KR20200091871A - Cutting method and manufacturing method of laminated film - Google Patents

Abstract

The method of cutting the laminated film is a method of cutting the laminated film FX in which the laminated films FX in which a plurality of resin layers S3, S5, and S4 having different materials are laminated are cut along the cutting line C, and laminated. The plurality of resin layers S3, S5, and S4 are cut by scanning the cutting line C of the film FX with a plurality of laser beams L1 and L2 having different wavelengths. Specifically, among the plurality of resin layers (S3, S5, S4), the resin layers (S4, S5) exhibiting a photolysis reaction by absorption of the first laser light (L1) are cut with the first laser light (L1). , Among the plurality of resin layers S3, S5, and S4, the resin layer S3 exhibiting a photolysis reaction by absorption of the second laser light L2 is cut into the second laser light L2.

Description

Cutting method and manufacturing method of laminated film

The present invention relates to a method for cutting and manufacturing a laminated film in which a plurality of resin layers having different materials are laminated.

This application claims priority based on Japanese Patent Application No. 2017-235351 filed on December 7, 2017 and Japanese Patent Application No. 2018-208864 filed on November 6, 2018, the contents of which Use it here.

For example, an optical film such as a polarizing plate or a retardation film (phase difference plate) is attached to an optical display panel such as a liquid crystal panel or an organic EL panel. In general, for these optical films, a long film is unwound from a roll of fabric and a cut (cutting) of the unrolled film to a width or length corresponding to the optical display panel is used.

For cutting the optical film, a blade is conventionally used. However, in the case of cutting by cutting with a blade, foreign matters such as film scraps are likely to occur during cutting. In addition, when the optical film with such a foreign substance adheres to the optical display panel, a display defect or the like may be generated in the optical display panel.

Therefore, in recent years, cutting (cutting) of an optical film using a laser beam is performed (for example, refer patent documents 1-3). Specifically, in Patent Document 1, in cutting a laminate comprising a resin film and a single layer or multiple layers of functional layers, a first cutting step for cutting a portion of the functional layer and the resin film by laser and a cutting blade A method for producing a resin film medium having a second cutting step for cutting the remaining resin film is disclosed.

On the other hand, in Patent Document 2, a method of manufacturing a polarizing plate that cuts a layer constituting another polarizing plate with only the release film leaving the polarizing plate as a laser from the surface protection film layer to the layer immediately before the layer containing the laser light low absorption film. Disclosed is a method of cutting and subsequently cutting a layer comprising a laser light low absorption film with a cutter.

On the other hand, Patent Document 3, the method of cutting the polarizer by cutting the high absorbance film by irradiation of laser light, and forming a groove in the low absorption film, and a tearing process for tearing the low absorption film along the groove It is disclosed.

Patent Document 1: Japanese Patent No. 5359356 Patent Literature 2: Japanese Patent No. 44743939 Patent Document 3: Japanese Patent No. 581300

A typical polarizing plate is a type in which a polyvinyl alcohol (PVA) layer serving as a polarizer is sandwiched between, for example, a triacetyl cellulose (TAC) layer serving as an upper protective layer and a cycloolefin polymer (COP) layer serving as a lower protective layer. It constitutes the laminated film.

When such a laminated film is cut by a laser beam (for example, a carbon dioxide gas laser, a wavelength of 9.4 μm), it is a relatively easy-to-cut layer (a layer having a high absorption rate of laser light) other than the COP layer. It is cut, and the cross-section quality is kept good. On the other hand, since the COP layer is a layer that is relatively difficult to cut (a layer having a low absorption rate of laser light), there is a problem that the cross-section quality deteriorates due to cutting by thermal processing due to molecular vibration.

An aspect of the present invention has been proposed in view of such conventional circumstances, and a laminated film in which a plurality of resin layers having different materials such as polarizing plates are laminated can be cut with high precision, and the cross-sectional quality of the cut laminated film is also improved. An object of the present invention is to provide a method for cutting a laminated film that can be maintained satisfactorily and a method for producing a laminated film using such a method for cutting a laminated film.

As a means for solving the above problems, according to an aspect of the present invention, as a method of cutting a laminated film in which a plurality of resin layers having different materials are stacked along a cutting line, the cutting line of the laminated film is wavelength A method of cutting a laminated film for cutting the plurality of resin layers by scanning with a plurality of different laser lights is provided.

In the method of cutting the laminated film, the first laser among the plurality of resin layers is scanned by scanning the cutting line of the laminated film with a first laser light and a second laser light having a different wavelength from the first laser light. The resin layer exhibiting a photolysis reaction by absorption of light is cut with the first laser light, and among the plurality of resin layers, the resin layer exhibiting a photolysis reaction by absorption of the second laser light is cut with the second laser light. It is also good.

In the method of cutting the laminated film, the first laser light may be laser light excited by a carbon dioxide gas laser, and the second laser light may be a laser light excited by a YAG laser, an excimer laser, or a semiconductor laser.

According to another aspect of the present invention, a method of manufacturing a laminated film in which a plurality of resin layers having different materials are stacked includes a cutting step of cutting the plurality of resin layers along a cutting line, and in the cutting step, A method of manufacturing a laminated film using any one of the above cutting methods is provided.

In the method of manufacturing the laminated film, the laminated film is a polarizing plate in which at least a cycloolefin polymer (COP) layer and a polyvinyl alcohol (PVA) layer are laminated, and the PVA layer is cut by the first laser light, The COP layer may be cut by the second laser light.

In the method of manufacturing the laminated film, the laminated film further includes a triacetyl cellulose (TAC) layer, the COP layer, the PVA layer, and the TAC layer are polarizing plates laminated in this order, and the TAC The layer and the PVA layer may be cut with the first laser light, and the COP layer may be cut with the second laser light.

In the manufacturing method of the laminated film, the second laser light may be a laser light excited by a YAG laser, an excimer laser, or a semiconductor laser.

In the method of manufacturing the laminated film, the laminated film may be a laminated film for a flexible image display device including at least two or more selected from a circular polarizing plate, a window film, and a touch sensor.

As described above, according to the aspect of the present invention, by using a laser beam having different wavelengths, a plurality of resin layers of different materials are laminated by cutting the laminated film by photolysis processing with less heat, thereby forming a laminated film. The resin layer of can be cut with high precision, and it is also possible to keep the cross-sectional quality of the cut laminated film satisfactorily.

1 is a cross-sectional view showing a laminated structure of a polarizing plate.
2 is a perspective view showing an example of a laser processing apparatus.
3 is a perspective view showing a specific configuration of a laser irradiation device.
4 is a cross-sectional view for explaining the cutting process of the polarizing plate.
5 is a graph showing transmittance of light having a wavelength of 2.0 to 14.0 μm in COP, PVA, TAC and PET.
6 is a graph showing the transmittance of COP for light having a wavelength of 200 to 500 μm.
7 is a perspective view showing another example of the laser processing apparatus.
It is sectional drawing which shows the laminated structure of the polarizing plate with which the surface protection film was bonded.
9 is a cross-sectional view for explaining the cutting process of the polarizing plate shown in FIG. 8.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described with reference to drawings.

In addition, in the following description, the drawings used in the following description may be enlarged to show portions that are characteristic for convenience, and the dimensional ratio of each component is not the same as actual. In addition, the materials, dimensions, etc. which are illustrated in the following description are only examples, and the present invention is not necessarily limited to them, and can be appropriately changed and carried out without changing the gist thereof.

(Cutting method of laminated film)

In the method of cutting a laminated film to which the present invention is applied, when a laminated film in which a plurality of resin layers of different materials are laminated is cut along a cutting line, the cutting line of the laminated film is scanned with a plurality of laser beams having different wavelengths, thereby It is characterized by cutting the resin layer.

In this embodiment, as a specific example of the method for cutting a laminated film to which the present invention is applied, the case where the polarizing plate (laminated film) FX shown in Fig. 1 is cut is described as an example.

In the polarizing plate FX, as shown in FIG. 1, the uppermost layer of the polarizing plate FX is protected by the surface protection film S2. The surface protection film S2 is a sheet piece of a predetermined size together with the polarizing plate FX by a cutting process, and is peeled and removed from the polarizing plate FX after being bonded to the liquid crystal panel.

