Filter

Abstract

This invention relates to a filter having a substrate and a dielectric multilayer film laminated on at least one main surface of the substrate as the outermost layer, wherein the substrate comprises a resin film comprising resin and a pigment (A), the pigment (A) being a near-infrared absorbing pigment, and the pigment (A) satisfies specific spectral characteristics in the spectral transmittance curve of a coated film obtained by dissolving the pigment (A) in the resin and coating it onto an alkali glass plate.

Description

[0001] This application is a divisional application of Chinese patent application No. 202180059451.0, filed on July 21, 2021. Technical Field

[0002] This invention relates to a filter that transmits light in the visible wavelength range and blocks light in the near-infrared wavelength range. Background Technology

[0003] In imaging devices using solid-state imaging elements, filters are used to obtain clear images that reproduce tones well, while blocking light in the near-infrared wavelength range (hereinafter referred to as "near-infrared light").

[0004] Examples of such filters include: reflective filters that utilize the interference of light to reflect the light to be blocked, by alternately stacking dielectric films with different refractive indices (dielectric multilayers) on one or both sides of a transparent substrate; and reflective filters. However, filters with dielectric multilayers suffer from several problems because the optical thickness of the multilayer varies with the angle of incidence: changes in the spectral transmittance curve due to the angle of incidence; light leakage due to increased transmittance of near-infrared light at high angles of incidence, where high reflectivity is desirable; and noise caused by near-infrared light reflected from the multilayer. When using such filters, the spectral sensitivity of solid-state imaging elements may be affected by the angle of incidence. Therefore, a filter that blocks near-infrared light without significantly affecting visible light transmittance and without incident angle dependence is needed.

[0005] Here, Patent Document 1 describes a filter having a layer containing near-infrared absorbing pigments in order to reduce incident angle dependence.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: International Publication No. 2019 / 168090 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] However, in the filter described in Patent Document 1, there is room for improvement in terms of transmittance in the visible light region.

[0011] Therefore, the object of the present invention is to provide a filter that, while maintaining good high visible light transmittance, especially blue light transmittance, suppresses the reduction of near-infrared light blocking properties such as light leakage at high incident angles.

[0012] means for solving problems

[0013] The present invention provides a filter having the following configuration.

[0014] [1] A filter having a substrate and a dielectric multilayer film laminated on at least one main surface side of the substrate as the outermost layer, wherein, The substrate comprises a resin film, the resin film comprising resin and pigment (A), wherein pigment (A) is a near-infrared absorbing pigment. For the pigment (A), in the spectral transmittance curve of the coating film obtained by dissolving the pigment (A) in the resin and coating it onto an alkaline glass plate, all of the following spectral characteristics (i-1) to (i-4) are satisfied: (i-1) When the shortest wavelength with a transmittance of 30% in the wavelength range of 600nm to 800nm ​​is set as IR30a, and the longest wavelength with a transmittance of 30% in the wavelength range of 700nm to 1200nm is set as IR30b, The absolute value of the difference between IR30a and IR30b is greater than 170nm; (i-2) When the shortest wavelength with a transmittance of 50% in the wavelength range of 600nm to 800nm ​​is set as IR50a, and the longest wavelength with a transmittance of 50% in the wavelength range of 700nm to 1200nm is set as IR50b, The absolute value of the difference between IR50a and IR50b is greater than 200nm; (i-3) Absorbance A at wavelength 440nm 440 and absorbance A at a wavelength of 700 nm 700 The relationship is A 440 / A 700 ≤0.14; (i-4) Absorbance A at wavelength 490nm 490 and absorbance A at a wavelength of 700 nm 700 The relationship is A 490 / A 700 ≤0.10.

[0015] Invention Effects

[0016] According to the present invention, a filter with high visible light transmittance, high near-infrared light blocking, especially high blue light transmittance, and suppresses the reduction of near-infrared light blocking at high incident angles can be provided. Attached Figure Description

[0017] Figure 1 A cross-sectional view is shown schematically as an example of a filter according to one embodiment.

[0018] Figure 2 A cross-sectional view is shown to schematically illustrate another example of a filter according to one embodiment.

[0019] Figure 3 A cross-sectional view is shown to schematically illustrate another example of a filter according to one embodiment.

[0020] Figure 4 A cross-sectional view is shown to schematically illustrate another example of a filter according to one embodiment.

[0021] Figure 5 The graph shows the spectral transmittance curves of compound 6 in dichloromethane and in cyclic olefin resins.

[0022] Figure 6 A graph showing the spectral transmittance curve of the filter in Example 3-1. Detailed Implementation

[0023] The embodiments of the present invention will be described below.

[0024] In this specification, near-infrared absorbing pigments are sometimes referred to as "NIR pigments" and ultraviolet absorbing pigments are sometimes referred to as "UV pigments".

[0025] In this specification, the compound represented by formula (I) is referred to as compound (I). The same applies to compounds represented by other formulas. Pigments containing compound (I) are also referred to as pigment (I), and the same applies to other pigments. Furthermore, groups represented by formula (I) are also referred to as group (I), and the same applies to groups represented by other formulas.

[0026] In this specification, internal transmittance refers to the transmittance obtained by subtracting the effect of interface reflection from the measured transmittance, expressed by the formula {measured transmittance / (100 - reflectance)} × 100.

[0027] In this specification, the transmittance of the substrate and the transmittance of the resin film containing pigments in the resin are all referred to as "internal transmittance" when they are described as such. On the other hand, the transmittance measured by dissolving the pigment in a solvent such as dichloromethane and the transmittance of the filter having a dielectric multilayer film are measured transmittance.

[0028] In this specification, absorbance is converted from internal transmittance using the formula -log10((internal) transmittance / 100).

[0029] In this specification, for a specific wavelength range, transmittance of 90% or more means that the transmittance is not less than 90% over the entire wavelength range, i.e., the minimum transmittance over that wavelength range is 90% or more. Similarly, for a specific wavelength range, transmittance of 1% or less means that the transmittance is not greater than 1% over the entire wavelength range, i.e., the maximum transmittance over that wavelength range is 1% or less. The same applies to internal transmittance. The average transmittance and average internal transmittance over a specific wavelength range are the arithmetic mean of the transmittance and internal transmittance per 1 nm over that wavelength range.

[0030] In this specification, the "~" sign indicating a numerical range includes both the upper and lower limits.

[0031] <Filter>

[0032] A filter according to one embodiment of the present invention (hereinafter also referred to as "the filter") has a substrate and a dielectric multilayer film laminated on at least one main surface side of the substrate and serving as the outermost layer.

[0033] The configuration example of this filter will be described using the accompanying drawings. Figures 1-4 A cross-sectional view is shown schematically as an example of a filter according to one embodiment.

[0034] Figure 1 The filter 1A shown is an example of having a dielectric multilayer film 30 on one main surface side of the substrate 10. It should be noted that "having a specific layer on the main surface side of the substrate" is not limited to having the layer in contact with the main surface of the substrate, but also includes having other functional layers between the substrate and the layer.

[0035] Figure 2 The filter 1B shown is an example of having a dielectric multilayer film 30 on both main surfaces of the substrate 10.

