TW202601159A - Optical laminate, method of manufacturing optical laminate and article - Google Patents

Abstract

The present invention provides an optical laminate and a method for manufacturing the optical laminate, wherein the optical laminate exhibits excellent alkali resistance over a long period of time. The optical laminate of this invention comprises a substrate, a high refractive index layer disposed on the substrate directly or interposed of other layers, a low refractive index layer formed on the high refractive index layer and containing _SiO2 as the main component, and an antifouling layer formed on the low refractive index layer. The manufacturing method of the optical laminate of this invention includes a high refractive index layer formation step, a low refractive index layer formation step of forming the low refractive index layer in a dry atmosphere, a plasma treatment step of plasma treating the low refractive index layer, and an antifouling layer formation step of forming an antifouling layer on the surface. In the plasma treatment step, in an environment where a mixture of water vapor and argon is introduced, the heat exchanger operates at a temperature of 4400 W/ ^m² or higher and 18000 W/m². The low refractive index layer is plasma-treated with an electrode power density of ² or less; and the binding energy of _SiO2 on the self-fouling layer side, as measured by X-ray photoelectron analysis (ESCA), is less than 103.25 eV.

Description

Optical laminates, methods for manufacturing optical laminates, and articles thereof.

This invention relates to an optical laminate, a method for manufacturing an optical laminate, and an article thereof. This application is based on Japanese Patent Application No. 2024-023257 filed on February 19, 2024, the contents of which are incorporated herein by reference.

Anti-reflective films are used in various devices to prevent surface reflections. Examples include automotive films for head-up displays and touch panels for smartphones. A representative anti-reflective film is an optical laminate formed as follows: a hard coating is formed on a transparent substrate; high-refractive-index layers and low-refractive-index layers are alternately formed on the hard coating as optical functional layers; and an anti-fouling layer containing fluorine compounds is formed on the optical functional layers.

As a method for manufacturing an antireflective film composed of an optical laminate, for example, the following method is known: a resin solution containing microparticles with different refractive indices is prepared, layers with different refractive indices are sequentially coated with the resin solution, and the layer is dried to obtain a laminate (e.g., Patent 1). Furthermore, methods are known for forming an optical functional layer on a substrate by sputtering, evaporation, etc., and then forming an antifouling layer by evaporation, etc. (e.g., Patents 2, 3, 4, 5). In patent documents 2 and 3, the outermost layer of the optical functional layer that is furthest from the substrate is formed as a low refractive index layer containing _SiO2 as the main component. The low refractive index layer is formed by sputtering. The antifouling layer containing fluorine compounds is formed on the low refractive index layer by coating or evaporation after the low refractive index layer is formed.

Furthermore, Patent Documents 2 and 3 disclose the following: To form an optically laminate with high adhesion between organic and inorganic layers, such as an antifouling layer, reactive sputtering is performed during the formation of the inorganic layer, using water vapor as the reactive gas. [Prior Art Documents][Patent Documents]

[Patent Document 1] Japanese Patent Application Publication No. 2015-197634 [Patent Document 2] Japanese Patent Application Publication No. 2012-251193 [Patent Document 3] Japanese Patent Application Publication No. 2014-43600 [Patent Document 4] Japanese Patent Application Publication No. 2009-117569 [Patent Document 5] International Publication No. 2015/097898

[Problem Solved by the Invention] Anti-reflective films are expected to be touched by users, during which time dirt such as sebum or dust may adhere. Sebum-induced dirt, in particular, can affect visibility. The fluorine-based compound constituting the anti-fouling layer combines with the substrate constituting the inorganic layer to inhibit this dirt buildup. When dirt adheres to the surface of the anti-reflective film, maintenance is considered using alkaline chemicals to remove the dirt. Since head-up displays or smartphone touch panels using anti-reflective films are used for extended periods, long-term alkalinity resistance is required.

In cases where an inorganic layer is formed by sputtering in a steam environment, as described in Patents 1 and 2, it is assumed that hydroxyl groups are formed within the inorganic layer. It is known that inorganic layers containing oxides such as _SiO₂ dissolve due to the hydrolysis of _H₂O . As the inorganic layer dissolves, optical properties such as the refractive index change. Furthermore, the dissolution of the inorganic layer is facilitated by the substitution of hydroxyl groups by alkali metals with hydrogen elements.

The present invention is made in view of the above circumstances, and aims to provide an optical laminate that exhibits excellent alkali resistance over a long period of time, a method for manufacturing the optical laminate, and an article thereof.

[Technical Means for Solving the Problem] The inventors have discovered that by forming hydroxyl groups that bond with the substrate of the inorganic layer on the outermost surface of the inorganic layer, it is easier to add substrate to the antifouling layer. However, when too many hydroxyl groups are formed inside the inorganic layer, excellent alkali resistance is sometimes not obtained. Therefore, to solve the above problems, the present invention provides the following method.

(1) The optical laminate manufactured by the method of manufacturing an optical laminate of one form of the present invention comprises: a substrate; a high refractive index layer disposed on the substrate directly or interposed of other layers; and SiO2 formed on the high refractive index layer. _2. A low refractive index layer as the main component; and an antifouling layer formed on the low refractive index layer; the manufacturing method of the optical laminate includes a high refractive index layer forming step of forming a high refractive index layer, a low refractive index layer forming step of forming the low refractive index layer in a dry atmosphere, a plasma treatment step of plasma treatment of the low refractive index layer, and an antifouling layer forming step of forming an antifouling layer on the surface, wherein in the plasma treatment step, the low refractive index layer is plasma treated in an environment in which a mixture of water vapor and argon is introduced, and the electrode power density is 4400 W/ ^m² or higher and 18000 W/ ^m² or lower.

(2) In the manufacturing method of the optical laminate in (1) above, in the plasma processing step above, the flow rate ratio of water vapor in the mixed gas of water vapor and argon can also be set to 10% or more and 90% or less.

(3) The electrode power density in the plasma treatment steps of (1) or (2) above can also be above 7000 W/m ² and below 14000 W/m ² .

(4) In the manufacturing method of the optical laminate in (1) to (3) above, the low refractive index layer can also be formed by sputtering in the step of forming the low refractive index layer.

(5) In the manufacturing method of the optical laminate in (1) to (4) above, the antifouling layer can also be formed by vapor deposition in the antifouling layer forming step, and the antifouling layer contains a compound having alkoxysilyl and fluorine-modified organic groups.

(6) In the manufacturing method of the optical laminate in (1) to (5) above, in the plasma treatment step above, the ratio of _H2O in the atmosphere in the space where the low refractive index layer is plasma treated can be 6.5% or more and 50% or less.

(7) One form of optical laminate of the present invention comprises: a substrate; a high refractive index layer formed on the substrate directly or through other layers; a low refractive index layer formed on the high refractive index layer and containing _SiO2 as the main component; and an antifouling layer formed on the low refractive index layer; after dropping 0.1 (mol/L) NaOH aqueous solution and standing at 55°C for 4 hours, the ΔE value expressed by the following formula (1) is 8 or less. ΔE ^* _ab ＝{(L ^* ₂ －L ^* ₁ ) ² ＋(a ^* ₂ －a ^* ₁ ) ² ＋(b ^* ₂ －b ^* ₁ ) ² } ^1/2・・・(1)(where, L ^* ₁ : brightness before the NaOH aqueous solution is added, L ^* ₂ : brightness after a specific time has elapsed since the NaOH aqueous solution was added, a ^* ₁ : chromaticity before the NaOH aqueous solution was added, a ^* ₂ : chromaticity after a specific time has elapsed since the NaOH aqueous solution was added, b ^* ₁ : chromaticity before the NaOH aqueous solution was added, b ^* ₂ : chromaticity after a specific time has elapsed since the NaOH aqueous solution was added)

(8) In the optical laminate described in (7) above, the binding energy of _SiO2 measured by X-ray photoelectron analysis (ESCA) from the antifouling layer side can also be below 103.25 eV.

(9) In the optical laminates of (7) and (8) above, the high refractive index layer may contain an oxide of the first metal, the low refractive index layer may contain an oxide of the second metal, and the metal elements detected by the determination using ESCA may be only the first metal element and the second metal element.

(10) The optical laminates of (7) and (8) above may also have a close-fitting layer between the substrate and the high refractive index layer, wherein the high refractive index layer contains an oxide of a first metal, the low refractive index layer contains an oxide of a second metal, the close-fitting layer contains an oxide of a third metal, and the metal elements detected by ESCA measurement are only the first metal element, the second metal element and the third metal element. (11) An article of one form of the present invention has an optical laminate as described in any one of (7) to (9) above.

[Effects of the Invention] According to the present invention, an optical laminate exhibiting excellent alkali resistance over a long period of time, a method for manufacturing the optical laminate, and an article thereof can be provided.

The present invention will now be described in detail with appropriate reference to the accompanying drawings. To facilitate understanding of the features of the invention, the drawings used in the following description may show enlarged portions of the features, and the dimensions and proportions of the constituent elements may sometimes differ from the actual situation. The materials and dimensions illustrated in the following description are examples only; the invention is not limited to these examples and may be appropriately modified and implemented within the scope of achieving its intended effect.

[Optical Laminate] FIG1 is a cross-sectional view showing an example of the configuration of an optical laminate according to an embodiment of the present invention. The optical laminate 101 shown in FIG1 is formed by sequentially laminating a transparent substrate 11, a hard coating layer 12, a bonding layer 13, an optical functional layer 14 including a high refractive index layer 14a and a low refractive index layer 14b, and an antifouling layer 15. In the optical laminate 101, the high refractive index layer 14a is located close to the transparent substrate 11, and the low refractive index layer 14b is farther away from the transparent substrate 11 than the high refractive index layer 14a.

Figure 2 is a cross-sectional view of another example of the optical laminate shown in Figure 1. The optical laminate 102 shown in Figure 2 has an optical functional layer 14 with alternating layers of a plurality of high-refractive-index layers 14a and low-refractive-index layers 14b. In the optical laminate 102, the high-refractive-index layer 14a is disposed closest to the transparent substrate 11, and the low-refractive-index layer 14b is disposed furthest from the transparent substrate 11. That is, in either Figure 1 or Figure 2, the antifouling layer 15 is in contact with the low-refractive-index layer 14b of the optical functional layer 14. The low-refractive-index layer 14b is a layer containing _SiO2 as the main component.

The optical laminate of this invention comprises a substrate (transparent substrate 11), a high refractive index layer 14a formed on the substrate directly or intervening in other layers, a low refractive index layer 14b formed on the high refractive index layer 14a and containing _SiO2 as the main component, and an antifouling layer 15 formed on the low refractive index layer 14b. After dropping 0.1 (mol/L) NaOH aqueous solution and standing at 55°C for 4 hours, the ΔE value expressed by the following formula (1) is 8 or less. The optical properties of the optical laminate, such as brightness and chromaticity, are measured by an integrating sphere spectrophotometer as described below.

ΔE ^* _ab ＝{(L ^* ₂ －L ^* ₁ ) ² ＋(a ^* ₂ －a ^* ₁ ) ² ＋(b ^* ₂ －b ^* ₁ ) ² } ^1/2・・・(1)(where, L ^* ₁ : brightness before the NaOH aqueous solution is added, L ^* ₂ : brightness after a specific time has elapsed since the NaOH aqueous solution was added, a ^* ₁ : chromaticity before the NaOH aqueous solution was added, a ^* ₂ : chromaticity after a specific time has elapsed since the NaOH aqueous solution was added, b ^* ₁ : chromaticity before the NaOH aqueous solution was added, b ^* ₂ : chromaticity after a specific time has elapsed since the NaOH aqueous solution was added)

When a high-refractive-index layer 14a is formed on a substrate while other layers are interposed in the optical laminate, a hard coating layer 12 and a bonding layer 13 are formed between the substrate and the high-refractive-index layer 14a, for example. Optical laminates 101 and 102, for example, include a transparent substrate 11, a hard coating layer 12, a bonding layer 13, an optical functional layer 14, and an antifouling layer 15. In the optical laminate, for example, the binding energy of _SiO₂ measured by X-ray photoelectron analysis (ESCA) from the antifouling layer 15 side is 103.25 eV or less.

