Titanium oxide film and method for producing the same

Abstract

The present invention provides a titanium oxide film with excellent anti-reflective properties and manufacturing efficiency, as well as a method for producing the same. [Solution] The titanium oxide film 1 contains a crystal in which a group of Ti2O3 diffraction spots appear in the electron diffraction pattern observed with a transmission electron microscope, and the refractive index when light with a wavelength of 550 nm is incident on it is greater than 2.50 and less than or equal to 2.80.

Description

[Technical Field]

[0001] The present invention relates to a titanium oxide film and a method for producing the same. [Background technology]

[0002] In image display devices such as liquid crystal displays and organic EL displays, an anti-reflective film is placed on the outermost surface of the display screen to prevent reflection of ambient light. Such an anti-reflective film comprises a transparent substrate film and an anti-reflective layer including a high refractive index layer and a low refractive index layer.

[0003] As a high refractive index layer used in such anti-reflective films, a rutile-type titanium oxide (TiO2) film has been proposed (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2014-016459 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, the rutile-type TiO2 film described above is manufactured by annealing at high temperatures of 600°C or higher for a long period of time after film formation, which requires time for heating and cooling. Furthermore, the roll-to-roll film formation method does not allow for annealing at high temperatures of 600°C or higher for a long period of time, resulting in a decrease in the production efficiency of titanium oxide films. On the other hand, by forming titanium oxide using the magnetron sputtering method (DCMS) with a DC power supply, a rutile-type TiO2 film can be formed using the roll-to-roll method, but the film formation rate remains at around 0.005 nm / sec, resulting in a decrease in the production efficiency of titanium oxide films.

[0006] Furthermore, when a titanium oxide film is used as a high refractive index layer in an anti-reflective film, an even higher refractive index is required to reduce the reflectivity of ambient light. On the other hand, if the refractive index is too high, wavelength dispersion of ambient light occurs, and the reflectivity of the anti-reflective film does not decrease over a wide wavelength range.

[0007] The present invention aims to provide a titanium oxide film with excellent anti-reflective properties and manufacturing efficiency, and a method for producing the same. [Means for solving the problem]

[0008] The present invention [1] includes a titanium oxide film comprising a crystal in which a group of Ti2O3 diffraction spots appear in an electron diffraction pattern observed with a transmission electron microscope, and in which the refractive index when light with a wavelength of 550 nm is incident is greater than 2.50 and less than or equal to 2.80.

[0009] The present invention [2] includes the titanium oxide film described in [1], wherein the refractive index is greater than 2.68.

[0010] The present invention [3] is a method for producing a titanium oxide film as described in [1], and includes a step of forming a titanium oxide film on one side in the thickness direction of a substrate using high-power impulse magnetron sputtering (HiPIMS) at a film formation temperature of 70°C or higher.

[0011] The present invention [4] includes a method for producing a titanium oxide film according to [3], wherein the film formation temperature is set to 100°C or higher and the above steps are carried out.

[0012] The present invention [5] includes a method for producing a titanium oxide film according to [3] or [4], wherein the step is carried out in a roll-to-roll manner. [Effects of the Invention]

[0013] The titanium oxide film of the present invention contains crystals in which a group of Ti2O3 diffraction spots appear in the electron diffraction pattern observed with a transmission electron microscope, and the refractive index when incident with light of a wavelength of 550 nm is greater than 2.50 and less than or equal to 2.80. Therefore, when the titanium oxide film is used in an anti-reflective film, the anti-reflective film has excellent anti-reflective performance, and the titanium oxide film does not require annealing at high temperatures of 600°C or higher for a long time, unlike rutile-type TiO2 films, and has a high film deposition rate, resulting in excellent manufacturing efficiency for the titanium oxide film.

[0014] The present invention relates to a method for manufacturing a titanium oxide film, which includes a step of forming a titanium oxide film on one side of the thickness direction of a substrate using high-power impulse magnetron sputtering (HiPIMS) at a deposition temperature of 70°C or higher. The titanium oxide film produced by the present invention contains crystals in which a group of Ti2O3 diffraction spots appears in the electron diffraction pattern observed with a transmission electron microscope, and the refractive index when light with a wavelength of 550 nm is incident on it is greater than 2.50 and less than or equal to 2.80. Therefore, when the titanium oxide film is used as an anti-reflective film, the anti-reflective film has excellent anti-reflective performance, and unlike rutile-type TiO2 films, it does not require annealing at high temperatures of 600°C or higher for a long time, and the deposition rate is high, resulting in excellent manufacturing efficiency of the titanium oxide film. [Brief explanation of the drawing]

[0015] [Figure 1] Figure 1 shows one embodiment of a laminate comprising the titanium oxide film of the present invention. [Figure 2] Figures 2A and 2B show one embodiment of the method for producing a titanium oxide film according to the present invention. Figure 2A shows the first step of preparing a substrate, and Figure 2B shows the second step of forming a titanium oxide film on one side of the substrate in the thickness direction. [Modes for carrying out the invention]

[0016] 1. Titanium oxide film One embodiment of the titanium oxide film of the present invention will be described.

[0017] As shown in FIG. 1, for example, the titanium oxide film 1 is one of the laminated elements of the laminate X described later. The titanium oxide film 1 is the uppermost layer of the laminate X. Specifically, the titanium oxide film 1 is disposed on one side in the thickness direction of the protective layer 23 described later. That is, the titanium oxide film 1 is in contact with the protective layer 23.

