Liquid composition, film, optical component, optical device, and method for manufacturing optical device

Abstract

This liquid composition contains: hollow particles 11; at least one selected from the group consisting of alkoxysilanes and hydrolysates of alkoxysilanes; and a water-absorbing resin. The liquid composition is solidified, whereby it is possible to form a film therefrom. The film has a refractive index of 1.15-1.65.

Description

Liquid composition, film, optical component, optical device, and method for manufacturing optical device

[0001] The present invention relates to a liquid composition, a film, an optical component, an optical device, and a method for manufacturing an optical device.

[0002] Conventionally, techniques for preventing or reducing light reflection from the surface of an object have been known. For example, when reflected light occurs in a camera module or the like, reflection and refraction occur within the camera module or the housing housing the camera module. Light rays that do not contribute to the formation of the desired image may reach an imaging element such as a charge-coupled device (CCD) or CMOS image sensor, resulting in phenomena that degrade image quality, such as flare or ghosting. Flare is a phenomenon in which the contrast of an image is significantly reduced, as if part or all of it were hazy. Ghosting is a phenomenon in which an image of, for example, an aperture or housing frame is formed on an imaging element by reflected light or repeatedly reflected light, resulting in the inclusion of an image that does not actually exist as a subject.

[0003] For example, when the temperature of the surface of a lens mounted on or included in a camera drops below the dew point, water vapor adheres to the lens surface and appears as tiny droplets. When an image is captured using a lens in this state, the resulting image appears hazy, as if it were taken in fog. For example, this phenomenon may occur in an in-vehicle camera or a camera mounted on another moving object, where high and low ambient temperatures may alternate. It may be necessary to capture images or take photographs under such conditions.

[0004] For example, Patent Document 1 describes an antireflection coating provided on a substrate such as a lens. This antireflection coating comprises an intermediate layer provided on the substrate and a low refractive index layer provided on the surface of the intermediate layer. The low refractive index layer contains hollow silica and a metal alkoxide compound, as well as a binder for binding the hollow silica. In this antireflection coating, a parameter derived from the relationship between the refractive indices of the substrate, the intermediate layer, and the low refractive index layer falls within a specific range, thereby achieving low reflectance within an appropriate band.

[0005] JP 2012-215790 A

[0006] The technologies described in the above patent documents do not consider the possibility that the surface of some lenses may become cloudy due to the hot-cold cycles to which the lenses are exposed, and the technologies described in the patent documents have room for reexamination from the perspective of achieving both anti-fogging and anti-reflection properties with a simple configuration. Therefore, the present invention provides a technology that is advantageous from the perspective of achieving both anti-fogging and anti-reflection properties with a simple configuration.

[0007] The present invention provides a liquid composition comprising hollow particles, at least one selected from the group consisting of alkoxysilanes and hydrolysates of alkoxysilanes, and a water-absorbent resin, wherein the liquid composition can form a film by solidification, and the film has a refractive index of 1.15 to 1.65.

[0008] The present invention also provides a film comprising: hollow particles; at least one selected from the group consisting of silica and silsesquioxane; and a water-absorbing resin; and having a refractive index of 1.15 to 1.65.

[0009] The present invention also provides an optical component comprising: a substrate; and a film provided on the substrate, wherein the film contains hollow particles, at least one selected from the group consisting of silica and silsesquioxane, and a water-absorbing resin, and the film has a refractive index of 1.15 to 1.65.

[0010] The present invention also provides an optical device including the above optical component.

[0011] The present invention also provides an optical device comprising: a housing; and a plurality of lenses arranged inside the housing, the plurality of lenses having a plurality of inner surfaces, and the above-mentioned film being provided on at least one of the plurality of inner surfaces.

[0012] The present invention also provides a method for manufacturing an optical device, comprising: forming the above-mentioned film on a surface of at least one of a first lens and a second lens; and integrating a lens group including the first lens and the second lens in a housing so that the second lens is located next to the first lens, wherein the surface on which the film is formed faces the space between the first lens and the second lens.

[0013] The above liquid composition is advantageous from the viewpoint of achieving both anti-fogging properties and anti-reflection properties with a simple configuration.

[0014] FIG. 1 is a cross-sectional view schematically showing an example of a film according to the present invention. FIG. 2 is a cross-sectional view schematically showing an example of an optical component according to the present invention. FIG. 3 is a cross-sectional view schematically showing an example of an optical device according to the present invention. FIG. 4 is a cross-sectional view schematically showing another application example of a film according to the present invention. FIG. 5 is a graph showing the reflection spectra of optical films according to Examples 19, 20, 22, 23, and 24. FIG. 6 is a graph showing the reflection spectra of optical films according to Examples 29, 30, 31, 32, and 33. FIG. 7 is a graph showing the reflection spectrum of a plate-shaped substrate made of soda-lime glass before an optical film is formed. FIG. 8 is a graph showing the relationship between the refractive index at a wavelength of 550 nm of the optical films according to Examples 19, 20, 22, 23, 24, 29, 30, 31, 32, and 33 and the ratio of the mass of the water-absorbent resin to the mass of the film.

[0015] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that the following description is for illustrative purposes only and is not intended to limit the scope of the present invention.

[0016] As shown in FIG. 1 , the film 1a includes hollow particles 11 and a binder 12. The binder 12 includes, for example, at least one silicon oxide selected from the group consisting of silica and silsesquioxane, and a water-absorbing resin. The film 1a has a refractive index of 1.15 to 1.65. As described below, in this specification, unless otherwise specified, the refractive index refers to the refractive index at a wavelength of 550 nm. The film 1a is disposed on, for example, a substrate 2 and reduces reflected light from the substrate 2 compared to when the film 1a is not present. In other words, the film 1a can exhibit anti-reflection properties. Anti-reflection does not mean reducing a physical quantity, such as the radiant flux of reflected light, to substantially zero. In this specification, at least one selected from the group consisting of a reduction in reflectance, a reduction in the radiant flux of reflected light, a reduction in the radiant intensity of reflected light, a reduction in the radiance of reflected light, a reduction in the irradiance of reflected light, and a reduction in the radiant energy of reflected light can be considered as reduction in reflected light or anti-reflection. In this specification, unless otherwise specified, a reduction in reflectance measured by a spectrophotometer or the like can be considered as a reduction in reflected light or prevention of reflection.

[0017] The film 1a can exhibit anti-fogging properties under certain circumstances. When fine droplets adhere to the surface of the substrate, light transmission can be hindered, potentially causing fogging. For example, under certain conditions, countless fine droplets may adhere to the surface of the substrate, making it impossible to accurately see from one side of the substrate to the other. The ability to suppress the occurrence of this fogging phenomenon to some extent is called anti-fog or anti-fogging.

[0018] Important properties for achieving anti-fogging include, for example, hydrophilicity and water absorbency. High hydrophilicity improves the wettability (wetness) of the substrate surface with liquid substances such as water, making it less likely for droplets to form on the substrate surface. High water absorbency makes it easier for liquid substances present on or near the substrate surface to be absorbed into the film or the like before forming droplets on the substrate surface. Hydrophilicity can be enhanced by forming a hydrophilic film on the surface of the substrate or the like. For example, forming a film containing a compound having many hydrophilic groups, such as hydroxyl groups, on the surface of the substrate tends to enhance hydrophilicity. Water absorbency can be enhanced by forming a porous film having many voids inside that can absorb liquids such as water, or a film containing a compound with relatively high water absorbency.

[0019] The film 1a is, for example, an optical film having antifogging and antireflection properties. The film 1a may be a film that is not expected to exhibit any optical function or does not exhibit any optical function.

[0020] As described above, the binder 12 in the film 1a contains the silicon oxide, which makes it easy to exhibit the desired hydrophilicity. In addition, the binder 12 contains a water-absorbent resin, which makes it easy to exhibit the desired water absorption.

[0021] The water absorption rate of the membrane 1a is not limited to a specific value. The water absorption rate may be determined, for example, in accordance with Japanese Industrial Standards (JIS) K 7209:2000, or by dividing the weight difference of a test piece before and after a water absorption test in which the test piece is made to absorb water under predetermined conditions by the volume of the test piece before the water absorption test. When the membrane 1a is provided on the surface of a substrate, the water absorption performance of the membrane 1a may be expressed as the volume of the internal or external space facing the membrane 1a. For example, the volume of the space facing the membrane 1a is preferably 0.01 cm. 3 ~10cm 3 and more preferably 0.1 cm 3 ~5cm 3 and more preferably 0.1 cm 3 ~1cm 3As will be described later, when the antireflection coating has a single-layer structure, the necessary thickness of the antireflection coating is 60 nm to 500 nm, and particularly preferably about 100 nm. For example, such a thin film that can achieve both antireflection performance and antifogging performance can be put into practical use by a significantly simple manufacturing method.

