Optical element and imaging device

Abstract

Provided is an optical element that can exhibit an excellent weathering resistance despite having a glass substrate comprising a phosphate glass or a fluorophosphate glass. The optical element is characterized by the disposition, on at least one main surface of a glass substrate comprising a phosphate glass or a fluorophosphate glass, of a weathering-resistant protective film having a monolayer structure that contains the Si atom and in addition at least one selection from the Ti atom, Zr atom, and Al atom, wherein the proportion of the total number of Ti, Zr, and Al atoms in the total number of the Si, Ti, Zr, and Al atoms exceeds 20.0 atomic% and is not more than 75.0 atomic%.

Description

[Technical Field]

[0001] The present invention relates to an optical element and an imaging device. [Background technology]

[0002] In imaging devices using solid-state imaging elements such as CCD or CMOS image sensors mounted in digital still cameras (DSCs) such as compact digital cameras and digital single-lens reflex cameras, an infrared cut filter (IRCF) that transmits visible light and blocks ultraviolet light and near-infrared light is used to reproduce color tones well and obtain clear images (see, for example, Patent Document 1 (JP 2014-148567 A)).

[0003] FIG. 1 is a schematic diagram of a camera module that constitutes a DSC, where FIG. 1(a) is a schematic diagram of a camera module for a compact digital camera mounted on a smartphone or the like, and FIG. 1(b) is a schematic diagram of a camera module for a digital single-lens reflex camera. In the camera module shown in Figure 1(a), of the light transmitted through lens L, ultraviolet and near-infrared light are selectively reflected by an infrared cut filter (IRCF) 1, and only light in the visible light range that matches the human visual sensitivity is selectively introduced into the module and taken into the image sensor IC. Similarly, in the camera module shown in Figure 1(b), of the light transmitted through lens L, ultraviolet and near-infrared light are selectively reflected by an infrared cut filter (IRCF) 1, and then alpha rays are removed by a cover glass CG while preventing the intrusion of dust, and only light in the visible light range that matches the human visual sensitivity is selectively introduced into the module and taken into the image sensor IC.

[0004] An absorbing glass substrate that absorbs ultraviolet and near-infrared light is used as the constituent substrate of the infrared cut filter (IRCF), and an anti-reflection film (AR film) is provided on the underside (light exit surface) of the glass substrate, or an absorbing resin film that absorbs ultraviolet or near-infrared light and an anti-reflection film (AR film) are sequentially provided on the underside (light exit surface) of the glass substrate, thereby effectively reducing ultraviolet and near-infrared light in the incident light while transmitting only light in the visible light range downward with high incidence characteristics. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-148567 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0006] However, the inventors have conducted studies and found that phosphate-based glass, fluorophosphate-based glass, or the like is usually used as a constituent material of the absorbing glass substrate that absorbs the above-mentioned ultraviolet light or near-infrared light, and that these glasses are prone to glass burning under high temperature and high humidity conditions, and that such glass burning changes the optical properties and makes the anti-reflection film, etc., formed on the surface of the glass substrate prone to peeling.

[0007] Under these circumstances, an object of the present invention is to provide an optical element that can exhibit excellent weather resistance despite having a glass substrate made of phosphate-based glass or fluorophosphate-based glass, and to provide an imaging device that includes such an optical element. [Means for solving the problem]

[0008] As a result of intensive research conducted by the present inventors in order to achieve the above-mentioned object, they have found that the above-mentioned technical problems can be solved by an optical element comprising a glass substrate made of phosphate-based glass or fluorophosphate-based glass, and a weather-resistant protective film having a single-layer structure, the weather-resistant protective film containing Si atoms and one or more atoms selected from Ti, Zr, and Al, wherein the proportion of the total number of Ti, Zr, and Al atoms to the total number of Si, Ti, Zr, and Al atoms is more than 20.0 atomic % and not more than 75.0 atomic %, and they have completed the present invention based on this finding.

[0009] That is, the present invention is (1) At least one main surface of a glass substrate made of phosphate glass or fluorophosphate glass is provided with containing, together with Si atoms, one or more atoms selected from Ti atoms, Zr atoms, and Al atoms, The ratio of the total number of Ti atoms, Zr atoms and Al atoms to the total number of Si atoms, Ti atoms, Zr atoms and Al atoms is more than 20.0 atomic % and 75.0 atomic % or less. A weather-resistant protective film having a single layer structure is provided. An optical element characterized by: (2) The optical element according to (1) above, wherein Si atoms and one or more atoms selected from Ti atoms, Zr atoms, and Al atoms constituting the weather-resistant protective film are bonded in a three-dimensional network pattern by chemical bonds between atoms of the same kind or between atoms of different kinds via oxygen atoms. (3) The optical element according to (1) or (2) above, wherein the weather-resistant protective film contains 8.3 to 27.5 atomic % of Si atoms, 6.6 to 28.5 atomic % of one or more atoms selected from Ti atoms, Zr atoms, and Al atoms, and 61.9 to 66.6 atomic % of oxygen atoms. (4) The weather-resistant protective film is (I) one or more silicon compounds selected from alkoxysilanes, alkoxysilane derivatives, and oligomers of polymers of one or more of these; (IIa) an alkoxytitanium, an alkoxytitanium derivative, or an oligomer comprising one or more polymers thereof; (IIb) Olicomers consisting of alkoxyzirconium, alkoxyzirconium derivatives, or polymers of one or more of these, and (IIc) Oligomers of alkoxyaluminum, alkoxyaluminum derivatives, or polymers of one or more of these and one or more polyvalent metal compounds selected from The optical element according to any one of (1) to (3) above, (5) A glass substrate made of phosphate glass or fluorophosphate glass is provided on at least one main surface thereof with a compound represented by the following general formula (i): Si(OR 1 )(OR 2 ) (OR 3 ) (OR 4 ) (i) (However, R 1 , R 2 , R 3 and R 4 are straight-chain or branched-chain hydrocarbon groups having 1 to 10 carbon atoms, and may be the same or different.) and an alkoxysilane represented by the following general formula (iia): Ti(OR 5 )(OR 6 )(OR 7 )(OR 8 ) (iia) (However, R 5 , R 6 , R 7 and R 8 are linear or branched hydrocarbon groups having 1 to 10 carbon atoms, and may be the same or different from each other), and Zr(OR 9 )(OR 10 )(OR 11 )(OR 12 ) (iib) (However, R 9 , R 10 , R 11 and R 12are linear or branched hydrocarbon groups having 1 to 10 carbon atoms, and may be the same or different from each other.) and the following general formula (iic): Al(OR 13 )(OR 14 )(OR 15 ) (iic) (However, R 13 , R 14 and R 15 are straight-chain or branched-chain hydrocarbon groups having 1 to 10 carbon atoms, and may be the same or different.) and a weather-resistant protective film containing a hydrolysis / dehydration condensation product with one or more metal alkoxides selected from the group consisting of The optical element according to any one of (1) to (4) above, (6) When the total content of the alkoxysilane represented by the general formula (i) and one or more metal alkoxides selected from the general formulae (iia) to (iic) is taken as 100.0 mol%, the weather-resistant protective film satisfies the following: It includes a hydrolysis and dehydration condensation product of 25.0 mol % or more and less than 80.0 mol % of an alkoxysilane represented by the general formula (i) and more than 20.0 mol % and 75.0 mol % or less of one or more metal alkoxides selected from the general formulae (iia) to (iic). The optical element according to (5) above, (7) The optical element according to any one of (1) to (6) above, wherein the glass substrate is an absorbing glass substrate that absorbs ultraviolet light or near-infrared light. (8) The optical element according to any one of (1) to (7) above, further comprising a resin film or an anti-reflection film on the weather-resistant protective film. (9) The optical element according to any one of (1) to (7) above, wherein a resin film and an anti-reflection film are further provided in this order on the weather-resistant protective film, or an anti-reflection film and a resin film are further provided in this order. (10) The optical element according to any one of (1) to (9), wherein the optical element is an optical filter. (11) An imaging device comprising, as an optical filter, the optical element according to any one of (1) to (9) above, together with a solid-state imaging element and an imaging lens. This provides: [Effects of the Invention]

[0010] According to the present invention, it is possible to provide an optical element that can exhibit excellent weather resistance despite having a glass substrate made of phosphate-based glass or fluorophosphate-based glass, and it is also possible to provide an imaging device that includes such an optical element. [Brief explanation of the drawings]

[0011] [Figure 1] 1A and 1B are schematic explanatory diagrams of camera modules, where FIG. 1A is a schematic explanatory diagram of a camera module related to a compact digital camera, and FIG. 1B is a schematic explanatory diagram of a camera module related to a digital single-lens reflex camera. [Figure 2] 1A and 1B are schematic explanatory diagrams showing examples of optical elements according to the present invention. [Figure 3] 1A and 1B are schematic explanatory diagrams showing examples of optical elements according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] The optical element according to the present invention has a glass substrate made of phosphate glass or fluorophosphate glass, and at least one of the main surfaces of the glass substrate is provided with: containing, together with Si atoms, one or more atoms selected from Ti atoms, Zr atoms, and Al atoms, The ratio of the total number of Ti atoms, Zr atoms and Al atoms to the total number of Si atoms, Ti atoms, Zr atoms and Al atoms is more than 20.0 atomic % and 75.0 atomic % or less. A weather-resistant protective film having a single layer structure is provided. It is characterized by the following. The optical element according to the present invention will be described below.

[0013] [Glass substrate] The optical element according to the present invention has a glass substrate made of phosphate glass or fluorophosphate glass.

[0014] In the optical element according to the present invention, the glass substrate preferably has a thickness of 0.01 to 1.50 mm, more preferably 0.01 to 0.70 mm, and even more preferably 0.01 to 0.30 mm. When the thickness of the glass substrate is within the above range, it is possible to easily achieve a thin optical element.

[0015] In the optical element according to the present invention, the glass substrate is made of phosphate glass or fluorophosphate glass.

[0016] The phosphate-based glass of the present invention is a glass containing the essential components P and O and other optional components, and particularly preferably contains CuO. The phosphate-based glass containing CuO can more effectively absorb near-infrared light. Examples of other optional components of the phosphate-based glass include Ca, Mg, Sr, Ba, Li, Na, K, and Cs.

[0017] The fluorophosphate glass of the present invention is a glass containing P, O, and F as essential components and other optional components, and one containing CuO is particularly preferred. When the fluorophosphate glass contains CuO, it can absorb near-infrared light more effectively. Examples of other optional components of the fluorophosphate glass include Ca, Mg, Sr, Ba, Li, Na, K, and Cs.

[0018] The phosphate-based glass may include: P2O: more than 50% by mass but not more than 70% by mass Al2O30~40% by mass, BaO 0~40% by mass, CuO 0~40% by mass Preferably, it contains:

[0019] The phosphate-based glass may include: P2O520~60% by mass, Al2O30~10% by mass, BaO 0~10 mass%, CuO 0~10% by mass More preferably, it contains:

[0020] The phosphate-based glass may include: P2O520~60% by mass, Al2O31~10% by mass, BaO 1~10% by mass, CuO 1~10% by mass More preferably, it comprises:

[0021] The fluorophosphate glass may include: P2O: more than 50% by mass but not more than 70% by mass Al2O30~40% by mass, BaO 0~40% by mass, CuO 0~40% by mass and further contains more than 0 mass% and up to 40 mass% of fluoride. Things are preferred.

[0022] The fluorophosphate glass may include: P2O520~60% by mass, Al2O30~10% by mass, BaO 0~10% by mass, CuO 0~10% by mass and further contains 1 to 30 mass% of fluoride. Things are more preferable.

[0023] The fluorophosphate glass may include: P2O520~60% by mass, Al2O31~10% by mass, BaO 1~10% by mass, CuO 1~10% by mass and further contains 2 to 30 mass% of fluoride. Things are even more preferable.

[0024] The fluoride may be one or more selected from MgF2, CaF2, SrF2, and the like.

[0025] In the optical element according to the present invention, the glass substrate is preferably an absorbing glass substrate that absorbs ultraviolet light or near-infrared light. In the present application, an absorbing glass substrate refers to a glass substrate used to absorb only ultraviolet light, only near-infrared light, or both ultraviolet and near-infrared light; specifically, it refers to glass that selectively absorbs only ultraviolet light (wavelength range of 200 to 400 nm), only near-infrared light (wavelength range of 700 to 2500 nm), or both ultraviolet and near-infrared light, and selectively transmits light in the wavelength range of more than 400 nm and less than 700 nm, when irradiated with light containing ultraviolet light (wavelength range of 200 to 400 nm) and visible light (wavelength range of more than 400 nm and 2500 nm or less).

