Light absorbing composition, light absorber, optical filter, environmental light sensor, imaging device, method for producing light absorbing composition, and method for producing light absorber

Abstract

This light absorbing composition includes a silicon-containing compound α and a light-absorbing compound. The silicon-containing compound α is at least one selected from the group consisting of: an alkoxysilane including a group α-1 having at least 10 carbon atoms; and a hydrolyzate of the alkoxysilane.

Description

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

[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.

[0002] In an image capture device or ambient light sensor using a solid-state image sensor such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS), various optical filters are disposed in front of the solid-state image sensor. For example, in an image capture device, an optical filter may be used to obtain an image with good color reproducibility. In an ambient light sensor, an optical filter may be used to adjust the sensing of ambient light.

[0003] Generally, solid-state imaging devices have sensitivity over a wide wavelength range, from ultraviolet to infrared. However, human visual sensitivity is limited to wavelengths between approximately 380 nm and 780 nm, the so-called visible light range. Therefore, in order to bring the spectral sensitivity of the solid-state imaging device in an imaging device closer to the human visual sensitivity, a technique is known in which an optical filter is placed in front of the solid-state imaging device to block part of the infrared and ultraviolet light.

[0004] Among these, light-absorbing optical filters having a film or layer containing a light-absorbing agent have attracted attention. The transmittance characteristics of optical filters with a film containing a light-absorbing agent are less affected by the angle of incidence. Therefore, even when light is incident obliquely on an optical filter in an imaging device, for example, there is little change in color, there is little color unevenness within the surface, and good images with good reproducibility can be obtained. In addition, since light-absorbing optical filters do not use a light-reflecting film, the occurrence of ghosts or flares 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 advantageous in terms of miniaturizing and thinning imaging devices.

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

[0006] Patent Document 2 describes an optical filter having a light absorbing layer that contains a light absorber formed from a specific phosphonic acid and copper ions, but does not contain a specific phosphate ester. Patent Document 2 explains that the specific 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 having a UV-IR absorbing layer containing a UV-IR absorber capable of absorbing ultraviolet and infrared rays, which is formed by at least one acid selected from phosphonic acid and sulfonic acid and copper ions. This optical filter has a haze 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.

[0008] International Publication No. 2020 / 071461 International Publication No. 2019 / 093076 International Publication No. 2019 / 208518

[0009] The techniques described in Patent Documents 1 to 3 have room for reexamination from the viewpoints of thinness and optical properties. Therefore, the present invention provides a light-absorbing compound that is advantageous from the viewpoints of thinness and optical properties. The present invention also provides a light-absorbing body that is advantageous from the viewpoints of thinness and optical properties.

[0010] The present invention provides a light-absorbing composition comprising: at least one selected from the group consisting of alkoxysilanes containing a group having 10 or more carbon atoms, hydrolysates of the alkoxysilanes, and polymers of the hydrolysates of the alkoxysilanes; and a light-absorbing compound.

[0011] The present invention also provides a light absorber having an average value T A 460-600 is 80% or more, and the average value T A 460-600is the average value of the transmittance in the wavelength range of 460 nm to 600 nm of the transmission spectrum obtained by making light incident on the light absorber at an incident angle of 0°, and η is the value obtained by dividing the optical density OD of the light absorber at a wavelength λ by the thickness of the light absorber. λ [μm -1 ], 0.009≦η 380 and 0.008≦η 750 To provide a light absorber that satisfies the requirements of

[0012] The present invention also provides an optical filter comprising the above light absorber.

[0013] The present invention also provides an ambient light sensor including the above light absorber.

[0014] The present invention also provides an imaging device including the above light absorber.

[0015] The present invention also provides a method for producing a light-absorbing composition, the method comprising: 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 hydrolysate of the alkoxysilane; and removing a part of the solvent from the light-absorbing compound dispersion.

[0016] The present invention also provides a method for producing a light absorber, comprising solidifying a light absorbing composition coated on a surface of a substrate to obtain a light absorber, wherein the light absorbing composition comprises 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 hydrolysate of the alkoxysilane, and a polymer of the hydrolysate of the alkoxysilane, and the light absorber has a thickness of 150 μm or less.

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

[0018] The light-absorbing composition and light-absorbing material described above are advantageous in terms of thinness and optical properties.

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

[0020] With the global spread of information terminals such as smartphones equipped with camera modules, there is an increasing demand for thinner optical filters installed 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 at wavelengths of 750 nm to 1080 nm, but its light absorption characteristics in this wavelength range are far from sufficient. For example, it is understood to be difficult to achieve a transmittance of 1% or less at wavelengths of 750 nm to 1080 nm with a thickness of approximately 110 μm. In other words, it is understood to be difficult to achieve sufficient light absorption performance with an optical filter having a light absorption layer containing copper phosphonate and an organic dye with a thickness of approximately 110 μm, even when the organic dye is used in combination.

[0021] The optical filter described in Patent Document 2 is promising in that it does not contain a phosphate ester, but it is difficult to say that it has sufficient characteristics from the viewpoint of achieving both thinness and desired optical properties. In addition, since it does not contain a phosphate ester, there is a possibility that some of the copper phosphonate will aggregate, reducing transmittance in the visible range.

[0022] Patent Document 3 describes the content of the copper component contained in the light-absorbing compound and the viscosity of the liquid light-absorbing composition that is a precursor of the UV-IR absorbing layer. The UV-IR absorbing layer described in Patent Document 1 has a haze value of 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 increased.

[0023] As a result of extensive research, the present inventors have newly discovered a light-absorbing compound that is advantageous from the viewpoint of realizing desired optical properties such as a transmittance close to the human luminosity curve and low haze even when the compound is thin. In addition, they have completed a novel light absorber that is advantageous from the viewpoint of realizing desired optical properties such as a transmittance close to the human luminosity curve and low haze.

[0024] Hereinafter, embodiments of the present invention will be described. Note that the following description is for illustrative purposes only and the present invention is not limited to the following embodiments.

[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 such alkoxysilanes, and polymers of such alkoxysilane hydrolysates. The alkoxysilane hydrolysates are silicon compounds having silanol groups (—Si—OH) generated by the hydrolysis of the alkoxysilane. The polymers of the alkoxysilane hydrolysates are compounds containing siloxane bonds (—O—Si—O—) formed by 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 cause steric hindrance during aggregation of the light-absorbing compound. For this reason, for example, when a light-absorbing compound containing a complex structure is formed, the generation of aggregates of the light-absorbing compound is likely to be prevented. This allows the light-absorbing compound to be uniformly dispersed in the light-absorbing composition, and a light absorber produced using the light-absorbing composition is likely to achieve desired optical properties, such as a transmission spectrum corresponding to the human visual sensitivity curve and low haze. The alkoxysilane containing the group α-1 is represented, for example, by the following formula (1): In formula (1), n ​​is 1, 2, or 3; 11 is a group containing at least a carbon atom (C) and a hydrogen atom (H), and R 11 At least one of R is a group α-1 having 10 or more carbon atoms. 12 is a group containing at least a carbon atom (C) and a hydrogen atom (H), and R 11 may be the same as R 11 may be different from R 11 4-n Si(OR 12 ) n Formula (1)

[0026] The light-absorbing compound is not limited to a specific compound. The light-absorbing compound may be, for example, a compound containing a phosphonic acid and a copper component, a compound containing a phosphate ester and a copper component, or a compound containing another phosphoric acid compound and a copper component. Examples of other phosphoric acid compounds are phosphoric acid, phosphorous acid, and phosphinic acid. The phosphoric acid-containing compound may be M x Cuy P.O. z (M may be absent or represents a metal element other than Cu, and x, y, and z are real numbers.) Furthermore, when a light-absorbing compound containing a phosphate compound such as phosphonic acid, phosphate ester, or phosphoric acid and a copper component is produced, a portion of the anion of the copper component, particularly the compound that serves as a raw material for copper ions, may be contained 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 contained 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 contained 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 compounds or elements other than these. 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 include tungsten oxide, indium tin oxide (ITO), and antimony tin oxide. Examples of organic dyes are diimmonium-based compounds, cyanine-based compounds, squarylium-based compounds, phthalocyanine-based compounds, and pyrrolopyrrole-based compounds.

[0027] The light-absorbing compound is preferably a compound containing phosphonic acid and a copper component, a compound containing a phosphate ester and a copper component, a compound containing phosphoric acid and a copper component, a compound containing sulfonic acid and a copper component, or a complex of any of these compounds. In this case, the light-absorbing compound is likely to have a wide absorption band in the infrared region, and the light-absorbing composition is promising as a material for a filter that blocks light in a predetermined wavelength range by absorption alone.

