Light-absorbing composition, production method for light-absorbing composition, light absorption film, optical filter, and manufacturing method for optical filter

Abstract

A light-absorbing composition according to the present invention contains: an ultraviolet ray-absorbing compound having a hydroxy group and a carbonyl group in a molecule; metal components; polyvinyl butyral; and isocyanate. At least some of the metal components are bonded to organic oxy groups.

Description

Light-absorbing composition, method for producing light-absorbing composition, light-absorbing film, optical filter, and method for producing optical filter

[0001] The present invention relates to a light-absorbing composition, a light-absorbing film, and an optical filter.

[0002] In imaging devices using solid-state imaging elements such as CCDs (Charge Coupled Devices) or CMOSs ​​(Complementary Metal Oxide Semiconductors), various optical filters are placed in front of the solid-state imaging elements to obtain images with good color reproducibility. Generally, solid-state imaging elements have spectral sensitivity over a wider wavelength range than the human visual sensitivity corresponding to the visible light range. Therefore, a known technique involves placing an optical filter in front of the solid-state imaging element to block part of infrared or ultraviolet light in order to bring the spectral sensitivity of the solid-state imaging element in an imaging device closer to the human visual sensitivity.

[0003] Conventionally, such optical filters have typically utilized light reflection by a dielectric multilayer film to block infrared or ultraviolet light. However, in recent years, optical filters equipped with a film containing a light-absorbing agent have been attracting attention. Because the transmittance characteristics of optical filters equipped with a film containing a light-absorbing agent are less affected by the angle of incidence, they can produce good images with little change in color even when light is incident on the optical filter at an angle in an imaging device. Furthermore, light-absorbing optical filters that do not use a light-reflecting film can suppress the occurrence of ghosts and flares caused by multiple reflections by the light-reflecting film, making it easier to obtain good images in backlit conditions or when photographing night scenes. Additionally, optical filters equipped with a film containing a light-absorbing agent are advantageous in terms of miniaturizing and thinning imaging devices.

[0004] As such a light absorber, a light absorber formed from phosphonic acid and copper ions is known. For example, Patent Document 1 describes an optical filter having a light absorbing layer containing a light absorber formed from phosphonic acid having a phenyl group or a halogenated phenyl group (phenyl-based phosphonic acid) and copper ions.

[0005] Furthermore, Patent Document 2 describes an optical filter having a UV-IR absorbing layer capable of absorbing infrared and ultraviolet rays. The UV-IR absorbing layer contains a UV-IR absorber formed from phosphonic acid and copper ions. To ensure that the optical filter has predetermined optical properties, the UV-IR absorbing composition contains, for example, a phenyl-based phosphonic acid and a phosphonic acid having an alkyl group or a halogenated alkyl group (an alkyl-based phosphonic acid).

[0006] Furthermore, Patent Document 3 describes an ophthalmic device including a vertical violet light cutoff filter, which sharply absorbs light with wavelengths in the range of approximately 400 nm to 450 nm.

[0007] International Publication No. 2018 / 088561 Patent No. 6232161 Special Publication No. 2007-535708

[0008] The technologies described in Patent Documents 1 and 2 need to be reconsidered from the viewpoint of the blocking properties of light in the short wavelength region of 410 nm or less. Also, the violet light vertical cutoff filter described in Patent Document 3 is thought to have low transmittance of visible light with a wavelength of 450 nm or more. In addition, the technologies described in Patent Documents 1 to 3 need to be reconsidered from the viewpoint of cleaning of the optical filter or durability during the manufacturing process of the optical filter.

[0009] Therefore, the present invention provides a light-absorbing composition, a light-absorbing film, and an optical filter that are advantageous from the viewpoint of reproducing human visual sensitivity, particularly light absorption characteristics in the short wavelength region, and are also advantageous from the viewpoint of durability during cleaning or manufacturing processes of the optical filter.

[0010] The present invention provides a light-absorbing composition comprising: an ultraviolet-absorbing compound having a hydroxy group and a carbonyl group in the molecule; a metal component; polyvinyl butyral; and an isocyanate, wherein at least a portion of the metal component is bonded to an organic oxy group.

[0011] The present invention also provides a method for producing the above light-absorbing composition, which comprises adding an ultraviolet-absorbing compound having a hydroxy group and a carbonyl group in the molecule, a compound containing a metal component, polyvinyl butyral, and an isocyanate to an organic solvent and mixing them.

[0012] The present invention also provides a light-absorbing film comprising: an ultraviolet-absorbing compound having a hydroxy group and a carbonyl group in the molecule; a metal component; and a resin having a urethane bond, wherein at least a portion of the metal component is bonded to an organic oxy group.

[0013] The present invention also provides an optical filter comprising the above light-absorbing film.

[0014] The present invention also provides a method for manufacturing an optical filter including the above-described light-absorbing film, the method comprising either the following steps (i) or (ii): (i) forming the light-absorbing film on an imaging element or an optical component, and (ii) forming the light-absorbing film on a substrate and peeling the light-absorbing film from the substrate.

[0015] The light-absorbing composition is advantageous from the viewpoint of reproducing human visibility, particularly the absorption characteristics of light in the short wavelength region, and is also advantageous from the viewpoint of durability during cleaning or manufacturing of optical filters. In addition, the light-absorbing film and the optical filter are advantageous from the viewpoint of reproducing human visibility, particularly the absorption characteristics of light in the short wavelength region. Furthermore, the light-absorbing film and the optical filter are also advantageous from the viewpoint of durability, as they are less susceptible to scratches even when the surface is cleaned or wiped.

[0016] FIG. 1 is a cross-sectional view showing an example of a light-absorbing film according to the present invention. FIG. 2A is a cross-sectional view showing an example of an optical filter according to the present invention. FIG. 2B is a cross-sectional view showing an example of an optical filter according to the present invention. FIG. 3 is a transmission spectrum of an optical filter according to Example 1. FIG. 4 is a transmission spectrum of an optical filter according to Example 5. FIG. 5 is a transmission spectrum of an optical filter according to Example 7. FIG. 6 is a transmission spectrum of an optical filter according to Example 9. FIG. 7 is a transmission spectrum of an optical filter according to Example 11. FIG. 8 is a reflection spectrum of an optical filter according to Example 1. FIG. 9 is a reflection spectrum of an optical filter according to Example 5. FIG. 10 is a reflection spectrum of an optical filter according to Example 7. FIG. 11 is a reflection spectrum of an optical filter according to Example 9. FIG. 12 is a reflection spectrum of an optical filter according to Example 11. FIG. 13 is a transmission spectrum of a transparent glass substrate.

[0017] If an optical filter for an imaging device using a solid-state imaging element can effectively absorb light in the short wavelength region of 410 nm or less, the value of the optical filter can be further enhanced from the perspective of reproducing human visual sensitivity. According to the optical filter described in Patent Document 1, the wavelength at which the spectral transmittance is 50% in the wavelength range of 350 nm to 450 nm is less than 400 nm. According to the optical filter described in Patent Document 2, the wavelength at which the spectral transmittance is 50% in the wavelength range of 350 nm to 450 nm is in the range of approximately 390 nm to 415 nm. Based on these facts, it is difficult to say that the optical filters described in Patent Documents 1 and 2 are advantageous in terms of effectively absorbing light in the short wavelength region of 410 nm or less. The violet light vertical cutoff filter described in Patent Document 3 may be able to effectively absorb light in the short wavelength region of 410 nm or less, but the transmittance of the filter for visible light with a wavelength of 450 nm or more is considered low.

[0018] Therefore, the present inventors have conducted extensive research to develop a light-absorbing composition that is advantageous from the viewpoint of reproducing human visual sensitivity, particularly from the viewpoint of effectively absorbing light in the short wavelength region of 410 nm or less. As a result of extensive trial and error, the present inventors have newly discovered that a light-absorbing composition containing a predetermined ultraviolet-absorbing compound and a metal component is advantageous from the viewpoint of effectively absorbing light in the short wavelength region.

[0019] In addition, the present inventors further investigated whether it is possible to impart advantageous properties to the light-absorbing composition containing the above-mentioned UV-absorbing compound and metal component in terms of durability during the cleaning or manufacturing process of an optical filter. For example, optical filters may be cleaned by wiping with a wipe or cloth, such as a wiping cloth impregnated with an organic solvent such as alcohol or acetone, or with a microfiber. Furthermore, during the manufacturing process of an optical filter, a portion containing the light-absorbing composition or a solidified light-absorbing composition may come into contact with another component or the like. Given these circumstances, it is important for the light-absorbing composition containing the above-mentioned UV-absorbing compound and metal component to have advantageous properties in terms of durability or solvent resistance regarding the mechanical strength of the surface during the cleaning or manufacturing process of an optical filter, in order to increase the added value of the light-absorbing composition, light-absorbing film, or optical filter. For example, it is important for the light-absorbing composition to have advantageous properties in terms of scratch resistance and solvent resistance during the cleaning or manufacturing process of an optical filter.

