JP6983072B2 - Optical film - Google Patents

Description

The present invention relates to an optical film including a cholesteric liquid crystal layer.

As a film imparted with design, an optical film on which a hologram is formed is known. Such an optical film is manufactured, for example, by a method of pressing a heated hologram original plate against a cholesteric liquid crystal film formed on an alignment film to transfer a hologram (diffraction grating or the like) (see, for example, Patent Document 1).

Further, as an optical film in which a plurality of regions having different selective reflection wavelengths are provided on the cholesteric liquid crystal layer, a sheet with an anti-counterfeit function is also known. Such a sheet is manufactured, for example, by a method of irradiating a cholesteric liquid crystal layer with ultraviolet rays in a pattern through a photomask having slits in a pattern.

Japanese Unexamined Patent Publication No. 2000-347016

However, in the method described in Patent Document 1, it is necessary to press the heated hologram original plate against the liquid crystal film, and pressure is applied to the substrate and the liquid crystal layer itself under heating, so that the substrate is deformed and the liquid crystal layer is damaged. There are problems such as the occurrence and deviation from the designed selective reflection wavelength.

The present invention has been made in view of the above-mentioned problems of the prior art, and provides an optical film capable of easily producing an optical film having a design property without damaging the liquid crystal layer. The purpose. Another object of the present invention is to provide an optical film having excellent design.

In order to achieve the above object, the present invention is an optical film having a liquid crystal layer, in which the liquid crystal material in a part of the liquid crystal layer and the liquid crystal material in another region are the same and the part of the area. Provided is an optical film characterized in that the liquid crystal material of the above and the liquid crystal material of the other region have different orientation states.

According to the method for producing an optical film invented by the inventors of the present invention, the liquid crystal layer formed on the alignment film by erasing or weakening the alignment ability of a part of the alignment film by surface treatment has the alignment ability. The liquid crystal material is not oriented in the region on the alignment film in which the above is eliminated or weakened, and a region having a different orientation state from the other regions is formed. As a result, an optical film is obtained in which a pattern is formed by regions in which the orientation state of the liquid crystal layer is different and the design is imparted. Since the regions having different alignment states of the liquid crystal layer can be formed by surface treatment of the alignment film, an optical film on which a desired pattern is formed can be easily manufactured without damaging the liquid crystal layer. be able to. In particular, when the alignment film is surface-treated, no external force is applied after the liquid crystal layer is formed, so that the substrate is not deformed or the liquid crystal layer is not damaged. Further, since the liquid crystal layer is not reheated after being formed, the selective reflection wavelength does not deviate. The surface treatment method of the alignment film includes a solvent application to a part of the alignment film _{, direct drawing with CO 2} laser light, excimer UV irradiation using a mask, and electron beam (EB) drawing. Can be mentioned. In addition, a method of imparting orientation ability by rubbing with a mask, which will be described later, can also be used.

In the optical film of the present invention, the liquid crystal material in a part of the liquid crystal layer does not have to be regularly oriented. The optical film of the present invention may be a continuous film formed by applying a liquid crystal material on the alignment film. In the optical film of the present invention, the liquid crystal material may be a cholesteric liquid crystal. The optical film of the present invention may further include a protective film.

The optical film of the present invention may be provided with a separator that can be peeled off via a glue layer on the surface of the liquid crystal layer. Further, another separator that can be peeled off via the adhesive layer may be provided on the surface of the liquid crystal layer opposite to the glue layer.

The optical film of the present invention may further include a microlens array or a lenticular lens array.

The optical film of the present invention may have a region exhibiting diffractive ability formed in the liquid crystal layer, or may further include a layer exhibiting diffractive ability. The optical film of the present invention may include a printing layer under the liquid crystal layer.

According to the present invention, an optical film having a simple structure and excellent design can be obtained.

1 (a) to 1 (f) are explanatory views for explaining an embodiment of the method for manufacturing an optical film of the present invention. It is a schematic sectional drawing of the optical film of the 2nd Embodiment of this invention. It is a schematic sectional drawing of the optical film of the 3rd Embodiment of this invention. It is a schematic sectional drawing of the optical film of 4th Embodiment of this invention. It is a schematic sectional drawing of the optical film of the 5th Embodiment of this invention. It is a schematic sectional drawing of the optical film of the 6th Embodiment of this invention. It is a schematic sectional drawing of the optical film of 7th Embodiment of this invention. It is a schematic sectional drawing of the optical film of 8th Embodiment of this invention. It is a schematic sectional drawing of the optical film of the 9th Embodiment of this invention. It is a schematic sectional drawing of the optical film of the tenth embodiment of this invention. It is explanatory drawing which shows the state of observing whether or not an optical film is genuine using a viewer. FIG. 3 is a schematic cross-sectional view of an optical film according to an eleventh embodiment of the present invention in which a microlens array is provided on a liquid crystal layer. It is the schematic sectional drawing of the optical film of the twelfth embodiment of this invention which provided the lenticular lens array on the liquid crystal layer. 14 (a) to 14 (e) are views showing a process of transferring the liquid crystal layer of the optical film according to the 14th embodiment of the present invention to an article (transferred object). 15 (a) to 15 (h) and (h') are views showing a process of transferring the liquid crystal layer of the optical film according to the fifteenth embodiment of the present invention to an article (transferred object).

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and duplicate description will be omitted. Further, the dimensional ratios in the drawings are not limited to the ratios shown in the drawings.

First Embodiment The first embodiment of the optical film of the present invention will be described with reference to FIGS. 1 (a) to 1 (f). 1A to 1F are explanatory views for explaining a method for manufacturing an optical film according to the present embodiment.

First, as shown in FIG. 1A, the alignment film 20 is formed on the substrate 10. As shown in FIG. 1 (b), the surface of the alignment film 20 is subjected to a rubbing treatment using a rubbing roll 70 to impart an alignment ability to the alignment film 20.

Next, a surface treatment is performed to eliminate or weaken the alignment ability of a part of the region 22 of the alignment film 20. For example, as shown in FIG. 1 (c), a solvent is attached to the stamp (solvent coating means) 80, and the solvent is pressed against a part of the region (solvent coating portion) 22 on the alignment film 20 to which the alignment ability is imparted. As a result, the solvent is applied to the region 22 to eliminate the orientation ability of the region 22 (solvent coating step).

As shown in FIG. 1 (d), a liquid crystal composition containing a liquid crystal material is applied on the alignment film 20, the liquid crystal material is oriented by heating, and then the orientation is fixed to form the liquid crystal layer 30 (liquid crystal). Layer formation step). At this time, since the alignment ability of a part of the alignment film 20 has disappeared, the liquid crystal material is not regularly aligned in the region of the liquid crystal layer 30 located on the region 22, and the region 22 is different from the other regions. Since the orientation state of the liquid crystal material is different, the symbol 32 is formed on the liquid crystal layer 30. The symbol 32 corresponds to the symbol formed on the stamp 80.

As shown in FIG. 1 (e), the translucent protective film 50 is attached onto the liquid crystal layer 30 via the adhesive 40. As shown in FIG. 1 (f), the alignment film 20 and the substrate 10 are peeled off from the liquid crystal layer 30 to obtain an optical film 100 composed of the liquid crystal layer 30 / adhesive 40 / translucent protective film 50.

According to the above manufacturing method, the pattern 32 can be formed on the liquid crystal layer 30 very easily only by applying the solvent to the alignment film 20 by the solvent applying means such as the stamp 80. Further, after the liquid crystal layer 30 is formed, it is not necessary to apply an extra external force for forming a pattern such as pressing a heated hologram original plate, so that the liquid crystal layer 30 is not damaged. Therefore, by the above manufacturing method, it is possible to easily manufacture an optical film having a design property without damaging the liquid crystal layer. Hereinafter, each material and each process used in the above manufacturing method will be described in more detail.