[0036] Figure 3 The filter 1C shown is an example of a substrate 10 having a support 11 and a resin film 12 laminated on one main side of the support 11. The filter 1C also has a dielectric multilayer film 30 on the resin film 12 and on the main side of the unlaminated resin film 12 on the support 11.

[0037] Figure 4 The filter 1D shown is an example of a substrate 10 having a support 11 and resin films 12 laminated on two main surfaces of the support 11. The filter 1D also has a dielectric multilayer film 30 on each resin film 12.

[0038] <Substrate>

[0039] In the filter of the present invention, the substrate comprises a pigment (A) and a resin. Preferably, the substrate comprises a resin film, the resin film comprising a pigment (A) and a resin.

[0040] <Near-infrared absorbing pigment (A)>

[0041] Pigment (A) is a near-infrared absorbing (NIR) pigment. By incorporating a near-infrared absorbing pigment into the substrate, it is possible to utilize the absorption characteristics of the substrate to suppress the degradation of the spectral characteristics of the dielectric multilayer film at high incident angles, such as the generation of light leakage and noise in the near-infrared region.

[0042] Pigment (A) preferably has a maximum absorption wavelength in the range of 600 nm to 900 nm in dichloromethane.

[0043] Pigment (A) exhibits specific spectral characteristics in the resin used for the substrate. Specifically, a coating film obtained by dissolving pigment (A) in the resin and coating it on an alkali glass plate satisfies all of the following spectral characteristics (i-1) to (i-4).

[0044] (i-1) When the shortest wavelength at which the transmittance in the wavelength range of 600 nm to 800 nm is 30% is designated as IR30a, and the longest wavelength at which the transmittance in the wavelength range of 700 nm to 1200 nm is 30% is designated as IR30b, The absolute value of the difference between IR30a and IR30b is 170 nm or more; (i-2) When the shortest wavelength at which the transmittance in the wavelength range of 600 nm to 800 nm is 50% is designated as IR50a, and the longest wavelength at which the transmittance in the wavelength range of 700 nm to 1200 nm is 50% is designated as IR50b, The absolute value of the difference between IR50a and IR50b is 200 nm or more; (i-3) The absorbance A at a wavelength of 440 nm 440 and the absorbance A at a wavelength of 700 nm 700 are related as A 440 / A 700 ≤ 0.14; (i-4) The absorbance A at a wavelength of 490 nm 490 and the absorbance A at a wavelength of 700 nm 700 are related as A 490 / A 700 ≤ 0.10.

[0045] This filter containing pigment (A) that exhibits the above spectral characteristics (i-1) to (i-4) in the resin is a filter that suppresses the degradation of the near-infrared light blocking property at high incident angles while maintaining good visible light transmittance, particularly blue light transmittance.

[0046] By satisfying spectral characteristics (i-1) and (i-2), it means that near-infrared light can be absorbed over a wide wavelength range. Therefore, light leakage can be effectively prevented in the 750nm–900nm wavelength range, where light leakage is prone to occur due to high incident angles in the dielectric multilayer film. Furthermore, because pigment (A) itself has a wide absorption range in the resin, even without combining multiple NIR pigments, it is possible to effectively block near-infrared light using only pigment (A) while maintaining good transmittance in the visible light region. When multiple NIR pigments are combined, although near-infrared light can be blocked over a wide range, there is a tendency for transmittance in the visible light region to decrease simultaneously; this situation can be avoided by using pigment (A) in this invention.

[0047] The absolute value in the spectral characteristics (i-1) is preferably 190 nm or more, more preferably 210 nm or more, and particularly preferably 230 nm or more. Furthermore, a wider absorption width is preferred; therefore, there is no upper limit, but it is typically 270 nm or less.

[0048] The absolute value in the spectral characteristics (i-2) is preferably 210 nm or more, and more preferably 230 nm or more. In addition, a wider absorption width is preferred, so there is no upper limit, but it is usually 270 nm or less.

[0049] By satisfying spectral characteristics (i-3) and (i-4), it means that the blue light transmittance is excellent.

[0050] The preferred spectral characteristic (i-3) is A. 440 / A 700 ≤0.11, more preferably A 440 / A 700 ≤0.10.

[0051] The preferred spectral characteristic (i-4) is A. 490 / A 700 ≤0.08, more preferably A 490 / A 700 ≤0.07.

[0052] The pigment (A) preferably also exhibits the following spectral characteristics (i-5) in the resin. That is, the above-mentioned coating film containing the pigment (A) and the resin preferably satisfies the following spectral characteristics (i-5).

[0053] (i-5) The product of the content of the pigment (A) in the coating film and the thickness of the coating film is less than 20 (mass %·μm).

[0054] By satisfying the spectral characteristics (i-5), even with a low content of NIR pigment (A), it is possible to absorb near-infrared light over a wide wavelength range. The spectral characteristics (i-5) are preferably 15 (mass%·μm) or less, more preferably 12 (mass%·μm) or less, and more preferably 1 (mass%·μm) or more.

[0055] The pigment (A) preferably also exhibits the following spectral characteristics (i-6) in the resin. That is, the above-mentioned coating film containing the pigment (A) and the resin preferably satisfies the following spectral characteristics (i-6).

[0056] (i-6) Absorbance A at wavelength 570nm 570 and absorbance A at a wavelength of 700 nm 700 The relationship is A 570 / A 700 ≤0.10.

[0057] Satisfying the spectral characteristic (i-6) implies excellent transmittance of green light. The preferred spectral characteristic (i-6) is A. 570 / A 700 ≤0.05, more preferably A 570 / A 700 ≤0.03.

[0058] The pigment (A) preferably also exhibits the following spectral characteristics (i-7) in the resin. That is, the above-mentioned coating film containing the pigment (A) and the resin preferably satisfies the following spectral characteristics (i-7).

[0059] (i-7) Absorbance A at wavelength 630nm 630 and absorbance A at a wavelength of 700 nm 700 The relationship is A 630 / A 700 ≤0.12.

[0060] Satisfying spectral characteristic (i-7) implies excellent transmittance of red light. Spectral characteristic (i-7) is preferably A. 630 / A 700 ≤0.11, more preferably A 630 / A 700 ≤0.08.

[0061] The pigment (A) preferably also exhibits the following spectral characteristics (i-8) in the resin. That is, the above-described coating film containing the pigment (A) and the resin preferably satisfies the following spectral characteristics (i-8).

[0062] (i-8) Average internal transmittance T in the wavelength range of 700 nm to 800 nm in the spectral transmittance curve 700-800 It ranges from 2% to 25%.

[0063] By satisfying the spectral characteristic (i-8), light leakage at high incident angles can be suppressed. The spectral characteristic (i-8) is preferably 2% to 20%, more preferably 2% to 18%.

[0064] Pigment (A) preferably also satisfies the following characteristics (ii-1) and (ii-2).

