Optical laminate, manufacturing method therefor, smart window including the same, and automobile or building fixture adapting the same

Abstract

To provide a transmittance variable optical laminate.SOLUTION: The present invention pertains to a transmittance variable optical laminate and a manufacturing method therefor, said laminate including: a first polarizing plate; a transparent substrate joined to a first face of the first polarizing plate; a first transparent conductive layer formed on the transparent substrate; a second polarizing plate facing the first polarizing plate; a second transparent conductive layer formed on a first face of the second polarizing plate and facing the first transparent conductive layer; and a liquid crystal layer disposed between the first transparent conductive layer and the second transparent conductive layer. The second transparent conductive layer includes a conductive polymer, the liquid crystal layer includes a polymer network and a liquid crystal compound, and the liquid crystal compound is arranged having a uniform initial orientation. The present invention further pertains to a smart window including the transmittance variable optical laminate, and an automobile or a building fixture to which the smart window is applied.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a variable transmittance optical laminate and a method for producing the same, a smart window including the same, and a fitting for an automobile or building to which the same is applied. [Background technology]

[0002] In general, an external light blocking coating is often applied to glass windows of vehicles such as cars. However, the glass windows of conventional vehicles have a fixed transmittance, and the external light blocking coating also has a fixed transmittance. Therefore, the windows of such conventional vehicles have a fixed overall transmittance, which may lead to accidents. For example, if the overall transmittance is set low, there is no problem during the day when there is sufficient light in the surroundings, but there is a problem that the driver, etc., has difficulty in properly checking the surroundings of the vehicle at night when there is insufficient light in the surroundings. Alternatively, if the overall transmittance is set high, there is a problem that the driver, etc., may be dazzled during the day when there is sufficient light in the surroundings. For this reason, a variable transmittance optical laminate capable of changing the transmittance of light when a voltage is applied has been developed.

[0003] The variable transmittance optical stack is driven by applying a voltage to drive the liquid crystal to change the transmittance, and the variable transmittance optical stacks developed to date are manufactured with spacers in the liquid crystal layer to maintain a cell gap of the liquid crystal layer.

[0004] For example, Japanese Patent Application Publication No. 2018-010035 also discloses a variable transmittance optical laminate in which a liquid crystal layer including a column spacer or ball spacer is applied to maintain a predetermined cell gap.

[0005] However, when column spacers are included in the liquid crystal layer, the manufacturing process becomes complicated, which increases manufacturing costs, and the alignment film is damaged during the process of forming spacers by irradiating ultraviolet light on the photoresist, which causes problems such as changes in transmittance.In addition, when ball spacers are used to maintain the cell gap of the liquid crystal layer, it is impossible to maintain a firm cell gap, making it difficult to maintain a constant optical color in the plane, and inducing a current short circuit in the optical stack.

[0006] In addition, the variable transmittance optical laminate can be laminated with various optical members in multiple layers for the purpose of protecting the bonding surface, providing a bonding surface with other members, polarizing function, etc. In addition, it can be manufactured by various manufacturing methods, but it is preferable to continuously manufacture it by a roll-to-roll (R2R) process including a lamination process from the viewpoint of process economy.

[0007] However, the variable transmittance optical laminate is driven by applying a voltage to drive the liquid crystal to change the transmittance, and the desired transmittance is achieved by having a liquid crystal layer whose phase changes when an electric field is applied to change the transmittance. Therefore, in order to stack two polarizers so that their absorption axes are perpendicular to each other, one polarizer must be rotated 90 degrees after cutting, which makes it difficult to apply the roll-to-roll process.

[0008] In this way, when manufacturing a variable transmittance optical laminate in which the absorption axes of two polarizers are perpendicular to each other, each laminate is manufactured as a separate sheet, each sheet is cut, and then a liquid crystal layer is formed on one of the sheets. The transmission axes of each sheet are perpendicular to each other and bonded together so that the transmittance can be changed when a voltage is applied. This makes the manufacturing process complicated and makes it difficult to reduce costs.

[0009] Therefore, there is a need to develop a variable transmittance optical laminate and a manufacturing method thereof that can maintain a firm cell gap without using a spacer in the liquid crystal layer, can be applied to a roll-to-roll process when forming the liquid crystal layer, and can simplify the manufacturing process. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2018-010035 Summary of the Invention [Problem to be solved by the invention]

[0011] An object of the present invention is to provide a variable transmittance optical laminate that includes a liquid crystal layer containing a polymer network, thereby preventing problems such as damage to the alignment film caused by the use of spacers and difficulty in maintaining a constant optical hue in the plane.

[0012] Another object of the present invention is to provide a variable transmittance optical laminate that includes a polymer network and a liquid crystal layer including liquid crystal compounds arranged with a uniform initial orientation, thereby enabling adjustment of the transmittance of incident light.

[0013] Another object of the present invention is to provide a variable transmittance optical laminate that simplifies the manufacturing process by not including a separate substrate for forming a conductive layer and a separate alignment film for initially aligning a liquid crystal compound.

[0014] Another object of the present invention is to provide a variable transmittance optical laminate that does not include a separate alignment film for initially aligning a liquid crystal compound, thereby significantly reducing the thickness.

[0015] Another object of the present invention is to provide a method for manufacturing a variable transmittance optical laminate, which is capable of applying a roll-to-roll continuous process to form a liquid crystal layer during the manufacture of the variable transmittance optical laminate, and is therefore highly productive and economical.

[0016] Another object of the present invention is to provide a smart window including the variable transmittance optical laminate, and a fitting for an automobile or building to which the smart window is applied.

[0017] However, the problems to be solved by the present invention are not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0018] The present invention relates to a variable transmittance optical laminate including a first polarizing plate, a transparent substrate bonded onto one side of the first polarizing plate, a first transparent conductive layer formed on the transparent substrate, a second polarizing plate facing the first polarizing plate, a second transparent conductive layer formed on one side of the second polarizing plate and facing the first transparent conductive layer, and a liquid crystal layer provided between the first transparent conductive layer and the second transparent conductive layer, wherein the second transparent conductive layer includes a conductive polymer, the liquid crystal layer includes a polymer network and a liquid crystal compound, and the liquid crystal compound is arranged with a uniform initial orientation.

[0019] In a first aspect of the present invention, the liquid crystal behavior mode of the liquid crystal layer may be any one selected from the group consisting of TN (Twisted nematic) mode, STN (Super twisted nematic) mode, IPS (In-plane switching) mode, FFS (Fringe-field switching) mode and VA (Vertical alignment) mode.

[0020] In the second aspect of the present invention, the liquid crystal behavior mode of the liquid crystal layer may be a TN (Twisted nematic) mode.

[0021] In a third aspect of the present invention, the liquid crystal layer may include a cured product of a liquid crystal layer forming composition that includes a polymerizable monomer and a liquid crystal compound.

[0022] In a fourth aspect of the present invention, the liquid crystal layer forming composition may contain 10 to 30% by weight of a polymerizable monomer with respect to the total weight of the composition.

[0023] In a fifth aspect of the present invention, the second transparent conductive layer may have a surface in contact with a liquid crystal layer that is oriented by rubbing.

[0024] In a sixth aspect of the present invention, the conductive polymer is selected from the group consisting of polythiophene, poly(3,4-ethylenedioxythiophene), polyaniline, polyacetylene, polydiacetylene, polyphenylene, polyphenylenevinylene, polyphenylene sulfide, polythienylenevinylene, polythiophenevinylene, polyfluorene, polypyrrole, poly(3,4-ethylenedioxythiophene):polystyrenesulfonate, poly(3,4-ethylenedioxythiophene):camphorsulfonic acid, poly(3,4-ethylenedioxythiophene):toluenesulfonic acid, poly( The polythiophene:dodecylbenzenesulfonic acid may include one or more selected from the group consisting of 3,4-ethylenedioxythiophene):dodecylbenzenesulfonic acid, polyaniline:polystyrenesulfonate, polyaniline:camphorsulfonic acid, polypyrrole:polystyrenesulfonate, polypyrrole:camphorsulfonic acid, polypyrrole:toluenesulfonic acid, polypyrrole:dodecylbenzenesulfonic acid, polythiophene:polystyrenesulfonate, polythiophene:camphorsulfonic acid, polythiophene:toluenesulfonic acid, and polythiophene:dodecylbenzenesulfonic acid.

[0025] In a seventh aspect of the present invention, the second transparent conductive layer may be formed in direct contact with the second polarizing plate without including a separate substrate between the second transparent conductive layer and the second polarizing plate.

[0026] In an eighth aspect of the present invention, the second transparent conductive layer may include an easy-adhesion layer between the second polarizing plate and the second transparent conductive layer, and may be formed in direct contact with the second polarizing plate.