The substrate 10 functions as a support for the alignment film 20 and the liquid crystal layer 30, and after the translucent protective film 50 is formed on the liquid crystal layer 30, the substrate 10 is peeled off together with the alignment film 20. Examples of the support substrate having such a function include polyimide, polyamideimide, polyamide, polyetherimide, polyetheretherketone, polyetherketone, polyketonesulfide, polyethersulphon, polysulphon, polyphenylenesulfide, polyphenylene oxide, and polyethylene terephthalate. , Polybutylene terephthalate, polyethylene naphthalate, polyacetal, polycarbonate, polyarylate, acrylic resin, epoxy resin, phenol resin, polyvinyl alcohol, cellulose-based plastics, polyethylene, polypropylene, poly (4-methyl-1-pentene), norbornene. Examples thereof include plastic films and sheets formed of chain-type or alicyclic-type polyolefins such as based resins.

Further, as the substrate 10, a plastic film or a sheet having a surface treatment such as a silicon treatment, or a resin coated with an acrylic resin, a methacrylic resin, an epoxy resin, or a paraffin wax can also be used. .. Further, as the substrate 10, a plastic film or sheet subjected to physical deformation treatment such as embossing, hydrophilization treatment, hydrophobic treatment or the like can also be used.

The thickness of the substrate 10 is usually 8 to 200 μm, preferably 15 to 150 μm, and more preferably 20 to 100 μm. When the thickness is thinner than 8 μm, the handleability at the time of manufacturing the optical film tends to be deteriorated. Further, when the thickness is thicker than 200 μm, the workability when the substrate 10 is peeled from the liquid crystal layer 30 together with the alignment film 20 tends to decrease.

The alignment film 20 is a layer having a function of aligning the liquid crystal material. The substrate 10 may also serve as the alignment film 20. Examples of the material constituting the alignment film 20 include polyvinyl alcohol, polyimide, polymethylmethacrylate, polystyrene, polycarbonate, polyethylene terephthalate and the like.

The alignment film 20 can be formed, for example, by applying a solution in which the constituent material is dissolved in a solvent onto the substrate 10, drying the film to form a film, and then rubbing the film to impart the alignment ability.

The solvent used for forming the alignment film 20 is appropriately selected depending on the material used, and examples thereof include acetone, cyclohexanone, toluene, methyl ethyl ketone, ethyl acetate, water, ethanol, and isopropyl alcohol. The solvent used when forming the alignment film 20 is preferably one that does not dissolve the substrate 10. Therefore, it is preferable to select materials having different solvents for dissolving each other as the constituent material of the alignment film 20 and the constituent material of the substrate 10.

Drying is performed by heat treatment under conditions according to the solvent used. The drying conditions may be appropriately adjusted depending on the type of solvent used, the film thickness, and the like, but are usually 20 to 60 seconds at 30 to 200 ° C.

The thickness of the alignment film 20 is usually 0.3 to 6 μm, preferably 0.6 to 2 μm, and more preferably 0.8 to 1.4 μm. When the thickness is thinner than 0.3 μm, it tends to be easily affected by defects such as fine scratches on the substrate 10, and when it is thicker than 3 μm, uneven drying tends to occur.

The alignment treatment of the alignment film 20 can be performed by a known method, but can be broadly classified into a rubbing treatment and a method other than the rubbing treatment. As a rubbing process, there is a method using a rubbing roll 70 as shown in FIG. 1 (b). As other alignment treatment methods, there are a method by stretching, a method by imprint, a method using an ultraviolet light alignment device, a soft X-ray alignment device, and the like.

The solvent used in the solvent coating step is not particularly limited as long as it can eliminate the alignment ability of the alignment film 20, but usually a solvent capable of dissolving the constituent material of the alignment film 20 is used. As the solvent used in the solvent coating step, the same solvent as that used for forming the alignment film 20 described above may be used, different solvents may be used, or a plurality of solvents may be used in combination. ..

The solvent application method is not particularly limited as long as the solvent can be applied to the alignment film 20, and in addition to the method using the stamp 80 as shown in FIG. 1 (c), spraying by spraying and printing with an inkjet printer. , Gravure printing, letterpress printing and the like.

The amount of the solvent applied may be any amount as long as it can eliminate the alignment ability of a part of the region 22 of the alignment film 20, and is appropriately adjusted.

After applying the solvent to a part of the region 22 of the alignment film 20, the solvent is dried. The drying conditions may be appropriately adjusted depending on the type of solvent used and the like, but are usually 10 to 30 seconds at room temperature.

The liquid crystal layer 30 can be formed by applying a liquid crystal composition containing a liquid crystal material on the alignment film 20, orienting the liquid crystal material by heating, and then fixing the orientation. Examples of the liquid crystal material include cholesteric liquid crystal, nematic liquid crystal, smectic liquid crystal and the like, and among them, cholesteric liquid crystal is preferable from the viewpoint of visibility of the design 32. Hereinafter, the case where the liquid crystal layer 30 is a cholesteric liquid crystal layer will be described in detail.

The cholesteric liquid crystal layer can be formed by using a liquid crystal composition containing a high molecular weight liquid crystal, a crosslinked low molecular weight liquid crystal, a mixture thereof, or the like as a main component.

The polymer liquid crystal is not particularly limited as long as the cholesteric orientation can be fixed, and any of a main chain type, a side chain type polymer liquid crystal and the like can be used. Specific examples thereof include main chain type liquid crystal polymers such as polyester, polyamide, polycarbonate and polyesterimide, and side chain type liquid crystal polymers such as polyacrylate, polymethacrylate, polymalonate and polysiloxane. Among these, liquid crystal polyester is preferable because it has good orientation in forming cholesteric orientation and is relatively easy to synthesize. As the constituent unit of the polymer, for example, an aromatic or aliphatic diol unit, an aromatic or aliphatic dicarboxylic acid unit, or an aromatic or aliphatic hydroxycarboxylic acid unit can be mentioned as a suitable example.

Examples of the crosslinked low-molecular-weight liquid crystal include those having a basic skeleton such as a biphenyl derivative having a functional group such as an acryloyl group, a vinyl group, or an epoxy group, a phenylbenzoate derivative, and a stillben derivative. Further, as the crosslinked low-molecular-weight liquid crystal, either one showing liotropic property or one showing thermotropic property can be used, but one showing thermotropic property is more preferable from the viewpoint of workability and the like.

As a method for immobilizing the cholesteric orientation, a known method can be used. For example, when a polymer liquid crystal is used as a liquid crystal material, a method of applying a polymer liquid crystal on the alignment film 20, expressing a cholesteric liquid crystal phase by heat treatment or the like, and quenching from that state to fix the cholesteric orientation. Can be used. When the crosslinked low molecular weight liquid crystal is used as the liquid crystal material, the crosslinked low molecular weight liquid crystal is coated on the alignment film 20 and then the cholesteric liquid crystal phase is expressed by heat treatment or the like, and light and heat are maintained while maintaining the state. Alternatively, a method of immobilizing the cholesteric orientation by cross-linking with an electron beam or the like can be appropriately adopted.

Further, in order to improve the heat resistance of the cholesteric liquid crystal layer, a cross-linking agent such as a bisazido compound or glycidyl methacrylate can be added to the liquid crystal composition in addition to the high molecular weight liquid crystal and the cross-linked low molecular weight liquid crystal. By adding these cross-linking agents, cross-linking can be performed in a state where the cholesteric liquid crystal phase is expressed. Further, various additives such as dichroic dyes, dyes and pigments can be appropriately added to the liquid crystal composition.

