Optical film laminate having bulge, and method and apparatus for producing same

Abstract

The present invention provides an optical film laminate in which bulging at an end of a cut portion that has been cut by laser light is suppressed. The present invention provides an optical film laminate which has an arbitrary shape, and in which a first resin film is superposed on one surface of an optical functional layer that includes one or more films, and a second resin film is superposed on the other surface. The optical film laminate has a first bulge at an end of the first resin film. In addition, the optical film laminate has a second bulge at an end of the second resin film, which is at a position corresponding to the end of the first resin film. The height of the first bulge and the height of the second bulge are different from each other.

Description

Optical film laminate with raised portion, and manufacturing method and manufacturing device thereof

[0001] The present invention relates to an optical film laminate and a manufacturing technology thereof, and more specifically to an optical film laminate in which protrusions that may occur at the edges of cut portions are suppressed when the optical film laminate and a substrate film are cut with laser light while being held in electrostatic contact with each other before cutting, and a manufacturing method and apparatus for the same.

[0002] Optical display devices such as liquid crystal display devices and organic EL display devices use various optical film laminates such as polarizing films and retardation films. Conventional optical film laminates are manufactured through a number of different processes depending on the application and shape of the final product.

[0003] For example, in the manufacturing process of optical film laminates for smartphones, a long web-like laminate having a predetermined width in which multiple films are laminated is fed out and cut to a predetermined length using a circular blade, thereby obtaining multiple rectangular optical film laminates. Alternatively, in the manufacturing process of optical film laminates for in-vehicle applications and smartwatches, for which demand has been increasing in recent years, a long web-like laminate having a predetermined width is fed out and punched out using a Thomson die, thereby obtaining multiple optical film laminates of any desired shape. In either process, a sheet-like laminate may be used instead of the long web-like laminate, or a sheet-like mother laminate from which multiple optical film laminates can be obtained from a single sheet may be used. The multiple optical film laminates obtained in this manner are stacked, edge-treated as necessary, packaged, and shipped.

[0004] However, if various processes are adopted according to the use and shape of the final product, different manufacturing equipment must be introduced for each use and shape, and individual measures must be taken for each manufacturing equipment, which results in increased manufacturing costs. Therefore, it is desirable to realize a unified manufacturing process regardless of the use and shape of the final product. In order to realize a unified manufacturing process, it is preferable to adopt a method of cutting the laminate using laser light instead of a circular blade or Thomson die.

[0005] When a long web-like or sheet-like laminate is cut with a laser beam, protuberances (protuberances) may occur at the edges of the cut laminate, or fumes (fine dust particles formed by condensation of vapor generated during melting) may adhere to the edges. If protuberances occur at the edges, when multiple optical film laminates are stacked with their edges aligned, the protuberances of each optical film laminate may become misaligned with respect to each other, or problems may occur in image recognition. This may result in problems with packaging during shipping, problems during alignment for bonding to liquid crystal cells or organic EL cells in later processes, and problems when removing optical film laminates one by one from a stack of multiple stacked optical film laminates.

[0006] Furthermore, for example, when peeling a surface protective film from an optical film laminate having the surface protective film in a later step, the surface protective film can usually be peeled off by pulling up a release tape attached to its surface. However, if there is a protrusion at the end of the optical film laminate (in this case, the end of the surface protective film), the contact area between the end of the release tape and the surface of the surface protective film becomes smaller than when there is no protrusion, and there are cases where the surface protective film cannot be peeled off even when the release tape is pulled up.

[0007] Patent Document 1 proposes a method for removing fumes generated when cutting a multilayer optical film with laser light, but does not disclose the occurrence of protrusions at the edge of the cut laminate when cutting a multilayer optical film with laser light, or a means for solving this problem.

[0008] Special Publication No. 2005-526992

[0009] In view of the above problems, the present invention aims to provide an optical film laminate in which protrusions at the edges of cut portions cut with laser light are suppressed. Another object of the present invention is to provide a method and apparatus for manufacturing an optical film laminate in which protrusions at the edges are suppressed when cut with laser light.

[0010] The present inventors have found that by laminating a substrate film (carrier) on a laminate (raw material laminate) before it is cut with laser light, charging the two together using static electricity to bring them into close contact, and then cutting with laser light, it is possible to obtain an optical film laminate in which no protrusions are generated at the edge of the surface on which the substrate film is laminated, or if any are generated, the size of the protrusions is suppressed.

[0011] In one aspect, the present invention provides an optical film laminate of any shape, in which a first resin film is laminated on one side of an optical functional layer including one or more films, and a second resin film is laminated on the other side. The optical film laminate has a first raised portion at an end of the first resin film. The optical film laminate also has a second raised portion at an end of the second resin film at a position corresponding to the end of the first resin film. The height of the first raised portion and the height of the second raised portion are different.

[0012] In another aspect, the present invention provides a method for producing an optical film laminate of any shape, in which a first resin film is laminated on one side of an optical functional layer containing one or more films and a second resin film is laminated on the other side. In this method, first, a raw material laminate is transported, in which a first resin film is laminated on one side of an optical functional layer containing one or more films and a second resin film is laminated on the other side. Next, a substrate is laminated on either the first resin film or the second resin film of the raw material laminate to obtain a raw material laminate with a substrate. Next, static electricity is applied to the raw material laminate, the substrate, or the raw material laminate with a substrate, or a combination thereof, to bring the substrate and the raw material laminate into close contact with each other, and then a cut surface of any shape is formed on the raw material laminate with a substrate using laser light. Static electricity is removed from the raw material laminate with a substrate, and one or more optical film laminates having cut surfaces of any shape are peeled off from the substrate.

