Light-absorbing composition, light absorber, optical filter, and imaging device

Abstract

The present invention provides a light-absorbing composition, a light absorber, an optical filter, an ambient light sensor, an imaging device, a method for manufacturing a light-absorbing composition, and a method for manufacturing a light absorber, all of which are advantageous in terms of thinness and optical properties. [Solution] 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 alkoxysilanes containing a group α-1 having 10 or more carbon atoms and hydrolysates 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 a light-absorbing composition, and a method for producing a light absorber. [Background technology]

[0002] In imaging devices or ambient light sensors using solid-state image sensors such as CCDs (Charge Coupled Devices) or CMOSs ​​(Complementary Metal Oxide Semiconductors), various optical filters are arranged in front of the solid-state image sensor. For example, in imaging devices, optical filters may be used to obtain images with good color reproduction. In ambient light sensors, optical filters may be used to adjust the sensing of ambient light.

[0003] Generally, solid-state image sensors have sensitivity across a wide wavelength range, from the ultraviolet to the infrared region. On the other hand, human visual sensitivity exists only in the visible light region, with wavelengths of approximately 380 nm to 780 nm. For this reason, a technique is known in which an optical filter is placed in front of the solid-state image sensor to block some infrared and ultraviolet light, in order to bring the spectral sensitivity of the solid-state image sensor in an imaging device closer to human visual sensitivity.

[0004] Among these, optical filters with a film or layer containing a light-absorbing agent are attracting attention. The transmittance characteristics of optical filters with a film containing a light-absorbing agent are less affected by the angle of incidence, so even when light is incident on the optical filter at an oblique angle in an imaging device, for example, color changes are minimal, color unevenness is minimal within the plane, and good images with good reproducibility can be obtained. In addition, since optical filters with a film containing a light-absorbing agent do not use a light-reflective film, the occurrence of ghosting or flare caused by multiple reflections due to light reflection can be suppressed, making it easier to obtain good images. Furthermore, optical filters with a film containing a light-absorbing agent are also advantageous in terms of miniaturization and thinning of imaging devices.

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

[0006] Patent Document 2 describes an optical filter having a light-absorbing layer that contains a light-absorbing agent formed by a predetermined phosphonic acid and copper ions, and does not contain a predetermined phosphate ester. Patent Document 2 explains that the predetermined phosphate ester is easily hydrolyzed and is not an optimal material from the viewpoint of weather resistance.

[0007] Patent Document 3 describes an optical filter equipped with a UV-IR absorbing layer containing a UV-IR absorbent formed by at least one acid, such as a phosphonic acid or a sulfonic acid, and copper ions, which is capable of absorbing ultraviolet and infrared rays. This optical filter has a haze value of 5% or less. Patent Document 3 explains that by incorporating such an optical filter containing a UV-IR absorbing layer into an imaging device, high-quality images can be obtained. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] International Publication No. 2020 / 071461 [Patent Document 2] International Publication No. 2019 / 093076 [Patent Document 3] International Publication No. 2019 / 208518 [Overview of the project] [Problems that the invention aims to solve]

[0009] The technologies described in Patent Documents 1 to 3 have room for reconsideration from the viewpoint of thinness and optical properties. Therefore, the present invention provides a light-absorbing compound that is advantageous from the viewpoint of thinness and optical properties. Furthermore, the present invention provides a light absorber that is advantageous from the viewpoint of thinness and optical properties. [Means for solving the problem]

[0010] The present invention At least one selected from the group consisting of an alkoxysilane containing a group having 10 or more carbon atoms, a hydrolysate of the alkoxysilane, and a polymer of the hydrolysate of the alkoxysilane, A light-absorbing compound, A light-absorbing composition is provided.

[0011] Furthermore, the present invention is It is a light absorber, Average value T A 460-600 It is over 80%, Said average value T A 460-600 This is the average value of the transmittance in the wavelength range of 460 nm to 600 nm of the transmission spectrum obtained by incidenting light on the light absorber at an incident angle of 0°. η is the value obtained by dividing the optical density OD of the light absorber at wavelength λ by the thickness of the light absorber. λ [μm -1 When expressed as ], 0.009≦η 380 and 0.008≦η 750 Meets the requirements, We provide light absorbers.

[0012] Furthermore, the present invention is An optical filter equipped with the above-mentioned light absorber is provided.

[0013] Furthermore, the present invention is An ambient light sensor equipped with the above-mentioned light absorber is provided.

[0014] Furthermore, the present invention is The present invention provides an imaging device equipped with the above-mentioned light absorber.

[0015] Further, the present invention includes preparing a light-absorbing compound dispersion in which a light-absorbing compound containing a phosphonic acid and a copper component 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 removing a part of the solvent from the light-absorbing compound dispersion, and provides a method for producing a light-absorbing composition.

[0016] Further, the present invention includes obtaining a light absorber by solidifying a light-absorbing composition coated on the surface of a substrate, wherein the light-absorbing composition includes a light-absorbing compound containing 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, and the light absorber has a thickness of 150 μm or less, and provides a method for producing a light absorber.

[0017] Further, the present invention provides an optical filter including a light absorber and an antireflection film provided on the surface of the light absorber, satisfying the following conditions (I) and (II): (I) When the value obtained by dividing the optical density OD at wavelength λ by the thickness of the light absorber is represented by η [μm 2-λ ], 0.009 ≦ η -1 and 0.008 ≦ η 2-380 ; 2-750 (II) When the average value of the transmittance in the wavelength range of 460 nm to 600 nm is represented by T2 A 460-600 A , 90% ≦ T2 460-600

Effects of the Invention

[0018] The above-mentioned light-absorbing compositions and light-absorbing materials are advantageous in terms of thinness and optical properties. [Brief explanation of the drawing]

[0019] [Figure 1A] Figure 1A is a cross-sectional view showing an example of an optical filter according to the present invention. [Figure 1B] Figure 1B is a cross-sectional view showing another example of an optical filter according to the present invention. [Figure 1C] Figure 1C is a cross-sectional view showing yet another example of an optical filter according to the present invention. [Figure 1D] Figure 1D is a cross-sectional view showing yet another example of an optical filter according to the present invention. [Figure 2] Figure 2 is a graph showing the transmission spectrum of an example of glass contained in a substrate. [Figure 3A] Figure 3A is a cross-sectional view showing an example of an ambient light sensor according to the present invention. [Figure 3B] Figure 3B is a cross-sectional view showing an example of a photoelectric conversion element according to the present invention. [Figure 4A] Figure 4A shows an example of an imaging device according to the present invention. [Figure 4B] Figure 4B shows another example of the imaging device according to the present invention. [Figure 5A] Figure 5A is a graph showing the transmission spectrum of the light absorber according to Example 1. [Figure 5B] Figure 5B is a graph showing the reflectance spectrum of the light absorber according to Example 1. [Figure 6A] Figure 6A is a graph showing the transmission spectrum of the light absorber according to Example 2. [Figure 6B] Figure 6B is a graph showing the reflectance spectrum of the light absorber according to Example 2. [Figure 7A] Figure 7A is a graph showing the transmission spectrum of the light absorber according to Example 3. [Figure 7B]Figure 7B is a graph showing the reflectance spectrum of the light absorber according to Example 3. [Figure 8] Figure 8 is a graph showing the transmission spectrum of the light absorber according to Example 8. [Figure 9] Figure 9 is a graph showing the transmission spectrum of the light absorber according to Example 13. [Figure 10] Figure 10 is a graph showing the transmission spectrum of the light absorber according to Example 14. [Figure 11A] Figure 11A is a graph showing the transmission spectrum of the substrate according to Example 16. [Figure 11B] Figure 11B is a graph showing the transmission spectrum of the optical filter according to Example 16. [Figure 12] Figure 12 is a graph showing the transmission spectrum of the optical filter according to Comparative Example 3. [Figure 13] Figure 13 is a graph showing the transmission spectrum of the optical filter according to Example 17. [Figure 14] Figure 14 is a graph showing the transmission spectrum of the optical filter according to Example 18. [Modes for carrying out the invention]

[0020] With the global proliferation of information terminals such as smartphones equipped with camera modules, there is a growing demand for thinner optical filters used in cameras or ambient light sensors. The optical filter described in Patent Document 1 has a thickness of 80 μm or less and a transmittance of 5% or less in the wavelength range of 750 nm to 1080 nm, but its light absorption characteristics in this wavelength range are not considered sufficient. For example, it is understood that it is difficult to achieve a transmittance of 1% or less in the wavelength range of 750 nm to 1080 nm with a thickness of about 110 μm. In other words, it is understood that it is difficult to achieve sufficient light absorption performance with a thickness of about 110 μm in an optical filter equipped with a light absorption layer containing copper phosphonate and an organic dye, even when using an organic dye in combination.

[0021] The optical filter described in Patent Document 2 is promising because it does not contain phosphate esters, but it cannot be said to have sufficient properties in terms of achieving both thinness and desired optical characteristics. In addition, because it does not contain phosphate esters, there is a possibility that some of the copper phosphonate may aggregate, reducing the transmittance in the visible range.

[0022] Patent Document 3 describes the copper content in the light-absorbing compound and the viscosity of the liquid light-absorbing composition that is a precursor to the UV-IR absorption layer. In the UV-IR absorption layer described in Patent Document 1, the haze value is at least 0.2%. If a haze lower than 0.2% can be achieved in a light-absorbing optical filter, the value of the optical filter can be further enhanced.

[0023] As a result of diligent research, the inventors have discovered a new light-absorbing compound that is advantageous in terms of achieving desired optical properties such as transmittance close to the human luminous efficiency curve and low haze, even when thin. In addition, they have completed a novel light absorber that is advantageous in terms of achieving desired optical properties such as transmittance close to the human luminous efficiency curve and low haze.

[0024] The following describes embodiments of the present invention. Note that the following description is illustrative and not limited to the embodiments described below.

