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

Abstract

This light-absorbing composition includes a silicon-containing compound α and a light-absorbing compound. The silicon-containing compound α includes at least one selected from the group consisting of a first alkoxysilane represented by formula (1), a hydrolysate of the first alkoxysilane, and a polymer of the hydrolysate of the first alkoxysilane. In formula (1), n is 1, 2, or 3, R11is a group including at least a carbon atom (C) and a hydrogen atom (H), and at least one of R11is a group α-1 having 10 or more carbon atoms. R12is a group including at least a carbon atom (C) and a hydrogen atom (H), and may be the same as R11 and may be different from R11.　Formula (1): R11 4-nSi(OR12)n

Description

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

[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 of approximately 380 nm to 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 known technique is to place an optical filter 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 optical properties and moisture resistance. Therefore, the present invention provides a light-absorbing compound that is advantageous from the viewpoints of optical properties and moisture resistance. The present invention also provides a light-absorbing material that is advantageous from the viewpoints of optical properties and moisture resistance.

[0010] The present invention provides a light-absorbing composition comprising at least one selected from the group consisting of a primary alkoxysilane represented by the following formula (1), a hydrolysate of the primary alkoxysilane, and a polymer of the hydrolysate of the primary alkoxysilane, and a light-absorbing compound. 11 4-n Si(OR 12 ) n Formula (1): In formula (1), n ​​is 1, 2, or 3; 11is 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 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.

[0011] The present invention also provides a light absorber comprising: silica; at least one selected from the group consisting of polyorganosilsesquioxanes and polydiorganosiloxanes, each containing a group having 10 or more carbon atoms; and a light absorbing compound containing a phosphonic acid and a copper component.

[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, 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 a primary alkoxysilane represented by the following formula (1) or a hydrolysate of the primary alkoxysilane; and removing a portion of the solvent from the light-absorbing compound dispersion. 11 4-n Si(OR 12 ) n 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 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.

[0016] The above light-absorbing composition and light-absorbing material are advantageous in terms of optical properties and moisture resistance.

[0017] 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 the 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. 5 is a graph showing the transmission spectrum of a light absorber according to Example 1. FIG. 6 is a graph showing the transmission spectrum of a light absorber according to Example 2. FIG. 7 is a graph showing the transmission spectrum of a light absorber according to Example 3. FIG. 8 is a graph showing the transmission spectrum of a light absorber according to Example 4. FIG. 9 is a graph showing the transmission spectrum of a light absorber according to Example 7. FIG. 10 is a graph showing the transmission spectrum of a light absorber according to Example 8. FIG. 11 is a graph showing the transmission spectrum of a light absorber according to Example 16. Fig. 12 is a graph showing the transmission spectrum of a light absorber according to Example 24. Fig. 13 is a graph showing the transmission spectrum of a light absorber according to Comparative Example 3. Fig. 14 is a graph showing the transmission spectrum of a light absorber according to Comparative Example 6. Fig. 15 is a graph showing the transmission spectrum of a light absorber according to Example 2 before and after a moisture resistance test. Fig. 16 is a graph showing the transmission spectrum of a light absorber according to Example 3 before and after a moisture resistance test. Fig. 17 is a graph showing the transmission spectrum of a light absorber according to Example 5 before and after a moisture resistance test. Fig. 18 is a graph showing the transmission spectrum of a light absorber according to Example 6 before and after a moisture resistance test. Fig. 19 is a graph showing the transmission spectrum of a light absorber according to Example 16 before and after a moisture resistance test. Fig. 20 is a graph showing the transmission spectrum of a light absorber according to Example 19 before and after a moisture resistance test. Fig. 21 is a graph showing the transmission spectrum of a light absorber according to Example 21 before and after a moisture resistance test.

[0018] With the global spread of information terminals such as smartphones equipped with camera modules, there is a growing demand for optical filters to be installed in cameras or ambient light sensors. Although the optical filter described in Patent Document 1 has a transmittance of 5% or less at wavelengths of 750 nm to 1080 nm, its light absorption characteristics in this wavelength range are far from sufficient. In other words, it is understood that it is difficult to achieve sufficient light absorption performance in an optical filter having a light absorption layer containing copper phosphonate and an organic dye, even when the organic dye is used in combination.

[0019] The optical filter described in Patent Document 2 is promising because it does not contain a phosphate ester, but it is difficult to say that it has sufficient optical properties. In addition, the absence of a phosphate ester may cause some of the copper phosphonate to aggregate, reducing transmittance in the visible range.

[0020] 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 the precursor of the UV-IR absorbing layer. The UV-IR absorbing layer described in Patent Document 3 has a haze value of at most 0.2%. In light-absorbing optical filters, it is sometimes required to achieve a haze of, for example, 0.5% or less.

[0021] 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 transmittance close to the human luminosity curve and low haze, as well as moisture resistance. In addition, they have completed a novel light absorber that is advantageous from the viewpoint of realizing desired optical properties such as transmittance close to the human luminosity curve and low haze, as well as moisture resistance.

[0022] Hereinafter, embodiments of the present invention will be described. Note that the following description relates to examples of the present invention, and the present invention is not limited to the following embodiments. In this specification, unless otherwise specified, "silicon" means silicon (Si) and "silicone" means resin. When a numerical range is expressed using the numerical values ​​X and Y, such as X to Y, the numerical range means the range from X to Y (a range equal to or greater than X and equal to or less than Y), including the numerical values ​​X and Y, unless otherwise specified. Furthermore, moisture resistance refers to the characteristic that even when exposed to moisture in the atmosphere, the deterioration of performance due to chemical reactions caused by the exposure is within an acceptable range, and includes moisture resistance in high-temperature environments up to 85°C (also referred to as high-temperature and high-humidity resistance).

[0023] The light-absorbing composition contains a silicon-containing compound α and a light-absorbing compound. The silicon-containing compound α contains at least one selected from the group consisting of a primary alkoxysilane represented by the following formula (1), a hydrolyzate of the primary alkoxysilane, and a polymer of the hydrolyzate of the primary alkoxysilane. In formula (1), n ​​is 1, 2, or 3, and R 11 is a group containing at least a carbon atom (C) and a hydrogen atom (H), 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)

[0024] An alkoxysilane hydrolysate is a silicon compound having a silanol group (—Si—OH) generated by the hydrolysis of an alkoxysilane. A polymer of an alkoxysilane hydrolysate is a compound containing a siloxane bond (—O—Si—O—) resulting from condensation polymerization of a portion of the hydrolysate. It is believed that the presence of the silicon-containing compound α makes the group α-1 more likely to become a steric hindrance during the aggregation of the light-absorbing compound. Therefore, 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. In addition, the inclusion of the silicon-containing compound α in the light-absorbing composition makes it less likely that the optical properties of the light absorber formed from the light-absorbing composition will fluctuate even when placed in a high-temperature, high-humidity environment for an extended period of time.

[0025] 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 component 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 Cu y 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 anions 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. Furthermore, from the viewpoint of obtaining a highly pure light-absorbing compound, it is preferable that the content of such anions of the raw material for the copper component and its components be as small as possible. 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 are 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030]

[0031] 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.

[0032] 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.