[0013] In yet another aspect, the present invention provides an apparatus for producing an optical film laminate of any shape, in which a first resin film is laminated on one side of an optical functional layer containing one or more films and a second resin film is laminated on the other side, the apparatus comprising: a conveying device for conveying a raw material laminate in which the first resin film is laminated on one side of an optical functional layer containing one or more films and the second resin film is laminated on the other side, a lamination device for laminating a substrate on either the first resin film or the second resin film of the raw material laminate to produce a raw material laminate with substrate, a charging device for charging the raw material laminate, the substrate, or the raw material laminate with substrate, or a plurality of these, with static electricity to bond the substrate and the raw material laminate, a laser cutting device for cutting the raw material laminate with substrate to form one or more optical film laminates of any shape, a static elimination device for removing static electricity from the raw material laminate with substrate, and a peeling device for peeling the one or more optical film laminates of any shape from the substrate.

[0014] 1 shows schematic cross-sectional views of an optical film laminate having raised portions according to one embodiment of the present invention, where (a) is an optical film laminate having raised portions on one side and not on the other side, and (b) is an optical film laminate having raised portions on both sides. Also, (c) is a schematic cross-sectional view showing a state in which a raw material laminate has been cut by laser light. FIG. 1 is a conceptual diagram of a process for manufacturing an optical film laminate having raised portions. FIG. 1 is a conceptual diagram of an apparatus for manufacturing an optical film laminate having raised portions according to a first embodiment, showing an apparatus for laminating a sheet-like base film on a sheet-like raw material laminate and performing cutting. FIG. 2 is a conceptual diagram of an apparatus for manufacturing an optical film laminate having raised portions according to a second embodiment, showing an apparatus for laminating a web-like base film on a sheet-like raw material laminate and performing cutting. FIG. 3 is a conceptual diagram of an apparatus for manufacturing an optical film laminate having raised portions according to a third embodiment, showing an apparatus for laminating a web-like base film on a web-like raw material laminate and performing cutting.

[0015] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0016] (Configuration of Optical Film Laminate Having Protuberances) FIG. 1 shows a schematic cross-sectional view of an optical film laminate having protuberances according to one embodiment of the present invention. FIG. 1( a) is a schematic cross-sectional view of an optical film laminate F1 having protuberances on one surface 11 and no protuberances on the other surface 13. FIG. 1( c) is a schematic cross-sectional view showing a raw material laminate RM cut with laser light. The optical film laminate F1 can be produced by a manufacturing method according to the present invention, which will be described later. For example, the optical film laminate F1 can be obtained by laminating a substrate film BF on one surface (the lower surface of the laminate in FIG. 1( c)) of a web-like raw material laminate RM, charging it with static electricity to bring the raw material laminate RM and the substrate film BF into close contact, and then cutting it with laser light. FIG. 1( a) shows the cut portion as viewed from the side (as viewed from diagonally below and to the left in FIG. 1( c)). The parts designated by reference numbers in FIG. 1( c) correspond to the parts designated by reference numbers in FIGS. 1( a) and 1( b).

[0017] The optical film laminate F1 is a laminate in which a surface protective film PF is laminated on one side of a polarizing film POL and a release liner RL is laminated on the other side. Although this configuration of optical film laminate is described as an example in this specification, the optical film laminate to which the present invention can be applied is not limited to this. For example, the optical film laminate may have an optical functional layer composed of multiple films instead of a polarizing film. Furthermore, the optical film laminate may be a laminate in which a release liner RL is laminated on one side of the optical functional layer and surface protective films PF are laminated on multiple sides. The optical functional layer may be, for example, a polarizing film, a retardation film, a combination of a polarizing film and a retardation film, an OCA (Optical Clear Adhesive), a combination of a polarizing film and an OCA, a PET film, or the like. Alternatively, the optical film laminate can be, for example, a laminate in which a light release liner is laminated on one side of an OCA and a heavy release liner is laminated on the other side, or a laminate in which a light release liner is laminated on one side of a PET film and a heavy release liner is laminated on the other side.

[0018] The optical film laminate F1 can be cut into a laminate having any shape from, for example, a web-like raw material laminate RM using laser light. Arbitrary shapes include not only rectangular, circular, elliptical, and other shapes, but also irregular shapes. Irregularly shaped laminates can include laminates with special shapes, such as a rectangular shape having a notch or recess (a so-called notch) on one side, a semi-cylindrical shape used in automotive instrument panels, or a rectangular film with a circular or rectangular hole in part. For example, in the case of a rectangular laminate having a notch or recess (a so-called notch) on one side, the cut surface formed by the laser light will be formed not only on each side but also inside the notch or recess.

[0019] The optical film laminate F1 has a raised portion 12 at the edge 11a of the surface 11 facing the surface protective film PF, but does not have a raised portion at the edge 13a of the surface 13 facing the release liner RL. In FIG. 1( a), the optical film laminate F1 has the raised portion 12 only on the surface 11 facing the surface protective film PF, but this is not limited thereto, and the optical film laminate F1 may have a raised portion only on the surface 13 facing the release liner RL. Here, the edge 11a includes the edge 11b ( FIG. 1( c)) of the cut portion of the surface 11 of the optical film laminate F1 and the area inwardly adjacent thereto. The same applies to the edge 13a.

[0020] The optical film laminate F1 is obtained by cutting a raw material laminate RM. The raw material laminate RM can be a laminate in which the same resin films as those in the optical film laminate F1 are laminated. The raised portion 12 is formed, for example, when the resin film (surface protection film) laminated on the outermost surface of the portion cut by the laser light is melted by the heat generated when cutting the web-like raw material laminate RM using laser light, causing the resin film to rise and solidify. In addition, fine dust (fumes) is generated by condensation of vapor from the raw material laminate RM produced during melting, and this dust may scatter around the cut surface.

[0021] In the method for manufacturing an optical film laminate according to the present invention, as described below, before cutting the raw laminate RM with laser light, a base film BF is laminated on the surface 13 on the release liner RL side, and the substrate-attached raw laminate RMB is charged with static electricity. Because the static electricity causes the surface 13 of the release liner RL of the raw laminate RM to adhere to the base film BF, when the raw laminate RM is cut in this state, no protrusions are typically formed on the surface 13. Furthermore, no fumes are generated on the surface 13. Here, "adhesion" refers to a state in which no air layer or air pocket exists between the two films, and no air layer or air pocket is formed even during transport. If the surface 13 of the release liner RL and the base film BF are completely in close contact with each other, there is no physical space for protrusions to form. Furthermore, heat generated during cutting with laser light is unlikely to be conducted to the base film BF, causing a rise in the surface temperature, and therefore no protrusions are formed on the surface 13.