[0025] The light-absorbing composition contains 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 alkoxysilanes containing a group α-1 having 10 or more carbon atoms, hydrolysates of the alkoxysilane, and polymers of the hydrolysates of the alkoxysilane. The hydrolysates of the alkoxysilane are silicon compounds having a silanol group (-Si-OH) produced by the hydrolysis of the alkoxysilane. The polymers of the hydrolysates of the alkoxysilane are compounds containing a siloxane bond (-O-Si-O-) formed by the condensation polymerization of a portion of the hydrolysate. The presence of the silicon-containing compound α is thought to make the group α-1 more likely to act as a steric hindrance in the aggregation of the light-absorbing compound. For this reason, for example, when a light-absorbing compound containing a complex structure is formed, the formation of aggregates of the light-absorbing compound is easily prevented. As a result, the light-absorbing compound is homogeneously dispersed in the light-absorbing composition, and desired optical properties such as a transmission spectrum corresponding to the human luminous efficiency curve and low haze are easily achieved in the light absorber made using the light-absorbing composition. Alkoxysilanes containing the α-1 group are represented, for example, by the following formula (1). In formula (1), n ​​is 1, 2, or 3, and R 11 R is a group containing at least carbon atoms (C) and hydrogen atoms (H), 11 At least one of them is an α-1 group having 10 or more carbon atoms. 12 R is a group containing at least carbon atoms (C) and hydrogen atoms (H), 11 It may be the same as R 11 It may be different from that. R 11 4-n Si(OR 12 ) n Formula (1)

[0026] Light-absorbing compounds are not limited to specific compounds. For example, a light-absorbing compound may be a compound containing phosphonic acid and a copper component, a compound containing a phosphate ester and a copper component, or a compound containing another phosphate compound and a copper component. Examples of other phosphate compounds include phosphoric acid, phosphorous acid, and phosphinic acid. Compounds containing phosphoric acid are Mx Cu y PO z The phosphate-copper complex may be represented as (where M is optional or represents a metal element other than Cu, and x, y, and z are real numbers). Furthermore, when a light-absorbing compound is formed containing a phosphate compound such as phosphonic acid, phosphate ester, or phosphoric acid, and a copper component, the copper component, in particular, a portion of the anion of the compound that serves as the raw material for the copper ion, may be included in the light-absorbing compound. For example, when the raw material for the copper component is copper acetate, a portion of the acetic acid component may be included in the light-absorbing compound, and when the raw material for the copper component is copper benzoate, a portion of the benzoic acid component may be included in the light-absorbing compound. The fact that the light-absorbing compound contains a phosphate compound such as phosphonic acid, phosphate ester, or phosphoric acid, and a copper component does not preclude the inclusion of other compounds or elements. The light-absorbing compound may be a compound containing sulfonic acid and a copper component, a metal oxide, or an organic dye. Examples of metal oxides are tungsten oxide, indium tin oxide (ITO), and antimony tin oxide. Examples of organic pigments include diinmonium compounds, cyanine compounds, squarylium compounds, phthalocyanine compounds, and pyrrolopyrrole compounds.

[0027] The light-absorbing compounds are preferably compounds containing phosphonic acid and a copper component, compounds containing phosphate ester and a copper component, compounds containing phosphate and a copper component, compounds containing sulfonic acid and a copper component, or compounds formed as complexes of each of these compounds. In this case, the light-absorbing compounds tend to have a broad absorption band in the infrared region, making the light-absorbing composition promising as a filter material that exhibits shielding of light in a predetermined wavelength range solely through absorption.

[0028] In a light-absorbing composition, the above-mentioned compound may be used alone as the light-absorbing compound, or multiple types of compounds may be used in combination.

[0029] Phosphonic acid, phosphate ester, and phosphoric acid are all oxides containing a phosphorus atom (P) and an oxygen atom (O). These may coexist; for example, the light-absorbing compound may exist as a compound containing phosphonic acid, phosphate ester, and a copper component. Even when the light-absorbing compound is a complex containing phosphonic acid and a copper component, a phosphate ester may be added as a dispersant. In this case, the light-absorbing composition may contain a compound containing phosphonic acid, a phosphate ester, and a copper component. Copper(II) acetate or copper(II) benzoate can be a raw material for the copper component of the light-absorbing compound. In this case, the acetate component (CH3COO) contained in the raw material... - (or CH3COOH) or benzoic acid component (C6H5COO - A portion of (or C6H5COOH) may be coordinated in these light-absorbing compounds to a copper ion or a copper complex containing a copper component with a phosphorus compound such as phosphonic acid. Furthermore, the copper compound that serves as the raw material for the copper component may be a hydrate, and the raw material may contain water molecules.

[0030] When a light-absorbing compound contains a phosphonic acid, the phosphonic acid is not limited to a specific type. A phosphonic acid can be represented, for example, by the following formula (a). In formula (a), R1 is an alkyl group or a halogenated alkyl group in which at least one hydrogen atom in the alkyl group is substituted with a halogen atom. In this case, the transmission band of the light absorber made using the light-absorbing composition tends to extend to a wavelength of around 700 nm, and the light absorber tends to have the desired transmittance characteristics. A phosphonic acid represented by formula (a) is called an alkylphosphonic acid.

[0031] [ka]

[0032] Examples of alkylphosphonic acids include 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.

[0033] 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, an aryl halide in which at least one hydrogen atom of the aryl group is substituted with a halogen atom, a group in which at least one hydrogen atom of the aryl group is substituted with a nitro group, or a group in which at least one hydrogen atom of the aryl group is substituted with a hydroxyl group. An aryl group is, for example, a phenyl group. An aryl halide is, for example, a phenyl halide. This makes it easier for the light absorber made using the light-absorbing composition to have the desired transmittance characteristics. The phosphonic acid represented by formula (b) is called an arylphosphonic acid.

[0034] [ka]

[0035] Examples of arylphosphonic acids include phenylphosphonic acid, bromophenylphosphonic acid, benzylphosphonic acid, fluorophenylphosphonic acid, iodophenylphosphonic acid, nitrophenylphosphonic acid, hydroxyphenylphosphonic acid, tolylphosphonic acid, xylylphosphonic acid, and naphthylphosphonic acid.

[0036] 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 types of alkylphosphonic acid, and the light-absorbing compound may contain one or more types of arylphosphonic acid. In the light-absorbing compound, each of the alkylphosphonic acid and arylphosphonic acid may be bonded to a copper component.

[0037] When a light-absorbing compound contains a copper component, the copper component is a concept that encompasses copper ions, copper complexes, and copper-containing compounds. The copper component may have good absorption characteristics for some light belonging to the near-infrared region and high transmittance in the visible light region with wavelengths from 450 nm to 680 nm. For example, although details are omitted, divalent copper ions (Cu) 2+ In the case of a six-coordinate complex structure, light of a corresponding energy wavelength is absorbed in relation to electron transitions between d orbitals with different energy levels. Divalent copper ions absorb light in a relatively broad wavelength range belonging to the infrared spectrum, and are therefore considered to exhibit a highly valuable light-absorbing function as filters used in the field of digital photography. The width of the absorption band and the intensity of absorption are largely determined by the structure or properties of the ligands that coordinate to the copper ion. For these reasons, it is desirable to use light absorbers or optical filters containing phosphorus compounds such as phosphonic acids and phosphate esters coordinated to copper ions for correction of luminous sensitivity.

[0038] The source of the copper component in light-absorbing compounds is not limited to a specific substance. Examples of copper component sources include anhydrous or hydrated copper salts of organic acids such as copper acetate, copper benzoate, copper pyrophosphate, and copper stearate, or mixtures thereof. Among these, copper acetate or copper benzoate are preferably used. These copper salts may be used individually, or multiple copper salts or mixtures thereof may be used.

[0039] The light-absorbing composition may contain a silicon-containing compound β, which is at least one selected from the group consisting of alkoxysilanes represented by the following formula (2) and hydrolysates of said alkoxysilanes. In formula (2), m is an integer of 3 or 4, and R 01 and R 02 They may be the same or different, R 01 and R 02 Each of these groups contains at least a carbon atom (C) and a hydrogen atom (H). The alkoxysilane represented by formula (2) is a trifunctional alkoxysilane or a tetrafunctional alkoxysilane. The light-absorbing composition may contain only a trifunctional alkoxysilane as the silicon-containing compound β, or only a tetrafunctional alkoxysilane, or both a trifunctional alkoxysilane and a tetrafunctional alkoxysilane. The silicon-containing compound may be an alkoxysilane as a monomer, or a compound obtained by hydrolysis of part of the alkoxysilane. The silicon-containing compound β may contain a compound containing a siloxane bond obtained by condensation polymerization of part of the hydrolysis product of the alkoxysilane. R 01 4-m Si(OR 02 ) m Formula (2)

[0040] In a light-absorbing composition, the inclusion of a silicon-containing compound β represented by formula (2) facilitates the formation of a network when the light-absorbing composition is solidified. For example, when producing a light absorber using a light-absorbing composition, siloxane bonds (-Si-O-Si-) are formed by processing the composition to ensure sufficient hydrolysis and polymerization reactions of the alkoxysilane. This makes the light absorber more resistant to moisture. In addition, the light absorber exhibits good heat resistance. This is because siloxane bonds have higher bond energy and are more chemically stable than bonds such as -CC- and -CO- bonds, resulting in superior heat and moisture resistance. From the viewpoint of improving the density of the light absorber, the light-absorbing composition preferably contains a tetrafunctional alkoxysilane with m=4 in formula (2) as the silicon-containing compound β. 01and R 02 This group may be a hydrocarbon group having 1 to 8 carbon atoms, or a group containing an aryl group. Furthermore, in formula (2), the inclusion of a trifunctional alkoxysilane with m=3 in addition to a tetrafunctional alkoxysilane with m=4 can provide flexibility to the light absorber.

[0041] As described above, the light-absorbing composition includes silicon-containing compound α as one of the silicon-containing compounds. The group α-1 in 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 or may not have a branched carbon chain.

[0042] Group α-1 may have a phenyl group, or it may have a substituted phenyl group in which at least one hydrogen atom in the phenyl group is replaced by a halogen atom, a nitro group, or an amino group. Group α-1 may have reactive functional groups such as a vinyl group, an epoxy group, a carbonyl group, an ester group, an amino group, a nitrile group, and a hydroxyl group.

[0043] The silicon-containing compound α may be a trifunctional alkoxysilane, a difunctional alkoxysilane, or a hydrolysate of these alkoxysilanes. These compounds facilitate the dispersion of light-absorbing compounds in the light-absorbing composition in a desired state and can impart predetermined flexibility and crosslinkability to polymers produced by the hydrolysis and condensation polymerization of tetrafunctional alkoxysilanes such as tetraethoxysilane (TEOS). This is advantageous from the viewpoint of improving the mechanical strength and weather resistance of light absorbers obtained using the light-absorbing composition.

[0044] When a light-absorbing composition contains a trifunctional alkoxysilane, a difunctional alkoxysilane, or a hydrolysate of these alkoxysilanes as the silicon-containing compound α, it is possible to reduce the need to include compounds that impart dispersibility, such as polyoxyalkyl phosphate esters, in the light-absorbing composition.

[0045] In a light-absorbing composition, the silicon-containing compound α may contain only at least one selected from the group consisting of trifunctional alkoxysilanes and hydrolysates of trifunctional alkoxysilanes. The silicon-containing compound α may contain only at least one selected from the group consisting of difunctional alkoxysilanes and hydrolysates of difunctional alkoxysilanes. In a light-absorbing composition, the silicon-containing compound α, which is a difunctional alkoxysilane, a trifunctional alkoxysilane, or a hydrolysate thereof, may be included together with a tetrafunctional alkoxysilane, a trifunctional alkoxysilane, or a hydrolysate thereof represented by formula (2).

[0046] The light-absorbing composition does not necessarily have to contain a curable resin. This is because the silicon-containing compound α polymerizes in such a way that the light-absorbing composition solidifies while the light-absorbing compound is present in the desired state, or the silicon-containing compound β also functions as a network former and polymerizes in such a way that the light-absorbing composition solidifies. If the light-absorbing composition contains a tetrafunctional alkoxysilane contained in the alkoxysilane represented by formula (2), an improvement in the density or hardness of the light absorber can be expected. The alkoxysilanes represented by formulas (1) and (2) can be solidified by increasing their molecular weight through hydrolysis and condensation polymerization of siloxane bonds using the so-called sol-gel method. Alternatively, the light-absorbing composition may solidify as a dry gel when the solvent or by-products contained in the light-absorbing composition containing the alkoxysilane or its hydrolysate are removed by evaporation or other means. It is not possible to definitively determine which effect is dominant, but it is thought that various effects and processes are involved, including the dispersion effect of the light-absorbing compound.