The transparent substrate 11 may be formed of a transparent material that allows light to pass through the visible light range. For example, a plastic film may preferably be used as the transparent substrate 11. Specific examples of materials constituting the plastic film include: polyester resins, acetate resins, polyether ether resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, polyvinyl chloride resins, polyvinylidene chloride resins, polystyrene resins, polyvinyl alcohol resins, polyarylate resins, and polyphenylene sulfide resins.

Furthermore, the term "transparent material" in this invention refers to a material with a light transmittance of 80% or more in the wavelength range, without impairing the effectiveness of this invention. Also, in this embodiment, "(meth)acrylic acid" means methacrylic acid and acrylic acid.

The transparent substrate 11 may also contain reinforcing materials, provided that the optical properties are not severely impaired. Reinforcing materials may include, for example, cellulose nanofibers or nano-silica. Polyester resins, acetate resins, polycarbonate resins, and polyolefin resins are particularly preferred as reinforcing materials. Specifically, triacetyl cellulose (TAC) substrates are preferred as reinforcing materials. Furthermore, the transparent substrate 11 can also be used as a glass film, which is an inorganic substrate.

If the plastic film is a TAC substrate, when the hard coating layer 12 is formed on one side, a permeation layer is formed by the partial permeation of one of the components constituting the hard coating layer 12. As a result, the adhesion between the transparent substrate 11 and the hard coating layer 12 becomes good, and the generation of interference fringes caused by the difference in refractive index between the layers can be suppressed.

The transparent substrate 11 can also be a film that has been endowed with optical and/or physical functions. Examples of films with optical and/or physical functions include polarizing plates, phase difference compensation films, thermal line blocking films, transparent conductive films, brightness enhancement films, and gas barrier enhancement films.

The thickness of the transparent substrate 11 is not particularly limited, but is preferably 25 μm or more. The film thickness of the transparent substrate 11 is more preferably 40 μm or more. If the thickness of the transparent substrate 11 is 25 μm or more, the rigidity of the substrate itself can be ensured, and wrinkles are less likely to occur even when stress is applied to the optical laminates 101 and 102. Furthermore, if the thickness of the transparent substrate 11 is 25 μm or more, wrinkles are less likely to occur even when a hard coating layer 12 is continuously formed on the transparent substrate 11, reducing manufacturing concerns and thus being preferable. If the thickness of the transparent substrate 11 is 40 μm or more, wrinkles are even less likely to occur, and therefore is preferable.

When using rollers during manufacturing, the thickness of the transparent substrate 11 is preferably 1000 μm or less, and more preferably 600 μm or less. If the thickness of the transparent substrate 11 is 1000 μm or less, it is easier to roll the optical laminates 101 and 102 during and after manufacturing into a roller shape, allowing for efficient manufacturing of the optical laminates 101 and 102. Furthermore, if the thickness of the transparent substrate 11 is 1000 μm or less, it is possible to achieve thin-film and lightweight optical laminates 101 and 102. If the thickness of the transparent substrate 11 is 600 μm or less, it is even more efficient to manufacture the optical laminates 101 and 102, and further thin-film and lightweight manufacturing is possible, which is therefore preferable.

Alternatively, the surface of the transparent substrate 11 can be pre-treated with etching processes such as sputtering, corona discharge, ultraviolet irradiation, electron beam irradiation, chemical treatment, oxidation, and/or primer treatment. By performing these treatments in advance, the adhesion to the hard coating layer 12 formed on the transparent substrate 11 can be improved. Furthermore, it is also preferable that, before forming the hard coating layer 12 on the transparent substrate 11, the surface of the transparent substrate 11 can be cleaned by solvent cleaning, ultrasonic cleaning, etc., as needed, to remove dust and purify the surface of the transparent substrate 11.

The hard coating 12 can be any known hard coating. The hard coating 12 can be composed solely of adhesive resin, or it can include adhesive resin and fillers within the scope of not impairing transparency. The fillers can be composed of organic materials, inorganic materials, or a combination of organic and inorganic materials.

The adhesive resin used in the hard coating 12 is preferably transparent, such as free radiation-curing resin, thermoplastic resin, or thermosetting resin, which are resins that are cured by ultraviolet light or electron beams.

Examples of free radiation-curing resins used as adhesive resins in hard coating 12 include ethyl methacrylate, ethylhexyl methacrylate, styrene, methylstyrene, and N-vinylpyrrolidone. Furthermore, examples of compounds that are free radiation-curing resins having two or more unsaturated bonds include: trihydroxymethylpropane tri(meth)acrylate, tripropylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trihydroxymethylpropane tri(meth)acrylate, and di-trihydroxymethylpropane tetra(meth)acrylate. Multifunctional compounds such as pentaerythritol pentamethacrylate, pentaerythritol octamethacrylate, pentaerythritol decamethacrylate, trimethocyanate trimethacrylate, dimethocyanate dimethacrylate, polyester trimethacrylate, polyester dimethacrylate, bisphenol dimethacrylate, diglycerol tetramethacrylate, diamond dimethacrylate, isomethacrylate, dicyclopentane dimethacrylate, tricyclodecane dimethacrylate, and di-trihydroxymethylpropane tetramethacrylate are also mentioned. Among these, pentaerythritol triacrylate (PETA), pentaerythritol hexaacrylate (DPHA), and pentaerythritol tetraacrylate (PETTA) are preferred. Furthermore, "(meth)acrylate" refers to methacrylates and acrylates. Furthermore, free radiation-curing resins can also be made by modifying the above compounds with PO (propylene oxide), EO (ethylene oxide), CL (caprolactone), etc.

Thermoplastic resins used as adhesive resins for hard coating 12 include, for example, styrene-based resins, (meth)acrylic resins, vinyl acetate resins, vinyl ether resins, halogenated resins, alicyclic olefin resins, polycarbonate resins, polyester resins, polyamide resins, cellulose derivatives, silicone resins, and rubber or elastomers. Preferably, the above-mentioned thermoplastic resins are amorphous and soluble in organic solvents (especially common solvents that can dissolve multiple polymers and curing compounds). In particular, from the perspective of transparency and weather resistance, styrene-based resins, (meth)acrylic resins, alicyclic olefin resins, polyester resins, and cellulose derivatives (cellulose esters, etc.) are preferred.

Examples of thermosetting resins used as adhesive resins for hard coating 12 include: phenolic resins, urea resins, diallyl phthalate resins, melamine resins, guanidine resins, unsaturated polyester resins, polyurethane resins, epoxy resins, amino alkyd resins, melamine-urea cocondensate resins, silicone resins, and polysiloxane resins (including all sesquisiloxanes such as cage-like and ladder-like forms).

The hard coating 12 may contain organic resins and inorganic materials, or a mixture of organic and inorganic materials. For example, it may be formed using a sol-gel method. Inorganic materials may include, for example, silicon oxide, aluminum oxide, zirconium oxide, and titanium oxide. Organic materials may include, for example, acrylic resins. Regarding the fillers contained in the hard coating 12, from the viewpoints of anti-glare properties, adhesion to the optical functional layer 14 described below, and anti-blocking properties, various fillers may be selected according to the intended use of the optical laminates 101 and 102. Specifically, known fillers such as silicon oxide (oxide of Si) particles, aluminum oxide (oxide of aluminum) particles, and organic microparticles may be used.

The hard coating layer 12 may also include, for example, an adhesive resin and silica particles and/or alumina particles as fillers. By dispersing the silica particles and/or alumina particles as fillers in the hard coating layer 12, fine irregularities can be formed on the surface of the hard coating layer 12. These silica particles and/or alumina particles may also be exposed on the surface of the hard coating layer 12 on the side of the optical functional layer 14. In this case, the adhesive resin of the hard coating layer 12 is firmly bonded to the optical functional layer 14. Therefore, the adhesion between the hard coating layer 12 and the optical functional layer 14 is improved, the hardness of the hard coating layer 12 becomes higher, and the scratch resistance of the optical laminates 101 and 102 becomes better.

The average particle size of the silica particles and/or alumina particles used as fillers in the hard coating layer 12 is, for example, 800 nm or less, preferably 780 nm or less, and even more preferably 100 nm or less.

From the viewpoint of improving the anti-glare properties of optical laminates 101 and 102, organic microparticles can be used as fillers contained in the hard coating layer 12. Examples of organic microparticles include acrylic resins. The particle size of the organic microparticles is preferably 10 μm or less, more preferably 5 μm or less, and particularly preferably 3 μm or less. To impart strength to the hard coating layer 12, various reinforcing materials can be used as fillers contained in the hard coating layer 12 without compromising its optical properties. Examples of reinforcing materials include cellulose nanofibers.

The thickness of the hard coating layer 12 is not particularly limited, but it is preferably 0.5 μm or more, and more preferably 1 μm or more. The thickness of the hard coating layer 12 is preferably 100 μm or less. If the thickness of the hard coating layer 12 is 0.5 μm or more, sufficient hardness can be obtained, and scratches are less likely to occur during manufacturing. Furthermore, if the thickness of the hard coating layer 12 is 100 μm or less, thinner and lighter optical laminates 101 and 102 can be achieved. Also, if the thickness of the hard coating layer 12 is 100 μm or less, microcracks in the hard coating layer 12 caused by bending of the optical laminates 101 and 102 during manufacturing are less likely to occur, resulting in better manufacturability.

The hard coating layer 12 can be a single layer or formed by stacking multiple layers. Furthermore, the hard coating layer 12 can be endowed with known functions such as ultraviolet absorption, antistatic properties, refractive index adjustment, and hardness adjustment. Moreover, the functions endowed to the hard coating layer 12 can be assigned to a single hard coating layer or separately to multiple layers.

The bonding layer 13 is formed to ensure good adhesion between the transparent substrate 11 (organic film) or the hard coating layer 12 and the optical functional layer 14 (inorganic film). In the optical laminates 101 and 102 shown in Figures 1 and 2, a bonding layer 13 is provided between the hard coating layer 12 and the optical functional layer 14. The bonding layer 13 functions to ensure good adhesion between the hard coating layer 12 and the optical functional layer 14. Preferably, the bonding layer 13 is a metal oxide or metal containing oxygen vacancies. An oxygen vacancies metal oxide refers to a metal oxide with an insufficient number of oxygen atoms compared to its stoichiometric composition. Examples of oxygen-deficient metal oxides include SiOx, AlOx, TiOx, ZrOx, CeOx, MgOx, ZnOx, TaOx, SbOx, SnOx, and MnOx. Examples of metals include Si, Al, Ti, Zr, Ce, Mg, Zn, Ta, Sb, Sn, Mn, and In. In this embodiment, the metal elements constituting the bonding layer 13, and the metal elements in the metal oxides, are sometimes referred to as third metal elements. The bonding layer 13 may also be, for example, SiOx with x values exceeding 0 but not reaching 2.0. Furthermore, the bonding layer may also be formed from a mixture of multiple metals or metal oxides.

From the perspective of maintaining the adhesion between the substrate and the optical functional layer 14 and obtaining good optical properties, the thickness of the adhesion layer 13 is preferably greater than 0 nm and less than 20 nm, and more preferably greater than 1 nm and less than 10 nm.