[0065] The spectral transmittance curve was obtained by dissolving the pigment (A) in dichloromethane in such a manner that the transmittance at the maximum absorption wavelength was 10%. The shortest wavelength with a transmittance of 30% within the wavelength range of 600nm to 900nm will be set as IR30a. (DIC) The longest wavelength with a transmittance of 30% is set to IR30b. (DIC) The shortest wavelength with a transmittance of 50% is set to IR50a. (DIC) The longest wavelength with a transmittance of 50% is set to IR50b. (DIC) , The spectral transmittance curve of the coated film obtained by dissolving the pigment (A) in the resin and coating it onto an alkali glass plate in such a way that the transmittance at the maximum absorption wavelength is 10% is shown in the figure. The shortest wavelength with a transmittance of 30% within the wavelength range of 600nm to 900nm will be set as IR30a. (PO) The longest wavelength with a transmittance of 30% is set to IR30b. (PO) The shortest wavelength with a transmittance of 50% is set to IR50a. (PO) The longest wavelength with a transmittance of 50% is set to IR50b. (PO) , at this time, (ii-1)IR30a (PO) With IR30b (PO) The absolute value of the difference is IR30a (DIC) With IR30b (DIC) More than three times the absolute value of the difference; (ii-2)IR50a (PO) With IR50b (PO) The absolute value of the difference is IR50a (DIC) With IR50b (DIC) The absolute value of the difference is more than 2.8 times.

[0066] By satisfying spectral characteristics (ii-1) and (ii-2), it means that in the near-infrared light absorption band of 600 nm to 900 nm, the absorption width of pigment (A) in the resin is significantly wider than its absorption width in dichloromethane. Here, the resin is the same as the resin contained in the substrate.

[0067] The absolute value in the spectral characteristics (ii-1) is more preferably 3 times or more, and particularly preferably 4 times or more.

[0068] The absolute value in the spectral characteristics (ii-2) is more preferably 3.2 times or more, and particularly preferably 4 times or more.

[0069] As pigment (A), anthocyanin is preferred, and anthocyanin of the external salt type with an anionic group outside the molecule is more preferred. Anthocyanin of the external salt type forms an associated state in the resin, and its near-infrared light absorption band is easily broadened, thus easily satisfying the above-mentioned spectral characteristics (i-1) to (i-8), (ii-1) and (ii-2).

[0070] As anthocyanin, compounds represented by formula (A1) or formula (A2) are preferred.

[0071]

[0072] The symbols in equations (A1) and (A2) are as follows.

[0073] R 101 ~R 109 and R 121 ~R 131 Each can independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 15 carbon atoms that may have substituents, an alkoxy group having 1 to 15 carbon atoms that may have substituents, or an aryl group having 5 to 20 carbon atoms. R 110 ~R 114 and R 132 ~R 136 Each can be independently represented by a hydrogen atom, a halogen atom, or an alkyl group having 1 to 15 carbon atoms, or an alkoxy group having 1 to 15 carbon atoms.

[0074] X - It represents a monovalent anion.

[0075] n1 and n2 are each independently 0 or 1. (In the presence of -(CH2)) n1 - carbon rings and those containing -(CH2) n2 The hydrogen atoms bonded to the carbon ring can be replaced by halogen atoms, alkyl groups having 1 to 15 carbon atoms, or aryl groups having 5 to 20 carbon atoms.

[0076] In equations (A1) and (A2), R 102 ~R 105 R 108 R 109 R 122 ~R 127 R 130 and R131 Each atom is preferably a hydrogen atom, an alkyl group having 1 to 15 carbon atoms or an alkoxy group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms. From the viewpoint of obtaining high visible light transmittance, a hydrogen atom is more preferred.

[0077] In equations (A1) and (A2), R 110 ~R 114 and R 132 ~R 136 Each of the components is preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms, and from the viewpoint of obtaining high visible light transmittance, a hydrogen atom is more preferred.

[0078] R 106 R 107 R 128 and R 129 Each of the following is preferably a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms (which may include straight-chain, cyclic, or branched alkyl groups), and more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. Additionally, R 106 and R 107 Preferably, they are the same group, R 128 and R 129 Preferably, they are the same group.

[0079] R 101 and R 121 Preferably, the carbon atoms are alkyl groups with 1 to 15 carbon atoms or aryl groups with 5 to 20 carbon atoms. From the viewpoint of maintaining the same high visible light transmittance in a transparent resin as in a solution, alkyl groups with 1 to 15 carbon atoms having branches are more preferred.

[0080] As X - Examples include: I - BF4 - PF6 - ClO4 - Or an anion represented by formula (X1) or an anion represented by formula (X2), preferably BF4. - or PF6 - .

[0081]

[0082] In the following description, the pigment (A1) excluding R... 101 ~R 114 The portion outside of this is also called the skeleton (A1). The same applies to other pigments.

[0083] Compounds in formula (A1) with n1 being 1 are shown in formula (A11), and compounds in formula (A1) with n1 being 0 are shown in formula (A12).

[0084]

[0085] In equations (A11) and (A12), R 101 ~R 114 and X - The situation is the same as in equation (A1). R 115 ~R 120 Each can independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 15 carbon atoms that may have substituents, an alkoxy group having 1 to 15 carbon atoms that may have substituents, or an aryl group having 5 to 20 carbon atoms. R 115 ~R 120 Each of the following is preferably a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms (which may include straight-chain, cyclic, or branched alkyl groups), and more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. Additionally, R 115 ~R 120 Preferably, they are the same group.

[0086] Compounds in formula (A2) with n2 = 1 are shown in formula (A21), and compounds in formula (A2) with n2 = 0 are shown in formula (A22).

[0087]

[0088] In equations (A21) and (A22), R 121 ~R 136 and X - The situation is the same as in equation (A2). R 137 ~R 142 Each can independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 15 carbon atoms that may have substituents, an alkoxy group having 1 to 15 carbon atoms that may have substituents, or an aryl group having 5 to 20 carbon atoms. R 137 ~R 142 Each of the following is preferably a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms (which may include straight-chain, cyclic, or branched alkyl groups), and more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. Additionally, R 137 ~R 142 Preferably, they are the same group.

[0089] As compounds represented by formulas (A11), (A12), (A21), and (A22), more specifically, each can be listed as a compound whose atoms or groups bonded to its respective skeleton are those shown in Tables 1 to 4 below. Among all the compounds shown in Tables 1 and 2, R... 101 ~R 109The left and right sides of the formula are the same. Among all the compounds shown in Tables 3 and 4, R... 121 ~R 131 The left and right sides of the formula are the same.

[0090] For R in Table 1 102 ~R 105 R 110 ~R 114 R 115 ~R 120 R in Table 2 102 ~R 105 R 110 ~R 114 R 115 ~R 118 R in Table 3 122 ~R 127 R 132 ~R 136 R 137 ~R 143 R in Table 4 122 ~R 127 R 132 ~R 136 R 137 ~R 140 When all atoms are hydrogen atoms, they are recorded as "H".

[0091] Table 1

[0092] As a pigment (A11), from the viewpoints of synthesis, solubility in resin, heat resistance, and light resistance, (A11-1) to (A11-4), (A11-9) to (A11-12), and (A11-17) to (A11-20) are preferred.

