JP7213323B2 - optical laminate, article - Google Patents

Description

TECHNICAL FIELD The present invention relates to an optical layered body and an article having the same.

2. Description of the Related Art Conventionally, an optical multilayer film in which a plurality of transparent materials having a thickness approximately equal to the wavelength of light is laminated has been applied in various fields. In particular, antireflection coatings that reduce the reflection of light on the surface by shifting the phase of reflection, and wavelength selective coatings that transmit or reflect only specific wavelengths have been applied to camera lenses and window glass. In addition, the display contents of televisions and the like sometimes become difficult to see due to the reflection of external light, and the visibility can be improved by attaching an antireflection film.

With the progress of electronic technology in recent years, displays are increasingly being installed in portable devices, and high-definition displays are now being installed in notebook computers, smartphones, and the like. Furthermore, in recent years, the use of IT in automobiles has progressed, and a large number of displays for displaying various information have come to be installed in addition to conventional speedometers.
For such applications, weight reduction is desired from the viewpoint of portability, and it is desired to form an antireflection film on a film instead of the conventional glass. In addition, even if the display is made of glass, in the unlikely event that it breaks, a film is attached to the surface to prevent scattering, so an antireflection film is often attached.

As a method for realizing an optical multilayer film, there are a wet method in which materials with different refractive indices are applied in the atmosphere, and a dry method in which a film is formed by blowing a film-forming material in a vacuum. Although the wet method is convenient, the materials that can be applied are limited, and it is difficult to form a layer having the optical properties required for an optical multilayer film, and it is also difficult to laminate a large number of layers. On the other hand, the method of forming films in a vacuum can laminate a wide variety of materials many times. There are several dry film deposition methods, but the sputtering method, which uses plasma in a vacuum, has various advantages such as the ability to deposit materials with high melting points and the ability to ensure film thickness uniformity. Widely used for thin film deposition.
In addition, since a uniform film thickness distribution can be achieved for a long time by using the sputtering method, a roll-to-roll sputtering device combining this with a film transport device can form a large area film at once. It has industrial advantages.

However, when an optical multilayer film is formed on a film, the substrate film is made of resin (polymer), whereas the optical thin film forming the optical multilayer film is often made mainly of oxide. Adhesion between the material and the thin film becomes an issue. In principle, resins are organic substances, and their bonds are mainly based on covalent bonds, while oxides are ionic bonds, and their interfaces have different bond types, so a strong bond cannot be obtained. . In general, various adsorbed molecules are attached to the surface of the film, and even if the film is exposed to a vacuum, the surface of the film itself does not come out. From an industrial point of view, adhesion such as dirt adheres to the surface of the film, and release agents are unavoidably applied intentionally during film production.

Therefore, it becomes necessary to improve the adhesion between the resin substrate and the oxide. Various methods have been proposed, for example, a method of increasing the physical adhesion by using the so-called anchor effect by roughening the surface roughness, and wet cleaning of the film surface to remove dirt on the surface. method, introduction of a polar group such as a hydroxyl group that easily bonds with the oxide to the surface of the substrate in advance, and the like.

In addition, the plasma treatment that removes dirt on the film surface by applying plasma to the film surface and forms polar groups and radicals on the film surface does not greatly change the surface roughness and does not include processes such as drying. It has advantages and is widely used. In particular, the above-mentioned roll-to-roll apparatus has many advantages such as being able to continuously form a thin film after plasma-treating the film (Patent Document 1).

Furthermore, the introduction of an adhesion layer that mediates bonding between the resin and the oxide on the film surface has also been investigated. In particular, silicon has a metallic aspect, but since the bond is a covalent bond, it has a strong affinity with the resin. In addition, the substrate side is often pre _- formed with a hard coat containing an inorganic filler for the purpose of increasing the hardness of the surface and improving the lubricity. It is possible to provide strong adhesion between the surface and the adhesion layer of silicon (Patent Document 2). Furthermore, in order to improve the optical properties while forming a thick adhesion layer, a very small amount of oxygen was introduced during the silicon film formation, and silicon dioxide (SiOx: x = 1 to 2) in a partially oxygen-deficient state was used. There is also (Patent Document 3).

JP-A-7-166328 Japanese Patent No. 6207679 JP 2003-094546 A

However, when silicon is formed as an adhesion layer using a sputtering method, it is difficult to stably discharge the target, and once the target surface is oxidized, the discharge cannot be sustained. I'm holding In addition, when forming SiOx by introducing a very small amount of oxygen during silicon deposition, the degree of oxidation is not constant with respect to the amount of oxygen introduced, and the state of the target surface depends on the amount of oxygen introduced before hysteresis. It is extremely difficult to maintain film formation under the same conditions. Therefore, even when using a roll-to-roll sputtering process that can continuously form a film over a large area for a long time, it is possible to stably and firmly adhere the transparent substrate and the optical layer. Development of a technique capable of stably forming a layer is required.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical layered body in which a transparent substrate and an optical layer are firmly adhered, and an article having the same.