[0022] The raised portions 12 have a predetermined height. The height is the distance from the surface 11 to the top of the raised portions 12. The height of the raised portions 12 is preferably less than 12% of the thickness of the optical film laminate F1 at the portion where the raised portions 12 are not present, more preferably less than 8%, and even more preferably less than 5%. The height of the raised portions 12 is preferably less than 20 μm, more preferably less than 14 μm, and even more preferably less than 8 μm. If the height of the raised portions 12 is less than 12% of the thickness of the optical film laminate F1, when multiple optical film laminates F1 are stacked with their edges aligned, the raised portions 12 do not cause misalignment of the optical film laminates F1, and image recognition problems do not occur. Furthermore, if the height of the raised portions 12 is less than 12% of the thickness of the optical film laminate F1, it does not affect the peeling of the surface protective film PF using the release tape. The raised portions 12 tend to become taller as the intensity of the laser light used for cutting increases.

[0023] The width of the raised portion 12, i.e., the length from the edge 11b of the optical film laminate F1 toward the inside (the left-right direction in FIG. 1( a)), is preferably less than 100 μm, and more preferably less than 80 μm. If the width of the raised portion 12 is 100 μm or more, the raised portion may be recognized and the line width of the captured image may become thicker during alignment and lengthening for bonding the optical film laminate F1 to a liquid crystal cell or the like in a later process, and depending on the set threshold value, this may cause a displacement of the reading position, resulting in problems such as reduced bonding accuracy and reading errors.

[0024] The optical film laminate F1 has an end surface 15, which is a cut surface cut by laser light. The end surface 15 is located between an edge 11b of the surface 11 and an edge 13b of the surface 13 of the optical film laminate F1. Due to the characteristics of forming a cut surface by laser light, the end surface 15 is typically an inclined surface, but is not limited to this and may be a surface perpendicular to the surfaces 11 and 13. Although the end surface 15 is depicted as a flat surface in FIG. 1( a), it is not limited thereto and may be a curved surface or a combination of a flat surface and a curved surface when the optical film laminate F1 is to have an arbitrary shape depending on the application.

[0025] Fig. 1(b) is a schematic cross-sectional view of an optical film laminate F2 having protrusions on both one surface 21 and the other surface 23. Like F1, optical film laminate F2 is produced by the production method according to the present invention, which will be described later. Fig. 1(b) shows the cut portion as viewed from the side (diagonally downward left of Fig. 1(c)).

[0026] The optical film laminate F2 is a laminate in which a surface protective film PF is laminated on one side of a polarizing film POL and a release liner RL is laminated on the other side. The optical film laminate F2 has a raised portion 22 at the edge 21a of the surface 21 facing the surface protective film PF and a raised portion 24 at the edge 23a of the surface 23 facing the release liner RL. The raised portion 22 is formed, for example, when the resin film (surface protective film, release liner) laminated on the outermost surface of the portion cut by the laser beam melts due to heat generated when cutting a web-like raw material laminate RM with laser beam, causing the resin film to rise to the surface and solidify. Furthermore, fine dust (fumes) formed by condensation of vapor from the raw material laminate RM produced during melting may also be generated and scattered around the cut surface.

[0027] When producing the optical film laminate F2, as in the case of producing the optical film laminate F1, a base film BF is laminated on the surface 23 of the release liner RL before cutting the raw laminate RM with laser light, and static electricity is charged. As described in the explanation of the optical film laminate F1, if the surface 23 of the release liner RL and the base film BF are firmly adhered to each other, no raised portion will be formed. However, there may be cases where the degree of adhesion is partially insufficient due to, for example, reduced and / or uneven charging, and if a small air layer is formed in this area due to impact during cutting with the laser light or uneven tension in transporting the substrate-attached raw laminate RMB, a raised portion may be formed. This is the reason why the raised portion 24 is formed on the surface 23 of the optical film laminate F2 that is adjacent to the release liner RL, even though the base film BF is laminated thereon.

[0028] In the optical film laminate F2, the end 23a where the raised portion 24 is located is located at a position corresponding to the end 21a where the raised portion 22 is located. Specifically, the end 21a is located adjacent to the cut portion caused by the laser light on the surface 21 of the surface protective film PF in the optical film laminate F2, and the end 23a is located adjacent to the cut portion caused by the laser light on the surface 23 of the release liner RL.

[0029] In the optical film laminate F2, the raised portions 24 have a lower height than the raised portions 22. Preferably, the sum of the height of the raised portions 22 (the distance from the surface 21 to the top of the raised portions 22) and the height of the raised portions 24 (the distance from the surface 23 to the top of the raised portions 24) is less than 20%, more preferably less than 15%, and even more preferably less than 10% of the thickness of the optical film laminate F2 in the portion where the raised portions 22 and 24 are not present. The sum of the height of the raised portions 22 and 24 is preferably 35 μm or less, more preferably less than 30 μm, and even more preferably 15 μm or less. The height of the raised portions 24 is preferably 1 μm or less. It is most preferable that the height of the raised portions 24 is zero, in which case the optical film laminate F2 corresponds to the optical film laminate F1.

[0030] Like the optical film laminate F1, the optical film laminate F2 has an end face 25, which is a cut surface formed by laser light, between the edge 21b of the surface 21 and the edge 23b of the surface 23. Like the end face 15, the end face 25 is also typically an inclined surface, but is not limited to this and may be a surface perpendicular to the surfaces 21 and 23. Furthermore, although the end face 25 is shown as a flat surface in Fig. 1(b), it is not limited to this and the end face 25 may be a curved surface or a combination of a flat surface and a curved surface.

