer). The other dielectric multilayer film is preferably designed as an NIR reflective layer, a reflective layer having a reflection region other than the near-infrared region, or an anti-reflective layer.

[0219] An NIR reflective layer is a dielectric multilayer film designed to block light in the near-infrared region. For example, an NIR reflective layer transmits visible light and specific near-infrared light, while exhibiting wavelength selectivity that primarily reflects light other than the light-blocking region of the absorbent resin film and the specific near-infrared light. The reflective region of the NIR reflective layer may also include the light-blocking region of the resin film in the near-infrared region. The NIR reflective layer may be designed to further block light in wavelengths other than the near-infrared region, such as the near-ultraviolet region, not just its NIR reflection characteristics.

[0220] The NIR reflective layer is composed of a dielectric multilayer film in which a low refractive index dielectric film (low refractive index film) and a high refractive index dielectric film (high refractive index film) are alternately stacked. The high refractive index film preferably has a refractive index of 1.6 or higher, and 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 formation properties, reproducibility in refractive index, stability, etc.

[0221] On the other hand, the low refractive index film preferably has a refractive index of less than 1.6, and more preferably 1.45 or more and less than 1.55. Examples of materials for the low refractive index film are SiO2, SiO2, and SiO2. x N y These are some examples. SiO2 is preferred in terms of reproducibility, stability, and cost-effectiveness in film formation.

[0222] For an NIR reflective layer to transmit visible light and specific near-infrared light, it is necessary to combine several dielectric multilayer films with different spectral characteristics to transmit and select the desired wavelength band. For example, this can be adjusted by the materials that make up the film, the film thickness of each layer, and the number of layers.

[0223] From the viewpoint of controlling the wavelength bands of transmission and light shielding, the NIR reflective layer preferably has a total number of layers of dielectric multilayer films constituting the reflective layer, preferably 50 layers or more, more preferably 90 layers or more, and even more preferably 130 layers or more. Furthermore, the thickness of the reflective layer is preferably 2 to 15 μm overall.

[0224] Furthermore, for the formation of dielectric multilayer films, vacuum deposition processes such as CVD, sputtering, and vacuum evaporation, as well as wet deposition processes such as spraying and dipping, can be used.

[0225] The NIR reflective layer may provide predetermined optical properties with a single layer (a group of dielectric multilayer films) or with two layers. If there are two or more layers, each reflective layer may have the same or different configuration. 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 shields light in the short-wavelength band of the near-infrared region, and the other may be a near-infrared / near-ultraviolet reflective layer that shields light in both the long-wavelength band of the near-infrared region and the near-ultraviolet region.

[0226] Examples of anti-reflective layers include dielectric multilayer films, intermediate refractive index media, and moth-eye structures with gradually changing refractive indices. Among these, dielectric multilayer films are preferred from the viewpoint of optical efficiency and productivity. The anti-reflective layer is obtained by alternately stacking dielectric multilayer films, similar to the reflective layer.

[0227] This filter, when used in imaging devices such as digital still cameras, can provide an imaging device with excellent color reproduction. An imaging device using this filter comprises a solid-state image sensor, an imaging lens, and this filter. This filter can be used, for example, by being placed between the imaging lens and the solid-state image sensor, or by being directly attached to the solid-state image sensor, imaging lens, etc. of the imaging device via an adhesive layer. [Examples]

[0228] Next, the present invention will be described in more detail with reference to examples. A UV-Vis spectrophotometer (Hitachi High-Technologies Corporation, UH-4150 model) was used to measure each optical characteristic. Note that unless the angle of incidence is specifically stated, the spectral characteristics are measured at an angle of incidence of 0 degrees (perpendicular to the main surface of the optical filter).

