Anti-reflection film with transparent substrate

Abstract

The present invention pertains to a transparent substrate with an anti-reflective film, that comprises a multilayer film on at least one out of two main surfaces of the transparent substrate. The multilayer film comprises at least two laminated layers that have different refractive indexes. One silicon oxide layer among the layers of the multilayer film has a moisture permeability of no more than 300 g / m2 / day.

Description

[Technical Field]

[0001] The present invention relates to a transparent substrate with an antireflection film. [Background technology]

[0002] In recent years, from the viewpoint of aesthetic appearance, a method of placing a cover glass on the front surface of an image display device such as a liquid crystal display has been used.

[0003] One of the problems with the above technology is glare caused by the cover glass reflecting external light. To solve this problem, a multilayer film with a laminated structure is often applied to the surface of the cover glass. However, with conventional anti-reflection films, the boundary between the black frame and the image display area of ​​the image display device becomes conspicuous, resulting in poor aesthetics.

[0004] To address this issue, it is known to impart light absorption properties to anti-reflection coatings, which are multilayer films made by laminating at least two dielectric layers with different refractive indices. This makes it possible to make the boundary between the black frame and the image display area of ​​the image display device less noticeable. It also reduces reflections from the interface between the cover glass and the anti-reflection coating.

[0005] For example, Patent Document 1 discloses a transparent substrate with an antireflection film that has light absorption ability and is insulating.

[0006] Patent Document 2 discloses a transparent conductive laminate in which a silicon oxide layer and a copper layer are laminated in this order.

[0007] Patent Document 3 discloses an anti-reflection coating having a coating made of a high refractive index material and a coating made of a low refractive index material on the surface of a glass plate, with the coating made of the low refractive index material disposed on the outermost surface. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 2018-115105 [Patent Document 2] Japanese Patent Application Publication No. 2016-068470 [Patent Document 3] Japanese Patent Application Publication No. 2008-201633 Summary of the Invention [Problem to be solved by the invention]

[0009] As described above, there is known a technique for imparting light absorption capability to a multilayer film to provide aesthetic appeal and further suppressing reflection from the interface between the cover glass and the anti-reflection film.

[0010] However, an anti-reflection film that has both light absorption ability and the ability to suppress changes in transmittance due to the intrusion of moisture from the outside has not yet been realized.

[0011] Therefore, an object of the present invention is to provide a transparent substrate with an antireflection film that has light absorption ability and is capable of suppressing changes in transmittance of the antireflection film due to the intrusion of moisture from the outside. [Means for solving the problem]

[0012] The present inventors have provided a multilayer film having at least two layers with different refractive indices laminated on at least one of the main surfaces of a transparent substrate having two main surfaces, at least one of the layers of the multilayer film being a silicon oxide layer with a moisture permeability of 300 g / m 2 / day or less, the present inventors have found that the above problems can be solved by using a transparent substrate with an anti-reflection film, and have completed the present invention.

[0013] In one embodiment of the transparent substrate with an anti-reflection film of the present invention, the multilayer film has a structure in which at least two layers having different refractive indices are stacked together, and at least one of the layers of the multilayer film is composed mainly of an oxide of Si, and at least another layer of the multilayer film is composed mainly of a mixed oxide of at least one oxide selected from Group A consisting of Mo and W and at least one oxide selected from Group B consisting of Si, Nb, Ti, Zr, Ta, Al, Sn, and In, and it is preferable that the content of the elements of Group B contained in the mixed oxide is less than 80 mass% relative to the total of the elements of Group A contained in the mixed oxide and the elements of Group B contained in the mixed oxide.

[0014] In the antireflection-coated transparent substrate of one embodiment of the present invention, at least one silicon oxide layer among the layers of the multilayer film preferably has an arithmetic mean height (Sa), which represents surface roughness in a measurement area of ​​1 μm×1 μm, of 1.00 nm or less.

[0015] In the antireflection-coated transparent substrate of one embodiment of the present invention, at least one silicon oxide layer among the layers of the multilayer film preferably has an arithmetic mean height (Sa), which represents surface roughness in a measurement area of ​​5 μm×5 μm, of 0.90 nm or less.

[0016] In the antireflection-coated transparent substrate according to one aspect of the present invention, at least one silicon oxide layer of the multilayer film preferably has a hardness of 5.0 GPa or more.

[0017] In the antireflection-coated transparent substrate according to one aspect of the present invention, at least one silicon oxide layer of the multilayer film preferably has an elastic modulus of 70 GPa or more.