[0026] The optical element according to the present invention is characterized in that a weather-resistant protective film having a single layer structure is provided on at least one main surface of the glass substrate. The weather-resistant protective film may include a film containing, in addition to Si atoms, one or more atoms selected from Ti atoms, Zr atoms, Al atoms, Mg atoms, P atoms, Ca atoms, Y atoms, Hf atoms, Nb atoms, Ta atoms, W atoms, Zn atoms, Ga atoms, In atoms, and La atoms. Of these, the optical element according to the present invention employs a film containing, in addition to Si atoms, one or more atoms selected from Ti atoms, Zr atoms, and Al atoms. In the optical element according to the present invention, the weather-resistant protective film contains, in addition to Si atoms, one or more atoms selected from Ti atoms, Zr atoms, and Al atoms, and may further contain one or more atoms selected from Mg atoms, P atoms, Ca atoms, Y atoms, Hf atoms, Nb atoms, Ta atoms, W atoms, Zn atoms, Ga atoms, In atoms, and La atoms.

[0027] In the optical element according to the present invention, the weather-resistant protective film may include, as will be described later, a film containing a hydrolysis and dehydration condensation product of an oligomer made of an alkoxide of each metal, a derivative thereof, or a polymer of one or more of these. In the optical element according to the present invention, when the weather-resistant protective film contains, in addition to Si atoms, one or more atoms selected from Ti atoms, Zr atoms, and Al atoms, and further contains one or more atoms selected from Mg atoms, P atoms, Ca atoms, Y atoms, Hf atoms, Nb atoms, Ta atoms, W atoms, Zn atoms, Ga atoms, In atoms, and La atoms, the weather-resistant protective film may contain a hydrolysis / dehydration condensation product of a composite metal alkoxide containing multiple metals, such as yttrium aluminum i-propoxide (Y[Al(Oi-C3H7)4]3).

[0028] In the optical element according to the present invention, the weather-resistant protective film has a single layer structure containing Si atoms and at least one atom selected from Ti atoms, Zr atoms and Al atoms. In the present application, the term "single layer structure" refers to a layer structure that is identified as being made of forming materials having the same composition from the measurement image (image contrast) or elemental analysis results obtained when measured using a scanning transmission electron microscope-energy dispersive X-ray spectrometer (STEM-EDX) under the following conditions: <Measurement conditions> Scanning transmission electron microscope: JEOL Ltd. ARM200F Energy dispersive X-ray spectrometer: JED-2300T manufactured by JEOL Ltd. Sample preparation: Focused ion beam processing (FIB) Accelerating voltage: 200 kV Elemental analysis: EDX mapping (resolution: 256 x 256)

[0029] In the optical element according to the present invention, the thickness of the weather-resistant protective film is preferably 1000 nm or less, more preferably 10 to 500 nm, and even more preferably 30 to 300 nm. When the thickness of the weather-resistant protective film is 1000 nm or less, it becomes easier to prevent unevenness from occurring during the formation (heating) of the weather-resistant protective film, and the film surface of the weather-resistant protective film can be easily made uniform. Furthermore, when the thickness of the weather-resistant protective film is 10 nm or more, the weather-resistant protective film tends to exhibit sufficient bonding strength, and the mechanical strength of the optical element can be easily improved.

[0030] In the present application, the thickness of the weather-resistant protective film refers to the arithmetic mean value when the thickness of the weather-resistant protective film is measured at 50 points in a measurement image (image contrast) of the cross section of the optical element obtained by measurement using the above-mentioned STEM-EDX.

[0031] In the optical element according to the present invention, the weather-resistant protective film contains, in addition to Si atoms, one or more atoms selected from Ti atoms, Zr atoms, and Al atoms. The one or more atoms selected from Ti atoms, Zr atoms, and Al atoms contained in the weather-resistant protective film together with Si atoms are preferably Al atoms or Ti atoms, and more preferably Al atoms.

[0032] In the weather-resistant protective film constituting the optical element according to the present invention, the proportion α (atomic %) of the total number of Ti atoms, Zr atoms and Al atoms to the total number of Si atoms, Ti atoms, Zr atoms and Al atoms (total atomic number) is preferably more than 20.0 atomic % and not more than 75.0 atomic %, more preferably 22.5 to 70.0 atomic %, and even more preferably 25.0 to 65.0 atomic %.

[0033] In the present application, the ratio α (atomic %) of the total number of Ti atoms, Zr atoms, and Al atoms to the total number (total atomic number) of Si atoms, Ti atoms, Zr atoms, and Al atoms that constitute the weather-resistant protective film refers to a value calculated by the following method. (1) STEM-EDX measurement of the optical element is performed under the above-mentioned measurement conditions to obtain STEM-EDX lines (EDX ray (K ray) detection intensity lines in the depth direction of each element constituting the optical element). (2) In the region that constitutes the weather-resistant protective film, the integrated EDX ray intensity of Si atoms XSi, the integrated EDX ray intensity of Ti atoms XTi, the integrated EDX ray intensity of Zr atoms XZr, and the integrated EDX ray intensity of Al atoms XAl are determined. (3) The value obtained by multiplying each integrated EDX ray intensity obtained in (2) by the k-factor (a correction coefficient that depends on the accelerating voltage and detection efficiency and varies depending on the atomic number. For convenience, the k-factor of Si atoms will be referred to as KSi, the k-factor of Ti atoms as KTi, the k-factor of Zr atoms as KZr, and the k-factor of Al atoms as KAl) can be considered to correspond to the weight ratio of each constituent element. Therefore, for example, the weight percentage ATi (wt%) of Ti atoms that make up the weather-resistant protective film can be calculated using the following formula.

number

number

number

number

[0034] In the optical element according to the present invention, the proportion of the total number of Si atoms, Ti atoms, Zr atoms, and Al atoms in the total number of metal atoms constituting the weather-resistant protective film is preferably 70.0 to 100.0 atomic %, more preferably 80.0 to 100.0 atomic %, and even more preferably 90.0 to 100.0 atomic %. In the present application, the ratio (atomic %) of the total number of Si atoms, Ti atoms, Zr atoms, and Al atoms to the total number of all metal atoms constituting the weather-resistant protective film also refers to a value calculated in the same manner as the ratio α (atomic %) of the total number of Ti atoms, Zr atoms, and Al atoms to the total number (total number of atoms) of Si atoms, Ti atoms, Zr atoms, and Al atoms constituting the weather-resistant protective film. In the optical element according to the present invention, the metal atoms constituting the weather-resistant protective film preferably include only one or more atoms selected from Ti atoms, Zr atoms and Al atoms, together with Si atoms.

[0035] In the optical element according to the present invention, the Si atoms and one or more atoms selected from Ti atoms, Zr atoms, and Al atoms constituting the weather-resistant protective film are preferably bonded in a three-dimensional network pattern by chemical bonds between the same atoms or between different atoms via oxygen atoms.

[0036] Here, the phrase "atoms of the same kind are chemically bonded via an oxygen atom" means that atoms of the same kind (Si atoms and Si atoms, Ti atoms and Ti atoms, Zr atoms and Zr atoms, or Al atoms and Al atoms) are chemically bonded via an oxygen atom. For example, in the case of Si atoms, this means that adjacent Si atoms form a chemical bond represented by -Si-O-Si- via an oxygen atom.

[0037] Furthermore, the expression "heterogeneous atoms are chemically bonded via an oxygen atom" means that heterogeneous atoms (Si and Ti atoms, Si and Zr atoms, Si and Al atoms, Ti and Zr atoms, Ti and Al atoms, or Zr and Al atoms) are chemically bonded via an oxygen atom. For example, when the heterogeneous atoms are Si and Ti atoms, this means that adjacent Si and Ti atoms form a chemical bond represented by -Si-O-Ti- via an oxygen atom.

[0038] The phrase "Si atoms and one or more atoms selected from Ti atoms, Zr atoms, and Al atoms are bonded in a three-dimensional network pattern by chemical bonds between the same or different atoms via oxygen atoms" means that adjacent metal atoms form chemical bonds via oxygen atoms, and the metal atoms are bonded in an infinite number in a network pattern in the three-dimensional direction. In the optical element according to the present invention, the weather-resistant protective film may contain, as will be described later, a hydrolysis and dehydration condensation product of an alkoxide of each metal, a derivative thereof, or an oligomer formed from a polymer of one or more of these metals. Such a hydrolysis and dehydration condensation product can easily form a structure in which the Si atoms and one or more atoms selected from Ti atoms, Zr atoms, and Al atoms are bonded in a three-dimensional network pattern by chemical bonds via oxygen atoms between atoms of the same kind or between atoms of different kinds.

[0039] In the optical element according to the present invention, the weather-resistant protective film is made up of Si atoms and one or more atoms selected from Ti atoms, Zr atoms, and Al atoms. The state in which these atoms are bonded in a three-dimensional network pattern by chemical bonds between the same atoms or different atoms via oxygen atoms can be confirmed by vibrational spectroscopy (infrared spectroscopy, Raman spectroscopy).

[0040] In the optical element according to the present invention, the weather-resistant protective film contains, as essential components, Si atoms and one or more atoms selected from Ti atoms, Zr atoms and Al atoms. In the optical element according to the present invention, when the weather-resistant protective film is in a state in which multiple atoms of the same type or different types are three-dimensionally bonded together by chemical bonds via oxygen atoms, the weather-resistant protective film preferably contains 8.3 to 27.5 atomic % of Si atoms, more preferably 13.3 to 26.8 atomic %, and even more preferably 16.6 to 26.0 atomic %. In the optical element according to the present invention, the weather-resistant protective film preferably contains one or more atoms selected from Ti atoms, Zr atoms, and Al atoms in an amount of 6.6 to 28.5 atomic %, more preferably 7.5 to 22.2 atomic %, and even more preferably 8.3 to 18.1 atomic %. In the optical element according to the present invention, the weather-resistant protective film preferably contains 61.9 to 66.6 atomic % of oxygen atoms, more preferably 62.9 to 66.6 atomic %, and even more preferably 63.6 to 66.6 atomic %.

[0041] In this application, the content of Si atoms and the content of one or more atoms selected from Ti atoms, Zr atoms, and Al atoms that constitute the weather-resistant protective film refer to values ​​measured by ICP (Inductively Coupled Plasma) spectroscopy. In the present application, the content of oxygen atoms constituting the weather-resistant protective film means a value measured by inorganic elemental analysis.

[0042] In the optical element according to the present invention, the weather-resistant protective film comprises: (I) an oligomer of an alkoxysilane, an alkoxysilane derivative, or a polymer of at least one of these; (IIa) an alkoxytitanium, an alkoxytitanium derivative, or an oligomer comprising one or more polymers thereof; (IIb) Olicomers consisting of alkoxyaluminum, alkoxyaluminum derivatives, or polymers of one or more of these, and (IIc) Oligomers of alkoxyaluminum, alkoxyaluminum derivatives, or polymers of one or more of these It is preferable that the polyisoprene contains a hydrolysis and dehydration condensation product with one or more selected from the following.

[0043] Examples of alkoxysilanes that are used as raw materials for the weather-resistant protective film include one or more selected from tetramethyl silicate, tetraethyl silicate, tetrapropyl silicate, and tetrabutyl silicate. When reactivity is taken into consideration, one or more selected from tetramethyl silicate and tetraethyl silicate are preferred.

[0044] The alkoxysilane derivatives used as raw materials for the weather-resistant protective film are preferably compounds derived from alkoxysilanes in which functional groups other than alkoxy groups have been introduced as some or all of the substituents, and which have functional groups that can react with hydroxyl groups on the surface of the glass substrate, with each other, or with other components that make up the weather-resistant protective film during hydrolysis and dehydration condensation reactions to form bonds. Specific examples of such compounds include the following:

[0045] (The functional group is an alkyl group) Methyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, n-propyltriethoxysilane, n-hexyltriethoxysilane, and the like.

[0046] (The functional group is an aromatic group (phenyl group)) Phenyltrimethoxysilane, phenyltriethoxysilane, etc.

[0047] (The functional group is a vinyl group) Vinyltrimethoxysilane, vinyltriethoxysilane, etc.

[0048] (The functional group is an epoxy group) 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and the like.

[0049] (The functional group is a styryl group) p-Styryltrimethoxysilane, etc.

[0050] (The functional group is a methacrylic group) 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, etc.

[0051] (The functional group is an acrylic group) 3-acryloxypropyltrimethoxysilane, etc.

[0052] (The functional group is an amino group) 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, and the like.