[0018] The titanium oxide film 1 has a film shape (including a sheet shape) with a predetermined thickness. Further, the titanium oxide film 1 extends in a plane direction orthogonal to the thickness direction, and one side and the other side in the thickness direction of the titanium oxide film 1 are flat.

[0019] The titanium oxide film 1 is a crystalline layer. The titanium oxide film 1 may contain an amorphous region. Preferably, the titanium oxide film 1 is a layer that contains only a crystalline region and does not contain an amorphous region. The amorphous region is identified, for example, by observation in the plane direction of the titanium oxide film 1 with a transmission electron microscope.

[0020] The titanium oxide film 1 contains an oxide of titanium (Ti). Specifically, the titanium oxide film 1 contains crystals in which a diffraction spot group of Ti2O3 appears in an electron diffraction image observed with a transmission electron microscope. In addition to the crystals in which a diffraction spot group of Ti2O3 appears, the titanium oxide film 1 may contain crystals in which other diffraction spot groups other than Ti2O3 appear. Specifically, the titanium oxide film 1 may contain crystals in which a diffraction spot group of rutile-type TiO2, anatase-type TiO2, brookite-type TiO2, and TiO appears. Preferably, in the titanium oxide film 1, only a diffraction spot group of Ti2O3 appears in an electron diffraction image observed with a transmission electron microscope, and no other diffraction spot groups other than Ti2O3 appear. The crystal structure contained in the titanium oxide film 1 is identified in detail by analysis of the electron diffraction image described later.

[0021] The titanium oxide film 1 of the present invention contains crystals in which a group of Ti2O3 diffraction spots appear in the electron diffraction pattern observed with a transmission electron microscope. Therefore, the titanium oxide film 1 can be manufactured without annealing at high temperatures of 600°C or higher for a long period of time, as is done when depositing rutile-type TiO2. Consequently, the manufacturing efficiency of the titanium oxide film 1 is excellent.

[0022] In titanium oxide film 1, the grain size of Ti2O3 is, for example, 5 nm or more, preferably 6 nm or more, more preferably 8 nm or more, and even more preferably 10 nm or more, and also, for example, 30 nm or less, preferably 28 nm or less, more preferably 26 nm or less, and even more preferably 25 nm or less. The grain size of Ti2O3 in titanium oxide film 1 can be determined, for example, by observing the crystal grains in the plane direction of titanium oxide film 1 with a transmission electron microscope.

[0023] In the titanium oxide film 1, if the crystal grain size of Ti2O3 is within the upper and lower limits described above, the refractive index when light with a wavelength of 550 nm is incident on the titanium oxide film 1 will be greater than 2.50 and less than or equal to 2.80. In other words, when the titanium oxide film 1 is used as a high refractive index layer in an anti-reflective film, the reflection of ambient light is suppressed, and the anti-reflective film exhibits excellent anti-reflective performance.

[0024] The refractive index of the titanium oxide film 1 when light with a wavelength of 550 nm is incident on it is greater than 2.50, preferably greater than 2.60, more preferably greater than 2.68, even more preferably greater than 2.70, and also 2.80 or less, preferably 2.78 or less, more preferably 2.77 or less, and even more preferably 2.75 or less. The refractive index of the titanium oxide film 1 when light with a wavelength of 550 nm is incident on it is determined by refractive index measurement as described later.

[0025] If the refractive index of the titanium oxide film 1 when light with a wavelength of 550 nm is incident on it is within the upper and lower limits described above, then when the titanium oxide film 1 is used as a high refractive index layer in an anti-reflective film, the reflection of ambient light is suppressed, and the anti-reflective film exhibits excellent anti-reflective performance.

[0026] The thickness of the titanium oxide film 1 is not particularly limited, but for example, it is 10 nm or more, preferably 20 nm or more, more preferably 30 nm or more, and even more preferably 40 nm or more. Alternatively, for example, it may be 250 nm or less, preferably 200 nm or less, more preferably 150 nm or less, and even more preferably 100 nm or less. The thickness of the titanium oxide film 1 can be determined, for example, by measuring the cross-section of the titanium oxide film 1 in the thickness direction using a FE-TEM (product name: JEM-2800, manufactured by JEOL).

[0027] If the thickness of the titanium oxide film 1 is below the upper limit mentioned above, the refractive index of the titanium oxide film 1 can be increased. When the titanium oxide film 1 is used as a high refractive index layer in an anti-reflective film, the reflection of ambient light is suppressed, and the anti-reflective film exhibits excellent anti-reflective performance. Furthermore, if the thickness of the titanium oxide film 1 is above the lower limit mentioned above, crystals in which a group of Ti2O3 diffraction spots appear in the electron diffraction pattern observed with a transmission electron microscope are more likely to grow, thereby increasing the refractive index of the titanium oxide film 1.

[0028] The surface roughness Ra (arithmetic mean surface roughness) of one side in the thickness direction of the titanium oxide film 1 is, for example, 0.5 nm or more, preferably 0.8 nm or more, and also, for example, 10 nm or less, preferably 8 nm or less.

[0029] When light with a wavelength of 550 nm is incident on the titanium oxide film 1, the total light transmittance is, for example, 75% or more, preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more. There is no upper limit to the total light transmittance of the titanium oxide film 1. For example, the upper limit to the total light transmittance of the titanium oxide film 1 is 100%.

[0030] 2. Laminate Next, one embodiment of the laminate will be described with reference to Figure 1.

[0031] As shown in Figure 1, the laminate X has a film shape (including a sheet shape) with a predetermined thickness. The laminate X extends in a plane direction perpendicular to the thickness direction, and one surface in the thickness direction and the other surface in the thickness direction of the laminate X are flat.

