Light-absorbing composition, light absorber, light filter, ambient light sensor, imaging device, method for producing light-absorbing composition, and method for producing light absorber

Abstract

The light-absorbing composition contains a silicon-containing compound [alpha] and a light-absorbing compound. The silicon-containing compound (alpha) is at least one compound selected from the group consisting of an alkoxysilane containing a group (alpha-1) having 10 or more carbon atoms and a hydrolysate of the alkoxysilane.

Description

Technical Field

[0001] The present invention relates to a light-absorbing composition, a light absorber, an optical filter, an ambient light sensor, an imaging device, a method for producing the light-absorbing composition, and a method for producing the light absorber. Background Art

[0002] In an imaging device or an ambient light sensor using a solid-state imaging element such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), various filters are arranged in front of the solid-state imaging element. For example, in an imaging device, a filter can be used to obtain an image with good color reproducibility. In an ambient light sensor, a filter can be used to adjust the sensing of ambient light.

[0003] Generally speaking, solid-state imaging elements have sensitivity in a wide wavelength range from the ultraviolet region to the infrared region. On the other hand, human visual sensitivity only exists in the so-called visible light region of about 380nm to 780nm. Therefore, in order to make the spectral sensitivity of the solid-state imaging element in the imaging device close to the visual sensitivity of humans, it is known to configure a filter in front of the solid-state imaging element to block part of the infrared or ultraviolet light.

[0004] Among them, light-absorbing filters having a film or layer containing a light absorber have attracted attention. The transmittance characteristics of the filter having a film containing a light absorber are not easily affected by the incident angle. Therefore, for example, in an imaging device, even when light is incident on the filter at an angle, a good image with little change in color tone, little color unevenness within the surface, and good reproducibility can be obtained. In addition, the light-absorbing filter does not use a light-reflecting film, so it is possible to suppress the generation of ghosting or light spots caused by multiple reflections caused by light reflection, and it is easy to obtain a good image. In addition, the filter having a film containing a light absorber is also advantageous from the perspective of miniaturization and thinning of the imaging device.

[0005] For example, Patent Document 1 describes an optical filter having a light absorbing layer containing copper phosphite and an organic dye and having a thickness of 80 μm or less. The maximum transmittance of the light absorbing layer of the optical filter is 5% or less within a wavelength range of 750 nm to 1080 nm.

[0006] Patent Document 2 describes an optical filter having a light absorbing layer containing a light absorber composed of a predetermined phosphonic acid and copper ions and not containing a predetermined phosphate ester. Patent Document 2 states that the predetermined phosphate ester is easily hydrolyzed and is not the best material from the perspective of weather resistance.

[0007] Patent Document 3 describes an optical filter having a UV-IR absorbing layer, the UV-IR absorbing layer comprising a UV-IR absorber formed of at least one of phosphonic acid and sulfonic acid and copper ions capable of absorbing ultraviolet and infrared rays. The optical filter has a haze of 5% or less. Patent Document 3 describes that by incorporating an optical filter including such a UV-IR absorbing layer into an imaging device, a high-quality image can be obtained.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: International Publication No. 2020 / 071461

[0011] Patent Document 2: International Publication No. 2019 / 093076

[0012] Patent Document 3: International Publication No. 2019 / 208518 Summary of the invention

[0013] Problems to be solved by the invention

[0014] The techniques described in Patent Documents 1 to 3 have room for further study from the perspective of thinness and optical properties. Therefore, the present invention provides a light absorbing compound that is advantageous from the perspective of thinness and optical properties. In addition, the present invention provides a light absorber that is advantageous from the perspective of thinness and optical properties.

[0015] Means for solving problems

[0016] The present invention provides a light absorbing composition comprising:

[0017] At least one selected from the group consisting of an alkoxysilane containing a group having 10 or more carbon atoms, a hydrolyzate of the alkoxysilane, and a polymer of the hydrolyzate of the alkoxysilane; and

[0018] Light absorbing compounds.

[0019] In addition, the present invention provides a light absorber having an average value T A 460-600 More than 80%,

[0020] The above average value T A 460-600 is the average value of the transmittance in the wavelength range of 460 nm to 600 nm of the transmission spectrum obtained by making light incident on the above-mentioned light absorber at an incident angle of 0°,

[0021] The value obtained by dividing the optical density OD of the light absorber at the wavelength λ by the thickness of the light absorber is expressed as η. λ [μm -1 ], satisfying 0.009≤η 380 and 0.008≤η 750 conditions.

[0022] Furthermore, the present invention provides an optical filter including the above-mentioned light absorber.

[0023] In addition, the present invention provides an ambient light sensor including the above-mentioned light absorber.

[0024] Furthermore, the present invention provides an imaging device including the above-mentioned light absorber.

[0025] In addition, the present invention provides a method for producing a light-absorbing composition, comprising:

[0026] preparing a light absorbing compound dispersion liquid in which a light absorbing compound including phosphonic acid and copper components is dispersed in a solvent;

[0027] mixing the light absorbing compound dispersion and an alkoxysilane containing a group having 10 or more carbon atoms or a hydrolyzate of the alkoxysilane; and

[0028] A portion of the solvent is removed from the light-absorbing compound dispersion.

[0029] In addition, the present invention provides a method for producing a light absorber, comprising: curing a light absorbing composition applied to a surface of a substrate to obtain a light absorber,

[0030] The light absorbing composition comprises:

[0031] a light absorbing compound comprising a phosphonic acid and a copper component; and

[0032] at least one selected from the group consisting of an alkoxysilane containing a group having 10 or more carbon atoms, a hydrolyzate of the alkoxysilane, and a polymer of the hydrolyzate of the alkoxysilane,

[0033] The light absorber has a thickness of 150 μm or less.

[0034] In addition, the present invention provides an optical filter comprising:

[0035] a light absorber; and

[0036] an antireflection film provided on the surface of the light absorber,

[0037] The above-mentioned optical filter satisfies the following conditions (I) and (II).

[0038] (I) The value obtained by dividing the optical density OD at wavelength λ by the thickness of the above-mentioned light absorber is expressed as η 2-λ [μm -1 ], 0.009≤η 2-380 and 0.008≤η 2-750 ,

[0039] (II) The average value of the transmittance in the wavelength range of 460 nm to 600 nm is represented as T2 A 460-600 When 90%≤T2 A 460-600 .

[0040] Effects of the Invention

[0041] The above-mentioned light-absorbing composition and light absorber are advantageous in terms of thinness and optical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1A This is a cross-sectional view showing an example of the optical filter of the present invention.

[0043] Figure 1B This is a cross-sectional view showing another example of the optical filter of the present invention.

[0044] Figure 1C This is a cross-sectional view showing still another example of the optical filter of the present invention.

[0045] Figure 1D This is a cross-sectional view showing still another example of the optical filter of the present invention.

[0046] Figure 2 This is a graph showing a transmission spectrum of an example of glass included in a substrate.

[0047] Figure 3A It is a cross-sectional view showing an example of the ambient light sensor of the present invention.

[0048] Figure 3B This is a cross-sectional view showing an example of the photoelectric conversion element of the present invention.

[0049] Figure 4A This is a diagram showing an example of an imaging device according to the present invention.

[0050] Figure 4B This is a diagram showing another example of the imaging device of the present invention.

[0051] Figure 5A Graph showing the transmission spectrum of the light absorber of Example 1.

[0052] Figure 5B : is a graph showing the reflection spectrum of the light absorber of Example 1.

[0053] Fig. 6A Graph showing the transmission spectrum of the light absorber of Example 2.

[0054] Figure 6B Graph showing the reflection spectrum of the light absorber of Example 2.

[0055] Fig. 7A Graph showing the transmission spectrum of the light absorber of Example 3.

[0056] Figure 7B Graph showing the reflection spectrum of the light absorber of Example 3.

[0057] Figure 8 Graph showing the transmission spectrum of the light absorber of Example 8.

[0058] Fig. 9 3 is a graph showing the transmission spectrum of the light absorber of Example 13.

[0059] Fig.10 : is a graph showing the transmission spectrum of the light absorber of Example 14.

[0060] Fig.11A 3 is a graph showing the transmission spectrum of the substrate of Example 16.

[0061] Fig. 11B : is a graph showing the transmission spectrum of the optical filter of Example 16.

[0062] Fig.12 3 is a graph showing the transmission spectrum of the optical filter of Comparative Example 3.

[0063] Fig.13 : is a graph showing the transmission spectrum of the optical filter of Example 17.

[0064] Fig.14 : is a graph showing the transmission spectrum of the optical filter of Example 18. DETAILED DESCRIPTION

[0065] Due to the global popularity of information terminals such as smartphones equipped with camera modules, the demand for thinner filters installed in cameras or ambient light sensors is increasing. The filter described in Patent Document 1 has a thickness of less than 80 μm and a transmittance of less than 5% within a wavelength of 750 nm to 1080 nm, but it is difficult to say that the light absorption characteristics within this wavelength range are sufficient. For example, it can be understood that it is difficult to achieve a transmittance of less than 1% within a wavelength of 750 nm to 1080 nm with a thickness of about 110 μm. In other words, it can be understood that in a filter having a light absorption layer containing copper phosphate and an organic pigment, even if an organic pigment is used in combination, it is difficult to achieve sufficient light absorption performance with a thickness of about 110 μm.

[0066] The optical filter described in Patent Document 2 is promising in that it does not contain phosphate ester, but it is difficult to say that it has sufficient properties in terms of both thinness and desired optical properties. In addition, by not containing phosphate ester, there is a possibility that part of the copper phosphonate will aggregate and reduce the transmittance in the visible light region.

[0067] Patent Document 3 describes the content of copper components contained in the light absorbing compound and the viscosity of the liquid light absorbing composition as a precursor of the UV-IR absorbing layer. The minimum haze value of the UV-IR absorbing layer described in Patent Document 1 is 0.2%. If a haze value of less than 0.2% can be achieved in a light absorbing filter, the value of the filter can be further improved.

[0068] The inventors of the present invention have conducted repeated and intensive studies, and as a result, have newly discovered a light-absorbing compound that is advantageous in achieving desired optical properties such as transmittance close to the visual sensitivity curve of humans and low haze even when thin. In addition, a novel light absorber that is advantageous in achieving desired optical properties such as transmittance close to the visual sensitivity curve of humans and low haze has been completed.

[0069] Hereinafter, embodiments of the present invention will be described. It should be noted that the following description is for illustration of the present invention, and the present invention is not limited to the following embodiments.

[0070] The light-absorbing composition comprises a silicon-containing compound α and a light-absorbing compound. The silicon-containing compound α is at least one selected from the group consisting of an alkoxysilane containing a group α-1 having more than 10 carbon atoms, a hydrolyzate of the alkoxysilane, and a polymer of the hydrolyzate of the alkoxysilane. The hydrolyzate of the alkoxysilane is a silicon compound having a silanol group (-Si-OH) produced by the hydrolysis of the alkoxysilane. The polymer of the hydrolyzate of the alkoxysilane is a compound containing a siloxane bond (-O-Si-O-) by condensation of a part of the hydrolyzate. It is believed that due to the presence of the silicon-containing compound α, the group α-1 is likely to become a steric hindrance in the aggregation of the light-absorbing compound. Therefore, for example, when a light-absorbing compound having a structure containing a complex is formed, it is easy to prevent the generation of aggregates of the light-absorbing compound. As a result, the light-absorbing compound is homogeneously dispersed in the light-absorbing composition, and it is easy to achieve the desired optical properties such as a transmission spectrum corresponding to the human visual sensitivity curve and low haze in the light absorber made using the light-absorbing composition. The alkoxysilane containing the group α-1 is represented by the following formula (1), for example. In the formula (1), n ​​is 1, 2 or 3, and R 11 is a group containing at least a carbon atom (C) and a hydrogen atom (H), R 11 At least one of them is a group α-1 having 10 or more carbon atoms.12 is a group containing at least carbon atoms (C) and hydrogen atoms (H), which can be combined with R 11 Same as R 11 different.

