Optical film with antisoiling layer

Abstract

The optical film (F) of the present application is an optical film with a stain-proof layer, which comprises, in order, a transparent substrate (10), an optical functional layer (20), and a stain-proof layer (30). The outer surface (31) on the side opposite to the optical functional layer (20) of the stain-proof layer (30) has a water contact angle of 110° or more.

Description

Technical Field

[0001] This invention relates to optical thin films with anti-fouling layers. Background Technology

[0002] A transparent optical film is provided on the outer surface of the image display side of a display such as a liquid crystal display (LCD). This optical film includes a layer (optical functional layer) having a defined optical function. Examples of optical films include anti-reflective films, transparent conductive films, and electromagnetic wave shielding films. The optical film includes, for example, a transparent substrate, an optical functional layer disposed on one side thereon, and an adhesive layer disposed on the other side of the transparent substrate. Related technology for such optical films is described, for example, in Patent Document 1 below.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-227898 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] In optical films where an optical functional layer is configured as the outermost layer, contaminants such as hand oils easily adhere to this layer, and it is difficult to remove these contaminants. From the viewpoint of ensuring the transparency of the optical film, contaminant adhesion to the optical film is undesirable. Therefore, an anti-fouling layer, for example, is provided on the optical film as the outermost layer. In such optical films with an anti-fouling layer, high anti-fouling performance is required for the anti-fouling layer.

[0008] The present invention provides an optical thin film with an antifouling layer suitable for achieving high antifouling properties.

[0009] Solution for solving the problem

[0010] The present invention [1] includes an optical film with an antifouling layer, which sequentially comprises a transparent substrate, an optical functional layer and an antifouling layer, wherein the outer surface of the antifouling layer opposite to the optical functional layer has a water contact angle of more than 110°.

[0011] The present invention [2] includes the optical film with anti-fouling layer described in [1] above, wherein the aforementioned outer surface has a surface roughness Ra of more than 2 nm.

[0012] The present invention [3] includes the optical thin film with anti-fouling layer described in [1] or [2] above, wherein the optical functional layer is an anti-reflective layer.

[0013] The present invention [4] includes the optical thin film with anti-fouling layer described above [3], wherein the anti-reflective layer alternately comprises a high refractive index layer with a relatively large refractive index and a low refractive index layer with a relatively small refractive index.

[0014] The present invention [5] includes an optical film with an anti-fouling layer as described in any one of [1] to [4] above, wherein the transparent substrate has a hard coating on the optical functional layer side.

[0015] The present invention [6] includes the optical film with antifouling layer described above [5], wherein the hard coating contains metal oxide particles.

[0016] The present invention [7] includes the optical thin film with anti-fouling layer described above [6], wherein the metal oxide particles are nano-silica particles.

[0017] The present invention [8] includes an optical thin film with an anti-fouling layer as described in any one of [5] to [7] above, wherein the surface of the optical functional layer side of the hard coating has a surface roughness Ra of 0.5 nm or more and 20 nm or less.

[0018] The effects of the invention

[0019] The optical film with antifouling layer of the present invention is suitable for achieving high antifouling performance because the outer surface of the antifouling layer on the opposite side of the optical functional layer has a water contact angle of more than 110°. Attached Figure Description

[0020] Figure 1 This is a cross-sectional schematic diagram of one embodiment of the optical thin film of the present invention.

[0021] Figure 2 This is a cross-sectional schematic diagram of a modified example of the optical thin film of the present invention (in this modified example, the optical thin film includes an adhesive layer). Detailed Implementation

[0022] As one embodiment of the optical thin film with anti-fouling layer of the present invention, the optical thin film F is as follows: Figure 1 As shown, a transparent substrate 10, an optical functional layer 20, and an anti-fouling layer 30 are sequentially provided on the side facing the thickness direction D. In this embodiment, the optical film F is provided with a transparent substrate 10, an adhesive layer 40, an optical functional layer 20, and an anti-fouling layer 30 sequentially on the side facing the thickness direction D, and preferably consists of a transparent substrate 10, an adhesive layer 40, an optical functional layer 20, and an anti-fouling layer 30. Furthermore, the optical film F has a shape that extends in a direction orthogonal to the thickness direction D (planar direction).

[0023] In this embodiment, the transparent substrate 10 has a resin film 11 and a hard coating 12 sequentially on the side facing the thickness direction D.

[0024] The resin film 11 is a flexible, transparent resin film. Examples of materials used for the resin film 11 include polyester resins, polyolefin resins, polystyrene resins, acrylic resins, polycarbonate resins, polyethersulfone resins, polysulfone resins, polyamide resins, polyimide resins, cellulose resins, norbornene resins, polyarylate resins, and polyvinyl alcohol resins. Examples of polyester resins include polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate. Examples of polyolefin resins include polyethylene, polypropylene, and cyclic olefin polymers. Examples of cellulose resins include cellulose triacetate. These materials can be used alone or in combination of two or more. From the viewpoint of transparency and strength, cellulose resins are preferred as materials for the resin film 11, and cellulose triacetate is more preferred.

[0025] The hard coating 12 side surface of the resin film 11 may be subjected to surface modification treatment. Examples of surface modification treatments include corona treatment, plasma treatment, ozone treatment, primer treatment, glow discharge treatment, and coupling agent treatment.

[0026] From the viewpoint of strength, the thickness of the resin film 11 is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 20 μm or more. From the viewpoint of processability, the thickness of the resin film 11 is preferably 300 μm or less, more preferably 200 μm or less.

[0027] From the viewpoint of transparency, the visible light transmittance of the resin film 11 is preferably 80% or more, more preferably 90% or more. The visible light transmittance of the resin film 11 is, for example, 100% or less.

[0028] The hard coating 12 can be disposed on one side of the resin film 11 in the thickness direction D. The hard coating 12 is used to expose the optical film F on its exposed surface (in...). Figure 1 The middle layer (the upper surface) is less prone to scratches.

[0029] The hard coating 12 is a cured product of the curable resin composition. Examples of curable resins included in the curable resin composition include polyester resins, acrylic resins, urethane resins, acrylic urethane resins, amide resins, silicone resins, epoxy resins, and melamine resins. These curable resins can be used alone or in combination of two or more. From the viewpoint of ensuring high hardness of the hard coating 12, acrylic resins and / or acrylic urethane resins are preferably used as curable resins.

