Method for manufacturing high-refractive-index film, method for manufacturing optical member having high-refractive-index film, high-refractive-index film, and optical member having high-refractive-index film

Abstract

The purpose of the present invention is to provide: a method for manufacturing a high-refractive-index film capable of improving a refractive index through a wet treatment; and a method for manufacturing an optical member having a high-refractive-index film. The present invention pertains to a method for manufacturing a high-refractive-index film, the method comprising: a fine particle dispersion film formation step for forming a fine particle dispersion film containing metal oxide fine particles; and a wet treatment step for applying a titanoxane-containing liquid onto the fine particle dispersion film formed by the fine particle dispersion film formation step.

Description

Method for manufacturing a high refractive index film, method for manufacturing an optical member having a high refractive index film, high refractive index film and optical member having a high refractive index film

[0001] The present disclosure relates to a method for manufacturing a high-refractive index film, a method for manufacturing an optical member having a high-refractive index film, ... and an optical member having a high-refractive index film.

[0002] High refractive index films are used in various optical components. A known method for producing a high refractive index film is to form a fine particle dispersion film containing metal oxide fine particles on the surface of a substrate. It is also known to perform post-treatment on the fine particle dispersion film formed on the surface of the substrate in order to further increase the refractive index.

[0003] For example, Non-Patent Document 1 discloses a method for improving the refractive index by casting a titania microparticle dispersion onto a substrate surface to form a layer of microparticles, and filling the gaps between the microparticles by titania atomic layer deposition (ALD).

[0004] ACS Appl. Nano Mater. 2003, 6, 3, 2009-2019

[0005] In the method described in Non-Patent Document 1, the refractive index is improved by filling the voids between metal oxide particles using a dry process, the ALD method, after a wet process. However, the ALD method requires a vacuum state during the process, which increases production costs, consumes a large amount of energy, and may also cause a burden on the environment. On the other hand, since a vacuum state is not required during the process, the wet process has a relatively low production cost, and may also reduce energy consumption and the burden on the environment. However, no method for improving the refractive index by a wet process is known. Furthermore, the inventors' investigations have revealed that the high refractive index film obtained by the method described in Non-Patent Document 1 has a rough surface due to the production method, which involves wet processing followed by dry processing.

[0006] The present disclosure aims to solve the above-mentioned problems newly discovered by the present inventors, and to provide a method for producing a high-refractive index film that can improve the refractive index by wet processing, and a method for producing an optical component having a high-refractive index film. Another object of the present disclosure is to solve the above-mentioned problems newly discovered by the present inventors, and to provide a high-refractive index film having a smooth surface and an optical component having the high-refractive index film.

[0007] As a result of extensive research, the present inventors have found that wet treatment using an acrylic resin does not sufficiently improve the refractive index, but that wet treatment using titanoxane significantly improves the refractive index, and have thus completed the present disclosure. That is, the present disclosure (1) relates to a method for producing a high refractive index film, which includes: a fine particle dispersion film forming step of forming a fine particle dispersion film containing metal oxide fine particles; and a wet treatment step of applying a liquid containing titanoxane onto the fine particle dispersion film formed by the fine particle dispersion film forming step.

[0008] The present disclosure (2) relates to a method for producing a high refractive index film according to the present disclosure (1), wherein the fine particle dispersion film contains metal oxide fine particles and a resin.

[0009] The present disclosure (3) relates to the method for producing a high refractive index film according to the present disclosure (1) or (2), wherein the metal oxide is at least one selected from the group consisting of titanium oxide, zirconium oxide, niobium oxide, cerium oxide, zinc oxide, indium oxide, tin oxide, indium tin oxide, and antimony oxide.

[0010] The present disclosure (4) relates to the method for producing a high refractive index film according to the present disclosure (1) or (2), wherein the metal oxide is at least one selected from the group consisting of titanium oxide, zirconium oxide, niobium oxide, cerium oxide, and zinc oxide.

[0011] The present disclosure (5) relates to the method for producing a high refractive index film according to the present disclosure (1) or (2), wherein the metal oxide is at least one selected from the group consisting of titanium oxide, zirconium oxide, and niobium oxide.

[0012] The present disclosure (6) relates to a method for producing a high refractive index film according to any one of the present disclosures (1) to (5), including a titanoxane-containing film-forming step of forming a titanoxane-containing film on the fine particle-dispersed film by heating after the wet treatment step.

[0013] The present disclosure (7) relates to the method for producing a high refractive index film according to any one of the present disclosures (1) to (5), wherein the content of titanoxane in 100% by mass of the liquid containing titanoxane is 1 to 20% by mass.

[0014] The present disclosure (8) relates to a method for producing an optical component having a high refractive index film, the method including a step of producing a high refractive index film by the method for producing a high refractive index film according to any one of the present disclosures (1) to (7).

[0015] The present disclosure (9) relates to the method for producing an optical member according to the present disclosure (8), wherein the optical member is a light-emitting element.

[0016] The present inventors have found that the surface of a titanoxane-containing film obtained by wet treatment with titanoxane is smooth, and have completed the present disclosure. That is, the present disclosure (10) relates to a high refractive index film having a microparticle-dispersed film containing metal oxide microparticles and a titanoxane-containing film on the microparticle-dispersed film, wherein the arithmetic mean roughness (Ra) of the titanoxane-containing film is 5 nm or less.

[0017] The present disclosure (11) relates to the high refractive index film according to the present disclosure (10), wherein the metal oxide is at least one selected from the group consisting of titanium oxide, zirconium oxide, niobium oxide, cerium oxide, zinc oxide, indium oxide, tin oxide, indium tin oxide, and antimony oxide.

[0018] The present disclosure (12) relates to the high refractive index film according to the present disclosure (10), wherein the metal oxide is at least one selected from the group consisting of titanium oxide, zirconium oxide, niobium oxide, cerium oxide, and zinc oxide.

[0019] The present disclosure (13) relates to the high refractive index film according to the present disclosure (10), wherein the metal oxide is at least one selected from the group consisting of titanium oxide, zirconium oxide, and niobium oxide.

[0020] The present disclosure (14) relates to an optical member having the high refractive index film according to any one of the present disclosures (10) to (13).

[0021] The present disclosure (15) relates to the optical member according to the present disclosure (14), wherein the optical member is a light-emitting element.

[0022] The method for manufacturing a high refractive index film of the present disclosure includes a microparticle dispersion film formation step of forming a microparticle dispersion film containing metal oxide microparticles, and a wet treatment step of applying a liquid containing titanoxane onto the microparticle dispersion film formed by the microparticle dispersion film formation step. Therefore, it is possible to provide a method for manufacturing a high refractive index film that can improve the refractive index by wet treatment, and a method for manufacturing an optical element having a high refractive index film.

[0023] The high-refractive index film of the present disclosure comprises a microparticle-dispersed film containing metal oxide microparticles and a titanoxane-containing film on the microparticle-dispersed film, and since the arithmetic mean roughness (Ra) of the titanoxane-containing film is 5 nm or less, it is possible to provide a high-refractive index film with a smooth surface and an optical element having the high-refractive index film.

[0024] Fig. 1 is a cross-sectional view schematically showing an example of a high refractive index film according to the present disclosure, and Fig. 2 is a cross-sectional view schematically showing an example of an optical member according to the present disclosure.

[0025] The present disclosure will be described in detail below, but the following description of the constituent elements is an example of an embodiment of the present disclosure, and the present disclosure is not limited to these specific details. Various modifications can be made within the scope of the gist of the present disclosure.

[0026] In this specification, unless otherwise specified, the expression "X to Y" in the description of a numerical range means at least X and at most Y. For example, "1 to 5% by mass" means "at least 1% by mass and at most 5% by mass."

