Method for manufacturing an optical stack

Abstract

This invention provides a method for manufacturing an optical laminate capable of suppressing wrinkles, surface scratches, and curling of the optical laminate after it has been cut to product size. The invention involves bonding a first optical film (F1) and a second optical film (F2) that are laterally stretched into a long strip along their length direction using a clamping roller (10) to manufacture an optical laminate (S). Guide rollers (20, 30) are positioned upstream of the clamping roller in the transport direction of the first and / or second optical films, guiding the first and / or second optical films toward the clamping roller. The orientation of the guide rollers is adjusted so that the rotation axis of the guide rollers is inclined from a state parallel to the rotation axis (10L) of the clamping rollers relative to the rotation axis (20L, 30L) of the guide rollers toward the end of the guide rollers that is slack in the width direction away from the first and / or second optical films.

Description

Technical Field

[0001] This invention relates to a method for manufacturing an optical laminate by bonding a first optical film, which is stretched laterally, and a second optical film, which is stretched laterally, together with clamping rollers while conveying them along their length. In particular, this invention relates to a method for manufacturing an optical laminate capable of suppressing wrinkles and surface scratches, and capable of suppressing curling of the optical laminate after it has been cut to product dimensions. Background Technology

[0002] Previously, there were known methods for manufacturing optical laminates by conveying a first optical film and a second optical film in a long strip along the length direction while bonding them together with clamping rollers (see, for example, Patent Document 1).

[0003] In the manufacturing method of the optical laminate (laminate 4 and polarizing plate in Patent Document 1) described above, guide rollers (adjusting rollers 21 and 22 in Patent Document 1) are arranged upstream of the conveying direction of the first optical film (transparent film 1 in Patent Document 1) and the second optical film (polarizing film 2 in Patent Document 1) to guide the first optical film and the second optical film respectively toward the clamping rollers, relative to the clamping rollers (adjusting rollers 11 and 12 in Patent Document 1). At this time, the rotation axis of the guide rollers and the rotation axis of the clamping rollers are generally parallel to each other.

[0004] Here, for example, in the case where the first optical film is a protective film having a substrate layer formed of polyethylene terephthalate, and the first optical film is a film that has been stretched laterally (stretched in a direction orthogonal to the length direction), slack may sometimes occur at any end in the width direction of the first optical film. That is, since the length of the first optical film after being stretched laterally is longer than that of the other end, slack may sometimes occur at the longer end. For example, in the case where the second optical film is a diaphragm formed of polyethylene terephthalate, and the second optical film is a film that has been stretched laterally, slack may also sometimes occur at any end in the width direction of the second optical film.

[0005] According to the research of the present invention, as described above, when slack occurs at the width-direction ends of the first optical film and / or the second optical film, if they are guided by a guide roller having a rotation axis parallel to the rotation axis of the clamping roller and bonded by the clamping roller, wrinkles and surface scratches (marks) may occur on the optical laminate obtained by bonding due to the effect of slack. Furthermore, curling (end warping) may occur on the optical laminate after it has been cut to product size due to the effect of slack.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2014-122967 Summary of the Invention

[0009] The problem that the invention will solve

[0010] The present invention was made to solve the problems of the prior art described above. The objective is to provide a method for manufacturing an optical laminate that can suppress the generation of wrinkles and surface scratches in the optical laminate and suppress the curling of the optical laminate after it is cut to product size.

[0011] Methods for solving problems

[0012] To address the aforementioned problem, the inventors first investigated adjusting the orientation of the guide roller so that its rotation axis is inclined from a state parallel to the rotation axis of the clamping roller towards the end of the guide roller that is closer to the slack side of the first and / or second optical films in the width direction. This is because adjusting the orientation of the guide roller as described above ensures that the path length from the guide roller to the end of the first and / or second optical films on the slack side is longer than the path length on the opposite side. Therefore, when the clamping roller is used to bond the first and second optical films, the effect of slack at the longer end is mitigated by the greater path length.

[0013] It can be seen that by adjusting the posture of the guide roller as described above, the generation of wrinkles and surface scratches in the optical laminate can be suppressed.

[0014] However, it was also learned that curling generated in optical laminates cut to product size could not be adequately suppressed.

[0015] In view of the above research, the inventors further investigated and, contrary to the above research, studied adjusting the posture of the guide roller so that the rotation axis of the guide roller is inclined from a state in which the rotation axis of the guide roller is parallel to the rotation axis of the clamping roller toward the end of the guide roller that produces relaxation in the width direction of the two ends of the first optical film and / or the second optical film.

[0016] This is because it is believed that if the adjustment is made as described above, the path length of the end of the first optical film and / or the second optical film from the guide roller to the clamping roller on the side opposite to the side that produces slack will become longer, so that the length of the end on the opposite side is close to the length of the end on the side that produces slack, and the effect of slack will be mitigated.

[0017] It can be seen that by adjusting the posture of the guide roller as described above, the generation of wrinkles and surface scratches in the optical laminate can be suppressed.

[0018] Furthermore, it was discovered that it can also suppress curling that occurs in optical laminates after they have been cut to product size.

[0019] This invention is based on the insights of the inventors described above.

[0020] In order to solve the aforementioned problem, the present invention provides a method for manufacturing an optical laminate, which is a method for manufacturing an optical laminate by conveying a first optical film and a second optical film that are stretched laterally along the length direction while bonding them together with a clamping roller, thereby manufacturing an optical laminate. The method includes the following steps: relative to the clamping roller, a guide roller is disposed upstream of the conveying direction of the first optical film and / or the second optical film, which guides the first optical film and / or the second optical film toward the clamping roller; the orientation of the guide roller is adjusted so that the rotation axis of the guide roller is inclined from a state where the rotation axis of the guide roller is parallel to the rotation axis of the clamping roller toward the end of the guide roller away from the width direction of the first optical film and / or the second optical film, which is the side where slack is generated.

[0021] In this invention, the phrase "the rotation axis of the guide roller is inclined toward the end of the guide roller that is away from the side of the first optical film and / or the second optical film in the width direction" is not limited to the state in which the end of the rotation axis of the guide roller located at the end of the first optical film and / or the second optical film that is away from ... Furthermore, this concept also includes a state comprising a state in which the end of the rotation shaft of the guide roller located at the end side of the first optical film and / or the second optical film where relaxation occurs moves away from the end side of the first optical film and / or the second optical film where relaxation occurs, and a state in which the end of the rotation shaft of the guide roller located at the end side of the first optical film and / or the second optical film where relaxation occurs moves towards the end side of the first optical film and / or the second optical film where relaxation occurs. In other words, it refers to a state in which the end of the rotation shaft of the guide roller located at the end side of the first optical film and / or the second optical film where relaxation occurs moves away from the end side of the first optical film and / or the second optical film where relaxation occurs.

[0022] Furthermore, in this invention, "being stretched laterally" means being stretched in a direction orthogonal to the length direction. Moreover, "being stretched laterally" is not limited to the case where only lateral stretching is performed, but includes cases where, for example, longitudinal stretching (i.e., longitudinal and transverse stretching) is also performed, or at least lateral stretching is performed.

[0023] According to the present invention, a guide roller for guiding the first optical film and / or the second optical film toward the clamping roller is disposed upstream of the first optical film and / or the second optical film in the conveying direction, relative to the clamping roller. That is, in a first embodiment, a guide roller (hereinafter appropriately referred to as "first guide roller") for guiding the first optical film toward the clamping roller is disposed upstream of the first optical film in the conveying direction. In a second embodiment, a guide roller (hereinafter appropriately referred to as "second guide roller") for guiding the second optical film toward the clamping roller is disposed upstream of the second optical film in the conveying direction. Furthermore, in a third embodiment, guide rollers (first guide roller and second guide roller) for guiding the first optical film and the second optical film toward the clamping roller are respectively disposed upstream of the first optical film and the second optical film in the conveying direction.