[0047] The content of silicon-containing compound α in a light-absorbing composition is not limited to a specific value. For example, if the light-absorbing compound contains a copper component, the ratio of the amount of silicon atoms in silicon-containing compound α to the amount of copper component is r. CS The ratio is 0.30 or higher on a molar basis. In this case, aggregates of light-absorbing compounds are less likely to form in the light-absorbing composition. Ratio r CS The ratio is preferably 0.35 or higher, and more preferably 0.40 or higher. CS For example, the ratio is 2.80 or less. In this case, it is easier to reduce the thickness of the light absorber obtained using the light-absorbing composition, which contributes to reducing the height of the element or device equipped with the light absorber. CS It is preferably 2.50 or less, and more preferably 2.20 or less.

[0048] When a light-absorbing composition contains alkoxysilane, a humidification treatment may be performed when curing the light-absorbing composition to produce a light absorber. In the humidification treatment, the light-absorbing composition is exposed to an atmosphere with relatively high humidity. It is thought that the humidification treatment promotes the hydrolysis of the alkoxysilane contained in the light-absorbing composition or light absorber due to the moisture in the atmosphere, thereby promoting the formation of siloxane bonds. Through the humidification treatment, a hard and dense light absorber can be formed without the particles containing the light-absorbing compound agglomerating.

[0049] Alkoxysilanes containing the α-1 group are not limited to specific alkoxysilanes. Examples of alkoxysilanes containing the α-1 group include 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 α-1 group include n-decyltriethoxysilane, n-undecyltriethoxysilane, n-dodecyltriethoxysilane, n-tridecyltriethoxysilane, n-tetradecyltriethoxysilane, n-pentadecyltriethoxysilane, n-hexadecyltrimethoxysilane, n-heptadecyltrimethoxysilane, n-octadecyltrimethoxysilane, n-nonadecyltrimethoxysilane, and n-eicosyltrimethoxysilane. Further examples of alkoxysilanes containing group α-1 include n-decylmethyldiethoxysilane, n-undecylmethyldiethoxysilane, n-dodecylmethyldiethoxysilane, n-tridecylmethyldiethoxysilane, n-tetradecylmethyldiethoxysilane, n-pentadecylmethyldiethoxysilane, n-hexadecylmethyldiethoxysilane, and n-heptadecylmethyldiethoxysilane. These include lan, n-octadecylmethyldiethoxysilane, n-nonadecylmethyldiethoxysilane, and n-eicosylmethyldiethoxysilane. Furthermore, examples of alkoxysilanes containing reactive functional groups include 8-glycidoxyoctyltrimethoxysilane and 8-methacryloxyoctyltrimethoxysilane.

[0050] The light-absorbing composition may contain alkoxysilanes other than alkoxysilanes containing the α-1 group. The light-absorbing composition may also contain a silicon-containing compound β, which is at least one compound selected from the group consisting of alkoxysilanes represented by formula (2), hydrolysates of the alkoxysilane, and condensed polymers of the hydrolysates of the alkoxysilane. The alkoxysilane represented by formula (2) is not limited to a specific alkoxysilane. Examples of alkoxysilanes represented by formula (2) include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, methyltrimethoxysilane, methyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, butyltriethoxysilane, butyltrimethoxysilane, phenyltrimethoxysilane, and phenyltriethoxysilane.

[0051] 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, xylenes, or cyclic compounds. Examples of alcohols include methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, 2-butanol, t-butanol, n-pentanol, i-pentanol, 2-methylbutanol, 2-pentanol, t-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-nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, and diacetone alcohol. Examples of cyclic compounds include dichlorobenzene, heptanone, cyclopentanone, cyclohexanone, cyclohexane, dimethylformamide, dimethylacetamide, toluene, tetrahydrofuran (THF), and oxetane.

[0052] The light-absorbing composition may contain a phosphate ester. For example, if the light-absorbing compound contains phosphonic acid, the phosphate ester is a compound that contains phosphorus and oxygen atoms, similar to phosphonic acid, so good compatibility between the phosphate ester and phosphonic acid is expected. The phosphate ester may function as a dispersant for the light-absorbing compound, or it may exist in a state where a portion of it has reacted with a metal component such as copper ions to form a compound. For example, a portion of the phosphate ester may be coordinated to the light-absorbing compound, or a portion of it may form a complex with the copper component of the light-absorbing compound. In this case, the compound containing the phosphate ester and the copper component can also absorb light of a predetermined wavelength.

[0053] Phosphate esters are not limited to specific phosphate esters. Phosphate esters, for example, have a polyoxyalkyl group. Examples of such phosphate esters include Prisurf A208N: polyoxyethylene alkyl (C12, C13) ether phosphate ester, Prisurf A208F: polyoxyethylene alkyl (C8) ether phosphate ester, Prisurf A208B: polyoxyethylene lauryl ether phosphate ester, Prisurf A219B: polyoxyethylene lauryl ether phosphate ester, Prisurf AL: polyoxyethylene styrene-phenyl ether phosphate ester, Prisurf A212C: polyoxyethylene tridecyl ether phosphate ester, or Prisurf A215C: polyoxyethylene tridecyl ether phosphate ester. All of these are products manufactured by Daiichi Kogyo Seiyaku Co., Ltd. In addition, examples of phosphate esters include NIKKOL DDP-2: polyoxyethylene alkyl ether phosphate ester, NIKKOL DDP-4: polyoxyethylene alkyl ether phosphate ester, or NIKKOL DDP-6: polyoxyethylene alkyl ether phosphate ester. All of these are products manufactured by Nikko Chemicals Co., Ltd. These phosphate ester compounds may be used individually or in combination.

[0054] On the other hand, the light-absorbing composition may not contain phosphate esters substantially. The presence of a silicon-containing compound α containing group α-1 in the light-absorbing composition allows 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 phosphate ester to the amount of silicon atoms in the silicon-containing compound α may be 3.0 or less on a molar basis, or the light-absorbing composition may not contain phosphate esters at all.

[0055] As described above, the light-absorbing composition does not need to contain curable resins other than the silicon-containing compound. On the other hand, the light-absorbing composition may contain a curable component such as a curable resin in addition to the silicon-containing compound α or β. Examples of curable components include curable resins, curable polymers, and monomers, dimers, or oligomers that are precursors of curable polymers. The curable component can be used to disperse or dissolve the light-absorbing compound in a desired state. The curable component is liquid in an uncured or unreacted state and can preferably disperse or dissolve the light-absorbing compound containing phosphonic acid and copper components. In addition, as the curable resin, preferably one that can form a coating film by applying the light-absorbing composition to a predetermined object by a coating method such as spin coating, spraying, dipping, and application with a dispenser is selected. As the curable resin, preferably one in which the transmission spectrum of a plate-like body formed by curing the resin is 90% or more at wavelengths of 450 nm to 800 nm with a smooth surface and a thickness of 1 mm is selected. Examples of curable resins include cyclic polyolefin resins, epoxy resins, polyimide resins, modified acrylic resins, silicone resins, and polyvinyl resins such as PVB, or their precursors. These curable resins may be used individually or in combination.

[0056] The light-absorbing composition may contain an ultraviolet absorber that absorbs some of the light belonging to the ultraviolet spectrum. The ultraviolet absorber is not limited to a specific compound. For example, an ultraviolet absorber is a compound that does not have both a hydroxyl group and a carbonyl group in a single molecule. For example, the curing of the light-absorbing composition may be promoted by the coordination of a reactant or precursor to a specific position within the molecule of the silicon-containing compound α. For example, if there is a group that is easily coordinated by a substance other than the substance used in the reaction for curing the light-absorbing composition, the catalytic effect may be weakened. In particular, both hydroxyl groups and carbonyl groups have high electron-donating properties, and it is conceivable that the silicon-containing compound α reacts with or coordinates with an ultraviolet absorber having these groups, and that some of them form a complex. In this case, the ultraviolet absorption properties inherent in the ultraviolet absorber may change. When the ultraviolet absorber is a compound that does not have both a hydroxyl group and a carbonyl group in a single molecule, the silicon-containing compound α is less likely to form a complex with the ultraviolet absorber, and the original ultraviolet absorption properties of the ultraviolet absorber are more likely to be exhibited. UV absorbers may contain either a hydroxyl group or a carbonyl group within a single molecule.

[0057] UV absorbers are preferably selected from the viewpoint of absorbing light in a desired wavelength range, being compatible with specific solvents, dispersing well in light-absorbing compositions, and having excellent environmental resistance. Examples of UV absorbers include benzophenone compounds, benzotriazole compounds, salicylic acid compounds, and triazine compounds. For example, Tinuvin PS, Tinuvin 99-2, Tinuvin 234, Tinuvin 326, Tinuvin 329, Tinuvin 900, Tinuvin 928, Tinuvin 405, and Tinuvin 460 can be used as UV absorbers. These are UV absorbers manufactured by BASF, and Tinuvin is a registered trademark.

[0058] The light-absorbing composition may contain water as needed. The light-absorbing composition may contain, for example, a predetermined amount of alkoxysilane. For example, silicon-containing compound α may be included in the light-absorbing composition as alkoxysilane. Hydrolysis may occur in the light-absorbing composition of alkoxysilane corresponding to silicon-containing compound α, or alkoxysilane not corresponding to silicon-containing compound α. Water may be included in the light-absorbing composition for this hydrolysis. Depending on the application, function, and storage environment of the light-absorbing composition, the light-absorbing composition may contain an appropriate amount of water.

[0059] On the other hand, in the process of solidifying a light-absorbing composition to produce a light absorber, a humidification treatment may be performed as a post-cure. In the humidification treatment, water components at the molecular level may be incorporated into the light absorber or its precursor, thereby promoting the hydrolysis of the alkoxysilane and the formation of siloxane bonds after hydrolysis. For example, when a process including humidification is employed, the light-absorbing composition does not need to contain substantially any water. In this case, the light-absorbing composition may contain water components that are pre-coordinated to compounds such as hydrates, or water components that are inevitably included without intentional addition.

[0060] The method for producing a light-absorbing composition is not limited to any particular method. For example, the method for producing a light-absorbing composition includes (I), (II), and (III) below. (I) Prepare a light-absorbing compound dispersion in which a light-absorbing compound containing phosphonic acid and copper components is dispersed in a solvent. (II) Mix a light-absorbing compound dispersion with an alkoxysilane containing a group having 10 or more carbon atoms, or a hydrolysate of the alkoxysilane. (III) Remove a portion of the solvent from the light-absorbing compound dispersion.

[0061] As shown in Figures 1A to 1D, a light absorber 10 can be provided. The light absorber 10 is provided, for example, as a solidified 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. As shown in Figure 1A, for example, the light absorber 10 alone can constitute an optical filter 1a. In this case, the optical filter 1a may be in the form of a film or a light-absorbing film. As shown in Figure 1B, the optical filter 1b may be composed of the light absorber 10 and the substrate 20.

