Optical laminate, method for manufacturing the same, smart window comprising the same, and window for automobile

Abstract

The present invention provides a variable transmittance optical laminate, a method for manufacturing the same, a smart window including the same, and a window for an automobile or a building using the same. The variable transmittance optical laminate includes: a first polarizing plate; a transparent substrate laminated on 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, in which the second transparent conductive layer contains a conductive polymer, the liquid crystal layer contains a polymer network and liquid crystal compounds, and the liquid crystal compounds are arranged in a uniform initial orientation.

Description

Technical Field

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

[0002] Generally, an external light blocking coating is often applied to the glass window of a moving vehicle or the like. However, the transmittance of the glass window of a conventional moving vehicle is fixed, and the transmittance of the external light blocking coating is also fixed. Therefore, since the overall transmittance of the window of such a conventional moving vehicle is fixed, accidents may occur. For example, if the overall transmittance is set low, there is no problem during the day when the surrounding light is sufficient. However, in situations such as at night when the surrounding light is insufficient, there is a problem that it is difficult for a driver or the like to correctly view the surroundings of the moving vehicle. In addition, if the overall transmittance is set high, there is a problem that glare may occur to a driver or the like during the day when the surrounding light is sufficient. For this reason, a variable transmittance optical laminate that can change the light transmittance when a voltage is applied has been developed.

[0003] The above variable transmittance optical laminate is driven by applying a voltage to drive the liquid crystal to change the transmittance. To date, the developed variable transmittance optical laminate is made by providing spacers in the liquid crystal layer to maintain the cell gap of the liquid crystal layer.

[0004] For example, Japanese Patent Laid-Open No. 2018-010035 also discloses a variable transmittance optical laminate that uses a liquid crystal layer including columnar spacers or spherical spacers to maintain a predetermined cell gap.

[0005] However, when columnar spacers are included in the liquid crystal layer in this way, the manufacturing process becomes cumbersome, resulting in an increase in manufacturing cost, and there is a problem that the alignment film is damaged and the transmittance changes during the process of irradiating ultraviolet rays to the photoresist to form the spacers. In addition, when spherical spacers are used to maintain the cell gap of the liquid crystal layer, there are problems such as an inability to maintain a firm cell gap and difficulty in maintaining a constant optical color in the plane, and current short-circuit of the optical laminate.

[0006] In addition, in the above variable transmittance optical laminate, various optical members can be laminated in several layers in order to protect the lamination surface, provide a lamination surface with other members, polarization functions, etc. In addition, it can be manufactured by various manufacturing methods, but from the aspect of process economy, continuous production is preferably carried out by a roll-to-roll (R2R) process including a lamination process.

[0007] However, the transmissivity-variable optical laminate is driven by applying a voltage to drive the liquid crystal to vary the transmissivity, and in order to vary the transmissivity, it has a liquid crystal layer whose phase changes with the applied electric field to achieve the target transmissivity. For this purpose, in order to laminate the absorption axes of the two polarizing plates orthogonally, one of the polarizing plates must be rotated 90° after cutting the polarizing plate and then laminated, so this makes it difficult to apply the roll-to-roll process.

[0008] Thus, when manufacturing a transmissivity-variable optical laminate with the absorption axes of the two polarizing plates orthogonal, each laminate is made into a separate sheet. After cutting each sheet, a liquid crystal layer is formed on any one of the sheets, and in order for the transmissivity to change when a voltage is applied, the transmission axes of each sheet are orthogonally laminated for manufacturing. Therefore, there is a problem that the manufacturing process becomes complicated and it is difficult to reduce costs.

[0009] Therefore, in reality, it is necessary to develop a transmissivity-variable optical laminate and a manufacturing method that can maintain a firm cell gap even without using spacers in the liquid crystal layer and can apply the roll-to-roll process when forming the liquid crystal layer, thereby simplifying the manufacturing process.

[0010] Prior Art Documents

[0011] Patent Documents

[0012] Patent Document 1: Japanese Laid-Open Patent No. 2018-010035 Summary of the Invention

[0013] Problems to be Solved

[0014] An object of the present invention is to provide a transmissivity-variable optical laminate including a liquid crystal layer having a polymer network, thereby being able to prevent problems such as damage to the alignment film caused by using spacers or difficulty in maintaining a constant in-plane optical color.

[0015] In addition, an object of the present invention is to provide a transmissivity-variable optical laminate including a liquid crystal layer containing a polymer network and a liquid crystal compound arranged in a uniform initial alignment, thereby being able to adjust the transmissivity of the incident light.

[0016] In addition, an object of the present invention is to provide a transmissivity-variable optical laminate that does not include a separate substrate for forming a conductive layer and a separate alignment film for the initial alignment of the liquid crystal compound, thereby simplifying the manufacturing process.

[0017] In addition, an object of the present invention is to provide a transmissivity-variable optical laminate that does not include a separate alignment film for the initial alignment of the liquid crystal compound, thereby significantly reducing the thickness.

[0018] In addition, an object of the present invention is to provide a method for manufacturing a variable transmittance optical laminate, which can apply a roll-to-roll continuous process in the formation of a liquid crystal layer when manufacturing the variable transmittance optical laminate, thereby having excellent productivity and economy.

[0019] In addition, an object of the present invention is to provide an intelligent window including the above variable transmittance optical laminate and a window for an automobile or a building using the above intelligent window.

[0020] However, the problems to be solved by the present invention are not limited to the above-mentioned problems, and those of ordinary skill in the art should be able to understand other problems not mentioned based on the following description.

[0021] Method for solving the problems

[0022] The present invention relates to a variable transmittance optical laminate, which includes: a first polarizing plate; a transparent substrate laminated on one surface of the first polarizing plate; a first transparent conductive layer formed on the transparent substrate; a second polarizing plate opposite to the first polarizing plate; a second transparent conductive layer formed on one surface of the second polarizing plate and opposite to the first transparent conductive layer; and a liquid crystal layer disposed 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 in a uniform initial orientation.

[0023] 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 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.

[0024] In a second aspect of the present invention, the liquid crystal behavior mode of the liquid crystal layer may be a twisted nematic (TN) mode.

[0025] In a third aspect of the present invention, the liquid crystal layer may include a cured product of a liquid crystal layer-forming composition containing a polymerizable monomer and a liquid crystal compound.

[0026] 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 relative to the total weight of the composition.

[0027] In the fifth aspect of the present invention, the surface of the second transparent conductive layer that contacts the liquid crystal layer can be rubbed for alignment.

[0028] In the sixth aspect of the present invention, the above-mentioned conductive polymer may include one or more selected from the group consisting of polythiophene, poly(3,4-ethylenedioxythiophene), polyaniline, polyacetylene, polydiacetylene, polyphenylene, polyphenylene vinylene, polyphenylene sulfide, polythienylene vinylene, polythiophene vinylene, polyfluorene, polypyrrole, poly(3,4-ethylenedioxythiophene):polystyrenesulfonate, poly(3,4-ethylenedioxythiophene):camphorsulfonic acid, poly(3,4-ethylenedioxythiophene):toluenesulfonic acid, poly(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.

[0029] In the seventh aspect of the present invention, the second transparent conductive layer can be formed to be in direct contact with the second polarizing plate without including a separate substrate therebetween.

[0030] In the eighth aspect of the present invention, the second transparent conductive layer can be formed to be in direct contact with the second polarizing plate through an inclusion of an easy-bonding layer therebetween.

[0031] In the 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 retardation adjusting layer, and a refractive index adjusting layer.

[0032] In the 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.

[0033] In the eleventh aspect of the present invention, the transmissivity variable optical laminate may further include one or more selected from the group consisting of an adhesion / bonding layer, an ultraviolet absorption layer, and a hard coat.

[0034] In addition, the present invention relates to a method for manufacturing a variable transmittance optical laminate, which includes: (a) a step of preparing a first polarizing plate; (b) a step of forming a first transparent conductive layer on a transparent substrate; (c) a step of forming a second transparent conductive layer on a second polarizing plate; (d) a step of forming a liquid crystal layer by coating a liquid crystal layer forming composition on the second transparent conductive layer; (e) a step of laminating in such a manner that the first transparent conductive layer of the laminate formed in the above step (b) is in contact with the liquid crystal layer of the laminate formed in the above step (d); and (f) a step of laminating the first polarizing plate prepared in the above step (a) on the transparent substrate of the laminate formed in the above step (e), wherein in the above step (f), the absorption axes of the first polarizing plate and the second polarizing plate are laminated in a manner orthogonal to each other in the top view direction, and the above steps (b) to (e) are carried out by a roll-to-roll process.