The liquid crystal layer 30 is usually composed of one liquid crystal layer such as the cholesteric liquid crystal layer described above, but may be configured by laminating a plurality of liquid crystal layers as needed.

The thickness of the liquid crystal layer 30 is usually 0.3 to 20 μm, preferably 0.5 to 10 μm, and more preferably 0.7 to 3 μm. If the thickness is less than 0.3 μm, the peculiar optical characteristic effect may not be effectively exhibited, and if it exceeds 20 μm, uneven drying tends to occur easily. When the liquid crystal layer 30 is a stack of a plurality of liquid crystal layers, it is desirable that the total thickness of all the liquid crystal layers falls within the above range.

As described above, in the liquid crystal layer 30, a portion where the alignment state of the liquid crystal material is different from the other regions is formed in the region 22 on the partial region 22 where the alignment ability of the alignment film 20 has disappeared. When the liquid crystal layer 30 is made of a cholesteric liquid crystal, the orientation structure of the liquid crystal molecules has regular twists so as to draw a spiral in the film thickness direction, and the directions of the liquid crystal molecules are aligned in the same plane. On the other hand, the orientations of the liquid crystal molecules on the region where the orientation ability has disappeared are not aligned in the same plane and become random, and the symbol 32 is formed due to the difference in the appearance of the reflected light.

A translucent protective film 50 is attached onto the liquid crystal layer 30 via an adhesive 40. The adhesive 40 may be such that the liquid crystal layer 30 and the translucent protective film 50 can be adhered to each other, and the pattern 32 formed on the liquid crystal layer 30 through the adhesive 40 is transparent to the extent that it can be visually recognized. However, the present invention is not particularly limited, and various conventionally known adhesives / adhesives can be used. Specifically, a hot melt type adhesive, a light or electron beam curing type reactive adhesive, or the like can be appropriately used. Among these, a reactive adhesive is preferable from the viewpoint of workability and the like.

The hot melt type adhesive is not particularly limited, but from the viewpoint of workability and the like, the hot melt working temperature is preferably 250 ° C. or lower, preferably 80 to 200 ° C., and more preferably 100 to 160 ° C. Specifically, as a hot melt type adhesive, for example, ethylene / vinyl acetate copolymer resin, polyester resin, polyurethane resin, polyamide resin, thermoplastic rubber, polyacrylic resin, polyvinyl alcohol resin, polyvinyl butyral. A hot melt adhesive using a polyvinyl acetal-based resin, a petroleum-based resin, a terpene-based resin, a rosin-based resin, or the like as a base resin can be used.

Reactive adhesives include light or electron beam polymerizable prepolymers and / or monomers, other monofunctional or polyfunctional monomers, various polymers, stabilizers, photopolymerization initiators, and sensitization, if necessary. It can be used by blending an agent or the like.

Specific examples of the prepolymer having light or electron beam polymerizable properties include polyester acrylate, polyester methacrylate, polyurethane acrylate, polyurethane methacrylate, epoxy acrylate, epoxy methacrylate, polyol acrylate, and polyol methacrylate. Examples of the monomer having light or electron beam polymerizable properties include monofunctional acrylate, monofunctional methacrylate, bifunctional acrylate, bifunctional methacrylate, trifunctional or higher polyfunctional acrylate, and polyfunctional methacrylate. Commercially available products can also be used for these, for example, Aronix (acrylic special monomer, oligomer; manufactured by Toagosei Co., Ltd.), Light Ester (manufactured by Kyoeisha Chemical Co., Ltd.), Viscort (Osaka Organic Chemical Industry Co., Ltd.). Manufactured by) and the like can also be used in the present invention.

Further, as the photopolymerization initiator, for example, benzophenone derivatives, acetophenone derivatives, benzoin derivatives, thioxanthones, Michler ketone, benzyl derivatives, triazine derivatives, acylphosphine oxides, azo compounds and the like can be used.

The viscosity of the light or electron beam curable reactive adhesive that can be used in the present invention is appropriately selected depending on the processing temperature of the adhesive and the like and cannot be unconditionally determined, but is usually 10 to 2000 mPa at 25 ° C. s, preferably 50 to 1000 mPa · s, more preferably 100 to 500 mPa · s. When the viscosity is lower than 10 mPa · s, it becomes difficult to obtain the desired thickness. Further, when it is higher than 2000 mPa · s, workability may be deteriorated, which is not desirable. When the viscosity is out of the above range, it is preferable to appropriately adjust the solvent and the monomer ratio to obtain the desired viscosity.

When a photocurable reactive adhesive is used, known curing means such as low pressure mercury lamp, high pressure mercury lamp, ultrahigh pressure mercury lamp, metal halide lamp, xenon lamp and the like can be used as the curing method of the adhesive. can. The exposure amount varies depending on the type of the reactive adhesive used and cannot be unequivocally determined, but is usually 50 to 2000 mJ / cm ² , preferably 100 to 1000 mJ / cm ² .

Further, when an electron beam curing type reactive adhesive is used, the method for curing the adhesive is appropriately selected depending on the penetrating power and the curing power of the electron beam, and cannot be unequivocally determined. It can be cured by irradiating it under the condition that the acceleration voltage is 50 to 1000 kV, preferably 100 to 500 kV.

The thickness of the adhesive 40 is not particularly limited, but is usually 0.5 to 50 μm, preferably 1 to 10 μm. Further, as a method for forming the adhesive 40, known methods such as a roll coating method, a die coating method, a bar coating method, a curtain coating method, an extrusion coating method, a gravure roll coating method, a spray coating method, and a spin coating method can be used. Can be used.

The translucent protective film 50 is not particularly limited as long as the design 32 formed on the liquid crystal layer 30 through the translucent protective film 50 is transparent to the extent that it can be visually recognized. For example, triacetyl cellulose (TAC). ), Polymethylmethacrylate, polystyrene, polycarbonate, polyether sulfone, polyphenylene sulfide, amorphous polyolefin, polyethylene terephthalate, polyethylene naphthalate, cycloolefin polymer (COP), polyvinyl alcohol and the like. The translucent protective film 50 may contain an ultraviolet absorber. Further, the translucent protective film 50 may be a hard coat layer. When used as a hard coat layer, beads or metal powder (glitter) may be contained in order to improve the design. Further, in order to add the purpose of antireflection, an antireflection film may be used as the protective film, or an antireflection layer may be formed on the protective film.

The thickness of the translucent protective film 50 is not particularly limited, but is usually 8 to 200 μm, preferably 20 to 100 μm.

The method of peeling the alignment film 20 and the substrate 10 from the liquid crystal layer 30 is not particularly limited. A method of mechanically peeling using the method, a method of mechanically peeling after immersing in a poor solvent for all structural materials, a method of applying ultrasonic waves in a poor solvent to peel off, an alignment film 20 or a substrate 10 and a liquid crystal layer 30. It can be carried out by a method of peeling by giving a temperature change by utilizing the difference in the thermal expansion coefficient of.