[0033]

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] The light-absorbing composition may contain at least one silicon-containing compound β selected from the group consisting of secondary alkoxysilanes, hydrolysates of secondary alkoxysilanes, and polymers of hydrolysates of secondary alkoxysilanes, represented by the following formula (2): In formula (2), m is an integer of 3 or 4, and R 21 and R 22 may be the same or different, and R 21 and R 22 Each of R is a group containing at least a carbon atom (C) and a hydrogen atom (H). 21 and R 22may each be an alkyl group. 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 β 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 the hydrolyzate of an alkoxysilane. R 21 4-m Si(OR 22 ) m Formula (2)

[0039] The inclusion of the silicon-containing compound β 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 light-absorbing composition so that the hydrolysis reaction and condensation polymerization reaction of the alkoxysilane occur sufficiently. This facilitates the formation of a siloxane bond 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 excellent 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 21 and R 22 may be a hydrocarbon group having 1 to 8 carbon atoms, or may be a group containing an aryl group. Furthermore, in formula (2), the inclusion of a trifunctional alkoxysilane in which m=3 in addition to a tetrafunctional alkoxysilane in which m=4 can impart flexibility to the light absorber formed by the light-absorbing composition.

[0040] 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 has been substituted with a halogen atom. In this case, the alkyl group and the substituted alkyl group may or may not have a branched carbon chain.

[0041] 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. The group α-1 may have a reactive functional group such as a vinyl group, an epoxy group, a carbonyl group, an ester group, a nitrile group, or a hydroxy group.

[0042] 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.

[0043] 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.

[0044] 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, a trifunctional alkoxysilane, or a hydrolysate thereof, represented by formula (2).

[0045] 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.

[0046] 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 molar ratio r of silicon atoms contained in the silicon-containing compound α to the copper component is CS1 is, for example, 0.30 to 4.00. CS1When the molar ratio r is 0.30 or more, aggregates of the light-absorbing compound are less likely to occur in the light-absorbing composition, and the light absorber formed by the light-absorbing composition is more likely to have desired optical properties. CS1 When the ratio r is 4.00 or less, it is easy to reduce the thickness of a light absorber having desired optical properties, which is easy to contribute to reducing the height of a product including the light absorber. CS1 is preferably 0.35 to 3.00, more preferably 0.36 to 2.20. In this specification, the molar ratio of B to A refers to the ratio of the molar content of B to the molar content of A.

[0047] 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.

[0048] 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 α-1 group 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.

[0049] 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.

[0050] When the light-absorbing compound contains a phosphonic acid component and a copper component, the molar ratio r of the phosphonic acid component to the copper component is CP is not limited to a specific value. CP is, for example, 0.80 to 1.20. CP When the molar ratio r is 0.80 or more, particulate precipitates are less likely to occur in the light-absorbing composition, and the haze of the light-absorbing material formed from the light-absorbing composition is likely to be low. Therefore, the light-absorbing material is more likely to have desired optical properties. CP When the molar ratio r is 1.20 or less, the light absorber is likely to have the desired heat resistance and moisture resistance. For example, even if the light absorber is exposed to an environment at a temperature of 85° C. and a relative humidity of 85% for 1000 hours or longer, the light absorber is unlikely to become cloudy. CP is preferably 0.90 to 1.18, and more preferably 0.93 to 1.16.

[0051] When the light-absorbing compound contains a phosphonic acid component and a copper component, the molar ratio r of silicon atoms contained in the silicon-containing compound α to the phosphonic acid component is PS1 is not limited to a specific value. PS1 is, for example, 0.10 to 3.00. PS1When the molar ratio r is 3.00 or less, particulate precipitates are less likely to occur in the light-absorbing composition, and the haze of the light-absorbing material formed from the light-absorbing composition is likely to be low. Therefore, the light-absorbing material is more likely to have desired optical properties. PS1 When the molar ratio r is 0.10 or more, the light-absorbing compound is easily dispersed in a desired state in the light-absorbing composition, and the haze is easily reduced. Therefore, the light-absorbing body formed from the light-absorbing composition is more likely to have desired optical properties. PS1 is preferably 0.25 to 2.50, more preferably 0.33 to 2.00, and may be 0.40 to 3.00.

[0052] The light-absorbing composition may contain, for example, the silicon-containing compound α, the amino-group-containing silicon compound γ, and a light-absorbing compound. The amino-group-containing silicon compound γ is at least one selected from the group consisting of tertiary alkoxysilanes, hydrolysates of tertiary alkoxysilanes, and polymers of hydrolysates of tertiary alkoxysilanes, represented by the following formula (3): In formula (3), p is 1, 2, or 3; R 31 is a group containing at least a carbon atom (C), a hydrogen atom (H), and an amino group (-NH2). The hydrogen atom (H) in this amino group may be substituted with a halogen atom, an alkyl group, or an aryl group. 31 R may be an alkyl group or aryl group partially substituted with the above amino group. 32 is a group containing at least a carbon atom (C) and a hydrogen atom (H). 32 may be an alkyl group. The tertiary alkoxysilane represented by formula (3) may be referred to as an aminosilane. In this case, the molar ratio r CP Even if the upper limit of the desired range of R is increased, particulate precipitates are less likely to occur in the light-absorbing composition, and the haze of the light-absorbing material formed from the light-absorbing composition tends to be low. 31 4-p Si(OR 32 ) p Formula (3)

[0053] In the synthesis of a light-absorbing compound containing a phosphonic acid component and a copper component, for example, substitution of a counter anion such as acetate ion or an acetate component coordinated or bonded to copper with the phosphonic acid component proceeds. CP It is presumed that when the molar ratio r is high, the amount of synthesis of the light-absorbing compound containing the phosphonic acid component and the copper component increases. This increases the elimination of acetate ions and acetic acid components, etc., and the acetate ions and acetic acid components, etc., that are unnecessary for the light-absorbing composition, can be effectively removed. In the synthesis process of the light-absorbing compound, there may be problems with the synthesis conditions, such as a non-uniform state in the reaction solution, temperature imbalance, or a rapid reaction of each component. In such cases, too, the molar ratio r CP When the value is high, it is easy to obtain a good light-absorbing compound, and it is easy to prepare a desired light absorber and optical filter.

[0054] When the light-absorbing composition contains the amino group-containing silicon compound γ, the molar ratio r CP is, for example, 0.80 to 1.40, preferably 0.90 to 1.40, and more preferably 0.93 to 1.38. When the light-absorbing composition does not contain the amino group-containing silicon compound γ, the molar ratio r CP On the other hand, when the light-absorbing composition contains an amino group-containing silicon compound γ, the molar ratio r CP The upper limit of the molar ratio r CP However, even if the β-dispersion constant is in the range of 1.20 to 1.40 (but excluding 1.20), or even in the range of 1.20 to 1.38 (but excluding 1.20), a light absorber having the required performance, and further a light absorbing composition as a precursor thereof, can be prepared.

[0055] The amino group-containing silicon compound γ is not limited to a specific compound, as long as it is at least one selected from the group consisting of tertiary alkoxysilanes represented by formula (3), hydrolysates of tertiary alkoxysilanes, and polymers of hydrolysates of tertiary alkoxysilanes. Examples of the amino group-containing silicon compound γ include 3-aminopropyltriethoxysilane (3APTES), 3-aminopropyltrimethoxysilane (3APTMS), N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and 3-(N-phenyl)aminopropyltrimethoxysilane.