[0027] In a ninth aspect of the present invention, at least one of the first polarizing plate and the second polarizing plate may include one or more functional layers selected from the group consisting of a protective layer, a phase difference adjusting layer, and a refractive index adjusting layer.

[0028] In a tenth aspect of the present invention, the first polarizing plate and the second polarizing plate may have a thickness of 30 μm to 200 μm.

[0029] In an eleventh aspect of the present invention, the variable transmittance optical laminate may further include one or more layers selected from the group consisting of an adhesive layer, an ultraviolet absorbing layer, and a hard coating layer.

[0030] The present invention also relates to a method for producing a variable transmittance optical laminate, the method including the steps of: (a) preparing a first polarizing plate; (b) forming a first transparent conductive layer on a transparent substrate; (c) forming a second transparent conductive layer on a second polarizing plate; (d) coating a liquid crystal layer-forming composition on the second transparent conductive layer to form a liquid crystal layer; (e) bonding the first transparent conductive layer of the laminate formed in step (b) so that it is in contact with the liquid crystal layer of the laminate formed in step (d); and (f) bonding the first polarizing plate prepared in step (a) on the transparent substrate of the laminate formed in step (e), wherein in step (f), the absorption axis of the first polarizing plate and the absorption axis of the second polarizing plate are bonded to each other at right angles in a planar direction, and steps (b) to (e) are performed by a roll-to-roll process.

[0031] In a twelfth aspect of the present invention, the second transparent conductive layer may contain a conductive polymer.

[0032] In a thirteenth aspect, the present invention may further comprise, between the steps (c) and (d), a step of forming a rubbing alignment on a surface of the second transparent conductive layer in contact with the liquid crystal layer.

[0033] In a fourteenth aspect of the present invention, in the step (c), the second transparent conductive layer may be formed in direct contact with the second polarizing plate without including a separate substrate between the second transparent conductive layer and the second polarizing plate.

[0034] In a fifteenth aspect of the present invention, in the step (c), the second transparent conductive layer may be formed in direct contact with the second polarizing plate, including an easy-adhesion layer between the second transparent conductive layer and the second polarizing plate.

[0035] In a sixteenth aspect of the present invention, the liquid crystal behavior mode of the liquid crystal layer may be any one selected from the group consisting of TN (Twisted nematic) mode, STN (Super twisted nematic) mode, IPS (In-plane switching) mode, FFS (Fringe-field switching) mode and VA (Vertical alignment) mode.

[0036] In a seventeenth aspect of the present invention, the liquid crystal behavior mode of the liquid crystal layer may be a TN (Twisted nematic) mode.

[0037] In an eighteenth aspect of the present invention, the liquid crystal layer may include a cured product of a liquid crystal layer forming composition that includes a polymerizable monomer and a liquid crystal compound.

[0038] In a nineteenth aspect of the present invention, the liquid crystal layer may contain a polymer network and a liquid crystal compound.

[0039] The present invention also relates to a smart window comprising the variable transmittance optical laminate.

[0040] The present invention also relates to an automobile in which the smart window is applied to at least one of a front window, a rear window, a side window, a sunroof window, and an interior partition.

[0041] The present invention also relates to a building fixture including the smart window. Effect of the Invention

[0042] According to the variable transmittance optical laminate of the present invention, by including a liquid crystal layer including a polymer network, problems such as damage to the alignment film caused by using a conventional spacer and difficulty in maintaining a constant optical color in the plane can be prevented, and driving safety can be improved compared to conventional optical laminates.

[0043] In addition, according to the variable transmittance optical laminate of the present invention, even if a polymer network is formed in the liquid crystal layer, the liquid crystal compounds can be arranged while maintaining a uniform initial orientation, making it possible to adjust the transmittance of light incident on the optical laminate.

[0044] In addition, according to the variable transmittance optical laminate of the present invention, the conductive layer containing a conductive polymer material can serve both as an electrode for driving the liquid crystal layer and as an alignment film, so that a separate alignment film formation process can be omitted, and the manufacturing process can be simplified compared to conventional optical laminates.

[0045] In addition, according to the variable transmittance optical laminate of the present invention, the conductive layer containing a conductive polymer material can serve both as an electrode for driving the liquid crystal layer and as an alignment film, and therefore, since a separate alignment film for initial alignment of the liquid crystal compound is not included, the thickness can be significantly reduced compared to conventional optical laminates.

[0046] According to the manufacturing method of the variable transmittance optical laminate of the present invention, a roll-to-roll continuous process can be applied to form the liquid crystal layer, and the variable transmittance optical laminate can be manufactured with excellent productivity and economical effects. [Brief description of the drawings]

[0047] [Figure 1] FIG. 1 is a diagram showing a layered structure of a variable transmittance optical layered body according to an embodiment of the present invention. [Figure 2a] FIG. 2a is a diagram showing a laminate structure of a polarizing plate according to one or more embodiments of the present invention. [Figure 2b] FIG. 2b is a diagram showing a stacked structure of a polarizer according to one or more embodiments of the present invention. [Figure 2c] FIG. 2c shows a stacked structure of a polarizer according to one or more embodiments of the present invention. [Figure 2d] FIG. 2d illustrates a stacked structure of a polarizer according to one or more embodiments of the present invention. [Figure 2e] FIG. 2e illustrates a stacked structure of a polarizer according to one or more embodiments of the present invention. [Diagram 3] FIG. 3 is a diagram showing a layered structure of a variable transmittance optical layered body according to another embodiment of the present invention. [Figure 4] FIG. 4 is a diagram illustrating a method for manufacturing a variable transmittance optical laminate according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0048] The present invention relates to a variable transmittance optical laminate including a liquid crystal layer including a polymer network and liquid crystal compounds arranged with a uniform initial orientation. In particular, the present invention relates to a variable transmittance optical laminate that can maintain a cell gap of the liquid crystal layer by the polymer network in the liquid crystal layer, and can prevent problems caused by using a conventional sealant and spacer, and can adjust the transmittance of light incident on the optical laminate since the liquid crystal compounds are arranged with a uniform initial orientation.

[0049] More specifically, the present invention relates to a variable transmittance optical laminate including a first polarizing plate, a transparent substrate bonded to one surface of the first polarizing plate, a first transparent conductive layer formed on the transparent substrate, a second polarizing plate facing the first polarizing plate, a second transparent conductive layer formed on one surface of the second polarizing plate and facing the first transparent conductive layer, and a liquid crystal layer provided between the first transparent conductive layer and the second transparent conductive layer, wherein the second transparent conductive layer includes a conductive polymer, the liquid crystal layer includes a polymer network and a liquid crystal compound, and the liquid crystal compound is arranged with a uniform initial orientation.

[0050] The present invention also relates to a method for producing a variable transmittance optical laminate, which is excellent in productivity and economy by producing the variable transmittance optical laminate by a roll-to-roll continuous process.

[0051] More specifically, the method includes the steps of: (a) preparing a first polarizing plate; (b) forming a first transparent conductive layer on a transparent substrate; (c) forming a second transparent conductive layer on a second polarizing plate; (d) forming a liquid crystal layer by coating a liquid crystal layer-forming composition on the second transparent conductive layer; (e) bonding the first transparent conductive layer of the laminate formed in step (b) so that it is in contact with the liquid crystal layer of the laminate formed in step (d); and (f) bonding the first polarizing plate prepared in step (a) on the transparent substrate of the laminate formed in step (e), wherein in step (f), the absorption axis of the first polarizing plate and the absorption axis of the second polarizing plate are bonded to each other at right angles in a planar direction, and steps (b) to (e) are performed by a roll-to-roll process.

[0052] The variable transmittance optical laminate of the present invention is particularly suitable for technical fields in which light transmittance can be changed by applying a voltage, and can be used, for example, in smart windows.

[0053] A smart window is an optical structure that controls the amount of light or heat passing through by changing the light transmittance according to the application of an electric signal. That is, a smart window is designed to be able to change to a transparent, opaque or translucent state according to a voltage, and is also called variable transmittance glass, light control glass or smart glass.

[0054] A smart window can be used as a partition for dividing or protecting privacy in the interior space of a vehicle or building, or as a light window placed in an opening of a building. It can also be used as a highway sign, a bulletin board, a number board, a clock or an advertising screen, and can be used to replace glass in vehicles such as windows or sunroofs of cars, buses, airplanes, ships or trains.

[0055] The variable transmittance optical laminate of the present invention can also be used in smart windows in the various technical fields described above, but since the conductive layer is directly formed on the polarizing plate, no separate substrate is required for forming the conductive layer, and therefore the thickness is thin and the bending characteristics are advantageous, and the variable transmittance optical laminate of the present invention can be particularly preferably used in smart windows for vehicles or buildings. In one or more embodiments, the smart window to which the variable transmittance optical laminate of the present invention is applied can be used in transportation, for example, front windows, rear windows, side windows and sunroof windows of automobiles, or building fixtures, and can be used not only for blocking external light, but also for dividing the interior space of automobiles or buildings, such as interior partitions, or for privacy protection.