[0024] Furthermore, according to the present invention, the orientation of the guide roller is adjusted so that the rotation axis of the guide roller is inclined from a state where the rotation axis of the guide roller is parallel to the rotation axis of the clamping roller toward the end of the guide roller that is slack in the width direction of the first optical film and / or the second optical film. That is, in the first embodiment described above, the orientation of the first guide roller is adjusted so that the rotation axis of the first guide roller is inclined toward the end of the first guide roller that is slack in the width direction of the first optical film. In the second embodiment described above, the orientation of the second guide roller is adjusted so that the rotation axis of the second guide roller is inclined toward the end of the second guide roller that is slack in the width direction of the second optical film. Furthermore, in the third embodiment described above, the orientation of the first guide roller is adjusted so that the rotation axis of the first guide roller is inclined toward the end of the first guide roller that is slack in the width direction of the first optical film, and the orientation of the second guide roller is adjusted so that the rotation axis of the second guide roller is inclined toward the end of the second guide roller that is slack in the width direction of the second optical film.

[0025] According to the present invention, as discovered by the inventors, it is possible to suppress wrinkles and surface scratches in optical laminates, and to suppress curling of optical laminates after they have been cut to product dimensions.

[0026] In this invention, it is preferred that, when both the first optical film and the second optical film have ends that have a loose side, the clamping roller is used to bond the first optical film and the second optical film in such a way that the ends of the first optical film and the second optical film that have a loose side are stacked together.

[0027] According to the preferred method described above, the generation of wrinkles in the optical laminate can be further suppressed.

[0028] The present invention is preferably used, for example, in the case where the first optical film is a protective film having a substrate layer and an adhesive layer, the second optical film is a separator, and the adhesive layer of the first optical film is bonded to the second optical film.

[0029] The optical laminate obtained as described above, for example, after peeling off the separator, is used as a protective cover for the panel by attaching the adhesive layer to the front of the OLED (organic EL) panel or the liquid crystal panel.

[0030] Invention Effects

[0031] According to the present invention, it is possible to suppress the generation of wrinkles and surface scratches in optical laminates, and to suppress the curling of optical laminates after they are cut to product size. Attached Figure Description

[0032] Figure 1 This diagram schematically illustrates the general configuration of a manufacturing apparatus used to perform a conventional method for manufacturing optical laminates.

[0033] Figure 2 It is a cross-sectional view showing the general structure of the optical laminate.

[0034] Figure 3 This diagram schematically illustrates the general configuration of a manufacturing apparatus for performing the manufacturing method of the optical laminate according to the first embodiment.

[0035] Figure 4 This is a schematic diagram illustrating the general configuration of a manufacturing apparatus for performing the manufacturing method of the optical laminate according to the second embodiment.

[0036] Figure 5 This diagram schematically illustrates the general configuration of a manufacturing apparatus for performing the manufacturing method of the optical laminate according to the third embodiment.

[0037] Figure 6 This is a diagram illustrating the method for determining relaxation amount.

[0038] Figure 7 This is a schematic diagram illustrating the general configuration of a manufacturing apparatus used to perform the manufacturing method of the optical laminate S of the reference example.

[0039] Figure 8 This is a diagram illustrating a method for evaluating the curling of optical laminates.

[0040] Figure 9 Evaluation results of optical laminates manufactured by the manufacturing method of Comparative Example 1 and the manufacturing method of Reference Example are shown.

[0041] Figure 10 Evaluation results of optical laminates manufactured by the manufacturing method of Comparative Example 1 and the manufacturing method of Example 1 are shown.

[0042] Figure 11 The evaluation results of the optical laminates manufactured by the manufacturing method of Comparative Example 2 and the manufacturing method of Example 2 are shown.

[0043] Figure 12 The evaluation results of the optical laminates manufactured by the manufacturing method of Comparative Example 3 and the manufacturing method of Example 3 are shown.

[0044] Figure 13 The evaluation results of the optical laminate S manufactured by the manufacturing method of Example 4 are shown. Detailed Implementation

[0045] Hereinafter, the manufacturing method of the optical laminate according to the embodiments of the present invention (first to third embodiments) will be described with appropriate reference to the accompanying drawings.

[0046] <Previous methods for manufacturing optical laminates>

[0047] Before describing the manufacturing method of the optical laminate of this embodiment (hereinafter, the first to third embodiments are collectively referred to as this embodiment), a conventional manufacturing method of optical laminate will first be described.

[0048] Figure 1 This diagram schematically illustrates the general configuration of a manufacturing apparatus used to perform a conventional method for manufacturing optical laminates. Figure 1 (a) is a three-dimensional diagram showing the general structure of the manufacturing apparatus. Figure 1 (b) is a top view showing the general structure of the manufacturing apparatus. Figure 1 In the diagram, X represents the width direction of the optical laminate S, Y represents the length direction of the optical laminate S (the transport direction of the optical laminate S), and Z represents the vertical direction. Additionally, in... Figure 1 In this context, OS means the operating side, which performs various tasks, and DS means the drive side, which has the main drive source. Figure 1In (b), the illustrations of the first optical film F1, the second optical film F2, and the optical laminate S are omitted. The meanings of X, Y, X, OS, and DS will be explained later. Figures 2-7 The same.

[0049] [Optical laminate S]

[0050] First, the structure of the optical laminate S manufactured using a conventional manufacturing apparatus will be described. The optical laminate S manufactured using the manufacturing apparatus of this embodiment and the manufacturing apparatus of the reference example, which will be described later, also have the same structure.

[0051] Figure 2 This is a cross-sectional view (XZ section) showing the approximate structure of the optical laminate S.

[0052] like Figure 2 As shown, the optical laminate S has a structure in which a first optical film F1, serving as a protective film, and a second optical film F2, serving as a separator, are stacked. The first optical film F1 has a substrate layer F11 and an adhesive layer F12, and the adhesive layer F12 is bonded to the second optical film F2, thus the first optical film F1 and the second optical film F2 are stacked.

[0053] (Substrate layer F11 of the first optical film F1)

[0054] The substrate layer F11 can be composed of a single layer or multiple layers. The substrate layer F11 is stretched laterally. Specifically, the substrate layer 11 is stretched both longitudinally and laterally (biaxially). That is, the substrate layer 11 is stretched in both the length and width directions.

[0055] The thickness of the substrate layer F11 can be set to any appropriate thickness according to the application. The thickness of the substrate layer F11 is preferably 20μm to 150μm, more preferably 25μm to 125μm, even more preferably 30μm to 100μm, and particularly preferably 35μm to 75μm.

[0056] The substrate layer F11 is formed of plastic. The substrate layer F11 can be formed of one type of plastic or two or more types of plastic.

[0057] Examples of the aforementioned plastics include polyester resins, polyamide resins, and polyolefin resins. Examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Examples of polyolefin resins include homopolymers of olefin monomers and copolymers of olefin monomers. Specifically, examples of polyolefin resins include homopolymers of polypropylene; block copolymers, random copolymers, and graft copolymers of propylene with ethylene as a copolymer component; reactor TPO; low-density, high-density, linear low-density, and ultra-low-density ethylene polymers; and ethylene-propylene copolymers, ethylene-vinyl acetate copolymers, ethylene-methyl acrylate copolymers, ethylene-ethyl acrylate copolymers, ethylene-butyl acrylate copolymers, ethylene-methacrylic acid copolymers, and ethylene-methyl methacrylate copolymers.

[0058] The substrate layer F11 may contain any suitable additives as needed. Examples of additives that may be included in the substrate layer F11 include antioxidants, UV absorbers, light stabilizers, antistatic agents, fillers, and pigments. The type, quantity, and amount of additives contained in the substrate layer F11 can be appropriately determined according to the purpose. Since the material of the substrate layer F11 is plastic, it is preferable to contain several of the above-mentioned additives for the purpose of preventing deterioration. From the viewpoint of improving durability, antioxidants, UV absorbers, light stabilizers, and fillers are particularly preferred as additives.