[0062] In the light absorber 10, the average value T A 460-600 The percentage is over 80%. Average value T A 460-600 η is the average value of the transmittance in the wavelength range of 460 nm to 600 nm of the transmission spectrum obtained by incidenting light on the light absorber 10 at an incident angle of 0°. η is the value obtained by dividing the optical density OD of the light absorber 10 at wavelength λ by the thickness of the light absorber 10. λ [μm -1 It is expressed as ]. Optical density OD is OD = -log 10 It is expressed as [T(λ) / 100], where T(λ) is the transmittance at wavelength λ expressed as a percentage. In this case, for the light absorber 10, 0.009 ≤ η 380 and 0.008 ≤ η 750 The requirements are met. As a result, the light absorber 10 tends to have a transmittance close to the human visual sensitivity curve, even when thin. The light absorber 10 has high transmittance in the visible light range, and can effectively block light belonging to wavelengths other than visible light by absorption. In addition, the thin light absorber 10 can be used as an infrared cut filter or an ultraviolet cut filter. For this reason, optical filters placed near sensors or light-receiving surfaces can be made thinner, and the light absorber 10 can contribute to lowering the height of imaging devices and light-receiving devices such as ambient light sensors and illuminance sensors. The transmission spectrum of the light absorber 10 can be obtained, for example, by measuring the transmitted light with a spectrophotometer when light is incident on the light absorber 10 at an incident angle of 0°.

[0063] In the light absorber 10, the average value T A 460-600This is preferably 82% or higher, and more preferably 84% or higher. This results in a higher transmittance of the light absorber 10 in the visible light range, making it easier for the light absorber 10 to have a transmittance closer to the human visual sensitivity curve.

[0064] In the light absorber 10, preferably 0.012 ≤ η 380 The requirements are met. In the light absorber 10, preferably 0.010 ≤ η 750 The requirements are met. This allows light belonging to wavelengths other than visible light to be shielded more effectively, and the light absorber 10 is more likely to have a transmittance closer to the human visual sensitivity curve.

[0065] The light absorber 10 has a haze (cloudiness value) of less than 0.2%, for example. For example, the transmission spectrum and reflection spectrum of an optical filter incorporated into an imaging device are designed to satisfy predetermined conditions. On the other hand, even if an optical filter or light absorber has high transmittance in the visible light range, if the haze is large, some of the light incident on the optical filter or light absorber may be scattered or diffused inside it, resulting in cloudy or opaque optical properties. This can affect the formation of a sharp image. On the other hand, by having a haze of less than 0.2% in the light absorber 10, the transparency of the light absorber 10 is high, and for example, when the light absorber 10 is used in an imaging device, the imaging device is more likely to acquire high-quality images. The haze may be measured using the light absorber 10 alone, or it may be measured with the light absorber 10 placed on a glass or resin substrate.

[0066] The light absorber 10 preferably has a haze of 0.18% or less, and more preferably has a haze of 0.15% or less.

[0067] The light absorber 10 has a value of, for example, 0.018 ≤ η. 900 The requirement may be met, and 0.013≦η 1100 The requirements may also be met. The light absorber 10 has a coefficient of 0.016 ≤ η 800 The requirement may be met, and 0.013≦η 1000It may also satisfy the requirements. This makes it easier for the light absorber 10 to have a transmittance closer to the human visual sensitivity curve, even if it is thin.

[0068] The light absorber 10 preferably has a value of 0.020 ≤ η 900 The requirement may be met, and 0.015≦η 1100 The requirement may be met, and 0.018≦η 800 The requirement may be met, and 0.018≦η 1000 It may also satisfy the requirements.

[0069] The light absorber 10 is, for example, T A 300-380 ≤1.5% and T A 750-1100 The requirement of ≤2.0% is met. A 300-380 This is the average value of the transmittance in the wavelength range of 300 nm to 380 nm of the transmission spectrum obtained by incidenting light on the light absorber 10 at an incident angle of 0°. A 750-1100 This is the average value of the transmittance within the wavelength range of 750 nm to 1100 nm of its transmission spectrum. In this case, the light absorber 10 is more likely to have a transmittance that is closer to the human visual sensitivity curve.

[0070] The light absorber 10 is preferably T A 300-380 The requirement of ≤1.2% is met, and more preferably T A 300-380 The requirement of ≤1.0% is met. The light absorber 10 is preferably T A 750-1100 The requirement of ≤1.5% is met, and more preferably T A 750-1100 The requirement of ≤1.0% is met.

[0071] In the light absorber 10, for example, 390 nm ≤ λ 0 UV The requirement of ≤450nm is met, and 600nm ≤λ 0 IR The requirement of ≤680nm may be met. λ 0 UVis the first ultraviolet cut-off wavelength with a transmittance of 50% within the wavelength range of 350 nm to 460 nm. λ 0 IR is the first infrared cut-off wavelength with a transmittance of 50% within the wavelength range of 600 nm to 700 nm. In the light absorber 10, preferably, the requirement of 393 nm ≤ λ 0 UV ≤ 450 nm is satisfied, and more preferably, the requirement of 395 nm ≤ λ 0 UV ≤ 450 nm is satisfied. In the light absorber 10, preferably, the requirement of 605 nm ≤ λ 0 IR ≤ 680 nm is satisfied, and more preferably, the requirement of 610 nm ≤ λ 0 IR ≤ 680 nm is satisfied.

[0072] The light absorber 10 satisfies, for example, the requirement of R A 450-550 ≤ 10%, and satisfies the requirement of R A 700-1000 ≤ 8%. R A 450-550 is the average value of the reflectance in the wavelength range of 450 nm to 550 nm. R A 700-1000 is the average value of the reflectance in the wavelength range of 700 nm to 1000 nm. The reflectance is determined, for example, based on the reflection spectrum obtained by irradiating the light absorber 10 with light of 300 nm to 1200 nm at an incident angle of 5°. When the light absorber 10 absorbs a part of the light of a specific wavelength so as to satisfy these requirements, for example, in an imaging device in which the light absorber 10 is incorporated, it is possible to suppress the occurrence of light reflection or scattering in the interior of the housing of the imaging device or the aperture, resulting in a decrease in the contrast of the captured image such as ghost or flare.

[0073] The light absorber 10 preferably satisfies the requirement of R A 450-550 ≤ 8%. The light absorber 10 preferably satisfies the requirement of R A 700-1000 ≤ 6%.

[0074] The light absorber 10 is, for example, R 380 <R 350 It satisfies the requirements of R. 380 This is the reflectance at a wavelength of 380 nm, and R 350 This is the reflectance at a wavelength of 350 nm. In this case, the occurrence of ghosting or flare, which leads to a decrease in image contrast, is more easily suppressed.

[0075] The above transmittance, η λ The requirements for haze and reflectance may be met in the optical filter equipped with the light absorber 10.

[0076] Thickness d of the light absorber 10 L It is not limited to a specific value. Thickness d L For example, the particle size is 150 μm or less, preferably 120 μm or less, and more preferably 110 μm or less.

[0077] As shown in Figure 1A, when the light absorber 10 constitutes the optical filter 1a by itself, the thickness of the optical filter 1a tends to be small, and the optical filter 1a may be in the form of a film. Therefore, the optical filter 1a tends to contribute significantly to lowering the height of the device into which it is incorporated. On the other hand, as shown in Figure 1B, an optical filter 1b comprising the light absorber 10 and a substrate 20 may be provided. In this case, the rigidity or mechanical strength of the optical filter 1b tends to be high, and the optical filter 1b may be provided as a rigid optical filter.

[0078] The substrate 20 may have its surface formed by, for example, glass, resin, or metal. The type of substrate 20 and its optical properties are such that the light absorber 10 or the optical filter equipped with the light absorber 10 has a desired transmittance, η λAs long as it has haze and reflectivity, it is not limited to any particular embodiment. In addition, the shape of the substrate 20 is not limited to any particular shape. As shown in Figure 1B, the substrate 20 is, for example, a flat plate. In this case, the application of the light-absorbing composition is easy, and the versatility of the optical filter 1b tends to be high. On the other hand, the substrate 20 may include curved surfaces, convex surfaces, or concave surfaces. The substrate 20 may have a shape other than a plate. The substrate 20 may be an optical element, and examples of optical elements are lenses, polarizers, prisms, reflectors, and diffraction gratings. These optical elements may include curved surfaces and planar surfaces. Another example of the substrate 20 is a photoelectric conversion element such as a photodiode and a phototransistor, an image sensor in which a number of photoelectric conversion elements such as a CCD or CMOS are arranged, and an image sensor equivalent to this image sensor. In some cases, the light absorber 10 may be placed directly on a light-receiving surface or window glass. Yet another example of the substrate 20 is a display device such as a display in a portable terminal.

[0079] 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 optical filter 1b. For example, if the substrate 20 is transparent, the transmission spectrum of a 3 mm thick parallel plate made of the same material as the substrate 20 may have a transmittance of 90% or more in the wavelength range of 360 nm to 900 nm and a transmittance of 85% or more in the wavelength range of 350 nm to 1200 nm. A typical example of a substrate 20 material having such transmission characteristics 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 shows the transmission spectrum of a 3 mm thick D263T eco plate. In this 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 may be phosphate glass or fluorine phosphate glass containing coloring components such as Cu and Co. The glass containing coloring components is, for example, infrared absorbing glass, in which case the substrate 20 itself has light-absorbing properties. When the substrate 20 is a substrate containing infrared absorbing glass, the optical filter 1b is more likely to have the desired optical properties by adjusting the light absorption and transmission spectra of both the light absorber 10 and the substrate 20. In addition, the design flexibility of the optical filter 1b is likely to be increased.

[0080] The base material 20 may contain a resin. Examples of resins included in the base material 20 are 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 base material 20 contains a resin, it is easy to obtain base materials 20 in various shapes, such as optical elements.

[0081] As shown in Figure 1C, the optical filter 1c comprises a light absorber 10 and a light-absorbing substrate 21. The light-absorbing substrate 21 is a substrate that has the function of absorbing a portion of light of a specific wavelength, and on which the light absorber 10 can be placed. The light-absorbing substrate 21 may contain glass containing the above-mentioned coloring component, or it may be a resin substrate containing dyes, pigments, and colorants.

[0082] An optical filter equipped with a light absorber 10 may also be provided with an anti-reflective coating or a light reflection reduction coating to prevent or reduce reflection of light incident on the optical filter. In this case, the anti-reflective coating or light reflection reduction coating (hereinafter collectively referred to as "anti-reflective coating") forms the surface of the optical filter. As shown in Figure 1D, the optical filter 1d includes a light absorber 10 and anti-reflective coatings 31a and 31b provided on the surface of the light absorber 10. The anti-reflective coatings 31a and 31b are arranged along the surface of the light absorber 10. For example, if the optical filter comprises a transparent substrate and a light absorber 10 disposed on the transparent substrate, the anti-reflective coating may be provided 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 light absorbers provided with anti-reflective coatings and optical filters equipped with such light absorbers and anti-reflective coatings are also included within the scope of the present invention.

[0083] The anti-reflective coating can increase the transmittance of the light absorber 10 or the optical filter equipped with the light absorber 10 in the wavelength band through which light passes (transmission wavelength band). The transmission wavelength band is, for example, the wavelength band in which the transmittance is 50% or more in the transmission spectrum at an incident angle of 0° of the light absorber or optical filter.