[0020] On the other hand, it is not easy to simultaneously impart advantageous properties from the viewpoint of durability during cleaning or manufacturing of optical filters and reproduce human visual sensitivity, particularly effective absorption of light in the short wavelength region with a wavelength of 410 nm or less. This is because, when selecting a component to be added to a light-absorbing composition to impart durability during cleaning or manufacturing of optical filters, careful consideration must be given to whether the effective absorption of light in the short wavelength region with a wavelength of 410 nm or less is impaired due to an interaction between the component and an ultraviolet-absorbing compound, etc. From this perspective, the present inventors have undertaken extensive trial and error. As a result, the present inventors have newly identified an additive component in a light-absorbing composition containing the ultraviolet-absorbing compound and a metal component that can impart advantageous properties from the viewpoint of durability during cleaning or manufacturing of optical filters without impairing the effective absorption of light in the short wavelength region with a wavelength of 410 nm or less, thereby completing the present invention.

[0021] Hereinafter, embodiments of the present invention will be described. Note that the following description is for illustrative purposes only and the present invention is not limited to the following embodiments.

[0022] The light-absorbing composition according to the present invention contains an ultraviolet-absorbing compound having a hydroxy group and a carbonyl group in its molecule, a metal component, polyvinyl butyral (PVB), and an isocyanate. In this specification, isocyanate refers to a compound containing an -N=C=O (isocyanate group) in its molecule. Additionally, at least a portion of the metal component is bonded to an organic oxy group. Typically, at least a portion of the metal component is bonded to an oxygen atom in the organic oxy group. This allows a light-absorbing film or optical filter prepared using the light-absorbing composition to effectively absorb light in the wavelength region of approximately 410 nm or less. Additionally, the light-absorbing film or optical filter can exhibit high transmittance in the visible light region. Therefore, this light-absorbing composition is advantageous from the perspective of reproducing human visual sensitivity.

[0023] Advantageous conditions for an ultraviolet-absorbing compound include an appropriate light absorption range and transmittance range, photochemical stability, low enough photosensitization within the range of use to have no adverse effects, and thermochemical stability. From these perspectives, the light absorption mechanism of ultraviolet-absorbing compounds is thought to utilize a hydrogen transfer reaction (intramolecular hydrogen abstraction reaction) of a hydroxy group within the molecule due to photoexcitation. Examples of ultraviolet-absorbing compounds that exhibit this mechanism include compounds such as hydroxybenzophenone, salicylic acid, hydroxyphenylbenzotriazole, hydroxyphenyltriazine, and substituted acrylonitrile. In hydroxybenzophenone and salicylic acid, a reaction involving hydrogen transfer between a hydroxy group and a carbonyl group contained within the molecule is involved in the absorption of ultraviolet light, etc. In contrast, in hydroxyphenylbenzotriazole, hydroxyphenyltriazine, and substituted acrylonitrile, a reaction involving hydrogen transfer between a hydroxy group and a nitrogen atom contained within the molecule is involved in the absorption of ultraviolet light, etc. These UV-absorbing compounds contain a hydroxy group with an unshared electron pair in their molecules, which is presumed to cause interactions such as partial complexation with the coexisting metal component or hydrogen donor. In systems such as light-absorbing compositions containing UV-absorbing compounds and their cured products, a comparison was made between a case in which the UV-absorbing compound having a hydroxy group is present alone and a case in which a metal component or hydrogen donor and a UV-absorbing compound having a hydroxy group are present together. This comparison supports the above presumption, revealing differences in their optical properties, such as their light absorption spectra and light transmission spectra. In particular, it was found that a light-absorbing film or optical filter equipped with a light-absorbing film obtained by curing a light-absorbing composition containing a UV-absorbing compound having a hydroxy group and a carbonyl group in its molecule and a metal component exhibits a phenomenon in which a portion of the light absorption band in the wavelength range of 300 to 500 nm shifts to the longer wavelength side. Therefore, such light-absorbing films have advantageous properties for effectively and appropriately absorbing light with wavelengths of 410 nm or shorter.Furthermore, when the light absorption band shifts to the longer wavelength side, for example, the phenomenon of the maximum absorption wavelength shifting to the longer wavelength side within the wavelength range of 300 nm to 500 nm of the transmission spectrum, or the phenomenon of the wavelength at which the transmittance is 50% (UV cutoff wavelength) shifting to the longer wavelength side may become apparent. Thus, with the light-absorbing composition according to the present invention, the light-absorbing film that is a cured product thereof, and the optical filter equipped with the light-absorbing film, the absorption characteristics inherent to the ultraviolet-absorbing compound are adjusted so as to effectively absorb light in the short wavelength region. As a result, the spectral transmittance of such a light-absorbing film or optical filter is likely to be more appropriate when used with a solid-state imaging device or the like.

[0024] As described above, the light-absorbing composition contains PVB and isocyanate. This makes the light-absorbing composition more likely to have advantageous properties from the viewpoint of durability during cleaning or manufacturing of optical filters. In particular, the light-absorbing composition containing PVB and isocyanate is advantageous from the viewpoint of improving scratch resistance and solvent resistance during cleaning or manufacturing of optical filters. Moreover, even if the light-absorbing composition contains PVB and isocyanate, this does not prevent the absorption properties inherent to the ultraviolet-absorbing compound from being adjusted so that light in the short-wavelength region can be effectively absorbed by the above-mentioned mechanism of action.

[0025] PVB, for example, tends to have high transparency and can have high compatibility with organic solvents and the like. In addition, PVB has high weather resistance and high light resistance, and when a light-absorbing composition contains PVB, the light-absorbing film and optical filter obtained from the light-absorbing composition also tend to exhibit high weather resistance and light resistance. Furthermore, PVB can exhibit advantageous properties as a binder for functional components such as the above-mentioned ultraviolet-absorbing compound.

[0026] PVB exhibits good adhesion to the surfaces of substrates such as lenses or other optical elements and transparent dielectric substrates, and therefore the light-absorbing composition may have advantageous properties for fabricating composite optical elements or optical components that combine multiple members or components.

[0027] PVB is represented, for example, by the following structural formula: In the structural formula, k is the molar fraction [%] of structural units having a vinyl butyral group, m is the molar fraction [%] of structural units derived from vinyl alcohol and having a hydroxy group, and n is the molar fraction [%] of structural units derived from vinyl acetate.

[0028]

[0029] PVB is obtained by reacting polyvinyl alcohol (PVA) with butyraldehyde. Since it is not possible to esterify all of the vinyl groups in PVA, PVB contains some groups containing hydroxyl groups.

[0030] The number average molecular weight of the PVB contained in the light-absorbing composition is not limited to a specific value. The number average molecular weight is, for example, 12.0 × 10 4 This makes it easy to form a film from the light-absorbing composition, and the haze of the light-absorbing film and optical filter obtained from the light-absorbing composition tends to be low. The number average molecular weight of PVB is, for example, 1.0 × 10 or less. 4 As a result, the light-absorbing composition is less likely to shrink during curing, and the haze of the light-absorbing film and optical filter obtained from the light-absorbing composition is likely to be low. The number average molecular weight of PVB is 1.2 × 10 4 or more, and may be 1.5 × 10 4 The number average molecular weight of PVB may be 11.5 × 10 or more. 4 or less, or 11.0 × 10 4 The number average molecular weight of PVB can be measured, for example, in accordance with Japanese Industrial Standards (JIS) K7252-1:2016.

[0031] The butyralization degree of PVB is not limited to a specific value. The butyralization degree is, for example, 60 mol% or more. This makes it easy to adjust the hydrophobicity and toughness of the surface of a light-absorbing film or optical filter obtained from the light-absorbing composition to a desired level. The butyralization degree is preferably 65 mol% or more. The butyralization degree is, for example, 90 mol% or less. This makes it easy for a desired amount of hydroxy groups to be present in the PVB. The butyralization degree is preferably 80 mol% or less. The butyralization degree of PVB is, for example, a value expressed as a percentage, which is the molar fraction calculated by dividing the amount of ethylene groups to which butyral groups are bonded by the total amount of ethylene groups in the main chain. The butyralization degree can be calculated, for example, by measuring the acetylation degree and the hydroxyl group content according to a method in accordance with JIS K 6728 (Testing methods for polyvinyl butyral), calculating the molar fraction from the measurement results, and then subtracting the acetylation degree and the hydroxyl group content from 100 mol%.

[0032] The hydroxy group content in PVB is not limited to a specific value. The content is, for example, 10 mol% or more. This makes it easier for a sufficient amount of hydroxy groups to be present in the PVB to react with isocyanate during curing of the light-absorbing composition, as described below. The hydroxy group content in PVB is preferably 20 mol% or more. The hydroxy group content in PVB is, for example, 50 mol% or less. This makes it easier for the PVB to contain a desired amount of butyral groups from the perspective of toughness. The hydroxy group content in PVB is preferably 40 mol% or less. The hydroxy group content can be calculated, for example, according to a method in accordance with JIS K6728 (Test Method for Polyvinyl Butyral).

[0033] Examples of PVB include S-LEC KS-1, S-LEC KS-10, S-LEC BX-L, S-LEC BX-1, S-LEC BL-S, and S-LEC BL-1 manufactured by Sekisui Chemical Co., Ltd. S-LEC is a registered trademark. Other examples of PVB include Mobital B20H, Mobital B30T, Mobital B30H, and Mobital B45H manufactured by Kuraray Co., Ltd. Mobital is a registered trademark. In the light-absorbing composition, one or more types of PVB are selected from these PVBs or are mixed and used.