The optical film of the present invention in which the liquid crystal material in a part of the liquid crystal layer and the liquid crystal material in another region are the same, and the liquid crystal material in the part and the liquid crystal material in the other region have different orientation states. Although the manufacturing method of the above has been described, the optical film of the present invention can also be manufactured by another manufacturing method. For example, as shown in FIG. 1A, an alignment film 20 is formed on the substrate 10, and then a mask having an opening in a predetermined region is attached to the alignment film in order to impart the alignment ability only to a predetermined region. Install on top. Next, in the same manner as in the above embodiment, a rubbing treatment is performed from above the mask using a rubbing roll. By doing so, the alignment ability can be imparted only to the alignment film in the predetermined region exposed to the opening of the mask. Next, a liquid crystal composition containing a liquid crystal material can be applied onto the alignment film in the same manner as in the above embodiment, the liquid crystal material can be oriented by heating, and then the orientation can be fixed to form a liquid crystal layer. At this time, since the region other than the predetermined region of the alignment film does not have the alignment ability, the liquid crystal material is not regularly aligned in the region of the liquid crystal layer located on the region, and the predetermined region is the orientation of the liquid crystal material. Since the states are different, a pattern is formed on the liquid crystal layer. Finally, a translucent protective film is attached onto the liquid crystal layer via an adhesive in the same manner as in the above embodiment, and the alignment film and the substrate are peeled off from the liquid crystal layer to remove the liquid crystal layer / adhesive / translucency. An optical film made of a protective film can be obtained.

In addition, the surface treatment of the alignment film can also be performed by using a method such as direct drawing with _{CO 2 laser light, excimer UV irradiation using a mask, or electron beam (EB) drawing.} Regions with different orientations can be formed.

The optical film 100 composed of the liquid crystal layer 30, the adhesive 40, and the translucent protective film 50 can be used for anti-counterfeiting, decoration, and the like. The optical film 100 can be used by applying an adhesive or the like on the side of the liquid crystal layer 30 and attaching it to a label, a tag, a cosmetic box, a packing material, a packaging material, or the like. These may have a pattern. Further, as described in detail in the embodiment described later, the optical film 100 is provided with an adhesive layer such as a hot melt agent or an electromagnetic wave curable resin applied to the liquid crystal layer 30 side, and then the adhesive layer side is in contact with an article such as a label. Then, it can be hot-stamped or irradiated with electromagnetic waves from the side of the translucent protective film 50 to be adhered to an article such as a label. Further, by using a member having low solvent resistance such as a COP film for the translucent protective film 50, it is possible to prevent reuse by peeling the film with a solvent. A water-soluble film or the like can be used for the same purpose. Further, the adhesive 40 and the translucent protective film 50 can be peeled off and used as a transfer foil.

It should be noted that different members (hereinafter referred to as back surface members) can be formed or adhered to the outermost surface of the optical film 100 on the liquid crystal layer 30 side, that is, the back side of the liquid crystal layer 30 for various purposes. Specific examples of the back surface member will be illustrated below.

(1) Colored back surface member The color of the "back surface member" (label, tag, etc.) attached to the side of the liquid crystal layer 30 or the design provided on them is black (green), white (red), blue (blue), etc. By changing to the color of, the visual color is also different. For example, it is assumed that the liquid crystal layer 30 is made of a liquid crystal material that reflects green right-handed circularly polarized light. In this case, when the color of the back surface member is black, the color when viewed from the front surface side of the liquid crystal layer (strictly speaking, the color visually observed by peeling off the adhesive and the translucent protective film) is green, but the back surface. When the member is white, it looks like a complementary color of red. Also, when the back surface member is blue, it looks blue. Therefore, by changing the color of the back surface member, it is possible to express the RGB color even though it is a monochromatic optical film. When an optical film having such a back surface member is observed through a left circular polarizing filter of a viewer described later, the design of the liquid crystal layer disappears and only the design and color of the back surface member can be seen.

(2) Back surface member having an inclined uneven structure The back surface member may have an uneven structure having an inclined surface. The concavo-convex structure has a size in the nano to millimeter unit, and can be formed by a known method such as a nanoimprint method or embossing. When the incident light has an incident angle θ, the light having a wavelength λ satisfying the reflection condition of Bragg of p · cos θ = λ / n (p is the thickness of the back surface member, n is the refractive index of the back surface member). It is selectively reflected by diffraction. Therefore, colors with shorter wavelengths are observed than when observing at an angle. Light of wavelength λ diffracted in the front direction due to the inclined unevenness on the back surface passes through the spiral structure of the liquid crystal, so that the same effect as when observing at an angle can be obtained even when observing from the front, and it is multicolored. Can be expressed. By adjusting the tilt angle, it is possible to colorize the product, which has the effect of improving the design.

(3) Back surface member as a retardation member A liquid crystal layer (nematic liquid crystal) or a retardation film formed by an uneven structure may be laminated as a back surface member, and a reflection layer may be provided on the back surface member. By providing the reflective layer, the transmitted reverse-twisted circularly polarized light is returned, so that the pattern of the cholesteric layer is not erased by the circular polarizing plate (and the linear polarizing plate). On the other hand, although the retardation film is transparent to the naked eye, it can be colored and recognized by viewing it through a linear polarizing plate. Further, when the retardation film is arranged under the cholesteric liquid crystal, the unaligned portion of the cholesteric liquid crystal can recognize the retardation film portion without the polarizing plate.

(4) Back surface member as a mirror surface member A back surface member composed of a transparent member (glass, film) / reflective portion may be used. The reflective portion may be the entire surface or may be partially formed. If there is a reflective part, the pattern will not disappear with a viewer using a circular polarizing filter. You may write a pattern or letters on the mount brought to the back with a highly reflective material such as aluminum foil. Alternatively, a pattern may be written on the aluminum foil with, for example, black ink. If you use the right circular polarizing filter of the viewer, only the characters written on the aluminum foil will disappear. When the transparent member is thick, when observed at an angle, the reflected image on the surface of the transparent member and the reflected image on the reflective part are misaligned, and the pattern of the cholesteric liquid crystal layer appears to stand out visually (pseudo). 3D pattern). This improves the design. The various back surface members as described above can be formed from materials such as PET, COP, TAC and the like.

The optical film of the present invention has an extremely wide range of uses, and can be used as various optical elements, optoelectronic elements, decorative members, anti-counterfeiting elements, and the like. In particular, it can be used as a new film, seal, label or the like having the respective effects of a diffraction element and a cholesteric liquid crystal. For example, it can be attached to or embedded in a supporting base material such as a car driver's license, an ID card, a passport, a credit card, a prepaid card, various cash vouchers, a gift card, a card board for securities, and a mount. Also, as a sticker, it can be attached to products such as batteries, cameras, calculators, and watches. It can be used as a label, for example, as a textile label to be sewn on clothing such as neckties and shirts.

In particular, when used as an anti-counterfeiting element, a viewer 120 as shown in FIG. 11 is usually used in order to confirm that the optical film or the transferred product transferred from the optical film is genuine. A right-handed circularly polarized light filter 120a that allows only right-handed circularly polarized light to pass through and a left-handed circularly polarized light filter 120b that allows only left-handed circularly polarized light to pass through are attached to the two openings of the viewer 120. Here, it is assumed that the liquid crystal layer of the optical film 100 of the embodiment mounted on the support 130 such as a card is made of a liquid crystal material that reflects only right-handed circularly polarized light. When the optical film 100 is irradiated with natural light having a polarizing component in a random direction, only right-handed circularly polarized light is reflected from the liquid crystal layer of the optical film 100, and the reflected light passes through the right-handed circularly polarized light filter 120a of the viewer 120. Therefore, the design and design attached to the liquid crystal layer can be seen through the right circular polarizing filter 120a. On the other hand, since the right circularly polarized light reflected from the liquid crystal layer cannot pass through the left circularly polarized light filter 120b, the design or design attached to the liquid crystal layer cannot be seen. For the purpose of discrimination only, only the circularly polarized light filter in the rotation direction in which the design cannot be seen may be used.

