TW201801921A - Optical laminate and method of producing optical film piece using the optical laminate - Google Patents

Abstract

To provide an optical laminate capable of preventing the contamination of an optical film to be a product even in a cutting process by laser irradiation, and to provide a method of producing an optical film piece including a cutting process by laser irradiation, which is a manufacturing method capable of preventing the surface contamination of an optical film piece to be a product. The optical laminate of the present invention comprises an optical film and a protective sheet disposed to be peeled on at least one side of the optical film. The optical film includes a polarizing plate, and a surface protective film or separator disposed on at least one side of the polarizing plate.

Description

Optical laminated body and manufacturing method of optical film using the optical laminated body

The present invention relates to an optical laminated body and a method for manufacturing an optical film using the optical laminated body.

Conventionally, in image display devices such as liquid crystal display devices, various optical films, such as a polarizing film or a retardation film, have been used. By providing these optical films, the image display device exhibits desired image display characteristics. An optical film is generally manufactured by cutting an optical film having a specific product shape from a large-area mother sheet (for example, Patent Document 1). As one of the methods for cutting the optical film, cutting with laser light irradiation is often used. However, in the case where the optical film is cut using laser light, a problem occurs that smoke, dust, and the like are generated from the irradiated portion of the laser light. The generated smoke, dust, etc. adhere to the surface of the optical film and cause pollution. The use of the contaminated optical film in the steps after obtaining the optical film will cause the manufacturing equipment to be contaminated, resulting in a reduction in product yield. In order to cope with such problems, operations such as irradiating with laser light under suction and cleaning the membrane after cutting have been performed, but even these operations have made it difficult to ensure sufficient cleanliness. In addition, the above-mentioned operation complicates the steps. [Prior Art Document] [Patent Document] [Patent Document 1] Japanese Patent Laid-Open No. 11-231129

[Problems to be Solved by the Invention] The present invention has been made in order to solve the above-mentioned previous problems, and its main object is to provide a method for preventing contamination of an optical film that becomes a product even if it is used for a cutting step using laser light irradiation. An optical laminated body, and a method for manufacturing an optical film including a cutting step using laser light irradiation, which can prevent the surface of the optical film becoming a product from being contaminated. [Technical means to solve the problem] The optical multilayer body of the present invention includes an optical film and a protective sheet releasably disposed on at least one side of the optical film; the optical film is provided with a polarizing plate and at least one of the polarizing plates. Side surface protective film or optical film of release film. Another aspect of the present invention provides a method for manufacturing an optical film. The manufacturing method is a method for manufacturing an optical film from the optical laminate, and includes the steps of cutting the optical laminate by irradiating the optical laminate with laser light; and peeling the protective sheet from the optical laminate. [Effects of the Invention] According to the present invention, it is possible to provide an optical laminated body. The optical laminated system is provided with a protective sheet on the optical film, and can prevent the optical film Pollution. Moreover, the manufacturing method of the optical film of this invention is the manufacturing method of the optical film using the said optical laminated body sheet, According to this manufacturing method, the optical film itself can be prevented from being polluted.

