Method for manufacturing optical laminates

Abstract

To provide a method for manufacturing optical laminates that can stably produce optical laminates having a desired dimensional ratio. [Solution] A method for manufacturing an optical laminate according to an embodiment of the present invention includes: a transport step of transporting a long film including a first optical film; and a bonding step of bonding a second optical film having a sheet shape to the first optical film via an adhesive layer composed of a curing adhesive.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an optical laminate.

Background Art

[0002] In recent years, image display devices typified by liquid crystal display devices and electroluminescent (EL) display devices (for example, organic EL display devices, inorganic EL display devices) have been rapidly spreading. In many cases, an optical laminate including a polarizing plate and / or a retardation film is used in an image display device. The optical laminate can be produced by conveying a plurality of predetermined long optical films and laminating them with each other through an adhesive layer composed of a curable adhesive in a roll-to-roll manner (for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in an optical laminate produced by conveying a long optical film and laminating it through an adhesive layer composed of a curable adhesive in a roll-to-roll manner, the dimensional ratio between the dimension in the conveying direction (MD direction) and the dimension in the direction orthogonal to the conveying direction (TD direction) may deviate from a desired value.

[0005] The main object of the present invention is to provide a method for manufacturing an optical laminate that can stably manufacture an optical laminate having a desired dimensional ratio.

Means for Solving the Problems

[0006] [1] A method for manufacturing an optical laminate according to an embodiment of the present invention includes: a transport step of transporting a long film including a first optical film; and a bonding step of bonding a second optical film having a single sheet shape to the first optical film via an adhesive layer composed of a curing adhesive. [2] In the manufacturing method described in [1] above, in the bonding step, a plurality of the second optical films are bonded to the first optical film such that they are spaced apart from each other in the longitudinal direction of the long film. [3] In the manufacturing method described in [1] or [2] above, in the bonding step, the plurality of second optical films are transported by a carrier film and supplied to the first optical film. [4] In the manufacturing method described in any of [1] to [3] above, the long film includes a first optical film having a long shape. [5] In the manufacturing method described in any of [1] to [4] above, the long film comprises a base film having a long shape and a plurality of first optical films having a sheet shape, wherein the plurality of first optical films are positioned on the base film at intervals from each other in the longitudinal direction of the base film; and in the bonding step, each of the plurality of second optical films is bonded to each of the plurality of first optical films. [6] In the manufacturing method described in any of [1] to [5] above, the first optical film comprises a first surface film that contacts the adhesive layer in the bonding step; the second optical film comprises a second surface film that contacts the adhesive layer in the bonding step; the thickness of the adhesive layer is 2 μm or less; and the thickness of at least one of the first surface film and the second surface film is 2 μm or less. [7] In the manufacturing method described in [6] above, the thickness of the first surface film and the second surface film is 3 μm or less. [8] In the manufacturing method described in [6] or [7] above, at least one of the first surface film and the second surface film is an orientation solidified layer of liquid crystal compound. [9] In the manufacturing method described in any of [6] to [8] above, the second surface film is an oriented solidified layer of liquid crystal compound and functions as a λ / 4 plate.

[10] In the manufacturing method described in any of [6] to [9] above, the first surface film is an orientation solidified layer of liquid crystal compound and functions as a λ / 2 plate.

[11] In the manufacturing method described in any of [1] to

[10] above, the first optical film includes a polarizer. [Effects of the Invention]

[0007] According to embodiments of the present invention, optical laminates having a desired dimensional ratio can be stably manufactured. [Brief explanation of the drawing]

[0008] [Figure 1A] This is a schematic side view showing a method for manufacturing an optical laminate according to one embodiment (first embodiment) of the present invention. [Figure 1B] This is a schematic plan view showing a part of the manufacturing method for an optical laminate according to the first embodiment. [Figure 1C] This is a schematic cross-sectional view of an optical laminate that can be obtained by the method for manufacturing an optical laminate according to the first embodiment. [Figure 1D] This is a schematic cross-sectional view showing one specific example of an optical laminate obtained by the method for manufacturing an optical laminate according to the first embodiment. [Figure 1E] This is a schematic cross-sectional view showing one specific example of an optical laminate obtained by the method for manufacturing an optical laminate according to the first embodiment. [Figure 1F] This is a schematic cross-sectional view showing one specific example of an optical laminate obtained by the method for manufacturing an optical laminate according to the first embodiment. [Figure 2A] This is a schematic side view showing a method for manufacturing an optical laminate according to another embodiment (second embodiment) of the present invention. [Figure 2B] This is a schematic cross-sectional view of an optical laminate that can be obtained by the method for manufacturing an optical laminate according to the second embodiment. [Figure 3A]It is a schematic side view showing a method for manufacturing an optical laminate according to another embodiment (third embodiment) of the present invention. [Figure 3B] It is a schematic cross-sectional view of an optical laminate that can be obtained by the method for manufacturing an optical laminate according to the third embodiment. [Figure 4] It is a schematic cross-sectional view of an optical laminate that can be obtained by the method for manufacturing an optical laminate according to the fourth embodiment.

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. The drawings are schematically drawn for ease of viewing, and the thickness, length, width, shape, ratio, etc. do not accurately reflect the actual shape.

[0010] (Definitions of Terms and Symbols) The definitions of the terms and symbols in this specification are as follows. (1) Refractive Index (nx, ny, nz) "nx" is the refractive index in the direction in which the in-plane refractive index is maximum (i.e., the slow axis direction), "ny" is the refractive index in the direction orthogonal to the slow axis in the plane (i.e., the fast axis direction), "n z" is the refractive index in the thickness direction. (2) In-Plane Phase Difference (Re) "Re(λ)" is the in-plane phase difference of the film measured with light of wavelength λ nm at 23°C There is. For example, "Re(550)" is the in-plane phase difference of the film measured with light of wavelength 550 nm at 23°C Is the in-plane phase difference of the film. Re(λ) is, when the thickness of the film is d (nm), the formula : Re = (nx - ny) × d. (3) Phase Difference in the Thickness Direction (Rth) "Rth(λ)" is the phase difference in the thickness direction of the film measured with light of wavelength λ nm at 23°C Is the phase difference. For example, "Rth(550)" is the light of wavelength 550 nm at 23°C This is the phase difference in the thickness direction of the measured film. Rth(λ) is the film thickness d(n When m is given, it can be found by the formula: Rth = (nx - nz) × d. (4)Angle In this specification, when angles are mentioned, unless otherwise specified, those angles are clockwise. It encompasses angles in both clockwise and counterclockwise directions. Therefore, for example, "45°" is ±45 ° is included.

[0011] A. Overview of the manufacturing method for optical laminates First, an outline of the method for manufacturing an optical laminate according to an embodiment of the present invention will be described. The method for manufacturing an optical laminate according to this embodiment includes: a transport step of transporting a long film including a first optical film; and a bonding step of attaching a second optical film having a single-sheet shape to the first optical film via an adhesive layer composed of a curing adhesive. The long film has a long shape. In this specification, "long shape" means an elongated shape in which the length is sufficiently longer than the width, and for example, includes an elongated shape in which the length is 10 times or more, preferably 20 times or more, than the width. Hereinafter, the length direction of the long film will simply be referred to as the "long direction," and the direction perpendicular to both the long direction and the thickness direction of the long film will simply be referred to as the "width direction."

[0012] The inventors of the present invention were investigating a method for manufacturing long optical laminates by conveying long roll-shaped optical films (including laminates) and bonding them together using a curable adhesive via a roll-to-roll method, and then curing the adhesive. They discovered that the dimensional ratio of the length direction to the width direction of the resulting optical laminate sometimes deviates from the desired value. Roll-to-roll is a method of continuously bonding long films together while conveying them on a roll and aligning their length directions.

[0013] As a result of diligent research, the inventors have found that the above-mentioned deviation in dimensional ratio is caused by the use of a curable adhesive when transporting a long film during the manufacturing of the optical laminate. More specifically, since tension due to transport (transport tension) acts in the transport direction of the optical film, the curable adhesive may shrink more significantly in the width direction than in the transport direction (length direction) during curing. When anisotropy occurs in the curing shrinkage of the curable adhesive in this way, thickness variations occur in the adhesive layer composed of the curable adhesive, causing a deviation in the dimensional ratio between the length and width directions of the optical laminate, and potentially preventing the optical laminate from stably exhibiting the desired performance. In particular, when an optical laminate includes a phase difference film (for example, an orientation solidified layer of a liquid crystal compound (hereinafter referred to as the liquid crystal orientation solidified layer)) as an optical film, if there are thickness variations in the adhesive layer of the optical laminate, certain display irregularities (interference irregularities) may become noticeable in the image display device to which the optical laminate is applied, depending on the viewing environment.

[0014] In the method for manufacturing an optical laminate according to an embodiment of the present invention, a sheet-like second optical film is attached to the first optical film using a curable adhesive while a long film containing the first optical film is being transported. This suppresses the effect of tension caused by the transport of the long film on the second optical film and the curable adhesive. As a result, the curable adhesive can be cured and shrunk isotropically. Consequently, an optical laminate having a desired dimensional ratio can be stably manufactured.

[0015] Furthermore, in such optical laminates, the curing adhesive undergoes isotropic curing shrinkage, which reduces thickness variations in the adhesive layer. Therefore, when an optical laminate including a phase difference film is applied to an image display device, linear interference variations can be suppressed.

[0016] Figure 1A is a schematic side view showing a method for manufacturing an optical laminate according to one embodiment of the present invention, and Figure 1B is a schematic plan view showing a part of the method for manufacturing an optical laminate according to the above embodiment. Figure 1C is a schematic cross-sectional view showing a part of an optical laminate that can be manufactured according to this embodiment. The method for manufacturing an optical laminate shown in the illustration includes a transport step of transporting a long film 100 including a first optical film 10; and a bonding step of bonding a second optical film 20 having a sheet-like shape to the first optical film via an adhesive layer 30 made of a curable adhesive. In the method for manufacturing an optical laminate according to the above embodiment, preferably, in the bonding step, a plurality of second optical films 20 are bonded to the first optical film 10 so that they are spaced apart from each other in the longitudinal direction of the long film 100. With such a configuration, an optical laminate having a desired dimensional ratio can be efficiently manufactured.