[0035] In the twelfth aspect of the present invention, the second transparent conductive layer may contain a conductive polymer.

[0036] In the thirteenth aspect of the present invention, between the above steps (c) and (d), a step of forming a rubbing orientation on the surface of the second transparent conductive layer in contact with the liquid crystal layer may further be included.

[0037] In the fourteenth aspect of the present invention, in the above step (c), the second transparent conductive layer may be formed to be in direct contact with the second polarizing plate without including a separate substrate therebetween.

[0038] In the fifteenth aspect of the present invention, in the above step (c), the second transparent conductive layer may be formed to be in direct contact with the second polarizing plate through an inclusion of an easy adhesion layer therebetween.

[0039] In the sixteenth aspect of the present invention, the liquid crystal behavior mode of the above liquid crystal layer may be 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.

[0040] In the seventeenth aspect of the present invention, the liquid crystal behavior mode of the above liquid crystal layer may be a twisted nematic (TN) mode.

[0041] In the eighteenth aspect of the present invention, the above liquid crystal layer may contain a cured product of a liquid crystal layer forming composition containing a polymerizable monomer and a liquid crystal compound.

[0042] In the nineteenth aspect of the present invention, the liquid crystal layer may include a polymer network and a liquid crystal compound.

[0043] In addition, the present invention relates to a smart window including the above-described variable transmittance optical laminate.

[0044] In addition, the present invention relates to an automobile in which the above-described smart window is applied to at least one of a front window, a rear window, a side window, a sunroof, and an interior partition.

[0045] In addition, the present invention relates to a building window including the above-described smart window.

[0046] Advantages of the Invention

[0047] According to the variable transmittance optical laminate of the present invention, by including a liquid crystal layer containing a polymer network, it is possible to prevent problems such as damage to the alignment film caused by the use of spacers in the past or difficulty in maintaining a constant in-plane optical color. Thus, compared with conventional optical laminates, the driving stability can be improved.

[0048] In addition, according to the variable transmittance optical laminate of the present invention, although a polymer network is formed in the liquid crystal layer, the liquid crystal compounds can be arranged in a state of maintaining a uniform initial alignment, and thus the transmittance of light incident on the optical laminate can be adjusted.

[0049] In addition, according to the variable transmittance optical laminate of the present invention, the conductive layer containing a conductive polymer substance can simultaneously function as an electrode for driving the liquid crystal layer and an alignment film, and thus a separate alignment film forming process can be omitted. Compared with conventional optical laminates, the manufacturing process can be simplified.

[0050] In addition, according to the variable transmittance optical laminate of the present invention, the conductive layer containing a conductive polymer substance can simultaneously function as an electrode for driving the liquid crystal layer and an alignment film, and thus does not include a separate alignment film for the initial alignment of the liquid crystal compounds. Thus, compared with conventional optical laminates, the thickness can be significantly reduced.

[0051] According to the manufacturing method of the variable transmittance optical laminate of the present invention, a roll-to-roll continuous process can be applied in the formation of the liquid crystal layer, and thus, when manufacturing the variable transmittance optical laminate, there are excellent effects in terms of productivity and economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 FIG. is a diagram showing the laminate structure of a variable transmittance optical laminate according to an embodiment of the present invention.

[0053] Figures 2a to 2eIt is a diagram showing the laminated structure of a polarizing plate according to one or more embodiments of the present invention.

[0054] Figure 3 It is a diagram showing the laminated structure of a variable transmittance optical laminate according to other embodiments of the present invention.

[0055] Figure 4 It is a diagram schematically showing a method for manufacturing a variable transmittance optical laminate according to one embodiment of the present invention. Detailed Description

[0056] The present invention relates to a variable transmittance optical laminate including a liquid crystal layer containing a polymer network and a liquid crystal compound arranged in a uniform initial orientation. Specifically, the present invention relates to a variable transmittance optical laminate capable of maintaining the cell gap of the liquid crystal layer through the polymer network in the liquid crystal layer, thereby preventing problems caused by the use of a sealant and spacers in the past, and capable of adjusting the transmittance of light incident on the optical laminate because the liquid crystal compound is arranged in a uniform initial orientation.

[0057] More specifically, the present invention relates to a variable transmittance optical laminate including: a first polarizing plate; a transparent substrate laminated on one surface of the first polarizing plate; a first transparent conductive layer formed on the transparent substrate; a second polarizing plate opposed to the first polarizing plate; a second transparent conductive layer formed on one surface of the second polarizing plate and opposed to the first transparent conductive layer; and a liquid crystal layer disposed between the first transparent conductive layer and the second transparent conductive layer, wherein the second transparent conductive layer contains a conductive polymer, the liquid crystal layer contains a polymer network and a liquid crystal compound, and the liquid crystal compound is arranged in a uniform initial orientation.

[0058] In addition, the present invention relates to a method for manufacturing a variable transmittance optical laminate, which has excellent productivity and economy because the variable transmittance optical laminate is manufactured by a roll-to-roll continuous process.

[0059] More specifically, the present invention relates to a method for manufacturing a variable transmittance optical laminate, which includes: (a) a step of preparing a first polarizing plate; (b) a step of forming a first transparent conductive layer on a transparent substrate; (c) a step of forming a second transparent conductive layer on a second polarizing plate; (d) a step of forming a liquid crystal layer by coating a liquid crystal layer-forming composition on the second transparent conductive layer; (e) a step of laminating in such a manner that the first transparent conductive layer of the laminate formed in the step (b) is in contact with the liquid crystal layer of the laminate formed in the step (d); and (f) a step of laminating the first polarizing plate prepared in the step (a) on the transparent substrate of the laminate formed in the step (e), wherein in the step (f), the absorption axes of the first polarizing plate and the second polarizing plate are laminated in a direction perpendicular to each other in a plan view, and the steps (b) to (e) are carried out by a roll-to-roll process.

[0060] The variable transmittance optical laminate of the present invention is particularly suitable for the technical field capable of changing the light transmittance according to the application of voltage. For example, it can be used for smart windows and the like.

[0061] A so-called smart window refers to an optical structure that changes the light transmittance according to the application of an electric signal to control the amount of light or heat passing through. That is, a smart window can change into a transparent, opaque, or semi-transparent state according to voltage, and is also called a variable transmittance glass, a dimming glass, or a smart glass, etc.

[0062] A smart window can be used as a partition for dividing the interior space of a vehicle or a building or a partition for privacy protection, or as a daylighting window disposed at an opening of a building, and can also be used as a highway road sign, a billboard, a scoreboard, a clock, or an advertising screen, and can be used instead of the glass of a transportation tool such as a window or a skylight of an automobile, a bus, an airplane, a ship, or a train.

[0063] The variable transmittance optical laminate of the present invention can also be used as a smart window in the above technical fields. However, since the conductive layer is directly formed on the polarizing plate and does not include a separate substrate for forming the conductive layer, the thickness is thin, which is beneficial to the bending characteristics, and it is particularly suitable for use in vehicle or building smart windows. In one or more embodiments, the smart window applying the variable transmittance optical laminate of the present invention can be used for the front window, rear window, side window, and skylight of an automobile, or a building window, etc. In addition to the use of blocking external light, it can also be used for the internal space partitioning use or privacy protection use of an automobile or a building, such as an internal partition.

[0064] Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, the following drawings attached to this specification are only illustrative of the preferred embodiments of the present invention, and serve to further understand the above-described invention content together with the technical idea of the present invention. Therefore, the present invention should not be construed as being limited only to the matters described in these drawings.

[0065] The terms used in this specification are intended to describe the embodiments and are not intended to limit the present invention. In this specification, unless otherwise specifically mentioned in the context, the singular form also includes the plural form. For example, the "polarizing plate" used in this specification may refer to at least one of the first polarizing plate and the second polarizing plate, and the "transparent conductive layer" may refer to at least one of the first transparent conductive layer and the second transparent conductive layer.