A. Optical laminated body FIG. 1 is a schematic cross-sectional view of an optical laminated body according to an embodiment of the present invention. The optical multilayer body 100 includes an optical film 110 and protective sheets 120 a and 120 b disposed on the optical film 110. The protective sheets 120a and 120b are detachably arranged. The protective sheet can be disposed on one side of the optical film or on both sides. Preferably, as shown in the example, the protective sheets 120 a and 120 b are disposed on both sides of the optical film 110. In the optical laminated body of the present invention, the protective film is arranged on the optical film to prevent contamination of the optical film. The optical laminated body can be provided in any appropriate step in a state including a protective sheet. In one embodiment, the optical laminated body is provided in a cutting step using laser light irradiation. Typically, this step is a step of irradiating the optical laminated body with laser light, and cutting the optical laminated body including the optical film into an optical laminated body sheet having a desired product shape. As long as an optical laminated body having a protective sheet is used as the object to be processed, it is possible to prevent smoke, dust, and the like (hereinafter also simply referred to as smoke and the like) generated by laser light irradiation from adhering to the optical film (optical film). Since the said protective sheet is arrange | positioned peelably, it can be peeled and discarded at arbitrary appropriate points. The optical film after the protective sheet is peeled off can be used as a product or a semi-product while maintaining cleanliness. In one embodiment, an optical film including a polarizing plate and a surface protective film or a barrier film disposed on at least one side of the polarizing plate is used as the optical film. In FIG. 1, an optical film 110 including a polarizing plate 111 and surface protective films 112 disposed on both sides of the polarizing plate is used. The surface protective film 112 is a film for protecting a polarizing plate, and is preferably configured to be peelable. That is, the optical multilayer body of this embodiment is characterized in that a protective sheet for protecting a polarizing plate and a protective sheet for protecting an optical film including a polarizing plate and a surface protective film are used in combination. As long as such an optical laminate is used, it is possible to prevent contamination of the surface protective film due to laser light irradiation. The polarizing plate may be used in a step of manufacturing an image display device in a state protected by a surface protective film. At this time, as long as the optical film (polarizing plate / surface protection) protected by a surface protective film that maintains cleanliness is used, Membrane), it is possible to prevent contamination of the manufacturing apparatus and decrease in yield due to the contamination. In addition, although not shown, a polarizing plate typically includes a polarizing element and a protective layer. As described above, the "surface protective film" as used herein refers to a film that temporarily protects a polarizing plate, and is different from a protective layer (a layer that protects a polarizing element) provided in a polarizing plate. In one embodiment, the optical laminated body has a long shape. (Protective sheet) Examples of the material for forming the protective sheet include cellulose resins such as diacetyl cellulose and triethyl cellulose, (meth) acrylic resins, cycloolefin resins, and olefins such as polypropylene. Ester resins such as resins, polyethylene terephthalate resins, polyamide resins, polycarbonate resins, and copolymer resins thereof. In addition, as the protective sheet, methacrylate, polyethylene naphthalate (PEN), polyarylate, polystyrene (PS), polyetheretherketone, polyfluorene, polyetherfluorene, polyether A film made of a resin such as fluorene imine, polyether fluorene, or the like. In the case where the optical laminated body is provided with protective sheets on both sides of the optical film, the two protective sheets may be formed of the same material, respectively, or may be formed of different materials. The thickness of the protective sheet is preferably 10 μm to 350 μm, and more preferably 12 μm to 50 μm. A protective sheet having a thickness in this range can also effectively function as a support, and the optical laminated body provided with the protective sheet has excellent transportability. In the case where the optical laminated body is provided with protective sheets on both sides of the optical film, the two protective sheets may be respectively the same thickness or different thicknesses. In one embodiment, the protective sheet and the optical film are bonded together via any appropriate adhesive. In another embodiment, the protective sheet is held on the optical film by friction. The peeling force of the protective sheet with respect to the optical film is preferably more than 0 N / 20 mm and 2 N / 20 mm or less, and more preferably 0.005 N / 20 mm to 2 N / 20 mm. If it is in such a range, peeling and displacement of a protective sheet can be prevented in the cutting step by irradiation with laser light. In one embodiment, when a protective sheet is disposed on both sides of the optical film, the peeling force of one protective sheet with respect to the optical film is different from the peeling force of the other protective sheet with respect to the optical film. After the step, the workability when peeling the protective sheet is excellent. The peeling force was measured by a method according to JIS Z0237: 2000 (tensile speed: 300 mm / min, peeling angle: 180 °, measurement temperature: 23 ° C). (Optical Film) As the optical film, any appropriate optical film can be used. In one embodiment, as described above, a laminated body of a polarizing plate and a surface protective film and / or a separator is used as the optical film. A surface protection film or a release film is releasably laminated on the polarizing plate via any appropriate adhesive. A polarizing plate typically includes a polarizing element and a protective layer disposed on at least one side of the polarizing element. The polarizing element is typically composed of a resin film containing a dichroic substance. Examples of the dichroic material include iodine and organic dyes. These can be used individually or in combination of 2 or more types. Preferably, iodine is used. As the resin for forming the resin film, any appropriate resin can be used. Preferably, a polyvinyl alcohol-based resin is used. Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol and an ethylene-vinyl alcohol copolymer. Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. The ethylene-vinyl alcohol copolymer is obtained by saponifying an ethylene-vinyl acetate copolymer. The polarizing element preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The single transmittance (Ts) of the polarizing element is preferably 39% or more, more preferably 39.5% or more, even more preferably 40% or more, and even more preferably 40.5% or more. In addition, the theoretical upper limit of the monomer transmittance is 50%, and the practical upper limit is 46%. In addition, the unit transmittance (Ts) is a Y value after visibility correction is performed by measuring a 2-degree field of view (C light source) in JIS Z8701, and can be measured using, for example, a micro-spectroscopy system (manufactured by Lambda Vision, LVmicro). The polarization degree of the polarizing element is preferably 99.9% or more, more preferably 99.93% or more, and even more preferably 99.95% or more. The thickness of the polarizing element can be set to any appropriate value. The thickness is preferably 30 μm or less, more preferably 25 μm or less, still more preferably 20 μm or less, and even more preferably 10 μm or less. On the other hand, the thickness is preferably 0.5 μm or more, and more preferably 1 μm or more. The polarizing element is typically obtained by subjecting the resin film to various treatments such as swelling treatment, stretching treatment, dyeing treatment using the dichroic substance, crosslinking treatment, cleaning treatment, and drying treatment. When performing various processes, the resin film may be a resin layer formed on a substrate. Examples of the material for the formation of the protective layer include cellulose resins such as diacetyl cellulose and triethyl cellulose, (meth) acrylic resins, cycloolefin resins, olefin resins such as polypropylene, and polymers Ester resins such as ethylene terephthalate resins, polyamide resins, polycarbonate resins, and copolymer resins thereof. The thickness of the protective layer is preferably 10 μm to 100 μm. It is also possible to perform a hard coat or anti-reflection treatment as a surface treatment layer, or a treatment for the purpose of diffusion or anti-glare on the surface of the above-mentioned protective layer without the laminated polarizing element. The surface protective film is typically bonded to a polarizing element via an adhesive layer. Examples of the material for forming the surface protective film for protecting the polarizing plate include ester resins such as polyethylene terephthalate resins, cycloolefin resins such as olefin resins, and olefins such as polypropylene. Based resins, polyamide based resins, polycarbonate based resins, copolymer resins thereof, and the like. An ester resin (particularly, a polyethylene terephthalate resin) is preferred. The thickness of the surface protection film is typically 20 μm to 250 μm, and preferably 30 μm to 150 μm. The peeling force of the surface protective film with respect to the polarizing plate is preferably more than 0 N / 20 mm and 2 N / 20 mm or less, and more preferably 0.005 N / 20 mm to 2 N / 20 mm. When the above-mentioned protective sheet is disposed on the side opposite to the polarizing plate of the surface protective film, the peeling force of the protective sheet from the surface protective film is preferably smaller than the peeling force of the surface protective film from the polarizing plate. Examples of the material for forming the separator include ester resins such as polyethylene terephthalate resins, cycloolefin resins such as olefin resins, olefin resins such as polypropylene, and polyfluorene. Amine-based resins, polycarbonate-based resins, and copolymer resins thereof. An ester resin (particularly, a polyethylene terephthalate resin) is preferred. The thickness of the separator is typically 20 μm to 250 μm, and preferably 30 μm to 150 μm. The peeling force of the separation film with respect to the polarizing plate is preferably more than 0 N / 20 mm and 2 N / 20 mm or less, and more preferably 0.005 N / 20 mm to 2 N / 20 mm. In one embodiment, the peeling force of the separation film from the polarizing plate is smaller than the peeling force of the surface protective film from the polarizing plate. When the protective sheet is disposed on the side opposite to the polarizing plate of the separator, the peeling force of the protective sheet from the separator is preferably smaller than the peeling force of the separator from the polarizer. B. Manufacturing method of optical film The manufacturing method of the optical film of the present invention includes the steps of cutting the optical laminated body sheet by irradiating the optical laminated body with laser light, and peeling the protective sheet from the optical laminated body sheet. step. According to the manufacturing method of the present invention, by providing the optical laminated body provided with the protective sheet in a cutting step by irradiation with laser light, it is possible to prevent the smoke and the like generated by the laser light from adhering to the optical film (optical film). The optical laminated body can be obtained by laminating the protective sheet on the optical film. As the lamination method, any appropriate method can be adopted. As described above, the optical film and the protective sheet may be laminated via an adhesive, or the protective sheet may be held on the optical film by friction. The cutting step using laser light irradiation is a step of obtaining a plurality of optical laminated body sheets from the optical laminated body. The shape of the optical laminated body sheet can be set to any appropriate shape according to the use of the optical film sheet. In one embodiment, the optical laminate is cut to obtain a plurality of optical laminates. In another embodiment, a plurality of optical laminated body sheets are obtained by cutting the optical laminated body. Furthermore, when the optical laminated body is provided with a protective sheet only on one side of the optical film, the surface on which the laser light is radiated is preferably the protective sheet side surface of the optical laminated body. The laser light is preferably light having a wavelength of 200 nm to 11000 nm. As the laser for the cutting step using laser light irradiation, any appropriate laser can be adopted. For example, any appropriate laser can be used. Specific examples include gas lasers such as CO ₂ lasers and excimer lasers; solid lasers such as YAG (Yttrium Aluminum Garnet) lasers; and semiconductor lasers. Irradiation conditions (output conditions, moving speed, and number of times) of laser light can be arbitrarily appropriate depending on the cutting target, cutting depth, and the like. As a method of peeling the protective sheet, any appropriate method can be adopted. For example, in the case where the protective sheet after the laser light irradiation is elongated, a method in which the protective sheet is rolled up and peeled off from the optical film may be adopted. In the case where the protective sheet after the laser light irradiation is not long and cannot be taken up, a method of transferring the protective sheet to a peeling tape may be adopted. FIG. 2 is a schematic diagram illustrating an example of a method for manufacturing an optical film according to