As such a surface protection film (S2), a polyethylene terephthalate (PET) film can be used.

The polarizing plate FX has a laminated structure in which the polarizer layer S5 (resin layer) is sandwiched between a pair of protective layers S3 and S4 (resin layer). Specifically, the polarizing plate FX of the present embodiment is a cycloolefin polymer (COP) layer as a protective layer (S3) on the lower layer side, a polyvinyl alcohol (PVA) layer as a polarizer layer (S5), and an upper layer side protection. As the layer (S4), a triacetyl cellulose (TAC) layer constitutes a laminated film laminated in this order.

In addition, the laminated structure of the polarizing plate FX shown in FIG. 1 is just an example, and is not necessarily limited to such a laminated structure, and is a laminated film in which a plurality of resin layers (films) of different materials are laminated, each resin layer ( Film) can be performed by appropriately changing the material or thickness used.

(Flexible image display device)

The manufacturing method of the laminated film to which this invention is applied can be used conveniently when manufacturing the laminated film (laminated film for flexible image display devices) applied to a flexible image display device.

The flexible image display device includes a laminated film for a flexible image display device and an organic EL display panel, and a laminate for a flexible image display device is disposed on the viewer side with respect to the organic EL display panel, and bending is freely configured.

As the laminate for a flexible image display device, it is sufficient to include at least two or more selected from a window film (hereinafter, sometimes referred to as "window"), a circular polarizing plate, and a touch sensor. In addition, the window, the circular polarizing plate, and the touch sensor all have flexibility (flexibility).

In addition, the stacking order of the window, the circular polarizing plate, and the touch sensor is arbitrary, but the configuration is stacked in the order of the window, the circular polarizing plate, and the touch sensor from the viewer side, or in the order of the window, the touch sensor, and the circular polarizing plate from the viewer side. It is preferable to form it by lamination. When the circular polarizing plate is present on the viewing side of the touch sensor, it is preferable because the pattern of the touch sensor becomes difficult to visualize and the visibility of the display image is improved.

In addition, a window, a circular polarizing plate, and a touch sensor can be laminated by bonding using an adhesive or an adhesive. In addition, a light blocking pattern may be formed on at least one surface of a window, a circular polarizing plate, and a layer of any one of the touch sensors.

(window)

The window is disposed on the viewing side of the flexible image display device, and serves as a protective layer that protects other components from environmental changes such as impact from outside or temperature and humidity.

Conventionally, as such a protective layer, glass has been used, but the window in the flexible image display device is not rigid and rigid like glass, but includes a transparent substrate having the flexibility described above. The transparent base material may include a hard coat layer on at least one surface.

(Transparent description)

The transparency of the transparent substrate used for the window is preferably 70% or more of the visible light transmittance, and more preferably 80% or more. The transparent base material is not particularly limited as long as it is a transparent polymer film, and any material can be used.

Specifically, polyolefins such as polyethylene, polypropylene, polymethylpentene, norbornene or cycloolefin-based derivatives having units of monomers containing cycloolefins; (Modified) celluloses such as diacetyl cellulose, triacetyl cellulose, and propionyl cellulose; Acrylics such as methyl methacrylate (co)polymer; Polystyrenes such as styrene (co)polymers; Acrylonitrile-butadiene-styrene copolymers; Acrylonitrile-styrene copolymers; Ethylene-vinyl acetate copolymers; Halogen-containing polymers such as polyvinyl chlorides and polyvinylidene chlorides; Polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, and polyarylate; Polyamides such as nylon; Polyimides, such as polyimides, polyamideimides, and polyetherimides; Polysulfones such as polyether sulfones and polysulfones; Polyvinyl alcohols; Polyvinyl acetals; Polyurethanes; Films containing polymers such as epoxy resins can be used. Moreover, an unstretched film containing these polymers or a uniaxial or biaxially stretched film can be used.

In addition, these polymers may be used alone or in combination of two or more. Especially, it is preferable to use polyamide film, polyamideimide film or polyimide film, polyester film, olefin film, acrylic film, and cellulose film excellent in transparency and heat resistance.

It is preferable to disperse inorganic particles such as silica, organic fine particles, and rubber particles in the transparent substrate. Further, in the transparent substrate, a colorant such as a pigment or a dye, a fluorescent brightener, a dispersing agent, a plasticizer, a heat stabilizer, a light stabilizer, an infrared absorber, an ultraviolet absorber, an antistatic agent, an antioxidant, a lubricant, and a blending agent such as a solvent may be contained. . The thickness of the transparent base material is preferably 5 to 200 μm, and more preferably 20 to 100 μm.

(Hard coat)

The window may be provided with a hard coat layer on at least one surface in order to prevent damage to the surface of the transparent substrate (in order to improve scratch resistance). The thickness of the hard coat layer is not particularly limited, but may be, for example, 2 to 100 μm. When the thickness of the hard coat layer is less than 2 μm, it becomes difficult to secure sufficient scratch resistance. On the other hand, when the thickness of the hard coat layer exceeds 100 µm, flexibility may decrease, and a problem of curling due to curing shrinkage may occur.

The hard coat layer can be formed by curing a hard coat composition containing a reactive material that forms a crosslinked structure by irradiating active energy rays or thermal energy. Especially, it is preferable to irradiate active energy rays to form a crosslinked structure, that is, by active energy ray curing. The active energy ray is defined as an energy ray capable of decomposing a compound generating an active species to generate an active species. Examples of the active energy ray include visible rays, ultraviolet rays, infrared rays, X rays, α rays, β rays, γ rays, and electron rays. Especially, it is especially preferable to use ultraviolet rays.

The hard coat composition contains at least one polymerized product of a radically polymerizable compound and a cationic polymerizable compound. The radically polymerizable compound is a compound having a radically polymerizable group. The radically polymerizable group may be any functional group capable of generating a radical polymerization reaction, and examples thereof include a group containing a carbon-carbon unsaturated double bond. Specifically, a vinyl group, a (meth)acryloyl group, etc. are mentioned. In addition, when two or more radically polymerizable compounds have radically polymerizable groups, these radically polymerizable groups may be the same or different.

It is preferable that the number of radically polymerizable groups the radically polymerizable compound has in one molecule is two or more from the viewpoint of improving the hardness of the hard coat layer. As a radically polymerizable compound, it is preferable that it is a compound which has a (meth)acryloyl group from the point of reactivity, and it is called a polyfunctional acrylate monomer which has 2-6 (meth)acryloyl groups in 1 molecule. It is preferable to use oligomers having a molecular weight of several hundred to several thousand in a molecule called a compound or an epoxy (meth)acrylate, urethane (meth)acrylate, or polyester (meth)acrylate. Do. In addition, it is preferable to include at least one selected from epoxy (meth)acrylate, urethane (meth)acrylate, and polyester (meth)acrylate.

The cationic polymerizable compound is a compound having a cationic polymerizable group such as an epoxy group, an oxetanyl group, and a vinyl ether group. The number of cationically polymerizable groups of the cationically polymerizable compound in one molecule is preferably two or more, and more preferably three or more, from the viewpoint of improving the scratch resistance of the hard coat layer.

Moreover, as a cationically polymerizable compound, it is preferable that it is a compound which has at least 1 type of cyclic ether group among an epoxy group and an oxetanyl group as a cationically polymerizable group. The cyclic ether group is preferable in that shrinkage due to the polymerization reaction is small. In addition, the compound having an epoxy group in the cyclic ether group is easy to obtain a compound of various structures from the market, and does not adversely affect the scratch resistance and durability of the obtained hard coat layer.

Moreover, when a radically polymerizable compound and a cationically polymerizable compound are included as a hard coat composition, there is an advantage that compatibility with the radically polymerizable compound is also easy to control. Among the cyclic ether groups, the oxetanyl group tends to have a high degree of polymerization as compared to an epoxy group, is low-toxicity, and accelerates the rate of network formation from the cationically polymerizable compound of the obtained hard coat layer, and is unreacted even in a region mixed with a radically polymerizable compound. It has an effect of not leaving the monomer of the film in the membrane. In addition, there are advantages such as forming an independent network.

