Optical laminate and smart window including the same

Abstract

The present invention includes a dimming laminate including a first polarizing plate, a first transparent conductive layer formed on one surface of the first polarizing plate, 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, at least one of a surface protection film and a hard coating layer being provided on one surface or both surfaces of the dimming laminate. At least one of the first transparent conductive layer and the second transparent conductive layer is formed in direct contact with one of the first polarizing plate and the second polarizing plate. The surface protection film has a peel strength of 1.0 N / 25 mm to 2.4 N / 25 mm, and the hard coating layer has a surface pencil hardness of HB to 6H. The present invention relates to a variable transmittance optical laminate and a smart window including the same.

Description

[Technical Field]

[0001] The present invention relates to optical stacks and smart windows including the same. [Background technology]

[0002] Generally, glass windows of vehicles and other transportation means are often coated with an external light blocking coating. However, conventional glass windows of transportation means have a fixed transmittance, and the external light blocking coating also has a fixed transmittance. Therefore, such conventional transportation windows have a fixed overall transmittance, which can lead to accidents. For example, if the overall transmittance is set low, there is no problem during the day when there is sufficient ambient light, but there is a problem that drivers have difficulty properly checking the surroundings of the vehicle at night when there is insufficient ambient light. Alternatively, if the overall transmittance is set high, there is a problem that drivers may experience glare during the day when there is sufficient ambient light. For this reason, a variable transmittance optical laminate has been developed that can change light transmittance when a voltage is applied.

[0003] Meanwhile, when manufacturing a smart window using such a variable transmittance optical laminate, the optical laminate is generally manufactured, and then glass is bonded to one or both sides of the optical laminate.

[0004] However, if the optical laminate is damaged or scratched on its surface before being bonded to glass, i.e., during handling such as manufacturing or transporting the optical laminate, there is a problem that the optical properties of the optical laminate may be deteriorated.

[0005] Therefore, there is a need to protect the optical laminate used in manufacturing smart windows from surface damage or scratches that may occur during handling of the optical laminate itself.

[0006] Therefore, a surface protective film is used that can be attached to one or both sides of the optical laminate to protect the optical laminate from surface damage or scratches, and for example, Korean Patent Publication No. 10-2001-0101097 also discloses a surface protective film.

[0007] However, in the case of such surface protection films, if the peel strength from the adhesive surface is insufficient, there is a problem of air bubbles forming at the interface between the surface protection film and the adhesive surface during the deposition process of ITO, etc., and if the peel strength from the adhesive surface is too strong, there are problems such as the film inside the laminate peeling off during the peeling process or air bubbles entering inside the liquid crystal.

[0008] The Korean Patent Publication No. 10-2001-0101097 also has a problem that the peel strength is insufficient for use in the manufacturing process of an optical laminate for smart windows, and bubbles are generated at the interface between the surface protection film and the adhesive surface during the ITO deposition process.

[0009] Therefore, there is an increasing need for an optical laminate provided with a surface protection film or the like that can protect the optical laminate without causing such problems. Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide a variable transmittance optical stack that can protect a light-controlling stack from external impacts or scratches and prevent damage to the light-controlling stack that may occur during processing. [Means for solving the problem]

[0011] To achieve the above object, the present invention provides a variable transmittance optical laminate including a first polarizer, a first transparent conductive layer formed on one side of the first polarizer, a second polarizer facing the first polarizer, a second transparent conductive layer formed on one side of the second polarizer 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, and at least one of a surface protection film and a hard coating layer is provided on one or both sides of the light control laminate, at least one of the first transparent conductive layer and the second transparent conductive layer is formed in direct contact with one of the first polarizer and the second polarizer, the surface protection film has a peel strength of 1.0 N / 25 mm to 2.4 N / 25 mm, and the hard coating layer has a surface pencil hardness of HB to 6H. [Effects of the Invention]

[0012] According to an optical laminate according to one embodiment of the present invention, the peeling force of the surface protection film is optimized, and damage to the sealant and the intrusion of air bubbles into the liquid crystal can be prevented when the surface protection film is peeled off.

[0013] In addition, according to an optical laminate according to one embodiment of the present invention, the peel strength of the surface protection film is optimized, and it is possible to prevent air bubbles from entering between the light control laminate and the surface protection film during vacuum deposition of the transparent conductive layer.