[0056] Hereinafter, the embodiments of the present invention will be described in more detail with reference to the drawings. However, the following drawings attached to this specification are intended to illustrate preferred embodiments of the present invention and, together with the above-mentioned invention content, serve to facilitate a better understanding of the technical concept of the present invention, and therefore the present invention should not be interpreted as being limited only to the matters depicted in these drawings.

[0057] The terms used in this specification are for the purpose of explaining the embodiments and are not intended to limit the present invention. In this specification, the singular form includes the plural form unless otherwise specified in the text. For example, the term "polarizing plate" used in this specification may mean at least one polarizing plate of the first polarizing plate and the second polarizing plate, and the term "transparent conductive layer" may mean at least one transparent conductive layer of the first transparent conductive layer and the second transparent conductive layer.

[0058] As used herein, the terms "comprises" and / or "comprising" are used in a sense that does not exclude the presence or addition of one or more other components, steps, operations and / or elements other than the stated components, steps, operations and / or elements. The same reference numerals refer to the same components throughout the specification.

[0059] Spatially relative terms such as "below," "bottom," "lower," "upper," "top," and the like can be used to easily describe the relationship of one element or component to another element or component as depicted in the drawings. Spatially relative terms should be understood to include different orientations of elements in use or operation in addition to the orientation depicted in the drawings. For example, if an element depicted in the drawings is turned upside down, an element described as "below" or "below" another element may be placed "above" the other element. Thus, the exemplary term "below" may include both an orientation of below and above. Elements may be oriented in other directions, and thus the spatially relative terms may be interpreted accordingly.

[0060] As used herein, the "planar direction" may be interpreted as the direction perpendicular to the polarizer and / or transparent conductive layer, ie, the direction viewed from the user's viewing side.

[0061] <Variable transmittance optical laminate> FIG. 1 is a diagram showing the stack structure of a variable transmittance optical laminate according to one embodiment of the present invention, FIGS. 2a to 2e are diagrams showing the stack structure of a polarizing plate according to one or more embodiments of the present invention, and FIG. 3 is a diagram showing the stack structure of a variable transmittance optical laminate according to another embodiment of the present invention.

[0062] Referring to FIG. 1, a variable transmittance optical stack according to one embodiment of the present invention may include a first polarizer 100-1, a second polarizer 100-2, a first transparent conductive layer 200-1, a second transparent conductive layer 200-2, a transparent substrate 150, and a liquid crystal layer 300.

[0063] Referring to FIG. 2, the polarizing plate 100 includes a polarizer 110, and may further include functional layers, such as a protective layer 120, a phase difference control layer 130, and a refractive index control layer 140, on one or both sides of the polarizer 110. For example, the polarizing plate 100 may include a polarizer 110 and a protective layer 120 stacked on one or both sides of the polarizer 110 (see FIGS. 2a and 2b), a polarizer 110, a protective layer 120 stacked on one side of the polarizer 110, and a phase difference adjusting layer 130 stacked on the other side of the polarizer 110 opposite to the one side (see FIG. 2c), a polarizer 110, a protective layer 120 stacked on one side of the polarizer, and a phase difference adjusting layer 130 and a refractive index adjusting layer 140 stacked in sequence on the other side of the polarizer 110 opposite to the one side (see FIG. 2d), or a polarizer 110, a protective layer 120 stacked on one side of the polarizer, and a protective layer 120 and a phase difference adjusting layer 130 stacked in sequence on the other side of the polarizer 110 opposite to the one side (see FIG. 2e).

[0064] The polarizer 110 may be a conventional or later developed polarizer, for example, a stretched type polarizer or a coated type polarizer.

[0065] In one embodiment, the stretched polarizer may include a stretched polyvinyl alcohol (PVA)-based resin. The polyvinyl alcohol (PVA)-based resin may be a polyvinyl alcohol-based resin obtained by saponifying a polyvinyl acetate-based resin. Examples of polyvinyl acetate-based resins include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. The other monomers may be unsaturated carboxylic acid-based, unsaturated sulfonic acid-based, olefin-based, vinyl ether-based, and acrylamide-based monomers having an ammonium group. The polyvinyl alcohol (PVA)-based resin may be modified, for example, polyvinyl formal or polyvinyl acetal modified with aldehydes.

[0066] In one embodiment, the coating type polarizer may be formed by a liquid crystal coating composition, and the liquid crystal coating composition may include a reactive liquid crystal compound and a dichroic dye.

[0067] The reactive liquid crystal compound may refer to a compound that includes, for example, a mesogen skeleton and further includes one or more polymerizable functional groups. Such reactive liquid crystal compounds are variously known under the name of RM (Reactive Mesogen). The reactive liquid crystal compound can be polymerized by light or heat to form a cured film in which a polymer network is formed while maintaining the liquid crystal alignment.

[0068] The reactive liquid crystal compound may be a monofunctional or polyfunctional reactive liquid crystal compound. The monofunctional reactive liquid crystal compound is a compound having one polymerizable functional group, and the polyfunctional reactive liquid crystal compound is a compound having two or more polymerizable functional groups.

[0069] The dichroic dye is a component contained in the liquid crystal coating composition that imparts polarization properties and has a property that the absorbance in the long axis direction of the molecule is different from that in the short axis direction. The dichroic dye may be a dichroic dye that has been used or will be developed in the future, and may include at least one dye selected from the group consisting of azo dyes, anthraquinone dyes, perylene dyes, merocyanine dyes, azomethine dyes, phthaloperylene dyes, indigo dyes, dioxazine dyes, polythiophene dyes, and phenoxazine dyes.

[0070] The liquid crystal coating composition may further include a solvent capable of dissolving the reactive liquid crystal compound and the dichroic dye, such as propylene glycol monomethyl ether acetate (PGMEA), methyl ethyl ketone (MEK), xylene, chloroform, etc. The liquid crystal coating composition may further include a leveling agent, a polymerization initiator, etc., within a range that does not impair the polarization properties of the coating film.

[0071] The protective layer 120 serves to preserve the polarization characteristics of the polarizer 110 from post-processing and external environments, and may be implemented in the form of a protective film.

[0072] 2a and 2b, the protective layer 120 may be formed on one or both sides of the polarizer 110 in direct contact therewith, but is not limited thereto. For example, the protective layer may be used as a multi-layer structure in which one or more protective layers are continuously stacked, or may be formed in direct contact with other functional layers.

[0073] In one or more embodiments, the protective layer 120 may include one or more selected from the group consisting of polyethylene terephthalate (PET), polyethylene isophthalate (PEI), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), diacetyl cellulose (diacetyl cellulose), triacetyl cellulose (TAC), polycarbonate (PC), polyethylene (PE), polypropylene (PP), polymethyl acrylate (PMA), polymethyl methacrylate (PMMA), polyethyl acrylate (PEA), polyethyl methacrylate (PEMA), and cyclic olefin polymer (COP).

[0074] The retardation control layer 130 is for complementing the optical properties of the optical laminate and may be implemented in the form of a retardation film, etc., or may use a conventional or later developed retardation film, etc. For example, a quarter wave plate (1 / 4 wave plate) or a half wave plate (1 / 2 wave plate) for delaying the phase of light may be used, and these may be used alone or in combination.

[0075] The phase difference adjusting layer 130 may be formed on one surface of the polarizer 110 in direct contact therewith as shown in Fig. 2c and Fig. 2d, but is not limited thereto. For example, as shown in Fig. 2e, the phase difference adjusting layer 130 may be formed on one surface of the protective layer 120, and the polarizer 110, the protective layer 120, and the phase difference adjusting layer 130 may be sequentially stacked.

[0076] The retardation adjusting layer 130 may be a polymer stretched film obtained by stretching a polymer film capable of imparting optical anisotropy by stretching in an appropriate manner, or a liquid crystal polymer film.

[0077] In one embodiment, the polymer stretched film may be a polymer layer including polyolefins such as polyethylene (PE) or polypropylene (PP), cycloolefin polymers (COP) such as polynorbornene, polyesters such as polyvinyl chloride (PVC), polyacrylonitrile (PAN), polysulfone (PSU), acrylic resins, polycarbonate (PC), and polyethylene terephthalate (PET), polyacrylate, cellulose ester polymers such as polyvinyl alcohol (PVA) or triacetyl cellulose (TAC), or copolymers of two or more monomers among the monomers forming the polymers.