[0031] (Process for manufacturing an optical film laminate according to the present invention) FIG. 2 is a conceptual diagram of a process for manufacturing an optical film laminate F1 or F2 having raised portions. In FIG. 2( a), a substrate film BF is laminated on one surface of a raw material laminate RM to obtain a substrate-attached raw material laminate RMB. The raw material laminate RM is a laminate in which a surface protective film PF is laminated on one surface of a polarizing film POL and a release liner RL is laminated on the other surface, and may be in the form of a web or a sheet. Here, the substrate film BF is laminated on the surface 13R of the raw material laminate RM facing the release liner RL, but this is not limited thereto and the substrate film BF may also be laminated on the surface 11R facing the surface protective film PF.

[0032] The base film BF may be a non-adhesive material without an adhesive layer, or may be an adhesive material. In the manufacturing method according to the present invention, the raw material laminate RM and the base film BF are adhered together by static electricity, so a non-adhesive material can be used for the base film BF. Therefore, for example, it is possible to reuse the base film BF used in the process of manufacturing the optical film laminate according to the present invention, or to use waste material used in other processes or products, which can be expected to reduce the amount of base film used and reduce manufacturing costs. The non-adhesive base film BF that can be used in the present invention may be any film that does not stretch easily even when tension is applied, and examples of the base film BF that can be used include polyethylene terephthalate (PET) film and polyethylene film.

[0033] On the other hand, if an adhesive material is used as the base film BF, the raw laminate RM and the base film BF can be more firmly adhered to each other, making it possible to more effectively prevent the occurrence of protrusions on the surface where the base film BF is laminated. However, if an adhesive material is used, it is difficult to reuse a used base film BF, which increases the amount of material used and may therefore increase manufacturing costs. Furthermore, if the adhesive strength of the material used is greater than the adhesive strength between the individual films of the raw laminate RM, the base film BF may not be peeled off or the films of the raw laminate RM may peel off, which limits the base film BF that can be used. Therefore, it is preferable that the adhesive base film BF be a weakly adhesive material, and for example, a surface protection material AW303EB manufactured by Nitto Denko Corporation may be used.

[0034] Next, as shown in FIG. 2( b), a substrate-attached raw laminate RMB, which is a laminate of the raw laminate RM and the base film BF, is electrostatically charged (40). Charging with static electricity allows the opposing surfaces of the raw laminate RM and the base film BF to adhere to each other (FIG. 2( c)). As shown in FIGS. 2( b) and 2( c), even if there is a portion V where the raw laminate RM is separated from the surface of the base film BF, the separated portion V can be eliminated by electrostatically charging the raw laminate RM and the base film BF to adhere to each other. Charging with static electricity is not limited to being performed on the substrate-attached raw laminate RMB; it may also be performed on the raw laminate RM before it is laminated with the base film BF, or on the base film BF before it is laminated to the raw laminate RM. Although not shown, when charging the substrate-attached raw material laminate RMB with static electricity, it is preferable to place the portion of the substrate-attached raw material laminate RMB to be charged in contact with a conductor such as a metal roller, and to place a charging device on the opposite side of the metal roller so as to face the contacting portion.

[0035] It is preferable that the raw material laminate RM and the base film BF are uniformly charged with static electricity over their entire surfaces. The amount of static electricity to be charged is such that the base film BF and the raw material laminate RM do not peel (do not lose adhesion) during transport and when the cut surface is formed by the laser beam 41. The amount of static electricity is preferably −10 kV or more and −0.5 kV or less, or 0.5 kV or more and 10 kV or less, more preferably −4.0 kV or more and −0.5 kV or less, or 0.5 kV or more and 4.0 kV or less, and most preferably −4.0 kV or more and −0.5 kV or less. If the amount of static electricity is less than −10 kV or more than +10 kV, the effect of suppressing the occurrence of protrusions is increased, but problems such as attraction of foreign matter, incomplete removal of static electricity and poor peeling, and adverse effects on peripheral devices due to atmospheric discharge occur.If the amount of static electricity is more than −0.5 kV and less than +0.5 kV, the adhesion is weak, and there is a problem that voids are generated by the impact when irradiated with laser light.

[0036] 2(c), after electrostatic charging, the substrate-attached raw material laminate RMB is cut using laser light 41 to form an optical film laminate F1. Cutting with laser light 41 is performed by irradiating the substrate-attached raw material laminate RMB from the side opposite the base film BF (here, the side of the surface protective film (PF)). The intensity of the laser light 41 is preferably set so that it reaches a depth that cuts the surface protective film PF, polarizing film POL, and release liner RL but does not cut the base film BF.

[0037] As described above, cutting with the laser beam 41 is performed linearly when the required shape of the optical film laminate F1 is rectangular, but may be performed curvedly when the shape of the optical film laminate F1 is arbitrary. On both sides of the cut portion with the laser beam 41, the raw material laminate RM melts due to the heat generated during cutting, and rises and solidifies on the surface, forming raised portions 12, as shown in Fig. 2(d). The raised portions 12 are formed on part or all of the end portion 11a of the surface protective film PF.

[0038] Next, as shown in Fig. 2(d), after cutting with laser light 41, static electricity is removed from the substrate-attached raw material laminate RMB (42). By removing static electricity, the raw material laminate RM and the substrate film BF are released from their tightly adhered state. If there were any separated areas V before charging, these areas may separate again. When removing static electricity, it is preferable to remove static electricity from the substrate-attached raw material laminate RMB while it is not in contact with anything, as opposed to when charging.

[0039] Finally, as shown in FIG. 2( e), the portion of the raw laminate RM corresponding to the optical film laminate F1 is peeled from the base film BF, thereby obtaining an optical film laminate F1 having the raised portion 12. When a non-adhesive material is used for the base film BF, the release liner RL and the base film BF can be easily peeled off by removing static electricity. On the other hand, when an adhesive material is used for the base film BF, depending on the adhesive strength, even after removing static electricity, the release liner RL and the base film BF may not be properly peeled off when attempting to peel the optical film laminate F1 from the base film BF. Instead, peeling may occur between the release liner RL and the polarizing film POL, with the release liner RL remaining on the base film BF. Therefore, when an adhesive base film BF is used, it is preferable that the adhesive strength of the base film BF be smaller than that of the release liner RL.