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

[0029] Phosphonic acid, phosphate ester, and phosphoric acid are all oxides containing a phosphorus atom (P) and an oxygen atom (O). They 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 acetic acid component (CH3COO) contained in the raw material may be added to the light-absorbing compound. - or CH3COOH) or benzoic acid component (C6H5COO - In these light-absorbing compounds, a portion of the copper ion or a copper complex containing a phosphorus compound such as phosphonic acid and a copper component may be coordinated. Furthermore, the copper compound that is the raw material for the copper component may be a hydrate, and the raw material may contain water molecules.

[0030] When the light-absorbing compound contains a phosphonic acid, the phosphonic acid is not limited to a specific phosphonic acid. Phosphonic acids are, for example, represented 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 a light absorber produced using the light-absorbing composition is likely to extend to a wavelength of around 700 nm, and the light absorber is likely to have the desired transmittance characteristics. Phosphonic acids represented by formula (a) are referred to as alkylphosphonic acids.

[0031]

[0032] Examples of alkylphosphonic acids are methylphosphonic acid, ethylphosphonic acid, normal (n-)propylphosphonic acid, isopropylphosphonic acid, normal (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, a halogenated aryl group in which at least one hydrogen atom in the aryl group is substituted with a halogen atom, a group in which at least one hydrogen atom in the aryl group is substituted with a nitro group, or a group in which at least one hydrogen atom in the aryl group is substituted with a hydroxy group. The aryl group is, for example, a phenyl group. The halogenated aryl group is, for example, a halogenated phenyl group. This makes it easier for a light absorber produced using the light-absorbing composition to have the desired transmittance characteristics. The phosphonic acid represented by formula (b) is called an arylphosphonic acid.

[0034]

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

[0036] The light-absorbing compound may contain only alkylphosphonic acid, only arylphosphonic acid, or both alkylphosphonic acid and arylphosphonic acid as the 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 the arylphosphonic acid may be bound to a copper component.

[0037] When the light-absorbing compound contains a copper component, the copper component is a concept that encompasses copper ions, copper complexes, copper-containing compounds, etc. The copper component may have good absorption properties for a part of light in the near-infrared region and high transmittance in the visible light region with wavelengths of 450 nm to 680 nm. For example, although details are omitted, divalent copper ions Cu 2+In the case of copper ions, when they have a hexacoordinated complex structure, they absorb light of wavelengths with corresponding energy levels in connection with the transition of electrons between d orbitals with different energy levels. Divalent copper ions absorb light over a relatively broad wavelength range in the infrared range, and are therefore thought to exhibit valuable light absorption functions as filters used in the field of digital photography. The width and intensity of the absorption band largely depend on the structure or properties of the ligands coordinated to the copper ions. For these reasons, it is desirable to use light absorbers or optical filters containing compounds in which phosphorus compounds, such as phosphonic acid and phosphate esters, are coordinated to copper ions to correct for luminous efficiency.

[0038] The source of the copper component contained in the light-absorbing compound is not limited to a specific substance. Examples of the copper component source include an anhydrous or hydrated copper salt of an organic acid, such as copper acetate, copper benzoate, copper pyrophosphate, and copper stearate, or a mixture thereof. Among these, copper acetate or copper benzoate is preferably used. Furthermore, these copper salts may be used alone, or multiple copper salts or a mixture thereof may be used.

[0039] The light-absorbing composition may contain at least one silicon-containing compound β selected from the group consisting of alkoxysilanes represented by the following formula (2) and hydrolysates of the alkoxysilanes: In formula (2), m is an integer of 3 or 4, and R 01 and R 02 may be the same or different, and R 01 and R 02are groups containing 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, only a tetrafunctional alkoxysilane, or both a trifunctional alkoxysilane and a tetrafunctional alkoxysilane as the silicon-containing compound β. The silicon-containing compound may be an alkoxysilane as a monomer, or may be a compound obtained by hydrolyzing a portion of an alkoxysilane. The silicon-containing compound β may contain a compound containing a siloxane bond formed by condensation polymerization of a portion of an alkoxysilane hydrolyzate. R 01 4-m Si(OR 02 ) m Formula (2)

[0040] The inclusion of the silicon-containing compound β represented by formula (2) in the light-absorbing composition facilitates the formation of a network when the light-absorbing composition is solidified. For example, when a light absorber is produced using the light-absorbing composition, a siloxane bond (—Si—O—Si—) is formed by treating the composition so that the hydrolysis reaction and condensation polymerization reaction of the alkoxysilane occur sufficiently. This facilitates the formation of a siloxane bond (—Si—O—Si—). This facilitates the formation of a light absorber with good moisture resistance. In addition, the light absorber has good heat resistance. This is because the siloxane bond has higher bond energy and is more chemically stable than bonds such as —C—C— and —C—O— bonds, and is therefore superior in heat resistance and moisture resistance. From the viewpoint of improving the density of the light absorber, the light-absorbing composition desirably contains, as the silicon-containing compound β, a tetrafunctional alkoxysilane in which m = 4 in formula (2). R 01 and R 02 may be a hydrocarbon group having 1 to 8 carbon atoms, or may be a group containing an aryl group. In addition, in formula (2), the inclusion of a trifunctional alkoxysilane in which m=3 in addition to a tetrafunctional alkoxysilane in which m=4 can provide flexibility to the light absorber.

[0041] As described above, the light-absorbing composition contains a silicon-containing compound α as one type of the silicon-containing compound. The group α-1 in the silicon-containing compound α is not limited to a specific group as long as it has 10 or more carbon atoms. The group α-1 may be an alkyl group or a substituted alkyl group in which at least one hydrogen atom in the alkyl group is substituted with a halogen atom, a nitro group, or an amino group. In this case, the alkyl group and the substituted alkyl group may or may not have a branched carbon chain.

[0042] The group α-1 may have a phenyl group or a substituted phenyl group in which at least one hydrogen atom in the phenyl group is substituted with a halogen atom, a nitro group, or an amino group. The group α-1 may have a reactive functional group such as a vinyl group, an epoxy group, a carbonyl group, an ester group, an amino group, a nitrile group, or a hydroxy group.

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

[0044] When the 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 a compound for imparting dispersibility, such as a polyoxyalkyl phosphate ester, in the light-absorbing composition.

[0045] In the 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 the light-absorbing composition, the silicon-containing compound α, i.e., a difunctional alkoxysilane, a trifunctional alkoxysilane, or a hydrolysate thereof, may be contained together with a tetrafunctional alkoxysilane represented by formula (2), a trifunctional alkoxysilane, or a hydrolysate thereof.

[0046] The light-absorbing composition may not contain a curable resin. This is because the silicon-containing compound α polymerizes to solidify the light-absorbing composition while maintaining the light-absorbing compound in a desired state, or the silicon-containing compound β also functions as a network former and polymerizes to solidify the light-absorbing composition. When the light-absorbing composition contains a tetrafunctional alkoxysilane contained in the alkoxysilane represented by formula (2), improved density or hardness of the light absorber is 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. Furthermore, the light-absorbing composition may be solidified as a dry gel by removing the solvent or by-products contained in the light-absorbing composition containing the alkoxysilane or its hydrolysate by evaporation or the like. It is not possible to determine which action is dominant, but various actions and processes are thought to be involved, including the dispersion action of the light-absorbing compound.

[0047] The content of the silicon-containing compound α in the light-absorbing composition is not limited to a specific value. For example, when the light-absorbing compound contains a copper component, the ratio r of the amount of silicon atoms contained in the silicon-containing compound α to the amount of the copper component is CS is 0.30 or more on a molar basis. In this case, aggregates of the light-absorbing compound are less likely to occur in the light-absorbing composition. CSThe ratio r is preferably 0.35 or more, and more preferably 0.40 or more. CS is, for example, 2.80 or less. In this case, it is easy to reduce the thickness of the light absorber obtained using the light-absorbing composition, which is easy to contribute to reducing the height of an element or device including the light absorber. CS is preferably 2.50 or less, and more preferably 2.20 or less.

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

[0049] The alkoxysilane containing the group α-1 is not limited to a specific alkoxysilane. Examples of the alkoxysilane containing the group α-1 include n-decyltrimethoxysilane, n-undecyltrimethoxysilane, n-dodecyltrimethoxysilane, n-tridecyltrimethoxysilane, n-tetradecyltrimethoxysilane, n-pentadecyltrimethoxysilane, n-hexadecyltrimethoxysilane, n-heptadecyltrimethoxysilane, n-octadecyltrimethoxysilane, n-nonadecyltrimethoxysilane, and n-eicosyltrimethoxysilane. Further examples of alkoxysilanes containing the group α-1 are n-decyltriethoxysilane, n-undecyltriethoxysilane, n-dodecyltriethoxysilane, n-tridecyltriethoxysilane, n-tetradecyltriethoxysilane, n-pentadecyltriethoxysilane, n-hexadecyltrimethoxysilane, n-heptadecyltrimethoxysilane, n-octadecyltrimethoxysilane, n-nonadecyltrimethoxysilane, and n-eicosyltrimethoxysilane. Further examples of alkoxysilanes containing the group α-1 include n-decylmethyldiethoxysilane, n-undecylmethyldiethoxysilane, n-dodecylmethyldiethoxysilane, n-tridecylmethyldiethoxysilane, n-tetradecylmethyldiethoxysilane, n-pentadecylmethyldiethoxysilane, n-hexadecylmethyldiethoxysilane, n-heptadecylmethyldiethoxysilane, n-octadecylmethyldiethoxysilane, n-nonadecylmethyldiethoxysilane, and n-eicosylmethyldiethoxysilane. Further examples of alkoxysilanes containing reactive functional groups include 8-glycidoxyoctyltrimethoxysilane and 8-methacryloxyoctyltrimethoxysilane.

