Optical Filters

Abstract

The present invention relates to an optical filter which comprises a base material and a dielectric multilayer film that is superposed, as an outermost layer, on at least one main surface side of the base material, wherein: the base material has a resin film that contains a resin and a dye (I) which has a maximum absorption wavelength of from 690 nm to 900 nm in dichloromethane; the optical filter transmits visible light and at least some light in the wavelength region of from 900 nm to 1,000 nm; and the optical filter satisfies all of specific spectral characteristics (i-1) to (i-6).

Description

[Technical Field]

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

[0002] Imaging devices using solid-state imaging elements are finding wider applications, including surveillance cameras, in-vehicle cameras, and other devices that capture images day and night. These devices need to capture both visible light (color) images and infrared light (black and white) images.

[0003] For this reason, the use of an optical filter, a so-called dual bandpass filter, which has a function of selectively transmitting specific near-infrared light in addition to a near-infrared cut filter function for transmitting the above-mentioned visible light and faithfully reproducing an image based on the visible light, is being considered (Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2016-200771 [Patent Document 2] Japanese Patent Application Publication No. 2019-124946 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the optical filters described in Patent Documents 1 and 2 selectively transmit visible light and near-infrared light of 800 to 900 nm, but do not transmit near-infrared light of 900 nm or longer. In recent years, sensors that detect human eye and body movements have begun to use laser light with a wavelength of around 950 nm, creating a demand for optical filters that can transmit a portion of near-infrared light above 900 nm while blocking other near-infrared light that becomes noise.

[0006] An object of the present invention is to provide an optical filter that has excellent transmittance for visible light and specific near-infrared light, and is capable of blocking other near-infrared light. [Means for solving the problem]

[0007] The present invention provides an optical filter having the following configuration. [1] An optical filter comprising a substrate and a dielectric multilayer film laminated as an outermost layer 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 in dichloromethane at 690 to 900 nm and a resin, the optical filter transmitting visible light and light in at least a part of the wavelength range of 900 to 1000 nm, and satisfying all of the following spectral characteristics (i-1) to (i-6): (i-1) Maximum transmittance T in the spectral transmittance curve at a wavelength of 700 to 900 nm and an incident angle of 0 degrees 700-900(0deg)MAX is 7% or less (i-2) Maximum transmittance T in the spectral transmittance curve at a wavelength of 700 to 850 nm and an incident angle of 50 degrees 700-850(50deg)MAX is less than 5% (i-3) The shortest wavelength at which the transmittance is 10% in the spectral transmittance curve at a wavelength of 900 to 950 nm and an incident angle of 0 degrees is defined as IR10 900-950(0deg) The shortest wavelength at which the transmittance is 70% is IR70 900-950(0deg) When IR70 900-950(0deg) -IR10 900-950(0deg) is 20nm or less (i-4) The shortest wavelength at which the transmittance is 10% in the spectral transmittance curve at a wavelength of 850 to 930 nm and an incident angle of 50 degrees is defined as IR10. 850-930(50deg) The shortest wavelength at which the transmittance is 70% is IR70 850-930(50deg) When IR70 850-930(50deg) -IR10 850-930(50deg) is 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 more and an incident angle of 0 degrees is defined as 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) When IR50 850(0deg) and IR50 850(50deg) The absolute difference is 30 nm or less (i-6) Average transmittance T in the spectral transmittance curve at wavelengths of 450 to 600 nm and an incident angle of 0 degrees 450-600(0deg)AVE More than 60% [Effects of the Invention]

[0008] According to the present invention, an optical filter can be provided which has excellent transmittance for visible light and specific near-infrared light, particularly in the wavelength region of 900 to 1000 nm, and excellent blocking properties for other near-infrared light, particularly in the wavelength region of 700 to 900 nm, and further which suppresses a decrease in blocking properties for near-infrared light at high angles of incidence. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view schematically illustrating an example of an optical filter according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view schematically showing another example of the optical filter according to the embodiment. [Figure 3] FIG. 3 is a cross-sectional view schematically showing another example of the optical filter according to the embodiment. [Figure 4] FIG. 4 is a cross-sectional view schematically showing another example of the optical filter according to the embodiment. [Figure 5] FIG. 5 is a diagram showing the spectral transmittance curve of the dielectric multilayer film of Example 2-1. [Figure 6] FIG. 6 is a diagram showing the spectral transmittance curve of the optical filter of Example 3-1. [Figure 7] FIG. 7 is a diagram showing the spectral transmittance curve of the optical filter of Example 3-4. DETAILED DESCRIPTION OF THE INVENTION

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

[0011] In this specification, the internal transmittance is the transmittance obtained by subtracting the influence of interface reflection from the measured transmittance, as expressed by the formula {measured transmittance / (100-reflectance)}×100. In this specification, the transmittance of a substrate, the transmittance of a resin film including a case where a dye is contained in the resin, and the transmittance spectrum measured by dissolving a dye in a solvent such as dichloromethane are all "internal transmittance" even when they are referred to as "transmittance." On the other hand, the transmittance of an optical filter having a dielectric multilayer film is an actually measured transmittance.

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

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

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

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

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

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

[0018] The optical filter of the present invention transmits visible light and light in at least a part 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 a wavelength of 700 to 900 nm and an incident angle of 0 degrees 700-900(0deg)MAX is 7% or less (i-2) Maximum transmittance T in the spectral transmittance curve at a wavelength of 700 to 850 nm and an incident angle of 50 degrees 700-850(50deg)MAX is less than 5% (i-3) The shortest wavelength at which the transmittance is 10% in the spectral transmittance curve at a wavelength of 900 to 950 nm and an incident angle of 0 degrees is defined as IR10 900-950(0deg) The shortest wavelength at which the transmittance is 70% is IR70 900-950(0deg) When IR70 900-950(0deg) -IR10 900-950(0deg) is 20nm or less (i-4) The shortest wavelength at which the transmittance is 10% in the spectral transmittance curve at a wavelength of 850 to 930 nm and an incident angle of 50 degrees is defined as IR10. 850-930(50deg) The shortest wavelength at which the transmittance is 70% is IR70 850-930(50deg) When IR70 850-930(50deg) -IR10 850-930(50deg) is 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 more and an incident angle of 0 degrees is defined as 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) When IR50 850(0deg) and IR50 850(50deg) The absolute difference is 30 nm or less (i-6) Average transmittance T in the spectral transmittance curve at wavelengths of 450 to 600 nm and an incident angle of 0 degrees 450-600(0deg)AVE More than 60%

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

[0020] Satisfying the spectral characteristic (i-1) means that the shielding property is excellent in the range of 700 to 900 nm. 700-900(0deg)MAX is preferably 6.5% or less, more preferably 6% or less.

[0021] By satisfying the spectral characteristic (i-2), it means that the blocking properties in the wavelength range of 700 to 850 nm are excellent even at high incident angles. 700-850(50deg)MAX is preferably 4.5% or less, more preferably 4% or less.

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

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

[0024] Satisfying the spectral characteristic (i-5) means that there is little shift even at high angles of incidence in the NIR absorption band at wavelengths of 850 nm or more, and that color reproducibility is excellent. The spectral characteristic (i-5) is preferably 29 nm or less, and more preferably 28 nm or less.

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

[0026] It is preferable that the optical filter further satisfies the following spectral characteristic (i-7). (i-7) Average transmittance T in the spectral transmittance curve at wavelengths of 930 to 950 nm and an incident angle of 0 degrees 930-950(0deg)AVE Over 70%

[0027] Satisfying the spectral characteristic (i-7) means that the glass has excellent transmittance in the near-infrared light region with wavelengths of 930 to 950 nm. 930-950(0deg)AVE is preferably 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) described below and a resin.