[0040] (Apparatus for manufacturing an optical film laminate having raised portions) [First embodiment] Fig. 3 is a conceptual diagram of an apparatus 50 for manufacturing an optical film laminate having raised portions according to Embodiment 1. The apparatus 50 is a sheet-to-sheet type apparatus that laminates a sheet-like base film BF on a sheet-like raw material laminate RM to form a sheet-like raw material laminate RMB with base, and then charges the raw material laminate RMB with base and cuts it with laser light.

[0041] The device 50 includes a conveying device 51a that takes out a sheet-shaped raw material laminate RM from a stocker, for example, and conveys it to a lamination device 52 with a base film BF, and a conveying device 51b that similarly takes out a sheet-shaped base film BF from the stocker and conveys it to the lamination device 52 with a raw material laminate RM. As the conveying devices 51a and 51b, a suction pickup device, a conveying roller, or the like that is well known to those skilled in the art can be used as appropriate.

[0042] The apparatus 50 includes a laminating device 52 and a charging device 53. In the laminating device 52, the raw material laminate RM and the base film BF are passed between a pair of laminating rollers 52a to form a sheet-like raw material laminate RMB with base material. As the laminating roller 52a, a laminating roller well known to those skilled in the art for laminating two resin films with an adhesive can be appropriately used.

[0043] The charging device 53 is a device for charging the raw material laminate RM with static electricity. Any charging device known to those skilled in the art can be used as the charging device 53, such as the JPK-3 manufactured by Kasuga Electric Co., Ltd. In FIG. 3 , the charging device 53 is located downstream of the laminating device 52 and above the raw material laminate RM. Therefore, in the device 50, static electricity is applied from the raw material laminate RM side of the substrate-attached raw material laminate RMB, which is a laminate of the raw material laminate RM and the base film BF, thereby causing the raw material laminate RM and the base film BF to adhere to each other through static electricity. To ensure the most desirable adhesion through charging, it is preferable to charge the substrate-attached raw material laminate RMB. However, the location of the charging device 53 is not limited thereto; the charging device 53 may be located downstream of the laminating device 52 on the side of the base film BF. Alternatively, the charging device 53 may be located upstream of the laminating device 52 near the base film BF. In this case, the base film BF is charged with static electricity before being laminated on the raw material laminate RM, so that the two come into close contact when laminated in the lamination device 52. Alternatively, the charging device 53 may be located upstream of the lamination device 52, near the raw material laminate RM. In this case, the raw material laminate RM is charged with static electricity before being laminated, so that the two come into close contact when laminated in the lamination device 52. Alternatively, the charging device 53 may be located in more than one of the above locations. For example, charging devices may be located upstream and downstream of the lamination device 52, so that both the raw material laminate RM and the substrate-attached raw material laminate RMB are charged.

[0044] The charged raw material laminate RMB with substrate is transported onto a pedestal 55 for laser cutting by a transport device 54 including an adsorption pickup device well known to those skilled in the art. The pedestal 55 is preferably an adsorption pedestal so that the raw material laminate RMB with substrate placed thereon does not move during laser cutting. Any pedestal well known to those skilled in the art can be used as the pedestal 55.

[0045] The apparatus 50 includes a laser cutting device 56. The laser cutting device 56 may include, for example, a laser light generating unit that generates laser light and irradiates the substrate-attached raw material laminate RMB placed on the pedestal 55, and a moving unit that moves the laser light generating unit so as to cut the substrate-attached raw material laminate RMB into a desired shape. The laser cutting device 56 may be any device known to those skilled in the art that is used to cut resin films.

[0046] As described above, the intensity of the laser light is preferably set so as to reach a depth that cuts the surface protective film PF, polarizing film POL, and release liner RL contained in the substrate-attached raw laminate RMB but does not cut the base film BF. The laser cutting device 56 can cut the raw laminate RM contained in the substrate-attached raw laminate RMB to form an optical film laminate F1 of any shape on the base film BF. In this case, only one optical film laminate F1 can be formed from one substrate-attached raw laminate RMB, or multiple optical film laminates F1 can be formed from one substrate-attached raw laminate RMB.

[0047] The device 50 includes a static eliminator 57. The static eliminator 57 is a device for removing static electricity from the charged raw material laminate RMB with substrate. As the static eliminator 57, any static eliminator known to those skilled in the art can be used as appropriate. For example, the static eliminator 57 may be a JPK-3 manufactured by Kasuga Electric Co., Ltd.

[0048] In the substrate-attached raw material laminate RMB including the optical film laminate F1 from which static electricity has been removed by the static eliminator 57, the tight contact state between the substrate-attached raw material laminate RMB and the optical film laminate F1 and the base film BF is released, and the optical film laminate F1 is in a state where it can be easily peeled off from the base film BF. In the first embodiment, the optical film laminate F1 can be obtained by peeling off the sheet-like base film BF after static elimination.

[0049] To this end, the apparatus 50 includes a peeling device 58 that bonds the tape TP to the base film BF to connect the sheet-like base film BF and peels the base film BF together with the tape TP from the optical film laminate F1. The tape TP is unwound from the tape roll TPR with its adhesive side facing the base film BF. The unwound tape TP is bonded in the bonding section 58a to the base film BF of the substrate-attached raw material laminate RMB including the optical film laminate F1, which has been fed from the base 55 and from which static electricity has been removed. The position where the tape TP is bonded is not limited, but may be at least a portion of the base film BF, for example, only both ends. In FIG. 3, two narrow strips of tape TP are shown being unwound from the roll TPR.

[0050] Downstream of the bonding section 58a between the substrate-attached raw laminate RMB and the tape TP, the base film BF bonded with the tape TP is pulled away from the conveying direction of the substrate-attached raw laminate RMB via a peeling roller (or peeling bar) 58b. Thus, while the base film BF connected with the tape TP is wound up, the optical film laminate F1 peeled from the base film BF is sent out of the peeling device 58 without changing the conveying direction by the peeling roller 58b and removed by a conveying device 59 well known to those skilled in the art. In this manner, optical film laminates F1 having one or more arbitrary shapes can be obtained. The optical film laminate F1 is then delivered to subsequent processes, such as an edge processing process or a packaging process, by a conveying device (not shown) including a pickup device well known to those skilled in the art.