[0056] When the light-absorbing compound contains a phosphonic acid component and a copper component, and the light-absorbing composition contains a silicon-containing compound α and an amino group-containing silicon compound γ, the molar ratio r CS3 is not limited to a specific value. CS3 is the molar ratio of silicon atoms contained in the amino group-containing silicon compound γ to the copper component. CS3 is, for example, 0.01 to 1.00. In the preparation of the light-absorbing composition, a reaction involving the amino group of the amino group-containing silicon compound γ may occur. Since components derived from the amino group-containing silicon compound γ may be contained in the matrix of the light absorber formed by the light-absorbing compound, the effects expected from the amino group-containing silicon compound γ may be exerted even if the content of the amino group-containing silicon compound γ is extremely small. For this reason, the molar ratio r CS3 The molar ratio r may be 0.01 or more. CS3 When the molar ratio r is 1.00 or less, cracks are less likely to occur when a light absorber is formed from the light absorbing compound. CS3 is preferably 0.03 to 0.30, and more preferably 0.06 to 0.26. When the amino group-containing silicon compound γ is a tertiary alkoxysilane (aminosilane), for example, the light-absorbing composition contains the tertiary alkoxysilane, and the molar ratio r CS3 The relationship between the copper component and the silicon atom contained in the tertiary alkoxysilane (aminosilane) holds true.

[0057] For example, when the light-absorbing composition contains 3APTES as the amino group-containing silicon compound γ, it is expected that 49.9 mass % of 3APTES will remain as a solid content in the light absorber when the light-absorbing compound is formed into a light absorber.For example, when the light-absorbing composition contains 3APTMS as the amino group-containing silicon compound γ, it is expected that 61.5 mass % of 3APTMS will remain as a solid content in the light absorber when the light-absorbing compound is formed into a light absorber.

[0058] The light-absorbing composition may contain, for example, a silicon-containing compound α, a silicon-containing compound β, an amino group-containing silicon compound γ, and a light-absorbing compound.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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, the silicon-containing compound β, and the amino group-containing silicon compound γ. 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 the light-absorbing compound containing a phosphonic acid and a copper component. In addition, the curable resin is preferably selected so that the light-absorbing composition can be applied to a predetermined object to form a coating film by a coating method such as spin coating, spraying, dipping, or application with a dispenser. The curable resin is preferably one that has a smooth surface formed by curing the curable resin and has a thickness of 1 mm, and the transmission spectrum of the resin is 90% or more at wavelengths of 450 nm to 800 nm. 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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 a primary alkoxysilane represented by the above formula (1) or a hydrolyzate of a primary alkoxysilane; and (III) removing a portion of the solvent from the light-absorbing compound dispersion.

[0069] 1A to 1D, a light absorber 10 can be provided. The light absorber 10 includes, for example, silica, at least one selected from the group consisting of polyorganosilsesquioxanes and polydiorganosiloxanes containing a group having 10 or more carbon atoms, and a light absorbing compound including a phosphonic acid and a copper component.

[0070] The light absorber 10 may include, for example, nitrogen atoms directly bonded to silicon atoms.

[0071] The light absorber 10 may be provided as, for example, a solidified product of the light-absorbing composition. The polyorganosilsesquioxane and polydiorganosiloxane may be derived from the silicon-containing compound α contained in the light-absorbing composition. When the light absorber 10 contains a nitrogen atom directly bonded to a silicon atom, the nitrogen atom may be derived from the amino group-containing silicon compound γ contained in the light-absorbing composition.

[0072] 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, the light absorber 10 and a substrate 20 may constitute an optical filter 1b.

[0073] 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 light onto the light absorber 10 at an incident angle of 0°. 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. The transmission spectrum of the light absorber 10 can be obtained, for example, by measuring the transmitted light when light is incident onto the light absorber 10 at an incident angle of 0° using a spectrophotometer or the like. In other words, the transmission spectrum of the light absorber 10 may be said to be the spectrum of the transmitted light when light with a wavelength of 300 nm to 1200 nm is incident onto the light absorber at an incident angle of 0°. The characteristics of the light absorber 10 regarding the transmittance and wavelength are possessed by the transmission spectrum of the light absorber 10.

[0074] 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.

[0075] The light absorber 10 has a haze of, for example, 0.50% or less. 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 0.5% or less, 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.

[0076] The light absorber 10 has a haze of preferably 0.40% or less, more preferably 0.30% or less, even more preferably 0.20% or less, particularly preferably 0.18% or less, and especially preferably 0.15% or less.

[0077] The light absorber 10 is, for example, T A 300-380 ≦1.2% 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.

[0078] The light absorber 10 is preferably T A300-380 ≦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.

[0079] In the light absorber 10, for example, 380 nm≦λ 0 UV ≦440 nm requirement is met, and 600 nm≦λ 0 IR The requirement of λ≦680 nm may be met. 0 UV is the first cutoff wavelength at which the transmittance is 50% in the wavelength range of 350 nm to 460 nm. 0 IR is a second cutoff wavelength at which the transmittance is 50% in the wavelength range of 600 nm to 700 nm. 0 UV ≦440 nm, more preferably 395 nm≦λ 0 UV ≦440 nm, more preferably 395 nm≦λ 0 UV ≦430 nm, particularly preferably 395 nm≦λ 0 UV In the light absorber 10, the requirement of 605 nm≦λ≦420 nm is preferably met. 0 IR ≦680 nm, more preferably 610 nm≦λ 0 IR The requirement of ≦660 nm is met.

[0080] The light absorber 10 contains, for example, at least one selected from the group consisting of polyorganosilsesquioxanes and polydiorganosiloxanes containing a group having 10 or more carbon atoms, and therefore is likely to have the desired heat resistance and moisture resistance. For example, the relationship between the first transmission spectrum and the second transmission spectrum regarding the heat resistance and moisture resistance of the light absorber 10 is not limited to a predetermined relationship. The first transmission spectrum is the transmission spectrum obtained when light with a wavelength of 300 nm to 1200 nm is incident on the light absorber 10 at an incident angle of 0° after a test in which the light absorber 10 is exposed to an environment at a temperature of 85°C and a relative humidity of 85% for 1000 hours. The second transmission spectrum is the transmission spectrum obtained when light with a wavelength of 300 nm to 1200 nm is incident on the light absorber 10 at an incident angle of 0° before the test. For example, the absolute value of the difference between the average transmittances in the wavelength range of 400 nm to 580 nm in the first transmission spectrum and the second transmission spectrum is not limited to a specific value. The absolute value is, for example, 3% or less.

[0081] 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 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.

[0082] The light absorber 10 is preferably R A 450-550 The light absorber 10 preferably satisfies the requirement of R A 700-1000Meets the requirement of ≦6%.

[0083] 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 350 is 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.

[0084] The above requirements regarding transmittance, haze, and reflectance may be met in an optical filter comprising the light absorber 10 .

[0085] Thickness d of the light absorber 10 L is not limited to a specific value. L is, for example, 400 μm or less, preferably 300 μm or less, and more preferably 250 μm or less.

[0086] 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.

[0087] The surface of the substrate 20 may be formed of, for example, glass, resin, or metal. The type and optical properties of the substrate 20 are not limited to a specific embodiment as long as the light absorber 10 or an optical filter including the light absorber 10 has the desired transmittance, haze, and reflectance. In addition, 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 versatility of the optical filter 1b is likely to be high. 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 placed directly on a light receiving surface or window glass. Yet another example of the substrate 20 is a display device such as a display in a mobile terminal.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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 "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 32a provided on the surface of the light absorber 10. The antireflection films 31a and 32a 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.

[0092] 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°.

[0093] 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 SCHOTT Corporation), 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.

[0094] 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.

[0095] 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.

[0096] 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, further containing fine particles. (c) A layer formed by a physical film formation method such as vacuum deposition and sputtering.

[0097] 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. However, 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 may be, 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.