an embodiment of the present invention. In one embodiment, as shown in FIG. 2, a long optical film 110 is used, and the above-mentioned stroke is continuously performed while the optical film 110 is carried. Hereinafter, this embodiment will be specifically described in order from the step of sending out the optical film. First, the long optical film 110 is sent out, and the long protective sheets 120a and 120b are laminated on the optical film 110 while the optical film 110 is transported to form the long optical laminated body 100 (step a). In this embodiment, an upper protective sheet 120a is laminated on the upper side of the optical film 110, and a lower protective sheet 120b is laminated on the lower side of the optical film 110. The upper protection sheet 120a and the lower protection sheet 120b may be laminated at the same time, or may be laminated at different times. In such a case where the protective sheet is peeled at different points, it is preferable that the peeling force of the protective sheet (the upper protective sheet in the example shown in the figure) to be peeled off from the optical film is smaller than the protective sheet to be peeled off later ( In the example in the figure, the peeling force of the lower protective sheet) with respect to the optical film. In addition, the lower protective sheet 120b can function as a transport substrate for the optical laminated body sheet 100 'and the optical film sheet 110' that are cut in the subsequent steps. Then, the optical laminated body 100 formed in step a is provided for a step of cutting the optical laminated body sheet 100 '(step b). Here, a plurality of optical laminated body sheets 100 'are cut out from the optical laminated body 100 by the above-mentioned laser light irradiation. In addition, FIG. 2 shows a form in which the optical laminated body is cut to obtain a plurality of optical laminated body sheets. In addition, the so-called optical laminated body sheet 100 'refers to a laminated body sheet including an optical film that becomes a product or a semi-product after implementing the manufacturing method of the present invention. It is necessary to pay attention to the cutting residue that is discarded in the next step as described later. Slice 100 ''. In step b, it is preferable to separate at least the upper protective sheet 120a and the optical film 110 into a part of the optical laminated body sheet 100 'and other cutting residues 100''. In addition, it is preferable that the lower protection sheet 120b is not completely separated and maintains a long shape. Therefore, it is preferable that the cut-off piece 100 ″ is a laminate of the upper protective sheet 120 a and the optical film 110 and does not include the lower protective sheet 120 b. If the lower protective sheet 120b maintains a long shape, the lower surface protective film 120b can function as a transport substrate for the optical laminated body sheet 100 'and the optical film sheet 110' that have been cut off. The state in which the lower protection sheet 120b is not completely separated also includes a state in which the lower protection sheet 120b is half-cut. Then, the protective sheets 120a and 120b are peeled (step c). It is preferable to peel off from the upper protective sheet 120a first. When the upper protective sheet 120a is peeled off, the optical laminated body sheet 100 'may include the upper protective sheet 120a and the upper protective sheet 120a located in a portion other than the optical laminated sheet 100' (cut residue 100 ''). It may be peeled at different times, or it may be peeled at different times. Preferably, it is peeled at different points as shown in the example. In the example shown in the figure, the optical laminated body sheet 100 'is provided with the peeling (peeling c1) of the upper protective sheet 120a and the upper protective sheet 120a located at a portion other than the optical laminated sheet 100' (cut residue 100 '') The peeling (peeling c2) was performed at different times. Peeling c1 and peeling c2 may be performed in the order of peeling c1 and peeling c2 as shown in the example, or may be performed in the order of peeling c2 and peeling c1. It is preferable to perform peeling c1 and peeling c2 in the order shown in the example. The optical laminated body sheet 100 ′ includes peeling (peeling c1) of the upper protective sheet 120 a, and the upper protective sheet 120 a is transferred to the peeling tape 200 using, for example, a peeling tape 200. As the peeling tape, a tape having a specific adhesive force can be used. The peeling tape is preferably long. In the embodiment shown in FIG. 2, the strip-shaped peeling tape 200 that is continuously sent out is brought into contact with the optical laminated body sheet 100 ′ that is conveyed while being placed on the lower protective sheet 120 b, from the optical laminated body. The sheet 100 'peels off the upper protective sheet 120a in order. The peeling force of the protective sheet with respect to the optical film is preferably equal to or lower than the peeling force of the protective sheet (the upper protective sheet in the example of the figure) peeled by the peeling tape with respect to the peeling tape. The difference between the peeling force of the protective sheet with respect to the optical film and the peeling force of the protective sheet with the peeling tape with respect to the peeling tape is preferably more than 0 N / 20 mm and 3 N / 20 mm or less, more preferably 0.005 N / 20 mm to 2 N / 20 mm, more preferably 0.001 N / 20 mm to 0.4 N / 20 mm. If it is this range, a protective sheet can be peeled well. The peeling force of the protective sheet peeled by the peeling tape with respect to the peeling tape is preferably 0.005 N / 20 mm to 4 N / 20 mm, and more preferably 0.005 N / 20 mm to 3 N / 20 mm. The peeling (peeling c2) of the upper protective sheet 120a located on the part other than the optical laminated body sheet 100 'can be performed by winding up the upper protective sheet 120a on the part other than the optical laminated body sheet 100'. When peeling c2, it is preferable to peel simultaneously the upper side protective sheet 120a and the optical film 110 corresponding to the cutting residue 100 '' in a laminated state. After c2 is peeled off, the optical film 110 ′ can be transported while being placed on the lower protective sheet 120 b. After the upper protective sheet 120a is peeled, the lower protective sheet 120b is peeled. The lower protection sheet 120b is peeled off, for example, while the lower protection sheet 120b is rolled up. In the above-described manner, the optical film 110 ′ cut into a specific shape is manufactured from the long optical film 110. The obtained optical film 110 'can be used as a product or a semi-product in a state where the cleanliness is maintained while preventing contamination caused by laser light irradiation. [Industrial Applicability] The manufacturing method of the present invention can be preferably used when manufacturing an optical film such as a polarizing element plate.