[0050] The light-absorbing composition may contain an alkoxysilane other than an alkoxysilane containing a group α-1. The light-absorbing composition may contain a silicon-containing compound β, which is at least one compound selected from the group consisting of an alkoxysilane represented by formula (2), a hydrolysate of the alkoxysilane, and a condensation polymer of the hydrolysate 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 the organic solvent 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 are dichlorobenzene, heptanone, cyclopentanone, cyclohexanone, cyclohexane, dimethylformamide, dimethylacetamide, toluene, tetrahydrofuran (THF), and oxetane.

[0052] The light-absorbing composition may contain a phosphate ester. For example, when the light-absorbing compound contains phosphonic acid, the phosphate ester is a compound containing a phosphorus atom and an oxygen atom, similar to phosphonic acid, and therefore, good compatibility between the phosphate ester and the phosphonic acid is expected. The phosphate ester may function as a dispersant for the light-absorbing compound, or a portion of the phosphate ester may exist in a state in which 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 the phosphate ester 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 may also absorb light of a predetermined wavelength.

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

[0054] On the other hand, the light-absorbing composition may be substantially free of a phosphate ester. The presence of silicon-containing compound α containing group α-1 in the light-absorbing composition may allow 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 silicon-containing compound α may be 3.0 or less on a molar basis, or the light-absorbing composition may be completely free of a phosphate ester.

[0055] As described above, the light-absorbing composition may not contain a curable resin other than the silicon-containing compound. Alternatively, 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 the curable component include a curable resin, a curable polymer, and a monomer, dimer, or oligomer that is a precursor of the curable polymer. The curable component can 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 a light-absorbing compound containing a phosphonic acid and a copper component. In addition, the curable resin is preferably one that can be applied to a predetermined object to form a coating film by a coating method such as spin coating, spraying, dipping, or dispenser application. The curable resin is preferably one that has a smooth surface formed by curing the curable resin and has a transmission spectrum of 90% or more at wavelengths of 450 nm to 800 nm when the curable resin is cured and has a thickness of 1 mm. Examples of the curable resin include cyclic polyolefin resins, epoxy resins, polyimide resins, modified acrylic resins, silicone resins, and polyvinyl resins such as PVB, or precursors thereof. These curable resins may be used alone or in combination.

[0056] The light-absorbing composition may contain an ultraviolet absorber that absorbs a portion of ultraviolet light. The ultraviolet absorber is not limited to a specific compound. For example, the ultraviolet absorber is a compound that does not have both a hydroxy group and a carbonyl group in one molecule. For example, the curing of the light-absorbing composition can be promoted by the coordination of a reactant or precursor at a specific position in the molecule of the silicon-containing compound α. For example, the presence of a group that is easily coordinated with a substance other than the substance subjected to the reaction for curing the light-absorbing composition may weaken the action of the catalyst. In particular, both hydroxy groups and carbonyl groups have high electron donating properties, and it is thought that the silicon-containing compound α reacts or coordinates with an ultraviolet absorber having these groups, resulting in the formation of a complex. In this case, the ultraviolet absorption properties inherent to the ultraviolet absorber may change. If the ultraviolet absorber is a compound that does not have both a hydroxy group and a carbonyl group in one molecule, the silicon-containing compound α is less likely to form a complex with the ultraviolet absorber, and the ultraviolet absorption properties of the ultraviolet absorber are more likely to be exhibited. The ultraviolet absorber may contain only one of a hydroxy group and a carbonyl group in one molecule.

[0057] The UV absorber is preferably selected from the viewpoints of absorbing light in a desired wavelength range, being compatible with a specific solvent, dispersing well in the light-absorbing composition, and having excellent environmental resistance. Examples of UV absorbers include benzophenone-based compounds, benzotriazole-based compounds, salicylic acid-based compounds, and triazine-based 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 contains, for example, a predetermined amount of alkoxysilane. For example, silicon-containing compound α may be contained in the light-absorbing composition as an alkoxysilane. In the light-absorbing composition, hydrolysis of an alkoxysilane that corresponds to the silicon-containing compound α or an alkoxysilane that does not correspond to the silicon-containing compound α may occur. Due to this hydrolysis, the light-absorbing composition may contain water. The light-absorbing composition may contain an appropriate amount of water depending on the application, function, and storage environment of the light-absorbing composition.

[0059] On the other hand, in the process of solidifying the light-absorbing composition to produce a light absorber, a humidification treatment may be performed as a post-cure. In the humidification treatment, molecular-level water components are incorporated into the light absorber or its precursor, which may promote the hydrolysis of the alkoxysilane and the reaction of forming a siloxane bond after hydrolysis. For example, when a process including a humidification treatment is employed, the light-absorbing composition may be substantially free of water. In this case, the light-absorbing composition may contain water components that are pre-coordinated in a compound such as a hydrate, or water components that are inevitably contained without being intentionally added.

[0060] The method for producing the light-absorbing composition is not limited to a specific method. For example, the method for producing the light-absorbing composition includes the following methods (I), (II), and (III): (I) 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; (II) 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 (III) removing a portion of the solvent from the light-absorbing compound dispersion.

[0061] As shown in FIGS. 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 has a group α-1 and contains a polysiloxane containing a siloxane bond. As shown in FIG. 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 FIG. 1B, an optical filter 1b may be constituted by the light absorber 10 and a substrate 20.

[0062] In the light absorber 10, the average value T A 460-600 is 80% or more. A 460-600 is the average value of the transmittance in the wavelength range of 460 nm to 600 nm of the transmission spectrum obtained by irradiating the light absorber 10 with light at an incident angle of 0°. The value obtained by dividing the optical density OD of the light absorber 10 at a wavelength λ by the thickness of the light absorber 10 is η λ [μm -1 The optical density OD is expressed as OD = -log 10 It is expressed by [T(λ) / 100], where T(λ) is a numerical value representing the transmittance at wavelength λ in %. In this case, in the light absorber 10, 0.009≦η 380 and 0.008≦η 750 The above requirements are satisfied. As a result, even if the light absorber 10 is thin, it is likely to have a transmittance close to the human visual sensitivity curve. 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 absorbing it. In addition, a thin light absorber 10 can be used as an infrared cut filter or an ultraviolet cut filter. This makes it easy to make optical filters arranged near sensors or light-receiving surfaces thin, and the light absorber 10 can contribute to reducing the height of image capture 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 when light is incident on the light absorber 10 at an incident angle of 0° using a spectrophotometer or the like.

[0063] In the light absorber 10, the average value T A 460-600is preferably 82% or more, and more preferably 84% or more. This increases the transmittance of the light absorber 10 in the visible light range, and makes the light absorber 10 more likely to have a transmittance close to the visibility curve of humans.

[0064] In the light absorber 10, it is desirable that 0.012≦η 380 In the light absorber 10, the requirement of 0.010≦η is preferably satisfied. 750 This satisfies the above requirement. Light belonging to wavelengths other than visible light can be blocked more effectively, and the light absorber 10 is more likely to have a transmittance close to the human visual sensitivity curve.

[0065] The light absorber 10 has a haze (cloudiness) of, for example, less than 0.2%. For example, an optical filter incorporated into an imaging device is designed so that its transmission spectrum and reflection spectrum 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 within the optical filter or light absorber, resulting in cloudy or opaque optical characteristics. This may affect the formation of a sharp image. On the other hand, when the light absorber 10 has a haze of less than 0.2%, the transparency of the light absorber 10 is high, and, for example, when the light absorber 10 is used in an imaging device, high-quality images are likely to be acquired by the imaging device. The haze may be measured using the light absorber 10 alone, or 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 refractive index of, for example, 0.018≦η 900 and 0.013≦η 1100 The light absorber 10 may satisfy the requirement of 0.016≦η 800 and 0.013≦η 1000 This makes it easier for the light absorber 10 to have a transmittance close to the human visibility curve even if the light absorber 10 is thin.

[0068] The light absorber 10 preferably has a refractive index of 0.020≦η 900 and 0.015≦η 1100 and 0.018≦η 800 and 0.018≦η 1000 The requirements of the above may be met.