Hereinafter, examples of the optical film of the first embodiment will be described more specifically, but the present invention is not limited to the following examples.

(Example 1)
A PET (polyethylene terephthalate) film was used as the substrate. The PET film has an orientation ability and also serves as an alignment film. The stamp with toluene attached to the PET film was pressed at a pressure of 10 kPa for 0.2 seconds, and then dried at room temperature for 15 seconds.

Nematic liquid crystal (manufactured by PALIOCOLOR LC242 BASF Co., Ltd.) 19.0% by weight, chiral agent (manufactured by PALIOCOLOR LC756 BASF Co., Ltd.) 1.0% by weight, acylphosphine oxide-based photopolymerization initiator (IRGACURE TPO BASF Co., Ltd.) Manufactured by) A solution consisting of 0.8% by weight and 79.2% by mass of cyclohexanone is applied onto a PET film so that the thickness after drying is 1.6 μm, and heated in a drying oven at 55 ° C. for 15 minutes to dry. I let you. Next, the liquid crystal was oriented by leaving it in a heat treatment furnace heated to 100 ° C. for 10 minutes and in a heat treatment furnace heated to 80 ° C. for 10 minutes, and irradiated with light by an LED-UV lamp to fix the orientation, and the cholesteric liquid crystal layer was formed. Formed.

A PC (polycarbonate) film is attached onto the liquid crystal layer via an ultraviolet curable adhesive (manufactured by Toagosei Co., Ltd., trade name: Aronix UV-3630), and light is irradiated with a high-pressure mercury lamp to apply the adhesive. It was cured. Then, the PET film was peeled off from the liquid crystal layer to obtain an optical film composed of a liquid crystal layer / adhesive / PC film.

(Example 2)
A solution consisting of 4% by mass of PVA (polyvinyl alcohol), 76.8% by mass of pure water, and 19.2% by mass of IPA (isopropyl alcohol) was placed on a PEN (polyvinyl alcohol) film in a thickness of 1.2 μm after drying. The PVA film was formed by applying the mixture so as to be the same as above, and drying the film in a drying oven at a temperature of 40 ° C. to 130 ° C. for 36 seconds. A low-density polyethylene film having a thickness of 30 μm cut out in a character shape was attached to the PVA film, and a rubbing treatment was performed using a rubbing roll to which a rubbing cloth was attached to form an alignment film.

A cholesteric liquid crystal layer was formed on the alignment film in the same manner as in Example 1. Further, the TAC film was attached on the liquid crystal layer in the same manner as in Example 1 except that the TAC (triacetyl cellulose) film was used instead of the PC film. Then, the alignment film and the PEN film were peeled off from the liquid crystal layer to obtain an optical film composed of a liquid crystal layer / adhesive / TAC film.

(Example 3)
An alignment film was formed in the same manner as in Example 2 except that the entire PVA film was subjected to a rubbing treatment without using a polyethylene film cut out in a character shape.

The solvent was applied to the alignment film by pressing a stamp with a mixed solvent of water and ethanol (water: ethanol = 2: 1 (mass ratio)) on the alignment film at a pressure of 1 kPa for 0.2 seconds. .. Then, the part coated with the solvent was dried at room temperature for 15 seconds.

A cholesteric liquid crystal layer was formed on the alignment film in the same manner as in Example 1. Further, in the same manner as in Example 2, a TAC film was attached on the liquid crystal layer. Then, the alignment film and the PEN film were peeled off from the liquid crystal layer to obtain an optical film composed of a liquid crystal layer / adhesive / TAC film.

It was confirmed that the stamp pattern was formed on the liquid crystal layer of the optical film obtained in Examples 1 to 3. The pattern formed on the optical film was clear and easily visible. In addition, no damage to the liquid crystal layer was confirmed.

The optical film 100 of the first embodiment is composed of a liquid crystal layer 30 / an adhesive 40 / a translucent protective film 50, and a portion of the liquid crystal layer 30 whose orientation state of the liquid crystal material is different from that of other regions is formed thereby. Formed a design that brings about design. However, the optical film of the present invention is not limited to the structure and usage of the optical film 100 of the first embodiment, and may take various forms as described below.

2nd Embodiment In the 1st embodiment, the design is formed by the orientation state of the liquid crystal material of the liquid crystal layer, but in order to further enhance the design of the design, the lower surface of the liquid crystal layer 30 is shown as in the optical film 102 shown in FIG. The uneven pattern 60 that produces a hologram may be provided on the surface. The uneven pattern 60 is provided so as to cover both the portion 30a in which the orientation of the liquid crystal material of the liquid crystal layer 30 is lost and the portion 30b in which the orientation is maintained. The light that has passed through the liquid crystal layer 30 and reached the uneven pattern 60 generates diffracted light according to the pitch and incident angle of the uneven pattern 60. Since this diffracted light passes through the liquid crystal layer 30, it has optical rotation peculiar to the liquid crystal layer. That is, when the liquid crystal layer is a cholesteric liquid crystal that reflects right-handed circularly polarized light, the diffracted light is also right-handed circularly polarized light. Therefore, when the optical film 102 is observed with the right-handed circularly polarizing filter 120a as shown in FIG. 11, a hologram having a color corresponding to a diffraction pattern such as rainbow color can be observed. Further, the pattern formed by the portions 30a and 30b can also be observed. On the other hand, even if the optical film 102 is observed with the left circular polarizing filter 120b, the field becomes dark and neither the diffracted light nor the pattern can be observed.

With such a configuration, not only the presence or absence of orientation of the liquid crystal layer 30 but also the designability can be enhanced by the diffracted light such as a hologram generated from the uneven pattern 60. The uneven pattern can be formed by any method such as embossing or nanoimprint. An adhesive layer such as an adhesive sticker, a release paper, a protective film, a base material, and the like may be further provided on the lower surface of the uneven pattern 60.

3rd Embodiment In the 2nd embodiment, the uneven pattern 60 is formed on the lower surface of the liquid crystal layer 30, but the reflective layer 72 having the uneven pattern 60 on the lower surface is provided on the liquid crystal layer 30 as in the optical film 103 shown in FIG. You may. The reflective layer 72 may be made of a cholesteric liquid crystal material that reflects right circularly polarized light. When the optical film 103 is observed with the right circular polarizing filter as in the second embodiment, in addition to the diffracted light having a color corresponding to the diffraction pattern such as iridescent color, the pattern formed by the portions 30a and 30b is also observed. However, even if the optical film 103 is observed with the left circular polarizing filter, the field of view becomes dark and neither the diffracted light nor the pattern can be observed. With such a configuration, not only the presence or absence of orientation of the liquid crystal layer 30 but also the designability can be enhanced by the diffracted light such as a hologram generated from the uneven pattern 60. A protective film or a base material may be further provided on the lower surface of the reflective layer 72.

Fourth Embodiment In the first embodiment, a single liquid crystal layer is provided, but a second liquid crystal layer 32 may be provided on the lower surface of the liquid crystal layer 30 as in the optical film 104 shown in FIG. In this case, the portion 32a in which the orientation of the liquid crystal material of the second liquid crystal layer 32 has disappeared and the portion 32b in which the orientation is maintained maintain the orientation with the portion 30a in which the orientation of the liquid crystal material in the liquid crystal layer 30 has disappeared. The position in the layer may be shifted with respect to the portion 30b. Further, the liquid crystal layer 30 and the second liquid crystal layer 32 may have different colors of reflected light by making the pitch and the refractive index of the layered structure of the liquid crystal material different. For example, the liquid crystal layer 30 is made of a liquid crystal material that reflects red by specular reflection, and the second liquid crystal layer 32 reflects blue by specular reflection. In this case, when the optical film 104 is observed from the front with the naked eye, it looks purple. On the other hand, when the optical film 104 is observed with the right circular polarizing filter made of the same liquid crystal material as the liquid crystal layer 30, red appears, and when the optical film is observed with the right circular polarizing filter made of the same liquid crystal material as the liquid crystal layer 32, it looks blue. .. By doing so, the design can be increased.