[0034] The isocyanate contained in the light-absorbing composition has, for example, two or more isocyanate groups in the molecule, and each isocyanate group is bonded to a carbon atom. As described above, the PVB molecule contains a hydroxy group, and the PVB can undergo a crosslinking reaction with the isocyanate. This crosslinking reaction consumes the hydroxy groups of the PVB, and a three-dimensional network structure can be formed. Specifically, as shown in the following reaction formula, the isocyanate group R 1 -N=C=O and a hydroxy group R contained in PVB 2 By reaction with —OH, a urethane bond R 1 -NH-COO-R 2 This increases the surface hardness of the cured product of the light-absorbing composition, and can provide advantageous mechanical properties and solvent resistance from the viewpoint of durability during cleaning or manufacturing of optical filters.

[0035]

[0036] The presence or absence of a urethane bond can be determined by, for example, obtaining an infrared spectrum of a sample by a method such as Fourier transform infrared spectroscopy (FT-IR) and analyzing the presence or absence or intensity of a peak characteristic of a urethane bond in the infrared spectrum. -1 ~3000cm -1 within the range (e.g., 3290 cm -1 ) a peak due to the stretching vibration of N—H in -1 ~1691cm -1 within the range (e.g., 1725 cm -1 and 1705 cm-1 ) and a peak due to the stretching vibration of C═O (amide I) at 1530 cm -1 These are peaks due to the deformation vibration of N--H (amide II) in the vicinity.

[0037] The isocyanate contained in the light-absorbing composition is not limited to a specific isocyanate. An isocyanate is a compound having an isocyanate group in its molecule. Examples of isocyanates include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), phenylene diisocyanate, dinaphthalene diisocyanate, isophorone diisocyanate, and xylylene diisocyanate. Other examples of isocyanates include trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, and trimethylhexamethylene diisocyanate. The isocyanate may also be an alicyclic polyisocyanate. Examples of cycloaliphatic polyisocyanates are isophorone diisocyanate, dicyclohexylmethane diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, and bis(isocyanatomethyl)norbornane. The isocyanate may also be an araliphatic polyisocyanate. Examples of araliphatic polyisocyanates are xylylene diisocyanate, tetramethylxylylene diisocyanate, and ω,ω'-diisocyanato-1,4-diethylbenzene.

[0038] As described above, in the light-absorbing composition, at least a part of the metal component is bonded to the organic oxy group, and the light-absorbing composition includes a compound containing a metal component bonded to the organic oxy group. Here, the compound containing a metal component bonded to the organic oxy group is generally (R k -O) n -M, where M represents a metal component such as a metal atom or a metal ion. (R k -O) n The - group represents n organic oxy groups (or collectively referred to as organic oxy groups, the same applies hereinafter), and R krepresents an organic group containing at least a carbon atom (C) and a hydrogen atom (H), and n represents the number of atoms bonded to or coordinated with the metal component M, and one or more organic oxy groups may be bonded to or coordinated with the metal component M. k Two or more O (oxygen) groups may be contained within the —O)— group, and the organic oxy group may be bonded or coordinated to the metal component M via these two or more O (oxygen) groups. k is a bonding or coordinating organic oxy group (R k Each —O)— may be the same or different, and multiple organic oxy groups may be bonded without the metal component M being interposed therebetween. The organic oxy group is not particularly limited as long as it satisfies the above conditions, and examples thereof include alkoxy groups such as methoxy, ethoxy, propyloxy, phenoxy, and alkylphenoxy groups, and vinyl groups. The organic oxy group is a group formed by bonding an organic group R k The metal component M may contain a partial structure (group) such as an acyl group, an acetyl group, a ketone group, a vinyl group, a propionyl group, an acrylyl group, an acetoxy group, an acryloyl group, an ethyl acetate group, an ethyl acetoacetate group, an acetylacetone group, or other ester or ether. Alternatively, the metal component M may be an organic oxy group containing one or more groups selected from the above. The metal component M may contain at least one selected from the group consisting of metal atoms or ions of metals such as Li, Na, Mg, Ca, Sr, Ba, Ge, Sn, Pb, Al, Ga, In, Tl, Zn, Cd, Cu, Ag, Au, Ni, Pd, Pt, Co, Rh, Ir, Fe, Mn, Cr, Mo, W, V, Nb, Ta, Ti, and Zr.

[0039] The arrangement of the hydroxy group and the carbonyl group in the ultraviolet absorbing compound is not limited to a specific arrangement. In the ultraviolet absorbing compound, the hydroxy group and the carbonyl group are desirably arranged with one to three atoms between them. This is thought to facilitate hydrogen transfer between the hydroxy group and the carbonyl group in the ultraviolet absorbing compound. Therefore, the phenomenon of the light absorption band in the wavelength range of 300 to 500 nm shifting to the longer wavelength side is likely to occur effectively. As a result, the light absorbing film obtained by curing the light absorbing composition is likely to more reliably and effectively absorb light with a wavelength of 410 nm or less.

[0040] The ultraviolet absorbing compound is not limited to a specific compound as long as it has a hydroxy group and a carbonyl group in its molecule. The ultraviolet absorbing compound is preferably a compound that does not easily aggregate even when mixed with a metal component.

[0041] The ultraviolet absorbing compound desirably contains a benzophenone-based compound represented by the following formula (A1): In this case, a light absorbing film or optical filter produced using the light absorbing composition is more likely to effectively absorb light in the short wavelength region having a wavelength of 410 nm or less.

[0042]

[0043] In formula (A1), R 11 , R 12 , R 21 , and R 22 At least one of R is a hydroxy group. 11 , R 12 , R 21 , or R 22 is a functional group other than a hydroxy group, a plurality of R 11 , multiple R 12 , multiple R 21 , or multiple R 22 may be present, and R 11 , R 12 , R 21 , and R 22 At least one of them may not be present.

[0044] R 11 , R 12 , R21 , or R 22 is a functional group other than a hydroxy group, the functional group is, for example, a carboxyl group, an aldehyde group, a halogen atom, an alkyl group having 1 to 12 carbon atoms, an alkyl group having 1 to 12 carbon atoms in which one or more hydrogen atoms are substituted with halogen atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms in which one or more hydrogen atoms are substituted with halogen atoms.

[0045] More preferably, the ultraviolet absorbing compound includes a benzophenone-based compound represented by the following formula (A2): In this case, a light-absorbing film or optical filter produced using the light-absorbing composition is more likely to effectively absorb light in the short wavelength region of 410 nm or less.

[0046]

[0047] In formula (A2), R 31 is a hydrogen atom, a hydroxy group, a carboxyl group, an aldehyde group, a halogen atom, a group having a halogen atom, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. 41 and R 42 may be a hydroxy group, a carboxyl group, an aldehyde group, a group having a halogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms; R 41 and R 42 In formula (A2), a plurality of R 41 may be present, and multiple R 42 may be present. The group having a halogen atom may be a halogenated alkyl group in which at least one hydrogen atom in the alkyl group is substituted with a halogen atom. The group having a halogen atom may be a halogenated aryl group in which at least one hydrogen atom in the aryl group is substituted with a halogen atom. The group having a halogen atom may be a halogenated alkoxy group in which at least one hydrogen atom in the alkoxy group is substituted with a halogen atom.

[0048] The benzophenone compound represented by formula (A1) or formula (A2) is not limited to a specific compound, and may be, for example, at least one selected from the group consisting of 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-4'-chlorobenzophenone, 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-n-octoxybenzophenone, 2-hydroxy-5-chlorobenzophenone, and 2,4-dibenzoylresorcinol.

[0049] The ultraviolet absorbing compound may contain a salicylic acid compound represented by the following formula (B): In this case, a light absorbing film or optical filter produced using the light absorbing composition is more likely to effectively absorb light in the short wavelength region around 410 nm.

[0050]

[0051] In formula (B), R 51 may be a hydroxy group, a carboxy group, a group containing a halogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. 51 may be present, and R 51 In formula (B), R may not be present. 52is a hydrogen atom, an aryl group, or a halogenated aryl group in which one or more hydrogen atoms have been substituted with a halogen atom. The halogen-containing group may be a halogenated alkyl group in which at least one hydrogen atom in the alkyl group has been substituted with a halogen atom. The halogen-containing group may be a halogenated aryl group in which at least one hydrogen atom in the aryl group has been substituted with a halogen atom. The halogen-containing group may be a halogenated alkoxy group in which at least one hydrogen atom in the alkoxy group has been substituted with a halogen atom.

[0052] The salicylic acid compound represented by formula (B) is not limited to a specific compound, and includes, for example, at least one selected from the group consisting of phenyl salicylate, 4-butylphenyl salicylate, and octylphenyl salicylate.

[0053] The metal component is not limited to a specific metal component. The metal component is typically a component that does not aggregate in the light-absorbing composition and the light-absorbing film formed using the light-absorbing composition, and is thermally and chemically stable. In addition, the metal component is typically a component that can interact with the above-mentioned ultraviolet-absorbing compound.

[0054] The metal component includes at least one selected from the group consisting of, for example, Li, Na, Mg, Ca, Sr, Ba, Ge, Sn, Pb, Al, Ga, In, Tl, Zn, Cd, Cu, Ag, Au, Ni, Pd, Pt, Co, Rh, Ir, Fe, Mn, Cr, Mo, W, V, Nb, Ta, Ti, and Zr. In this case, the metal component is likely to interact with the ultraviolet absorbing compound.