[0071] R 11 4-n Si(OR 12 ) n Formula (1)

[0072] The light absorbing compound is not limited to a specific compound. The light absorbing compound may be, for example, a compound containing phosphonic acid and a copper component, a compound containing a phosphate ester and a copper component, or a compound containing other phosphoric acid compounds and a copper component. Examples of other phosphoric acid compounds are phosphoric acid, phosphorous acid, and hypophosphorous acid. The compound containing phosphoric acid may be composed of M x Cu y PO z (M may not exist, or represent a metal element other than Cu, x, y, and z are real numbers) represents a phosphoric acid-copper complex. In addition, when a light-absorbing compound containing a phosphoric acid compound such as a phosphonic acid, a phosphate ester or phosphoric acid and a copper component is generated, a part of an anion of a compound that is a raw material of a copper component, especially a copper ion, may be contained in the light-absorbing compound. For example, when the raw material of the copper component is copper acetate, a part of the component of acetic acid may be contained in the light-absorbing compound, and when the raw material of the copper component is copper benzoate, a part of the component of benzoic acid may be contained in the light-absorbing compound. The fact that the light-absorbing compound contains a phosphoric acid compound such as a phosphonic acid, a phosphate ester or phosphoric acid and a copper component does not prevent it from containing compounds or elements other than these. The light-absorbing compound may be a compound containing a sulfonic acid and a copper component, may be a metal oxide, or may be an organic pigment. Examples of metal oxides are tungsten oxide, indium tin oxide (ITO), and antimony tin oxide. Examples of organic pigments are diimmonium compounds, cyanine compounds, squarylium salt compounds, phthalocyanine compounds, and pyrrolopyrrole compounds.

[0073] The light-absorbing compound is preferably a compound containing phosphonic acid and a copper component, a compound containing a phosphate ester and a copper component, a compound containing phosphoric acid and a copper component, a compound containing a sulfonic acid and a copper component, or a compound formed in the form of a complex of these compounds. In this case, the light-absorbing compound tends to have a wide absorption band in the infrared region, and the light-absorbing composition is expected to be a material for a filter that shields light in a specified wavelength range only by absorption.

[0074] In the light-absorbing composition, the above-mentioned compounds may be used alone as the light-absorbing compound, or a plurality of compounds may be used in combination.

[0075] Phosphonic acid, phosphate ester and phosphoric acid are oxides containing a phosphorus atom (P) and an oxygen atom (O). They can coexist, for example, the light absorbing compound can exist in the form of a compound containing phosphonic acid, phosphate ester and a copper component. Even in the case where the light absorbing compound is a complex containing phosphonic acid and a copper component, a phosphate ester can be added as a dispersant. In this case, the light absorbing composition can contain a compound containing phosphonic acid, phosphate ester and a copper component. Copper (II) acetate or copper (II) benzoate can be the raw material of the copper component of the light absorbing compound. In this case, the acetic acid component (CH3COO - or CH3COOH) or benzoic acid component (C6H5COO - A portion of C6H5COOH) may be coordinated to copper ions or copper complexes containing phosphorus compounds such as phosphonic acid and copper components in these light absorbing compounds. Furthermore, the copper compound as a raw material of the copper component may be a hydrate, and the raw material may contain water molecules.

[0076] When the light absorbing compound includes phosphonic acid, the phosphonic acid is not limited to a specific phosphonic acid. The phosphonic acid is represented by the following formula (a), for example. In formula (a), R1 is an alkyl group or a haloalkyl group in which at least one hydrogen atom in the alkyl group is substituted by a halogen atom. In this case, the transmission band of the light absorber prepared using the light absorbing composition easily reaches a wavelength of about 700 nm, and the light absorber easily has the desired transmittance characteristics. The phosphonic acid represented by formula (a) is called an alkylphosphonic acid.

[0077] [Chemistry 1]

[0078]

[0079] Examples of alkylphosphonic acids are methylphosphonic acid, ethylphosphonic acid, n-(n-)propylphosphonic acid, isopropylphosphonic acid, n-(n-)butylphosphonic acid, isobutylphosphonic acid, sec-butylphosphonic acid, tert-butylphosphonic acid, hexylphosphonic acid, octylphosphonic acid or bromomethylphosphonic acid.

[0080] The light absorbing compound may contain a phosphonic acid represented by the following formula (b) as the phosphonic acid. In formula (b), R2 is an aryl group, a halogenated aryl group in which at least one hydrogen atom in the aryl group is replaced by a halogen atom, a group in which at least one hydrogen atom in the aryl group is replaced by a nitro group, or a group in which at least one hydrogen atom in the aryl group is replaced by a hydroxyl group. The aryl group is, for example, a phenyl group. The halogenated aryl group is, for example, a halogenated phenyl group. As a result, the light absorber prepared using the light absorbing composition is more likely to have the desired transmittance characteristics. The phosphonic acid represented by formula (b) is referred to as an aryl phosphonic acid.

[0081] [Chemistry 2]

[0082]

[0083] Examples of arylphosphonic acids are phenylphosphonic acid, bromophenylphosphonic acid, benzylphosphonic acid, fluorophenylphosphonic acid, iodophenylphosphonic acid, nitrophenylphosphonic acid, hydroxyphenylphosphonic acid, tolylphosphonic acid, xylylphosphonic acid and naphthylphosphonic acid.

[0084] The light absorbing compound may contain only alkylphosphonic acid, only arylphosphonic acid, or both alkylphosphonic acid and arylphosphonic acid as phosphonic acid. The light absorbing compound may contain one or more alkylphosphonic acids, and the light absorbing compound may contain one or more arylphosphonic acids. In the light absorbing compound, the alkylphosphonic acid and the arylphosphonic acid may be bonded to the copper component, respectively.

[0085] When the light absorbing compound includes a copper component, the copper component is a concept including copper ions, copper complexes, and compounds containing copper. The copper component can have good absorption characteristics for a portion of light belonging to the near-infrared region and high transmittance throughout the visible light region of 450nm to 680nm. For example, although detailed description is omitted, in the case of divalent copper ions Cu 2+ In the case of adopting a hexacoordinated complex structure, light with a wavelength of corresponding energy is absorbed in association with the electronic transition between d orbitals with different energy levels. In divalent copper ions, due to the absorption of light belonging to a relatively wide wavelength range of infrared rays, it is believed that the optical filter used in the field of digital photography plays a light absorption function with high utilization value. The width of the absorption band, the intensity of absorption, etc. depend to a great extent on the structure or property of the ligand coordinated with the copper ion. According to these circumstances, light absorbers or filters comprising compounds formed by phosphorus compounds such as phosphonic acid and phosphate coordinated to copper ions are preferably used for correction of visual sensitivity.

[0086] The supply source of the copper component contained in the light absorbing compound is not limited to a specific substance. Examples of the supply source of the copper component can be anhydrous or hydrated copper salts of organic acids such as copper acetate, copper benzoate, copper pyrophosphate and copper stearate, or mixtures thereof. Among them, copper acetate or copper benzoate is preferably used. In addition, these copper salts can be used alone, or multiple copper salts or mixtures thereof can be used.

[0087] The light absorbing composition may contain at least one silicon-containing compound β selected from the group consisting of an alkoxysilane represented by the following formula (2) and a hydrolyzate of the alkoxysilane. In the formula (2), m is an integer of 3 or 4, and R 01 and R 02 Can be the same or different, R 01 and R 02are groups containing at least a carbon atom (C) and a hydrogen atom (H), respectively. The alkoxysilane shown in formula (2) is a trifunctional alkoxysilane or a tetrafunctional alkoxysilane. In the light-absorbing composition, as the silicon-containing compound β, only a trifunctional alkoxysilane may be included, only a tetrafunctional alkoxysilane may be included, or both a trifunctional alkoxysilane and a tetrafunctional alkoxysilane may be included. The silicon-containing compound may be an alkoxysilane as a monomer, or a compound formed by hydrolysis of a portion of the alkoxysilane. The silicon-containing compound β may include a compound containing a siloxane bond by condensation of a portion of the hydrolyzate of the alkoxysilane.

[0088] R 01 4-m Si(OR 02 ) m Formula (2)

[0089] In the light-absorbing composition, by including the silicon-containing compound β shown in formula (2), a network is easily formed when the light-absorbing composition is cured. For example, when using the light-absorbing composition to manufacture a light absorber, a siloxane bond (-Si-O-Si-) is formed by treating it in a manner that fully causes the hydrolysis reaction and polycondensation reaction of the alkoxysilane. As a result, the light absorber is likely to have good moisture resistance. In addition, the light absorber has good heat resistance. The reason is that the bond energy of the siloxane bond is higher than that of bonds such as -CC- bonds and -CO- bonds, and it is chemically stable and has excellent heat resistance and moisture resistance. From the perspective of improving the compactness of the light absorber, the light-absorbing composition preferably includes a tetrafunctional alkoxysilane with m=4 in formula (2) as the silicon-containing compound β. R 01 and R 02 It may be a hydrocarbon group having 1 to 8 carbon atoms or a group containing an aryl group. In addition, by including a trifunctional alkoxysilane having m=3 in addition to the tetrafunctional alkoxysilane having m=4 in formula (2), flexibility of the light absorber can be enhanced.

[0090] As described above, in the light absorbing composition, as one of the silicon-containing compounds, a silicon-containing compound α is included. The group α-1 in the silicon-containing compound α is not limited to a specific group as long as it has 10 or more carbon atoms. The group α-1 may be an alkyl group, or a substituted alkyl group in which at least one hydrogen atom in the alkyl group is substituted with a halogen atom, a nitro group, or an amino group. In this case, the alkyl group and the substituted alkyl group may have a branched carbon chain or may not have a branched carbon chain.

[0091] The group α-1 may have a phenyl group or a substituted phenyl group in which at least one hydrogen atom in the phenyl group is substituted with a halogen atom, a nitro group or an amino group. The group α-1 may have a reactive functional group such as a vinyl group, an epoxy group, a carbonyl group, an ester group, an amino group, a nitrile group or a hydroxyl group.

[0092] The silicon-containing compound α may be a trifunctional alkoxysilane, a difunctional alkoxysilane, or a hydrolyzate of these alkoxysilanes. They can easily disperse the light-absorbing compound in a desired state in the light-absorbing composition, and can impart a predetermined flexibility and crosslinking property to the polymer generated by the hydrolysis and polycondensation of tetrafunctional alkoxysilanes such as tetraethoxysilane (TEOS). This is advantageous in terms of improving the mechanical strength of the light absorber obtained using the light-absorbing composition and improving weather resistance.

[0093] When the light absorbing composition contains trifunctional alkoxysilane, difunctional alkoxysilane, or a hydrolyzate of these alkoxysilanes as the silicon-containing compound α, the necessity of adding a dispersibility-imparting compound such as polyoxyalkyl phosphate to the light absorbing composition can be reduced.

[0094] In the light-absorbing composition, as the silicon-containing compound α, only at least one selected from the group consisting of trifunctional alkoxysilanes and hydrolyzates of trifunctional alkoxysilanes may be included. As the silicon-containing compound α, only at least one selected from the group consisting of difunctional alkoxysilanes and hydrolyzates of difunctional alkoxysilanes may be included. In the light-absorbing composition, difunctional alkoxysilanes, trifunctional alkoxysilanes, or hydrolyzates thereof may be included as the silicon-containing compound α together with the tetrafunctional alkoxysilane, trifunctional alkoxysilane, or hydrolyzates thereof represented by formula (2).

[0095] The light-absorbing composition may not contain a curable resin. This is because the silicon-containing compound α allows the light-absorbing compound to exist in a desired state and polymerizes in a manner that the light-absorbing composition is cured, or the silicon-containing compound β also functions as a network former and polymerizes in a manner that the light-absorbing composition is cured. When the light-absorbing composition contains a tetrafunctional alkoxysilane contained in the alkoxysilane represented by formula (2), it is expected that the density of the light absorber will be improved or the hardness will be improved. The alkoxysilane represented by formulas (1) and (2) can be cured by increasing its molecular weight by hydrolysis and condensation of siloxane bonds through the so-called sol-gel method. In addition, the solvent or by-product contained in the light-absorbing composition containing the alkoxysilane or its hydrolyzate is removed by evaporation, etc., so that the light-absorbing composition can be cured in the form of a dry gel. It is impossible to determine which effect is dominant, but it is believed that various effects and processes are included, including the dispersion effect of the light-absorbing compound.