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

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

[0031] By satisfying the spectral characteristic (ii-2), it is possible to compensate for the oblique incidence shift of the dielectric multilayer film, which has excellent transmittance in the red band and excellent light-shielding properties in the near-infrared light 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] By satisfying the spectral characteristic (ii-3), it means that the film has excellent shielding properties in the near-infrared light region with wavelengths of 700 to 830 nm. 700-830AVE is preferably 4% or less, more preferably 3% or less.

[0033] By satisfying the spectral characteristic (ii-4), it means excellent shielding property in the near-infrared light region with a wavelength of 720 to 830 nm. T 720-830MAX is 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 at 690 to 900 nm in dichloromethane. 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 is 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. By the dye (I) satisfying 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 the range of 690 to 900 nm in dichloromethane. From the viewpoint of efficiently blocking light between the visible light and the specific near-infrared light region transmitted by this filter, it is preferable that the dye contain three or more compounds having a maximum absorption wavelength in the range of 690 to 900 nm in dichloromethane, and it is particularly preferable that the dye contain one or more compounds selected from each of the compounds (A) to (C) having the following properties: 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 at a wavelength of 735 nm or more and less than 830 nm Compound (C) having a maximum absorption wavelength in dichloromethane at a wavelength of 830 nm or more and less than 900 nm

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

[0040] As the NIR dye (I), a squarylium dye or a cyanine dye is preferred from the viewpoints of transparency in the visible light region, solubility in resins, and durability.

[0041] <Squarylium dyes> The squarylium dye is preferably a compound represented by the following formula (I) or (II). When two or more identical symbols are present in a squarylium dye compound, the symbols may be the same or different. The same applies to cyanine dyes.

[0042] <Squarylium Compounds (I)>

[0043] [ka]

[0044] However, the symbols in the above formula are as follows: R 24 and R 26 are each independently a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group or an alkoxy group having 1 to 20 carbon atoms, an acyloxy group having 1 to 10 carbon atoms, an aryl group having 6 to 11 carbon atoms, an araryl group having 7 to 18 carbon atoms which may have a substituent and which may have an oxygen atom between the carbon atoms, -NR 27 R 28 (R 27 and R 28 are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or -C(=O)-R 29 (R 29 represents a hydrogen atom, a halogen atom, a hydroxyl group, a hydrocarbon group having 1 to 25 carbon atoms which may have a substituent and which may contain an unsaturated bond between carbon atoms, an oxygen atom, or a saturated or unsaturated ring structure), -NHR 30 , or -SO2-R 30 (R 30 represents a hydrocarbon group having 1 to 25 carbon atoms, each of which may have one or more hydrogen atoms substituted with a halogen atom, a hydroxyl group, a carboxyl group, a sulfo group, or a cyano group, and which may contain an unsaturated bond, an oxygen atom, or a saturated or unsaturated ring structure between carbon atoms), or a group represented by the following formula (S): 41 , R 42 are independently a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 10 carbon atoms. k is 2 or 3.

[0045] [ka]

[0046] R 21 and R 22 , R 22 and R 25 , and R21 and R 23 may be linked to each other to form, together with the nitrogen atom, 5- or 6-membered heterocycles A, B, and C, respectively. R when heterocycle A is formed 21 and R 22 represents a divalent group -Q- to which they are bonded, which is an alkylene group or alkyleneoxy group in which a hydrogen atom may be substituted with an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an acyloxy group having 1 to 10 carbon atoms which may have a substituent. R when heterocycle B is formed 22 and R 25 and R when heterocycle C is formed. 21 and R 23 are the divalent groups -X 1 -Y 1 - and -X 2 -Y 2 -(The side that is bonded to nitrogen is X 1 and X 2 ) as X 1 and X 2 are groups represented by the following formula (1x) or (2x), and Y 1 and Y 2 are each a group selected from the following formulas (1y) to (5y): 1 and X 2 are groups represented by the following formula (2x), Y 1 and Y 2 may each be a single bond, in which case there may be an oxygen atom between the carbon atoms.

[0047] [ka]

[0048] In formula (1x), four Z's each independently represent a hydrogen atom, a hydroxyl group, an alkyl group or an alkoxy group having 1 to 6 carbon atoms, or -NR 38 R 39 (R 38 and R 39R each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. 31 ~R 36 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms, R 37 represents an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms. R 27 , R 28 , R 29 , R 31 ~R 37 , R when not forming a heterocycle 21 ~R 23 , and R 25 may be bonded to any other of these to form a 5- or 6-membered ring. 31 and R 36 , R 31 and R 37 may be directly bonded. When a heterocyclic ring is not formed, R 21 , R 22 , R 23 and R 25 each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group or 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 araryl group having 7 to 18 carbon atoms which may have a substituent and which may have an oxygen atom between the carbon atoms.

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

[0050] [ka]

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

[0052] In compound (I-1), X 1 As the group (2x), the group (2x) is preferred. 1 is preferably a single bond or a group (1y). 31 ~R 36 is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom or a methyl group. 1 -X 1 Specific examples of - include divalent organic groups represented by formulas (11-1) to (12-3).

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

[0055] [ka]

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

[0057] In compound (I-1), R 24Ha-NR 27 R 28 -NR is preferred. 27 R 28 From the viewpoint of solubility in resins and coating solvents, -NH-C(=O)-R 29 or -NH-SO2-R 30 is preferred.

[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 are each independently preferably a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 6 carbon atoms, and more preferably a hydrogen atom.

[0061] R 29 The substituent is preferably an alkyl group having 1 to 20 carbon atoms which may have a substituent, an aryl group having 6 to 10 carbon atoms which may have a substituent, or an araryl group having 7 to 18 carbon atoms which may have a substituent and which may have an oxygen atom between the carbon atoms. Examples of the substituent include a hydroxyl group, a carboxy group, a sulfo group, a cyano group, an alkyl group having 1 to 6 carbon atoms, a fluoroalkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and an acyloxy group having 1 to 6 carbon atoms.

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

[0063] R 29As the alkyl group, a hydrocarbon group having 5 to 25 carbon atoms and at least one branch, 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 an unsaturated bond, an oxygen atom, or a saturated or unsaturated ring structure between carbon atoms, can also be preferably used.

[0064] More specifically, compound (I-11) includes the compounds shown in the following table: In the compounds shown in the following table, the symbols on the left and right of the squarylium skeleton have the same meaning.

[0065] [Table 1]

[0066] Of these, compounds (I-11-11) to (I-11-15) and (I-11-26) to (I-11-30) are preferred as compound (I-11) from the viewpoints of transparency in the visible light region and solubility in resins.

[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 are each independently preferably a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 6 carbon atoms, and more preferably a hydrogen atom.

[0070] R 30 From the viewpoint of light resistance, R is preferably an alkyl group or alkoxy group having 1 to 12 carbon atoms, which may be branched, or a hydrocarbon group having 6 to 16 carbon atoms and an unsaturated ring structure. Examples of the unsaturated ring structure include benzene, toluene, xylene, furan, and benzofuran.30 are more preferably independently an alkyl group or alkoxy group having 1 to 12 carbon atoms, which may have a branch. 30 In each group represented by the formula (I), some or all of the hydrogen atoms may be substituted with halogen atoms, particularly fluorine atoms.

[0071] More specifically, compound (I-12) includes the compounds shown in the following table: In the compounds shown in the following table, the symbols on the left and right of the squarylium skeleton have the same meaning.