[0022] The refractive index n of the film 1a at a wavelength of 550 nm f is, for example, the refractive index n of the substrate 2 at a wavelength of 550 nm. b The refractive index n f is, for example, 1.15 to 1.65. For example, when the substrate 2 is included in an optical component, the refractive index n b is about 1.5 to 2.8. Therefore, the refractive index n f is the refractive index n b or refractive index n f In many cases where the substrate 2 is included in an optical component, the refractive index falling within the above range can suppress reflected light from the surface of the substrate 2. In this specification, unless otherwise specified, the refractive index refers to the refractive index at a wavelength of 550 nm.

[0023] Refractive index n f When the refractive index n is 1.15 or more, the content of the hollow particles 11 and the content of the binder 12 in the film 1a can be adjusted to a desired range, and the film 1a can easily exhibit a desired strength, which is advantageous from the viewpoint of practicality. f When the refractive index n is 1.65 or less, the range of optical components to which the substrate 2 on which the film 1a is formed is not likely to be limited, and the substrate 2 on which the film 1a is formed can be used in many optical components. Therefore, the commercial flow of optical components is not likely to be restricted. f is preferably 1.15 to 1.55, more preferably 1.15 to 1.45, and even more preferably 1.15 to 1.35.

[0024] The thickness d of the film 1a is not limited to a specific value. The thickness d of the film 1a is, for example, 60 nm to 500 nm. In this case, the hollow particles 11 are likely to be arranged in a desired state in the film 1a, and the desired antireflection properties are likely to be exhibited. The thickness d is preferably 60 nm to 400 nm, more preferably 60 nm to 300 nm, even more preferably 70 nm to 200 nm, and particularly preferably 80 nm to 150 nm.

[0025] When the relationship of the following formula (A) is satisfied in a film, the film is likely to exhibit desirable anti-reflection performance. λ0 is the applicable wavelength, which is the wavelength at which anti-reflection performance is expected to be exhibited. n(λ0) is the refractive index of the film at the applicable wavelength λ0. d is the thickness of the film. In particular, when a film is provided on a substrate, the refractive index n0 of the substrate at the applicable wavelength λ0 is (n0) 0.5 = n(λ0) and the condition of formula (A) are satisfied, the reflectance will theoretically be zero. The applicable wavelength may be any wavelength included in the wavelength range in which anti-reflection performance is expected to be exhibited, or may be the center wavelength corresponding to the center value in that wavelength range. n(λ0) × d = λ0 / 4 Formula (A)

[0026] In the film 1a, it is desirable that the relationship of formula (A) is satisfied or is approximated as being satisfied. In this case, the film 1a is likely to exhibit the desired anti-reflection performance. For example, when the condition 0.8×λ / 4≦n(λ)×d≦1.2×λ / 4 is satisfied, it can be approximated as being satisfied as being satisfied as being satisfied as being satisfied as being satisfied as being satisfied as being satisfied as being satisfied as being satisfied as being satisfied as being satisfied as being satisfied as being satisfied as being satisfied as being satisfied as being satisfied as being satisfied as being satisfied as being satisfied as being satisfied as being satisfied as being the case ...

[0027] In the film 1a, the refractive index n f and the ratio r of the mass of the water-absorbent resin to the mass of the membrane 1a fr The relationship between the refractive index n and the refractive index n of the film 1a is not limited to a specific relationship. f and ratio r fr Desirably, 0.3685×(r fr ) + 1.12 ≦ n f ≦0.3685×(r fr )+1.21 Formula (B)

[0028] The arithmetic mean roughness Ra of the surface of the film 1a is not limited to a specific value. The arithmetic mean roughness Ra of the surface of the film 1a is, for example, 5 nm to 50 nm. Because the film 1a contains hollow particles 11, fine irregularities can be formed within the surface of the film 1a. When the arithmetic mean roughness Ra of the surface of the film 1a is within the above range, the surface of the film 1a and its vicinity are in a state where the solid material constituting the film 1a and air are mixed. As a result, it is expected that the refractive index will be substantially reduced in a range of several tens of nanometers from the surface of the film 1a and its vicinity. When the arithmetic mean roughness Ra of the surface of the film 1a is 5 nm or more, such a substantial reduction in refractive index can be expected. When the arithmetic mean roughness Ra of the surface of the film 1a is 50 nm or less, Rayleigh scattering can occur depending on the wavelength applied to an article including the film 1a, thereby reducing the increase in haze of the film 1a or an optical component provided with the film 1a. The arithmetic mean roughness Ra of the surface of the film 1a is preferably 10 nm to 40 nm, and more preferably 15 nm to 35 nm. The arithmetic mean roughness Ra can be determined based on JIS B 0601-2001.

[0029] Ten-point average roughness Rz of the surface of the film 1a JIS is not limited to a specific value. The ten-point average roughness Rz of the surface of the film 1a JIS is, for example, 300 nm or less. When aggregation of the hollow particles 11 occurs, unevenness including the difference between the peak and the valley (P-V difference) falling within the above range may be formed within the surface of the film 1a. The ten-point average roughness Rz of the surface of the film 1a JIS When the surface roughness Rz of the film 1a is 300 nm or less, the P-V difference is unlikely to reach 1 / 3 to 1 / 2, and the influence of the surface of the film 1a on refraction and scattering is likely to be small. JIS is preferably 120 nm to 280 nm, and more preferably 150 nm to 260 nm.

[0030] As shown in FIG. 1, the film 1a has, for example, voids 13 therein. The voids 13 are spaces not occupied by liquid or solid, and are typically filled with air. Since the refractive index of air is 1, the presence of voids 13 within the film 1a can contribute to a decrease in the refractive index of the film 1a. On the other hand, the number of voids 13 can affect the mechanical strength of the film 1a. The porosity of the film 1a is, for example, 5% to 80%. In this case, the film 1a is likely to have the desired refractive index and mechanical strength. For example, a cross section of the film 1a formed along a plane perpendicular to the film surface of the film 1a is observed with a scanning electron microscope (SEM). The porosity can be determined, for example, based on the results of such SEM observation, by dividing the area occupied by voids within a 500 nm length range along the boundary between the film 1a and the substrate 2 by the total area of ​​the film 1a within that range.

[0031] The film 1a is formed, for example, by a wet method. A liquid composition is used to form the film 1a. This liquid composition contains, for example, hollow particles 11, at least one silicon-containing compound selected from the group consisting of alkoxysilanes and alkoxysilane hydrolysates, and a water-absorbent resin. The film 1a can be formed by solidifying the liquid composition. For example, the liquid composition is applied to the surface of the substrate 2, and the resulting coating is reacted and dried to solidify the liquid composition, thereby providing the film 1a on the substrate 2. The liquid composition is prepared according to the performance required for the film 1a. The liquid composition may be a mixture containing the compounds and additives described below.

[0032] The shape of the hollow particles 11 is not limited to a specific shape. The hollow particles 11 may have a three-dimensional shape such as a substantially spherical shape, or may have an irregular shape.

[0033] The average particle diameter (primary particle diameter) of the hollow particles 11 is not limited to a specific value. The average particle diameter of the hollow particles 11 is, for example, 10 nm to 150 nm. This facilitates uniform dispersion of the hollow particles 11 in the film 1a. The average particle diameter of the hollow particles 11 is preferably 20 nm to 100 nm, more preferably 30 nm to 80 nm. The average particle diameter of the hollow particles 11 may be determined by arithmetically averaging the particle diameters of 50 or more hollow particles 11 observed using a transmission electron microscope (TEM), a SEM, or the like. Note that the particle diameter of each particle refers to the average value of the maximum and minimum diameters. Furthermore, the particle diameter (nominal particle diameter) disclosed by the supplier of the hollow particles or hollow particle sol may be used as the average particle diameter of the hollow particles 11 used, as long as it has little effect on the results and does not result in particularly large differences.

[0034] By including hollow particles 11 in the film 1a, the refractive index of the film 1a can be adjusted to a desired range. This is advantageous, for example, when the film 1a is used as an optically functional film. A low refractive index of the film is advantageous from the viewpoint of reducing surface reflection from a substrate on which the film is provided. The hollow particles 11 have a type of core-shell structure, and contain gas such as air in the core, which easily reduces the refractive index of the film 1a.

[0035] There is no particular limitation on the material forming the shell of the hollow particle 11. The refractive index of the material of the shell of the hollow particle 11 is, for example, 1.15 to 2.70, preferably 1.20 to 2.00, more preferably 1.30 to 1.50, and even more preferably 1.38 to 1.46.

[0036] From the viewpoint of resistance to deformation by external forces, the hollow particles 11 contain an inorganic material. The inorganic material contains at least one selected from the group consisting of silicon oxide, magnesium fluoride, alumina, aluminosilicate, titania, and zirconia. The hollow particles 11 may contain an oxide of at least one element selected from the group consisting of Si, Ti, Zr, Ta, Nb, Nd, La, and Ce.