[0055] Content C of metal component in light-absorbing composition M is not limited to a specific value. M is, for example, 0.005% to 2% by mass. This makes it easier for a light-absorbing film or optical filter produced using the light-absorbing composition to more reliably absorb light in the short wavelength region of 410 nm or less. Mis preferably 0.01% to 1%, more preferably 0.01% to 0.5%, and even more preferably 0.01% to 0.3%.

[0056] Content C of ultraviolet absorbing compound in light absorbing composition UV is not limited to a specific value. UV is, for example, 0.1% to 20% by mass. This makes it possible for a light-absorbing film or optical filter produced using the light-absorbing composition to more reliably and effectively absorb light in the short wavelength region of 410 nm or less. UV is preferably 0.1% to 15%, more preferably 0.2 to 10%, even more preferably 0.5% to 10%, and particularly preferably 1% to 10%.

[0057] In the light-absorbing composition, the ratio R of the content of the ultraviolet-absorbing compound to the content of the metal component UV / M is not limited to a specific value. UV / M is, for example, 5 to 300 on a mass basis. This makes it easier for a light-absorbing film or optical filter produced using the light-absorbing composition to more reliably and effectively absorb light in the short wavelength region of 410 nm or less. UV / M is preferably 10 to 300, more preferably 20 to 300, and even more preferably 30 to 280.

[0058] In the light-absorbing composition, the ratio R of the mass of isocyanate to the mass of PVB I / P is not limited to a specific value. I / P is, for example, 0.05 to 3.0. This makes it easier for the surface hardness of the cured product of the light-absorbing composition to be increased by the crosslinking reaction between the PVB and the isocyanate. I / P is preferably 0.05 to 3.0, more preferably 0.1 to 0.3, and even more preferably 0.2 to 3.0.

[0059] In the light-absorbing composition, the ratio R of the mass of the isocyanate to the mass of the ultraviolet-absorbing compound I / UV is not limited to a specific value. I / UVis, for example, 0.1 to 3.0. This makes it easier to increase the surface hardness of the cured product of the light-absorbing composition, and makes it easier to achieve advantageous mechanical properties and solvent resistance from the viewpoint of durability during cleaning or manufacturing processes of the optical filter. I / UV is preferably 0.2 to 3.0, and more preferably 0.25 to 3.0.

[0060] The method for producing the light-absorbing composition is not limited to a specific method. The light-absorbing composition can be produced, for example, by a method including adding an ultraviolet-absorbing compound having a hydroxy group and a carbonyl group in the molecule, a compound containing a metal component, polyvinyl butyral, and an isocyanate to an organic solvent and mixing them.

[0061] The light-absorbing composition can be used to provide, for example, a light-absorbing film 10 as shown in FIG. 1 . The light-absorbing film 10 can be obtained, for example, by curing the light-absorbing composition. The light-absorbing film 10 contains an ultraviolet-absorbing compound having a hydroxy group and a carbonyl group in its molecule, a metal component, and a resin having a urethane bond. In the light-absorbing film 10, at least a portion of the metal component is bonded to an organic oxy group. At least a portion of the metal component is bonded to an oxygen atom in the organic oxy group. This makes it easy for the light-absorbing film 10 to effectively absorb light in the short wavelength region of 410 nm or less. In addition, since the light-absorbing film 10 contains a resin having a urethane bond, the light-absorbing film 10 is likely to have advantageous properties in terms of improving durability or solvent resistance when cleaning optical filters.

[0062] As described above, in the light absorbing film 10, at least a part of the metal component is bonded to the organic oxy group, and the light absorbing film 10 includes a compound containing a metal component bonded to the organic oxy group. Here, the compound containing a metal component bonded to the organic oxy group is generally (R k -O) n -M, where M represents a metal component such as a metal atom or a metal ion. (R k -O) n The - group represents n organic oxy groups (or collectively referred to as organic oxy groups, the same applies hereinafter), and R krepresents an organic group containing at least a carbon atom (C) and a hydrogen atom (H), and n represents the number of atoms bonded to or coordinated with the metal component M, and one or more organic oxy groups may be bonded to or coordinated with the metal component M. k Two or more O (oxygen) groups may be contained within the —O)— group, and the organic oxy group may be bonded or coordinated to the metal component M via these two or more O (oxygen) groups. k is a bonding or coordinating organic oxy group (R k Each —O)— may be the same or different, and multiple organic oxy groups may be bonded without the metal component M being interposed therebetween. The organic oxy group is not particularly limited as long as it satisfies the above conditions, and examples thereof include alkoxy groups such as methoxy, ethoxy, propyloxy, phenoxy, and alkylphenoxy groups, and vinyl groups. The organic oxy group is a group formed by bonding an organic group R k The metal component M may contain a partial structure (group) such as an acyl group, an acetyl group, a ketone group, a vinyl group, a propionyl group, an acrylyl group, an acetoxy group, an acryloyl group, an ethyl acetate group, an ethyl acetoacetate group, an acetylacetone group, or other ester or ether. Alternatively, the metal component M may be an organic oxy group containing one or more groups selected from the above. The metal component M may contain at least one selected from the group consisting of metal atoms or ions of metals such as Li, Na, Mg, Ca, Sr, Ba, Ge, Sn, Pb, Al, Ga, In, Tl, Zn, Cd, Cu, Ag, Au, Ni, Pd, Pt, Co, Rh, Ir, Fe, Mn, Cr, Mo, W, V, Nb, Ta, Ti, and Zr.

[0063] In the ultraviolet absorbing compound of the light absorbing film 10, the hydroxy group and the carbonyl group are preferably spaced apart by 1 to 3 atoms, which makes it easier to improve the ability of the light absorbing film 10 to absorb light in the wavelength region of 410 nm or less.

[0064] The ultraviolet absorbing compound in the light absorbing film 10 includes, for example, a benzophenone-based compound represented by the above formula (A1), which makes it easy to improve the ability of the light absorbing film 10 to absorb light in the wavelength region of 410 nm or less.

[0065] The ultraviolet absorbing compound in the light absorbing film 10 preferably contains a benzophenone-based compound represented by the above formula (A2), which makes it easy to particularly improve the ability of the light absorbing film 10 to absorb light in the wavelength region of 410 nm or less.

[0066] The ultraviolet absorbing compound in the light absorbing film 10 may contain, for example, a salicylic acid compound represented by the above formula (B). In this case, the ability of the light absorbing film 10 to absorb light in the wavelength region of 410 nm or less is easily improved.

[0067] The metal component in the light absorbing film 10 includes at least one selected from the group consisting of, for example, Li, Na, Mg, Ca, Sr, Ba, Ge, Sn, Pb, Al, Ga, In, Tl, Zn, Cd, Cu, Ag, Au, Ni, Pd, Pt, Co, Rh, Ir, Fe, Mn, Cr, Mo, W, V, Nb, Ta, Ti, and Zr.

[0068] In the light-absorbing film 10, the ratio r of the content of the ultraviolet absorbing compound to the content of the metal component UV / M is not limited to a specific value. UV / M is, for example, 5 to 300 on a mass basis. This makes it easier for a light-absorbing film or optical filter produced using the light-absorbing composition to more reliably absorb light in the short wavelength region of 410 nm or less. UV / M is preferably 10 to 300, more preferably 20 to 300, and even more preferably 30 to 280.

[0069] Transmittance T of the light absorbing film 10 400 is, for example, 5% or less. This is advantageous from the viewpoint of reproducing the human visual sensitivity. 400 is the transmittance at a wavelength of 400 nm in the transmission spectrum at an incident angle of 0°. 400 is preferably 4.5% or less, and more preferably 4% or less.

[0070] The content of the ultraviolet absorbing compound in the light absorbing film 10 is not limited to a specific value. The content is, for example, 0.1% to 90%, preferably 0.5% to 80%, and more preferably 2% to 70%, by mass.

[0071] The content of the metal component in the light absorbing film 10 is not limited to a specific value. The content is, for example, 0.005% to 5%, preferably 0.01% to 4%, and more preferably 0.03% to 3%, by mass.

[0072] In the light-absorbing film 10, the ratio r of the mass of isocyanate to the mass of PVB I / P is not limited to a specific value. I / P is, for example, 0.05 to 3.0, preferably 0.05 to 2.5, more preferably 0.05 to 2.0, and even more preferably 1.0 to 2.0.

[0073] In the light-absorbing film 10, the ratio r of the mass of the isocyanate to the mass of the ultraviolet absorbing compound I / UV is not limited to a specific value. I / UV is, for example, 0.1 to 3.0, preferably 0.2 to 2.8, and more preferably 0.2 to 2.5.

[0074] The thickness of the light-absorbing film 10 is not limited to a specific value and may be, for example, 0.5 μm to 500 μm, 1 μm to 100 μm, or 1 μm to 50 μm.