[0017] The optical laminates that can be obtained according to embodiments of the present invention may be elongated or sheet-shaped. The elongated optical laminate can be wound into a roll. "Sheet-shaped" means a shape that is not elongated but cut to any appropriate size. A sheet-shaped optical laminate can be manufactured, for example, by cutting an elongated optical laminate to a predetermined size (typically a size corresponding to an image display device).

[0018] Next, the elements that make up the optical laminate will be explained in detail with reference to the drawings.

[0019] B. Long film The long film 100 can be wound into a roll, for example. The width dimension and the length dimension of the long film can each have any suitable dimensions. The width dimension of the long film is, for example, 500 mm or more and 2000 mm or less, preferably 1000 mm or more and 1500 mm or less. The length dimension of the long film is, for example, 100 m or more and 5000 m or less, preferably 1000 m or more and 4000 m or less. Note that the length dimension of the long film is the dimension of the longest film (layer) in the length direction among the layers that the long film may contain.

[0020] The long film 100 includes the first optical film 10. The long film may include only the first optical film, or it may include the first optical film plus other films.

[0021] B-1. First Optical Film The first optical film can be any optical film having suitable optical properties, insofar as the desired properties of the optical laminate are obtained. The optical films that can constitute the first optical film may have a single-layer structure or a laminated structure. Examples of optical films include polarizing plates and phase difference films. The optical film may include these individually or in combination.

[0022] As shown in Figure 1D, in one embodiment, the first optical film 10 includes a phase difference film 120a.

[0023] B-1-1. Phase difference film The phase difference film may have any suitable optical and / or mechanical properties depending on the purpose. Regarding the optical properties, any suitable properties may be adopted depending on the desired purpose of the optical laminate that can be manufactured by the manufacturing method according to the embodiments of the present invention. Phase difference films typically have a slow phase axis. The in-plane phase difference Re(550) of the phase difference film is, for example, 100 nm to 300 nm. The Nz coefficient of the phase difference film is, for example, 0.9 to 1.5, preferably 0.9 to 1.3. The phase difference film may function as a λ / 2 plate or as a λ / 4 plate. In one embodiment, the phase difference film provided in the first optical film functions as a λ / 2 plate. When the phase difference film functions as a λ / 2 plate, the in-plane phase difference Re(550) of the phase difference film is preferably 200 nm to 300 nm, more preferably 230 nm to 290 nm, and even more preferably 250 nm to 280 nm.

[0024] The phase difference film may exhibit inverse dispersion wavelength characteristics in which the phase difference value increases with the wavelength of the measured light, or it may exhibit positive wavelength dispersion characteristics in which the phase difference value decreases with the wavelength of the measured light, or it may exhibit flat wavelength dispersion characteristics in which the phase difference value hardly changes with the wavelength of the measured light.

[0025] The phase difference film includes, for example, a stretched resin film and / or a liquid crystal alignment solidification layer.

[0026] <Resin film (stretched film)> Typical resins that make up resin films include polycarbonate resins, polyester carbonate resins, polyester resins, polyvinyl acetal resins, polyarylate resins, cyclic olefin resins, cellulose resins, polyvinyl alcohol resins, polyamide resins, polyimide resins, polyether resins, polystyrene resins, and acrylic resins. These resins may be used individually or in combination (for example, blended or copolymerized).

[0027] <Liquid crystal alignment solidification layer> A "liquid crystal alignment solidification layer" specifically refers to a layer in which liquid crystal compounds are oriented in a predetermined direction within the layer, and this orientation state is fixed. The concept of a "liquid crystal alignment solidification layer" encompasses the orientation-cured layer obtained by curing liquid crystal monomers. As described above, since the birefringence (Δn) of the liquid crystal alignment solidification layer (liquid crystal compound) is significantly larger than that of resin, using a liquid crystal alignment solidification layer makes it possible to significantly reduce the thickness required to obtain the desired in-plane phase difference compared to a stretched resin film. Therefore, it becomes possible to make the liquid crystal alignment solidification layer and optical laminate even thinner, which can ultimately contribute to the significant thinning of films (typically phase difference films, etc.) and devices (typically image display devices, etc.) to which the optical laminate is applied.

[0028] Examples of liquid crystal compounds used in the liquid crystal alignment solidification layer include liquid crystal polymers and liquid crystal monomers. Preferably, the liquid crystal compound is polymerizable (i.e., a liquid crystal monomer). If the liquid crystal compound is polymerizable, the orientation state of the liquid crystal compound can be fixed by polymerizing it after orientation. Here, the polymer formed by polymerization is non-liquid crystallized. Therefore, the formed liquid crystal alignment solidification layer does not undergo transitions to liquid crystal phase, glass phase, or crystalline phase due to temperature changes, which is characteristic of liquid crystal compounds. As a result, the liquid crystal alignment solidification layer becomes an extremely stable phase difference film that is unaffected by temperature changes.

[0029] In one embodiment, the liquid crystal alignment solidification layer may be formed using a composition containing a polymerizable liquid crystal compound (a polymerizable liquid crystal compound, i.e., a liquid crystal monomer). In this specification, a polymerizable liquid crystal compound included in the composition means a compound that has a polymerizable group and is liquid crystal. A polymerizable group means a group that participates in the polymerization reaction, and is preferably a photopolymerizable group. Here, a photopolymerizable group means a group that can participate in the polymerization reaction by active radicals or acids generated from a photopolymerization initiator. Examples of polymerizable mesogenic compounds can be used as liquid crystal monomers, such as those described in Japanese Patent Publication No. 2002-533742 (WO00 / 37585), EP358208 (US5211877), EP66137 (US4388453), WO93 / 22397, EP0261712, DE19504224, DE4408171, and GB2280445. Specific examples of such polymerizable mesogenic compounds include, for example, BASF's trade name LC242, Merck's trade name E7, and Wacker-Chem's trade name LC-Silicon-CC3767.

[0030] The mechanism by which the liquid crystalline properties of a liquid crystal compound are exhibited may be thermotropic or lyotropic. Furthermore, the liquid crystal phase may be composed of either a nematic or smectic liquid crystal. From the viewpoint of ease of manufacture, a thermotropic nematic liquid crystal is preferred.

[0031] The temperature range in which liquid crystal monomers exhibit liquid crystalline properties varies depending on the type. Specifically, the temperature range is preferably 40°C to 120°C, more preferably 50°C to 100°C, and most preferably 60°C to 90°C.

[0032] The liquid crystal alignment solidification layer may exhibit inverse dispersion wavelength characteristics in which the phase difference value increases with the wavelength of the measurement light, or it may exhibit positive wavelength dispersion characteristics in which the phase difference value decreases with the wavelength of the measurement light, or it may exhibit flat wavelength dispersion characteristics in which the phase difference value hardly changes with the wavelength of the measurement light.

[0033] A liquid crystal alignment solidification layer can be formed by applying an alignment treatment to the surface of a predetermined substrate (typically a support layer, which will be described in detail later), applying a coating liquid containing a liquid crystal compound to the surface to orient the liquid crystal compound in the direction corresponding to the alignment treatment, and fixing the alignment state.

[0034] Any suitable orientation treatment can be used as described above. Specifically, these include mechanical orientation treatment, physical orientation treatment, and chemical orientation treatment. Specific examples of mechanical orientation treatment include rubbing and stretching. Specific examples of physical orientation treatment include magnetic field orientation treatment and electric field orientation treatment. Specific examples of chemical orientation treatment include oblique deposition and photo-oriented orientation treatment. The processing conditions for each orientation treatment can be any suitable conditions depending on the purpose.

[0035] The orientation of liquid crystal compounds is achieved by treating them at a temperature that exhibits the liquid crystal phase, depending on the type of liquid crystal compound. This temperature treatment causes the liquid crystal compound to enter a liquid crystal state, and it then orients according to the orientation treatment direction of the support layer surface.

[0036] In one embodiment, the orientation state is fixed by cooling the liquid crystal compound oriented as described above. This is done by rejection. For the orientation to be fixed, the liquid crystal compound oriented as described above is subjected to polymerization or crosslinking treatment. It is done by applying [a specific method / technique].

[0037] For specific examples of liquid crystal compounds and details of the method for forming the oriented solidified layer, please refer to Japanese Patent Application Publication No. 2006-16334. It is described in Publication No. 3. The description in said publication is incorporated herein by reference.

[0038] The thickness of the liquid crystal alignment solidification layer can be adjusted to obtain the desired in-plane phase difference described above. The thickness of the liquid crystal alignment solidification layer may be, for example, 0.5 μm to 3.0 μm.

[0039] In one embodiment, the phase difference film 120a includes a first liquid crystal alignment solidification layer 121. Including the first liquid crystal alignment solidification layer in the phase difference film makes it possible to make the manufactured optical laminate thinner. In the illustrated example, the phase difference film 120a includes a first support layer 141 in addition to the first liquid crystal alignment solidification layer 121.

[0040] <Support layer> The support layer may be a layer that supports the liquid crystal alignment solidification layer. Specifically, the support layer is a component used, for example, to orient liquid crystal compounds. Any suitable resin film can be used as the support layer. Examples of resin films that can be used as the support layer include cycloolefin (COP) resins, polyester resins, cellulose resins, polycarbonate (PC) resins, and (meth)acrylic resins.