The optical functional layer 14 is a laminate that exhibits anti-reflective properties. The optical functional layer 14 is formed by sequentially and alternately depositing a high-refractive-index layer 14a and a low-refractive-index layer 14b starting from the transparent substrate 11. In the example shown in Figure 1, it contains a total of 2 layers, and in the example shown in Figure 2, it contains a total of 4 layers. The number of high-refractive-index layers 14a and low-refractive-index layers 14b is not particularly limited and can be any number.

Since the optical functional layer 14 is composed of alternating layers of low-refractive-index layer 14b and high-refractive-index layer 14a, light incident from the anti-fouling layer 15 interferes with each other due to the optical functional layer 14, thereby reducing the intensity of reflected light and exerting an anti-reflection function. Therefore, an anti-reflection function can be obtained to prevent light incident from the anti-fouling layer 15 from being reflected in a single direction.

The low refractive index layer 14b is, for example, a layer with _SiO2 (an oxide of Si) as the main component. The _SiO2 monolayer film is colorless and transparent. In this embodiment, the main component of the low refractive index layer 14b means the component contained in the low refractive index layer 14b at a mass percentage of 50% or more.

When the low-refractive-index layer 14b is a layer mainly composed of Si oxide, it may contain less than 50% by mass of other elements, and may also be composed of Si oxide. In this embodiment, the metal element contained in the metal oxide of the low-refractive-index layer 14b as a main component, namely silicon, is sometimes referred to as the second metal element. The content of elements different from Si oxide is preferably less than 10%. Other elements may be included, for example, for the purpose of improving durability, for the purpose of improving hardness, Zr, Al, or N may be included, and for the purpose of improving alkali resistance, Zr or Al may be included.

The refractive index of the high refractive index layer 14a is preferably 2.00–2.60, _and more preferably 2.10–2.45. Examples of dielectrics used in the high refractive index layer 14a include: niobium pentoxide ( _Nb₂O₅ , refractive index 2.33), titanium oxide ( _TiO₂ , refractive index 2.33–2.55), tungsten oxide ( _WO₃ , refractive index 2.2), cerium oxide ( _CeO₂ , refractive index 2.2), tantalum pentoxide ( _Ta₂O₅ , refractive index 2.16), zinc oxide (ZnO, refractive index 2.1), indium tin oxide ( _ITO , refractive index 2.06), and zirconia oxide ( _ZrO₂ , refractive index 2.2). In this embodiment, metal elements such as niobium, titanium, tungsten, cerium, tantalum, zinc, and zirconium, which are included as main components in the metal oxide of the high refractive index layer, are sometimes referred to as the first metal element. When it is desired to impart conductive properties to the high refractive index layer 14a, ITO or indium zinc oxide (IZO) may be selected, for example.

The optical functional layer 14 is preferably _, for example, a layer containing niobium pentoxide ( _Nb₂O₅ , refractive index 2.33) as the high refractive index layer 14a, and a layer containing _SiO₂ as the low refractive index layer 14b.

The thickness of the low-refractive-index layer 14b can be in the range of 1 nm or more and 200 nm or less, and can be appropriately selected according to the wavelength region where anti-reflection function is required. The thickness of the high-refractive-index layer 14a can be, for example, 1 nm or more and 200 nm or less, and can be appropriately selected according to the wavelength region where anti-reflection function is required. The thicknesses of the high-refractive-index layer 14a and the low-refractive-index layer 14b can be appropriately selected according to the design of the optical functional layer 14. In the optical laminate 102, for example, starting from the side of the close-packed layer 13, a high-refractive-index layer 14a of 5-50 nm, a low-refractive-index layer 14b of 10-80 nm, a high-refractive-index layer 14a of 20-200 nm, and a low-refractive-index layer 14b of 50-200 nm can be formed sequentially. In the optical laminate 101, the thickness of the high refractive index layer 14a and the low refractive index layer 14b can be selected to achieve any thickness.

In the optical functional layer 14, a low refractive index layer 14b is disposed on the side of the antifouling layer 15. That is, in the optical functional layer 14, high refractive index layers 14a and low refractive index layers 14b are alternately disposed such that the layer in contact with the antifouling layer 15 is the low refractive index layer 14b. When the low refractive index layer 14b of the optical functional layer 14 is in contact with the antifouling layer 15, the anti-reflective performance of the optical functional layer 14 is better than when the high refractive index layer 14a is in contact with the antifouling layer 15. Furthermore, as explained in detail below, in the optical laminates 101 and 102, the Si element on the outermost surface of the low refractive index layer 14b located to the side of the antifouling layer 15 is bonded to the fluorine organic compound contained in the antifouling layer 15 via oxygen atoms.

An anti-fouling layer 15 is formed on the outermost surface of the optical functional layer 14 to prevent contamination of the optical functional layer 14. Furthermore, when applied to touch panels, the anti-fouling layer 15 suppresses wear on the optical functional layer 14 through its abrasion resistance. In this embodiment, the anti-fouling layer 15 is formed by vacuum-depositing a fluorine-based organic compound as the anti-fouling material on one side of the low-refractive-index layer 14b constituting the optical functional layer 14. In this embodiment, because the anti-fouling material contains a fluorine-based organic compound, the optical layers 101 and 102 exhibit better abrasion resistance and alkali resistance.

As the fluorinated organic compound constituting the antifouling layer 15, compounds containing fluorinated modified organic groups and reactive silyl groups (such as alkoxysilanes) are preferred. The antifouling layer 15 is preferably a compound containing fluorinated modified organic groups such as alkoxysilyl groups, perfluoropolyether groups, or fluoroalkyl groups. Commercially available examples include OPTOOL DSX (manufactured by Daikin Co., Ltd.) and KY-100 Series (manufactured by Shin-Etsu Chemical Co., Ltd.).

When a fluorinated organic compound containing fluorine-modified organic groups and reactive silyl groups (e.g., alkoxysilanes) is used as the fluorine-based organic compound constituting the antifouling layer 15, and a low-refractive-index layer 14b containing _SiO2 is used as the optical functional layer 14 in contact with the antifouling layer 15, siloxane bonds are formed between the silanol groups generated from the reactive silyl groups of the fluorine-based organic compound and the hydroxyl groups present on the _SiO2 surface. Therefore, the adhesion between the optical functional layer 14 and the antifouling layer 15 becomes better, which is preferable.

The optical thickness of the anti-fouling layer 15 can be in the range of 1 nm or more and 20 nm or less, preferably 3 nm or more and 10 nm or less. If the thickness of the anti-fouling layer 15 is 1 nm or more, the wear resistance can be sufficiently ensured when the optical laminates 101 and 102 are applied to touch panels, etc. Furthermore, if the thickness of the anti-fouling layer 15 is 3 nm or more, the liquid resistance of the optical laminates 101 and 102 is improved. Furthermore, if the thickness of the anti-fouling layer 15 is 20 nm or less, the time required for evaporation can be short, allowing for efficient manufacturing.

In the optical laminates 101 and 102 constructed as described above, the binding energy of _SiO2 measured by X-ray photoelectron analysis (ESCA) from the antifouling layer 15 side of the optical laminates 101 and 102 is, for example, 103.25 eV or less. This binding energy is, for example, 103.00 eV or more, more preferably 103.01 eV or more and 103.15 eV or less. It is known that the binding energy of _SiO2 is typically 103.6 eV, and a lower value is used in the optical laminates 101 and 102.

Furthermore, regarding the improvement of alkali resistance, it is ideal to measure the width of the antifouling layer 15 of the optical laminates 101 and 102 using X-ray photoelectron analysis (ESCA), and to detect no metal elements other than the metal oxides used in the optical laminates. That is, when the high refractive index layer 14a contains an oxide of a first metal and the low refractive index layer 14b contains an oxide of a second metal different from the first metal, the metal elements detected by ESCA are preferably only the first and second metal elements. When the optical laminate further has a close-packed layer 13 and the close-packed layer contains an oxide of a third metal, the metal elements detected by ESCA are preferably only the first, second, and third metal elements. For example, in an optical laminate where the close-packed layer is SiOx, the high refractive index layer is an _{Nb₂O₅ film} , and the low refractive index layer is a _SiO₂ film, it is preferable that no metal elements other than Si and Nb are detected. The metal elements that can be incorporated into this optical laminate, apart from the metal oxides used in the optical laminate, are mainly the metals used in the plasma treatment electrodes, such as Al, Zr, and Ti.

As explained in detail below, in optical laminates 101 and 102, after the formation of the low refractive index layer 14b, the low refractive index layer is subjected to plasma treatment in an environment with water vapor and argon. That is, by plasma treatment of the low refractive index layer in the presence of _H2O and Ar, a portion of the siloxane bonds of Si and _O on the outermost surface of SiO2 constituting the low refractive index layer 14b is cut off and reacts with _H2O in the atmosphere during plasma treatment to generate hydroxyl groups bonded to Si. Subsequently, these groups combine with the fluorine-based organic compounds constituting the antifouling layer 15.

Optical laminates 101 and 102 exhibit high alkali resistance over a long period. Specifically, after adding 0.1 mol/L NaOH aqueous solution and allowing it to stand at 55°C for 4 hours, the ΔE value (refer to formula (1) below) is 8 or less, preferably 4 or less. If the ΔE value does not change after 4 hours from the addition of the NaOH aqueous solution, it is 0. The ΔE value of optical laminates 101 and 102 is 0 or more, or even 0.5 or more.

ΔE ^* _ab ＝{(L ^* ₂ －L ^* ₁ ) ² ＋(a ^* ₂ －a ^* ₁ ) ² ＋(b ^* ₂ －b ^* ₁ ) ² } ^1/2・・・(1)(In formula (1), L ^* ₁ : brightness before the NaOH aqueous solution is added, L ^* ₂ : brightness after a specific time has elapsed since the NaOH aqueous solution was added, a ^* ₁ : chromaticity before the NaOH aqueous solution is added, a ^* ₂ : chromaticity after a specific time has elapsed since the NaOH aqueous solution was added, b ^* ₁ : chromaticity before the NaOH aqueous solution is added, b ^* ₂ : chromaticity after a specific time has elapsed since the NaOH aqueous solution was added)

[Article] Figure 3 is a perspective view showing an example of the composition of an article using an optical laminate according to an embodiment of the present invention. Regarding the optical laminates 101 and 102 of the present embodiment, such optical laminates are provided on the display surface of the image display section of an article such as a liquid crystal display panel or an organic EL display panel. Figure 3 shows an example where the optical laminate 101 is provided on the main part 202 of the article 200 surrounded by the frame 201, but it could also be a configuration where the optical laminate 102 is provided. Furthermore, the article is not limited to image display devices. For example, it can be any of the following: goggles with the optical multilayer of this embodiment disposed on their surface; the light-receiving surface of a solar cell; the screen of a smartphone or the display of a personal computer; an information input terminal; a tablet terminal; an AR (augmented reality) device; a VR (virtual reality) device; an electro-optical display panel; a glass table surface; a game console; an aircraft or train operation aid device; a navigation system; an instrument panel; or the surface of an optical sensor. For example, it can also be an article with a curved surface on which the optical multilayer is attached. The article of this embodiment preferably has an optical layer on the surface of the touch panel. Regarding the main part 202 of the article 200, in an article with a display screen, it is typically the display portion corresponding to the screen; in an article without a display screen, it is, for example, the light-transmitting portion through which light passes. Because of this configuration, the article of this embodiment exhibits long-term durability even when subjected to maintenance using alkaline chemicals to remove acidic dirt such as sebum.