[0096] The content of the silicon-containing compound α in the light-absorbing composition is not limited to a specific value. For example, when the light-absorbing compound contains a copper component, the ratio of the amount of silicon atoms contained in the silicon-containing compound α to the amount of the copper component is CSThe ratio r is 0.30 or more on a molar basis. In this case, it is more difficult to form aggregates of the light-absorbing compound in the light-absorbing composition. CS It is preferably 0.35 or more, and more preferably 0.40 or more. CS For example, it is 2.80 or less. In this case, the thickness of the light absorber obtained by using the light absorbing composition can be easily reduced, and it is easy to contribute to the reduction of the height of the element or device including the light absorber. CS It is preferably 2.50 or less, and more preferably 2.20 or less.

[0097] When the light-absorbing composition contains alkoxysilane, a humidification treatment can be performed when the light-absorbing composition is cured to produce a light absorber. In the humidification treatment, the light-absorbing composition is exposed to an atmosphere with high humidity. It is believed that through the humidification treatment, the moisture in the atmosphere promotes the hydrolysis of the alkoxysilane contained in the light-absorbing composition or the light absorber, which helps to form a siloxane bond. Through the humidification treatment, a hard and dense light absorber can be formed without agglomerating the particles containing the light-absorbing compound.

[0098] The alkoxysilane containing the group α-1 is not limited to a specific alkoxysilane. Examples of alkoxysilanes containing the group α-1 are n-decyltrimethoxysilane, n-undecyltrimethoxysilane, n-dodecyltrimethoxysilane, n-tridecyltrimethoxysilane, n-tetradecyltrimethoxysilane, n-pentadecyltrimethoxysilane, n-hexadecyltrimethoxysilane, n-heptadecyltrimethoxysilane, n-octadecyltrimethoxysilane, n-nonadecyltrimethoxysilane and n-eicosyltrimethoxysilane. Other examples of alkoxysilanes containing the group α-1 are n-decyltriethoxysilane, n-undecyltriethoxysilane, n-dodecyltriethoxysilane, n-tridecyltriethoxysilane, n-tetradecyltriethoxysilane, n-pentadecyltriethoxysilane, n-hexadecyltrimethoxysilane, n-heptadecyltrimethoxysilane, n-octadecyltrimethoxysilane, n-nonadecyltrimethoxysilane and n-eicosyltrimethoxysilane. Other examples of alkoxysilanes containing group α-1 are n-decylmethyldiethoxysilane, n-undecylmethyldiethoxysilane, n-dodecylmethyldiethoxysilane, n-tridecylmethyldiethoxysilane, n-tetradecylmethyldiethoxysilane, n-pentadecylmethyldiethoxysilane, n-hexadecylmethyldiethoxysilane, n-heptadecylmethyldiethoxysilane, n-octadecylmethyldiethoxysilane, n-nonadecylmethyldiethoxysilane and n-eicosylmethyldiethoxysilane. Furthermore, as examples of alkoxysilanes containing reactive functional groups, 8-glycidyloxyoctyltrimethoxysilane and 8-methacryloyloxyoctyltrimethoxysilane can be cited.

[0099] The light-absorbing composition may contain an alkoxysilane other than the alkoxysilane containing the group α-1. The light-absorbing composition may contain a silicon-containing compound β which is at least one compound selected from the group consisting of the alkoxysilane represented by formula (2), the hydrolyzate of the alkoxysilane and the condensate of the hydrolyzate of the alkoxysilane. The alkoxysilane represented by formula (2) is not limited to a specific alkoxysilane. Examples of the alkoxysilane represented by formula (2) are tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, methyltrimethoxysilane, methyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, butyltriethoxysilane, butyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, etc.

[0100] The light absorbing composition may contain a solvent. The solvent is not limited to a specific solvent. The solvent may be an organic solvent. The organic solvent is not limited to a specific organic solvent. Examples of organic solvents may be alcohols, may be xylenes, and may be cyclic compounds. Examples of alcohols are methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, 2-butanol, tert-butanol, n-pentanol, isopentanol, 2-methylbutanol, 2-pentanol, tert-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, 1-hexanol, 2-hexanol, 2-ethylbutanol, 1-heptanol, 2-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol, 2-octanol, n-nonanol, 2,6-dimethyl-4-heptanol, n-decanol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, and diacetone alcohol. Examples of the cyclic compound are dichlorobenzene, heptanone, cyclopentanone, cyclohexanone, cyclohexane, dimethylformamide, dimethylacetamide, toluene, tetrahydrofuran (THF) and oxetane.

[0101] The light-absorbing composition may include a phosphate. For example, when the light-absorbing compound includes phosphonic acid, the phosphate is a compound containing a phosphorus atom and an oxygen atom like phosphonic acid, so it is expected that the compatibility of the phosphate and the phosphonic acid is good. The phosphate may function as a dispersant for the light-absorbing compound, or may exist in a state where a part of it reacts with a metal component such as copper ions to form a compound. For example, a part of the phosphate may be coordinated to the light-absorbing compound, or a part may form a complex with the copper component of the light-absorbing compound. In this case, the compound containing the phosphate and the copper component may also absorb light of a specified wavelength.

[0102] Phosphate ester is not limited to a specific one. Phosphate ester has, for example, a polyoxyalkyl group. Examples of such phosphate ester include Plysurf A208N: polyoxyethylene alkyl (C12, C13) ether phosphate, Plysurf A208F: polyoxyethylene alkyl (C8) ether phosphate, Plysurf A208B: polyoxyethylene lauryl ether phosphate, Plysurf A219B: polyoxyethylene lauryl ether phosphate, Plysurf AL: polyoxyethylene styrenated phenyl ether phosphate, Plysurf A212C: polyoxyethylene tridecyl ether phosphate, or Plysurf A215C: polyoxyethylene tridecyl ether phosphate. All of them are products manufactured by Daiichi Kogyo Seiyaku Co., Ltd. In addition, examples of phosphate ester include NIKKOL DDP-2: polyoxyethylene alkyl ether phosphate, NIKKOL DDP-4: polyoxyethylene alkyl ether phosphate, or NIKKOL DDP-6: polyoxyethylene alkyl ether phosphate. These are all products manufactured by Nikkol Chemicals Co., Ltd. These phosphoric acid ester compounds may be used alone or in combination of two or more.

[0103] On the other hand, the light-absorbing composition may not substantially contain a phosphate ester. The presence of a silicon-containing compound α containing a group α-1 in the light-absorbing composition enables the light-absorbing compound to be well dispersed in the light-absorbing composition. For example, in the light-absorbing composition, the ratio of the amount of the phosphate ester to the amount of silicon atoms in the silicon-containing compound α may be 3.0 or less on a molar basis, and the light-absorbing composition may not contain a phosphate ester at all.

[0104] As described above, the light-absorbing composition may not contain a curable resin other than the silicon-containing compound. On the other hand, in addition to the silicon-containing compound α or β, the light-absorbing composition may also contain a curable component such as a curable resin. Examples of curable components are curable resins, curable polymers, and monomers, dimers, or oligomers that are precursors of curable polymers. The curable component can disperse or dissolve the light-absorbing compound and exist in a desired state. The curable component is in a liquid state in an uncured or unreacted state, and preferably can disperse or dissolve the light-absorbing compound containing phosphonic acid and copper components. In addition, as a curable resin, it is preferred to select a curable resin that can form a coating film by applying the light-absorbing composition on a specified object by a coating method such as spin coating, spray coating, dipping, and coating using a dispenser. As a curable resin, it is preferred to select a curable resin that has a smooth surface and a plate-like body with a thickness of 1 mm formed by curing the curable resin, and the transmission spectrum is 90% or more within a wavelength of 450nm to 800nm. Examples of curable resins include cyclic polyolefin resins, epoxy resins, polyimide resins, modified acrylic resins, silicone resins, and polyvinyl resins such as PVB, or precursors thereof. These curable resins may be used alone or in combination of two or more.

[0105] The light-absorbing composition may include an ultraviolet absorber that absorbs a portion of the light belonging to ultraviolet rays. The ultraviolet absorber is not limited to a specific compound. The ultraviolet absorber is, for example, a compound that does not have both a hydroxyl group and a carbonyl group in one molecule. For example, by coordinating a reaction substance or a precursor at a specific position in the molecule of the silicon-containing compound α, the curing of the light-absorbing composition can be promoted. For example, if there is a group that is easily coordinated by a substance other than a substance for the reaction of curing the light-absorbing composition, the effect of the catalyst may be weakened. In particular, it is believed that both the hydroxyl group and the carbonyl group have high electron donating properties, and the silicon-containing compound α reacts or coordinates with the ultraviolet absorber having these groups, and a part of them forms a complex. In this case, the ultraviolet absorption characteristics originally possessed by the ultraviolet absorber may change. In the case where the ultraviolet absorber is a compound that does not have both hydroxyl groups and carbonyl groups in one molecule, the silicon-containing compound α is difficult to form a complex with the ultraviolet absorber, and it is easy to exert the original ultraviolet absorption characteristics of the ultraviolet absorber. The ultraviolet absorber may contain only a group of either a hydroxyl group or a carbonyl group in one molecule.

[0106] The ultraviolet absorber is preferably selected from the aspects of absorbing light of a desired wavelength range, having compatibility with a specific solvent, being well dispersed in the light absorbing composition, and having excellent environmental resistance. Examples of ultraviolet absorbers are benzophenone compounds, benzotriazole compounds, salicylic acid compounds, and triazine compounds. For example, as ultraviolet absorbers, Tinuvin PS, Tinuvin 99-2, Tinuvin 234, Tinuvin 326, Tinuvin 329, Tinuvin 900, Tinuvin 928, Tinuvin 405, and Tinuvin 460 can be used. These are ultraviolet absorbers manufactured by BASF, and Tinuvin is a registered trademark.

[0107] The light-absorbing composition may contain water as needed. The light-absorbing composition, for example, contains a predetermined amount of alkoxysilane. For example, the silicon-containing compound α can be contained in the light-absorbing composition as an alkoxysilane. In the light-absorbing composition, hydrolysis of the alkoxysilane equivalent to the silicon-containing compound α or the alkoxysilane not equivalent to the silicon-containing compound α may occur. For the hydrolysis, water may be contained in the light-absorbing composition. The light-absorbing composition may contain an appropriate amount of water depending on the purpose, function and storage environment of the light-absorbing composition.

[0108] On the other hand, in the process of curing the light absorbing composition to produce the light absorber, a humidification treatment may be performed as post-curing. In the humidification treatment, water components at the molecular level enter the light absorber or its precursor, which can promote the hydrolysis of alkoxysilane and the formation reaction of siloxane bonds after hydrolysis. For example, in the case of using a process including a humidification treatment, the light absorbing composition may not substantially contain water. In this case, the light absorbing composition may contain a water component that is pre-coordinated to a compound such as a hydrate, or a water component that is necessarily contained without intentional addition.

[0109] The method for producing the light-absorbing composition is not limited to a specific method. For example, the method for producing the light-absorbing composition includes the following (I), (II), and (III).

[0110] (I) A light-absorbing compound dispersion is prepared in which a light-absorbing compound containing phosphonic acid and a copper component is dispersed in a solvent.

[0111] (II) The light absorbing compound dispersion is mixed with an alkoxysilane containing a group having 10 or more carbon atoms or a hydrolyzate of the alkoxysilane.

[0112] (III) Removing a portion of the solvent from the light absorbing compound dispersion.

[0113] like Figure 1A to Figure 1DAs shown, a light absorber 10 can be provided. The light absorber 10 is provided, for example, in the form of a cured product of the above-mentioned light absorbing composition. In this case, the light absorber 10 contains a polysiloxane having a group α-1 and containing a siloxane bond. Figure 1A As shown, for example, the light absorber 10 can constitute the filter 1a alone. In this case, the filter 1a can be in the form of a film or a light absorbing film. Figure 1B As shown, the optical filter 1 b may be formed by the light absorber 10 and the substrate 20 .