Examples of the cationic polymerizable compound having an epoxy group include polyglycidyl ethers of polyhydric alcohols having an alicyclic group; Alicyclic epoxy resins obtained by epoxidizing a cyclohexene ring or a cyclopentene ring-containing compound with a suitable oxidizing agent such as hydrogen peroxide or peracid; Aliphatic epoxy alcohols, or aliphatic epoxy resins such as polyglycidyl ethers of alkylene oxide adducts, polyglycidyl esters of aliphatic long-chain polybasic acids, homopolymers and copolymers of glycidyl (meth)acrylates; Bisphenols such as bisphenol A, bisphenol F and hydrogenated bisphenol A, or alkylene oxide adducts thereof; Glycidyl ethers and novolac epoxy resins produced by reaction of a derivative such as a caprolactone adduct with epichlorohydrin; And glycidyl ether type epoxy resins derived from bisphenols.

The hard coat composition may contain a polymerization initiator. Examples of the polymerization initiator include a radical polymerization initiator, a cationic polymerization initiator, and a radical and cationic polymerization initiator. Among them, it can be appropriately selected and used depending on the type of the polymerizable compound used. These polymerization initiators are decomposed by at least one of active energy ray irradiation and heating to generate radicals or cations to advance radical polymerization and cationic polymerization.

The radical polymerization initiator may be capable of releasing a substance that initiates radical polymerization by at least one of active energy ray irradiation and heating. For example, examples of the thermal radical polymerization initiator include organic peroxides such as hydrogen peroxide and perbenzoic acid, and azo compounds such as azobisbutylnitrile.

Examples of the active energy ray radical polymerization initiator include a type 1 radical polymerization initiator in which radicals are generated by decomposition of molecules, and a type 2 radical polymerization initiator that coexists with tertiary amines to generate radicals through a hydrogen-releasing reaction, and each independently It can be used as or in combination.

The cationic polymerization initiator may be capable of releasing a substance that initiates cationic polymerization by at least one of active energy ray irradiation and heating. As the cationic polymerization initiator, for example, an aromatic iodonium salt, an aromatic sulfonium salt, a cyclopentadienyl iron (II) complex, or the like can be used. These can initiate cationic polymerization either by active energy ray irradiation or by heating due to the difference in structure.

The polymerization initiator may contain 0.1 to 10% by weight based on 100% by weight of the total hard coat composition. When the content of the polymerization initiator is less than 0.1% by weight, it is difficult to sufficiently progress curing, and it becomes difficult to realize mechanical properties or adhesion of the finally obtained coating film.

On the other hand, when the content of the polymerization initiator is more than 10% by weight, there is a case where poor adhesion, cracking, and curling occurs due to curing shrinkage.

The hard coat composition may further contain at least one selected from solvents and additives. The solvent may be any one capable of dissolving or dispersing the polymerizable compound and the polymerization initiator, and any solvent conventionally known as a solvent for the hard coat composition in the art can be used without limitation. Examples of the additives include inorganic particles, leveling agents, stabilizers, surfactants, antistatic agents, lubricants, antifouling agents and the like.

(Circular polarizer)

The circular polarizing plate is a functional layer having a function of transmitting only the right circularly polarized component or the left circularly polarized component. For example, by converting external light incident on the display device into right circularly polarized light, and this right circularly polarized light is reflected by the organic EL panel to become left circularly polarized light, the left circularly polarized light can be blocked by a circularly polarized plate. As a result, a circular polarizing plate is used to suppress the influence of reflected light and transmit only the light emitting component of the organic EL, so that the image can be easily seen.

In order to achieve the function as circularly polarized light, a linear polarizing plate and a λ/4 phase difference plate are stacked and combined, and the angle of absorption of the linear polarizing plate and the slow axis of the λ/4 phase difference plate is theoretically 45. Although it is necessary to set it as °, practically it is good to be 45°±10°.

The linearly polarizing plate and the λ/4 retardation plate do not necessarily need to be stacked adjacent to each other, and the relationship between the absorption axis and the slow axis should just satisfy the above range. It is desirable to achieve full circular polarization for the entire wavelength. However, in practical use, it is not always necessary, so the circularly polarizing plate used in the flexible image display device may include an elliptical polarizing plate. Moreover, it is also possible to improve the visibility in the state which puts on the polarizing sunglasses by laminating|stacking the lambda /4 phase difference film on the viewing side of a linearly polarizing plate, and making outgoing light into circularly polarized light.

The linearly polarizing plate is a functional layer having a function of blocking the polarization of a vibration component perpendicular to it while passing light oscillating in the direction of the transmission axis. Further, the linear polarizer may be configured with a linear polarizer alone or a linear polarizer and a protective film adhered to at least one surface thereof. The thickness of the linear polarizing plate may be 200 μm or less, and preferably 0.5 to 100 μm. When the thickness of the linear polarizing plate exceeds 200 μm, flexibility may decrease.

The linear polarizer functions as a polarizer layer in the linear polarizer, and examples thereof include film-type polarizers produced by dyeing and stretching a polyvinyl alcohol (PVA)-based film. In addition, the dichroic dye is oriented to the PVA-based film oriented by stretching, or by being stretched while being adsorbed to the PVA molecule of the PVA-based film, the dichroic dye is oriented to exhibit polarization performance.

In the production of the film-type polarizer, in addition, other steps such as swelling, crosslinking with boric acid, washing with an aqueous solution, and drying may be performed. The stretching step and the dyeing step may be performed alone with a PVA-based film, or may be carried out in a state of being laminated with another film such as polyethylene terephthalate. As the PVA-based film to be used, it is preferable that the thickness is 10 to 100 μm and the draw ratio is 2 to 10 times.

The linear polarizing plate having the film-type polarizer as a linear polarizer and the circular polarizing plate having the linear polarizing plate have been described above. However, in order to improve the flexibility of the circular polarizing plate, the thickness of the circular polarizing plate is made thinner, and the thinner polarizer ( It is preferable to use a thin film polarizer).

An example of such a thin film polarizer is a liquid crystal coated polarizer formed by applying a liquid crystal polarizing composition. As a liquid crystal polarizing composition, what contains a liquid crystal compound and a dichroic dye compound is mentioned.

As a liquid crystal compound, it should just have the property which shows a liquid crystal state, and it is especially preferable to have a high degree of orientation state, such as a smectic phase, because it can exhibit high polarization performance. Moreover, it is preferable to have a polymerizable functional group.

The dichroic dye compound is a dye that is aligned with a liquid crystal compound and exhibits dichroism, and the dichroic dye itself may have liquid crystallinity or may have a polymerizable functional group. Any of the compounds contained in the typical liquid crystal polarizing composition has a polymerizable functional group.

Moreover, it is preferable that a liquid crystal polarizing composition contains an initiator and a solvent, and also it may contain additives, such as a dispersing agent, a leveling agent, a stabilizer, surfactant, a crosslinking agent, and a silane coupling agent.

The liquid crystal polarizing layer can be produced by applying a liquid crystal polarizing composition on an alignment film to form a liquid crystal polarizing layer. Such a liquid crystal polarizing layer has an advantage that the thickness can be made thinner than that of a film type polarizer. In that case, the thickness of the liquid crystal polarizing layer is preferably 0.5 to 10 μm, and more preferably 1 to 5 μm.

The alignment film can be produced on the substrate by, for example, applying an alignment film-forming composition on the substrate using a suitable substrate, and imparting orientation by rubbing, polarization irradiation, or the like.

The alignment film forming composition may contain, in addition to the alignment agent, a solvent, a crosslinking agent, an initiator, a dispersing agent, a leveling agent, a silane coupling agent, and the like.

As the alignment agent, for example, polyvinyl alcohols, polyacrylates, polyamic acids, and polyimides can be used. When applying photo-alignment (polarization irradiation), it is preferable to use an alignment agent containing a cinnamate group. The polymer used as the alignment agent may have a weight average molecular weight of about 10,000 to 1,000,000. The thickness of the alignment film is preferably 5 to 10000 nm, and particularly preferably 10 to 500 nm, since the orientation regulating force is sufficiently exhibited, which is more preferable.