[0066] The terms "comprises" and / or "comprising" used in this specification are used in the sense of not excluding the existence or addition of one or more other elements, steps, actions, and / or components other than the recited elements, steps, actions, and / or components. Throughout the specification, the same reference numerals refer to the same components.

[0067] As illustrated in the drawings, spatially relative terms such as "below", "bottom surface", "lower part", "above", "upper surface", "upper part", etc. may be used to easily describe the relative relationship between one element or component and other elements or components. Spatially relative terms should be understood as terms including directions different from each other when the elements are in use or operation, in addition to the directions illustrated in the drawings. For example, when the element illustrated in the drawings is flipped, the element described as "below" or "lower part" of other elements may be placed "above" other elements. Therefore, the exemplary term "below" may include both the below and above directions. The element may also be oriented in other directions, so spatially relative terms may be interpreted according to the orientation.

[0068] The "top view direction" used in this specification may be interpreted as a direction orthogonal to the polarizing plate and / or the transparent conductive layer, that is, the direction observed from the visible side of the user.

[0069] <Variable transmittance optical laminate>

[0070] Figure 1 is a diagram showing the laminated structure of a variable transmittance optical laminate according to an embodiment of the present invention, Figures 2a to 2e is a diagram showing the laminated structure of a polarizing plate according to one or more embodiments of the present invention, Figure 3This is a diagram showing the laminated structure of a variable transmittance optical laminate according to another embodiment of the present invention.

[0071] Referring Figure 1 , a variable transmittance optical laminate according to an embodiment of the present invention may include a first polarizing plate 100-1, a second polarizing plate 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.

[0072] Referring to FIG. 2, the polarizing plate 100 may include a polarizer 110, and may further include functional layers such as a protective layer 120, a retardation adjusting layer 130, and a refractive index adjusting layer 140 on one or both surfaces of the polarizer 110. For example, the polarizing plate 100 may include a polarizer 110 and a protective layer 120 laminated on one or both surfaces of the polarizer 110 (refer to Figure 2a and Figure 2b ), may include a polarizer 110, a protective layer 120 laminated on one surface of the polarizer 110, and a retardation adjusting layer 130 laminated on the other surface of the polarizer 110 opposite to the one surface (refer to Figure 2c ), may include a polarizer 110, a protective layer 120 laminated on one surface of the polarizer, and a retardation adjusting layer 130 and a refractive index adjusting layer 140 laminated in sequence on the other surface of the polarizer opposite to the one surface (refer to Figure 2d ), may include a polarizer 110, a protective layer 120 laminated on one surface of the polarizer, and a protective layer 120 and a retardation adjusting layer 130 laminated in sequence on the other surface of the polarizer opposite to the one surface (refer to Figure 2e ).

[0073] The polarizer 110 may use a conventional or future-developed polarizer. For example, a stretched polarizer or a coated polarizer may be used.

[0074] 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. As the polyvinyl acetate - based resin, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate, copolymers of vinyl acetate and other monomers capable of copolymerizing with it may also be mentioned. As the other monomers, they may be unsaturated carboxylic acid - based, unsaturated sulfonic acid - based, olefin - based, vinyl ether - based, acrylamide - based monomers having an ammonium group, etc. In addition, the polyvinyl alcohol (PVA) - based resin includes modified substances. For example, it may also be polyvinyl formal or polyvinyl acetal modified by aldehydes.

[0075] In one embodiment, the above-mentioned coating type polarizer can be formed using a liquid crystal coating composition. At this time, the liquid crystal coating composition may include a reactive liquid crystal compound, a dichroic dye, and the like.

[0076] The above-mentioned reactive liquid crystal compound may refer to a compound that includes a mesogen skeleton and the like and contains one or more polymerizable functional groups. Such a reactive liquid crystal compound has been widely known under the name of so-called reactive mesogen (RM). The above-mentioned 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.

[0077] The above-mentioned reactive liquid crystal compound can be a monofunctional or polyfunctional reactive liquid crystal compound. The above-mentioned monofunctional reactive liquid crystal compound may refer to a compound having 1 polymerizable functional group, and the polyfunctional reactive liquid crystal compound may refer to a compound containing 2 or more polymerizable functional groups.

[0078] The above-mentioned dichroic dye is a component added to the liquid crystal coating composition to impart polarization characteristics, and has the property that the absorbance in the long axis direction of the molecule is different from the absorbance in the short axis direction. The above-mentioned dichroic dye can use dichroic dyes developed in the past or in the future. For example, it may include one or more selected from the group consisting of azo dyes, anthraquinone dyes, perylene dyes, merocyanine dyes, azomethine dyes, phthaloperylene dyes, indigo dyes, dioxadine dyes, polythiophene dyes, and phenoxazine dyes.

[0079] The above-mentioned liquid crystal coating composition may further include a solvent capable of dissolving the above-mentioned reactive liquid crystal compound and the above-mentioned dichroic dye. For example, propylene glycol monomethyl ether acetate (PGMEA), methyl ethyl ketone (MEK), xylene, chloroform, etc. can be used. In addition, the above-mentioned liquid crystal coating composition may further include a leveling agent, a polymerization initiator, etc. within a range that does not hinder the polarization characteristics of the coating film.

[0080] The above-mentioned protective layer 120 is intended to protect the polarization characteristics of the polarizer 110 from the influence of post-processes and the external environment, and can be realized in the form of a protective film or the like.

[0081] As Figure 2a and Figure 2b shown in the figures, the above-mentioned protective layer 120 can be formed by directly contacting one or both sides of the polarizer 110, but is not limited thereto. For example, the above-mentioned protective layer can also be used in a multilayer structure formed by laminating one or more protective layers continuously, and can be formed by directly contacting other functional layers.

[0082] In one or more embodiments, the above-mentioned 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, 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).

[0083] The above-mentioned retardation adjustment layer 130 is intended to supplement the optical properties of the optical laminate, and can be realized in the form of a retardation film or the like, and a retardation film or the like developed in the past or in the future can be used. 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 can be used, and they can be used alone or in combination.

[0084] As Figure 2c and Figure 2d shown in the figures, the above-mentioned retardation adjustment layer 130 can be formed by directly contacting one side of the polarizer 110, but is not limited thereto. For example, as Figure 2e shown in the figures, the above-mentioned retardation adjustment layer 130 can be formed on one side of the protective layer 120 so that the polarizer 110, the protective layer 120, and the retardation adjustment layer 130 are laminated in sequence.

[0085] The above-mentioned phase difference adjusting layer 130 can use a polymer stretched film or a liquid crystal polymer film obtained by stretching a polymer film capable of imparting optical anisotropy in an appropriate manner by stretching.

[0086] In one embodiment, the above-mentioned polymer stretched film can use a polymer layer containing the following substances: polyolefins such as polyethylene (PE) or polypropylene (PP), cyclic olefin polymers (COP) such as polynorbornene, polyvinyl chloride (PVC), polyacrylonitrile (PAN), polysulfone (PSU), acrylic resin, polycarbonate (PC), polyesters such as polyethylene terephthalate (PET), polyacrylate, cellulose ester-based polymers such as polyvinyl acholol (PVA) or triacetyl cellulose (TAC), or copolymers of two or more of the above monomers forming the polymers, etc.

[0087] The method for obtaining the above-mentioned polymer stretched film is not particularly limited. For example, it can be obtained by stretching after forming the above-mentioned polymer material into a film shape. The method for forming into a film shape is not particularly limited, and it can be formed into a film by known methods such as injection molding, sheet molding, blow molding, injection blow molding, inflation molding, extrusion molding, foam molding, casting molding, or can be formed by secondary processing molding methods such as compression molding and vacuum molding. Among them, extrusion molding and casting molding are preferably used. At this time, for example, an extruder equipped with a T-die, a circular die, etc. can be used to extrude and mold the unstretched film. In the case of obtaining a molded product by extrusion molding, a material in which various resin components, additives, etc. have been melt-kneaded in advance can be used, or molding can be performed via melt-kneading during extrusion molding. In addition, a solvent common to various resin components, such as chloroform, dichloromethane, etc., can be used to dissolve various resin components, and then casting drying and curing can be performed to cast-mold the unstretched film.