[0018] In the antireflection-coated transparent substrate according to one embodiment of the present invention, it is preferable that an antifouling film be further provided on the antireflection film.

[0019] In the antireflection-coated transparent substrate according to one aspect of the present invention, the transparent substrate is preferably a glass substrate.

[0020] In the antireflection-coated transparent substrate according to one aspect of the present invention, the transparent substrate is preferably a resin substrate.

[0021] In the transparent substrate with an antireflection film according to one aspect of the present invention, the transparent substrate is preferably a laminate composed of a glass substrate and a resin substrate.

[0022] In the antireflection-coated transparent substrate according to one aspect of the present invention, the glass is preferably chemically strengthened.

[0023] In the transparent substrate with an antireflection film according to one aspect of the present invention, the transparent substrate preferably has an antiglare treatment applied to a main surface on the side having the antireflection film.

[0024] In the transparent substrate with an antireflection film according to one aspect of the present invention, an image display device is preferably provided with the transparent substrate with an antireflection film. [Effects of the Invention]

[0025] According to one aspect of the present invention, it is possible to provide a transparent substrate with an antireflection film that has light absorption ability and in which a change in transmittance of the antireflection film due to the intrusion of moisture from the outside is suppressed. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 is a cross-sectional view schematically showing one example of the configuration of a transparent substrate with an antireflection film. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0028] The transparent substrate with an anti-reflection film according to one embodiment of the present invention is provided with a multilayer film in which at least two layers having different refractive indices are laminated on at least one of the two main surfaces of a transparent substrate, and at least one silicon oxide layer in the multilayer film has a moisture permeability of 300 g / m2 / day or less.

[0029] The transparent substrate according to this embodiment is not particularly limited as long as it is a transparent substrate with excellent light transmittance, and examples thereof include glass and resin.

[0030] The multilayer film in the antireflection film-coated transparent substrate (multilayer film-coated transparent substrate) according to this embodiment preferably has the following configuration.

[0031] Fig. 1 is a cross-sectional view schematically showing one example of the configuration of a transparent substrate with a multilayer film. A multilayer film 30 is formed on a transparent substrate 10. The multilayer film 30 shown in Fig. 1 has a laminated structure in which two dielectric layers 32 and 34 with different refractive indices are laminated. By laminating the dielectric layers 32 and 34 with different refractive indices, light reflection is suppressed. The dielectric layer 32 is a high refractive index layer, and the dielectric layer 34 is a low refractive index layer.

[0032] 1, the dielectric layer 32 is preferably made of a mixed oxide of at least one element selected from Group A consisting of Mo and W and at least one element selected from Group B consisting of Si, Nb, Ti, Zr, Ta, Al, Sn, and In. However, the mixed oxide preferably has a content of Group B elements contained in the mixed oxide (hereinafter referred to as Group B content) of less than 80 mass% relative to the total of the Group A elements contained in the mixed oxide and the Group B elements contained in the mixed oxide.

[0033] The dielectric layer 34 is made of SiO x It is preferable that the ion exchange membrane is made up of:

[0034] The dielectric layer 32 is preferably made of a mixed oxide of at least one oxide selected from Group A consisting of Mo and W, and at least one oxide selected from Group B consisting of Si, Nb, Ti, Zr, Ta, Al, Sn, and In. Among these, Mo is preferred as Group A, and Nb is preferred as Group B.

[0035] By using Mo and Nb in dielectric layer 34, which is an oxygen-deficient silicon oxide layer, and dielectric layer 32, it is more preferable that the silicon oxide layer does not take on a yellowish color when exposed to visible light, even if it is oxygen-deficient, because Mo and Nb are used.

[0036] The refractive index of the dielectric layer 32 at a wavelength of 550 nm is preferably 1.8 to 2.3 from the viewpoint of transmittance through the transparent substrate. The extinction coefficient of the dielectric layer 32 is preferably 0.005 to 3, more preferably 0.01 to 1, and even more preferably 0.04 to 0.38.

[0037] If the extinction coefficient is 0.005 or more, the desired absorptance can be achieved with an appropriate number of layers. If the extinction coefficient is 3 or less, it is relatively easy to achieve both reflection color and transmittance.

[0038] 1 has a laminated structure in which two dielectric layers 32 and 34 are stacked, but the multilayer film in this embodiment is not limited to this and may have a laminated structure in which three or more layers with different refractive indices are stacked. In this case, it is not necessary for all layers to have different refractive indices.