[0051] Second Embodiment Fig. 4 is a conceptual diagram of an apparatus 60 for manufacturing an optical film laminate having raised portions according to a second embodiment. The apparatus 60 is a sheet-web type apparatus that laminates a web-like substrate film BF on a sheet-like raw material laminate RM to form a web-like substrate-attached raw material laminate RMB, and then charges the substrate-attached raw material laminate RMB and cuts it with laser light. The following mainly describes the configuration that differs from the apparatus 50 of embodiment 1.

[0052] The apparatus 50 is configured so that a sheet-like raw material laminate RM is laminated on a sheet-like base film BF to form a sheet-like base-attached raw material laminate RMB. In contrast, the apparatus 60 is configured so that a plurality of sheet-like raw material laminates RM are continuously laminated on a web-like base film BF in the length direction to form a web-like base material laminate RMB. For this reason, the apparatus 60 is configured so that the web-like base film BF unwound from the base film roll BFR is transported to a lamination device 62 that laminates the raw material laminate RM and the base film BF. The transport device 61 for the sheet-like raw material laminate RM and its functions can be similar to the transport device 51a of the apparatus 50.

[0053] In the laminating device 62, the sheet-like raw material laminate RM and the web-like base film BF are passed between a pair of laminating rollers 62a, thereby forming the web-like raw material laminate RMB with base material.

[0054] The device 60 includes a charging device 63 downstream of the laminating device 62. The charging device 63 charges the substrate-attached raw material laminate RMB with static electricity after the sheet-like raw material laminate RM is laminated on the web-like base film BF, thereby bringing the raw material laminate RM and the base film BF into close contact with each other by static electricity. The location of the charging device 63 is not limited thereto, and the charging device 63 may be disposed upstream of the laminating device 62 so as to charge the sheet-like raw material laminate RM or the web-like base film BF before they are laminated.

[0055] The charged web-like substrate-attached raw material laminate RMB is conveyed over a pedestal 65 by a conveying device 64 known to those skilled in the art. The substrate-attached raw material laminate RMB stops on the pedestal 65 and is then cut by laser light from a laser cutting device 66. The pedestal 65 is preferably an adsorption pedestal so that the substrate-attached raw material laminate RMB placed thereon does not move during laser cutting. After cutting, the substrate-attached raw material laminate RMB is neutralized by a neutralization device 67. The laser cutting device 66 and its function can be similar to the laser cutting device 56 of the device 50, and the neutralization device 67 and its function can be similar to the neutralization device 57 of the device 50.

[0056] In the substrate-attached raw material laminate RMB including the optical film laminate F1 from which static electricity has been removed by the static eliminator 67, the close contact between the raw material laminate RM and the optical film laminate F1 and the web-like base film BF is released, and the optical film laminate F1 can be easily peeled off from the base film BF. The apparatus 60 includes a peeling device 68 downstream of the static eliminator 67 to peel off the optical film laminate F1 from the sheet-like base film BF.

[0057] The peeling device 68 has a peeling roller (or peeling bar) 68a, and the web-like base film BF is pulled away from the conveying direction of the substrate-attached raw laminate RMB via the peeling roller 68a. Therefore, the web-like base film BF is peeled off from the optical film laminate F1 and taken up. The remaining portion RMR of the raw laminate from which the optical film laminate F1 has been cut is released from its intimate contact with the base film BF by being neutralized, and therefore separates from the base film BF when the web-like base film BF is taken up, and is, for example, dropped and collected. Meanwhile, the optical film laminate F1 peeled off from the base film BF is sent out of the peeling device 68 without changing the conveying direction by the peeling roller 68a and is removed by a conveying device 69 known to those skilled in the art. In this manner, optical film laminates F1 having one or more arbitrary shapes can be obtained.

[0058] 5 is a conceptual diagram of an apparatus 70 for manufacturing an optical film laminate having raised portions according to a third embodiment. The apparatus 70 is a web-to-web type apparatus that laminates a web-like base film BF on a web-like raw material laminate RM to form a web-like base-attached raw material laminate RMB, and then charges the base-attached raw material laminate RMB and cuts it with laser light. Below, the configuration that differs from the apparatus 50 of embodiment 1 and the apparatus 60 of embodiment 2 will mainly be described.

[0059] The apparatus 50 is configured so that a sheet-like raw material laminate RM is laminated on a sheet-like base film BF to form a sheet-like base-attached raw material laminate RMB, while the apparatus 60 is configured so that a plurality of sheet-like raw material laminates RM are continuously laminated on a web-like base film BF to form a web-like base-attached raw material laminate RMB. In contrast, the apparatus 70 is configured so that a web-like raw material laminate RM is laminated on a web-like base film BF to form a web-like base-attached raw material laminate RMB. For this reason, the apparatus 70 is configured so that the web-like raw material laminate RM unwound from the raw material laminate roll RMR is transported to a lamination device 72 that laminates the raw material laminate RM and the base film BF together.

[0060] In the laminating device 72, the web-like raw material laminate RM and the web-like base film BF are passed between a pair of laminating rolls 72a, thereby forming a web-like raw material laminate RMB with base material.

[0061] The device 70 includes a charging device 73 downstream of the laminating device 72. The charging device 73 charges the substrate-attached raw material laminate RMB after the web-like raw material laminate RM is laminated on the web-like base film BF, thereby bringing the raw material laminate RM and the base film MB into close contact with each other by static electricity. The location of the charging device 73 is not limited thereto, and the charging device 73 may be disposed upstream of the laminating device 72 so as to charge the web-like raw material laminate RM or the web-like base film BF before they are laminated.

[0062] The charged raw material laminate RMB with substrate is transported by a transport device 74 and cut by laser light on a base 75. The cut raw material laminate RMB with substrate is then neutralized by a static eliminator 77. The transport device 74, the base 75, the laser cutting device 76, and the static eliminator 77, as well as their functions, may be similar to those of the device 60.