100‧‧‧ Optical Laminate
100'‧‧‧ optical laminated body sheet
100``‧‧‧ cropped fragments
110‧‧‧optical film
110'‧‧‧Optical diaphragm
111‧‧‧ polarizing plate
112‧‧‧surface protection film
120‧‧‧protective film
120a‧‧‧upper side protection sheet
120b‧‧‧ underside protection sheet
200‧‧‧ peeling tape

FIG. 1 is a schematic cross-sectional view of an optical multilayer body according to an embodiment of the present invention. FIG. 2 is a schematic diagram illustrating an example of a method for manufacturing an optical film according to an embodiment of the present invention.

100‧‧‧ Optical Laminate

110‧‧‧optical film

111‧‧‧ polarizing plate

112‧‧‧surface protection film

120a‧‧‧upper side protection sheet

120b‧‧‧ underside protection sheet

Claims (2)

An optical multilayer body includes an optical film and a protective sheet releasably disposed on at least one side of the optical film; and the optical film includes a polarizing plate and a surface protective film or at least one side of the polarizing plate. Optical film of isolation film. A method for manufacturing an optical film, which is a method for manufacturing an optical film from an optical multilayer as described in claim 1, and includes the steps of: irradiating laser light to the optical multilayer to cut the optical multilayer; and The optical laminated body sheet peeled the protective sheet.