[0041] The support layer may be, for example, a member used to support the liquid crystal alignment solidification layer via an adhesive layer, or a member used to coat and form a liquid crystal compound, or a member used to transfer a liquid crystal alignment solidification layer formed on another member. In this case, an adhesive layer may or may not be provided between the support layer and the liquid crystal alignment solidification layer. In one embodiment, the liquid crystal alignment solidification layer (first liquid crystal alignment solidification layer 121) is supported by a support layer (first support layer 141) via a first adhesive layer 131.

[0042] <Adhesive layer> As described above, the adhesive layer is, for example, a layer for bonding the liquid crystal alignment solidification layer and the support layer. Any suitable adhesive or tack can be used as the adhesive layer. The adhesive may typically be an ultraviolet-curing adhesive. Examples of tacks include acrylic tacks.

[0043] As shown in Figure 1E or Figure 1F, in another embodiment, the first optical film 10 includes a polarizing plate 111.

[0044] B-1-2. Polarizing plate A polarizing plate 111 typically includes a polarizer 112. In the illustrated example, the polarizing plate 111 includes a polarizer 112 and protective layers (inner protective layer 113 and outer protective layer 114) arranged on the main surface of the polarizer 112 (on both sides of the main surface in the illustrated example). Depending on the purpose, the inner protective layer 113 and / or the outer protective layer 114 may be omitted from the polarizing plate 111. Therefore, the polarizing plate may be a so-called double-protected polarizing plate, a so-called single-protected polarizing plate, or composed of a polarizer alone. In this specification, a protective layer arranged on the outside (typically the viewing side) in an optical laminate may be referred to as an outer protective layer, and a protective layer arranged on the inside (typically the side opposite to the viewing side) may be referred to as an inner protective layer.

[0045] <Polarizer> The polarizer 112 is typically composed of a polyvinyl alcohol (PVA) resin film containing a dichroic substance (e.g., iodine). Examples of PVA resins include polyvinyl alcohol, partially formalized polyvinyl alcohol, ethylene-vinyl alcohol copolymer, and partially saponified ethylene-vinyl acetate copolymer.

[0046] The PVA resin preferably includes an acetoacetyl-modified PVA resin. With such a configuration, a polarizer with the desired mechanical strength can be obtained. The amount of acetoacetyl-modified PVA resin is preferably 5% to 20% by weight, more preferably 8% to 12% by weight, when the total PVA resin is considered to be 100% by weight. A polarizer with superior mechanical strength can be obtained when the amount is within this range.

[0047] The polarizer preferably contains iodide or sodium chloride (sometimes collectively referred to as halide). Examples of iodide include potassium iodide, sodium iodide, and lithium iodide. The halide content in the polarizer is preferably 5 to 20 parts by weight, more preferably 10 to 15 parts by weight, per 100 parts by weight of PVA resin. In the manufacturing method described later, the halide can be incorporated into the coating solution that forms the PVA resin layer, which is a precursor of the polarizer, and finally introduced into the polarizer. By introducing a halide into the polarizer, the orientation of PVA molecules in the polarizer can be increased, making it possible to realize a polarizer with excellent optical properties (typically, a combination of high polarization degree and high single-element transmittance).

[0048] The polarizer preferably exhibits absorption dichroism at a wavelength of 380 nm to 780 nm. The transmittance of the polarizer is preferably 41.0% to 46.0%, more preferably 42.0% to 45.0%. The degree of polarization of the polarizer is preferably 97.0% or higher, more preferably 99.0% or higher, and even more preferably 99.9% or higher. According to embodiments of the present invention, even if the transmittance of the polarizer is within the above range, the degree of polarization can be maintained within this range.

[0049] The thickness of the polarizer is, for example, 12 μm or less, preferably 10 μm or less, more preferably 1 μm to 8 μm, and even more preferably 3 μm to 7 μm. By combining such a thin polarizer with a liquid crystal alignment solidification layer, it is possible to significantly reduce the thickness of the optical laminate. Furthermore, if the thickness of the polarizer is within the above range, curling during heating can be well suppressed, and good appearance durability during heating can be obtained.

[0050] Polarizers can be manufactured by any suitable method. For example, the resin film forming the polarizer may be a single-layer resin film or may be obtained using a laminate of two or more layers.

[0051] Specific examples of polarizers composed of a single layer of resin film include hydrophilic polymer films such as PVA-based films, partially formalized PVA-based films, and partially saponified ethylene-vinyl acetate copolymer films that have been dyed with dichroic substances such as iodine or dichroic dyes and stretched, as well as polyene-based oriented films such as dehydrated PVA or dehydrochlorinated polyvinyl chloride. Preferably, polarizers obtained by dyeing a PVA-based film with iodine and uniaxially stretching it are used because they have excellent optical properties.

[0052] The above-mentioned iodine dyeing is carried out, for example, by immersing the PVA film in an iodine aqueous solution. The stretching ratio for the above-mentioned uniaxial stretching is preferably 3 to 7 times. Stretching may be performed after the dyeing treatment, or during the dyeing process. Alternatively, dyeing may be performed after stretching. If necessary, the PVA film may be subjected to swelling, crosslinking, washing, drying, etc. For example, immersing the PVA film in water and washing it before dyeing can not only clean dirt and anti-blocking agents from the surface of the PVA film, but also swell the PVA film to prevent uneven dyeing.

[0053] Specific examples of polarizers obtained using a laminate include a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer coated on the resin substrate. A polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer coated on the resin substrate can be produced, for example, by applying a PVA-based resin solution to a resin substrate, drying it to form a PVA-based resin layer on the resin substrate, and obtaining a laminate of the resin substrate and the PVA-based resin layer; or by stretching and dyeing the laminate to make the PVA-based resin layer a polarizer. In this embodiment, preferably, a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin is formed on one side of the resin substrate. Stretching typically includes immersing the laminate in an aqueous boric acid solution and stretching it. Furthermore, stretching may, if necessary, further include air-stretching the laminate at a high temperature (e.g., 95°C or higher) before stretching in the aqueous boric acid solution. In addition, in this embodiment, the laminate is preferably subjected to a drying shrinkage treatment in which it shrinks by 2% or more in the width direction by heating while being transported in the longitudinal direction. Typically, the polarizer manufacturing method of this embodiment includes applying an air-assisted stretching treatment, a dyeing treatment, a water-based stretching treatment, and a drying shrinkage treatment to the laminate in this order. By introducing auxiliary stretching, it is possible to increase the crystallinity of PVA even when PVA is coated on a thermoplastic resin, making it possible to achieve high optical properties. At the same time, by increasing the orientation of PVA in advance, it is possible to prevent problems such as a decrease in the orientation of PVA and dissolution when immersed in water in the subsequent dyeing and stretching processes, and to achieve high optical properties. Furthermore, when the PVA-based resin layer is immersed in a liquid, the disorder of the orientation of polyvinyl alcohol molecules and the decrease in orientation can be suppressed compared to when the PVA-based resin layer does not contain halides. As a result, the optical properties of the polarizer obtained through processing steps in which the laminate is immersed in a liquid, such as dyeing and water-based stretching, can be improved. Furthermore, by shrinking the laminate in the width direction through a drying shrinkage treatment, the optical properties can be improved. The resulting resin substrate / polarizer laminate may be used as is (i.e., the resin substrate may be used as a protective layer for the polarizer), or an appropriate protective layer may be laminated on the peeled surface obtained by removing the resin substrate from the resin substrate / polarizer laminate, or on the surface opposite to the peeled surface, depending on the purpose. Details of such polarizer manufacturing methods are described, for example, in Japanese Patent Application Publication No. 2012-73580 and Japanese Patent No. 6470455. The entire contents of these publications may be incorporated herein by reference.

[0054] <Protective layer> The protective layers 113 and 114 may be composed of any suitable resin film. Typical materials for the resin film include cellulosic resins such as triacetylcellulose (TAC), cycloolefin (COP) resins such as polynorbornene, (meth)acrylic resins, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyolefin resins such as polyethylene, and polycarbonate resins. Typical examples of (meth)acrylic resins include (meth)acrylic resins having a lactone ring structure. (Meth)acrylic resins having a lactone ring structure are described, for example, in Japanese Patent Publication No. 2000-230016, Japanese Patent Publication No. 2001-151814, Japanese Patent Publication No. 2002-120326, Japanese Patent Publication No. 2002-254544, and Japanese Patent Publication No. 2005-146084. These publications may be incorporated herein by reference. The materials constituting the resin film may preferably be cellulose resins (more preferably TAC resins), cycloolefin resins, and (meth)acrylic resins.

[0055] In one embodiment, the protective layer (inner protective layer) is preferably optically isotropic. In this specification, "optically isotropic" means that the in-plane phase difference Re(550) is 0 nm to 10 nm and the phase difference Rth(550) in the thickness direction is -10 nm to +10 nm.

[0056] For example, when an optical laminate is applied to an image display device, the optical laminate is typically positioned on the viewing side of the image display device, and therefore the outer protective layer is typically positioned on that viewing side. Accordingly, the outer protective layer may be surface-treated as needed. Examples of surface treatments include hard coating, anti-reflective coating, anti-sticking coating, and anti-glare coating. Furthermore / or, the outer protective layer may be treated as needed to improve visibility when viewed through polarized sunglasses (typically by providing (elliptic) polarization functionality or providing ultra-high phase difference). By applying such treatment, excellent visibility can be achieved even when viewing the display screen through polarized lenses such as polarized sunglasses. Accordingly, optical laminates can be suitably applied to image display devices that may be used outdoors.

[0057] The thicknesses of the protective layers 113 and 114 are preferably 10 μm to 80 μm, more preferably 12 μm to 40 μm, and even more preferably 15 μm to 35 μm, respectively. If the protective layer 114 is surface-treated, the thickness of the protective layer 114 includes the thickness of the surface treatment layer.