The liquid crystal polarizing layer formed on the substrate provided with the alignment film may be peeled from the substrate, and a second substrate is bonded to a laminate in which the substrate, the alignment film and the liquid crystal polarizing layer are laminated, and the liquid crystal polarizing layer is attached to the second substrate. You can also transfer. When the liquid crystal polarizing layer is transferred to the second substrate, the second substrate may serve as a protective substrate, a retardation plate, and a transparent substrate for the window.

As the protective film, a transparent polymer film may be used, and materials and additives exemplified as the transparent substrate can be used. Especially, it is preferable to use a cellulose type film, an olefin type film, an acrylic film, and a polyester type film. Further, a coating type protective film obtained by coating and curing a cationic curing composition such as an epoxy resin or a radical curing composition such as acrylate may be used.

Further, if necessary, plasticizers, ultraviolet absorbers, infrared absorbers, colorants such as pigments and dyes, fluorescent brighteners, dispersants, heat stabilizers, light stabilizers, antistatic agents, antioxidants, lubricants, solvents, and the like may be included. The thickness of the protective film may be 200 µm or less, and preferably 1 to 100 µm. When the thickness of the protective film exceeds 200 µm, flexibility may decrease. In addition, the protective film may also serve as a window.

The λ/4 retardation plate is a film that provides a retardation of λ/4 in a direction (direction in the plane of the film) that goes directly in the direction of travel of the incident light. The λ/4 retardation plate may be, for example, a stretched retardation plate produced by stretching a polymer film such as a cellulose-based film, an olefin-based film, or a polycarbonate-based film. In addition, if necessary, phase retarders, plasticizers, ultraviolet absorbers, infrared absorbers, colorants such as pigments or dyes, fluorescent brighteners, dispersants, heat stabilizers, light stabilizers, antistatic agents, antioxidants, lubricants, solvents, etc. It may be. The thickness of the stretched retardation plate may be 200 μm or less, and is preferably 1 to 100 μm. When the thickness of the stretched retardation plate exceeds 200 μm, flexibility may decrease.

Moreover, as such a lambda /4 phase difference plate, a liquid crystal coating type phase difference plate formed by applying and forming a liquid crystal composition may be used. The liquid crystal composition for forming the liquid crystal coating type retardation plate includes a liquid crystal compound having properties of exhibiting liquid crystal states such as nematic, cholesteric, and smectic. Any of the liquid crystal compounds contained in the liquid crystal composition has a polymerizable functional group.

In addition, the liquid crystal composition may contain an initiator, a solvent, a dispersant, a leveling agent, a stabilizer, a surfactant, a crosslinking agent, a silane coupling agent, and the like. The liquid crystal coating-type retardation plate can be produced by coating-curing a liquid crystal composition on an alignment film and forming a liquid crystal retardation layer as described in the liquid crystal polarizing layer.

The liquid crystal-coated retardation plate can be formed to have a thinner thickness than the stretched retardation plate. Specifically, the thickness of the liquid crystal polarizing layer is preferably 0.5 to 10 μm, and more preferably 1 to 5 μm. The liquid crystal-coated retardation plate may be peeled off from the substrate, transferred, and laminated, or the substrate may be laminated as it is. The base material may also serve as a protective film, a retardation plate, and a transparent base material for the window.

In general, a retardation plate exhibits a large birefringence as the wavelength is shorter and a smaller birefringence as the wavelength is longer. In this case, since a phase difference of λ/4 cannot be provided in the entire visible light region, it is often designed to be λ/4 in the vicinity of 560 nm with high visibility. The in-plane retardation of the retardation plate is preferably 100 to 180 nm, more preferably 130 to 150 nm.

It is preferable to use a reverse dispersion λ/4 retardation plate made of a material having an opposite birefringence wavelength dispersion characteristic for a circularly polarizing plate because it can improve visibility. When such a material is used as a stretched retardation plate, for example, those described in Japanese Patent Laid-Open No. 2007-232873 can be used. In the case of a liquid crystal coating type retardation plate, one described in Japanese Patent Application Laid-open No. 2010-30979 can be used.

As another method, a technique of obtaining a broadband λ/4 phase difference plate by combining a λ/4 phase difference plate and a λ/2 phase difference plate is also known (for example, refer to Japanese Patent Laid-Open Publication No. Hei 10-90521). The λ/2 retardation plate is made of the same material and method as the λ/4 retardation plate. In that case, the combination of the stretched retardation plate and the liquid crystal coated retardation plate is arbitrary, but both are preferable because the film thickness can be reduced by using the liquid crystal coated retardation plate.

In order to increase the visibility of the circularly polarizing plate, a method of laminating a positive C plate is also known (for example, see Japanese Unexamined Patent Publication No. 2014-224837). The positive C plate may be a liquid crystal coating type retardation plate, or an elongated retardation plate. The retardation in the thickness direction is preferably -200 to -20 nm, more preferably -140 to -40 nm.

(Touch sensor)

The touch sensor is a typical member used as an input means of a flexible image display device. As the touch sensor, for example, various methods such as a resistive film method, a surface acoustic wave method, an infrared method, an electromagnetic induction method, and a capacitive method can be used, and among them, it is preferable to use a capacitive method.

The capacitive touch sensor is divided into an active area and an inactive area located on an outer portion of the active area. The active area is an area corresponding to an area (display area) on which a screen is displayed on the display panel, and is an area where a user's touch is detected. On the other hand, the inactive area is an area corresponding to an area (non-display section) in which a screen is not displayed on the image display device.

The touch sensor includes a substrate having flexible characteristics, a sensing pattern formed in an active region of the substrate, and a sensing pattern formed in an inactive region of the substrate and connected to an external driving circuit through the sensing pattern and the pad portion. Can.

As the substrate having flexible properties, the same material as the transparent substrate of the window can be used. It is preferable from the viewpoint of suppressing cracking of the touch sensor that the toughness of the touch sensor is 2,000 MPa or more. More preferably, the toughness is 2,000% to 30,000%. Here, "toughness" is a property obtained from a stress-strain curve (%) obtained by a tensile test of a polymer material. That is, a tensile test is performed to obtain a stress-strain (%) curve from the start of stress addition to the fracture point of the test polymer material, and is defined as the area of the obtained curve.

The sensing pattern may include a first pattern formed in the first direction and a second pattern formed in the second direction. The first pattern and the second pattern are arranged in different directions. The first pattern and the second pattern are formed on the same layer, and in order to sense a touched point, each pattern must be electrically connected. In the first pattern, each unit pattern is connected to each other through a seam. On the other hand, the second pattern has a structure in which each unit pattern is separated from each other in an island shape. Therefore, in order to electrically connect the second pattern, a separate bridge electrode is required.

As the sensing pattern, a known transparent electrode material can be used. For example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium zinc tin oxide (IZTO), cadmium tin oxide (CTO), PEDOT (poly(3,4-ethylenedioxythiophene) ), carbon nanotubes (CNT), graphene, metal wires, and the like. These may be used alone or in combination of two or more. Especially, it is preferable to use ITO.

The metal used for the metal wire is not particularly limited, and examples thereof include silver, gold, aluminum, copper, iron, nickel, titanium, telenium, and chromium. These may be used alone or in combination of two or more.

The bridge electrode may be formed on the sensing pattern through an insulating layer. The bridge electrode is formed on the substrate, and an insulating layer and a sensing pattern can be formed thereon. The bridge electrode may be formed of the same material as the sensing pattern, or may be formed of a metal such as molybdenum, silver, aluminum, copper, palladium, gold, platinum, zinc, tin, titanium, or an alloy of two or more of them. have.

Since the first pattern and the second pattern must be electrically insulated, an insulating layer is formed between the sensing pattern and the bridge electrode. The insulating layer can be formed only between the seam of the first pattern and the bridge electrode. In addition, it may be formed in a structure of a layer covering the sensing pattern. In the latter case, the bridge electrode can be connected to the second pattern through a contact hole formed in the insulating layer.