[0027] The method for producing a high refractive index film according to the present disclosure includes a microparticle-dispersed film forming step of forming a microparticle-dispersed film containing metal oxide microparticles, and a wet treatment step of applying a liquid containing titanoxane onto the microparticle-dispersed film formed in the microparticle-dispersed film forming step. This makes it possible to provide a method for producing a high refractive index film capable of improving the refractive index by wet treatment, and a method for producing an optical member having a high refractive index film.

[0028] The reason why the above-mentioned effects are obtained is not entirely clear, but it is presumed that the following mechanism is involved.

[0029] A titanoxane-containing film can be formed on the fine particle dispersion film by applying a wet treatment process, such as coating the fine particle dispersion film with a liquid containing titanoxane. The presence of this titanoxane-containing film improves the refractive index. It is believed that the improvement in the refractive index due to the presence of the titanoxane-containing film is achieved because the voids in the fine particle dispersion film are reduced by the titanoxane-containing film, which itself has a high refractive index.

[0030] The high refractive index film of the present disclosure comprises a microparticle-dispersed film containing metal oxide microparticles and a titanoxane-containing film disposed on the microparticle-dispersed film, wherein the titanoxane-containing film has an arithmetic mean roughness (Ra) of 5 nm or less. This provides a high refractive index and a smooth surface. A high refractive index film with such properties can be suitably used for optical components. The smooth surface is particularly advantageous in that it easily suppresses scattering and provides high transparency.

[0031] The reason why the above-mentioned effects are obtained is not entirely clear, but it is presumed that the following mechanism is involved.

[0032] As described above, a titanoxane-containing film can be formed on the fine particle dispersion film by carrying out a wet treatment process or the like in which a liquid containing titanoxane is applied onto the fine particle dispersion film, and the presence of this titanoxane-containing film improves the refractive index. Furthermore, this titanoxane-containing film has a smooth surface. It is presumed that the smooth surface of the titanoxane-containing film is due to the film surface being flattened when the titanoxane-containing film is formed. This effect of flattening the surface is more preferably exhibited when the titanoxane-containing film is formed by wet treatment. This is because the surface of the coating liquid is easily flattened when wet treatment is carried out, and as a result, the surface of the titanoxane-containing film is more preferably flattened. Therefore, it is preferable that the titanoxane-containing film is formed by wet treatment.

[0033] <Method for manufacturing high refractive index film> The method for manufacturing a high refractive index film of the present disclosure includes a microparticle dispersion film formation step of forming a microparticle dispersion film containing metal oxide microparticles, and a wet treatment step of applying a liquid containing titanoxane onto the microparticle dispersion film formed in the microparticle dispersion film formation step.

[0034] <<Fine Particle Dispersed Film Forming Step>> In the fine particle dispersed film forming step, a fine particle dispersed film containing metal oxide fine particles is formed.

[0035] Before describing the fine particle dispersed film forming process, the fine particle dispersed film will be described first.

[0036] The fine particle dispersion film contains metal oxide fine particles. The metal oxide constituting the metal oxide fine particles is not particularly limited as long as it is an oxide of a metal, and examples thereof include titanium oxide, zirconium oxide, niobium oxide, cerium oxide, zinc oxide, indium oxide, tin oxide, indium tin oxide, and antimony oxide. These may be used alone or in combination of two or more. Among these, titanium oxide, zirconium oxide, niobium oxide, cerium oxide, and zinc oxide are preferred because they can provide a higher refractive index, and titanium oxide, zirconium oxide, and niobium oxide are more preferred.

[0037] The D50 of the metal oxide fine particles is preferably 3 to 50 nm, more preferably 4 to 40 nm, and even more preferably 5 to 30 nm. Within this range, a higher refractive index tends to be obtained. In this specification, the D50 of the metal oxide fine particles refers to the median diameter (center value) when each particle is considered to be a sphere (based on the scattering intensity in dynamic light scattering), and refers to a statistical value in which half of the particles are above this value and the remaining half are below this value, and is measured by the method described in the Examples. In this specification, the metal oxide fine particles refer to metal oxide particles having a D50 within the above-mentioned preferred numerical range.

[0038] The content of the metal oxide fine particles in the fine particle dispersion film (100% by mass) may be 100% by mass, but is preferably 50 to 95% by mass, more preferably 70 to 95% by mass, and even more preferably 80 to 90% by mass. Within the above range, a higher refractive index tends to be obtained.

[0039] The fine particle dispersion film preferably contains a resin in addition to the metal oxide fine particles. Thereby, for example, when a fine particle dispersion film coating solution described later is applied to a substrate surface to form a fine particle dispersion film, the metal oxide fine particles are less likely to aggregate with each other because the coating solution contains a resin or a resin precursor component, and as a result, a homogeneous fine particle dispersion film tends to be formed.

[0040] Furthermore, by including a resin in the microparticle dispersion film in addition to metal oxide microparticles, the wet treatment step can be carried out more suitably. In the method described in Non-Patent Document 1, the microparticle dispersion film does not contain a resin, so when wet treatment is carried out on such a microparticle dispersion film, there is a risk that the metal particles on the substrate will flow. However, by including a resin in the microparticle dispersion film in addition to metal oxide microparticles, this concern is resolved, and the wet treatment step can be carried out more suitably.

[0041] The resin is not particularly limited as long as it functions as a binder resin, and examples thereof include titanoxane, siloxane, acrylic resin, epoxy resin, polyimide, polybenzoxazole, etc. These may be used alone or in combination of two or more. Among these, titanoxane, siloxane, and acrylic resin are preferred.

[0042] In this specification, titanoxane refers to a polymer containing a repeating structure of titanium-oxygen-titanium bonds, more specifically, a polymer containing a condensate (hydrolysis condensate) of titanium alkoxide. Note that the condensate (hydrolysis condensate) of titanium alkoxide refers to a condensate (hydrolysis condensate) formed by a condensation reaction (hydrolysis condensation reaction) of titanium alkoxide, and other similar descriptions are the same.

[0043] Titanoxane may contain other structural units in addition to the condensate (hydrolysis condensate) of titanium alkoxide. The other structural units are not particularly limited, and examples thereof include the condensate (hydrolysis condensate) of silane alkoxide described below. These may be used alone or in combination of two or more.

[0044] In this specification, as long as a condensate (hydrolysis condensate) of titanium alkoxide is contained, it is treated as titanoxane even if the content is small. For example, a composite of titanoxane and siloxane is also treated as titanoxane. This composite may contain a repeating structure of titanium-oxygen-titanium bonds and a repeating structure of silicon-oxygen-silicon bonds, in addition to the repeating structure of titanium-oxygen-silicon bonds.

[0045] The content of the titanium alkoxide condensate in 100% by mass of titanoxane is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and may be 100% by mass.

[0046] In this specification, siloxane refers to a polymer containing a repeating structure of silicon-oxygen-silicon bonds, more specifically, a polymer containing a silane alkoxide condensate (hydrolysis condensate). The content of the silane alkoxide condensate in 100% by mass of siloxane is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and may even be 100% by mass.

[0047] Here, a brief description will be given of a method for producing titanoxane. Titanoxane (a condensate (hydrolysis condensate) of titanium alkoxide) can be obtained, for example, by subjecting titanium alkoxide to a polycondensation reaction (hydrolysis condensation) using a known method, such as those described in JP-A Nos. 2000-86769, 2008-156280, and 2018-49075. Furthermore, as long as at least one titanium alkoxide is contained, partial hydrolysis condensation may be carried out in combination with an alkoxysilane that is not a titanium alkoxide.

[0048] As the titanium alkoxide, those represented by the following general formula (1) can be used. These may be used alone or in combination of two or more kinds. Ti(OR １ ) ４ (1) (In formula (1), R １ represents an alkyl group having 1 to 12 carbon atoms. １ The number of carbon atoms in the alkyl group is 1 to 12, preferably 1 to 6, and more preferably 1 to 4. Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a normal butyl group, a tertiary butyl group, a pentyl group, a hexyl group, and a 2-ethylhexyl group. １ The four groups represented by may be different from each other or the same.