[0058] As shown in Figure 1F, in yet another embodiment, the first optical film 10 comprises a polarizing plate 111 and a phase difference film 120a. In the illustrated example, the polarizing plate 111 includes an (inner) protective layer 113, a polarizer 112, and an (outer) protective layer 114. The phase difference film 120a includes a first liquid crystal alignment solidification layer 121. In the first optical film 10, the polarizing plate 111 and the phase difference film 120a are bonded together via a first adhesive layer 131.

[0059] B-2. Details of the long film configuration Next, we will explain the details of the long film's construction. As described above, the long film includes a first optical film. The first optical film may be in the form of a long film or in the form of a single sheet. As shown in Figures 1A to 1F, in one embodiment, the long film 100 includes a long first optical film 10.

[0060] As shown in Figures 2A to 2B, the long film 100 may comprise a plurality of first optical films 10 having a single-sheet shape, and a base film 101 that supports the plurality of first optical films.

[0061] B-2-1. Base film The base film may function as a transport film for transporting the first optical film in a long film. The base film is typically in a long form.

[0062] As the base film, a resin film that can be used for any suitable conveying method may be used. The base film may be a resin film such as polyethylene terephthalate (PET) film, polyethylene (PE) film, or polypropylene (PP) film.

[0063] As shown in Figure 2B, the multiple first optical films 10, each having a single-sheet shape, are preferably positioned on the base film 101 with spacing between them in the longitudinal direction of the base film 101. With this configuration, even when the first optical films are in a single-sheet shape, the first optical films and the second optical films can be bonded together while transporting the long film. However, adjacent single-sheet first optical films are not connected by tape or the like, and are clearly separated from each other.

[0064] In one embodiment, a first optical film having a single sheet is attached to a long base film via an arbitrary suitable adhesive layer. Specifically, as shown in Figure 2B, the long film 100 is manufactured by attaching the first optical film 10 to a base film 101 via an adhesive layer 12 composed of an arbitrary suitable adhesive. The adhesive layer 12 is an element that can constitute the long film 100. Examples of adhesives used in the adhesive layer 12 include (meth)acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, epoxy adhesives, and polyether adhesives. By adjusting the type, number, combination and blending ratio of monomers forming the base resin of the adhesive, as well as the amount of crosslinking agent, reaction temperature, reaction time, etc., an adhesive with desired properties according to the purpose can be prepared. The base resin of the adhesive may be used alone or in combination of two or more types. As shown in the illustrated example, the long substrate film 101 and the first optical film 10 having a sheet-like structure may be bonded together via the adhesive layer 12, or the first optical film 10 having a sheet-like structure may be directly placed at any appropriate position on the long substrate film 101 without the adhesive layer. In other words, the adhesive layer is optional. The base film is typically peelable from the first optical film. The base film is ultimately peeled from the optical laminate, for example, which may be obtained according to embodiments of the present invention.

[0065] The above describes how to construct a long film using a long base film when the first optical film is in sheet form. However, as long as it does not hinder the effects of the present invention, a long base film may also be used when the first optical film is long. For example, a long film may be constructed by attaching a long first optical film to a long base film via an appropriate adhesive layer.

[0066] C. Second optical film The second optical film typically has a single-sheet structure as described above. The second optical film can be any suitable optical film having appropriate optical and / or mechanical properties, depending on the optical properties, material type, thickness, etc., of the optical film used as the first optical film, in order to obtain an optical laminate having the desired function when manufacturing an optical laminate according to an embodiment of the present invention. As the second optical film, any suitable optical film can be adopted depending on the desired properties of the optical laminate. Typical optical films used may be those similar to the optical films described above for the first optical film (such as polarizing plates and phase difference films). Therefore, the explanation in Section B-1 above may be applied to the second optical film. For the second optical film, for example, the same type of material (including laminates) as the first optical film may be used, or a different type of material (including laminates) may be used.

[0067] As shown in Figures 1D to 1F, in each embodiment, the second optical film 20 includes a phase difference film 120b. The phase difference film 120b of the second optical film 20 will be described in the same way as the phase difference film 120a of the first optical film 10. Therefore, a detailed description of the phase difference film 120b will be omitted as appropriate. In one embodiment, the phase difference film of the second optical film functions as a λ / 4 plate. When the phase difference film functions as a λ / 4 plate, the in-plane phase difference Re(550) of the phase difference film is preferably 100 nm to 190 nm, more preferably 110 nm to 170 nm, and even more preferably 130 nm to 160 nm.

[0068] In this specification, optical films used in the manufacture of optical laminates are designated as "first" if they can constitute the first optical film (e.g., first liquid crystal alignment solidification layer, first support layer, first adhesive layer) and as "second" if they can constitute the second optical film (e.g., second liquid crystal alignment solidification layer, second support layer, second adhesive layer). However, these are merely expressions used for convenience to distinguish them. Therefore, the optical films that can be used for the first optical film and the second optical film can be appropriately selected according to the purpose of the optical laminate. Accordingly, as long as the purpose of the present invention is not hindered, the optical film used for the first optical film and the optical film used for the second optical film may be interchanged when manufacturing an optical laminate according to an embodiment of the present invention.

[0069] In one embodiment, the phase difference film 120b has a second liquid crystal alignment solidification layer 122. In the illustrated example, the phase difference film 120b includes a second support layer 142 in addition to the second liquid crystal alignment solidification layer 122. In one embodiment, the second liquid crystal alignment solidification layer 122 is supported by the second support layer 142 via a second adhesive layer 132. The second liquid crystal alignment solidification layer 122 preferably functions as a λ / 4 plate. With this configuration, good anti-reflective properties can be imparted to the optical laminate.

[0070] The widthwise dimension of the second optical film can be set to an appropriate dimension depending on the dimensions, shape, etc., of the first optical film, as long as it does not hinder the objective of the present invention. Preferably, the widthwise dimension of the second optical film may be the same as the widthwise dimension of the long film, or slightly shorter than the widthwise dimension of the long film. In a second optical film having multiple sheets, the widthwise dimensions of each second optical film do not necessarily have to be the same.

[0071] D. Details of the manufacturing method for optical laminates Next, the details of the method for manufacturing an optical laminate according to an embodiment of the present invention will be described with reference to the drawings. As shown in Figure 1A, a method for manufacturing an optical laminate according to an embodiment of the present invention may include a step of preparing materials that can constitute an optical laminate (preparation step), a step of transporting a long film 100 including a first optical film 10 (transportation step), and a step of attaching a sheet-like second optical film 10 to the first optical film via an adhesive constituting an adhesive layer (30) (attachment step).

[0072] D-1. First Embodiment Figure 1A shows a part of the process for manufacturing an optical laminate according to the first embodiment of the present invention. The first embodiment will be described in detail below. D-1-1. Preparation process In the first embodiment, the preparation step involves preparing a long film 100 containing the first optical film 10 described above, and a second optical film 20 having a sheet-like shape as described above. In this embodiment, the long first optical film 10 is the long film 100. The details of the long film and the second optical film are as described in sections B and C above, respectively.

[0073] The widthwise dimension of the sheet-like second optical film is typically the same as the widthwise dimension of the long film, or slightly shorter than the widthwise dimension of the long film. The longitudinal dimension of the sheet-like second optical film may be the same as the widthwise dimension of the second optical film, or it may be slightly longer or shorter than the widthwise dimension of the second optical film. The ratio of the widthwise dimension to the longitudinal dimension of the sheet-like second optical film is preferably 1:0.5 to 1:2.0, and more preferably 1:0.8 to 1:1.5. Within this range, the difference in the change in the dimensional ratio between the longitudinal and widthwise directions can be suppressed particularly well without impairing the manufacturing efficiency of the optical laminate.

[0074] D-1-2.Transportation process In the first embodiment, the transport process transports a long film 100 containing the first optical film 10 as described above. In this embodiment, the first optical film 10 is long in length. With this configuration, when manufacturing an optical laminate, it is possible to feed a single long object (typically the first optical film) from a roll, transport it, feed it to the next process, and recover the manufactured product (including intermediate products), thereby improving manufacturing efficiency. Specifically, in the transport process, as shown in Figure 1A, the long film 100 containing the first optical film 10 is fed from the feed roll and the long film 100 is transported.

[0075] D-1-3. Pasting Process In the first embodiment, during the bonding process, a sheet-like second optical film 20 is bonded to the first optical film 10 via a curable adhesive. Specifically, as shown in Figure 1A, the curable adhesive is supplied to desired positions on the first optical film 10 while the long film 100 (substantially the first optical film 10) is conveyed in the longitudinal direction.

[0076] Preferably, active energy ray curing adhesives and thermosetting adhesives can be used as curing adhesives. Examples of active energy ray curing adhesives include ultraviolet curing adhesives and electron beam curing adhesives. When the curing adhesive is composed of an active energy ray curing adhesive, it can be cured by irradiation with active energy rays (e.g., ultraviolet rays, electron beams). From the perspective of curing mechanism, active energy ray curing adhesives include, for example, radical curing type, cationic curing type, anionic curing type, and hybrids of radical curing type and cationic curing type. Typically, radical curing type UV curing adhesives can be used because they offer excellent versatility and their properties (composition) can be easily adjusted.

[0077] Curing adhesives typically contain a curing component and a photopolymerization initiator. Typical curing components include monomers and / or oligomers having functional groups such as (meth)acrylate groups and (meth)acrylamide groups. Specific examples of curing components include tripropylene glycol diacrylate, 1,9-nonanediol diacrylate, tricyclodecanedimethanol diacrylate, phenoxydiethylene glycol acrylate, cyclic trimethylolpropane formal acrylate, dioxane glycol diacrylate, EO-modified diglycerin tetraacrylate, γ-butyrolactone acrylate, acryloylmorpholine, unsaturated fatty acid hydroxyalkyl ester-modified ε-caprolactone, N-methylpyrrolidone, hydroxyethylacrylamide, N-methylolacrylamide, N-methoxymethylacrylamide, and N-ethoxymethylacrylamide. These curing components may be used alone or in combination of two or more.