In order to solve the above-mentioned problems, the present inventors have made intensive studies, and as a result, have found conditions under which the transparent substrate and the optical layer can be firmly adhered to each other by using a metal material as the adhesion layer. That is, the present inventors have found that strong adhesion can be realized by forming a film between the base material and the oxide as an adhesion layer made of a metal material having a melting point of 700° C. or lower.
Therefore, the present invention provides the following means in order to solve the above problems.

An optical laminate according to an aspect of the present invention comprises a transparent substrate, an adhesion layer provided on at least one surface of the transparent substrate, and a surface of the adhesion layer opposite to the transparent substrate. wherein the adhesion layer is made of a metal material, the adhesion layer has a thickness of 8 nm or less, and the metal material has a melting point of 100° C. or more and 700° C. or less. Within range.

In the optical laminate according to one aspect of the present invention, the transparent substrate may be a resin film.

In the optical laminate according to one aspect of the present invention, the optical layer may be an oxide layer.

In the optical laminate according to one aspect of the present invention, the optical layer may be an alternate laminate in which high refractive index layers and low refractive index layers are alternately laminated.

The optical layered body according to one aspect of the present invention may have a configuration in which the transmittance of light having a wavelength of 550 nm is 91% or more.

An article according to one aspect of the present invention includes the optical layered body described above.

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the optical laminated body which the transparent base material and the optical layer adhere firmly, and the goods provided with the same.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows the optical laminated body which concerns on 1st Embodiment of this invention.

Hereinafter, this embodiment will be described in detail with appropriate reference to the drawings. In the drawings used in the following description, there are cases where characteristic portions are enlarged for convenience in order to make it easier to understand the features of the present invention, and the dimensional ratios of each component may differ from the actual ones. be. The materials, dimensions, etc. exemplified in the following description are examples, and the present invention is not limited to them, and can be implemented with appropriate modifications within the scope of the effects.

FIG. 1 is a cross-sectional view showing an optical laminate according to a first embodiment of the invention.
The optical layered body 10 of the present embodiment has an adhesive layer 12 and an optical layer 13 laminated in this order on one side of a transparent substrate 11 .

The transparent base material 11 may be made of a transparent material capable of transmitting light in the visible light range, and for example, a resin film is preferably used. Although the material of the resin film is not particularly limited, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyaramid, polyimide, polycarbonate, polyethylene, polypropylene, triacetyl cellulose (TAC), polycycloolefin ( COC, COP) and the like can be used.

The thickness of the transparent substrate 11 is not particularly limited, but in the case of a resin film, it is desirable to set it to 20 μm or more and 200 μm or less in consideration of ease of handling during manufacturing and thinning of the member. Further, the transparent substrate 11 preferably has a transmittance of 80% or more for light in the wavelength range used. The light transmittance of the transparent substrate 11 is more preferably 88% or higher, and particularly preferably 90% or higher.

Moreover, from the viewpoint of improving the abrasion resistance of the optical layered body 10, at least one surface of the transparent substrate 11 may be provided with, for example, a coating. A resin, an inorganic substance, or a mixture thereof can be used as the coating material. When a resin coating is used as the coating, organic or inorganic particles may be dispersed inside the resin coating for the purpose of improving the haze and film runnability of the optical layered body 10 . The resin coating may be formed by, for example, a solution coating method. In addition, the resin coating is provided on the surface of the transparent base material 11 on the side of the adhesion layer 12 , thereby providing an auxiliary effect for improving the adhesion between the transparent base material 11 and the optical layer 13 .

From the viewpoint of scratch resistance, resin-made coatings include those provided as a hard coat layer. As the binder resin used in the hard coat layer, a transparent one is preferable. For example, an ionizing radiation-curable resin, a thermoplastic resin, a thermosetting resin, etc., which are resins that are cured by ultraviolet rays or electron beams, can be used. .

Examples of the ionizing radiation-curable resin used as the binder resin of the hard coat layer include ethyl (meth)acrylate, ethylhexyl (meth)acrylate, styrene, methylstyrene, N-vinylpyrrolidone, and the like.
Examples of compounds that are ionizing radiation-curable resins having two or more unsaturated bonds include trimethylolpropane tri(meth)acrylate, tripropylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, and 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 ) acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, tripentaerythritol octa(meth)acrylate, tetrapentaerythritol deca(meth)acrylate, isocyanuric acid tri(meth)acrylate, isocyanuric acid di(meth)acrylate, polyester tri(meth)acrylate, polyester di(meth)acrylate, bisphenol di(meth)acrylate, diglycerin tetra(meth)acrylate, adamantyl di(meth)acrylate, Examples include polyfunctional compounds such as isobornyl di(meth)acrylate, dicyclopentane di(meth)acrylate, tricyclodecane di(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and the like. Among them, pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA) and pentaerythritol tetraacrylate (PETTA) are preferably used. In addition, "(meth)acrylate" refers to methacrylate and acrylate. As the ionizing radiation-curable resin, the above-mentioned compounds modified with PO (propylene oxide), EO (ethylene oxide), CL (caprolactone), etc. can also be used.