[0093] Table 2

[0094] As pigments (A12), from the viewpoints of synthesis, solubility in resin, heat resistance, and light resistance, (A12-1) to (A12-4), (A12-9) to (A12-12), and (A12-17) to (A12-20) are preferred.

[0095] Table 3

[0096] As the pigment (A21), from the viewpoints of synthesis, solubility in resins, heat resistance, and light resistance, (A21-1) to (A21-4), (A21-9) to (A21-12), and (A21-17) to (A21-20) are preferred.

[0097] Table 4

[0098] As the pigment (A22), from the viewpoints of synthesis, solubility in resins, heat resistance, and light resistance, (A22-1) to (A22-4), (A22-9) to (A22-12), and (A22-17) to (A22-20) are preferred. In particular, from the viewpoints of broad range, maximum absorption wavelength, ability to block light in the range of 700 nm to 850 nm within a wide wavelength band, and ability to maintain high visible light transmittance, (A22-17) to (A22-20) are preferred.

[0099] It should be noted that the pigments (A1) and (A2) can be produced, for example, by the methods described in Dyes and pigments 73(2007) 344 - 352 and J. Heterocyclic chem, 42, 959(2005).

[0100] The resin film may contain either one of the pigments (A1) and (A2) alone, or may contain two or more of the pigments (A1) and (A2) in combination.

[0101] From the viewpoint of satisfying the desired spectral characteristics without degrading the resin properties, the content of the pigment (A) in the resin film is preferably 2 to 25 parts by mass, more preferably 2 to 20 parts by mass, relative to 100 parts by mass of the resin.

[0102] <NIR pigment (B)>

[0103] The substrate in the filter of the present invention may contain, in addition to the pigment (A), a pigment (B) having a maximum absorption wavelength in the range of 600 nm to 900 nm in dichloromethane as a NIR pigment. Thereby, near-infrared light can be blocked more effectively.

[0104] As the pigment (B), it is preferably selected from the group consisting of squaraine pigments, phthalocyanine pigments, naphthalocyanine pigments, dithiol metal complex pigments, azo pigments, polymethine pigments, phthalide pigments, naphthoquinone pigments, anthraquinone pigments, indophenol pigments, pyran pigments, thiopyran pigments, croconic acid pigments, tetrahydrocholine pigments, triphenylmethane pigments, ammonium pigments, and diammonium pigments.

[0105] As pigment (B), it preferably contains a compound selected from squaric acid. At least one of salt pigments, phthalocyanine pigments, and diamine pigments.

[0106] As a squaric acid Salt pigments, preferably compounds represented by the following formula (I).

[0107]

[0108] The symbols in equation (I) are as follows.

[0109] R 24 and R 26 Each of the following can be independently represented: hydrogen atom, halogen atom, hydroxyl group, alkyl group with 1 to 6 carbon atoms or alkoxy group with 1 to 6 carbon atoms, acyloxy group with 1 to 10 carbon atoms, -NR. 27 R 28 (R 27 and R 28 Each independently represents a hydrogen atom, an alkyl group with 1 to 20 carbon atoms, or a -C(=O)-R group. 29 (R 29 (Hydrogen atom, alkyl group with 1 to 20 carbon atoms that may have substituents, or aryl group with 6 to 11 carbon atoms that may have substituents, or aralkyl group with 7 to 18 carbon atoms that may have substituents and may have oxygen atoms between carbon atoms), -NHR 30 or -SO2-R 30 (R 30 Each of the groups consisting of one or more hydrogen atoms may be substituted with halogen atoms, hydroxyl groups, carboxyl groups, sulfonyl groups, or cyano groups, and may contain unsaturated bonds, oxygen atoms, saturated or unsaturated ring structures of 1 to 25 carbon atoms (hydrocarbon groups), or groups represented by the following formula (S) (R). 41 R 42 Independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms. (k is 2 or 3).

[0110]

[0111] R 21 and R 22 R 22 and R 25 and R 21 and R 23 They can connect with each other and together with nitrogen atoms to form 5-membered or 6-membered heterocycles A, B, and C, respectively.

[0112] Regarding R in the case of forming heterocyclic A. 21 and R22 As R 21 and R 22 The bonded divalent group -Q- indicates that the hydrogen atom can be substituted by an alkyl group with 1 to 6 carbon atoms, an aryl group with 6 to 10 carbon atoms, or an alkylene group with 1 to 10 carbon atoms that can have a substituent, or a hydrogen atom can be substituted by an alkyl group with 1 to 6 carbon atoms, an aryl group with 6 to 10 carbon atoms, or an alkylene group with 1 to 10 carbon atoms that can have a substituent.

[0113] Regarding R in the case of forming heterocyclic B. 22 and R 25 And R in the case of forming heterocyclic C 21 and R 23 As R 22 and R 25 The bonded divalent group -X 1 -Y 1 -and R 21 and R 23 The bonded divalent group -X 2 -Y 2 -(The side bonded to nitrogen is X) 1 and X 2 ), X 1 and X 2 Each is a group represented by the following formula (1x) or (2x), Y 1 and Y 2 Each is a group selected from any of the following formulas (1y) to (5y). In X 1 and X 2 When each of the groups is represented by the following formula (2x), Y 1 and Y 2 Each can be a single bond, and in this case, there can be oxygen atoms between carbon atoms.

[0114]

[0115] In formula (1x), each of the four Zs independently represents a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, or -NR. 38 R 39 (R 38 and R 39 Each can independently represent an alkyl group having 1 to 20 hydrogen 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 It represents an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms.

[0116] R 27 R 28 R 29 R 31 ~R 37 R without the formation of heterocycles 21 ~R 23 and R 25 Each can bond with any of the other members to form a 5-membered ring or a 6-membered ring. R 31 and R 36 Direct bonding is possible, R 31 and R 37 They can be bonded directly.

[0117] R without the formation of heterocycles 21 and R 22 Each can independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms that may have substituents, an allyl group having 6 to 11 carbon atoms that may have substituents, or an aryl group having 6 to 11 carbon atoms that may have substituents. R in the case where a heterocycle is not formed. 23 and R 25 Each can be independently represented by a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

[0118] As for compound (I), for example, from the viewpoint of being able to improve visible light transmittance, the compound represented by formula (I-1) is preferred.

[0119]

[0120] The symbols in equation (I-1) are defined in the same way as the same symbols in equation (I), and the preferred methods are also the same.

[0121] In compound (I-1), as X 1 Preferred group (2x) is used as Y. 1 Preferably, a single bond or a group (1y). In this case, as R 31 ~R 36 Preferably, it is an alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom or a methyl group. It should be noted that, as -Y 1 -X 1 Specifically, divalent organic groups represented by formulas (11-1) to (12-3) can be listed.

[0122] -C(CH3)2-CH(CH3)- ……(11-1)

[0123] -C(CH3)2-CH2- ……(11-2)

[0124] -C(CH3)2-CH(C2H5)- ……(11-3)

[0125] -C(CH3)2-C(CH3)(nC3H7)- ……(11-4)

[0126] -C(CH3)2-CH2-CH2-……(12-1)

[0127] -C(CH3)2-CH2-CH(CH3)- ……(12-2)

[0128] -C(CH3)2-CH(CH3)-CH2-……(12-3)

[0129] Furthermore, in compound (I-1), considering the steepness of the change near the boundary between the visible and near-infrared regions in the spectral transmittance curve, R... 21 More preferably, it is a group represented by formula (4-1) or formula (4-2).