[0069] The light absorber 10 is, for example, T A 300-380 ≦1.5% and T A 750-1100 Meets the requirement of ≦2.0%. A 300-380 is the average value of the transmittance in the wavelength range of 300 nm to 380 nm of the transmission spectrum obtained by irradiating light onto the light absorber 10 at an incident angle of 0°. A 750-1100 is the average value of the transmittance in the wavelength range of 750 nm to 1100 nm of the transmission spectrum. In this case, the light absorber 10 is more likely to have a transmittance close to the human visual sensitivity curve.

[0070] The light absorber 10 is preferably T A 300-380 ≦1.2%, more preferably T A 300-380 The light absorber 10 preferably satisfies the requirement of T A 750-1100 ≦1.5% or less, 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 ≦450 nm requirement is met, and 600 nm≦λ 0 IR The requirement of λ≦680 nm may be met. 0 UV is the first ultraviolet cutoff wavelength at which the transmittance is 50% in the wavelength range of 350 nm to 460 nm. 0 IRis the first infrared cutoff wavelength at which the transmittance is 50% in the wavelength range of 600 nm to 700 nm. 0 UV The requirement of ≦450 nm is met, and more preferably 395 nm≦λ 0 UV In the light absorber 10, the requirement of 605 nm≦λ≦450 nm is preferably met. 0 IR The requirement of λ≦680 nm is met, and more preferably λ≦610 nm 0 IR The requirement of ≦680 nm is met.

[0072] The light absorber 10 is, for example, R A 450-550 ≦10% requirement, R A 700-1000 Meets the requirement of ≦8%. A 450-550 is the average value of reflectance in the wavelength range of 450 nm to 550 nm. 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 light of 300 nm to 1200 nm onto the light absorber 10 at an incident angle of 5°. When the light absorber 10 absorbs a part of light of a specific wavelength so as to satisfy these requirements, for example, in an imaging device incorporating the light absorber 10, reflection or scattering of reflected light occurs inside the housing of the imaging device or at the aperture, and it is possible to suppress a decrease in the contrast of a captured image, such as ghosting or flare.

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

[0074] The light absorber 10 is, for example, R 380 <R 350 Meets the requirements of R 380 is the reflectance at a wavelength of 380 nm, and R 350is the reflectance at a wavelength of 350 nm. In this case, the occurrence of ghosts or flares that lead to a decrease in image contrast is more likely to be suppressed.

[0075] The transmittance, η λ , haze, and reflectance requirements may be met in an optical filter comprising the light absorber 10 .

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

[0077] As shown in Fig. 1A, when the optical filter 1a is constituted solely by the light absorber 10, the thickness of the optical filter 1a is likely to be small, and the optical filter 1a can be in the form of a film. Therefore, the optical filter 1a is likely to contribute greatly to reducing the height of a device incorporating the optical filter 1a. On the other hand, as shown in Fig. 1B, an optical filter 1b including the light absorber 10 and a substrate 20 may be provided. In this case, the rigidity or mechanical strength of the optical filter 1b is likely to be high, and the optical filter 1b can be provided as a rigid optical filter.

[0078] The surface of the substrate 20 can be formed of, for example, glass, resin, or metal. The type and optical properties of the substrate 20 are determined based on the desired transmittance, η λThe substrate 20 is not limited to a specific embodiment as long as it has the desired haze and reflectance. Additionally, the shape of the substrate 20 is not limited to a specific shape. As shown in FIG. 1B , the substrate 20 is, for example, flat. In this case, the light-absorbing composition can be easily applied, and the optical filter 1b is likely to have high versatility. On the other hand, the substrate 20 may include a curved surface, or a convex or concave surface. The substrate 20 may have a shape other than a plate. The substrate 20 may be an optical element, and examples of optical elements include lenses, polarizers, prisms, reflective elements, and diffraction gratings. These optical elements may include curved and flat surfaces. Other examples of the substrate 20 include photoelectric conversion elements such as photodiodes and phototransistors, image sensors in which a large number of photoelectric conversion elements such as CCDs or CMOSs ​​are arranged, and image sensors equivalent to these image sensors. In some cases, the light absorber 10 may be directly disposed 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 likely to be 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 material for the substrate 20 having such transmission characteristics is glass. The substrate 20 may be a transparent glass substrate containing silicate glass. Examples of silicate glass include 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 fluorophosphate glass containing a coloring component such as Cu or Co. The glass containing a coloring component is, for example, infrared absorbing glass, in which case the substrate 20 itself has light absorption properties. When the substrate 20 is a substrate containing infrared absorbing glass, adjusting the light absorption and transmission spectra of both the light absorber 10 and the substrate 20 makes it easier for the optical filter 1b to have desired optical characteristics. In addition, the degree of freedom in designing the optical filter 1b is easily increased.

[0080] The substrate 20 may contain a resin. Examples of resins contained in the substrate 20 include cycloolefin resins such as norbornene resins, polyarylate resins, acrylic resins, modified acrylic resins, polyimide resins, polyetherimide resins, polyolefin resins, polysulfone resins, polyethersulfone resins, polycarbonate resins, and silicone resins. Resins are easier to process and mold than glass. Therefore, when the substrate 20 contains a resin, it is easier to obtain substrates 20 of various shapes, such as optical elements.

[0081] 1C , the optical filter 1c includes 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 whose surface the light absorber 10 can be arranged. The light-absorbing substrate 21 may include glass containing the above-mentioned coloring component, or may be a substrate made of a resin that contains a dye, a pigment, and a coloring material.

[0082] An optical filter including a light absorber 10 may include an antireflection film or a light reflection reduction film for preventing or reducing reflection of light incident on the surface of the optical filter. In this case, the antireflection film or the light reflection reduction film (hereinafter collectively referred to as an "antireflection film") forms the surface of the optical filter. As shown in FIG. 1D , an optical filter 1d includes a light absorber 10 and antireflection films 31a and 31b provided on the surface of the light absorber 10. The antireflection films 31a and 31b are arranged along the surface of the light absorber 10. For example, when an optical filter includes a transparent substrate and a light absorber 10 arranged on the transparent substrate, antireflection films may be arranged on the surface of the light absorber 10 and on the surface of the transparent substrate that is not in contact with the light absorber 10. Such a light absorber provided with an antireflection film and an optical filter including such a light absorber and an antireflection film are also within the scope of the present invention.

[0083] The antireflection film can increase the transmittance of the light absorber 10 or the optical filter, for example, in a wavelength band (transmission wavelength band) in which light passes through the light absorber 10 or the optical filter including the light absorber 10. The transmission wavelength band is, for example, a wavelength band in which the transmittance is 50% or more in the transmission spectrum of the light absorber or the optical filter at an incident angle of 0°.

[0084] When an antireflection film 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 at wavelengths of 400 nm to 600 nm is, for example, 1% or less in the reflection spectrum obtained by irradiating light with a wavelength of 300 nm to 1200 nm at an incident angle of 5°. This reflectance is desirably 0.5% or less, and more desirably 0.25% or less.

[0085] In this reflection spectrum, the average value of reflectance in the wavelength range of 700 nm to 1200 nm is, for example, 1% or less. In this case, ghosts or flares are less likely to occur in images obtained by reflecting a portion of infrared light. This average value of reflectance is preferably 0.5% or less, and more preferably 0.25% or less.

[0086] When an anti-reflection film is formed on the light absorber 10 or the like, in a reflection spectrum obtained by irradiating light with a wavelength 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 an optical filter including the light absorber 10 is large, the reflectance of the light absorber 10 or an optical filter including the light absorber 10 is low. This reflectance is desirably 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 an optical filter including the light absorber 10 is large, the reflectance of the light absorber 10 or an optical filter including the light absorber 10 is low. This reflectance is desirably 1.5% or less.

[0087] The anti-reflection film is not limited to a specific film. The anti-reflection film includes at least one layer selected from the group consisting of (a), (b), and (c) below. The anti-reflection film may include two or more layers selected from this group. In FIG. 1D, each of the anti-reflection films 31a and 32a is shown as an example of a single layer, but this figure is functionally depicted to distinguish each anti-reflection film from the light absorber 10. In reality, the anti-reflection films 31a and 32a may be single-layer films formed as a single layer made of approximately the same material, or multi-layer films formed as multiple layers made of multiple different materials. (a) A layer formed by a sol-gel method using a reactive material containing silicon. (b) A layer formed by a sol-gel method using a reactive material containing silicon, and further including fine particles. (c) A layer formed by a physical film formation method such as vacuum deposition and sputtering.