[0037] The hollow particles 11 preferably contain silicon oxide or magnesium fluoride. In this case, the film 1a is likely to exhibit high anti-reflection performance. The refractive index of silicon oxide is 1.46, and the refractive index of magnesium fluoride is 1.38. The silicon oxide may contain silica (SiO2). When the hollow particles 11 contain silica as silicon oxide, for example, colloidal silica may be added in the preparation of the liquid composition.

[0038] The refractive index of the hollow particles 11 is not limited to a specific value. The refractive index of the hollow particles 11 can be determined by the material forming the shell of the hollow particles 11 and the ratio of the volume of the internal space to the total volume of the hollow particles 11. The refractive index of the hollow particles 11 is, for example, 1.10 to 1.40, preferably 1.20 to 1.35, and more preferably 1.25 to 1.35. For example, among multiple types of hollow particles whose shells are formed from materials with different refractive indices, if the ratio of the volume of the internal space to the total volume of the hollow particles is the same, the refractive index of hollow particles whose shell material has a lower refractive index will be lower than that of hollow particles whose shell material has a higher refractive index. The refractive index of the hollow particles 11 can be measured, for example, by the immersion method (Becke line method). For example, when the hollow particles 11 contain silica, the refractive index of the hollow particles 11 can be determined according to the following steps (i), (ii), and (iii). (i) The dispersion medium of the dispersion liquid of hollow particles 11 is evaporated and dried to obtain a powder. (ii) The powder obtained in (i) is mixed with various standard refractive index liquids having different refractive indices, such as Series A and Series AA manufactured by Gargill. (iii) When the mixed liquid obtained in (ii) becomes transparent, the refractive index of the standard refractive index liquid used is determined to be the refractive index of hollow particles 11.

[0039] The hollow particles 11 may be commercially available or may be prepared by a predetermined method. For example, the hollow particles 11 may be prepared by forming a shell around a core and then removing the core. For example, a shell made of silicon oxide or a shell made of magnesium fluoride may be formed around a polymer core having a particle diameter of several tens of nanometers. The polymer core may then be removed by dissolving in a solvent or by combustion to obtain the hollow particles 11 as hollow silicon oxide particles or hollow magnesium fluoride particles. Alternatively, the hollow particles 11 may be obtained as hollow magnesium fluoride particles by forming a shell made of magnesium fluoride around a silicon oxide core and dissolving the silicon oxide core with an alkali.

[0040] The maximum dimension of the internal space of the hollow particles 11 is not limited to a specific value. The maximum dimension is, for example, 5 to 100 nm, preferably 10 to 70 nm, and more preferably 20 to 50 nm. The hollow particles 11 are preferably monodisperse particles having a coefficient of variation of 0.1 or less.

[0041] The content of the hollow particles 11 in the liquid composition is not limited to a specific value. For example, the ratio r of the mass of the hollow particles 11 to the mass of the solid content of the liquid composition is sh is 0.025 or more. As described above, the film 1a can be produced by solidifying a coating of a liquid composition. The ratio r of the mass of the hollow particles 11 to the mass of the film 1a is fh can be, for example, 0.025 or more. In this case, the refractive index of the film 1a tends to be low within a desired range. In this specification, the mass of the hollow particles 11 means the total mass of the hollow particles 11 contained in the liquid composition or the film 1a.

[0042] Ratio sh and ratio r fh Each of the ratios r is less than 1, for example, 0.9 or less. This makes it easier for the film 1a to have a desired mechanical strength and to be less likely to become brittle. sh and ratio r fh Each of these is preferably 0.1 to 0.85, and more preferably 0.16 to 0.8.

[0043] The silicon oxide contained in the binder 12 of the film 1a has, for example, a Si—O—Si bond. Silicon oxide has a high affinity with silicon oxide such as silica, and when the hollow particles 11 contain silicon oxide such as silica, it is expected that the strength with which the binder 12 binds the hollow particles 11 will be increased.

[0044] As described above, the liquid composition contains a silicon-containing compound, which may be a precursor of the silicon oxide contained in the binder 12. The silicon-containing compound is, for example, a compound such as a hydrolyzable silicon alkoxide, and the silicon-containing compound contained in the liquid composition becomes a compound with a large molecular weight through condensation polymerization after hydrolysis. This promotes solidification of the liquid composition, and the film 1a is formed.

[0045] The hydrolyzable silicon alkoxide compound is, for example, represented by the following formula (C): 1 and R 2 Each of R is an organic group having 1 to 30 carbon atoms. This organic group is, for example, a hydrocarbon group having 1 to 30 carbon atoms or a halogenated hydrocarbon group in which some of the hydrogen atoms in a hydrocarbon group having 1 to 30 carbon atoms have been substituted with halogen atoms. 1 and R 2 may be the same as or different from each other. The hydrolyzable silicon alkoxide compound is 1 and R 2 In formula (C), n=m=0. 3 is an alkyl group having 1 to 10 carbon atoms, n and m are integers of 0 or more, and n+m is 3 or less. 1 n R 2 m Si(OR 3 ) 4-(n+m) Formula (C)

[0046] In formula (C), (OR 3) is an alkoxy group, and the hydrolyzable silicon alkoxide compound represented by formula (C) is an alkoxysilane compound. In this way, an alkoxysilane compound has an alkoxy group in the molecule. By hydrolysis of the alkoxy group, a silanol group (—Si—OH) is formed, and at the same time, an alcohol (R 3 The silanol groups then undergo condensation accompanied by dehydration to form siloxane bonds (-Si-O-Si-). This condensation is repeated to form siloxane polymers with large molecular weights.

[0047] The alkoxysilane compound, which is a silicon-containing compound contained in the liquid composition, is not limited to a specific alkoxysilane compound. Examples of the alkoxysilane compound include tetrafunctional silane compounds (n=m=0) such as tetramethoxysilane (TMOS), tetraethoxysilane (TEOS), and tetraisoproxilane. Other examples of the alkoxysilane compound include β-glycidoxyethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β-glycidoxypropyltrimethoxysilane, β-glycidoxyethylmethyldimethoxysilane, β-glycidoxyethylmethyldiethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylethyldimethoxysilane, γ-glycidoxypropylethyldiethoxysilane, β-glycidoxypropylethyldiethoxysilane, β-glycidoxyethylpropyldimethoxysilane, β-glycidoxypropylethyldiethoxysilane, β-glycidoxypropylethyldiethoxysilane, β-glycidoxyethylpropyldimethoxysilane, β-(3,4 epoxy) Examples of alkoxysilane compounds include trifunctional silane compounds (n + m = 1) such as (cyclohexyl)ethyltriethoxysilane, methyltrimethoxysilane, methyltriethoxysilane (MTES), vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxyethoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane, γ-chloropropyltripoxysilane, γ-chloropropyltriptoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, γ-trifluoropropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, and γ-methacryloxypropylmethyldimethoxysilane. Further examples of alkoxysilane compounds include bifunctional silane compounds (n + m = 2) such as dimethyldimethoxysilane (DMDMS), dimethyldiethoxysilane (DMDES), and dimethyldimethoxysilane.

[0048] The liquid composition may contain, as the silicon-containing compound, a single type of alkoxysilane compound or multiple types of alkoxysilane compounds. The liquid composition may also contain, as the silicon-containing compound, hydrolysates of these alkoxysilane compounds.

[0049] When the liquid composition contains a tetrafunctional alkoxysilane compound or a hydrolyzate of a tetrafunctional alkoxysilane compound represented by the structural formula (C) where n + m = 0, the solid content unit thereof is represented by the general formula SiO2 and is called silica. When the liquid composition contains a trifunctional alkoxysilane compound or a hydrolyzate of a trifunctional alkoxysilane compound represented by the structural formula (C) where n + m = 1, the solid content unit thereof is R 12 SiO 2 / 3 and is called silsesquioxane. 12 is R 1 and R 2 When the liquid composition contains a bifunctional alkoxysilane compound or a hydrolyzate of a bifunctional alkoxysilane compound represented by the structural formula (C) where n+m=2, the solid content unit thereof is R 12 2SiO and is called diorganosiloxane. 12 is R 1 and R 2 The following is a summary.

[0050] The binder 12 of the film 1a preferably contains at least one silicon oxide selected from the group consisting of silica and silsesquioxane as described above. When the binder 12 contains silica, the binder 12 tends to have high density. On the other hand, when the binder 12 contains silsesquioxane, the binder 12 tends to be flexible.

[0051] R 1 or R 2 R may be a chain or cyclic alkyl group having 3 to 30 carbon atoms, and the chain alkyl group may be branched. 1 or R 2may be a fluorinated hydrocarbon group in which some of the hydrogen atoms in the hydrocarbon have been substituted with fluorine atoms.