[Manufacturing Method of Optical Laminates] The optical laminates 101 and 102 of this embodiment shown in Figures 1 and 2 can be manufactured, for example, by the method described below. In this embodiment, as an example of a manufacturing method for optical laminates 101 and 102, the case of manufacturing optical laminates 101 and 102 using a transparent substrate 11 wound into a roller shape will be explained. First, the transparent substrate 11 wound into a roller shape is unwound. Then, a slurry containing a material that forms a hard coating layer 12 is applied to the transparent substrate 11 using a known method, and then hardened using a known method corresponding to the material that forms the hard coating layer 12. In this way, a hard coating layer 12 is formed (hard coating layer formation step). Subsequently, the transparent substrate 11 on which the hard coating layer 12 is formed is rolled into a roller shape by a known method.

Next, a bonding layer formation step of forming a bonding layer 13 and an optical functional layer formation step of forming an optical functional layer 14 are performed on the hard coating layer 12. The optical functional layer formation step includes a high refractive index layer formation step of forming a high refractive index layer 14a and a low refractive index layer formation step of forming a low refractive index layer 14b in a dry atmosphere. In this embodiment, a dry atmosphere means not a humid atmosphere and means no water vapor flow. Subsequently, a plasma treatment step of plasma treating the low refractive index layer 14b and an antifouling layer formation step of forming an antifouling layer 15 on the surface are performed. In the plasma treatment step, the low refractive index layer 14b is plasma treated in an environment containing a mixture of water vapor and argon. That is, the plasma treatment step is carried out in the presence of _H₂O and Ar. The flow rate ratio of water vapor in the mixture of water vapor and argon introduced in the plasma treatment step can be set to, for example, 2% or more and 100% or less, preferably 10% or more and 90% or less. Here, the flow rate ratio of _H₂O in the mixture in the above-mentioned plasma treatment step means the ratio of the _H₂O flow rate (the value obtained by subtracting the argon flow rate from the total flow rate) (sccm) to the total flow rate (sccm) of the gases flowing as reactive gases in the plasma treatment.

The electrode power density in the plasma treatment step is above 1400 W/ ^m² and below 44200 W/ ^m² , preferably above 4400 W/ ^m² and ^below 18000 W/m², or above 7000 W/ ^m² and below 14000 W/ ^m² .

In the low refractive index layer formation step, a low refractive index layer is formed by sputtering.

In the antifouling layer formation step, the antifouling layer 15 is formed by vapor deposition. The antifouling layer 15 is preferably a compound containing fluorinated organic groups such as alkoxysilyl groups, perfluoropolyether groups, or fluoroalkyl groups. In this embodiment, it is preferable to perform a surface treatment step to treat the surface of the hard coating layer 12 before the optical functional layer formation step, followed by the adhesion layer formation step and the optical functional layer formation step.

As an example of a manufacturing apparatus that can be used in the manufacturing method of the optical laminate of this embodiment, the manufacturing apparatus 20 shown in FIG4 can be cited. The manufacturing apparatus 20 is a roller-to-roll manufacturing apparatus that winds the substrate out of the roller and continuously passes the substrate through the connected devices (pretreatment device 2A, sputtering device 1, pretreatment device 2B, and evaporation device 3 in FIG4) and then winds it, thereby continuously forming multiple layers on the substrate.

When using a roller-to-roll fabrication apparatus to manufacture optical laminates 101 and 102, the conveying speed (linear speed) of the optical laminates 101 and 102 during manufacturing can be appropriately set. For example, the conveying speed is preferably set to 0.5 to 20 m/min, and more preferably to 0.5 to 10 m/min.

The roller winding device 4 includes: a chamber 34 with an internally formed depressurized atmosphere; one or more vacuum pumps 21 (one in Figure 4) that discharge gas from the chamber 34 to form a depressurized atmosphere; and a winding roller 23 and a guide roller 22 disposed within the chamber 34. As shown in Figure 4, the chamber 34 is connected to the chamber 31 of the sputtering apparatus 1. A transparent substrate 11 with a hard coating 12 formed on its surface is wound on the winding roller 23. The winding roller 23 feeds the transparent substrate 11 with the hard coating 12 formed on its surface to the pretreatment apparatus 2A at a specific conveying speed.

<Pretreatment apparatus 2A> The pretreatment apparatus 2A includes: a chamber 32 with an internally formed depressurized atmosphere, a canister roller 26, a plurality of (two in Figure 4) guide rollers 22, and a plasma discharge device 42. As shown in Figure 4, the canister roller 26, the guide rollers 22, and the plasma discharge device 42 are disposed within the chamber 32. As shown in Figure 4, the chamber 32 is connected to the chamber 31 of the sputtering apparatus 1.

The canister roller 26 and guide roller 22 convey the transparent substrate 11 with a hard coating 12, which is transported by the roller unwinding device 4, at a specific conveying speed, and deliver the transparent substrate 11 with the hard coating 12 already treated to the sputtering device 1. As shown in Figure 4, the plasma discharge device 42 is arranged opposite to the outer peripheral surface of the canister roller 26 at specific intervals. The plasma discharge device 42 ionizes the gas by fluorescent discharge. The gas is preferably an inexpensive inert gas that does not affect the optical properties, such as argon, oxygen, nitrogen, helium, etc. Argon is preferred because it has a large mass, is chemically stable, and is readily available. In this embodiment, the plasma discharge device 42 is preferably a luminescent discharge device that uses high-frequency plasma to ionize argon gas.

<Splashing Apparatus> The splashing apparatus 1 includes: a chamber 31 with an internally formed depressurized atmosphere; one or more vacuum pumps 21 (two in FIG. 4) for venting gas from the chamber 31 to form the depressurized atmosphere; a film-forming roller 25; a plurality of guide rollers 22 (two in FIG. 4); and a plurality of film-forming sections 41 (four in the example shown in FIG. 4). As shown in FIG. 4, the film-forming roller 25, the guide rollers 22, and the film-forming sections 41 are disposed within the chamber 31. As shown in FIG. 4, the chamber 31 is connected to the chamber 32 of the pretreatment apparatus 2B.

The film-forming roller 25 and guide roller 22 transport the transparent substrate 11 with a surface-treated hard coating layer 12 from the pretreatment device 2A at a specific transport speed, and supply the transparent substrate 11 with a bonding layer 13 and an optical functional layer 14 formed on the hard coating layer 12 to the pretreatment device 2B. In the sputtering apparatus 1 shown in FIG4, the bonding layer 13 is deposited on the hard coating layer 12 of the transparent substrate 11 moving on the film-forming roller 25 by sputtering, and a high refractive index layer 14a and a low refractive index layer 14b are alternately deposited thereon, thereby forming the optical functional layer 14.

The film-forming sections 41 are arranged facing the outer peripheral surface of the film-forming rollers 25 at specific intervals, and a plurality of them are arranged around the film-forming rollers 25. The number of film-forming sections 41 is determined based on the total number of layers of the close-packed layer 13 and the high-refractive-index layer 14a and low-refractive-index layer 14b forming the optical functional layer 14. When it is difficult to ensure the distance between adjacent film-forming sections 41 because the total number of layers of the close-packed layer 13 and the high-refractive-index layer 14a and low-refractive-index layer 14b forming the optical functional layer 14 is large, a plurality of film-forming rollers 25 may be arranged in the chamber 31, and film-forming sections 41 may be arranged around each film-forming roller 25. When multiple film-forming rollers 25 are provided, guide rollers 22 may also be provided as needed. Multiple chambers 31 equipped with film-forming rollers 25 and film-forming parts 41 may also be connected. Furthermore, in order to easily ensure the distance between adjacent film-forming parts 41, the diameter of the film-forming rollers 25 may be appropriately changed.

Each film-forming section 41 has a specific target (not shown). A voltage is applied to the target using a known structure. In this embodiment, a gas supply section (not shown) that supplies specific reactive gas and carrier gas to the target at a specific flow rate, and a known magnetic field generating source (not shown) that forms a magnetic field on the surface of the target are provided near the target.

The target material, and the type and flow rate of the reactive gas, are appropriately determined based on the composition of the close-bonding layer 13, the high-refractive-index layer 14a, and the low-refractive-index layer 14b formed on the transparent substrate 11 through the film-forming section 41 and the film-forming roller 25. For example, in order to form a low-refractive-index layer 14b containing _SiO2 as the main component, Si is used as the target and _O2 is used as the reactive gas. Similarly, for example, in the case of forming a high-refractive-index layer _14a containing _Nb2O5 as the main component, Nb is used as the target and _O2 is used as the reactive gas.

In this embodiment, from the viewpoint of increasing the film formation speed, magnetron sputtering is preferred. Furthermore, sputtering is not limited to magnetron sputtering; bipolar sputtering using plasma generated by DC glow discharge or high frequency, tripolar sputtering with an additional hot cathode, etc., can also be used.

After the sputtering apparatus 1 forms the bonding layer 13 and the optical functional layer 14, it is equipped with an optical monitor (not shown) as a measuring unit for measuring optical properties. This ensures the quality of the formed bonding layer 13 and optical functional layer 14. When the sputtering apparatus 1 has, for example, two or more chambers, it is preferable to install an optical monitor in each chamber.

An optical monitor (not shown) may, for example, use an optical head capable of scanning in the width direction to measure the optical characteristics of the bonding layer 13 and the optical functional layer 14 formed on the hard coating layer 12 in the width direction. With such an optical monitor, for example, the optical thickness distribution of the bonding layer 13 and the optical functional layer 14 in the width direction can be measured by measuring the peak wavelength of the reflectivity as an optical characteristic and converting it into optical thickness. By using an optical monitor to measure the optical characteristics, the sputtering conditions can be adjusted in real time to form optical laminates 101 and 102 with optimal optical characteristics for the bonding layer 13 and the optical functional layer 14.

<Pretreatment Unit 2B> The pretreatment unit 2B has a chamber 32 with an internally formed depressurized atmosphere, a canister roller 26, a plurality of (two in Figure 4) guide rollers 22, and a plasma discharge device 44. As shown in Figure 4, the canister roller 26, guide rollers 22, and plasma discharge device 44 are disposed within the chamber 36. The pretreatment unit 2B is connected to a gas mixing unit 60 that introduces a mixed gas into the chamber 36. As shown in Figure 4, the chamber 36 is connected to the chamber 33 of the evaporation unit 3.

The can roller 26 and guide roller 22 transport the transparent substrate 11, which is formed with each layer up to the optical functional layer 14, which is conveyed from the sputtering apparatus 1, at a specific conveying speed, and deliver the transparent substrate 11 with the surface treated of the optical functional layer 14 to the vapor deposition apparatus 3. The plasma discharge device 44 can be, for example, the same as the pretreatment device 2A.

As shown in Figure 4, the plasma discharge device 44 is arranged facing the outer peripheral surface of the tank roller 26 at specific intervals. The plasma discharge device 44 ionizes the gas through fluorescent discharge. The gas can be water vapor and argon, and can also be a mixture of oxygen, nitrogen, helium, etc. That is, a mixture of gas containing _H2O and argon can be introduced from the gas mixing unit 60 into the chamber 36 where the plasma discharge device 44 is provided. In this embodiment, the plasma discharge device 44 is preferably a fluorescent discharge device that ionizes argon using high-frequency plasma.

The electrode power density in the plasma treatment step is above 1400 W/ ^m² and below 44200 W/ ^m² , for example, above 4400 W/ ^m² and ^below 18000 W/m², more preferably above 7000 W/ ^m² and below 14000 W/ ^m² .