[0098] The trifunctional silane is not limited to a specific silane. Examples of the trifunctional silane include methyltriethoxysilane, methyltrimethoxysilane, ethyltriethoxysilane, ethyltrimethoxysilane, propyltriethoxysilane, propyltrimethoxysilane, butyltriethoxysilane, butyltrimethoxysilane, pentyltrimethoxysilane, pentyltriethoxysilane, hexyltriethoxysilane, and hexyltrimethoxysilane, and may also be a trifunctional silane having an alkyl group directly bonded to a silicon atom (Si). The tetrafunctional silane is not limited to a specific silane. Examples of the tetrafunctional silane include tetraethoxysilane, tetramethoxysilane, tetrapropoxysilane, and tetrabutoxysilane.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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 microparticles may be determined by observing a cross section of a structure including the (b1) layer with a scanning electron microscope (SEM) at 100,000 times magnification, measuring the particle diameters of the microparticles contained within the field of view or a predetermined range (e.g., 500 nm square), and then calculating the average value. This method may be used particularly when determining the diameter of microparticles contained in a solidified or solid layer. The content of the microparticles in the (b1) layer is, for example, 5% to 95% by mass. The content of the microparticles in the (b1) layer is, for example, 30% to 99% by volume. The content of the microparticles in the (b1) layer is determined by observing a cross section of a structure including the (b1) layer with a SEM at 100,000 times magnification, and then calculating the ratio of the volume of the microparticles to the volume of the (b1) layer. Generally, the greater the proportion of hollow microparticles in the (b1) layer, the lower the refractive index of the layer tends to be. The content of the fine particles in the layer (b1) may be, for example, 75% to 99% by volume.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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 TiO2 (titanium oxide, refractive index 2.33 to 2.55), Ta2O5 (tantalum oxide, refractive index 2.16), Nb2O5 (niobium oxide, refractive index 2.33), and Si3N4 (silicon nitride, refractive index 2.02), or may contain a mixture of at least two selected from this group. In particular, the (b2) layer may contain TiO2 particles. In this case, the average particle diameter of the TiO2 particles may be 2 nm to 200 nm. The content of the TiO2 particles in the (b2) layer is, for example, 2% to 50%. Examples of TiO2 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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 the particles, including silsesquioxane and silica).

[0112] 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] The optical filter 1d in which the antireflection films 31a and 32a are provided on both sides of the light absorber 10 preferably has a haze (cloudiness) of 0.50% or less, more preferably 0.40% or less, even more preferably 0.30% or less, particularly preferably 0.20% or less, especially preferably 0.18% or less, and extremely preferably 0.15% or less, similar to an optical filter in which no antireflection film is provided.

[0117] 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 ≦2.0%, and more preferably, T A 300-380 ≦1.2% and T A 750-1100 The requirement of ≦1.5% may be met. A 300-380 is the average value of the transmittance at wavelengths of 300 nm to 380 nm, and T2 A 750-1100 is the average value of the transmittance in the wavelength range of 750 nm to 1100 nm.

[0118] 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 ≦440 nm requirement and 600 nm≦λ 0 IR Meets the requirement of λ≦680 nm. 0 UV is a third cutoff wavelength at which the transmittance of the optical filter 1d is 50% in the wavelength range of 350 nm to 460 nm, and λ 0 IR is a fourth cutoff wavelength at which the transmittance of the optical filter 1d is 50% in the wavelength range of 600 nm to 700 nm.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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 .

[0128] 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.

[0129] The present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

[0130] 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, Solution A. Next, 40 g of THF was added to 0.610 g of phenylphosphonic acid and stirred for 30 minutes to obtain Solution B. 40 g of THF was added to 3.660 g of 4-bromophenylphosphonic acid and stirred for 30 minutes to obtain Solution C. 40 g of THF was added to 0.758 g of n-butylphosphonic acid and stirred for 30 minutes to obtain Solution D. 8.69 g of n-decyltrimethoxysilane, a trifunctional alkoxysilane, and 5.56 g of tetraethoxysilane, a tetrafunctional alkoxysilane, were added to the mixture obtained by mixing Solutions B, C, and D with Solution A, and the mixture was stirred for another 1 minute to obtain Solution E. Next, 40 g of toluene was added to Solution E, and the mixture was stirred at room temperature for 1 minute to obtain Solution F. This solution F was placed in a flask and treated with a rotary evaporator (manufactured by Tokyo Rikakikai Co., Ltd., model: N-1110SF) while being heated in an oil bath (manufactured by Tokyo Rikakikai Co., Ltd., model: OSB-2100), to advance the reaction and remove the THF. The set temperature of the oil bath was adjusted to 85°C. The treated solution was then removed from the flask. In this manner, light-absorbing composition G according to Example 1, which contains phosphonic acid and a copper component, was obtained. The materials and their amounts used in preparing light-absorbing composition G according to Example 1 are shown in Tables 1 to 3. Furthermore, ratios focusing on the amounts of specific components contained in light-absorbing composition G of Example 1 are shown in Table 4.

[0131] In order to prepare a film-like light absorber by a solution casting method (solvent casting method), the surface of a glass substrate serving as a base on which a coating film of a light-absorbing composition is formed was treated with a fluorine compound. The solution casting method here refers to a method in which a light-absorbing composition is applied to a base glass substrate, reacted or dried to solidify, and then peeled off from the base to prepare a film-like light absorber. By coating the surface of the base glass substrate in advance with a fluorine-containing resin, a fluorine-treated substrate capable of exhibiting strong non-adhesive properties was obtained, and the solidified light absorber could be peeled off from the glass substrate.

[0132] 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 130 mm x 100 mm x 0.70 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 containing Novec 7100 to remove excess fluorine treatment agent. In this manner, a fluorine-treated substrate was prepared.

[0133] A coating film of the light-absorbing composition was formed on the main surface of the fluorine-treated substrate by dropping the light-absorbing composition G according to Example 1 using a dispenser. In order to prevent the light-absorbing composition from flowing and spreading endlessly on the substrate surface, a PTFE frame was placed on the substrate surface in advance, and the light-absorbing composition was spread inside the frame to form a coating film with a planar area of ​​approximately 76 mm square.

[0134] After the coating film of the light-absorbing composition was thoroughly dried at room temperature, it was placed inside a heating oven, and the temperature inside the heating oven was increased from room temperature to 85°C and heated for 6 hours. Thereafter, the heating was terminated, the temperature inside the heating oven was allowed to naturally decrease to approximately room temperature, and a fluorine-treated substrate containing a solidified coating film of the light-absorbing composition was removed. This heating process promoted the reaction of the alkoxysilane and volatilized the solvent contained in the light-absorbing composition. Furthermore, the solidified coating film of the light-absorbing composition was placed inside a heating and humidifying oven (high-temperature, high-humidity test chamber), and the interior of the high-temperature, high-humidity test chamber was heated and humidified from room temperature and normal humidity conditions to a temperature of 85°C and a relative humidity of 85%, and this condition was maintained for 16 hours. Thereafter, the interior of the high-temperature, high-humidity test chamber was gradually returned to room temperature and normal humidity conditions, and the fluorine-treated substrate containing the light absorber according to Example 1 was removed. Next, the light absorber was peeled off from the fluorine-treated substrate to obtain a film-like light absorber according to Example 1.

[0135] Example 2 6.73 g of Silicone KR-300 manufactured by Shin-Etsu Chemical Co., Ltd. was added to a light-absorbing composition prepared by the same method and conditions as in Example 1, and the mixture was stirred for 30 minutes to prepare a light-absorbing composition according to Example 2. The materials and their amounts used in preparing the light-absorbing composition according to Example 2 are shown in Tables 1 to 3. Table 4 shows ratios focusing on the amounts of specific components contained in the light-absorbing composition. Furthermore, a film-like light absorber according to Example 2 was prepared by the same method and conditions as in Example 1, except that the light-absorbing composition according to Example 2 was used instead of the light-absorbing composition according to Example 1.