Examples of thermoplastic resins used as binder resins in the hard coat layer include styrene resins, (meth)acrylic resins, vinyl acetate resins, vinyl ether resins, halogen-containing resins, alicyclic olefin resins, and polycarbonate resins. , polyester resins, polyamide resins, cellulose derivatives, silicone resins and rubbers or elastomers. The thermoplastic resin is preferably amorphous and soluble in an organic solvent (especially a common solvent capable of dissolving a plurality of polymers and curable compounds). In particular, from the viewpoint of transparency and weather resistance, styrene-based resins, (meth)acrylic-based resins, alicyclic olefin-based resins, polyester-based resins, cellulose derivatives (cellulose esters, etc.), and the like are preferable.

Examples of thermosetting resins used as binder resins in the hard coat layer include phenol resins, urea resins, diallyl phthalate resins, melamine resins, guanamine resins, unsaturated polyester resins, polyurethane resins, epoxy resins, aminoalkyd resins, melamine- Urea cocondensation resins, silicon resins, polysiloxane resins (including so-called silsesquioxanes in basket-like and ladder-like forms) and the like can be mentioned.

The hard coat layer may contain an organic resin and an inorganic material, or may be an organic-inorganic hybrid material. One example is one formed by a sol-gel method. Examples of inorganic materials include silica, alumina, zirconia, and titania. Examples of organic materials include acrylic resins.

The filler contained in the hard coat layer can be selected from various fillers according to the application of the optical layered body 10 from the viewpoints of antiglare properties, adhesion with the optical layers described later, and antiblocking properties. Specifically, for example, known particles such as silica (Si oxide) particles, alumina (aluminum oxide) particles, and organic fine particles can be used.

The hard coat layer may contain, for example, a binder resin and silica particles and/or alumina particles as fillers. By dispersing silica particles and/or alumina particles as a filler in the hard coat layer, fine unevenness can be formed on the surface of the hard coat layer. These silica particles and/or alumina particles may be exposed on the surface of the hard coat layer on the optical layer 13 side. In this case, the binder resin of the hard coat layer and the adhesion layer 12 provided below the optical layer 13 are bonded. Therefore, the adhesion between the hard coat layer and the optical layer 13 is improved, the hardness of the hard coat layer is increased, and the scratch resistance of the optical layered body 10 is improved.
The average particle size of silica particles and/or alumina particles as fillers in the hard coat layer is, for example, 800 nm or less, preferably 780 nm or less, and more preferably 100 nm or less.

From the viewpoint of improving the antiglare property of the optical layered body 10, organic fine particles can be used as the filler contained in the hard coat layer. Examples of organic fine particles include acrylic resins. The particle diameter of the organic fine particles is preferably 10 μm or less, more preferably 7 μm or less, even more preferably 5 μm or less, and particularly preferably 3 μm or less.
As the filler contained in the hard coat layer, various reinforcing materials can be used in order to impart toughness to the hard coat layer, as long as the optical properties are not impaired. Examples of reinforcing materials include cellulose nanofibers.

Although the thickness of the hard coat layer is not particularly limited, for example, it is preferably 0.5 μm or more, more preferably 1 μm or more. The thickness of the hard coat layer is preferably 100 μm or less. When the thickness of the hard coat layer is 0.5 μm or more, sufficient hardness is obtained, so that scratches are less likely to occur during manufacturing. Further, when the thickness of the hard coat layer is 100 μm or less, the thickness and weight of the optical layered body 10 can be reduced. Further, when the thickness of the hard coat layer is 100 μm or less, microcracks in the hard coat layer, which occur when the optical layered body 10 is bent during manufacturing, are less likely to occur, resulting in good productivity.

The hard coat layer may be a single layer or a laminate of multiple layers. Further, the hard coat layer may be further provided with known functions such as ultraviolet absorption performance, antistatic performance, refractive index adjustment function, and hardness adjustment function.
Moreover, the function imparted to the hard coat layer may be imparted in a single hard coat layer, or may be imparted in a plurality of divided layers.

The transparent substrate 11 is not limited to a resin film. The transparent substrate 11 may be glass, for example. The glass may be a flat plate, or may have a shape having an uneven surface such as a lens.

The adhesion layer 12 is a layer that adheres the transparent substrate 11 and the optical layer 13 together.
The adhesion layer 12 is made of a metal material having a melting point of 700° C. or lower. The metal material may be a single metal or an alloy. Examples of metal materials include metals such as Al, Pb, Sn, In, Zn, and Bi. These metals may be single or alloys containing multiple elements. In the case of Al or the like, a natural oxide film is formed, but this natural oxide film is treated as a metal film. When the metal material is an alloy, the melting point of each of the constituent elements contained in the alloy may be 700° C. or higher as long as the composition of the film formed has a melting point of 700° C. or lower. If the adhesion layer 12 is too thin, it may not form a layer and its constituent atoms may be localized, causing light absorption or impairing adhesion. Therefore, the film thickness of the adhesion layer 12 is preferably 0.5 nm or more. Moreover, when the film thickness of the adhesion layer 12 exceeds 8 nm, the absorption of light by the adhesion layer 12 becomes remarkable, and there is a possibility that the light transmittance of the optical layered body 10 is impaired. Therefore, the film thickness of the adhesion layer 12 is preferably in the range of 0.5 nm or more and 8 nm or less.