[0084] When an anti-reflective coating is formed on the light absorber 10, the optical filter, or a transparent substrate for supporting them (for example, D263T eco manufactured by SCHOOT), the reflectance in the reflection spectrum obtained by incident light with wavelengths of 300 nm to 1200 nm at an incident angle of 5° is, for example, 1% or less in the wavelength range of 400 nm to 600 nm. This reflectance is preferably 0.5% or less, and more preferably 0.25% or less.

[0085] In this reflection spectrum, the average reflectance in 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 the image obtained due to the reflection of some of the light belonging to the infrared spectrum. This average reflectance is preferably 0.5% or less, and more preferably 0.25% or less.

[0086] When an anti-reflective coating is formed on the light absorber 10, etc., in the reflection spectrum obtained by incidenting light with wavelengths of 300 nm to 1200 nm at an incident angle of 50°, the reflectance at wavelengths of 400 nm to 600 nm is, for example, 3% or less. In this case, even when the incident angle to the light absorber 10 or the optical filter equipped with the light absorber 10 is large, the reflectance of the light absorber 10 or the optical filter equipped with the light absorber 10 is low. This reflectance is preferably 1% or less. In this reflection spectrum, the reflectance at wavelengths of 700 nm to 1200 nm is, for example, 3% or less. In this case, even when the incident angle to the light absorber 10 or the optical filter equipped with the light absorber 10 is large, the reflectance of the light absorber 10 or the optical filter equipped with the light absorber 10 is low. This reflectance is preferably 1.5% or less.

[0087] The anti-reflective coating is not limited to a specific type of coating. The anti-reflective coating includes at least one layer selected from the group consisting of (a), (b), and (c) below. The anti-reflective coating may include two or more layers selected from this group. In Figure 1D, each of the anti-reflective coatings 31a and 32a is shown as a single layer example, but this figure is functionally depicted to distinguish each anti-reflective coating from the light absorber 10. In practice, the anti-reflective coatings 31a and 32a may be monolayers composed of substantially the same material, or they may be multilayers composed of multiple layers of different materials. (a) Layer formed by the sol-gel method using a silicon-containing reactive material. (b) A layer formed by a sol-gel method using a silicon-containing reactive material, further comprising fine particles. (c) Layers formed by physical film deposition methods such as vacuum deposition and sputtering.

[0088] Regarding the layer described in (a) above, the silicon-containing reactive material is not limited to a specific material. Preferably, the reactive material includes trifunctional silanes such as methyltriethoxysilane (MTES) and tetrafunctional silanes such as tetraethoxysilane (TEOS). Tetrafunctional silanes are important for forming a layer with a strong and dense framework. On the other hand, with tetrafunctional silanes alone, it is difficult to control the reactivity and polarity selectivity is poor. In addition, cracks are likely to occur. By adding trifunctional silanes, the flexibility of the silica framework is improved, polarity controllability is enhanced, and cracks are less likely to occur. As a result, the refractive index required for the anti-reflective film can be adjusted by adjusting the polarity. The organic functional group contained in the trifunctional silane is not limited to a specific functional group. For example, the organic functional group is a methyl group. In this case, when trifunctional silanes are combined with tetrafunctional silanes, homogeneous liquids and coatings can be easily formed. The ratio of the amount of trifunctional silane to the amount of tetrafunctional silane is not limited to a specific value. The ratio is, for example, 1 / 3 to 5 on a molar basis. This allows for the suppression of crack formation in the anti-reflective coating by the trifunctional silane, while enabling the formation of a robust framework by the tetrafunctional silane. The silicon-containing reactive material may further contain a difunctional silane.

[0089] Trifunctional silanes are not limited to specific silanes. Examples of trifunctional silanes include methyltriethoxysilane, methyltrimethoxysilane, ethyltriethoxysilane, ethyltrimethoxysilane, propyltriethoxysilane, propyltrimethoxysilane, butyltriethoxysilane, butyltrimethoxysilane, pentyltrimethoxysilane, pentyltriethoxysilane, hexyltriethoxysilane, and hexyltrimethoxysilane, and may be trifunctional silanes having an alkyl group directly bonded to a silicon atom (Si). Tetrafunctional silanes are not limited to specific silanes. Examples of tetrafunctional silanes include tetraethoxysilane, tetramethoxysilane, tetrapropoxysilane, and tetrabutoxysilane.

[0090] Silane compounds contained in silicon-containing reactive materials also undergo hydrolysis to become hydrolyzed products of silane compounds containing silanol groups. Furthermore, through condensation polymerization of these hydrolyzed products, trifunctional silanes can become (poly)silsesquioxanes, and tetrafunctional silanes can change to a silica structure.

[0091] Since the refractive indices of (poly)silsesquioxane and silica are low, around 1.46, layers with low refractive indices are easily formed. A layer containing at least one selected from the group consisting of (poly)silsesquioxane and silica is suitable as a layer included in the anti-reflective coating of the light absorber 10 or an optical filter equipped with the light absorber 10.

[0092] The firing of the reactive material coating can be carried out, for example, in the range of 60°C to 170°C. The firing temperature is preferably 60°C to 150°C, and more preferably 60°C to 115°C.

[0093] With respect to the layer described in (b) above, the layer containing the silicon-containing reactive material, the hydrolysate of this reactive material, or the condensed polymer of this hydrolysate contains particles. The particles include, for example, at least one selected from the group consisting of silica, titania, zirconia, alumina, and magnesium fluoride. The refractive index of the material forming the particles is, for example, 1.30 to 2.55. The particles preferably contain silica. In layers containing silica or (poly)silsesquioxane, they act as binders surrounding the particles. As a result, the bonding strength between the particles and the binder is improved via silanol groups, etc., which tends to increase the weather resistance of the anti-reflective coating and is expected to improve the reliability of the anti-reflective coating.

[0094] The particles in layer (b) may be hollow particles. The layer containing hollow particles, silsesquioxane, and silica is distinguished from the layer containing solid particles described later as layer (b1). Because hollow particles contain empty space inside, their refractive index tends to be very low. The refractive index of hollow particles is, for example, 1.02 to 1.50. The average particle diameter of hollow particles is, for example, 5 nm to 200 nm. The average particle diameter of fine particles is, for example, the particle diameter at which the cumulative sum from the smallest particles reaches 50% in the number-based particle size distribution curve measured according to the laser diffraction-scattering method using a laser diffraction-scattering particle size analyzer (median diameter). As a laser diffraction-scattering particle size analyzer, for example, the "LA-960V2 series" laser diffraction / scattering particle size distribution analyzer manufactured by Horiba, Ltd. can be used. Furthermore, the average particle size of the fine particles may be determined by observing a cross-section of the structure containing layer (b1) at 100,000x magnification using a scanning electron microscope (SEM), measuring the particle size of the fine particles contained within the field of view or a predetermined range (for example, within a 500 nm square area), and then calculating the average value. This method may be particularly useful when determining the diameter of fine particles contained in a solidified or solid layer. The fine particle content in layer (b1) is, for example, 5% to 95% by mass. Furthermore, the content of fine particles in layer (b1) is, for example, 30% to 99% by volume. The content of fine particles in layer (b1) is determined by observing the cross-section of the structure containing layer (b1) under 100,000x magnification using SEM, and then calculating the ratio of the volume of fine particles to the volume of layer (b1). Generally, the larger the proportion of hollow particles in layer (b1), the lower the refractive index of the layer tends to be. The content of fine particles in layer (b1) may also be, for example, 75% to 99% by volume.

[0095] In a layer containing such hollow particles and at least one selected from the group consisting of silica and (poly)silsesquioxane, the refractive index of the layer tends to be very low. For example, the refractive index of layer (b1) is, for example, 1.00 to 1.45. The hollow particles may be hollow silica particles, for example, JGC Catalysts & Chemicals' Thru-Ria 4110 or 1110 can be used. The refractive index of layer (b1) may be determined as follows: A laminate is prepared including a substrate with a known refractive index within a specific wavelength range and a layer of (b1) provided on the surface of the substrate, and the reflection spectrum of the laminate is measured. Furthermore, the thickness of layer (b1) is determined by obtaining it from a magnified cross-sectional image using an SEM, or by measurement using a laser measuring microscope, etc. Using the refractive index of layer (b1) as a variable, the refractive index that best matches the measured reflection spectrum is determined.

[0096] In a layer containing 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 layer tends to be lower in the former case. For this reason, a high anti-reflective effect can be expected in a structure in which an anti-reflective coating is laminated in the following order: a layer containing hollow particles and at least one selected from the group consisting of silica and (poly)silsesquioxane, a layer containing hollow particles and at least one selected from the group consisting of silica and (poly)silsesquioxane, and an optical filter or light absorber 10.

[0097] The fine particles contained in layer (b) may be solid particles. The layer containing solid particles, silsesquioxane, and silica is distinguished from the layer containing hollow particles as described above as layer (b2). The refractive index of the solid particles is, for example, 1.25 to 2.75. If layer (b) contains solid particles, the refractive index of layer (b2) is, for example, 1.40 to 2.50. The average particle diameter 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 Corporation can be used. The refractive index of layer (b2) may be determined by the same method as the refractive index of layer (b1) described above.

[0098] The layer (b2) may contain particles having a relatively high refractive index, or may be formed as a layer having a relatively high refractive index. For example, the layer (b2) may contain one selected from the group consisting of TiO2 (titanium oxide, refractive index 2.33~2.55), Ta2O5 (tantalum oxide, refractive index 2.16), Nb2O5 (niobium oxide, refractive index 2.33), and Si3N4 (silicon nitride, refractive index 2.02), or at least two selected from this group may be mixed and contained. In particular, the layer (b2) may contain TiO2 particles. In this case, the average particle size of the TiO2 particles may be 2 nm to 200 nm. The TiO2 particle content in the layer (b2) is, for example, 2% to 50%. As TiO2 particles, for example, NS405 from Teika Corporation and TTO-51A from Ishihara Sangyo Co., Ltd. can be used. Furthermore, the average particle size of the fine particles contained in layer (b2) may be determined by the same method as the average particle size of the fine particles contained in layer (b1). The fine particle content in layer (b2) is, for example, 5% by mass to 95% by mass. The fine particle content in layer (b2) is, for example, 30% by volume to 99% by volume. The fine particle content in layer (b2) may be determined by the same method as determining the volume percentage of fine particles contained in layer (b1).

[0099] These particles may be surface-treated with a silane coupling agent or a titanium coupling agent, etc., to improve adhesion or wettability with the binder or matrix. This surface treatment may also be effective for particles other than TiO2 and SiO2 particles.

[0100] Layers (a), (b1), and (b2) contain silicon compounds as a binder or matrix, similar to light absorbers containing silicon compounds. Therefore, alkoxy groups and their hydrolyzed silanol groups are present between the layers and react with hydroxyl groups, etc., which can be expected to improve adhesion and contribute to improved peel resistance. Furthermore, layers (a), (b1), and (b2) are classified, for example, into low refractive index layers, medium refractive index layers, and high refractive index layers. In this case, the low refractive index layer is the (b1) layer containing at least one selected from the group consisting of silica and (poly)silsesquioxane and containing hollow particles. The medium refractive index layer is the (a) layer containing at least one selected from the group consisting of silica and (poly)silsesquioxane and not containing hollow particles. The high refractive index layer is the (b2) layer containing at least one selected from the group consisting of silica and (poly)silsesquioxane and further containing particles with a relatively high refractive index, such as TiO2 particles. For example, an anti-reflective coating may be constructed considering the combination of these layers, the thickness of the layers, the number of layers, the repeating pattern in the combination of layers, etc. A comparison of the refractive indices of each layer satisfies the condition that the refractive index of layer (b1) < the refractive index of layer (a) < the refractive index of layer (b2).