[0114] In the light absorber 10, the average value T A 460-600 The average value T A 460-600 It is the average value of the transmittance in the wavelength range of 460nm to 600nm of the transmission spectrum obtained by making light enter the light absorber 10 at an incident angle of 0°. The value obtained by dividing the optical density OD of the light absorber 10 at a wavelength λ by the thickness of the light absorber 10 is expressed as η λ [μm -1 ] Optical density OD is calculated from OD = -log 10 [T(λ) / 100] indicates that T(λ) is a numerical value expressing the transmittance at a wavelength λ in %. In this case, in the light absorber 10, 0.009≤η is satisfied. 380 and 0.008≤η 750 conditions. Thus, the light absorber 10 can easily have a transmittance close to the visual sensitivity curve of humans even if it is thin. The transmittance of the visible light region of the light absorber 10 is high, and the light absorber 10 can effectively shield light of wavelengths other than visible light by absorption. In addition, the thin light absorber 10 can be used as an infrared cutoff filter or an ultraviolet cutoff filter. Therefore, the filter arranged near the sensor or the light receiving surface can be easily thinned, and the light absorber 10 can contribute to the low height of the camera device and the light receiving devices such as the ambient light sensor and the illuminance sensor. The transmission spectrum of the light absorber 10 is obtained, for example, by measuring the transmitted light when the light is incident on the light absorber 10 at an incident angle of 0° using a spectrophotometer.

[0115] In the light absorber 10, the average value T A 460-600 It is preferably 82% or more, and more preferably 84% or more. As a result, the transmittance of the light absorber 10 in the visible light region becomes higher, and the light absorber 10 is more likely to have a transmittance close to the visual sensitivity curve of humans.

[0116] In the light absorber 10, it is preferable to satisfy 0.012≤η 380 In the light absorber 10, preferably 0.010≤η is satisfied. 750Thus, light of wavelengths other than visible light can be shielded more effectively, and the light absorber 10 is more likely to have a transmittance close to the visual sensitivity curve of humans.

[0117] The light absorber 10 has a haze of, for example, less than 0.2%. For example, the filter is designed in such a way that the transmission spectrum and reflection spectrum of the filter assembled into the imaging device meet the prescribed conditions. On the other hand, for example, even in the case where the filter or the light absorber has a high transmittance in the visible light region, if the haze is large, sometimes part of the light incident on the filter or the light absorber is scattered or diffused inside it, showing a turbid or opaque optical property. This may affect the formation of a clear image. On the other hand, by making the light absorber 10 have a haze of less than 0.2%, the transparency of the light absorber 10 is high, for example, when the light absorber 10 is used in an imaging device, it is easy to obtain a high-quality image through the imaging device. The haze can be measured using the light absorber 10 alone, or it can be measured in a state where the light absorber 10 is arranged on a glass or resin substrate.

[0118] The light absorber 10 preferably has a haze of 0.18% or less, and more preferably has a haze of 0.15% or less.

[0119] The light absorber 10 may satisfy, for example, 0.018≤η 900 The condition of 0.013≤η can also be satisfied 1100 The light absorber 10 may satisfy 0.016≤η 800 The condition of 0.013≤η can also be satisfied 1000 Therefore, even if the light absorber 10 is thin, it is easier to have a transmittance close to the visual sensitivity curve of humans.

[0120] The light absorber 10 preferably satisfies 0.020≤η 900 The condition can satisfy 0.015≤η 1100 The condition can satisfy 0.018≤η 800 The condition of 0.018≤η can also be satisfied 1000 conditions.

[0121] For example, the light absorber 10 satisfies T A 300-380 ≤1.5% and T A 750-1100 ≤2.0% condition. T A 300-380 It is the average value of the transmittance in the wavelength range of 300 nm to 380 nm of the transmission spectrum obtained by making light incident on the light absorber 10 at an incident angle of 0°. A 750-1100It is the average value of the transmittance in the wavelength range of 750 nm to 1100 nm of the transmission spectrum. In this case, the light absorber 10 is more likely to have a transmittance close to the visual sensitivity curve of humans.

[0122] The light absorber 10 preferably satisfies T A 300-380 ≤1.2%, preferably satisfying T A 300-380 ≤1.0%. The light absorber 10 preferably satisfies T A 750-1100 ≤1.5%, preferably satisfying T A 750-1100 ≤1.0% or less.

[0123] In the light absorber 10, for example, 390nm≤λ may be satisfied. 0 UV ≤450nm and meet the conditions of 600nm≤λ 0 IR ≤680nm. 0 UV It is the first ultraviolet cutoff wavelength where the transmittance reaches 50% in the wavelength range of 350nm to 460nm. 0 IR The first infrared cutoff wavelength at which the transmittance reaches 50% in the wavelength range of 600 nm to 700 nm. In the light absorber 10, preferably, 393 nm ≤ λ 0 UV ≤450nm, more preferably 395nm≤λ 0 UV In the light absorber 10, it is preferred that 605nm≤λ 0 IR ≤680nm, more preferably 610nm≤λ 0 IR ≤680nm condition.

[0124] For example, the light absorber 10 satisfies R A 450-550 ≤10% and meet the R A 700-1000 ≤8% condition. A 450-550 It is the average value of the reflectivity in the wavelength range of 450nm to 550nm. A 700-1000It is the average value of the reflectivity in the wavelength range of 700nm to 1000nm. The reflectivity is determined based on, for example, a reflection spectrum obtained by causing light of 300nm to 1200nm to be incident on the light absorber 10 at an incident angle of 5°. If the light absorber 10 absorbs a portion of light of a specific wavelength in a manner that satisfies these conditions, for example, in an imaging device incorporating the light absorber 10, it is possible to suppress the following situation: the reflected light generates reflection or scattering of light inside the housing or aperture of the imaging device, and ghosting or flare, etc., which reduces the contrast of the captured image.

[0125] The light absorber 10 preferably satisfies R A 450-550 ≤8%. The light absorber 10 preferably satisfies R A 700-1000 ≤6% condition.

[0126] For example, the light absorber 10 satisfies R 380 <R 350 Conditions. 380 is the reflectivity at a wavelength of 380nm, R 350 It is the reflectance at a wavelength of 350 nm. In this case, it is easier to suppress the occurrence of ghosting or flare that causes a decrease in image contrast.

[0127] Regarding the above transmittance, η λ The conditions of , haze and reflectivity can be satisfied in the optical filter having the light absorber 10 .

[0128] The thickness d of the light absorber 10 L It is not limited to a specific value. Thickness d L For example, it is 150 μm or less, preferably 120 μm or less, and more preferably 110 μm or less.

[0129] like Figure 1A As shown in FIG. 1 , when the light absorber 10 alone constitutes the optical filter 1a, the thickness of the optical filter 1a can be easily reduced, and the optical filter 1a can be in the form of a film. Therefore, the optical filter 1a can easily contribute to the lowering of the height of the device in which the optical filter 1a is assembled. Figure 1B As shown, it is also possible to provide an optical filter 1b including the light absorber 10 and the substrate 20. In this case, the rigidity or mechanical strength of the optical filter 1b is likely to be increased, and the optical filter 1b can be provided as a rigid optical filter.

[0130] The substrate 20 can be formed of, for example, glass, resin, or metal. As for the type and optical properties of the substrate 20, as long as the light absorber 10 or the filter including the light absorber 10 has the desired transmittance, η λ, haze and reflectivity are not limited to a specific form. In addition, the shape of the substrate 20 is not limited to a specific shape. Figure 1B As shown, the substrate 20 is, for example, in the form of a flat plate. In this case, the light absorbing composition is easy to apply, and the versatility of the filter 1b is likely to be increased. On the other hand, the substrate 20 may include a curved surface, and may also include a convex surface or a concave surface. The substrate 20 may also be in a shape other than a plate. The substrate 20 may also be an optical element, examples of which are lenses, polarizing elements, prisms, reflective elements, and diffraction gratings. These optical elements may include curved surfaces and flat surfaces. Other examples of the substrate 20 are photoelectric conversion elements such as photodiodes and phototransistors, image sensors in which multiple photoelectric conversion elements such as CCDs or CMOSs ​​are arranged, and image sensors equivalent to the image sensors. Depending on the circumstances, the light absorber 10 may also be directly disposed on the light receiving surface or window glass. Other examples of the substrate 20 are display devices such as displays in portable terminals.

[0131] The substrate 20 may be transparent. In this case, the transmission spectrum of the light absorber 10 is easily reflected in the transmission spectrum of the filter 1b. For example, when the substrate 20 is transparent, in the transmission spectrum of a parallel plate with a thickness of 3 mm formed of the same material as the substrate 20, the transmittance in the wavelength range of 360 nm to 900 nm may be 90% or more, and the transmittance in the wavelength range of 350 nm to 1200 nm may be 85% or more. A typical example of the material of the substrate 20 having such a transmission characteristic is glass. The substrate 20 may be a transparent glass substrate containing silicate glass. Examples of silicate glass are soda-lime glass and borosilicate glass. An example of borosilicate glass is D263T eco manufactured by SCHOTT. Figure 2 The transmission spectrum of a D263T eco plate having a thickness of 3 mm is shown. In the transmission spectrum, the transmittance in the wavelength range of 360 nm to 2300 nm is 90% or more, and the transmittance in the wavelength range of 335 nm to 2500 nm is 85% or more. The glass contained in the substrate 20 can be a phosphate glass or a fluorophosphate glass containing coloring components such as Cu and Co. The glass containing the coloring component is, for example, an infrared absorbing glass, in which case the substrate 20 itself has light absorption. In the case where the substrate 20 is a substrate containing infrared absorbing glass, by adjusting the light absorption and transmission spectrum of both the light absorber 10 and the substrate 20, the filter 1b can easily have the desired optical characteristics. In addition, the design freedom of the filter 1b can easily become high.

[0132] The substrate 20 may include a resin. Examples of the resin included in the substrate 20 include cycloolefin resins such as norbornene resins, polyarylate resins, acrylic resins, modified acrylic resins, polyimide resins, polyetherimide resins, polyolefin resins, polysulfone resins, polyethersulfone resins, polycarbonate resins, and silicone resins. Resins are easier to process and mold than glass. Therefore, when the substrate 20 includes a resin, it is easy to obtain substrates 20 of various shapes such as optical elements.

[0133] like Figure 1C As shown, the optical filter 1c includes a light absorber 10 and a light absorbing substrate 21. The light absorbing substrate 21 is a substrate having a function of absorbing a part of light of a specific wavelength and on the surface of which the light absorber 10 can be arranged. The light absorbing substrate 21 may include glass containing the above-mentioned coloring component, or may be a resin substrate containing a pigment, a pigment, and a colorant.

[0134] The optical filter having the light absorber 10 may be provided with an anti-reflection film or a light-reduction reflection film for preventing or reducing the surface reflection of light incident on the optical filter. In this case, the anti-reflection film or the light-reduction reflection film (hereinafter collectively referred to as "anti-reflection film") constitutes the surface of the optical filter. Figure 1D As shown in FIG. 1 , the optical filter 1d includes a light absorber 10 and anti-reflection films 31a and 31b provided on the surface of the light absorber 10. The anti-reflection films 31a and 31b are arranged along the surface of the light absorber 10. For example, in the case where the optical filter includes a transparent substrate and the light absorber 10 arranged on the transparent substrate, the anti-reflection film may be arranged on the surface of the light absorber 10 and on the surface of the transparent substrate that is not in contact with the light absorber 10. Such a light absorber provided with an anti-reflection film and an optical filter including such a light absorber and an anti-reflection film are also included in the scope of the gist of the present invention.

[0135] The antireflection film can, for example, increase the transmittance of the light absorber 10 or the filter in the wavelength band (transmission band) in which light passes through the light absorber 10 or the filter having the light absorber 10. The transmission band is, for example, a band in which the transmittance reaches 50% or more in the transmission spectrum at an incident angle of 0° of the light absorber or the filter.

[0136] When an antireflection film is formed on the light absorber 10, the optical filter, or a transparent substrate (e.g., D263Teco manufactured by SCHOOT) for supporting them, in a reflection spectrum obtained by causing light of a wavelength of 300 nm to 1200 nm to be incident at an incident angle of 5°, the reflectivity within a wavelength range of 400 nm to 600 nm is, for example, 1% or less. The reflectivity is preferably 0.5% or less, and more preferably 0.25% or less.