A method for forming the adhesion layer 12 may be, for example, a vacuum film formation method, and is not particularly limited, but it is preferable to use a sputtering method for the purpose of obtaining adhesion.
Normally, in the sputtering method, rare gas ions accelerated by plasma collide with the adherend (sputtering target) placed on the cathode side. Atoms of the adherend collide with the arranged substrate surface to form a film. At this time, it is known that the atoms move on the surface without immediately stopping on the substrate. As the atoms move, they lose energy and eventually adhere to the surface. Therefore, the greater the applied energy, the more the particles diffuse on the surface and the more uniform the film can be formed. The thermal load increases, and the transparent substrate 11 itself may be deformed. This phenomenon becomes more remarkable as the thickness of the transparent substrate 11 becomes thinner.

In addition, when a metal material with a high melting point is used as a sputtering target, sufficient energy cannot be obtained by sputtering at low power, and metal atoms aggregate on the surface of the transparent substrate 11 to form fine metal particles. This can lead to absorption of light.

The present inventor conducted studies by forming metal material films by a sputtering method using various metal materials, and found that all metal material films with excellent adhesion have a low melting point. That is, by using a metal material having a melting point of 700° C. or less, even if the transparent substrate 11 is a resin film, it is possible to form a strong adhesion layer 12 without causing deformation due to thermal load. Found it.
When the adhesion layer 12 is formed using a metal material having a melting point of 700° C. or lower, less electric power is required to obtain the same film formation rate as compared with the case of using a high melting point metal material. Furthermore, even if the distance to move after reaching the transparent substrate 11 and stop on the substrate surface is long and the surface shape is complicated, a uniform film is formed with good followability.
Therefore, the optical layer 13 that is subsequently formed does not come into direct contact with the transparent substrate 11, but is bonded to the transparent substrate 11 via the adhesion layer 12 made of a metal material with a low melting point. Strong adhesion can be obtained even when the base material 11 is a resin film.
The metal material used for the adhesion layer 12 may have a melting point of 700° C. or lower, but the melting point must be 100° C. or higher from the viewpoint of sputtering target manufacturing and processes.

The optical layer 13 is a layer for obtaining an optical effect, which is the purpose of the optical laminate 10 . The optical effect is an effect of controlling properties of light such as reflection, transmission, and refraction, and includes, for example, antireflection effect, selective reflection effect, antiglare effect, and lens effect. In FIG. 1, the optical layer 13 is an alternately laminated body in which two high refractive index layers 13a and two low refractive index layers 13b are alternately laminated. Although the number of layers of the high refractive index layer 13a and the number of the low refractive index layers 13b are two in FIG. In addition, the optical layer 13 can be laminated in material, configuration, and film thickness according to its purpose. The optical layer 13 may be a single layer.

When the optical layer 13 is used as an antireflection layer, the structure is an alternate laminate in which high refractive index layers 13a having a refractive index of 1.9 or more and low refractive index layers 13b having a refractive index of 1.6 or less are alternately laminated. may be In particular, an alternate laminate in which the first high refractive index layer 13a, the first low refractive index layer 13b, the second high refractive index layer 13a, and the second low refractive index layer 13b are laminated in this order from the transparent substrate 11 side. is often used from the viewpoint of industrial productivity as well as ensuring sufficient optical properties. In general, the high refractive index layer 13a and the low refractive index layer 13b are each preferably transparent. In order to form the transparent high refractive index layer 13a and the low refractive index layer 13b, it is preferable to use these as oxides. Of course, even if a layer having optical absorption is intentionally formed in order to realize an optical function, it does not deviate from the spirit of the present invention. Further, a substance other than an oxide, such as an organic substance, may intervene with the intention of imparting functionality to the optical layer surface or the lamination interface excluding the interface with the substrate.

The refractive index of the high refractive index layer 13a is preferably 2.00 to 2.60, more preferably 2.10 to 2.45. Such high refractive index oxides include niobium oxide (Nb ₂ O ₅ , refractive index 2.33), titanium oxide (TiO ₂ , refractive index 2.33 to 2.55), tungsten oxide (WO ₃ , refractive index 2.2), cerium oxide (CeO ₂ , refractive index 2.2), tantalum pentoxide (Ta ₂ O ₅ , refractive index 2.16), zinc oxide (ZnO, refractive index 2.1), indium oxide Tin (ITO, refractive index 2.06) and the like can be mentioned.

The refractive index of the low refractive index layer 13b is preferably 1.20 to 1.60, more preferably 1.30 to 1.50. As such a low refractive index oxide, an oxide containing SiO ₂ (an oxide of Si) or the like as a main component can be used. The oxide, including the oxide of Si, may contain another element within 50%. For example, Na may be included for the purpose of improving durability, and Zr, Al, or N may be included for the purpose of improving hardness. The content of these elements is preferably 10% or less.

By alternately laminating the high refractive index layers 13a and the low refractive index layers 13b, the light incident from the side opposite to the transparent substrate 11 interferes with each other, thereby reducing the intensity of the reflected light. , the antireflection function can be exhibited.

The high refractive index layer 13a and the low refractive index layer 13b that constitute the optical layer 13 can be formed by sputtering, for example.