The touch sensor appropriately compensates for a difference in transmittance between a patterned patterned area and a non-patterned patterned area, specifically, a difference in light transmittance caused by a difference in refractive index in these areas. As a means for doing so, an optical control layer may be further included between the substrate and the electrode.

The optical control layer may include an inorganic insulating material or an organic insulating material. The optical control layer may be formed by coating a photocurable composition comprising a photocurable organic binder and a solvent on a substrate. In addition, the photocurable composition may contain inorganic particles. The refractive index of the optical control layer is increased by the inorganic particles.

As the photocurable organic binder contained in the photocurable composition, for example, a copolymer of each monomer such as an acrylate monomer, a styrene monomer, or a carboxylic acid monomer can be used. The photocurable organic binder may be, for example, a copolymer containing different repeating units such as an epoxy group-containing repeating unit, an acrylate repeating unit, and a carboxylic acid repeating unit.

Examples of the inorganic particles contained in the photocurable composition include zirconia particles, titania particles, and alumina particles. In addition, the photocurable composition may contain, for example, each additive such as a photopolymerization initiator, a polymerizable monomer, and a curing aid.

(Adhesive layer)

Each layer (window, circular polarizing plate, touch sensor) forming the laminate for the flexible image display device and the film member (linear polarizing plate, λ/4 retardation plate, etc.) constituting each layer are formed through an adhesive layer formed of an adhesive. Can be joined.

Examples of the adhesive include water-based adhesives, organic solvent-based, solvent-free adhesives, solid adhesives, solvent volatilization-type adhesives, moisture-curable adhesives, heat-curable adhesives, anaerobic curing type, active energy ray-curable adhesives, curing agent mixed adhesives, and hot-melt adhesives , Pressure-sensitive adhesives (adhesives), re-wet type adhesives and the like can be used. Among them, water-based adhesives, solvent volatilization-type adhesives, active energy ray-curable adhesives, and pressure-sensitive adhesives are often used.

The thickness of the adhesive layer can be appropriately adjusted according to the required adhesive force, and is preferably 0.01 to 500 µm, more preferably 0.1 to 300 µm. When the laminate for a flexible image display device has a plurality of adhesive layers, the thickness and type of each adhesive layer may be the same or different.

The water-based adhesive mainly includes water, and water-dispersible polymers such as polyvinyl alcohol-based polymers, water-soluble polymers such as starch, ethylene-vinyl acetate-based emulsions, and styrene-butadiene-based emulsions can be used as the main polymer. Moreover, you may mix|blend a crosslinking agent, a silane type compound, an ionic compound, a crosslinking catalyst, an antioxidant, a dye, a pigment, an inorganic filler, an organic solvent, etc. in addition to water and a main polymer.

In the case of bonding with a water-based solvent volatilization-type adhesive, adhesion can be imparted by injecting the water-based solvent volatilization-type adhesive between the layers to be adhered and bonding the layers to be dried.

The thickness of the adhesive layer when using an aqueous adhesive is preferably 0.01 to 10 μm, more preferably 0.1 to 1 μm. When a water-based adhesive is used for a plurality of adhesive layers, the thickness and type of each adhesive layer may be the same or different.

The active energy ray-curable adhesive can be formed by curing an active energy ray curing composition containing a reactive material that irradiates active energy rays to form an adhesive layer. The active energy ray-curable composition may contain at least one polymerized product of a radically polymerizable compound and a cationic polymerizable compound.

Specific examples of the radically polymerizable compound and the cationic polymerizable compound herein are the same as the radically polymerizable compound and the cationic polymerizable compound included in the above-mentioned hard coat composition. Especially, it is preferable to use a radically polymerizable compound. In particular, it is preferable to use a compound having an acryloyl group as the radical polymerizable compound contained in the active energy ray-curable adhesive used for forming the adhesive layer. Further, in order to lower the viscosity of the active energy ray-curable adhesive itself, it is preferable to include a monofunctional compound as a radically polymerizable compound.

The cationic polymerizable compound is the same as described in the above-mentioned hard coat composition.

Especially, it is preferable to use an epoxy compound as a cationically polymerizable compound used for an active energy ray hardening adhesive agent. Moreover, in order to lower the viscosity as an adhesive composition, it is preferable to include a monofunctional compound as a reactive diluent.

The active energy ray-curable adhesive may further include a polymerization initiator. Examples of the polymerization initiator are a radical polymerization initiator, a cationic polymerization initiator, a radical and a cationic polymerization initiator, and can be appropriately selected and used depending on the type of the polymerizable compound. Specific examples of these radical polymerization initiators, cationic polymerization initiators, and radical and cationic polymerization initiators include those described for the polymerization initiators included in the above-mentioned hard coat composition.

In addition, the active energy ray curing composition may include an ion trapping agent, an antioxidant, a chain transfer agent, an adhesion imparting agent, a thermoplastic resin, a filler, a flow viscosity modifier, a plasticizer, an antifoaming agent solvent, an additive, a solvent, and the like. In the case of using an active energy ray-curable adhesive, the active energy ray curing composition is applied to one or both sides of the adherend, and then bonded, and then adhered by irradiating and curing the active energy ray through either or both of the adhered layers. can do. When the active energy ray-curable adhesive is used, the thickness of the adhesive layer is preferably 0.01 to 20 μm, and more preferably 0.1 to 10 μm. When using multiple layers of an active energy ray-curable adhesive, the thickness and type of each layer may be the same or different.

As an adhesive, according to the kind of main polymer, it is classified into acrylic adhesive, urethane adhesive, rubber adhesive, silicone adhesive, etc., for example. Moreover, it can also be used for bonding of each layer of the laminated body for flexible image display devices. In addition to the main polymer, the pressure-sensitive adhesive may contain a crosslinking agent, a silane compound, an ionic compound, a crosslinking catalyst, an antioxidant, a tackifier, a plasticizer, a dye, a pigment, or an inorganic filler.

The adhesive layer is formed by dissolving and dispersing each component constituting the adhesive in a solvent to obtain an adhesive composition, and applying the adhesive composition on a substrate and drying the adhesive layer. The pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive composition may be applied directly to the pressure-sensitive adhesive composition, or may be transferred to a substrate formed separately.

In addition, it is preferable to use a release film to cover the adhesive surface before adhesion.

When using an active energy ray-curable adhesive, the thickness of the adhesive layer is preferably 0.1 to 500 μm, and more preferably 1 to 300 μm. When using multiple layers of an adhesive, the thickness and kind of each layer may be the same or may differ.

(Shading pattern)

The light-shielding pattern can be applied as at least a part of a bezel or a housing of a flexible image display device. The light-shielding pattern hides the wiring arranged at the edge of the flexible image display device, making it difficult to visually recognize, thereby improving the visibility of the image.

The light-shielding pattern may be in the form of a single layer or multiple layers. The color of the light shielding pattern is not particularly limited, and has various colors such as black, white, and metal. The light-shielding pattern may be formed of a pigment for realizing color, and a polymer such as acrylic resin, ester resin, epoxy resin, polyurethane, and silicone. Moreover, you may use these individually or as a mixture of 2 or more types.

The light-shielding pattern can be formed by various methods such as printing, lithography, and inkjet. The thickness of the light shielding pattern is preferably 1 to 100 μm, and more preferably 2 to 50 μm. In addition, the light-shielding pattern can also give a shape such as a slope to the thickness direction.

The film thickness of the film, functional layer, device, etc. can be measured using a general film thickness measurement method. As the film thickness measurement method, for example, cross-section observation using an electron microscope, a method using a step meter, a film thickness measurement method using a light interference method such as a spectral interference method or a laser interference method, and a film thickness measurement method using a spectroscopic ellipsometry And the like.

<Laser processing equipment>

2 is a perspective view showing an example of the laser processing apparatus 30 used in the cutting process of this embodiment.

The laser processing apparatus 30 shown in FIG. 2 includes a laser irradiation apparatus (irradiation means) 31 that irradiates the laser beam L with the polarizing plate FX, and a cutting line C of the polarizing plate FX. Accordingly, a laser scanning device (scanning means) 32 for scanning the laser light L and a driving control device (driving control means) 33 for controlling the driving of each part are provided.