[0137] In the reflection spectrum, the average value of the reflectivity within the wavelength range of 700 nm to 1200 nm is, for example, 1% or less. In this case, ghosting or flare is less likely to occur in an image obtained by reflecting part of the infrared light. The average value of the reflectivity is preferably 0.5% or less, more preferably 0.25% or less.

[0138] In the case where an anti-reflection film is formed on the light absorber 10, etc., in the reflection spectrum obtained by making light with a wavelength of 300nm to 1200nm incident at an incident angle of 50°, the reflectivity within the wavelength range of 400nm to 600nm is, for example, 3% or less. In this case, even when the incident angle to the light absorber 10 or the filter provided with the light absorber 10 is large, the reflectivity of the light absorber 10 or the filter provided with the light absorber 10 is low. The reflectivity is preferably 1% or less. In the reflection spectrum, the reflectivity within the wavelength range of 700nm to 1200nm is, for example, 3% or less. In this case, even when the incident angle to the light absorber 10 or the filter provided with the light absorber 10 is large, the reflectivity of the light absorber 10 or the filter provided with the light absorber 10 is low. The reflectivity is preferably 1.5% or less.

[0139] The anti-reflection film is not limited to a specific film. The anti-reflection film includes at least one layer selected from the group consisting of the following (a), (b) and (c). The anti-reflection film may include two or more layers selected from the group. Figure 1D In the figure, the anti-reflection films 31a and 32a are each described as an example of a single layer, but the figure is a functional depiction in a manner of distinguishing each anti-reflection film from the light absorber 10. In fact, the anti-reflection films 31a and 32a can be a single-layer film composed of a single layer formed by substantially the same material, or a multi-layer film composed of multiple layers formed by multiple different materials.

[0140] (a) A layer formed by a sol-gel method using a reactive material containing silicon.

[0141] (b) A layer formed by a sol-gel method using a reactive material containing silicon, and the layer further contains fine particles.

[0142] (c) A layer formed by a physical film forming method such as vacuum evaporation and sputtering.

[0143] Regarding the layer of (a) above, the reactive material containing silicon is not limited to a specific material. The reactive material preferably contains trifunctional silanes such as methyltriethoxysilane (MTES) and tetrafunctional silanes such as tetraethoxysilane (TEOS). Tetrafunctional silane is important for forming a layer with a firm and dense skeleton. On the other hand, it is difficult to control the reactivity with only tetrafunctional silane, and the selectivity of porosity is lacking. In addition, cracks are easily generated. By adding trifunctional silane, the flexibility of the silica skeleton is improved, the controllability of the porosity is improved, and cracks are not easily generated. As a result, by adjusting the porosity, the refractive index required for the anti-reflection film can be adjusted. The organic functional group contained in the trifunctional silane is not limited to a specific functional group. The organic functional group is, for example, a methyl group. In this case, when the trifunctional silane is combined with the tetrafunctional silane, a homogeneous liquid and a coating can be easily formed. The ratio of the amount of the trifunctional silane to the amount of the tetrafunctional silane is not limited to a specific value. The ratio is, for example, 1 / 3 to 5 on a molar basis. Thus, the trifunctional silane can suppress the occurrence of cracks in the antireflection film, and the tetrafunctional silane can form a strong skeleton. The reactive material containing silicon may further contain a difunctional silane.

[0144] The trifunctional silane is not limited to a specific silane. Examples of the trifunctional silane include methyltriethoxysilane, methyltrimethoxysilane, ethyltriethoxysilane, ethyltrimethoxysilane, propyltriethoxysilane, propyltrimethoxysilane, butyltriethoxysilane, butyltrimethoxysilane, pentyltrimethoxysilane, pentyltriethoxysilane, hexyltriethoxysilane, and hexyltrimethoxysilane, and may be a trifunctional silane having an alkyl group directly bonded to a silicon atom (Si). The tetrafunctional silane is not limited to a specific silane. Examples of the tetrafunctional silane include tetraethoxysilane, tetramethoxysilane, tetrapropoxysilane, and tetrabutoxysilane.

[0145] The silane compound contained in the reactive material containing silicon also becomes a hydrolyzate of the silane compound containing a silanol group by hydrolysis. Furthermore, by polycondensation of the hydrolyzate, trifunctional silane can become (poly)silsesquioxane, and tetrafunctional silane can be converted into a silicon dioxide structure.

[0146] The refractive index of (poly)silsesquioxane and silicon dioxide is as low as about 1.46, so it is easy to form a layer having a low refractive index. A layer containing at least one selected from the group consisting of (poly)silsesquioxane and silicon dioxide is suitable as a layer included in the antireflection film of the light absorber 10 or an optical filter having the light absorber 10.

[0147] The calcination of the coating film of the reactive material can be performed, for example, at a temperature in the range of 60° C. to 170° C. The calcination temperature is preferably 60° C. to 150° C., more preferably 60° C. to 115° C.

[0148] Regarding the layer of (b) above, the layer containing the reactive material containing silicon, the hydrolyzate of the reactive material, or the condensate of the hydrolyzate contains particles. The particles, for example, contain at least one selected from the group consisting of silicon dioxide, titanium dioxide, zirconium oxide, aluminum oxide and magnesium fluoride. The refractive index of the material forming the particles is, for example, 1.30 to 2.55. The particles preferably contain silicon dioxide. In the layer containing silicon dioxide or (poly) silsesquioxane, they act as a binder surrounding the particles. Therefore, through silanol groups, etc., the bonding force between the particles and the binder is improved, the weather resistance of the anti-reflection film is easily improved, and the reliability of the anti-reflection film can be expected to be improved.

[0149] The particles contained in the layer of (b) may be hollow particles. The layer containing hollow particles, silsesquioxane and silica is distinguished as the layer of (b1) from the layer containing solid particles described later. Hollow particles contain empty spaces inside them, so their refractive index tends to become very low. The refractive index of hollow particles is, for example, 1.02 to 1.50. The average particle size of the hollow particles is, for example, 5 nm to 200 nm. The average particle size of the microparticles is, for example, the particle size (median particle size) at which the accumulation from the smaller side reaches 50% in the number-based particle size distribution curve measured by the laser diffraction / scattering method using a laser diffraction / scattering particle size analyzer. As a laser diffraction / scattering particle size analyzer, for example, the laser diffraction / scattering particle size distribution measuring device "LA-960V2 Series" manufactured by Horiba, Ltd. can be used. In addition, the average particle size of the microparticles can be determined by observing the cross section of the structure of the layer (b1) by magnifying it 100,000 times with a scanning electron microscope (SEM), measuring the particle size of the microparticles contained in its field of view and a specified range (e.g., 500 nm square), and finding the average value. In particular, this method can be used to find the diameter of the microparticles contained in a solid or solid layer. In addition, the content of the microparticles in the layer (b1) is, for example, 5% to 95% by mass. In addition, the content of the microparticles in the layer (b1) is, for example, 30% to 99% by volume. The content of the microparticles in the layer (b1) is obtained as follows: Similarly, after observing the cross section of the structure of the layer (b1) by magnifying it 100,000 times with SEM, the ratio of the volume of the microparticles to the volume of the layer (b1) is calculated, and thus obtained. Generally, in the layer (b1), there is a tendency that the greater the proportion of hollow microparticles, the lower the refractive index of the layer. The content of the microparticles in the layer (b1) can be, for example, 75% to 99% by volume.

[0150] In a layer containing such hollow particles and containing at least one selected from the group consisting of silica and (poly)silsesquioxane, the refractive index of the layer tends to become very low. For example, the refractive index of the layer (b1) is, for example, 1.00 to 1.45. The hollow particles can be hollow silica particles, for example, Thrulya 4110 or Thrulya 1110 manufactured by JGC Catalysts & Chemicals Co., Ltd. can be used. The refractive index of the layer (b1) can be determined as follows. A laminate comprising a substrate having a known refractive index within a specific wavelength range and a layer (b1) disposed on the surface of the substrate is prepared, and the reflection spectrum of the laminate is measured. Furthermore, the thickness of the layer (b1) is determined by obtaining it from an enlarged image of a cross section using an SEM or by measuring it using a laser length measuring microscope. Using the refractive index of layer (b1) as a variable, the refractive index that best matches the measured reflection spectrum is determined.

[0151] In a layer comprising at least one selected from the group consisting of silica and (poly)silsesquioxane, when comparing the case where hollow particles are included with the case where hollow particles are not included, the refractive index of the former layer tends to be lower. Therefore, in a structure in which a layer comprising at least one selected from the group consisting of silica and (poly)silsesquioxane and comprising hollow particles, a layer comprising at least one selected from the group consisting of silica and (poly)silsesquioxane and not comprising hollow particles, and an optical filter or light absorber 10 are sequentially stacked, a high anti-reflection effect can sometimes be expected from the anti-reflection film.

[0152] The microparticles contained in the layer of (b) may be solid particles. The layer containing solid particles, silsesquioxane and silica is distinguished as the layer of (b2) from the above-mentioned layer containing hollow particles. The refractive index of the solid particles is, for example, 1.25 to 2.75. In the case where the layer of (b) contains solid particles, the refractive index of the layer of (b2) is, for example, 1.40 to 2.50. The average particle size of the solid particles may be, for example, 2 nm to 200 nm. The solid particles may be solid silica particles, for example, SNOWTEX MP-2040 manufactured by Nissan Chemical Co., Ltd. may be used. The refractive index of the layer of (b2) can be obtained by the same method as the above-mentioned method for obtaining the refractive index of the layer of (b1).

[0153] The layer of (b2) may contain particles having a higher refractive index, or may be formed into a layer having a higher refractive index. For example, the layer of (b2) may contain one selected from the group consisting of TiO2 (titanium oxide, refractive index 2.33 to 2.55), Ta2O5 (tantalum oxide, refractive index 2.16), Nb2O5 (niobium oxide, refractive index 2.33) and Si3N4 (silicon nitride, refractive index 2.02), or may contain a mixture of at least two selected from the group. In particular, the layer of (b2) may contain TiO2 particles. In this case, the average particle size of the TiO2 particles may be 2nm to 200nm. The content of TiO2 particles in the layer of (b2) is, for example, 2% to 50%. As TiO2 particles, for example, NS405 manufactured by Tayca and TTO-51A manufactured by Ishihara Sangyo Co., Ltd. may be used. In addition, the average particle size of the particles contained in the layer (b2) can be determined by the same method as the average particle size of the particles contained in the layer (b1). The content of the particles contained in the layer (b2) is, for example, 5% to 95% by mass. The content of the particles in the layer (b2) is, for example, 30% to 99% by volume. The content of the particles in the layer (b2) can be obtained by the method of obtaining the volume % of the particles contained in the layer (b1).

[0154] In order to improve the adhesion or wettability with the binder or matrix, these particles may be surface treated with a silane coupling agent or a titanium coupling agent, etc. This surface treatment is also effective for particles other than TiO2 particles and SiO2 particles.

[0155] The layers of (a), (b1) and (b2) contain silicon compounds as binders or substrates in the same manner as the light absorbers containing silicon compounds. Therefore, alkoxy groups and silanol groups as their hydrolyzates are present between the layers and react with hydroxyl groups, etc., and it is expected that the adhesion will be improved, which can contribute to the improvement of peeling resistance. In addition, the layers of (a), (b1) and (b2) are classified into, for example, low refractive index layers, medium refractive index layers and high refractive index layers. In this case, the low refractive index layer is a layer of (b1) containing at least one selected from the group consisting of silicon dioxide and (poly) silsesquioxanes and containing hollow particles. The medium refractive index layer is a layer of (a) containing at least one selected from the group consisting of silicon dioxide and (poly) silsesquioxanes and not containing hollow particles. The high refractive index layer is a layer of (b2) containing at least one selected from the group consisting of silicon dioxide and (poly) silsesquioxanes and also containing particles with a higher refractive index such as TiO2 particles. For example, the antireflection film may be formed by taking into account the combination of these layers, the thickness of the layers, the number of layers, the repeated pattern in the combination of layers, etc. By comparing the refractive index of each layer, the condition that the refractive index of the layer (b1) < the refractive index of the layer (a) < the refractive index of the layer (b2) is satisfied.