[0049] Specific examples of titanium alkoxides include titanium tetramethoxide, titanium tetraisopropoxide, titanium tetranormal propoxide, titanium tetraisobutoxide, titanium tetranormal butoxide, titanium tetraethoxide, titanium tetra-2-ethylhexoside, tetratertiarybutyl titanate, etc. These may be used alone or in combination of two or more.

[0050] The resin content in 100% by mass of the fine particle dispersion film is preferably 5 to 50% by mass, more preferably 5 to 30% by mass, and even more preferably 5 to 20% by mass. Within the above range, there is a tendency that the wet treatment step can be carried out more suitably.

[0051] The fine particle dispersion film may contain, in addition to the metal oxide fine particles and the resin, for example, an adhesion imparting agent, a surfactant, etc. These may be used alone or in combination of two or more kinds.

[0052] The total content of the metal oxide fine particles and the resin in 100% by mass of the fine particle dispersion film is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and may even be 100% by mass. Within the above range, a higher refractive index tends to be obtained.

[0053] The thickness of the fine particle dispersion film is not particularly limited, and is, for example, 100 nm to 10 μm.

[0054] Next, the step of forming a fine particle dispersed film will be described. The step of forming a fine particle dispersed film may be carried out in the same manner as a known method.

[0055] As an example of the fine particle dispersion film forming process, a case where the fine particle dispersion film contains metal oxide fine particles and a resin will be briefly described. For example, when the resin is titanoxane or siloxane, the metal oxide fine particles, the resin, and a solvent are mixed to prepare a fine particle dispersion film coating liquid. On the other hand, when the resin is an acrylic resin, the metal oxide fine particles, the resin, and a solvent may be mixed to prepare a fine particle dispersion film coating liquid. Alternatively, instead of the resin, a monomer for forming the resin, an auxiliary agent necessary for forming the resin, such as a polymerization initiator, may be mixed to prepare the fine particle dispersion film coating liquid.

[0056] The solvent is not particularly limited, and examples thereof include ketones, alcohols, polyhydric alcohols, esters, aromatic solvents, ethers, fluorine-based solvents, etc. These may be used alone or in combination of two or more. Among these, alcohols, polyhydric alcohols, and esters are preferred, and alcohols and polyhydric alcohols are more preferred.

[0057] Examples of ketones include acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl isobutyl ketone, methyl isopentyl ketone, 2-heptanone, etc. Examples of alcohols include isopropanol, butanol, isobutanol, n-pentanol, isopentanol, tert-pentanol, 4-methyl-2-pentanol, 3-methyl-3-pentanol, 2,3-dimethyl-2-pentanol, n-hexanol, n-heptanol, 2-heptanol, n-octanol, n-decanol, s-amyl alcohol, t-amyl alcohol, isoamyl alcohol, 2-ethyl-1-butanol, lauryl alcohol, hexyldecanol, oleyl alcohol, etc. Examples of polyhydric alcohols include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, ethylene glycol monoacetate, ethylene glycol dimethyl ether (EDC), diethylene glycol monoacetate, propylene glycol monoacetate, dipropylene glycol monoacetate, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), and derivatives of these polyhydric alcohols. Examples of esters include methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, γ-butyrolactone (GBL), and the like. Examples of aromatic solvents include toluene and xylene. Examples of ethers include diethyl ether, dioxane, anisole, and diisopropyl ether. Examples of fluorine-based solvents include hexafluoroisopropyl alcohol, etc. Among these, propylene glycol monomethyl ether (PGME) and propylene glycol monomethyl ether acetate (PGMEA) are preferred, and propylene glycol monomethyl ether (PGME) is more preferred.

[0058] The monomer for forming the resin is not particularly limited, and a monomer appropriate for the resin to be formed may be used. For example, if an acrylic resin is to be formed, an acrylic acid ester may be used. Those skilled in the art will be able to appropriately select a monomer appropriate for the resin to be formed. The monomer may be used alone or in combination of two or more types.

[0059] The auxiliary agent required for forming the resin is not particularly limited, and an auxiliary agent may be used depending on the resin to be formed and the polymerization method, and a person skilled in the art can appropriately select it. Specific examples of the auxiliary agent include a polymerization initiator, a chain transfer agent, a chelating agent, an oxygen scavenger, etc. These may be used alone or in combination of two or more. Among them, a polymerization initiator is preferred.

[0060] The method for mixing the components is not particularly limited, and a known stirrer may be used to mix the components to prepare a microparticle-dispersed film coating solution. The solids concentration of the microparticle-dispersed film coating solution is also not particularly limited, and may be, for example, 5 to 30 mass % for ease of application. The content of each component in the microparticle-dispersed film coating solution may be appropriately adjusted so that the content of each component in the microparticle-dispersed film to be formed is the desired value. When titanoxane or siloxane is used as the resin, the mixed solution may be stirred at 20 to 100°C for 1 to 5 hours when mixing metal oxide microparticles, a resin, and a solvent to prepare a microparticle-dispersed film coating solution. This tends to suppress aggregation of the microparticles in the microparticle-dispersed film.

[0061] Next, the prepared fine particle dispersion film coating solution is applied to the surface of any substrate such as a silicon wafer. The coating method is not particularly limited, and examples thereof include dipping, spraying, roll coating, spin coating, curtain coating, slit die coating, bar coating, and inkjet coating. Of these, spin coating is preferred.

[0062] After the fine particle dispersion film coating liquid is applied to the surface of the substrate, the fine particle dispersion film is formed by appropriately heating or irradiating with active energy rays (for example, ultraviolet rays).

[0063] For example, when the resin is titanoxane or siloxane, the polymerization reaction of the resin is further promoted by heating, and a fine particle dispersion film is formed. The heating temperature and heating time are the same as those in the titanoxane-containing film-forming step described later, including preferred embodiments.

[0064] Furthermore, for example, when the fine particle dispersion film coating liquid contains an acrylic acid ester and a photopolymerization initiator, an acrylic resin is formed by irradiating ultraviolet light, and a fine particle dispersion film is formed. The conditions after applying the fine particle dispersion film coating liquid to the substrate surface can be appropriately set by a person skilled in the art.

[0065] <<Wet Treatment Step>> In the wet treatment step, a liquid containing titanoxane is applied onto the fine particle dispersion film formed in the fine particle dispersion film forming step.

[0066] The coating method is not particularly limited, and examples thereof include dipping, spraying, roll coating, spin coating, curtain coating, slit die coating, bar coating, ink jet coating, etc. Of these, spin coating is preferred.

[0067] The content of titanoxane in 100% by mass of the titanoxane-containing liquid is preferably 1 to 20% by mass, more preferably 5 to 20% by mass, and even more preferably 5 to 15% by mass, which tends to provide a coating film with a high refractive index and no cracks.

[0068] The titanoxane is as described above. As described above, the content of the titanium alkoxide condensate in 100% by mass of titanoxane is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and may be 100% by mass.

[0069] The liquid containing titanoxane is a liquid, and therefore contains at least titanoxane and a solvent. The solvent, including preferred embodiments thereof, is the same as the solvent described in the description of the fine particle dispersion film forming step.

[0070] The liquid containing titanoxane may contain, in addition to titanoxane and a solvent, for example, an adhesion promoter, a surfactant, etc. These may be used alone or in combination of two or more.

[0071] The total content of titanoxane and solvent in 100% by mass of the titanoxane-containing liquid is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and may even be 100% by mass. Within this range, a higher refractive index tends to be obtained.

[0072] Before applying the titanoxane-containing liquid onto the fine particle dispersion film formed in the fine particle dispersion film forming step, the surface of the fine particle dispersion film may be subjected to ultraviolet light treatment and / or ozone treatment, which tends to make the surface of the fine particle dispersion film clean and more suitable for applying the titanoxane-containing liquid.