[0039] For example, a three-layer laminate structure may be a three-layer laminate structure of a low refractive index layer, a high refractive index layer, and a low refractive index layer, or a three-layer laminate structure of a high refractive index layer, a low refractive index layer, and a high refractive index layer. In the former case, the two low refractive index layers may have the same refractive index, and in the latter case, the two high refractive index layers may have the same refractive index.

[0040] In the case of a four-layer laminated structure, it can be a four-layer laminated structure of a low refractive index layer, a high refractive index layer, a low refractive index layer, and a high refractive index layer, or a four-layer laminated structure of a high refractive index layer, a low refractive index layer, a high refractive index layer, and a low refractive index layer. In this case, the two low refractive index layers and two high refractive index layers may have the same refractive index.

[0041] The high refractive index layer here is, for example, a layer having a refractive index of 1.8 or more at a wavelength of 550 nm, and the low refractive index layer is a layer having a refractive index of 1.6 or less at a wavelength of 550 nm.

[0042] Half-tone masks used in the semiconductor manufacturing field are known as light-transmitting films that have both light absorption and insulating properties. Half-tone masks include Mo-SiO x An oxygen-deficient film such as a film is used. As an optically insulating and light-transmitting film having light absorption ability, there is a narrow band gap film used in the field of semiconductor manufacturing.

[0043] However, these films have a high ability to absorb light at short wavelengths in the visible light spectrum, which causes the transmitted light to have a yellowish tint, making them unsuitable for use as cover glasses for image display devices.

[0044] In this embodiment, the dielectric layer 32 has an increased Mo content, and the SiO x By including the dielectric layer 34 made of the above, it is possible to obtain a transparent substrate with an antireflection film that has light absorption ability, insulating properties, and excellent adhesion and strength.

[0045] The anti-reflection coated transparent substrate shown in FIG. 1 has the multilayer film 30 configured as described above, and therefore satisfies the characteristics of the anti-reflection coated transparent substrate according to this embodiment described above.

[0046] When the content of group B in the layer (ABO) 32 composed of a mixed oxide of at least one oxide selected from group A consisting of Mo and W and at least one oxide selected from group B consisting of Si, Nb, Ti, Zr, Ta, Al, Sn, and In is less than 80 mass%, b * This can prevent the value from exceeding 5. The content of group B is more preferably 70% by mass or less, and even more preferably 60% by mass or less.

[0047] In the case of a laminated structure in which three or more layers with different refractive indices are laminated, the layer (ABO) and the layer (SiO x In this case, the layer (ABO) and the layer (SiO x), it is necessary to select each layer so as to form a three-layer laminate structure of a low refractive index layer, a high refractive index layer, and a low refractive index layer, or a three-layer laminate structure of a high refractive index layer, a low refractive index layer, and a high refractive index layer, or a four-layer laminate structure of a low refractive index layer, a high refractive index layer, a low refractive index layer, and a high refractive index layer, or a four-layer laminate structure of a high refractive index layer, a low refractive index layer, a high refractive index layer, and a low refractive index layer.

[0048] However, the outermost layer is a layer (SiO x In order to obtain low reflectivity, it is preferable that the outermost layer is a layer (SiO x ) can be produced relatively easily. In addition, when forming an antifouling film, it is preferable to use a layer (SiO x ) is preferably formed thereon.

[0049] The layer (ABO) 32 is preferably amorphous. If it is amorphous, it can be produced at a relatively low temperature and is suitable for use when the transparent substrate is made of resin, for example, because the resin is not damaged by heat.

[0050] In the transparent substrate with a multilayer film according to this embodiment, at least one silicon oxide layer among the layers of the multilayer film has a moisture permeability of 300 g / m 2 If the moisture permeability is within the above range, it is possible to prevent moisture from entering from the outside, and therefore to prevent a change in transmittance of the anti-reflection film due to moisture intrusion.

[0051] The moisture permeability can be measured by the method specified in JIS Z 0208 (1976), as described in the examples below. The moisture permeability of the transparent substrate with a multilayer film according to this embodiment is 0.1 to 300 g / m 2 / day is preferred, and 0.1 to 100 g / m 2 / day is more preferable.

[0052] In the transparent substrate with a multilayer film according to this embodiment, at least one silicon oxide layer among the layers of the multilayer film preferably has a surface roughness (arithmetic mean height (Sa)) of 1.00 nm or less in a measurement area of ​​1 μm × 1 μm. If the surface roughness (arithmetic mean height (Sa)) is within this range, the silicon oxide layer becomes dense and can suppress the intrusion of moisture from the outside, thereby suppressing changes in the transmittance of the antireflection film due to the intrusion of moisture.