[0032] The laminate X comprises a base material 2 and a titanium oxide film 1, arranged sequentially on one side in the thickness direction. Specifically, as shown in Figure 1, the laminate X comprises a base material 2 and a titanium oxide film 1 disposed on one side of the base material 2 in the thickness direction.

[0033] <Base material> The base material 2 is the bottom layer of the laminate X. The base material 2 comprises a transparent resin film 21, a cured resin layer 22, and a protective layer 23 in order toward one side in the thickness direction. Specifically, the base material 2 comprises a transparent resin film 21, a cured resin layer 22 positioned on one side of the transparent resin film 21 in the thickness direction, and a protective layer 23 positioned on one side of the cured resin layer 22 in the thickness direction. More specifically, the base material 2 comprises, for example, a transparent resin film 21, a cured resin layer 22 positioned on one side of the transparent resin film 21 in the thickness direction, and a protective layer 23 positioned on one side of the cured resin layer 22 in the thickness direction.

[0034] The base material 2 preferably consists of a transparent resin film 21, a cured resin layer 22 disposed on one side of the transparent resin film 21 in the thickness direction, and a protective layer 23 disposed on one side of the cured resin layer 22 in the thickness direction. Specifically, the base material 2 preferably consists of a transparent resin film 21, a cured resin layer 22 disposed on one side of the transparent resin film 21 in the thickness direction, and a protective layer 23 disposed on one side of the cured resin layer 22 in the thickness direction.

[0035] The total light transmittance (JIS K-7105) when light with a wavelength of 550 nm is incident on the substrate 2 is, for example, 80% or more, preferably 85% or more, more preferably 88% or more, even more preferably 90% or more, and also, for example, 100% or less.

[0036] The thickness of the base material 2 is not particularly limited, but from the viewpoint of strength and handling, it is, for example, 10 μm or more, preferably 30 μm or more, more preferably 50 μm or more, and also, for example, 200 μm or less, preferably 150 μm or less, more preferably 100 μm or less.

[0037] The transparent resin film 21 is a transparent, flexible resin film. Examples of materials for the transparent resin film 21 include cellulose resin, polyester resin, (meth)acrylic resin (acrylic resin and / or methacrylic resin), olefin resin, polycarbonate resin, polyethersulfone resin, polyarylate resin, melamine resin, polyamide resin, polyimide resin, polystyrene resin, norbornene resin, and polyvinyl alcohol resin. Examples of polyester resins include polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate. Examples of polyolefin resins include polyethylene, polypropylene, and cycloolefin polymer (COP). Examples of cellulose resins include triacetylcellulose (TAC). The materials for the transparent resin film 21 can be used individually or in combination of two or more.

[0038] The transparent resin film 21 can be, for example, a cellulose resin film, from the viewpoint of transparency, heat resistance, and mechanical strength. Preferably, a triacetylcellulose (TAC) film is used.

[0039] The total light transmittance (JIS K-7105) when light with a wavelength of 550 nm is incident on the transparent resin film 21 is, for example, 80% or more, preferably 85% or more, more preferably 88% or more, even more preferably 90% or more, and also, for example, 100% or less.

[0040] The thickness of the transparent resin film 21 is not particularly limited, but from the viewpoint of strength and handling, for example, it is 5 μm or more, preferably 10 μm or more, more preferably 20 μm or more, even more preferably 30 μm or more, and particularly preferably 50 μm or more. Alternatively, for example, it is 300 μm or less, preferably 250 μm or less, more preferably 200 μm or less, even more preferably 170 μm or less, and particularly preferably 150 μm or less.

[0041] The thickness of the transparent resin film 21 can be measured, for example, using a film thickness gauge.

[0042] The cured resin layer 22 is a layer that improves the mechanical properties of the laminate X. The cured resin layer 22 is positioned on one side in the thickness direction of the transparent resin film 21 and on the other side in the thickness direction of the protective layer 23. Specifically, as shown in Figure 1, the cured resin layer 22 is positioned on one side in the thickness direction of the transparent resin film 21. In other words, the cured resin layer 22 is in contact with the transparent resin film 21.

[0043] Examples of the cured resin layer 22 include a hard coat layer and an anti-blocking layer. The hard coat layer, for example, makes it difficult for scratches to form on the exposed surface of the transparent resin film 21. The anti-blocking layer provides anti-blocking properties to the surfaces of multiple laminates X that come into contact with each other, for example, when laminates X are stacked in the thickness direction.

[0044] The cured resin layer 22 is, for example, a cured product of a curable resin composition. Specifically, the cured resin layer 22 can be formed by applying a curable resin composition to one side in the thickness direction of the transparent resin film 21, and then curing it after drying as necessary.

[0045] The curable resin composition contains a curable resin. Examples of curable resins include polyester resin, acrylic urethane resin, acrylic resin (excluding acrylic urethane resin), urethane resin (excluding acrylic urethane resin), amide resin, silicone resin, epoxy resin, and melamine resin. Acrylic urethane resin is preferred. The curable resin can be used alone or in combination of two or more types.

[0046] Furthermore, examples of curable resin compositions include ultraviolet-curable resin compositions and thermosetting resin compositions. From the viewpoint of manufacturing efficiency, ultraviolet-curable resin compositions are preferably used as curable resin compositions. A specific example of an ultraviolet-curable resin composition is the hard coat layer forming composition described in Japanese Patent Application Publication No. 2016-179686.