[0030] Furthermore, examples of curable resin compositions include, for example, UV-curable resin compositions and thermosetting resin compositions. From the viewpoint that curing without high-temperature heating helps improve the manufacturing efficiency of optical thin films F, UV-curable resin compositions are preferred as curable resin compositions. UV-curable resin compositions comprise at least one selected from the group consisting of UV-curable monomers, UV-curable oligomers, and UV-curable polymers. Examples of UV-curable resin compositions include, for instance, the hard coating forming composition described in Japanese Patent Application Publication No. 2016-179686.

[0031] The hard coating 12 can be an anti-glare hard coating (anti-glare hard coating). The hard coating 12 as an anti-glare hard coating is a cured product containing a curable resin (base resin) and microparticles (anti-glare microparticles) for exhibiting anti-glare properties. Examples of anti-glare microparticles include metal oxide microparticles and organic microparticles. Examples of materials that can be used as metal oxide microparticles include silica, alumina, titanium dioxide, zirconium oxide, calcium oxide, tin oxide, indium oxide, cadmium oxide, and antimony oxide. Examples of materials that can be used as organic microparticles include polymethyl methacrylate, silicone, polystyrene, polyurethane, acrylic-styrene copolymers, benzoguanamine, melamine, and polycarbonate. These microparticles can be used alone or in combination of two or more. From the viewpoint of enabling the hard coating 12 to exhibit good anti-glare properties, it is preferable to use at least one selected from the group consisting of nano-silica particles, polymethyl methacrylate particles, and silicone particles as anti-glare microparticles.

[0032] The average particle size is, for example, 10 μm or less, preferably 8 μm or less, and also, for example, 1 nm or more. When nanoparticles are used as microparticles, the average particle size is, for example, 100 nm or less, preferably 70 nm or less, and also, for example, 1 nm or more. The average particle size is determined, for example, based on the particle size distribution obtained by the particle size distribution measurement method in laser scattering, in the form of a D50 value (the median particle size of the cumulative 50%).

[0033] The refractive index of the base resin (after curing) is, for example, 1.46 or more, preferably 1.49 or more, more preferably 1.50 or more, and even more preferably 1.51 or more. The refractive index is, for example, 1.60 or less, preferably 1.59 or less, more preferably 1.58 or less, and even more preferably 1.57 or less.

[0034] The refractive index of the microparticles can be higher or lower than that of the base resin. When the refractive index of the microparticles is higher than that of the base resin, the refractive index of the microparticles is, for example, 1.62 or less, preferably 1.60 or less, more preferably 1.59 or less, and even more preferably 1.50 or less. When the refractive index of the microparticles is lower than that of the base resin, the refractive index of the microparticles is, for example, 1.40 or more, preferably 1.42 or more, and more preferably 1.44 or more.

[0035] The particulate content in the hard coating 12 is preferably 1 part by mass or more, more preferably 3 parts by mass or more, relative to 100 parts by mass of the base resin. The particulate content in the hard coating 12 is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, relative to 100 parts by mass of the base resin.

[0036] From the viewpoint of ensuring the hardness of this layer, the thickness of the hard coating 12 is preferably 0.5 μm or more, more preferably 1 μm or more. The thickness of the hard coating 12 is, for example, 10 μm or less.

[0037] The adhesive layer 40 side surface of the hard coating 12 may undergo surface modification treatment. Examples of surface modification treatments include plasma treatment, corona treatment, ozone treatment, primer treatment, glow treatment, and coupling agent treatment. From the viewpoint of ensuring high adhesion between the hard coating 12 and the adhesive layer 40, the adhesive layer 40 side surface of the hard coating 12 is preferably treated with glow treatment.

[0038] From a strength point of view, the thickness of the transparent substrate 10 is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 20 μm or more. From a processability point of view, the thickness of the transparent substrate 10 is preferably 300 μm or less, more preferably 200 μm or less.

[0039] From the viewpoint of transparency, the visible light transmittance of the transparent substrate 10 is preferably 80% or more, more preferably 90% or more. The visible light transmittance of the transparent substrate 10 is, for example, 100% or less.

[0040] The surface roughness Ra (arithmetic mean surface roughness) of the surface of the optical functional layer 20 side of the transparent substrate 10 (in this embodiment, the surface of the optical functional layer 20 side of the hard coating 12) is preferably 0.5 nm or more, more preferably 0.8 nm or more. This surface roughness Ra is preferably 20 nm or less, more preferably 15 nm or less. The surface roughness Ra is determined, for example, from a 1 μm square observation image based on AFM (atomic force microscopy).

[0041] The adhesive layer 40 is used to ensure the adhesion between the transparent substrate 10 and the optical functional layer 20. The adhesive layer 40 is disposed on one side of the transparent substrate 10 (specifically, the hard coating 12 of the transparent substrate 10 in this embodiment) in the thickness direction D. Examples of materials for the adhesive layer 40 include metals such as silicon, nickel, chromium, aluminum, tin, gold, silver, platinum, zinc, titanium, tungsten, zirconium, and palladium; alloys of two or more of these metals; and oxides of these metals. From the viewpoint of balancing the adhesion to both the organic layer (specifically, the hard coating 12) and the oxide layer (specifically, the first high refractive index layer 21 described later) and the transparency of the adhesive layer 40, silicon oxide (SiOx) or indium tin oxide (ITO) is preferably used as the material for the adhesive layer 40. When using silicon oxide as the material for the adhesive layer 40, SiOx with a lower oxygen content compared to its stoichiometric composition is preferred, and SiOx with an x ​​of 1.2 or more and 1.9 or less is more preferred.

[0042] From the viewpoint of ensuring the adhesion between the transparent substrate 10 and the optical functional layer 20 while taking into account the transparency of the adhesive layer 40, the thickness of the adhesive layer 40 is, for example, 1 nm or more, or, for example, 10 nm or less.

[0043] The optical functional layer 20 is disposed on one side of the adhesive layer 40 in the thickness direction D. In this embodiment, the optical functional layer 20 is an anti-reflective layer for suppressing the intensity of external light reflection. That is, the optical thin film F is an anti-reflective film in this embodiment.

[0044] The optical functional layer 20 (anti-reflective layer) alternately comprises a high-refractive-index layer with a relatively large refractive index and a low-refractive-index layer with a relatively small refractive index in the thickness direction. The anti-reflective layer attenuates the intensity of reflected light through interference between reflected light at multiple interfaces of the multiple thin layers (high-refractive-index layer and low-refractive-index layer). Furthermore, by adjusting the optical film thickness (the product of refractive index and thickness) of each thin layer in the anti-reflective layer, an interference effect that attenuates the intensity of reflected light can be achieved. Specifically, in this embodiment, the optical functional layer 20, serving as such an anti-reflective layer, sequentially comprises a first high-refractive-index layer 21, a first low-refractive-index layer 22, a second high-refractive-index layer 23, and a second low-refractive-index layer 24 on the side facing the thickness direction D.