[0078] The method for obtaining the polymer stretched film is not particularly limited, and for example, the polymer material is molded into a film and then stretched. The method for forming the film is not particularly limited, and the film can be molded into a film by known methods such as injection molding, sheet molding, blow molding, injection blow molding, inflation molding, extrusion molding, foam molding, and cast molding, and secondary processing molding methods such as compressed air molding and vacuum molding may also be used. Among them, extrusion molding and cast molding are preferably used. At this time, for example, an extruder equipped with a T-die, a circular die, or the like can be used to extrude the unstretched film. When obtaining a molded product by extrusion molding, a material in which various resin components, additives, etc. are melt-kneaded in advance can be used, or the product can be molded through melt-kneading during extrusion molding. In addition, various resin components can be dissolved using a solvent common to various resin components, such as chloroform or methylene dichloride, and then cast-dried and solidified to cast-mold the unstretched film.

[0079] The polymer stretched film may be produced by uniaxially stretching the formed film in the mechanical direction (MD, lengthwise or longitudinal direction) or uniaxially stretching the formed film in the transverse direction (TD, widthwise or transverse direction) of the mechanical direction. Also, a biaxially stretched film may be produced by stretching the formed film by a sequential biaxial stretching method of roll stretching and tenter stretching, a simultaneous biaxial stretching method by tenter stretching, a biaxial stretching method by tubular stretching, or the like.

[0080] The liquid crystal polymer film may include a reactive liquid crystal compound in a polymerized state. The reactive liquid crystal compound may be the same as that of the coating type polarizer.

[0081] In one or more embodiments, the thickness of the retardation adjusting layer 130 may be 10 to 100 μm in the case of a polymer stretched film, and may be 0.1 to 5 μm in the case of a liquid crystal polymer film.

[0082] The refractive index adjustment layer 140 is provided to compensate for the refractive index difference of the optical laminate caused by the transparent conductive layer 200, and may serve to improve visibility by reducing the refractive index difference. The refractive index adjustment layer 140 may also be provided to correct a color caused by the transparent conductive layer 200. Meanwhile, when the transparent conductive layer has a pattern, the refractive index adjustment layer 140 can compensate for the transmittance difference between a patterned region where the pattern is formed and a non-patterned region where the pattern is not formed.

[0083] Specifically, the transparent conductive layer 200 is stacked adjacent to another member (e.g., the polarizer 110, etc.) having a different refractive index from the transparent conductive layer 200, and a difference in light transmittance may be induced due to the difference in refractive index with the adjacent layer, and in particular, when a pattern is formed on the transparent conductive layer, a problem may occur in which the patterned region and the non-patterned region are visually distinguishable. Therefore, by including the refractive index adjusting layer 140, the refractive index is compensated for, and the difference in light transmittance of the optical laminate can be reduced, and in particular, when a pattern is formed on the transparent conductive layer, the patterned region and the non-patterned region are visually distinguishable.

[0084] In one embodiment, the refractive index of the refractive index adjusting layer 140 may be appropriately selected depending on the material of the adjacent member, and may be preferably 1.4 to 2.6, and more preferably 1.4 to 2.4. In this case, light loss due to a sharp difference in refractive index between the transparent conductive layer 200 and the other member such as the polarizer 110 can be prevented.

[0085] The refractive index adjustment layer 140 is not particularly limited as long as it can prevent a sharp refractive index difference between other components such as the polarizer 110 and the transparent conductive layer 200. The refractive index adjustment layer 140 may be formed from a compound used to form a conventional or later developed refractive index adjustment layer, for example, a refractive index adjustment layer-forming composition containing a polymerizable isocyanurate compound. In one embodiment, the polarizing plate 100 may further include other functional layers in addition to the above-mentioned functional layers to supplement or enhance the properties of the polarizer, for example, an overcoat layer to further improve mechanical durability.

[0086] In one or more embodiments, the polarizing plate 100 may have a thickness of 30 to 200 μm, preferably 30 to 170 μm, and more preferably 50 to 150 μm, in which case the polarizing plate 100 can be used to manufacture an optical laminate having a small thickness while maintaining optical properties.

[0087] The transparent conductive layer 200 is provided for driving the liquid crystal layer 300, and may be formed in direct contact with the polarizer 100, or may be formed by coating on a separate transparent substrate 150.

[0088] For example, as shown in FIG. 1, a first transparent conductive layer 200-1 may be coated on a transparent substrate 150, a first polarizer 100-1 may be formed on the transparent substrate 150, and a second transparent conductive layer 200-2 may be formed in direct contact with the second polarizer 100-2.

[0089] Conventional optical laminates used in the manufacture of smart windows, etc., are manufactured by forming a conductive layer for driving liquid crystal on one side of a substrate and bonding the other side of the substrate with a polarizing plate. However, the variable transmittance optical laminate according to the present invention does not include a separate substrate for forming a conductive layer, and directly forms a conductive layer on one side of a polarizing plate, thereby reducing the thickness of the laminate and improving the transmittance and bending characteristics in a transmission mode.

[0090] In one embodiment, the transparent conductive layer 200 may be formed by directly depositing and coating on one surface of the transparent substrate 150 or the second polarizer 100-2. In this case, the transparent conductive layer 200 may be formed by directly contacting the pre-treated surface of the transparent substrate 150 or the second polarizer 100-2 after performing a pre-treatment such as a corona treatment or a plasma treatment on one surface of the transparent substrate 150 or the second polarizer 100-2 in order to improve the adhesive strength with the transparent substrate 150 or the second polarizer 100-2. The pre-treatment is not limited to a corona treatment or a plasma treatment, and any pre-treatment process may be used as long as it does not impair the object of the present invention.

[0091] In another embodiment, the transparent conductive layer 200 may be formed in direct contact with the transparent substrate 150 or the second polarizer 100-2 via an easy-adhesion layer (not shown) provided on one surface of the transparent substrate 150 or the second polarizer 100-2 in order to improve adhesion to the transparent substrate 150 or the second polarizer 100-2. The easy-adhesion layer may be made of the materials described for the adhesive layer among other members described later, but is not limited thereto.

[0092] The transparent substrate 150 is a structural base for forming the first transparent conductive layer 200-1, and is not particularly limited as long as it is a transparent material that does not reduce transmittance. Preferred examples of the transparent substrate 150 include polyethylene terephthalate (PET), polyethylene isophthalate (PEI), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), diacetyl cellulose, triacetyl cellulose (TAC), polycarbonate (PC), polyethylene (PE), polypropylene (PP), polymethyl acrylate (PMA), polymethyl methacrylate (PMMA), polyethyl acrylate (PEA), polyethyl methacrylate (PEMA), and cyclic olefin polymers. The resin composition may include one or more selected from the group consisting of polyimide (COP), polyimide (PI), and polyamideimide (PAI), and preferably includes one or more selected from polyimide (PI) and polyamideimide (PAI).

[0093] The transparent conductive layer 200 may be formed by depositing and coating on one surface of the transparent substrate 150 or the second polarizer 100-2 by a method commonly used in the art. For example, the transparent conductive layer 200 may be formed by selecting an appropriate process from coating processes such as spin coating, roller coating, bar coating, dip coating, gravure coating, curtain coating, die coating, spray coating, doctor coating, and kneader coating; printing (coating) processes such as screen printing, spray printing, inkjet printing, relief printing, intaglio printing, and planographic printing; and deposition processes such as CVD (chemical vapor deposition), PVD (physical vapor deposition), and PECVD (plasma enhanced chemical vapor deposition).

[0094] In the variable transmittance optical laminate of the present invention, the first transparent conductive layer 200-1 preferably has a transmittance of 50% or more for visible light, and may, for example, include one or more selected from the group consisting of transparent conductive oxides, metals, carbon-based materials, conductive polymers, conductive inks, and nanowires, but is not limited thereto, and any conventional or later developed transparent conductive layer material may be used.

[0095] In one or more embodiments, the transparent conductive oxide may include one or more selected from the group consisting of indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), aluminum zinc oxide (AZO), gallium zinc oxide (GZO), florin tin oxide (FTO), zinc oxide (ZnO), etc. The metal may include one or more selected from the group consisting of gold (Au), silver (Ag), copper (Cu), aluminum (Al), platinum (Pt), palladium (Pd), chromium (Cr), titanium (Ti), tungsten (W), niobium (Nb), tantalum (Ta), vanadium (V), iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), zinc (Zn), and alloys containing at least one of these, for example, a silver-palladium-copper (APC) alloy or a copper-calcium (CuCa) alloy. The carbon-based material may include at least one selected from the group consisting of carbon nanotubes (CNTs) and graphene.The conductive polymer may be a conventional or later developed conductive polymer material, for example, polythiophene, poly(3,4-ethylenedioxythiophene), polyaniline, polyacetylene, polydiacetylene, polyphenylene, polyphenylenevinylene, polyphenylene sulfide, polythienylenevinylene, polythiophenevinylene, polyfluorene, polypyrrole, poly(3,4-ethylenedioxythiophene):polystyrenesulfonate, poly(3,4-ethylenedioxythiophene):camphorsulfonic acid, poly(3,4-ethylenedioxythiophene):toluene ... The conductive ink may be an ink containing a metal powder and a curable polymer binder, and the nanowire may be, for example, a silver nanowire (AgNW). The first transparent conductive layer 200-1 may be formed in a structure of two or more layers by combining the above materials. For example, the first transparent conductive layer 200-1 may be formed in a two-layer structure including a metal layer and a transparent conductive oxide layer so as to reduce the reflectance of incident light and increase the transmittance.