[0053] (The functional group is a ureido group) Tris-(trimethoxysilylpropyl) isocyanurate, etc.

[0054] (The functional group is a mercapto group) 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and the like.

[0055] (The functional group is an isocyanate group) 3-isocyanatepropyltriethoxysilane, tetraisocyanatesilane, monomethyltriisocyanatesilane, etc.

[0056] (functional group is halogen) Silicon tetrachloride, etc.

[0057] Examples of oligomers made from one or more polymers selected from alkoxysilanes and alkoxysilane derivatives that serve as raw materials for the weather-resistant protective film include oligomers made from a polymer of a monomer made from one or more of the above-mentioned alkoxysilanes, oligomers made from a polymer of a monomer made from one or more of the above-mentioned alkoxysilane derivatives, and oligomers made from a polymer of a monomer made from one or more of the above-mentioned alkoxysilanes and a monomer made from one or more of the above-mentioned alkoxysilane derivatives.

[0058] The alkoxytitanium used as a raw material for the weather-resistant protective film can be one or more selected from titanium(IV) tetramethoxide, titanium(IV) tetraethoxide, titanium(IV) tetra-iso-propoxide, titanium(IV) tetra-n-butoxide, etc.

[0059] The alkoxytitanium derivatives used as raw materials for the weather-resistant protective film are preferably compounds derived from alkoxytitanium in which functional groups other than alkoxy groups have been introduced as some or all of the substituents, and which have functional groups that can react with hydroxyl groups on the surface of the glass substrate, with each other, or with other components that make up the weather-resistant protective film during hydrolysis and dehydration condensation reactions to form bonds.

[0060] Specific examples of the alkoxy titanium derivative include one or more selected from titanium diisopropoxybis(acetylacetonate), titanium diisopropoxybis(ethylacetoacetate), titanium octylene glycolate, titanium tetraacetylacetonate, titanium diisopropoxybis(triethanolaminate), titanyl chloride, titanium tetrachloride, and the like.

[0061] Examples of oligomers comprising one or more polymers selected from alkoxytitaniums and alkoxytitanium derivatives, which are raw materials for the weather-resistant protective film, include oligomers comprising a polymer of monomers comprising one or more of the above-mentioned alkoxytitaniums, oligomers comprising a polymer of monomers comprising one or more of the above-mentioned alkoxytitanium derivatives, and oligomers comprising a polymer of a monomer comprising one or more of the above-mentioned alkoxytitaniums and a monomer comprising one or more of the above-mentioned alkoxytitanium derivatives.

[0062] The alkoxyzirconium used as a raw material for the weather-resistant protective film can be one or more selected from zirconium(IV) tetramethoxide, zirconium(IV) tetraethoxide, zirconium(IV) tetra-n-propoxide, zirconium(IV) tetra-i-propoxide, zirconium(IV) tetra-n-butoxide, etc.

[0063] The alkoxyzirconium derivative used as a raw material for the weather-resistant protective film is preferably a compound derived from alkoxyzirconium in which functional groups other than alkoxy groups have been introduced as some or all of the substituents, and which has functional groups that can react with hydroxyl groups on the surface of the glass substrate, with each other, or with other components that make up the weather-resistant protective film during hydrolysis and dehydration condensation reactions to form bonds.

[0064] Specific examples of the alkoxyzirconium derivative include one or more selected from zirconium tributoxymonoacetylacetonate, zirconium dibutoxybis(ethylacetoacetate), (isopropoxy)tris(dipivaloylmethanato)zirconium, and the like.

[0065] Examples of oligomers made from a polymer of one or more types selected from alkoxyzirconium and alkoxyzirconium derivatives, which are raw materials for the weather-resistant protective film, include oligomers made from a polymer of monomers made from one or more of the above-mentioned alkoxyzirconium types, oligomers made from a polymer of monomers made from one or more of the above-mentioned alkoxyzirconium derivatives, and oligomers made from a polymer of a monomer made from one or more of the above-mentioned alkoxyzirconium types and a monomer made from one or more of the above-mentioned alkoxyzirconium derivatives.

[0066] The alkoxyaluminum that is the raw material for the weather-resistant protective film can be one or more selected from aluminum(III) trimethoxide, aluminum(III) triethoxide, aluminum(III) tri-n-propoxide, aluminum tri-i-propoxide, aluminum(III) tri-sec-butoxide, aluminum(III) di-i-propylate mono-sec-butylate, and the like.

[0067] The alkoxyaluminum derivatives used as raw materials for the weather-resistant protective film are preferably compounds derived from alkoxyaluminum in which functional groups other than alkoxy groups have been introduced as some or all of the substituents, and which contain functional groups that can react with hydroxyl groups on the surface of the glass substrate, with each other, or with other components that make up the weather-resistant protective film during hydrolysis and dehydration condensation reactions to form bonds.

[0068] Specific examples of the alkoxyaluminum derivative include one or more selected from aluminum ethyl acetoacetate diisopropylate, aluminum alkyl acetoacetate diisopropylate, aluminum tris(acetylacetonate), aluminum tris(ethyl acetoacetate), aluminum monoacetylacetonate bis(ethyl acetoacetate), cyclic aluminum oxide stearate, and cyclic aluminum oxide octylate.

[0069] Examples of oligomers comprising a polymer of one or more types selected from alkoxyaluminums and alkoxyaluminum derivatives, which are used as raw materials for the weather-resistant protective film, include oligomers comprising a polymer of monomers comprising one or more of the above-mentioned alkoxyaluminums, oligomers comprising a polymer of monomers comprising one or more of the above-mentioned alkoxyaluminum derivatives, and oligomers comprising a polymer of monomers comprising one or more of the above-mentioned alkoxyaluminums and monomers comprising one or more of the above-mentioned alkoxyaluminum derivatives.

[0070] In the optical element according to the present invention, the weather-resistant protective film is preferably a reaction product of 25.0 mol % or more and less than 80.0 mol % of the silicon compound (I) with more than 20.0 mol % and 75.0 mol % or less of one or more metal alkoxides selected from the general formulae (IIa) to (IIc), when the total content of the silicon compound (I) and one or more polyvalent metal compounds selected from the general formulae (IIa) to (IIc) is taken as 100.0 mol %, and It is more preferable that the silicon compound (I) is a reaction product of 30.0 mol % to 77.5 mol % with 22.5 mol % to 70.0 mol % of one or more metal alkoxides selected from the general formulas (IIa) to (IIc) above, and it is even more preferable that the silicon compound (I) is a reaction product of 35.0 mol % to 75.0 mol % with 25.0 mol % to 65.0 mol % of one or more metal alkoxides selected from the general formulas (IIa) to (IIc) above.

[0071] More specifically, the optical element according to the present invention comprises: A glass substrate made of phosphate glass or fluorophosphate glass is provided on at least one main surface thereof with a compound represented by the following general formula (i): Si(OR 1 )(OR 2 ) (OR 3 ) (OR 4 ) (i) (However, R 1 , R 2 , R 3 and R 4are straight-chain or branched-chain hydrocarbon groups having 1 to 10 carbon atoms, and may be the same or different.) and an alkoxysilane represented by the following general formula (iia): Ti(OR 5 )(OR 6 )(OR 7 )(OR 8 ) (iia) (However, R 5 , R 6 , R 7 and R 8 are linear or branched hydrocarbon groups having 1 to 10 carbon atoms, and may be the same or different from each other), and Zr(OR 9 )(OR 10 )(OR 11 )(OR 12 ) (iib) (However, R 9 , R 10 , R 11 and R 12 are linear or branched hydrocarbon groups having 1 to 10 carbon atoms, and may be the same or different from each other.) and the following general formula (iic): Al(OR 13 )(OR 14 )(OR 15 ) (iic) (However, R 13 , R 14 and R 15 are straight-chain or branched-chain hydrocarbon groups having 1 to 10 carbon atoms, and may be the same or different.) Examples of the metal alkoxide include those provided with a weather-resistant protective film containing a hydrolysis / dehydration condensation product with one or more metal alkoxides selected from the group consisting of the following:

[0072] General formula (i) Si(OR 1 )(OR 2 ) (OR 3 ) (OR 4 ) (i) In the compound represented by the formula 1 , R2 , R 3 and R 4 is a linear or branched hydrocarbon group having 1 to 10 carbon atoms, preferably a linear or branched hydrocarbon group having 1 to 4 carbon atoms, and more preferably a linear or branched hydrocarbon group having 1 to 3 carbon atoms.

[0073] R 1 , R 2 , R 3 and R 4 Specific examples of the alkyl group include those selected from linear, branched, and cyclic hydrocarbon groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl groups. R 1 , R 2 , R 3 and R 4 may be the same or different from each other.

[0074] In the optical element according to the present invention, R 1 , R 2 , R 3 and R 4 When the number of carbon atoms is within the above range, it becomes easier to maintain a suitable reaction rate between the alkoxysilane and the metal alkoxide, and it becomes easier to carry out a more uniform reaction.

[0075] General formula (iia)Ti(OR) 5 )(OR 6 )(OR 7 )(OR 8 ), titanium alkoxides represented by the general formula (iib) Zr(OR 9 )(OR 10 )(OR 11 )(OR 12 ) and zirconium alkoxides represented by the general formula (iic)Al(OR 13 )(OR 14 )(OR 15 In the aluminum alkoxide represented by the formula 5 ~R 15 (R 5 , R6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 and R 15 ) is a linear or branched hydrocarbon group having 1 to 10 carbon atoms, preferably a linear or branched hydrocarbon group having 2 to 9 carbon atoms, and more preferably a linear or branched hydrocarbon group having 3 to 8 carbon atoms.

[0076] R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 or R 15 Specific examples of the alkyl group include those selected from linear, branched, and cyclic hydrocarbon groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl groups. R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 and R 15 may be the same as or different from each other.

[0077] In the optical element according to the present invention, R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 and R 15When the number of carbon atoms is 2 or more, the stability of the metal alkoxide against moisture can be effectively improved, and when the number of carbon atoms is 9 or less, an increase in the viscosity of the metal alkoxide can be suppressed, and the handleability can be effectively improved.

[0078] General formula (i) Si(OR 1 )(OR 2 ) (OR 3 ) (OR 4 ) (i) The alkoxysilane represented by the formula (I) can easily produce a compound having a reactive silanol group (Si—OH group) by hydrolysis. When the alkoxysilane represented by the general formula (i) is partially hydrolyzed, the reaction proceeds, for example, as follows. Si(OR 1 )(OR 2 ) (OR 3 ) (OR 4 ) + HO → Si(OR 1 )(OR 2 ) (OR 3 )OH+R 4 OH Furthermore, when all of the alkoxy groups of the alkoxysilane represented by the general formula (i) are hydrolyzed, the reaction proceeds as follows to produce silanol Si(OH)4. Si(OR 1 )(OR 2 ) (OR 3 ) (OR 4 )+4H2O → Si(OH)4+R 1 OH+R 2 OH+R 3 OH+R 4 OH

[0079] General formula (iia)Ti(OR) 5 )(OR 6 )(OR 7 )(OR 8 ), titanium alkoxides represented by the general formula (iib) Zr(OR 9 )(OR 10 )(OR 11)(OR 12 ) and zirconium alkoxides represented by the general formula (iic)Al(OR 13 )(OR 14 )(OR 15 ) also easily produces a compound having a hydroxyl group by hydrolysis.

[0080] Then, by subjecting a hydrolyzate of an alkoxysilane represented by the general formula (i) above to a dehydration condensation reaction with a hydrolyzate of one or more metal alkoxides selected from the group consisting of a titanium alkoxide represented by the general formula (iia) above, a zirconium alkoxide represented by the general formula (iib) above, and an aluminum alkoxide represented by the general formula (iic) above, at least some of these components bond to each other, or the hydrolyzates of the alkoxysilane or the metal alkoxides bond to each other, forming a weather-resistant protective film. Furthermore, when the dehydration condensation reaction is carried out on a glass substrate, at least a portion of the hydrolyzates of the components reacts with the hydroxyl groups on the surface of the glass substrate, thereby being able to bond firmly to the glass substrate.