[0075] In the manufacture of the light-absorbing film 10, the method for curing the light-absorbing composition is not limited to a specific method. For example, the conditions for curing the light-absorbing composition are adjusted so that a crosslinking reaction occurs between the PVB contained in the light-absorbing composition and the isocyanate. As a result, the light-absorbing film 10 contains a resin having a urethane bond. For example, the light-absorbing composition may be cured by heating at a predetermined temperature. In this case, the predetermined temperature is, for example, 80°C or higher, preferably 100°C or higher, more preferably 120°C or higher, and even more preferably 140 to 180°C. This tends to prevent deterioration of the ultraviolet-absorbing compound while providing the light-absorbing film 10 with advantageous properties in terms of durability in cleaning optical filters.

[0076] 1 and 2A, for example, optical filters 1a and 1b can be provided that include a light absorbing film 10. The optical filters 1a and 1b tend to effectively absorb light in the short wavelength region of 410 nm or less.

[0077] In the transmission spectra of the optical filters 1a and 1b at an incident angle of 0 degrees, the transmittance T 410 is, for example, 20% or less, preferably 15% or less, and more preferably 10% or less.

[0078] In the transmission spectrum of the optical filters 1a and 1b at an incident angle of 0 degrees, the maximum value T of the transmittance in the wavelength range of 300 to 380 nm M 300-380 is, for example, 3% or less. This makes it easy for the optical filter to effectively absorb light in the wavelength range shorter than 400 nm. M 300-380 is preferably 2% or less, and more preferably 1% or less.

[0079] In the transmission spectrum of the optical filters 1a and 1b at an incident angle of 0 degrees, the wavelength at which the transmittance is 50% in the wavelength range of 300 to 520 nm is defined as the ultraviolet cutoff wavelength λ UV In the optical filters 1a and 1b, for example, 405 nm≦λ UV≦500 nm. This allows the light absorbing film 10 to effectively absorb light in the short wavelength region around 410 nm, and in an imaging device used in combination with an imaging element, light in a wavelength region that is difficult for humans to perceive is easily cut. The optical filters 1a and 1b preferably satisfy the condition of 405 nm≦λ UV ≦490 nm, and more preferably 405 nm≦λ UV The condition of ≦480 nm is met.

[0080] In the transmission spectrum of the optical filters 1a and 1b at an incident angle of 0 degrees, the minimum value T of the transmittance in the wavelength range of 480 to 600 nm m 480-600 is, for example, 85% or more. This allows the optical filters 1 a and 1 b to appropriately transmit visible light, and in an imaging device used in combination with an imaging element, it is possible to increase the light flux reaching the imaging element from the subject.

[0081] Minimum transmittance T m 480-600 is preferably 86% or more, and more preferably 87% or more.

[0082] The transmission spectrum obtained by irradiating light having a wavelength in the range of 300 nm to 1200 nm onto the optical filters 1a and 1b at an incident angle of 0° may satisfy the following requirements (ia), (ii-a), (iii-a), (iv-a), (va), and (vi-a): (ia) The maximum value T of the transmittance in the wavelength range of 300 nm to 380 nm M 300-380 (ii-a) Transmittance T at a wavelength of 400 nm 400 (iii-a) Transmittance T at a wavelength of 410 nm 410 (iv-a) The wavelength λ at which the transmittance becomes 50% within the wavelength range of 350 nm to 500 nm UV [nm] is in the range of 405 nm to 490 nm. (va) The minimum value T of the transmittance in the wavelength range of 480 to 600 nm m 480-600 is 85% or more. (vi-a) Wavelength (λ UV -10) Transmittance T at nm0 UV- For the wavelength (λ UV +10) Transmittance T at nm 0 UV+ The ratio T 0 UV+ / T 0 UV- is 1.8 or more.

[0083] By satisfying the above requirement (ia), the optical filters 1a and 1b can exhibit high ultraviolet absorption properties.

[0084] By satisfying the requirements (ii-a) and (iii-a) above in addition to the requirement (ia), the optical filters 1a and 1b can exhibit higher ultraviolet absorption properties. In particular, the optical filters 1a and 1b can be applied to optical filter applications that require higher ultraviolet absorption performance. 400 is preferably 4% or less.

[0085] By satisfying the above requirement (iv-a), the optical filters 1a and 1b can exhibit high ultraviolet absorption properties, and the spectrum perceived by the imaging element tends to partially match the spectrum corresponding to the human visual sensitivity. UV is preferably 420 nm to 490 nm, and more preferably 420 nm to 450 nm. In this case, purple fringing is easily suppressed in the obtained image. Purple fringing is a color bleeding that appears approximately purple, particularly around the contours of a subject. In addition, the transmittance of light in the human visible light range can be increased, making it easier to obtain bright images.

[0086] By satisfying the above requirement (va), the transmittance of light in the human visible light range tends to be high, making it easier to obtain brighter images. In particular, the transmittance of the wavelength range corresponding to the maximum sensitivity on the human luminosity curve tends to be high, making it easier for people to perceive brightness when viewing an image.

[0087] By satisfying the above requirement (vi-a), the wavelength λ UVSince the transmission spectrum changes sharply in the vicinity of the UV cutoff wavelength, ultraviolet rays that are invisible to humans can be more sharply blocked, and the amount of light included in the visible light range can be increased. 0 UV+ / T 0 UV- is preferably 1.9 or more, more preferably 2.0 or more, even more preferably 2.2 or more, and particularly preferably 2.4 or more.

[0088] The reflection spectrum obtained by irradiating light having a wavelength in the range of 300 nm to 1200 nm onto the optical filters 1a and 1b at an incident angle of 5° may satisfy the following requirements (ib) and (ii-b). In addition, the reflection spectrum obtained by irradiating light having a wavelength in the range of 300 nm to 1200 nm onto the optical filters 1a and 1b at an incident angle of 40° may satisfy the following requirements (iii-b) and (iv-b). Furthermore, the reflection spectrum obtained by irradiating light having a wavelength in the range of 300 nm to 1200 nm onto the optical filters 1a and 1b at an incident angle of 60° may satisfy the following requirements (vb) and (vi-b). (ib) The maximum value R of reflectance in the wavelength range of 300 nm to 450 nm 5 300-450 (ii-b) The maximum reflectance R in the wavelength range of 300 nm to 600 nm 5 300-600 (iii-b) The maximum reflectance R in the wavelength range of 300 nm to 450 nm 40 300-450 (iv-b) The maximum reflectance R in the wavelength range of 300 nm to 600 nm 40 300-600 (vb) The maximum reflectance R in the wavelength range of 300 nm to 450 nm 60 300-450 (vi-b) The maximum reflectance R in the wavelength range of 300 nm to 600 nm 60 300-600 is less than 35%.

[0089] Satisfying the above requirements (ib) to (vi-b) is extremely advantageous from the viewpoint of preventing ghosts, flares, or noise that occur when light reflected on the surfaces of the optical filters 1a and 1b is repeatedly reflected or refracted, for example, inside the camera module or housing, on the edge, on the lens surface, or the like, before reaching the image sensor. This is the advantage of using a light-absorbing type filter as a filter that cuts (blocks) ultraviolet rays. Maximum value R 5 300-450 is preferably 15% or less. 40 300-450 is preferably 15% or less. 60 300-450 is preferably 20% or less. 5 300-600 is preferably 20% or less. 40 300-600 is preferably 20% or less. 60 300-600 is preferably 25% or less.

[0090] The optical filters 1a and 1b may satisfy the following requirements (ic), (ii-c), (iii-c), (iv-c), and (vc): λ of (ic) 30 UV [nm] is the wavelength at which the transmittance is 50% within the wavelength range of 350 nm to 500 nm in the transmission spectrum when light in the wavelength range of 300 nm to 1200 nm is incident on the optical filter at an incident angle of 30°. 40 UV [nm] is the wavelength at which the transmittance is 50% within the wavelength range of 350 nm to 500 nm in the transmission spectrum when light in the wavelength range of 300 nm to 1200 nm is incident on the optical filter at an incident angle of 40°. 50 UV [nm] is the wavelength at which the transmittance is 50% within the wavelength range of 350 nm to 500 nm in the transmission spectrum when light in the wavelength range of 300 nm to 1200 nm is incident on the optical filter at an incident angle of 50°. 60 UV[nm] is the wavelength at which the transmittance is 50% within the wavelength range of 350 nm to 500 nm in the transmission spectrum when light in the wavelength range of 300 nm to 1200 nm is incident on the optical filter at an incident angle of 60°. 70 UV [nm] is the wavelength at which the transmittance is 50% within the wavelength range of 350 nm to 500 nm in the transmission spectrum when light in the wavelength range of 300 nm to 1200 nm is incident on the optical filter at an incident angle of 70°. 30 UV -λ UV |≦2.4nm (ii-c) |λ 40 UV -λ UV |≦3nm (iii-c)|λ 50 UV -λ UV |≦5nm (iv-c) |λ 60 UV -λ UV |≦9 nm (vc)|λ 70 UV -λ UV |≦18 nm

[0091] A complete absorption type UV cut filter can have the advantage of having a small angular dependency of its transmission spectrum. UV cut filters that use a reflective film made of a dielectric multilayer film to cut UV tend to have a UV cutoff wavelength that shifts toward shorter wavelengths for light incident at an angle. This means that the UV light to be cut may be detected by a sensor depending on the angle of incidence. On the other hand, optical filters 1a and 1b satisfy the above requirements (ic) to (vc), exhibiting little change in UV cutoff wavelength for oblique incidence and being less likely to shift the UV cutoff wavelength toward shorter wavelengths. Therefore, optical filters 1a and 1b not only suppress ghosting and flare, but also facilitate good color reproducibility with minimal in-plane color unevenness, making it easier to obtain high-quality images.