[0096] In the variable transmittance optical laminate of the present invention, the second transparent conductive layer 200-2 may include the conductive polymer, and may preferably have a visible light transmittance of 50% or more. In this case, even if the transparent conductive layer is deformed by an external stress, it is possible to prevent cracks from occurring in the transparent conductive layer, and thus to prevent an excessive increase in surface resistance.

[0097] In one embodiment, the second transparent conductive layer 200-2 may have a surface in contact with the liquid crystal layer 300 that is oriented by rubbing. The conductive polymer contained in the second transparent conductive layer 200-2 of the present invention can form a certain groove on the surface, unlike a transparent conductive layer containing a metal component, and thus the liquid crystal compound in the liquid crystal layer can be aligned at a desired position and direction. In this case, the second transparent conductive layer 200-2 can function as an electrode for driving the liquid crystal layer and also as an alignment film. Since a separate alignment film is not included, it is possible to manufacture an optical laminate with a thinner thickness and the manufacturing process can be simplified.

[0098] The liquid crystal layer 300 included in the variable transmittance optical laminate of the present invention includes a polymer network 310 as described below, and the polymer network can be formed by a crosslinking reaction of a polymerizable compound. In order for the liquid crystal compound 320 in the liquid crystal layer to maintain a uniform initial alignment when the polymer network 310 is formed, an alignment film having a strong surface anchoring energy is required. In the present invention, instead of a separate alignment film, a transparent conductive layer, preferably a surface of the second transparent conductive layer in contact with the liquid crystal layer, can be treated with a rubbing method and / or a photoalignment method so that an alignment angle is formed directly on the surface. Methods for forming an alignment film include a rubbing method using a rubbing process and a photoalignment method using ultraviolet light, and the photoalignment method generally has a weaker surface anchoring energy than the rubbing method. More specifically, the alignment film formed by the rubbing method has a surface anchoring energy of about 1×10 -3 J / m 2 The surface anchoring energy of the alignment film formed by the photoalignment method is about 1×10 -6 J / m 2 Therefore, in order to maintain a uniform initial alignment of the liquid crystal compound 320 when the polymer network 310 is formed in the liquid crystal layer 300, it is preferable that the surface of the second transparent conductive layer 200-2 in contact with the liquid crystal layer 300 is oriented by rubbing using a rubbing method.

[0099] In one embodiment, the transparent conductive layer 200 may have a thickness of 1 μm or less, preferably 10 nm to 500 nm, and more preferably 30 nm to 200 nm. In this case, the transparent conductive layer 200 has a predetermined transmittance, and does not significantly change in characteristics due to external stress, making it possible to manufacture an optical laminate with a thin thickness.

[0100] The liquid crystal layer 300 can change the driving mode of the optical stack to a light-transmitting mode or a light-blocking mode by adjusting the transmittance of light incident in one or more directions in response to the electric field generated by the transparent conductive layer 200.

[0101] The liquid crystal layer 300 may include a polymer network 310 and a liquid crystal compound 320, and may be, for example, provided between the first transparent conductive layer 200-1 and the second transparent conductive layer 200-2 in the light control region and located within the space provided by the polymer network 310.

[0102] Conventional optical laminates must include a sealant and a spacer to maintain a certain space, i.e., a cell gap, in which liquid crystal compounds are provided in the liquid crystal layer. However, when a column spacer is included in the liquid crystal layer to maintain the cell gap, the manufacturing process becomes complicated, leading to an increase in manufacturing costs, and the alignment film is damaged during the process of forming spacers by irradiating ultraviolet light on a photoresist, leading to a change in transmittance. In addition, when a ball spacer is used to maintain the cell gap of the liquid crystal layer, it is impossible to maintain a firm cell gap, it is difficult to maintain a constant optical color in the plane, and current shorts of the optical laminate are induced. In addition, when a sealant is used to maintain the cell gap of the liquid crystal layer, there are problems such as a decrease in apparent quality due to the visibility of the sealant, and defects such as breakage of the sealant during handling of the optical laminate, or defects due to thickness differences with the spacers included in the sealant.

[0103] The liquid crystal layer 300 included in the variable transmittance optical laminate of the present invention includes a polymer network 310 together with a liquid crystal compound 320, and therefore can properly maintain the cell gap of the liquid crystal layer without using a separate sealant and / or spacer. In addition, since the cell gap is maintained by a single polymer network configuration, not a combination of a sealant and a spacer, there is an advantage in that defects due to thickness differences between the sealant and the spacer can be fundamentally prevented.

[0104] The liquid crystal compound is not particularly limited as long as it is driven by an electric field and can control the light transmittance, and any conventional or later developed liquid crystal compound can be used. For example, the contents regarding the reactive liquid crystal compound of the coating type polarizer described above can be similarly applied.

[0105] The liquid crystal compound may include a chiral nematic (cholesteric) liquid crystal compound, and the chiral nematic liquid crystal compound may include a nematic liquid crystal compound and a chiral compound.

[0106] The nematic liquid crystal compound has long rod-like molecules arranged in parallel to each other, and although there is no regularity in the center position of the molecule, it has order in the molecular axis direction. Since each molecule of the nematic liquid crystal compound can move freely in the long axis direction, it has low viscosity and good fluidity, and since the direction of each molecule is almost the same up and down, polarization is offset and generally does not show ferroelectricity. The type of the nematic liquid crystal compound is not particularly limited, and any compound containing a mesogen group is possible.

[0107] The chiral compounds are compounds that have symmetrical structures like the relationship between a right hand and a left hand, and have the same chemical structure and physical properties, but are not identical in structure because they are mirror images of each other. When a certain amount of the chiral compound is contained in the nematic liquid crystal compound, it induces a helical period. The type of the chiral compound is not particularly limited as long as it can induce the desired helical period without damaging the liquid crystal property, for example, the nematic regularity, of the liquid crystal compound.

[0108] A chiral compound for inducing a helical period in a liquid crystal compound must have at least chirality in its molecular structure. Examples of the chiral compound include compounds having one or more asymmetric carbons, compounds having an asymmetric point on a heteroatom such as chiral amine or chiral sulfoxide, or compounds having an axially asymmetric, optically active site having an axial member such as cumulene or binaphthol.

[0109] The chiral compound may be, for example, a low molecular weight compound having a molecular weight of 1,500 or less. For example, the chiral compound may be a commercially available chiral nematic liquid crystal, such as chiral dopant liquid crystal S-811 manufactured by Merck or Paliocolor LC756 (manufactured by BASF), but is not limited thereto.

[0110] The chiral nematic liquid crystal compound may contain 75 to 99% by weight of the nematic liquid crystal compound and 1 to 25% by weight of the chiral compound based on the total weight of the chiral nematic liquid crystal compound, but is not limited thereto. The contents of the nematic liquid crystal compound and the chiral compound may be appropriately adjusted within the above ranges to adjust the helical period, i.e., pitch, of the chiral nematic liquid crystal compound. The pitch of the chiral nematic liquid crystal compound is not particularly limited, but may be 5 to 20 μm.

[0111] The liquid crystal behavior mode of the liquid crystal layer 300 is not particularly limited, and for example, TN (Twisted nematic) mode, STN (Super twisted nematic) mode, IPS (In-plane switching) mode, FFS (Fringe-field switching) mode, and VA (Vertical alignment) mode can be used. From the viewpoint of controlling light transmittance, it is preferable to use TN (Twisted nematic) mode.

[0112] Polymer dispersed liquid crystal (PDLC) is known as an example of a conventional liquid crystal layer containing a polymer. In the polymer dispersed liquid crystal, liquid crystal compounds are phase-separated into droplets or capsules in a polymer, and the phase-separated droplet or capsule-type liquid crystal compounds are arranged in an irregular direction and cannot have a fixed initial orientation. That is, in the polymer dispersed liquid crystal (PDLC), when no voltage is applied, the liquid crystal compounds have an irregular arrangement and scatter the incident light, thereby maintaining an opaque state (light-shielding mode), and when a voltage is applied, the liquid crystal compounds are aligned in one direction and pass the incident light, thereby becoming a transparent state (light-transmitting mode). However, the light-shielding mode of the polymer dispersed liquid crystal (PDLC) uses the property that the incident light is scattered by the irregular arrangement of the liquid crystal compounds, so it is not possible to control the light scattered in any direction, and there is a technical limit that the light-shielding rate is somewhat unsatisfactory, and it has been pointed out that there are disadvantages in that it is necessary to maintain a state in which a voltage is applied, resulting in high power consumption.