[0045] The first high refractive index layer 21 and the second high refractive index layer 23 are each formed of a high refractive index material, preferably with a refractive index of 1.9 or higher at a wavelength of 550 nm. From the viewpoint of balancing high refractive index and low absorption of visible light, examples of high refractive index materials include niobium oxide (Nb₂O₅), titanium oxide, zirconium oxide, tin-doped indium oxide (ITO), and antimony-doped tin oxide (ATO), with niobium oxide being the preferred material.

[0046] The optical film thickness (the product of refractive index and thickness) of the first high refractive index layer 21 is, for example, 20 nm or more, and also, for example, 55 nm or less. The optical film thickness of the second high refractive index layer 23 is, for example, 60 nm or more, and also, for example, 330 nm or less.

[0047] The first low-refractive-index layer 22 and the second low-refractive-index layer 24 are each formed of a low-refractive-index material, preferably with a refractive index of 1.6 or less at a wavelength of 550 nm. From the viewpoint of balancing low refractive index and low absorption of visible light, examples of low-refractive-index materials include silicon dioxide (SiO2) and magnesium fluoride, with silicon dioxide being preferred. From the viewpoint of ensuring the tight adhesion between the second low-refractive-index layer 24 and the anti-fouling layer 30, silicon dioxide is also preferred as the material for the second low-refractive-index layer 24.

[0048] The optical thickness of the first low-refractive-index layer 22 is, for example, 15 nm or more, and also, for example, 70 nm or less. The optical thickness of the second low-refractive-index layer 24 is, for example, 100 nm or more, and also, for example, 160 nm or less.

[0049] Furthermore, in the optical functional layer 20, the thickness of the first high refractive index layer 21 is, for example, 1 nm or more, preferably 5 nm or more, and also, for example, 30 nm or less, preferably 20 nm or less. The thickness of the first low refractive index layer 22 is, for example, 10 nm or more, preferably 20 nm or more, and also, for example, 50 nm or less, preferably 30 nm or less. The thickness of the second high refractive index layer 23 is, for example, 50 nm or more, preferably 80 nm or more, and also, for example, 200 nm or less, preferably 150 nm or less. The thickness of the second low refractive index layer 24 is, for example, 60 nm or more, preferably 80 nm or more, and also, for example, 150 nm or less, preferably 100 nm or less.

[0050] The anti-fouling layer 30 is an anti-fouling layer in the optical film F, disposed on one side of the optical functional layer 20 in the thickness direction D. The anti-fouling layer 30 has an outer surface 31 on the side in the thickness direction D. The anti-fouling function of the anti-fouling layer 30 includes the function of inhibiting the adhesion of contaminants such as hand grease to the exposed surface of the film when using the optical film F, and the function of easily removing the adhered contaminants.

[0051] Examples of materials that can be used as the antifouling layer 30 include, for example, organic compounds containing fluorine groups. Among these, alkoxysilane compounds having perfluoropolyether groups are preferred. Examples of alkoxysilane compounds having perfluoropolyether groups include compounds represented by the following general formula (1).

[0052] R 1 -R 2 -X-(CH2) m-Si(OR 3 )3 (1)

[0053] In general formula (1), R 1 A straight-chain fluoroalkyl or branched fluoroalkyl (with, for example, 1 or more and 20 or less carbon atoms) is defined as an alkyl group in which one or more hydrogen atoms are replaced by fluorine atoms. More preferably, a perfluoroalkyl group is defined as an alkyl group in which all hydrogen atoms are replaced by fluorine atoms.

[0054] R 2 The structure represents a repeating structure containing at least one perfluoropolyether (PFPE) group, preferably a repeating structure containing two PFPE groups. Examples of repeating PFPE groups include repeating structures with linear PFPE groups and repeating structures with branched PFPE groups. Examples of repeating structures with linear PFPE groups include -(OC...) n F 2n ) p - The structure shown (n represents an integer greater than 1 and less than 20, p represents an integer greater than 1 and less than 50. The same applies below). As a repeating structure of a branched PFPE base, for example -(OC(CF3)2) p The structure shown is -(OCF2CF(CF3)CF2) p -The structure shown. As repeating structures of the PFPE group, linear repeating structures of the PFPE group are preferably listed, and -(OCF2) is more preferably listed. p - and -(OC2F4) p -

[0055] R 3 The alkyl group has 1 or more but less than 4 carbon atoms, and preferably methyl.

[0056] X represents an ether group, carbonyl group, amino group, or amide group, preferably an ether group.

[0057] m represents an integer greater than or equal to 1. Furthermore, m preferably represents an integer less than or equal to 20, more preferably less than or equal to 10, and even more preferably less than or equal to 5.

[0058] Among these alkoxysilane compounds having a perfluoropolyether group, compounds represented by the following general formula (2) are preferred.

[0059] CF3-(OCF2) q -(OC2F4) r -O-(CH2)3-Si(OCH3)3 (2)

[0060] In general formula (2), q represents an integer greater than 1 and less than 50, and r represents an integer greater than 1 and less than 50.

[0061] In addition, alkoxysilane compounds with perfluoropolyether groups can be used alone or in combination of two or more.

[0062] In this embodiment, the antifouling layer 30 is a film formed using a dry coating method (dry-coated film). Examples of dry coating methods include sputtering, vacuum evaporation, and CVD. The antifouling layer 30 is preferably a dry-coated film, and more preferably a vacuum-coated film.

[0063] The antifouling layer 30 is made of an alkoxysilane compound having a perfluoropolyether group, and its dry-coated film (preferably a vacuum-deposited film) configuration is suitable for ensuring high adhesion between the antifouling layer 30 and the optical functional layer 20, thus ensuring peel resistance of the antifouling layer 30. High peel resistance of the antifouling layer 30 helps maintain its antifouling performance.

[0064] The thickness of the antifouling layer 30 is preferably 1 nm or more, more preferably 2 nm or more, and even more preferably 3 nm or more. The thickness of the antifouling layer 30 is preferably 100 nm or less, more preferably 50 nm or less, and even more preferably 30 nm or less.