[0101] The anti-reflective coating may be constructed by laminating a layer (b1) containing silica, (poly)silsesquioxane, and hollow particles, and a layer (b2) containing silica, (poly)silsesquioxane, and solid particles having a relatively high refractive index, such as TiO2 particles. The refractive index of layer (b2) is higher than that of layer (b1). Constructing the anti-reflective coating by laminating layers with substantially different refractive indices in this way is highly effective in terms of expanding the anti-reflective band and reducing reflectivity.

[0102] Layers (a), (b1), and (b2) can be prepared by known methods. Specifically, a trifunctional alkoxysilane, which is the material for silsesquioxane, a tetrafunctional silane, which is the material for silica, an acid or alkaline catalyst, and water for hydrolysis are mixed and hydrolyzed in an organic solvent that is soluble in alkoxysilane and water to obtain sol-like precursors of layers (a), (b1), and (b2), etc. In particular, hollow particles or solid particles are added to the precursors of layers (b1) and (b2), etc., as needed. The hollow particles or solid particles may be pre-treated with silane by reacting them with a silane coupling agent or the like. This can improve adhesion and wettability with the binder (a compound containing silsesquioxane and silica that binds to the particles).

[0103] The sol precursor prepared in this manner is coated onto a substrate requiring an anti-reflective effect, in this case a light absorber or optical filter, by adjusting the coating conditions and application amount to achieve a predetermined thickness. Examples of coating methods include spin coating, dip coating, roll coating, dispensing coating, spray coating, and bar coating, and other coating methods may also be used. After coating the sol precursor, reactions such as hydrolysis of the alkoxysilane and polymerization of the hydrolysate proceed, causing the sol precursor to solidify. Heating may also be preferably performed to promote the reaction or remove by-products. In addition to the reaction in the sol, a solidification process may be included in which a gel is produced by evaporation or drying of the solvent or liquid component.

[0104] Regarding the layer described in (c) above, the layer described in (c) can be formed as a dielectric or metal oxide layer by physical deposition methods such as vacuum deposition including ion-assisted deposition (IAD), sputtering, and ion plating. The material forming the layer described in (c) is not limited to a specific material. Examples of materials that make up the layer described in (c) include SiO2, TiO2, Ta2O3, SnO2, In2O3, Nb2O5, Si3N4, and TiN xThe material comprises at least one material selected from the group consisting of , and MgF2. Layer (c) may be composed of a material in which these compounds are mixed in a predetermined ratio, and the refractive index of the layer contained in layer (c) may be adjusted by adjusting the mixing ratio of the material in which different compounds are mixed.

[0105] The layer in (c) may be a single layer made of the same material, or it may be a multilayer made of two or more layers containing different types of materials selected from the above compound and mixtures of the above compound. If the layer in (c) is a multilayer, for example, an anti-reflective film may be formed by alternately laminating layers made of materials with relatively high refractive indices such as TiO2, Ta2O3, and Nb2O5 or mixtures thereof, and layers made of materials with relatively low refractive indices such as SiO2 and MgF2 or mixtures thereof, while adjusting the thickness and number of repetitions of these layers. In this case as well, laminating layers with substantially different refractive indices to form an anti-reflective film is expected to be highly effective in terms of expanding the anti-reflective band or reducing reflectivity, and is advantageous for users of optical filters or light absorbers.

[0106] In an optical filter 1d in which anti-reflective coatings 31a and 32a are provided on both sides of a light absorber 10, the average value T2 of the transmittance at wavelengths of 400 nm to 600 nm A 460-600 The attenuation rate is preferably 90% or higher, and more preferably 94% or higher. In this case, in the visible light region, light passes through the optical filter 1d with almost no attenuation. Therefore, the optical filter 1d has extremely advantageous properties as an optical filter used in an imaging device.

[0107] Furthermore, in an optical filter 1d in which anti-reflective coatings 31a and 32a are provided on both sides of the light absorber 10, the value obtained by dividing the OD value, which is the optical density at wavelength λ, by the thickness of the light absorber (the thickness of the optical filter minus the thickness of the anti-reflective coating) is η 2-λ [μm -1 When ], 0.009≦η 2-380 and 0.008≦η 2-750 It is desirable that 0.012 ≤ η2-380 and 0.010≦η 2-750 It would be even more desirable if that were the case.

[0108] In an optical filter 1d in which anti-reflective coatings 31a and 32a are provided on both sides of the light absorber 10, it is desirable that the haze (cloudiness) be less than 0.2%, more preferably 0.18% or less, and particularly desirable 0.15% or less, similar to an optical filter without an anti-reflective coating.

[0109] In an optical filter 1d in which anti-reflective coatings 31a and 32a are provided on both sides of a light absorber 10, for example, 0.020 ≤ η 2-900 The requirement may be met, and 0.013≦η 2-1100 The requirements may also be met. Furthermore, the optical filter 1d has a ratio of 0.020 ≤ η 2-800 The requirement may be met, and 0.012≦η 2-1000 It may also satisfy the following conditions.

[0110] The optical filter 1d preferably has a value of 0.022 ≤ η 2-900 The requirement may be met, and 0.015≦η 2-1100 The requirement may be met, and 0.025≦η 2-800 The requirement may be met, and 0.015≦η 2-1000 It may also satisfy the following conditions.

[0111] An optical filter 1d having anti-reflective coatings 31a and 32a on both sides of a light absorber 10 is, for example, T2 A 300-380 ≤1.5% and T2 A 750-1100 The requirement of ≤2.0% may be met, and preferably T2 A 300-380 ≤1.2% and T2 A 750-1100 The requirement of ≤1.5% may be met, and more preferably, T2 A 300-380 ≤1.0% and T2 A 750-1100 The requirement of ≤1.0% may be met. T2 A300-380 This is the average transmittance at wavelengths of 300nm to 380nm, and T2 A 750-1100 This represents the average transmittance in the wavelength range of 750 nm to 1100 nm.

[0112] An optical filter 1d, in which anti-reflective coatings 31a and 32a are provided on both sides of a light absorber 10, for example, has a wavelength of 390 nm ≤ λ². 0 UV The requirements are ≤450nm and ≤λ² for 600nm. 0 IR It meets the requirement of ≤680nm. λ2 0 UV This is the second ultraviolet cutoff wavelength in optical filter 1d where the transmittance is 50% in the wavelength range of 350nm to 460nm, and λ2 0 IR This is the second infrared cutoff wavelength at which the transmittance is 50% in the optical filter 1d within the wavelength range of 600nm to 700nm.

[0113] An ambient light sensor comprising a light absorber 10 or an optical filter containing a light absorber 10 may be provided. An ambient light sensor is a device mounted on equipment that detects the brightness or hue of the surrounding area. The ambient light sensor recognizes the light attributes around the equipment, and for example, the brightness of a display device such as a display mounted on the equipment is automatically adjusted. Ambient light sensors are sometimes also called luminance sensors or illuminance sensors.

[0114] Figure 3A is a cross-sectional view showing an example of an ambient light sensor. As shown in Figure 3A, the ambient light sensor 2a comprises, for example, an electrical circuit board 3, a photoelectric conversion element 4, a housing 5, and an optical filter 1a. The ambient light sensor 2a detects, for example, the attributes of light belonging to the visible light range among the attributes of light around a device equipped with the ambient light sensor 2a. The electrical circuit board 3 supports the ambient light sensor 2a and electrically connects the ambient light sensor 2a to surrounding devices. The photoelectric conversion element 4 is arranged on the electrical circuit board 3 and includes, for example, an element such as a photodiode or phototransistor. The housing 5 is arranged on the electrical circuit board 3 and surrounds the photoelectric conversion element 4. The optical filter 1a is, for example, arranged in front of the photoelectric conversion element 4 and shields a portion of the light traveling toward the photoelectric conversion element 4. The optical filter 1a shields, for example, a portion of the light belonging to the ultraviolet or infrared range. The optical filter 1a is supported by the housing 5.

[0115] The ambient light sensor may include an optical filter equipped with a light absorber 10, as shown in Figure 3A, or it may include an integrated photoelectric conversion element in which the light absorber 10 and the photoelectric conversion element are integrated, as shown in Figure 3B. The photoelectric conversion element 2b shown in Figure 3B includes 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 this order. The photoelectric conversion element 2b is an integrated photoelectric conversion element. An integrated photoelectric conversion element can be obtained, for example, by applying the above-mentioned light-absorbing composition to the surface of the light-receiving surface (window) of the photoelectric conversion element and curing it to form the light absorber 10. When using such a photoelectric conversion element, it is not necessary to use a light absorber separately from the photoelectric conversion element. Such an ambient light sensor can block some light outside the visible light range, such as ultraviolet or infrared light, through absorption by the light absorber 10. This significantly improves the ease of use of the ambient light sensor, as it is specialized for detecting light in the nearly visible light range. In addition, it can be expected to simplify the supply chain for product distribution.

[0116] In the photoelectric conversion element 2b, for example, the first electrode E1 and the photoelectric conversion layer L are stacked on the electrical circuit board 3 in this order. In addition, the second electrode E2, the light-receiving surface 2f, and the light-absorbing body 10 are arranged on the photoelectric conversion layer L.

[0117] The surface of the light absorber 10 or the optical filter containing the light absorber 10, which is mounted on the ambient light sensor, may be provided with an anti-reflective coating or a reflection-reducing coating in order to reduce reflectivity and increase transmittance of light of a predetermined wavelength.

[0118] An imaging device or camera module equipped with a light absorber 10 or an optical filter including the light absorber 10 may be provided. The imaging device or camera module includes, for example, an image sensor, an electrical circuit board, a lens system, and an optical filter equipped with the light absorber 10. In the image sensor, for example, a number of photoelectric conversion elements such as a CCD or CMOS are arranged. The electrical circuit board electrically connects the image sensor to an external device. The lens system includes one or more lens groups for focusing light from a subject or the like onto the image sensor to form an image. The light absorber 10 or the optical filter equipped with the light absorber 10 can block some light belonging to the ultraviolet and infrared regions.

[0119] For example, in an imaging device equipped with a light absorber 10 or an optical filter equipped with a light absorber 10, some light belonging to the ultraviolet and infrared regions is blocked by absorption, and light belonging to the visible light range is transmitted through the optical filter toward the image sensor. If the optical filter has the function of reflecting some light by a dielectric multilayer film or the like, some of the light reflected by the optical filter is reflected inside the housing or on the surface of a lens system placed in front of the optical filter, or some of these reflected lights project the aperture or its shape and reach the light-receiving surface of the image sensor, causing phenomena that degrade contrast, such as ghosting and flare, to become apparent. On the other hand, with an imaging device equipped with an optical filter equipped with a light absorber 10, such phenomena are less likely to occur, and ghosting or flare is less noticeable in the acquired image.