[0053] The surface roughness (arithmetic mean height (Sa)) in a measurement area of ​​1 μm×1 μm can be measured using a scanning probe microscope in accordance with the international standard ISO 25178, as described in the Examples below.

[0054] The surface roughness (arithmetic mean height (Sa)) of the silicon oxide layer of the multilayered transparent substrate according to this embodiment in a measurement area of ​​1 μm×1 μm is preferably 0.05 to 0.99 nm, more preferably 0.05 to 0.98 nm.

[0055] In the transparent substrate with a multilayer film according to this embodiment, at least one silicon oxide layer among the layers of the multilayer film preferably has a surface roughness (arithmetic mean height (Sa)) of 0.90 nm or less in a measurement area of ​​5 μm × 5 μm. If the surface roughness (arithmetic mean height (Sa)) is within this range, the silicon oxide layer becomes dense and can suppress the intrusion of moisture from the outside, thereby suppressing changes in the transmittance of the antireflection film due to the intrusion of moisture.

[0056] The surface roughness (arithmetic mean height (Sa)) in a measurement area of ​​5 μm×5 μm can be measured using a scanning probe microscope in accordance with the international standard ISO 25178, as described in the Examples below.

[0057] The surface roughness (arithmetic mean height (Sa)) of the silicon oxide layer of the multilayered transparent substrate according to this embodiment in a measurement area of ​​5 μm×5 μm is preferably 0.05 to 0.90 nm, more preferably 0.05 to 0.87 nm.

[0058] In the transparent substrate with a multilayer film according to this embodiment, at least one silicon oxide layer of the multilayer film preferably has a hardness of 5.0 GPa or more when measured under a load of 0.1 mN. If the hardness is within this range, the silicon oxide layer becomes dense and can suppress the intrusion of moisture from the outside, thereby suppressing changes in the transmittance of the antireflection film due to the intrusion of moisture.

[0059] The hardness of the silicon oxide layer can be determined by, for example, the following formula (1) as described in the examples below. surface strength It can be measured using a measuring device (nanoindenter).

[0060] The hardness of the silicon oxide layer of the multilayered transparent substrate according to this embodiment, measured by applying a load of 0.1 mN, is preferably 5.0 to 20.0 GPa, more preferably 5.2 to 15.0 GPa.

[0061] In the transparent substrate with a multilayer film according to this embodiment, at least one silicon oxide layer of the multilayer film preferably has a hardness of 6.6 GPa or more when measured under a load of 1 mN. If the hardness is within this range, the silicon oxide layer becomes dense and can suppress the intrusion of moisture from the outside, thereby suppressing changes in the transmittance of the antireflection film due to the intrusion of moisture.

[0062] The hardness of the silicon oxide layer can be determined by, for example, the hardness of the silicon oxide layer as described in the examples below. surface strength It can be measured using a measuring device (nanoindenter).

[0063] The hardness of the silicon oxide layer of the multilayered transparent substrate according to this embodiment, measured by applying a load of 1 mN, is preferably 6.6 to 20.0 GPa, more preferably 6.7 to 15.0 GPa.

[0064] In the transparent substrate with a multilayer film according to this embodiment, at least one silicon oxide layer among the layers of the multilayer film preferably has an elastic modulus of 70 GPa or more when measured under a load of 0.1 mN. If the elastic modulus is within this range, the silicon oxide layer becomes dense and can suppress the intrusion of moisture from the outside, thereby suppressing changes in the transmittance of the antireflection film due to the intrusion of moisture.

[0065] The elastic modulus of the silicon oxide layer can be determined by, for example, the following formula: surface strength It can be measured using a measuring device (nanoindenter).

[0066] The elastic modulus of the silicon oxide layer of the multilayered transparent substrate according to this embodiment, measured by applying a load of 0.1 mN, is preferably 70 to 200 GPa, more preferably 72 to 150 GPa.

[0067] In the transparent substrate with a multilayer film according to this embodiment, at least one silicon oxide layer among the layers of the multilayer film preferably has an elastic modulus of 81 GPa or more when measured under a load of 1 mN. If the elastic modulus is within this range, the silicon oxide layer becomes dense and can suppress the intrusion of moisture from the outside, thereby suppressing changes in the transmittance of the antireflection film due to the intrusion of moisture.

[0068] The elastic modulus of the silicon oxide layer is, as described in the examples below, surface strength The elastic modulus can be measured using a measuring device (nanoindenter) When a load of 1 mN is applied to the silicon oxide layer of the transparent substrate with a multilayer film according to this embodiment and measured, the elastic modulus is preferably 81 to 200 GPa, more preferably 81 to 150 GPa.