[0130]

[0131] In equations (4-1) and (4-2), R 71 ~R 75 Independently representing an alkyl group having 1 to 4 carbon atoms, a hydrogen atom, a halogen atom, or a carbon atom.

[0132] Compound (I) can be manufactured, for example, by the known methods described in U.S. Patent No. 5,543,086, U.S. Patent Application Publication No. 2014 / 0061505, and International Publication No. 2014 / 088063.

[0133] Phthalocyanine pigments include, for example, those described in Japanese Patent No. 5884953 and International Publication No. 2019 / 168090.

[0134] As a diamine pigment, for example, the diamine pigment described in International Publication No. 2014 / 168189 can be cited.

[0135] The resin film may contain only one pigment (B) or a combination of two or more pigments (B).

[0136] The content of pigment (B) in the resin film is preferably 2 to 25 parts by mass relative to 100 parts by mass of resin, and more preferably 2 to 20 parts by mass.

[0137] <Other Pigments>

[0138] The substrate may contain other pigments besides NIR pigments, such as UV pigments.

[0139] Regarding UV pigments, the following can be listed: Zazoles, anthocyanins, naphthalenedicarboximides, diazoles, Azides Examples of UV dyes include azole alkyl groups, naphthalenedicarboxylic acid groups, styryl groups, anthracene groups, cyclic carbonyl groups, and triazole groups. Furthermore, UV dyes can be used alone or in combination with two or more types.

[0140] <Substrate Composition>

[0141] The substrate in this filter can be a single-layer structure or a multi-layer structure. Furthermore, the material used as the substrate can be any transparent material that transmits visible light in the range of 400nm to 700nm; it can be organic or inorganic, without any particular restrictions.

[0142] When the substrate has a single-layer structure, a resin substrate composed of a resin film containing resin and NIR pigment (A) is preferred.

[0143] When the substrate has a multilayer structure, it is preferable to have a composite substrate in which a resin film containing NIR pigment (A) is laminated on at least one main surface of the support. In this case, the support preferably contains a transparent resin or a transparent inorganic material.

[0144] The resin in the resin layer is preferably a transparent resin. From the viewpoint that the NIR pigment (A) forms an associated state and the near-infrared absorption band easily broadens, a polymer composed of an alicyclic compound is preferred as the transparent resin. Examples of such polymers include cycloalkane resins and cycloolefin resins; one or more of these resins may be used alone or in combination.

[0145] When the substrate contains NIR pigment (B) and other pigments, these pigments can be contained in the resin film containing NIR pigment (A), or they can be contained in other resin films. When other resin films are laminated, the transparent resin can be one or more transparent resins selected from polyester resins, acrylic resins, epoxy resins, olefin-thiol resins, polycarbonate resins, polyether resins, polyaryl ester resins, polysulfone resins, polyethersulfone resins, poly(p-phenylene) resins, polyaryl ether phosphine oxide resins, polyamide resins, polyimide resins, polyamide-imide resins, polyolefin resins, cycloolefin resins, polyurethane resins, and polystyrene resins.

[0146] As a transparent inorganic material, glass or crystalline materials are preferred.

[0147] Examples of glasses suitable for use as supports include: absorbing glasses containing copper ions (near-infrared absorbing glasses), such as fluorophosphate glasses or phosphate glasses; soda-lime glass; borosilicate glass; alkali-free glass; and quartz glass. Depending on the purpose, absorbing glasses are preferred; from the viewpoint of absorbing infrared light, phosphate glasses and fluorophosphate glasses are preferred. When it is desired to absorb a large amount of red light (600nm–700nm), alkali glass, alkali-free glass, and quartz glass are preferred. It should be noted that "phosphate glass" also includes silicate phosphate glasses in which a portion of the glass framework is composed of SiO2.

[0148] As a glass, chemically strengthened glass can be used, which is obtained by replacing alkali metal ions with small ionic radii (e.g., Li ions, Na ions) present on the main surface of the glass plate with alkali metal ions with larger ionic radii (e.g., Na ions or K ions for Li ions, and K ions for Na ions) through ion exchange at a temperature below the glass transition temperature.

[0149] Examples of crystalline materials that can be used as supports include: quartz, lithium niobate, sapphire, and other birefringent crystals.

[0150] As a support, inorganic materials are preferred from the perspective of shape stability related to long-term reliability of spectral and mechanical properties, and from the perspective of processability during filter manufacturing. Glass and sapphire are particularly preferred.

[0151] The resin film can be formed by dissolving or dispersing a pigment (A), resin or resin raw material components, and other components to be formulated as needed, in a solvent to prepare a coating solution; applying the coating solution onto a support and drying it; and further curing it as needed. The support can be the support contained in this filter, or it can be a peelable support used only during the formation of the resin film. Furthermore, the solvent can be any dispersion medium that can be stably dispersed or a solvent that can dissolve the resin.

[0152] Furthermore, to improve voids caused by microbubbles, depressions caused by the adhesion of foreign matter, and pinholes during the drying process, the coating liquid may contain surfactants. Additionally, methods such as dip coating, cast coating, or spin coating can be used when applying the coating liquid. The coating liquid is applied to a support and then dried to form a resin film. Furthermore, if the coating liquid contains transparent resin components, further curing treatments such as thermosetting or photocuring are performed.

[0153] Alternatively, the resin film can also be formed into a film shape by extrusion molding. When the substrate is a single-layer structure (resin substrate) consisting of a resin film containing pigment (A), the resin film can be used directly as the substrate. When the substrate is a multilayer structure (composite substrate) having a support and a resin film containing pigment (A) laminated on at least one main surface of the support, the substrate can be manufactured by laminating the film onto the support and integrating it using methods such as hot pressing.

[0154] A filter may contain one layer of resin film or two or more layers of resin film. When there are two or more layers of resin film, each layer may have the same composition or different compositions.

[0155] When the substrate is a multilayer structure (composite substrate) having a support and a resin film containing pigment (A) and resin, the thickness of the resin film is preferably 5 μm or less, more preferably 3 μm or less. Furthermore, the thickness of the resin film is preferably 0.5 μm or more. When the resin film comprises multiple layers, the total thickness of each layer is preferably 0.5 μm to 10 μm.

[0156] In addition, when the substrate is a single-layer structure (resin substrate) composed of a resin film containing pigment (A), the thickness of the resin film is preferably 50 μm to 300 μm.

[0157] The filter of the present invention, by comprising a NIR pigment (A) that satisfies specific spectral characteristics, can effectively block near-infrared light over a wide range, even with a low pigment content. Therefore, it is possible to thin the resin film containing the pigment (A).

[0158] There are no particular restrictions on the shape of the substrate; it can be in the form of a block, plate, or film.