[0065] The water contact angle (pure water contact angle) of the outer surface 31 of the antifouling layer 30 is 110° or more, preferably 111° or more, more preferably 112° or more, further preferably 113° or more, and particularly preferably 114° or more. This high water contact angle of the outer surface 31 is suitable for achieving high antifouling properties in the antifouling layer 30. This water contact angle is, for example, 130° or less. The water contact angle is determined by forming a water droplet (pure water droplet) with a diameter of 2 mm or less on the outer surface 31 (exposed surface) of the antifouling layer 30 and measuring the contact angle of this water droplet relative to the surface of the antifouling layer 30. The water contact angle of the outer surface 31 can be adjusted, for example, by adjusting the composition of the antifouling layer 30, the roughness of the outer surface 31, the composition of the hard coating layer 12, and the surface roughness of the optical functional layer 20 side of the hard coating layer 12.

[0066] The surface roughness Ra (arithmetic mean surface roughness) of the outer surface 31 of the anti-fouling layer 30 is preferably 1 nm or more, more preferably 1.3 nm or more, and even more preferably 2 nm or more. This configuration is suitable for preventing the gloss of the outer surface 31 of the anti-fouling layer 30 from becoming too strong. The surface roughness Ra is preferably 20 nm or less, more preferably 18 nm or less, and even more preferably 17 nm or less. This configuration is preferred from the viewpoint of the optical properties and haze of the optical film F. For example, when the optical film F is provided on the surface of a display, it is suitable for suppressing white blurring of the image viewed through the optical film F.

[0067] The total reflectance (Y-value) of the anti-fouling layer 30 is preferably 1 or less, more preferably 0.9 or less. The specular reflectance (Y-value) of the anti-fouling layer 30 is preferably 0.9 or less, more preferably 0.8 or less. When the optical film F is provided on the surface of the display, these configurations are suitable for suppressing glare from the background on the surface of the display.

[0068] The difference ΔY(Y1-Y2) between the total reflectance Y value (Y1) and the specular reflectance Y value (Y2) is preferably greater than 0.13, more preferably greater than 0.15, and even more preferably greater than 0.17. This configuration is suitable for ensuring the anti-glare properties of the anti-fouling layer 30 or the optical film F. The difference ΔY is preferably less than 0.8, more preferably less than 0.7. When the optical film F is disposed on the surface of the display, this configuration is suitable for suppressing white blurring of the image observed through the optical film F.

[0069] The ratio (Y2 / Y1) of the specular reflection Y value (Y2) to the total reflection Y value (Y1) is preferably 0.15 or more, more preferably 0.18 or more. When the optical film F is disposed on the surface of the display, this configuration is suitable for suppressing white blurring of the image observed through the optical film F. This ratio (Y2 / Y1) is preferably 0.6 or less, more preferably 0.58 or less. This configuration is suitable for ensuring the anti-glare properties of the anti-fouling layer 30 or the optical film F.

[0070] The surface haze (external haze) of the antifouling layer 30 is preferably 20% or less, more preferably 10% or less. This configuration is suitable for ensuring the transparency of the optical film F. The surface haze of the antifouling layer 30 is, for example, 0.01% or more.

[0071] The optical thin film F can be fabricated by sequentially laminating an adhesive layer 40, an optical functional layer 20, and an antifouling layer 30 onto a transparent substrate 10, for example, using a roll-to-roll method, after preparing the transparent substrate 10. The optical functional layer 20 can be formed by sequentially laminating a first high refractive index layer 21, a first low refractive index layer 22, a second high refractive index layer 23, and a second low refractive index layer 24 onto the adhesive layer 40.

[0072] The transparent substrate 10 can be manufactured by forming a hard coating 12 on a resin film 11. The hard coating 12 can be formed, for example, by coating a curable resin composition containing a curable resin and, if desired, anti-glare microparticles onto the resin film 11 to form a coating film, followed by curing the coating film. When the curable resin composition contains an ultraviolet-curable resin, the coating film is cured by ultraviolet irradiation. When the curable resin composition contains a thermosetting resin, the coating film is cured by heating.

[0073] The exposed surface of the hard coating 12 formed on the transparent substrate 10 is subjected to surface modification treatment as needed. When performing plasma treatment as a surface modification treatment, argon gas, for example, is used as an inactive gas. In addition, the discharge power in the plasma treatment is, for example, 10W or more, and, for example, 10000W or less.

[0074] The bonding layer 40, the first high refractive index layer 21, the first low refractive index layer 22, the second high refractive index layer 23, and the second low refractive index layer 24 can be formed by applying a film to the material using a dry coating method. Examples of dry coating methods include sputtering, vacuum evaporation, and CVD, with sputtering being the preferred method.

[0075] In sputtering, gas is introduced into the sputtering chamber under vacuum conditions, and a negative voltage is applied to a target positioned on the cathode. This causes a glow discharge, ionizing the gas atoms. These gas ions then bombard the target surface at high speed, ejecting target material, which then deposits on a predetermined surface. From the viewpoint of film deposition rate, reactive sputtering is preferred for forming a metal oxide layer. In reactive sputtering, a metal target is used, and a mixture of an inert gas (such as argon) and oxygen (the reactive gas) is used. By adjusting the flow rate ratio (sccm) of the inert gas to oxygen, the proportion of oxygen in the formed metal oxide layer can be adjusted.

[0076] Examples of power sources used for sputtering include DC power supplies, AC power supplies, RF power supplies, and MFAC power supplies (AC power supplies with a frequency band of tens to hundreds of MHz). The discharge voltage in sputtering is, for example, 200V or higher, and also, for example, 1000V or lower. Furthermore, the film-forming gas pressure in the sputtering chamber where sputtering is performed is, for example, 0.01Pa or higher, and also, for example, 2Pa or lower.

[0077] The antifouling layer 30 can be formed by depositing, for example, an organic compound containing a fluorine group on the optical functional layer 20. Examples of methods for forming the antifouling layer 30 include dry coating. Examples of dry coating methods include vacuum evaporation, sputtering, and CVD; vacuum evaporation is preferred.

[0078] For example, by operating as described above, an optical film F can be manufactured. The optical film F is used by attaching the transparent substrate 10 side to the substrate using, for example, an adhesive.

[0079] The optical thin film F can be any optical thin film other than an anti-reflective film. Examples of other optical thin films include transparent conductive films and electromagnetic wave shielding films.

[0080] When the optical thin film F is a transparent conductive thin film, the optical functional layer 20 of the optical thin film F, for example, sequentially comprises a first dielectric film, an ITO film, or other transparent electrode film, and a second dielectric film on the side facing the thickness direction D. The optical functional layer 20 with this layered structure can balance visible light transmittance and conductivity.