[0073] <<Titanoxane-Containing Film Forming Step>> In the titanoxane-containing film forming step, after the wet treatment step, heating is performed to form a titanoxane-containing film on the fine particle-dispersed film. By heating, the polymerization reaction of titanoxane further progresses, and a titanoxane-containing film is formed.

[0074] The heating temperature is preferably 150 to 400° C., more preferably 200 to 300° C., and even more preferably 250 to 300° C. The heating time varies depending on the heating temperature, but is preferably 1 to 5 hours, more preferably 1 to 3 hours, and even more preferably 1 to 2 hours.

[0075] Next, the titanoxane-containing film will be described. The titanoxane-containing film is a film containing titanoxane.

[0076] The titanoxane is as described above. As described above, the content of the titanium alkoxide condensate in 100% by mass of titanoxane is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and may be 100% by mass.

[0077] The titanoxane-containing film may contain, in addition to titanoxane, for example, a surfactant, etc. These may be used alone or in combination of two or more kinds.

[0078] The content of titanoxane in 100% by mass of the titanoxane-containing film is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and may even be 100% by mass. Within this range, a higher refractive index tends to be obtained.

[0079] The thickness of the titanoxane-containing film is not particularly limited, and is, for example, 10 nm to 1000 nm.

[0080] The smaller the arithmetic mean roughness (Ra) of the titanoxane-containing film, the better, and it is 5 nm or less, more preferably 4 nm or less, and even more preferably 3 nm or less. The lower limit is not particularly limited, but is, for example, 0.5 nm or more. In this specification, the arithmetic mean roughness (Ra) of the film is measured by the method described in the Examples. Note that, the arithmetic mean roughness (Ra) of the titanoxane-containing film being 5 nm or less means that the arithmetic mean roughness (Ra) of the surface of the titanoxane-containing film located on the opposite side to the microparticle-dispersed film (the upper side in Figure 1) is 5 nm or less.

[0081] The method for producing a high refractive index film according to the present disclosure may include other steps in addition to the step of forming a fine particle-dispersed film, the wet treatment step, and the step of forming a titanoxane-containing film. Examples of the other steps include photolithography (exposure and development), etching, imprinting, etc. One or more of these steps may be repeated.

[0082] <High refractive index film> The high refractive index film of the present disclosure has a microparticle-dispersed film containing metal oxide microparticles and a titanoxane-containing film on the microparticle-dispersed film, and the titanoxane-containing film has an arithmetic average roughness (Ra) of 5 nm or less. The microparticle-dispersed film and the titanoxane-containing film are as already described in the manufacturing method of the high refractive index film of the present disclosure. The high refractive index film of the present disclosure has a high refractive index titanoxane-containing film on a microparticle-dispersed film with a high refractive index, and therefore has the advantage of having a higher refractive index as a laminate (high refractive index film) compared to a case where a low refractive index resin film is on a microparticle-dispersed film with a high refractive index.

[0083] The refractive index of the high refractive index film of the present disclosure at 633 nm (25°C) is preferably 1.8 or more, more preferably 1.9 or more, and particularly preferably 2.0 or more, and the upper limit is not particularly limited, but is, for example, 2.5 or less. In this specification, the refractive index of the film is measured by the method described in the Examples. In addition, in this specification, the high refractive index film means a film whose refractive index is within the above-mentioned preferred numerical range.

[0084] The thickness of the high refractive index film of the present disclosure is not particularly limited, and is, for example, 100 nm to 10 μm.

[0085] FIG. 1 is a cross-sectional view schematically illustrating an example of a high-refractive-index film according to the present disclosure. The high-refractive-index film 10 includes a microparticle-dispersed film 1 containing metal oxide microparticles and a titanoxane-containing film 2 laminated in this order toward one side in the thickness direction. The microparticle-dispersed film 1 and the titanoxane-containing film 2 each have a shape that extends in a direction (plane direction) perpendicular to the thickness direction. Thus, the high-refractive-index film 10 includes the titanoxane-containing film 2 on one main surface of the microparticle-dispersed film 1. In this specification, the main surface of the film refers to the surface having the largest area among the surfaces of the film.

[0086] The high refractive index film of the present disclosure can be formed into any shape, such as a dome shape or a sheet shape, depending on the application.

[0087] <Uses of high refractive index film> Because the high refractive index film of the present disclosure has a high refractive index, it is used in optical components such as semiconductor lasers, lenses, optical filters, protective layers, encapsulants, light-emitting elements, reflective films, transmissive films, and anti-reflection films. Among optical components, light-emitting elements are preferred, and light-emitting elements for light extraction are more preferred. The light-emitting element is not particularly limited, and examples thereof include LEDs (light-emitting diodes), LDs (laser diodes), and ELs (electroluminescence).

[0088] <Optical Element> The optical element of the present disclosure has the high refractive index film of the present disclosure. The optical element of the present disclosure is not particularly limited as long as it has the high refractive index film of the present disclosure. The method for manufacturing the optical element of the present disclosure is not particularly limited as long as it includes a step of manufacturing a high refractive index film by the method for manufacturing a high refractive index film of the present disclosure. A person skilled in the art can perform the step of manufacturing a high refractive index film by the method for manufacturing a high refractive index film of the present disclosure, and then manufacture an optical element by a known method or the like using the manufactured high refractive index film of the present disclosure. Furthermore, a person skilled in the art can appropriately incorporate the step of manufacturing a high refractive index film by the method for manufacturing a high refractive index film of the present disclosure into the manufacturing process of the optical element. The optical element is as described above.

[0089] As an example of an optical component according to the present disclosure, a brief description will be given of an embodiment in which the high refractive index film according to the present disclosure is used as a light extraction film for extracting light to the outside of a light emitting device (e.g., into the atmosphere). The high refractive index film according to the present disclosure is applied to a light emitting device in the same manner as a light extraction film, which is a high refractive index layer, is disposed between a substrate and a transparent electrode in a typical light emitting device.

[0090] The high-refractive index film of the present disclosure may have a light-scattering structure or a diffraction grating with a concave-convex shape at the interface with the substrate. For example, after forming a diffraction grating on a substrate by a nanoimprinting method, the diffraction grating with a concave-convex shape can be provided at the interface by laminating a high-refractive index film on the surface of the substrate on which the diffraction grating has been formed. Alternatively, the light-scattering structure can be provided at the interface by laminating a high-refractive index film on the surface of a substrate to which a light scatterer has been previously attached.

[0091] A light-emitting element, which is an example of an optical component of the present disclosure, includes a light-transmitting substrate and a high-refractive index film of the present disclosure, and the entire light-emitting element is light-transmitting. The light-emitting element is light-transmitting as a whole. Therefore, the high-refractive index layer and the substrate are light-transmitting. Note that if the light-emitting element has an additional structure between the high-refractive index layer and the substrate, the additional structure is necessarily selected from structures that are light-transmitting. "Light-transmitting as a whole" means that all layers constituting the light-emitting element transmit light in the stacking direction. Here, the light-emitting element only needs to be light-transmitting in a portion of the surface direction, and does not need to be light-transmitting in the entire surface direction. In this specification, "light-transmitting" means that the transmittance at a wavelength of 450 nm is 90% or more.

[0092] FIG. 2 is a cross-sectional view schematically illustrating an example of an optical member according to the present disclosure. As shown in FIG. 2 , the light-emitting element 100 includes, in order from the bottom, a substrate 21, a high-refractive index film 10, a transparent electrode 22, an organic layer 23, and a cathode 24. The light-emitting element 100 has a similar configuration to a bottom-emission light-emitting element, except that it further includes a high-refractive index film 10 between the substrate 21 and the transparent electrode 22. The light-emitting element 100 is an organic electroluminescent (OLED) element that emits light based on current injection light emission, and can also be called a self-luminous thin-film element. Such a light-emitting element 100 is excellent as a surface light source and is primarily suitable as a light source for illumination. While an OLED is described here as a specific example of a light-emitting element, the light-emitting element may also be a light-emitting element (e.g., another LED) whose light extraction efficiency can be improved by applying the light extraction film described above.