[0088] For the above-mentioned polymer stretched film, the formed film can be uniaxially stretched in the machine direction (MD; Mechanical Direction, longitudinal or length direction), uniaxially stretched in the direction perpendicular to the machine direction (TD; Transverse Direction, transverse or width direction), or can be stretched to produce a biaxially stretched film by sequential biaxial stretching methods such as roll stretching and tenter stretching, simultaneous biaxial stretching methods based on tenter stretching, and biaxial stretching methods based on tubular stretching.

[0089] The above-mentioned liquid crystal polymer film may contain a reactive liquid crystal compound in a polymerized state. The above-mentioned reactive liquid crystal compound can be equally applicable to the content of the reactive liquid crystal compound for the above-mentioned coating type polarizer.

[0090] In one or more embodiments, for the thickness of the above-mentioned retardation adjustment layer 130, in the case of a polymer stretched film, it can be 10 μm to 100 μm, and in the case of a liquid crystal polymer film, it can be 0.1 μm to 5 μm.

[0091] The above-mentioned refractive index adjustment layer 140 is provided to compensate for the refractive index difference of the optical laminate caused by the above-mentioned transparent conductive layer 200, and can play a role in improving visible characteristics, etc. by reducing the refractive index difference. In addition, the above-mentioned refractive index adjustment layer 140 can also be provided to correct the color caused by the above-mentioned transparent conductive layer 200. On the other hand, in the case where the above-mentioned transparent conductive layer has a pattern, through the above-mentioned refractive index adjustment layer 140, it is possible to compensate for the transmittance difference between the patterned area where the pattern is formed and the non-patterned area where no pattern is formed.

[0092] Specifically, the above-mentioned transparent conductive layer 200 is adjacent and laminated to other members having a different refractive index (for example, the polarizer 110, etc.). Due to the refractive index difference from the adjacent other layers, a difference in light transmittance will be induced. Especially when the transparent conductive layer has a pattern, there may be a problem that the pattern area and the non-pattern area look different. Therefore, by including the above-mentioned refractive index adjustment layer 140, the refractive index can be compensated to reduce the difference in light transmittance of the optical laminate. Especially when the transparent conductive layer has a pattern, the pattern area and the non-pattern area will not look different.

[0093] In one embodiment, the refractive index of the above-mentioned refractive index adjustment layer 140 can be appropriately selected according to the materials of other adjacent members, preferably it can be 1.4 to 2.6, and more preferably it can be 1.4 to 2.4. In this case, it is possible to prevent light loss caused by a significant refractive index difference between the above-mentioned polarizer 110 and other members and the transparent conductive layer 200.

[0094] The above-mentioned refractive index adjustment layer 140 is not particularly limited as long as it can prevent a significant refractive index difference between other components such as the polarizer 110 and the transparent conductive layer 200, and compounds used for forming the refractive index adjustment layer developed in the past or in the future can be used. For example, it can be formed from a refractive index adjustment layer forming composition containing a polymerizable isocyanurate compound.

[0095] In one embodiment, in addition to the above-mentioned functional layers, the above-mentioned polarizing plate 100 may further include other functional layers to assist or enhance the characteristics of the polarizer. For example, in order to further improve the mechanical durability, an overcoat layer or the like may also be included.

[0096] In one or more embodiments, the above-mentioned 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 this case, an optical laminate with a thin thickness can be manufactured while maintaining the optical characteristics of the above-mentioned polarizing plate 100.

[0097] The above-mentioned transparent conductive layer 200 is provided for driving the liquid crystal layer 300, and can be formed by directly contacting the above-mentioned polarizing plate 100, or can be formed by coating a separate transparent substrate 150.

[0098] For example, as Figure 1 shown in the figure, the first transparent conductive layer 200-1 can be coated on the transparent substrate 150, the first polarizing plate 100-1 can be formed on the above-mentioned transparent substrate 150, and the second transparent conductive layer 200-2 can be formed by directly contacting the second polarizing plate 100-2.

[0099] Conventionally, an optical laminate for manufacturing a smart window or the like is manufactured by forming a conductive layer for liquid crystal driving on one surface of a substrate and laminating a polarizing plate on the other surface of the substrate. However, the transmissivity variable optical laminate of the present invention is characterized in that a conductive layer is directly formed on one surface of the polarizing plate and a separate substrate for forming the conductive layer is intentionally not included, thereby reducing the thickness of the laminate and improving the transmissivity and bending characteristics in the light transmission mode.

[0100] In one embodiment, the above-mentioned transparent conductive layer 200 can be formed by directly evaporating and coating on one side of the above-mentioned transparent substrate 150 or the second polarizing plate 100-2. At this time, for the above-mentioned transparent conductive layer 200, in order to improve the adhesion to the transparent substrate 150 or the second polarizing plate 100-2, after performing pretreatment such as corona treatment or plasma treatment on one side of the transparent substrate 150 or the second polarizing plate 100-2, it can be directly contacted with the pretreated surface of the above-mentioned transparent substrate 150 or the second polarizing plate 100-2 to form. The above-mentioned pretreatment is not limited to corona treatment or plasma treatment, and pretreatment processes developed in the past or in the future can be used within the scope that does not damage the purpose of the present invention.

[0101] In another embodiment, in order to improve the adhesion between the above-mentioned transparent conductive layer 200 and the transparent substrate 150 or the second polarizing plate 100-2, an easy-bonding layer (not shown) provided on one side of the transparent substrate 150 or the second polarizing plate 100-2 can be placed between them and directly contacted with the transparent substrate 150 or the second polarizing plate 100-2 to form. The above-mentioned easy-bonding layer can use the materials described in the adhesion / adhesive layer in other components described later, but is not limited thereto.

[0102] The above-mentioned transparent substrate 150 is the structural basis for forming the above-mentioned first transparent conductive layer 200-1, and there is no particular limitation as long as it is a transparent material that does not reduce the transmittance. Preferably, it may contain one or more selected from the group consisting of 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 polymer (COP), polyimide (PI), polyamideimide (PAI). Preferably, it may contain one or more selected from polyimide (PI) and polyamideimide (PAI).

[0103] As a method of vapor-depositing and coating the above-mentioned transparent conductive layer 200 on one side of the above-mentioned transparent substrate 150 or the second polarizing plate 100-2, it can be formed by a method commonly used in the art. For example, in coating processes such as spin coating, roll coating, bar coating, dip coating, gravure coating, curtain coating, die coating, spray coating, knife coating, kneader coating, etc.; printing (coating) processes such as screen printing, spray printing, inkjet printing, letterpress printing, gravure printing, lithographic printing, etc.; and vapor deposition processes such as chemical vapor deposition (CVD), physical vapor deposition (PVD), plasma enhanced chemical vapor deposition (PECVD), etc., an appropriate process can be selected to form it.

[0104] In the variable transmittance optical laminate of the present invention, the transmittance of the first transparent conductive layer 200-1 with respect to visible light is preferably 50% or more. For example, it may contain 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 materials for transparent conductive layers developed in the past or in the future can be used.

[0105] 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 tin zinc oxide (IZTO), aluminum zinc oxide (AZO), gallium zinc oxide (GZO), fluorine tin oxide (FTO), zinc oxide (ZnO), and the like. Additionally, 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 them. For example, it may include a silver-palladium-copper (APC) alloy or a copper-calcium (CuCa) alloy. The carbon-based material may include one or more selected from the group consisting of carbon nanotubes (CNT) and graphene. The conductive polymer may include one or more selected from the group consisting of polypyrrole, polythiophene, polyacetylene, poly(3,4-ethylenedioxythiophene) (PEDOT), and polyaniline. The conductive polymer may use conductive polymer materials developed in the past or in the future. For example, it may include one or more selected from the group consisting of polythiophene, poly(3,4-ethylenedioxythiophene), polyaniline, polyacetylene, polydiacetylene, polyphenylene, polyphenylene vinylene, polyphenylene sulfide, polythiophene acetylene, polythiophene vinylene, polyfluorene, polypyrrole, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate, poly(3,4-ethylenedioxythiophene):camphorsulfonic acid, poly(3,4-ethylenedioxythiophene):toluenesulfonic acid, poly(3,4-ethylenedioxythiophene):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, and is preferably poly(3,4-ethylenedioxythiophene). The conductive ink may be an ink formed by mixing metal powder and a curable polymer binder. The nanowire may be, for example, a silver nanowire (AgNW). Additionally, the first transparent conductive layer 200-1 may be formed of a structure with two or more layers by combining the above substances. For example, in order to reduce the reflectivity of incident light and increase the transmittance, it may be formed of a two-layer structure including a metal layer and a transparent conductive oxide layer.