[0088] Regarding the layer (a) above, the silicon-containing reactive material is not limited to a specific material. The reactive material preferably includes a trifunctional silane such as methyltriethoxysilane (MTES) and a tetrafunctional silane such as tetraethoxysilane (TEOS). The tetrafunctional silane is important for forming a layer with a strong and dense skeleton. On the other hand, using a tetrafunctional silane alone makes it difficult to control the reactivity and results in poor polarity selectivity. In addition, cracking is likely to occur. The addition of a trifunctional silane improves the flexibility of the silica skeleton, enhances polarity control, and reduces cracking. As a result, the refractive index required for the anti-reflective coating can be adjusted by adjusting the polarity. The organic functional group contained in the trifunctional silane is not limited to a specific functional group. The organic functional group is, for example, a methyl group. In this case, a homogeneous liquid and coating film can be easily formed when the trifunctional silane is combined with the tetrafunctional silane. The ratio of the amount of trifunctional silane to the amount of tetrafunctional silane is not limited to a specific value. The molar ratio is, for example, 1 / 3 to 5. This allows the trifunctional silane to suppress the occurrence of cracks in the anti-reflective coating, while the tetrafunctional silane allows the formation of a strong skeleton. The silicon-containing reactive material may further contain a difunctional silane.

[0089] The trifunctional silane is not limited to a specific silane. Examples of trifunctional silanes include methyltriethoxysilane, methyltrimethoxysilane, ethyltriethoxysilane, ethyltrimethoxysilane, propyltriethoxysilane, propyltrimethoxysilane, butyltriethoxysilane, butyltrimethoxysilane, pentyltrimethoxysilane, pentyltriethoxysilane, hexyltriethoxysilane, and hexyltrimethoxysilane, and may also be trifunctional silanes having an alkyl group directly bonded to a silicon atom (Si). The tetrafunctional silane is not limited to a specific silane. 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, trifunctional silanes can become (poly)silsesquioxanes, and tetrafunctional silanes can change to a silica structure through condensation polymerization of the hydrolyzed products.

[0091] Since the refractive index of (poly)silsesquioxane and silica is low, around 1.46, a layer having a low refractive index can be easily formed. A layer containing at least one selected from the group consisting of (poly)silsesquioxane and silica is suitable as a layer to be included in the light absorber 10 or the antireflection film of an optical filter including the light absorber 10.

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

[0093] Regarding the layer (b), the layer containing the silicon-containing reactive material, the hydrolyzate of this reactive material, or the condensation polymer of this hydrolyzate contains particles. The particles contain, 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 a layer containing silica or (poly)silsesquioxane, these act as a binder surrounding the particles. This improves the bonding strength between the particles and the binder via silanol groups, etc., which tends to increase the weather resistance of the antireflective coating and is expected to improve the reliability of the antireflective coating.

[0094] The particles contained in layer (b) may be hollow particles. A layer containing hollow particles, silsesquioxane, and silica is referred to as layer (b1) to distinguish it from a layer containing solid particles, which will be described later. Hollow particles contain empty spaces inside, so 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 the particle diameter (median diameter) at which the cumulative distribution of smallest particles reaches 50% in a number-based particle size distribution curve measured according to a laser diffraction / scattering method using, for example, a laser diffraction / scattering particle size analyzer. Examples of laser diffraction / scattering particle size analyzers that can be used include the "LA-960V2 Series" laser diffraction / scattering particle size distribution analyzer manufactured by Horiba, Ltd. The average particle diameter of the fine particles may be determined by observing a cross section of the structure including the (b1) layer under a scanning electron microscope (SEM) at a magnification of 100,000 times, measuring the particle diameters of the fine particles contained within the field of view or within a predetermined range (for example, 500 nm square), and then calculating the average value. This method may be used particularly when determining the diameters of the fine particles contained in a solidified or solid layer. The content of the fine particles in the (b1) layer is, for example, 5% to 95% by mass. The content of the fine particles in the (b1) layer is, for example, 30% to 99% by volume. The content of the fine particles in the (b1) layer is determined by observing a cross section of a structure including the (b1) layer at 100,000 times magnification using an SEM, and then calculating the ratio of the volume of the fine particles to the volume of the (b1) layer. Generally, the greater the proportion of hollow fine particles in the (b1) layer, the lower the refractive index of the layer tends to be. The content of the fine particles in the (b1) layer may be, for example, 75% to 99% by volume.

[0095] A layer containing such hollow particles and at least one selected from the group consisting of silica and (poly)silsesquioxane tends to have a very low refractive index. For example, the refractive index of the (b1) layer is, for example, 1.00 to 1.45. The hollow particles may be hollow silica particles, such as Sururia 4110 or 1110 manufactured by JGC Catalysts and Chemicals. The refractive index of the (b1) layer may be determined as follows: A laminate is prepared including a substrate having a known refractive index within a specific wavelength range and a layer (b1) disposed on the surface of the substrate, and the reflection spectrum of the laminate is measured. Furthermore, the thickness of the (b1) layer is determined by obtaining an enlarged image of the cross section using an SEM or by measurement using a laser length measuring microscope or the like. The refractive index of the layer (b1) is used as a variable to determine the refractive index that best matches the measured reflection spectrum.

[0096] In a layer containing at least one selected from the group consisting of silica and (poly)silsesquioxane, when hollow particles are included and when no hollow particles are included, the refractive index of the layer tends to be lower in the former case. Therefore, a high antireflection effect may be expected in a structure in which an antireflection film has a layer containing at least one selected from the group consisting of silica and (poly)silsesquioxane and hollow particles, a layer containing at least one selected from the group consisting of silica and (poly)silsesquioxane and no hollow particles, and an optical filter or light absorber 10 stacked in this order.

[0097] The fine particles contained in layer (b) may be solid particles. A layer containing solid particles, silsesquioxane, and silica is referred to as layer (b2) to distinguish it from the layer containing hollow particles described above. The refractive index of the solid particles is, for example, 1.25 to 2.75. When layer (b) contains solid particles, layer (b2) has a refractive index of, 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, and examples of such particles include Snowtex MP-2040 manufactured by Nissan Chemical Industries, Ltd. The refractive index of layer (b2) may be determined using a method similar to that used to determine the refractive index of layer (b1) described above.

[0098] The (b2) layer 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 (b2) layer may contain one selected from the group consisting of TiO (titanium oxide, refractive index 2.33 to 2.55), TaO (tantalum oxide, refractive index 2.16), NbO (niobium oxide, refractive index 2.33), and SiN (silicon nitride, refractive index 2.02), or may contain a mixture of at least two selected from this group. In particular, the (b2) layer may contain TiO particles. In this case, the average particle diameter of the TiO particles may be 2 nm to 200 nm. The content of the TiO particles in the (b2) layer is, for example, 2% to 50%. Examples of TiO particles that can be used include NS405 manufactured by Teika Corporation and TTO-51A manufactured by Ishihara Sangyo Kaisha, Ltd. The average particle size of the fine particles contained in the (b2) layer may be determined by the same method as the average particle size of the fine particles contained in the (b1) layer. The content of the fine particles contained in the (b2) layer is, for example, 5% to 95% by mass. The content of the fine particles in the (b2) layer is, for example, 30% to 99% by volume. The content of the fine particles in the (b2) layer may be determined by the same method as the volume percentage of the fine particles contained in the (b1) layer.

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

[0100] The layers (a), (b1), and (b2) contain a silicon compound as a binder or matrix, similar to a light absorber containing a silicon compound. Therefore, alkoxy groups and their hydrolyzed silanol groups are present between the layers and react with hydroxyl groups, etc., which is expected to improve adhesion and contribute to improved peel resistance. The layers (a), (b1), and (b2) are further classified as, for example, low-refractive-index layers, medium-refractive-index layers, and high-refractive-index layers. In this case, the low-refractive-index layer is layer (b1) containing at least one selected from the group consisting of silica and (poly)silsesquioxane and hollow particles. The medium-refractive-index layer is layer (a) containing at least one selected from the group consisting of silica and (poly)silsesquioxane but not hollow particles. The high-refractive-index layer is layer (b2) 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 TiO particles. For example, the anti-reflection coating may be configured taking into consideration the combination of these layers, the thickness of the layers, the number of layers, the repetitive pattern in the combination of layers, etc. By comparing the refractive indexes of the layers, the condition that the refractive index of layer (b1) < the refractive index of layer (a) < the refractive index of layer (b2) is satisfied.

[0101] The antireflection coating may be configured by laminating a layer (b1) containing silica, (poly)silsesquioxane, and hollow particles with a layer (b2) containing silica, (poly)silsesquioxane, and solid particles with a relatively high refractive index, such as TiO particles. The refractive index of layer (b2) is higher than that of layer (b1). Such a configuration of an antireflection coating by laminating layers with substantially different refractive indices is highly effective in terms of widening the antireflection band and reducing reflectance.

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

[0103] The sol precursor thus prepared is applied to a substrate requiring an anti-reflection effect, in this case, the surface of a light absorber or optical filter, by adjusting the coating conditions and coating amount to achieve a predetermined thickness. Examples of coating methods include spin coating, dipping, rolling, dispensing, spray coating, and bar coating, but other methods may also be used. After application of the sol precursor, reactions such as hydrolysis of the alkoxysilane and polymerization of the hydrolyzate proceed, resulting in solidification of the sol precursor. Heating may also be performed, if desired, to promote the reaction or remove by-products. In addition to the reaction in the sol, a solidification process may also be included in which a gel is formed by evaporation or drying of the solvent or liquid components.