Instead of making the reflected colors of the liquid crystal layer 30 and the second liquid crystal layer 32 different as described above, the rotational properties of the circularly polarized light reflected by the liquid crystal layer 30 and the second liquid crystal layer 32 may be reversed. For example, each liquid crystal material is adjusted so that the liquid crystal layer 30 reflects the right circularly polarized light and the second liquid crystal layer 32 reflects the left circularly polarized light. Then, when the optical film 104 is observed with the right circular polarizing filter, only the patterns (30a, 30b) formed on the liquid crystal layer 30 with or without orientation appear to stand out, and when the optical film 104 is observed with the left circular polarizing filter, the liquid crystal is displayed. Only the patterns (32a, 32b) formed on the layer 32 with or without orientation appear to stand out. In this case, if one combination or a superposed pattern is generated by the pattern of the liquid crystal layer 30 and the pattern of the second liquid crystal layer 32, the visual design is improved.

The liquid crystal layer is not limited to two layers, and may be a plurality of three or more layers. Further, a plurality of liquid crystal layers as in the present embodiment may be introduced into the optical film having the uneven pattern of the second or third embodiment.

Fifth Embodiment In the first embodiment, the design is formed by the orientation state of the liquid crystal material of the liquid crystal layer, but in order to further enhance the design of the design, the lower surface of the liquid crystal layer 30 is shown as in the optical film 105 shown in FIG. The print layer 82 may be provided on the surface. The print layer 82 can be provided with a logo or design of a manufacturer or a dealer of the article to which the optical film 105 is attached. Further, a photograph may be attached to the print layer 82 in place of or in addition to the logo or design. The print layer 82 may be made of a material that is not polarized or dizzy so that it can be visually recognized, and if the liquid crystal layer 30 of the optical film 105 is formed of a liquid crystal material that reflects right-handed circularly polarized light. When the optical film 105 is observed with the left circular polarizing filter, the logo and design of the printing layer 82 can be observed, but the patterns (30a, 30b) formed on the liquid crystal layer 30 with or without orientation cannot be seen, and the optical film with the right circular polarizing filter cannot be seen. When observing 105, patterns (30a, 30b) formed on the liquid crystal layer 30 with or without orientation can be seen, but the logo and design of the print layer 82 are hidden behind the liquid crystal layer 30 (by reflected light from the liquid crystal layer 30). Become invisible.

The print layer 82 may be configured by using thermochromic ink or photochromic ink. By doing so, the color of the print layer 82 can be changed by heating or light irradiation, and the distinctiveness can be improved.

By providing such a print layer 82 on the bottom layer of the optical film of the first to fourth embodiments, the decorativeness can be further increased. For example, a print layer having a pattern can be provided on the lower surface of the uneven pattern of the optical film of the second or third embodiment, and in that case, the pattern and the uneven pattern of the hologram may be formed so as to match. By doing so, when observing through the viewer, the design and the hologram pattern appear to overlap, and the design is improved.

6th Embodiment Instead of the printing layer 80 provided in the 5th embodiment, the light absorption layer 90 may be provided on the lowermost layer as in the optical film 106 shown in FIG. By providing the light absorption layer 90, it is possible to prevent the reflected light from the article below the liquid crystal layer 30 and make the pattern due to the orientation state of the liquid crystal material of the liquid crystal layer more visible and vivid. The light absorption layer 90 can be, for example, a black print layer made of a pigment or dye. The light absorption layer 90 may cover the entire surface of the liquid crystal layer 30, or may be provided on the lower surface of the liquid crystal layer 30 so as to partially cover the liquid crystal layer 30. By partially providing the light absorption layer 90 on the lower surface of the liquid crystal layer 30 in a specific pattern, the design by the light absorption layer 30 is generated. As the light absorption layer 90, not only a material that absorbs visible light but also a material that absorbs ultraviolet rays may be used as the ultraviolet absorption layer. The light absorption layer 90 may be provided on the bottom layer of the optical film of the first to fifth embodiments.

Seventh Embodiment The optical film 100 of the first embodiment has a laminated structure of a liquid crystal layer 30 / an adhesive 40 / a protective film 50, but like the optical film 107 shown in FIG. 7, it is combined with the protective film 50. A light-transmitting decorative layer 92 may be provided between the liquid crystal layers 30. The decorative layer 92 may be a colored light-transmitting layer or a film having a flat logo or design. The decorative layer 92 has a thickness such that when observed with the viewer 120 as shown in FIG. 11, the circularly polarized light reflected from the liquid crystal layer 30 is transmitted and the pattern due to the orientation state of the liquid crystal material of the liquid crystal layer can be recognized. It is desirable to maintain the transmittance. By doing so, the design of the optical film 100 can be enhanced. The decorative layer 92 can be formed from any material such as a light-transmitting polymer and is fixed between the liquid crystal layer 30 and the protective film 50 via an adhesive 40.

Instead of providing the decorative layer 92, the protective film 50 of the optical film 100 of the first embodiment may be directly designed or colored. In this case, the surface of the protective film may be printed, or the protective film 50 may be formed from another material by adding a pigment or a powder that produces gloss.

Eighth Embodiment In the second embodiment, the uneven pattern 60 is provided on the lower surface of the liquid crystal layer 30, but the optical film 108 of this embodiment has a partial region, for example, a left half region as shown in FIG. The uneven pattern 60 is provided only on the lower surface of the liquid crystal layer 30 of 108a, and the region 30a having a different orientation state is provided only on the liquid crystal layer 30 of the right half region 108b. By doing so, when the liquid crystal layer 30 is made of a liquid crystal material that reflects right circularly polarized light, when the optical film 108 is observed through the right circularly polarized light filter 120a as shown in FIG. 11, the concavo-convex pattern 60 starts from the region 108a. A hologram pattern due to the generated diffracted light can be observed, and a pattern generated by the regions 30a having different orientation states can be visually recognized from the region 108b. Therefore, when both these patterns and hologram patterns can be observed from each region, the design can be further enhanced.

9th Embodiment In the 5th embodiment, the printing layer is provided on the lower surface of the liquid crystal layer, but the optical film 109 shown in FIG. 9 replaces the liquid crystal layer 30 in a part of the region, for example, the left half region 109a. A print layer 84 having a print pattern 84a is provided on the surface, and a liquid crystal layer 30 is provided only on the right half region 109b. Then, a region 30a having a different orientation state is provided only in a part of the liquid crystal layer 30. The liquid crystal layer 30 is made of a liquid crystal material that reflects right-handed circularly polarized light. When the optical film 109 is visually viewed from the front, the print pattern 84a of the print layer 84 can be seen from the region 109a, and the pattern formed by the region 30a in which the orientation state of the liquid crystal is different can be seen from the region 109b. Further, when the optical film 109 is observed through the right circular polarizing filter, a printed pattern can be seen from the region 109a, and a pattern formed by the region 30a having a different orientation state can be seen from the region 109b, as in the case of visual inspection. When the optical film 109 is observed through the left circular polarizing filter, a printed pattern can be seen from the region 109a, and the region 109b becomes a dark field. The print layer 30 and the liquid crystal layer 30 may have the same color, and by doing so, the difference between the visual observation through the right circular polarizing filter and the observation through the left circular polarizing filter becomes clearer.