[0156] The anti-reflection film may be a layer (b1) containing silicon dioxide, (poly) silsesquioxane and hollow particles and a layer (b2) containing solid particles with a higher refractive index such as silicon dioxide, (poly) silsesquioxane and TiO2 particles. The refractive index of (b2) is higher than that of the layer (b1). In this way, from the perspective of expanding the anti-reflection band and reducing the reflectivity, laminating layers of substantially different refractive indices to form an anti-reflection film has a great effect.

[0157] The layer of (a), the layer of (b1) and the layer of (b2) can be made by a known method. Specifically, a trifunctional alkoxysilane that will become a material of silsesquioxane, a tetrafunctional silane that will become a material of silicon dioxide, an acidic or alkaline catalyst and water for hydrolysis are mixed in an organic solvent having the solubility of alkoxysilane and water, and hydrolyzed to obtain a sol-like precursor of layers such as (a), (b1) and (b2). In particular, in the precursor of layers such as (b1) and (b2), hollow particles or solid particles are added as needed. Silane coupling agents etc. can be made to act on hollow particles or solid particles, and silane treatment is performed in advance. Thus, it is possible to improve the adhesion and wettability with a binder (a compound that contains silsesquioxane and silicon dioxide and is bonded to particles).

[0158] The precursor of the sol prepared in this way is applied to the substrate requiring an anti-reflection effect, here, on the surface of a light absorber or a filter, by adjusting the coating conditions and the coating amount in a manner to obtain a specified thickness. Examples of coating methods are spin coating, dipping, roller coating, distribution, spray coating and rod coating, and the coating method may also be a method other than these. After the precursor of the sol is applied, reactions such as hydrolysis of alkoxysilane and polymerization of the hydrolyzate proceed, and the precursor of the sol solidifies. In addition, in order to promote the reaction or remove by-products, it is preferably heated. In addition, in addition to the reaction in the sol, a solidification process that produces a gel by evaporation or drying of a solvent or liquid component may also be included.

[0159] The layer (c) can be formed as a layer composed of a dielectric or metal oxide by a physical vapor deposition method such as vacuum vapor deposition including ion-assisted vapor deposition (IAD), sputtering, or ion plating. The material constituting the layer (c) is not limited to a specific material. The layer (c) may include, for example, a material selected from SiO2, TiO2, Ta2O3, SnO2, In2O3, Nb2O5, Si3N4, TiN x At least one material selected from the group consisting of MgF2 and MgF2. The layer (c) may be composed of a material in which these compounds are mixed at a predetermined ratio, and the refractive index of the layer included in the layer (c) may be adjusted by adjusting the mixing ratio of materials in which different compounds are mixed.

[0160] The layer of (c) can be a single layer consisting of only the same material, or can be a multilayer formed by laminating two or more layers of materials of different types selected from the above-mentioned compound and the mixture of the above-mentioned compound. In the case where the layer of (c) is multilayer, for example, the thickness and repetition number of the layer consisting of materials with higher refractive indexes such as TiO2, Ta2O3 and Nb2O5 or their mixtures and the layer consisting of materials with lower refractive indexes such as SiO2 and MgF2 or their mixtures can be adjusted, and these layers are alternately laminated to form an anti-reflection film. In this case, from the aspects of the expansion of the anti-reflection band or the reduction of reflectivity, it is expected that laminating layers of substantially different refractive indices to form an anti-reflection film also has a great effect, which is beneficial for users of optical filters or light absorbers.

[0161] In the optical filter 1d in which the antireflection films 31a and 32a are provided on both surfaces of the light absorber 10, the average value T2 of the transmittance within the wavelength range of 400nm to 600nm is A 460-600 It is preferably 90% or more, and more preferably 94% or more. In this case, light passes through the optical filter 1d with little attenuation in the visible light region. Therefore, the optical filter 1d has extremely suitable properties as an optical filter for an imaging device.

[0162] In the optical filter 1d in which the antireflection films 31a and 32a are provided on both surfaces of the light absorber 10, the value obtained by dividing the optical density at the wavelength λ, that is, the OD value, by the thickness of the light absorber (the thickness obtained by subtracting the thickness of the antireflection film from the thickness of the filter) is set as η. 2-λ [μm -1 ], preferably 0.009≤η 2-380 and 0.008≤η 2-750 , further preferably 0.012≤η 2-380 and 0.010≤η 2-750 .

[0163] In the optical filter 1d having antireflection films 31a and 32a on both surfaces of the light absorber 10, similarly to the optical filter without antireflection films, the optical filter 1d preferably has a haze of less than 0.2%, more preferably 0.18% or less, and particularly preferably 0.15% or less.

[0164] In the optical filter 1d in which the antireflection films 31a and 32a are provided on both surfaces of the light absorber 10, for example, 0.020≤η can be satisfied. 2-900 The condition of 0.013≤η can also be satisfied 2-1100 Furthermore, the filter 1d can satisfy 0.020≤η 2-800 The condition of 0.012≤η can also be satisfied 2-1000 .

[0165] The filter 1d preferably satisfies 0.022≤η 2-900 The condition can satisfy 0.015≤η 2-1100 The condition can satisfy 0.025≤η 2-800 The condition of 0.015≤η can also be satisfied 2-1000 .

[0166] The optical filter 1d having antireflection films 31a and 32a on both surfaces of the light absorber 10 can satisfy T2 A 300-380 ≤1.5% and T2 A 750-1100 ≤2.0%, preferably T2 A 300-380 ≤1.2% and T2 A 750-1100 ≤1.5%, and preferably can satisfy T2 A 300-380 ≤1.0% and T2 A 750-1100 ≤1.0% condition. T2 A 300-380 It is the average transmittance within the wavelength range of 300nm to 380nm. A 750-1100 It is the average value of transmittance within the wavelength range of 750nm to 1100nm.

[0167] The optical filter 1d having antireflection films 31a and 32a provided on both surfaces of the light absorber 10 satisfies, for example, 390nm≤λ2 0 UV ≤450nm conditions and 600nm≤λ2 0 IR ≤680nm. λ2 0 UV The second ultraviolet cutoff wavelength at which the transmittance reaches 50% in the wavelength range of 350nm to 460nm in the filter 1d, λ2 0 IR This is the second infrared cutoff wavelength at which the transmittance reaches 50% in the wavelength range of 600 nm to 700 nm in the optical filter 1d.

[0168] An ambient light sensor having a light absorber 10 or a filter including the light absorber 10 may also be provided. An ambient light sensor is a device mounted on a device and detects brightness or color tone around the device. The properties of light around the device are identified by the ambient light sensor, for example, the brightness of a display device such as a display mounted on the device is automatically adjusted. An ambient light sensor is sometimes also called a luminance sensor or an illuminance sensor.

[0169] Figure 3A FIG. 1 is a cross-sectional view showing an example of an ambient light sensor. Figure 3A As shown, the ambient light sensor 2a, for example, includes a circuit substrate 3, a photoelectric conversion element 4, a housing 5, and an optical filter 1a. The ambient light sensor 2a, for example, detects the properties of light belonging to the visible light region among the properties of light around a device having the ambient light sensor 2a. The circuit substrate 3 supports the ambient light sensor 2a and electrically connects the ambient light sensor 2a to peripheral devices. The photoelectric conversion element 4 is disposed on the circuit substrate 3 and includes, for example, elements such as a photodiode or a phototransistor. The housing 5 is disposed on the circuit substrate 3 and surrounds the photoelectric conversion element 4. The optical filter 1a, for example, is disposed in front of the photoelectric conversion element 4 and shields a portion of light traveling toward the photoelectric conversion element 4. The optical filter 1a, for example, shields a portion of light belonging to ultraviolet rays or infrared rays. The optical filter 1a is supported by the housing 5.

[0170] Ambient light sensors can be used as Figure 3A As shown in FIG. 1 , a filter having a light absorber 10 may be provided. Figure 3B As shown in the figure, an integrated photoelectric conversion element is provided in which the light absorber 10 and the photoelectric conversion element are integrated. Figure 3B The photoelectric conversion element 2b shown has a light receiving surface 2f and a light absorber 10. In the photoelectric conversion element 2b, the light receiving surface 2f and the light absorber 10 are arranged in sequence. The photoelectric conversion element 2b is an integrated photoelectric conversion element. The integrated photoelectric conversion element is obtained, for example, by coating the above-mentioned light absorbing composition on the surface of the light receiving surface (window) of the photoelectric conversion element and curing it to form the light absorber 10. When such a photoelectric conversion element is used, there is no need to use the light absorber separately from the photoelectric conversion element. According to such an ambient light sensor, light outside the visible light region, such as a part of ultraviolet rays or infrared rays, can be shielded by absorption in the light absorber 10. As an ambient light sensor dedicated to detecting light in a roughly visible light region, the ease of operation of the ambient light sensor can be significantly improved. In addition, simplification of the supply chain of product distribution can also be expected.

[0171] In the photoelectric conversion element 2b, for example, a first electrode E1 and a photoelectric conversion layer L are sequentially stacked on a circuit board 3. Furthermore, on the photoelectric conversion layer L, a second electrode E2, a light receiving surface 2f, and a light absorber 10 are arranged.

[0172] In order to reduce the reflectivity and increase the transmittance of light of a predetermined wavelength, an antireflection film or an antireflection film may be provided on the surface of the light absorber 10 or the optical filter including the light absorber 10 mounted in the ambient light sensor.

[0173] An imaging device or camera module having a light absorber 10 or a filter including the light absorber 10 can be provided. The imaging device or camera module, for example, has an image sensor, a circuit substrate, a lens system, and a filter including the light absorber 10. In the image sensor, for example, a plurality of photoelectric conversion elements such as CCD or CMOS are arranged. The circuit substrate electrically connects the image sensor to an external device. The lens system includes one or more lens groups for focusing light from a subject, etc., on the image sensor and forming an image. The light absorber 10 or the filter including the light absorber 10 can shield a portion of light belonging to ultraviolet rays and infrared rays.

[0174] For example, in an imaging device equipped with the light absorber 10 or a filter having the light absorber 10, part of the light belonging to ultraviolet rays and infrared rays is shielded by absorption, and light belonging to the visible light region passes through the filter toward the image sensor. In the case where the filter has a function of reflecting part of the light by a dielectric multilayer film or the like, part of the light reflected by the filter is reflected inside the housing or on the surface of a lens system arranged in front of the filter, or part of the reflected light projects an aperture or its shape and reaches the light receiving surface of the imaging element, thereby making phenomena such as ghosting and flare that deteriorate the contrast more obvious. On the other hand, according to the imaging device equipped with the filter having the light absorber 10, such phenomena are less likely to occur, and ghosting and flare are less likely to be conspicuous in the acquired image.

[0175] Figure 4A 1 is a diagram showing an example of an imaging device. This diagram shows an overview of the imaging device, and only the elements necessary for explanation are schematically described, and other parts or elements are omitted. Figure 4A As shown in FIG. 1 , the imaging device 6a includes an image sensor 7, a lens system 8, and an optical filter 1a. In the imaging device 6a, the optical filter 1a is disposed, for example, between the image sensor 7 and the lens system 8 and directly in front of the image sensor 7. The arrangement of the optical filter is not limited to Figure 4AThe filter may also be arranged in front of the lens system 8, that is, on the object side. In this case, the filter includes, for example, a light absorber 10 and a transparent dielectric substrate supporting the light absorber 10. If a rigid substrate such as a glass substrate is used as the transparent dielectric substrate, the filter can be expected to function as a protective filter for protecting the imaging device and the lens system from the outside.

[0176] Figure 4B 6b is a diagram showing another example of an imaging device. The imaging device 6b is configured similarly to the imaging device 6a except for the parts specifically described. Figure 4B As shown, in the imaging device 6a, a light absorber 10 is arranged on the surface of a part of the lens 8a included in the lens system 8. For example, the above-mentioned light absorbing composition can be applied to the surface of the lens 8a and cured, and the light absorber 10 can be arranged in a manner to form an interface with the lens 8a. Thus, even if a light absorbing filter is not provided separately from the lens system 8, the lens system 8 can have the desired light shielding property, and thus a significant simplification of the assembly or manufacture of the imaging device can be expected. The lens 8a in which such a light absorber 10 is integrally formed, or the lens system including such a lens 8a, can be circulated. An anti-reflection film or a reduced reflection film can also be formed on the surface of the light absorber 10. Thus, the reflected light from the surface of the light absorber 10 is reduced, and the transmitted light in the visible light region is easily increased. In the imaging device 6b, the configuration of the light absorber 10 is not limited to Figure 4B Configuration shown.