[0159] Furthermore, from the viewpoint of reducing warpage and lowering the height of the filter when forming a dielectric multilayer film, the thickness of the substrate is preferably 300 μm or less. When the substrate is a resin substrate composed of a resin film, the thickness of the substrate is preferably 50 μm to 300 μm. When the substrate is a composite substrate having a support and a resin film, the thickness of the substrate is preferably 100 μm to 300 μm.

[0160] <Dielectric Multilayer Film>

[0161] In this filter, a dielectric multilayer film is stacked on at least one main surface side of the substrate and serves as the outermost layer.

[0162] 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 a NIR reflective layer). The other dielectric multilayer film is preferably designed as an NIR reflective layer, a reflective layer having a reflective region other than the near-infrared region, or an anti-reflective layer.

[0163] A NIR reflective layer is a dielectric multilayer film designed to block light in the near-infrared region. For example, an NIR reflective layer may have wavelength selectivity, transmitting visible light and primarily reflecting light in the near-infrared region, excluding the light-blocking region of the resin film. It should be noted that the reflective region of the NIR reflective layer may also include the light-blocking region of the resin film in the near-infrared region. The NIR reflective layer may also be appropriately designed to block light in wavelength ranges other than the near-infrared region, such as near-ultraviolet light, in addition to its NIR reflective properties.

[0164] The NIR reflective layer is, for example, composed of a dielectric multilayer film obtained by alternating layers of a low-refractive-index dielectric film (low-refractive-index film) and a high-refractive-index dielectric film (high-refractive-index film). The refractive index of the high-refractive-index film is preferably 1.6 or higher, more preferably 2.2 to 2.5. Examples of materials for the high-refractive-index film include Ta₂O₅, TiO₂, and Nb₂O₅. Among these, TiO₂ is preferred from the viewpoints of film formation properties, reproducibility of refractive index, and stability.

[0165] On the other hand, the refractive index of the low-refractive-index film is preferably less than 1.6, more preferably greater than or equal to 1.45 and less than 1.55. Examples of materials that can be used for low-refractive-index films include SiO2 and SiO2. x N y From the perspectives of film-forming reproducibility, stability, and economy, SiO2 is preferred.

[0166] Furthermore, the transmittance of the NIR reflective layer preferably changes steeply within the boundary wavelength range between the transmission region and the light-blocking region. For this purpose, the total number of layers in the dielectric multilayer film constituting the reflective layer is preferably 15 or more, more preferably 25 or more, and even more preferably 30 or more. However, when the total number of layers increases, warping or an increase in film thickness may occur; therefore, the total number of layers is preferably 100 or less, more preferably 75 or less, and even more preferably 60 or less. Additionally, the overall film thickness of the reflective layer is preferably 2 μm to 10 μm.

[0167] If the total number of layers and the film thickness of the dielectric multilayer film are within the above range, the NIR reflective layer meets the requirements for miniaturization and can suppress incident angle dependence while maintaining high productivity. Furthermore, in the formation of the dielectric multilayer film, vacuum film deposition processes such as CVD, sputtering, and vacuum evaporation can be used; wet film deposition processes such as spraying and immersion can also be used.

[0168] A specific spectral characteristic can be imparted using a single NIR reflective layer (a set of dielectric multilayer films), or it can be imparted using two or more NIR reflective layers. When there are two or more NIR reflective layers, each reflective layer can have the same or different configurations. Typically, multiple reflective layers with different reflection bands are used. In the case of two reflective layers, one layer can be a near-infrared reflective layer that blocks short-wavelength light in the near-infrared region, and the other layer can be a near-infrared / near-ultraviolet reflective layer that blocks both long-wavelength light in the near-infrared region and light in the near-ultraviolet region.

[0169] Examples of antireflective layers include: multilayer dielectric films, intermediate refractive index media, and moth-eye structures with gradually changing refractive index. Among these, multilayer dielectric films are preferred from the perspective of optical efficiency and productivity. Like reflective layers, antireflective layers are obtained by alternately stacking dielectric films.

[0170] <Filter>

[0171] The filter of the present invention preferably satisfies all of the following spectral characteristics (iii-1) to (iii-7) by adopting the above-described configuration.

[0172] (iii-1) Average transmittance T in the wavelength range of 440 nm to 490 nm in the spectral transmittance curve with an incident angle of 0 degrees. 440-490(0度)AVE It is over 85%; (iii-2) Average transmittance T in the wavelength range of 440 nm to 490 nm in the spectral transmittance curve with an incident angle of 30 degrees. 440-490(30度)AVE It is over 85%; (iii-3) Average transmittance T in the wavelength range of 500 nm to 570 nm in the spectral transmittance curve with an incident angle of 0 degrees. 500-570(0度)AVE It is over 90%; (iii-4) Average transmittance T in the wavelength range of 500 nm to 570 nm in the spectral transmittance curve at an incident angle of 30 degrees. 500-570(30度)AVE It is over 90%; (iii-5) Maximum transmittance T in the wavelength range of 700 nm to 850 nm in the spectral transmittance curve at an incident angle of 0 degrees. 700-850(0度)MAX Less than 3%; (iii-6) Maximum transmittance T in the wavelength range of 700 nm to 850 nm in the spectral transmittance curve at an incident angle of 30 degrees. 700-850(30度)MAX Less than 1%; (iii-7) The maximum transmittance T in the wavelength range of 700 nm to 850 nm in the spectral transmittance curve at an incident angle of 60 degrees. 700-850(60度)MAXIt is less than 1%.

[0173] By satisfying the spectral characteristics (iii-1) to (iii-4), it is possible to obtain a filter with excellent transmittance in the visible light region, especially blue light, even for light with high incident angles.

[0174] The spectral characteristics (iii-1) and (iii-2) are preferably 86% or higher.

[0175] The spectral characteristics (iii-3) and (iii-4) are preferably 92% or higher.

[0176] By satisfying the spectral characteristics (iii-5) to (iii-7), it is possible to obtain a filter that does not leak light even at high incident angles and has high blocking power for near-infrared light.

[0177] The spectral characteristics (iii-5) are preferably less than 2%.

[0178] The spectral characteristics (iii-6) are preferably below 0.7%.

[0179] The spectral characteristics (iii-7) are preferably below 0.8%.

[0180] This filter can have, for example, constituent elements (layers) that impart absorption by inorganic microparticles that control the transmission and absorption of light within a specific wavelength range. Specific examples of inorganic microparticles include: ITO (indium tin oxide), ATO (antimony-doped tin oxide), cesium tungstate, and lanthanum boride. ITO microparticles and cesium tungstate microparticles have high visible light transmittance and exhibit light absorption over a wide range of infrared wavelengths greater than 1200 nm, thus enabling their use in situations where infrared light blocking is required.

[0181] This filter, for example, can provide an imaging device with excellent color reproduction when used in imaging devices such as digital cameras. An imaging device using this filter includes a solid-state imaging element, an imaging lens, and the filter itself. This filter can be used, for example, by being disposed between the imaging lens and the solid-state imaging element; or by being directly attached to the solid-state imaging element, imaging lens, etc., of the imaging device via an adhesive layer.

[0182] Example

[0183] The invention will now be described in more detail through examples.