[0078] Since the photopolymerization initiator can be a well-known one in the industry and used in a well-known proportion, a detailed explanation will be omitted.

[0079] The curing adhesive may be in liquid form, or it may be in a semi-cured form.

[0080] Details of the curing adhesive are described, for example, in Japanese Patent Publication No. 2018-017996. The description in said publication is incorporated herein by reference.

[0081] Next, a second optical film 20 having a sheet-like structure is attached to the first optical film 10 via a curing adhesive on the first optical film 10. In this embodiment, during the attachment process, multiple second optical films 20 are attached to the first optical film 10 so that they are spaced apart from each other in the longitudinal direction of the long film 100 (see Figures 1A and 1B). The shorter the spacing between the multiple second optical films, the better. Specifically, the spacing should be such that the multiple sheet-like second optical films are not connected to each other by tape or the like in the longitudinal direction, but are arranged intermittently in the longitudinal direction. The spacing between the second optical films is preferably 30 mm or less, more preferably 10 mm or less. The upper limit of the spacing may be 100 mm. In this way, the waste of the long film can be reduced.

[0082] Next, the curable adhesive is cured. The curing method can be an appropriate method depending on the composition and type of the curable adhesive. For example, in the bonding process, after the second optical film is bonded to the long film via the curable adhesive, the curable adhesive is irradiated with active energy rays while being transported. This cures the curable adhesive and can form an adhesive layer 30 interposed between the long film 100 and the second optical film 20.

[0083] <Adhesive layer> As described above, the adhesive layer is interposed between the first optical film and the second optical film in the optical laminate. The adhesive layer according to the embodiment of the present invention can be made from any suitable curable adhesive. Typically, the adhesive layer is composed of a cured product of a curable adhesive.

[0084] The thickness of the adhesive layer (after curing of the curable adhesive) is, for example, 0.1 μm to 3.0 μm. Preferably, the thickness of the adhesive layer is 2 μm or less, more preferably 1.5 μm or less, and even more preferably 1.0 μm or less. Within this range, it can further contribute to the thinning of the optical laminate. As described later, the adhesive layer and its thickness can contribute to the exhibiting of even better effects in relation to the first surface film and the second surface film that are in contact with the adhesive layer.

[0085] The thickness variation in the adhesive layer is, for example, 0.15 μm or less, preferably 0.05 μm or less, and more preferably 0.01 μm or less. The lower limit of the thickness variation in the adhesive layer is typically 0.0001 μm (0.1 nm). When the thickness variation in the adhesive layer is within this range, excellent optical properties can be stably imparted to the optical laminate, and interference unevenness in the optical laminate can be sufficiently suppressed. In this specification, the thickness variation in the adhesive layer includes waviness formed by curing shrinkage. That is, the thickness variation in the adhesive layer is the variation in optical path length. The thickness variation in the adhesive layer is measured, for example, by an interference film thickness gauge, SEM, or TEM.

[0086] <First surface film and second surface film> The first optical film may have a first surface film, which is a layer in the first optical film that comes into contact with the adhesive layer. The second optical film may have a second surface film, which is a layer in the second optical film that comes into contact with the adhesive layer. Specifically, in the bonding process, the first optical film comprises a first surface film that comes into contact with the adhesive layer formed by the curing of the curing adhesive; and the second optical film comprises a second surface film that comes into contact with the adhesive layer formed by the curing of the curing adhesive. The thickness of at least one of the first surface film and the second surface film is preferably 5 μm or less, more preferably 4 μm or less, even more preferably 3 μm or less, and particularly preferably 2 μm or less. The lower limit of the thickness of at least one of the first surface film and the second surface film may be, for example, 0.5 μm. Within this range, it can significantly contribute to making the resulting optical laminate thinner. In particular, when the thickness of the adhesive layer 30 is 2 μm or less, if the thicknesses of the first surface film and the second surface film are within the above-mentioned range, it can significantly contribute to the thinning of the optical laminate.

[0087] As shown in Figures 1D to 1F, in one embodiment, the layer in contact with the adhesive layer 30 in the first optical film 10 is the first surface film 11; and the layer in contact with the adhesive layer 30 in the second optical film 20 is the second surface film 21. The first surface film 11 is preferably a polarizer 112 or a first liquid crystal alignment solidification layer 121. The second surface film 21 is preferably a second liquid crystal alignment solidification layer 122.

[0088] The first surface film 11 is preferably a first liquid crystal alignment solidification layer 121 and functions as a λ / 2 plate. In this case, more preferably the second surface film 21 is a second liquid crystal alignment solidification layer 122 and functions as a λ / 4 plate. With this configuration, the phase difference layer (phase difference film) as a whole can function as λ / 4, and as a result, a good anti-reflective function can be imparted to the optical laminate.

[0089] In one embodiment, with the first optical film and the second optical film laminated together, the angle between the slow axis of the first liquid crystal alignment solidification layer and the absorption axis of the polarizer is preferably 10° to 20°, more preferably 12° to 18°, and even more preferably about 15°; the angle between the slow axis of the second liquid crystal alignment solidification layer 122 and the absorption axis of the polarizer 10 is preferably 70° to 80°, more preferably 72° to 78°, and even more preferably about 75°. With such a configuration, it is possible to obtain characteristics close to ideal inverse wavelength dispersion characteristics, and as a result, an optical laminate with very excellent anti-reflective properties can be realized.

[0090] D-1-4. Other processes The method for manufacturing an optical laminate according to the first embodiment may further include steps other than those described above. For example, a peeling step may be included. Specifically, layers that are unnecessary when the optical laminate is used for a desired application may be peeled off. For example, when the optical laminate is used in an image display device, a second support layer (the outermost layer of the optical laminate) that can be attached to the display panel of the image display device may be peeled off. Note that the peeling off of the unnecessary layers from the optical laminate may be performed at any appropriate time after the optical laminate has been obtained and is being used for a desired application, rather than during the manufacturing process of this embodiment.

[0091] Furthermore, the process may also include a cutting step. Specifically, a single-sheet optical laminate may be produced by cutting a long optical laminate to a desired size. The cutting of the long optical laminate may be performed, for example, while it is being transported.

[0092] In this way, an optical laminate 1 can be manufactured having a long film 100 including the first optical film 10, an adhesive layer 30, and a second optical film 20 in this order (see Figure 1C).

[0093] D-1-5. Specific Examples of Optical Laminates As described above, by appropriately selecting the type of long film (essentially the first optical film) and the second optical film according to the purpose and going through the process described above, a desired optical laminate can be obtained. According to the manufacturing method of the optical laminate according to the first embodiment, for example, the optical laminates shown in Figures 1D to 1F can be manufactured.

[0094] As shown in Figure 1D, for example, in the bonding process, a long film 100 is used, which includes a long first optical film 10 (phase difference film 120a) having a first support layer 141, a first adhesive layer 131, and a first liquid crystal alignment solidification layer 121 in that order; and a second optical film 20 (phase difference film 120b) having multiple sheets having a second liquid crystal alignment solidification layer 122, a second adhesive layer 132, and a second support layer 142 in that order. In this case, the optical laminate 1 shown in Figure 1D can be obtained by bonding the first liquid crystal alignment solidification layer 121 and the second liquid crystal alignment solidification layer 122 via an adhesive layer 30 composed of a curable adhesive. In the optical laminate 1, the first surface film 11 may be the first liquid crystal alignment solidification layer 121, and the second surface film 21 may be the second liquid crystal alignment solidification layer 122. The optical laminate 1 can function, for example, as a multilayer phase difference layer (phase difference film).

[0095] For example, as shown in Figure 1E, a long film 100 is used which includes a long first optical film 10 (polarizing plate 111) having a protective layer 114 and a polarizer 112; and a second optical film 20 (phase difference film 120b) having multiple sheets in which a second liquid crystal alignment solidification layer 122, a second adhesive layer 132, and a second support layer 142 are present in that order. In this case, the optical laminate 1 shown in Figure 1E can be obtained by bonding the polarizer 112 and the second liquid crystal alignment solidification layer 122 via an adhesive layer 30 composed of a curing adhesive. In the optical laminate 1, the first surface film 11 may be a polarizer 112, and the second surface film 21 may be a second liquid crystal alignment solidification layer 122. The optical laminate 1 can function as, for example, a polarizing film or a circularly polarizing film.

[0096] For example, as shown in Figure 1F, a long film 100 is used which includes a polarizing plate 111, a first adhesive layer 131, and a first liquid crystal alignment solidification layer 121 in that order; and a second optical film 20 (phase difference film 120b) having multiple sheets, which includes a second liquid crystal alignment solidification layer 122, a second adhesive layer 132, and a second support layer 142 in that order. In this case, the optical laminate 1 shown in Figure 1F can be obtained by bonding the first liquid crystal alignment solidification layer 121 and the second liquid crystal alignment solidification layer 122 via an adhesive layer 30 made of a curable adhesive. In this embodiment, the inner protective layer 113 of the polarizing plate 111 can also function as a support layer for the first liquid crystal alignment solidification layer 121. The optical laminate 1 can function as, for example, a polarizing film or a circularly polarizing film.

[0097] However, as stated above, the specific configurations of the optical laminates described above are examples, and the optical laminates that can be obtained by the manufacturing method according to the above embodiments of the present invention are not limited to these. The same applies to the embodiments described later. The present invention further includes the following specific embodiments (the second to fourth embodiments). In the following descriptions of the second to fourth embodiments, descriptions that overlap with the configuration described in the first embodiment will be omitted as appropriate.

[0098] D-2. Second Embodiment Figure 2A shows a part of the process for manufacturing an optical laminate according to the second embodiment of the present invention. As shown in Figure 2B, in the second embodiment, a long film 100 is used as the long film, comprising a long base film 101 and a plurality of first optical films 10 having a sheet-like shape. This embodiment may be substantially an embodiment in which the long film prepared in the preparation step of the first embodiment is changed to a long film composed of a long base film having a sheet-like shape and a plurality of first optical films having a sheet-like shape as described above. The long film comprising a long base film having a sheet-like shape and first optical films having a sheet-like shape is as described in Section B-2.