[0093] The high-refractive-index film 10 has a refractive index higher than that of the transparent electrode 22 serving as a cathode. An example of a material for the transparent electrode 22 is an ITO layer (refractive index: n = 1.90), but any material may be used as long as it has the conductivity and optical transparency required for a cathode and a refractive index lower than that of the high-refractive-index film 10. Here, an ITO layer is used as an example of the transparent electrode 22, and no particular mention is made of a case where the refractive indexes of the high-refractive-index film 10 and the transparent electrode 22 are the same. However, in order for the high-refractive-index film 10 to function as a light extraction film, it is sufficient that it has a refractive index at least equal to or higher than that of the transparent electrode 22. The transparent electrode 22 made of an ITO layer is typically formed by sputtering or chemical vapor deposition (CVD).

[0094] Although not shown, the organic layer 23 is a multi-layer organic light-emitting layer. The organic light-emitting layer includes at least an electron transport layer and a hole transport layer, and further includes a light-emitting layer in which either the electron transport layer or the hole transport layer is doped with a light-emitting material or which independently contains a light-emitting material. The transport material may also function as the light-emitting material, in which case the organic layer may be composed of two layers. Depending on the materials contained in the electron transport layer and the hole transport layer, an electron injection layer may be formed in contact with the electron transport layer, and a hole injection layer may be formed in contact with the hole transport layer, as necessary.

[0095] The hole transport material, electron transport material, and light emitting material are known to those skilled in the art and will not be described in detail. As representative examples of each, the hole transport material may be an aromatic amine compound such as N,N-di(naphthylene-1-yl)-N,N-diphenyl-benzidene (NPB), and the electron transport material may be Tris(8-quinolinolate)aluminum (Alq ３ ), oxadiazoles such as 2-biphenyl-5-(4-t-butylphenyl)1,3,5-oxadiazole (PBD), or triazoles such as 3-phenyl-4(1-naphthyl)-5-phenyl-1,2,4-triazole (TAZ). The light-emitting material is Alq ３ Depending on the material, each layer is formed by vapor deposition, inkjet printing, or the like.

[0096] Examples that more specifically disclose embodiments of the present disclosure are given below, but the present disclosure is not limited to these examples.

[0097] The following initiators were used: Omnirad 907d: a compound having the following structure, a photoradical initiator

[0098] [D50 of Metal Oxide Fine Particles] The D50 of metal oxide fine particles means the median diameter (median value) when each particle is considered as a sphere (based on scattering intensity in dynamic light scattering), and is a statistical value calculated such that half of the particles are above this value and the remaining half are below this value. Specifically, a particle dispersion is diluted with propylene glycol monomethyl ether to a particle concentration of 0.1% by mass, and the particle size distribution is measured at 25 ° C. by dynamic light scattering using a particle size measurement system ELSZneoSE manufactured by Otsuka Electronics Co., Ltd., and the particle diameter at which the cumulative particle size distribution based on the number of particles reaches 50% after 25 integrations is taken as D50.

[0099] [Method for measuring solid content concentration] The chemical solution is placed in an aluminum cup, and the mass of the chemical solution added at this time is recorded. The aluminum cup is placed on a hot plate heated to 250°C for 3 minutes, and the mass of the remaining chemical solution on the aluminum cup is then measured. The solid content concentration is determined by dividing the remaining mass by the mass of the chemical solution added.

[0100] [Film Thickness Measurement Method] The film thickness was measured by scraping a part of the coating film down to the substrate with a spatula and observing the step between the substrate and the top of the coating film with a micro-profile measuring instrument ET200A-D manufactured by Kosaka Laboratory Co., Ltd.

[0101] [Refractive index measurement method] The refractive index was measured by analyzing the reflection spectrum using a microspectrophotometric film thickness meter OPTM manufactured by Otsuka Electronics Co., Ltd. During the analysis, the film thickness measured with the microprofile measuring instrument was used as a film thickness parameter, and the refractive index dispersion equation for the visible light range was calculated by fitting the reflection spectrum to the Tauc-Lorenz dispersion equation, and the refractive index value at a wavelength of 633 nm was extracted from this dispersion equation and used as a representative value. The measurement temperature was 25°C.

[0102] [Method for confirming the presence of metal oxide fine particles in the film] Whether or not metal oxide fine particles were present in the film after the second step described below was confirmed by observing the cross section of the coated film using a 20 keV backscattered electron microscope JSM-IT800 manufactured by JEOL Ltd. In addition, the particles were confirmed to be the added metal oxide using an attached EDS (Gather-X manufactured by JEOL Ltd.).

[0103] [Method for Confirming the Presence of Titanoxane Bonds on the Outermost Surface of the Film] Whether or not titanoxane bonds are present on the outermost surface of the film after the second step described below was confirmed by comparing the spectral information described in JP 2000-86769 A with the infrared spectrum of the coating film (measured using a Fourier transform infrared spectrophotometer Nicolet Summit manufactured by Thermo Fisher Scientific K.K., ATR (Attenuated Total Reflection) method, by cutting the substrate and pressing it against a germanium stand), and confirming that the shapes matched.

[0104] [Method for evaluating the smoothness of the outermost surface of the film] The smoothness of the outermost surface of the film after the second step described below was confirmed by measuring the arithmetic mean roughness (Ra) of the film using an atomic force microscope in dynamic mode, using an SMP-9700 manufactured by Shimadzu Corporation and an OCCL-AC200TS-C3 probe manufactured by Olympus Corporation. When Ra was 5 nm or less, the smoothness was rated as ○, and when Ra was more than 5 nm, it was rated as ×. The measurement conditions were in accordance with JIS R 1683:2014.

[0105] [Method for Evaluating Film Transmittance] The transmittance of a film formed on an alkali-free glass substrate after the second step described below was measured at wavelengths of 350 nm to 800 nm using an ultraviolet-visible-near-infrared spectrophotometer U4100 manufactured by Hitachi High-Tech Corp., with air as the background. A transmittance of 90% or more at a wavelength of 450 nm was evaluated as "○", and a transmittance of less than 90% was evaluated as "×".

[0106] [Preparation of titanoxane chemical solution] 12.0 g of ethanol, 0.32 g (18 mmol) of water, 0.28 g (2.4 mmol) of maleic acid, and 4.69 g (36 mmol) of ethyl acetoacetate were added to a 200 ml flask and mixed at room temperature. A mixture of 11.65 g (34 mmol) of titanium tetrabutoxide and 36 g of ethanol was added with stirring. The flask was heated to 70°C and stirred for 24 hours. 40 g of propylene glycol monomethyl ether (PGME) was then added, and the mixture was concentrated to remove ethanol and unreacted water. This yielded 47 g of titanoxane chemical solution with a solids concentration of 15% by mass. The presence of titanoxane bonds in the chemical solution was confirmed by comparing the spectral information described in JP 2000-86769 A with the infrared spectrum of the chemical solution (measured using a Fourier transform infrared spectrophotometer Nicolet Summit manufactured by Thermo Fisher Scientific K.K., ATR method, by dropping the chemical solution onto a germanium base) and finding that the shapes matched (this was also confirmed hereinafter).

[0107] [Preparation of titanoxane / siloxane chemical solution] 12.0 g of ethanol, 1.27 g (71 mmol) of water, 0.28 g (2.4 mmol) of maleic acid, and 13.76 g (106 mmol) of ethyl acetoacetate were added to a 200 ml flask and mixed at room temperature. A mixture of 11.99 g (35 mmol) of titanium tetrabutoxide, 2.82 g (11.8 mmol) of triethoxyphenylsilane, and 36 g of ethanol was added thereto with stirring. The flask was heated to 70°C and stirred for 24 hours. 40 g of PGME was then added, and the mixture was concentrated to remove ethanol and unreacted water. This yielded 50 g of titanoxane / siloxane chemical solution, which was a solution with a solids concentration of 15% by mass. The presence of siloxane bonds in the chemical solution was confirmed by the 1010 cm stretching vibration of the silicon-oxygen bond. －１ The results were confirmed by infrared spectroscopy using the ATR method (measurement was performed by dropping the chemical solution onto a germanium stage) using the above as an index (confirmation was performed in the same manner hereafter).