[0059] Any suitable antioxidant can be used as the antioxidant. Examples of such antioxidants include phenolic antioxidants, phosphorus-based processing heat stabilizers, lactone-based processing heat stabilizers, sulfur-based heat stabilizers, and phenolic-phosphorus antioxidants. The content of the antioxidant relative to the base resin of the substrate layer F11 (if the substrate layer F11 is a blend, the blend is the base resin) is preferably 1% by weight or less, more preferably 0.5% by weight or less, and even more preferably 0.01% by weight to 0.2% by weight.

[0060] Any suitable ultraviolet absorber can be used as the ultraviolet absorber. Examples of such ultraviolet absorbers include benzotriazole ultraviolet absorbers, triazine ultraviolet absorbers, and benzophenone ultraviolet absorbers. The content ratio of the ultraviolet absorber relative to the base resin forming the substrate layer F11 (if the substrate layer F11 is a blend, the blend is the base resin) is preferably 2% by weight or less, more preferably 1% by weight or less, and even more preferably 0.01% by weight to 0.5% by weight.

[0061] Any suitable light stabilizer can be used as the light stabilizer. Examples of such light stabilizers include hindered amine light stabilizers and benzoic acid ester light stabilizers. The content ratio of the light stabilizer relative to the base resin forming the substrate layer F11 (which is the base resin if the substrate layer F11 is a blend) is preferably 2% by weight or less, more preferably 1% by weight or less, and even more preferably 0.01% by weight to 0.5% by weight.

[0062] Any suitable filler can be used. Examples of such fillers include inorganic fillers. Specifically, examples of inorganic fillers include carbon black, titanium dioxide, and zinc oxide. The filler content relative to the base resin forming the substrate layer F11 (which is the base resin if the substrate layer F11 is a blend) is preferably 20% by weight or less, more preferably 10% by weight or less, and even more preferably 0.01% by weight to 10% by weight.

[0063] Furthermore, as additives, those intended to impart antistatic properties are preferably inorganic, low-molecular-weight, and high-molecular-weight antistatic agents such as surfactants, inorganic salts, polyols, metal compounds, and carbon. In particular, from the viewpoint of preventing contamination and maintaining adhesion, high-molecular-weight antistatic agents and carbon are preferred.

[0064] (Adhesive layer F12 of the first optical film F1)

[0065] The adhesive layer F12 can be composed of a single layer or multiple layers.

[0066] The thickness of the adhesive layer F12 can be set to any suitable thickness according to the application. The thickness of the adhesive layer F12 is preferably 5μm to 50μm, more preferably 6μm to 40μm, further preferably 7μm to 30μm, and particularly preferably 8μm to 20μm.

[0067] As the adhesive layer F12, any suitable adhesive layer can be used. The adhesive layer F12 may include, for example, at least one adhesive selected from acrylic adhesives, polyurethane adhesives, silicone adhesives, and rubber adhesives.

[0068] The adhesive content (e.g., at least one adhesive selected from acrylic adhesives, polyurethane adhesives, silicone adhesives, and rubber adhesives) in the adhesive layer F12 is preferably 96% to 100% by weight, more preferably 97% to 100% by weight, further preferably 98% to 100% by weight, and particularly preferably 99% to 100% by weight. By adjusting the adhesive content in the adhesive layer F12 to the above range, an adhesive layer F12 with excellent anti-residue properties and reprocessability can be produced, for example.

[0069] As an acrylic adhesive, any suitable acrylic adhesive, such as that known acrylic adhesive as described in Japanese Patent Application Publication No. 2013-241606, can be used.

[0070] As a silicone adhesive, any suitable silicone adhesive, such as the silicone adhesive known as described in Japanese Patent Application Publication No. 2014-47280, can be used.

[0071] As a polyester adhesive, any suitable polyester adhesive, such as that known polyester adhesive as described in Japanese Patent Application Publication No. 2013-216875, can be used.

[0072] As a rubber-based adhesive, any suitable rubber-based adhesive, such as that known as those described in Japanese Patent Application Publication No. 2011-236358, can be used.

[0073] As a polyurethane adhesive, any suitable polyurethane adhesive, such as known polyurethane adhesives, can be used.

[0074] As a polyurethane adhesive, it is particularly preferred to contain polyurethane resin.

[0075] The lower limit of the polyurethane resin content in the polyurethane adhesive is preferably 40% by weight or more, more preferably 50% by weight or more, further preferably 55% by weight or more, even more preferably 60% by weight, particularly preferably 65% ​​by weight, and most preferably 70% by weight. The upper limit is preferably 99.999% by weight or less, more preferably 99.99% by weight or less, even more preferably 99.9% by weight or less, even more preferably 99% by weight or less, particularly preferably 95% by weight or less, and most preferably 90% by weight or less. By adjusting the polyurethane resin content in the polyurethane adhesive to the above-mentioned range, for example, a polyurethane adhesive with excellent antistatic properties, excellent residue resistance, and excellent reprocessability can be produced.

[0076] (Second optical film F2)

[0077] The second optical film F2 can be composed of a single layer or multiple layers. The second optical film F2 is stretched laterally. Specifically, the second optical film F2 is stretched both longitudinally and laterally (biaxially). That is, the second optical film F2 is stretched along both the length and width directions.

[0078] The thickness of the second optical film F2 can be set to any appropriate thickness according to the application. The thickness of the second optical film F2 is preferably 20μm to 100μm, more preferably 25μm to 90μm, even more preferably 30μm to 80μm, and particularly preferably 35μm to 70μm.

[0079] The second optical film F2 is a plastic film, preferably coated with a release agent on the adhesive layer F12 side. The second optical film F2 can be formed from one type of plastic or from two or more types of plastic. Specific examples of plastic films include polyethylene terephthalate films, polyethylene films, and polypropylene films. Specific examples of release agents include silicone-based release agents, fluorinated release agents, and long-chain alkyl acrylate release agents.

[0080] [Previous manufacturing equipment]

[0081] Next, the configuration of the conventional manufacturing apparatus will be explained.

[0082] Conventional manufacturing apparatus is an apparatus for manufacturing optical laminates S having the configuration described above.

[0083] like Figure 1 As shown, conventional manufacturing apparatus includes a clamping roller 10 and guide rollers (first guide roller 20 and second guide roller 30).

[0084] The clamping roller 10 consists of a pair of opposing rollers 11 and 12, used to clamp and bond a strip of first optical film F1 and a strip of second optical film F2, which are conveyed along their length, between the pair of rollers 11 and 12. Figure 1 In the example shown, rollers 11 and 12 are arranged opposite each other in the vertical direction (Z direction).

[0085] The first guide roller 20 is positioned relative to the clamping roller 10 in the conveying direction of the first optical film F1. Figure 1 (Illustrated with a hollow arrow in (a)) The upstream side is the roller that guides the first optical film F1 toward the clamping roller 10 (specifically toward the space between a pair of rollers 11, 12).

[0086] The second guide roller 30 is positioned relative to the clamping roller 10 in the conveying direction of the second optical film F2. Figure 1(Illustrated with a hollow arrow in (a)) The upstream side is the roller that guides the second optical film F2 toward the clamping roller 10 (specifically toward the space between a pair of rollers 11 and 12).

[0087] like Figure 1 As shown in (b), in conventional manufacturing apparatuses, the rotation axis (rotation center) 20L of the first guide roller 20 is parallel to the rotation axis (rotation center) 10L of the clamping roller 10. In other words, the rotation axis 10L of the clamping roller 10 is parallel to the width direction (X direction) of the optical laminate S, and the rotation axis 20L of the first guide roller 20 is also parallel to the width direction (X direction) of the optical laminate S. Furthermore, while the rotation axis 10L of the clamping roller 10 actually has a rotation axis parallel to the width direction (X direction) of the optical laminate S for each roller 11, 12, since the rollers 11, 12 are arranged opposite each other in the vertical direction (Z direction), the rotation axis 20L of the first guide roller 20 is parallel to the width direction (X direction) of the optical laminate S. Figure 1 In the top view shown in (b) in the vertical direction (Z direction), it appears to have a common single axis of rotation 10L.