[0081] When the optical thin film F is an electromagnetic wave shielding film, the optical functional layer 20 of the optical thin film F may, for example, alternately possess a metal thin film and a metal oxide film with electromagnetic wave reflectivity in the thickness direction D. The optical functional layer 20 with this stacked structure can achieve both shielding against electromagnetic waves of a specific wavelength and visible light transmittance.

[0082] like Figure 2 As shown, the optical film F may have an adhesive layer 50 disposed on the other side of the transparent substrate 10 in the thickness direction D.

[0083] The adhesive layer 50 is a layer formed by the adhesive composition and is transparent. The adhesive composition contains at least a base polymer that enables the adhesive layer 50 to exhibit adhesiveness. Examples of base polymers include acrylic polymers, rubber-based polymers, silicone-based polymers, urethane-based polymers, polyester-based polymers, and polyamide-based polymers. From the viewpoint of simultaneously achieving the required adhesive strength and high transparency for the adhesive layer 50 of the optical film F, an acrylic polymer is preferably used as the base polymer.

[0084] From the viewpoint of achieving sufficient adhesion between the optical thin film F and the substrate, the thickness of the adhesive layer 50 is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more. Furthermore, from the viewpoint of ensuring transparency, the thickness of the adhesive layer 50 is preferably 300 μm or less, more preferably 200 μm or less, and even more preferably 100 μm or less.

[0085] Figure 2 The optical thin film F shown can be manufactured, for example, as follows: First, an adhesive composition is coated onto a release liner to form a coating film. Next, the coating film on the release liner is dried as needed. This forms an adhesive layer 50 on the release liner. Then, the exposed surface of the adhesive layer 50 is... Figure 1 The other side of the transparent substrate 10 of the optical thin film F shown (in the thickness direction D) Figure 1 (The lower surface is attached). For example, this operation can produce... Figure 2 The optical thin film F shown.

[0086] When the optical film F has an adhesive layer 50, no additional adhesive is needed when bonding the objects to be bonded.

[0087] Example

[0088] The following embodiments are provided for detailed description of the present invention. The present invention is not limited to these embodiments. Furthermore, the specific values ​​of the blending amount (content), physical property values, parameters, etc., described below can be replaced with the corresponding upper limit (defined as a value in the form of "below" or "less than") or lower limit (defined as a value in the form of "above" or "more than") of the blending amount (content), physical property values, parameters, etc., described in the above "Specific Embodiments".

[0089] [Example 1]

[0090] First, an anti-glare hard coating is formed on one side of a cellulose triacetate (TAC) film (80 μm thick), which is a transparent resin film (hard coating formation process). In this process, firstly, 50 parts by weight of UV-curable urethane acrylate (trade name "UV1700TL", manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), 50 parts by weight of UV-curable multifunctional acrylate (trade name "Viscoat#300", main component is pentaerythritol triacrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.), 3 parts by weight of polymethyl methacrylate particles (trade name "TECHPOLYMER", average particle size 3μm, refractive index 1.525, manufactured by Sekisui Chemicals Co., Ltd.) as anti-glare microparticles, 1.5 parts by weight of silicone particles (trade name "TOSPEARL 130", average particle size 3μm, refractive index 1.42, manufactured by Momentive Performance Materials Japan) as anti-glare microparticles, 1.5 parts by weight of thixotropic agent (trade name "Lucentite SAN", synthetic montmorillonite as organoclay, manufactured by Co-op Chemical Co., Ltd.), and photopolymerization initiator (trade name "OMNIRAD"). A composition (varnish) with a solid content of 55% by weight was prepared by mixing 3 parts by weight of 907 (manufactured by BASF), 0.15 parts by weight of leveling agent (trade name "LE303", manufactured by Kyoei Chemical Co., Ltd.), and a mixed solvent of toluene / ethyl acetate / cyclopentanone (mass ratio of 35:41:24). An ultrasonic disperser was used for mixing. The composition was then coated onto one side of the above-mentioned TAC film to form a coating. The coating was then cured by ultraviolet irradiation and dried by heating. For ultraviolet irradiation, a high-pressure mercury lamp was used as the light source, and ultraviolet light with a wavelength of 365 nm was used, with a cumulative irradiation dose set to 300 mJ / cm². 2 Additionally, the heating temperature was set to 80°C and the heating time to 60 seconds. This resulted in the formation of an 8 μm thick anti-glare hard coating (first HC layer) on the TAC film.

[0091] Next, the surface of the HC layer of the TAC thin film with the HC layer is subjected to plasma treatment in a vacuum atmosphere of 1.0 Pa using a roller-to-roll plasma treatment apparatus. In this plasma treatment, argon is used as the inactive gas, and the discharge power is set to 2400 W.

[0092] Next, an adhesion layer and an anti-reflection layer are sequentially formed on the HC layer of the plasma-treated TAC thin film with the HC layer (sputtering film deposition process). Specifically, using a roll-to-roll sputtering film deposition apparatus, a 3.5 nm thick SiOx layer (x<2) as an adhesion layer, a 12 nm thick Nb2O5 layer as a first high refractive index layer, a 28 nm thick SiO2 layer as a first low refractive index layer, a 100 nm thick Nb2O5 layer as a second high refractive index layer, and an 85 nm thick SiO2 layer as a second low refractive index layer are sequentially formed on the HC layer of the plasma-treated TAC thin film with the HC layer. In the formation of the adhesion layer, a Si target is used, and argon gas as an inactive gas and oxygen gas as a reactive gas in a ratio of 3 parts by volume to 100 parts by volume of argon gas are used. The discharge voltage is set to 520 V, and the gas pressure in the film deposition chamber (film deposition pressure) is set to 0.27 Pa. The SiOx layer (x<2) is formed by MFAC sputtering. In the formation of the first high-refractive-index layer, an Nb target was used, along with 100 parts by volume of argon and 5 parts by volume of oxygen. The discharge voltage was set to 415 V, and the film-forming pressure was set to 0.42 Pa. The Nb₂O₅ layer was formed by MFAC sputtering. In the formation of the first low-refractive-index layer, a Si target was used, along with 100 parts by volume of argon and 30 parts by volume of oxygen. The discharge voltage was set to 350 V, and the film-forming pressure was set to 0.3 Pa. The SiO₂ layer was formed by MFAC sputtering. In the formation of the second high-refractive-index layer, an Nb target was used, along with 100 parts by volume of argon and 13 parts by volume of oxygen. The discharge voltage was set to 460 V, and the film-forming pressure was set to 0.5 Pa. The Nb₂O₅ layer was formed by MFAC sputtering. In the formation of the second low-refractive-index layer, a Si target is used, along with 100 parts by volume of argon and 30 parts by volume of oxygen. The discharge voltage is set to 340V, and the film-forming pressure is set to 0.25Pa. The SiO2 layer is formed by MFAC sputtering. Following the above operation, an anti-reflective layer (first high-refractive-index layer, first low-refractive-index layer, second high-refractive-index layer, and second low-refractive-index layer) is formed by stacking on the HC layer of the TAC thin film with the HC layer, with an adhesive layer in between.