[0106] In the variable transmittance optical laminate of the present invention, the second transparent conductive layer 200-2 may contain the conductive polymer, and preferably has a transmittance of 50% or more with respect to visible light. In this case, even if the transparent conductive layer is deformed due to external stress, cracks in the transparent conductive layer can be prevented, and thus an excessive increase in surface resistance can be prevented.

[0107] In one embodiment, the surface of the second transparent conductive layer 200-2 in contact with the liquid crystal layer 300 may be rubbed and oriented. Different from the transparent conductive layer containing a metal component, the conductive polymer contained in the second transparent conductive layer 200-2 of the present invention can form regular grooves on the surface, whereby the liquid crystal compounds in the liquid crystal layer can be arranged at desired positions and in desired directions. 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 no separate alignment film is included, an optical laminate with a thinner thickness can be manufactured, and the manufacturing process can also be simplified.

[0108] The liquid crystal layer 300 included in the variable transmittance optical laminate of the present invention may contain a polymer network 310 as described later, and the polymer network can be formed by a crosslinking reaction of a polymerizable compound. When forming the polymer network 310, an alignment film with a strong surface anchoring ability is required to keep the liquid crystal compounds 320 in the liquid crystal layer uniformly oriented initially. In the present invention, instead of a separate alignment film, a treatment such as a rubbing method and / or a photo-alignment method may be performed on the surface in contact with the liquid crystal layer of the transparent conductive layer, preferably the second transparent conductive layer, in a manner of directly forming an alignment angle. As a method for forming an alignment film, a rubbing method using a rubbing process and a photo-alignment method using ultraviolet rays can be cited. Generally, the photo-alignment method has a weaker surface anchoring ability 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 while the alignment film formed by the photo-alignment method has a surface anchoring energy of about 1×10 -6 J / m 2 Therefore, when forming the polymer network 310 in the liquid crystal layer 300, considering the uniform initial orientation of the liquid crystal compounds 320, it is preferable to rub and orient the surface of the second transparent conductive layer 200-2 of the present invention in contact with the liquid crystal layer 300 by the rubbing method.

[0109] In one embodiment, the above-mentioned transparent conductive layer 200 may have a thickness of less than 1 μm, preferably 10 nm to 500 nm, and more preferably 30 nm to 200 nm. In this case, the above-mentioned transparent conductive layer 200 can ensure a predetermined transmittance and the characteristic change caused by external stress is small, and an optical laminate with a thin thickness can be manufactured.

[0110] The above-mentioned liquid crystal layer 300 can adjust the transmittance of light incident from one or more directions according to the electric field generated by the above-mentioned transparent conductive layer 200, thereby changing the driving mode of the above-mentioned optical laminate to a light-transmitting mode or a light-shielding mode.

[0111] The above-mentioned liquid crystal layer 300 may include a polymer network 310 and a liquid crystal compound 320. For example, it may be disposed between the above-mentioned first transparent conductive layer 200-1 and the second transparent conductive layer 200-2 in the light control region, and may be located within the space provided by the polymer network 310.

[0112] In the past, an optical laminate had to include a sealant and spacers to maintain a certain space required for the liquid crystal compound in the liquid crystal layer, that is, the cell gap. However, in the case of including columnar spacers in the liquid crystal layer to maintain the cell gap, there are problems that the manufacturing process becomes complicated and the manufacturing cost increases, and the alignment film is damaged and the transmittance changes during the process of irradiating ultraviolet rays on the photoresist to form the spacers. In addition, in the case of using spherical spacers to maintain the cell gap of the liquid crystal layer, there are problems that a firm cell gap cannot be maintained and it is difficult to maintain a constant in-plane optical color, and current short circuits of the optical laminate are induced. In addition, in the case of using a sealant to maintain the cell gap of the liquid crystal layer, there are problems that the external light quality may be reduced due to the visibility of the sealant, and the sealant may break during the handling of the optical laminate or there may be defects due to the thickness difference from the spacers included at the same time.

[0113] The liquid crystal layer 300 included in the variable transmittance optical laminate of the present invention includes both a liquid crystal compound 320 and a polymer network 310 at the same time, so that the cell gap of the liquid crystal layer can be appropriately maintained even without including a separate sealant and / or spacers. In addition, since the cell gap is maintained by a single polymer network structure instead of a combination of a sealant and spacers, it has the advantage of being able to fundamentally block defects caused by the thickness difference between the sealant and the spacers.

[0114] The above-mentioned liquid crystal compound is not particularly limited as long as it can be driven by an electric field to control the transmittance of light. Liquid crystal compounds developed in the past or in the future can be used. For example, the content of the reactive liquid crystal compound regarding the above-mentioned coating type polarizer can be similarly applied.

[0115] The above liquid crystal compound may include a chiral nematic (cholesteric) liquid crystal compound, and the above chiral nematic liquid crystal compound may include a nematic liquid crystal compound and a chiral compound.

[0116] In the above nematic liquid crystal compound, the rod-shaped molecules are arranged parallel to each other. Although the central positions of the molecules are irregular, the directions of the molecular axes are ordered. Each molecule of the nematic liquid crystal compound can move freely in the long axis direction, so it has low viscosity and good fluidity. And because the up-down directions of each molecule are almost the same, the polarizations cancel each other out, and generally it does not exhibit strong dielectric properties. There is no particular limitation on the type of the above nematic liquid crystal compound, as long as it contains a mesogenic group, there is no restriction.

[0117] The steric structures of the above chiral compounds have structures that are symmetric to each other like the relationship between the right hand and the left hand. Although their chemical structures and physical properties are the same, due to their mirror image relationship, they are compounds with different steric structures. If a certain content of chiral compound is included in the above nematic liquid crystal compound, a helical cycle will be induced. Regarding the type of the above chiral compound, as long as it can induce the target helical cycle without damaging the liquid crystallinity of the above liquid crystal compound, such as nematic regularity, it can be used without particular limitation.

[0118] The chiral compound used to induce a helical cycle in the liquid crystal compound needs to contain at least chirality in its molecular structure. As the above chiral compound, for example, compounds having one or more asymmetric carbons, compounds having an asymmetric point on a heteroatom such as chiral amines or chiral sulfoxides, or compounds having an axially asymmetric and optically active site such as cumulene or binaphthol can be exemplified.

[0119] The above chiral compound can be, for example, a low molecular weight compound with a molecular weight of 1,500 or less. For example, as the chiral compound, commercially available chiral nematic liquid crystals can be used. For example, chiral doped liquid crystal S-811 or Paliocolor LC 756 (manufactured by BASF) sold by Merck & Co., Inc. etc., but not limited thereto.

[0120] In the above chiral nematic liquid crystal compound, based on the total weight of the chiral nematic liquid crystal compound, the nematic liquid crystal compound may be contained in an amount of 75 to 99% by weight and the chiral compound may be contained in an amount of 1 to 25% by weight, but it is not limited thereto. By appropriately adjusting the contents of the nematic liquid crystal compound and the chiral compound within the above ranges, the helical cycle of the chiral nematic liquid crystal compound, that is, the pitch, can be adjusted. The pitch of the above chiral nematic liquid crystal compound is not particularly limited and may be 5 to 20 μm.

[0121] There is no particular limitation on the liquid crystal behavior mode of the above liquid crystal layer 300. For example, a twisted nematic (TN) mode, a super twisted nematic (STN) mode, an in-plane switching (IPS) mode, a fringe-field switching (FFS) mode, a vertical alignment (VA) mode, etc. can be used. From the aspect of controlling the light transmittance, the twisted nematic (TN) mode is preferably used.