[0081] In the optical element according to the present invention, the weather-resistant protective film preferably contains a hydrolysis / dehydration condensate of 25.0 mol % or more and less than 80.0 mol % of the alkoxysilane represented by the general formula (i) (or a partial hydrolyzate thereof) and more than 20.0 mol % and 75.0 mol % or less of one or more metal alkoxides selected from the general formulas (iia) to (iic), where the total content of the alkoxysilane represented by the general formula (i) and one or more metal alkoxides selected from the general formulas (iia) to (iic) is taken as 100.0 mol %, and More preferably, the alkoxysilane (or partial hydrolysate thereof) represented by the general formula (i) above comprises a hydrolysis / dehydration condensation product of 30.0 mol % to 77.5 mol % of an alkoxysilane (or partial hydrolysate thereof) represented by the general formula (i) above with 22.5 mol % to 70.0 mol % of one or more metal alkoxides selected from the general formulas (iia) to (iic) above, and even more preferably, the alkoxysilane (or partial hydrolysate thereof) represented by the general formula (i) above comprises a hydrolysis / dehydration condensation product of 35.0 mol % to 75.0 mol % of an alkoxysilane (or partial hydrolysate thereof) represented by the general formula (i) above with 25.0 mol % to 65.0 mol % of one or more metal alkoxides selected from the general formulas (iia) to (iic) above.

[0082] In the optical element of the present invention, the mixing ratio of the alkoxysilane (or partial hydrolyzate thereof) represented by the general formula (i) above and one or more metal alkoxides selected from the general formulae (iia) to (iic) above is each within the above range, so that a weather-resistant protective film exhibiting the desired properties can be easily formed.

[0083] In the optical element according to the present invention, the weather-resistant protective film is formed by partially hydrolyzing the alkoxysilane represented by the general formula (i) (Si(OR 1 )(OR 2 ) (OR 3 ) a hydrolysis / dehydration condensation product of a partial hydrolyzate (represented by, for example, OH) and one or more metal alkoxides selected from the general formulae (iia) to (iic) above. As described above, the alkoxysilanes represented by the general formula (i) and the metal alkoxides represented by the general formulas (iia) to (iic) undergo hydrolysis in the presence of water to produce silanol Si(OH)4 or the corresponding metal hydroxide. Here, the metal alkoxides represented by the general formulas (iia) to (iic) (alkoxides of Ti, Zr, or Al) are significantly more reactive with water than the alkoxysilanes represented by the general formula (i). In the presence of water, they immediately produce metal hydroxides derived from the metal alkoxides represented by the general formulas (iia) to (iic), and the subsequent polycondensation reaction easily produces precipitates, making it difficult to induce homogeneous hydrolysis and polymerization reactions. In particular, when attempting to form a weather-resistant protective film using a coating liquid containing a larger amount of metal alkoxides (alkoxides of Ti, Zr, and Al) represented by the above general formulas (iia) to (iic) compared to alkoxysilanes represented by the above general formula (i), it is difficult to form a homogeneous coating liquid or coating film (weather-resistant protective film) due to the difference in reactivity. Therefore, the alkoxysilane represented by the general formula (i) was partially hydrolyzed in advance (Si(OR 1 )(OR 2 ) (OR 3 A homogeneous coating solution is formed by mixing a partial hydrolyzate (represented by, for example, OH) with one or more metal alkoxides selected from the general formulae (iia) to (iic) above, and then the coating solution is subjected to hydrolysis and dehydration condensation, whereby homogeneous hydrolysis and dehydration condensation reactions can be easily carried out. As a result of the progression of such a homogeneous reaction, not only do hydrolysates of alkoxysilanes represented by the general formula (i) bond together through a dehydration condensation reaction, or hydrolysates of metal alkoxides represented by the general formulas (iia) to (iic) bond together through a dehydration condensation reaction, but also the hydrolysate of alkoxysilane represented by the general formula (i) undergo a dehydration condensation reaction with the hydrolysate of one or more metal alkoxides selected from the compounds represented by the general formulas (iia) to (iic), and at least some of these components bond together to form bonds such as Si-O-Al bonds, Si-O-Ti bonds, and Si-O-Zr bonds, thereby making it possible to easily form the desired weather-resistant protective film.

[0084] In the optical element according to the present invention, it is preferable that the alkoxysilane represented by the general formula (i) (or a partial hydrolyzate thereof) and one or more metal alkoxides selected from the general formulae (iia) to (iic) are stirred for a predetermined period of time in the presence of a catalyst and a suitable solvent to form a mixed liquid (coating liquid).

[0085] In the optical element according to the present invention, the catalyst may be one or more acids selected from hydrochloric acid, nitric acid, acetic acid, etc., or one or more bases selected from ammonia, sodium hydroxide, etc., in order to promote the sol-gel reaction (hydrolysis reaction, polycondensation reaction).

[0086] In the optical element according to the present invention, the solvent is not particularly limited as long as it is a solvent that can ultimately form a homogeneous coating liquid. The solvent may be one or more selected from alcohols such as methanol, ethanol, n-propanol, iso-propanol, and n-butanol, and alkoxy alcohols such as 2-methoxyethanol and 2-ethoxyethanol.

[0087] In the optical element of the present invention, when the alkoxysilane (or partial hydrolyzate thereof) represented by the general formula (i) is mixed with one or more metal alkoxides selected from the general formulae (iia) to (iic), a solvent or a stabilizer for the metal alkoxide may be used. Examples of the stabilizer include one or more selected from β-diketones such as acetylacetone and ethyl acetoacetate, alkanolamines such as monoethanolamine, diethanolamine and triethanolamine, glycols such as ethylene glycol, propylene glycol and diethylene glycol, and the like.

[0088] In the optical element of the present invention, the alkoxysilane represented by the general formula (i) (or a partial hydrolyzate thereof) and one or more metal alkoxides selected from the general formulae (iia) to (iic) are mixed preferably at a temperature of 0 to 200°C, more preferably at a temperature of 10 to 175°C, and even more preferably at a temperature of 15 to 150°C.

[0089] In the optical element of the present invention, the alkoxysilane (or partial hydrolyzate thereof) represented by the general formula (i) above and one or more metal alkoxides selected from the general formulae (iia) to (iic) above are preferably stirred and mixed for 1 minute to 24 hours to form a mixed solution, more preferably stirred and mixed for 1 minute to 12 hours to form a mixed solution, and even more preferably stirred and mixed for 1 minute to 6 minutes to form a mixed solution.

[0090] The alkoxysilane represented by the general formula (i) (or a partial hydrolyzate thereof) and one or more metal alkoxides selected from the general formulae (iia) to (iic) are usually subjected to a hydrolysis and dehydration condensation reaction in the coexistence of the catalyst and solvent used at the time of mixing.

[0091] In the above hydrolysis and dehydration condensation reaction, it is preferable to use a mixed liquid containing the catalyst and solvent used when mixing the alkoxysilane represented by the general formula (i) (or a partial hydrolyzate thereof) with one or more metal alkoxides selected from the general formulae (iia) to (iic) as a coating liquid (weather-resistant protective film-forming liquid).

[0092] That is, it is preferable that a desired amount of a coating liquid (weather-resistant protective film-forming liquid) made from the above-mentioned mixture is applied to at least one main surface of a glass substrate made of phosphate glass or fluorophosphate glass, and then the resulting substrate is heated (baked) at a predetermined temperature for a certain period of time, thereby causing a dehydration condensation reaction, dealcoholization condensation, or the like between a metal element M (Si, Ti, Zr, Al, etc.) in the coating liquid (weather-resistant protective film-forming liquid) and a constituent element M' (a semimetallic or semiconductor element or metal element such as P, Si, Ge, As, Se, Sn, Sb, Te, Bi, etc.) in the glass substrate to form a metalloxane bond M-M and / or a MO-M' bond.

[0093] The method for applying the coating liquid is not particularly limited, and can be appropriately selected from spin coating (spin method), nozzle flow method, spray method, dipping method, roll method, brush coating, and the like.

[0094] The heating temperature when the desired amount of the coating liquid is applied to at least one main surface of the glass substrate and then heated is not particularly limited as long as it is equal to or higher than the temperature at which the solvent constituting the coating liquid volatilizes and equal to or lower than the glass transition point of the glass substrate, and is, for example, 100 to 500°C. After applying a desired amount of the coating liquid to at least one main surface of the glass substrate, the heating time is preferably 1 minute to 24 hours, more preferably 3 minutes to 12 hours, and even more preferably 5 minutes to 6 hours.

[0095] After applying a desired amount of the coating liquid to at least one main surface of a glass substrate, the higher the heating temperature when heating, the easier it becomes to form a weather-resistant protective film that has an excellent effect of improving weather resistance. However, for example, heating at a temperature exceeding the glass transition temperature of the glass substrate makes the glass more likely to soften. Furthermore, the longer the heating time during the hydrolysis and dehydration condensation reaction, the easier it is to form a weather-resistant protective film that has an excellent effect of improving weather resistance, but if the heating time is too long, it becomes difficult to carry out an efficient heat treatment.

[0096] It is believed that the hydrolysis and dehydration condensation product obtained by the above reaction not only bonds the alkoxysilane represented by the general formula (i) above or one or more metal alkoxides selected from the general formulae (iia) to (iic) above to each other, but also forms a coating film that is firmly bonded to the glass substrate, and that such a coating film functions as a protective film (weather-resistant protective film) that can highly inhibit burning of the glass substrate even under high temperature and high humidity conditions.

[0097] When an SiO2 film is formed on a glass substrate made of phosphate glass or fluorophosphate glass by hydrolysis and dehydration condensation polymerization of an alkoxysilane (or its partial hydrolyzate) represented by the above general formula (i), an Si-OP bond is formed between the SiO2 film and the glass substrate. Although SiO2 films are inherently highly weather-resistant, the Si-OP bond formed between them and the glass substrate has poor water resistance and is easily hydrolyzed in the presence of water to be converted into Si-OH, which easily loses its bonding strength with the glass substrate. On the other hand, when a metal oxide film is formed on a glass substrate made of phosphate glass or fluorophosphate glass by hydrolysis and dehydration condensation polymerization of a metal alkoxide represented by any of the general formulae (iia) to (iic), a Ti-OP bond, a Zr-OP bond, or an Al-OP bond is formed between the metal oxide film and the glass substrate. These bonds have high water resistance and are less susceptible to hydrolysis, so that the bond with the glass substrate can be easily maintained. For this reason, it is believed that a weather-resistant protective film with excellent weather resistance can be easily formed by combining an alkoxysilane (or a partial hydrolyzate thereof) represented by the above general formula (i) with one or more metal alkoxides selected from the above general formulas (iia) to (iic) and subjecting this to hydrolysis and dehydration condensation reaction.

[0098] The metal alkoxide to be combined with the alkoxysilane (or partial hydrolyzate thereof) represented by the above general formula (i) is preferably an alkoxyaluminum represented by the above general formula (iic). The phosphorus atoms (P) that make up phosphate glass or fluorophosphate glass have a structure bonded to three bridging oxygen atoms (-O-) and one non-bridging oxygen atom (=O), as shown below.Of these, the non-bridging oxygen atoms (=O) do not form a glass mesh structure, making the glass structure looser, and therefore it is said to have low resistance to water. [ka] On the other hand, in phosphate-based glasses or fluorophosphate-based glasses, Al takes a tetra- or hexa-coordinated structure, and of these, Al in the tetra-coordinated structure has the effect of transforming the non-bridging oxygen (=O) of P into bridging oxygen (-O-), so that all oxygen atoms bonded to P become bridging oxygen (-O-), forming a dense glass network structure, which strengthens the glass structure and is thought to improve water resistance in particular. [ka]

[0099] In the optical element according to the present invention, the thickness of the weather-resistant protective film is preferably 1 nm to 5 μm, more preferably 10 nm to 2 μm, and even more preferably 20 nm to 1 μm. In this application, the thickness of the weather-resistant protective film refers to a value measured using a spectroscopic ellipsometer (M-20000V-Te manufactured by J.A. Woollam) for thicknesses of 1 μm or less, and a stylus-type ultra-precision roughness and film thickness measuring instrument (Dektak 6M manufactured by Veeco) for thicknesses of more than 1 μm.

[0100] The optical element according to the present invention comprises a glass substrate made of phosphate glass or fluorophosphate glass, and a weather-resistant protective film having a single layer structure provided on at least one main surface of the glass substrate. That is, examples of the optical element according to the present invention include: (1) As shown in FIG. 2(a), an optical element 1 is formed by providing a weather-resistant protective film P on one main surface of a glass substrate G made of phosphate glass or fluorophosphate glass, (2) As shown in FIG. 2(b), an optical element 1 is formed by providing weather-resistant protective films P, P on both main surfaces of a glass substrate G made of phosphate glass or fluorophosphate glass. Examples include:

[0101] Furthermore, an example of the optical element according to the present invention is one in which a resin film or an anti-reflection film is further provided on the weather-resistant protective film.