[0072] [Table 2]

[0073] Of these, compounds (I-12-11) to (I-12-15) and (I-12-26) to (I-12-30) are preferred as compound (I-12) from the viewpoints of transparency in the visible light region and solubility in resins.

[0074] <Squarylium Compounds (II)>

[0075] [ka]

[0076] However, the symbols in the above formula are as follows: Each ring Z is independently a 5- 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 bonded to each other to form heterocycles A1, B1, and C1 together with the nitrogen atom, respectively, and in this case, the hydrogen atoms of heterocycles A1, B1, and C1 may be substituted. 1and R 2 R each independently represents a hydrogen atom, a halogen atom, or a hydrocarbon group which may contain an unsaturated bond between carbon atoms, a heteroatom, or a saturated or unsaturated ring structure and which may have a substituent. 4 and R when no heterocycle is formed. 3 each independently represents a hydrogen atom, a halogen atom, or an alkyl or alkoxy group which may contain a heteroatom between carbon atoms and which may have a substituent.

[0077] Examples of compound (II) include compounds represented by any of formulas (II-1) to (II-3). From the viewpoints of solubility in resins and visible light transmittance in resins, 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 a substituent, and R 3 ~R 6 each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms which may have a substituent.

[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 a substituent, and R 7 and R 8 each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms which may have a substituent.

[0081] R in Compound (II-1) and Compound (II-2) 1 and R2 are each independently preferably an alkyl group having 1 to 15 carbon atoms, more preferably an alkyl group having 7 to 15 carbon atoms, from the viewpoints of solubility in resin, visible light transmittance, etc., and R 1 and R 2 More preferably, at least one of R is a branched alkyl group having 7 to 15 carbon atoms, 1 and R 2 It is particularly preferable that both of the groups are alkyl groups having a branched chain and having 8 to 15 carbon atoms.

[0082] R in compound (II-3) 1 From the viewpoints of solubility in a transparent resin, visible light transmittance, etc., each of the groups is preferably an alkyl group having 1 to 15 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms, and particularly preferably an ethyl group or an isopropyl group.

[0083] R 4 From the viewpoints of visible light transmittance and ease of synthesis, is preferably a hydrogen atom or a halogen atom, and particularly preferably a hydrogen atom. R 7 and R 8 are each preferably a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms which may be substituted with a halogen atom, and more preferably a hydrogen atom, a halogen atom, or a methyl group.

[0084] R 9 ~R 12 are preferably independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms which may be substituted with a halogen atom. -CR 9 R 10 -CR 11 R 12 Examples of - include 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, examples of compound (II-3) include the compounds shown in the following table: In the compounds shown in the following table, the symbols on the left and right of the squarylium skeleton have the same meaning.

[0086] [Table 3]

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

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

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

[0090] [ka]

[0091] However, the symbols in the above formula are as follows: R 101 ~R 109 and R 121 ~R 131 R each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 15 carbon atoms which may have a substituent, or an aryl group having 5 to 20 carbon atoms. 110 ~R 114 and R 132 ~R 136each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 15 carbon atoms. X - indicates a monovalent anion. n1 and n2 are 0 or 1. -(CH2) n1 Carbocycles containing - and -(CH2) n2 A hydrogen atom bonded to a carbocyclic ring containing - may be substituted with a halogen atom, an alkyl group having 1 to 15 carbon atoms which may have a substituent, or an aryl group having 5 to 20 carbon atoms.

[0092] In the above, the alkyl group (including the alkyl group of an alkoxy group) may be linear or may have a branched structure or a saturated ring structure. The aryl group refers to a group that bonds via a carbon atom constituting an aromatic ring of an aromatic compound, such as a benzene ring, naphthalene ring, biphenyl, furan ring, thiophene ring, or pyrrole ring. Examples of the substituent in the alkyl group or alkoxy group having 1 to 15 carbon atoms or the aryl group having 5 to 20 carbon atoms that may have a substituent include a halogen atom and an alkoxy group having 1 to 10 carbon atoms.

[0093] In formula (III) and formula (IV), R 101 and R 121 is preferably an alkyl group having 1 to 15 carbon atoms or an aryl group having 5 to 20 carbon atoms, and more preferably a branched alkyl group having 1 to 15 carbon atoms from the viewpoint of maintaining high visible light transmittance in the resin.

[0094] In formula (III) and formula (IV), R 102 ~R 105 , R 108 , R 109 , R 122 ~R 127 , R 130 and R 131 are each independently preferably a hydrogen atom, an alkyl or alkoxy group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms, and more preferably a hydrogen atom from the viewpoint of obtaining a high visible light transmittance.

[0095] In formula (III) and formula (IV), R 110 ~R 114 and R 132 ~R 136 are each independently preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms, and more preferably a hydrogen atom from the viewpoint of obtaining a high visible light transmittance.

[0096] R 106 , R 107 , R 128 and R 129 are each independently preferably a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms (which may include a linear, cyclic, or branched alkyl group), more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. 106 and R 107 , R 128 and R 129 are preferably the same group.

[0097] X - As for I - , BF4 - , PF6 - , ClO4 - , anions represented by formula (X1) and (X2), etc., and preferably BF4 - , or PF6 - is.

[0098] [ka]

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

[0100] In formula (III), a compound in which n1 is 1 is shown in formula (III-1) below, and a compound in which n1 is 0 is shown in formula (III-2) below.

[0101] [ka]

[0102] In formula (III-1) and formula (III-2), R 101 ~R 114 and X - is the same as in formula (III). 115 ~R 120 R each independently represents a hydrogen atom, a halogen atom, an alkyl group or alkoxy group having 1 to 15 carbon atoms which may have a substituent, or an aryl group having 5 to 20 carbon atoms. 115 ~R 120 are each independently preferably a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms (which may include a linear, cyclic, or branched alkyl group), more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. 115 ~R 120 are preferably the same group.

[0103] In formula (IV), a compound in which n2 is 1 is shown in formula (IV-1) below, and a compound in which n2 is 0 is shown in formula (IV-2) below.

[0104] [ka]

[0105] In formula (IV-1) and formula (IV-2), R 121 ~R 136 and X - is the same as in formula (IV). 137 ~R 142 R each independently represents a hydrogen atom, a halogen atom, an alkyl group or alkoxy group having 1 to 15 carbon atoms which may have a substituent, or an aryl group having 5 to 20 carbon atoms. 137 ~R 142 are each independently preferably a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms (which may include a linear, cyclic, or branched alkyl group), more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. 137 ~R142 are preferably the same group.

[0106] More specifically, the compounds represented by formula (III-1), formula (III-2), formula (IV-1), and formula (IV-2) each include compounds in which the atom or group bonded to each skeleton is an atom or group shown in the table below. In all of the compounds shown in the table below, R 101 ~R 109 are the same on both sides of the formula. In all compounds shown in the table below, R 121 ~R 131 is identical on both sides of the equation.

[0107] R in the table below 110 -R 114 and R in the table below 132 -R 136 indicates the atom or group bonded to the central benzene ring of each formula, and when all five are hydrogen atoms, it is written as "H". 110 -R 114 If one of the groups is a substituent and the other is a hydrogen atom, only the combination of the symbol and the substituent is described. For example, "R 112 -C(CH3)3" is R 112 is -C(CH3)3, and the rest are hydrogen atoms. 132 -R 136 The same is true for .