[0136] Example 3 5.61 g of silicone KR-311 manufactured by Shin-Etsu Chemical Co., Ltd. was added to a light-absorbing composition prepared by the same method and conditions as in Example 1, and the mixture was stirred for 30 minutes to prepare a light-absorbing composition according to Example 3. The materials and their amounts used in preparing the light-absorbing composition according to Example 3 are shown in Tables 1 to 3. Table 4 shows ratios focusing on the amounts of specific components contained in the light-absorbing composition. Furthermore, a film-like light absorber according to Example 3 was prepared by the same method and conditions as in Example 1, except that the light-absorbing composition according to Example 3 was used instead of the light-absorbing composition according to Example 1.

[0137] Examples 4 to 9, 14, and 15 Light-absorbing compositions according to Examples 4 to 9, 14, and 15 were prepared by the same method and conditions as in Example 1, except that the materials and their amounts were adjusted as shown in Tables 1 to 3. Ratios focusing on the amounts of specific components contained in the light-absorbing compositions are shown in Table 4. Furthermore, film-like light absorbers according to Examples 4 to 9, 14, and 15 were prepared by the same method and conditions as in Example 1, except that the light-absorbing compositions according to Examples 4 to 9, 14, and 15 were used instead of the light-absorbing composition according to Example 1.

[0138] Examples 10 to 13 Light-absorbing compositions according to Examples 10 to 13 were prepared by the same method and conditions as in Example 1, except that the materials and their amounts were adjusted as shown in Tables 1 to 3. Table 4 shows ratios focusing on the amounts of specific components contained in the light-absorbing compositions. Light absorbers according to Examples 10 to 13 were prepared by solidifying coatings of the light-absorbing compositions according to Examples 10 to 13 in the same manner as in Example 1, except that a base glass substrate not treated with a fluorine compound and the light-absorbing compositions according to Examples 10 to 13 were used. The light absorbers according to Examples 10 to 13 were not peeled off from the base glass substrate. Therefore, the light absorbers according to Examples 10 to 13 were provided in a state where they were provided on the glass substrate.

[0139] Example 16 0.71 g of KBE-903 (3-aminopropyltriethoxysilane (3APTES)), an amino group-containing silane compound manufactured by Shin-Etsu Chemical Co., Ltd., was added to a light-absorbing composition prepared by the same method and conditions as in Example 6, and the mixture was stirred for 20 hours to prepare a light-absorbing composition according to Example 16. Ratios focusing on the amounts of specific components contained in the light-absorbing composition are shown in Table 4. Film-like light absorbers according to Example 16 were 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 the light-absorbing composition according to Example 1.

[0140] Examples 17 and 21 to 24 Light-absorbing compositions according to Examples 17 and 21 to 24 were prepared by the same method and conditions as in Example 16, except that the materials and their amounts were adjusted as shown in Tables 1 to 3. Ratios focusing on the amounts of specific components contained in the light-absorbing compositions are shown in Table 4. Film-like light absorbers according to Examples 17 and 21 to 24 were prepared by the same method and conditions as in Example 1, except that the light-absorbing compositions according to Examples 17 and 21 to 24 were used instead of the light-absorbing composition according to Example 1.

[0141] Example 18 A light-absorbing composition according to Example 1 was prepared by the same method and conditions as in Example 1, except that the materials and their amounts were adjusted as shown in Tables 1 and 2. 4.33 g of silicone KR-311 manufactured by Shin-Etsu Chemical Co., Ltd. and 0.57 g of KBE-903 (3APTES), an amino group-containing silane compound manufactured by Shin-Etsu Chemical Co., Ltd. (see Table 3), were added to the light-absorbing composition, and the mixture was stirred for 20 hours to prepare a light-absorbing composition according to Example 18. Table 4 shows the ratios focusing on the amounts of specific components contained in the light-absorbing composition. A film-like light absorber according to Example 18 was prepared by the same method and conditions as in Example 1, except that the light-absorbing composition according to Example 18 was used instead of the light-absorbing composition according to Example 1.

[0142] Example 19 A light-absorbing composition according to Example 19 was prepared by adding 0.14 g (see Table 3) of KBM-903 (3-aminopropyltrimethoxysilane (3APTMS)), an amino group-containing silane compound manufactured by Shin-Etsu Chemical Co., Ltd., to a light-absorbing composition prepared by the same method and conditions as in Example 1, except that the materials and their amounts were adjusted as shown in Tables 1 and 2. The mixture was stirred for 20 hours. Table 4 shows ratios focusing on the amounts of specific components contained in the light-absorbing composition. A film-like light absorber according to Example 19 was prepared by the same method and conditions as in Example 1, except that the light-absorbing composition according to Example 19 was used instead of the light-absorbing composition according to Example 1.

[0143] Example 20 A light-absorbing composition according to Example 20 was prepared by adding 0.53 g (see Table 3) of KBM-903 (3APTMS), an amino group-containing silane compound manufactured by Shin-Etsu Chemical Co., Ltd., to a light-absorbing composition prepared by the same method and conditions as in Example 1, except that the materials and their amounts were adjusted as shown in Tables 1 and 2. The mixture was stirred for 20 hours. Table 4 shows the ratios focusing on the amounts of specific components contained in the light-absorbing composition. A film-like light absorber according to Example 20 was prepared by the same method and conditions as in Example 1, except that the light-absorbing composition according to Example 20 was used instead of the light-absorbing composition according to Example 1.

[0144] <Comparative Examples 1 to 3> Light-absorbing compositions according to Comparative Examples 1 to 3 were produced by the same method and conditions as in Example 1, except that the materials and their amounts were adjusted as shown in Tables 1 to 3. Ratios focusing on the amounts of specific components contained in the light-absorbing compositions are shown in Table 4. Film-like light absorbers according to Comparative Examples 1 to 3 were produced by the same method and conditions as in Example 1, except that the light-absorbing compositions according to Comparative Examples 1 to 3 were used instead of the light-absorbing composition according to Example 1.

[0145] Comparative Example 4: 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, 1.646 g of Plysurf A208N (manufactured by 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 A'. 40 g of THF was added to 0.706 g of phenylphosphonic acid and stirred for 30 minutes to obtain Solution B'-1. 40 g of THF was added to 4.230 g of 4-bromophenylphosphonic acid and stirred for 30 minutes to obtain Solution B'-2. Next, Solution B'-1 and Solution B'-2 were mixed and stirred for 1 minute, and 8.664 g of methyltriethoxysilane (MTES: manufactured by Shin-Etsu Chemical Co., Ltd.) and 2.840 g of tetraethoxysilane (TEOS: manufactured by Kishida Chemical Co., Ltd., special grade) were added to this mixed solution and stirred for another 1 minute to obtain Solution B'. Solution B' was added to Solution A' while stirring, and the mixture was stirred at room temperature for 1 minute. Next, 140 g of toluene was added to this solution, and the mixture was stirred at room temperature for 1 minute to obtain Solution C'. Solution C' was placed in a flask and heated in an oil bath (manufactured by Tokyo Rikakikai Co., Ltd., model: OSB-2100), and a solvent removal treatment was carried out using a rotary evaporator (manufactured by Tokyo Rikakikai Co., Ltd., model: N-1110SF). The set temperature of the oil bath was adjusted to 105°C. Solution D' to be used in the light-absorbing composition of Comparative Example 8 after solvent removal treatment was then prepared from the flask. The solvent was not completely removed in the solvent removal treatment, but was removed so as to lower the viscosity of Solution D' to a certain extent. Solution D', which was a dispersion of fine particles of a compound containing phenylphosphonic acid, copper 4-bromophenylphosphonate, and a copper component, was transparent, and the fine particles were well dispersed in Solution D'.