[0063] In the substrate-attached raw material laminate RMB including the optical film laminate F1 from which static electricity has been removed by the static eliminator 77, the tight contact state between the substrate-attached raw material laminate RMB and the optical film laminate F1 and the web-like base film BF is released, and the optical film laminate F1 can be easily peeled off from the base film BF. The apparatus 70 also includes a peeling device 78 downstream of the static eliminator 77 to peel the optical film laminate F1 from the web-like base film BF.

[0064] The peeling device 78 has a peeling roller (or peeling bar) 78a, and the web-like base film BF is pulled via the peeling roller 78a in a direction away from the conveyance direction of the substrate-attached raw laminate RMB. Therefore, the web-like base film BF is peeled from the optical film laminate F1 and taken up by a take-up roller. The remaining portion RMR of the web-like raw laminate from which the optical film laminate F1 has been cut is released from its intimate contact with the base film BF by being neutralized, and is taken up via the peeling roller 78a in a direction different from the direction in which the web-like base film BF is taken up. Meanwhile, the optical film laminate F1 that has been peeled from the base film BF by being neutralized and cut from the web-like raw laminate RM is sent out of the peeling device 78 without changing the conveyance direction by the peeling roller 78a and is removed by a conveying device 79 known to those skilled in the art. In this manner, optical film laminates F1 having one or more arbitrary shapes can be obtained.

[0065] Examples and comparative examples of the present invention are described below. Table 1 shows examples and comparative examples of the present invention. In the examples, an optical laminate was prepared in which a surface protection film was laminated on one side of a sheet-like optical functional film (optical functional layer) and a release liner was laminated on the other side, and a sheet-like carrier film was laminated on the surface of the release liner. This was nipped with a laminating roller well known to those skilled in the art to form a raw material laminate with a substrate, and static electricity was charged. In Examples 1 to 2 and Examples 4 to 6, charging was performed before nipping, and in Example 3, charging was performed after nipping. In Examples 1 to 5, a negative charge was applied, and in Example 6, a positive charge was applied.

[0066] Next, the amount of static electricity on the surface of the charged substrate-attached raw laminate was measured, and the substrate-attached raw laminate was cut with a laser beam from the side opposite to the side where the carrier film was laminated (the surface protective film side), leaving the carrier film behind. After cutting, the static electricity was removed, and the height of the protrusions formed at the end of the cut portion was measured for the optical film laminate obtained by peeling off the carrier film.

[0067] On the other hand, in the comparative example, the raw material laminate was nipped with a laminating roller known to those skilled in the art, and then cut with laser light without being charged, and the height of the raised portion of the optical film laminate after removing the carrier film was measured.

[0068] The optical laminate used was a mobile retarder polarizing film (GRT1794XH1UHC) manufactured by Nitto Denko Corporation, with a thickness of 178 μm. A 25 μm thick PET film was used as the carrier film. The static charging and de-staticizing device used in Examples 1 to 4 and 6 was a JPK-3 manufactured by Kasuga Electric Co., Ltd., while the device used in Example 5 was a PSM-2005PN manufactured by Kasuga Electric Co., Ltd. The laser light used for cutting was a CO laser with a wavelength of 9.4 μm. ２ A TLSM301 manufactured by Takei Electric Co., Ltd. was used as a laser light generator, and the laser was focused on the surface of the polarizing film and cut at an output of 35 W, a frequency of 15 kHz, and a feed rate of 500 mm / sec.

[0069] The height of the raised portion was measured as follows. For each of Examples 1 to 6 and Comparative Example, three optical film laminates were produced by the above method, and a laser microscope (manufactured by Keyence Corporation) was used to obtain a cross-sectional profile from an image of a portion of the edge of each cut portion of the optical film laminate. The amount of protrusion was measured at 50 locations from each cross-sectional profile, and the average value of the 50 protrusion amounts was calculated. For each of Examples and Comparative Example, the average values ​​of the protrusion amounts of the three optical film laminates calculated in this manner were further averaged, and this was defined as the height of the raised portion of the optical film laminate.

[0070]

[0071] In both Example 1 and Example 2, the amount of static electricity charged was -1.0 kV to -4.0 kV. However, in Example 1, charging was performed from the side opposite the carrier film of the substrate-attached raw material laminate, while in Example 2, charging was performed from the carrier film side of the substrate-attached raw material laminate. In both Examples, on the contact surface where the carrier film was laminated (the "release liner side" in Table 1), no raised portions were generated (Example 1), or if raised portions were generated, the height of the raised portions was 1 μm (Example 2). On the other hand, on the open surface where no carrier film was laminated (the "surface protection film side" in Table 1), raised portions with a height of 8 μm (Example 2) or 13 μm (Example 1) were generated.

[0072] In Example 3, the substrate-attached raw material laminate was charged before nipping. The charged surface was the surface opposite the carrier film. The static electricity value in Example 3 was larger than in Examples 1 and 2 (i.e., the static adhesion was weaker), ranging from -0.2 kV to -0.5 kV. The output of the charging device in Example 3 was the same as in Examples 1 and 2, but the static electricity value at the time of measurement was thought to be higher due to the charge being lost when the laminate was nipped after charging. In this example, raised portions occurred on both the contact surface and the open surface, but the raised portions on the contact surface were lower than the raised portions on the open surface.

[0073] In Example 4, the sample was charged from the side opposite the carrier film after nipping. The amount of static electricity measured was comparable to that in Example 3. In this example, the same charging device as in Examples 1 and 2 was operated at the same output to charge the sample, but the distance to the charging surface was increased compared to those examples, thereby adjusting the amount of static electricity to be comparable to that in Example 3. In this example, as in Example 3, raised portions occurred on both the contact surface and the open surface, but the raised portions on the contact surface were lower than the raised portions on the open surface.

[0074] In Examples 3 and 4, the amount of static electricity was greater than in Examples 1 and 2 (i.e., the adhesion force due to static electricity was weaker), which resulted in partial insufficient adhesion between the raw material laminate and the carrier film, and the impact of cutting with the laser light formed an air layer, resulting in higher protrusions on the adhesion surface compared to Examples 1 and 2.