[0088] Similarly, in conventional manufacturing apparatuses, the rotation axis (rotation center) 30L of the second guide roller 30 is parallel to the rotation axis (rotation center) 10L of the clamping roller 10. In other words, the rotation axis 30L of the second guide roller 30 is the same as the rotation axis 10L of the clamping roller 10, and is parallel to the width direction (X direction) of the optical laminate S.

[0089] The first optical film F1 and the second optical film F2 are laterally stretched films, thus sometimes resulting in slack at either end in the width direction. Figure 1 In (a), an example is shown where relaxation occurs on the DS side of the first optical film F1 and on the OS side of the second optical film F2.

[0090] In the event of slack at the width-direction ends of the first optical film F1 and / or the second optical film F2, if... Figure 1 As with conventional manufacturing methods using conventional manufacturing apparatuses, if optical films F1 and F2 are guided by guide rollers 20 and 30 having rotation shafts 20L and 30L parallel to the rotation shaft 10L of the clamping roller 10 and then bonded together with the clamping roller 10, wrinkles S1 and surface scratches (scratches) may occur on the resulting optical laminate S due to the effect of relaxation. Furthermore, curling (end warping) may sometimes occur on the optical laminate S after it has been cut to product size due to the effect of relaxation. The manufacturing apparatus and manufacturing method using this embodiment aim to solve these problems.

[0091] <Method for manufacturing an optical laminate according to the first embodiment>

[0092] Figure 3This diagram schematically illustrates the general configuration of a manufacturing apparatus for performing the manufacturing method of the optical laminate according to the first embodiment. Figure 3 (a) is a three-dimensional diagram showing the general structure of the manufacturing apparatus. Figure 3 (b) is a top view showing the general structure of the manufacturing apparatus. Figure 3 In (b), the illustrations of the first optical film F1, the second optical film F2, and the optical laminate S are omitted.

[0093] like Figure 3 As shown, the manufacturing apparatus of the first embodiment is also similar to... Figure 1 The conventional manufacturing apparatus shown has the same clamping roller 10 and guide rollers (first guide roller 20, second guide roller 30).

[0094] The clamping roller 10 consists of a pair of opposing rollers 11 and 12, used to clamp and bond a strip of first optical film F1 and a strip of second optical film F2, which are conveyed along their length, between the pair of rollers 11 and 12. Figure 3 In the example shown, rollers 11 and 12 are arranged opposite each other in the vertical direction (Z direction).

[0095] The first guide roller 20 is positioned upstream of the first optical film F1 in the conveying direction relative to the clamping roller 10, and is a roller that guides the first optical film F1 toward the clamping roller 10 (specifically toward the space between a pair of rollers 11 and 12).

[0096] The second guide roller 30 is positioned upstream of the conveying direction of the second optical film F2 relative to the clamping roller 10, and is a roller that guides the second optical film F2 toward the clamping roller 10 (specifically, toward the space between a pair of rollers 11 and 12).

[0097] The above description constitutes and Figure 1 The situation is the same as that of conventional manufacturing equipment.

[0098] However, in the manufacturing apparatus of the first embodiment, the orientation of the first guide roller 20 is... Figure 1 The orientation of the first guide roller 20 shown is different. For example... Figure 3 As shown in (b), in the manufacturing apparatus of the first embodiment, the rotation axis 20L of the first guide roller 20 is in a state parallel to the rotation axis 10L of the clamping roller 10. Figure 3 (b) is shown in a slanted state (illustrated by dashed lines).

[0099] Specifically, in Figure 3 In the example shown in (a), relaxation occurs only on the DS side of the first optical film F1 (no relaxation occurs on the second optical film F2). Therefore, as Figure 3As shown in (b), in the manufacturing apparatus of the first embodiment, the posture of the first guide roller 20 is adjusted so that the rotation axis 20L of the first guide roller 20 is inclined from a state parallel to the rotation axis 10L of the clamping roller 10 toward the end of the first guide roller 20 away from the DS side where relaxation occurs in the first optical film F1. More specifically, it becomes the following state: Although according to Figure 3 From (a), it can be seen that the first optical film F1 (in) Figure 3 (Figure omitted in (b)) is located below the first guide roller 20. Figure 3 (b) on the underside of the paper), but as Figure 3 As shown in (b), the end of the rotation shaft 20L of the first guide roller 20 located on the DS side of the first optical film F1, which is the end where relaxation occurs, moves away from the end of the first optical film F1 on the DS side where relaxation occurs. Figure 3 (b) shows that the Y direction moved upwards by ΔY1.

[0100] Furthermore, as described above, in order to facilitate the movement of the end of the rotation shaft 20L of the first guide roller 20, a tension roller can be used as the first guide roller 20. The tension roller is a roller comprising: a roller body; and a fixed support for one end of the roller body (…). Figure 3 The example shown is the support unit at the end of the OS side; and the single-shaft stage, the other end of the support roller body ( Figure 3 The example shown is the end on the DS side), and in the initial state (parallel to the rotation axis 10L of the clamping roller 10), in a direction orthogonal to the rotation axis 20L ( Figure 3 In the example shown, the movement is in the Y direction. By moving this single-axis stage, the other end of the roller body can be easily moved. That is, the end of the rotation axis 20L of the first guide roller 20 can be easily moved.

[0101] like Figure 3 As shown in (a), when slack occurs at the DS side end of the first optical film F1, in the manufacturing method of the first embodiment, the first optical film F1 is guided by a first guide roller 20 having a rotation shaft 20L that is adjusted to be tilted in a specific direction relative to the rotation shaft 10L of the clamping roller 10, and is bonded using the clamping roller 10, thereby suppressing wrinkles S1 of the optical laminate S obtained by bonding (see reference). Figure 1 It can prevent the formation of surface scratches and suppress the curling of the optical laminate S after it is cut to product size.

[0102] <Method for manufacturing an optical laminate according to the second embodiment>

[0103] Figure 4This is a schematic diagram illustrating the general configuration of a manufacturing apparatus for performing the manufacturing method of the optical laminate according to the second embodiment. Figure 4 (a) is a three-dimensional diagram showing the general structure of the manufacturing apparatus. Figure 4 (b) is a top view showing the general structure of the manufacturing apparatus. Figure 4 In (b), the illustrations of the first optical film F1, the second optical film F2, and the optical laminate S are omitted.

[0104] like Figure 4 As shown, the manufacturing apparatus of the second embodiment is also similar to... Figure 3 The manufacturing apparatus shown is the same as that of the first embodiment, and includes a clamping roller 10 and guide rollers (first guide roller 20 and second guide roller 30). Hereinafter, the differences from the manufacturing apparatus of the first embodiment will be mainly described, and the similarities will be omitted as appropriate.

[0105] In the manufacturing apparatus of the second embodiment, the orientation of the second guide roller 30 is... Figure 1 The second guide roller 30 shown has a different orientation. For example... Figure 4 As shown in (b), in the apparatus of the second embodiment, the rotation axis 30L of the second guide roller 30 is parallel to the rotation axis 10L of the clamping roller 10. Figure 4 (b) is shown in a slanted state (illustrated by dashed lines).