[0229] The dyes used in each example are as follows: Compound 1 (squallium dye): Synthesized according to U.S. Patent No. 5543086. Compound 2 (squallium dye): Synthesized according to U.S. Patent No. 5543086. Compound 3 (squallium dye): Synthesized based on U.S. Patent Application Publication No. 2014 / 0061505 and International Publication No. 2014 / 088063. Compound 4 (cyanine pigment): Synthesized according to Synthesis Example 1 described below. Compound 5 (squallium dye): Synthesized according to International Publication No. 2017 / 135359. Compound 6 (cyanine pigment): Synthesized by Synthesis Example 2 described below. Compounds 7, 8, and 9 (cyanine pigments) were synthesized based on Dyes and Pigments 73 (2007) 344-352. Compound 10: Synthesized according to Japanese Patent Publication No. 4081149. Compound 11: Synthesized based on International Publication No. 2020 / 129909. Compound 12: Synthesized according to Japanese Patent Publication No. 2014-25016.

[0230] [ka]

[0231] [ka]

[0232] [ka]

[0233] <Synthesis Example 1: Synthesis of Compound 4>

[0234] [ka]

[0235] <Step 1> In a 1000 mL round-bottom flask, mesityl iodide (100 g, 406.4 mmol), trimethylsilylacetylene (59.9 g, 609.5 mmol), tetrakis(triphenylphosphine)palladium(0) (6.1 g, 5.28 mmol), copper iodide (2.0 g, 10.6 mmol), and diethylamine (500 mL) were added. After degassing the flask, the contents were replaced with nitrogen and heated and stirred at 50°C for 6 hours. After the reaction was complete, the solvent was removed by vacuum distillation, water was added, and the mixture was extracted with dichloromethane. After removing the dichloromethane by vacuum distillation, the mixture was purified by flash column chromatography (hexane) to obtain 90.1 g (quant.) of intermediate ia. <Step 2> Intermediate ia (90.1 g, 416.4 mmol) and methanol (600 mL) were added to a 1 L round-bottom flask and cooled with ice. Potassium carbonate (167.9 g, 1214.8 mmol) was then added and the mixture was stirred at room temperature under a nitrogen stream for 1 hour. After the reaction was complete, the reaction solution was filtered through Celite to remove the potassium carbonate from the reaction system, and the filtrate was removed by vacuum distillation. Water was added to the resulting orange-yellow liquid and extracted with dichloromethane. After removing the dichloromethane by vacuum distillation, the solution was purified by flash column chromatography (hexane) to obtain 58.5 g (quant.) of intermediate ib. <Step 3> Intermediate ib (22.0 g, 152.6 mmol) and tetrahydrofuran (125 mL) were added to a 1000 mL round-bottom flask and stirred under a nitrogen stream at -78°C. Using a dropping funnel, n-butyllithium (1.6 mol / L in hexane) (100 mL) was added and stirred at -78°C for 1 hour. Then, ethyl formate (5.7 g, 76.3 mmol) dissolved in 20 mL of tetrahydrofuran was added using a dropping funnel and stirred at -78°C for 5 hours and at 0°C for 1.5 hours. After the reaction was complete, water was added to stop the reaction and the mixture was extracted with dichloromethane. After removing the dichloromethane under reduced pressure, the resulting yellowish-brown solid was washed with hexane to obtain 13.4 g (56%) of intermediate ic. <Step 4> In a 1000 mL round-bottom flask, intermediate ic (25.9 g, 83.7 mmol), dichloromethane (500 mL), and manganese oxide (36.4 g, 418.7 mmol) were added, and the mixture was stirred at room temperature under a nitrogen stream for 1 hour. After the reaction was complete, the reaction solution was filtered to remove the manganese oxide, and the filtrate was removed by distillation under reduced pressure. The resulting yellow powder was washed with hexane to obtain 23.6 g (92%) of intermediate id. <Step 5> In a 1000 mL round-bottom flask, intermediate id (21.9 g, 69.7 mmol), p-toluenesulfonic acid monohydrate (2.4 g, 13.9 mmol), methanol (230 mL), and toluene (230 mL) were added, and the mixture was stirred at 110 °C for 8 hours. The solvent was then removed by vacuum distillation, and methanol (280 mL) and concentrated hydrochloric acid (70 mL) were added. The mixture was stirred overnight at 70 °C. After the reaction was complete, the reaction solution was cooled on ice, water was added to stop the reaction, and the mixture was extracted with dichloromethane. After removing the dichloromethane by vacuum distillation, toluene (350 mL) and trifluoromethanesulfonic acid (21.0 g, 139.9 mmol) were added, and the mixture was stirred at 100 °C for 2.5 hours. After the reaction was complete, the reaction solution was cooled on ice, water was added to stop the reaction, and the toluene layer was extracted. After removing toluene under reduced pressure, the mixture was purified by flash column chromatography (hexane / dichloromethane) to obtain a pink powder. The resulting pink powder was washed with hexane to obtain 15.5 g (67%) of the intermediate ie. <Step 6> In a 500 mL round-bottom flask, intermediate ie (6.0 g, 18.0 mmol) and tetrahydrofuran (75 mL) were added and stirred at 0°C. Methylmagnesium bromide (13% tetrahydrofuran solution) (49.7 g, 54.1 mmol) was then added, and the mixture was heated and stirred at 70°C for 1 hour under a nitrogen stream. After the reaction was complete, the reaction solution was gradually added to 350 mL of 10% hexafluorophosphate aqueous solution at 0°C and stirred at 0°C for 10 minutes to stop the reaction. This solution was extracted with dichloromethane, the dichloromethane layer was washed with water, and the dichloromethane was removed by distillation under reduced pressure. The resulting yellow powder was washed with hexane to obtain 8.2 g (95%) of intermediate if. <Step 7> In a 200 mL round-bottom flask, intermediate if (1.75 g, 3.7 mmol), malonaldehyde dianilide hydrochloride (0.47 g, 1.84 mmol), sodium acetate (0.72 g, 8.82 mmol), acetic acid (15 mL), and acetic anhydride (15 mL) were added, and the mixture was heated and stirred at 80°C for 45 minutes under a nitrogen stream. After the reaction was complete, the reaction solution was cooled with ice, water was added, and the reaction solution was filtered to recover a dark green powder. The recovered powder was purified by flash column chromatography (dichloromethane / ethyl acetate), and the resulting solid was washed with a hexane:ethyl acetate = 1:1 solvent to obtain 1.4 g (88%) of compound 4.