When the adhesion layer 12 and the optical layer 13 are formed by a sputtering method, for example, a thin film forming apparatus described in JP-A-2014-34701 can be used. For example, this thin film forming apparatus includes a supply unit for taking out the transparent substrate 11 from the unwinding roll and a resin coating in the case of providing a resin coating on the transparent substrate 11 (on the optical layer 13 side) in a vacuum chamber (chamber). It has a film forming chamber unit for forming the adhesion layer 12 and the optical layer 13 on the coating film to form the optical layered body 10 and a winding section for winding the optical layered body 10 . The film forming chamber unit has a cathode section in which sputtering targets for forming the adhesion layer 12 and the optical layer 13 are installed. When the adhesive layer 12 is one layer and the optical layer 13 is an alternate laminate in which two layers of the high refractive index layer 13a and the low refractive index layer 13b are alternately laminated (when forming a total of five layers), Five cathode sites are used.

That is, the above-described thin film forming apparatus performs film formation by sputtering on a transparent substrate 11 such as a resin film by a roll-to-roll method, and can set a plurality of sputtering targets. Once the rolls are set, it is possible to deposit a plurality of different materials while maintaining the vacuum atmosphere. Furthermore, in the thin film forming apparatus described above, oxygen gas can be introduced into the plasma in addition to argon gas, which is a sputtering gas, during sputtering, thereby forming an oxide of the sputtering target material on the transparent substrate 11. be able to.

In the optical laminate 10 of the present embodiment, an antifouling layer may be provided on the surface of the optical layer 13 opposite to the adhesion layer 12 side. As a material for the antifouling layer, a fluorine-based organic compound can be used. Examples of fluorine-based organic compounds include compounds composed of a fluorine-modified organic group and a reactive silyl group (eg, alkoxysilane). Fluorinated organic compounds may be used singly or in combination of two or more.

In addition, in the optical layered body 10 of the present embodiment, various layers may be provided on the surface of the transparent substrate 11 opposite to the adhesive layer 12 side, if necessary. For example, a pressure-sensitive adhesive layer that is used for bonding with other members may be provided. Moreover, another optical film may be provided via this adhesive layer. Examples of other optical films include polarizing films, retardation compensation films, and films functioning as half-wave plates and quarter-wave plates.

According to the optical layered body 10 of the present embodiment configured as described above, the adhesion layer 12 interposed between the transparent substrate 11 and the optical layer 13 has a melting point in the range of 100° C. or higher and 700° C. or lower. The transparent substrate 11 and the optical layer 13 can be firmly adhered to each other because they are made of a certain metal material. That is, a metal material having a melting point in the range of 100° C. or higher and 700° C. or lower can be formed into a film by a sputtering method with relatively low power. It becomes possible to form a material film (adhesion layer 12). By uniformly forming the adhesion layer 12 on the surface of the transparent base material 11 , the optical layer 13 is less likely to come into direct contact with the surface of the transparent base material 11 , and the optical layer 13 does not form on the surface of the adhesion layer 12 . Since the film is formed uniformly, the adhesion between the transparent substrate 11 and the optical layer 13 is improved.
In addition, when the transparent base material 11 is provided with a resin film, the same effect as described above when the transparent base material 11 is a resin film can be applied to the resin film.

In the optical layered body 10 of the present embodiment, when the thickness of the adhesion layer 12 is 0.5 nm or more, the transparent substrate 11 and the optical layer 13 can be adhered to each other more reliably. Moreover, when the thickness of the adhesion layer 12 is 8 nm or less, the absorption of light by the adhesion layer 12 can be suppressed to a level that poses no practical problem.

According to the optical layered body 10 of the present embodiment, even when the transparent substrate 11 is a resin film and the optical layer 13 is an oxide layer, it is possible to firmly adhere them.

In the optical layered body 10 of the present embodiment, when the optical layer 13 is an alternating layered body in which high refractive index layers 13a and low refractive index layers 13b are alternately layered, it can be used as an antireflection film. In particular, when the transmittance of light with a wavelength of 550 nm is 91% or more, it can be advantageously used as an antireflection film.

The article of the present embodiment has the optical layered body 10 described above on the display surface of the image display section, such as a liquid crystal display panel or an organic EL display panel. As a result, for example, high wear resistance can be imparted to the touch panel display portion of a smartphone or operation device, and an image display device with excellent durability can be realized.

The article is not limited to an image display device, and includes, for example, a window glass or goggles on which the optical layered body of the present embodiment is provided, a light-receiving surface of a solar cell, a screen of a smartphone, or a display of a personal computer. Information input terminals, tablet terminals, electronic display boards, glass table surfaces, game machines, operation support devices for aircraft and trains, navigation systems, dashboards, surfaces of optical sensors, etc., as long as the optical laminate 10 can be applied. , can be anything.

Although the embodiment of the present invention has been described above, this embodiment is presented as an example and is not intended to limit the scope of the invention. This embodiment can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, as well as the scope of the invention described in the claims and equivalents thereof.

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In addition, Examples 1, 7, and 8 are reference examples.