[0122] As an example of a polymer contained in a liquid crystal layer in the past, polymer dispersed liquid crystal (PDLC) is known. In the above polymer dispersed liquid crystal, the liquid crystal compound phase-separates and exists in the polymer in the form of droplets or capsules. The liquid crystal compound in the form of the phase-separated droplets or capsules is arranged in irregular directions, and thus cannot have a constant initial orientation. That is, in the state where no voltage is applied, the liquid crystal compound in the polymer dispersed liquid crystal (PDLC) is irregularly arranged to scatter the incident light, thereby maintaining an opaque state (light-shielding mode). In the state where a voltage is applied, the liquid crystal compound is arranged in one direction to allow the incident light to pass through, thereby forming a transparent state (light-transmitting mode). However, in the light-shielding mode of the polymer dispersed liquid crystal (PDLC), the property that the incident light is scattered due to the irregular arrangement of the liquid crystal compound is utilized. Therefore, there is a technical limitation that the light scattered in an arbitrary direction cannot be controlled and the light-shielding rate is somewhat unsatisfactory. In addition, in order to achieve the light-transmitting mode, it is necessary to maintain the state where a voltage is applied. Therefore, it is pointed out that there is a disadvantage of high power consumption.

[0123] The liquid crystal layer 300 of the present invention includes a polymer network 310 and a liquid crystal compound 320, and the above liquid crystal compound 320 is arranged in a uniform initial orientation. The liquid crystal layer 300 of the present invention not only includes a polymer network 310, but also the included liquid crystal compound 320 does not phase-separate in the form of droplets or capsules, but exists in a form mixed with the polymer network 310 and is arranged in a uniform initial orientation within the liquid crystal layer, which is different from the conventional polymer dispersed liquid crystal (PDLC). Thus, the liquid crystal layer 300 of the present invention including a polymer network 310 and a liquid crystal compound 320 arranged in a uniform initial orientation can adjust the transmittance of light incident from one or more directions according to the electric field generated by the transparent conductive layer 200, thereby realizing a light-transmitting mode and a light-shielding mode. Therefore, compared with the conventional polymer dispersed liquid crystal that scatters incident light to realize the light-shielding mode, a more excellent light-shielding rate can be shown. In addition, the variable transmittance optical laminate of the present invention can realize the light-transmitting mode in a state where no voltage is applied by appropriately adjusting the transmission axis of the polarizing plate 100 and the optical axis of the liquid crystal layer 300, and compared with the conventional polymer dispersed liquid crystal in which the liquid crystal is disorderly arranged, the applied voltage required during driving is low, which has the advantage of being able to reduce power consumption compared with the conventional polymer dispersed liquid crystal.

[0124] The above liquid crystal layer 300 may include a cured product of a liquid crystal layer-forming composition containing a polymerizable monomer and a liquid crystal compound.

[0125] The above polymerizable monomer refers to a compound that forms a polymer network through a photopolymerization reaction or a thermal polymerization reaction, and there is no particular limitation. For example, it may include acrylate monomers, and may include one or more selected from the group consisting of isobornyl acrylate, caprolactone acrylate, triethylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, and dipentaerythritol pentaacrylate.

[0126] The above polymerizable monomer may include one or more monomers selected from monofunctional monomers to tetrafunctional monomers, and preferably may include trifunctional monomers. Multifunctional monomers have the advantages of not causing an impact on the liquid crystal, having excellent compatibility with the liquid crystal, and being able to exhibit appropriate phase separation from the liquid crystal.

[0127] The above liquid crystal layer-forming composition may include 10 to 30% by weight of the polymerizable monomer based on the total weight of the composition, and preferably may include 10 to 20% by weight. When the liquid crystal layer-forming composition includes the above polymerizable monomer in the above content range, it has the advantages that the curing degree of the polymer network formed thereby is sufficient to stably maintain the cell gap of the liquid crystal layer, and excellent light transmittance and adhesion can be obtained, and thus it is preferred.

[0128] The method for forming the liquid crystal layer 300 using the above-described liquid crystal layer-forming composition is not particularly limited. For example, it can be formed by coating the above-described liquid crystal layer-forming composition on the second transparent conductive layer 200-2 whose surface has been rubbed and aligned and then photocuring or thermocuring it.

[0129] The variable transmittance optical laminate of the present invention includes a polymer network 310 in the liquid crystal layer 300. Therefore, a stable cell gap can be maintained even without including a sealant and spacers. However, one or more of a sealant and spacers can be further added as needed within the scope that does not impair the object of the present invention.

[0130] The above sealant can contain a curable resin as a base resin. As the above base resin, an ultraviolet curable resin or a thermosetting resin known in the art and usable for a sealant can be used. The above ultraviolet curable resin can be a polymer of an ultraviolet curable monomer. The above thermosetting resin can be a polymer of a thermosetting monomer.

[0131] As the base resin of the above sealant, for example, an acrylate resin, an epoxy resin, a urethane resin, a phenol resin, or a mixture of the above resins can be used. In one embodiment, the above base resin can be an acrylate resin, and the above acrylate resin can be a polymer of an acrylic monomer. The above acrylic monomer can be, for example, a polyfunctional acrylate. In another embodiment, the above sealant can further contain a monomer component in the base resin. The above monomer component can be, for example, a monofunctional acrylate. In the present specification, a monofunctional acrylate can refer to a compound having 1 acryloyl group, and a polyfunctional acrylate can refer to a compound having 2 or more acryloyl groups. The above curable resin can be cured by irradiating ultraviolet rays and / or heating. Regarding the above ultraviolet irradiation conditions or heating conditions, they can be appropriately implemented within the scope that does not impair the object of the present application. The above sealant can also contain an initiator as needed, such as a photoinitiator or a thermal initiator.

[0132] The above sealant can be formed by a method commonly used in the art. For example, it can be formed by applying the sealant to the periphery (i.e., the non-active region) of the above liquid crystal layer using a dispenser equipped with a nozzle.

[0133] The above-mentioned spacer may include at least one of a ball spacer and a column spacer, and particularly preferably a ball spacer. The above-mentioned ball spacer may be one or more, preferably having a diameter of 1 to 10 μm. In addition, when viewed from the top-down direction, considering the visibility of the user and the transmittance in the enhanced light transmission mode, the area occupied by the above-mentioned ball spacer in the liquid crystal layer 300 is preferably 0.01 to 10% of the area of the liquid crystal layer 300.

[0134] The variable transmittance optical laminate of the present invention may further include other components within the scope that does not damage the object of the present invention. For example, it may further include an adhesive / bonding layer 400 (refer to Figure 3 ), and may also further include an ultraviolet absorption layer, a hard coat layer, etc.

[0135] The above-mentioned adhesive / bonding layer 400 may be formed using an adhesive or an adhesive agent, and preferably has appropriate adhesive / adhesive force to prevent peeling, bubbles, etc. from occurring during the handling of the optical laminate, and also has transparency and thermal stability.

[0136] The above-mentioned adhesive may use adhesives developed in the past or in the future. For example, a photocurable adhesive may be used.

[0137] The above-mentioned photocurable adhesive exhibits strong adhesive force by undergoing crosslinking and curing upon receiving active energy rays such as ultraviolet rays (UV) and electron beams (EB), and may be composed of a reactive oligomer, a reactive monomer, a photoinitiator, etc.

[0138] The above-mentioned reactive oligomer is an important component that determines the characteristics of the adhesive, and forms a cured film by forming a polymer bond through a photopolymerization reaction. Examples of the reactive oligomer that can be used include polyester-based resins, polyether-based resins, polyurethane-based resins, epoxy-based resins, polyacrylic-based resins, silicone-based resins, etc.

[0139] The above-mentioned reactive monomer functions as a crosslinking agent and a diluent for the above-mentioned reactive oligomer, and also affects the adhesive characteristics. Examples of the reactive monomer that can be used include monofunctional monomers, polyfunctional monomers, epoxy-based monomers, vinyl ethers, cyclic ethers, etc.

[0140] The above-mentioned photoinitiator functions to absorb light energy to generate free radicals or cations to initiate photopolymerization, and a suitable photoinitiator can be selected according to the photopolymerization resin.

[0141] The above-mentioned adhesive can be an adhesive developed in the past or in the future. In one or more embodiments, 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. can be used. The above-mentioned adhesive is not particularly limited as long as it has adhesiveness and viscoelasticity, but considering aspects such as ease of acquisition, an acrylic adhesive is preferably used. For example, it can contain a (meth)acrylate copolymer, a crosslinking agent, a solvent, etc.

[0142] The above-mentioned crosslinking agent can be a crosslinking agent developed in the past or in the future. For example, it can contain a polyisocyanate compound, an epoxy resin, a melamine resin, a urea resin, a dialdehyde, a hydroxymethyl polymer, etc., and preferably contains a polyisocyanate compound.