[0113] The liquid crystal layer 300 of the present invention includes a polymer network 310 and a liquid crystal compound 320, and the liquid crystal compound 320 is arranged with a uniform initial alignment. The liquid crystal layer 300 of the present invention is different from a conventional polymer dispersed liquid crystal (PDLC) in that the liquid crystal compound 320 included in the polymer network 310 is not phase-separated into droplets or capsules, but exists in a mixed form with the polymer network 310 and is arranged with a uniform initial alignment in the liquid crystal layer. As described above, the liquid crystal layer 300 of the present invention including the polymer network 310 and the liquid crystal compound 320 arranged with a uniform initial alignment can realize a light transmission mode and a light blocking mode by controlling the transmittance of light incident in one or more directions according to the electric field generated by the transparent conductive layer 200. Therefore, it can show a superior light blocking rate compared to the conventional polymer dispersed liquid crystal which realizes a light blocking mode by scattering the incident light. In addition, the variable transmittance optical laminate of the present invention can realize a light transmission mode without applying voltage by appropriately adjusting the transmission axis of the polarizer 100 and the optical axis of the liquid crystal layer 300. Also, compared to conventional polymer dispersed liquid crystals in which liquid crystals are randomly arranged, the applied voltage required for driving is lower, which is advantageous in that it can reduce power consumption compared to conventional polymer dispersed liquid crystals.

[0114] The liquid crystal layer 300 may include a cured product of a liquid crystal layer forming composition including a polymerizable monomer and a liquid crystal compound.

[0115] The polymerizable monomer means a compound that forms a polymer network by a photopolymerization reaction or a thermal polymerization reaction, and is not particularly limited. For example, the polymerizable monomer may include an acrylate monomer, and may include one or more monomers selected from the group consisting of isobornyl acrylate, caprolactone acrylate, triethylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, and dipentaerythritol pentaacrylate.

[0116] The polymerizable monomer may include one or more monomers selected from monofunctional to tetrafunctional monomers, and preferably includes a trifunctional monomer. The multifunctional monomer has an advantage that it has excellent compatibility with the liquid crystal without giving any impact to the liquid crystal, and can exhibit appropriate phase separation with the liquid crystal.

[0117] The liquid crystal layer forming composition may contain 10 to 30 wt % of the polymerizable monomer based on the total weight of the composition, and preferably 10 to 20 wt %. When the liquid crystal layer forming composition contains the polymerizable monomer in the above content range, it is preferable because the polymer network formed therefrom has a sufficient degree of hardening, which is advantageous in that the cell gap of the liquid crystal layer can be stably maintained and excellent light transmittance and adhesion can be obtained.

[0118] The method of forming the liquid crystal layer 300 using the composition for forming a liquid crystal layer is not particularly limited, and for example, the composition for forming a liquid crystal layer can be applied onto the second transparent conductive layer 200-2 having a rubbing-aligned surface, and then photocured or thermally cured to form the liquid crystal layer.

[0119] The variable transmittance optical laminate according to the present invention includes a polymer network 310 in the liquid crystal layer 300, so that a stable cell gap can be maintained without including a sealant or spacer. In addition, if necessary, the variable transmittance optical laminate may further include at least one of a sealant and a spacer within a range that does not impair the object of the present invention.

[0120] The sealant may include a curable resin as a base resin. The base resin may be a UV-curable resin or a thermosetting resin known in the art to be used for sealants. The UV-curable resin may be a polymer of a UV-curable monomer. The thermosetting resin may be a polymer of a thermosetting monomer.

[0121] The base resin of the sealant may be, for example, an acrylate-based resin, an epoxy-based resin, a urethane-based resin, a phenol-based resin, or a mixture of the resins. In one embodiment, the base resin may be an acrylate-based resin, and the acrylate-based resin may be a polymer of an acrylic monomer. The acrylic monomer may be, for example, a polyfunctional acrylate. In another embodiment, the sealant may further include a monomer component in the base resin. The monomer component may be, for example, a monofunctional acrylate. In this specification, a monofunctional acrylate may mean a compound having one acrylic group, and a polyfunctional acrylate may mean a compound having two or more acrylic groups. The curable resin may be cured by irradiation with ultraviolet light and / or heating. The ultraviolet irradiation conditions or heating conditions may be appropriately performed within a range that does not impair the purpose of the present application. The sealant may further include an initiator, for example, a photoinitiator or a thermal initiator, as necessary.

[0122] The sealant can be formed by a method commonly used in the art, for example, by drawing the sealant onto the outer periphery (i.e., non-active area) of the liquid crystal layer using a dispenser equipped with a nozzle.

[0123] The spacer may include at least one of a ball spacer and a column spacer, and is preferably a ball spacer. The number of spacers may be one or more, and it is more preferable that the spacer has a diameter of 1 to 10 μm. When viewed in a planar direction, the area of ​​the spacer in the liquid crystal layer 300 is preferably 0.01 to 10% of the area of ​​the liquid crystal layer 300 in terms of improving the user's visibility and the transmittance in the light-transmitting mode.

[0124] The variable transmittance optical laminate of the present invention may further include other components within the scope of the present invention, for example, may further include an adhesive layer 400 (see FIG. 3), or may further include an ultraviolet absorbing layer, a hard coating layer, etc.

[0125] The adhesive layer 400 may be formed using an adhesive or pressure-sensitive adhesive, and preferably has an appropriate adhesive strength so as to prevent peeling, air bubbles, etc. from occurring when the optical laminate is handled, as well as transparency and thermal stability.

[0126] The adhesive may be any conventional or later developed adhesive, for example a light curable adhesive.

[0127] The photocurable adhesive exhibits strong adhesive strength by being crosslinked and cured when exposed to active energy rays such as ultraviolet (UV) rays and electron beams (EB), and may be composed of reactive oligomers, reactive monomers, photopolymerization initiators, etc.

[0128] The reactive oligomer is an important component that determines the properties of the adhesive, and forms a polymer bond by photopolymerization to form a hardened coating. Usable reactive oligomers include polyester resins, polyether resins, polyurethane resins, epoxy resins, polyacrylic resins, silicone resins, etc.

[0129] The reactive monomer functions as a crosslinking agent and a diluent for the reactive oligomer, and affects the adhesive properties. Usable reactive monomers include monofunctional monomers, polyfunctional monomers, epoxy monomers, vinyl ethers, cyclic ethers, and the like.

[0130] The photopolymerization initiator absorbs light energy to generate radicals or cations to initiate photopolymerization, and may be selected from those suitable for the photopolymerizable resin.

[0131] The adhesive may be a conventional or later developed adhesive, and in one or more embodiments, may be an acrylic adhesive, a rubber adhesive, a silicone adhesive, a urethane adhesive, a polyvinyl alcohol adhesive, a polyvinylpyrrolidone adhesive, a polyacrylamide adhesive, a cellulose adhesive, a vinyl alkyl ether adhesive, etc. The adhesive is not particularly limited as long as it has adhesive strength and viscoelasticity, but from the viewpoint of availability, etc., it may be preferably an acrylic adhesive, and may contain, for example, a (meth)acrylate copolymer, a crosslinking agent, and a solvent.

[0132] The crosslinking agent may be a conventional or later developed crosslinking agent, and may include, for example, a polyisocyanate compound, an epoxy resin, a melamine resin, a urea resin, a dialdehyde, a methylol polymer, or the like, and preferably includes a polyisocyanate compound.

[0133] The solvent may include a typical solvent used in the field of resin compositions, such as alcohol compounds such as methanol, ethanol, isopropanol, butanol, and propylene glycol methoxy alcohol; ketone compounds such as methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, and dipropyl ketone; acetate compounds such as methyl acetate, ethyl acetate, butyl acetate, and propylene glycol methoxy acetate; cellosolve compounds such as methyl cellosolve, ethyl cellosolve, and propyl cellosolve; and hydrocarbon compounds such as hexane, heptane, benzene, toluene, and xylene. These may be used alone or in combination of two or more.

[0134] The thickness of the adhesive layer 400 may be appropriately determined depending on the type of resin acting as an adhesive, adhesive strength, the environment in which the adhesive is used, etc. In one embodiment, the adhesive layer may have a thickness of 0.01 to 50 μm, preferably 0.05 to 20 μm, and more preferably 0.1 to 10 μm, in order to ensure sufficient adhesive strength and minimize the thickness of the optical laminate.