[0236] <Synthesis Example 2: Synthesis of Compound 6>

[0237] [ka]

[0238] <Step 1> 3,3-dimethyl-1-butyne (13g, 160 mmol) and tetrahydrofuran (40 mL) were placed in a 1 L round-bottom flask, cooled to -78°C and stirred, and n-butyllithium (1.6 M in n-hexane, 100 mL) was added dropwise, and the mixture was stirred at -78°C for 1 hour. Then, salicylaldehyde (10g, 82 mmol) dissolved in tetrahydrofuran (80 mL) was added, and the mixture was stirred at room temperature for 3 hours. After the reaction was complete, saturated ammonium chloride aqueous solution was added to quench the mixture, and it was extracted with ethyl acetate. After removing the solvent, manganese dioxide (35g, 400 mmol) and acetone (80 mL) were added, and the mixture was stirred at room temperature for 16 hours. After the reaction was complete, the mixture was filtered to remove the solvent from the filtrate, and then purified by column chromatography to obtain 6.1 g (37%) of the intermediate ig. <Step 2> Into a 500 mL eggplant flask, intermediate ig (6.1 g, 30 mmol) and N,N-dimethylformamide (120 mL) were added. It was cooled and stirred at 0 °C, 4-dimethylaminopyridine (0.37 g, 3.0 mmol) was added, and the reaction was carried out at room temperature for 16 hours. After the reaction was completed, water was added for quenching, extracted with ethyl acetate, the solvent was removed, and then purified by column chromatography to obtain 4.2 g (70%) of intermediate ih. <Step 3> Into a 500 mL eggplant flask, intermediate ih (5.0 g, 25 mmol) was added, tetrahydrofuran (60 mL) was added, cooled and stirred at 0 °C, methylmagnesium bromide (1 M in tetrahydrofuran, 37 mL) was added dropwise, and the reaction was carried out at room temperature for 5 hours. After the reaction was completed, ice water was added for quenching, 60% aqueous solution of hexafluorophosphoric acid in hexane (150 mL) was added, and stirred at room temperature for 30 minutes. Extracted with dichloromethane, the solvent was removed, and the precipitated solid was washed with ethyl acetate to obtain 7.2 g (84%) of intermediate ii. <Step 4> Into a 500 mL eggplant flask, intermediate ii (5.2 g, 15 mmol), malondialdehyde dianilide hydrochloride (1.9 g, 7.5 mmol), sodium acetate (3.0 g, 36 mmol), acetic acid (60 mL), and acetic anhydride (60 mL) were added, and stirred at 80 °C for 2 hours. After the reaction was completed, water was added, the precipitated solid was filtered and recovered, and purified by column chromatography to obtain 1.8 g (41%) of compound 6.