[0106] Specifically, in Figure 4 In the example shown in (a), relaxation occurs only on the OS side of the second optical film F2 (no relaxation occurs in the first optical film F1). Therefore, as Figure 4 As shown in (b), in the manufacturing apparatus of the second embodiment, the posture of the second guide roller 30 is adjusted so that the rotation axis 30L of the second guide roller 30 is inclined from a state parallel to the rotation axis 10L of the clamping roller 10 toward the end of the second guide roller 30 away from the OS side where relaxation is generated on the second optical film F2. More specifically, it becomes the following state: Although according to Figure 4 From (a), we can see that the second optical film F2 ( Figure 4 (Figure omitted in (b)) is located below the second guide roller 30. Figure 4 (b) on the underside of the paper), but as Figure 4 As shown in (b), the end of the rotation shaft 30L of the second guide roller 30 located on the end side of the second optical film F2 where the OS side is relaxed moves away from the end side of the second optical film F2 where the OS side is relaxed. Figure 4 (b) shows the state where the Y direction is upward, and the state has shifted by ΔY2.

[0107] Furthermore, as described above, in order to facilitate the movement of the end of the rotation shaft 30L of the second guide roller 30, a tension roller can be used as the second guide roller 30. The tension roller is a roller comprising: a roller body; and a fixed support for one end of the roller body (…). Figure 4 The example shown is the support unit at the end of the DS side; and the single-shaft stage, supporting the other end of the roller body ( Figure 4 The example shown is the end on the OS side), and in the initial state (parallel to the rotation axis 10L of the clamping roller 10), in a direction orthogonal to the rotation axis 30L ( Figure 4 In the example shown, the movement is in the Y direction. By moving this single-axis stage, the other end of the roller body can be easily moved. That is, the end of the rotation shaft 30L of the second guide roller 30 can be easily moved.

[0108] like Figure 4 As shown in (a), when slack occurs at the OS side end of the second optical film F2, in the manufacturing method of the second embodiment, the second optical film F2 is guided by a second guide roller 30 having a rotation shaft 30L that is adjusted to be tilted in a specific direction relative to the rotation shaft 10L of the clamping roller 10, and is bonded using the clamping roller 10, thereby suppressing wrinkles S1 of the optical laminate S obtained by bonding (see reference). Figure 1 It can prevent the formation of surface scratches and suppress the curling of the optical laminate S after it is cut to product size.

[0109] <Method for manufacturing an optical laminate according to the third embodiment>

[0110] Figure 5 This diagram schematically illustrates the general configuration of a manufacturing apparatus for performing the manufacturing method of the optical laminate according to the third embodiment. Figure 5 (a) is a three-dimensional diagram showing the general structure of the manufacturing apparatus. Figure 5 (b) is a top view showing the general structure of the manufacturing apparatus. Figure 5 In (b), the illustrations of the first optical film F1, the second optical film F2, and the optical laminate S are omitted.

[0111] like Figure 5 As shown, the manufacturing apparatus of the third embodiment is also similar to... Figure 3 The manufacturing apparatus of the first embodiment shown Figure 4 The manufacturing apparatus shown in the second embodiment is the same as that of the first embodiment, and includes a clamping roller 10 and guide rollers (first guide roller 20 and second guide roller 30). Hereinafter, the differences from the manufacturing apparatus of the first embodiment and the second embodiment will be mainly described, and the similarities will be omitted as appropriate.

[0112] In the manufacturing apparatus of the third embodiment, the posture of the first guide roller 20 is related to... Figure 1 The orientation of the first guide roller 20 shown is different. Furthermore, the orientation of the second guide roller 30 is different from... Figure 1 The second guide roller 30 shown has a different orientation. For example... Figure 5 As shown in (b), in the apparatus of the third embodiment, the rotation axis 20L of the first guide roller 20 is in a state parallel to the rotation axis 10L of the clamping roller 10. Figure 5 (b) is shown in a tilted state (illustrated with dashed lines). Furthermore, in the manufacturing apparatus of the third embodiment, the rotation axis 30L of the second guide roller 30 is parallel to the rotation axis 10L of the clamping roller 10. Figure 5 (b) is shown in a slanted state (illustrated by dashed lines).

[0113] Specifically, in Figure 5 In the example shown in (a), a slack occurs between the DS side of the first optical film F1 and the OS side of the second optical film F2. Therefore, as Figure 5 As shown in (b), in the manufacturing apparatus of the third embodiment, the posture of the first guide roller 20 is adjusted so that the rotation axis 20L of the first guide roller 20 is inclined from a state where the rotation axis 20L of the first guide roller 20 is parallel to the rotation axis 10L of the clamping roller 10 towards the end of the first guide roller 20 away from the DS side of the first optical film F1 where relaxation occurs. Furthermore, in the manufacturing apparatus of the third embodiment, the posture of the second guide roller 30 is adjusted so that the rotation axis 30L of the second guide roller 30 is inclined from a state where the rotation axis 30L of the second guide roller 30 is parallel to the rotation axis 10L of the clamping roller 10 towards the end of the second guide roller 30 away from the OS side of the second optical film F2 where relaxation occurs. More specifically, it becomes the following state: Although according to Figure 5 From (a), we can see that the first optical film F1 ( Figure 5 (Figure omitted in (b)) is located below the first guide roller 20. Figure 5 (b) on the underside of the paper), but as Figure 5 As shown in (b), the end of the rotation shaft 20L of the first guide roller 20 located on the DS side of the first optical film F1, which is the end where relaxation occurs, moves away from the end of the first optical film F1 on the DS side where relaxation occurs. Figure 5 (b) shows a movement of ΔY1 upwards in the Y direction. Furthermore, it becomes the following state: Although according to... Figure 5 From (a), we can see that the second optical film F2 ( Figure 5 (Figure omitted in (b)) is located below the second guide roller 30. Figure 5 (b) on the underside of the paper), but as Figure 5As shown in (b), the end of the rotation shaft 30L of the second guide roller 30 located on the end side of the second optical film F2 where the OS side is relaxed moves away from the end side of the second optical film F2 where the OS side is relaxed. Figure 5 (b) shows that the Y direction moved upwards by ΔY2.

[0114] Furthermore, as described above, in order to facilitate the movement of the ends of the rotation shaft 20L of the first guide roller 20 and the rotation shaft 30L of the second guide roller 30, tension rollers can be used as the first guide roller 20 and the second guide roller 30. Details regarding the tension rollers are as described previously.

[0115] like Figure 5 As shown in (a), when slack occurs at the DS-side end of the first optical film F1 and the OS-side end of the second optical film F2, in the manufacturing method of the third embodiment, the first optical film F1 is guided by a first guide roller 20 having a rotation shaft 20L adjusted to be tilted in a specific direction relative to the rotation shaft 10L of the clamping roller 10, and the second optical film F2 is guided by a second guide roller 30 having a rotation shaft 30L adjusted to be tilted in a specific direction relative to the rotation shaft 10L of the clamping roller 10, and is bonded using the clamping roller 10, thereby suppressing wrinkles S1 in the optical laminate S obtained by bonding (see reference). Figure 1 It can prevent the formation of surface scratches and suppress the curling of the optical laminate S after it is cut to product size.

[0116] In the above-described embodiment, the case where the first optical film F1 is a protective film and the second optical film F2 is a diaphragm was used as an example, but the present invention is not limited thereto. For example, it can be applied to various combinations of the first optical film F1 and the second optical film F2, such as the case where the first optical film F1 is a polarizing film with a surface protective film and the second optical film F2 is a diaphragm.

[0117] Furthermore, in this embodiment, the case of configuring both the first guide roller 20 and the second guide roller 30 is described as an example. However, if relaxation occurs only in one of the first optical film F1 and the second optical film F2, then only the guide roller corresponding to the optical film that has relaxed can be configured (for example, if relaxation occurs only in the first optical film F1, then only the first guide roller 20 can be configured).