[0146] Next, 4.500 g of copper acetate monohydrate and 240 g of THF were mixed and stirred for 3 hours to obtain a copper acetate solution. Next, 2.572 g of Plysurf A208N, a phosphate ester compound, was added to the obtained copper acetate solution and stirred for 30 minutes to obtain Solution E'. Furthermore, 40 g of THF was added to 2.886 g of n-butylphosphonic acid and stirred for 30 minutes to obtain Solution F'. Solution F' was added to Solution E' while stirring, and the mixture was stirred at room temperature for 1 minute. Next, 84 g of toluene was added to this solution, and the mixture was stirred at room temperature for 1 minute to obtain Solution G'. Solution G' was placed in a flask and heated in an oil bath, whereupon a solvent removal treatment was carried out using a rotary evaporator. The set temperature of the oil bath was adjusted to 105°C. Solution H', which was used in the light-absorbing composition of Comparative Example 8 after solvent removal treatment, was then prepared from the flask. The solvent was not completely removed in the solvent removal treatment, but rather the solvent was removed so that the viscosity of Solution H' reached a predetermined value. Liquid H', which was a dispersion of fine particles of a compound containing butylphosphonic acid and a copper component, was transparent, and the fine particles were well dispersed in Liquid H'.

[0147] 10.69 g of silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KR-300) was added to Solution D' and stirred for 30 minutes to obtain Solution I'. 27.25 g of Solution H', equivalent to 40 mass % of the total amount of Solution H', was added to Solution I' and stirred for 30 minutes to prepare the light-absorbing composition of Comparative Example 4. The materials and their amounts used to prepare the light-absorbing composition of Comparative Example 4 are shown in Tables 1 to 3. Table 4 shows the ratios focusing on the amounts of specific components contained in the light-absorbing composition.

[0148] A film-shaped light absorber according to Comparative Example 4 was produced by the same method and conditions as in Example 1, except that the light-absorbing composition according to Comparative Example 4 was used instead of the light-absorbing composition according to Example 1.

[0149] Comparative Example 5 1.125 g of copper acetate monohydrate and 60 g of tetrahydrofuran (THF) were mixed and stirred for 3 hours to obtain a copper acetate solution. Next, 0.412 g of Plysurf A208N (manufactured by 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 A". 10 g of THF was added to 0.441 g of phenylphosphonic acid and stirred for 30 minutes to obtain solution B"-1. 10 g of THF was added to 0.661 g of 4-bromophenylphosphonic acid and stirred for 30 minutes to obtain solution B"-2. Next, solutions B"-1 and B"-2 were mixed and stirred for 1 minute, and then 1.934 g of methyltriethoxysilane (MTES: manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.634 g of tetraethoxysilane (TEOS: manufactured by Kishida Chemical Co., Ltd., special grade) were added to this mixed solution and stirred for another 1 minute to obtain solution B". While stirring solution A", solution B" was added to solution A", and stirred for 1 minute at room temperature. Next, 25 g of toluene was added to this solution, and then stirred for 1 minute at room temperature to obtain solution C". This solution C" was placed in a flask and heated in an oil bath (manufactured by Tokyo Rikakikai Co., Ltd., model: OSB-2100), while undergoing a solvent removal treatment using a rotary evaporator (manufactured by Tokyo Rikakikai Co., Ltd., model: N-1110SF). The set temperature of the oil bath was adjusted to 105°C. Thereafter, solution D" to be used in the light-absorbing composition according to Comparative Example 9 after solvent removal treatment was prepared from the flask. Solution D" which was a dispersion of fine particles of a compound containing phenylphosphonic acid, 4-bromophenylphosphonic acid, and a copper component was transparent, and the fine particles were well dispersed in solution D".

[0150] Next, 1.125 g of copper acetate monohydrate and 60 g of THF were mixed and stirred for 3 hours to obtain a copper acetate solution. Next, 0.710 g of Plysurf A208N, a phosphate ester compound, was added to the obtained copper acetate solution and stirred for 30 minutes to obtain solution E". Furthermore, 10 g of THF was added to 0.708 g of n-butylphosphonic acid and stirred for 30 minutes to obtain solution F". Solution F" was added to solution E" while stirring, and stirred at room temperature for 1 minute. Next, 25 g of toluene was added to this solution, and stirred at room temperature for 1 minute to obtain solution G". Solution G" was placed in a flask and heated in an oil bath, whereupon a solvent removal treatment was performed using a rotary evaporator. The set temperature of the oil bath was adjusted to 105°C. Solution H" was then prepared from the flask and used in the light-absorbing composition of Comparative Example 9 after the solvent removal treatment. Liquid H″, which was a dispersion of fine particles of a compound containing butylphosphonic acid and a copper component, was transparent, and the fine particles were well dispersed in liquid H″.

[0151] Furthermore, 2.200 g of silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KR-300) was added to the D" solution and stirred for 30 minutes, yielding the I" solution. The H" solution, equivalent to 20 mass % of the total amount of the H" solution, was added to the I" solution and stirred for 30 minutes, yielding the light-absorbing composition according to Comparative Example 5. The materials and their amounts used in producing the light-absorbing composition according to Comparative Example 5 are shown in Tables 1 to 3. The ratios focusing on the amounts of specific components contained in the light-absorbing composition are shown in Table 4.

[0152] A film-shaped light absorber according to Comparative Example 5 was produced by the same method and conditions as in Example 1, except that the light-absorbing composition according to Comparative Example 5 was used instead of the light-absorbing composition according to Example 1.

[0153] Comparative Example 6: 1.125 g of copper acetate monohydrate and 60 g of tetrahydrofuran (THF) were mixed and stirred for 3 hours to obtain Solution A'". Next, 10 g of THF was added to 0.447 g of phenylphosphonic acid and stirred for 30 minutes to obtain Solution B'"-1. Furthermore, 10 g of THF was added to 0.670 g of 4-bromophenylphosphonic acid and stirred for 30 minutes to obtain Solution B'"-2. Next, Solutions B'"-1 and B'"-2 were mixed and stirred for 1 minute, and 5.415 g of methyltriethoxysilane (MTES) and 1.775 g of tetraethoxysilane (TEOS) were added and stirred for another 1 minute to obtain Solution B'". Solution B'" was added to Solution A'" while stirring, and the mixture was stirred at room temperature for 1 minute. Next, 40 g of toluene was added to this solution and the mixture was stirred at room temperature for 1 minute to obtain Solution C'". This solution C''' was placed in a flask and heated in an oil bath (Tokyo Rikakikai Co., Ltd., model: OSB-2100), while a solvent removal treatment was carried out using a rotary evaporator (Tokyo Rikakikai Co., Ltd., model: N-1110SF). The temperature of the oil bath was adjusted to 85°C. Then, solution D''' after the solvent removal treatment was removed from the flask. Solution D''', which is a dispersion of fine particles of phenyl-based copper phosphonate (light absorber), was transparent, and the fine particles were well dispersed.

[0154] Next, 0.450 g of copper acetate monohydrate and 24 g of THF were mixed and stirred for 3 hours to obtain solution E'". Furthermore, 10 g of THF was added to 0.257 g of n-butylphosphonic acid and stirred for 30 minutes, and then 2.166 g of methyltriethoxysilane (MTES) and 0.710 g of tetraethoxysilane (TEOS) were added and stirred for another 1 minute to obtain solution F'". Solution F'" was added to solution E'" while stirring, and stirred at room temperature for 1 minute. Next, 16 g of toluene was added to this solution, and stirred at room temperature for 1 minute to obtain solution G'". Solution G'" was placed in a flask and heated in an oil bath, whereupon the solvent was removed using a rotary evaporator. The oil bath temperature was adjusted to 85°C. After the solvent removal treatment, solution H'" was then removed from the flask. Liquid H''', which was a dispersion of fine particles of copper butylphosphonate (light absorber), was transparent, and the fine particles were well dispersed.