[0069] The transparent substrate with a multilayer film according to this embodiment will be further described below.

[0070] <Transparent base> The transparent substrate is preferably made of a material with a refractive index of 1.4 to 1.7, because this allows sufficient suppression of reflection at the bonding surface when optically bonding displays, touch panels, etc.

[0071] The transparent substrate is preferably a glass substrate or a resin substrate, and may be a laminate composed of a glass substrate and a resin substrate.

[0072] Glass having various compositions can be used as the glass substrate. For example, the glass used in this embodiment preferably contains sodium and has a composition that allows strengthening by molding and chemical strengthening treatment. Specific examples include aluminosilicate glass, soda-lime glass, borosilicate glass, lead glass, alkali barium glass, and aluminoborosilicate glass.

[0073] There are no particular limitations on the thickness of the glass substrate, but in order to effectively carry out chemical strengthening treatment when such treatment is to be carried out, the thickness is usually preferably 5 mm or less, and more preferably 3 mm or less.

[0074] The glass substrate is preferably chemically strengthened glass in order to increase the strength of the cover glass. When the glass substrate is subjected to an antiglare treatment, the chemical strengthening is carried out after the antiglare treatment and before the formation of the multilayer film.

[0075] The glass substrate is preferably subjected to an anti-glare treatment on the main surface on which the multilayer film is formed. The anti-glare treatment method is not particularly limited, and a method of subjecting the main surface of the glass to a surface treatment to form desired irregularities can be used.

[0076] Specifically, a method of chemically treating the main surface of the glass substrate, such as frosting, can be used. The frosting treatment involves immersing the glass substrate, which is the object to be treated, in a mixed solution of hydrogen fluoride and ammonium fluoride, and chemically treating the immersed surface.

[0077] In addition to such chemical treatment methods, other physical treatment methods may also be used, such as a so-called sandblasting method in which crystalline silicon dioxide powder, silicon carbide powder, or the like is sprayed onto the surface of the glass substrate with pressurized air, or polishing with a brush moistened with water and having crystalline silicon dioxide powder, silicon carbide powder, or the like attached thereto.

[0078] The resin substrate is preferably a resin film. Thermoplastic resins or thermosetting resins can be used as the resin film. Examples of suitable resins include polyvinyl chloride resin, polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl acetate resin, polyester resin, polyurethane resin, cellulose-based resin, acrylic resin, AS (acrylonitrile-styrene) resin, ABS (acrylonitrile-butadiene-styrene) resin, fluorine-based resin, thermoplastic elastomer, polyamide resin, polyimide resin, polyacetal resin, polycarbonate resin, modified polyphenylene ether resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polylactic acid-based resin, cyclic polyolefin resin, and polyphenylene sulfide resin.

[0079] Among these, cellulose-based resins are preferred, and triacetyl cellulose resins, polycarbonate resins, and polyethylene terephthalate resins are more preferred. These resins may be used alone or in combination of two or more.

[0080] The thickness of the film is not particularly limited, but is preferably 20 to 150 μm, more preferably 40 to 80 μm.

[0081] When a film is used as the transparent substrate 10, in this embodiment, a hard coat layer (not shown) or an anti-glare layer (not shown) may be disposed on the transparent substrate 10, and the multilayer film 30 may be disposed thereon.

[0082] Furthermore, as another embodiment, an anti-glare layer may be provided on the hard coat layer, and the multilayer film 30 may be provided on top of that.

[0083] The hard coat layer can be formed by applying a polymer resin solution.

[0084] The anti-glare layer is formed by forming an uneven shape on one side of the film to increase the haze and impart anti-glare properties. As with the hard coat layer, the anti-glare layer can be formed by coating a polymer resin solution. The anti-glare layer composition is formed by dispersing at least particulate material that itself has anti-glare properties in a solution in which a polymer resin is dissolved as a binder.

[0085] Examples of the particulate substance having antiglare properties include inorganic fine particles such as silica, clay, talc, calcium carbonate, calcium sulfate, barium sulfate, aluminum silicate, titanium oxide, synthetic zeolite, alumina, and smectite, as well as organic fine particles made of styrene resin, urethane resin, benzoguanamine resin, silicone resin, and acrylic resin.

[0086] Furthermore, the polymer resin used as the binder for the hard coat layer and the anti-glare layer may be a polymer resin made of a polyester resin, an acrylic resin, an acrylic urethane resin, a polyester acrylate resin, a polyurethane acrylate resin, an epoxy acrylate resin, or a urethane resin.