[0047] The curable resin composition may contain fine particles in the curable resin layer 22 from the viewpoint of adjusting hardness, surface roughness, refractive index, and providing anti-glare properties. Examples of fine particles include inorganic particles and organic particles. Inorganic particles are preferred. Examples of inorganic particles include inorganic oxide particles. Examples of materials for inorganic oxide particles include silica, alumina, titania, zirconia, calcium oxide, tin oxide, indium oxide, cadmium oxide, and antimony oxide. Silica is preferred. Examples of materials for organic particles include polymethyl methacrylate, polystyrene, polyurethane, acrylic-styrene copolymer, benzoguanamine, melamine, and polycarbonate.

[0048] The thickness of the cured resin layer 22 is, for example, 1 μm or more, preferably 2 μm or more, more preferably 5 μm or more, and also, for example, 15 μm or less, preferably 12 μm or less, more preferably 10 μm or less.

[0049] If the thickness of the cured resin layer 22 is greater than or equal to the lower limit mentioned above, the cured resin layer 22 can be easily formed and its functions can be fully expressed. Also, if the thickness of the cured resin layer 22 is less than or equal to the upper limit mentioned above, the laminate X can be made thinner.

[0050] One side of the cured resin layer 22 in the thickness direction may be surface-modified to improve adhesion with the protective layer 23. Examples of surface modification treatments include corona treatment, plasma treatment, flame treatment, ozone treatment, primer treatment, saponification treatment, and treatment with a coupling agent. Plasma treatment is preferred.

[0051] The protective layer 23 is a layer that prevents damage to the surface of the cured resin layer 22 when the titanium oxide film 1 is formed by HiPIMS, as described later, and improves the adhesion of the titanium oxide film 1 to the substrate 2.

[0052] The protective layer 23 is positioned on one side in the thickness direction of the cured resin layer 22 and on the other side in the thickness direction of the titanium oxide film 1. Specifically, as shown in Figure 1, the protective layer 23 is positioned on one side in the thickness direction of the cured resin layer 22. In other words, the protective layer 23 is in contact with the cured resin layer 22.

[0053] The protective layer 23 is a dry coating layer or a wet coating layer, preferably a dry coating layer, and more preferably a sputtered layer.

[0054] As for the material of the protective layer 23, in the case of a dry coating layer, an inorganic material can be used, and in the case of a wet coating layer, a mixture of an organic material and inorganic fine particles can be used.

[0055] Examples of inorganic materials include metals, alloys containing two or more metals, metalloids, and oxides thereof.

[0056] Examples of metals include nickel, chromium, indium, aluminum, tin, gold, silver, platinum, zinc, titanium, tungsten, zirconium, and palladium. Examples of metalloids include silicon. Examples of oxides include silicon-containing oxides, zinc-containing oxides, indium-containing oxides, and antimony-containing oxides. Examples of silicon-containing oxides include silicon oxide (SiO

[0060] , , )(0 < x ≤ 2). Examples of zinc-containing oxides include aluminum-zinc-silicon composite oxides (Al-Zn-SiO x ). Examples of indium-containing oxides include indium tin composite oxides (ITO), indium zinc composite oxides (IZO), indium gallium composite oxides (IGO), and indium gallium zinc composite oxides (IGZO). Examples of antimony-containing oxides include antimony tin composite oxides (ATO). The material of the protective layer 23 is preferably silicon and silicon oxide (SiO x )(0 < x ≤ 2). That is, the protective layer 23 is preferably a silicon layer and a silicon oxide layer.

[0057] Examples of the mixture of the organic material and the inorganic fine particles include a binder resin and inorganic fine particles dispersed in the binder resin.

[0058] Examples of the binder resin include cured products of ultraviolet curable resins. Examples of ultraviolet curable resins include epoxy resins, acrylic urethane resins, acrylic resins (excluding acrylic urethane resins), and urethane resins (excluding acrylic urethane resins).

[0059] Examples of the inorganic fine particles include fine particles of metal oxides. Examples of metal oxides include zirconium oxide, aluminum oxide, titanium oxide, and silicon oxide. <00002,18><00002,19><00002,20>The hardness (surface hardness H) of the surface of the protective layer 23 at 25°C, measured by nanoindentation, is, for example, 1.05 GPa or higher, preferably 1.1 GPa or higher, more preferably 1.15 GPa or higher, and also, for example, 30 GPa or lower, preferably 20 GPa or lower, more preferably 15 GPa or lower. If the surface hardness H is within the above upper and lower limits, the titanium oxide film 1 is formed without damaging the surface of the cured resin layer 22 by HiPIMS described later, and the adhesion of the titanium oxide film 1 to the substrate 2 is improved.

[0061] The nanoindentation method will be carried out in accordance with ISO 14577. Furthermore, the same method as in Examples 1 to 4 of Japanese Patent Publication No. 2023-013412 will be employed.

[0062] The thickness of the protective layer 23 is, for example, 20 nm or more, preferably 30 nm or more, more preferably 40 nm or more, even more preferably 50 nm or more, and also, for example, 100 nm or less, preferably 90 nm or less, more preferably 80 nm or less, even more preferably 70 nm or less.

[0063] If the thickness of the protective layer 23 is greater than or equal to the lower limit described above, the titanium oxide film 1 is formed without damaging the surface of the cured resin layer 22 by HiPIMS described later, and the adhesion of the titanium oxide film 1 to the substrate 2 is improved. Also, if the thickness of the protective layer 23 is less than or equal to the upper limit described above, the laminate X becomes thinner.

[0064] The thickness of the laminate X is, for example, 20 μm or more, preferably 30 μm or more, more preferably 50 μm or more, even more preferably 60 μm or more, and also, for example, 200 μm or less, preferably 180 μm or less, more preferably 150 μm or less, and even more preferably 100 μm or less.