[0102] in particular, (3) As shown in FIG. 3(a), an optical element 1 includes a glass substrate G made of phosphate glass or fluorophosphate glass, a weather-resistant protective film P provided on one main surface thereof, and an anti-reflection film AR further provided on the weather-resistant protective film P. (4) As shown in FIG. 3(b), an example of an optical element 1 is one in which a weather-resistant protective film P is provided on one main surface of a glass substrate G made of phosphate-based glass or fluorophosphate-based glass, and a resin film R is further provided on the weather-resistant protective film P.

[0103] Furthermore, examples of the optical element according to the present invention include an optical element in which a resin film and an anti-reflection film are further provided in this order on the weather-resistant protective film, or an optical element in which an anti-reflection film and a resin film are further provided in this order.

[0104] in particular, (5) As illustrated in FIG. 3(c), an optical element 1 includes a glass substrate G made of phosphate glass or fluorophosphate glass, a weather-resistant protective film P provided on one main surface thereof, and a resin film R and an anti-reflection film AR further provided in this order on the weather-resistant protective film P; (6) As illustrated in FIG. 3(d), an optical element 1 is provided in which a weather-resistant protective film P is provided on one main surface of a glass substrate G made of phosphate-based glass or fluorophosphate-based glass, and an anti-reflection film AR and a resin film R are further provided in this order on the weather-resistant protective film P. Examples include:

[0105] In each optical element 1 shown in FIGS. 2 and 3, it is preferable that the upper main surface of the glass substrate P shown in each figure is the light incident surface when disposed, and the lower main surface of the glass substrate P is the light exit surface when disposed.

[0106] In the optical element 1 shown in FIGS. 3(a) to 3(d), the upper main surface of the glass substrate G (the main surface opposite to the side on which the weather-resistant protective film P is provided) is provided with: (7) (As illustrated in Figures 3(a) to 3(d)) No film may be formed, (8) A weather-resistant protective film P may be further provided, (9) A resin film R or a weather-resistant protective film AR may be further provided via a weather-resistant protective film P or without a weather-resistant protective film P, (10) A resin film R and an anti-reflection film AR may be further provided in this order with or without a weather-resistant protective film P interposed therebetween; (11) An anti-reflection film AR and a resin film R may be further provided in this order, with or without a weather-resistant protective film P interposed therebetween.

[0107] In each of the above-described aspects, examples of the resin film include an absorptive resin film that absorbs ultraviolet light or near-infrared light, a reflection-amplifying film, a protective film for preventing glass from burning, a strengthening film for improving the strength of glass, and a water-repellent film. Examples of the absorptive resin film that absorbs ultraviolet or near-infrared light include those containing a near-infrared absorbing dye and a transparent resin, and those in which the near-infrared absorbing dye is uniformly dissolved or dispersed in the transparent resin are preferred.

[0108] As the near-infrared absorbing dye constituting the absorbing resin film, conventionally known dyes can be used, and one or more selected from cyanine dyes, polymethine dyes, squarylium dyes, porphyrin dyes, metal dithiol complex dyes, phthalocyanine dyes, diimonium dyes, and inorganic oxide particles are preferred, and one or more selected from squarylium dyes, cyanine dyes, and phthalocyanine dyes are more preferred.

[0109] The resin constituting the resin film can be any conventionally known transparent resin, and examples thereof include one or more selected from acrylic resins, epoxy resins, ene-thiol resins, polycarbonate resins, polyether resins, polyarylate resins, polysulfone resins, polyethersulfone resins, polyparaphenylene resins, polyarylene ether phosphine oxide resins, polyimide resins, polyamideimide resins, polyolefin resins, cyclic olefin resins, and polyester resins.

[0110] As the transparent resin, from the viewpoints of transparency, solubility of the near-infrared absorbing dye in the transparent resin, and heat resistance, those with a high glass transition point (Tg) are preferred. Specifically, one or more types selected from polyester resin, polycarbonate resin, polyethersulfone resin, polyarylate resin, polyimide resin, and epoxy resin are preferred, and one or more types selected from polyester resin and polyimide resin are more preferred. The polyester resin is preferably at least one selected from polyethylene terephthalate resin and polyethylene naphthalate resin.

[0111] In addition to the near-infrared absorbing dye and transparent resin, the resin film may further contain optional components such as a color correction dye, a leveling agent, an antistatic agent, a heat stabilizer, a light stabilizer, an antioxidant, a dispersant, a flame retardant, a lubricant, and a plasticizer, as long as the effects of the present invention are not impaired.

[0112] The resin film can be formed, for example, by dissolving or dispersing a pigment, a transparent resin, and further optional ingredients in a solvent to prepare a resin film-forming liquid, which is then applied, dried, and, if necessary, cured.

[0113] The resin film forming liquid may contain a known surfactant such as a cationic, anionic or nonionic surfactant.

[0114] The resin film-forming liquid can be applied by one or more coating methods selected from dip coating, cast coating, spray coating, spin coating, nozzle flow coating, roll coating, and the like.

[0115] The resin film can be formed by applying the resin film-forming liquid onto a substrate and then drying it.

[0116] In each of the above-described embodiments, the antireflection film may be one or more selected from the group consisting of a single-layer film using a low refractive index material such as MgF, a multilayer film using SiO or the like as a low refractive index material and TiO or the like as a high refractive index material, and a porous film made of SiO fine particles and a binder.

[0117] The anti-reflection film can be formed by any method selected from gas phase methods such as vapor deposition, sputtering, and CVD, and liquid phase methods such as dip coating, cast coating, spray coating, spin coating, nozzle flow coating, and roll coating.

[0118] Examples of the optical element according to the present invention include optical filters such as infrared cut filters (IRCF), as well as lenses, prisms, diffraction gratings, substrates, etc. that constitute various optical devices.

[0119] According to the present invention, it is possible to provide an optical element that can exhibit excellent weather resistance despite having a glass substrate made of phosphate glass or fluorophosphate glass.

[0120] Next, an imaging device according to the present invention will be described. An imaging device according to the present invention is characterized by having an optical element according to the present invention as an optical filter, in addition to a solid-state imaging element and an imaging lens. Examples of solid-state imaging devices include image sensors such as a CCD (Charge-Coupled Device) sensor and a CMOS (Complementary Metal Oxide Semiconductor) sensor.

[0121] An example of the configuration of an imaging device according to the present invention is a camera module as shown in FIG. FIG. 1(a) is a schematic diagram of a camera module for a compact digital camera mounted on a smartphone or the like. The camera module shown in FIG. 1(a) has one (or an integer n greater than or equal to 1) lens L (or lenses L1...Ln), an optical filter 1 made of an optical element according to the present invention, and an image sensor IC. Also, Figure 1(b) is a schematic diagram of a camera module for a digital single-lens reflex camera, and the camera module shown in Figure 1(b) has a lens L, an optical filter 1 made of an optical element according to the present invention, a cover glass CG, and an image sensor IC.

[0122] According to the present invention, it is possible to provide an imaging device having, as an optical filter, an optical element that can exhibit excellent weather resistance despite having a glass substrate made of phosphate glass or fluorophosphate glass. [Example]

[0123] The present invention will be further explained below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0124] Example 1 1. Preparation of Coating Solution (1) 4.2 g of a 2.0 N (mol / L) HCl aqueous solution, 10.4 g of 2-propanol, and 17.8 g of 2-methoxyethanol were weighed into a container and mixed in a sealed state. (2) 24.4 g of tetraethyl orthosilicate (Si(OC2H5)4) was added to the container, and the mixture was mixed for 30 minutes at room temperature in a sealed state. (3) 38.5 g of aluminum (III) tri-sec-butoxide (Al(OC4H9)3) was further added to the vessel, and the mixture was heated under reflux for 1.5 hours. After that, heating was stopped and the mixture was cooled to approximately room temperature. (4) A mixed solution of 21.1 g of 2.0 N HCl aqueous solution and 194.0 g of 2-methoxyethanol was added to the container with stirring, and the mixture was mixed for 10 minutes at room temperature in a sealed state to obtain a transparent homogeneous coating liquid (coating liquid composition). The resulting coating solution was equivalent to a mixture of 42.9 mol % of tetraethyl orthosilicate and 57.1 mol % of aluminum (III) tri-sec-butoxide, where the total amount of tetraethyl orthosilicate and aluminum (III) tri-sec-butoxide added was taken as 100 mol %. Furthermore, the solids concentration of the obtained coating solution, i.e., the total content of tetraethyl orthosilicate and aluminum(III) tri-sec-butoxide in the coating solution when converted to SiO2 and Al2O3, respectively, was 5 wt%.

[0125] 2. Formation of coating film (1) The coating solution obtained in 1. was applied to one main surface of an absorbent glass substrate (CM500 manufactured by HOYA Corporation, thickness 0.59 mm) made of phosphate glass using a spin coater at a concentration of 10 μL / cm 2 The glass substrate on which the coating liquid had been applied was then placed on a hot plate heated to 135°C, heated for 3 minutes, and then allowed to cool naturally. (2) Then, the coating liquid is applied at 10 μL / cm to the main surface opposite to the main surface to which the coating liquid is applied. 2 The glass substrate on which the coating liquid was applied was then placed on a hot plate heated to 200° C. and heated for 10 minutes. (3) Thereafter, the coating liquid was applied to both main surfaces of the heat-treated absorbent glass substrate, which was then heat-treated in a muffle furnace at 280° C. for 10 minutes. The heat treatments (1) to (3) described above caused dehydration condensation between hydroxyl groups on the surface of the glass substrate and hydroxyl groups of components constituting the coating solution, or between hydroxyl groups of components constituting the coating solution themselves, thereby producing a glass substrate (optical filter 1) having a protective film with a single-layer structure on each of the two main surfaces. In the protective film, the proportion of Al atoms in the total number of Al atoms and Si atoms is 57.1 atomic %, and the proportion of Si atoms in the total number of Al atoms and Si atoms is 42.9 atomic %. In addition, in the above protective film, when the Al atoms and Si atoms are converted to Al2O3 and SiO2, respectively, the proportion of Al2O3 in the total amount of Al2O3 and SiO2 is 40.0 mol%, and the proportion of SiO2 in the total amount of Al2O3 and SiO2 is 60.0 mol%.

[0126] Example 2 1. Preparation of Coating Solution (1) 3.1 g of 0.5 N (mol / L) HCl aqueous solution, 10.4 g of 2-propanol, and 13.2 g of 2-methoxyethanol were weighed into a container and mixed in a sealed state. (2) 36.0 g of tetraethyl orthosilicate (Si(OC2H5)4) was added to the container, and the mixture was mixed for 30 minutes at room temperature in a sealed state. (3) 19.6 g of titanium (IV) tetra-n-butoxide (Ti(OC4H9)4) was further added to the container, and the mixture was mixed at room temperature for 30 minutes in a sealed state. (4) A mixed solution of 30.1 g of 0.5 N HCl aqueous solution, 82.8 g of 2-propanol, and 104.8 g of 2-methoxyethanol was added to the container under stirring, and mixed at room temperature in a sealed state for 30 minutes to obtain a transparent, homogeneous coating liquid (coating liquid composition). The resulting coating solution corresponds to a mixture of 75.0 mol % of tetraethyl orthosilicate and 25.0 mol % of titanium(IV) tetra-n-butoxide, where the total amount of tetraethyl orthosilicate and titanium(IV) tetra-n-butoxide added is 100 mol %. Furthermore, the solids concentration of the obtained coating solution, i.e., the total content of tetraethyl orthosilicate and titanium(IV) tetra-n-butoxide in the coating solution when converted to SiO2 and TiO2, respectively, was 5 wt%.

[0127] 2. Formation of coating film Using the obtained coating liquid, a glass substrate (optical filter 2) having a protective film of a single layer structure on each of the two main surfaces of a glass substrate made of phosphate-based glass (CM500 manufactured by HOYA Corporation, thickness 0.59 mm) was produced in the same manner as in Example 1. In the protective film, the proportion of Ti atoms in the total number of Ti atoms and Si atoms was 25.0 atomic %, and the proportion of Si atoms in the total number of Ti atoms and Si atoms was 75.0 atomic %. Furthermore, in the above protective film, when the Ti atoms and Si atoms were converted to TiO2 and SiO2, respectively, the proportion of TiO2 in the total amount of TiO2 and SiO2 was 25.0 mol%, and the proportion of SiO2 in the total amount of TiO2 and SiO2 was 75.0 mol%.