[0087] <Multilayer film> The above-mentioned multilayer film can be formed on the main surface of the transparent substrate by a known film formation method such as sputtering, vacuum deposition, coating, etc. That is, the dielectric layer or layers constituting the multilayer film are formed on the main surface of the transparent substrate by a known film formation method such as sputtering, vacuum deposition, coating, etc., depending on the lamination order.

[0088] Examples of sputtering methods include magnetron sputtering, pulse sputtering, AC sputtering, and digital sputtering.

[0089] For example, magnetron sputtering is a method in which a magnet is placed on the backside of a dielectric material, generating a magnetic field, causing gas ion atoms to collide with the surface of the dielectric material and be ejected, thereby forming a sputtering film with a thickness of several nanometers. Magnetron sputtering can form a continuous dielectric film that is an oxide or nitride of the dielectric material.

[0090] For example, digital sputtering differs from conventional magnetron sputtering in that it first forms an ultrathin metal film by sputtering, then oxidizes it by irradiating it with oxygen plasma, oxygen ions, or oxygen radicals. This process is repeated in the same chamber to form a thin film of metal oxide. In this case, the film-forming molecules are metal when they deposit on the substrate, so they are presumably more ductile than metal oxide films. Therefore, even with the same energy, the film-forming molecules are more likely to rearrange, resulting in a denser, smoother film.

[0091] The material of the anti-reflection film is not particularly limited, and various materials can be used as long as they can suppress light reflection. For example, the anti-reflection film may be configured by laminating a high-refractive index layer and a low-refractive index layer. Here, the high-refractive index layer is a layer with a refractive index of 1.8 or more at a wavelength of 550 nm, and the low-refractive index layer is a layer with a refractive index of 1.6 or less at a wavelength of 550 nm.

[0092] In the antireflection coated transparent substrate of this embodiment, the antireflection film may be provided on at least one main surface of the transparent substrate, but may be provided on both main surfaces of the transparent substrate as required.

[0093] <Anti-fouling film> The transparent substrate with a multilayer film of this embodiment may further have an anti-fouling film (also referred to as an "Anti Finger Print (AFP) film") on the multilayer film in order to protect the outermost surface of the film. The anti-fouling film may be composed of, for example, a fluorine-containing organosilicon compound.

[0094] The fluorine-containing organosilicon compound can be used without any particular limitation as long as it can impart antifouling, water repellency, and oil repellency. Examples of the fluorine-containing organosilicon compound include fluorine-containing organosilicon compounds having one or more groups selected from the group consisting of a polyfluoropolyether group, a polyfluoroalkylene group, and a polyfluoroalkyl group. The polyfluoropolyether group is a divalent group having a structure in which polyfluoroalkylene groups and etheric oxygen atoms are alternately bonded.

[0095] In addition, commercially available fluorine-containing organosilicon compounds having one or more groups selected from the group consisting of polyfluoropolyether groups, polyfluoroalkylene groups, and polyfluoroalkyl groups that can be preferably used include KP-801 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), KY178 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), KY-130 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), KY-185 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), OPTOOL (registered trademark) DSX, and OPTOOL AES (all trade names, manufactured by Daikin Corporation).

[0096] The antifouling film is laminated on the antireflection film. When antireflection films are formed on both main surfaces of a glass substrate or a resin substrate, antifouling films can be formed on both antireflection films, but an antifouling film may be laminated on only one of the surfaces. This is because the antifouling film only needs to be provided in a location where it may come into contact with a human hand, etc., and can be selected depending on the application, etc.

[0097] The transparent substrate with a multilayer film of this embodiment is suitable as a cover glass for an image display device, particularly as a cover glass for an image display device mounted on a vehicle, such as an image display device for a navigation system mounted on a vehicle. [Example]

[0098] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these. Examples 1 and 2 are working examples, and Examples 3 and 4 are comparative examples.

[0099] (Example 3) An antireflection film was formed on one main surface of the transparent substrate by the following method to prepare a transparent substrate with an antireflection film.

[0100] A triacetyl cellulose resin film (hereinafter referred to as TAC film) having a thickness of 40 μm was used as the transparent substrate.

[0101] Next, a dielectric layer (1) (metal oxide layer) was formed on one main surface of the transparent substrate by the following method: a target made by mixing niobium and molybdenum in a weight ratio of 60:40 and sintering it using a digital sputtering method was used; while maintaining the pressure at 0.2 Pa, a metal film of a small thickness was deposited using argon gas, which was then immediately oxidized using oxygen gas, repeatedly at high speed to form an oxide film; and a 10 nm Mo-Nb-O layer was formed on the main surface of the transparent substrate to which the diffusion layer was attached.