[0052] The ratio r of the mass of the solid content of the alkoxysilane and the alkoxysilane hydrolysate to the mass of the solid content of the liquid composition sa is not limited to a specific value. sa is, for example, 0.015 to 0.2. In addition, the ratio r of the mass of the solid content of silica and polysilsesquioxane to the mass of the membrane 1a fo The ratio r is, for example, 0.015 to 0.2. sa and ratio r fo When the ratio r is 0.015 or more, it is easy to prevent the hollow particles 11 contained in the film 1a from having insufficient binding strength, which would otherwise result in a decrease in the mechanical strength of the film 1a. sa and ratio r fo When the ratio r is 0.2 or less, the refractive index of the film 1a tends to be low within a desired range. sa and ratio r fo is preferably 0.03 to 0.18, and more preferably 0.05 to 0.15.

[0053] In the liquid composition, the ratio r of the mass of the solid content of the alkoxysilane and the alkoxysilane hydrolysate to the mass of the hollow particles 11 ha is not limited to a specific value. ha is, for example, 0.05 to 0.4. In addition, in the film 1a, the ratio r ho is, for example, 0.05 to 0.4. ha and ratio r ho When the ratio r is 0.05 or more, the refractive index of the film 1a tends to be low within a desired range. ha and ratio r ho When the ratio r is 0.4 or less, it is easy to prevent the hollow particles 11 contained in the film 1a from having insufficient binding strength, which would otherwise result in a decrease in the mechanical strength of the film 1a. ha and ratio r ho is preferably 0.1 to 0.35.

[0054] The water-absorbent resin contained in the liquid composition is not limited to a specific water-absorbent resin. Examples of water-absorbent resins include polyethylene glycol, polyether-based resins, polyurethane resins, starch-based resins, cellulose-based resins, acrylic resins, epoxy-based resins, polyester polyols, hydroxyalkyl cellulose, polyvinyl alcohol resins, polyvinyl pyrrolidone, polyvinyl acetal resins, and polyvinyl acetate. The water-absorbent resin preferably includes at least one selected from the group consisting of hydroxyalkyl cellulose, polyvinyl alcohol resins, polyvinyl pyrrolidone, polyvinyl acetal resins, polyvinyl acetate, epoxy-based resins, and polyurethane resins. More preferably, the water-absorbent resin includes at least one selected from the group consisting of polyvinyl alcohol resins, epoxy-based resins, polyurethane resins, and polyvinyl acetal resins. In this case, the membrane 1a is likely to have the desired water absorption.

[0055] The water-absorbing resin is particularly preferably a polyvinyl acetal resin. The polyvinyl acetal resin can be obtained by acetalizing polyvinyl alcohol through a condensation reaction with an aldehyde. The acetalization of polyvinyl alcohol can be carried out using known methods such as a precipitation method using an aqueous medium in the presence of an acid catalyst or a dissolution method using a solvent such as alcohol. The acetalization can also be carried out in parallel with the saponification of polyvinyl acetate. The degree of acetalization of the polyvinyl acetal resin is, for example, 2 to 40 mol%, and may be 3 to 30 mol%, 5 to 20 mol%, or 5 to 15 mol%. The degree of acetalization can be, for example, 13 When the degree of acetalization of the polyvinyl acetal resin is within the above range, the binder 12 of the film 1a tends to have the desired water absorption and water resistance.

[0056] The average degree of polymerization of polyvinyl alcohol is not limited to a specific value. The average degree of polymerization is, for example, 200 to 4500, preferably 500 to 4500. A high average degree of polymerization is advantageous from the viewpoint of enhancing the water absorption and water resistance of the binder 12 of the film 1a. On the other hand, if the average degree of polymerization is 4500 or less, it is easy to prevent the viscosity of the liquid composition from becoming too high, which would hinder the formation of the film 1a.

[0057] The degree of saponification of polyvinyl alcohol is not limited to a specific value, and the degree of saponification is preferably 75 to 99.8 mol %.

[0058] The aldehyde to be condensed with polyvinyl alcohol is not limited to a specific aldehyde. Examples of aldehydes include aliphatic aldehydes such as formaldehyde, acetaldehyde, butylaldehyde, hexylcarbaldehyde, octylcarbaldehyde, and decylcarbaldehyde. Other examples of aldehydes include aromatic aldehydes, including benzaldehyde, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, other alkyl-substituted benzaldehydes, chlorobenzaldehyde, other halogen-substituted benzaldehydes, substituted benzaldehydes in which hydrogen atoms are replaced by functional groups other than alkyl groups, such as hydroxyl groups, alkoxy groups, amino groups, and cyano groups, naphthaldehyde, and condensed aromatic ring aldehydes such as anthraldehyde.

[0059] When the aldehyde to be condensed with polyvinyl alcohol is an aromatic aldehyde, the aromatic aldehyde has high hydrophobicity, so even if the degree of acetalization of the polyvinyl acetal resin contained in the binder 12 is low, the water resistance of the binder 12 is likely to be high. The use of an aromatic aldehyde is advantageous from the viewpoint of increasing the water absorption of the film 1a while leaving many hydroxyl groups in the film 1a. For this reason, the polyvinyl acetal resin contained in the binder 12 and the liquid composition preferably contains an acetal structure derived from an aromatic aldehyde, more preferably from benzaldehyde.

[0060] The epoxy resin is not limited to a specific epoxy resin. Examples of the epoxy resin include a glycidyl ether epoxy resin, a glycidyl ester epoxy resin, a glycidyl amine epoxy resin, and a cycloaliphatic epoxy resin. The epoxy resin is preferably a cycloaliphatic epoxy resin.

[0061] The polyurethane resin is not limited to a specific polyurethane resin. The polyurethane resin is obtained by polymerization of a polyisocyanate and a polyol. Preferred examples of the polyol include an acrylic polyol and a polyoxyalkylene polyol.

[0062] In the liquid composition, the ratio r of the mass of the water-absorbent resin to the mass of the solid content of the alkoxysilane and the alkoxysilane hydrolysate ar In addition, in the film 1a, the ratio r of the mass of the water-absorbent resin to the mass of silica and silsesquioxane contained in the binder 12 is or is not limited to a specific value. ar and ratio r or is, for example, 1 to 16. ar and ratio r or When the ratio r is 1 or more, the water absorption of the membrane 1a is less likely to become insufficient. ar and ratio r or When the ratio r is 16 or less, the film 1a tends to have a low refractive index within a desired range. ar and ratio r or is preferably 1.5 to 15, and more preferably 1.8 to 14.

[0063] The ratio r of the mass of the water-absorbent resin to the mass of the solid content of the liquid composition sr is not limited to a specific value. In addition, the ratio r of the mass of the water-absorbent resin to the mass of the membrane 1a fr is not limited to a specific value. sr and ratio r fr is, for example, 0.1 or more. In this case, the water absorption of the membrane 1a is unlikely to become insufficient. sr and ratio r fr When the ratio r is large, the refractive index of the film 1a is unlikely to be low. sr and ratio r frThe ratio r is, for example, 0.9 or less. sr and ratio r fr is preferably 0.15 to 0.8, and more preferably 0.16 to 0.78.

[0064] The liquid composition further contains, for example, a solvent, which allows the alkoxysilane, the hydrolyzate of the alkoxysilane, the water-absorbent resin, and the hollow particles 11 to be uniformly dissolved or dispersed in the liquid composition, which is a precursor of the film 1 a.

[0065] The solvent is not limited to a specific solvent. Examples of the solvent include methanol, ethanol, isopropyl alcohol, n-propyl alcohol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, tert-butyl alcohol, acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, ethyl isobutyl ketone, diisobutyl ketone, cyclohexanone, 1,4-dioxane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether acetate, methyl acetate, ethyl acetate, butyl acetate, ethyl lactate, diethylene glycol dimethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, 2-methoxyethanol, and hydrofluoroethers. The liquid composition may contain only one type of solvent or may contain two or more types of solvents.

[0066] The solvent contains, for example, at least one selected from the group consisting of propylene glycol monopropyl ether, propylene glycol monoethyl ether, and propylene glycol monomethyl ether acetate. In this case, when the liquid composition is applied to the surface of the substrate 2, unevenness in the thickness of the coating film is likely to be reduced. As a result, the thickness of the film 1a is likely to be uniform within the surface.

[0067] The liquid composition may contain additives such as modifiers as needed. The liquid composition may contain, for example, a surface modifier. The surface modifier has the property of reducing surface tension, and therefore functions as a leveling agent for the coating film of the liquid composition, and is expected to suppress defects and chipping of the coating film. The surface modifier may remain in the film 1a.