[0143] The above-mentioned solvent can contain common solvents used in the field of resin compositions. For example, alcohol-based compounds such as methanol, ethanol, isopropanol, butanol, and propylene glycol monomethyl ether; ketone-based compounds such as methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, and dipropyl ketone; acetate-based compounds such as methyl acetate, ethyl acetate, butyl acetate, and propylene glycol monomethyl acetate; cellosolve-based compounds such as methyl cellosolve, ethyl cellosolve, and propyl cellosolve; hydrocarbon-based compounds such as hexane, heptane, benzene, toluene, and xylene can be used as solvents. They can be used alone or in combination of two or more.

[0144] The thickness of the above-mentioned adhesion / bonding layer 400 can be appropriately determined according to the type of resin that functions as the adhesion / bonding body, the adhesion / bonding strength, the environment in which the adhesive is used, etc. In one embodiment, in order to ensure sufficient adhesion / cohesive force and minimize the thickness of the optical laminate, the thickness of the above-mentioned adhesion / bonding layer can be 0.01 to 50 μm, preferably can have a thickness of 0.05 to 20 μm, and more preferably can have a thickness of 0.1 to 10 μm.

[0145] The above-mentioned ultraviolet absorption layer is not particularly limited as long as it is used to prevent the deterioration of the optical laminate caused by ultraviolet rays. For example, salicylic acid-based ultraviolet absorbers (such as phenyl salicylate, p-tert-butyl salicylate, etc.), benzophenone-based ultraviolet absorbers (such as 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, etc.), benzotriazole-based ultraviolet absorbers (such as 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)benzotriazole, 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-benzotriazol-2-yl)phenol), 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 branched dodecyl)-4-methylphenol, octyl 3-[3-tert-butyl-4-hydroxy-5-(chloro-2H-benzotriazol-2-yl)phenyl]propionate, and a mixture of 2-ethylhexyl 3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazol-2-yl)phenyl]propionate, etc.), cyanoacrylate-based ultraviolet absorbers (such as 2'-ethylhexyl 2-cyano-3,3-diphenylacrylate, ethyl 2-cyano-3-(3',4'-methylenedioxyphenyl)acrylate, etc.), triazine-based ultraviolet absorbers, etc. Benzotriazole-based ultraviolet absorbers or triazine-based ultraviolet absorbers with high transparency and excellent effects in preventing the deterioration of polarizing plates or transmittance variable layers are preferred, and benzotriazole-based ultraviolet absorbers with more suitable spectral absorption spectra are particularly preferred. The above-mentioned benzotriazole-based ultraviolet absorbers can also be bis-ified substances. For example, they can be 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.

[0146] The above-mentioned hard coat is not particularly limited as long as it is used to protect components such as polarizing plates and transmittance variable layers from external physical and chemical impacts, and hard coats developed in the past or in the future can be used.

[0147] In one embodiment, the above hard coat can be formed by applying a composition for forming a hard coat on other members and then curing it using light or heat. The composition for forming the hard coat is not particularly limited. For example, it may contain a photocurable compound and a photoinitiator.

[0148] The above photocurable compound and photoinitiator can be substances generally used in the art without limitation. For example, the above photocurable compound can be a photopolymerizable monomer, a photopolymerizable oligomer, etc. For example, monofunctional and / or polyfunctional (meth)acrylates can be cited. As for the photoinitiator, hydroxycyclohexyl phenyl ketone, trimethylbenzoyl diphenyl phosphine oxide, acetophenone-based, oxime ester-based, etc. can be cited. As commercially available products, Irgacure-184, TPO, Irgacure-907, etc. can be cited.

[0149] <Method for manufacturing a variable transmittance optical laminate>

[0150] The variable transmittance optical laminate of the present invention described above can be formed by a roll-to-roll process, including the steps of forming a first transparent conductive layer 200-1 on a transparent substrate 150, forming a second transparent conductive layer 200-2 and a liquid crystal layer 300 on a second polarizing plate, and laminating the liquid crystal layer 300 and the first transparent conductive layer 200-1.

[0151] That is, the method for manufacturing a variable transmittance optical laminate of the present invention may include: (a) a step of preparing a first polarizing plate; (b) a step of forming a first transparent conductive layer on a transparent substrate; (c) a step of forming a second transparent conductive layer on a second polarizing plate; (d) a step of forming a liquid crystal layer by applying a composition for forming a liquid crystal layer on the second transparent conductive layer; (e) a step of laminating the first transparent conductive layer of the laminate formed in step (b) and the liquid crystal layer of the laminate formed in step (d) in such a way that they are in contact; and (f) a step of laminating the first polarizing plate prepared in step (a) on the transparent substrate of the laminate formed in step (e), wherein in step (f), the first polarizing plate and the second polarizing plate are laminated in such a way that their absorption axes are orthogonal to each other in a plan view, and steps (b) to (e) are carried out by a roll-to-roll process.

[0152] The method for manufacturing a variable transmittance optical laminate of the present invention is a method for manufacturing the above variable transmittance optical laminate, and the content of the above <variable transmittance optical laminate> can be applied without limitation.

[0153] Figure 4 It is a diagram schematically showing a method for manufacturing a variable transmittance optical laminate according to an embodiment of the present invention.

[0154] Refer to Figure 4, the second polarizing plate 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 can each continuously advance through a roll-to-roll process in different production lines, and can continuously advance in a direction in which the two production lines are laminated while meeting each other.

[0155] Hereinafter, the manufacturing method of the variable transmittance optical laminate of the present invention will be described according to steps.

[0156] (a) Step of preparing the first polarizing plate

[0157] First, prepare the first polarizing plate 100-1 in a manner that can be used for step (f).

[0158] It can be attached to the transparent substrate 150 by forming an adhesive / bonding layer on the first polarizing plate 100-1. In this case, the process of forming the adhesive / bonding layer on the first polarizing plate 100-1 can utilize a roll-to-roll process.

[0159] The above-mentioned first polarizing plate 100-1 and the adhesive / bonding layer can equally apply the contents of the polarizing plate 100 and the adhesive / bonding layer 400 described in the above <variable transmittance optical laminate>.

[0160] After that, it is prepared by cutting in a manner that can be laminated orthogonally to the absorption axis of the second polarizing plate 100-2 in a plan view.

[0161] (b) Step of forming the first transparent conductive layer on the transparent substrate

[0162] The first transparent conductive layer 200-1 is formed on the transparent substrate 150, and this can be manufactured by a roll-to-roll process.

[0163] The above-mentioned first transparent conductive layer 200-1 can be formed by evaporation or coating on one surface of the transparent substrate 150. At this time, in order to improve the adhesion, a pretreatment such as corona treatment or plasma treatment can be performed on one surface of the transparent substrate 150 before forming the first transparent conductive layer 200-1.

[0164] Alternatively, an easy-bonding layer (not shown) can be provided on one surface of the transparent substrate 150 to attach and form the first transparent conductive layer 200-1.

[0165] The above-mentioned first transparent conductive layer 200-1, the transparent substrate 150, and the easy-bonding layer can equally apply the contents of the transparent conductive layer 200, the transparent substrate 150, and the adhesive / bonding layer 400 described in the above <variable transmittance optical laminate>.

[0166] (c) Step of forming the second transparent conductive layer on the second polarizing plate

[0167] Prepare the second polarizing plate 100-2, and form the second transparent conductive layer 200-2 through a roll-to-roll process.

[0168] The above-mentioned second transparent conductive layer 200-2 can be formed by directly coating one side of the above-mentioned second polarizing plate 100-2. At this time, in order to improve the adhesion, pre-treatments such as corona treatment or plasma treatment can be performed on one side of the above-mentioned second polarizing plate 100-2 and then directly contacted with the second transparent conductive layer 200-2 to form it.

[0169] In addition, an easy-bonding layer (not shown) can also be provided on one side of the above-mentioned second polarizing plate 100-2 to adhere and form the second transparent conductive layer 200-2.

[0170] The above-mentioned second polarizing plate 100-2, second transparent conductive layer 200-2, and easy-bonding layer can equally apply the content of the polarizing plate 100, transparent conductive layer 200, and adhesive / bonding layer 400 described in the above <transmittance-variable optical laminate>.

[0171] After the above step (c), through a roll-to-roll process, while passing through the alignment forming section 250, regular grooves are formed on the surface of the second transparent conductive layer 200-2, thereby enabling rubbing alignment.