[0108] R in Table 4 115 -R 120 and R in Table 6 137 -R 142 represents an atom or group bonded to the central cyclohexane ring in formula (III-1) or formula (IV-1), and when all six are hydrogen atoms, it is written as "H". 115 -R 120 When one of the groups is a substituent and the other is a hydrogen atom, only the combination of the symbol and the substituent is shown. 137 -R 142 The same is true for .

[0109] R in Table 5 115 -R 118 and R in Table 7 137 -R 140 represents an atom or group bonded to the central cyclopentane ring in formula (III-2) or formula (IV-2), and when all four are hydrogen atoms, it is written as "H". 115 -R 118 When one of the groups is a substituent and the other is a hydrogen atom, only the combination of the symbol and the substituent is shown. 137 -R 140 The same is true for .

[0110] In the table below, X - Although no compound exhibits X - is BF4 - or PF6 - is.

[0111] [Table 4]

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

[0113] [Table 5]

[0114] Among these, the dyes (III-2-1) to (III-2-5) are preferred as the dye (III-2) from the viewpoints of transparency in the visible light region and solubility in resins.

[0115] [Table 6]

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

[0117] [Table 7]

[0118] Among these, the dyes (IV-2) are preferably the dyes (IV-2-1) to (IV-2-5) in terms of transparency in the visible light range and solubility in resin.

[0119] As described above, dye (III) and dye (IV) have different skeletons, which results in different wavelength regions of absorption maxima. For dye (III), the maximum absorption wavelength is in the wavelength region of approximately 760 to 830 nm, depending on the types and combinations of atoms and groups bonded to the skeleton. For dye (IV), the maximum absorption wavelength is in the wavelength region of approximately 800 to 900 nm, depending on the types and combinations of atoms and groups bonded to the skeleton.

[0120] Furthermore, in dye (III), the maximum absorption wavelength differs depending on whether n1 of the skeleton is 1 or 0. Although it depends on the types and combinations of atoms and groups bonded to the skeleton, when n1 is 1, the maximum absorption wavelength is in the wavelength range of approximately 760 to 800 nm, and when n1 is 0, the maximum absorption wavelength is in the wavelength range of approximately 800 to 830 nm.

[0121] Similarly, in dye (IV), the maximum absorption wavelength differs depending on whether n2 is 1 or 0. Although it depends on the types and combinations of atoms and groups bonded to skeleton (IV-1), when n2 is 1, the maximum absorption wavelength is in the wavelength range of approximately 800 to 830 nm, and when n2 is 0, the maximum absorption wavelength is in the wavelength range of approximately 830 to 900 nm.

[0122] Dye (III) and dye (IV) can be produced by the method described in, for example, Dyes and Pigments 73 (2007) 344-352 or J. Heterocyclic Chem, 42, 959 (2005).

[0123] <Cyanine Compounds (V)>

[0124] [ka]

[0125] Here, the symbols in formula (V) are as follows: R 1 ~R 7 are each independently a hydrogen atom, a halogen atom, a sulfo group, a hydroxyl group, a cyano group, a nitro group, a carboxy group, a phosphate group, an alkyl group having 1 to 10 carbon atoms which may have a substituent, an alkoxy group having 1 to 10 carbon atoms which may have a substituent, or an acyloxy group having 1 to 10 carbon atoms which may have a substituent. In formula (V), R 1 ~R 7 may be the same or different on the left and right sides of the formula, but it is preferable that they are all the same.

[0126] Examples of the substituent in the alkyl group, alkoxy group or acyloxy group having 1 to 10 carbon atoms which may have a substituent include a halogen atom and an alkoxy group having 1 to 10 carbon atoms.

[0127] Here, in this specification, unless otherwise specified, the alkyl group may be linear, branched, cyclic, or a combination of these structures. The same applies to the alkyl group possessed by the alkoxy group. Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms, with fluorine atoms and chlorine atoms being preferred.

[0128] R 1From the viewpoint of ease of synthesis, each of 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, and particularly preferably a hydrogen atom.

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

[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 secondary or tertiary branched alkyl group having 10 or less carbon atoms, and further preferably a tertiary butyl group, an isopropyl group, or an isobutyl group.

[0131] R 2 ~R 5 , R 6 ~R 7 or two adjacent groups may be linked to each other to form a ring having 5 to 8 members. The ring may be aliphatic or aromatic.

[0132] Formula (V) optionally has Z. Z is a 5-membered or 6-membered ring. When Z is present, it is preferable in terms of durability. The hydrogen atom bonded to the carbon atom constituting Z may be substituted with an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms.

[0133] In this specification, unless otherwise specified, an aryl group refers to a group bonded via a carbon atom constituting an aromatic ring contained in an aromatic compound, such as a benzene ring, a naphthalene ring, a biphenyl, a furan ring, a thiophene ring, or a pyrrole ring.

[0134] X - indicates a monovalent anion. X - PF6 - , [Rf-SO2] - , [N(Rf-SO2)2] - , or BF4 - 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. When the anion has such a structure, a dye compound (V) having 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 -OC(=O)-), or a ureido bond (-NH-C(=O)-NH-), and R 10 represents 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 -Y is a single bond 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] More specifically, in formula (V), the atoms or groups bonded to each skeleton are shown in the following table. In all of the compounds shown in the following table, R 1 ~R 7 are all identical on both sides of the equation.

[0138] [Table 8]

[0139] Of these, compounds (V-1) to (V-4) are preferred as compound (V) from the viewpoints of transparency in the visible light range and solubility in resin.

[0140] Regarding the production method of compound (V), R in compound (V) 1 ~R 5 , R 7 is a hydrogen atom, and X - BF4 - The following description will be given using a method for producing compound (V1) represented by the formula: Figure imgf000012_0001, but the method for producing compound (V1) is not limited thereto. The route to obtain compound (V1) is shown below.

[0141] [ka]

[0142] (1) Salicylaldehyde (a) and R 6 The compound (c) is obtained by reacting the alkyne compound (b) having a group. (2) Compound (c) is reacted with 4-dimethylaminopyridine to obtain compound (d). (3) Compound (d) is reacted with methylmagnesium bromide and tetrafluoroboric acid to obtain compound (e). (4) Compound (e) is reacted with R 8 The compound (V1) is obtained by reacting the compound (V2) with aldehyde dianilide hydrochloride (f) having a group.

[0143] X - PF6 - In this case, hexafluorophosphoric acid is used instead of tetrafluoroboric acid in step (3) above, and X - [Rf-SO2] - In this case, by using Rf-SO3H instead of tetrafluoroboric acid in the above step (3), X - [N(Rf-SO2)2] -In this case, they 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 formula (VI) are as follows:

[0147] X - is a monovalent anion species. Examples of monovalent anion species include PF6 - , BF4 - , N(SO2CF3)2 - , CF3SO3 - , ReO4 - , ClO4 - , Cl - , Br - , I - , BPh4 - , B(C6F5)4 - , CF3COO - , C(SO2CF3)3 - , p-toluenesulfonyl anion, and the like. Here, Ph means a phenyl group.

[0148] Among these, from the viewpoint of enhancing the light resistance of compound (VI), X - PF6 - , BF4 - , N(SO2CF3)2 - It is preferable to select from among:

[0149] m is 0 or 1, and is preferably 1. R1 is a monovalent anionic group when m is 0. Examples of the monovalent anionic group include anionic groups represented by any one of the following formulas (C1) to (C6).

[0150] [ka]

[0151] In formulas (C1) to (C6), R 201 ~R 214 each 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 a substituent. Examples of the substituent include a halogen atom or an alkoxy group having 1 to 10 carbon atoms.