[0092] With respect to (ic), |λ 30 UV -λ UV | is preferably |λ 30 UV -λUV |≦1.6 nm, and more preferably |λ 30 UV -λ UV |≦1.2 nm. Regarding (ii-c), |λ 40 UV -λ UV | is preferably |λ 40 UV -λ UV |≦2.5 nm, and more preferably |λ 40 UV -λ UV |≦2 nm. Regarding (iii-c), |λ 50 UV -λ UV | is preferably |λ 50 UV -λ UV |≦3.5 nm, and more preferably |λ 50 UV -λ UV |≦3 nm. Regarding (iv-c), |λ 60 UV -λ UV | is preferably |λ 60 UV -λ UV |≦6 nm, and more preferably |λ 60 UV -λ UV |≦5 nm. With respect to (vc), |λ 70 UV -λ UV | is preferably |λ 70 UV -λ UV |≦12 nm, and more preferably |λ 70 UV -λ UV |≦9 nm.

[0093] The optical filter 1a is, for example, composed of a light-absorbing film 10 alone. In this case, the optical filter 1a can be used, for example, separately from an imaging element or an optical component. The optical filter 1a may be bonded to the imaging element and the optical component. On the other hand, the optical filter 1a may be constructed by applying the above-mentioned light-absorbing composition to the imaging element or the optical component and curing the light-absorbing composition. In this way, the optical filter 1a may be manufactured by forming the light-absorbing film 10 on the imaging element or the optical component.

[0094] The optical filter 1a can be produced, for example, by peeling off the light-absorbing film 10 formed on a substrate from the substrate. In this case, the material of the substrate may be glass, resin, or metal. The surface of the substrate may be subjected to a surface treatment such as coating with a fluorine-containing compound. In this way, the optical filter 1a may be produced by forming the light-absorbing film 10 on a substrate and then peeling off the light-absorbing film 10 from the substrate.

[0095] 2A , the optical filter 1b includes a light-absorbing film 10 and a transparent dielectric substrate 20. The light-absorbing film 10 is provided parallel to one main surface of the transparent dielectric substrate 20. The light-absorbing film 10 may be in contact with one main surface of the transparent dielectric substrate 20, for example. In this case, the light-absorbing film 10 can be formed, for example, by applying the above-mentioned light-absorbing composition to one main surface of the transparent dielectric substrate 20 and curing the light-absorbing composition.

[0096] The type of transparent dielectric substrate 20 is not limited to a specific type. The transparent dielectric substrate 20 may have absorption in the infrared region. The transparent dielectric substrate 20 may have an average spectral transmittance of 90% or more in the wavelength range of 350 nm to 900 nm, for example. The material of the transparent dielectric substrate 20 is not limited to a specific material, but may be, for example, a specific glass or resin. When the transparent dielectric substrate 20 is made of glass, the transparent dielectric substrate 20 may be, for example, transparent glass made of silicate glass such as soda-lime glass or borosilicate glass, or phosphate glass or fluorophosphate glass containing coloring components such as Cu and Co. Phosphate glass and fluorophosphate glass containing coloring components are, for example, infrared-absorbing glass and are themselves light-absorbing. When the light-absorbing film 10 is used together with a transparent dielectric substrate 20 made of infrared-absorbing glass, the light absorption and transmission spectra of both can be adjusted to produce an optical filter with desired optical characteristics, allowing for greater freedom in designing the optical filter.

[0097] When the material of the transparent dielectric substrate 20 is a resin, the resin is, for example, a cyclic olefin resin such as a norbornene resin, a polyarylate resin, an acrylic resin, a modified acrylic resin, a polyimide resin, a polyetherimide resin, a polysulfone resin, a polyethersulfone resin, a polycarbonate resin, or a silicone resin.

[0098] Each of the optical filters 1a and 1b may be modified to further include other functional films, such as an infrared absorbing film, an infrared reflective film, and an anti-reflection film. Such functional films may be provided on the light absorbing film 10 or the transparent dielectric substrate 20. For example, the optical filter may include an anti-reflection film to increase the transmittance of a predetermined wavelength range (e.g., the visible light range). The anti-reflection film may be configured as a layer of a low-refractive index material such as MgF2 and SiO2, or as a laminate of a layer of such a low-refractive index material and a layer of a high-refractive index material such as TiO2, or as a dielectric multilayer film. Such anti-reflection films may be formed by methods involving physical reactions, such as vacuum deposition and sputtering, or by methods involving chemical reactions, such as CVD and sol-gel processes.

[0099] The optical filter may be configured, for example, by disposing the light-absorbing film 10 between two sheets of glass. In this case, the light-absorbing film 10 acts as a so-called intermediate film. This improves the rigidity and mechanical strength of the optical filter. In addition, the main surface of the optical filter becomes hard, which is advantageous from the standpoint of scratch prevention, etc. This advantage is particularly important when a relatively flexible resin is used as the binder or matrix in the light-absorbing film 10.

[0100] By providing an antireflection film on the surface of the light-absorbing film and optical filter obtained by curing the light-absorbing composition, an optical filter with even better optical properties can be provided. For example, as shown in FIG. 2B, an optical filter 1c can be provided that includes a light-absorbing film 10 and an antireflection film 30. In an optical filter having an antireflection film formed thereon, when light is incident on the optical filter at a predetermined angle of incidence, the amount of light reflected from the optical filter is reduced, approaching zero. This is extremely advantageous in an imaging device equipped with an optical filter having an antireflection film formed thereon, from the perspective of preventing ghosts, flare, and noise caused by multiple scattering of reflected light within the imaging device or camera module, for example.

[0101] The material of the anti-reflection film is not limited to a specific material. The method for forming the anti-reflection film is not limited to a specific method. The method for forming the anti-reflection film may be a gas phase method or a liquid phase method. For example, the method for forming the anti-reflection film may be a vapor deposition method. The method for forming the anti-reflection film may be a sol-gel method using a reactive material containing silicon, which is a liquid phase method that is excellent for forming anti-reflection films.

[0102] Antireflective coatings can be single-layer films made of the same material or multilayer films made of two or more different materials. The materials constituting each layer of the film and multilayer film are not limited to specific materials. Examples of such materials include inorganic compounds such as SiO2, TiO2, Ta2O3, MgF2, Al2O3, CaF2, ZrO2, CeO2, and ZnS. For example, when an antireflective coating or a layer contained in an antireflective coating contains SiO2, the film or layer may be formed by the so-called sol-gel method using an alkoxysilane compound as the starting material. The sol-gel method involves hydrolysis of the alkoxysilane compound in the presence of water and a catalyst, followed by condensation polymerization, resulting in a dense, hard film containing SiO2. The sol-gel method has the advantage of being able to form a film or layer containing SiO2 without requiring high temperatures.

[0103] When forming an anti-reflective coating using the sol-gel method, the starting material is not limited to a specific material, and the functional groups contained in the starting material are also not limited to a specific functional group. The starting material preferably includes a "trifunctional silane containing an alkyl group" such as MTES (methyltriethoxysilane) and TEOS (tetraethoxysilane), and a "tetrafunctional silane." Tetrafunctional silanes are essential for forming a film or layer with a strong and dense skeleton. However, using tetrafunctional silanes alone makes it difficult to control the reactivity and adjust the polarity of the film or layer. In addition, cracks are likely to occur in the film or layer. When the starting material contains a trifunctional silane in addition to a tetrafunctional silane, the flexibility of the silica skeleton is improved, making it easier to adjust the polarity of the film or layer and reducing cracking in the film or layer. Easily adjusting the polarity of the film or layer is desirable from the perspective of adjusting the refractive index of the anti-reflective coating. The organic functional groups in the trifunctional silane are not inherently limited to a specific functional group. In particular, trifunctional silanes having methyl groups as organic functional groups are desirable in order to form homogeneous liquids and coating films when combined with tetrafunctional silanes.

[0104] In the starting material, the ratio of the amount of "trifunctional silane containing an alkyl group" to the amount of "tetrafunctional silane" is not limited to a specific value. Desirably, in the starting material, the relationship of the amount of "trifunctional silane containing an alkyl group" to the amount of "tetrafunctional silane" is satisfied, based on mass, from 5:1 to 1:3. This facilitates the suppression of cracks in the antireflective coating, and facilitates the formation of a strong skeleton by the tetrafunctional silane. The starting material may contain components other than those involved in the sol-gel process. For example, the starting material may contain fine particles and a filler for adjusting the refractive index. In this case, the fine particles and the filler may be hollow or may be a high refractive index material. The starting material may contain a component that decomposes at a low temperature. This facilitates the adjustment of the refractive index of the antireflective coating. The temperature at which the coating is baked in the sol-gel process is not limited to a specific temperature. The temperature is, for example, in the range of 60°C to 250°C, preferably in the range of 70°C to 230°C, and more preferably in the range of 80°C to 200°C.