[0155] 16 g of silicone resin KR-311 (manufactured by Shin-Etsu Chemical Co., Ltd.) and 4 g of silicone resin KR-300 (manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed and stirred for 10 minutes to obtain resin composition Y'". 8.800 g of resin composition Y'" was added to liquid D'" and stirred for 5 minutes to obtain liquid I'". Liquid H'" was added to the obtained liquid I'" and stirred for 10 minutes to obtain a light-absorbing composition according to Comparative Example 6. The materials and their amounts used to prepare the light-absorbing composition according to Comparative Example 6 are shown in Tables 1 to 3. Table 4 shows the ratios focusing on the amounts of specific components contained in the light-absorbing composition.

[0156] A film-shaped light absorber according to Comparative Example 6 was produced by the same method and conditions as in Example 1, except that the light-absorbing composition according to Comparative Example 6 was used instead of the light-absorbing composition according to Example 1.

[0157] (Transmission Spectrum Measurement) The transmission spectra of the light absorbers according to each Example and Comparative Examples 3 to 6 were measured. A V-770 ultraviolet-visible-near-infrared spectrophotometer manufactured by JASCO Corporation was used as the measurement device. The transmission spectrum of the light absorber was obtained by irradiating light having wavelengths of 300 nm to 1200 nm onto the light absorber at an incident angle of 0° and measuring the transmittance for each wavelength (1 nm) of the transmitted light. Unless otherwise specified, the transmission spectrum measurements were performed under conditions where the ambient temperature of the light absorber was 22 to 25°C. The transmission spectra of the light absorbers according to Examples 1 to 4, 7, 8, 16, and 24 are shown in Figures 5 to 8, 9, 10, 11, and 12, respectively. The transmission spectra of the light absorbers according to Comparative Examples 3 and 6 are shown in Figures 13 and 14, respectively. The wavelength and transmittance values ​​for multiple properties observed or calculated from the transmission spectrum of each light absorber are shown in Table 5.

[0158] (Thickness Measurement) The thickness of the light absorber was measured using a laser displacement meter LK-H008 manufactured by Keyence Corp. The results are shown in Table 5.

[0159] (Haze Measurement) Using a haze meter (manufactured by Murakami Color Research Laboratory, product name: HM-65L2), the haze of each light absorber was measured in accordance with JIS K 7136:2000 (Japanese Industrial Standards). When the obtained haze was 0.50% or less, it was evaluated as "A", when it was more than 0.50% and 1.00% or less, it was evaluated as "B", and when it was more than 1.00%, it was evaluated as "C". The evaluation results are shown in Table 5.

[0160] (Moisture Resistance Test) A moisture resistance test was performed in which each light absorber was placed in an environment of a temperature of 85°C and a relative humidity of 85% for 250 hours and 1000 hours, and after this moisture resistance test, light was made incident on the light absorber at an incident angle of 0° to obtain a transmission spectrum. As a result, the average transmittance at wavelengths of 400 to 580 nm before and after the moisture resistance test was compared. When the change in this average transmittance before and after the moisture resistance test was 3 points or less, it was evaluated as "A," and when it was more than 3 points, it was evaluated as "C." The evaluation results are shown in Table 5.

[0161] A moisture resistance test was performed in which the light absorbers according to Examples 2, 3, 5, 6, 16, 19, and 21 were placed in an environment of a temperature of 85°C and a relative humidity of 85% for 1000 hours, and the transmission spectrum of each light absorber was measured before the test and at 240 hours, 480 hours, 720 hours, and 1000 hours after the start of the test. These transmission spectra of the light absorbers according to Examples 2, 3, 5, 6, 16, 19, and 21 are shown in Fig. 15, Fig. 16, Fig. 17, Fig. 18, Fig. 19, Fig. 20, and Fig. 21, respectively. The differences obtained by subtracting the maximum value from the minimum value of the average transmittance within a wavelength range of 400 to 580 nm in the transmission spectra of the light absorbers according to these examples before the test, and 240 hours, 480 hours, 720 hours, and 1000 hours after the start of the test were 1.10% (Example 2), 1.32% (Example 3), 1.40% (Example 5), 1.59% (Example 6), 1.87% (Example 16), 2.49% (Example 19), and 2.71% (Example 21). Even after a humidity resistance test at high temperatures, the fluctuations in the average transmittance in the transmission range of 400 nm to 580 nm were suppressed to within 3% for these light absorbers. As shown in FIGS. 15 to 21, the transmittance at a wavelength of 800 nm in these transmission spectra was 5% or less.

[0162] According to the results of the moisture resistance test of the light absorbers according to the respective Examples, the change in average transmittance at wavelengths of 400 to 580 nm before and after the moisture resistance test of each light absorber was 3 points or less, and the result of the moisture resistance test was evaluated as "A." Therefore, it is understood that the light absorbers according to the respective Examples can exhibit desired moisture resistance.

[0163] The light-absorbing composition according to Comparative Example 1 became significantly turbid, and a transparent light absorber could not be produced. It is presumed that in Comparative Example 1, the effect of suppressing aggregation of the produced copper phosphonate compound was insufficient because the number of carbon atoms in the alkyl group directly bonded to the silicon atom in the added trifunctional alkoxysilane was as small as 6.

[0164] Although the light-absorbing composition of Comparative Example 2 contained a large amount of the trifunctional alkoxysilane, significant turbidity occurred. A light absorber could be produced using the light-absorbing composition of Comparative Example 3, which contained an even larger amount of the trifunctional silane. However, as shown in FIG. 13 , the transmittance of the light absorber of Comparative Example 3 in the visible light range was low. In addition, the haze of the light absorber of Comparative Example 3 was very high, and it was difficult to say that the light absorber of Comparative Example 3 had good optical properties. These results suggest that when the number of carbon atoms in the alkyl group of the trifunctional linear alkylsilane is less than 10, the aggregation suppression effect of copper phosphonate is not sufficiently obtained, making it difficult to produce a light absorber and optical filter with good optical properties.

[0165] According to the results of the moisture resistance test of the light absorbers according to Comparative Examples 4 and 5, the fluctuation in the average transmittance at wavelengths of 400 nm to 580 nm was small after 250 hours, but after 1000 hours, the entire light absorber became cloudy and the transmittance significantly decreased. This is presumably due to the hydrolysis of a portion of the phosphate ester added to the light-absorbing composition to homogeneously disperse the copper phosphonate in the liquid and suppress aggregation, caused by the long-term moisture treatment. From the above, it can be said that the light-absorbing composition of Comparative Example 4 has moisture resistance sufficient to withstand a high-temperature, high-humidity environment for a short period of time, but it was found that it cannot withstand a harsh high-temperature, high-humidity environment for a long period of time, for example, 1000 hours at a temperature of 85°C and a relative humidity of 85%.

[0166] The transmission spectrum of the light absorber according to Comparative Example 6 confirms that the transmittance is high in the wavelength range of 750 to 1100 nm and low in the wavelength range of 460 to 600 nm. This indicates that the visible light transmittance is significantly low when the near-infrared absorption is insufficient, and therefore the composition does not have the optical properties required for an optical filter. The alkoxysilanes used in the light-absorbing composition according to Comparative Example 6 are only MTES and TEOS, and do not contain a trifunctional alkoxysilane with a large number of carbon atoms in the alkyl group. The alkyl group of MTES, which is a trifunctional alkoxysilane, has one carbon atom. This suggests that the light absorber according to Comparative Example 6 does not have good optical properties. Comparative Example 6 suggests that the inclusion of an alkoxysilane or the like containing a group having 10 or more carbon atoms is important for obtaining good optical properties.