3 is a perspective view showing a specific configuration of the laser irradiation device 31.

The laser irradiation apparatus 31 shown in FIG. 3 includes: a first laser light source 34A that emits the first laser light L1; The second laser light source 34B emitting the second laser light L2, the first laser light L1 and the second laser light L2 are transmitted or reflected, so that the first laser light L1 and the second laser light L2 are transmitted or reflected. A dichroic mirror (light path converting means) 35 for emitting the laser light L2 toward the same direction; A condensing lens (condensing optical system) 36 for condensing the first laser light L1 and the second laser light L1 toward the polarizing plate FX; A first arranged in the optical path between the dichroic mirror 35 and the condensing lens 36 to adjust the irradiation positions of the first laser light L1 and the second laser light L2 irradiated to the polarizing plate FX. And second position adjustment mechanisms 37A, 37B (position adjustment means).

In the laser processing apparatus 30 shown in Fig. 2, the first laser light L1 and the second laser light L2 having different wavelengths are collectively described as the laser light L without discrimination. In the following description, when there is no need to specifically distinguish between the first laser light L1 and the second laser light L2, it is assumed that the laser light L is integrated and handled.

The first laser light source 34A outputs the first laser light L1 by a pulse oscillation method. The second laser light source 34B outputs the second laser light L2 having a different wavelength from the first laser light L1 by a pulse oscillation method. Specifically, in this embodiment, a carbon dioxide gas (CO ₂ ) laser oscillator is used as the first laser light source 34A, and a YAG laser oscillator is used as the second laser light source 34B. In this case, the first laser light L1 is an infrared laser light having a wavelength of 9.4 µm, and the second laser light L2 is an ultraviolet laser light having a wavelength of 266 nm.

As the second laser light source 34B, an excimer laser oscillator (ultraviolet laser light with a wavelength of 157 to 351 nm), a semiconductor laser (LD: laser diode) excited solid pulse laser oscillator (infrared laser light with a wavelength of 2940 nm), pulsed fiber A laser oscillator (infrared laser light with a wavelength of 3 µm), a CO pulse laser oscillator (infrared laser light with a wavelength of 5.5 µm), or the like can also be used.

The dichroic mirror 35 transmits either one of the first laser light L1 and the second laser light L2 having different wavelengths (the first laser light L1 in this embodiment). Then, the other laser beam (in this embodiment, the second laser beam L2) is reflected.

When the arrangement of the first laser light source 34A and the second laser light source 34B is reversed, the first laser light L1 (one laser light) is reflected as the dichroic mirror 35, What transmits the 2nd laser beam L2 (the other laser beam) may be used. It is also possible to use a dichroic prism instead of the dichroic mirror 35.

The condenser lens 36 includes, for example, an fθ lens, and the fθ lens has a function of constantly correcting the scanning speed of the laser light L(L1, L2).

The first and second positioning mechanisms 37A, 37B include, for example, a galvanometer mirror, and a scanner capable of biaxially scanning the laser light L(L1, L2) in a plane parallel to the polarizing plate FX. It has a function as (injection means).

Specifically, the first position adjustment mechanism 37A adjusts the angle of the mirror 38a and the mirror 38a that reflects the laser light L(L1, L2) toward the second position adjustment mechanism 37B. It has an actuator 39a to be said to have a structure in which a mirror 38a is attached to a rotating shaft 40a rotatable around the Z axis of the actuator 39a.

On the other hand, the second position adjustment mechanism 37B is a mirror that reflects the laser light L(L1, L2) reflected by the mirror 38a of the first position adjustment mechanism 37A toward the condensing lens 36 ( It has a structure in which a mirror 38b is attached to a rotating shaft 40b that has a 38b) and an actuator 39b that adjusts the angle of the mirror 38b and is rotatable around the Y axis of the actuator 39b.

In the first and second position adjustment devices 37A and 37B, the angles of the respective mirrors 38a and 38b are adjusted by controlling the driving of each actuator 39a and 39b by the drive control device 33 described later. , It is possible to adjust the irradiation position of the laser light L(L1, L2) irradiated to the polarizing plate FX by biaxial scanning.

For example, in the first and second position adjustment mechanisms 37A and 37B, the laser light indicated by the solid line in FIG. 3 is adjusted by adjusting the irradiation position of the laser light L(L1, L2) irradiated to the polarizing plate FX. L(L1, L2)) is condensed at the condensing point Qa on the polarizing plate FX, or the laser light L(L1, L2) represented by the dashed-dotted line in Fig. 3 is condensing point Qb on the polarizing plate FX ), or the laser light L(L1, L2) indicated by the two-dot chain line in FIG. 3 can be focused at the light-converging point Qc on the polarizing plate FX.

As shown in Fig. 2, the laser scanning device 32 includes a slider mechanism (not shown) using, for example, a linear motor, and under the control of the drive control device 33 described later, the laser irradiation device ( 31) the width direction (X-axis direction) (V1) of the polarizing plate FX, the longitudinal direction (Y-axis direction) (V2) of the polarizing plate FX, and the thickness direction (Z-axis direction) of the polarizing plate FX ( V3) can be moved in each direction.

The laser scanning device 32 is not necessarily limited to the operation of moving the laser irradiation device 31, but may be a operation of moving the polarizing plate FX itself. Also in this case, it is possible to scan (trace) the laser light L(L1, L2) from the laser irradiation device 31 along the cutting line C of the polarizing plate FX. Moreover, both the laser irradiation apparatus 31 and the polarizing plate FX may be operated to move.

The drive control device 33 is electrically connected to the first and second laser light sources 34A and 34B included in the laser irradiation device 31 to drive the first and second laser light sources 34A and 34B. Control. Specifically, the drive control device 33 switches driving (ON/OFF) of the first laser light source 34A and the second laser light source 34B. The drive control device 33 controls the output of the laser light L(L1, L2) or the number of pulse oscillations emitted from the first and second laser light sources 34A, 34B.

Thereby, the 1st laser beam L1 and the 2nd laser beam L2 can be selectively irradiated with respect to the polarizing plate FX. In addition, it is possible to variably adjust the amount of energy per unit area of the laser light L(L1, L2) irradiated to the polarizing plate FX.

The drive control device 33 is electrically connected to the laser scanning device 32 to control the moving speed of the laser scanning device 32. Thereby, while adjusting the scanning speed of the laser light L(L1, L2) variably, the amount of energy per unit area of the laser light L(L1, L2) irradiated to the polarizing plate FX is variably adjusted. It becomes possible.

The drive control device 33 is electrically connected to the first and second position adjustment mechanisms 37A and 37B included in the laser irradiation device 31, so that the first and second position adjustment mechanisms 37A and 37B are provided. To control the drive. Thereby, it becomes possible to adjust the irradiation position of the laser beam L(L1, L2) irradiated to the polarizing plate FX by biaxial scanning.

<Cutting process of polarizing plate>

It is particularly preferable for the laminated film to be cut according to the cutting method of the present invention to include at least a layer containing a cycloolefin polymer such as a COP layer in order to express the effects of the present invention.

When the COP layer uses a cutting method commonly used for cutting a film, such as a cutting method using a carbon dioxide gas laser, a cut surface having good completeness as described above cannot be obtained. On the other hand, in the case of using the cutting method to which the present invention is applied to a laminated film containing a COP layer, particularly a polarizing plate comprising a COP layer, it is possible to exert a remarkable effect.

Specifically, as a method of cutting a laminated film to which the present invention is applied, the cutting process of the polarizing plate FX using the laser processing apparatus 30 will be described with reference to FIGS. 4A and 4B. 4(a) and 4(b) are cross-sectional views sequentially showing the cutting process of the polarizing plate FX.

In this embodiment, as a polarizing plate FX, a TAC layer, a PVA layer (film-type polarizer = polarizer layer), and a COP layer are demonstrated using the cutting process of the polarizing plate (laminated film) laminated|stacked in this order as an example.