[0093] Next, an antifouling layer is formed on the formed antireflective layer (antifouling layer formation process). Specifically, an antifouling layer with a thickness of 7 nm is formed on the antireflective layer by using a vacuum evaporation method with an alkoxysilane compound containing a perfluoropolyether group as the evaporation source. The evaporation source is a solid component obtained by drying "Optool UD509" (an alkoxysilane compound containing a perfluoropolyether group as shown in the above general formula (2), with a solid component concentration of 20% by mass) manufactured by Daikin Industries, Ltd. In addition, the heating temperature of the evaporation source in the vacuum evaporation method is set to 260°C.

[0094] The optical film of Example 1 is fabricated as described above. The optical film of Example 1 comprises, sequentially, a transparent substrate (resin film, hard coating), an adhesive layer, an anti-reflective layer, and an anti-fouling layer on the side facing the thickness direction.

[0095] [Example 2]

[0096] As the vapor deposition source in the antifouling layer formation process, the solid component obtained by drying "Optool UD120" (an alkoxysilane compound containing a perfluoropolyether group) manufactured by Daikin Industries, Ltd. was used. Otherwise, the optical film of Example 2 was produced by operating in the same manner as the optical film of Example 1.

[0097] [Example 3]

[0098] First, an anti-glare hard coating is formed on one side of a cellulose triacetate (TAC) film (80 μm thick), which is a transparent resin film (hard coating formation process). In this process, 100 parts by weight of UV-curable acrylic monomer (trade name "GRANDIC PC-1070", manufactured by DIC Corporation), 25 parts by weight of organosilicon sol (trade name "MEK-ST-L", with an average primary particle size of 50 nm and a solids concentration of 30% by weight, manufactured by Nissan Chemical Co., Ltd.) containing nano-silica particles as anti-glare microparticles, converted from nano-silica particles, 1.5 parts by weight of thixotropic agent (trade name "Lucentite SAN", synthetic montmorillonite as organoclay, manufactured by Co-op Chemical Co., Ltd.), 3 parts by weight of photopolymerization initiator (trade name "OMNIRAD907", manufactured by BASF Corporation), and 0.15 parts by weight of leveling agent (trade name "LE303", manufactured by Kyoeisha Chemical Co., Ltd.) are mixed to prepare a composition (varnish) with a solids concentration of 55% by weight. An ultrasonic disperser is used for mixing. Next, the composition is coated onto one side of the aforementioned TAC film to form a coating. The coating is then cured by ultraviolet irradiation and dried by heating. In the ultraviolet irradiation, a high-pressure mercury lamp is used as the light source, and ultraviolet light with a wavelength of 365 nm is used, with the cumulative irradiation dose set to 200 mJ / cm². 2Additionally, the heating temperature was set to 80°C and the heating time to 3 minutes. This resulted in the formation of a 6 μm thick anti-glare hard coating (second HC layer) on the TAC film.

[0099] Next, the surface of the HC layer of the TAC thin film with the HC layer was subjected to plasma treatment using a roller-to-roll plasma treatment apparatus under a vacuum atmosphere of 1.0 Pa. In this plasma treatment, argon was used as the inactive gas, and the discharge power was set to 150 W.

[0100] Next, an adhesion layer and an anti-reflection layer are sequentially formed on the HC layer of the plasma-treated TAC thin film with the HC layer (sputtering deposition process). Specifically, using a roll-to-roll sputtering deposition apparatus, an indium tin oxide (ITO) layer with a thickness of 1.5 nm as an adhesion layer, a Nb₂O₅ layer with a thickness of 12 nm as a first high refractive index layer, a SiO₂ layer with a thickness of 28 nm as a first low refractive index layer, a Nb₂O₅ layer with a thickness of 100 nm as a second high refractive index layer, and a SiO₂ layer with a thickness of 85 nm as a second low refractive index layer are sequentially formed on the HC layer of the plasma-treated TAC thin film with the HC layer. In the formation of the adhesion layer, an ITO target is used, and argon gas as an inactive gas and oxygen gas as a reactive gas in a ratio of 10 parts by volume to 100 parts by volume of argon gas are used. The discharge voltage is set to 400 V, and the gas pressure in the deposition chamber (deposition pressure) is set to 0.2 Pa. The ITO layer is formed by MFAC sputtering. The formation conditions of the first high refractive index layer, the first low refractive index layer, the second high refractive index layer, and the second low refractive index layer in this embodiment are the same as those of the first high refractive index layer, the first low refractive index layer, the second high refractive index layer, and the second low refractive index layer in Example 1.

[0101] Next, an antifouling layer is formed on the formed antireflective layer (antifouling layer formation process). Specifically, it is the same as the antifouling layer formation process in Example 1 (using the solid component obtained by drying "Optool UD509" manufactured by Daikin Industries, Ltd. as the vapor deposition source).

[0102] The optical film of Example 3 was fabricated as described above. The optical film of Example 3 comprises, sequentially along its thickness direction, a transparent substrate (resin film, hard coating), an adhesive layer, an anti-reflective layer, and an anti-fouling layer.

[0103] [Example 4]

[0104] As the vapor deposition source in the antifouling layer formation process, the solid component obtained by drying "Optool UD120" (an alkoxysilane compound containing a perfluoropolyether group) manufactured by Daikin Industries, Ltd. was used. Otherwise, the optical film of Example 4 was produced by operating in the same manner as the optical film of Example 3.

[0105] [Example 5]

[0106] As the vapor deposition source in the antifouling layer formation process, the solid component obtained by drying "KY-1901" (an alkoxysilane compound containing a perfluoropolyether group) manufactured by Shin-Etsu Chemical Industry Co., Ltd. was used. Otherwise, the optical film of Example 5 was produced by operating in the same manner as the optical film of Example 3.

[0107] [Example 6]

[0108] Except for the hard coating formation process and the antifouling layer formation process, the optical film of Example 6 is produced by operating in the same manner as the optical film of Example 3.