Figure 5 is a diagram showing an example of the pretreatment device 2B in the manufacturing apparatus shown in Figure 4. In Figure 5, an enlarged view is shown of an example of the simplified gas mixing unit 60 shown in Figure 4. The gas mixing unit 60 includes, for example, an argon gas supply source 61, a water vapor supply source 62 containing water, a heater 63 for heating the water vapor supply source 62, an adjustment chamber 65 connected to the argon gas supply source 61 and the water vapor supply source 62, a vacuum pump 64 for venting the gas from the adjustment chamber 65, and an _H₂O thermometer 66 for measuring the temperature of the water in the water vapor supply source 62. The symbol NB in Figure 5 represents a needle valve, and the symbol MFC represents a mass flow controller.

Argon and water vapor are supplied to the conditioning chamber 65. The argon is supplied by an argon supply source and the flow rate is measured by a mass flow controller (MFC1). The water vapor is contained in a water vapor supply source 62 and evaporated by heating using a heater 63. The mixture of argon and water vapor is supplied from the conditioning chamber 65 to the chamber 36, and its flow rate is adjusted by a mass flow controller (MFC2) located between the conditioning chamber 65 and the chamber 36. Gas in the conditioning chamber 65 that is not supplied to the chamber 36 is discharged by a vacuum pump 64.

Argon gas is known to be introduced into chamber 36 from adjustment chamber 65 with priority over water vapor. The ratio of each component gas in chamber 36 can be measured by a partial pressure vacuum gauge (not shown) installed in chamber 36. It is assumed that the flow rate ratio of water vapor relative to the sum of argon and water vapor supplied to chamber 36 (the sum of the mixed gases) depends on the absolute value of the argon flow rate. By conducting experiments on the dependence of the flow rate ratio of water vapor relative to the sum of the mixed gases on the argon flow rate, the flow rate ratio of water vapor relative to the sum of the mixed gases supplied to chamber 36 can be adjusted to achieve a target value.

The <Evaporation Apparatus> The evaporation apparatus 3 includes a chamber 33 with an internally formed depressurized atmosphere, one or more vacuum pumps 21 (one in Figure 4) for venting gas from the chamber 33 to form the depressurized atmosphere, multiple (four in Figure 4) guide rollers 22, an evaporation source 43, and a heating device 53. As shown in Figure 4, the guide rollers 22 and the evaporation source 43 are disposed within the chamber 33. The chamber 33 is connected to the chamber 35 of the roller take-up device 5.

The vapor deposition source 43 is positioned opposite the transparent substrate 11, which is conveyed substantially horizontally between two adjacent guide rollers 22, and the surface of the optical functional layer 14 has been treated. The vapor deposition source 43 supplies vapor gas containing the material that forms the antifouling layer 15 to the optical functional layer 14. The orientation of the vapor deposition source 43 can be arbitrarily set. The heating device 53 heats the material that forms the antifouling layer 15 to the vapor pressure temperature. The heating device 53 can use methods such as resistance heating, heater heating, induction heating, or electron beam heating. In the resistance heating method, the container housing the antifouling material that forms the antifouling layer 15 is energized and heated as a resistor. In the heating method using a heater, the container is heated by a heater positioned around its outer periphery. In the induction heating method, the container or antifouling material is heated by an externally mounted induction coil through electromagnetic induction.

The vapor deposition apparatus 3 includes a guide plate (not shown) for guiding the vapor deposition material evaporated from the vapor deposition source 43 to a specific position, a film thickness gauge (not shown) for observing the thickness of the antifouling layer 15 formed by vapor deposition, a vacuum gauge (not shown) for measuring the pressure inside the chamber 33, and a power supply device (not shown). The guide plate can be of any shape as long as it can guide the evaporated vapor deposition material to the desired position. If not needed, the guide plate can be omitted. The vacuum gauge can be, for example, an ion meter. The power supply device can be, for example, a high-frequency power supply.

<Roller Winding Device> The roller winding device 5 has a chamber 35 with an internally formed depressurized atmosphere, one or more vacuum pumps 21 (one in Figure 4) to expel gas from the chamber 35 to form a depressurized atmosphere, and a winding roller 24 and a guide roller 22 disposed within the chamber 35. A transparent substrate 11 (optical laminates 101, 102) with layers formed on its surface up to an antifouling layer 15 is wound around the winding roller 24. The winding roller 24 and the guide roller 22 wind the optical laminates 101, 102 at a specific winding speed. A carrier film may also be used if necessary.

The vacuum pump 21 provided with the manufacturing apparatus 20 may be, for example, a dry vacuum pump, an oil swirl pump, a turbine molecular pump, an oil diffusion pump, a cryogenic pump, a sputtering ion pump, a suction pump, etc. The vacuum pump 21 may be appropriately selected or combined for use to create the desired reduced pressure state in each of the chambers 31, 32, 33, 34, and 35.

The vacuum pump 21 only needs to maintain both the chamber 31 of the sputtering apparatus 1 and the chamber 33 of the evaporation apparatus 3 at the desired depressurization state. There are no particular limitations on the location and number of vacuum pumps 21 in the manufacturing apparatus 20. Furthermore, in the manufacturing apparatus 20 shown in Figure 4, the roller winding device 4, the pretreatment device 2A, the sputtering apparatus 1, the pretreatment device 2B, the evaporation apparatus 3, and the roller winding device 5 are connected. Therefore, vacuum pump 21 can be installed in chambers 31, 32, 33, 34, and 35 respectively. If chamber 31 of sputtering device 1 and chamber 33 of evaporation device 3 can be maintained in the desired depressurized state, it can also be installed in only some of the chambers 31, 32, 33, 34, and 35.

Next, the method of using the manufacturing apparatus 20 shown in Figure 4 to perform a high refractive index layer formation step, a low refractive index layer formation step, a plasma treatment step, and an antifouling layer formation step on a substrate, and to manufacture optical laminates 101 and 102 using a roller-to-roll method will be explained.

First, an extrusion roller 23, on which a transparent substrate 11 with a hard coating 12 is formed on its surface, is disposed in the chamber 34 of the roller extrusion device 4. Then, the extrusion roller 23 and the guide roller 22 are rotated, thereby conveying the transparent substrate 11 with the hard coating 12 on its surface to the pretreatment device 2A at a specific conveying speed.

Next, a surface treatment step is performed in chamber 32 of pretreatment device 2A as a pretreatment of the surface to which the bonding layer 13 and optical functional layer 14 are to be formed. In this embodiment, a surface treatment step is performed on the transparent substrate 11 to which the hard coating layer 12 is formed. In the surface treatment step, the can roller 26 and guide roller 22 are rotated, thereby conveying the transparent substrate 11 to which the hard coating layer 12 is formed at a specific conveying speed, and treating the surface of the hard coating layer 12 moving on the can roller 26.

The surface treatment methods for the hard coating layer 12 can include, for example, fluorescent discharge treatment, plasma treatment, ion etching, and alkaline treatment. Among these, fluorescent discharge treatment is preferred because it allows for large-area treatment. Fluorescent discharge treatment can be performed at a treatment intensity of, for example, 0.1 kWh to 10 kWh. By performing fluorescent discharge treatment on the surface of the hard coating layer 12, the surface of the hard coating layer 12 is roughened at the nanoscale, and substances with weak adhesion on the surface of the hard coating layer 12 are removed. As a result, the adhesion between the hard coating layer 12 and the optical functional layer 14 formed on the hard coating layer 12 becomes better.

Next, a bonding layer formation step and an optical functional layer formation step are performed in the chamber 31 of the sputtering apparatus 1. Specifically, the film-forming roller 25 and the guide roller 22 are rotated, thereby conveying the transparent substrate 11 with the hard coating layer 12 formed at a specific conveying speed, and forming a bonding layer 13 and an optical functional layer 14 on the hard coating layer 12 moving on the film-forming roller 25.

Next, a bonding layer formation step and an optical functional layer formation step are performed in the chamber 31 of the sputtering apparatus 1. For example, the bonding layer formation step and the optical functional layer formation step are performed by rotating the film forming roller 25 and the guide roller 22, thereby conveying the transparent substrate 11 with the hard coating layer 12 formed at a specific conveying speed.

In this embodiment, firstly, sputtering is performed on the material of the target disposed on each film-forming section 41, or on the reactive gas supplied from the gas supply section, by varying the type and flow rate, thereby forming a close-fitting layer 13. Then, a high-refractive-index layer 14a and a low-refractive-index layer 14b are alternately deposited on the substrate as high-refractive-index layer formation steps and low-refractive-index layer formation steps. In the high-refractive-index layer formation step, a high-refractive-index layer is formed on the substrate directly or through other layers. Here, in this embodiment, "on the substrate" means on the transparent substrate 11, and does not necessarily involve direct contact with the transparent substrate 11. In this embodiment, a high refractive index layer 14a and a low refractive index layer 14b are formed on a transparent substrate 11 by separating the hard coating layer 12 and the bonding layer 13.

When a SiOx film is used as the bonding layer 13, a silicon target is used to introduce oxygen and argon. When the bonding layer 13, the high-refractive-index layer 14a, and the low-refractive-index layer 14b are continuously deposited by sputtering, the target material can also be formed during the formation of the bonding layer 13, the high-refractive-index layer 14a, and the low-refractive-index layer 14b. Alternatively, for example, a single material can be used as the target, and by varying the oxygen (reactive gas) flow rate during sputtering, layers composed of the target material and layers composed of oxides of the target material can be alternately formed as the bonding layer 13, the high-refractive-index layer 14a, and the low-refractive-index layer 14b.

During the low-refractive-index layer formation step, the process is carried out in chamber 31 under a dry atmosphere without the introduction of _H₂O . If _H₂O is introduced during the low-refractive-index layer formation step, the following risks exist: _SiO₂ within the optical functional layer constituting the low-refractive-index layer may dissolve due to hydrolysis, forming SiOH, causing the characteristics of the optical laminate to deviate from the target characteristics. Furthermore, if the siloxane bonds within the optical functional layer are cleaved to generate hydroxyl groups, the binding energy of _SiO₂ within the optical laminate will decrease. It is believed that hydroxyl groups bonded to Si elements inside the optical functional layer rather than on the surface will not be replaced by silane coupling agents. Therefore, even if the antifouling layer formation step is carried out, hydroxyl groups bonded to Si elements inside the layer that are far from the surface of the low refractive index layer will not help improve the alkali resistance of the optical laminate.

The sputtering pressure during the formation of the close-packed layer 13 and the optical functional layer 14 can be below 2 Pa, preferably below 1 Pa, more preferably below 0.6 Pa, and even more preferably below 0.2 Pa. If the sputtering pressure is below 1 Pa under reduced pressure, the mean free step length of the film-forming molecules increases, and the film will be deposited in a state with higher energy, resulting in a denser film and better film quality.

Subsequently, the transparent substrate 11, on which the bonding layer 13 and the optical functional layer 14 are formed on the hard coating layer 12, is fed to the pretreatment apparatus 2B by the rotation of the film-forming roller 25 and the guide roller 22. An electroplating process is performed in the pretreatment apparatus 2B. In the electroplating process, the low refractive index layer 14b is electroplated in an environment containing a mixture of water vapor and argon. That is, the electroplating process is carried out in an atmosphere containing _H₂O and Ar as reactive gases. Preferably, the mixed gas introduced in the electroplating process contains only water vapor and argon. The atmosphere in chamber 32 of the pretreatment device 2B for the plasma treatment step is preferably an atmosphere containing water vapor and argon.

In the pretreatment apparatus 2B, the low-refractive-index layer 14b, the outermost layer of the optical laminate before the formation of the antifouling layer 15, is pretreated. The pretreatment is performed by plasma treatment of the surface of the low-refractive-index layer 14b in the presence of water vapor and argon. Specifically, a plasma discharge apparatus 44 is used to perform luminescent discharge treatment on one or both of the argon and water vapor by ionization using high-frequency plasma.