[0065] When light with a wavelength of 550 nm is incident on the laminate X, the total light transmittance is, for example, 80% or more, preferably 85% or more, more preferably 88% or more, even more preferably 90% or more, and also, for example, 100% or less.

[0066] <Application> The laminate described above can be applied to anti-reflective films used, for example, in electronic equipment casings, vehicle components, home appliance casings, structural components, machine components, various automotive parts, electronic equipment components, furniture, kitchenware, and the like.

[0067] 3. Method for producing titanium oxide film Referring to Figures 2A and 2B, one embodiment of the method for manufacturing the laminate will be described. In this embodiment, the method for manufacturing the titanium oxide film 1 is one step in the method for manufacturing the laminate X.

[0068] A method for manufacturing the laminate X includes, for example, a first step of preparing a substrate 2 (Figure 2A) and a second step of forming a titanium oxide film 1 on one side of the substrate 2 in the thickness direction (method for manufacturing the titanium oxide film 1) (Figure 2B).

[0069] <1st process> In the first step, the base material 2 is prepared as shown in Figure 2A.

[0070] To prepare the base material 2, a transparent resin film 21 is prepared, a cured resin layer 22 is formed on one side in the thickness direction of the transparent resin film 21, and then a protective layer 23 is formed on one side in the thickness direction of the cured resin layer 22.

[0071] To form the cured resin layer 22, the above-mentioned curable resin composition is applied to one side in the thickness direction of the transparent resin film 21 to form a coating film, and then this coating film is cured.

[0072] The curable resin composition may further contain a photopolymerization initiator, a leveling agent, and a solvent (diluent).

[0073] If the curable resin composition contains a solvent, the coating on the transparent resin film 21 is dried after the curable resin composition is applied.

[0074] The drying temperature is, for example, 50°C to 120°C. The drying time is, for example, 10 seconds to 10 minutes.

[0075] When the curable resin composition includes an ultraviolet-curable resin, the coating on the transparent resin film 21 is cured by ultraviolet irradiation. Examples of ultraviolet irradiation light sources include high-pressure mercury lamps and LED lights. Preferably, a high-pressure mercury lamp is used. The cumulative amount of ultraviolet irradiation is, for example, 100 mJ / cm². 2 ~500mJ / cm 2 That is the case.

[0076] Methods for forming the protective layer 23 include dry coating and wet coating. Examples of dry coating methods include vacuum deposition, sputtering, and ion plating. Sputtering is preferred. Examples of wet coating methods include gravure coating, reverse coating, and die coating.

[0077] Examples of sputtering methods include two-electrode sputtering, ECR (electron cyclotron resonance) sputtering, magnetron sputtering, and ion beam sputtering. Preferably, reactive sputtering using the magnetron sputtering method is used.

[0078] The protective layer 23 is formed using a sputtering deposition apparatus capable of performing the deposition process in a roll-to-roll manner. When a roll-to-roll sputtering deposition apparatus is used to form the protective layer 23, the work film W (transparent resin film 21 with a cured resin layer 22) travels from the feed roll to the winding roll of the sputtering deposition apparatus, and the material for the protective layer 23 is deposited on one side in the thickness direction of the cured resin layer 22, thereby forming the protective layer 23. The travel speed of the work film W (transparent resin film 21 with a cured resin layer 22) is, for example, 0.1 to 10.0 m / min.

[0079] In the sputtering method, specifically, a sputtering gas is introduced into the deposition chamber under vacuum conditions, and a negative voltage is applied to a target made of the protective layer 23 material described above within the deposition chamber. This generates a glow discharge, ionizing the gas atoms, which then collide with the target surface at high speed, ejecting the target material from the target surface. The ejected target material is then deposited on one side in the thickness direction of the work film W (a transparent resin film 21 with a cured resin layer 22). The target is made of the protective layer 23 material described above, preferably silicon.

[0080] Examples of sputtering gases include inert gases and reactive gases. Examples of inert gases include argon, krypton, xenon, and mixtures thereof, with argon being preferred. Examples of reactive gases include oxygen. In reactive sputtering, for example, oxygen is introduced into the deposition chamber in addition to the inert gas. That is, the protective layer 23 is deposited in the presence of an inert gas and / or oxygen.

[0081] The achievable vacuum level in the deposition chamber is, for example, 1.0 × 10⁻⁶. -4 It is below Pa.

[0082] When introducing an inert gas and oxygen into the film deposition chamber, the volume ratio of oxygen to the total volume of the inert gas and oxygen is, for example, 0.1% to 50% by volume, preferably 1% to 40% by volume, more preferably 5% to 30% by volume, and even more preferably 10% to 25% by volume.

[0083] The atmospheric pressure inside the deposition chamber (the atmospheric pressure inside the deposition chamber when an inert gas and / or oxygen is introduced) is, for example, 0.01 Pa to 5.0 Pa, preferably 0.05 Pa to 3.0 Pa, more preferably 0.10 Pa to 1.0 Pa, and even more preferably 0.15 Pa to 0.80 Pa.

[0084] The film formation temperature (the temperature of the roll supporting the transparent resin film 21 having the cured resin layer 22) is, for example, room temperature.

[0085] Examples of power supplies for applying voltage to the target include DC power supplies, AC power supplies, MF power supplies, and RF power supplies. An MFAC power supply, which combines an MF power supply and an AC power supply, may also be used. Preferably, an MFAC power supply is used.

[0086] The discharge power is, for example, 0.1kW to 10kW, preferably 1kW to 5kW.