[0128] Example 3 1. Preparation of Coating Solution (1) 4.8 g of a 1.0 N (mol / L) aqueous HCl solution and 20.2 g of 2-methoxyethanol were weighed into a container and mixed in a sealed container. (2) 27.7 g of tetraethyl orthosilicate (Si(OC2H5)4) was added to the container, and the mixture was mixed for 30 minutes at room temperature in a sealed state. (3) 25.7 g of an 85% n-butanol solution of zirconium (IV) tetra-n-butoxide (Zr(OC4H9)4) was further added to the container, and the mixture was mixed at room temperature for 30 minutes in a sealed state. (4) A mixed solution of 22.6 g of 1.0 N HCl aqueous solution and 199.0 g of 2-methoxyethanol was added to the container with stirring, and mixed for 30 minutes in a sealed container at room temperature to obtain a transparent, homogeneous coating liquid (coating liquid composition). The resulting coating solution corresponds to a mixture of 70.0 mol % of tetraethyl orthosilicate and 30.0 mol % of zirconium (IV) tetra-n-butoxide, where the total amount of tetraethyl orthosilicate and zirconium (IV) tetra-n-butoxide added is taken as 100 mol %. Furthermore, the solids concentration of the obtained coating solution, i.e., the total content of tetraethyl orthosilicate and zirconium(IV) tetra-n-butoxide in the coating solution when converted to SiO2 and ZrO2, respectively, was 5 wt%.

[0129] 2. Formation of coating film Using the obtained coating liquid, a glass substrate (optical filter 3) having a protective film of a single layer structure on each of the two main surfaces of a glass substrate made of phosphate-based glass (CM500 manufactured by HOYA Corporation, thickness 0.59 mm) was produced in the same manner as in Example 1. In the protective film, the proportion of Zr atoms in the total number of Zr atoms and Si atoms is 30.0 atomic %, and the proportion of Si atoms in the total number of Zr atoms and Si atoms is 70.0 atomic %. In addition, in the above protective film, when zirconium atoms and Si atoms are converted to ZrO2 and SiO2, respectively, the proportion of ZrO2 in the total amount of ZrO2 and SiO2 is 30.0 mol%, and the proportion of SiO2 in the total amount of ZrO2 and SiO2 is 70.0 mol%.

[0130] Example 4 1. Preparation of Coating Solution A transparent, homogeneous coating liquid (coating liquid composition) was obtained in the same manner as in Example 1, except that in "1. Preparation of coating liquid" (2) of Example 1, 36.0 g of tetraethyl orthosilicate (Si(OC2H5)4) was replaced with 21.6 g of tetraethyl orthosilicate (Si(OC2H5)4) and 12.3 g of methyltriethoxysilane (CH3Si(OC2H5)3). The resulting coating solution was equivalent to a mixture of 75.0 mol % of tetraethyl orthosilicate and methyltriethoxysilane in total and 25.0 mol % of titanium(IV) tetra-n-butoxide, where the total amount of the added tetraethyl orthosilicate, methyltriethoxysilane, and titanium(IV) tetra-n-butoxide was taken as 100 mol %. Furthermore, the solids concentration of the obtained coating solution, i.e., the total content of tetraethyl orthosilicate, methyltriethoxysilane, and titanium(IV) tetra-n-butoxide in the coating solution when converted to SiO2 and TiO2, was 5 wt%.

[0131] 2. Formation of coating film Using the obtained coating liquid, a glass substrate (optical filter 4) having a protective film of a single layer structure on each of the two main surfaces of a glass substrate made of phosphate-based glass (CM500 manufactured by HOYA Corporation, thickness 0.59 mm) was produced in the same manner as in Example 1. In the protective film, the proportion of Ti atoms in the total number of Ti atoms and Si atoms is 25.0 atomic %, and the proportion of Si atoms in the total number of Ti atoms and Si atoms is 75.0 atomic %. Furthermore, in the above protective film, when Ti atoms and Si atoms are converted to TiO2 and SiO2, respectively, the proportion of TiO2 in the total amount of TiO2 and SiO2 is 25.0 mol%, and the proportion of SiO2 in the total amount of TiO2 and SiO2 is 75.0 mol%.

[0132] Example 5 1. Preparation of Coating Solution A transparent, homogeneous coating liquid (coating liquid composition) was obtained in the same manner as in Example 1, except that in "1. Preparation of coating liquid" (3) of Example 1, 14.0 g of a tetramer of titanium (IV) tetra-n-butoxide (Ti(OC4H9)4) was used instead of 19.6 g of titanium (IV) tetra-n-butoxide (Ti(OC4H9)4). The obtained coating solution corresponds to a mixture of 75.0 mol % of tetraethyl orthosilicate and 25.0 mol % of the tetramer of titanium (IV) tetra-n-butoxide, where the total amount of the added tetraethyl orthosilicate and the tetramer of titanium (IV) tetra-n-butoxide is 100 mol %. Furthermore, the solid concentration of the obtained coating solution, i.e., the total content of tetraethyl orthosilicate and tetramer of titanium(IV) tetra-n-butoxide in the coating solution when converted to SiO2 and TiO2, respectively, was 5 wt%.

[0133] 2. Formation of coating film Using the obtained coating liquid, a glass substrate (optical filter 5) having a protective film of a single layer structure on each of the two main surfaces of a glass substrate made of phosphate-based glass (CM500 manufactured by HOYA Corporation, thickness 0.59 mm) was produced in the same manner as in Example 1. In the protective film, the proportion of Ti atoms in the total number of Ti atoms and Si atoms is 25.0 atomic %, and the proportion of Si atoms in the total number of Ti atoms and Si atoms is 75.0 atomic %. Furthermore, in the above protective film, when Ti atoms and Si atoms are converted to TiO2 and SiO2, respectively, the proportion of TiO2 in the total amount of TiO2 and SiO2 is 25.0 mol%, and the proportion of SiO2 in the total amount of TiO2 and SiO2 is 75.0 mol%.

[0134] Example 6 1. Preparation of Coating Solution A transparent, homogeneous coating liquid (coating liquid composition) was obtained in the same manner as in Example 1, except that in "1. Preparation of coating liquid" (2) of Example 1, 30.2 g of tetraethyl orthosilicate was used instead of 36.0 g of tetraethyl orthosilicate, and in "1. Preparation of coating liquid" (3) of Example 1, 10.6 g of titanium (IV) tetra-n-butoxide (Ti(OC4H9)4) and 14.0 g of an 85% n-butanol solution of zirconium (IV) tetra-n-butoxide were used instead of 19.6 g of titanium (IV) tetra-n-butoxide (Ti(OC4H9)4). The resulting coating solution corresponds to a mixture of 70.0 mol % of tetraethyl orthosilicate, 15.0 mol % of titanium (IV) tetra-n-butoxide, and 15.0 mol % of zirconium (IV) tetra-n-butoxide, when the total amount of tetraethyl orthosilicate, titanium (IV) tetra-n-butoxide, and zirconium (IV) tetra-n-butoxide added is taken as 100 mol %. Furthermore, the solids concentration of the obtained coating solution, that is, the total content of tetraethyl orthosilicate, titanium(IV) tetra-n-butoxide, and zirconium(IV) tetra-n-butoxide in the coating solution when converted to SiO2, TiO2, and Zirconium(IV) tetra-n-butoxide in the coating solution, was 5 wt%.

[0135] 2. Formation of coating film Using the obtained coating liquid, a glass substrate (optical filter 6) having a protective film of a single layer structure on each of the two main surfaces of a glass substrate made of phosphate-based glass (CM500 manufactured by HOYA Corporation, thickness 0.59 mm) was produced in the same manner as in Example 1. In the protective film, the proportion of Ti atoms in the total number of Ti atoms, Zr atoms, and Si atoms is 15.0 atomic %, the proportion of Zr atoms in the total number of Ti atoms, Zr atoms, and Si atoms is 15.0 atomic %, and the proportion of Si atoms in the total number of Ti atoms, Zr atoms, and Si atoms is 70.0 atomic %. Furthermore, in the above protective film, when Ti atoms, Zr atoms, and Si atoms are converted to TiO2, ZrO2, and SiO2, respectively, the proportion of TiO2 in the total amount of TiO2, ZrO2, and SiO2 is 15.0 mol%, the proportion of ZrO2 in the total amount of TiO2, ZrO2, and SiO2 is 15.0 mol%, and the proportion of SiO2 in the total amount of TiO2, ZrO2, and SiO2 is 70.0 mol%.

[0136] Example 7 1. Preparation of Coating Solution A transparent, homogeneous coating liquid (coating liquid composition) was obtained in the same manner as in Example 1, except that in "1. Preparation of coating liquid" (2) of Example 1, 27.6 g of tetraethyl orthosilicate was used instead of 36.0 g of tetraethyl orthosilicate, and in "1. Preparation of coating liquid" (3) of Example 1, 19.6 g of titanium (IV) tetra-n-butoxide (Ti(OC4H9)4) was used instead of 30.0 g of titanium (IV) tetra-n-butoxide (Ti(OC4H9)4). The resulting coating solution corresponds to a mixture of 60.0 mol % of tetraethyl orthosilicate and 40.0 mol % of titanium(IV) tetra-n-butoxide, where the total amount of tetraethyl orthosilicate and titanium(IV) tetra-n-butoxide added is 100 mol %. In addition, the solids concentration of the obtained coating solution, i.e., the total content of tetraethyl orthosilicate and titanium(IV) tetra-n-butoxide in the coating solution when converted to SiO2 and TiO2, respectively, was 5 wt%.

[0137] 2. Formation of coating film Using the obtained coating liquid, a glass substrate (optical filter 7) having a protective film of a single layer structure on each of the two main surfaces of a glass substrate made of phosphate-based glass (CM500 manufactured by HOYA Corporation, thickness 0.59 mm) was produced in the same manner as in Example 1. In the protective film, the proportion of Ti atoms in the total number of Ti atoms and Si atoms is 40.0 atomic %, and the proportion of Si atoms in the total number of Ti atoms and Si atoms is 60.0 atomic %. Furthermore, in the above protective film, when Ti atoms and Si atoms are converted to TiO2 and SiO2, respectively, the proportion of TiO2 in the total amount of TiO2 and SiO2 is 40.0 mol%, and the proportion of SiO2 in the total amount of TiO2 and SiO2 is 60.0 mol%.

[0138] Example 8 1. Preparation of Coating Solution A transparent, homogeneous coating liquid (coating liquid composition) was obtained in the same manner as in Example 1, except that in "1. Preparation of coating liquid" (2) of Example 1, 22.3 g of tetraethyl orthosilicate was used instead of 36.0 g of tetraethyl orthosilicate, and in "1. Preparation of coating liquid" (3) of Example 1, 19.6 g of titanium (IV) tetra-n-butoxide (Ti(OC4H9)4) was used instead of 36.5 g of titanium (IV) tetra-n-butoxide (Ti(OC4H9)4). The resulting coating solution corresponds to a mixture of 50.0 mol % of tetraethyl orthosilicate and 50.0 mol % of titanium(IV) tetra-n-butoxide, where the total amount of tetraethyl orthosilicate and titanium(IV) tetra-n-butoxide added is 100 mol %. In addition, the solids concentration of the obtained coating solution, i.e., the total content of tetraethyl orthosilicate and titanium(IV) tetra-n-butoxide in the coating solution when converted to SiO2 and TiO2, respectively, was 5 wt%.

[0139] 2. Formation of coating film Using the obtained coating liquid, a glass substrate (optical filter 8) having a protective film of a single layer structure on each of the two main surfaces of a glass substrate made of phosphate-based glass (CM500 manufactured by HOYA Corporation, thickness 0.59 mm) was produced in the same manner as in Example 1. In the protective film, the proportion of Ti atoms in the total number of Ti atoms and Si atoms is 50.0 atomic %, and the proportion of Si atoms in the total number of Ti atoms and Si atoms is 50.0 atomic %. Furthermore, in the above protective film, when Ti atoms and Si atoms are converted to TiO2 and SiO2, respectively, the proportion of TiO2 in the total amount of TiO2 and SiO2 is 50.0 mol%, and the proportion of SiO2 in the total amount of TiO2 and SiO2 is 50.0 mol%.

[0140] Example 9 1. Preparation of Coating Solution A transparent, homogeneous coating liquid (coating liquid composition) was obtained in the same manner as in Example 2, except that in "1. Preparation of coating liquid" (2) of Example 2, 17.0 g of tetraethyl orthosilicate was used instead of 27.7 g of tetraethyl orthosilicate, and in "1. Preparation of coating liquid" (3) of Example 2, 36.9 g of an 85% butanol solution of zirconium (IV) tetra-n-butoxide was used instead of 25.7 g of an 85% butanol solution of zirconium (IV) tetra-n-butoxide. The obtained coating solution corresponds to a mixture of 50.0 mol % of tetraethyl orthosilicate and 50.0 mol % of zirconium (IV) tetra-n-butoxide, where the total amount of tetraethyl orthosilicate and zirconium (IV) tetra-n-butoxide added is 100 mol %. Furthermore, the solids concentration of the obtained coating solution, i.e., the total content of tetraethyl orthosilicate and zirconium(IV) tetra-n-butoxide in the coating solution when converted to SiO2 and ZrO2, respectively, was 5 wt%.