[0184] The various spectral characteristics were measured using a UV-Vis spectrophotometer (manufactured by Hitachi High Technology Co., Ltd., model UH-4150).

[0185] It should be noted that the spectral characteristics, unless otherwise specified, are values ​​measured at an incident angle of 0 degrees (the direction perpendicular to the filter).

[0186] The pigments used in each example are described below.

[0187] Compounds 1–9 (cyanin compounds): synthesized according to the synthetic method described on pages 344–352 of Dyes and pigments 73 (2007).

[0188] Compound 10 (squamous acid) Salt compounds: synthesized according to International Publication No. 2014 / 088063.

[0189] Compound 11 (squamous acid) Salt compound): Synthesized according to Japanese Patent Application Publication No. 2017-110209.

[0190]

[0191] <Example 1-1: Spectral characteristics of NIR pigments in resins>

[0192] NIR pigment compound 1 (7.5% by mass) was mixed with polyimide resin (C-3G30G manufactured by Mitsubishi Gas Chemical Co., Ltd.) diluted with an organic solvent (cyclohexanone), and the polyimide solution was thoroughly dissolved with the pigment.

[0193] The obtained pigment solution was spin-coated onto a glass substrate (alkali glass, D263 manufactured by Schott AG), and the organic solvent was removed by thorough heating, thereby producing a pigment-containing resin film (coated film) with a thickness of 1 μm.

[0194] For the obtained thin film, the transmission spectrum at 0 degrees of incident direction in the wavelength range of 350 nm to 1200 nm and the reflection spectrum at 5 degrees of incident direction in the wavelength range of 350 nm to 1200 nm were measured.

[0195] Transmittance is expressed by the internal transmittance as shown in the following formula.

[0196] Internal transmittance (%) = {Measured transmittance} (0度) / (100-reflectivity) (5度) )}×100

[0197] In addition, absorbance is a value obtained by converting internal transmittance using the following formula.

[0198] Absorbance = -log10(internal transmittance / 100)

[0199] <Example 1-2~Example 1-18>

[0200] The pigmented resin films were prepared using the same method as in Example 1-1, except that the contents shown in the table below were replaced with the NIR pigment shown in the table below, the NIR pigments shown in the table below were used instead of NIR pigment compound 1, the following resins were used instead of polyimide resin, and the film thickness was changed to the values ​​shown in the table below.

[0201] Polyester resin: Manufactured by Osaka Gas Chemical Co., Ltd.

[0202] Cycloolefin resin: ARTON F4520 manufactured by JSR Corporation

[0203] The results are shown in the table below.

[0204] It should be noted that Examples 1-10 to 1-14 are examples, while Examples 1-1 to 1-9 and Examples 1-15 to 1-18 are comparative examples.

[0205] IR50 width (nm): The absolute value of the difference between IR50a and IR50b

[0206] IR30 width (nm): The absolute value of the difference between IR30a and IR30b

[0207] Table 5

[0208] Based on the results of Examples 1-10 to 1-14, the external salt-type anthocyanins in alicyclic polymer compounds exhibit a wide range of near-infrared light absorption characteristics while maintaining high blue light transmittance.

[0209] <Comparison of Resin Spectra and Solution Spectra>

[0210] <Example 2-1~Example 2-7: Solution Spectrum>

[0211] The NIR pigments shown in the table below were dissolved in dichloromethane, and the solution spectra in the wavelength range of 350 nm to 1200 nm were measured. The spectral characteristics calculated with a transmittance of 10% for the maximum absorption wavelength are shown in the table below.

[0212] <Examples 2-8 to 2-14: Resin Spectroscopy>

[0213] The spectral characteristics calculated from the transmission and reflection spectra of the thin films manufactured in Examples 1-10 to 1-16, such that the transmittance at the maximum absorption wavelength is 10%, are shown in the table below.

[0214] For the same solution and resin spectra of NIR pigments, the IR50 and IR30 widths were compared.

[0215] In addition, Figure 5 The solution spectra of Compound 6 in Examples 2-4 and the resin spectra in Example 2-11 are recorded. Solid lines represent resin spectra, and dashed lines represent solution spectra.

[0216] IR30 width (DIC) (nm): IR30a (DIC) With IR30b (DIC) The absolute value of the difference

[0217] IR30 width (PO) (nm): IR30a (PO) With IR30b (PO) The absolute value of the difference

[0218] IR50 width (DIC) (nm): IR50a (DIC) With IR50b (DIC) The absolute value of the difference

[0219] IR50 width (PO) (nm): IR50a (PO) With IR50b (PO) The absolute value of the difference

[0220] IR30 width (relative to dichloromethane): IR30 width (PO) Relative to IR30 width (DIC) ratio

[0221] IR50 width (relative to dichloromethane): IR50 width (PO) Relative to IR50 width (DIC) ratio

[0222] Examples 2-1 to 2-7 are reference examples, Examples 2-8 to 2-12 are examples, and Examples 2-13 to 2-14 are comparative examples.

[0223] Table 6

[0224] Table 7

[0225] Based on the above results, in Examples 2-8 to 2-12 where anthocyanins of the external salt type were used as NIR pigments, the widths of IR30 and IR50 were significantly increased in the resin than in the solution.

[0226] That is, the absorption spectrum broadens in the resin.

[0227] <Example 3-1: Spectral Characteristics of a Filter>

[0228] In the polyimide resin (C-3G30G manufactured by Mitsubishi Gas Chemical Co., Ltd.), 5.25% by mass of NIR pigment of compound 11 was added relative to the resin, and cyclohexanone was added as a solvent and allowed to dissolve completely (pigment solution 1).

[0229] In the cyclic olefin resin (ARTON F4520 manufactured by JSR Corporation), 2% by mass of NIR pigment of compound 6 is added relative to the resin, and cyclohexanone is added as a solvent and allowed to dissolve completely (pigment solution 2).

[0230] A UV / IR cutoff multilayer film with a transmission band in the range of 400 nm to 700 nm was deposited on a glass substrate (alkali glass, D263 manufactured by Schott). A pigment solution 1 was spin-coated onto the opposite side of the UV / IR cutoff multilayer film, thereby coating a resin film 1 with a thickness of 1 μm. A pigment solution 2 was then spin-coated onto the resin film 1, thereby coating a resin film 2 with a thickness of 1.6 μm. A dielectric multilayer film (anti-reflective film) composed of SiO2 and TiO2 was formed on the two-layer resin film by vapor deposition, thus fabricating a filter 3-1.

[0231] <Example 3-2>

[0232] The content of compound 11 in the preparation of resin film 1 was changed to 5.5% by mass, and resin film 2 was not coated. Otherwise, filter 3-2 was prepared in the same manner as in Example 3-1.

[0233] For each filter, the transmission spectra at 0°, 30°, and 60° of incident direction within the wavelength range of 350nm to 1200nm were measured using a spectrophotometer. The results are shown in the table below.

[0234] In addition, the spectral transmittance curve of filter 3-1 is shown in Figure 6 middle.

[0235] Example 3-1 is an example, and Example 3-2 is a comparative example.