[0099] A long film may be manufactured by sequentially attaching multiple single-sheet first optical films to a base film via an appropriate adhesive layer while the base film is being transported. For example, to prepare the long film used in this embodiment, a long base film wound in a roll may be unwound, adhesive may be supplied to the base film at any appropriate position in the longitudinal direction, and then the single-sheet first optical films may be sequentially attached to the base film via the adhesive. Alternatively, to prepare the long film used in this embodiment, a long base film wound in a roll may be unwound, and the single-sheet first optical films, each with an adhesive layer pre-applied to it, may be sequentially attached to the base film via the adhesive layer. The long film thus manufactured may then be transported and subjected to a transport process and an attachment process.

[0100] The distance between adjacent first optical films located in the longitudinal direction of the base film can be any appropriate distance, as long as a second optical film is attached to it.

[0101] The transport of the long film (transportation process), the supply of the second optical film, and the attachment of the long film (first optical film) and the second optical film (attachment process) are described in the same manner as in the first embodiment. In this embodiment, in the attachment process, preferably, each of the multiple filaments of the second optical film may be attached so as to overlap each of the multiple filaments of the first optical film while the long film is being transported. Preferably, the first optical film and the second optical film to be attached are substantially the same in dimensions. Substantially the same does not mean strictly the same, but includes cases where there is a dimensional difference that is recognized as a dimensional error. The dimensional error may be within ±1.0 mm.

[0102] By following the process described above, an optical laminate 1 can be manufactured having, in this order, a long film 100 comprising a long base film 101 and a plurality of first optical films 10 having a sheet-like shape, an adhesive layer 30, and a second optical film 20 (see Figure 2B). In the manufacturing method of this embodiment, deviations from the desired dimensional ratio between the length direction and the width direction in the optical laminate can be suppressed. In particular, in this embodiment, since both the first optical film 10 and the second optical film 20 have a sheet-like shape, the effect of suppressing deviations between the dimensional ratio between the length direction and the width direction in the optical laminate can be further enhanced.

[0103] In this embodiment as well, similar to the first embodiment, a desired optical laminate can be obtained by appropriately selecting the types of the first optical film and the second optical film according to the purpose.

[0104] D-3. Third Embodiment Figure 3A shows a part of the process for manufacturing an optical laminate according to the third embodiment of the present invention. In the third embodiment, a plurality of second optical films 20 are transported by a carrier film 40 and supplied to the first optical film 10. Substantially, the transport of the long film 100 (first optical film 10) is the same as in the first embodiment, but it differs from the first embodiment in that a plurality of filamentous second optical films 20 are sequentially attached to the carrier film 40 via an adhesive layer 50 in the transport direction of the carrier film 40, and then the plurality of second optical films 20 are supplied to the long film 100 (first optical film 10).

[0105] The carrier film 40 can typically be a long film. Any suitable transportable resin film can be used as the carrier film. The resin film can be the same as the base film used in the long film described in Section B-2 above. The carrier film 40 and the second optical film 20 are bonded together, for example, via an adhesive layer 50. The structure of the adhesive layer 50 can be the same as that of the adhesive layer 12 used in the long film 100 (see Section B-2).

[0106] In the above, the adhesive layer 50 may be pre-placed on the surface of the carrier film 40. In this case, it is not necessary to supply multiple second optical films 20 and adhesive 50 to the carrier film 40 each time. Therefore, the first optical film 10 and the second optical film 20 can be bonded together via the adhesive layer 30 while transporting the long film 100 and the carrier film 40 (essentially a laminate having the second optical film 20, adhesive 50, and carrier film 40) together. As a result, the manufacturing efficiency of the optical laminate can be further improved. Even when manufactured in this way, since the second optical film is in sheet form, deviations in dimensional ratio due to transport tension can be suppressed, and an optical laminate with a stable and desired dimensional ratio can be obtained.

[0107] The transport of the multiple filamentous second optical film 20 by the carrier film 40 as described above is described in the same way as in the second embodiment, where the multiple filamentous first optical film is arranged on a long base film so as to be spaced apart from each other in the longitudinal direction of the base film. Specifically, by sequentially attaching the multiple filamentous second optical film 20 to the carrier film 40 via an arbitrary appropriate adhesive layer 50 while transporting the carrier film 40, a laminate can be obtained in which the multiple filamentous optical film 20 is attached to the carrier film 40. In the laminate, preferably the multiple filamentous second optical film 20 is spaced apart from each other in the longitudinal direction of the carrier film 40.

[0108] Multiple second optical films 20 are positioned (adjacent) in the longitudinal direction of the carrier film 40. The spacing between the second optical films 20 can be set to an appropriate interval depending on the widthwise dimension and / or longitudinal dimension of the first optical film 10. The widthwise dimension of the second optical film is typically the same as the widthwise dimension of the longitudinal film, or slightly shorter than the widthwise dimension of the longitudinal film. For example, the longitudinal dimension of the second optical film may be the same as the widthwise dimension of the second optical film, slightly longer than the widthwise dimension of the second optical film, or slightly shorter. The ratio of the widthwise dimension to the longitudinal dimension of the sheet-like second optical film is preferably 1:0.5 to 1:2.0, and more preferably 1:0.8 to 1:1.5. Within this range, the difference in the change in the dimensional ratio between the longitudinal and widthwise directions can be suppressed particularly well without impairing the manufacturing efficiency of the optical laminate.

[0109] In the illustrated example (Figure 3A, etc.), the second optical film 20 is arranged on the carrier film 40 in a drop-off manner, where the second optical film 20 is supplied one by one from above the carrier film 40. However, any suitable method can be used for supplying the second optical film to the carrier film. For example, the second optical film may be arranged in a pickup manner, where it is supplied one by one from below the carrier film.

[0110] As described above, an optical laminate 1 can be manufactured having, in this order, a long film 100 including a first optical film 10, an adhesive layer 30, a second optical film 20 having multiple filaments, an adhesive layer 50, and a carrier film 40 (see Figure 3B). According to the manufacturing method of this embodiment, in addition to suppressing deviations in the dimensional ratio between the longitudinal direction and the width direction in the optical laminate, the optical laminate can be manufactured by substantially transporting not only the long film but also the second optical film having filaments. As a result, the yield can be improved compared to the first embodiment, and the production efficiency of the optical laminate can be improved.

[0111] In this embodiment as well, similar to the first and second embodiments, a desired optical laminate can be obtained by appropriately selecting the types of the first optical film and the second optical film according to the purpose.

[0112] D-4. Fourth Embodiment In the fourth embodiment, a second optical film 20 having multiple sheets is transported by a carrier film 40, and the second optical film 20 having multiple sheets is supplied to a first optical film 10 having multiple sheets located on a base film 101. Regarding the preparation steps in this embodiment, the preparation of the long film (including the first optical film, adhesive layer, and base film), the second optical film, carrier film, curable adhesive, etc. will be described in the same manner as in the first to third embodiments. Regarding the transport process in this embodiment, the transport of the long film 100 having the base film 101 and the first optical film 10 will be described in the same manner as in the second embodiment. Regarding the bonding process in this embodiment, the transport of the second optical film 20 by the carrier film 40, the supply of the second optical film 20 having multiple sheets to the first optical film 10 having a sheet, and the bonding of the second optical film 20 to the first optical film 10 via an adhesive layer 30 composed of a curing adhesive will be described in the same manner as in the third embodiment.

[0113] As described above, an optical laminate 1 can be manufactured having, in this order, a long film 100 comprising a long base film 101, an adhesive layer 12, and a first optical film 10 having multiple sheets, an adhesive layer 30, a second optical film 20, an adhesive layer 50, and a carrier film 40 (see Figure 4). In the manufacturing method of this embodiment, deviations in the dimensional ratio between the length direction and the width direction in the optical laminate can also be suppressed. In particular, in this embodiment, since both the first optical film 10 and the second optical film 20 have a sheet-like shape, the effect of suppressing deviations in the dimensional ratio between the length direction and the width direction in the optical laminate can be further enhanced. Furthermore, the optical laminate can be manufactured by substantially transporting the second optical film which has a sheet-like shape. As a result, compared to the first embodiment, the yield can be improved and the production efficiency of the optical laminate can be improved.

[0114] In this embodiment as well, similar to the first to third embodiments, a desired optical laminate can be obtained by appropriately selecting the types of the first optical film and the second optical film according to the purpose.

[0115] E. Applications of optical laminates The optical laminate obtained by the manufacturing method according to the above embodiment can be used for any suitable application, depending on the type and combination of optical films (first optical film and second optical film) used in the manufacturing process as described above.

[0116] Preferred applications for optical laminates include polarizers (polarizing films) containing polarizers, circular polarizers, phase difference layers (phase difference films), and phase difference films that can function as λ / 4 plates. Optical laminates can be used for anti-reflective applications or as polarizers for organic EL displays. Optical laminates can typically be applied to image display devices. Typical examples of image display devices include liquid crystal displays and organic EL displays. An image display device according to one embodiment of the present invention typically includes the optical laminate on its viewing side. For example, the optical laminate has an adhesive layer (not shown) on the outermost layer side (e.g., the second liquid crystal alignment solidification layer) of the image display device, on the image display panel side, and is attachable to the image display panel. In this case, it is preferable that a release liner is temporarily attached to the surface of the adhesive layer until the optical laminate is put into use. By temporarily attaching the release liner, the adhesive layer is protected and roll formation of the optical laminate is made possible. [Examples]

[0117] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The measurement and evaluation methods in the examples are as follows. Unless otherwise specified, "parts" and "%" in the examples are based on weight.