When cutting the polarizing plate FX using the laser processing apparatus 30, first, as shown in FIG. 4(a), while irradiating the first laser light L1 to the polarizing plate FX, the polarizing plate The first laser light L1 is scanned along the cutting line C of (FX) (referred to as the first scan). The cutting line C should just be set on the polarizing plate FX so that a sheet-like sheet piece of a desired size is obtained after cutting.

At this time, among the layers (S3, S5, and S4) constituting the polarizing plate FX, the protective layer (TAC layer) S4 and the polarizer layer on the upper layer side showing a photolysis reaction by absorption of the first laser light L1 (PVA layer) S5 is cut with the first laser light L1. In addition, in the first scan by the first laser light L1, it is preferable to set the focal position U1 of the first laser light L1 to a position deeper than the polarizer layer (PVA layer) S5.

Thereby, the cutting groove V along the cutting line C is formed in the polarizing plate FX. The cutting groove V is formed to a depth that divides the protective layer (TAC layer) S4 and the polarizer layer (PVA layer) S5 on the upper layer side.

Next, as shown in FIG. 4(b), while irradiating the second laser light L2 with respect to the polarizing plate FX, the second laser light L2 along the cutting line C of the polarizing plate FX Is injected (called the second injection).

At this time, of each layer (S3, S5, S4) constituting the polarizing plate FX, the second protective layer (COP layer) S3 on the lower layer side showing the photolysis reaction by absorption of the second laser light L2 is second. It is cut with laser light (L2). In the second scan by the second laser light L2, it is preferable to set the focal position U2 of the second laser light L2 to a position deeper than the protective layer (COP layer) S3 on the lower layer side. .

Thereby, the cutting groove V is formed deeper in the depth direction from the position where the polarizer layer (PVA layer) S5 is divided, and at a depth that divides the protective layer (COP layer) S3 on the lower layer side. Therefore, in this cutting process, it is possible to cut the polarizing plate FX along the cutting line C by the second scanning.

"COP", "PVA", "TAC", "which are the constituent materials of the protective layer (S3) on the lower layer, the polarizer layer (S5), the protective layer (S4) on the upper layer, and the surface protective film (S2) PET”, the transmittance of light having a wavelength of 2.0 to 14.0 μm is shown in FIG. 5. About "COP", the transmittance|permeability with respect to the light of wavelength 200-500 micrometers is shown in FIG.

As shown in Fig. 5, for the first laser light L1 (carbon dioxide gas laser) having a wavelength of 9.4 µm, COP shows little light absorption (transmittance is almost 100%), and PVA, TAC other than COP, It was found that PET exhibits some degree of light absorption. On the other hand, as shown in Fig. 6, it was found that the COP exhibits a certain degree of light absorption for the second laser light L2 (YAG laser, fourth harmonic) having a wavelength of 266 nm.

Therefore, when it is desired to cut the polarizing plate FX with only the first laser light L1, the upper protective layer (TAC layer) S4 and the polarizer layer (PVA layer) S5 are relatively easy to cut layers (product 1 Because it is a layer with a high absorption of laser light (L1), it is cut by photolysis processing with less heat generation. On the other hand, the protective layer (COP layer) S3 on the lower layer side is a layer that is relatively difficult to cut (a layer having a low absorption rate of the first laser light L1), so that it is cut by thermal processing due to molecular vibrations, and is cross-sectioned. The quality deteriorates.

In contrast, in the cutting method to which the present invention is applied, the upper protective layer (TAC layer) S4 and the polarizer layer (PVA layer) S5 are cut with the first laser light L1, and the lower protective layer ( COP layer) S3 is cut with the second laser light L2. In this case, since any of the layers S3, S5, and S4 are cut by photolysis processing with little heat generation, it is possible to obtain a cut surface with good completeness in the polarizing plate FX after cutting.

In addition, when the polarizing plate FX is to be cut only by the second laser light L2, the polarizing plate FX is cut by photolysis processing with less heat generation, but since the laser output is weak, the processing speed is significantly slowed down. Therefore, the cutting method using only the second laser light L2 is industrially inefficient.

As described above, in the cutting method of the present embodiment, the polarizing plate FX is cut by using the first and second laser lights L1 and L2 having different wavelengths to cut the polarizing plate FX by photolysis processing with less heat generation. It is possible to cut with precision along the cutting line (C). Moreover, since the completeness of the cut surface of the polarizing plate FX is good without damaging the polarizing plate FX, it is also possible to cope with further narrowing of the display area in the optical display device.

(Other embodiments)

In addition, this invention is not necessarily limited to the thing of the said embodiment, It is possible to make various changes in the range which does not deviate from the meaning of this invention.

Specifically, in the cutting step, instead of using the laser processing apparatus 30 shown in FIG. 2, it is also possible to cut the polarizing plate FX using, for example, the laser processing apparatus 30A shown in FIG. 7. 7 is a perspective view showing the configuration of the laser processing device 30A. In addition, in the following description, about the part equivalent to the said laser processing apparatus 30, description is abbreviate|omitted and it is assumed that the same code|symbol is attached|subjected in a figure.

<Laser processing equipment>

The laser processing device 30A shown in FIG. 7 uses the first laser irradiation device 31A and the second laser light L2 that irradiate the first laser light L1 instead of the laser irradiation device 31. It is the structure provided with the 2nd laser irradiation apparatus 31B irradiated. That is, the laser processing device 30A separately includes a first laser irradiation device 31A having a first laser light source 34A and a second laser irradiation device 31B having a second laser light source 34B. Doing.

When the 1st laser irradiation apparatus 31A and the 2nd laser irradiation apparatus 31B are separately provided, the 1st and 2nd laser irradiation apparatus 31A, 31B is from the structure of the said laser irradiation apparatus 31, The dichroic mirror 35 is omitted, and the first or second laser light L1, L2 is emitted from the first or second laser light sources 34A, 34B toward the first position adjustment mechanism 37A. It is good to make it a structure.

The first laser irradiation device 31A and the second laser irradiation device 31B are separately operated by the laser scanning device 32, and are separately controlled by the drive control device 33.

When the polarizing plate FX is cut using the laser processing apparatus 30A shown in FIG. 7, first, the first laser irradiation apparatus 31A irradiates the polarizing plate FX with the first laser light L1, The first laser light L1 is scanned along the cutting line C of the polarizing plate FX.

Thereby, among the layers (S3, S5, S4) constituting the polarizing plate FX, the protective layer (TAC layer) S4 and the polarizer layer (PVA layer) S5 on the upper layer side are first laser light L1. ).

Next, the second laser irradiation device 31B scans the second laser light L2 along the cutting line C of the polarizing plate FX while irradiating the second laser light L2 against the polarizing plate FX. do.

Thereby, the protective layer (COP layer) S3 on the lower layer side of each of the layers S3, S5, and S4 constituting the polarizing plate FX is cut with the second laser light L2. Therefore, in this cutting process, it is possible to cut the polarizing plate FX along the cutting line C by the second scanning, similarly to the case where the laser processing apparatus 30 shown in Fig. 2 is used.

In the case of using the laser processing apparatus 30A shown in FIG. 7, the second by the second laser irradiation apparatus 31B while following the scanning of the first laser light L1 by the first laser irradiation apparatus 31A. The laser light L2 can be scanned. Therefore, when the laser processing apparatus 30A shown in FIG. 7 is used, it is possible to cut the polarizing plate FX at a higher speed than when the laser processing apparatus 30 shown in FIG. 2 is used.

In addition, according to an embodiment of the present invention, a pressure-sensitive adhesive layer is newly provided by applying an adhesive to the lower layer side protective layer (COP layer) S3 with respect to the sheet piece cut out from the polarizing plate FX. It may be bonded to a liquid crystal panel, or a retardation film, a brightness enhancing film, or the like may be further bonded.

For example, the polarizing plate FX' shown in FIG. 8 includes a protective layer (COP layer) S3 on the lower side sandwiching a polarizer layer (PVA layer) S5 and a protective layer (TAC layer) S4 on the upper layer side (S4). On both sides of the surface protective film (PET film) (S2), respectively, has a configuration in which peeling is freely bonded.