[0118] Furthermore, in this embodiment, the example described is that the end of the rotation shaft 20L of the first guide roller 20 (or the rotation shaft 30L of the second guide roller 30) located at the end side of the first optical film F1 (or the second optical film F2) on the side where relaxation occurs is moved away from the end side of the first optical film F1 (or the second optical film F2) on the side where relaxation occurs, but the present invention is not limited to this. It is also possible to adjust the end of the rotation shaft 20L of the first guide roller 20 (or the rotation shaft 30L of the second guide roller 30) located at the end side of the first optical film F1 (or the second optical film F2) on the side opposite to the end side where relaxation occurs to move towards the end side of the first optical film F1 (or the second optical film F2) on the side opposite to the end side where relaxation occurs. For example, in the first embodiment, as... Figure 3 As shown, the first guide roller 20 is adjusted so that the end of the rotation shaft 20L (the end on the DS side) moves away from the end of the first optical film F1 that produces relaxation on the DS side. However, it is not limited to this. It can also be adjusted so that the end of the rotation shaft 20L (the end on the OS side) moves towards the end of the first optical film F1 on the OS side, which is opposite to the end of the end that produces relaxation on the DS side.

[0119] Hereinafter, an example will be described of the results of an experiment conducted using the manufacturing method of the optical laminate S according to this embodiment (Examples 1 to 3), the manufacturing method of the optical laminate S according to comparative examples (Comparative Examples 1 to 3), and the manufacturing method of the optical laminate S according to reference examples to manufacture optical laminate S.

[0120] <Example 1>

[0121] An acrylic adhesive is applied to a strip of substrate layer F11 (75 μm thick) made of biaxially stretched polyethylene terephthalate using an impregnation roller to achieve a dried thickness of 50 μm, and then allowed to dry to form an adhesive layer F12. This produces a protective film, namely the strip-shaped first optical film F1, which consists of the substrate layer F11 and the adhesive layer F12.

[0122] On the first optical film F1, relaxation was generated on the DS side, with a relaxation amount ΔS1 of 3 mm (refer to...). Figure 3 (a)

[0123] Figure 6 This is a diagram illustrating the method for determining the relaxation amount ΔS1.

[0124] When measuring the relaxation amount ΔS1, the first optical film F1 is first erected under tension between specified rollers. In this state, as... Figure 6As shown, the position of the laser distance meter 40 in the width direction (X direction) of the first optical film F1 is changed, and the distance from the surface of the first optical film F1 is measured using the laser distance meter 40 at each position. Then, the difference between the measured maximum and minimum distances is calculated as the relaxation amount ΔS1. The method for measuring the relaxation amount ΔS2 of the second optical film F2, which will be described later, is the same.

[0125] On the other hand, a 25μm thick diaphragm, namely the long strip of second optical film F2, is produced by coating one side of a biaxially stretched polyethylene terephthalate film with an organosilicon-based striping agent.

[0126] The first optical film F1 and the second optical film F2, which are manufactured as described above, are guided by the first guide roller 20 and the second guide roller 30 respectively in the clamping roller 10 so that the adhesive layer F12 of the first optical film F1 and the surface coating of the second optical film F2 are facing each other. They are then bonded together by the clamping roller 10 to produce an optical laminate S.

[0127] At this time, the end of the rotating shaft 20L of the first guide roller 20 (the end on the DS side) is pre-adjusted to move away from the end on the DS side of the first optical film F1 that generates relaxation. Figure 3 (b) shows a state where the Y direction is upward and the object has moved 5 mm (ΔY1 = +5 mm, refer to...). Figure 3 (a) Therefore, the rotation axis 20L of the first guide roller 20 is tilted by 0.15° from a state parallel to the rotation axis 10L of the clamping roller 10. The rotation axis 30L of the second guide roller 30 remains parallel to the rotation axis 10L of the clamping roller 10. Furthermore, in this specification, ΔY1 is used to represent the direction away from the first optical film F1 in a positive value and the direction approaching the first optical film F1 in a negative value.

[0128] <Example 2>

[0129] Similar to Example 1, an acrylic adhesive was applied to a strip of biaxially stretched polyethylene terephthalate substrate layer F11 (75 μm thick) using an impregnation roller to achieve a dried thickness of 50 μm, and then allowed to dry to form an adhesive layer F12. This produced a protective film, namely the strip of first optical film F1, consisting of a substrate layer F11 and an adhesive layer F12.

[0130] On the other hand, a 25μm thick diaphragm, namely the long strip of second optical film F2, is produced by coating one side of a biaxially stretched polyethylene terephthalate film with an organosilicon-based striping agent.

[0131] On the second optical film F2, relaxation occurs on the OS side, with a relaxation amount ΔS2 of 3 mm (refer to...). Figure 4(a)

[0132] Furthermore, the optical film that produces relaxation (the second optical film F2 in Example 2), the end of the side where relaxation occurs (the OS side in Example 2), and the relaxation amount (3 mm in Example 2) are different from those in Example 1, which is believed to be due to the following reasons.

[0133] Typically, biaxially stretched strips of polyethylene terephthalate (PET) films are manufactured by sequentially performing melt extrusion, longitudinal stretching, and transverse stretching. Even with the same raw materials, differences in the molecular weight distribution of the resin can lead to variations in melt viscosity, potentially causing variations in the film thickness distribution during melt extrusion. Therefore, to achieve a uniform thickness distribution after biaxial stretching, feedback control is typically implemented during melt extrusion to adjust the thickness. However, this results in subtle variations in the stretch ratio implemented in the width direction. It is believed that this is why, even with PET films made from the same raw materials, differences can occur in the resulting relaxed optical film, the relaxed end, and the amount of relaxation. This is also the case in Examples 3 and 4.

[0134] The first optical film F1 and the second optical film F2, which are manufactured as described above, are guided by the first guide roller 20 and the second guide roller 30 respectively in the clamping roller 10 so that the adhesive layer F12 of the first optical film F1 and the surface coating of the second optical film F2 are facing each other. They are then bonded together by the clamping roller 10 to produce an optical laminate S.

[0135] At this time, the end of the rotating shaft 30L of the second guide roller 30 (the end on the OS side) is pre-adjusted to move away from the end on the OS side of the second optical film F2 that generates relaxation. Figure 4 (b) shows a state where the Y direction is upward and the object has moved 5mm (ΔY2=+5mm, refer to...). Figure 4 (a) Therefore, the rotation axis 30L of the second guide roller 30 is tilted by 0.15° from a state parallel to the rotation axis 10L of the clamping roller 10. The rotation axis 20L of the first guide roller 20 remains parallel to the rotation axis 10L of the clamping roller 10. Furthermore, in this specification, ΔY2 is used to represent the direction away from the second optical film F2 in a positive value and the direction approaching the second optical film F2 in a negative value.

[0136] <Example 3>

[0137] Similar to Example 1, an acrylic adhesive was applied to a strip of biaxially stretched polyethylene terephthalate substrate layer F11 (75 μm thick) using an impregnation roller to achieve a dried thickness of 50 μm, and then allowed to dry to form an adhesive layer F12. This produced a protective film, namely the strip of first optical film F1, consisting of a substrate layer F11 and an adhesive layer F12.

[0138] On the first optical film F1, relaxation is generated on the DS side, with a relaxation amount ΔS1 of 7 mm (reference). Figure 5 (a)

[0139] On the other hand, a 25μm thick diaphragm, namely the long strip of second optical film F2, is produced by coating one side of a biaxially stretched polyethylene terephthalate film with an organosilicon-based striping agent.

[0140] On the second optical film F2, relaxation occurs on the OS side, with a relaxation amount ΔS2 of 5 mm (refer to...). Figure 5 (a)

[0141] The first optical film F1 and the second optical film F2, which are manufactured as described above, are guided by the first guide roller 20 and the second guide roller 30 respectively in the clamping roller 10 so that the adhesive layer F12 of the first optical film F1 and the surface coating of the second optical film F2 are facing each other. They are then bonded together by the clamping roller 10 to produce an optical laminate S.