[0236] Table 8

[0237] Based on the above results, it can be seen that the transmittance of the filter in Example 3-1 in the visible light region of 440nm~490nm and 500nm~570nm is high under the conditions of incident angle of 0 degrees and incident angle of 30 degrees. It has excellent light blocking properties in the infrared region after 700nm. In addition, in the wavelength range of 700nm~850nm, even under the conditions of oblique incident angle of 30 degrees and incident angle of 60 degrees, the maximum transmittance is low, thus reducing light leakage.

[0238] The present invention has been described in detail with reference to specific embodiments, but various changes or modifications may be made without departing from the spirit and scope of the invention, as will be apparent to those skilled in the art. This application is based on Japanese Patent Application No. 2020-128621, filed on July 29, 2020, the contents of which are incorporated herein by reference.

[0239] Industrial practicality

[0240] The filter of the present invention maintains good near-infrared light blocking and visible light transmittance, especially blue light transmittance, while exhibiting excellent near-infrared light blocking characteristics, particularly suppressing the decrease in near-infrared light blocking at high incident angles. It is useful in applications where high-performance information acquisition devices such as conveyor cameras and sensors are increasingly being developed.

[0241] Label Explanation

[0242] 1A, 1B, 1C, 1D... Filters, 10... Substrate, 11... Support, 12... Resin film, 30... Dielectric multilayer film.

Claims

1. A filter having a substrate and a dielectric multilayer film laminated on at least one main surface side of the substrate, wherein, The substrate comprises a resin film, the resin film comprising resin and pigment (A), wherein pigment (A) is a near-infrared absorbing pigment. The resin is a cyclic olefin resin. The pigment (A) comprises at least one of a compound represented by formula (A1) and a compound represented by formula (A2). The filter satisfies all of the following spectral characteristics (iii-1), (iii-3), and (iii-5): (iii-1) the average transmission T in the range of wavelengths from 440 nm to 490 nm in the spectral transmission curve at an angle of incidence of 0 degrees 440-490(0度)AVE is 85% or more; (iii-3) average transmission T in the range of wavelengths 500 nm to 570 nm in the spectral transmittance curve for an angle of incidence of 0 degrees 500-570(0度)AVE is 90% or more; (iii-5) the maximum transmittance T in the range of wavelengths from 700 nm to 850 nm in the spectral transmittance curve for an angle of incidence of 0 degrees 700-850(0度)MAX is 3% or less, The symbols in equations (A1) and (A2) are as follows: R 101 R 106 and R 107 Each of the following can independently represent a hydrogen atom, an alkyl group having 1 to 15 carbon atoms that may have substituents, an alkoxy group having 1 to 15 carbon atoms that may have substituents, or an aryl group having 5 to 20 carbon atoms; R 121 R 128 and R 129 Each of the following can independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 15 carbon atoms that may have substituents, an alkoxy group having 1 to 15 carbon atoms that may have substituents, or an aryl group having 5 to 20 carbon atoms; R 102 ~R 105 R 108 R 109 R 122 ~R 127 R 130 and R 131 Each of the following independently represents a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, an alkoxy group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms; R 110 ~R 114 and R 132 ~R 136 Each of these can be independently represented by a hydrogen atom, a halogen atom, or an alkyl group having 1 to 15 carbon atoms, or an alkoxy group having 1 to 15 carbon atoms. X - Indicates a monovalent anion. n1 and n2 are each independently 0 or 1, in the presence of -(CH2) n1 - carbon rings and those containing -(CH2) n2 The hydrogen atoms bonded to the carbon ring can be replaced by halogen atoms, alkyl groups having 1 to 15 carbon atoms, or aryl groups having 5 to 20 carbon atoms.

2. The filter as described in claim 1, wherein, The filter also satisfies the following spectral characteristics (iii-2), (iii-4), (iii-6), and (iii-7): (iii-2) Average transmittance T in the wavelength range of 440 nm to 490 nm in the spectral transmittance curve with an incident angle of 30 degrees. 440-490(30度)AVE It is over 85%; (iii-4) Average transmittance T in the wavelength range of 500 nm to 570 nm in the spectral transmittance curve at an incident angle of 30 degrees. 500-570(30度)AVE It is over 90%; (iii-6) Maximum transmittance T in the wavelength range of 700 nm to 850 nm in the spectral transmittance curve at an incident angle of 30 degrees. 700-850(30度)MAX Less than 1%; (iii-7) The maximum transmittance T in the wavelength range of 700 nm to 850 nm in the spectral transmittance curve at an incident angle of 60 degrees. 700-850(60度)MAX It is less than 1%.

3. The filter as described in claim 1, wherein, For the pigment (A), in the spectral transmittance curve of the coating film obtained by dissolving the pigment (A) in the resin and coating it onto an alkaline glass plate, all of the following spectral characteristics (i-1) to (i-4) are satisfied: (i-1) When the shortest wavelength with a transmittance of 30% in the wavelength range of 600nm to 800nm ​​is set as IR30a, and the longest wavelength with a transmittance of 30% in the wavelength range of 700nm to 1200nm is set as IR30b, The absolute value of the difference between IR30a and IR30b is greater than 170nm; (i-2) When the shortest wavelength with a transmittance of 50% in the wavelength range of 600nm to 800nm ​​is set as IR50a, and the longest wavelength with a transmittance of 50% in the wavelength range of 700nm to 1200nm is set as IR50b, The absolute value of the difference between IR50a and IR50b is greater than 200nm; (i-3) Absorbance A at wavelength 440nm 440 and absorbance A at a wavelength of 700 nm 700 The relationship is A 440 / A 700 ≤0.14; (i-4) Absorbance A at wavelength 490nm 490 and absorbance A at a wavelength of 700 nm 700 The relationship is A 490 / A 700 ≤0.

10.

4. The filter as described in claim 1, wherein, In the spectral characteristics (iii-3), the average transmittance T in the wavelength range of 500 nm to 570 nm in the spectral transmittance curve at an incident angle of 0 degrees is... 500-570(0度)AVE It is over 92%.

5. The filter as described in claim 2, wherein, In the spectral characteristics (iii-4), the average transmittance T in the wavelength range of 500 nm to 570 nm in the spectral transmittance curve at an incident angle of 30 degrees is... 500-570(30度)AVE It is over 92%.

6. The filter as described in claim 2, wherein, In the spectral characteristics (iii-6), the maximum transmittance T in the wavelength range of 700 nm to 850 nm in the spectral transmittance curve at an incident angle of 30 degrees is... 700-850(30度)MAX It is below 0.7%.

7. The filter as described in claim 2, wherein, In the spectral characteristics (iii-7), the maximum transmittance T in the wavelength range of 700 nm to 850 nm in the spectral transmittance curve at an incident angle of 60 degrees is... 700-850(60度)MAX It is below 0.8%.

8. The filter as claimed in claim 1, wherein, The resin film may be one or two layers.

9. The filter as claimed in claim 1, wherein, The substrate includes a support and the resin film, wherein the thickness of the resin film is less than 5 μm.

10. An imaging device, wherein, The imaging device includes the filter as described in claim 1.

Images