[0087] In the wet coating method, a coating liquid (varnish) containing the material for the protective layer 23 is applied to one side in the thickness direction of the cured resin layer 22 to form a coating film, and then the protective layer 23 is formed by drying and curing this coating film. The material for the protective layer 23 may be a mixture of organic material and inorganic fine particles, and more specifically, a binder resin and inorganic fine particles dispersed in the binder resin.

[0088] The drying temperature is, for example, 60°C to 120°C. The drying time is, for example, 10 to 60 minutes.

[0089] The dried coating hardens upon exposure to ultraviolet (UV) light. Examples of UV light sources include high-pressure mercury lamps and LED lights. High-pressure mercury lamps are preferred. The cumulative UV irradiation dose is, for example, 100 mJ / cm². 2 ~500mJ / cm 2 That is the case.

[0090] In this manner, the base material 2 is prepared.

[0091] By forming a protective layer 23 on one side in the thickness direction of the cured resin layer 22, the titanium oxide film 1 can be formed without damaging the surface of the cured resin layer 22 using HiPIMS, as described later, and the adhesion of the titanium oxide film 1 to the substrate 2 is improved.

[0092] Furthermore, before forming the protective layer 23, one side of the cured resin layer 22 in the thickness direction may be plasma-treated. A roll-to-roll sputtering deposition apparatus can be used for the plasma treatment. In other words, the plasma treatment and the formation of the protective layer 23 can be carried out continuously.

[0093] Examples of plasma treatments include plasma treatment by glow discharge, plasma treatment by a low-inductance antenna, and plasma treatment by atmospheric pressure plasma. Plasma treatment by glow discharge is preferred. The following conditions can be adjusted as appropriate depending on the plasma treatment method.

[0094] Specifically, under vacuum conditions, an inert gas and / or a reactive gas are introduced into the plasma processing chamber of the sputtering deposition apparatus, and a voltage is applied to generate plasma, thereby plasma-treating one side of the cured resin layer 22 in the thickness direction.

[0095] Examples of inert gases used in plasma processing include nitrogen, argon, krypton, xenon, and mixtures thereof. Examples of reactive gases used in plasma processing include oxygen.

[0096] The achievable vacuum degree in the plasma processing chamber is, for example, 1.0×10 -4 Pa or less.

[0097] The atmospheric pressure in the plasma processing chamber (the atmospheric pressure in the plasma processing chamber when introducing an inert gas and / or oxygen) is, for example, 0.01 Pa to 5.0 Pa, preferably 0.05 Pa to 3.0 Pa, more preferably 0.10 Pa to 1.0 Pa, and even more preferably 0.15 Pa to 0.80 Pa.

[0098] The discharge power in the plasma processing chamber is, for example, 0.01 kW to 10 kW, preferably 0.05 kW to 5 kW.

[0099] <Second Step> In the second step, as shown in FIG. 2B, the titanium oxide film 1 is formed on one surface in the thickness direction of the substrate 2 (one surface in the thickness direction of the protective layer 23).

[0100] Examples of the method for forming the titanium oxide film 1 include the dry coating method. Examples of the dry coating method include, for example, the vacuum evaporation method, the sputtering method, and the ion plating method. Preferably, the sputtering method is included.

[0101] Examples of the sputtering method include, for example, the two - pole sputtering method, the ECR (electron cyclotron resonance) sputtering method, the magnetron sputtering method, and the ion beam sputtering method. Preferably, reactive sputtering by the magnetron sputtering method is included.

[0102] In the second step, a sputtering film - forming apparatus capable of implementing the film - forming process in a roll - to - roll manner is used. In the second step, when a roll - to - roll type sputtering film - forming apparatus is used, the work film W (substrate 2) travels from the feed roll provided in the sputtering film - forming apparatus to the take - up roll, and the titanium oxide film 1 is formed on one surface in the thickness direction of the protective layer 23. The traveling speed of the work film W (substrate 2) is, for example, 0.1 to 10.0 m / min.

[0103] In the sputtering method, specifically, a sputtering gas is introduced into the deposition chamber of a sputtering deposition apparatus under vacuum conditions, while a negative voltage is applied to the target inside the chamber. This generates a glow discharge, ionizing the gas atoms, which then collide with the target surface at high speed, ejecting the target material from the surface and depositing it in the thickness direction. Titanium (Ti) is used as the target.

[0104] Examples of sputtering gases include inert gases and reactive gases. Examples of inert gases include argon, krypton, xenon, and mixtures thereof, with argon being preferred. Examples of reactive gases include oxygen. In the reactive sputtering method, for example, oxygen is introduced into the deposition chamber in addition to the inert gas. In other words, the titanium oxide film 1 is deposited in the presence of an inert gas and oxygen.

[0105] The volume ratio of oxygen to the total volume of inert gas and oxygen introduced into the film deposition chamber is, for example, 0.01% to 30% by volume, preferably 0.1% to 20% by volume, more preferably 1% to 10% by volume, and even more preferably 2% to 5% by volume.

[0106] The vacuum level achieved in the deposition chamber before sputter deposition, and the atmospheric pressure in the deposition chamber (atmospheric pressure in the deposition chamber when inert gas and / or oxygen are introduced) are the same as in the case of forming the protective layer 23 described above.

[0107] The film formation temperature (temperature of the roll supporting the substrate 2) is 70°C or higher, preferably 80°C or higher, more preferably 100°C or higher, and also 130°C or lower, preferably 120°C or lower, more preferably 110°C or lower.