[0120] Figure 4A shows an example of an imaging device. This figure provides a schematic representation of the imaging device, and only the elements necessary for explanation are schematically shown, with other parts or elements omitted. As shown in Figure 4A, the imaging device 6a comprises an image sensor 7, a lens system 8, and an optical filter 1a. In the imaging device 6a, the optical filter 1a is positioned, for example, between the image sensor 7 and the lens system 8, directly in front of the image sensor 7. The arrangement of the optical filter is not limited to the arrangement shown in Figure 4A. The optical filter may be positioned on the subject side, in front of the lens system 8. In this case, the optical filter comprises, 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 optical filter can be expected to function as a protective filter to protect the imaging device and lens system from external elements.

[0121] Figure 4B shows another example of an imaging device. The imaging device 6b is configured similarly to the imaging device 6a, except for parts that are not specifically described. As shown in Figure 4B, in the imaging device 6b, a light absorber 10 is placed on the surface of some of the lenses 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 placed so as to form an interface with the lens 8a. This allows the lens system 8 to have the desired light shielding properties without the need to provide a separate light-absorbing optical filter from the lens system 8, thus significantly simplifying the assembly or manufacture of the imaging device. A lens 8a with such a light absorber 10 integrally formed, or a lens system including such a lens 8a, may be supplied. An anti-reflective film or a reflection-reducing film may be formed on the surface of the light absorber 10. This reduces reflected light from the surface of the light absorber 10 and tends to increase transmitted light in the visible light range. In the imaging device 6b, the arrangement of the light absorber 10 is not limited to the arrangement shown in Figure 4B.

[0122] The lens system of an imaging device may include a group of lenses formed by bonding the surfaces of two or more lenses together. An adhesive or a curable resin may be used to bond the lenses together. Although not shown in the diagram, the above-mentioned light-absorbing composition may be used as an adhesive or the like for bonding the lenses together. In this case, the light absorber 10 is less susceptible to the external environment of the lens system, and protection of the light absorber 10 or the components contained in the light absorber 10 is expected. If the light-absorbing composition is prepared so that the refractive indices of the light absorber 10 and the lens are approximately the same, the reflection at the interface between the light absorber 10 and the lens can be significantly reduced, and the advantage of not needing an anti-reflective coating is obtained. [Examples]

[0123] The present invention will be described in more detail by reference to examples. However, the present invention is not limited to the following examples.

[0124] <Example 1> 4.500 g of copper acetate monohydrate and 240 g of tetrahydrofuran (THF) were mixed and stirred for 3 hours to obtain solution (1-A), which is a copper acetate solution. Next, 0.610 g of phenylphosphonic acid was added to 40 g of THF and stirred for 30 minutes to obtain solution (1-B). 3.660 g of 4-bromophenylphosphonic acid was added to 40 g of THF and stirred for 30 minutes to obtain solution (1-C). 0.758 g of n-butylphosphonic acid was added to 40 g of THF and stirred for 30 minutes to obtain solution (1-D). Solution (1-A) was mixed with solutions (1-B), (1-C), and (1-D), and then 4.00 g of the trifunctional alkoxysilane n-hexadecyltrimethoxysilane and 2.78 g of the tetrafunctional alkoxysilane tetraethoxysilane were added, and the mixture was stirred for a further 1 minute to obtain solution (1-E). Next, 40 g of toluene was added to solution (1-E), and the mixture was stirred at room temperature for 1 minute to obtain solution (1-F). This solution (1-F) was placed in a flask and treated with a rotary evaporator (Tokyo Rikakikai Co., Ltd., model: N-1110SF) while being heated in an oil bath (Tokyo Rikakikai Co., Ltd., model: OSB-2100) to advance the reaction and remove THF. The oil bath temperature was set to 85°C. After that, the treated liquid was removed from the flask. In this way, a light-absorbing composition (1-G), which is a liquid light-absorbing composition according to Example 1, was obtained, containing a light-absorbing compound containing phosphonic acid and copper components, and a silicon-containing compound containing an n-hexadecyl group. Table 1 shows the amount (content) of each compound added in the preparation of the light-absorbing composition according to Example 1. Table 1 also shows the amount (content) of each compound added in the preparation of the light-absorbing compositions according to other examples and each comparative example.

[0125] A coating of the light-absorbing composition (1-G) was formed on one main surface of a borosilicate glass substrate (manufactured by SCHOTT, product name: D263 T eco) having dimensions of 76 mm × 76 mm × 0.21 mm using a dispenser. After the obtained coating was thoroughly dried at room temperature, it was placed in an oven and heated at a temperature of room temperature to 85°C for about 6 hours to allow the reaction of the alkoxysilane to proceed sufficiently and to volatilize the organic solvent contained in the light-absorbing composition (1-G). Subsequently, the coating was further cured by leaving it in an environment of 85°C and 85% relative humidity for another 8 hours to complete the reaction. In this way, the light absorber according to Example 1 was obtained. In addition, an optical filter according to Example 1 was obtained in which the light absorber according to Example 1 was placed on a substrate.

[0126] The haze of the light absorber in Example 1 was measured using a HM-65L2 haze meter manufactured by Murakami Color Technology Laboratory Co., Ltd., in accordance with the Japanese Industrial Standard JIS K 7136:2000. As shown in Table 2, the haze value of the light absorber in Example 1 was 0.19%. Table 2 also shows the haze values ​​of the light absorbers in other examples and comparative examples, except where measurement was not performed.

[0127] The thickness of the light absorber according to 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 according to Example 1 was 97 μm. Table 2 also shows the thicknesses of the light absorbers according to other examples and comparative examples, except where measurements were not taken.

[0128] The transmission spectrum of the light absorber according to Example 1 at an incident angle of 0° was measured using a UV-Vis-Near Infrared Spectrophotometer V-770 equipped with a transmitted light measurement attachment manufactured by JASCO Corporation. Unless otherwise specified, the transmission spectrum was measured with the ambient temperature around the optical filter adjusted to 22-25°C. In this measurement, the measurement attachment was replaced with a reflected light measurement attachment to measure the reflected spectrum of the light absorber according to Example 1 at an incident angle of 5°. Unless otherwise specified, the reflected spectrum was measured with the ambient temperature around the optical filter at 22-25°C. Figure 5A shows the transmission spectrum of the light absorber according to Example 1. Figure 5B shows the reflected spectrum of the light absorber according to Example 1. Table 2 shows the characteristic values ​​of the optical conditions of the light absorber at an incident angle of 0°. Table 3 shows η, which is obtained by dividing the optical density at a specific wavelength by the thickness of the light absorber. λ The values ​​of are shown. Tables 2 and 3 show the characteristic values ​​of the transmittance or reflectance of the light absorber for other examples and each comparative example, and η λ This shows the value.

[0129] <Examples 2-14> Light absorbers for Examples 2 to 12 were prepared using the same method and conditions as in Example 1, except that the required compounds and their amounts were changed as shown in Table 1A. Light absorbers for Examples 13 and 14 were also prepared using the same method and conditions as in Example 1, except that the required compounds and their amounts 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 and reflectance spectra of the light absorber for Example 2 are shown in Figures 6A and 6B, respectively. The transmission and reflectance spectra of the light absorber for Example 3 are shown in Figures 7A and 7B, respectively. The transmission spectrum of the light absorber for Example 8 is shown in Figure 8. The transmission spectrum of the light absorber for Example 13 is shown in Figure 9. The transmission spectrum of the light absorber for Example 14 is shown in Figure 10.

[0130] <Example 15> 0.1 g of a surface antifouling coating agent (manufactured by Daikin Industries, Ltd., product name: Optool DSX, active ingredient concentration: 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 (active ingredient concentration: 0.1% by mass). This fluorine treatment agent was applied to one main surface of a borosilicate glass (manufactured by SCHOTT, product name: D263 T eco) with dimensions of 76 mm × 76 mm × 0.21 mm. The glass substrate was then left at room temperature for 24 hours to dry the fluorine treatment agent coating, and then the glass surface was lightly wiped with a dust-free cloth containing Novec 7100 to remove excess fluorine treatment agent. A fluorine-treated substrate was thus prepared.

[0131] A light-absorbing composition according to Example 15 was prepared by the same method and conditions as in Example 1, except that the required compounds and their amounts were changed as shown 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 according to Example 15 was used instead of the light-absorbing composition according to Example 1, and the above-mentioned fluorine-treated substrate was used instead of the substrate. Next, this light absorber was peeled off the fluorine-treated substrate to obtain a film-like light absorber according to Example 15, which was used as an optical filter according to Example 15.

[0132] Tables 2 and 3 show the results of measuring or calculating the characteristic values ​​of the optical filter according to Example 15.

[0133] <Example 16> 4,500 g of copper acetate monohydrate and 240 g of tetrahydrofuran (THF) were mixed and stirred for 3 hours to obtain a copper acetate solution. Next, 2,400 g of the phosphate ester compound Prysurf A208N (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added to the obtained copper acetate solution and stirred for 30 minutes to obtain solution (16-A). Next, 40 g of THF was added to 2,800 g of n-butylphosphonic acid and stirred for 30 minutes to obtain solution (16-B). Solution (16-A) and solution (16-B) were mixed and stirred for 1 minute to obtain solution (16-C). Next, 120 g of toluene was added to this solution (16-C), and the mixture was stirred at room temperature for 1 minute to obtain solution (16-D). The (16-D) solution was placed in a flask and desolvated using a rotary evaporator (Tokyo Rikakikai Co., Ltd., model: N-1110SF) while being heated in an oil bath (Tokyo Rikakikai Co., Ltd., model: OSB-2100). The oil bath temperature was set to 105°C. After that, the desolvated solution was removed from the flask. In this way, a liquid composition (16-E) containing phosphonic acid and a light-absorbing compound with copper components dispersed in it was obtained.

[0134] A liquid curable resin (16-F) was prepared by mixing 7.54 g of silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KR-300), 0.18 g of 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 (manufactured by Kishida Chemical Co., Ltd., special grade) 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, and stirring for 30 minutes. Furthermore, a composition for light-absorbing film (16-G) was prepared by mixing the above liquid composition (16-E) and the liquid curable resin (16-F) and stirring for 30 minutes.

[0135] A light-absorbing film composition (16-G) was applied to an 80 mm × 80 mm area in the center of a fluorine-treated substrate prepared in the same manner as in Example 15, using a dispenser to form a coating film. After the obtained coating film was thoroughly dried at room temperature, it was placed in an oven and heated sufficiently in the range of room temperature to 85°C to allow the alkoxysilane reaction to proceed sufficiently and to volatilize the organic solvent contained in the light-absorbing film composition (16-G). Subsequently, post-curing was performed by leaving it in an environment of 85°C and 85% relative humidity for a further 24 hours to complete the reaction and to prepare a light absorber on the fluorine-treated substrate. Next, a film-like light-absorbing substrate (16-H) was obtained by peeling this light absorber from the fluorine-treated substrate. Figure 11A shows the transmission spectrum of the light-absorbing substrate (16-H). In addition, Tables 2 to 4 show the characteristic values ​​that can be observed from this transmission spectrum and the thickness of the film-like light-absorbing substrate (16-H).