[0105] When the antireflective coating is a single-layer film, it is desirable that the material of the single-layer film have a low refractive index. The refractive index n1 of the antireflective coating material tends to be lowest when n1 = √n0. n0 is the refractive index of the substrate on which the antireflective coating is formed. For example, when the antireflective coating contains hollow particles formed from metal oxides such as SiO2 and TiO2 or organic materials such as PMMA, the interior of the hollow particles is occupied by air, which has a refractive index of approximately 1, thereby lowering the effective refractive index of the particles and tending to lower the refractive index of the antireflective coating. The dielectric constant and refractive index of a mixture consisting of multiple phases can be calculated using the effective medium approximation method using the Bruggemann equation. If the refractive index required for the antireflective coating is not too low, the antireflective coating may contain solid particles formed from the above materials. If the antireflective coating requires mechanical strength such as scratch resistance, it is advantageous for the antireflective coating to contain such solid particles. A film containing such hollow or solid particles may be formed by a sol-gel method. In particular, when hollow or solid particles made of SiO2 are used, there is a good affinity between the SiO2 in the film formed by the sol-gel method and the hollow or solid particles, which is expected to suppress aggregation of the hollow or solid particles and to suppress bleed-out, etc.

[0106] The antireflection coating may have a multilayer structure including a layer containing SiO formed by a sol-gel method and a layer formed by, for example, vacuum deposition, sol-gel, or other methods. For example, by forming the antireflection coating into a multilayer structure using two or more materials with different refractive indices, the wavelength band in which the antireflection effect is obtained is likely to be relatively wide, and the minimum reflectance value in the optical filter is likely to be low. When the antireflection coating is combined with a layer containing SiO formed by a sol-gel method to form a multilayer structure, the combined layer may be, for example, a layer containing hollow particles and containing SiO formed by a sol-gel method, a layer made of a material with a relatively high refractive index such as TiO or TaO, or a layer made of another material such as MgF.

[0107] The present invention will be described in more detail with reference to examples. Note that the present invention is not limited to the following examples. First, the evaluation method of the optical filters according to each example and each comparative example will be described.

[0108] <Measurement of Transmission Spectrum and Reflection Spectrum> The transmission spectrum and reflection spectrum of each optical filter at a predetermined angle of incidence were measured using an ultraviolet-visible-near-infrared spectrophotometer (manufactured by JASCO Corporation, product name: V-670).

[0109] <Thickness Measurement> The distance to the surface of each optical filter was measured using a laser displacement meter (manufactured by Keyence Corporation, product name: LK-H008), and the thickness of the light-absorbing film was measured by subtracting the thickness of the transparent glass substrate.

[0110] <Abrasion Resistance Test> An alcohol-soaked wiper was obtained by soaking a Kuraray Co., Ltd. Kuraclean Wiper LF-8G with ethanol, propylene glycol monomethyl ether (PGME), or propylene glycol monomethyl ether acetate (PGMEA). This alcohol-soaked wiper was applied to the light-absorbing film obtained in each Example and Comparative Example at a rate of 40 to 60 g / cm. 2 The surface of the light-absorbing film was rubbed by moving the scrubber back and forth 10 times over a length of about 3 cm while being pressed against the film with a pressure of 1000 psi. Thereafter, the condition of the surface of the light-absorbing film was visually confirmed, and a case where there was no particular change was evaluated as "A", a case where scratches were observed on the surface was evaluated as "B", and a case where peeling of the light-absorbing film occurred was evaluated as "C". The results are shown in Table 8.

[0111] <Ultraviolet Absorbing Compound> The following ultraviolet absorbing compounds were used in the production of the optical filters according to the examples and comparative examples.

[0112]

[0113] The structural formulas of the ultraviolet absorbing compounds (1-1) and (1-2) are represented by the following formulas (C) and (D), respectively.

[0114]

[0115]

[0116] <Compounds Containing Metal Components> The following materials containing metal components were used in the production of the optical filters according to the examples and comparative examples.

[0117]

[0118] Example 1 5.0 g of the ultraviolet absorber (1-1) shown in Table 1, 80.0 g of cyclohexanone as a solvent, and polyvinyl butyral (PVB) S-LEC KS-10 (molecular weight 1.7×10) manufactured by Sekisui Chemical Co., Ltd. were mixed together. 4 8.0 g of a hydroxyl group content (25 mol%) of 1,2-dimethyl-2,3-trimethyl-1,2,3-trimethyl ...

[0119] The light-absorbing composition according to Example 1 was spin-coated at 500 rotations per minute (rpm) onto one main surface of a transparent glass substrate (manufactured by SCHOTT, product name: D263T eco) made of borosilicate glass and measuring 76 mm x 76 mm x 0.21 mm, to form a coating film. The resulting coating film was thoroughly dried at room temperature and then placed in an oven and heat-treated at 140°C for 1 hour and then at 160°C for 2 hours to induce a crosslinking reaction between the PVB and TDI, thereby obtaining the light-absorbing film according to Example 1. In this manner, an optical filter including the light-absorbing film according to Example 1 was fabricated. FIG. 3 shows the transmission spectrum of the optical filter according to Example 1. FIG. 8 shows the reflection spectrum of the optical filter according to Example 1. Values ​​related to the film thickness and optical properties of the light-absorbing film of the optical filter according to Example 1 are shown in Tables 5, 6, and 7. The results of a scratch resistance test of the light-absorbing film according to Example 1 are shown in Table 8. FIG. 13 shows the transmission spectrum of the transparent glass substrate at an incident angle of 0 degrees.

[0120] Examples 2 to 4 Light-absorbing compositions according to Examples 2 to 4 were prepared in the same manner as in Example 1, except that the amount of isocyanate added and / or the type of PVB was changed as shown in Table 3. Light-absorbing films and optical filters according to Examples 2 to 4 were produced in the same manner as in Example 1, except that the light-absorbing compositions according to Examples 2 to 4 were used instead of the light-absorbing composition according to Example 1. The PVB used in Example 4 was S-LEC KS-1 (molecular weight 2.7×10) manufactured by Sekisui Chemical Co., Ltd. 4 , degree of acetalization 74 mol%, and hydroxyl group content 25 mol%). Values ​​related to the optical properties that can be seen from the transmission spectra and reflection spectra of the optical filters according to Examples 2 to 4 are shown in Tables 5, 6, and 7. From these results, it can be seen that good optical properties can be obtained even if the ratio of the mass of isocyanate to the mass of PVB in the light-absorbing composition varies within the range of 0.18 to 1.50. The results of the scratch resistance test of the light-absorbing films according to Examples 2 to 4 are shown in Table 8.

[0121] Examples 5 and 6 Light-absorbing compositions according to Examples 5 and 6 were prepared in the same manner as in Example 1, except that the type of PVB and the type and amount of isocyanate added were changed as shown in Table 3. Light-absorbing films and optical filters according to Examples 5 and 6 were produced in the same manner as in Example 1, except that the light-absorbing compositions according to Examples 5 and 6 were used instead of the light-absorbing composition according to Example 1. The PVB used in Example 5 was S-LEC BX-L (molecular weight 1.8×10) manufactured by Sekisui Chemical Co., Ltd. 4 The PVB used in Example 6 was S-LEC BX-1 (molecular weight 10 × 10) manufactured by Sekisui Chemical Co., Ltd. 4, degree of acetalization 72 mol%, and hydroxyl group content 27 mol%. The isocyanate used in Example 5 was diphenylmethane diisocyanate (MDI), and the isocyanate used in Example 6 was hexamethylene diisocyanate (HDI). FIG. 4 shows the transmission spectrum of the optical filter according to Example 5. FIG. 9 shows the reflection spectrum of the optical filter according to Example 5. Values ​​related to the optical properties of the optical filters according to Examples 5 and 6 are shown in Tables 5, 6, and 7. Examples 5 and 6 demonstrate that good optical properties can be obtained even when MDI or HDI is used instead of TDI. Table 8 shows the results of a scratch resistance test of the light-absorbing films according to Examples 5 and 6.

[0122] Examples 7 to 14 Light-absorbing compositions according to Examples 7 to 14 were prepared in the same manner as in Example 1, except that the type or amount of the ultraviolet absorbing compound, material containing a metal component, PVB, or isocyanate was changed as shown in Table 3. Light-absorbing films and optical filters according to Examples 7 to 14 were produced in the same manner as in Example 1, except that the light-absorbing compositions according to Examples 7 to 14 were used instead of the light-absorbing composition according to Example 1. The PVB used in Example 7 was S-LEC BX-1 manufactured by Sekisui Chemical Co., Ltd. The PVB used in Example 8 was S-LEC KS-1 manufactured by Sekisui Chemical Co., Ltd. The PVB used in Example 12 was S-LEC BL-S (molecular weight 2.3 × 10) manufactured by Sekisui Chemical Co., Ltd. 4 The PVB used in Example 13 was S-LEC BL-1 (molecular weight 1.9×10) manufactured by Sekisui Chemical Co., Ltd. 4 , degree of acetalization 63 mol%, and hydroxyl group content 36 mol%). In Examples 9, 10, 11, and 14, S-LEC KS-10 manufactured by Sekisui Chemical Co., Ltd. was used as the PVB. Figures 5, 6, and 7 show the transmission spectra of the optical filters according to Examples 7, 9, and 11, respectively. Figures 10, 11, and 12 show the reflection spectra of the optical filters according to Examples 7, 9, and 11, respectively. Furthermore, values ​​related to the optical properties of the optical filters according to Examples 7 to 14 are shown in Tables 5, 6, and 7. The results of the scratch resistance test of the light-absorbing films according to Examples 7 to 14 are shown in Table 8.