[0135] The ultraviolet absorbing layer is not particularly limited as long as it is used to prevent deterioration of the optical laminate due to ultraviolet rays. For example, it may be a salicylic acid-based ultraviolet absorber (phenyl salicylate, p-tert-butyl salicylate, etc.), a benzophenone-based ultraviolet absorber (2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, etc.), a benzotriazole-based ultraviolet absorber (2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-t 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3'-(3'',4'',5'',6''-tetrahydrophthalimidomethyl)-5'-methylphenyl)benzotriazole, 2,2-methylenebis(4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazo 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-(2-octyloxycarbonylethyl)-phenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3'-(1-methyl-1-phenylethyl)-5'-(1,1,3,3-tetramethylbutyl)-phenyl)benzotriazole, 2-(2H-benzotriazol-2-yl)-6-(linear and side chain dodecyl)-4-methylphenol, a mixture of octyl-3-[3-tert-butyl-4-hydroxy-5-(chloro-2H-benzotriazol-2-yl)phenyl]propionate and 2-ethylhexyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazol-2-yl)phenyl]propionate, etc.), cyanoacrylate-based ultraviolet absorbers (2'-ethylhexyl-2-cyano-3,3-diphenylacrylate, ethyl-2-cyano-3-(3',4'-methylenedioxyphenyl)-acrylate, triazine-based ultraviolet absorbers, etc. may be used, and benzotriazole-based ultraviolet absorbers or triazine-based ultraviolet absorbers that are highly transparent and have an excellent effect of preventing deterioration of the polarizing plate and the transmittance variable layer are preferred, and benzotriazole-based ultraviolet absorbers with a more suitable spectral absorption spectrum are particularly preferred. The benzotriazole-based ultraviolet absorbers may be bis(Bis)-modified, for example, 6,6'-methylenebis(2-(2H-benzo[d][1,2,3]triazol-2-yl)-4-(2,4,4-trimethylpentan-2-yl)phenol), 6,6'-methylenebis(2-(2H-benzo[d][1,2,3]triazol-2-yl)-4-(2-hydroxyethyl)phenol), etc.,

[0136] The hard coating layer is not particularly limited as long as it protects components such as a polarizing plate and a transmittance variable layer from external physical and chemical impacts, and any conventional or later developed hard coating layer may be used.

[0137] In one embodiment, the hard coating layer may be formed by applying a composition for forming a hard coating layer onto another member and curing the composition with light or heat. The composition for forming a hard coating layer is not particularly limited, and may include, for example, a photocurable compound and a photoinitiator.

[0138] The photocurable compound and photoinitiator may be those generally used in the art without any restrictions. For example, the photocurable compound may be a photopolymerizable monomer, a photopolymerizable oligomer, etc., and may have, for example, a monofunctional and / or polyfunctional (meth)acrylate. Examples of the photoinitiator include hydroxycyclohexyl phenyl ketone, trimethylbenzoyldiphenylphosphine oxide, acetophenone-based, and oxime ester-based. Commercially available products include Irgacure-184, TPO, and Irgacure-907.

[0139] <Method of Manufacturing Variable Transmittance Optical Laminate> The variable transmittance optical laminate of the present invention described above can be manufactured by a roll-to-roll process including a step of forming the first transparent conductive layer 200-1 on the transparent substrate 150, a step of forming the second transparent conductive layer 200-2 and the liquid crystal layer 300 on the second polarizer, and a step of bonding the liquid crystal layer 300 and the first transparent conductive layer 200-1.

[0140] That is, the method for producing a variable transmittance optical laminate of the present invention includes the steps of: (a) preparing a first polarizing plate; (b) forming a first transparent conductive layer on a transparent substrate; (c) forming a second transparent conductive layer on a second polarizing plate; (d) coating a liquid crystal layer-forming composition on the second transparent conductive layer to form a liquid crystal layer; (e) bonding the first transparent conductive layer of the laminate formed in step (b) so that it is in contact with the liquid crystal layer of the laminate formed in step (d); and (f) bonding the first polarizing plate prepared in step (a) onto the transparent substrate of the laminate formed in step (e), in which in step (f), the absorption axis of the first polarizing plate and the absorption axis of the second polarizing plate are bonded to each other at right angles in a planar direction, and steps (b) to (e) may be performed by a roll-to-roll process.

[0141] The method for producing a variable transmittance optical laminate of the present invention produces the variable transmittance optical laminate described above, and the contents of the <variable transmittance optical laminate> described above can be applied without any restrictions.

[0142] FIG. 4 is a diagram illustrating a method for manufacturing a variable transmittance optical laminate according to an embodiment of the present invention.

[0143] Referring to FIG. 4, the second polarizer 100-2 having the second transparent conductive layer 200-2 formed thereon and the transparent substrate 150 having the first transparent conductive layer 200-1 formed thereon may be continuously processed by a roll-to-roll process on different lines, or may be continuously processed in a direction in which the two lines meet and can be joined to each other.

[0144] Hereinafter, the method for producing a variable transmittance optical laminate of the present invention will be described step by step. (a) preparing a first polarizing plate; First, the first polarizing plate 100-1 is prepared so that it can be used in step (f).

[0145] An adhesive layer may be formed on the first polarizer 100-1 and then attached onto the transparent substrate 150. In this case, the process of forming the adhesive layer on the first polarizer 100-1 may be performed by a roll-to-roll process.

[0146] The first polarizing plate 100-1 and the adhesive layer may be similarly applied to the polarizing plate 100 and the adhesive layer 400 described in the <variable transmittance optical laminate>.

[0147] Thereafter, the polarizing plate 100 is cut and prepared so that it can be bonded to the second polarizing plate 100-2 so that the absorption axis of the polarizing plate 100-2 is perpendicular to the absorption axis of the second polarizing plate 100-2 in the planar direction.

[0148] (b) forming a first transparent conductive layer on a transparent substrate; The first transparent conductive layer 200-1 is formed on a transparent substrate 150, which can be manufactured by a roll-to-roll process.

[0149] The first transparent conductive layer 200-1 may be formed by deposition or coating on one side of the transparent substrate 150. In this case, in order to improve adhesion, the first transparent conductive layer 200-1 may be formed after performing a pretreatment such as a corona treatment or a plasma treatment on one side of the transparent substrate 150.

[0150] Alternatively, an easy-adhesion layer (not shown) may be provided on one surface of the transparent substrate 150, and the first transparent conductive layer 200-1 may be attached thereto.

[0151] The first transparent conductive layer 200-1, the transparent substrate 150 and the adhesive layer can be similarly applied to the transparent conductive layer 200, the transparent substrate 150 and the adhesive layer 400 described in the <variable transmittance optical laminate>.

[0152] (c) forming a second transparent conductive layer on the second polarizer; A second polarizing plate 100-2 is prepared, and a second transparent conductive layer 200-2 is formed by a roll-to-roll process.

[0153] The second transparent conductive layer 200-2 may be formed by being directly coated on one side of the second polarizer 100-2. In this case, in order to improve adhesion, a pretreatment such as a corona treatment or a plasma treatment may be performed on one side of the second polarizer 100-2, and then the transparent conductive layer 200-2 may be formed by directly contacting the one side of the second polarizer 100-2.

[0154] Alternatively, an easy-adhesion layer (not shown) may be provided on one surface of the second polarizer 100-2, and the second transparent conductive layer 200-2 may be attached thereto.

[0155] The second polarizing plate 100-2, the second transparent conductive layer 200-2 and the easy-adhesion layer can be similarly applied to the polarizing plate 100, the transparent conductive layer 200 and the adhesive layer 400 described in the <variable transmittance optical laminate>.

[0156] After the step (c), a certain groove is formed on the surface of the second transparent conductive layer 200-2 while passing through an alignment forming unit 250 by a roll-to-roll process, thereby performing rubbing alignment.

[0157] The second transparent conductive layer 200-2 includes a conductive polymer, which, unlike transparent conductive layers that include metal components, can form certain grooves on the surface, thereby aligning the liquid crystal compounds in the liquid crystal layer in the desired position and direction.

[0158] Since the second transparent conductive layer 200-2 is rubbed in the MD direction by the roll-to-roll continuous process, it is aligned at a certain angle, and the alignment angle of the second transparent conductive layer 200-2 can be formed similarly to the absorption axis of the second polarizer 100-2. For example, the absorption axis of the second polarizer 100-2 may be 0°, and the alignment angle formed in the second transparent conductive layer 200-2 may be 0°.

[0159] (d) forming a liquid crystal layer by coating a liquid crystal layer-forming composition on the second transparent conductive layer; As described above, the liquid crystal layer 300 included in the variable transmittance optical laminate of the present invention includes the polymer network 310 together with the liquid crystal compound 320, and thus can properly maintain the cell gap of the liquid crystal layer without including a separate sealant and / or spacer, and the description of the liquid crystal layer 300 described in the <Variable Transmittance Optical Laminate> above is applicable without any limitations.

[0160] The liquid crystal layer 300 may be formed by applying a liquid crystal layer forming composition including a polymerizable monomer and a liquid crystal compound onto the rubbed second transparent conductive layer 200-2 while passing through a liquid crystal layer forming unit 350 in a continuous roll-to-roll process after step (c) and curing the composition (not shown).