[0152] When m is 1, R1 is a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms which may have a substituent, an araryl group having 7 to 13 carbon atoms which may have a substituent, or -NR9R 10 is.

[0153] Examples of the halogen atom in R1 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0154] The number of carbon atoms in the alkyl group for R1 is preferably 1 to 10, more preferably 1 to 6. Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an isobutyl group, and a tert-butyl group. Among these, a methyl group is particularly preferred from the viewpoint of synthesis.

[0155] Examples of the aryl group having 6 to 12 carbon atoms in R1 include groups that bond via a carbon atom constituting an aromatic ring in an aromatic compound (e.g., a benzene ring, a naphthalene ring, a biphenyl, a furan ring, a thiophene ring, a pyrrole ring, etc.). Among these, a phenyl group is preferred from the viewpoint of not impairing the transmittance in the blue wavelength region.

[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 which may contain a saturated ring structure and which are substituted with one or more aryl groups. Among these, araryl groups having a phenyl group are preferred from the viewpoint of not impairing the transmittance in the blue region.

[0157] Examples of the substituent that R1 may have include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, a hydroxyl group, a carboxy group, a sulfo group, a cyano group, an amino group, an N-substituted amino group, a nitro group, an alkoxycarbonyl group, a carbamoyl group, an N-substituted carbamoyl group, and an imide group.

[0158] R9, R 10 are each independently an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms which may have a substituent, or a carbonyl group having 1 to 12 carbon atoms which may have a substituent.

[0159] R9, R 10 Specific examples of alkyl groups and aryl groups in R and R 10 Specific examples of the substituent that may be possessed by are the same as those of R1.

[0160] R9, R 10 Examples of the carbonyl group having 1 to 12 carbon atoms in the formula include an acetyl group, an ethanoyl group, a propanoyl group, a benzoyl group, a trifluoroacetyl group, and a pentafluoroethanoyl group.

[0161] Among these, from the viewpoint of not impairing the transmittance in the blue wavelength region and from the viewpoint of synthesis, 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.

[0162] R2 to R7 are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms which may have a substituent, or an araryl group having 7 to 13 carbon atoms which may have a substituent. Adjacent two of R2 to R7 may be linked to each other to form a 5- to 8-membered ring.

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

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

[0165] Among these, R2 to R5 are preferably a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, more preferably a hydrogen atom, from the viewpoint of not impairing the transmittance in the blue wavelength range and from the viewpoint of synthesis.

[0166] Furthermore, from the viewpoint of increasing the transmittance in the blue wavelength region, R6 and R7 are preferably an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms which may have a substituent, more preferably a secondary alkyl group having 1 to 12 carbon atoms, a tertiary alkyl group having 1 to 12 carbon atoms, or a phenyl group having substituents at the 2- and 6-positions, and even more preferably an isopropyl group, a tert-butyl group, a sec-butyl group, a 2,6-dimethylphenyl group, a 2,4,6-trimethylphenyl group, a 2,6-diisopropylphenyl group, or a 2,4,6-triisopropylphenyl group.

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

[0168] [ka]

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

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

[0171] R 11 , R 12 are each 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 number of carbon atoms in the alkyl group in the formula is preferably 1 to 8, more preferably 1 to 5. Examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, an isopropyl group, and a tert-butyl group.

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

[0174] R 11 , R 12 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 perpendicular to the π-conjugated plane. This breaks the π-conjugation between the phenyl group and dye A, and the phenyl group exerts an induced electron-withdrawing effect. This electron-withdrawing effect allows compound (VI-1) to have absorption in the near-infrared region of 720 to 760 nm and to increase the transmittance in the blue region.

[0175] Among these, R 11 , R 12 From the viewpoint of synthesis, is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms, and further preferably a methyl group, an ethyl group, or an isopropyl group.

[0176] R 13 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 13 The number of carbon atoms in the alkyl group in the formula is preferably 1 to 8, more preferably 1 to 5. Examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, an isopropyl group, and a tert-butyl group.

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

[0179] Among these, R 13 From the viewpoint of synthesis, is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms, and further preferably a methyl group, an ethyl group, or an isopropyl group.

[0180] Also, R 13 is other than a hydrogen atom, R 13 is R 11 , R 12 From the viewpoint of synthesis, it is preferable that the above formula is the same as the formula:

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

[0182] [Table 9]

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

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

[0185] [ka]

[0186] <Step 1> The starting material (g), trimethylsilylacetylene, tetrakis(triphenylphosphine)palladium(0), copper iodide, and diethylamine are added to a recovery flask. After degassing the flask, the atmosphere is replaced with nitrogen and the mixture is heated and stirred. After the reaction is complete, the solvent is removed by distillation under reduced pressure, water is added, and the mixture is extracted with dichloromethane. The dichloromethane is removed by distillation under reduced pressure, and the mixture is purified to obtain intermediate (h).

[0187] <Step 2> Add intermediate (h) and methanol to a recovery flask and cool on ice. Add potassium carbonate and stir under a nitrogen stream. After the reaction is complete, the reaction mixture is filtered to remove the potassium carbonate, and the filtrate is evaporated under reduced pressure. Add water to the resulting liquid and extract with dichloromethane. Evaporate the dichloromethane under reduced pressure and purify to obtain intermediate (i).

[0188] <Step 3> Add intermediate (i) and tetrahydrofuran to a recovery 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 by distillation under reduced pressure and wash the resulting solid to obtain intermediate (j).

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

[0190] <Step 5> Intermediate (k), p-toluenesulfonic acid monohydrate, methanol, and toluene are added to a recovery flask and stirred. The solvent is then removed under reduced pressure, and methanol and concentrated hydrochloric acid are added and stirred. After the reaction is complete, the reaction solution is cooled on ice, water is added to stop the reaction, and the solution is extracted with dichloromethane. Dichloromethane is removed under reduced pressure, and toluene and trifluoromethanesulfonic acid are added and stirred. After the reaction is complete, the reaction solution is cooled on ice, water is added to stop the reaction, and the toluene layer is extracted. Toluene is removed under reduced pressure, purification is carried out, and the resulting powder is washed to obtain intermediate (l).

[0191] <Step 6> Intermediate (l) and tetrahydrofuran are added to a recovery flask and stirred. Methylmagnesium bromide is then added and heated and stirred under a nitrogen stream. After the reaction is complete, the reaction solution is poured little by little into a 10% by weight acidic aqueous solution and stirred to stop the reaction. This solution is extracted with dichloromethane, and the dichloromethane layer is washed with water, after which the dichloromethane is distilled off under reduced pressure. The resulting powder is washed to obtain intermediate (m).

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

[0193] <Step 7> Add intermediate (m), malonaldehyde dianilide hydrochloride, sodium acetate, acetic acid, and acetic anhydride to a recovery flask and heat with stirring under a nitrogen stream. After the reaction is complete, the reaction solution is cooled on ice, water is added, and the reaction solution is filtered to recover the powder. After purifying the powder, the resulting solid is washed to obtain compound (VI-1-a).

[0194] The content of the 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 the resin. When two or more compounds are combined, the above content is the total of the respective compounds.

[0195] <Other dyes> The resin film may contain other dyes, such as UV dyes, in addition to the NIR dye. Specific examples of UV dyes include oxazole-based, merocyanine-based, cyanine-based, naphthalimide-based, oxadiazole-based, oxazine-based, oxazolidine-based, naphthalic acid-based, styryl-based, anthracene-based, cyclic carbonyl-based, triazole-based dyes, etc. One type of UV dye may be used alone, or two or more types may be used in combination.