[0068] The modifier is not limited to a specific modifier. Examples of modifiers include silane compounds such as polyether-modified silane compounds, methacrylic group-modified silane compounds, dimethyl group-modified silane compounds, acrylic group-modified silane compounds, and polyester-modified silane compounds. For example, the modifier may be contained in a liquid composition containing one or more compounds.

[0069] When the liquid composition contains a surface modifier, the ratio of the mass of the surface modifier to the mass of the solid content of the liquid composition is, for example, 1 × 10 -3 ~20 x 10 -3 and preferably 2×10 -3 ~10 x 10 -3 is.

[0070] The liquid composition and film 1a may contain an ultraviolet absorber, if necessary. In this case, deterioration of the substrate 2 and film 1a due to ultraviolet rays can be suppressed. The ultraviolet absorber is not limited to a specific ultraviolet absorber. Examples of ultraviolet absorbers include organic compounds such as benzotriazole compounds, benzophenone compounds, hydroxyphenyltriazine compounds, and cyanoacrylate compounds. Examples of benzotriazole compounds include 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and 2-(2'-hydroxy-3',5'-di-t-butylphenyl)benzotriazole. Examples of benzophenone compounds include 2,2',4,4'-tetrahydroxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, and 5,5'-methylenebis(2-hydroxy-4-methoxybenzophenone). Examples of hydroxyphenyltriazine compounds are 2-(2-hydroxy-4-octoxyphenyl)-4,6-bis(2,4-di-t-butylphenyl)-s-triazine, 2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-s-triazine, and 2-(2-hydroxy-4-propoxy-5-methylphenyl)-4,6-bis(2,4-di-t-butylphenyl)-s-triazine. Examples of cyanoacrylate compounds are ethyl-α-cyano-β,β-diphenylacrylate and methyl-2-cyano-3-methyl-3-(p-methoxyphenyl)acrylate. The liquid composition and film 1a may contain only one type of ultraviolet absorber, or may contain two or more types of ultraviolet absorbers.

[0071] The ultraviolet absorber may contain at least one organic dye selected from the group consisting of polymethine compounds, imidazoline compounds, coumarin compounds, naphthalimide compounds, perylene compounds, azo compounds, isoindolinone compounds, quinophthalone compounds, and quinoline compounds. The ultraviolet absorber is preferably an organic compound, and more preferably contains at least one compound selected from the group consisting of benzotriazole compounds, benzophenone compounds, hydroxyphenyltriazine compounds, and cyanoacrylate compounds. The ultraviolet absorber is even more preferably a benzophenone compound. Benzophenone compounds have good solubility in alcohol-based solvents and are easily dispersed uniformly in polyvinyl acetal resins.

[0072] The ultraviolet absorber preferably has a hydroxy group. More preferably, the ultraviolet absorber includes a compound in which two or more hydroxy groups are bonded to one benzene skeleton. In the liquid composition and film 1a, the ratio of the mass of the ultraviolet absorber to the mass of the water-absorbent resin is, for example, 0.001 to 0.5, more preferably 0.01 to 0.4, and even more preferably 0.02 to 0.35.

[0073] The liquid composition and the film 1a may contain an infrared absorber, if necessary. Examples of infrared absorbers include organic infrared absorbers such as polymethine compounds, cyanine compounds, phthalocyanine compounds, naphthalocyanine compounds, naphthoquinone compounds, anthraquinone compounds, dithiol compounds, immonium compounds, diimonium compounds, aminium compounds, pyrylium compounds, cerium compounds, squarylium compounds, and counterion conjugates of benzenedithiol metal complex anions and cyanine dye cations. Other examples of infrared absorbers include inorganic infrared absorbers such as tungsten oxide, tin oxide, indium oxide, magnesium oxide, titanium oxide, chromium oxide, zirconium oxide, nickel oxide, aluminum oxide, zinc oxide, iron oxide, ammonium oxide, lead oxide, bismuth oxide, lanthanum oxide, tungsten oxide, indium tin oxide, and antimony tin oxide.

[0074] The infrared absorber may contain an infrared absorber containing a phosphonic acid component and a copper component. Such an infrared absorber makes it easier for the spectrum of transmitted light through the film 1a to match well with human luminosity. This is advantageous, for example, when the film 1a is used for transmitting light in the visible light range. In particular, by including phenylphosphonic acid and alkylphosphonic acid as the phosphonic acid component, the short-wavelength transmission band to which part of ultraviolet light belongs and the long-wavelength transmission band to which part of infrared light belongs can be easily adjusted to a desirable state from the perspective of matching with human luminosity.

[0075] The liquid composition and the film 1a may contain only one type of infrared absorbing agent, or may contain two or more types of infrared absorbing agents.

[0076] The liquid composition may further contain, for example, water, which may promote hydrolysis of the alkoxysilane that may be contained in the liquid composition.

[0077] The liquid composition may contain, for example, an acid. In this case, the acid can act as a catalyst for the hydrolysis of the alkoxysilane. The acid is not limited to a specific acid. Examples of acids are carboxylic acids such as formic acid, acetic acid, and benzoic acid. These acids have a carboxyl group in their molecules. The atoms contained in these acids are limited to carbon atoms, hydrogen atoms, and oxygen atoms, so unnecessary components are less likely to remain in the film 1a. The acid is preferably formic acid. Formic acid has a simple structure while exhibiting sufficient catalytic action for the hydrolysis of the alkoxysilane.

[0078] When the liquid composition contains formic acid, the concentration of formic acid in the liquid composition is, for example, 0.005% by mass to 0.1% by mass.

[0079] The liquid composition may contain, for example, a crosslinking agent. The film 1a may have a crosslinked structure derived from the crosslinking agent. The crosslinking agent is, for example, at least one compound selected from the group consisting of organic boron compounds, organic titanium compounds, and organic zirconium compounds. When the film 1a has a crosslinked structure, the abrasion resistance, scratch resistance, and water resistance of the film 1a tend to be improved. The crosslinked structure tends to increase the durability of the film 1a without reducing the anti-fogging properties of the film 1a, for example. When the film 1a has a crosslinked structure, the binder 12 contains a metal atom other than the silicon atom of the silicon oxide, and preferably contains a boron atom, a titanium atom, or a zirconium atom. In this specification, silicon atoms and boron atoms are treated as metal atoms.

[0080] The crosslinking agent crosslinks, for example, the water-absorbent resin. When the crosslinking agent is an organic titanium compound, examples of the crosslinking agent include titanium alkoxides, titanium chelate compounds, and titanium acylates. Examples of titanium alkoxides include titanium tetraisopropoxide, titanium tetra-n-butoxide, and titanium tetraoctoxide. Examples of titanium chelate compounds include titanium acetylacetonate, titanium ethyl acetoacetate, titanium octylene glycol, titanium triethanolamine, and titanium lactate. Titanium lactate may be an ammonium salt such as titanium lactate ammonium. An example of a titanium acylate is titanium stearate. A desirable example of the organic titanium compound is a titanium chelate compound, particularly titanium lactate.

[0081] When the water-absorbing resin comprises a polyvinyl acetal resin, an organotitanium compound, particularly titanium lactate, may be included as a cross-linking agent.

[0082] The liquid composition and film 1a may contain glycols such as glycerin or ethylene glycol to enhance anti-fogging properties, as needed, and may also contain other additives such as colorants, antifoaming agents, and preservatives.

[0083] As long as the liquid composition contains hollow particles 11, a silicon-containing compound, and a water-absorbent resin, the preparation method of the liquid composition is not limited to a specific method. The reaction of alkoxysilane, which may be contained as the silicon-containing compound in the liquid composition, may be affected by the working temperature, the ambient temperature, and the humidity. Therefore, the preparation method of the liquid composition may be determined by trial and error by a person skilled in the art depending on the properties desired for the liquid composition or the film 1a.

[0084] As shown in FIG. 1 , for example, the film 1a is provided on a substrate 2. The substrate 2 is a transparent dielectric material including, for example, glass or plastic (resin). "Transparent" means that the substrate 2 has high light transmittance at a specific wavelength. The wavelengths for which the substrate 2 is transparent are not limited to the visible light range, and the substrate 2 is transparent to ultraviolet light, visible light, or infrared light depending on the application. "Transparent" means that the transmittance is 50% or more.

[0085] When the substrate 2 is used in the visible light region, the transmittance of the substrate 2 in the wavelength range of 400 nm to 780 nm is, for example, 60% or more, preferably 80% or more, and more preferably 90% or more.

[0086] As long as the film 1a can exhibit the desired properties, the substrate 2 may have a light scattering function and may have a haze of a predetermined value or less. The substrate 2 may have fine irregularities on its surface, such as a diffraction grating. The shape of the substrate 2 is not limited to a specific shape. The substrate 2 may be a parallel plate, or may have a concave shape, a convex shape, or a shape in which concave and convex shapes are mixed. For example, when the substrate 2 is included in an optical component such as a lens, the shape of the substrate 2 may have various shapes not limited to the shapes exemplified here.