[0142] At this time, the end of the rotating shaft 20L of the first guide roller 20 (the end on the DS side) is pre-adjusted to move away from the end on the DS side of the first optical film F1 that generates relaxation. Figure 5 (b) shows a state where the Y direction is upward and the object has moved 8 mm (ΔY1 = +8 mm, refer to...). Figure 5 (a)). Therefore, the rotation axis 20L of the first guide roller 20 is tilted by 0.25° relative to the rotation axis 10L of the clamping roller 10. Furthermore, the end of the rotation axis 30L of the second guide roller 30 (the end on the OS side) is adjusted to move away from the end on the OS side of the second optical film F2 where relaxation occurs. Figure 5 (b) shows a state where the Y direction is upward and the object has moved 3 mm (ΔY2 = +3 mm, refer to...). Figure 5 (a) As a result, the rotation axis 30L of the second guide roller 30 is tilted by 0.09° relative to the rotation axis 10L of the clamping roller 10.

[0143] Furthermore, in Example 2, when the relaxation amount ΔS2 = 3 mm, it was adjusted to ΔY2 = +5 mm; in Example 3, when the relaxation amount ΔS2 = 5 mm, it was adjusted to ΔY2 = +3 mm. That is, when the relaxation amount ΔS2 is small (Example 2), the movement amount ΔY2 is adjusted to be larger. This is because, as a... Figure 6 The relaxation amount ΔS2 measured by the method shown is smaller in Example 2, but the relaxation distribution in the width direction of the second optical film F2 is larger in Example 2. Thus, the movement amount ΔY1 (tilt angle of the rotation axis 20L of the first guide roller 20) at the end of the rotation axis 20L of the first guide roller 20 and the movement amount ΔY2 (tilt angle of the rotation axis 30L of the second guide roller 30) at the end of the rotation axis 30L of the second guide roller 30 are adjusted to appropriate values ​​not only taking into account the relaxation amount ΔS1 of the first optical film F1 and the relaxation amount ΔS2 of the second optical film F2, but also taking into account the relaxation distribution in the width direction.

[0144] <Example 4>

[0145] Similar to Example 1, an acrylic adhesive was applied to a strip of biaxially stretched polyethylene terephthalate substrate layer F11 (75 μm thick) using an impregnation roller to achieve a dried thickness of 50 μm, and then allowed to dry to form an adhesive layer F12. This produced a protective film, namely the strip of first optical film F1, consisting of a substrate layer F11 and an adhesive layer F12.

[0146] On the first optical film F1, relaxation is generated on the OS side, and the relaxation amount ΔS1 is 3mm.

[0147] On the other hand, a 25μm thick diaphragm, namely the long strip of second optical film F2, is produced by coating one side of a biaxially stretched polyethylene terephthalate film with an organosilicon-based striping agent.

[0148] On the second optical film F2, relaxation is generated on the OS side, and the relaxation amount ΔS2 is 3mm.

[0149] The first optical film F1 and the second optical film F2, manufactured as described above, are guided by the first guide roller 20 and the second guide roller 30 respectively in a clamping roller 10 such that the adhesive layer F12 of the first optical film F1 and the surface-coated part of the second optical film F2 face each other. They are then bonded together using the clamping roller 10 to create an optical laminate S. As mentioned above, both the first optical film F1 and the second optical film F2 are relaxed on the same OS side. Therefore, the optical laminate S is formed by laminating the relaxed side of the first optical film F1 and the relaxed side of the second optical film F2.

[0150] At this time, the end of the rotation shaft 20L of the first guide roller 20 (the end on the OS side) is pre-adjusted to move 5 mm (ΔY1 = +5 mm) away from the end of the first optical film F1 that generates relaxation on the OS side. As a result, the rotation shaft 20L of the first guide roller 20 is tilted by 0.15° from a state parallel to the rotation shaft 10L of the clamping roller 10. Similarly, the end of the rotation shaft 30L of the second guide roller 30 is pre-adjusted to move 5 mm (the end on the OS side) away from the end of the second optical film F2 that generates relaxation on the OS side (ΔY2 = +5 mm). As a result, the rotation shaft 30L of the second guide roller 30 is tilted by 0.15° from a state parallel to the rotation shaft 10L of the clamping roller 10.

[0151] <Comparative Example 1>

[0152] Similar to Example 1, the first optical film F1 with a relaxation amount ΔS1 = 3 mm and the second optical film F2 are guided by the first guide roller 20 and the second guide roller 30 respectively in a way that the adhesive layer F12 of the first optical film F1 and the surface coating of the second optical film F2 are facing each other in the clamping roller 10, and then bonded by the clamping roller 10 to produce an optical laminate S.

[0153] At this time, unlike in Embodiment 1, the rotation axis 20L of the first guide roller 20 is still parallel to the rotation axis 10L of the clamping roller 10.

[0154] <Comparative Example 2>

[0155] Similar to Example 2, the first optical film F1 and the second optical film F2 with a relaxation amount ΔS2 = 3mm are guided by the first guide roller 20 and the second guide roller 30 respectively in the clamping roller 10 so that the adhesive layer F12 of the first optical film F1 and the surface coating of the second optical film F2 are facing each other. They are then bonded together using the clamping roller 10 to produce an optical laminate S.

[0156] At this time, unlike in Embodiment 2, the rotation axis 30L of the second guide roller 30 is still parallel to the rotation axis 10L of the clamping roller 10.

[0157] <Comparative Example 3>

[0158] Similar to Example 3, a first optical film F1 with a relaxation amount ΔS1 = 7 mm and a second optical film F2 with a relaxation amount ΔS2 = 5 mm are guided by a first guide roller 20 and a second guide roller 30 respectively in a clamping roller 10 such that the adhesive layer F12 of the first optical film F1 and the surface coating of the second optical film F2 face each other. They are then bonded together using the clamping roller 10 to create an optical laminate S.

[0159] At this time, unlike in Embodiment 3, the rotation axis 20L of the first guide roller 20 and the rotation axis 30L of the second guide roller 30 are still parallel to the rotation axis 10L of the clamping roller 10.

[0160] <Reference Example>

[0161] Figure 7 This is a schematic diagram illustrating the general configuration of a manufacturing apparatus used to perform the manufacturing method of the optical laminate S of the reference example. Figure 7 (a) is a three-dimensional diagram showing the general structure of the manufacturing apparatus. Figure 7 (b) is a top view showing the general structure of the manufacturing apparatus. Figure 7 In (b), the illustrations of the first optical film F1, the second optical film F2, and the optical laminate S are omitted.

[0162] like Figure 7 As shown, the manufacturing apparatus of the reference example is also similar to... Figure 3 The manufacturing apparatus shown in the first embodiment (Example 1) is the same, and includes a clamping roller 10 and guide rollers (first guide roller 20 and second guide roller 30).

[0163] In the reference example, similar to Example 1, the relaxation amount ΔS1 = 3 mm (refer to Example 1). Figure 7 The first optical film F1 and the second optical film F2 of (a) are guided by the first guide roller 20 and the second guide roller 30 respectively in a manner in which the adhesive layer F12 of the first optical film F1 and the surface coating of the second optical film F2 are facing each other in the clamping roller 10, and are bonded together by the clamping roller 10 to produce an optical laminate S.

[0164] At this time, unlike in Embodiment 1, the end of the rotation shaft 20L of the first guide roller 20 (the end on the DS side) is pre-adjusted towards the end of the first optical film F1 on the DS side where relaxation occurs. Figure 7 (b) shows a state where the Y direction is downwards, and the object has moved 5 mm (ΔY1 = -5 mm, refer to...). Figure 7 (a)

[0165] <Evaluation Content and Results>

[0166] The wrinkles, surface scratches, and curling of the optical laminates S manufactured by the manufacturing methods of Examples 1 to 4, the comparative examples, and the reference examples described above were evaluated.

[0167] For wrinkles, visual inspection is used to confirm their presence.

[0168] Regarding surface scratches, the number of surface scratches generated per unit length of the optical laminate S was determined.

[0169] Figure 8 This is a diagram illustrating a method for evaluating the curling of an optical laminate S. Figure 8 (a) is a top view of the optical laminate S after it has been cut to product size. Figure 8 (b) is a graph illustrating the curl value C.