[0239] <Spectral Characteristics of IR Dye> A polyimide resin (C-3G30G manufactured by Mitsubishi Gas Chemical) was dissolved in an organic solvent (cyclohexanone:γ-butyrolactone = 1:1 mass ratio) at a concentration of 8.5% by mass. To the solution of the polyimide resin prepared above, each dye compound was added so that it became 6 parts by mass per 100 parts by mass of the resin, and stirred for 2 hours while heating to 50 °C. The dye-containing resin solution was applied to a glass substrate (alkali glass, D263 manufactured by Schott), and dried to obtain a resin film (coated film) with a film thickness of 1 μm. Using the spectral transmittance curve and spectral reflectance curve of this resin-coated glass plate, the spectral internal transmittance curve was calculated and normalized so that the transmittance at the maximum absorption wavelength was 10%. The spectral characteristics are shown in the table below.

[0240] [Table 10]

[0241] <Examples 1-1 to 1-6: Spectral characteristics of resin films> Polyimide resin (C-3G30G, manufactured by Mitsubishi Gas Chemical Co., Ltd.) was dissolved in an organic solvent (cyclohexanone:γ-butyrolactone = 1:1 mass ratio) at a concentration of 8.5% by mass. To the polyimide resin solution prepared above, each compound was added in the amounts (parts by mass) shown in the table below per 100 parts by mass of resin, and the mixture was stirred for 2 hours while heating at 50°C. The dye-containing resin solution was applied to a glass substrate (alkali glass, Schott D263) and dried to obtain a resin film (coated film) with a thickness of 3 μm. The spectral characteristics are shown in the table below. Examples 1-1 to 1-6 are for reference only.

[0242] [Table 11]

[0243] Examples 1-1 to 1-3 exhibit a wide absorption range in the near-infrared region and high visible light transmittance. Examples 1-4 have a narrow absorption width in the near-infrared region. Examples 1-5 show a relatively narrow absorption width in the near-infrared region. Examples 1-6 show a broad absorption range in the near-infrared region but low visible light transmittance. This is likely because increasing the amount of compound (B) added broadened the absorption range, resulting in absorption in the visible light region as well.

[0244] <Example 2-1: Spectroscopic properties of dielectric multilayer films> A reflective layer was designed consisting of a 69-layer dielectric multilayer film 1 and a 76-layer dielectric multilayer film 2, in which TiO2 and SiO2 films are alternately stacked. The combined spectral characteristics of dielectric multilayer film 1 and dielectric multilayer film 2 are shown in the table below. Furthermore, Figure 5 shows the spectral transmittance curve of dielectric multilayer film 1 and dielectric multilayer film 2 combined. Note that Example 2-1 is for reference only.

[0245] [Table 12]

[0246] <Example 3-1: Optical properties of an optical filter> An optical filter was obtained by stacking the dielectric multilayer film 2 prepared in Example 2-1, a glass substrate (alkali glass, Schott D263), the resin film from Example 1-1, and the dielectric multilayer film 1 prepared in Example 2-1 in this order.

[0247] <Examples 3-2 to 3-5: Optical properties of optical filters> An optical filter was obtained in the same manner as in Example 3-1, except that the resin film was as shown in the table below.

[0248] The spectral characteristics are shown in the table below. Furthermore, the spectral transmittance curves for the optical filter in Example 3-1 are shown in Figure 6, and the spectral transmittance curves for the optical filter in Example 3-4 are shown in Figure 7. Examples 3-1 to 3-3 are examples, while Examples 3-4 to 3-5 are comparative examples.