[0118] (1) Thickness The measurement was taken using an interferometric film thickness gauge (Otsuka Electronics Co., Ltd., "MCPD9800").

[0119] (2) Interference unevenness (linear unevenness) The samples obtained in the examples and comparative examples were observed visually from the λ / 4 plate side under a three-wavelength fluorescent lamp in a non-illuminated state and evaluated according to the following criteria. ○ (Excellent): No linear unevenness was observed even when a polarizing plate was attached to a three-wavelength fluorescent lamp. × (Unacceptable): Linear unevenness that is practically unacceptable was observed during normal observation using a three-wavelength fluorescent lamp. Specifically, "interference unevenness (linear unevenness)" refers to the phenomenon in which, under a three-wavelength light source, thin lines with a particularly prominent pink color are visible throughout the reflection, mainly in the direction of the polarizer's absorption axis. In the bonding process described later, if anisotropy occurs in the curing shrinkage of the curing adhesive, thickness unevenness occurs in the adhesive layer composed of the curing adhesive, and interference unevenness (linear unevenness) is observed.

[0120] [Manufacturing Example 1: Production of Long Film A1] A photopolymerizable liquid crystal compound exhibiting a nematic liquid crystal phase (BASF's "Paliocolor LC242," chemical formula below) was dissolved in cyclopentanone to prepare a solution with a solid content of 30% by weight. A surfactant (BYK-360, BYC-Chemie) and a photopolymerization initiator (Omnirad907, IGM Resins) were added to this solution to prepare a liquid crystal composition solution. The amounts of surfactant and polymerization initiator added were 0.01 parts by weight and 3 parts by weight, respectively, per 100 parts by weight of the photopolymerizable liquid crystal compound. A biaxially oriented norbornene resin (COP) film was prepared as a substrate. The above liquid crystal composition was coated onto this substrate using a bar coater so that Re(550) was 275 nm, and the film was heated at 100°C for 3 minutes to orient the liquid crystal. After cooling to room temperature, the film was exposed to a nitrogen atmosphere with an integrated light intensity of 400 mJ / cm². 2 Photocuring was performed by irradiating with ultraviolet light. Next, the cured liquid crystal layer (first liquid crystal alignment solidification layer) was transferred to another substrate (COP film: Re(550)≒0nm), and by peeling off the above substrate, a long film A1 having the configuration of first support layer (COP) / first liquid crystal alignment solidification layer was obtained. The first liquid crystal alignment solidification layer was homogeneously oriented, and its thickness was 2.0 μm. Hereafter, the length direction will be referred to as the "0° direction" and the width direction as the "90° direction". The slow phase axis direction of the first liquid crystal alignment solidification layer was 90° (relative to the length direction). The first liquid crystal alignment solidification layer functions as a λ / 2 plate. [ka]

[0121] [Manufacturing Example 2: Production of A2 long film] (Fabrication of polarizers) As a thermoplastic resin substrate, an amorphous isophthalic copolymer polyethylene terephthalate film (thickness: 100 μm) in a long length with a Tg of approximately 75°C was used, and one side of the resin substrate was subjected to corona treatment. A PVA aqueous solution (coating solution) was prepared by dissolving 100 parts by weight of a PVA-based resin, which was prepared by mixing polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gosephymer") in a 9:1 ratio, with 13 parts by weight of potassium iodide. A PVA aqueous solution was applied to the corona-treated surface of a resin substrate and dried at 60°C to form a 13 μm thick PVA-based resin layer, thereby creating a laminate. The resulting laminate was uniaxially stretched 2.4 times in the longitudinal direction (longitudinal direction) in an oven at 130°C (air-assisted stretching). Next, the laminate was immersed for 30 seconds in an insolubilization bath at a liquid temperature of 40°C (a boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) (insolubilization treatment). Next, the polarizers were immersed for 60 seconds in a staining bath at a liquid temperature of 30°C (an iodine aqueous solution obtained by mixing iodine and potassium iodide in a weight ratio of 1:7 with 100 parts by weight of water) while adjusting the concentration so that the final transmittance (Ts) of the polarizers obtained would be the desired value (staining treatment). Next, the laminate was immersed for 30 seconds in a crosslinking bath at a liquid temperature of 40°C (a boric acid aqueous solution obtained by mixing 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with 100 parts by weight of water) (crosslinking treatment). Subsequently, the laminate was immersed in a boric acid aqueous solution (boric acid concentration 4% by weight, potassium iodide concentration 5% by weight) at a liquid temperature of 70°C, and uniaxially stretched in the longitudinal direction (longitudinal direction) between rolls with different peripheral speeds to achieve a total stretch ratio of 5.5 times (underwater stretching treatment). Subsequently, the laminate was immersed in a washing bath at a liquid temperature of 20°C (an aqueous solution obtained by mixing 4 parts by weight of potassium iodide with 100 parts by weight of water) (washing treatment). Subsequently, the laminate was dried in an oven maintained at approximately 90°C while being brought into contact with a SUS (stainless steel) heated roll whose surface temperature was maintained at approximately 75°C (drying shrinkage treatment). In this manner, a polarizer with a thickness of 5 μm was formed on a resin substrate, and a long polarizing plate P1 having a resin substrate / polarizer configuration was obtained. The transmittance Ts of the polarizer alone was 43.3%. The polarizer had an absorption axis in the longitudinal direction. In this specification, the longitudinal direction is defined as the absorption axis direction, and the width direction is defined as the transmission axis direction.

[0122] (Fabrication of polarizing plates) An HC-COP film was bonded to the surface of the obtained polarizer (the side opposite to the resin substrate) via an ultraviolet-curing adhesive. The HC-COP film is a film in which an HC layer (4 μm thick) is formed on a cycloolefin resin (COP) film (25 μm thick), and it was bonded so that the COP film was on the polarizer side. Next, the resin substrate was peeled off, and a triacetylcellulose (TAC) film (25 μm thick) was bonded to the peeled surface via an ultraviolet-curing adhesive. In this way, a long polarizing plate P2 having the structure of outer protective layer (HC layer / COP) / polarizer / inner protective layer (TAC) was obtained.

[0123] (Fabrication of polarizing plates with phase difference layer) The first liquid crystal alignment solidification layer of a long film A1 having the configuration of a first support layer (COP) / first liquid crystal alignment solidification layer prepared in Manufacturing Example 1 was bonded to the inner protective layer (TAC) surface of the obtained long polarizing plate P2 using a UV-curable adhesive via a roll-to-roll method. Next, the UV-curable adhesive was cured. In this way, a long film A2 having the configuration of an outer protective layer (HC layer / COP) / polarizer / inner protective layer (TAC) / adhesive layer / first liquid crystal alignment solidification layer / first support layer (COP) was obtained.

[0124] [Manufacturing Example 3: Production of A3-size long film] (Fabrication of polarizing plates) The long polarizing plate (P1) having the resin substrate (protective layer: PET) / polarizer configuration of Manufacturing Example 2 was used as the long film A3.

[0125] [Manufacturing Example 4: Production of A4-sized long film] A long film A4 having a substrate (second support layer: COP) / second liquid crystal alignment solidification layer configuration was obtained in the same manner as the first liquid crystal alignment solidification layer in Manufacturing Example 1, except that the coating thickness was changed so that Re(550) was 175 nm. The slow phase axis direction of the second liquid crystal alignment solidification layer was 75°. The second liquid crystal alignment solidification layer functions as a λ / 4 plate. The thickness of the second liquid crystal alignment solidification layer was 1.0 μm.

[0126] [Manufacturing Example 5: Preparation of a single-sheet optical film B1] The long film A1 produced in Manufacturing Example 1 was cut to a width of 1290 mm and a length of 1500 mm. In this way, multiple sheets of single-wafer optical film B1 having the configuration of a first support layer (COP) / first liquid crystal alignment solidification layer were produced.

[0127] [Manufacturing Example 6: Preparation of a single-sheet optical film B2] A long film A2, having the configuration of an outer protective layer (HC layer / COP) / polarizer / inner protective layer (TAC) / adhesive layer / first liquid crystal alignment solidification layer / first support layer (COP) as prepared in Manufacturing Example 2, was cut to a width of 1290 mm and a length of 1500 mm. Next, the first support layer was peeled off from the cut film. In this way, multiple single-wafer optical films B2 having the configuration of a polarizer / protective layer (TAC) / adhesive layer / first liquid crystal alignment solidification layer were prepared.

[0128] [Manufacturing Example 7: Preparation of a single-sheet optical film B3] A long film A3 having the protective layer (PET) / polarizer configuration prepared in Manufacturing Example 3 was cut to a width of 1290 mm and a length of 1500 mm. Multiple sheets of single-wafer optical film B3 having the protective layer (PET) / polarizer configuration were prepared in this manner.

[0129] [Manufacturing Example 8: Preparation of a single-sheet optical film B4] A long film A4 having the second support layer (PET) / second liquid crystal alignment solidification layer configuration prepared in Manufacturing Example 4 was cut to a width of 1290 mm and a length of 1500 mm. In this way, multiple sheets of single-wafer optical film B4 having the second support layer (COP) / second liquid crystal alignment solidification layer configuration were prepared.

[0130] [Manufacturing Example 9: Preparation of a long film C1 having a base film] While conveying a long substrate film (PET film: manufactured by Toray Industries, Inc., product name "Lumirror", thickness 38 μm), multiple sheets (10 sheets) of the single-sheet optical film B1 prepared in Manufacturing Example 5 were arranged on the substrate film at intervals from each other in the longitudinal direction via an adhesive. The spacing between adjacent single-sheet optical films B1 on the substrate film was 3 mm. An acrylic adhesive was used as the adhesive. In this way, a long film C1 was obtained in which multiple laminates having the configuration of an adhesive layer / first support layer (COP) / first liquid crystal alignment solidification layer were arranged at intervals on the long substrate film.