[0104] The layer (c) can be formed as a layer made of a dielectric or metal oxide by physical vapor deposition such as vacuum deposition including ion-assisted deposition (IAD), sputtering, or ion plating. The material of the layer (c) is not limited to a specific material. The layer (c) can be formed of, for example, SiO2, TiO2, Ta2O3, SnO2, In2O3, Nb2O5, Si3N4, TiN xand MgF2. The layer (c) may be composed of a material in which these compounds are mixed at a predetermined ratio, and the refractive index of the layer (c) may be adjusted by adjusting the mixing ratio of the material in which different compounds are mixed.

[0105] The layer (c) may be a single layer made of the same material, or may be a multilayer formed by stacking two or more layers containing different materials selected from the above compounds and mixtures of the above compounds. When the layer (c) is a multilayer, the antireflection coating may be formed by alternately stacking layers made of relatively high refractive index materials such as TiO , Ta O , and Nb O or mixtures thereof with layers made of relatively low refractive index materials such as SiO and MgF or mixtures thereof, while adjusting the thickness and number of repetitions. In this case, too, stacking layers with substantially different refractive indexes to form an antireflection coating is expected to be highly effective in terms of widening the antireflection band or reducing reflectance, and is advantageous for users of optical filters or light absorbers.

[0106] In the optical filter 1d in which the antireflection films 31a and 32a are provided on both sides of the light absorber 10, the average value T2 of the transmittance in the wavelength range of 400 nm to 600 nm A 460-600 is preferably 90% or more, and more preferably 94% or more. In this case, almost no light in the visible light range is attenuated and passes through the optical filter 1d. Therefore, the optical filter 1d has extremely advantageous properties as an optical filter used in an imaging device.

[0107] In addition, in the optical filter 1d in which the antireflection films 31a and 32a are provided on both sides of the light absorber 10, the OD value, which is the optical density at wavelength λ, divided by the thickness of the light absorber (the thickness of the optical filter minus the thickness of the antireflection films) is η 2-λ [μm -1 ], 0.009≦η 2-380 and 0.008≦η 2-750 It is desirable that 0.012≦η 2-380 and 0.010≦η 2-750It is even more desirable that:

[0108] In the optical filter 1d in which antireflection films 31a and 32a are provided on both sides of the light absorber 10, it is desirable that the optical filter 1d has a haze (cloudiness) of less than 0.2%, similar to an optical filter in which no antireflection film is provided, it is more desirable that the haze be 0.18% or less, and it is particularly desirable that the haze be 0.15% or less.

[0109] In the optical filter 1d in which the antireflection films 31a and 32a are provided on both sides of the light absorber 10, for example, 0.020≦η 2-900 and 0.013≦η 2-1100 Furthermore, the optical filter 1d may satisfy the requirement of 0.020≦η 2-800 and 0.012≦η 2-1000 may be satisfied.

[0110] The optical filter 1d preferably has a refractive index of 0.022≦η 2-900 and 0.015≦η 2-1100 and 0.025≦η 2-800 and 0.015≦η 2-1000 may be satisfied.

[0111] The optical filter 1d in which the antireflection films 31a and 32a are provided on both sides of the light absorber 10 has a reflectivity of, for example, T2 A 300-380 ≦1.5% and T A 750-1100 ≦2.0% requirement, and preferably T A 300-380 ≦1.2% and T A 750-1100 ≦1.5%, and more preferably, T A 300-380 ≦1.0% and T A 750-1100 The requirement of ≦1.0% may be met. A 300-380 is the average value of the transmittance at wavelengths of 300 nm to 380 nm, and T2 A 750-1100is the average value of the transmittance in the wavelength range of 750 nm to 1100 nm.

[0112] The optical filter 1d, in which the antireflection films 31a and 32a are provided on both sides of the light absorber 10, has a wavelength of 390 nm≦λ2, for example. 0 UV ≦450 nm requirement and 600 nm≦λ 0 IR Meets the requirement of λ≦680 nm. 0 UV is the second ultraviolet cutoff wavelength at which the transmittance is 50% in the wavelength range of 350 nm to 460 nm in the optical filter 1d, and λ 0 IR is a second infrared cutoff wavelength at which the transmittance of the optical filter 1d is 50% within the wavelength range of 600 nm to 700 nm.

[0113] An ambient light sensor may be provided that includes the light absorber 10 or an optical filter including the light absorber 10. The ambient light sensor is a device that is mounted on an apparatus and detects the brightness, hue, etc. of the surroundings of the apparatus. The ambient light sensor recognizes the attributes of the light around the apparatus, and automatically adjusts, for example, the brightness, etc. of a display device such as a display mounted on the apparatus. The ambient light sensor is also called a luminance sensor or an illuminance sensor.

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

[0115] The ambient light sensor may include an optical filter including a light absorber 10 as shown in FIG. 3A , or may include an integrated photoelectric conversion element in which the light absorber 10 and a photoelectric conversion element are integrated as shown in FIG. 3B . The photoelectric conversion element 2b shown in FIG. 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. The integrated photoelectric conversion element can be obtained, for example, by applying the above-described 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 such a photoelectric conversion element is used, there is no need to use a light absorber separate 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, by absorption in the light absorber 10, significantly improving the ease of use of the ambient light sensor as an ambient light sensor specialized for detecting light in the approximately visible light range. In addition, simplification of the supply chain for product distribution can also be expected.

[0116] In the photoelectric conversion element 2b, for example, a first electrode E1 and a photoelectric conversion layer L are stacked in this order on an electric circuit board 3. In addition, a second electrode E2, a light receiving surface 2f, and a light absorber 10 are disposed on the photoelectric conversion layer L.

[0117] An anti-reflection film or a reflection reduction film may be provided on the surface of the light absorber 10 or the optical filter including the light absorber 10 mounted on the ambient light sensor in order to reduce the reflectance and increase the transmittance of light of a predetermined wavelength.

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

[0119] For example, in an imaging device equipped with a light absorber 10 or an optical filter including the light absorber 10, some ultraviolet and infrared light is blocked by absorption, while light in the visible light range passes through the optical filter toward the image sensor. If the optical filter has the function of reflecting some light using a dielectric multilayer film or the like, some of the light reflected by the optical filter may be reflected inside the housing or on the surface of a lens system located in front of the optical filter, or some of the reflected light may project onto the aperture or its shape and reach the light receiving surface of the imaging element, resulting in phenomena that degrade contrast, such as ghosts and flares. On the other hand, with an imaging device equipped with an optical filter including the light absorber 10, such phenomena are less likely to occur, and ghosts, flares, etc. are less noticeable in the captured image.

[0120] FIG. 4A is a diagram showing an example of an imaging device. This diagram shows an outline of the imaging device, and only elements necessary for explanation are schematically depicted, with other parts or elements omitted. As shown in FIG. 4A , an imaging device 6a includes an image sensor 7, a lens system 8, and an optical filter 1a. In the imaging device 6a, the optical filter 1a is disposed, for example, between the image sensor 7 and the lens system 8 and immediately before the image sensor 7. The arrangement of the optical filter is not limited to the arrangement shown in FIG. 4A . The optical filter may be disposed on the subject side, in front of the lens system 8. In this case, the optical filter includes, for example, a light absorber 10 and a transparent dielectric substrate that supports 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 that protects the imaging device and the lens system from the outside.

[0121] FIG. 4B is a diagram showing another example of an imaging device. The imaging device 6b is configured similarly to the imaging device 6a, except for portions not specifically described. As shown in FIG. 4B , in the imaging device 6b, a light absorber 10 is disposed on the surface of some of the lenses 8a included in the lens system 8. For example, the above-described light-absorbing composition can be applied to the surface of the lens 8a and cured, and the light absorber 10 can be disposed so as to form an interface with the lens 8a. This allows the lens system 8 to have the desired light-blocking properties without providing a light-absorbing optical filter separately from the lens system 8, thereby significantly simplifying the assembly or manufacturing of the imaging device. Lenses 8a integrally formed with such light absorbers 10, or lens systems including such lenses 8a, may be distributed. An anti-reflection or 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, making it easier to increase transmitted light in the visible light range. In the imaging device 6b, the arrangement of the light absorbers 10 is not limited to the arrangement shown in FIG. 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, the above-described 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 components contained in the light absorber 10 is expected. When the light-absorbing composition is prepared so that the refractive indexes of the light absorber 10 and the lens are approximately the same, reflection at the interface between the light absorber 10 and the lens can be significantly reduced, resulting in the advantage of eliminating the need for anti-reflection coating.