10th Embodiment FIG. 10 shows a modification of the second embodiment. In the second embodiment, the uneven pattern 60 is formed on the lower surface of the liquid crystal layer 30, but in the optical film 110 shown in FIG. 10, the uneven pattern 60 that forms a hologram pattern between the liquid crystal layer 30 and the protective film 50 is provided. An intermediate layer 94 having the intermediate layer 94 is provided. The uneven pattern 60 is provided on a surface where the intermediate layer 94 faces the liquid crystal layer 30. The intermediate layer 94 can be made of, for example, a cholesteric liquid crystal material that reflects the same right-handed circularly polarized light as the liquid crystal layer 30. In this case, when the optical film 110 is visually observed from the front, the hologram pattern due to the uneven pattern 60 can be observed. On the other hand, due to the color shift of the liquid crystal layer 30 observed from an oblique direction, the pattern due to the orientation state of the liquid crystal material appears to be colored.

Eleventh Embodiment FIG. 12 shows an optical film 112 provided with a microlens array 150 in place of the protective film on the liquid crystal layer 30 of the optical film of the first embodiment. The microlens array 150 is formed by arranging a plurality of microlenses 150a on the liquid crystal layer 30 like a grid, and each lens has a diameter of, for example, several μm. The symbols formed by the regions 30a and 30b in which the orientation states of the liquid crystal layers 30 are different are those formed by forming a predetermined stereoscopic image through the microlens array 150 in advance. By observing the pattern thus formed through the microlens array 150, it can be seen as a three-dimensional stereoscopic image. The microlens array 150 is formed by using acrylic or the like so that birefringence does not occur, so that the image that can be seen only through the right circular polarizing filter through the viewer viewer looks three-dimensional, so that the visible image is given a design. Can be done.

12th Embodiment FIG. 13 shows an optical film 114 provided with a lenticular lens array 160 in place of the protective film on the liquid crystal layer 30 of the optical film 100 of the first embodiment. The lenticular lens array 160 is formed by arranging a plurality of semi-cylindrical lenticular lenses 160a on the liquid crystal layer 30 in a predetermined direction, and each lenticular lens has a width of, for example, several μm to several mm. The region of the liquid crystal layer 30 below each lenticular lens 160a is divided into three regions, for example, regions α, β, γ as shown in FIG. 13, and the liquid crystal layer 30 is provided in each of the regions α, β, γ. A symbol as a unit is formed by the configured regions 30a and 30b having different orientation states. One symbol is constructed by combining the aggregates of the symbols in the region α. The same applies to the symbols of the region β and the region γ. By doing so, when the lenticular lens array 160 is viewed from a specific direction (a specific angle with respect to the optical axis of the lenticular lens array 160), only the pattern in the region α can be observed. Further, when the lens array 160 is viewed from the front, only the pattern due to the region β can be observed. Further, when the lenticular lens array 160 is viewed from the direction opposite to the normal when the symbol in the region α is seen, the symbol in the region γ can be observed. That is, different patterns can be observed depending on the viewing direction. Therefore, by forming the lenticular lens array 160 so that birefringence does not occur, the image seen through the right circular polarizing filter through the viewer looks different depending on the viewing direction, so that the design of the design can be increased. The symbol recorded in the regions α, β, and γ may be a symbol such as a moving image or a symbol that looks three-dimensional, which is continuously connected depending on the viewing direction.

13th Embodiment A pattern may be formed on the upper layer or the lower layer of the translucent protective film 50 of the optical film 100 of the 1st embodiment by using IR ink, UV ink or the like. The pattern formed by these inks absorbs infrared rays or ultraviolet rays to develop a color, so that it cannot be visually observed, but it can be detected by using infrared rays or ultraviolet rays. By doing so, it is possible to detect the pattern of the liquid crystal layer with visible light by the viewer, and further detect the pattern by IR ink or UV ink by irradiating infrared rays or ultraviolet rays, so that the detection method can be applied in two steps. can. In this case, it is desirable that the design with IR ink or UV ink is formed from a material that transmits visible light. The form of forming a pattern using such IR ink, UV ink, or the like may be used not only in the first embodiment but also in combination with the optical film of any of the above embodiments.

14th Embodiment The optical film of the present invention is suitable for various uses as described above, but the act of peeling off the optical film once attached to an article such as a product and attaching it to another article, that is, , It is desirable to be able to prevent reuse. 14 (a) to 14 (e) show an example of a process of manufacturing an optical film capable of preventing such reuse and transferring the liquid crystal layer of the optical film to an article (transferred object).

The laminate shown in FIG. 14 (a) is a laminate obtained in the liquid crystal forming step (FIG. 1 (d)) of the process shown in FIG. 1, and the orientation of the liquid crystal layer is fixed by the alignment film on the substrate. Moreover, a pattern is formed. In the first embodiment, the translucent protective film is attached to the laminate via an adhesive, but in this example, the separator is attached via the glue layer and the laminate is as shown in FIG. 14 (b). Get the body. Next, the alignment film of this laminated body is peeled off together with the substrate and removed to obtain a laminated body composed of a liquid crystal layer / glue layer / separator as shown in FIG. 14 (c). Since this laminate can be attached to various useful articles by peeling off the separator later, it becomes a product form as a transfer sealing material. In addition, in order to protect the surface of the exposed liquid crystal layer of the laminated body shown in FIG. 14 (c), a protective film may be provided on the surface of the liquid crystal layer (opposite side of the glue layer). Next, the separator is peeled off from this laminated body as shown in FIG. 14 (d) and attached to the article. In this way, as shown in FIG. 14 (e), the liquid crystal layer could be transferred to the article via the separator. When the protective film is provided on the surface of the liquid crystal layer of the laminated body as shown in FIG. 14 (c), the laminated body can be attached to the article and then peeled off. Here, since the liquid crystal layer 30 can be manufactured as an extremely thin film such as 0.3 to 9.0 μm, particularly 0.3 to 6.0 μm as described above, the liquid crystal layer is more than the peeling force of the glue layer. The breaking strength is low, the glue layer is elastically deformed, and the liquid crystal layer is broken. Therefore, the optical film having a liquid crystal layer cannot be reused.

In the processes shown in FIGS. 14 (a) to 14 (e), as the separator, an olefin resin such as polyethylene, polypropylene, 4-methylpentene-1 resin, polyamide, polyimide, polyamideimide, polyetherimide, polyetherketone, etc. Polyether ether ketone, polyethersulfone, polyketone sulfide, polysulfone, polystyrene, polyphenylene sulfide, polyphenylene oxide, polyethylene terephthalate (PET), polybutylene terephthalate, polyarylate, polyacetal, uniaxially stretched polyester, polycarbonate, polyvinyl alcohol, polymethylmethacrylate, Any material film such as polyarylate, amorphous polyolefin, norbornene resin, uniaxially stretched polypropylene film (OPP) triacetyl cellulose (TAC), epoxy resin and the like can be used. As the triacetyl cellulose (TAC), saponified triacetyl cellulose (TAC) as disclosed in JP-A-2004-138697 can also be used.

The adhesive may be any adhesive or adhesive as long as it adheres to the liquid crystal layer and the separator can be peeled off, and may be a material that requires post-treatment such as hot stamping or curing by UV irradiation. No. As the separator, a transfer tape with a double-sided separator to which the glue has already adhered, for example, 467MP, 9458, 9626 manufactured by 3M, etc. may be used.