[0131] [Manufacturing Example 10: Preparation of a long film C2 having a base film] A long film C2 having a base film was prepared in the same manner as in Manufacturing Example 9, except that a single-sheet optical film B2 from Manufacturing Example 6 was used. In this way, a long film C2 was obtained in which multiple laminates having the configuration of an adhesive layer / outer protective layer (HC layer / COP) / polarizer / inner protective layer (TAC) / adhesive layer / first liquid crystal alignment solidification layer / first support layer (COP) were arranged at intervals on the long base film.

[0132] [Manufacturing Example 11: Preparation of Long Film C3 Having a Base Film] A long film C3 having a base film was prepared in the same manner as in Manufacturing Example 9, except that a single-sheet optical film B3 from Manufacturing Example 7 was used. In this way, a long film C3 was obtained in which multiple laminates having the configuration of an adhesive layer / protective layer (PET) / polarizer were arranged at intervals on the long base film.

[0133] [Manufacturing Example 12: Preparation of Long Film C4 Having a Base Film] A long film C4 having a base film was prepared in the same manner as in Manufacturing Example 9, except that a sheet-like optical film B4 from Manufacturing Example 8 was used. In this way, a long film C4 was obtained in which multiple laminates having the configuration of an adhesive layer / second support layer (COP) / second liquid crystal alignment solidification layer were arranged at intervals on the long base film.

[0134] [Manufacturing Example 13: Preparation of Adhesive D1 Constituting the Adhesive Layer] Adhesive D1 was prepared by stirring 60 parts of Ogusol EA-F5710 (manufactured by Osaka Gas Chemical Co., Ltd.), 10 parts of Praxel FA1DDM (manufactured by Daicel Corporation), 20 parts of acryloylmorpholine (trade name "ACMO", manufactured by KJ Chemicals Co., Ltd.), 5 parts of ARFON UP-1190 (manufactured by Toagosei Co., Ltd.), 1 part of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (trade name "Omnirad 819", manufactured by IGM Resins BV Co., Ltd.), 2 parts of 1-hydroxycyclohexyl phenyl ketone (trade name "Omnirad 184", manufactured by IGM Resins BV Co., Ltd.), and 2 parts of diethylthioxanthone (trade name "KAYACURE DETX-S", manufactured by Nippon Kayaku Co., Ltd.) at 50°C for 1 hour.

[0135] [Example 1] (Fabrication of optical stacks) While the long film A1 was conveyed on a roll, adhesive D1 was supplied to the surface of the first liquid crystal alignment solidification layer, and multiple (10) sheets of the second optical film B4 were attached to the long film A1 via the adhesive D1. Each of the multiple sheets of the second optical film B4 was arranged with a gap between them in the longitudinal direction of the long film A1 so that the second liquid crystal alignment solidification layer faced the surface of the first liquid crystal alignment solidification layer. The gap between adjacent second optical films B4 in the longitudinal direction was 3 mm. Next, adhesive D1 was irradiated with ultraviolet light to cure it and form an adhesive layer (thickness 1 μm). The ultraviolet irradiation conditions were: peak illuminance: 1600 mW / cm² 2 Total irradiation dose: 1000 mJ / cm² 2 That's what I decided. In this manner, an optical laminate was fabricated in which multiple laminates having the configuration of an adhesive layer / second optical film B4 (second liquid crystal alignment solidification layer / second support layer) were arranged on a long film A1 (first optical film (first support layer / first liquid crystal alignment solidification layer)). As described above, in the optical laminate, the first surface film of the first optical film is the first liquid crystal alignment solidification layer, and the second surface film of the second optical film is the second liquid crystal alignment solidification layer. The thicknesses of the first surface film and the second surface film are shown in Table 1.

[0136] (Sample preparation) The first support layer of the optical laminate obtained above was peeled off, and the outermost first liquid crystal alignment solidification layer (opposite to the second liquid crystal alignment solidification layer) was bonded to a black acrylic plate via an acrylic adhesive (thickness 10 μm) to obtain an evaluation sample simulating an image display device. The obtained sample was subjected to the evaluation of interference unevenness (linear unevenness) described in (2) above. The results are shown in Table 1.

[0137] [Examples 2-3] An optical laminate and an evaluation sample were obtained in the same manner as in Example 1, except that the long film was changed to the one shown in Table 1. In the sample, the outermost layer was the first liquid crystal alignment solidification layer in Example 2 and the polarizer in Example 3. The obtained sample was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0138] [Comparative Examples 1-3] The second liquid crystal alignment solidification layer of long film A4 was bonded to the surface of the long film shown in Table 1 via adhesive D1 (thickness 1 μm). The bonding was performed by a roll-to-roll process. In Comparative Examples 1 and 2, the surface of the long film to which the second liquid crystal alignment solidification layer was bonded was the first liquid crystal alignment solidification layer, and in Comparative Example 3, it was the polarizer. Next, adhesive D1 was irradiated with ultraviolet light to cure it and form an adhesive layer (1 μm thick). The ultraviolet irradiation conditions were the same as in Example 1. In this way, a long optical laminate having the configuration of a long film (first optical film) / adhesive layer / long film was obtained. Next, evaluation samples were prepared in the same manner as in Example 1. The obtained samples were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0139] [Examples 4-6] While a long carrier film (PET) was conveyed on a roll, an acrylic adhesive (25 μm thick) was placed on the surface of the sheet-like second optical film shown in Table 1. Then, multiple sheets (10 sheets) of the second optical film were attached to the carrier film via this adhesive layer. Each of the multiple sheet-like second optical films was positioned with spacing between them in the longitudinal direction of the carrier film, so that the second support layer side faced the surface of the carrier film. The spacing between adjacent second optical films in the longitudinal direction was 3 mm. Next, while conveying the long films shown in Table 1 on a roll, adhesive D1 was supplied onto the second liquid crystal alignment solidification layer of each of the second optical films described above, and the second optical film (second liquid crystal alignment solidification layer) was attached to the surface of the long film via adhesive D1. In Examples 4 and 5, the surface of the long film to be bonded with the second optical film was the first liquid crystal alignment solidification layer, and in Example 6, it was the polarizer. Next, the adhesive D1 was cured by irradiation with ultraviolet light to form an adhesive layer (thickness 1 μm). The ultraviolet irradiation conditions were the same as in Example 1. In this way, a laminate having a sheet-like second optical film / adhesive layer / carrier film configuration was fabricated on a long film (first optical film) via the adhesive layer. The types and thicknesses of the first surface film in the first optical film and the second surface film in the second optical film are shown in Table 1. An optical laminate was obtained by peeling off the carrier film and adhesive from the resulting laminate. Using the obtained optical laminate, an evaluation sample was prepared in the same manner as in Example 1. The obtained sample was subjected to the evaluation of interference unevenness (linear unevenness) as described in (2) above. The results are shown in Table 1.

[0140] [Examples 7-9] An optical laminate and evaluation samples were obtained in the same manner as in Example 1, except that the long film and the second optical film were changed to those shown in the manufacturing examples in Table 1. The obtained samples were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0141] [Examples 10-12] Optical laminates and evaluation samples were obtained in the same manner as in Examples 4 to 6, except that the long film and the second optical film were changed to those shown in the manufacturing examples in Table 1. The obtained sample image display devices were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0142] [Table 1] [Industrial applicability]

[0143] The optical laminate obtained according to the embodiments of the present invention can be suitably used in optical applications such as optical components and image display devices. [Explanation of Symbols]

[0144] 1 Optical laminate 10. First Optical Film 11. First surface film 100 long rolls of film 101 Base film 20. Second optical film 21. Second surface film 30 Adhesive layer 40 Carrier Film 112 polarizer 121 (1st) Liquid crystal alignment solidification layer 122 (Second) Liquid Crystal Alignment Solidification Layer

Claims

1. A transport process for transporting a long film including the first optical film, A method for manufacturing an optical laminate, comprising a bonding step of bonding a second optical film having a single sheet shape to a first optical film via an adhesive layer composed of a curing adhesive.

2. The method for manufacturing an optical laminate according to claim 1, wherein in the bonding step, a plurality of the second optical films are bonded to the first optical film so that they are spaced apart from each other in the longitudinal direction of the long film.

3. The method for manufacturing an optical laminate according to claim 2, wherein in the bonding step, a plurality of the second optical films are transported by a carrier film and supplied to the first optical film.

4. The method for manufacturing an optical laminate according to claim 2 or 3, wherein the long film includes a first optical film having a long shape.

5. The aforementioned long film, A base film having a long shape, A plurality of first optical films having a sheet-like shape, wherein the plurality of first optical films are positioned on the base film at intervals from each other in the longitudinal direction of the base film, The method for manufacturing an optical laminate according to claim 2 or 3, wherein in the bonding step, each of the plurality of second optical films is bonded to each of the plurality of first optical films.

6. The first optical film comprises a first surface film that comes into contact with the adhesive layer during the bonding process, The second optical film comprises a second surface film that comes into contact with the adhesive layer during the bonding process. The thickness of the adhesive layer is 2 μm or less. The method for manufacturing an optical laminate according to claim 1, wherein the thickness of at least one of the first surface film and the second surface film is 2 μm or less.

7. The method for manufacturing an optical laminate according to claim 6, wherein the thickness of each of the first surface film and the second surface film is 3 μm or less.

8. The method for manufacturing an optical laminate according to claim 6 or 7, wherein at least one of the first surface film and the second surface film is an orientation solidified layer of a liquid crystal compound.

9. The method for manufacturing an optical laminate according to claim 8, wherein the second surface film is an orientation solidified layer of a liquid crystal compound and functions as a λ / 4 plate.

10. The method for manufacturing an optical laminate according to claim 8, wherein the first surface film is an orientation solidified layer of a liquid crystal compound and functions as a λ / 2 plate.

11. The method for manufacturing an optical laminate according to claim 1, wherein the first optical film includes a polarizer.

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