[0177] In the lens system of the camera device, a group of lenses formed by bonding the surfaces of two or more lenses to each other is sometimes included. In order to bond the lenses to each other, an adhesive or a curable resin can be used. Although not shown in the figure, the above-mentioned light absorbing composition can also be used as an adhesive for bonding the lenses to each other. In this case, the light absorber 10 is not easily affected by the external environment of the lens system, and it is expected to protect the light absorber 10 or the components contained in the light absorber 10. If the light absorbing composition is prepared in a manner that the refractive index of the light absorber 10 and the lens is roughly the same, the reflection at the interface between the light absorber 10 and the lens can be significantly reduced, and the advantage of not requiring an anti-reflection coating can be obtained.

[0178] Example

[0179] The present invention will be described in more detail by way of examples. It should be noted that the present invention is not limited to the following examples.

[0180] <Example 1>

[0181] 4.500 g of cupric acetate monohydrate was mixed with 240 g of tetrahydrofuran (THF) and stirred for 3 hours to obtain liquid (1-A) as a cupric acetate solution. Next, 40 g of THF was added to 0.610 g of phenylphosphonic acid and stirred for 30 minutes to obtain liquid (1-B). 40 g of THF was added to 3.660 g of 4-bromophenylphosphonic acid and stirred for 30 minutes to obtain liquid (1-C). 40 g of THF was added to 0.758 g of n-butylphosphonic acid and stirred for 30 minutes to obtain liquid (1-D). Liquid (1-B), liquid (1-C) and liquid (1-D) were mixed in liquid (1-A), and 4.00 g of n-hexadecyltrimethoxysilane as a trifunctional alkoxysilane and 2.78 g of tetraethoxysilane as a tetrafunctional alkoxysilane were further added, and stirred for 1 minute to obtain liquid (1-E). Next, 40 g of toluene was added to the liquid (1-E), and the mixture was stirred at room temperature for 1 minute to obtain liquid (1-F). The liquid (1-F) was placed in a flask, and while being heated with an oil bath (manufactured by Tokyo Rikakki Co., Ltd., model: OSB-2100), it was treated with a rotary evaporator (manufactured by Tokyo Rikakki Co., Ltd., model: N-1110SF) to react and remove THF. The set temperature of the oil bath was adjusted to 85°C. Then, the treated liquid was taken out from the flask. In this way, a light-absorbing composition (1-G) of Example 1 as a liquid light-absorbing composition containing a light-absorbing compound containing phosphonic acid and a copper component and a silicon-containing compound containing n-hexadecyl was obtained. The amount (content) of each compound added in the preparation of the light-absorbing composition of Example 1 is shown in Table 1. Table 1 also shows the amount (content) of each compound added in the preparation of the light-absorbing composition of other Examples and Comparative Examples.

[0182] A coating of the light-absorbing composition (1-G) is formed on one main surface of a borosilicate glass (manufactured by SCHOTT, product name: D263 T eco) having a size of 76 mm × 76 mm × 0.21 mm as a substrate using a dispenser. After the obtained coating is fully dried at room temperature, it is placed in an oven and heated in the range of room temperature to 85°C for about 6 hours to allow the reaction of the alkoxysilane to proceed fully and the organic solvent contained in the light-absorbing composition (1-G) to volatilize. Thereafter, the coating is further placed in an environment of a temperature of 85°C and a relative humidity of 85% for 8 hours for post-curing to complete the reaction. In this way, the light absorber of Example 1 is obtained. In addition, an optical filter of Example 1 in which the light absorber of Example 1 is arranged on a substrate is obtained.

[0183] The haze of the light absorber of Example 1 was measured using a haze meter HM-65L2 manufactured by Murakami Color Research Laboratory Co., Ltd. in accordance with Japanese Industrial Standard JIS K7136: 2000. As shown in Table 2, the haze value of the light absorber of Example 1 was 0.19%. In Table 2, the haze values ​​of the light absorbers of other Examples and Comparative Examples are shown except for the cases not measured.

[0184] The thickness of the light absorber of Example 1 was measured using a laser displacement meter LK-H008 manufactured by KEYENCE Corporation. As shown in Table 2, the thickness of the light absorber of Example 1 was 97 μm. Table 2 shows the thickness of the light absorbers of other Examples and Comparative Examples except for those not measured.

[0185] The transmission spectrum of the light absorber of Example 1 at an incident angle of 0° was measured using a UV-visible near-infrared spectrophotometer V-770 with a transmission light measurement accessory manufactured by JASCO Corporation. Unless otherwise specified, the transmission spectrum was measured by adjusting the temperature of the surrounding environment of the filter to 22°C to 25°C. In this measurement, the measurement accessory was replaced with a reflected light measurement accessory, and the reflection spectrum of the light absorber of Example 1 at an incident angle of 5° was measured. Unless otherwise specified, the reflection spectrum was measured by setting the temperature of the surrounding environment of the filter to 22°C to 25°C. Figure 5A The transmission spectrum of the light absorber of Example 1 is shown in FIG. Figure 5B Table 2 shows the characteristic values ​​of the optical absorber under various optical conditions at an incident angle of 0°. Table 3 shows the η obtained by dividing the optical density at a specific wavelength by the thickness of the optical absorber. λ Tables 2 and 3 show the characteristic values ​​related to the transmittance or reflectance of the light absorbers of other embodiments and comparative examples and η λ The value of .

[0186] <Examples 2 to 14>

[0187] The light absorbers of Examples 2 to 12 were prepared by the same method and conditions as in Example 1 except that the required compounds and the amounts thereof were changed as shown in Table 1A. In addition, the light absorbers of Examples 13 and 14 were prepared by the same method and conditions as in Example 1 except that the required compounds and the amounts thereof were changed as shown in Table 1B. The results of measuring or calculating the characteristic values ​​of each light absorber are shown in Tables 2 and 3. The transmission spectrum and reflection spectrum of the light absorber of Example 2 are shown in Tables 2 and 3, respectively. Fig. 6A and Figure 6B The transmission spectrum and reflection spectrum of the light absorber of Example 3 are shown in Fig. 7A and Figure 7B The transmission spectrum of the light absorber of Example 8 is shown in Figure 8 The transmission spectrum of the light absorber of Example 13 is shown in Fig. 9 The transmission spectrum of the light absorber of Example 14 is shown in Fig.10 .

[0188] <Example 15>

[0189] 0.1 g of a surface antifouling coating agent (manufactured by Daikin Industries, Ltd., product name: OPTOOL DSX, concentration of active ingredient: 20% by mass) and 19.9 g of a hydrofluoroether-containing liquid (manufactured by 3M, product name: Novec 7100) were mixed and stirred for 5 minutes to prepare a fluorine treatment agent (concentration of active ingredient: 0.1% by mass). The fluorine treatment agent was applied to one main surface of a borosilicate glass (manufactured by SCHOTT, product name: D263 T eco) having a size of 76 mm × 76 mm × 0.21 mm. Thereafter, the glass substrate was placed at room temperature for 24 hours to dry the coating of the fluorine treatment agent, and then the glass surface was gently wiped with a dust-free cloth containing Novec 7100 to remove excess fluorine treatment agent. A fluorine treatment substrate was prepared in this way.

[0190] The light absorbing composition of Example 15 was prepared by the same method and conditions as in Example 1 except that the required compounds and the addition amounts thereof were changed as described in Table 1. A light absorber was prepared on a fluorine-treated substrate in the same manner as in Example 1 except that the light absorbing composition of Example 15 was used instead of the light absorbing composition of Example 1 and the above-mentioned fluorine-treated substrate was used instead of the substrate. Next, the light absorber was peeled off from the fluorine-treated substrate to obtain a film-like light absorber of Example 15 as an optical filter of Example 15.

[0191] Tables 2 and 3 show the results of measuring or calculating the characteristic values ​​of the optical filter of Example 15.

[0192] <Example 16>

[0193] 4.500g of cupric acetate monohydrate was mixed with 240g of tetrahydrofuran (THF) and stirred for 3 hours to obtain a cupric acetate solution. Then, 2.400g of Plysurf A208N (made by Daiichi Kogyo Seiyaku Co., Ltd.) as a phosphate compound was added to the obtained cupric acetate solution and stirred for 30 minutes to obtain liquid (16-A). Then, 40g of THF was added to 2.800g of n-butylphosphonic acid and stirred for 30 minutes to obtain liquid (16-B). Liquid (16-A) and liquid (16-B) were mixed and stirred for 1 minute to obtain liquid (16-C). Then, 120g of toluene was added to the liquid (16-C) and stirred at room temperature for 1 minute to obtain liquid (16-D). The liquid (16-D) was placed in a flask and desolvated using a rotary evaporator (Tokyo Rikakki Co., Ltd., model: OSB-2100) while being heated in an oil bath (manufactured by Tokyo Rikakki Co., Ltd., model: N-1110SF). The set temperature of the oil bath was adjusted to 105° C. Then, the desolvated liquid was taken out from the flask. In this way, a liquid composition (16-E) in which a light-absorbing compound containing a phosphonic acid and a copper component was dispersed was obtained.

[0194] 7.54 g of a silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KR-300), 0.18 g of a catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., product name: CAT-AC), 9.74 g of methyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KBE-13) as a trifunctional alkoxysilane, 5.68 g of tetraethoxysilane (special grade manufactured by Kishida Chemical Co., Ltd.) as a tetrafunctional alkoxysilane, and 5.70 g of dimethyldiethoxysilane (DMDES) (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KBE-22) as a difunctional alkoxysilane were mixed and stirred for 30 minutes to obtain a prepared liquid curable resin (16-F). Furthermore, the above-mentioned liquid composition (16-E) and the liquid curable resin (16-F) were mixed and stirred for 30 minutes to prepare a light absorbing film composition (16-G).

[0195] The light-absorbing film composition (16-G) was applied to the 80 mm × 80 mm area of ​​the center of the fluorine-treated substrate prepared in the same manner as in Example 15 using a dispenser to form a coating. The obtained coating was fully dried at room temperature, and then placed in an oven and heated in the range of room temperature to 85°C to fully react the alkoxysilane and volatilize the organic solvent contained in the light-absorbing film composition (16-G). After that, the film was further placed in an environment of a temperature of 85°C and a relative humidity of 85% for 24 hours for post-curing to complete the reaction and prepare a light absorber on the fluorine-treated substrate. Next, the light absorber was peeled off from the fluorine-treated substrate to obtain a film-like light-absorbing substrate (16-H). Fig.11AThe transmission spectrum of the light absorbing substrate (16-H) is shown in Tables 2 to 4. The characteristic values ​​that can be seen from the transmission spectrum and the thickness of the film-like light absorbing substrate (16-H) are shown in Tables 2 to 4.

[0196] The light-absorbing composition of Example 16 was prepared by the same method and conditions as in Example 1, except that the required compounds and the amounts added were changed as described in Table 1. The optical filter of Example 16 having two light-absorbing layers was prepared by the same method and conditions as in Example 1, except that the light-absorbing composition of Example 16 was used instead of Example 1 and the light-absorbing substrate (16-H) was used as the substrate. Fig. 11B TABLE 2 shows the transmission spectrum of the optical filter of Example 16. Tables 2 and 3 show the results of measuring or calculating the characteristic values ​​of the optical filter of Example 16.

[0197] <Comparative Examples 1 to 3>

[0198] Light absorbers of Comparative Examples 1 to 3 were prepared by the same method and conditions as in Example 1 except that the necessary compounds and the amounts added were changed as described in Table 1. Fig.12 ] The transmission spectrum of the optical filter of Comparative Example 3 is shown in Tables 2 and 3. The measurement results and calculation results of each characteristic value that can be measured or calculated for the light absorbers of Comparative Examples 1 to 3 are shown.