[0109] In the hard coating formation process of Example 6, firstly, 67 parts by mass of an acrylic monomer composition containing nano-silica particles (trade name "NC035", average primary particle size of nano-silica particles is 40 nm, solid content concentration is 50% by mass, proportion of nano-silica particles in solid content is 60% by mass, manufactured by Arakawa Chemical Industry Co., Ltd.), 33 parts by mass of a UV-curable multifunctional acrylate (trade name "Adhesive A", solid content concentration is 100% by mass, manufactured by Arakawa Chemical Industry Co., Ltd.), 3 parts by mass of polymethyl methacrylate particles (trade name "TECHPOLYMER", average particle size is 3 μm, refractive index is 1.525, manufactured by Sekisui Chemicals Co., Ltd.), and 3 parts by mass of silicone particles (trade name "TOSPEARL 130", average particle size is 3 μm, refractive index is 1.42, manufactured by Momentive Performance Materials Co., Ltd.), which are used as anti-glare microparticles. A composition (varnish) with a solid content of 45% by weight was prepared by mixing 1.5 parts by weight of a thixotropic agent (trade name "Lucentit SAN", synthetic montmorillonite as an organoclay, manufactured by Co-op Chemical Co., Ltd.), 3 parts by weight of a photopolymerization initiator (trade name "OMNIRAD907", manufactured by BASF Co., Ltd.), 0.15 parts by weight of a leveling agent (trade name "LE303", manufactured by Kyoei Chemical Co., Ltd.), and toluene. An ultrasonic disperser was used for mixing. The composition was then coated onto one side of the above-mentioned TAC film to form a coating. The coating was then cured by ultraviolet irradiation and dried by heating. For ultraviolet irradiation, a high-pressure mercury lamp was used as the light source, and ultraviolet light with a wavelength of 365 nm was used, with a cumulative irradiation dose set to 200 mJ / cm². 2 Additionally, the heating temperature was set to 60°C and the heating time to 60 seconds. This resulted in the formation of a 7 μm thick anti-glare hard coating (third HC layer) on the TAC film.

[0110] In the antifouling layer formation process of Example 6, the solid component obtained by drying "Optool UD120" (an alkoxysilane compound containing a perfluoropolyether group) manufactured by Daikin Industries, Ltd. was used as the vapor deposition source.

[0111] [Example 7]

[0112] As the vapor deposition source in the antifouling layer formation process, the solid component obtained by drying "KY-1901" (an alkoxysilane compound containing a perfluoropolyether group) manufactured by Shin-Etsu Chemical Industry Co., Ltd. was used. Otherwise, the optical film of Example 7 was produced by operating in the same manner as the optical film of Example 6.

[0113] [Example 8]

[0114] Except for the hard coating formation process and the antifouling layer formation process, the optical film of Example 8 is produced by operating in the same manner as the optical film of Example 3.

[0115] In the hard coating formation process of Example 8, firstly, 83 parts by mass of an acrylic monomer composition containing nano-silica particles (trade name "NC035HS", average primary particle size of nano-silica particles of 40 nm, solid content concentration of 50% by mass, proportion of nano-silica particles in solid content of 60% by mass, manufactured by Arakawa Chemical Industry Co., Ltd.), 17 parts by mass of UV-curable polyfunctional urethane acrylate (trade name "BEAMSET 580", solid content concentration of 70% by mass, manufactured by Arakawa Chemical Industry Co., Ltd.), 4 parts by mass of polymethyl methacrylate particles as anti-glare microparticles (trade name "TECHPOLYMER", average particle size of 3 μm, refractive index of 1.495, manufactured by Sekisui Chemicals Co., Ltd.), and 4 parts by mass of silicone particles as anti-glare microparticles (trade name "TOSPEARL 130", average particle size of 3 μm, refractive index of 1.42, manufactured by Momentive Performance Materials Co., Ltd.). A composition (varnish) with a solid content of 42% by weight was prepared by mixing 0.1 parts by weight of a thixotropic agent (trade name "Lucentit SAN", synthetic montmorillonite as an organoclay, manufactured by Co-op Chemical Co., Ltd.), 3 parts by weight of a photopolymerization initiator (trade name "OMNIRAD907", manufactured by BASF Co., Ltd.), 0.15 parts by weight of a leveling agent (trade name "LE303", manufactured by Kyoei Chemical Co., Ltd.), and butyl acetate. An ultrasonic disperser was used for mixing. The composition was then coated onto one side of the above-mentioned TAC film to form a coating. The coating was then cured by ultraviolet irradiation and dried by heating. For ultraviolet irradiation, a high-pressure mercury lamp was used as the light source, and ultraviolet light with a wavelength of 365 nm was used, with a cumulative irradiation dose set to 200 mJ / cm². 2 Additionally, the heating temperature was set to 60°C and the heating time to 60 seconds. This resulted in the formation of an 8 μm thick anti-glare hard coating (fourth HC layer) on the TAC film.

[0116] In the antifouling layer formation process of Example 8, the solid component obtained by drying "KY-1903-1" (an alkoxysilane compound containing a perfluoropolyether group) manufactured by Shin-Etsu Chemical Industry Co., Ltd. was used as the vapor deposition source.

[0117] [Comparative Example 1]

[0118] Except for the antifouling layer formation process, the optical film of Comparative Example 1 was produced by operating in the same manner as the optical film of Example 1.

[0119] In the antifouling layer formation process of Comparative Example 1, "Optool UD509" (manufactured by Daikin Industries, Ltd.), used as a coating agent, was first diluted with a diluent (trade name "Fluorinert," manufactured by 3M Corporation) to prepare a coating solution with a solid content concentration of 0.1% by mass. Next, the coating solution was applied to the antireflective layer formed by the sputtering process using gravure coating to form a coating film. The coating film was then dried by heating at 60°C for 2 minutes. Thus, an antifouling layer with a thickness of 7 nm was formed on the antireflective layer.

[0120] <Water contact angle>

[0121] For each optical film of Examples 1-8 and Comparative Example 1, the water contact angle of the antifouling layer surface was investigated. First, a water droplet was formed by dropping approximately 1 μL of pure water onto the antifouling layer surface of the optical film. Next, the angle between the surface of the water droplet and the surface of the antifouling layer was measured. A contact angle meter (trade name "DMo-501", manufactured by Kyowa Interface Science Co., Ltd.) was used for the measurement. The measurement results are shown in Table 1.