As described above, the atmosphere within chamber 36 is an atmosphere containing water vapor and argon, and may also contain oxygen, nitrogen, helium, etc., but preferably only water vapor and argon. The introduction of water vapor and argon into chamber 36 can be performed, for example, by a gas mixing unit 60. In the gas mixing unit 60, the mixed gas, passing through a mass flow controller (MFC2) and a needle valve (NB), is introduced into chamber 36 from the adjusting chamber 65. As described above, the adjusting chamber 65 is supplied with argon from the argon supply source 61 at a flow rate determined by the mass flow controller (MFC1) and water vapor from the water vapor supply source 62. Regarding the mixed gas introduced from the adjustment chamber 65 into the chamber 36, it was confirmed that the introduction of argon gas takes precedence over the introduction of water vapor. Therefore, the flow rate ratio (target %) of water vapor in the mixed gas supplied to the chamber 36 can be calculated based on an approximate curve of the dependence of the flow rate ratio of water vapor relative to the flow rate of argon gas supplied to the chamber 36 in the total amount of argon and water vapor supplied to the chamber 36, which was previously confirmed by experiments.

The flow rate ratio (target %) of water vapor in the mixed gas introduced into chamber 36 can be set to, for example, 2% or more and 100% or less, preferably 10% or more and 90% or less. By performing the plasma treatment step under the above conditions, the surface of the low-refractive-index layer 14b in the optical laminate becomes hydrophilic. During the antifouling layer formation step described below, the fluorine-based organic compounds constituting the antifouling layer readily combine with the hydroxyl groups generated in the low-refractive-index layer 14b. Therefore, the amount of fluorine-based organic compounds constituting the antifouling layer on the outermost surface of the optical laminates 101 and 102 can be increased. If the water content ratio of the atmosphere in chamber 36 is excessive, a portion of the hydroxyl groups will not combine with the fluorine-based organic compounds, and a portion of the hydroxyl groups will remain on the surface. It is believed that when optical laminates are exposed to alkaline solutions or atmospheres, the alkali metals are replaced by hydrogen on the surface, leading to degradation caused by the alkaline solution or atmosphere. Due to this mechanism, it is believed that long-term alkali resistance becomes particularly high when the water content ratio in the atmosphere of the plasma treatment step is below a certain value.

Furthermore, in the pretreatment apparatus 2B shown in Figures 4 and 5, the argon and water vapor in the mixed gas are temporarily stored in the adjustment chamber 65 before being supplied to the chamber 36. Therefore, the ratio of water vapor in the atmosphere of the chamber 36 to the sum of argon and water vapor may not be consistent with the flow rate ratio of water vapor in the mixed gas. The ratio (actual ratio) of water vapor in the atmosphere of the chamber 36 to the sum of water vapor and argon is, for example, more than 0.5% and less than 70%, preferably more than 6% and less than 65%, and more preferably more than 6.5% and less than 50%.

The total pressure in the chamber during the plasma treatment step is preferably set to be above 0.008 Pa and below 0.02 Pa.

Subsequently, the transparent substrate 11 with the surface treated of the optical functional layer 14 is conveyed to the vapor deposition apparatus 3 by the rotation of the tank roller 26 and the guide roller 22. Next, an antifouling layer formation step is performed in the chamber 33 of the vapor deposition apparatus 3. In this embodiment, an antifouling layer formation step is performed on the laminate formed by plasma treatment of the surface of the outermost low refractive index layer 14b in the plasma treatment step. In the antifouling layer formation step, the guide roller 22 is rotated, thereby conveying the transparent substrate 11 with the surface treated of the optical functional layer 14 at a specific conveying speed, while the vapor deposition source 43 is deposited on the surface of the optical functional layer 14.

In this embodiment, for example, the antifouling material containing a fluorinated organic compound, which becomes the antifouling layer 15, is heated to a vapor pressure temperature by a heating device 53. Under reduced pressure, the obtained vaporized gas is supplied from the vapor deposition source 43, causing it to adhere to the surface-treated optical functional layer 14, and the antifouling layer 15 is formed by vacuum vapor deposition. Regarding the antifouling material, compounds containing fluorinated modified organic groups and reactive silyl groups (e.g., alkoxysilanes) are preferably used as the fluorinated organic compound. Commercially available examples include OPTOOL DSX (manufactured by Daikin Co., Ltd.) and KY-100 Series (manufactured by Shin-Etsu Chemical Co., Ltd.).

The pressure during vacuum evaporation of the antifouling layer 15 is preferably 0.05 Pa or less, more preferably 0.01 Pa or less, and even more preferably 0.001 Pa or less. If the pressure during vacuum evaporation is reduced to 0.05 Pa or less, the mean free step of the film-forming molecules is longer, the evaporation energy is higher, and thus a denser and better antifouling layer 15 is obtained.

Optical laminates 101 and 102, as shown in Figures 1 and 2, can be manufactured using the method described above.

The optical laminate of this embodiment can also be an optical laminate without the hard coating layer 12 and the bonding layer 13. When forming such an optical laminate, a substrate without the hard coating layer 12, i.e., a substrate composed of a transparent substrate 11, can also be used, thus omitting the surface treatment step and the bonding layer formation step. Furthermore, in this embodiment, the term "above the transparent substrate 11" is sufficient; the substrate can be configured not to contact the transparent substrate 11.

According to the above-described embodiment, the plasma treatment step is performed under conditions of introducing a mixture of argon and water vapor. In addition to the hydroxyl groups generated by the argon plasma treatment and bonded to the Si bonds on the outermost surface of the optical functional layer 14 (a few nm away from the surface), hydroxyl groups are also generated by the hydrolysis of SiO bonds near the outermost surface of the optical functional layer 14. This allows for easy chemical reaction with the reactive silyl fluorinated organic compounds constituting the antifouling layer 15. That is, the amount of fluorinated organic compounds in the antifouling layer 15 formed on the optical functional layer 14 can be increased, and even if alkaline solutions adhere to the surfaces of the optical layers 101 and 102, the exposure of SiO bonds in the optical functional layer 14 can be reduced. Here, by forming a low refractive index layer 14b in a dry atmosphere, the growth and hydrolysis of hydroxyl groups inside the low refractive index layer 14b that do not contribute to the bonding with the antifouling layer 15 can be suppressed, thereby suppressing the deterioration of optical properties.

Furthermore, the glow discharge treatment in the plasma processing step of the low refractive index layer 14b can improve the surface energy of the optical functional layer 14, making it easier to attach the antifouling layer 15. Through glow discharge, hydrophilicity occurs, and the water contact angle decreases, reducing the amount of fluorine-based organic compounds that cannot bond to the substrate and thus become free. According to this embodiment, an optical laminate with excellent long-term alkali resistance can be provided in this way.

The embodiments of this invention have been described in detail above. However, this invention is not limited to the above embodiments, and various omissions, substitutions, changes/modifications may be made within the scope of the spirit of this invention as recorded in the patent application. Such embodiments or changes thereof are included in the scope or spirit of the invention, and likewise, they are also included in the scope of the invention as recorded in the patent application and its equivalents.

The upper and/or lower limits of the numerical ranges described in this specification can be arbitrarily combined to define a better range. For example, the upper and lower limits of the numerical ranges can be arbitrarily combined to define a better range, the upper limits of the numerical ranges can be arbitrarily combined with each other to define a better range, and the lower limits of the numerical ranges can be arbitrarily combined with each other to define a better range.

It should be understood throughout this invention that, unless otherwise stated, the singular form of a statement also includes the concept of its plural form. Therefore, it should be understood that, unless otherwise stated, the singular articles (e.g., "a," "an," "the," etc. in the case of English) also include the concept of their plural forms.

[Examples] Hereinafter, embodiments of the present invention will be described. Furthermore, the optical laminates produced in the following embodiments and comparative examples are examples of functions as antireflective films, and the purpose of the present invention is not limited to them.

(Example 1-1) First, a resin film containing silica microparticles and formed on a 4 μm thick TAC is prepared as a transparent substrate.

Secondly, using a roller-to-roll method, a close-fitting layer is formed on a transparent substrate with a hard coating, and then high-refractive-index and low-refractive-index layers are alternately formed as optical functional layers. After forming the uppermost low-refractive-index layer in the optical functional layers, a plasma treatment step is performed, followed by the formation of an antifouling layer, thereby producing an optical laminate (anti-reflective film).

The manufacturing apparatus used is the manufacturing apparatus 20 shown in Figure 4. The linear velocity is set to 2 m/min. The total pressure during the formation of the optical laminate is set to 1 Pa or less.

For the hard coating layer 12, a light discharge treatment is performed with a processing speed of 400 W·min/m ^2. Subsequently, on the hard coating layer 12 after light discharge treatment, a 5 nm thick SiOx-containing bonding layer 13 is sputtered into a chamber with a pressure of less than 1.0 Pa. On the bonding layer, an optical functional layer 14 (laminated layer) is formed, consisting of a 15 nm thick Nb ₂ O ₅ film (high refractive index layer), a 38 nm thick SiO ₂ film (low refractive index layer), a 30 nm thick Nb ₂ O ₅ film (high refractive index layer), and a 102 nm thick SiO ₂ film (low refractive index layer). The high-refractive-index layer and the low-refractive-index layer were formed in a dry atmosphere without the introduction of _H2O .

Next, the aforementioned low-refractive-index layer is subjected to plasma treatment in the presence of moisture and argon. The plasma treatment of the low-refractive-index layer surface is carried out in an atmosphere of _H₂O and Ar while water vapor and argon are introduced into the chamber. The total flow rate of water vapor and argon introduced from the adjustment chamber 65 into the chamber 36 is set to 500 sccm, and the argon supply from the argon supply source 61 to the adjustment chamber 65 is set to 500 sccm. Thus, in Embodiment 1-1, the flow rate ratio of water vapor in the mixture of water vapor and argon introduced into the chamber 36 is set to 10%, and the flow rate ratio of argon is set to 90%. Sometimes the flow rate ratio of water vapor in the mixture of water vapor and argon introduced into chamber 36 is expressed as the target _H₂O %. That is, in Embodiment 1-1, the target _H₂O % is 10%. The target _H₂O % is based on an approximate curve obtained beforehand that correlates with the average _H₂O ratio. The flow rate ratio of argon is determined based on this approximate curve and the target _H₂O %. Furthermore, the ratios of _H₂O , Ar, _H₂ , and _O₂ in the atmosphere within chamber 36 are measured using a partial pressure vacuum gauge (manufactured by ULVAC Co., Ltd., model: CGM051). The ratio of _H₂O in the atmosphere within chamber 36 is 9.4%. Sometimes the ratio of _H₂O in the atmosphere within chamber 36 is expressed as _H₂O .

The approximate curve relating to the average _H₂O ratio was obtained in advance using the following method. First, using the apparatus used in Example 1-1, a specific amount of argon and water vapor was supplied to the chamber under the same environment as in Example 1-1. At this time, the flow rate of argon was measured using a mass flow meter installed between the argon supply source and the chamber, and the ratio of each component gas in the chamber was measured using a partial pressure vacuum gauge installed in the chamber. The ratio of water vapor to the total amount of the mixed gas supplied to the chamber was measured when the argon was set to 10, 20, 50, 100, 150, 175, 200, 250, 300, 400, and 500 [SCCM], and the results were plotted as a curve. Then, using the plotted data, an approximate curve is generated regarding the dependence of the flow rate ratio of water vapor in the mixture relative to the argon flow rate using the nonlinear least squares method. The argon flow rate for obtaining a specific water vapor can be determined from this approximate curve.

The electrode power density for the photoluminescence discharge treatment when performing photoluminescence discharge treatment on the outermost surface of the low refractive index layer is set to 4421 (W/m ² ).