[0075] In Example 5, the amount of static electricity was −11.0 kV to −12.0 kV, and charging occurred after nipping. When charging with such a small amount of static electricity (i.e., when the adhesion force due to static electricity is strong), no protrusions were generated on the contact surface, but problems such as attraction of foreign matter, poor peeling due to incomplete removal of static electricity, and adverse effects on peripheral devices due to atmospheric discharge may occur.

[0076] Example 6 shows the results when the base-attached raw material laminate was positively charged, which is the opposite of Examples 1 to 5. The amount of static electricity charged was +5 kV to +7 kV. When positively charged, the absolute value of the amount of static electricity charged was greater than in Examples 1 to 4, but the adhesion between the raw material laminate and the carrier film was weak, and the effect of suppressing the protrusions was similar to that of Example 4.

[0077] As described above, the comparative example shows the results when the substrate-attached raw material laminate was cut with laser light without being charged. The substrate-attached raw material laminate of the comparative example also became slightly charged due to friction, etc. In the comparative example, large protrusions were generated on both the contact surface and the open surface, regardless of whether a carrier film was used or not.

[0078] F1 Optical film laminate having raised portions on one surface 11 One surface 11a Edge 11b Edge 12 First raised portion 13 Other surface 13a Edge 13b Edge 15 Edge surface F2 Optical film laminate having raised portions on both surfaces 21 One surface 21a Edge 21b Edge 22 First raised portion 23 Other surface 23a Edge 24 Second raised portion 25 Edge surface BF Base film RM Raw material laminate RMB Raw material laminate with substrate RMR Remaining portion of raw material laminate TP Release tape CF Cover film 40 Charging device 41 Laser light 42 Discharge device 50 Sheet-to-sheet type manufacturing apparatus 51, 54, 59 Conveying device 52 Laminating device 52a Laminating roller 53 Charging device 55 Base 56 Laser cutting device 57 Discharge device 58 Peeling device 58a Bonding section 58b Peeling roller or peeling bar 60 Sheet-web type manufacturing device 61, 69 Conveying device 62 Laminating device 62a Laminating roller 63 Charging device 65 Base 66 Laser cutting device 67 Discharge device 68 Peeling device 68a Peeling roller or peeling bar 70 Web-web type manufacturing device 72 Laminating device 72a Laminating roller 73 Charging device 75 Base 76 Laser cutting device 77 Discharge device 78 Peeling device 78a Peeling roller or peeling bar

Claims

1. An optical film laminate of any shape, in which a first resin film is laminated on one side of an optical functional layer containing one or more films and a second resin film is laminated on the other side, the optical film laminate having a first raised portion at an end of the first resin film and a second raised portion at an end of the second resin film at a position corresponding to the end of the first resin film, and the height of the first raised portion and the height of the second raised portion are different.

2. The optical film laminate according to claim 1, wherein one of the height of the first protrusion and the height of the second protrusion is 1 μm.

3. The optical film stack of claim 1, wherein the sum of the height of the first ridge and the height of the second ridge is less than 20% of the thickness of the optical film stack in the portion without these ridges.

4. The optical film laminate according to claim 3, wherein the sum of the height of the first raised portion and the height of the second raised portion is 35 μm or less.

5. The optical film laminate according to claim 1, wherein an end surface of the optical film laminate between the first raised portion and the second raised portion is an inclined surface.

6. The optical film laminate according to claim 1, wherein one of the first resin film and the second resin film is a surface protection film, and the other of the first resin film and the second resin film is a release liner.

7. The optical film stack of claim 6, wherein the release liner has a ridge height of zero.

8. The optical film laminate according to claim 1, wherein the optical film laminate has an irregular shape.

9. A method for producing an optical film laminate according to any one of claims 1 to 8, comprising the steps of: transporting a raw material laminate in which a first resin film is laminated on one side of an optical functional layer containing one or more films and a second resin film is laminated on the other side; laminating a substrate on either the first resin film or the second resin film of the raw material laminate to obtain a raw material laminate with substrate; charging the raw material laminate, the substrate, or the raw material laminate with substrate, or a combination of these with static electricity to bring the substrate and the raw material laminate into close contact; forming a cut surface of any shape in the raw material laminate using laser light; removing static electricity from the raw material laminate with substrate; and peeling off the one or more optical film laminates having the cut surface of any shape from the substrate.

10. The method according to claim 9, wherein the raw material laminate is a sheet-like laminate.

11. The method of claim 9, wherein the substrate is a web-like substrate.

12. The method of claim 9, wherein the substrate is a non-stick substrate.

13. The method according to claim 9, wherein the amount of static electricity applied is such that the substrate and the raw material laminate do not peel off when the cut surface is formed by the laser light.

14. The method according to claim 13, wherein the amount of static electricity is in the range of -10 kV to -0.5 kV, or in the range of 0.5 kV to 10 kV.

15. The method according to claim 14, wherein the amount of static electricity is greater than or equal to -4.0 kV and less than or equal to -0.5 kV.

16. The method according to claim 9, wherein the substrate laminated to either one of the first resin film or the second resin film in the step of obtaining a raw laminate with substrate is a reused substrate that has been peeled off in the step of peeling off one or more of the optical film laminates having the cut surface of any shape from the substrate.

17. An apparatus for manufacturing an optical film laminate according to any one of claims 1 to 8, comprising: a conveying device for conveying a raw material laminate in which a first resin film is laminated on one side of an optical functional layer including one or more films and a second resin film is laminated on the other side; a lamination device for laminating a substrate on either one of the first resin film or the second resin film of the raw material laminate to produce a raw material laminate with substrate; a charging device for charging the raw material laminate, the substrate, or the raw material laminate with substrate, or a combination of these, with static electricity in order to bring the substrate and the raw material laminate into close contact; a laser cutting device for cutting the raw material laminate with substrate to form one or more of the optical film laminates of any shape; a static elimination device for removing static electricity from the raw material laminate with substrate; and a peeling device for peeling off the one or more of the optical film laminates of any shape from the substrate.

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