[0108] [Preparation of Siloxane Chemical Solution] 12.0 g of ethanol, 1.8 g (100 mmol) of water, and 0.3 g (5 mmol) of acetic acid were added to a 200 ml flask and mixed at room temperature. A mixture of 12 g (50 mmol) of triethoxyphenylsilane and 36 g of ethanol was added thereto with stirring. The flask was heated to 70°C and stirred for 24 hours. 100 g of diisopropyl ether was then added, and the mixture was washed three times with 100 g of water. 40 g of PGME was added to the resulting organic layer, and the mixture was concentrated to remove the ethanol and diisopropyl ether. This yielded 45 g of a siloxane chemical solution with a solids concentration of 15% by mass.

[0109] [Preparation of Wet Treatment Liquid 1 Used in Step 2 Described Below] 6.67 g of PGME and 3.33 g of the titanoxane solution were added to a 30 ml vial and stirred until homogenous, to obtain Wet Treatment Liquid 1 (5% by mass of titanoxane).

[0110] [Preparation of Wet Treatment Liquid 2 Used in Second Step Described Below] 3.33 g of PGME and 6.67 g of the titanoxane solution were added to a 30 ml vial and stirred until homogenous, to obtain Wet Treatment Liquid 2 (10% by mass of titanoxane).

[0111] [Preparation of Wet Treatment Liquid 3 to be Used in the Second Step Described Below] The titanoxane solution was used as it was as wet treatment liquid 3 (titanoxane 15% by mass).

[0112] [Preparation of Wet Treatment Liquid 4 to be Used in the Second Step Described Below] The titanoxane / siloxane chemical solution was used as it was as wet treatment liquid 4 (titanoxane / siloxane 15% by mass).

[0113] [Preparation of Resin Solution 1 Used in Resin Solution Treatment of Microparticle Dispersion Film] 9 g of PGME, 1 g of dipentaerythritol hexaacrylate (DPHA), and 0.05 g of Omnirad 907d were added to a 30 ml vial and stirred until homogenous to obtain Resin Solution 1 (referred to simply as "Acrylic" in the table, DPHA 10% by mass).

[0114] [Formation of fine particle dispersion film 1 (first step)] (titanoxane / titania fine particles=15 / 85 (mass / mass)) 2.5 g of a titanium oxide fine particle dispersion liquid (LDB-142-35, rutile crystal, particle diameter D50=29 nm, solid content 35 mass%) manufactured by Ishihara Sangyo Kaisha, Ltd., 0.97 g of the above titanoxane chemical solution, and 6.2 g of PGME were added to a 30 ml vial, and the mixture was stirred at 80° C. for 1 hour to prepare fine particle dispersion film coating liquid 1. This fine particle dispersion film coating liquid 1 was spin-coated onto a 4-inch silicon wafer at 1000 rpm, and the wafer was heated on a hot plate at 250° C. for 2 hours to form a fine particle dispersion film 1.

[0115] [Formation of Fine Particle Dispersion Film 2 (Step 1)] (DPHA / Titania Fine Particles = 10 / 90 (mass / mass)) 5.06 g of titanium oxide fine particle dispersion liquid (LDB-142-35, rutile crystal, particle diameter D50 = 29 nm, solid content 35 mass%) manufactured by Ishihara Sangyo Kaisha, Ltd., 0.18 g of DPHA, 0.009 g of Omnirad 907d, and 7.2 g of PGME were added to a 30 ml vial and stirred at 80 ° C until uniform, to prepare fine particle dispersion film coating solution 2. This fine particle dispersion film coating solution 2 was spin coated on a 4-inch silicon wafer at 3000 rpm, heated on a 110 ° C hot plate for 3 minutes, and irradiated with light of 365 nm wavelength at 1 J / cm using an LED (manufactured by Ushio Inc.). ２ A fine particle dispersed film 2 was formed by irradiating the light with an exposure amount of 1000 ppm.

[0116] [Formation of fine particle dispersion film 3 (first step)] (siloxane / titania fine particles=10 / 90 (mass / mass)) 2.5 g of a titanium oxide fine particle dispersion liquid (LDB-142-35, rutile crystal, particle diameter D50=29 nm, solid content 35 mass%) manufactured by Ishihara Sangyo Kaisha, Ltd., 0.97 g of the above siloxane chemical solution, and 6.2 g of PGME were added to a 30 ml vial and stirred at 80° C. for 1 hour to prepare fine particle dispersion film coating liquid 3. This fine particle dispersion film coating liquid 3 was spin-coated onto a 4-inch silicon wafer at 1000 rpm, and heated on a hot plate at 250° C. for 2 hours to form a fine particle dispersion film 3.

[0117] [Formation of fine particle dispersion film 4 (first step)] (titanoxane / zirconia fine particles=15 / 85 (mass / mass)) 1.25 g of a zirconium oxide fine particle dispersion liquid (ZP-153, particle diameter D50=11 nm, solid content 70 mass%) manufactured by Nippon Shokubai, 0.97 g of the above titanoxane chemical solution, and 6.2 g of PGME were added to a 30 ml vial and stirred at 80° C. for 1 hour to prepare fine particle dispersion film coating liquid 4. This fine particle dispersion film coating liquid 4 was spin-coated at 1000 rpm onto a 4-inch silicon wafer and heated on a hot plate at 250° C. for 2 hours to form a fine particle dispersion film 4.

[0118] [Formation of Fine Particle Dispersion Film 5 (Step 1)] (DPHA / zirconia fine particles = 10 / 90 (mass / mass)) 2.53 g of a zirconium oxide fine particle dispersion liquid (ZP-153, particle diameter D50 = 11 nm, solid content 70 mass%) manufactured by Nippon Shokubai, 0.18 g of DPHA, 0.009 g of Omnirad 907d, and 7.2 g of PGME were added to a 30 ml vial and stirred at 80°C until uniform to prepare fine particle dispersion film coating solution 5. This fine particle dispersion film coating solution 5 was spin coated on a 4-inch silicon wafer at 3000 rpm, heated on a 110°C hot plate for 3 minutes, and irradiated with light of 365 nm wavelength at 1 J / cm using an LED (manufactured by Ushio Inc.). ２ The fine particle dispersed film 5 was formed by irradiating the light with an exposure amount of 1000 ppm.

[0119] [Formation of fine particle dispersion film 6 (first step)] (titanoxane / niobium oxide fine particles=15 / 85 (mass / mass)) 11.7 g of a niobium oxide fine particle dispersion liquid (Nb-G6000, particle diameter D50=15 nm, solids content 6 mass%) manufactured by Taki Chemical Industry Co., Ltd., 0.97 g of the titanoxane chemical solution, and 6.2 g of PGME were added to a 30 ml vial, and the mixture was concentrated at 50° C. to a solids content of 10 mass % to prepare fine particle dispersion film coating liquid 6. This fine particle dispersion film coating liquid 6 was spin-coated onto a 4-inch silicon wafer at 1000 rpm, and the wafer was heated on a hot plate at 250° C. for 2 hours to form a fine particle dispersion film 6.