[0249] [Table 13]

[0250] The optical filters in Examples 3-1 to 3-3 exhibited excellent optical properties, including good transmittance in the visible light region and the near-infrared region around 950 nm, light shielding in the 700-900 nm range, steepness around 900 nm, and oblique incidence characteristics around 900 nm. The optical filters in Examples 3-4 and 3-5 showed good transmittance in the visible light region and the near-infrared region around 950 nm, but exhibited poor light shielding in the 700-900 nm range, steepness around 900 nm, and oblique incidence characteristics around 900 nm.

[0251] 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 invention. This application is based on Japanese Patent Application No. 2020-171326, filed on 9 October 2020, the contents of which are incorporated herein by reference. [Industrial applicability]

[0252] The optical filter of the present invention exhibits excellent transmittance of visible light and specific near-infrared light, has good shielding properties for other near-infrared light, and suppresses the decrease in near-infrared light shielding performance at high incidence angles, thus possessing good near-infrared light shielding characteristics. In recent years, it has become useful in applications such as information acquisition devices like cameras and sensors for transport aircraft, where performance has been steadily increasing. [Explanation of Symbols]

[0253] 1A, 1B, 1C, 1D... Optical filters, 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 (I) having a maximum absorption wavelength of 690 to 900 nm in dichloromethane, and a resin. The optical filter transmits visible light and light in at least a portion of the wavelength range of 900 to 1000 nm, and satisfies all of the following spectral characteristics (i-1), (i-3) to (i-4), and (i-6). (i-1) Maximum transmittance T in the spectral transmittance curve at wavelengths of 700-900 nm and incidence angle of 0 degrees ７００－９００（０ｄｅｇ）ＭＡＸ less than 7% (i-3) The shortest wavelength at which the transmittance is 10% in the spectral transmittance curve at wavelengths of 900-950 nm and an incident angle of 0 degrees is IR10. ９００－９５０（０ｄｅｇ） The shortest wavelength at which the transmittance is 70% is IR70. ９００－９５０（０ｄｅｇ） In that case, IR70 ９００－９５０（０ｄｅｇ） - IR10 ９００－９５０（０ｄｅｇ） less than 20 nm (i-4) The shortest wavelength at which the transmittance is 10% in the spectral transmittance curve at wavelengths of 850-930 nm and an incident angle of 50 degrees is IR10. ８５０－９３０（５０ｄｅｇ） The shortest wavelength at which the transmittance is 70% is IR70. ８５０－９３０（５０ｄｅｇ） In that case, IR70 ８５０－９３０（５０ｄｅｇ） -IR10 ８５０－９３０（５０ｄｅｇ） is 50 nm or less (i-6) Average transmittance T in the spectral transmittance curve at wavelengths of 450-600 nm and an incident angle of 0 degrees ４５０－６００（０ｄｅｇ）ＡＶＥ over 60%

2. The optical filter according to claim 1, wherein the optical filter further satisfies the following spectral characteristics (i-2). (i-2) Maximum transmittance T in the spectral transmittance curve at wavelengths of 700-850 nm and an incident angle of 50 degrees ７００－８５０（５０ｄｅｇ）ＭＡＸ less than 5%

3. The optical filter according to claim 1 or 2, wherein the optical filter further satisfies the following spectral characteristics (i-5). (i-5) The shortest wavelength at which the transmittance is 50% in the spectral transmittance curve at wavelengths of 850 nm or higher and at an incident angle of 0 degrees is IR50. ８５０（０ｄｅｇ） The shortest wavelength at which the transmittance is 50% at an incident angle of 50 degrees is defined as IR50. ８５０（５０ｄｅｇ） In that case, IR50 ８５０（０ｄｅｇ） and IR50 ８５０（５０ｄｅｇ） The absolute value of the difference is 30 nm or less.