[0199] The light absorbing composition of Comparative Example 1 had significant turbidity, and a transparent filter could not be produced. In Comparative Example 1, the carbon number of the alkyl group directly bonded to the silicon atom in the added trifunctional alkoxysilane was as small as 6, so it is estimated that the aggregation inhibition effect of the generated copper phosphate compound was insufficient. Therefore, in Comparative Example 2, the amount of the trifunctional alkoxysilane added was increased, but significant turbidity still occurred. Furthermore, in Comparative Example 3, in which the amount of the trifunctional silane added was greatly increased, a filter could be produced. However, as Fig.12 As shown in the figure, the transmittance of the filter of Comparative Example 3 in the visible light region is low, and the thickness of the light absorber in the filter of Comparative Example 3 is 157 μm. In addition, the haze of the light absorber of Comparative Example 3 is also very large, 12.96, and a filter with good characteristics cannot be obtained. These results suggest that when the carbon number of the alkyl group of the trifunctional straight-chain alkylsilane is less than 10, the aggregation inhibition effect of copper phosphite is not sufficient, and it is difficult to produce a filter with good optical characteristics.

[0200] <Example 17>

[0201] (Preparation of liquid precursor for forming antireflective film)

[0202] 0.87 g of tetraethoxysilane (TEOS) as a tetrafunctional silane, 1.33 g of methyltriethoxysilane (MTES) as a trifunctional silane, 0.80 g of 0.3 wt % formic acid, 3.70 g of a sol containing hollow silica particles (manufactured by JGC Catalysts & Chemicals Co., Ltd., product name: Thrulya 4110, silica solid content: about 25 wt %), and 27.3 g of ethanol were mixed and reacted at 30° C. for 1 hour and then at 35° C. for 2 hours to prepare a liquid precursor A for forming an antireflection film (hereinafter referred to as a liquid composition A for forming an antireflection film).

[0203] (Production of Filter with Anti-reflection Film)

[0204] On one side of the filter produced by the same conditions and method as in Example 15, the coating amount and coating conditions are adjusted so that the film thickness after drying and curing becomes 120 nm, and the liquid composition A for forming an anti-reflection film is coated. A spin coater is used for coating, and the rotation speed and rotation time are also adjusted. The filter coated with the liquid composition A for forming an anti-reflection film on one side is allowed to stand for about 1 minute for initial drying. Furthermore, the liquid composition A for forming an anti-reflection film is also coated on the other side of the filter under the same conditions and method. The filter with the anti-reflection film forming composition A on both sides that has been initially dried in this way is allowed to stand in an oven heated to an internal temperature of 85°C for 1 hour to react and cure the composition, thereby producing the filter of Example 17. The filter has anti-reflection films on both sides. The transmission spectrum of the filter of Example 17 is shown in FIG. Fig.13 Table 5 shows the characteristic values ​​and calculated values ​​based on the transmission spectrum, and Table 6 shows the values ​​obtained by dividing the optical density OD value at each wavelength λ by the thickness of the light absorber.

[0205] <Example 18>

[0206] (Preparation of liquid precursor for forming antireflective film)

[0207] 0.65 g of tetraethoxysilane (TEOS), 1.50 g of methyltriethoxysilane (MTES), 0.80 g of 0.3 wt % formic acid, and 27.3 g of ethanol were mixed and reacted at 30° C. for 1 hour and further at 35° C. for 2 hours. Thus, a composition B for forming an antireflective film was prepared.

[0208] (Production of Filter with Anti-reflection Film)

[0209] On one side of the filter prepared by the same conditions and method as in Example 15, the coating amount and coating conditions are adjusted so that the film thickness after drying and curing becomes 250nm, and the liquid composition B for forming an anti-reflection film is coated. A spin coater is used for coating, and the rotation speed and rotation time are also adjusted. The filter coated with the liquid composition B for forming an anti-reflection film on one side is left to stand for about 1 minute for initial drying. Furthermore, the liquid composition B for forming an anti-reflection film is also coated on the other side of the filter by the same conditions and method. The filter with the anti-reflection film forming composition B on both sides that has been initially dried in this way is left to stand in an oven heated to an internal temperature of 85°C for 1 hour to react and cure the composition. Next, for the filter having a layer formed by curing the reflection film forming composition B on both sides, the coating amount and coating conditions are adjusted so that the film thickness after drying and curing becomes 90nm, and the liquid composition A for forming an anti-reflection film is coated on one side. A spin coater is used for coating, and the rotation speed and rotation time are also adjusted. The filter coated with the anti-reflection film forming liquid composition A on one side was allowed to stand for about 1 minute for initial drying. Furthermore, the anti-reflection film forming liquid composition A was also applied to the other side of the filter under the same conditions and method. The filter with the anti-reflection film forming composition A on both sides that was initially dried was allowed to stand in an oven heated to an internal temperature of 85°C for 1 hour to react and cure the composition, thereby preparing a filter of Example 18. This filter has anti-reflection films on both sides. The transmission spectrum of the filter of Example 18 is shown in FIG. Fig.14 Table 5 shows the characteristic values ​​and calculated values ​​based on the transmission spectrum, and Table 6 shows the values ​​obtained by dividing the optical density OD value at each wavelength λ by the thickness of the light absorber.

[0210]

[0211]

[0212]

[0213]

[0214]

[0215]

[0216] [Table 6]

[0217]

Claims

1. A light absorbing composition comprising: At least one selected from the group consisting of an alkoxysilane containing a group having 10 or more carbon atoms, a hydrolyzate of the alkoxysilane, and a polymer of the hydrolyzate of the alkoxysilane; and Light absorbing compounds.

2. The light-absorbing composition according to claim 1, wherein The light absorbing compound includes a phosphoric acid compound and a copper component.

3. The light-absorbing composition according to claim 1, wherein The light absorbing compound comprises phosphonic acid and copper components.

4. The light-absorbing composition according to any one of claims 1 to 3, wherein The light absorber as a cured product of the light absorbing composition satisfies the following conditions (i) and (ii), (i) The value obtained by dividing the optical density OD at wavelength λ by the thickness of the light absorber is expressed as η λ [μm -1 ], 0.009≤η 380 and 0.008≤η 750 , (ii) The average value of the transmittance in the wavelength range of 460 nm to 600 nm is represented as T A 460-600 When 80%≤T A 460-600 .

5. The light-absorbing composition according to any one of claims 1 to 4, wherein The light absorbing composition does not contain phosphate esters.

6. A light absorber having an average value T A 460-600 More than 80%, The average value T A 460-600 is the average value of the transmittance in the wavelength range of 460 nm to 600 nm of the transmission spectrum obtained when light is incident on the light absorber at an incident angle of 0°, The value obtained by dividing the optical density OD at the wavelength λ of the light absorber by the thickness of the light absorber is expressed as η. λ [μm -1 ], satisfying 0.009≤η 380 and 0.008≤η 750 conditions. The light absorber according to claim 6 , having a haze of less than 0.2%.

8. The light absorber according to claim 6 or 7, wherein: Average value T A 300-380 and the average value T A 750-1100 Meet T A 300-380 ≤1.5% and T A 750-1100 ≤2.0% condition, The average value T A 300-380 is the average value of the transmittance in the wavelength range of 300nm to 380nm of the transmission spectrum, The average value T A 750-1100 It is the average value of the transmittance in the wavelength range of 750nm to 1100nm of the transmission spectrum. 9 . An optical filter comprising the light absorber according to claim 6 . 10 . The optical filter according to claim 9 , comprising the light absorber and an antireflection film provided on a surface of the light absorber.

11. The optical filter according to claim 10, wherein The antireflection film comprises one or more layers selected from the group consisting of the following (a), (b1), (b2) and (c), (a) a layer comprising silsesquioxane and silicon dioxide; (b1) a layer comprising silsesquioxane, silica and hollow particles; (b2) a layer comprising silsesquioxane, silica and solid particles; (c) comprising a material selected from the group consisting of SiO2, TiO2, Ta2O3, SnO2, In2O3, Nb2O5, Si3N4, TiN x and MgF2.

12. The optical filter according to claim 11, wherein The layer (b1) includes hollow particles having a refractive index of 1.02 to 1.

50.

13. The optical filter according to claim 11 or 12, wherein: The layer of (c) is composed of one layer or two or more layers, and the two or more layers are composed of different materials.

14. The optical filter according to any one of claims 11 to 13, wherein The antireflection film includes the layer of (b1) and the layer of (b2), The refractive index of the layer (b2) is higher than the refractive index of the layer (b1).

15. The optical filter according to any one of claims 11 to 14, wherein The layer (b1) includes hollow particles having a refractive index of 1.02 to 1.

50.

16. The optical filter according to any one of claims 11 to 15, wherein The layer of (b2) comprises solid particles having a refractive index of 1.25 to 2.

75. 17 . An ambient light sensor comprising the light absorber according to claim 6 . 18 . An imaging device comprising the light absorber according to claim 6 .

19. A method for producing a light absorbing composition, comprising: preparing a light absorbing compound dispersion liquid in which a light absorbing compound including phosphonic acid and copper components is dispersed in a solvent; mixing the light absorbing compound dispersion with an alkoxysilane containing a group having 10 or more carbon atoms or a hydrolyzate of the alkoxysilane; and A portion of the solvent is removed from the light absorbing compound dispersion.

20. The method for producing a light-absorbing composition according to claim 19, wherein: The cured product of the light absorbing composition satisfies the following conditions (i) and (ii), (i) The value obtained by dividing the optical density OD at wavelength λ by the thickness of the cured product is expressed as η λ [μm -1 ], 0.009≤η 380 and 0.008≤η 750 , (ii) The average value of the transmittance in the wavelength range of 460 nm to 600 nm is represented as T A 460-600 When 80%≤T A 460-600 .

21. A method for manufacturing a light absorber, comprising: The light absorbing composition applied on the surface of the substrate is cured to obtain a light absorbing body, The light absorbing composition comprises: a light absorbing compound comprising a phosphonic acid and a copper component; and at least one selected from the group consisting of an alkoxysilane containing a group having 10 or more carbon atoms, a hydrolyzate of the alkoxysilane, and a polymer of the hydrolyzate of the alkoxysilane, The light absorber has a thickness of 150 μm or less.

22. The method for producing a light absorber according to claim 21, wherein: The light absorber satisfies the following conditions (i) and (ii), (i) The value obtained by dividing the optical density OD at wavelength λ by the thickness of the light absorber is expressed as η λ [μm -1 ], 0.009≤η 380 and 0.008≤η 750 , (ii) The average value of the transmittance in the wavelength range of 460 nm to 600 nm is represented as T A 460-600 When 80%≤T A 460-600 .

23. An optical filter comprising: a light absorber; and an antireflection film provided on the surface of the light absorber, The optical filter satisfies the following conditions (I) and (II), (I) The value obtained by dividing the optical density OD at wavelength λ by the thickness of the light absorber is expressed as η 2-λ [μm -1 ], 0.009≤η 2-380 and 0.008≤η 2-750 , (II) The average value of the transmittance in the wavelength range of 460 nm to 600 nm is represented as T2 A 460-600 When 90%≤T2 A 460-600 .

24. The optical filter according to claim 23, which satisfies 0.020≤η 2-900 and 0.013≤η 2-1100 .

25. The optical filter according to claim 23 or 24, wherein The average value of the transmittance in the wavelength range of 300nm to 380nm is defined as T2 A 300-380 , the average value of the transmittance within the wavelength range of 750nm to 1100nm is set as T2 A 750-1100 When T2 A 300-380 ≤1.5% and T2 A 750-1100 ≤2.0%, The second ultraviolet cutoff wavelength at which the transmittance reaches 50% in the wavelength range of 350nm to 460nm is set to λ2 0 UV The second infrared cutoff wavelength at which the transmittance reaches 50% in the wavelength range of 600nm to 700nm is set to λ2 0 IR When 390nm≤λ2 0 UV ≤450nm and 600nm≤λ2 0 IR ≤680nm.

26. The optical filter according to any one of claims 23 to 25, wherein The antireflection film includes a layer containing silsesquioxane and silicon dioxide.

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