[0120] [Formation of Fine Particle Dispersion Film 7 (Step 1)] (DPHA / Niobium Oxide Fine Particles = 10 / 90 (mass / mass)) 29.5 g of niobium oxide fine particle dispersion liquid (Nb-G6000, particle diameter D50 = 15 nm, solid content 6 mass%) manufactured by Taki Chemical Industry Co., Ltd., 0.18 g of DPHA, 0.009 g of Omnirad 907d, and 7.2 g of PGME were added to a 30 ml vial, and the mixture was concentrated at 50 ° C. to a solid content of 10 mass % to prepare fine particle dispersion film coating solution 7. This fine particle dispersion film coating solution 7 was spin coated on a 4-inch silicon wafer at 3000 rpm, heated on a 110 ° C. hot plate for 3 minutes, and 1 J / cm of light with a wavelength of 365 nm was applied using an LED (manufactured by Ushio Inc.). ２ The fine particle dispersed film 7 was formed by irradiating the light with an exposure amount of 1000 ppm.

[0121] [Formation of fine particle dispersion film 8 (first step)] (titanoxane / cerium oxide fine particles=15 / 85 (mass / mass)) 7.0 g of a cerium oxide fine particle dispersion liquid (B-10, particle diameter D50=20 nm, solids content 10 mass%) manufactured by Taki Chemical Industry Co., Ltd., 0.97 g of the titanoxane chemical solution, and 6.2 g of PGME were added to a 30 ml vial, and the mixture was concentrated at 50° C. to a solids content of 10 mass % to prepare fine particle dispersion film coating liquid 8. This fine particle dispersion film coating liquid 8 was spin-coated onto a 4-inch silicon wafer at 1000 rpm, and the wafer was heated on a hot plate at 250° C. for 2 hours to form a fine particle dispersion film 8.

[0122] [Formation of Fine Particle Dispersion Film 9 (Step 1)] (DPHA / Cerium Oxide Fine Particles = 10 / 90 (mass / mass)) 17.7 g of cerium oxide fine particle dispersion liquid (B-10, particle diameter D50 = 20 nm, solid content 10 mass%) manufactured by Taki Chemical Industry, 0.18 g of DPHA, 0.009 g of Omnirad 907d, and 7.2 g of PGME were added to a 30 ml vial and concentrated at 50°C to a solid content of 10 mass% to prepare fine particle dispersion film coating solution 9. This fine particle dispersion film coating solution 9 was spin coated on a 4-inch silicon wafer at 3000 rpm, heated on a 110°C hot plate for 3 minutes, and irradiated with light of 365 nm wavelength at 1 J / cm using an LED (manufactured by Ushio Inc.). ２ The fine particle dispersed film 9 was formed by irradiating the light with an exposure amount of 1000 ppm.

[0123] [Formation of fine particle dispersion film 10 (first step)] (Titanoxane / zinc oxide fine particles=15 / 85 (mass / mass)) 0.82 g of zinc oxide fine particle powder (FZO-50, particle diameter D50=21 nm) manufactured by Ishihara Sangyo Kaisha, Ltd., 0.97 g of the above titanoxane solution, and 6.2 g of PGME were added to a 30 ml vial and stirred at 80° C. for 1 hour to prepare a fine particle dispersion film coating solution 10. This fine particle dispersion film coating solution 10 was spin-coated onto a 4-inch silicon wafer at 1000 rpm, and heated on a hot plate at 250° C. for 2 hours to form a fine particle dispersion film 10.

[0124] [Formation of fine particle dispersion film 11 (first step)] (DPHA / zinc oxide fine particles = 10 / 90 (mass / mass)) 1.8 g of zinc oxide fine particle powder (FZO-50, particle diameter D50 = 21 nm) manufactured by Ishihara Sangyo Kaisha, Ltd., 0.18 g of DPHA, 0.009 g of Omnirad 907d, and 7.2 g of PGME were added to a 30 ml vial and stirred at 80°C until uniform to prepare fine particle dispersion film coating solution 11. This fine particle dispersion film coating solution 11 was spin-coated onto a 4-inch silicon wafer at 3000 rpm, heated on a 110°C hot plate for 3 minutes, and irradiated with light of 365 nm wavelength at 1 J / cm using an LED (manufactured by Ushio Inc.). ２ The fine particle dispersed film 11 was formed by irradiating the light with an exposure amount of 1000 ppm.

[0125] [Example 1 (Second Step)] The fine particle dispersion film 1 was subjected to UV / ozone treatment (low-pressure mercury lamp, 5 minutes, surface modification device manufactured by Sen Special Light Sources), and the wet treatment liquid 1 was spin-coated thereon at 2000 rpm. This film was heated on a hot plate at 250°C for 2 hours to form film 1 after the second step. The refractive index of film 1 after the second step was measured by the above-mentioned method. The results are shown in Table 1 together with other evaluation results.

[0126] [Example 2 (Second Step)] The fine particle dispersion film 1 was subjected to UV / ozone treatment (low-pressure mercury lamp, 5 minutes, surface modification device manufactured by Sen Special Light Sources), and the wet treatment liquid 2 was spin-coated thereon at 2000 rpm. This film was heated on a hot plate at 250°C for 2 hours to form film 2 after the second step. The refractive index of film 2 after the second step was measured by the above-mentioned method. The results are shown in Table 1 together with other evaluation results.

[0127] [Example 3 (Second Step)] The fine particle dispersion film 1 was subjected to UV / ozone treatment (low-pressure mercury lamp, 5 minutes, surface modification device manufactured by Sen Special Light Sources), and the wet treatment liquid 3 was spin-coated thereon at 4000 rpm. This film was heated on a hot plate at 250°C for 2 hours to form film 3 after the second step. The refractive index of film 3 after the second step was measured by the above-mentioned method. The results are shown in Table 1 together with other evaluation results.

[0128] Example 4 (Second Process) The fine particle dispersion film 2 was subjected to UV / ozone treatment (low-pressure mercury lamp, 5 minutes, surface modification device manufactured by Sen Special Light Sources), and the wet treatment solution 3 was spin-coated thereon at 4000 rpm. This film was heated on a hot plate at 250°C for 2 hours to form a film 4 after the second process. The refractive index of the film 4 after the second process was measured by the above-mentioned method. The results are shown in Table 1 together with other evaluation results.

[0129] Example 5 (Second Process) The fine particle dispersion film 1 was subjected to UV / ozone treatment (low-pressure mercury lamp, 5 minutes, surface modification device manufactured by Sen Special Light Sources), and the wet treatment liquid 4 was spin-coated thereon at 4000 rpm. This film was heated on a hot plate at 250°C for 2 hours to form film 5 after the second process. The refractive index of film 5 after the second process was measured by the above-mentioned method. The results are shown in Table 1 together with other evaluation results.

[0130] Example 6 (Second Process) The fine particle dispersion film 3 was subjected to UV / ozone treatment (low-pressure mercury lamp, 5 minutes, surface modification device manufactured by Sen Special Light Sources), and the wet treatment liquid 3 was spin-coated thereon at 4000 rpm. This film was heated on a hot plate at 250°C for 2 hours to form a film 6 after the second process. The refractive index of the film 6 after the second process was measured by the above-mentioned method. The results are shown in Table 1 together with other evaluation results.

[0131] Example 7 (Second Process) The fine particle dispersion film 4 was subjected to UV / ozone treatment (low-pressure mercury lamp, 5 minutes, surface modification device manufactured by Sen Special Light Sources), and the wet treatment solution 3 was spin-coated thereon at 4000 rpm. This film was heated on a hot plate at 250°C for 2 hours to form film 7 after the second process. The refractive index of film 7 after the second process was measured by the above-mentioned method. The results are shown in Table 1 together with other evaluation results.

[0132] Example 8 (Second Process) The fine particle dispersion film 5 was subjected to UV / ozone treatment (low-pressure mercury lamp, 5 minutes, surface modification device manufactured by Sen Special Light Sources), and the wet treatment liquid 3 was spin-coated thereon at 4000 rpm. This film was heated on a hot plate at 250°C for 2 hours to form a film 8 after the second process. The refractive index of the film 8 after the second process was measured by the above-mentioned method. The results are shown in Table 1 together with other evaluation results.