[0108] If the deposition temperature is above the lower limit mentioned above, the refractive index of the titanium oxide film 1 will increase. Furthermore, the titanium oxide film 1 will be deposited containing crystals in which a group of Ti2O3 diffraction spots appears in the electron diffraction pattern observed with a transmission electron microscope.

[0109] In the second step, high-power impulse magnetron sputtering (HiPIMS) is used as the power source for applying voltage to the target.

[0110] In HiPIMS, specifically, a voltage is applied to the target at a predetermined frequency and pulse width, generating a high-density plasma. This high-density plasma ionizes gas atoms, and the gas ions collide with the target surface at high speed, ejecting the target material from the surface. This ejected target material is then deposited in the thickness direction.

[0111] In the second step, the titanium oxide film 1 is formed using HiPIMS, resulting in the formation of a titanium oxide film 1 containing crystals that show a group of Ti2O3 diffraction spots in the electron diffraction pattern observed with a transmission electron microscope, and also increasing the film formation rate of the titanium oxide film 1. Furthermore, the titanium oxide film 1 is formed without damaging the surface of the cured resin layer 22, improving the adhesion of the titanium oxide film 1 to the substrate 2.

[0112] When using HiPIMS, the discharge voltage is, for example, 1000V to 2000V, preferably 1500V to 1800V.

[0113] When using HiPIMS, the frequency is, for example, 150Hz to 300Hz, preferably 200Hz to 250Hz.

[0114] When using HiPIMS, the pulse width is, for example, 10 μs to 100 μs, preferably 20 μs to 50 μs.

[0115] As described above, a titanium oxide film 1 is formed on one side of the protective layer 23 in the thickness direction.

[0116] In this manner, the laminate X is manufactured.

[0117] 4. Variations <Example of a laminated structure> In Figure 1, the substrate 2 consists of a transparent resin film 21, a cured resin layer 22 disposed on one side of the transparent resin film 21 in the thickness direction, and a protective layer 23 disposed on one side of the cured resin layer 22 in the thickness direction, but is not limited to this.

[0118] In other words, the base material 2 may consist only of the transparent resin film 21. Alternatively, the base material 2 may consist of the transparent resin film 21 and a protective layer 23 disposed on one side of the transparent resin film 21 in the thickness direction. Furthermore, the cured resin layer 22 may be disposed on both sides of the transparent resin film 21, one side and the other side in the thickness direction.

[0119] <Effects and Effects> The titanium oxide film produced by the above method contains crystals in which a group of Ti2O3 diffraction spots appear in the electron diffraction pattern observed with a transmission electron microscope, and its refractive index when incident with light of a wavelength of 550 nm is greater than 2.50 and less than or equal to 2.80. Therefore, when the titanium oxide film is used as an anti-reflective film, the anti-reflective film has excellent anti-reflective performance, and the titanium oxide film does not require annealing at high temperatures of 600°C or higher for a long time, unlike rutile-type TiO2 films, and has a high film deposition rate, resulting in excellent manufacturing efficiency for the titanium oxide film. [Examples]

[0120] The present invention will be further described below with reference to examples, comparative examples, and reference examples. However, the present invention is not limited to the examples, comparative examples, and reference examples. Furthermore, specific numerical values ​​such as blending ratios (content ratios), physical properties, and parameters used in the following description may be replaced with the upper limits (numerical values ​​defined as "less than or equal to" or "less than") or lower limits (numerical values ​​defined as "greater than or equal to" or "greater than") of the corresponding blending ratios (content ratios), physical properties, and parameters described in the "Modes for Carrying Out the Invention" above.

[0121] <Fabrication of titanium oxide films> Example 1 As shown below, the titanium oxide film of Example 1 was prepared.

[0122] [1st step] A mixture was prepared by mixing 100 parts by mass of a butyl acetate solution of UV-curable acrylic urethane resin (product name: Luxidia 17-806, solids content: 80% by mass, manufactured by DIC Corporation), 5 parts by mass of a photopolymerization initiator (product name: IRGACURE 906, manufactured by BASF Corporation), and 0.01 parts by mass of a leveling agent (product name: GRANDIC PC4100, manufactured by DIC Corporation). Subsequently, the solids content of the mixture was adjusted to 36% by mass by adding a mixed solvent of cyclopentanone (CPN) and propylene glycol monomethyl ether (PGM) (mass ratio of CPN to PGM: 45:55) to obtain a curable resin composition. This curable resin composition was applied to one side in the thickness direction of an 80 μm thick triacetylcellulose (TAC) film (product name: KC8UA, manufactured by Konica Minolta Advanced Layer Corporation) so that the thickness after drying was 7 μm, and it was dried at 90°C for 1 minute. Subsequently, a high-pressure mercury lamp was used to obtain a wavelength of 365 nm and an integrated light intensity of 300 mJ / cm². 2 The coated layer was cured by irradiation with ultraviolet light to form a cured resin layer. In this way, a TAC film (substrate) having a cured resin layer was obtained.

[0123] Next, a 60 nm thick silicon layer (protective layer) was formed on one side in the thickness direction of the cured resin layer. A roll-to-roll magnetron sputter deposition apparatus was used to form the silicon layer (protective layer). The sputter deposition apparatus is equipped with a deposition chamber that allows the deposition process to be carried out while the work film is moved in a roll-to-roll manner. In the deposition of the silicon layer (protective layer), the achievable vacuum level in the deposition chamber of the sputter deposition apparatus was 1.0 × 10⁻⁶. -4After evacuating the chamber to a vacuum of 0.2 Pa, argon was introduced as an inert gas into the deposition chamber to set the atmospheric pressure to 0.2 Pa. Silicon was used as the target. An MFAC power supply was used to apply voltage to the target, with a discharge power of 3.0 kW, and the deposition temperature (temperature of the roll supporting the work film) was set to room temperature. In this way, a silicon layer (protective layer) was formed on one side in the thickness direction of the cured resin layer. The substrate was prepared in this manner.