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

[0197] The resin is not limited as long as it is a transparent resin, and one or more transparent resins selected from polyester resin, acrylic resin, epoxy resin, enethiol resin, polycarbonate resin, polyether resin, polyarylate resin, polysulfone resin, polyethersulfone resin, polyparaphenylene resin, polyarylene ether phosphine oxide resin, polyamide resin, polyimide resin, polyamideimide resin, polyolefin resin, cyclic olefin resin, polyurethane resin, polystyrene resin, etc. These resins may be used alone or in combination of two or more. From the viewpoint of the spectral characteristics, glass transition temperature (Tg) and adhesiveness of the resin film, one or more resins selected from polyimide resin, polycarbonate resin, polyester resin and acrylic resin are preferred.

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

[0199] As the transparent inorganic material, glass or crystalline material is preferred. Examples of glass that can be used for the support include absorption-type glass (near-infrared absorbing glass) containing copper ions in fluorophosphate glass or phosphate glass, soda-lime glass, borosilicate glass, alkali-free glass, and quartz glass.

[0200] The glass may be chemically strengthened glass obtained by ion exchange at a temperature equal to or lower than the glass transition point to exchange alkali metal ions (e.g., Li ions, Na ions) having a small ionic radius present on the main surface of the glass plate with alkali ions having a larger ionic radius (e.g., Na ions or K ions for Li ions, and K ions for Na ions).

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

[0202] As the support, inorganic materials are preferred, and glass and sapphire are particularly preferred, from the viewpoint of shape stability related to long-term reliability of optical properties, mechanical properties, etc., and ease of handling during filter production.

[0203] The resin film can be formed by dissolving or dispersing the dye (I), the resin or resin raw material components, and other components blended as needed in a solvent to prepare a coating solution, applying the coating solution to a support, drying, and optionally curing. The support may be the support included in the filter, or a peelable support used only when forming the resin film. The solvent may be any dispersion medium or solvent capable of stably dispersing the dye (I) or dissolving the dye (I).

[0204] The coating liquid may also contain a surfactant to prevent voids caused by microbubbles, depressions caused by the adhesion of foreign matter, and repellency during the drying process. For example, the coating liquid can be applied by dip coating, cast coating, or spin coating. After the coating liquid is applied to a support, a resin film is formed by drying. When the coating liquid contains raw materials for a transparent resin, it is further subjected to a curing treatment such as thermal curing or photocuring.

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

[0206] The optical filter may have one resin film layer or two or more resin films. When the optical filter has two or more resin films, the layers may have the same or different configurations.

[0207] When the substrate has a single layer structure (resin substrate) made of a resin film containing dye (I), the thickness of the resin film is preferably 20 to 150 μm. When the substrate has 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. When the optical filter has two or more resin films, the total thickness of the resin films is preferably within the above range.

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

[0209] The filter may also include other components, such as a component (layer) that provides absorption by inorganic fine particles that control the transmission and absorption of light in a specific wavelength range. Specific examples of inorganic fine particles include ITO (indium tin oxide), ATO (antimony-doped tin oxide), cesium tungstate, and lanthanum boride. ITO fine particles and cesium tungstate fine particles have high transmittance for visible light and absorb light over a wide range of infrared wavelengths exceeding 1200 nm, and therefore can be used when blocking such infrared light is required.

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

[0211] In the present 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 in the wavelength range of 450 to 600 nm 450-600AVE Over 93% (iv-2) In the wavelength range of 600 to 800 nm, the wavelength VL50 at which the transmittance is 50% is in the range of 680 to 750 nm (iv-3) Average transmittance T in the wavelength range of 750 to 900 nm 750-900AVE is less than 10% (iv-4) IR50, the wavelength at which the transmittance is 50% in the wavelength range of 850 to 950 nm 850-950 is in the range of 900 to 930 nm (iv-5) Average transmittance T at wavelengths of 930 to 950 nm 930-950AVE Over 80% (iv-6) IR50, the wavelength at which the transmittance is 50% in the wavelength range of 950 to 1100 nm 950-1100 is in the 1000~1080nm range

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

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

[0214] By satisfying the spectral characteristic (iv-3), it means that the film has excellent light-blocking properties in the near-infrared light region with wavelengths of 750 to 900 nm. 750-900AVE is preferably 8.5% or less, more preferably 7% or less.

[0215] By satisfying the spectral characteristic (iv-4), it means that the film has excellent light-blocking properties in the near-infrared light region with wavelengths of 750 to 900 nm and excellent transmittance in the near-infrared light region with wavelengths of 930 to 950 nm. 850-950is preferably in the range of 905 to 930 nm, more preferably 910 to 930 nm.

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

[0217] By satisfying the spectral characteristic (iv-6), it means that the film has excellent transmittance in the near-infrared light region with wavelengths of 930 to 950 nm and excellent light-blocking properties in the near-infrared light region with wavelengths of 1080 nm and above. 950-1100 is preferably in the range of 1005 to 1080 nm, more preferably 1010 to 1075 nm.

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

[0219] The NIR reflective layer is a dielectric multilayer film designed to block light in the near-infrared region. The NIR reflective layer, for example, transmits visible light and specific near-infrared light, and has wavelength selectivity that mainly reflects light other than the light-shielding region of the resin film that is the absorption layer and the specific near-infrared light. The reflective region of the NIR reflective layer may include a light-shielding region in the near-infrared region of the resin film. The NIR reflective layer is not limited to NIR reflection characteristics, and may be appropriately designed to further block light in wavelength regions other than the near-infrared region, for example, the near-ultraviolet region.

[0220] The NIR reflective layer is composed of, for example, a dielectric multilayer film in which dielectric films with low refractive index (low refractive index film) and dielectric films with high refractive index (high refractive index film) are alternately laminated. The high refractive index film preferably has a refractive index of 1.6 or more, more preferably 2.2 to 2.5. Examples of materials for the high refractive index film include Ta2O5, TiO2, and Nb2O5. Of these, TiO2 is preferred in terms of film formability, reproducibility in refractive index, etc., and stability.

[0221] On the other hand, the low refractive index film preferably has a refractive index of less than 1.6, more preferably 1.45 or more and less than 1.55. Examples of materials for the low refractive index film include SiO2, SiO x N y In terms of reproducibility, stability, economy, etc. in film formation, SiO2 is preferred.

[0222] In order for the NIR reflective layer to transmit visible light and specific near-infrared light, it is possible to combine several types of dielectric multilayer films with different spectral characteristics when transmitting and selecting the desired wavelength band. For example, it can be adjusted by the material constituting the film, the thickness of each layer, and the number of layers.

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

[0224] The dielectric multilayer film can be formed by vacuum film-forming processes such as CVD, sputtering, and vacuum deposition, or wet film-forming processes such as spraying and dipping.

[0225] The NIR reflective layer may be a single layer (a group of dielectric multilayer films) that provides predetermined optical characteristics, or two layers that provide predetermined optical characteristics. When there are two or more layers, the reflective layers may have the same or different configurations. When there are two or more reflective layers, they are usually composed of multiple reflective layers with different reflection bands. When two reflective layers are provided, one may be a near-infrared reflective layer that blocks light in the short wavelength band of the near-infrared region, and the other may be a near-infrared / near-ultraviolet reflective layer that blocks light in both the long wavelength band of the near-infrared region and the near-ultraviolet region.

[0226] Examples of antireflection layers include dielectric multilayer films, intermediate refractive index media, and moth-eye structures in which the refractive index changes gradually. Among these, dielectric multilayer films are preferred from the viewpoints of optical efficiency and productivity. Antireflection layers are obtained by alternately laminating dielectric multilayer films, similar to reflective layers.