[0141] 2. Formation of coating film Using the obtained coating liquid, a glass substrate (optical filter 9) having a protective film of a single layer structure on each of the two main surfaces of a glass substrate made of phosphate-based glass (CM500 manufactured by HOYA Corporation, thickness 0.59 mm) was produced in the same manner as in Example 1. In the protective film, the proportion of Zr atoms in the total number of Zr atoms and Si atoms is 50.0 atomic %, and the proportion of Si atoms in the total number of Zr atoms and Si atoms is 50.0 atomic %. Furthermore, in the above protective film, when Zr atoms and Si atoms are converted to ZrO2 and SiO2, respectively, the proportion of ZrO2 in the total amount of ZrO2 and SiO2 is 50.0 mol%, and the proportion of SiO2 in the total amount of ZrO2 and SiO2 is 50.0 mol%.

[0142] Example 10 1. Preparation of Coating Solution A transparent, homogeneous coating liquid (coating liquid composition) was obtained in the same manner as in Example 3, except that in "1. Preparation of coating liquid" (2) of Example 3, 36.5 g of tetraethyl orthosilicate was used instead of 36.0 g of tetraethyl orthosilicate, and in "1. Preparation of coating liquid" (3) of Example 3, 21.6 g of aluminum (III) tri-sec-butoxide was used instead of 38.5 g of aluminum (III) tri-sec-butoxide. The resulting coating solution was equivalent to a mixture of 66.7 mol % of tetraethyl orthosilicate and 33.3 mol % of aluminum (III) tri-sec-butoxide, where the total amount of tetraethyl orthosilicate and aluminum (III) tri-sec-butoxide added was taken as 100 mol %. The solids concentration of the obtained coating solution, i.e., the total content of tetraethyl orthosilicate and aluminum(III) tri-sec-butoxide in the coating solution when converted to SiO2 and Al2O3, respectively, was 5 wt%.

[0143] 2. Formation of coating film Using the obtained coating liquid, a glass substrate (optical filter 10) having a protective film of a single layer structure on each of the two main surfaces of a glass substrate made of phosphate-based glass (CM500 manufactured by HOYA Corporation, thickness 0.59 mm) was produced in the same manner as in Example 1. In the protective film, the proportion of Al atoms in the total number of Al atoms and Si atoms is 33.3 atomic %, and the proportion of Si atoms in the total number of Al atoms and Si atoms is 66.7 atomic %. In addition, in the above protective film, when the Al atoms and Si atoms are converted to Al2O3 and SiO2, respectively, the proportion of Al2O3 in the total amount of Al2O3 and SiO2 is 20.0 mol%, and the proportion of SiO2 in the total amount of Al2O3 and SiO2 is 80.0 mol%.

[0144] (Comparative Example 1) In this example, the glass substrate made of phosphate glass used in Example 1 (CM500 manufactured by HOYA Corporation, thickness 0.59 mm) was used as a comparative optical filter 1 without forming a coating film.

[0145] (Comparative Example 2) 1. Preparation of Coating Solution A transparent, homogeneous coating liquid (coating liquid composition) was obtained in the same manner as in Example 1, except that in "1. Preparation of coating liquid" (2) of Example 1, 45.3 g of tetraethyl orthosilicate was used instead of 36.0 g of tetraethyl orthosilicate, and in "1. Preparation of coating liquid" (3) of Example 1, 8.2 g of titanium (IV) tetra-n-butoxide (Ti(OC4H9)4) was used instead of 19.6 g of titanium (IV) tetra-n-butoxide (Ti(OC4H9)4). The resulting coating solution corresponds to a mixture of 90.0 mol % of tetraethyl orthosilicate and 10.0 mol % of titanium(IV) tetra-n-butoxide, where the total amount of tetraethyl orthosilicate and titanium(IV) tetra-n-butoxide added is 100 mol %. In addition, the solids concentration of the obtained coating solution, i.e., the total content of tetraethyl orthosilicate and titanium(IV) tetra-n-butoxide in the coating solution when converted to SiO2 and TiO2, respectively, was 5 wt%.

[0146] 2. Formation of coating film Using the obtained coating liquid, a glass substrate (comparative optical filter 2) was produced in the same manner as in Example 1, having a protective film of a single layer structure on each of the two main surfaces of a glass substrate made of phosphate-based glass (CM500 manufactured by HOYA Corporation, thickness 0.59 mm). In the protective film, the proportion of Ti atoms in the total number of Ti atoms and Si atoms is 10.0 atomic %, and the proportion of Si atoms in the total number of Ti atoms and Si atoms is 90.0 atomic %. Furthermore, in the above protective film, when Ti atoms and Si atoms are converted to TiO2 and SiO2, respectively, the proportion of TiO2 in the total amount of TiO2 and SiO2 is 10.0 mol%, and the proportion of SiO2 in the total amount of TiO2 and SiO2 is 90.0 mol%.

[0147] (Comparative Example 3) 1. Preparation of Coating Solution A transparent, homogeneous coating liquid (coating liquid composition) was obtained in the same manner as in Example 1, except that in "1. Preparation of coating liquid" (2) of Example 1, 40.2 g of tetraethyl orthosilicate was used instead of 36.0 g of tetraethyl orthosilicate, and in "1. Preparation of coating liquid" (3) of Example 1, 14.5 g of titanium (IV) tetra-n-butoxide (Ti(OC4H9)4) was used instead of 19.6 g of titanium (IV) tetra-n-butoxide (Ti(OC4H9)4). The resulting coating solution corresponds to a mixture of 82.0 mol % of tetraethyl orthosilicate and 18.0 mol % of titanium(IV) tetra-n-butoxide, where the total amount of tetraethyl orthosilicate and titanium(IV) tetra-n-butoxide added is 100 mol %. In addition, the solids concentration of the obtained coating solution, i.e., the total content of tetraethyl orthosilicate and titanium(IV) tetra-n-butoxide in the coating solution when converted to SiO2 and TiO2, respectively, was 5 wt%.

[0148] 2. Formation of coating film Using the obtained coating liquid, a glass substrate (comparative optical filter 3) was produced in the same manner as in Example 1, having a protective film of a single layer structure on each of the two main surfaces of a glass substrate made of phosphate-based glass (CM500 manufactured by HOYA Corporation, thickness 0.59 mm). In the protective film, the proportion of Ti atoms in the total number of Ti atoms and Si atoms is 18.0 atomic %, and the proportion of Si atoms in the total number of Ti atoms and Si atoms is 82.0 atomic %. Furthermore, in the above protective film, when the Ti atoms and Si atoms are converted to TiO2 and SiO2, respectively, the proportion of TiO2 in the total amount of TiO2 and SiO2 is 18.0 mol%, and the proportion of SiO2 in the total amount of TiO2 and SiO2 is 82.0 mol%.

[0149] <Weather resistance evaluation> The weather resistance of the optical filters obtained in the above Examples and Comparative Examples was evaluated based on the degree of cloudiness indicated by the haze value shown below. (Evaluation method) (1) Weather resistance life 1 Test pieces cut out from each optical filter were exposed to an environment at a temperature of 65°C and a relative humidity of 90% in a thermo-humidistat chamber. The appearance of the surface on which the weather-resistant protective film was installed was visually observed, and the haze value was measured using a haze meter 10 hours, 20 hours, 30 hours, 40 hours, 50 hours, 75 hours, 100 hours, 150 hours, 200 hours, 250 hours, 300 hours, 350 hours, 400 hours, 500 hours, 750 hours, and 1000 hours after the start of exposure. Based on the judgment that the haze value at which an optical filter becomes cloudy and begins to interfere with use is a haze value of 0.2, the exposure time measured immediately before the exposure time at which the haze value first reached 0.2 or more was defined as the limit time at which the haze value remained at 0.2 or less, and this was defined as the weather resistance life (limit time at which weather resistance was demonstrated). The exposure time associated with this weather resistance life was calculated (for example, if the haze value exceeded 0.2 for the first time 500 hours after the start of the exposure, the weather resistance life of the optical filter would be 400 hours). If the haze value after 1000 hours from the start of the exposure was less than 0.2, the exposure time for the weather resistance life was set to 1000 hours. (2) Weather resistance life 2 The weather resistance life was determined by evaluating test pieces cut out from each optical filter in the same manner as in (1) Weather Resistance Life 1, except that they were exposed to an environment of 85°C temperature and 85% relative humidity in a thermo-humidistat chamber. The results of each example and comparative example are shown in Table 1.

[0150] [Table 1]

[0151] Example 11 1. Preparation of Coating Solution A transparent, homogeneous coating liquid (coating liquid composition) was obtained in the same manner as in Example 1, except that in "1. Preparation of coating liquid" (2) of Example 1, 30.1 g of tetraethyl orthosilicate was used instead of 24.4 g of tetraethyl orthosilicate, and in "1. Preparation of coating liquid" (3) of Example 1, 30.5 g of aluminum (III) tri-sec-butoxide was used instead of 38.5 g of aluminum (III) tri-sec-butoxide. The resulting coating solution was equivalent to a mixture of 53.8 mol % of tetraethyl orthosilicate and 46.2 mol % of aluminum (III) tri-sec-butoxide, where the total amount of tetraethyl orthosilicate and aluminum (III) tri-sec-butoxide added was taken as 100 mol %. The solids concentration of the obtained coating solution, i.e., the total content of tetraethyl orthosilicate and aluminum(III) tri-sec-butoxide in the coating solution when converted to SiO2 and Al2O3, respectively, was 5 wt%.

[0152] 2. Formation of coating film Using the obtained coating liquid, a glass substrate (optical filter 11) having a protective film of a single layer structure on each of the two main surfaces of a glass substrate made of phosphate-based glass (CM500 manufactured by HOYA Corporation, thickness 0.59 mm) was produced in the same manner as in Example 1. In the protective film, the proportion of Al atoms in the total number of Al atoms and Si atoms is 46.2 atomic %, and the proportion of Si atoms in the total number of Al atoms and Si atoms is 53.8 atomic %. In addition, in the above protective film, when the Al atoms and Si atoms are converted to Al2O3 and SiO2, respectively, the proportion of Al2O3 in the total amount of Al2O3 and SiO2 is 30.0 mol%, and the proportion of SiO2 in the total amount of Al2O3 and SiO2 is 70.0 mol%.

[0153] <Confirmation of chemical bond (Al-O-Si bond)> (1) 13.5 g of the coating solution prepared in 1 above was poured into a polymethylpentene petri dish with an inner diameter of 85 mm and a depth of 15 mm, and the dish was covered and left in a thermostatic chamber at an internal temperature of 60°C to gel and dry, thereby obtaining a plate-shaped sample with a thickness of 0.5 mm. (2) The plate-shaped sample obtained in (1) was heat-treated in a muffle furnace at 280°C for 10 minutes to obtain a measurement sample. (3) Using a microscopic FT-IR (Digital Lab Excalibur+UMA600), the measurement sample obtained in (2) was subjected to FT-IR measurement under the following measurement conditions. (Measurement conditions) Measurement mode: Transmission mode Measurement area: 500~1000cm -1 Number of times accumulated: 128 Resolution: 4cm -1 Scan speed: 5kHz (4) As a result of the FT-IR measurement according to (3) above, 555 cm -1 , 852cm -1 , 911cm -1 An absorption peak was observed. According to J Sol-Gel Sci Technol (2010) 56:47-52, NP Damayanti, "Preparation of Superhydrophobic PET fabric from Al2O3-SiO2 hybrid: geometrical approach to create high contact angle surface from low contact angle material," when FT-IR was measured, an absorption peak due to Si-O-Al bond was observed at 557 cm -1 、 850cm -1 and 902 cm -1 It has been reported that the β-glucan is detected in the β-glucan (Fig. 4 and the right column on page 51 of the above-mentioned reference). In the measurement sample used in this measurement, all of the absorption peaks corresponding to the above absorption peaks were detected by the FT-IR measurement, and it was therefore confirmed that the Si atoms and Al atoms constituting the coating film constituting the optical filter 11 obtained in this example form chemical bonds (Si-O-Al bonds) between the Si atoms and Al atoms via oxygen bonds.