[0167]

[0168]

[0169]

[0170]

[0171]

Claims

1. A light-absorbing composition comprising at least one selected from the group consisting of a primary alkoxysilane represented by the following formula (1), a hydrolyzate of the primary alkoxysilane, and a polymer of the hydrolyzate of the primary alkoxysilane, and a light-absorbing compound. 11 4-n Si(OR 12 ) n 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 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.

2. The light-absorbing composition according to claim 1, further comprising at least one selected from the group consisting of a secondary alkoxysilane represented by the following formula (2), a hydrolyzate of the secondary alkoxysilane, and a polymer of the hydrolyzate of the secondary alkoxysilane: 21 4-m Si(OR 22 ) m Formula (2): In formula (2), m is an integer of 3 or 4, and R 21 and R 22 may be the same or different, and R 21 and R 22 Each of the groups is a group containing at least a carbon atom (C) and a hydrogen atom (H).

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

4. The light-absorbing composition according to claim 3, wherein the molar ratio of silicon atoms contained in the primary alkoxysilane, the hydrolyzate of the primary alkoxysilane, and the polymer of the hydrolyzate of the primary alkoxysilane to the copper component is 0.30 to 4.

00.

5. The light-absorbing composition according to claim 3 or 4, wherein the molar ratio of said phosphonic acid component to said copper component is 0.80 to 1.

20.

6. The light-absorbing composition according to any one of claims 3 to 5, wherein the molar ratio of silicon atoms contained in the primary alkoxysilane, the hydrolysate of the primary alkoxysilane, and the polymer of the hydrolysate of the primary alkoxysilane to the phosphonic acid component is 0.10 to 3.

00.

7. A light-absorbing composition comprising at least one selected from the group consisting of a primary alkoxysilane represented by the following formula (1), a hydrolysate of the primary alkoxysilane, and a polymer of the hydrolysate of the primary alkoxysilane, at least one selected from the group consisting of a tertiary alkoxysilane represented by the following formula (3), a hydrolysate of the tertiary alkoxysilane, and a polymer of the hydrolysate of the tertiary alkoxysilane, and a light-absorbing compound. 11 4-n Si(OR 12 ) n Formula (1) R 31 4-p Si(OR 32 ) p Formula (3) In formula (1), n ​​is 1, 2, or 3, and R 11 is a group containing at least a carbon atom (C) and a hydrogen atom (H), and R 11 At least one of R is a group 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 In formula (3), p is 1, 2, or 3, and R 31 is a group containing at least a carbon atom (C), a hydrogen atom (H), and an amino group (—NH), and the hydrogen atom (H) in the amino group may be substituted with a halogen atom, an alkyl group, or an aryl group; R 32 is a group containing at least a carbon atom (C) and a hydrogen atom (H).

8. The light-absorbing composition according to claim 7, wherein the light-absorbing compound comprises a copper component and a phosphonic acid component, and the molar ratio of silicon atoms contained in the tertiary alkoxysilane, the hydrolyzate of the tertiary alkoxysilane, and the polymer of the hydrolyzate of the tertiary alkoxysilane to the copper component is 0.01 to 1.

00.

9. The light-absorbing composition according to claim 7 or 8, wherein the light-absorbing compound comprises a copper component and a phosphonic acid component, and the molar ratio of the phosphonic acid component to the copper component is 0.80 to 1.

40.

10. The light-absorbing composition according to any one of claims 1 to 9, wherein the transmission spectrum of a light absorber formed by said light-absorbing composition when irradiated with light having a wavelength of 300 nm to 1200 nm at an incident angle of 0° satisfies the following (i), (ii), and (iii): (i) an average transmittance in the wavelength range of 460 nm to 600 nm of 80% or more; (ii) an average transmittance in the wavelength range of 300 nm to 380 nm of 1.2% or less; and (iii) an average transmittance in the wavelength range of 750 nm to 1100 nm of 2.0% or less.

11. The light-absorbing composition according to any one of claims 1 to 10, wherein the transmission spectrum of a light absorber formed by the light-absorbing composition when light having a wavelength of 300 nm to 1200 nm is incident at an incident angle of 0° satisfies the following (iv) and (v): (iv) a first cutoff wavelength within a wavelength range of 380 nm to 440 nm at which the transmittance is 50%; and (v) a second cutoff wavelength within a wavelength range of 600 nm to 680 nm at which the transmittance is 50%.

12. A light-absorbing composition according to any one of claims 1 to 11, wherein the absolute value of the difference in average transmittance within a wavelength range of 400 nm to 580 nm between the transmission spectrum obtained when light having a wavelength of 300 nm to 1200 nm is incident on the light absorber at an incident angle of 0° after a test in which the light absorber formed from the light-absorbing composition is exposed to an environment at a temperature of 85°C and a relative humidity of 85% for 1000 hours and the transmission spectrum obtained when light having a wavelength of 300 nm to 1200 nm is incident on the light absorber at an incident angle of 0° before the test is 3% or less.

13. A light absorber comprising: silica; at least one selected from the group consisting of polyorganosilsesquioxanes and polydiorganosiloxanes containing a group having 10 or more carbon atoms; and a light absorbing compound containing a phosphonic acid and a copper component.

14. The light absorber according to claim 13, wherein the transmission spectrum when light having a wavelength of 300 nm to 1200 nm is incident at an incident angle of 0° satisfies the following (I), (II), and (III): (I) the average value of the transmittance in the wavelength range of 460 nm to 600 nm is 80% or more; (II) the average value of the transmittance in the wavelength range of 300 nm to 380 nm is 1.2% or less; and (III) the average value of the transmittance in the wavelength range of 750 nm to 1100 nm is 2.0% or less.

15. The light absorber according to claim 13 or 14, comprising a nitrogen atom directly bonded to a silicon atom.

16. An optical filter comprising the light absorber according to any one of claims 13 to 15.

17. The optical filter according to claim 16, further comprising an anti-reflection film provided on the surface of the light absorber.

18. The optical filter according to claim 17, wherein the antireflection coating comprises 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; or (c) a layer containing SiO2, TiO2, Ta2O3, SnO2, In2O3, Nb2O5, Si3N4, TiN x and a layer containing at least one material selected from the group consisting of MgF2 19. The optical filter according to claim 18, wherein the layer (b1) contains hollow particles having a refractive index of 1.02 to 1.

50.

20. The optical filter according to claim 18 or 19, wherein the layer (c) is composed of one layer or two or more layers made of different materials.

21. The optical filter according to any one of claims 18 to 20, wherein the anti-reflection film includes the layer (b1) and the layer (b2), and the refractive index of the layer (b2) is higher than the refractive index of the layer (b1).

22. The optical filter according to any one of claims 18 to 21, wherein the layer (b2) contains solid particles having a refractive index of 1.25 to 2.

75.

23. An ambient light sensor comprising a light absorber according to any one of claims 13 to 15.

24. An imaging device comprising the light absorber according to any one of claims 13 to 15.

25. A method for producing a light-absorbing composition, 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 a primary alkoxysilane represented by the following formula (1) or a hydrolyzate of the primary alkoxysilane; and removing a portion of the solvent from the light-absorbing compound dispersion. 11 4-n Si(OR 12 ) n 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 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.

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