[0136] The light-absorbing composition according to Example 16 was prepared using the same method and conditions as in Example 1, except that the required compounds and their amounts were changed as shown in Table 1. An optical filter according to Example 16, which has two light-absorbing layers, was fabricated using the same method and conditions as in Example 1, except that the light-absorbing composition according to Example 16 was used instead of that of Example 1, and a light-absorbing substrate (16-H) was used as the substrate. Figure 11B shows the transmission spectrum of the optical filter according to Example 16. In addition, Tables 2 and 3 show the results of measuring or calculating the various characteristic values ​​of the optical filter according to Example 16.

[0137] <Comparative Examples 1-3> Except for the changes in the required compounds and their amounts as shown in Table 1, the light absorbers for Comparative Examples 1 to 3 were prepared using the same method and conditions as in Example 1. Figure 12 shows the transmission spectrum of the optical filter for Comparative Example 3. The measurement and calculation results of each characteristic value that could be measured or calculated for the light absorbers for Comparative Examples 1 to 3 are shown in Tables 2 and 3.

[0138] Significant turbidity occurred in the light-absorbing composition of Comparative Example 1, and a transparent optical filter could not be fabricated. In Comparative Example 1, it is presumed that the aggregation suppression effect of the generated copper phosphonate compound was insufficient because the number of carbon atoms in the alkyl group directly bonded to the silicon atom in the added trifunctional alkoxysilane was small (6). Therefore, the amount of the same trifunctional alkoxysilane added was increased in Comparative Example 2, but significant turbidity still occurred. In Comparative Example 3, where the amount of the same trifunctional silane added was further increased, an optical filter could be fabricated. However, as shown in Figure 12, the transmittance in the visible light range of the optical filter of Comparative Example 3 was low, and the thickness of the light absorber in the optical filter of Comparative Example 3 was 157 μm. In addition, the haze of the light absorber in Comparative Example 3 was also very large at 12.96, and an optical filter with good properties could not be obtained. From these results, it is suggested that when the number of carbon atoms in the alkyl group of the trifunctional linear alkylsilane is less than 10, a sufficient aggregation suppression effect of copper phosphonate cannot be obtained, and it is difficult to fabricate an optical filter with good optical properties.

[0139] <Example 17> (Preparation of liquid precursor for anti-reflective coating formation) A liquid precursor A for forming an anti-reflective film (hereinafter referred to as anti-reflective film forming liquid composition A) was prepared by mixing 0.87 g of tetraethoxysilane (TEOS), a type of tetrafunctional silane; 1.33 g of methyltriethoxysilane (MTES), a type of trifunctional silane; 0.80 g of 0.3 wt% formic acid; 3.70 g of hollow silica particle-containing sol (manufactured by JGC Catalysts & Chemicals, product name: Thru-Ria 4110, silica solids content: approximately 25 wt%); and 27.3 g of ethanol. The mixture was reacted at 30°C for 1 hour and then at 35°C for 2 hours.

[0140] (Fabrication of optical filters with anti-reflective coatings) An anti-reflective coating-forming liquid composition A was applied to one side of an optical filter prepared under the same conditions and methods as in Example 15, with the application amount and conditions adjusted so that the film thickness after drying and curing was 120 nm. A spin coater was used for application, and the rotation speed and rotation time were also adjusted. The optical filter with anti-reflective coating-forming liquid composition A applied to one side was left to stand for about 1 minute to allow it to initially dry. Furthermore, the other side of the optical filter was also coated with anti-reflective coating-forming liquid composition A under the same conditions and methods. The optical filter with anti-reflective coating-forming composition A applied to both sides, which had been initially dried in this way, was left to stand in an oven heated to 85°C for 1 hour to allow the composition to react and solidify, thereby producing the optical filter according to Example 17. This optical filter had an anti-reflective coating on both sides. The transmission spectrum of the optical filter according to Example 17 is shown in Figure 13. The characteristic values ​​and calculated values ​​based on the transmission spectrum are shown in Table 5, and furthermore, the values ​​obtained by dividing the optical density OD value at each wavelength λ by the thickness of the light absorber are shown in Table 6.

[0141] <Example 18> (Preparation of liquid precursor for anti-reflective coating formation) 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 then at 35°C for 2 hours. Composition B for forming anti-reflective films was thus prepared.

[0142] (Fabrication of optical filters with anti-reflective coatings) Anti-reflective film-forming liquid composition B was applied to one side of an optical filter prepared under the same conditions and methods as in Example 15, with the application amount and conditions adjusted so that the film thickness after drying and curing was 250 nm. A spin coater was used for application, and the rotation speed and rotation time were also adjusted. The optical filter with anti-reflective film-forming liquid composition B applied to one side was left to stand for about 1 minute for initial drying. Furthermore, anti-reflective film-forming liquid composition B was applied to the other side of the optical filter under the same conditions and methods. The optical filter with anti-reflective film-forming composition B applied to both sides, which had been initially dried in this manner, was left to stand in an oven heated to an internal temperature of 85°C for 1 hour to allow the composition to react and solidify. Next, for the optical filter having layers of solidified anti-reflective film-forming composition B on both sides, anti-reflective film-forming liquid composition A was applied to one side, with the application amount and conditions adjusted so that the film thickness after drying and curing was 90 nm. A spin coater was used for application, and the rotation speed and rotation time were also adjusted. An optical filter coated with anti-reflective film-forming liquid composition A on one side was allowed to stand for approximately 1 minute to allow it to initially dry. The other side of the optical filter was then coated with anti-reflective film-forming liquid composition A under the same conditions and method. The optical filter, with anti-reflective film-forming composition A applied to both sides, was then placed in an oven heated to 85°C for 1 hour to allow the composition to react and solidify, thereby producing the optical filter according to Example 18. This optical filter had an anti-reflective coating on both sides. Figure 14 shows the transmission spectrum of the optical filter according to Example 18. Table 5 shows the characteristic values ​​and calculated values ​​based on the transmission spectrum, and Table 6 shows the optical density OD value at each wavelength λ divided by the thickness of the light absorber.

[0143] [Table 1A]

[0144] [Table 1B]

[0145] Table 2

[0146] Table 3

[0147] Table 4

[0148] Table 5

[0149] Table 6

Claims

1. At least one selected from the group consisting of an alkoxysilane containing a group having 10 or more carbon atoms, a hydrolysate of the alkoxysilane, and a polymer of the hydrolysate of the alkoxysilane, A light-absorbing compound, Light-absorbing composition.

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

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

4. The light-absorbing material, which is a solidified product of the light-absorbing composition, is the light-absorbing composition according to any one of claims 1 to 3, satisfying 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 η λ [μm -1 When expressed as ], 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 T A 460-600 When expressed as such, 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 a phosphate ester.

6. It is a light absorber, Average value T A 460-600 is 80% or more, Said average value T A 460-600 This is the average value of the transmittance in the wavelength range of 460 nm to 600 nm of the transmission spectrum obtained by incidenting light on the light absorber at an incident angle of 0°. η is the value obtained by dividing the optical density OD of the light absorber at wavelength λ by the thickness of the light absorber. λ [μm -1 When expressed as ], 0.009 ≤ η 380 and 0.008 ≤ η 750 Meets the requirements, Light absorber.

7. The light absorber according to claim 6, having a haze of less than 0.2%.

8. Average value T A 300-380 and the average value T A 750-1100 is, T A 300-380 ≤1.5% and T A 750-1100 Meeting the requirement of ≤2.0%, Said average value T A 300-380 This is the average value of the transmittance within the wavelength range of 300 nm to 380 nm of the transmission spectrum. Said average value T A 750-1100 This is the average value of the transmittance within the wavelength range of 750 nm to 1100 nm of the transmission spectrum. The light absorber according to claim 6 or 7.

9. An optical filter comprising a light absorber according to any one of claims 6 to 8.

10. The light absorber and the anti-reflective coating provided on the surface of the light absorber are included. The optical filter according to claim 9.

11. The optical filter according to claim 10, wherein the anti-reflective coating comprises one or more layers selected from the group consisting of (a), (b1), (b2), and (c) below. (a) Layer containing silsesquioxane and silica (b1) A layer containing silsesquioxane, silica, and hollow particles. (b2) A layer containing silsesquioxane, silica, and solid particles. (c) SiO 2 , TiO 2 Ta 2 O 3 , SnO 2 In 2 O 3 Nb 2 O 5 Si 3 N 4 TiN x and MgF 2 A layer containing at least one material selected from the group consisting of

12. The optical filter according to claim 11, wherein the layer (b1) comprises 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 (c) is composed of one or two or more layers made of different materials.

14. The anti-reflective coating includes the layer (b1) and the layer (b2), The refractive index of layer (b2) is higher than that of layer (b1). The optical filter according to any one of claims 11 to 13.

15. The optical filter according to any one of claims 11 to 14, wherein the layer (b1) comprises 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 (b2) comprises solid particles having a refractive index of 1.25 to 2.

75.

17. An ambient light sensor comprising a light absorber according to any one of claims 6 to 8.

18. An imaging device comprising a light absorber according to any one of claims 6 to 8.

19. To prepare a light-absorbing compound dispersion in which a light-absorbing compound containing 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 hydrolysate of the alkoxysilane, This includes removing a portion of the solvent from the light-absorbing compound dispersion. A method for producing a light-absorbing composition.

20. A method for producing a light-absorbing composition according to claim 19, wherein the solidified 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 solidified material is η λ [μm -1 When expressed as ], 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 T A 460-600 When expressed as such, 80% ≤ T A 460-600

21. This includes obtaining a light absorber by solidifying a light-absorbing composition coated on the surface of a substrate, The light-absorbing composition is A light-absorbing compound containing phosphonic acid and copper components, It comprises at least one selected from the group consisting of an alkoxysilane having a group having 10 or more carbon atoms, a hydrolysate of the alkoxysilane, and a polymer of the hydrolysate of the alkoxysilane, The light absorber has a thickness of 150 μm or less. A method for manufacturing a light absorber.

22. The method for manufacturing 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 η λ [μm -1 When expressed as ], 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 T A 460-600 When expressed as such, 80% ≤ T A 460-600

23. Light absorber and The light absorber comprises an anti-reflective coating provided on its surface, An optical filter that 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 η 2-λ [μm -1 When expressed as ], 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 T 2 A 460-600 When expressed as such, 90% ≤ T 2 A 460-600

24. 0.020 ≤ η 2-900 and 0.013 ≤ η 2-1100 The optical filter according to claim 23, wherein the following conditions are met.

25. The average transmittance within the wavelength range of 300 nm to 380 nm is T 2 A 300-380 The average transmittance in the wavelength range of 750 nm to 1100 nm is defined as T 2 A 750-1100 In that case, T 2 A 300-380 ≤1.5% and T 2 A 750-1100 ≤ 2.0%, Let the second ultraviolet cut-off wavelength at which the transmittance becomes 50% within the range of 350 nm to 460 nm be λ 2 0 UV and let the second infrared cut-off wavelength at which the transmittance becomes 50% within the range of 600 nm to 700 nm be λ 2 0 IR When this is the case, 390 nm ≦ λ 2 0 UV ≦ 450 nm and 600 nm ≦ λ 2 0 IR ≦ 680 nm The optical filter according to claim 23 or 24.

26. The optical filter according to any one of claims 23 to 25, wherein the anti-reflective coating comprises a layer containing silsesquioxane and silica.

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