[0227] When used in an imaging device such as a digital still camera, this filter can provide an imaging device with excellent color reproducibility. An imaging device using this filter includes a solid-state imaging element, an imaging lens, and this filter. This filter can be used, for example, by being placed between the imaging lens and the solid-state imaging element, or by being directly attached to the solid-state imaging element, imaging lens, etc. of the imaging device via an adhesive layer. [Example]

[0228] Next, the present invention will be explained more specifically with reference to examples. Each optical property was measured using an ultraviolet-visible spectrophotometer (UH-4150, manufactured by Hitachi High-Technologies Corporation). Unless the angle of incidence is specifically stated, the spectral characteristics are values ​​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 (squarylium dye): synthesized based on US Pat. No. 5,543,086. Compound 2 (squarylium dye): Synthesized based on US Pat. No. 5,543,086. Compound 3 (squarylium dye): synthesized based on the specifications of U.S. Patent Application Publication No. 2014 / 0061505 and WO 2014 / 088063. Compound 4 (cyanine dye): Synthesized according to Synthesis Example 1 described below. Compound 5 (squarylium dye): Synthesized based on WO 2017 / 135359. Compound 6 (cyanine dye): Synthesized according to Synthesis Example 2 described below. Compounds 7, 8, and 9 (cyanine dyes): Synthesized based on Dyes and pigments 73 (2007) 344-352. Compound 10: Synthesized based on Japanese Patent No. 4081149. Compound 11: Synthesized based on WO 2020 / 129909. Compound 12: Synthesized based on JP 2014-25016 A.

[0230] [ka]

[0231] [ka]

[0232] [ka]

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

[0234] [ka]

[0235] <Step 1> A 1000 mL recovery flask was charged with 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). The flask was degassed, replaced with nitrogen, and heated and stirred at 50°C for 6 hours. After completion of the reaction, the solvent was removed by distillation under reduced pressure, water was added, and the mixture was extracted with dichloromethane. After dichloromethane was removed by distillation under reduced pressure, the product was purified by flash column chromatography (hexane) to obtain 90.1 g (quantity) of intermediate ia. <Step 2> Intermediate ia (90.1 g, 416.4 mmol) and methanol (600 mL) were placed in a 1 L recovery flask and cooled on ice. Potassium carbonate (167.9 g, 1214.8 mmol) was added and stirred at room temperature for 1 hour under a nitrogen stream. 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 evaporated under reduced pressure. Water was added to the resulting orange-yellow liquid, which was then extracted with dichloromethane. After the dichloromethane was evaporated under reduced pressure, the product was purified by flash column chromatography (hexane) to obtain 58.5 g (quantity) of intermediate ib. <Step 3> Intermediate ib (22.0 g, 152.6 mmol) and tetrahydrofuran (125 mL) were added to a 1000 mL recovery flask and stirred at -78 °C under a nitrogen stream. n-Butyllithium (1.6 mol / L in hexane) (100 mL) was added using a dropping funnel and stirred at -78 °C for 1 hour. Ethyl formate (5.7 g, 76.3 mmol) dissolved in 20 mL of tetrahydrofuran was then added using a dropping funnel and stirred at -78 °C for 5 hours and then at 0 °C for 1.5 hours. After completion of the reaction, water was added to quench the reaction, and the mixture was extracted with dichloromethane. Dichloromethane was evaporated under reduced pressure, and the resulting ochre solid was washed with hexane to yield 13.4 g (56%) of intermediate ic. <Step 4> Intermediate ic (25.9 g, 83.7 mmol), dichloromethane (500 mL), and manganese oxide (36.4 g, 418.7 mmol) were added to a 1000 mL recovery flask and stirred at room temperature for 1 hour under a nitrogen stream. After completion of the reaction, the reaction solution was filtered to remove the manganese oxide, and the filtrate was evaporated under reduced pressure. The resulting yellow powder was washed with hexane to obtain 23.6 g (92%) of intermediate id. <Step 5> 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 to a 1000 mL recovery flask and stirred at 110 °C for 8 hours. The solvent was then removed under reduced pressure, and methanol (280 mL) and concentrated hydrochloric acid (70 mL) were added. The mixture was stirred at 70 °C overnight. After completion of the reaction, the reaction solution was ice-cooled, water was added to quench the reaction, and the mixture was extracted with dichloromethane. After dichloromethane was removed under reduced pressure, 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 completion of the reaction, the reaction solution was ice-cooled, water was added to quench the reaction, and the toluene layer was extracted. After toluene was distilled off under reduced pressure, the residue was purified by flash column chromatography (hexane / dichloromethane) to obtain a pink powder, which was washed with hexane to obtain 15.5 g (67%) of intermediate ie. <Step 6> Intermediate ie (6.0 g, 18.0 mmol) and tetrahydrofuran (75 mL) were added to a 500 mL recovery flask and stirred at 0 °C. Methylmagnesium bromide (13% tetrahydrofuran solution) (49.7 g, 54.1 mmol) was added and heated and stirred at 70 °C for 1 hour under a nitrogen stream. After completion of the reaction, the reaction solution was poured in portions into 10% aqueous hexafluorophosphoric acid solution (350 mL) at 0 °C and stirred at 0 °C for 10 minutes to quench the reaction. This solution was extracted with dichloromethane, and the dichloromethane layer was washed with water. The dichloromethane was then distilled off under reduced pressure. The resulting yellow powder was washed with hexane to yield 8.2 g (95%) of intermediate if. <Step 7> 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 to a 200 mL recovery flask and stirred at 80 °C for 45 minutes under a nitrogen stream. After completion of the reaction, the reaction solution was cooled on 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 1:1 hexane:ethyl acetate 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 (13 g, 160 mmol) and tetrahydrofuran (40 mL) were placed in a 1 L recovery flask and cooled to -78°C with stirring. Normal butyllithium (1.6 M in normal hexane, 100 mL) was added dropwise and stirred at -78°C for 1 hour. Salicylaldehyde (10 g, 82 mmol) dissolved in tetrahydrofuran (80 mL) was then added and stirred at room temperature for 3 hours. After completion of the reaction, the mixture was quenched with saturated aqueous ammonium chloride and extracted with ethyl acetate. After removing the solvent, manganese dioxide (35 g, 400 mmol) and acetone (80 mL) were added and stirred at room temperature for 16 hours. After completion of the reaction, the mixture was filtered, the solvent was removed from the filtrate, and the mixture was purified by column chromatography to obtain 6.1 g (37%) of 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 completion of the reaction, 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, it was 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 completion of the reaction, ice water was added for quenching, 60% aqueous solution of hexafluorophosphoric acid in hexane (150 mL) was added, and it was 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), malonaldialdehyde 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 it was stirred at 80 °C for 2 hours. After completion of the reaction, water was added, the precipitated solid was collected by filtration, 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 it was 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 the spectral reflectance curve of this resin-coated glass plate, a spectral internal transmittance curve was calculated and normalized so that the transmittance at the maximum absorption wavelength would be 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> A polyimide resin (C-3G30G manufactured by Mitsubishi Gas Chemical Company, Ltd.) was dissolved in an organic solvent (cyclohexanone:γ-butyrolactone=1:1 mass ratio) at a concentration of 8.5 mass %. Each compound was added to the polyimide resin solution prepared above so that the content (parts by mass) of each compound was as shown in the table below relative to 100 parts by mass of the resin, and the mixture was 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 thickness of 3 μm. The spectral characteristics are shown in the table below. Examples 1-1 to 1-6 are reference examples.