[Example 1]
As the transparent substrate 11, a resin film was prepared by forming a 4 μm thick acrylic resin coating (hard coat layer) containing silicon oxide fine particles on 80 μm thick TAC. An adhesion layer 12 and an optical layer 13 were successively formed on the acrylic resin coating of this resin film by a sputtering method using a thin film forming apparatus.

The acrylic resin film was formed by applying a coating liquid having the composition shown in Table 1 below onto the transparent substrate 11 using a bar coater, and curing the coating by irradiating it with ultraviolet rays for photopolymerization.

As a thin film forming apparatus, the apparatus described in JP-A-2014-34701 was used. This thin film forming apparatus can sequentially laminate thin films of a plurality of materials at the same time. In this example, the sputtering targets of aluminum, niobium oxide, silicon, niobium oxide, and silicon were arranged in this order from the side closer to the unwinding side of the resin film. Each sputtering target is connected to an independent power supply, and can be discharged by supplying arbitrary power. In addition, each sputtering target is stored in an independent container, and the partition wall separating the sputtering targets has only a slight gap near the can roll, making it possible to realize substantially different gas atmospheres. be.

The entire vacuum chamber of this thin film forming apparatus was evacuated to 1×10 ⁻³ Pa or less. Next, argon gas was introduced into the first cathode section where the aluminum target was installed while adjusting the flow rate with a mass flow controller so that the flow rate was 150 sccm, and electric power was applied to the aluminum target to discharge it, and a film was formed by sputtering. did At this time, the running speed of the resin film was 3 m/min. Met. The electric power applied to the aluminum target was determined by measuring the relationship between the electric power and the film thickness of the aluminum film formed in advance, and the traveling speed was set to 3 m/min. was adjusted so that an aluminum film having a film thickness of 0.5 nm could be formed on the resin film.

After forming an aluminum film (adhesion layer) on the first cathode portion, a niobium oxide film (high refractive index layer 13a) was formed on the second cathode portion. An argon gas was introduced into the second cathode portion while adjusting the flow rate thereof with a mass flow controller to a flow rate of 150 sccm, electric power was applied to the niobium oxide target to cause discharge, and film formation was performed by sputtering. At this time, a small amount of oxygen was introduced separately from the argon gas while being adjusted by a mass flow controller, and the amount of oxygen was adjusted so as not to cause light absorption due to lack of oxygen, thereby obtaining a good niobium oxide film. The electric power applied to the niobium oxide target was determined by measuring the relationship between the electric power and the film thickness of the niobium oxide film formed in advance, and the moving speed was set to 3 m/min. was adjusted so that a niobium oxide layer having a thickness of 10 nm could be formed on the resin film.

After forming a niobium oxide film (high refractive index layer) on the second cathode portion, a silicon oxide film (low refractive index layer) was formed on the third cathode portion. An argon gas was introduced into the third cathode portion while being adjusted by a mass flow controller so as to have a flow rate of 150 sccm, and electric power was applied to the silicon target to cause discharge to form a film by sputtering. At this time, a good silicon oxide film was obtained by introducing oxygen separately from the argon gas while controlling it with a mass flow controller. The power applied to the silicon target was determined by measuring the relationship between the power and the film thickness of the silicon oxide film formed in advance, and the moving speed was set to 3 m/min. was adjusted so that a silicon oxide film having a film thickness of 40 nm could be formed on the resin film.

Similarly, a niobium oxide film was formed on the fourth cathode portion, and then a silicon oxide film was formed on the fifth cathode portion. At that time, the electric power was adjusted so that the thickness of the niobium oxide film was 100 nm in the fourth cathode portion and the thickness of the silicon oxide film was 90 nm in the fifth cathode portion.

As described above, one adhesive layer 12 and an optical layer, which is an alternately laminated body in which four high-refractive index layers and low-refractive index layers are alternately laminated, are formed on the resin film. , an optical laminate (antireflection film) having the configuration shown in FIG. 1 was produced. After the optical layered body was continuously wound up, the air was introduced into the whole vacuum chamber of the thin film forming apparatus, and the wound optical layered body was taken out.

Although one layer was formed using one cathode in this embodiment, it is not always necessary to use one cathode. A single layer may be formed using a plurality of cathodes in consideration of thermal and power loads.

[Example 2]
An optical laminate was produced under the same conditions as in Example 1, except that the thickness of the aluminum film (adhesion layer) in the first cathode portion was adjusted to 1 nm.

[Example 3]
An optical laminate was produced under the same conditions as in Example 1, except that the thickness of the aluminum film (adhesion layer) in the first cathode portion was adjusted to 2 nm.

[Example 4]
An optical laminate was produced under the same conditions as in Example 1, except that the thickness of the aluminum film (adhesion layer) in the first cathode portion was adjusted to 4 nm.

[Example 5]
An optical laminate was produced under the same conditions as in Example 1, except that the thickness of the aluminum film (adhesion layer) in the first cathode portion was adjusted to 6 nm.

[Example 6]
An optical laminate was produced under the same conditions as in Example 1, except that the thickness of the aluminum film (adhesion layer) in the first cathode portion was adjusted to 8 nm.