[0124] [Second process] Next, a 50 nm thick titanium oxide film was formed on one side of the silicon layer (protective layer) in the thickness direction. A roll-to-roll magnetron sputtering deposition system was used to form the titanium oxide film. The sputtering deposition system is equipped with a deposition chamber that allows the deposition process to be carried out while the work film is moved in a roll-to-roll manner. In the deposition of the titanium oxide film, the achievable vacuum level in the deposition chamber of the sputtering deposition system was 1.0 × 10⁻⁶. -4 After evacuating the chamber to a pressure of Pa, argon as an inert gas and oxygen as a reactive gas were introduced into the deposition chamber to set the atmospheric pressure to 0.2 Pa. The argon and oxygen were introduced into the chamber in a volume ratio of 100:5. Titanium was used as the target. A HiPIMS (product name: TruPlasma Highpulse 4002 G2, manufactured by Trumpf) was used as the power supply for applying voltage to the target, with a discharge voltage of 1700V, a frequency of 210Hz, and a pulse width of 35μs. The deposition temperature (temperature of the roll supporting the work film) was set to 100℃. In the second step, the deposition time was determined by dividing the length of the roll opening (the part of the roll exposed to the plasma in the sputter deposition apparatus) by the running speed of the work film. In this way, a titanium oxide film was formed on one side in the thickness direction of the silicon layer (protective layer).

[0125] Example 2 The titanium oxide film of Example 2 was fabricated in the same manner as the titanium oxide film of Example 1, except that when forming the protective layer, argon as an inert gas and oxygen as a reactive gas were introduced into the deposition chamber, with the volume ratio of argon to oxygen being 100:30.

[0126] Example 3 In the second step, the titanium oxide film of Example 3 was prepared in the same manner as the titanium oxide film of Example 1, except that the film deposition temperature was set to 70°C.

[0127] Comparative Example 1 The procedure was carried out in the same manner as in Example 1, except that a protective layer was not formed.

[0128] Comparative Example 2 In the second step, argon and oxygen were introduced into the deposition chamber in a volume ratio of 100:10. A DC power supply was used as the power source for applying voltage to the target, and the discharge power was set to 3.0 kW. Except for these conditions, the titanium oxide film of Comparative Example 2 was fabricated in the same manner as the titanium oxide film of Example 1.

[0129] Comparative Example 3 In the second step, the titanium oxide film of Comparative Example 3 was prepared in the same manner as the titanium oxide film of Example 1, except that the film deposition temperature was set to room temperature.

[0130] Comparative Example 4 In the first step, alkali-free glass was prepared instead of a TAC film with a cured resin layer, and no protective layer was formed. In the second step, a batch-type magnetron sputtering deposition apparatus was used to form the titanium oxide film, and the deposition temperature was set to room temperature. Except for these differences, the titanium oxide film of Comparative Example 4 was prepared in the same manner as the titanium oxide film of Example 1.

[0131] <Measuring refractive index> The titanium oxide films obtained in each example and comparative example were measured using a spectroscopic ellipsometer (product name: RC2, JAWoollam Japan). After measurement, the refractive index was determined by fitting the measured spectra with the polarization analysis parameters ψ and Δ to the simulation spectra calculated from the optical model. As the optical model, a layered structure consisting of a film, a protective layer, and a titanium oxide film was set, and the titanium oxide film was fitted using Cauchy's dispersion formula. The results are shown in Table 1.

[0132] <Analysis of electron diffraction patterns> For the titanium oxide films obtained in each example and comparative example, cross-sections were prepared at specified locations using FIB microsampling, and the cross-sections were observed using FE-TEM (product name: JEM-2800, JEOL). After obtaining electron diffraction patterns from the cross-sections of the titanium oxide films, the constituent layers of the titanium oxide films were analyzed from the interplanar spacing of the electron diffraction spots and the interplanar spacing on the ICDD data. The results are shown in Table 1.

[0133] <Calculation of film deposition rate> For each example and comparative example, the thickness of the titanium oxide film obtained was determined by cross-sectional observation using FE-TEM, and the deposition rate was calculated by dividing this by the deposition time described above. The results are shown in Table 1.

[0134] [Table 1] [Explanation of Symbols]

[0135] 1. Titanium oxide film 2 Base material 21 Transparent resin film 22 Cured resin layer 23 Protective layer X-layer

Claims

1. In the electron diffraction pattern observed with a transmission electron microscope, Ti ２ O ３ The crystal contains the diffraction spot group that appears, A titanium oxide film whose refractive index, when incident on light with a wavelength of 550 nm, is greater than 2.50 and less than or equal to 2.

80.

2. The titanium oxide film according to claim 1, wherein the refractive index is greater than 2.

68.

3. The method for producing a titanium oxide film according to claim 1, A method for producing a titanium oxide film, comprising the step of forming the titanium oxide film on one side of the thickness direction of a substrate using high-power impulse magnetron sputtering (HiPIMS) at a film formation temperature of 70°C or higher.

4. A method for producing a titanium oxide film according to claim 3, wherein the above-mentioned step is carried out with the film formation temperature set to 100°C or higher.

5. The method for producing a titanium oxide film according to claim 3 or 4, wherein the above step is carried out by a roll-to-roll method.

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