[0133] Example 9 (Second Process) The fine particle dispersion film 6 was subjected to UV / ozone treatment (low-pressure mercury lamp, 5 minutes, surface modification device manufactured by Sen Special Light Sources), and the wet treatment solution 3 was spin-coated thereon at 4000 rpm. This film was heated on a hot plate at 250°C for 2 hours to form a film 9 after the second process. The refractive index of the film 9 after the second process was measured by the above-mentioned method. The results are shown in Table 1 together with other evaluation results.

[0134] Example 10 (Second Process) The fine particle dispersion film 7 was subjected to UV / ozone treatment (low-pressure mercury lamp, 5 minutes, surface modification device manufactured by Sen Special Light Sources), and the wet treatment solution 3 was spin-coated thereon at 4000 rpm. This film was heated on a hot plate at 250°C for 2 hours to form a film 10 after the second process. The refractive index of the film 10 after the second process was measured by the above-mentioned method. The results are shown in Table 1 together with other evaluation results.

[0135] Example 11 (Second Step) The fine particle dispersion film 8 was subjected to UV / ozone treatment (low-pressure mercury lamp, 5 minutes, surface modification device manufactured by Sen Special Light Sources), and the wet treatment solution 3 was spin-coated thereon at 4000 rpm. This film was heated on a hot plate at 250°C for 2 hours to form a film 11 after the second step. The refractive index of the film 11 after the second step was measured by the above-mentioned method. The results are shown in Table 1 together with other evaluation results.

[0136] Example 12 (Second Process) The fine particle dispersion film 9 was subjected to UV / ozone treatment (low-pressure mercury lamp, 5 minutes, surface modification device manufactured by Sen Special Light Sources), and the wet treatment liquid 3 was spin-coated thereon at 4000 rpm. This film was heated on a hot plate at 250°C for 2 hours to form a film 12 after the second process. The refractive index of the film 12 after the second process was measured by the above-mentioned method. The results are shown in Table 1 together with other evaluation results.

[0137] Example 13 (Second Process) The fine particle dispersion film 10 was subjected to UV / ozone treatment (low-pressure mercury lamp, 5 minutes, surface modification device manufactured by Sen Special Light Sources), and the wet treatment solution 3 was spin-coated thereon at 4000 rpm. This film was heated on a hot plate at 250°C for 2 hours to form a film 13 after the second process. The refractive index of the film 13 after the second process was measured by the above-mentioned method. The results are shown in Table 1 together with other evaluation results.

[0138] Example 14 (Second Process) The fine particle dispersion film 11 was subjected to UV / ozone treatment (low-pressure mercury lamp, 5 minutes, surface modification device manufactured by Sen Special Light Sources), and the wet treatment solution 3 was spin-coated thereon at 4000 rpm. This film was heated on a hot plate at 250°C for 2 hours to form a film 14 after the second process. The refractive index of the film 14 after the second process was measured by the above-mentioned method. The results are shown in Table 1 together with other evaluation results.

[0139] Comparative Example 1 (Resin Solution Treatment of Fine Particle-Dispersed Film) The fine particle-dispersed film 11 was subjected to UV / ozone treatment (low-pressure mercury lamp, 5 minutes, surface modification device manufactured by Sen Special Light Sources), and the resin solution 1 was spin-coated thereon at 4000 rpm. This film was heated on a hot plate at 110°C for 3 minutes, and light of 365 nm wavelength was applied at 1 J / cm using an LED (manufactured by Ushio Inc.). ２ The refractive index of the film 15 after the resin solution treatment was measured by the above-mentioned method. The results are shown in Table 1 together with other evaluation results.

[0140] Reference Example 1 (ALD Treatment of Fine Particle-Dispersed Film) The fine particle-dispersed film 2 was subjected to UV / ozone treatment (low-pressure mercury lamp, 5 minutes, surface modification device manufactured by Sen Special Light Sources), and then titania was deposited on the fine particle-dispersed film 2 by the ALD method (ALD device AL-1 manufactured by Samco, titanium isopropoxide and water were alternately introduced into the chamber, repeated 15 cycles) to obtain a film 16 after the titania ALD treatment. The refractive index of the film 16 after the titania ALD treatment was measured by the above-mentioned method. The results are shown in Table 1 together with other evaluation results.

[0141]

[0142] As shown in Table 1, wet treatment with titanoxane solution improves the refractive index to a greater extent than wet treatment with an acrylic material. This indicates that wet treatment of a microparticle-dispersed film with a solution containing titanoxane is effective in improving the refractive index. Furthermore, using a microparticle-dispersed film with a high refractive index is effective in increasing the refractive index of the final film (laminate).

[0143] From Table 1, it is clear that the method for producing a high refractive index film of the present disclosure, which includes a microparticle dispersion film formation step of forming a microparticle dispersion film containing metal oxide microparticles and a wet treatment step of applying a liquid containing titanoxane onto the microparticle dispersion film formed by the microparticle dispersion film formation step, can provide a method for producing a high refractive index film that can improve the refractive index by wet treatment, and a method for producing an optical component having a high refractive index film.

[0144] DESCRIPTION OF SYMBOLS 1 Fine particle dispersion film containing metal oxide fine particles 2 Titanoxane-containing film 10 High refractive index film 21 Substrate 22 Transparent electrode 23 Organic layer 24 Cathode 100 Light-emitting element

Claims

1. A method for manufacturing a high refractive index film, comprising: a fine particle dispersion film forming step of forming a fine particle dispersion film containing metal oxide fine particles; and a wet processing step of applying a liquid containing titanoxane onto the fine particle dispersion film formed in the fine particle dispersion film forming step.

2. The method for producing a high refractive index film according to claim 1, wherein the fine particle dispersed film contains metal oxide fine particles and a resin.

3. The method for producing a high refractive index film according to claim 1, wherein the metal oxide is at least one selected from the group consisting of titanium oxide, zirconium oxide, niobium oxide, cerium oxide, zinc oxide, indium oxide, tin oxide, indium tin oxide, and antimony oxide.

4. The method for producing a high refractive index film according to claim 1, wherein the metal oxide is at least one selected from the group consisting of titanium oxide, zirconium oxide, niobium oxide, cerium oxide and zinc oxide.

5. The method for producing a high refractive index film according to claim 1, wherein the metal oxide is at least one selected from the group consisting of titanium oxide, zirconium oxide and niobium oxide.

6. A method for producing a high refractive index film according to claim 1, further comprising a titanoxane-containing film-forming step of forming a titanoxane-containing film on the fine particle dispersion film by heating after the wet treatment step.

7. The method for producing a high refractive index film according to claim 1, wherein the content of titanoxane in 100% by mass of the liquid containing titanoxane is 1 to 20% by mass.

8. A method for producing an optical element having a high refractive index film, comprising the step of producing a high refractive index film by the method for producing a high refractive index film according to any one of claims 1 to 7.

9. The method for producing an optical member according to claim 8, wherein the optical member is a light-emitting element.

10. A high refractive index film comprising: a fine particle dispersion film containing metal oxide fine particles; and a titanoxane-containing film on the fine particle dispersion film, wherein the arithmetic mean roughness (Ra) of the titanoxane-containing film is 5 nm or less.

11. The high refractive index film according to claim 10, wherein the metal oxide is at least one selected from the group consisting of titanium oxide, zirconium oxide, niobium oxide, cerium oxide, zinc oxide, indium oxide, tin oxide, indium tin oxide, and antimony oxide.

12. The high refractive index film according to claim 10, wherein the metal oxide is at least one selected from the group consisting of titanium oxide, zirconium oxide, niobium oxide, cerium oxide and zinc oxide.

13. The high refractive index film according to claim 10, wherein said metal oxide is at least one selected from the group consisting of titanium oxide, zirconium oxide and niobium oxide.

14. An optical element having a high refractive index film according to any one of claims 10 to 13.

15. The optical element according to claim 14, which is a light-emitting element.

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