Next, on the optical functional layer, an antifouling layer 15 with an optical thickness of 4 nm is formed by evaporation at a pressure below 0.01 Pa and a evaporation temperature of 230°C in the evaporation chamber. This antifouling layer 15 contains an organic compound containing fluorine, namely an alkoxysilane compound with a perfluoropolyether group (KY-1901, manufactured by Shin-Etsu Chemical Industry Co., Ltd.). Subsequently, it is rolled into a roll to obtain the optical laminate (antireflective film) of Example 1.

(1) Abrasion resistance test using waste cloth (non-woven wiping cloth) In addition to using waste cloth (non-woven wiping cloth) (Bemcot Lint-Free CT-8, manufactured by Asahi Chemical Processing Co., Ltd.) as the friction element, an abrasion resistance test was conducted. The test settings were: load 250 g/ ^cm² , stroke 25 mm, speed 50 mm/s. The number of horizontal reciprocating motions of the friction element was set to 4000.

The water contact angle of the test piece after friction was measured, and the water contact angle of the test piece before friction and after 4000 horizontal reciprocating motions was calculated. The test was conducted within 30 minutes after friction.

(2) Alkali resistance test: A black acrylic resin plate was attached to the back of the optical laminate using transparent tape to eliminate back reflection. The luminance L ^* , chromaticity a ^* , and b ^* of the untreated optical laminate were measured using the SCI method in the CIE1976 (L ^* a ^* b ^* ) color space as optical characteristics. Optical measurements were performed using an integrating sphere spectrophotometer (SP-64: manufactured by X-rite Co., Ltd.). The settings were set to a D65 light source and a field of view of 10°.

Furthermore, a 0.1 mol/L sodium hydroxide aqueous solution was prepared. The optical laminate was housed in a cylindrical component with an inner diameter of 38 mm. The reagent was dropped into the cylindrical component, and the opening on the upper surface was covered with a glass plate. Then, the liquid temperature was maintained at 55°C and allowed to stand for 4 hours. Each sample was then washed with distilled water to obtain the treated sample. The optical properties of the optical laminate after standing for 4 hours were evaluated using the same method as the untreated sample. The ΔE value of the optical laminate after 4 hours of treatment relative to the untreated optical laminate was measured as expressed by the following formula (1). ΔE ^* _ab ＝{(L ^* ₂ －L ^* ₁ ) ² ＋(a ^* ₂ －a ^* ₁ ) ² ＋(b ^* ₂ －b ^* ₁ ) ² } ^1/2・・・(1)(where, L ^* ₁ : brightness before the NaOH aqueous solution is added, L ^* ₂ : brightness after a specific time has elapsed since the NaOH aqueous solution was added, a ^* ₁ : chromaticity before the NaOH aqueous solution was added, a ^* ₂ : chromaticity after a specific time has elapsed since the NaOH aqueous solution was added, b ^* ₁ : chromaticity before the NaOH aqueous solution was added, b ^* ₂ : chromaticity after a specific time has elapsed since the NaOH aqueous solution was added)

(3) Fluorine content determination test: The fluorine content (cps: count value per unit time) of the optical laminate (sample) is determined (fluorine content before cleaning (fluorine content in the initial state)).

The fluorine content was determined using an X-ray photoelectron spectrophotometer (Electron Spectroscopy for Chemical Analysis, ESCA) (PHI5000 VersaProbe III, manufactured by ULVAC-PHI Corporation) and X-ray fluorescence analysis (XRF) (EDX-8000, manufactured by Shimadzu Corporation). The fluorine value (cps) obtained by X-ray photoelectron spectrophotometer and XRF analysis was the average value calculated from the results obtained by measurements with an initial state of n=3.

(4) _SiO2 Binding Energy Measurement Test: The binding energy of _SiO2 on the optical laminate was measured from the antifouling layer side using X-ray photoelectron analysis (ESCA) as described in (3) under the following conditions. In ESCA, the binding energy of _SiO2 at a distance of several nm from the surface of the optical laminate can be measured. For reference, the binding energy of elemental silicon is 99.2 eV, the binding energy of silicone is 102.4 eV, and the binding energy of _SiO2 is 103.6 eV. That is, when the binding energy is lower than 103.6 eV, it can be seen that the antifouling layer is thicker or formed with a high density. In addition, a wide scan was also performed to confirm the metal elements contained in the optical laminate. Regarding metal elements, metals other than those constituting the optical laminate are also included in the detection scope. The inclusion of metal elements other than those in the metal oxides used to constitute the optical laminate (metal elements other than Nb and Si in Example 1-1) is confirmed. ESCA Measurement Conditions: Measurement: Narrow scan, wide scan; X-ray source: Single Al; X-ray gun: 200 μm, ϕ 50 W, 15 V; Dwell time (single step time): 20 ms; Step size (measurement interval): 0.05 eV; Scans (cumulative): 10; Through energy: 55 eV

(Examples 1-2 to 1-5) Adjust the amount of argon gas supplied from argon gas supply source 61 to adjustment chamber 65 in the plasma treatment step of the low refractive index layer surface to the target _H2O percentage as shown in Table 1. Otherwise, the optical laminate is fabricated and evaluated in the same manner as in Example 1-1.

(Examples 2-1 to 2-3) Examples 2-1 to 2-5 set the electrode power density during the glow discharge treatment in the plasma treatment step of the low refractive index layer surface to 7516 (W/ ^m² ), and adjusted the amount of argon gas supplied from the argon gas supply source 61 to the adjustment chamber 65 to the target _H₂O percentage shown in Table 1. Otherwise, the optical laminate was fabricated and evaluated in the same manner as in Example 1-1. The _H₂O percentage during the plasma treatment step is shown in Table 3.

(Examples 3-1 to 3-5) Examples 3-1 to 3-5 set the electrode power density during the glow discharge treatment in the plasma treatment step of the low refractive index layer surface to 8842 (W/ ^m² ), and adjusted the amount of argon gas supplied from the argon gas supply source 61 to the adjustment chamber 65 to the target _H₂O percentage shown in Table 1. Otherwise, the optical laminate was fabricated and evaluated in the same manner as in Example 1-1. The _H₂O percentage during the plasma treatment step is shown in Table 3.

(Examples 4-1 to 4-5) Examples 4-1 to 4-5 set the electrode power density during the glow discharge treatment in the plasma treatment step of the low refractive index layer surface to 13263 (W/ ^m² ), and adjusted the amount of argon gas supplied from the argon gas supply source 61 to the adjustment chamber 65 to the target _H₂O percentage shown in Table 1. Otherwise, the optical laminate was fabricated and evaluated in the same manner as in Example 1-1. The _H₂O percentage during the plasma treatment step is shown in Table 3.

(Examples 5-1 to 5-3) Examples 5-1 to 5-3 set the electrode power density during the glow discharge treatment in the plasma treatment step of the low refractive index layer surface to 17684 (W/ ^m² ), and adjusted the amount of argon gas supplied from the argon gas supply source 61 to the adjustment chamber 65 to the target _H₂O percentage shown in Table 1. Otherwise, the optical laminate was fabricated and evaluated in the same manner as in Example 1-1. The _H₂O percentage during the plasma treatment step is shown in Table 3.

(Comparative Example 1) During the glow discharge process in the surface treatment of the low refractive index layer, water vapor is not introduced into chamber 36 as a reactive gas; instead, argon gas is allowed to flow. Otherwise, the optical laminate is fabricated in the same manner as in Example 1-1. The _H₂O % during the plasma treatment step is shown in Table 4.

(Comparative Example 2) During the glow discharge process in the surface treatment of the low refractive index layer, water vapor is not introduced into chamber 36 as a reactive gas; instead, argon gas is allowed to flow. Otherwise, the optical laminate is fabricated in the same manner as in Example 2-1. The _H₂O % during the plasma treatment step is shown in Table 4.

(Comparative Example 3) During the optical discharge process in the surface treatment of the low refractive index layer, the electrode power density was set to 17684 W/ ^m² . Water vapor was not introduced into the chamber 36 as a reactive gas; instead, argon gas was allowed to flow. Otherwise, the optical laminate was fabricated in the same manner as in Example 1-1. The _H₂O % during the plasma treatment step is shown in Table 4.

(Comparative Examples 4-1 to 4-4) During the glow discharge treatment in the surface treatment of the low refractive index layer, the electrode power density was set to 1326 W/ ^m² , and the amount of argon gas supplied from the argon gas supply source 61 to the adjustment chamber 65 was adjusted to the target _H₂O percentage as shown in Table 1. Otherwise, the optical laminate was fabricated in the same manner as in Example 1-1. The _H₂O percentage during the plasma treatment step is shown in Table 4.

As described above, the characteristics of the optical laminates produced in the embodiments and comparative examples were evaluated. The characteristic measurement results of the optical laminates of Embodiments 1-1 to 5-3 are summarized in Table 1, and the characteristic measurement results of the optical laminates of Comparative Examples 1 to 4-4 are summarized in Table 2. In Tables 1 and 2, in the column "Detection of metal elements such as Al using ESCA", if the inclusion of metal elements other than the metals of the metal oxides used to constitute the optical laminate is detected by ESCA, it is indicated by "○", and if it is not detected, it is indicated by "-". Furthermore, regarding the ratio of each gas in the atmosphere within chamber 36 and the total pressure (TP value) within chamber 36 measured using a partial pressure vacuum gauge, the results of Examples 1-1 to 5-3 are summarized in Table 3, and the results of Comparative Examples 1 to 4-4 are summarized in Table 4.

[Table 1] Electrode power density during plasma treatment [W/ ^m² ] _H₂O target percentage during plasma treatment steps During the plasma treatment step, _H2O % Full pressure [Pa] during plasma treatment. Abrasion resistance test contact angle [°] Alkali resistance (∆E value) XRF ESCA _SiO₂ binding energy [eV] Detection of metal elements such as Al using ESCA 0 round trips 400 round trips 4 h Implementation Example 1-1 4421 10% 9.4% 0.040 118.0 106.2 6.4 0.058 103.23 - Implementation Examples 1-2 4421 25% 17.5% 0.044 118.9 106.8 3.4 0.056 103.25 - Implementation Examples 1-3 4421 50% 29.4% 0.015 118.0 107.8 3.7 0.055 103.25 - Implementation Examples 1-4 4421 75% 40.5% 0.008 119.8 103.5 2.5 0.058 103.21 - Implementation Examples 1-5 4421 90% 46.9% 0.007 119.2 107.2 5.3 0.059 103.23 - Implementation Example 2-1 7516 10% 8.3% 0.042 119.0 106.4 2.4 0.056 103.17 - Implementation Example 2-2 7516 25% 15.0% 0.044 118.6 106.5 2.8 0.059 103.21 - Implementation Examples 2-3 7516 50% 26.8% 0.016 119.3 111.8 3.4 0.057 103.18 - Implementation Examples 2-4 7516 75% 34.5% 0.009 119.4 109.2 2.4 0.056 103.13 - Implementation Examples 2-5 7516 90% 38.6% 0.008 118.5 105.9 2.0 0.057 103.21 - Implementation Example 3-1 8842 10% 7.8% 0.043 119.6 109.6 1.9 0.058 103.13 - Implementation Example 3-2 8842 25% 14.9% 0.044 118.3 106.6 2.5 0.058 103.17 - Implementation Example 3-3 8842 50% 24.9% 0.016 117.5 106.3 3.2 0.055 103.14 - Implementation Examples 3-4 8842 75% 32.7% 0.010 119.2 106.1 2.7 0.055 103.19 - Implementation Examples 3-5 8842 90% 36.4% 0.009 118.4 107.2 1.7 0.057 103.23 - Implementation Example 4-1 13263 10% 6.8% 0.044 118.6 107.2 2.4 0.056 103.06 - Implementation Example 4-2 13263 25% 13.4% 0.046 118.5 108.2 1.9 0.057 103.07 - Implementation Example 4-3 13263 50% 22.2% 0.017 119.3 107.6 1.4 0.056 103.14 - Implementation Example 4-4 13263 75% 27.8% 0.011 118.3 107.1 1.7 0.056 103.13 - Implementation Examples 4-5 13263 90% 31.2% 0.010 117.9 104.6 3.1 0.060 103.04 - Implementation Example 5-1 17684 10% 6.2% 0.043 119.0 106.4 1.9 0.059 103.09 - Implementation Example 5-2 17684 50% 20.1% 0.018 118.3 107.6 2.7 0.054 103.01 - Implementation Example 5-3 17684 90% 27.0% 0.011 117.7 106.4 1.9 0.058 103.05 -