[0122] <Surface Roughness Ra>

[0123] For each optical thin film of Examples 1-8 and Comparative Example 1, the surface roughness Ra of the antifouling layer was investigated. Specifically, the surface of the antifouling layer of each optical thin film was observed using an atomic force microscope (trade name "SPI3800", manufactured by Seiko Instruments Inc.), and the surface roughness Ra (arithmetic mean roughness) was calculated in a 1 μm square observation image. The results are shown in Table 1.

[0124] Total reflection and specular reflection

[0125] For each optical thin film of Examples 1 to 8 and Comparative Example 1, the total reflectance Y value and specular reflectance Y value were measured as follows.

[0126] First, the transparent substrate side of a sample film (50mm × 50mm) cut from an optical film is bonded to a black acrylic sheet using an adhesive. Next, total reflectance is measured on the sample bonded to the black acrylic sheet using a spectrophotometer (trade name "U-4100", manufactured by Hitachi Advanced Technology Co., Ltd.). Based on the spectral reflectance at wavelengths of 380–780 nm obtained through this measurement and the relative spectral distribution of the CIE standard irradiator D65, the trichromatic stimulus values ​​Y of the object color based on reflection in the XYZ color system specified in JIS Z8701 are calculated, and the total reflectance Y value is determined.

[0127] In addition, for the aforementioned sample adhered to a black acrylic sheet, specular reflectance was measured using a spectrophotometer (trade name "U-4100") with scattered light removed using the tools included with the U-4100, at a light incident angle of 5°. Based on the spectrophotometric reflectance at wavelengths of 380–780 nm obtained through this measurement and the relative spectrophotometric distribution of the CIE standard irradiator D65, the trichromatic stimulus value Y of the object color based on reflection in the XYZ color system specified in JIS Z8701 was calculated, and the specular reflectance Y value was determined.

[0128] The total reflection Y value (Y1), the specular reflection Y value (Y2), the difference between the total reflection Y value and the specular reflection Y value ΔY(Y1-Y2), and the ratio of the specular reflection Y value to the total reflection Y value (Y2 / Y1) are shown in Table 1.

[0129] <Surface Haze>

[0130] The surface haze of each optical film of Examples 1-8 and Comparative Example 1 was investigated. Specifically, firstly, for the sample film cut from the optical film, haze measurement was performed using a "HM150 haze meter" manufactured by Murakami Color Technology Research Institute according to JIS K 7136 (2000) (thus measuring the total haze value of the sample film). Next, a cyclic olefin polymer film was bonded to the antifouling layer side surface of the sample film using an adhesive. With the surface haze of the sample film eliminated, haze measurement was performed using a "HM150 haze meter" manufactured by Murakami Color Technology Research Institute according to JIS K 7136 (2000) (thus measuring the internal haze value of the sample film). Furthermore, the external haze (surface haze) value was obtained by subtracting the internal haze value from the total haze value. The values ​​are shown in Table 1.

[0131] <Evaluation of stain resistance>

[0132] The antifouling properties of the antifouling layers of each optical film of Examples 1-8 and Comparative Example 1 were investigated. Specifically, a fingerprint was first left on the surface of the antifouling layer of the optical film by touching it with a finger. Then, a cotton swab was used to wipe the fingerprint three times (the cotton swab was brought into contact with the area of ​​the antifouling layer surface, including the fingerprint, and the cotton swab was scanned in one direction). The antifouling properties of the antifouling layer were evaluated as "good" if the fingerprint could be wiped off after three wiping operations, and "poor" if the fingerprint could not be wiped off after three wiping operations (i.e., some fingerprint remained). The results are shown in Table 1.

[0133] [Table 1]

[0134]

[0135] The above embodiments are illustrative of the present invention, and the present invention is not limited to these embodiments. Variations of the present invention that will be apparent to those skilled in the art are included in the foregoing claims.

[0136] Industrial availability

[0137] The optical film with anti-fouling layer of the present invention can be applied to, for example, anti-reflective films with anti-fouling layers, transparent conductive films with anti-fouling layers, and electromagnetic wave shielding films with anti-fouling layers.

[0138] Explanation of reference numerals in the attached figures

[0139] F Optical film (optical film with anti-fouling layer)

[0140] 10 Transparent substrate

[0141] 11 Resin film

[0142] 12 Hard coating

[0143] 20 Optical Functional Layers

[0144] 21 First High Refractive Index Layer

[0145] 22 First low-refractive-index layer

[0146] 23 Second High Refractive Index Layer

[0147] 24 Second low-refractive-index layer

[0148] 30 anti-fouling layer

[0149] 31 Outer surface

[0150] 40 sealing layers

[0151] 50 Adhesive layers

Claims

1. An optical film with an anti-fouling layer, comprising, in sequence, a transparent substrate, an optical functional layer, and an anti-fouling layer. The outer surface of the antifouling layer, opposite to the optical functional layer, has a water contact angle of more than 114°, and the surface roughness Ra of the outer surface is less than 20 nm. The antifouling layer is a film of an alkoxysilane compound having a perfluoropolyether group, as shown in the following general formula (1). R 1 -R 2 -X-(CH2) m -Si(OR 3 )3 (1) In general formula (1), R 1 R indicates perfluoroalkyl. 2 This indicates the inclusion of -(OCF2). p - and - (OC2F4) p - a perfluoropolyether-based repeating structure, where p represents an integer greater than 1 and less than 50, R 3 This indicates an alkyl group with 1 or more but less than 4 carbon atoms; X represents an ether, carbonyl, amino, or amide group; and m represents an integer of 1 or more. The total reflectance Y value of the antifouling layer is below 0.

55.

2. The optical thin film with an anti-fouling layer according to claim 1, wherein, The outer surface has a surface roughness Ra of more than 2 nm.

3. The optical thin film with an anti-fouling layer according to claim 1 or 2, wherein, The optical functional layer is an anti-reflective layer.

4. The optical thin film with an anti-fouling layer according to claim 3, wherein, The antireflective layer alternately comprises a high refractive index layer with a relatively large refractive index and a low refractive index layer with a relatively small refractive index.

5. The optical thin film with an anti-fouling layer according to claim 1, wherein, The transparent substrate has a hard coating on the optical functional layer side.

6. The optical thin film with an anti-fouling layer according to claim 5, wherein, The hard coating contains metal oxide particles.

7. The optical thin film with an anti-fouling layer according to claim 6, wherein, The metal oxide particles are nano-silica particles.

8. The optical thin film with an anti-fouling layer according to any one of claims 5 to 7, wherein, The surface of the optical functional layer side of the hard coating has a surface roughness Ra of more than 0.5 nm and less than 20 nm.

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