[0087] As long as the film 1 a can exhibit the desired properties, the material of the substrate 2 is not limited to a specific material. The substrate 2 may include, for example, plastic, such as polyethylene terephthalate, polyethylene naphtholate, polycarbonate, polyimide, polyamide, polymethyl methacrylate (acrylic resin), ABS resin, vinyl chloride resin, or cycloolefin polymer.

[0088] The substrate 2 may include glass. The glass is not limited to a specific glass. Examples of the glass include soda-lime glass, borosilicate glass, and alumina silicate glass. The glass may be FK5, BK7, K5, K7, K10, SK4, SK5, SK11, SK14, LAK7, LAK8, F2, F5, or BASF2. The glass may be alkali-free glass, infrared absorbing glass, low thermal expansion glass, high refractive index glass, low dispersion glass, or anomalous dispersion glass.

[0089] The method for producing the film 1a is not limited to a specific method as long as the film 1a can exhibit the desired properties. For example, the film 1a can be provided on the substrate 2 by applying a liquid composition that is a precursor of the film 1a to the surface of the substrate 2, and solidifying the resulting coating by reaction and / or drying.

[0090] There is no particular limitation on the method for applying the liquid composition to the surface of the substrate 2. Examples of the method include dip coating, spin coating, die coating, spray coating, gravure coating, roll coating, and inkjet method.

[0091] Before applying the liquid composition to the surface of the substrate 2, the surface of the substrate 2 to which the liquid composition is to be applied may be cleaned. The method for cleaning the surface of the substrate 2 is not limited to a specific method. Cleaning using a detergent, cleaning using an alkaline cleaning solution or an acid cleaning solution, or cleaning in combination with ultrasound may be appropriately selected depending on the purpose. For example, cleaning that increases the hydrophilicity of the surface of the substrate 2 may be selected, such as ozone cleaning in which the target is exposed to an ozone atmosphere, plasma cleaning in which plasma is irradiated, and ultraviolet cleaning in which ultraviolet rays of a relatively short wavelength are irradiated.

[0092] Heat treatment may be performed to react and / or dry the liquid composition. The environmental temperature of the substrate 2 during the heat treatment is, for example, 50° C. to 150° C., preferably 60° C. to 120° C., and more preferably 80° C. to 110° C. The heat treatment time is, for example, 1 minute to 100 minutes, preferably 3 minutes to 30 minutes, and more preferably 5 minutes to 15 minutes.

[0093] 2, for example, an optical component 3a can be provided that includes a substrate 2 and a film 1a provided on the substrate 2. In the optical component 3a, the substrate 2 can exhibit an optical function. As described above, the film 1a can exhibit antireflection properties, and therefore the film 1a may be provided on a surface of the substrate 2 in a region necessary for the substrate 2 to exhibit its optical function.

[0094] The optical component 3 a is not limited to a specific optical component, and examples of the optical component 3 a include a lens, a filter, a prism, a mirror, a diffraction element such as a diffraction grating, a microlens array, a diffusion element having minute irregularities, an optical fiber, a fiber tip, an optical waveguide, and a protective component such as a cover glass.

[0095] 2, the optical component 3a is a lens. When the optical component 3a has multiple surfaces or interfaces, the film 1a may be provided on all or only some of the surfaces, and the film 1a may be provided on a portion of the optical component 3a that requires anti-reflection and anti-fogging properties.

[0096] The haze of the optical component 3a is not limited to a specific value. The optical component 3a provided with the film 1a has a haze of, for example, 1% or less. As a result, when the optical component 3a is used as a transmissive optical component, the contrast of the focused image or the captured image is less likely to decrease. The haze of the optical component 3a provided with the film 1a is preferably 0.8% or less, and more preferably 0.6% or less. While the haze can be considered a desirable small characteristic, attempting to keep it too small can make it difficult to adjust the thickness of the film 1a to the required thickness, which may require significantly advanced production technology and increase industrial difficulty from different perspectives. Therefore, the lower limit of the haze of an optical component provided with the film 1a is preferably 0.1%.

[0097] The transmission characteristics of the substrate 2 of the optical component 3a are not limited to any particular characteristics. The substrate 2 may have, for example, the transmission characteristics described above. For example, in the transmission spectrum of transmitted light for light incident on the substrate 2 at an incident angle of 0°, the transmittance within the wavelength range of 400 nm to 1200 nm is not limited to any particular value. The transmittance is, for example, 85% or more.

[0098] In the reflection spectrum for light incident on the optical component 3a at an incident angle of 0°, the average reflectance in the wavelength range of 400 nm to 700 nm is not limited to a specific value, and is, for example, 0.2% to 3%.

[0099] As shown in FIG. 3 , an optical device 5a including an optical component 3a can be provided. The optical device 5a is not limited to a specific optical device. Examples of the optical device 5a include a camera lens, a medical lens, a microlens, a lens for optical communication, a camera lens for a smartphone, a rod lens, a lens array, a lens for an in-vehicle camera, a lens for an optical disc, a mirror, a lens module included in a binocular, a telescope, a lens for a periscope, etc., a diffractive optical element, an optical fiber, an optical waveguide, a display, a solar cell, eyeglasses, a windshield, and goggles. The camera lens may be a lens used together with a camera or may be a lens built into the camera. The in-vehicle camera lens can be installed inside or outside a vehicle. The lens module includes, for example, multiple lenses or a lens group housed and integrated in a housing.

[0100] For example, when the optical component is a lens, the optical component is required to have high light transmittance. Therefore, the optical component may include glass or transparent plastic. When such a lens optical component is subjected to a change in environmental temperature, such as when it is brought from a low-temperature environment to a high-temperature environment, the surface of the lens may become cloudy. Because the optical component 3a includes the film 1a, the surface of the optical component 3a is less likely to cloud even when the optical component 3a is subjected to such a change in environmental temperature.

[0101] As shown in FIG. 3 , the optical device 5 a is, for example, a lens module. The lens module includes, for example, a plurality of lenses arranged so as to be coaxial, with their optical axes being substantially collinear, and a housing for holding these lenses and integrating some or all of the lens groups. In the lens module, when focusing, zooming, image stabilization, and other corrections are performed, some of the lens groups may be held and moved inside the housing. The housing may also be referred to as a lens barrel. The lens module may have functions such as, but not limited to, focusing, reflecting, diffusing, collimating, and expanding and / or reducing the beam diameter.

[0102] If the optical device 5a is a lens module, the film 1a may be provided on the inner surface, which is the surface of the lens group integrated in the lens module that does not contact the outside of the optical device 5a. The fogging that occurs on the surface of lenses, etc., is caused by tiny water droplets and can also be caused by condensation. If the lenses included in the lens group are arranged inside a sealed or sealed module housing, the inner surfaces of the lens group are hardly exposed to the outside air, so the moisture that fogging the inner surfaces is almost limited to the moisture contained in the sealed space inside the optical device 5a. The volume of the internal space of the optical device 5a that contacts the inner surfaces of the lens group is usually significantly smaller than the volume of the external space of the optical device 5a. For this reason, it is conceivable that the water absorption required of the film 1a is not very high. Even if the water absorption capacity of the film 1a is not significantly high due to the thickness of the film 1a and the content of the water-absorbent resin in the film 1a, the film 1a may be provided on the inner surface, taking into account the anti-reflection properties of the film 1a and the above-mentioned circumstances regarding the inner surface. In this case, the film 1a may be provided on all or part of the inner surface. The film 1a may be provided on a surface of the lens group that contacts the external space of the optical device 5a. Thus, the optical device 5a includes a housing 4 and a plurality of lenses arranged inside the housing 4, and the plurality of lenses have a plurality of inner surfaces. The film 1a is provided on at least one of the plurality of inner surfaces.

[0103] In the optical device 5a, taking into consideration the water absorption performance required for the film 1a, the space in contact with the inner surface is, for example, 0.01 cm 3 ~10cm 3 The volume of this space is more preferably 0.1 cm 3 ~5cm 3 and more preferably 0.1 cm 3 ~1cm 3 is.

[0104] In the example shown in FIG. 3 , the optical device 5a is a lens module, and a lens group 3g including three single lenses 3a, 3b, and 3c is integrated in a housing 4. FIG. 3 is a diagram for explaining the embodiment of the invention, and the lens module or actual lens module that performs a specific function is omitted in FIG. 3 . The lens group 3g includes lenses having a total of six surfaces, and four surfaces 31a, 31b, 31c, and 31d exist as the inner surfaces. In the optical device 5a, a film 1a may be provided on all or part of the inner surfaces 31a, 31b, 31c, and 31d. Each inner surface can be said to be a surface facing the space between two lenses.