<Cutting process of polarizing plate>

The cutting process of the polarizing plate FX' using the laser processing apparatus 30 will be described with reference to Figs. 9A to 9C. 9(a) to 9(c) are cross-sectional views sequentially showing the cutting process of the polarizing plate FX'.

When cutting the polarizing plate FX' using the laser processing apparatus 30, first, as shown in Fig. 9A, while irradiating the first laser light L1 to the polarizing plate FX, the polarizing plate The first laser light L1 is scanned along the cutting line C of (FX) (referred to as the first scan).

At this time, among the layers (film) (S2, S3, S5, S4, and S2) constituting the polarizing plate FX', the surface protective film on the upper layer side showing a photolysis reaction by absorption of the first laser light L1 ( PET layer) (S2), the upper protective layer (TAC layer) (S4) and the polarizer layer (PVA layer) (S5) is cut with a first laser light (L1). In the first scan by the first laser light L1, it is preferable to set the focal position U1 of the first laser light L1 to a position deeper than the polarizer layer (PVA layer) S5.

Thereby, the cutting groove V'along the cutting line C is formed in the polarizing plate FX'. The cutting groove V'is formed to a depth that divides the surface protective film (PET film) S2 on the upper layer side, the protective layer (TAC layer) S4 and the polarizer layer (PVA layer) S5 on the upper layer side. do.

Next, as shown in Fig. 9B, while irradiating the second laser light L2 onto the polarizing plate FX', the second laser light (along the cutting line C of the polarizing plate FX') L2) is injected (called the second injection).

At this time, among the layers (film) (S2, S3, S5, S4, and S2) constituting the polarizing plate FX', the lower protective layer (COP) showing a photolysis reaction by absorption of the second laser light L2 Layer) S3 is cut with the second laser light L2. In the second scan by the second laser light L2, it is preferable to set the focal position U2 of the second laser light L2 to a position deeper than the protective layer (COP layer) S3 on the lower layer side. .

Thereby, the cutting groove V'is formed to a depth which divides the protective layer (COP layer) S3 on the lower layer side in the depth direction from the position where the polarizer layer (PVA layer) S5 is divided.

Next, as shown in Fig. 9(c), while irradiating the first laser light L1 onto the polarizing plate FX', the first laser light (along the cutting line C of the polarizing plate FX') ( L1) is injected (called the third injection).

At this time, among the layers (film) (S2, S3, S5, S4, and S2) constituting the polarizing plate FX', the surface protection film on the lower layer side showing a photolysis reaction by absorption of the first laser light L1 ( PET film) (S2) is cut with a first laser light (L1). In the third scan by the first laser light L1, it is preferable to set the focal position U3 of the first laser light L1 to a position deeper than the lower surface protective film (PET film) S2. Do.

Thereby, the cutting groove V'is the depth which divides the lower surface side protective film (PET film) S2 in the depth direction from the position where the lower layer side protective layer (COP layer) S3 is divided. It is formed of. Therefore, in this cutting process, it is possible to cut the polarizing plate FX' along the cutting line C by the third scan.

As described above, in the cutting method of the present embodiment, the polarizing plate (') is cut by using the first and second laser lights (L1, L2) having different wavelengths, and the polarizing plate (FX') is cut by photolysis processing with less heat generation. It is possible to cut FX') precisely along the cutting line C. Moreover, it is possible to keep the cross-sectional quality of the cut polarizing plate FX' satisfactorily.

In the present embodiment, when the laser light used in the third scan is used as the third laser light, the first laser light L1 described above is used for the third laser light, but the surface protection on the lower layer side is used. As long as the laser light can cut the film (PET film) S2 by a photolysis reaction, it is also possible to use laser light having a wavelength different from the first and second laser lights L1 and L2. In addition, it is the same also for the fourth and subsequent injections.

That is, in the method for cutting a laminated film to which the present invention is applied, among the plurality of resin layers constituting the laminated film, laser light having a wavelength that can be cut by a photolysis reaction is appropriately selected and used according to the resin layer being cut. It is good to do.

In addition, the method of cutting the laminated film to which the present invention is applied is not limited to the case of cutting the polarizing plates FX and FX' described above, and in the cutting step of cutting the laminated film in which a plurality of resin layers having different materials are laminated. , It is possible to apply the present invention widely.

Moreover, the manufacturing method of the laminated|multilayer film to which this invention was applied can apply this invention broadly with respect to including the above-mentioned cutting process, when manufacturing the laminated|multilayer film in which the several resin layers with different materials were laminated|stacked.

As for the laminated film produced by applying the present invention, in addition to the polarizing plates FX and FX' described above, for example, optical films such as a retardation film and a brightness enhancing film can be cited. Moreover, even when the laminated film which laminated|stacked these optical films is cut|disconnected, it is possible to apply the cutting method of this invention. In addition, as an optical display panel to which these laminated films are adhered, other than a liquid crystal panel, for example, an organic EL panel may be used.

Further, depending on the material, thickness, and number of layers, etc. of the laminated film, it is possible to increase the number of scans of the laser light, or to adjust the output or scan speed of the laser light. Further, examples of the method for scanning laser light to the cutting line include a method of repeatedly scanning the laser light along the cutting line in one direction, a method of repeatedly reciprocating the laser light between the start and end points of the cutting line, and the like. have. In addition, a method of simultaneously scanning a plurality of laser lights L along a cutting line may be mentioned.

30… Laser processing device 31… Laser irradiation device (irradiation means) 32. Laser scanning device (scanning means) 33. Driving control device (drive control means) 34A… First laser light source 34B... Second laser light source 35. Dichroic mirror (optical path conversion means) 36… Condensing lens (condensing optical system) 37A… First position adjustment mechanism 37B... 2nd position adjustment mechanism FX, FX'… Polarizing plate (laminated film) S2… Surface protection film (PET film) S3… Protective layer (COP layer) S4 on the lower layer side... Protective layer on the upper side (TAC layer) S5… Polarizer layer (PVC layer) L… Laser light L1… First laser light (third laser light) L2… Second laser light C... Cutting lines U1, U2, U3… Focus position V, V'… Cutting groove

Claims (8)

As a cutting method of a laminated film for cutting a laminated film laminated with a plurality of resin layers of different materials along a cutting line,
A method of cutting a laminated film in which the plurality of resin layers are cut by scanning the cutting line of the laminated film with a plurality of laser beams having different wavelengths. The absorption line of claim 1, wherein the first laser light among the plurality of resin layers is absorbed by scanning a cutting line of the laminated film with a first laser light and a second laser light having a different wavelength from the first laser light. By cutting the resin layer showing a photolysis reaction by the first laser light, and cutting the laminated film to cut the resin layer showing a photolysis reaction by absorption of the second laser light among the plurality of resin layers with the second laser light Way. The laser beam according to claim 1 or 2, wherein the first laser light is a laser light excited by a carbon dioxide gas laser,
A method of cutting a laminated film, wherein the second laser light is a laser light excited by a YAG laser, an excimer laser or a semiconductor laser. A method of manufacturing a laminated film in which a plurality of resin layers having different materials are laminated,
And a cutting process of cutting the plurality of resin layers along a cutting line,
In the said cutting process, the manufacturing method of the laminated|multilayer film characterized by using the cutting method of any one of Claims 1-3. The laminated film of claim 4, wherein the laminated film is a polarizing plate in which at least a cycloolefin polymer (COP) layer and a polyvinyl alcohol (PVA) layer are laminated,
The PVA layer is cut by the first laser light,
The manufacturing method of the laminated film which cut|disconnects the said COP layer by the said 2nd laser beam. The method of claim 5, wherein the laminated film further comprises a triacetyl cellulose (TAC) layer, the COP layer, the PVA layer and the TAC layer is a polarizing plate laminated in this order,
The TAC layer and the PVA layer are cut by the first laser light,
The manufacturing method of the laminated film which cut|disconnects the said COP layer by the said 2nd laser beam. The method for manufacturing a laminated film according to claim 5, wherein the second laser light is laser light excited by a YAG laser, an excimer laser, or a semiconductor laser. The method of claim 4, wherein the laminated film is a laminated film for a flexible image display device including at least two selected from a circular polarizing plate, a window film, and a touch sensor.

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