[0102] Next, as the dielectric layer (2) (silicon oxide layer), a silicon target was used in a digital sputtering method. While maintaining the pressure at 0.3 Pa, a silicon film was formed using argon gas, followed immediately by oxidation with oxygen gas, by repeating this process at high speed. A silicon oxide film with a thickness of 40 nm was then deposited on the Mo-Nb-O layer. x Here, when oxidizing with oxygen gas, the flow rate of oxygen was 500 sccm, and the input power of the oxidation source was 200 W.

[0103] Next, a target made by mixing and sintering niobium and molybdenum in a weight ratio of 60:40 was used as the dielectric layer (3) (metal oxide layer) by digital sputtering. While maintaining the pressure at 0.2 Pa, a metal film of a small thickness was deposited using argon gas, followed immediately by oxidation with oxygen gas, which was repeated at high speed to form an oxide film. A Mo-Nb-O layer of 120 nm thick was then formed on top of the silicon oxide layer.

[0104] Next, as the dielectric layer (4) (silicon oxide layer), a silicon target was used in a digital sputtering method. While maintaining the pressure at 0.3 Pa, a silicon film was formed using argon gas, followed immediately by oxidation with oxygen gas, by repeating this process at high speed. A silicon oxide film with a thickness of 100 nm was then deposited on the Mo-Nb-O layer. x Here, when oxidizing with oxygen gas, the flow rate of oxygen was 500 sccm, and the input power of the oxidation source was 200 W.

[0105] Furthermore, the spectral transmittance of the thus obtained anti-reflection film-coated transparent substrate was measured using a spectrophotometer (manufactured by Shimadzu Corporation, product name: SolidSpec-3700) before and after 500 hours had passed since it was placed in a 95°C reliability test tank, and the luminous transmittance (stimulus value Y specified in JIS Z 8701:1999) was calculated. The amount of change in luminous transmittance was calculated from the luminous transmittance before placement and the luminous transmittance after 500 hours had passed.

[0106] As a result, the change in luminous transmittance in Example 3 was 5%.

[0107] (Example 1) A transparent substrate with an antireflection film was produced in the same manner as in Example 3, except that the pressure when depositing the silicon oxide layers of the dielectric layer (2) and the dielectric layer (4) was changed to 0.1 Pa. The change in luminous transmittance in Example 1 was 2%.

[0108] (Example 2) A transparent substrate with an anti-reflection film was produced in the same manner as in Example 1, except that when the silicon oxide layers of the dielectric layer (2) and the dielectric layer (4) were formed, high-energy argon ions were emitted onto the film formation surface using a linear ion source (manufactured by ULVAC, Inc.) at an input voltage of 2 kV. The change in luminous transmittance in Example 2 was 1.5%.

[0109] (Example 4) In Example 3, no antireflection film was formed on one of the main surfaces of the transparent substrate.

[0110] (Measurement of moisture permeability of silicon oxide layer) For a 100 nm thick silicon oxide layer formed on a 40 μm thick triacetyl cellulose resin film measuring 100 mm long x 100 mm wide under the film-forming conditions of Examples 1, 2, and 3, moisture permeability was measured using a moisture permeability cup in accordance with JIS Z 0208 (1976) "Test method for moisture permeation of moisture-proof packaging materials." The moisture permeability was measured by sealing a moisture absorbent / calcium chloride (anhydrous) in the moisture permeability cup, and repeatedly weighing the cup at regular intervals (every 24 or 48 hours), and the increase in the cup's mass was evaluated as the amount of water vapor transmitted through it. The results of the evaluations below are shown in Table 1 below.

[0111] The silicon oxide layers having a thickness of 100 nm were formed on chemically strengthened glass substrates (Dragontrail: registered trademark, manufactured by AGC Corporation) having dimensions of 100 mm length x 100 mm width x 1.1 mm thickness under the film formation conditions of Examples 1, 2 and 3. The results of the evaluations performed on the silicon oxide layers are shown in Table 1 below.

[0112] (Surface roughness of silicon oxide layer (arithmetic mean height (Sa))) Measurements were performed using a measuring device [Hitachi High-Tech Corporation, device name: scanning probe microscope AFM5100N] with a measurement range of 1 μm × 1 μm (or 5 μm × 5 μm), an operation frequency of 1.2 Hz, and a tapping number of 256 × 256.