[0105] The film 1a can be applied to various aspects. For example, as shown in FIG. 4 , in an optical component 3e including a multilayer film 15 including a substrate 21 and multiple layers formed on the substrate 21, the film 1a may be the layer farthest from the substrate 21 in the thickness direction of the multilayer film 15. In this case, the portion 22 of the multilayer film 15 other than the film 1a may be a single-layer film made of a uniform material, or may be a multi-layer film containing multiple different types of uniform materials. In this case, the portion 22 may be referred to as an intermediate layer or intermediate film. An optical component including such a multilayer film can have more desirable anti-reflection performance in terms of transmission band or reflectance. In the optical component 3e, the substrate 2 for the film 1a is composed of the substrate 21 and the portion 22.

[0106] The form and manufacturing method of the film or layer included in portion 22 of multilayer film 15 are not limited to a specific form or manufacturing method, as long as the optical component 3e exhibits the required performance. Portion 22 may be a single-layer film or a multi-layer film obtained by a physical film formation method, such as a vapor deposition method, a sputtering method, or an ion plating method. The single-layer film may contain one or more metal oxides selected from metal compounds such as MgF, SiO, Ta, TiO, and AlO. The multi-layer film may be composed of multiple layers containing one or more metal oxides selected from these metal compounds, stacked sequentially or repeatedly.

[0107] At least one layer included in portion 22 may include a film formed by a so-called sol-gel method, which is obtained by solidifying a composition containing an alkoxysilane or an alkoxysilane hydrolysate through reaction and / or drying. In this case, the alkoxysilane may include one or more compounds selected from the compounds exemplified as alkoxysilanes that can be included in the liquid composition described above. This film may include, for example, at least one selected from the group consisting of silica contained in a tetrafunctional silane and a silsesquioxane derived from a trifunctional silane.

[0108] In the optical component 3e, the portion 22 may be, for example, an intermediate film containing at least one selected from the group consisting of silica and silsesquioxane. The refractive index of this intermediate film at a wavelength of 550 nm is, for example, 1.40 to 1.50. This intermediate film does not contain hollow particles, for example. This intermediate film has a thickness of, for example, 80 nm to 300 nm and is provided in contact with the substrate 21. The optical component 3e may also include an antireflection film with a two-layer structure in which the film 1a is provided in contact with the intermediate film.

[0109] Furthermore, in the optical component 3e, the portion 22 may be, for example, an intermediate film in contact with a first film 1a having a thickness of 10 nm to 100 nm and provided in contact with the substrate 21. This intermediate film may, for example, not contain hollow particles, but contain at least one selected from the group consisting of silica and silsesquioxane, and have a thickness of 10 nm to 100 nm. The optical component 3e may also include an antireflection film with a three-layer structure in which a second film 1a having a thickness of 10 nm to 100 nm is provided in contact with the intermediate film. The refractive index of this intermediate film at a wavelength of 550 nm may be, for example, 1.40 to 1.50.

[0110] The present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

[0111] (Reflectance, Refractive Index, and Thickness) Using an Olympus near-infrared microspectrometer USPM-RU-W and objective lens model number USPM-OBL40 (40x magnification), the reflection spectrum obtained by irradiating the optical film with light in the wavelength range of 380 nm to 1050 nm at an angle of incidence of 0° at a diameter of 17.5 μm (nominal value) was measured. The reflection spectrum of the glass substrate on which the optical film was to be formed was also measured in the same manner. Furthermore, the reflectance at each wavelength was obtained from this reflection spectrum. In this specification, unless otherwise specified, the term "reflection spectrum" simply refers to one obtained by measurement using this method and device, and the reflectance refers to a value obtained by observing the reflectance at a wavelength specified in this reflection spectrum.

[0112] The above-mentioned measuring instrument can acquire a reflection spectrum from a measurement area with a minute spot diameter, making it particularly advantageous for measuring the reflection spectrum of small-diameter optical components. Furthermore, when the measurement target is a parallel plate, an illumination method equipped with an annular illumination and an aperture can be used to measure the spectrum of reflected light only from the first surface, which is reflected from the first surface closest to the objective lens of the measuring instrument, and the second surface opposite the first surface and farther from the objective lens. This allows measurement by canceling out the reflected light from the so-called back surface (second surface). Therefore, even if a film 1a or the like is formed only on the first surface of a parallel plate-shaped substrate, the spectrum of reflected light from that surface can be measured. In this specification, the reflection spectrum refers to the spectrum of reflected light only from the first surface.

[0113] Furthermore, from the obtained reflection spectra, the thickness of the film of each example and the refractive index at each wavelength (particularly at a wavelength of 550 nm) were determined by optimization calculation using the software CODE provided by W. Theiss Hardware and Software. Unless otherwise specified, the reflection spectra and reflectance were measured in a room temperature environment maintained at 25°C ± 5°C after leaving the optical film for 24 hours in a humidity-controlled cabinet where the relative humidity was adjusted to 50% ± 2% and the temperature was adjusted to 25°C ± 5°C.

[0114] (Haze) The haze of each optical film was measured using a haze meter HZ-V3 manufactured by Suga Test Instruments Co., Ltd.

[0115] (Average particle diameter of particles) The average particle diameter of the hollow particles contained in the liquid composition and the optical film is the nominal value (used as a typical value or a nominal particle diameter, etc.) published by the supplier of the hollow particles. Alternatively, the cross section of the optical film may be observed at 50,000 times magnification using an SEM to identify hollow particles having a length of 1 μm (1,000 nm) along the film surface and contained in a region corresponding to the entire thickness of the optical film, the diameters of these hollow particles may be measured, and the average value of the diameters of all the identified hollow particles may be used as the average particle diameter of the hollow particles. In this case, the longest length (major axis) and the shortest length (minor axis) of each hollow particle may be measured, and the average value may be used as the diameter of the hollow particle.

[0116] (Arithmetic mean roughness Ra and ten-point mean roughness Rz of optical film JIS ) Using a scanning probe microscope (SPM) (model SPA-400) manufactured by SII Nanotechnology Corporation (currently Hitachi High-Tech Science Corporation), the arithmetic mean roughness Ra and ten-point mean roughness Rz of the optical film were measured in accordance with JIS B 0601-2001. JIS was measured.

[0117] (Liquid Composition) For the liquid composition of each example, a predetermined amount of purified water, alkoxysilane, formic acid solution, and PGME was first added to a screw-top bottle made of borosilicate glass for use in physical and chemical experiments, and the mixture was stirred at room temperature for 3 hours to obtain an alkoxysilane hydrolyzate-containing liquid. The formic acid concentration in the formic acid solution was 1% by mass. Next, hollow particle sol was added to the screw-top bottle containing the alkoxysilane hydrolyzate-containing liquid, and then a surface modifier and a water-absorbent resin were added sequentially, followed by stirring at room temperature for 0.5 hours to prepare the liquid compositions according to Examples 1 to 18. In each example, the amount of each compound added was adjusted so that the ratio of the mass of each compound to the mass of the liquid composition, expressed in [mass%], was as shown in Table 1.

[0118] In each example, formic acid and the surface modifier were added using liquids that had been previously mixed with PGME to adjust the concentration to 1% by mass. In Table 2, TEOS and MTES are SiO2 and CH3SiO2, respectively. 3 / 2The content was calculated based on the mass converted to the solid content represented by the formula (1), and for other components, the mass of each component relative to the total mass of the liquid composition was calculated as parts by mass of each component. The parts by mass of water in Table 2 were calculated based on the mass of the added purified water and the 55% water already contained in the water absorbent resin. In Table 1, the sum of the components does not equal 100 parts by mass because the hollow particle sol, surface modifier, and water absorbent resin contain components such as solvents other than the active ingredient. PGME: Propylene glycol monoethyl ether (manufactured by Lyondell Asia Pacific, Ltd.) TEOS: Tetraethoxysilane (manufactured by Tama Chemicals) MTES: Methyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) Hollow particle sol: Hollow silica fine particle sol Sururia 4110 (manufactured by JGC Catalysts and Chemicals: hollow particle active ingredient 20.5±0.5 mass%, nominal particle diameter 60 nm) Surface modifier: Polyether type surface modifier KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) Water absorbent resin: Polyvinyl alcohol S-LEC KX-5 (manufactured by Sekisui Chemical Co., Ltd., active ingredient 8.3 mass%)

[0119] Table 2 shows the ratio of the mass of the solid content of each component to the mass of the solid content of the liquid composition according to each example, expressed as a percentage. The solid content of each component includes the active ingredients or solid content (including those not removed by evaporation, etc.) contained in each component. These ratios can be estimated as the ratio of the mass of the solid content of each component to the mass of the optical film formed by solidification of the liquid composition.