[0154] Example 12 1. Preparation of Coating Solution A transparent, homogeneous coating liquid (coating liquid composition) was obtained in the same manner as in Example 1, except that in "1. Preparation of coating liquid" (2) of Example 1, 33.2 g of tetraethyl orthosilicate was used instead of 24.4 g of tetraethyl orthosilicate, and in "1. Preparation of coating liquid" (3) of Example 1, 26.2 g of aluminum (III) tri-sec-butoxide was used instead of 38.5 g of aluminum (III) tri-sec-butoxide. The resulting coating solution was equivalent to a mixture of 60.0 mol % of tetraethyl orthosilicate and 40.0 mol % of aluminum (III) tri-sec-butoxide, where the total amount of tetraethyl orthosilicate and aluminum (III) tri-sec-butoxide added was taken as 100 mol %. The solids concentration of the obtained coating solution, i.e., the total content of tetraethyl orthosilicate and aluminum(III) tri-sec-butoxide in the coating solution when converted to SiO2 and Al2O3, respectively, was 5 wt%. 2. Formation of coating film Using the obtained coating liquid, a glass substrate (optical filter 12) having a protective film of a single layer structure on each of the two main surfaces of a glass substrate made of phosphate-based glass (CM500 manufactured by HOYA Corporation, thickness 0.59 mm) was produced in the same manner as in Example 1. In the protective film, the proportion of Al atoms in the total number of Al atoms and Si atoms is 40.0 atomic %, and the proportion of Si atoms in the total number of Al atoms and Si atoms is 60.0 atomic %. In addition, in the above protective film, when the Al atoms and Si atoms are converted to Al2O3 and SiO2, respectively, the proportion of Al2O3 in the total amount of Al2O3 and SiO2 is 25.0 mol%, and the proportion of SiO2 in the total amount of Al2O3 and SiO2 is 75.0 mol%.

[0155] Example 13 1. Preparation of Coating Solution A transparent, homogeneous coating liquid (coating liquid composition) was obtained in the same manner as in Example 1, except that in "1. Preparation of coating liquid" (2) of Example 1, 19.3 g of tetraethyl orthosilicate was used instead of 24.4 g of tetraethyl orthosilicate, and in "1. Preparation of coating liquid" (3) of Example 1, 45.6 g of aluminum (III) tri-sec-butoxide was used instead of 38.5 g of aluminum (III) tri-sec-butoxide. The resulting coating solution was equivalent to a mixture of 33.3 mol % of tetraethyl orthosilicate and 66.7 mol % of aluminum (III) tri-sec-butoxide, where the total amount of tetraethyl orthosilicate and aluminum (III) tri-sec-butoxide added was taken as 100 mol %. The solids concentration of the obtained coating solution, i.e., the total content of tetraethyl orthosilicate and aluminum(III) tri-sec-butoxide in the coating solution when converted to SiO2 and Al2O3, respectively, was 5 wt%. 2. Formation of coating film Using the obtained coating liquid, a glass substrate (optical filter 13) having a protective film of a single layer structure on each of the two main surfaces of a glass substrate made of phosphate-based glass (CM500 manufactured by HOYA Corporation, thickness 0.59 mm) was produced in the same manner as in Example 1. In the protective film, the proportion of Al atoms in the total number of Al atoms and Si atoms is 66.7 atomic %, and the proportion of Si atoms in the total number of Al atoms and Si atoms is 33.3 atomic %. In addition, in the above protective film, when the Al atoms and Si atoms are converted to Al2O3 and SiO2, respectively, the proportion of Al2O3 in the total amount of Al2O3 and SiO2 is 50.0 mol%, and the proportion of SiO2 in the total amount of Al2O3 and SiO2 is 50.0 mol%.

[0156] Comparative Example 4 1. Preparation of Coating Solution A transparent, homogeneous coating liquid (coating liquid composition) was obtained in the same manner as in Example 1, except that in "1. Preparation of coating liquid" (2) of Example 1, 52.0 g of tetraethyl orthosilicate was used instead of 24.4 g of tetraethyl orthosilicate, and in "1. Preparation of coating liquid" (3) of Example 1, aluminum (III) tri-sec-butoxide was not used. The obtained coating solution corresponds to 100.0 mol % of tetraethyl orthosilicate. The solid concentration of the obtained coating liquid, that is, the content of tetraethyl orthosilicate in the coating liquid when the tetraethyl orthosilicate in the coating liquid was converted to SiO2, was 5 wt%. 2. Formation of coating film Using the obtained coating liquid, a glass substrate (comparative optical filter 4) was produced in the same manner as in Example 1, having a protective film of a single layer structure on each of the two main surfaces of a glass substrate made of phosphate-based glass (CM500 manufactured by HOYA Corporation, thickness 0.59 mm). In the protective film, the proportion of Si atoms to the total number of Si atoms is 100.0 atomic %. In addition, in the protective film, when Si atoms are converted into SiO2, the proportion of SiO2 is 100.0 mol%.

[0157] <Confirmation of chemical bond (Al-O-Si bond)> In the same manner as in Example 10, a measurement sample was prepared using the coating liquid prepared in 1 above, and the obtained measurement sample was subjected to FT-IR measurement. As mentioned above, when FT-IR was measured, the absorption peak due to the Si-O-Al bond was observed at 557 cm -1 , 850cm -1 and 902 cm -1 However, in the measurement sample used in this measurement, no absorption peak could be detected in the above wavelength region. Therefore, it was confirmed that in the coating film constituting the comparative optical filter 4 obtained in this comparative example, no chemical bond (Si-O-Al bond) was formed between Si atoms and Al atoms via an oxygen bond.

[0158] <Weather resistance evaluation> The optical filters obtained in the above Examples and Comparative Examples were evaluated according to the above-mentioned "weather resistance life 1" and "weather resistance life 2" as weather resistance evaluation methods using haze values ​​(cloudiness). The results of each example and comparative example are shown in Table 2.

[0159] [Table 2]

[0160] Tables 1 and 2 show that the optical filters obtained in Examples 1 to 13 have a weather-resistant protective film having a single-layer structure on the surface of an absorbing glass substrate made of phosphate glass, the weather-resistant protective film containing Si atoms and one or more atoms selected from Ti, Zr, and Al, and the proportion of the total number of Ti, Zr, and Al atoms to the total number of Si, Ti, Zr, and Al atoms is greater than 20.0 atomic % and less than 75.0 atomic %. As a result, the weather-resistant life (weather-resistant life 1 and weather-resistant life 2), defined by the limit time at which the haze value is 0.2 or less, is sufficiently long, ranging from 200 hours (200 hours) to 1000 hours (1000 hours). Furthermore, visual observation showed that the surface maintained a homogeneous and transparent state until the end of the weather-resistant life, demonstrating excellent weather resistance. Furthermore, from the results of Example 11 and the like, it was considered that the optical filters obtained in the above Examples have a specific structure in which Si atoms and one or more atoms selected from Ti atoms, Zr atoms, and Al atoms that constitute the weather-resistant protective film are bonded in a three-dimensional network pattern by chemical bonds between atoms of the same kind or between atoms of different kinds via oxygen atoms, and therefore can exhibit excellent weather resistance.

[0161] On the other hand, as can be seen from Table 1, the optical filter obtained in Comparative Example 1 did not have a protective film on the surface of the absorbing glass substrate made of phosphate-based glass, and therefore the haze value exceeded 0.2 after 10 hours or 5 hours of exposure in a constant temperature and humidity chamber.In addition, visual observation revealed that the surface had deliquesced, become sticky, and deteriorated, indicating that the filter had poor weather resistance. Furthermore, Table 1 shows that the optical filter obtained in Comparative Example 2 has a weather-resistant protective film formed on the surface of an absorbing glass substrate made of phosphate-based glass, and the ratio of the number of Ti atoms to the total number of Si atoms and Ti atoms is outside the specified range. Therefore, the weather-resistant life, defined as the limit time for which a haze value of 0.2 or less can be maintained, is short at 50 hours (50 hours) or 10 hours (10 hours), and the weather-resistant life is poor. In addition, Table 1 shows that the optical filter obtained in Comparative Example 3 has a weather-resistant protective film formed on the surface of an absorbing glass substrate made of phosphate-based glass, and the ratio of the number of Ti atoms to the total number of Si atoms and Ti atoms is outside the specified range. Therefore, the weather-resistant life, which is defined as the limit time for which a haze value of 0.2 or less can be maintained, is short at 150 hours (150 hours) or 40 hours (40 hours), and the weather-resistant life is poor. From the results of Comparative Example 4, it was concluded that the optical filters obtained in the above Comparative Examples had poor weather resistance because they did not use a weather-resistant protective film having a specific structure in which Si atoms and one or more atoms selected from Ti atoms, Zr atoms, and Al atoms are bonded in a three-dimensional mesh pattern by chemical bonds via oxygen atoms between atoms of the same type or between atoms of different types. [Explanation of symbols]

[0162] 1 Optical element, optical filter or infrared cut filter (IRCF) L lens CG cover glass IC image sensor G Glass substrate P Weatherproof protective film AR anti-reflection coating R Resin film

Claims

1. On at least one main surface of a glass substrate made of phosphate glass or fluorophosphate glass, containing, together with Si atoms, one or more atoms selected from Zr atoms and Al atoms, the ratio of the total number of Zr atoms and Al atoms to the total number of Si atoms, Zr atoms and Al atoms is 25.0 atomic % or more and 75.0 atomic % or less; A weather-resistant protective film having a single layer structure is provided. An optical element characterized by:

2. 2. The optical element according to claim 1, wherein Si atoms and one or more atoms selected from Zr atoms and Al atoms constituting the weather-resistant protective film are bonded in a three-dimensional network pattern by chemical bonds between atoms of the same kind or between atoms of different kinds via oxygen atoms.

3. 2. The optical element according to claim 1, wherein the weather-resistant protective film contains 8.3 to 27.5 atomic % of Si atoms, 6.6 to 28.5 atomic % of one or more atoms selected from Zr atoms and Al atoms, and 61.9 to 66.6 atomic % of oxygen atoms.

4. The weather-resistant protective film is (I) one or more silicon compounds selected from alkoxysilanes, alkoxysilane derivatives, and oligomers of polymers of one or more of these; (IIb) an oligomer consisting of alkoxyzirconium, an alkoxyzirconium derivative, or a polymer of one or more of these; and (IIc) Alkoxyaluminum, alkoxyaluminum derivatives, or oligomers comprising polymers of one or more of these. and one or more polyvalent metal compounds selected from The optical element according to claim 1 .

5. A glass substrate made of phosphate glass or fluorophosphate glass is provided on at least one main surface thereof with a compound represented by the following general formula (i): Si(OR １ )(OR ２ ) (OR ３ ) (OR ４ ) (i) (However, R １ , R ２ , R ３ and R ４ are linear or branched hydrocarbon groups having 1 to 10 carbon atoms, and may be the same or different. and an alkoxysilane represented by The following general formula (iib) Zr(OR ９ )(OR １０ )(OR １１ )(OR １２ ) (iib) (However, R ９ , R １０ , R １１ and R １２ are linear or branched hydrocarbon groups having 1 to 10 carbon atoms, and may be the same or different from each other.) and the following general formula (iic): Al(OR １３ )(OR １４ )(OR １５ ) (iic) (However, R １３ , R １４ and R １５ are linear or branched hydrocarbon groups having 1 to 10 carbon atoms, and may be the same or different. and a weather-resistant protective film containing a hydrolysis / dehydration condensation product with one or more metal alkoxides selected from the group consisting of The optical element according to claim 1 .

6. When the total content of the alkoxysilane represented by the general formula (i) and one or more metal alkoxides selected from the general formulae (iib) to (iic) is taken as 100.0 mol %, the weather-resistant protective film has a The optical element according to claim 5, comprising a hydrolysis / dehydration condensation product of 25.0 mol % or more and 75.0 mol % or less of an alkoxysilane represented by the general formula (i) and 25.0 mol % or more and 75.0 mol % or less of one or more metal alkoxides selected from the general formulas (iib) to (iic).

7. 2. The optical element according to claim 1, wherein the glass substrate is an absorbing glass substrate that absorbs ultraviolet light or near-infrared light.

8. 2. The optical element according to claim 1, further comprising a resin film or an anti-reflection film provided on the weather-resistant protective film.

9. 2. The optical element according to claim 1, wherein a resin film and an anti-reflection film are further provided in this order on the weather-resistant protective film, or an anti-reflection film and a resin film are further provided in this order.

10. 10. The optical element according to claim 1, wherein the optical element is an optical filter.

11. An imaging device comprising an optical element according to any one of claims 1 to 9 as an optical filter, together with a solid-state imaging element and an imaging lens.

Images