[Example 7]
In the first cathode section, an optical laminate was fabricated under the same conditions as in Example 1, except that a zinc target was used instead of the aluminum target and the film thickness of the zinc film (adhesion layer) was adjusted to 2 nm. made.

[Example 8]
An optical laminated body was manufactured under the same conditions as in Example 1, except that a tin target was used instead of an aluminum target in the first cathode portion, and the film thickness of the tin film (adhesion layer) was adjusted to 2 nm. made.

[Example 9]
An optical laminated body was manufactured under the same conditions as in Example 1, except that an indium target was used in place of the aluminum target in the first cathode portion, and the thickness of the indium film (adhesion layer) was adjusted to 2 nm. made.

[Comparative Example 1]
An optical layered body was produced under the same conditions as in Example 1, except that the cathode portion was not discharged and the aluminum film was not formed in the first cathode portion.

[Comparative Example 2]
An optical laminated body was manufactured under the same conditions as in Example 1, except that a titanium target was used in place of the aluminum target in the first cathode portion, and the film thickness of the titanium film (adhesion layer) was adjusted to 1 nm. made.

[Comparative Example 3]
An optical laminated body was manufactured under the same conditions as in Example 1, except that a titanium target was used in place of the aluminum target in the first cathode portion, and the film thickness of the titanium film (adhesion layer) was adjusted to 2 nm. made.

[Comparative Example 4]
An optical laminated body was manufactured under the same conditions as in Example 1, except that a titanium target was used instead of an aluminum target in the first cathode portion, and the film thickness of the titanium film (adhesion layer) was adjusted to 3 nm. made.

[Comparative Example 5]
An optical laminated body was manufactured under the same conditions as in Example 1, except that a titanium target was used instead of an aluminum target in the first cathode portion, and the film thickness of the titanium film (adhesion layer) was adjusted to 4 nm. made.

[Comparative Example 6]
An optical laminate was fabricated under the same conditions as in Example 1, except that a silver target was used in place of the aluminum target in the first cathode portion and the film thickness of the silver film (adhesion layer) was adjusted to 2 nm. made.

[Comparative Example 7]
An optical laminate was manufactured under the same conditions as in Example 1, except that a silver target was used in place of the aluminum target in the first cathode portion and the film thickness of the silver film (adhesion layer) was adjusted to 4 nm. made.

[Comparative Example 8]
An optical laminate was fabricated under the same conditions as in Example 1, except that a germanium target was used in place of the aluminum target in the first cathode portion, and the film thickness of the germanium film (adhesion layer) was adjusted to 2 nm. made.

[Comparative Example 9]
An optical laminate was fabricated under the same conditions as in Example 1, except that a germanium target was used in place of the aluminum target in the first cathode portion, and the film thickness of the germanium film (adhesion layer) was adjusted to 4 nm. made.

[Comparative Example 10]
An optical laminate was fabricated under the same conditions as in Example 1, except that a tungsten target was used in place of the aluminum target in the first cathode portion and the film thickness of the tungsten film (adhesion layer) was adjusted to 2 nm. made.

[Comparative Example 11]
An optical laminate was fabricated under the same conditions as in Example 1, except that a tungsten target was used in place of the aluminum target in the first cathode portion, and the film thickness of the tungsten film (adhesion layer) was adjusted to 4 nm. made.

[Comparative Example 12]
An optical laminate was manufactured under the same conditions as in Example 1, except that an indium target was used instead of an aluminum target in the first cathode portion, and the thickness of the indium film (adhesion layer) was adjusted to 10 nm. made.

[Evaluation results]
The following measurements and evaluations were performed on samples prepared by cutting the optical laminates obtained in Examples and Comparative Examples into arbitrary sizes. The results are shown in Table 2 below together with the metal materials constituting the adhesion layer, the bulk melting point of the metal, and the film thickness of the adhesion layer.

(Total light transmittance)
The total light transmittance was measured using "NDH5000" (manufactured by Nippon Denshoku Industries Co., Ltd.) according to "JIS K-7105". In the present invention, it is preferable that light absorption by the adhesive layer is small. Therefore, in the case of the optical laminates (antireflection films) produced in Examples and Comparative Examples, it is desirable that the total light transmittance is high. TAC film without an antireflection film has a transmittance of about 90%. is preferably 91% or more.

(Adhesion)
Adhesion was evaluated by the cross-hatch method in accordance with "JIS K5400". That is, 11 cuts were made at intervals of 1 mm on the surface of the sample on the side of the optical layered body with a cutter, and 11 cuts were made so as to be perpendicular to the cuts, thereby forming 100 squares. The sample with the squares formed thereon is allowed to stand for 2 hours under conditions of a temperature of 25° C. and a relative humidity of 60% RH. This is repeated three times, and the number of squares peeled off is counted with an optical microscope or the like. It should be noted that when one-third or more of each square is peeled off, it is regarded as peeling. The number of squares left without being peeled off (remaining number) is measured, and the number of peeled squares relative to the total number of squares (100 squares) is used as an index of adhesion.
Long-term durability is important for optical laminates, not only in the initial stage immediately after production. For this reason, an environmental test was conducted in which the sample was allowed to stand for 500 hours in an environment of a temperature of 85° C. and a relative humidity of 85% RH, and the adhesion of the environmental test sample was similarly evaluated.
It is preferable that the adhesiveness is high, and that the number of squares left without being peeled off in the cross-hatch method (number of residuals) is high.