[0123] <Comparative Example 1> A light-absorbing composition according to Comparative Example 1 was prepared in the same manner as in Example 1, except that no isocyanate was added. A light-absorbing film and optical filter according to Comparative Example 1 were produced in the same manner as in Example 1, except that the light-absorbing composition according to Comparative Example 1 was used instead of the light-absorbing composition according to Example 1. Values ​​related to the optical properties of the optical filter according to Comparative Example 1 are shown in Tables 5, 6, and 7. The results of the scratch resistance test of the light-absorbing film according to Comparative Example 1 are shown in Table 8.

[0124] The optical filters according to each Example and Comparative Example 1 had good optical properties in terms of reproducing human visual sensitivity. On the other hand, a comparison between the Examples and Comparative Examples suggested that good solvent resistance and scratch resistance are easily obtained when the light-absorbing composition contains both PVB and isocyanate. In particular, it was suggested that good solvent resistance and scratch resistance are easily obtained when the ratio of the mass of isocyanate to the mass of PVB in the light-absorbing composition is 0.15 or more. From the viewpoint of good solvent resistance and scratch resistance, the ratio of the mass of isocyanate to the mass of PVB is considered to be desirably 0.15 or more, and more desirably 0.18 or more. The upper limit of the ratio of the mass of isocyanate to the mass of PVB is not considered to be limited to a specific value, but from the viewpoint of preventing the light-absorbing composition from curing immediately after application of the light-absorbing composition due to an increase in the isocyanate, and facilitating the formation of a light-absorbing film with a flat and uniform thickness, it is considered desirable for the ratio to be 1.50 or less. From the viewpoint of good optical properties, solvent resistance, and scratch resistance, it was suggested that the ratio of the mass of isocyanate to the mass of the ultraviolet absorbing compound is preferably 0.3 or more, and more preferably in the range of 0.3 to 2.4.

[0125]

[0126]

[0127]

[0128]

[0129]

[0130]

Claims

1. UV-absorbing compounds having hydroxyl groups and carbonyl groups in their molecules, Metal components, Polyvinyl butyral and It contains isocyanates, At least a portion of the aforementioned metal component is bonded to an organic oxy group. Light-absorbing composition.

2. The content of the metal component in the light-absorbing composition is 0.005% to 2% by mass. The light-absorbing composition according to claim 1.

3. The content of the ultraviolet-absorbing compound in the light-absorbing composition is 0.1% to 20% by mass. The light-absorbing composition according to claim 1 or 2.

4. The ratio of the mass of the ultraviolet-absorbing compound to the mass of the metal component is 5 to 300. The light-absorbing composition according to claim 1 or 2.

5. The ratio of the mass of the isocyanate to the mass of the polyvinyl butyral is 0.05 to 3.

0. The light-absorbing composition according to claim 1 or 2.

6. The ratio of the mass of the isocyanate to the mass of the ultraviolet-absorbing compound is 0.1 to 3.

0. The light-absorbing composition according to claim 1 or 2.

7. The hydroxyl group and the carbonyl group are separated by 1 to 3 atoms. The light-absorbing composition according to claim 1 or 2.

8. The aforementioned ultraviolet-absorbing compound includes a benzophenone compound represented by the following formula (A1): The light-absorbing composition according to claim 1 or 2. 【Chemistry 1】 In formula (A1), R 11 , R 12 , R 21 , and R 22 are each independently a hydrogen atom, a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, a heterocyclic group having 5 to 10 ring atoms, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an amino group, a nitro group, a cyano group, a sulfonyl group having 1 to 6 carbon atoms, or a sulfinyl group having 1 to 6 carbon atoms, and at least one of them is a hydroxy group. In formula (A1), when R 11 , R 12 , R 21 , or R 22 is a functional group other than a hydroxy group, a plurality of R 11 , a plurality of R 12 , a plurality of R 21 , or a plurality of R 22 may be present, and at least one of R 11 , R 12 , R 21 , and R 22 may not be present.

9. The aforementioned ultraviolet-absorbing compound includes a benzophenone compound represented by the following formula (A2): The light-absorbing composition according to claim 1 or 2. 【Chemistry 2】 [In formula (A2), R 31 R is a hydrogen atom, a hydroxyl group, a carboxyl group, an aldehyde group, a halogen atom, a group having a halogen atom, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. In formula (A2), R 41 and R 42 R may be a hydroxyl group, a carboxyl group, an aldehyde group, a group having a halogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. 41 and R 42 It does not have to exist. In formula (A2), multiple R 41 There may be multiple R 42 It may exist.

10. The aforementioned metal component includes at least one selected from the group consisting of Li, Na, Mg, Ca, Sr, Ba, Ge, Sn, Pb, Al, Ga, In, Tl, Zn, Cd, Cu, Ag, Au, Ni, Pd, Pt, Co, Rh, Ir, Fe, Mn, Cr, Mo, W, V, Nb, Ta, Ti, and Zr. The light-absorbing composition according to claim 1 or 2.

11. An organic solvent, an ultraviolet-absorbing compound having a hydroxyl group and a carbonyl group in its molecule, This involves adding and mixing a compound containing a metal component, polyvinyl butyral, and isocyanate. A method for producing the light-absorbing composition according to claim 1 or 2.

12. UV-absorbing compounds having hydroxyl groups and carbonyl groups in their molecules, Metal components, A resin having urethane bonds, and containing At least a portion of the aforementioned metal component is bonded to an organic oxy group. Light-absorbing film.

13. The ratio of the mass of the ultraviolet-absorbing compound to the mass of the metal component is 5 to 300. The light-absorbing film according to claim 12.

14. The urethane bond is formed between a first site derived from polyvinyl butyral and a second site derived from isocyanate. The ratio of the mass of the isocyanate and the second part to the mass of the polyvinyl butyral and the first part is 0.05 to 3.

0. The light-absorbing film according to claim 12 or 13.

15. The urethane bond is formed between a first site derived from polyvinyl butyral and a second site derived from isocyanate. The ratio of the mass of the isocyanate and the second site to the mass of the ultraviolet-absorbing compound is 0.1 to 3.

0. The light-absorbing film according to claim 12 or 13.

16. The hydroxyl group and the carbonyl group are separated by 1 to 3 atoms. The light-absorbing film according to claim 12 or 13.

17. In the transmission spectrum at an incident angle of 0 degrees, the transmittance T at a wavelength of 400 nm is shown. 400 It is less than 5%. The light-absorbing film according to claim 12 or 13.

18. The aforementioned ultraviolet-absorbing compound includes a benzophenone compound represented by the following formula (A1): The light-absorbing film according to claim 12 or 13. 【Transformation 3】 [In formula (A1), R 11 , R 12 , R 21 , and R 22 At least one of them is a hydroxyl group. In formula (A1), R 11 , R 12 , R 21 , or R 22 If the functional group is not a hydroxyl group, then multiple R 11 , multiple R 12 , multiple R 21 , or multiple R 22 It is possible that R exists. 11 , R 12 , R 21 , and R 22 At least one of these may not be present.

19. The aforementioned ultraviolet-absorbing compound includes a benzophenone compound represented by the following formula (A2): The light-absorbing film according to claim 12 or 13. 【Chemistry 4】 [In formula (A2), R 31 R is a hydrogen atom, a hydroxyl group, a carboxyl group, an aldehyde group, a halogen atom, a group having a halogen atom, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. In formula (A2), R 41 and R 42 R may be a hydroxyl group, a carboxyl group, an aldehyde group, a group having a halogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. 41 and R 42 It does not have to exist. In formula (A2), multiple R 41 There may be multiple R 42 It may exist.

20. The transmission spectrum obtained by incidenting light in the wavelength range of 300 nm to 1200 nm onto the light-absorbing film at an incident angle of 0° satisfies the following requirements: (ia), (ii-a), (iii-a), (iv-a), (va), and (vi-a). The light-absorbing film according to claim 12 or 13. (ia) The maximum transmittance in the wavelength range of 300 nm to 380 nm is 3% or less. (ii-a) The transmittance at a wavelength of 400 nm is 5% or less. (iii-a) The transmittance at a wavelength of 410 nm is 10% or less. (iv-a) The wavelength λ in the range of 350 nm to 500 nm at which the transmittance is 50% UV It exists within the range of 405 nm to 490 nm. (va) The minimum transmittance in the wavelength range of 480 to 600 nm is 85% or higher. (vi-a) Wavelength (λ UV -10) Transmittance at wavelength (λ UV The ratio of transmittance at +10 nm is 1.8 or higher.

21. An optical filter comprising the light-absorbing film described in claim 12 or 13.

22. A method for manufacturing an optical filter including a light-absorbing film according to claim 12 or 13, The manufacturing method described above is a method for manufacturing an optical filter, comprising the steps described in either (i) or (ii) below. (i) Forming the light-absorbing film on an image sensor or optical component. (ii) Forming the light-absorbing film on a substrate and peeling the light-absorbing film from the substrate.

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