4. The optical filter according to any one of claims 1 to 3, wherein the optical filter further satisfies the following spectral characteristics (i-7). (i-7) Average transmittance T in the spectral transmittance curve at wavelengths of 930-950 nm and an incident angle of 0 degrees ９３０－９５０（０ｄｅｇ）ＡＶＥ over 70%

5. In the spectral characteristic (i-6), the average transmittance T ４５０－６００（０ｄｅｇ）ＡＶＥ An optical filter according to any one of claims 1 to 4, wherein the ratio is 75% or more.

6. The optical filter according to any one of claims 1 to 5, wherein the resin film satisfies all of the following spectral characteristics (ii-1) to (ii-5). (ii-1) Average internal transmittance T in the spectral transmittance curve at wavelengths of 450-600 nm ４５０－６００ＡＶＥ over 80% (ii-2) The wavelength IR50 at which the internal transmittance is 50% is in the range of 620 to 660 nm. (ii-3) Average internal transmittance T in the spectral transmittance curve at wavelengths of 700-830 nm ７００－８３０ＡＶＥ less than 5% (ii-4) Maximum internal transmittance T in the spectral transmittance curve at wavelengths of 720-830 nm ７２０－８３０ＭＡＸ less than 10% (ii-5) When the smallest wavelength at which the internal transmittance is 20% in the wavelength range of 850 to 950 nm is defined as IR20, and the smallest wavelength at which the internal transmittance is 80% is defined as IR80, The absolute value of the difference between IR20 and IR80 is 50 nm or less.

7. The optical filter according to any one of claims 1 to 6, wherein the dye (I) satisfies the following characteristic (iii-1) in the spectral internal transmittance curve measured by dissolving the dye (I) in the resin such that the internal transmittance at the maximum absorption wavelength in the resin constituting the resin film is 10%. (iii-1) When the maximum absorption wavelength is D [nm] and the average internal transmittance in the range of 450 to 600 nm is E, then E > 103.5 - (D / 100).

8. The aforementioned dye (I) is A compound (A) having a maximum absorption wavelength in dichloromethane between 690 nm and 735 nm. Compound (B) having a maximum absorption wavelength in dichloromethane between 735 nm and 830 nm. An optical filter according to any one of claims 1 to 7, comprising one or more compounds selected from each of the compounds (C) having a maximum absorption wavelength in dichloromethane between 830 nm and 900 nm.

9. The optical filter according to claim 8, wherein the compound (C) is dissolved in the resin constituting the resin film so that the internal transmittance at the maximum absorption wavelength is 10%, and the spectral internal transmittance curve measured satisfies the following characteristic (iii-2). (iii-2) When the wavelength at which the internal transmittance is 20% is defined as IR20 and the wavelength at which the internal transmittance is 80% is defined as IR80, The absolute value of the difference between IR20 and IR80 is 50 nm or less.

10. The optical filter according to claim 8 or 9, wherein compound (A), compound (B), and compound (C) are selected from either squarylium compounds or cyanine compounds.

11. The optical filter according to any one of claims 1 to 10, wherein the dielectric multilayer film satisfies all of the following spectral characteristics (iv-1) to (iv-6) in the spectral transmittance curve at an incident angle of 0 degrees. (iv-1) Average transmittance T at wavelengths of 450-600 nm ４５０－６００ＡＶＥ over 93% (iv-2) In the wavelength range of 600-800 nm, the wavelength VL50 at which the transmittance is 50% is in the range of 680-750 nm. (iv-3) Average transmittance T at wavelengths of 750-900 nm ７５０－９００ＡＶＥ less than 10% (iv-4) IR50 wavelength, where the transmittance is 50% at wavelengths of 850-950 nm. ８５０－９５０ It is located at 900-930 nm. (iv-5) Average transmittance T at wavelengths of 930-950 nm ９３０－９５０ＡＶＥ over 80% (iv-6) IR50 wavelength, where the transmittance is 50% in the wavelength range of 950-1100 nm. ９５０－１１００ It is located at 1000-1080 nm.

12. The optical filter according to any one of claims 1 to 11, wherein the substrate comprises a support and the resin film, and the resin film is laminated on at least one main surface of the support.

13. The optical filter according to any one of claims 1 to 12, wherein the resin is a polyimide resin.

14. An imaging apparatus comprising an optical filter according to any one of claims 1 to 13.

Images