[0123] The present invention will be described in more detail with reference to examples, but 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 a copper acetate solution (1-A). Next, 40 g of THF was added to 0.610 g of phenylphosphonic acid and stirred for 30 minutes to obtain a solution (1-B). 40 g of THF was added to 3.660 g of 4-bromophenylphosphonic acid and stirred for 30 minutes to obtain a solution (1-C). 40 g of THF was added to 0.758 g of n-butylphosphonic acid and stirred for 30 minutes to obtain a solution (1-D). The (1-A) solution was mixed with the (1-B), (1-C), and (1-D) solutions, and then 4.00 g of n-hexadecyltrimethoxysilane, a trifunctional alkoxysilane, and 2.78 g of tetraethoxysilane, a tetrafunctional alkoxysilane, were added and stirred for another 1 minute to obtain the (1-E) solution. Next, 40 g of toluene was added to the (1-E) solution, and the mixture was stirred at room temperature for 1 minute to obtain the (1-F) solution. The (1-F) solution was placed in a flask and heated in an oil bath (manufactured by Tokyo Rikakikai Co., Ltd., model: OSB-2100), while being treated with a rotary evaporator (manufactured by Tokyo Rikakikai Co., Ltd., model: N-1110SF), the reaction proceeded, and the THF was removed. The set temperature of the oil bath was adjusted to 85°C. The treated solution was then removed from the flask. In this way, a light-absorbing composition (1-G) was obtained, which was a liquid light-absorbing composition according to Example 1, comprising a light-absorbing compound containing phosphonic acid and a copper component, and a silicon-containing compound containing an n-hexadecyl group. The amount (content) of each compound added in the preparation of the light-absorbing composition according to Example 1 is shown in Table 1. Table 1 also shows the amount (content) of each compound added in the preparation of the light-absorbing compositions according to the other Examples and Comparative Examples.

[0125] A coating film of the light-absorbing composition (1-G) was formed on one main surface of a substrate, a borosilicate glass substrate (manufactured by SCHOTT, product name: D263 T eco) having dimensions of 76 mm x 76 mm x 0.21 mm, using a dispenser. The resulting coating film was thoroughly dried at room temperature, then placed in an oven and heated at a temperature ranging from room temperature to 85°C for approximately 6 hours to sufficiently promote the reaction of the alkoxysilane and volatilize the organic solvent contained in the light-absorbing composition (1-G). The coating film was then placed in an environment of a temperature of 85°C and a relative humidity of 85% for an additional 8 hours to perform post-cure and complete the reaction. In this way, the light absorber according to Example 1 was obtained. In addition, an optical filter according to Example 1 in which the light absorber according to Example 1 was disposed on a substrate was obtained.

[0126] The haze of the light absorber according to Example 1 was measured in accordance with Japanese Industrial Standard JIS K 7136:2000 using a haze meter HM-65L2 manufactured by Murakami Color Research Laboratory Co., Ltd. As shown in Table 2, the haze value of the light absorber according to Example 1 was 0.19%. Table 2 also shows the haze values ​​of the light absorbers according to the other Examples and Comparative Examples, except for cases where no measurement was performed.

[0127] Using a laser displacement meter LK-H008 manufactured by Keyence Corporation, the thickness of the light absorber according to Example 1 was measured. 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 the other Examples and Comparative Examples, except for cases where measurement was not performed.

[0128] The transmission spectrum of the light absorber according to Example 1 at an incident angle of 0° was measured using a UV-Visible-Near-Infrared Spectrophotometer V-770 equipped with a transmitted light measurement attachment manufactured by JASCO Corporation. The measurement of the transmission spectrum was carried out by adjusting the temperature of the environment surrounding the optical filter to 22 to 25°C, unless otherwise specified. In this measurement, the measurement attachment was replaced with a reflected light measurement attachment, and the reflection spectrum of the light absorber according to Example 1 at an incident angle of 5° was measured. The measurement of the reflection spectrum was carried out by adjusting the temperature of the environment surrounding the optical filter to 22 to 25°C, unless otherwise specified. FIG. 5A shows the transmission spectrum of the light absorber according to Example 1. FIG. 5B shows the reflection spectrum of the light absorber according to Example 1. Table 2 shows characteristic values ​​related to the optical conditions of the light absorber at an incident angle of 0°. Table 3 shows η, which is calculated by dividing the optical density at a specific wavelength by the thickness of the light absorber. λ Tables 2 and 3 show the characteristic values ​​relating to the transmittance or reflectance of the light absorbers according to other examples and comparative examples, as well as the values ​​of η λ Indicates the value of

[0129] Examples 2 to 14 Light absorbers according to Examples 2 to 12 were produced by the same method and conditions as in Example 1, except that the necessary compounds and the amounts added thereof were changed as shown in Table 1A. Furthermore, light absorbers according to Examples 13 and 14 were produced by the same method and conditions as in Example 1, except that the necessary compounds and the amounts added thereof were changed as shown in Table 1B. The results of measuring or calculating the characteristic values ​​of each light absorber are shown in Tables 2 and 3. The transmission spectrum and reflection spectrum of the light absorber according to Example 2 are shown in FIGS. 6A and 6B, respectively. The transmission spectrum and reflection spectrum of the light absorber according to Example 3 are shown in FIGS. 7A and 7B, respectively. The transmission spectrum of the light absorber according to Example 8 is shown in FIG. 8. The transmission spectrum of the light absorber according to Example 13 is shown in FIG. 9. The transmission spectrum of the light absorber according to Example 14 is shown in FIG. 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 substrate (manufactured by SCHOTT, product name: D263 T eco) measuring 76 mm x 76 mm x 0.21 mm. The glass substrate was then left at room temperature for 24 hours to dry the coating of the fluorine treatment agent. The glass surface was then lightly wiped with a dust-free cloth impregnated with Novec 7100 to remove excess fluorine treatment agent. A fluorine-treated substrate was thus produced.

[0131] A light-absorbing composition according to Example 15 was prepared by the same method and conditions as in Example 1, except that the necessary compounds and the amounts added were changed as shown in Table 1. A 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 base material, and a light absorber was prepared on a fluorine-treated substrate in the same manner as in Example 1. Next, this light absorber was peeled from 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 respective 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 Plysurf A208N (Dai-ichi Kogyo Seiyaku Co., Ltd.), a phosphate ester compound, 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 solution (16-C), followed by stirring at room temperature for 1 minute to obtain solution (16-D). This (16-D) solution was placed in a flask and heated in an oil bath (Tokyo Rikakikai Co., Ltd., model: OSB-2100), while undergoing a solvent removal treatment using a rotary evaporator (Tokyo Rikakikai Co., Ltd., model: N-1110SF). The set temperature of the oil bath was adjusted to 105°C. Thereafter, the solution after solvent removal treatment was removed from the flask. In this way, a liquid composition (16-E) was obtained in which a light-absorbing compound containing a phosphonic acid and a copper component was dispersed.

[0134] Silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KR-300) 7.54 g, catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., product name: CAT-AC) 0.18 g, methyltriethoxysilane as a trifunctional alkoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KBE-13) 9.74 g, tetraethoxysilane as a tetrafunctional alkoxysilane (manufactured by Kishida Chemical Co., Ltd. special grade) 5.68 g, dimethyldiethoxysilane (DMDES) as a difunctional alkoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KBE-22) 5.70 g was mixed and stirred for 30 minutes to obtain a liquid curable resin (16-F). Furthermore, the above liquid composition (16-E) and the liquid curable resin (16-F) were mixed and stirred for 30 minutes, and then a light-absorbing film composition (16-G) was prepared.

[0135] A coating film was formed by applying the light-absorbing film composition (16-G) using a dispenser to an 80 mm x 80 mm area in the center of a fluorine-treated substrate prepared in the same manner as in Example 15. The resulting coating film was thoroughly dried at room temperature and then placed in an oven and heated sufficiently within a range of room temperature to 85°C to fully promote the reaction of the alkoxysilane and volatilize the organic solvent contained in the light-absorbing film composition (16-G). The film was then post-cured for an additional 24 hours in an environment at a temperature of 85°C and a relative humidity of 85%, completing the reaction and producing a light absorber on the fluorine-treated substrate. Next, the light absorber was peeled from the fluorine-treated substrate to obtain a film-like light-absorbing substrate (16-H). Figure 11A shows the transmission spectrum of the light-absorbing substrate (16-H). In addition, Tables 2 to 4 show the characteristic values ​​and thickness of the film-like light-absorbing substrate (16-H) that can be seen from this transmission spectrum.

[0136] A light-absorbing composition according to Example 16 was prepared by the same method and conditions as in Example 1, except that the necessary compounds and their addition amounts were changed as shown in Table 1. An optical filter according to Example 16 having two light-absorbing layers was prepared by the same method and conditions as in Example 1, except that the light-absorbing composition according to Example 16 was used instead of Example 1, and a light-absorbing substrate (16-H) was used as the substrate. FIG. 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 each characteristic value of the optical filter according to Example 16.