[0242] [Table 11]

[0243] Examples 1-1 to 1-3 have a wide absorption band in the near-infrared light region and high visible light transmittance. Examples 1-4 have a narrow absorption band in the near-infrared region. Example 1-5 has a slightly narrow absorption width in the near-infrared light region. Example 1-6 has a wide absorption range in the near-infrared light region, but a low visible light transmittance. This is thought to be because the addition of compound (B) was increased to widen the absorption range, resulting in absorption in the visible light region as well.

[0244] <Example 2-1: Spectral characteristics of dielectric multilayer film> The reflective layer was designed to consist of a 69-layer dielectric multilayer film 1 and a 76-layer dielectric multilayer film 2, each of which was made by alternately stacking TiO2 and SiO2 films. The combined spectral characteristics of dielectric multilayer film 1 and dielectric multilayer film 2 are shown in the table below. FIG. 5 shows the spectral transmittance curve of the combined dielectric multilayer film 1 and dielectric multilayer film 2. Note that Example 2-1 is a reference example.

[0245] [Table 12]

[0246] <Example 3-1: Optical characteristics of optical filters> An optical filter was obtained by stacking the dielectric multilayer film 2 prepared in Example 2-1, a glass substrate (alkali glass, D263 manufactured by Schott), the resin film of 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 characteristics of optical filters> An optical filter was obtained in the same manner as in Example 3-1, except that the resin film was changed to one shown in the table below.

[0248] The spectral characteristics are shown in the table below. FIG. 6 shows the spectral transmittance curve of the optical filter of Example 3-1, and FIG. 7 shows the spectral transmittance curve of the optical filter of Example 3-4. Examples 3-1 to 3-3 are working examples, and Examples 3-4 to 3-5 are comparative examples.

[0249] [Table 13]

[0250] The optical filters of Examples 3-1 to 3-3 exhibited excellent optical properties, including excellent transmittance in the visible light region and near-infrared light region around 950 nm, excellent light blocking properties from 700 to 900 nm, excellent steepness around 900 nm, and excellent oblique incidence properties around 900 nm. The optical filters of Examples 3-4 and 3-5 had good transmittance in the visible light region and the near-infrared light region around 950 nm, but had poor light blocking properties from 700 to 900 nm, poor steepness around 900 nm, and poor 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 present invention. This application is based on a Japanese patent application (Patent Application No. 2020-171326) filed on October 9, 2020, the contents of which are incorporated herein by reference. [Industrial Applicability]

[0252] The optical filter of the present invention has excellent transmittance for visible light and specific near-infrared light, has blocking properties for other near-infrared light, and has good near-infrared light blocking properties in which the decrease in blocking properties for near-infrared light at high incident angles is suppressed. The optical filter is useful for applications in information acquisition devices, such as cameras and sensors for transport aircraft, which have been increasingly sophisticated in recent years. [Explanation of symbols]

[0253] 1A, 1B, 1C, 1D...optical filter, 10...substrate, 11...support, 12...resin film, 30...dielectric multilayer film

Claims

1. An optical filter comprising a substrate and a dielectric multilayer film laminated as an outermost layer 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 in dichloromethane at 690 to 900 nm and a resin; The optical filter transmits visible light and light in at least a part 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 a wavelength of 700 to 900 nm and an incident angle of 0 degrees ７００－９００（０ｄｅｇ）ＭＡＸ is less than 7% (i-2) Maximum transmittance T in the spectral transmittance curve at a wavelength of 700 to 850 nm and an incident angle of 50 degrees ７００－８５０（５０ｄｅｇ）ＭＡＸ is less than 5% (i-3) The shortest wavelength at which the transmittance is 10% in the spectral transmittance curve at a wavelength of 900 to 950 nm and an incident angle of 0 degrees is defined as IR10 ９００－９５０（０ｄｅｇ） The shortest wavelength at which the transmittance is 70% is defined as IR70. ９００－９５０（０ｄｅｇ） When IR70 ９００－９５０（０ｄｅｇ） -IR10 ９００－９５０（０ｄｅｇ） is 20 nm or less (i-4) The shortest wavelength at which the transmittance is 10% in the spectral transmittance curve at a wavelength of 850 to 930 nm and an incident angle of 50 degrees is defined as IR10 ８５０－９３０（５０ｄｅｇ） The shortest wavelength at which the transmittance is 70% is defined as IR70. ８５０－９３０（５０ｄｅｇ） When IR70 ８５０－９３０（５０ｄｅｇ） -IR10 ８５０－９３０（５０ｄｅｇ） is 50 nm or less (i-5) The shortest wavelength at which the transmittance is 50% in the spectral transmittance curve at a wavelength of 850 nm or more and an incident angle of 0 degrees is defined as 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） When IR50 ８５０（０ｄｅｇ） and IR50 ８５０（５０ｄｅｇ） The absolute value of the difference is 30 nm or less (i-6) Average transmittance T in the spectral transmittance curve at a wavelength of 450 to 600 nm and an incident angle of 0 degrees ４５０－６００（０ｄｅｇ）ＡＶＥ More than 60%

2. 2. The optical filter according to claim 1, wherein the optical filter further satisfies the following spectral characteristic (i-7): (i-7) Average transmittance T in the spectral transmittance curve at a wavelength of 930 to 950 nm and an incident angle of 0 degrees ９３０－９５０（０ｄｅｇ）ＡＶＥ More than 70%

3. In the spectral characteristic (i-6), the average transmittance T ４５０－６００（０ｄｅｇ）ＡＶＥ 3. The optical filter according to claim 1, wherein the .lambda.

4. 4. The optical filter according to claim 1, 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 to 600 nm ４５０－６００ＡＶＥ More than 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 to 830 nm ７００－８３０ＡＶＥ is less than 5% (ii-4) Maximum internal transmittance T in the spectral transmittance curve at wavelengths of 720 to 830 nm ７２０－８３０ＭＡＸ is less than 10% (ii-5) In the wavelength range of 850 to 950 nm, when the minimum wavelength at which the internal transmittance is 20% is defined as IR20 and the minimum 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

5. The optical filter according to any one of claims 1 to 4, wherein the dye (I) satisfies the following characteristic (iii-1) in a spectral internal transmittance curve measured by dissolving the dye (I) in a resin constituting the resin film so that the internal transmittance at the maximum absorption wavelength in the resin 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, E>103.5-(D / 100)

6. The dye (I) is a compound (A) having a maximum absorption wavelength in dichloromethane at a wavelength of 690 nm or more and less than 735 nm; a compound (B) having a maximum absorption wavelength in dichloromethane at a wavelength of 735 nm or more and less than 830 nm; 6. The optical filter according to claim 1, comprising at least one compound selected from the group consisting of compounds (C) having a maximum absorption wavelength in dichloromethane at a wavelength of 830 nm or more and less than 900 nm.

7. The optical filter according to claim 6, wherein the compound (C) satisfies the following characteristic (iii-2) in a spectral internal transmittance curve measured by dissolving the compound (C) in a resin constituting the resin film so that the internal transmittance at the maximum absorption wavelength is 10%. (iii-2) On the longer wavelength side than the maximum absorption wavelength, 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

8. 8. The optical filter according to claim 6, wherein the compound (A), the compound (B), and the compound (C) are selected from the group consisting of squarylium compounds and cyanine compounds.

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

10. 10. The optical filter according to claim 1, wherein the substrate includes a support and the resin film, and the resin film is laminated on at least one main surface of the support.

11. 11. The optical filter according to claim 1, wherein the resin is a polyimide resin.

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