[0120] (Optical Film) A soda-lime glass substrate having a square shape with sides measuring 50 mm in plan view and a thickness of 1.1 mm was prepared. The substrate was immersed in a 2% by mass pure aqueous solution of Semiclean LGL (manufactured by Yokohama Yushi Co., Ltd.), subjected to ultrasonic cleaning for 3 minutes, and then removed. The substrate was then rinsed with pure water, and then further immersed in pure water and subjected to ultrasonic cleaning for 3 minutes. The removed substrate was then thoroughly dried. The substrate in the examples underwent this series of processes, including cleaning and drying. The reflection spectrum of the glass substrate after cleaning is shown in FIG. 7. In this reflection spectrum, the reflectance was 5% or less in the wavelength range of 400 nm to 700 nm, indicating extremely low absorption in this wavelength range. This suggests that the transmittance of the glass substrate was at least 85% or 90% in the wavelength range of 400 nm to 700 nm.

[0121] The cleaned substrate was fixed to the stage of a spin coater while keeping its surface clean. An appropriate amount of the liquid composition according to each example was taken with a dropper and dropped onto the center of the cleaned substrate. The spin rotation speed was adjusted within the range of 3,000 to 4,000 rotations per minute (rpm) so that the coating thickness would be approximately 60 to 120 nm, and a coating film of the liquid composition was formed.

[0122] Next, the substrates on which coating films of the liquid compositions of Examples 1 to 18 had been formed were placed inside a clean oven while being kept substantially horizontal, and subjected to a heat treatment for 10 minutes at an ambient temperature of 100°C to solidify the liquid compositions, thereby producing optical films of Examples 19 to 36. In other words, the optical films of Examples 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, and 36 were formed from the liquid compositions of Examples 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, and 18, respectively.

[0123] The reflectance spectra of the optical films according to Examples 19 to 36 were measured using the near-infrared microspectrometer. The reflectance spectra of the optical films according to Examples 19, 20, 22, 23, and 24 are shown in FIG. 5 . The reflectance spectra of the optical films according to Examples 29, 30, 31, 32, and 33 are shown in FIG. 6 . Furthermore, for the optical films according to Examples 19 to 36, the refractive index and thickness of the optical film at a wavelength of 550 nm were calculated using the software CODE described above based on the reflectance spectra. Table 3 shows the characteristic values ​​of the reflectance spectra, the refractive index at a wavelength of 550 nm, the thickness of the optical film, and other values ​​for some of the examples.

[0124] Refractive index n of the optical films according to Examples 19 to 36 at a wavelength of 550 nm f , the ratio r of the mass of the water-absorbing resin to the mass of the optical film fr The relationship between the refractive index n and the mass of the optical film is shown in Figure 8. The mass of the optical film was considered to be equal to the mass of the solid content of the corresponding liquid composition. The dashed line in Figure 8 is an approximate straight line for this relationship. f and ratio r fr Using f = 0.3685 × r fr +1.1681. The dashed line in FIG. f = 0.3685 × r fr +1.12 and n f = 0.3685 × r fr +1.21. In the optical films according to Examples 19 to 36, the refractive index n f is the ratio r fr It is suggested that the value is in the following range, which is specified by two functional formulas expressed using: 0.3685×r fr +1.12≦n f ≦0.3685×r fr +1.21

[0125] The haze of the optical film-coated substrates according to Examples 19 to 36, and the arithmetic mean roughness (Ra) and the ten-point mean roughness (Rz JIS The results are shown in Table 3.

[0126] (Evaluation of Anti-Fog Properties) Optical films for evaluating anti-fogging properties according to Examples 19 to 36 were formed in the same manner as the above optical films according to Examples 19 to 36, except that the coating conditions were adjusted so that the film had a thickness of about 200 nm. The optical films for evaluating anti-fogging properties according to Examples 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, and 36 were formed from the liquid compositions according to Examples 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, and 18, respectively.

[0127] The occurrence of fogging in the optical films for evaluating anti-fogging properties according to Examples 19 to 36 was evaluated using the breath test, in which breath was blown onto the optical films at room temperature (25°C), according to the following criteria. The results are shown in Table 3. A: Fogging occurred later than with regular glass, which is the same soda-lime glass as the substrate. B: Fogging occurred slightly later than with regular glass. C: Equivalent to regular glass.

[0128] As shown in Table 3, the anti-fogging properties of the optical films for anti-fogging evaluation according to Examples 19 to 36 were evaluated as "A" or "B," and it can be said that there is no practical problem with the anti-fogging properties of the optical films provided on the inner surface facing the closed or sealed space inside the lens module.

[0129]

[0130]

[0131]

Claims

1. A liquid composition comprising hollow particles, at least one selected from the group consisting of an alkoxysilane and a hydrolyzate of the alkoxysilane, and a water-absorbing resin, wherein the liquid composition can form a film by solidifying, and the film has a refractive index of 1.15 to 1.

65.

2. The liquid composition according to claim 1, wherein the hollow particles contain silica.

3. The liquid composition according to claim 1 or 2, wherein the ratio of the mass of the water-absorbing resin to the solid content mass of the alkoxysilane and the hydrolyzate of the alkoxysilane is 1 to 16.

4. The liquid composition according to any one of claims 1 to 3, wherein the water-absorbing resin contains at least one selected from the group consisting of a polyvinyl alcohol resin, an epoxy resin, a polyurethane resin, and a polyvinyl acetal resin.

5. The liquid composition according to any one of claims 1 to 4, wherein the ratio of the solid content mass of the alkoxysilane and the hydrolyzate of the alkoxysilane to the solid content mass of the liquid composition is 0.015 to 0.

2.

6. The liquid composition according to any one of claims 1 to 5, wherein the ratio of the mass of the hollow particles to the solid content mass of the liquid composition is 0.025 or more.

7. The liquid composition according to any one of claims 1 to 6, wherein the ratio of the mass of the water-absorbing resin to the solid content mass of the liquid composition is 0.1 or more.

8. A film comprising hollow particles, at least one selected from the group consisting of silica and silsesquioxane, and a water-absorbing resin, and having a refractive index of 1.15 to 1.

65.

9. The film according to claim 8, wherein the thickness of the film is 60 nm to 500 nm.

10. The film according to claim 8 or 9, wherein the hollow particles contain silica.

11. The film according to any one of claims 8 to 10, wherein the ratio of the mass of the water-absorbing resin to the mass of the silica and the silsesquioxane is 1 to 16.

12. The film according to any one of claims 8 to 11, wherein the ratio of the mass of the silica and the silsesquioxane to the mass of the film is 0.015 to 0.

2.

13. The film according to any one of claims 8 to 12, wherein the ratio of the mass of the hollow particles to the mass of the film is 0.025 or more.

14. The ratio of the mass of the water-absorbing resin to the mass of the film is 0.1 or more. The film according to any one of claims 8 to 13.

15. An optical component comprising a substrate and a film provided on the substrate, the film including hollow particles, at least one selected from the group consisting of silica and silsesquioxane, and a water-absorbing resin, the film having a refractive index of 1.15 to 1.

65.

16. The ratio of the mass of the water-absorbing resin to the mass of the silica and the silsesquioxane is 1 to 16. The optical component according to claim 15.

17. The ratio of the mass of the water-absorbing resin to the mass of the film is 0.1 or more. The optical component according to claim 15 or 16.

18. Having a haze of 1% or less. The optical component according to any one of claims 15 to 17.

19. In the reflection spectrum of the reflected light with respect to the light incident on the film at an incident angle of 0°, the average reflectance in the wavelength range of 400 nm to 700 nm is 0.2% to 3%. The optical component according to any one of claims 15 to 18.

20. The refractive index n of the film at a wavelength of 550 nm f and the ratio r of the mass of the water-absorbing resin to the mass of the film fr satisfy the condition represented by the following formula (1). The optical component according to any one of claims 15 to 19. 0.3685 × (r fr ) + 1.12 ≤ n f ≤ 0.3685 × (r fr ) + 1.21 Formula (1) 21. The film includes a surface having an arithmetic mean roughness Ra of 5 nm to 50 nm. The optical component according to any one of claims 15 to 20.

22. Further including an intermediate film, the intermediate film including at least one selected from the group consisting of silica and silsesquioxane and having a refractive index of 1.40 to 1.

50. The optical component according to any one of claims 15 to 21.

23. An optical device including the optical component according to any one of claims 15 to 22.

24. An optical device including a housing and a plurality of lenses disposed inside the housing, the plurality of lenses having a plurality of inner surfaces, and the film according to any one of claims 8 to 14 being provided on at least one of the plurality of inner surfaces.

25. The space in contact with the inner surface is 0.01 cm 3 to 10 cm 3 in volume, for the optical device according to claim 24.

26. A method for manufacturing an optical device, including forming the film according to any one of claims 8 to 14 on at least one surface of a first lens and a second lens, and integrating a lens group including the first lens and the second lens in a housing such that the second lens is next to the first lens, wherein the surface on which the film is formed faces the space between the first lens and the second lens.

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