[0113] (Hardness of silicon oxide layer) Measurement equipment [manufactured by Elionix, equipment name: Table surface strength Measurements were carried out using a measuring device (nanoindenter) ESF-5000 Plus, applying a load of 0.1 mN (or 1 mN).

[0114] (Elastic modulus of silicon oxide layer) Measurement equipment [manufactured by Elionix, equipment name: Table surface strength Measurements were carried out using a measuring device (nanoindenter) ESF-5000 Plus, applying a load of 0.1 mN (or 1 mN).

[0115] [Table 1]

[0116] As shown in Table 1, the silicon oxide layers of Examples 1 and 2 have a moisture permeability of 300 g / m 2 / day or less, and the change in luminous transmittance was suppressed compared to Example 3.

[0117] Furthermore, in Table 1, the anti-reflection coated transparent substrates of Examples 1 and 2, in which the surface roughness (arithmetic mean height (Sa)) of the silicon oxide layer in a measurement range of 1 μm × 1 μm was 1.00 nm or less, had a dense silicon oxide layer that was able to prevent moisture from entering from the outside, and therefore the change in luminous transmittance was reduced compared to Example 3.

[0118] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. Furthermore, the components of the above-described embodiments may be combined in any manner without departing from the spirit of the invention.

[0119] This application is based on a Japanese patent application (Patent Application No. 2020-115919) filed on July 3, 2020, the contents of which are incorporated herein by reference. [Explanation of symbols]

[0120] 10 Transparent substrate 30 Multilayer film 32, 34 Dielectric layer

Claims

1. a multilayer film in which at least two layers having refractive indices different from each other are laminated on at least one of the main surfaces of a transparent substrate having two main surfaces, at least one layer of the multilayer film is a silicon oxide layer having a moisture permeability of 70 g / m 2 / day or less, and at least another layer of the multilayer film is composed mainly of a mixed oxide of at least one oxide selected from Group A consisting of Mo and W and at least one oxide selected from Group B consisting of Si, Nb, Ti, Zr, Ta, Al, Sn and In, and the content of the elements of Group B contained in the mixed oxide relative to the total of the elements of Group A contained in the mixed oxide and the elements of Group B contained in the mixed oxide is less than 80 mass %; A transparent substrate with an anti-reflection film, wherein all layers of the multilayer film are oxygen deficient.

2. The multilayer film is provided on at least one of the main surfaces of a transparent substrate having two main surfaces, and includes at least two layers having different refractive indices laminated thereon, and at least one silicon oxide layer of the multilayer film has a moisture permeability of 70 g / m ２ / day or less, At least one silicon oxide layer of the multilayer film has an elastic modulus of 70 GPa or more and 200 GPa or less; A transparent substrate with an anti-reflection film, wherein all layers of the multilayer film are oxygen deficient.

3. 3. The transparent substrate with an antireflection film according to claim 1, wherein at least one silicon oxide layer among the layers of the multilayer film has an arithmetic mean height (Sa) representing surface roughness in a measurement area of ​​1 μm×1 μm of 1.00 nm or less.

4. 3. The transparent substrate with an antireflection film according to claim 1, wherein at least one silicon oxide layer of the multilayer film has an arithmetic mean height (Sa) representing surface roughness in a measurement area of ​​5 μm×5 μm of 0.90 nm or less.

5. 5. The transparent substrate with an antireflection film according to claim 1, wherein at least one silicon oxide layer of the multilayer film has a hardness of 5.0 GPa or more.

6. 2. The transparent substrate with an antireflection film according to claim 1, wherein at least one silicon oxide layer of the multilayer film has an elastic modulus of 70 GPa or more.

7. The transparent substrate with an antireflection film according to any one of claims 1 to 6, further comprising an antifouling film on the multilayer film.

8. The transparent substrate with an antireflection film according to any one of claims 1 to 7, wherein the transparent substrate is a glass substrate.

9. The transparent substrate with an antireflection film according to any one of claims 1 to 7, wherein the transparent substrate is a resin substrate.

10. 8. The transparent substrate with an antireflection film according to claim 1, wherein the transparent substrate is a laminate composed of a glass substrate and a resin substrate.

11. The transparent substrate with an anti-reflection film according to claim 10 , wherein the glass is chemically strengthened.

12. 12. The transparent substrate with an antireflection film according to claim 1, wherein the transparent substrate has an antiglare treatment applied to a main surface on the side having the multilayer film.

13. An image display device comprising the anti-reflection coated transparent substrate according to any one of claims 1 to 12.

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