[0137] <Comparative Examples 1 to 3> Light absorbers according to Comparative Examples 1 to 3 were produced by the same method and conditions as in Example 1, except that the necessary compounds and the amounts added thereof were changed as shown in Table 1. Fig. 12 shows the transmission spectrum of the optical filter according to Comparative Example 3. Tables 2 and 3 show the measurement results and calculation results of each characteristic value that could be measured or calculated for the light absorbers according to Comparative Examples 1 to 3.

[0138] The light-absorbing composition of Comparative Example 1 exhibited significant turbidity, making it impossible to produce a transparent optical filter. It is presumed that the aggregation-inhibiting effect of the produced copper phosphonate compound was insufficient in Comparative Example 1 because the number of carbon atoms in the alkyl group directly bonded to the silicon atom in the added trifunctional alkoxysilane was as low as 6. Therefore, the amount of trifunctional alkoxysilane added was increased in Comparative Example 2, but significant turbidity still occurred. An optical filter could be produced in Comparative Example 3, in which the amount of trifunctional silane added was further increased. However, as shown in FIG. 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 of Comparative Example 3 was also very high at 12.96, making it impossible to produce an optical filter with good properties. These results suggest that when the number of carbon atoms in the alkyl group of the trifunctional linear alkylsilane is less than 10, a sufficient aggregation-inhibiting effect of copper phosphonate cannot be obtained, making it difficult to produce an optical filter with good optical properties.

[0139] Example 17 (Preparation of liquid precursor for forming antireflective film) 0.87 g of tetraethoxysilane (TEOS), which is a type of tetrafunctional silane, 1.33 g of methyltriethoxysilane (MTES), which is 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 and Chemicals, product name: Sururia 4110, silica solid content: approximately 25 wt %), and 27.3 g of ethanol were mixed and reacted at 30°C for 1 hour and then at 35°C for 2 hours to prepare liquid precursor A for forming an antireflective film (hereinafter referred to as antireflective film-forming liquid composition A).

[0140] (Preparation of Optical Filter with Antireflection Film) Antireflection film-forming liquid composition A was applied to one side of an optical filter prepared under the same conditions and method as in Example 15, adjusting the coating amount and coating conditions so that the film thickness after drying and curing would be 120 nm. A spin coater was used for coating, and the rotation speed and rotation time were also adjusted. The optical filter with antireflection film-forming liquid composition A applied to one side was left to stand for about 1 minute for initial drying. Furthermore, antireflection film-forming liquid composition A was applied to the other side of the optical filter under the same conditions and method. The optical filter with the initially dried antireflection film-forming composition A applied to both sides was then left to stand in an oven heated to an internal temperature of 85°C for 1 hour to react and solidify the composition, thereby preparing the optical filter of Example 17. This optical filter had antireflection films on both sides. The transmission spectrum of the optical filter of Example 17 is shown in FIG. 13. Table 5 shows the characteristic values ​​and calculated values ​​based on the transmission spectrum, and Table 6 shows the values ​​obtained by dividing the optical density OD value at each wavelength λ by the thickness of the light absorber.

[0141] Example 18 Preparation of Liquid Precursor for Forming Antireflective Film 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. In this manner, composition B for forming an antireflective film was prepared.

[0142] (Preparation of Optical Filter with Antireflection Film) Antireflection film-forming liquid composition B was applied to one side of an optical filter prepared under the same conditions and method as in Example 15, with the coating amount and coating conditions adjusted so that the film thickness after drying and curing would be 250 nm. A spin coater was used for coating, and the rotation speed and rotation time were also adjusted. The optical filter with antireflection film-forming liquid composition B applied to one side was left to stand for about 1 minute for initial drying. Furthermore, antireflection film-forming liquid composition B was applied to the other side of the optical filter under the same conditions and method. The optical filter with the antireflection film-forming composition B applied to both sides thus initially dried was left to stand in an oven heated to an internal temperature of 85°C for 1 hour to react and solidify the composition. Next, for the optical filter having layers of solidified reflection film-forming composition B on both sides, antireflection film-forming liquid composition A was applied to one side of the optical filter, with the coating amount and coating conditions adjusted so that the film thickness after drying and curing would be 90 nm. A spin coater was used for coating, and the rotation speed and rotation time were also adjusted. The optical filter coated with the anti-reflection coating-forming liquid composition A on one side was left standing for about 1 minute for initial drying. Furthermore, the anti-reflection coating-forming liquid composition A was coated on the other side of the optical filter under the same conditions and method. The optical filter coated with the anti-reflection coating-forming composition A on both sides, which had been initially dried in this manner, was left standing for 1 hour in an oven heated to an internal temperature of 85°C to react and solidify the composition, thereby producing the optical filter of Example 18. This optical filter had anti-reflection coatings on both sides. The transmission spectrum of the optical filter of Example 18 is shown in Figure 14. The characteristic values ​​and calculated values ​​based on the transmission spectrum are shown in Table 5. Furthermore, the optical density OD value at each wavelength λ divided by the thickness of the light absorber is shown in Table 6.

[0143]

[0144]

[0145]

[0146]

[0147]

[0148]

[0149]

Claims

1. 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 a light-absorbing compound. A light-absorbing composition.

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

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

4. The light-absorbing composition according to any one of claims 1 to 3, wherein a light absorber which is a solidified product of the light-absorbing composition satisfies 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 as η λ [μm -1 ], 0.009 ≦ η 380 and 0.008 ≦ η 750 (ii)When the average value of the transmittance in the wavelength range of 460 nm to 600 nm is represented by T A 460-600 then 80% ≤ T A 460-600

5. The light-absorbing composition according to any one of claims 1 to 3, wherein the light-absorbing composition does not contain a phosphate ester.

6. A light absorber, Average value T A 460-600 is 80% or more, The average value T A 460-600 is the average value of the transmittance within the wavelength range of 460 nm to 600 nm of the transmission spectrum obtained by irradiating the light absorber with light at an incident angle of 0°, The value obtained by dividing the optical density OD at the wavelength λ of the light absorber by the thickness of the light absorber is η λ [μm -1 , when expressed as such, 0.009 ≦ η 380 and 0.008 ≦ η 750 satisfies the requirements of The 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 average value T A 750-1100 is T A 300-380 ≦ 1.5% and T A 750-1100 satisfies the requirement of ≦ 2.0%, The average value T A 300-380 is the average value of the transmittance within the wavelength range of 300 nm to 380 nm of the transmission spectrum, The average value T A 750-1100 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 the light absorber according to claim 6 or 7.

10. The optical filter according to claim 9, comprising the light absorber and an antireflection film provided on the surface of the light absorber.

11. The optical filter according to claim 10, wherein the antireflection film includes one or more layers selected from the group consisting of the following (a), (b1), (b2), and (c). (a) A layer containing silsesquioxane and silica (b1) A layer containing silsesquioxane, silica, and hollow particles (b2) A layer containing silsesquioxane, silica, and solid particles

12. (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 at least one material selected from the group consisting of MgF 2 and a layer containing The optical filter according to claim 11, wherein the layer of (b1) contains hollow particles having a refractive index of 1.02 to 1.

50.

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

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

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

50.

16. The optical filter according to claim 11, wherein the layer of (b2) contains solid particles having a refractive index of 1.25 to 2.

75.

17. ​ An ambient light sensor comprising the light absorber according to claim 6 or 7.

18. An imaging device comprising the light absorber according to claim 6 or 7.

19. 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; Removing a part of the solvent from the light-absorbing compound dispersion, and A method for producing a light-absorbing composition.

20. The 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 cured product is η λ [μm -1 , when expressed as, 0.009 ≤ η 380 and 0.008 ≤ η 750 (ii) When the average value of the transmittance in the wavelength range of 460 nm to 600 nm is represented as T A 460-600 then 80% ≤ T A 460-600

21. 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 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, A method for producing a light absorber.

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

23. A light absorber and An antireflection film provided on the surface of the light absorber, and An optical filter satisfying the following conditions (I) and (II). Let η be the value obtained by dividing the optical density OD at wavelength λ by the thickness of the light absorber. 2-λ [μm -1 , when expressed as such, 0.009 ≤ η 2-380 and 0.008 ≤ η 2-750 (II) When the average value of the transmittance in the wavelength range of 460 nm to 600 nm is represented by T 2 A 460-600 then 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 condition is satisfied.

25. Let the average value of the transmittance in the wavelength range of 300 nm to 380 nm be T 2 A 300-380 and let the average value of the transmittance in the wavelength range of 750 nm to 1100 nm be T 2 A 750-1100 When this is the case, T 2 A 300-380 ≤ 1.5% and T 2 A 750-1100 ≤ 2.0%, and The second ultraviolet cut-off wavelength at which the transmittance becomes 50% within the range of wavelengths from 350 nm to 460 nm is λ 2 0 UV and the second infrared cut-off wavelength at which the transmittance becomes 50% within the range of wavelengths from 600 nm to 700 nm is 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 claim 23 or 24, wherein the antireflection film includes a layer containing silsesquioxane and silica.