[Table 2] Electrode power density during plasma treatment [W/ ^m² ] _H₂O target percentage during plasma treatment steps During the plasma treatment step, _H2O % Full pressure [Pa] during plasma treatment. Abrasion resistance test contact angle [°] Alkali resistance (∆E value) XRF ESCA _SiO₂ binding energy [eV] Detection of metal elements such as Al using ESCA 0 round trips 400 round trips 4 h Comparative example 1 1326 0 0.5% 0.147 117.7 108.3 14.6 0.054 103.20 - Comparative example 2 7516 0 0.4% 0.148 118.4 107.0 22.0 0.054 102.99 ○ Comparative example 3 17684 0 0.4% 0.149 118.9 108.3 18.9 0.058 102.98 ○ Comparative example 4-1 1326 10% 10.7% 0.038 117.0 104.4 18.5 0.058 103.24 - Comparative example 4-2 1326 25% 22.3% 0.042 118.7 104.1 25.4 0.055 103.19 - Comparative example 4-3 1326 50% 39.9% 0.013 119.0 112.6 18.4 0.056 103.20 - Comparative example 4-4 1326 75% 55.2% 0.007 117.1 109.6 19.0 0.053 103.21 -

[Table 3] Actual _H₂O ratio (%) Ar actual ratio (%) _H2 actual ratio (%) O ₂ Actual Ratio (%) TP value (Pa) Implementation Example 1-1 9.4% 1.4% 23.0% 65.3% 0.040 Implementation Examples 1-2 17.5% 1.8% 29.7% 49.4% 0.044 Implementation Examples 1-3 29.4% 2.8% 31.3% 28.9% 0.015 Implementation Examples 1-4 40.5% 3.9% 37.5% 13.1% 0.008 Implementation Examples 1-5 46.9% 4.6% 40.5% 4.3% 0.007 Implementation Example 2-1 8.3% 1.7% 28.6% 59.6% 0.042 Implementation Example 2-2 15.0% 2.1% 36.0% 44.8% 0.044 Implementation Examples 2-3 26.8% 3.5% 40.6% 25.1% 0.016 Implementation Examples 2-4 34.5% 4.4% 44.7% 10.8% 0.009 Implementation Examples 2-5 38.6% 5.2% 47.7% 3.7% 0.008 Implementation Example 3-1 7.8% 1.8% 30.1% 57.8% 0.043 Implementation Example 3-2 14.9% 2.3% 38.1% 42.1% 0.044 Implementation Example 3-3 24.9% 3.6% 42.3% 24.5% 0.016 Implementation Examples 3-4 32.7% 4.8% 47.6% 10.0% 0.010 Implementation Examples 3-5 36.4% 5.4% 50.0% 3.4% 0.009 Implementation Example 4-1 6.8% 2.0% 34.8% 53.3% 0.044 Implementation Example 4-2 13.4% 2.6% 44.0% 38.7% 0.046 Implementation Example 4-3 22.2% 3.9% 48.1% 21.2% 0.017 Implementation Example 4-4 27.8% 5.2% 52.3% 8.4% 0.011 Implementation Examples 4-5 31.2% 5.7% 55.6% 2.7% 0.010 Implementation Example 5-1 6.2% 2.2% 38.0% 49.5% 0.043 Implementation Example 5-2 20.1% 4.2% 53.3% 18.4% 0.018 Implementation Example 5-3 27.0% 5.9% 58.7% 2.5% 0.011

[Table 4] Actual _H₂O ratio (%) Ar actual ratio (%) _H2 actual ratio (%) O ₂ Actual Ratio (%) TP value (Pa) Comparative example 1 0.5% 0.0% 0.3% 99.3% 0.147 Comparative example 2 0.4% 0.0% 0.7% 98.6% 0.148 Comparative example 3 0.4% 0.0% 1.4% 97.3% 0.149 Comparative example 4-1 10.7% 0.7% 12.0% 75.5% 0.038 Comparative example 4-2 22.3% 1.0% 16.9% 58.7% 0.042 Comparative example 4-3 39.9% 1.6% 18.2% 37.1% 0.013 Comparative example 4-4 55.2% 2.3% 21.6% 17.4% 0.007

By comparing Examples 1-1 to 5-3 with Comparative Examples 1 to 4-4, it can be confirmed that in the plasma treatment step, using _H₂O flow as a reactive gas exhibits superior alkali resistance compared to those without _H₂O as a reactive gas. This demonstrates that the presence of _H₂O gas during plasma treatment of the low refractive index layer results in higher alkali resistance after the formation of the antifouling layer.

However, when Comparative Examples 4-1 to 4-5 are compared with Examples 1-1 to 5-3, even when the target _H₂O % is set to the same level and the _H₂O % range is set in the same range in both examples and comparisons, the alkali resistance of Comparative Examples 4-1 to 4-5 is still lower. This result shows that even with the introduction of _H₂O gas, improving alkali resistance requires a certain level of electrode power density during the plasma treatment steps.

That is, it can be seen that by changing the conditions of the plasma treatment steps, the amount of fluorine-based organic compounds forming the antifouling layer on the low refractive index layer increases. It is believed that because the amount of fluorine-based organic compounds constituting the antifouling layer increases, the area of _SiO2 constituting the low refractive index layer that comes into contact with water decreases, inhibiting the hydrolysis of siloxane bonds and the replacement of the H in the hydroxyl group with an alkali metal, thus obtaining the alkali resistance described above.

1: Splash coating apparatus 2A: Pretreatment apparatus 2B: Pretreatment apparatus 3: Evaporation apparatus 4: Apparatus 11: Transparent substrate 12: Hard coating layer 13: Adhesive layer 14: Optical functional layer 14a: High refractive index layer 14b: Low refractive index layer 15: Antifouling layer 20: Manufacturing apparatus 21: Vacuum pump 22: Guide roller 23: Roller 24: Take-up roller 25: Film-forming roller 26: Tank roller 31: Chamber 32: Chamber 33: Chamber 34: Chamber 35: Chamber 36: Chamber 41: Film-forming section 42: Plasma discharge device 43: Evaporation source 60: Mixed gas adjustment unit 61: Argon gas supply source 62: Water vapor supply source 63: Heater 64: Vacuum pump 65: Adjustment chamber 66: _H₂O thermometer 101, 102: Optical laminate 200: Item 201: Frame 202: Main part MFC: Mass flow controller NB: Needle valve

Figure 1 is a cross-sectional view showing an example of the optical laminate configuration according to one embodiment of the present invention. Figure 2 is a cross-sectional view showing another example of the optical laminate of Figure 1. Figure 3 is a perspective view showing an example of the article configuration using the optical laminate of one embodiment of the present invention. Figure 4 is a schematic diagram showing an example of a manufacturing apparatus for a manufacturing method of the optical laminate of one embodiment of the present invention. Figure 5 is a diagram showing an example of the pretreatment apparatus 2B in the manufacturing apparatus shown in Figure 4.

11: Transparent substrate

12: Hard Coating

13: Adhesive layer

14: Optical functional layer

14a: High refractive index layer

14b: Low refractive index layer

15: Anti-fouling layer

101: Optical Laminators

Claims (11)

A method for manufacturing an optical laminate, the optical laminate comprising a substrate, a high refractive index layer disposed on the substrate directly or interposed of other layers, and SiO2 formed on the high refractive index layer. The optical laminate manufacturing method comprises: _a low refractive index layer as the main component and an antifouling layer formed on the low refractive index layer; a low refractive index layer forming step of forming a high refractive index layer; a plasma treatment step of plasma treatment of the low refractive index layer; and an antifouling layer forming step of forming an antifouling layer on the surface; wherein, in the plasma treatment step, the low refractive index layer is plasma treated in an environment in which a mixture of water vapor and argon is introduced, and the low refractive index layer is plasma treated at an electrode power density of 4400 W/ ^m² or more and 18000 W/ ^m² or less. As in the method for manufacturing the optical laminate of claim 1, in the above-mentioned plasma processing step, the flow rate ratio of water vapor in the mixed gas of water vapor and argon is set to be more than 10% and less than 90%. The manufacturing method of the optical multilayer as claimed in claim 1 or 2, wherein the electrode power density in the plasma processing step is 7000 W/ ^m² or more and 14000 W/ ^m² or less. The method for manufacturing an optical laminate as described in claim 1 or 2, wherein the low refractive index layer is formed by sputtering in the step of forming the low refractive index layer. The method for manufacturing an optical laminate as claimed in claim 1 or 2, wherein in the step of forming the antifouling layer, the antifouling layer is formed by vapor deposition, and the antifouling layer comprises a compound having alkoxysilyl groups and fluorine-modified organic groups. The method for manufacturing an optical laminate as claimed in claim 1, wherein in the plasma processing step, the ratio of _H2O in the atmosphere of the space where the low refractive index layer is plasma processed is 6.5% or more and 50% or less. An optical laminate comprising a substrate, a high refractive index layer disposed on the substrate directly or interposed of other layers, a low refractive index layer formed on the high refractive index layer and containing _SiO2 as the main component, and an antifouling layer formed on the low refractive index layer, wherein after dropping a 0.1 (mol/L) NaOH aqueous solution and standing at 55°C for 4 hours, the ΔE value expressed by the following formula (1) is 8 or less, ΔE ^* _ab ＝{(L ^* ₂ －L ^* ₁ ) ² ＋(a ^* ₂ －a ^* ₁ ) ² ＋(b ^* ₂ －b ^* ₁ ) ² } ^1/2・・・(1) (where, L ^* ₁ : brightness before dropping the NaOH aqueous solution, L ^* ₂ : Brightness after a specific time since the NaOH aqueous solution was added, a ^* ₁ : Color before the NaOH aqueous solution was added, a ^* ₂ : Color after a specific time since the NaOH aqueous solution was added, b ^* ₁ : Color before the NaOH aqueous solution was added, b ^* ₂ : Color after a specific time since the NaOH aqueous solution was added). For example, in the optical laminate of claim 7, the binding energy of _SiO2 measured by X-ray photoelectron analysis (ESCA) from the antifouling layer side is below 103.25 eV. As in claim 7, the optical laminate contains an oxide of a first metal element in the high refractive index layer and an oxide of a second metal element in the low refractive index layer, and the metal elements detected by measurement using ESCA are only the first metal element and the second metal element. The optical laminate of claim 7 further comprises a bonding layer between the substrate and the high refractive index layer, wherein the high refractive index layer comprises an oxide of a first metal, the low refractive index layer comprises an oxide of a second metal, the bonding layer comprises an oxide of a third metal, and the metal elements detected by measurement using ESCA are only the first metal element, the second metal element, and the third metal element. An article having an optical layer as described in any of requests 7 to 10.