Fifteenth Embodiment FIGS. 15 (a) to (h) and (h') show modified examples of the process described in the fourteenth embodiment. The laminate shown in FIG. 15 (a) is a laminate obtained in the liquid crystal forming step (FIG. 1 (d)) of the process shown in FIG. 1, and the orientation of the liquid crystal layer is fixed by the alignment film on the substrate. Moreover, a pattern is formed. As shown in FIG. 15B, an adhesive layer is formed on the surface of the liquid crystal layer of such a laminated body. As the adhesive layer, a hot melt type adhesive or a light or electron beam curable type reactive adhesive is suitable. As described later, the adhesive layer can be selected to be left on the liquid crystal layer or not left after the laminate is finally attached to the article. Next, the separator 1 is attached onto the adhesive layer as shown in FIG. 15 (c). As the separator 1, the same material as the separator used in the 14th embodiment can be used. Next, the light distribution layer of this laminated body is peeled off together with the substrate and removed to obtain a laminated body composed of a liquid crystal layer / adhesive layer / separator 1 as shown in FIG. 15 (d). As shown in FIG. 15 (e), the separator 2 is attached to the exposed liquid crystal layer of the laminated body via the glue layer, so that the laminate is composed of the separator 2 / glue layer / liquid crystal layer / adhesive layer / separator 1. Get the body.

Since this laminate can be attached to various useful articles by peeling off the separator 1 and the separator 2 later, it can be made into a product form as a sealing material. When the laminate is attached to the article, the separator 2 is peeled off as shown in FIG. 15 (g) and attached to the article via the glue of the laminate. Finally, the separator 1 is peeled off leaving the adhesive, and the form is as shown in FIG. 15 (h). By leaving the adhesive on the outermost surface, it can function as a protective film for the liquid crystal layer to impart heat resistance and light resistance, and it can be re-peeled after being attached to an article by utilizing the thickness and strength of the adhesive layer. It may be possible.

Instead of peeling the separator 1 from the adhesive layer, as shown in FIG. 15 (h'), the separator 1 can be peeled together with the adhesive so that only the liquid crystal layer remains on the article via the glue layer. .. In this case, since the liquid crystal layer 30 can be made into an extremely thin film of about 1 to 3 μm as described above, such a thin film cannot be easily peeled off from the article, and the liquid crystal layer 30 is forced to peel off. If so, the liquid crystal layer itself will be broken. Therefore, the optical film cannot be reused. Whether the adhesive layer is left (FIG. 15 (h)) or not (FIG. 15 (h')) is the magnitude relationship between the adhesive force of the adhesive layer to the separator 1 and the adhesive force of the adhesive layer to the liquid crystal layer. It can be determined by selecting the material of the adhesive layer in consideration of.

The separator 1, separator 2, adhesive, and adhesive used in the optical films of the 14th and 15th embodiments are re-peeled in JP-A-2003-121643, JP-A-2004-117522, and JP-A-2004-138697. Various substances are disclosed as a sex substrate or a separate film, and an adhesive or a pressure-sensitive adhesive for adhering them to a liquid crystal substance, and they can also be used.

Although FIGS. 14 (a) to 14 (e) and FIGS. 15 (a) to (h) and (h') show an example in which the alignment film is used as in the first embodiment, the substrate itself is A substrate having orientation may be used. In this case, the alignment film can be omitted.

Although the optical film of the present invention has been described above in various embodiments, the characteristic structure and arrangement described in each embodiment can be incorporated into another embodiment.

For example, the intermediate layer 94 described in the tenth embodiment may be provided so as to cover the upper surfaces of the print layer 84 and the liquid crystal layer 30 of the ninth embodiment. In this case, it is not necessary to provide the intermediate layer 94 with a region having a different orientation state only partially, and to provide the liquid crystal layer 30 adjacent to the print layer 84 with a region 30a having a different orientation state. When the liquid crystal layer 30 is not provided with regions 30a having different orientation states, the liquid crystal layer 30 does not need to be manufactured by the above-mentioned method, and a liquid crystal ink in which small pieces of cholesteric liquid crystal are dispersed in an ink vehicle is used. May be configured.

Further, the print layer 82 described in the fifth embodiment or the light absorption layer 90 described in the sixth embodiment may be provided on the lowermost surface of the optical film of another embodiment.

In the description of the second embodiment, it has been described that an adhesive layer such as an adhesive sticker, a release paper, a protective film, a base material, and the like can be further provided on the lowermost surface (concave and convex pattern 60) of the optical film 102, but other embodiments have been made. Similarly, an adhesive layer such as an adhesive sticker, a release paper, a protective film, a base material, and the like may be provided on the optical film of the form. The support is not limited to a plastic film such as TAC or PET, and may be a woven fabric such as a fiber label attached to clothes such as a shirt or a non-woven fabric.

In the optical film of the above embodiment, the design or the design is formed by the regions 30a and 30b in which the orientation state of the liquid crystal material of the liquid crystal layer is different from each other. By making it a trademark), it is possible to add information to those patterns and codes. By doing so, it is possible to attach information such as the product number and the date of manufacture of the optical film itself and the article to which the optical film is attached.

The shape, size, and thickness of the optical film are arbitrary, and a slit (cut) for preventing the replacement of the optical film may be provided in a part of the optical film, and the optical film may have an opening like a donut shape. The portion may be formed.

As the material constituting each layer of the optical film described in the embodiment, any material can be used as long as it fulfills the function of those layers. For example, additives such as dyes and light reflectors that bring decoration and coloring to the liquid crystal layer and the protective film can be added. The liquid crystal material can be composed of not only a material that reflects visible light but also a liquid crystal material that reflects only infrared rays. In this case, the liquid crystal layer of the optical film is visually transparent. In order to observe the authenticity of such an optical film, the optical film may be irradiated with infrared rays and the reflected infrared rays may be detected by an infrared sensor. At this time, the reflected light may be converted into linearly polarized light by a λ / 4 plate and then received light through a polarizing filter that passes through the linearly polarized light.

The embodiments described above are merely examples, and modifications that can be conceived by those skilled in the art can be added to those embodiments.

10 ... Substrate, 20 ... Alignment film, 22 ... Partial area (solvent coating part), 30 ... Liquid crystal layer, 32 ... Design, 40 ... Adhesive, 50 ... Translucent protective film, 60 ... Concavo-convex pattern, 70 ... Rubbing roll, 72 ... Reflective layer, 80 ... Stamp, 82, 84 ... Printing layer, 90 ... Light absorption layer 92 ... Decorative layer, 94 ... Intermediate layer, 100, 102 to 110 ... Optical film, 120 ... Viewer, 130 ... Support body

Claims (3)

An alignment layer and a liquid crystal layer are sequentially provided on the substrate, and the liquid crystal material in a part of the liquid crystal layer and the liquid crystal material in another region are the same, and the liquid crystal material in the part and the liquid crystal in the other region are the same. It is a method of using an optical film whose orientation is different from that of the material.
A separator is provided on the liquid crystal layer of the optical film via a glue layer.
The alignment layer and the substrate are peeled off from the liquid crystal layer provided with the separator via the glue layer to expose the liquid crystal layer.
A method of using the optical film, which comprises peeling the separator from the glue layer and attaching the liquid crystal layer to an article in an exposed state via the glue layer. The method for using an optical film according to claim 1, wherein the liquid crystal layer has a thickness of 0.3 to 9.0 μm. The method for using an optical film according to claim 1 or 2, wherein the breaking strength of the liquid crystal layer is lower than the peeling force of the glue layer.

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