As is clear from Table 2, the optical laminates of Examples 1 to 6, in which an aluminum film having a bulk melting point of 660° C. was used as the adhesion layer, varied in total light transmittance depending on the thickness of the adhesion layer. , the film thickness is 91% or more, which is good. In addition, it can be said that the adhesion at the initial stage and after the environmental test is sufficient. Optical laminates of Examples 7, 8, and 9, in which adhesion layers are made of zinc film (melting point 420° C.), tin film (232° C.), and indium (157° C.), which have a lower melting point than aluminum film. Also, excellent results were obtained in both total light transmittance and adhesion.
The above results show that by using a metal material with a melting point of 700° C. or less, a uniform metal material film is formed on the surface of the resin film when the adhesion layer is formed, and both good optical properties and adhesion are achieved. shows what you can do.

The optical layered body of Comparative Example 1, in which no adhesion layer was formed, had a low total light transmittance. Presumed. In addition, it was confirmed that the optical layered body of Comparative Example 1 was poor in adhesion, as peeling was observed even in the initial stage. Therefore, the environmental test was omitted.

The optical laminates of Comparative Examples 2 to 5, in which the adhesion layer was a titanium film having a bulk melting point of 1668° C., were able to secure initial adhesion. However, the adhesion after the environmental test was inadequate. Although the adhesion was improved by increasing the thickness of the adhesion layer, there was a tendency for the total light transmittance to decrease as the thickness of the adhesion layer increased. For this reason, it was not possible to find a condition that satisfies both the total light transmittance and the adhesion after the environmental test.

In the optical laminates 10 of Comparative Examples 6 and 7 in which a silver film having a bulk melting point of 962° C. was used as the adhesion layer, in Comparative Example 6 in which the adhesion layer had a thickness of 2 nm, both the initial adhesion and the total light transmittance were low. rice field. This is probably because silver tends to aggregate. Therefore, in Comparative Example 6, the environmental test was omitted. On the other hand, in the optical laminate of Comparative Example 7 having a film thickness of 4 nm, the initial adhesion and total light transmittance were acceptable, but the adhesion after the environmental test was insufficient.

The optical laminates of Comparative Examples 8 and 9, in which the germanium film having a bulk melting point of 938° C. was used as the adhesion layer, could secure the total light transmittance and the initial adhesion. However, the adhesion after the environmental test was low in all cases.

The optical laminates of Comparative Examples 10 and 11, in which a tungsten film having a bulk melting point of 3422° C. was used as an adhesive layer, ensured the total light transmittance. However, in Comparative Example 10 in which the adhesion layer had a thickness of 2 nm, the initial adhesion was low. Therefore, the environmental test was omitted. Further, in Comparative Example 11, in which the adhesion layer had a thickness of 4 nm, the adhesion was low after the environmental test.

Comparative Example 12, in which an indium film having a bulk melting point of 157° C. and a thickness of 10 nm is used as an adhesion layer, resulted in a total light transmittance of less than 91%. This indicates that the thickness of the adhesion layer is affected by light absorption, and if the thickness of the adhesion layer exceeds 8 nm, it is practically disadvantageous.

As described above, the effects of the present invention could be demonstrated from the results of Examples and Comparative Examples.

DESCRIPTION OF SYMBOLS 10... Optical laminated body 11... Transparent base material 12... Adhesion layer 13... Optical layer 13a... High refractive index layer 13b... Low refractive index layer

Claims (7)

A transparent substrate, a resin coating provided on at least one surface of the transparent substrate, an adhesion layer formed on the resin coating, and a surface of the adhesion layer opposite to the transparent substrate. An optical layered body having an optical layer formed in
the adhesion layer is made of Al or In,
The adhesion layer has a thickness of 1 nm or more and 8 nm or less ,
An optical laminate , wherein the optical layer is an oxide layer . 2. The optical laminate according to claim 1, wherein the transparent substrate is a resin film. 3. The optical layered body according to claim 1, wherein the optical layer is an alternate layered body in which high refractive index layers and low refractive index layers are alternately layered to form a total of four or more layers. 4. The optical laminate according to claim 3 , wherein the high refractive index layer is laminated on the surface of the adhesion layer opposite to the transparent substrate. A transparent substrate, a resin coating provided on at least one surface of the transparent substrate, an adhesion layer formed on the resin coating, and a surface of the adhesion layer opposite to the transparent substrate. An optical layered body having an optical layer formed in
the adhesion layer is made of Al or In,
The adhesion layer has a thickness of 1 nm or more and 8 nm or less,
The optical layer is an alternate laminate in which a high refractive index layer and a low refractive index layer are alternately laminated,
An optical laminate, wherein the high refractive index layer made of a niobium oxide film is laminated on the surface of the adhesive layer opposite to the transparent substrate. The optical layered body according to any one of claims 1 to 5 , which has a transmittance of 91% or more for light having a wavelength of 550 nm. An article comprising the optical layered body according to any one of claims 1 to 6 .

Images