[0161] (e) a step of bonding the first transparent conductive layer of the laminate formed in the step (b) to the liquid crystal layer of the laminate formed in the step (d) so as to be in contact with each other. The first transparent conductive layer 200-1 of the laminate formed in the step (b) is bonded to the liquid crystal layer 300 formed in the step (d) so as to be in contact with the liquid crystal layer 300-1.

[0162] At this time, the laminate formed in step (b) and the laminate having the liquid crystal layer 300 formed in step (d) are transferred through different rails, and the first transparent conductive layer 200-1 and the liquid crystal layer 300 may be bonded to each other through a roll-to-roll process.

[0163] (f) bonding the first polarizing plate prepared in the step (a) onto the transparent substrate of the laminate formed in the step (e); After the step (e), the first polarizing plate 100-1 prepared in the step (a) is laminated with the second polarizing plate 100-2 such that their absorption axes are perpendicular to each other.

[0164] That is, the second polarizer 100-2, the second transparent conductive layer 200-2, the liquid crystal layer 300, the first transparent conductive layer 200-1 and the transparent substrate 150 are sequentially laminated by a roll-to-roll process, and then the first polarizer 100-1 and the absorption axis of the second polarizer 100-2 are laminated in a mutually perpendicular direction in the planar direction, thereby manufacturing the variable transmittance optical laminate of the present invention.

[0165] For example, the absorption axis of the second polarizer 100-2 may be 0°, and the absorption axis of the first polarizer 100-1 may be 90°.

[0166] In this case, the absorption axes of the first polarizer 100-1 and the second polarizer 100-2 are arranged perpendicular to each other in the planar direction, which may be advantageous in improving the transmittance variable range between the light-transmitting mode (ON) and the light-blocking mode (OFF) of the optical laminate by driving the liquid crystal.

[0167] In this manner, the liquid crystal layer is formed through a roll-to-roll continuous process to manufacture the variable transmittance optical laminate, so that the process is continuous and the manufacturing can be carried out economically.

[0168] <Smart windows, automotive and building fixtures> The present invention includes the variable transmittance optical laminate, as well as a smart window including the same. The present invention also includes an automobile in which the smart window is applied to at least one of a front window, a rear window, a side window, a sunroof window, and an interior partition, and a building fixture including the smart window.

Claims

1. A first polarizing plate; A transparent substrate bonded onto one surface of the first polarizing plate; A first transparent conductive layer formed on the transparent substrate; a second polarizing plate facing the first polarizing plate; a second transparent conductive layer formed on one surface of the second polarizing plate and facing the first transparent conductive layer; a liquid crystal layer provided between the first transparent conductive layer and the second transparent conductive layer, the second transparent conductive layer includes a conductive polymer, the liquid crystal layer comprises a polymer network and a liquid crystal compound; The liquid crystal compounds are aligned with a uniform initial orientation.

2. 2. The variable transmittance optical laminate according to claim 1, wherein the liquid crystal behavior mode of the liquid crystal layer is any one selected from the group consisting of a twisted nematic (TN) mode, a super twisted nematic (STN) mode, an in-plane switching (IPS) mode, a fringe-field switching (FFS) mode, and a vertical alignment (VA) mode.

3. The variable transmittance optical laminate according to claim 2 , wherein the liquid crystal behavior mode of the liquid crystal layer is a twisted nematic (TN) mode.

4. The variable transmittance optical laminate according to claim 1 , wherein the liquid crystal layer comprises a cured product of a liquid crystal layer-forming composition comprising a polymerizable monomer and a liquid crystal compound.

5. The variable transmittance optical laminate according to claim 4 , wherein the liquid crystal layer forming composition contains 10 to 30% by weight of a polymerizable monomer based on the total weight of the composition.

6. The variable transmittance optical laminate according to claim 1 , wherein the second transparent conductive layer has a surface that contacts the liquid crystal layer and is oriented by rubbing.

7. The conductive polymer may be polythiophene, poly(3,4-ethylenedioxythiophene), polyaniline, polyacetylene, polydiacetylene, polyphenylene, polyphenylenevinylene, polyphenylene sulfide, polythienylenevinylene, polythiophenevinylene, polyfluorene, polypyrrole, poly(3,4-ethylenedioxythiophene):polystyrenesulfonate, poly(3,4-ethylenedioxythiophene):camphorsulfonic acid, poly(3,4-ethylenedioxythiophene):toluene ...

2. The variable transmittance optical laminate of claim 1, comprising at least one selected from the group consisting of polythiophene: dodecylbenzenesulfonic acid, polyaniline: polystyrene sulfonate, polyaniline: camphorsulfonic acid, polypyrrole: polystyrene sulfonate, polypyrrole: camphorsulfonic acid, polypyrrole: toluenesulfonic acid, polypyrrole: dodecylbenzenesulfonic acid, polythiophene: polystyrene sulfonate, polythiophene: camphorsulfonic acid, polythiophene: toluenesulfonic acid, and polythiophene: dodecylbenzenesulfonic acid.

8. The variable transmittance optical laminate of claim 1 , wherein the second transparent conductive layer is in direct contact with the second polarizer without a separate substrate between the second transparent conductive layer and the second polarizer.

9. The variable transmittance optical laminate according to claim 1 , wherein the second transparent conductive layer includes an easy-adhesion layer between the second polarizing plate and the second transparent conductive layer, and is formed in direct contact with the second polarizing plate.

10. 2. The variable transmittance optical laminate according to claim 1, wherein at least one of the first polarizing plate and the second polarizing plate includes one or more functional layers selected from the group consisting of a protective layer, a phase difference adjusting layer, and a refractive index adjusting layer.

11. The variable transmittance optical laminate according to claim 1 , wherein the first polarizing plate and the second polarizing plate have a thickness of 30 μm to 200 μm.

12. The variable transmittance optical laminate according to claim 1 , further comprising at least one layer selected from the group consisting of an adhesive layer, an ultraviolet absorbing layer, and a hard coating layer.

13. (a) providing a first polarizer; (b) forming a first transparent conductive layer on a transparent substrate; (c) forming a second transparent conductive layer on the second polarizer; (d) coating a liquid crystal layer-forming composition on the second transparent conductive layer to form a liquid crystal layer; (e) bonding the first transparent conductive layer of the laminate formed in the step (b) to the liquid crystal layer of the laminate formed in the step (d) so as to be in contact with each other; (f) bonding the first polarizing plate prepared in the step (a) onto the transparent substrate of the laminate formed in the step (e); In the step (f), the first polarizing plate and the second polarizing plate are bonded together so that their absorption axes are perpendicular to each other in a planar direction; The method for producing a variable transmittance optical laminate, wherein the steps (b) to (e) are performed in a roll-to-roll process.

14. The method for producing a variable transmittance optical laminate according to claim 13 , wherein the second transparent conductive layer includes a conductive polymer.

15. The method for producing a variable transmittance optical laminate according to claim 13, further comprising the step of forming a rubbing alignment on a surface of the second transparent conductive layer in contact with the liquid crystal layer between the steps (c) and (d).

16. The method for manufacturing a variable transmittance optical laminate according to claim 13, wherein in step (c), the second transparent conductive layer is formed in direct contact with the second polarizer without using a separate substrate between the second transparent conductive layer and the second polarizer.

17. The method for producing a variable transmittance optical laminate according to claim 13 , wherein in step (c), the second transparent conductive layer includes an easy-adhesion layer between the second polarizer and the second transparent conductive layer, and is formed in direct contact with the second polarizer.

18. 14. The method for manufacturing a variable transmittance optical laminate according to claim 13, wherein the liquid crystal behavior mode of the liquid crystal layer is any one selected from the group consisting of a twisted nematic (TN) mode, a super twisted nematic (STN) mode, an in-plane switching (IPS) mode, a fringe-field switching (FFS) mode, and a vertical alignment (VA) mode.

19. The method for manufacturing a variable transmittance optical laminate according to claim 18, wherein the liquid crystal behavior mode of the liquid crystal layer is a twisted nematic (TN) mode.

20. The method for producing a variable transmittance optical laminate according to claim 13, wherein the liquid crystal layer comprises a cured product of a liquid crystal layer-forming composition that contains a polymerizable monomer and a liquid crystal compound.

21. The method for producing a variable transmittance optical laminate according to claim 13 , wherein the liquid crystal layer comprises a polymer network and a liquid crystal compound.

22. A smart window comprising the variable transmittance optical stack according to any one of claims 1 to 12.

23. 23. A car comprising the smart window of claim 22 applied to at least one of a front window, a rear window, a side window, a sunroof window, and an interior partition.

24. 23. A building fixture comprising the smart window of claim 22.

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