[0170] When evaluating the curling of the optical laminate S, such as Figure 8 As shown in (a), the long strip of optical laminate S is cut to product size. Figure 8 In the example shown in (a), it is cut into dimensions of 1000 mm in the width direction (X direction) and 1500 mm in the length direction (Y direction). Then, as... Figure 8 As shown in (b), so that Figure 8 In (a), the warped corners of the cut optical laminate S, enclosed by dashed lines, are oriented upwards in the vertical direction (Z direction). The cut optical laminate S is placed on a flat stage 40, and the vertical distance from the upper surface of the stage 40 to the upper warped end ST is measured for each corner. The vertical distance from the upper surface of the stage 40 to the upper warped end ST is measured by visually reading the scale of a vertically extending ruler erected near the warped area. This measured distance is evaluated as a curl value C, indicating the degree of curl.

[0171] Figure 9 The evaluation results of the optical laminate S manufactured by the manufacturing method of Comparative Example 1 and the manufacturing method of Reference Example are shown. Figure 9 (a) shows the relaxation amounts of the first optical film F1 and the second optical film F2, which are used in Comparative Example 1 and Reference Example. Figure 9 (b) shows the amount of movement of the first guide roller 20 and the second guide roller 30 and the evaluation results regarding wrinkles, surface scratches and curling of the optical laminate S.

[0172] exist Figure 9In the "Wrinkles of Optical Laminates" column, "◎" indicates that wrinkles are completely invisible on the optical laminate S, "〇" indicates that wrinkles are almost invisible on the optical laminate S, and "×" indicates that wrinkles are clearly visible on the optical laminate S. Similarly, in the "Surface Scratches of Optical Laminates" column, "〇" indicates that there are 5 or fewer surface scratches per 1m of the optical laminate S, and "×" indicates that there are 6 or more surface scratches per 1m of the optical laminate S. Furthermore, in the "Curling of Optical Laminates" column, "〇" indicates that the curling value C at all four corners of the optical laminate S after being cut to product size is 5mm or less, and "×" indicates that one of the curling values ​​C at the four corners of the optical laminate S after being cut to product size exceeds 5mm. The meanings of "〇" and "×" in each column will be explained later. Figures 10-13 The same.

[0173] like Figure 9 As shown, in the manufacturing method of Comparative Example 1, wrinkles and surface scratches of the optical laminate S are marked as "×" on the DS side, but in the manufacturing method of the Reference Example, the improvement is "〇". However, it can be seen that regarding curling, both the OS side and the DS side are still marked as "×", and no improvement has been made.

[0174] Figure 10 The evaluation results of the optical laminate S manufactured by the manufacturing method of Comparative Example 1 and the manufacturing method of Example 1 are shown. Figure 10 (a) shows the relaxation amount of the first optical film F1 and the second optical film F2 used in Comparative Example 1 and Example 1. Figure 10 (b) shows the amount of movement of the first guide roller 20 and the second guide roller 30 and the evaluation results regarding wrinkles, surface scratches and curling of the optical laminate S.

[0175] like Figure 10 As shown, in the manufacturing method of Comparative Example 1, wrinkles and surface scratches of the optical laminate S are marked as "×" on the DS side, but in the manufacturing method of Example 1, the improvement is "〇". Furthermore, it is also evident that curling is improved to "〇" on both the OS and DS sides.

[0176] Figure 11 The evaluation results of the optical laminate S manufactured by the manufacturing method of Comparative Example 2 and the manufacturing method of Example 2 are shown. Figure 11 (a) shows the relaxation amount of the first optical film F1 and the second optical film F2 used in Comparative Example 2 and Example 2. Figure 11 (b) shows the amount of movement of the first guide roller 20 and the second guide roller 30 and the evaluation results regarding wrinkles, surface scratches and curling of the optical laminate S.

[0177] like Figure 11 As shown, in the manufacturing method of Comparative Example 2, wrinkles, surface scratches and curling of the optical laminate S on the OS side are marked with "×", but in the manufacturing method of Example 2, all of them are improved to "0".

[0178] Figure 12 The evaluation results of the optical laminate S manufactured by the manufacturing method of Comparative Example 3 and the manufacturing method of Example 3 are shown. Figure 12 (a) shows the relaxation amount of the first optical film F1 and the second optical film F2 used in Comparative Example 3 and Example 3. Figure 12 (b) shows the amount of movement of the first guide roller 20 and the second guide roller 30 and the evaluation results regarding wrinkles, surface scratches and curling of the optical laminate S.

[0179] like Figure 12 As shown, in the manufacturing method of Comparative Example 3, wrinkles, surface scratches and curling of the optical laminate S are marked as "×" on both the OS side and the DS side, but in the manufacturing method of Example 3, all of them are improved to "0".

[0180] Figure 13 The evaluation results of the optical laminate S manufactured by the manufacturing method of Example 4 are shown. Figure 13 (a) shows the relaxation amount of the first optical film F1 and the second optical film F2 used in Example 4. Figure 13 (b) shows the amount of movement of the first guide roller 20 and the second guide roller 30 and the evaluation results regarding wrinkles, surface scratches and curling of the optical laminate S.

[0181] like Figure 13 As shown, in the manufacturing method of Example 4, the wrinkles of the optical laminate S are marked with "◎" on both the OS side and the DS side. Figure 12 In the manufacturing method of Embodiment 3, the end of the first optical film F1 on the side of relaxation (the end on the DS side) and the end of the second optical film F2 on the side of relaxation (the end on the OS side) are located on different sides. However, in the manufacturing method of Embodiment 4, the end of the first optical film F1 on the side of relaxation (the end on the OS side) and the end of the second optical film F2 on the side of relaxation (the end on the OS side) are located on the same side, and an optical laminate S with these ends stacked is manufactured. Therefore, it can be seen that in the manufacturing method of Embodiment 3, the wrinkles of the optical laminate S are "0", but in the manufacturing method of Embodiment 4, they are improved to "◎".

[0182] As explained above, the manufacturing methods of Examples 1 to 4 can suppress the generation of wrinkles and surface scratches in the optical laminate S that could not be suppressed in the manufacturing methods of Comparative Examples 1 to 3, and can also suppress the curling of the optical laminate S after being cut to product size that could not be suppressed in the manufacturing method of the Reference Example.

[0183] Explanation of reference numerals in the attached figures

[0184] 10··· Clamping Rollers

[0185] 20···First guide roller (guide roller)

[0186] 30···Second guide roller (guide roller)

[0187] 10L, 20L, 30L... Rotary Shaft

[0188] F1···First Optical Film

[0189] F2···Second optical film

[0190] S···Optical Stack

Claims

1. A method for manufacturing an optical laminate, which is a method for manufacturing an optical laminate by joining a first optical film of a long strip that has been stretched in a lateral direction and a second optical film of a long strip that has been stretched in a lateral direction while conveying them in a length direction with a nip roll, characterized in that, Includes the following steps: A guide roller, which guides the first optical film and / or the second optical film toward the clamping roller, is disposed upstream of the first optical film and / or the second optical film in the conveying direction, relative to the clamping roller. Adjust the orientation of the guide roller so that the rotation axis of the guide roller is inclined from a state parallel to the rotation axis of the clamping roller toward the end of the guide roller that is slack in the width direction of the first optical film and / or the second optical film.

2. The method for manufacturing an optical laminate according to claim 1, characterized in that, When both the first optical film and the second optical film have ends that have a loose side, the clamping roller is used to bond the first optical film and the second optical film together in such a way that the ends of the first optical film and the second optical film that have a loose side are stacked together.

3. The method for manufacturing an optical laminate according to claim 1 or 2, characterized in that, The first optical film is a protective film having a substrate layer and an adhesive layer. The second optical film is a diaphragm. The adhesive layer of the first optical film is bonded to the second optical film.

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