[0172] The above-mentioned second transparent conductive layer 200-2 contains a conductive polymer. Different from the transparent conductive layer containing a metal component, the above-mentioned conductive polymer can form regular grooves on the surface, so that the liquid crystal compounds in the liquid crystal layer can be arranged at desired positions and directions.

[0173] Since rubbing is obtained in the forward direction (MD direction) through the above roll-to-roll continuous process, it will be aligned at a certain angle, and the alignment angle of the second transparent conductive layer 200-2 can be formed in a manner consistent with the absorption axis of the above-mentioned second polarizing plate 100-2. For example, the absorption axis of the above-mentioned second polarizing plate 100-2 can be 0°, and the alignment angle formed in the second transparent conductive layer 200-2 can be 0°.

[0174] (d) Step of forming the liquid crystal layer by coating the liquid crystal layer-forming composition on the second transparent conductive layer

[0175] As described above, the liquid crystal layer 300 included in the transmittance-variable optical laminate of the present invention simultaneously includes liquid crystal compounds 320 and a polymer network 310. Therefore, even without a separate sealant and / or spacer, the cell gap of the liquid crystal layer can be appropriately maintained, and the content regarding the liquid crystal layer 300 described in the above <transmittance-variable optical laminate> can be applied without limitation.

[0176] The above liquid crystal layer 300 can be formed by using a liquid crystal layer-forming composition containing a polymerizable monomer and a liquid crystal compound. After the above step (c), while continuously passing through the liquid crystal layer-forming section 350 by a roll-to-roll process, the liquid crystal layer-forming composition is coated on the second transparent conductive layer 200-2 after rubbing alignment and cured (not shown), thereby forming the liquid crystal layer 300.

[0177] (e) Step of laminating in such a manner that the first transparent conductive layer of the laminate formed in the above step (b) is in contact with the liquid crystal layer of the laminate formed in the above step (d) (f) Step of laminating the first polarizing plate prepared in the above step (a) on the transparent substrate of the laminate formed in the above step (e)

[0178] Laminating is performed in such a manner that the first transparent conductive layer 200-1 in the laminate formed in the above step (b) is in contact with the liquid crystal layer 300 formed in the above step (d).

[0179] At this time, the laminate formed in the above step (b) and the laminate having the liquid crystal layer 300 formed in the above step (d) can be conveyed along different tracks, and the first transparent conductive layer 200-1 and the liquid crystal layer 300 can be laminated with each other by a roll-to-roll process.

[0180] ​ ​

[0181] After the above step (e), the first polarizing plate 100-1 prepared in the above step (a) and the second polarizing plate 100-2 are laminated in such a manner that their absorption axes are orthogonal to each other.

[0182] That is, after sequentially laminating the second polarizing plate 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 by a roll-to-roll process, the first polarizing plate 100-1 is laminated so that its absorption axis is perpendicular to the absorption axis of the second polarizing plate 100-2 in the plan view, thereby manufacturing the variable transmittance optical laminate of the present invention.

[0183] For example, the absorption axis of the second polarizing plate 100-2 can be 0°, and the absorption axis of the first polarizing plate 100-1 can be 90°.

[0184] At this time, by arranging the absorption axes of the first polarizing plate 100-1 and the second polarizing plate 100-2 perpendicular to each other in the plan view, it is possible to improve the variable transmittance range between the light-transmitting mode (ON) and the light-blocking mode (OFF) of the optical laminate based on liquid crystal driving.

[0185] In this way, since the variable transmittance optical laminate is manufactured by forming the liquid crystal layer through a continuous roll-to-roll process, the process is continuous and can be manufactured economically.

[0186] <Smart windows, automotive and building windows>

[0187] In addition to the above-described transmittance variable optical laminate, the present invention further includes a smart window including the above-described transmittance variable optical laminate. Further, the present invention includes an automobile in which the above-described smart window is applied to at least one of a front window, a rear window, a side window, a sunroof, and an interior partition, and a building window including the above-described smart window.

Claims

1. A variable transmittance optical stack, comprising: a first polarizing plate; a transparent substrate laminated on one side of the first polarizing plate; A first transparent conductive layer formed on the transparent substrate; a second polarizing plate, which is opposite to the first polarizing plate; A second transparent conductive layer formed on one side of the second polarizing plate and opposite to the first transparent conductive layer; as well as a liquid crystal layer disposed between the first transparent conductive layer and the second transparent conductive layer, The second transparent conductive layer comprises a conductive polymer. The liquid crystal layer comprises a polymer network and a liquid crystal compound, The liquid crystal compound is arranged in a uniform initial orientation.

2. The variable transmittance optical stack 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 stack 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 stack according to claim 1, wherein: The liquid crystal layer includes a cured product of a liquid crystal layer-forming composition containing a polymerizable monomer and a liquid crystal compound.

5. The variable transmittance optical stack according to claim 4, wherein: The composition for forming a liquid crystal layer includes 10 to 30 wt % of a polymerizable monomer based on the total weight of the composition.

6. The variable transmittance optical stack according to claim 1, wherein: The surface of the second transparent conductive layer in contact with the liquid crystal layer is rubbed and aligned.

7. The variable transmittance optical stack according to claim 1, wherein: The conductive polymer comprises one or more selected from the group consisting of polythiophene, poly(3,4-ethylenedioxythiophene), polyaniline, polyacetylene, polydiacetylene, polyphenylene, polyphenylene vinylene, polyphenylene sulfide, polythiophene acetylene, polythiophene vinylene, polyfluorene, polypyrrole, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate, poly(3,4-ethylenedioxythiophene):camphorsulfonic acid, poly(3,4-ethylenedioxythiophene):toluenesulfonic acid, poly(3,4-ethylenedioxythiophene):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 stack according to claim 1, wherein: The second transparent conductive layer is formed to be in direct contact with the second polarizing plate without including a separate substrate.

9. The variable transmittance optical stack according to claim 1, wherein: The second transparent conductive layer is formed so as to be in direct contact with the second polarizing plate by including an easy-adhesion layer therebetween.

10. The variable transmittance optical stack 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 stack 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 stack according to claim 1, wherein: The variable transmittance optical layered body further includes at least one selected from the group consisting of an adhesive / bonding layer, an ultraviolet absorbing layer, and a hard coating layer.

13. A method for manufacturing a variable transmittance optical stack, comprising: (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 the second polarizing plate; (d) a step of coating a liquid crystal layer-forming composition on the second transparent conductive layer to form a liquid crystal layer; (e) laminating the stacked body formed in the step (b) so that the first transparent conductive layer is in contact with the liquid crystal layer of the stacked body formed in the step (d); and (f) laminating the first polarizing plate prepared in step (a) on the transparent substrate of the laminate formed in step (e), In the step (f), the first polarizing plate and the second polarizing plate are laminated in such a manner that the absorption axis of the first polarizing plate and the absorption axis of the second polarizing plate are orthogonal to each other in the plan view direction. The steps (b) to (e) are performed by a roll-to-roll process.

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

15. The method for producing a variable transmittance optical layered body according to claim 13, wherein: Between the steps (c) and (d), the method further includes a step of causing the surface of the second transparent conductive layer in contact with the liquid crystal layer to form a rubbing alignment.

16. The method for producing a variable transmittance optical layered body according to claim 13, wherein: In the step (c), the second transparent conductive layer is formed to be in direct contact with the second polarizing plate without including a separate substrate.

17. The method for producing a variable transmittance optical layered body according to claim 13, wherein: In the step (c), the second transparent conductive layer is formed so as to be in direct contact with the second polarizing plate by including an easy-adhesion layer therebetween.

18. The method for producing a variable transmittance optical layered body 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 producing a variable transmittance optical layered body 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 layered body according to claim 13, wherein: The liquid crystal layer includes a cured product of a liquid crystal layer-forming composition containing a polymerizable monomer and a liquid crystal compound.

21. The method for producing a variable transmittance optical layered body according to claim 13, wherein: The liquid crystal layer includes a polymer network and a liquid crystal compound.

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

23. An automobile, wherein the smart window according to claim 22 is applied to at least one of a front window, a rear window, a side window, a skylight, and an interior partition.

24. A window for a building, comprising the smart window according to claim 22.

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