[0014] In addition, according to another embodiment of the optical laminate of the present invention, the surface pencil hardness of the hard coating layer is optimized, and one or both surfaces of the light-controlling laminate can be protected from post-processing and the external environment without providing a surface protective film on the optical laminate. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a diagram showing the layer structure of a light-control laminate according to one embodiment of the present invention. [Figure 2a] FIG. 2a is a diagram showing a stack structure of a polarizer according to one or more embodiments of the present invention. [Figure 2b] FIG. 2b is a diagram showing a stack structure of a polarizer according to one or more embodiments of the present invention. [Figure 2c] FIG. 2c shows a stack structure of a polarizer according to one or more embodiments of the present invention. [Figure 2d] FIG. 2d shows a stack structure of a polarizer according to one or more embodiments of the present invention. [Figure 2e] 2e is a diagram showing a stack structure of a polarizing plate according to one or more embodiments of the present invention. [Figure 3] FIG. 3 is a diagram showing a layer structure of a variable transmittance optical laminate according to one or more embodiments of the present invention. [Figure 4] FIG. 4 is a diagram showing a layer structure of a variable transmittance optical laminate according to one or more embodiments of the present invention. [Figure 5a] FIG. 5a is a diagram illustrating a stacked structure of a smart window in accordance with one or more embodiments of the present invention. [Figure 5b] FIG. 5b is a diagram illustrating a stacked structure of a smart window in accordance with one or more embodiments of the present invention. [Figure 5c] FIG. 5c illustrates a stacked structure of a smart window in accordance with one or more embodiments of the present invention. [Figure 6a] FIG. 6a is a diagram illustrating a stacked structure of a smart window in accordance with one or more embodiments of the present invention. [Figure 6b] FIG. 6b is a diagram illustrating a stacked structure of a smart window in accordance with one or more embodiments of the present invention. [Figure 6c] FIG. 6c illustrates a stacked structure of a smart window in accordance with one or more embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention relates to a variable transmittance optical laminate that can prevent damage to the sealant and the intrusion of air bubbles into the liquid crystal when the surface protective film is peeled off by optimizing the peel force of the surface protective film, and can prevent the intrusion of air bubbles between the light control laminate and the surface protective film when a transparent conductive layer is vacuum-deposited.

[0017] The present invention also relates to a variable transmittance optical laminate that can protect one or both surfaces of the light-controlling laminate from post-processing and the external environment by optimizing the surface pencil hardness of the hard coating layer, even without providing the optical laminate with a surface protective film.

[0018] More specifically, the present invention relates to a variable transmittance optical laminate including a first polarizer, a first transparent conductive layer formed on one side of the first polarizer, a second polarizer facing the first polarizer, a second transparent conductive layer formed on one side of the second polarizer 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, and at least one of a surface protection film and a hard coating layer is provided on one or both sides of the light control laminate, at least one of the first transparent conductive layer and the second transparent conductive layer is formed in direct contact with one of the first polarizer and the second polarizer, the surface protection film has a peel strength of 1.0 N / 25 mm to 2.4 N / 25 mm, and the hard coating layer has a surface pencil hardness of HB to 6H.

[0019] The variable transmittance optical laminate of the present invention is particularly suitable for technical fields in which light transmittance can be changed by applying a voltage, and may be used, for example, in smart windows.

[0020] A smart window is an optical structure that controls the amount of light or heat passing through by changing its light transmittance in response to the application of an electrical signal. That is, a smart window can be changed between transparent, opaque, or translucent depending on the voltage applied, and is also called variable transmittance glass, light-control glass, or smart glass.

[0021] Smart windows can be used as partitions for dividing or protecting privacy within the interior spaces of vehicles and buildings, or as light windows placed in openings in buildings. They can also be used for highway signs, bulletin boards, odometers, clocks, or advertising screens, and can replace glass in the windows or sunroofs of automobiles, buses, airplanes, ships, or trains.

[0022] The variable transmittance optical laminate of the present invention can also be used in smart windows in the various technical fields mentioned above. However, since the conductive layer is formed directly on the polarizer, no separate substrate is required for forming the conductive layer, resulting in a thin thickness and advantageous flexibility, making it particularly suitable for use in smart windows for vehicles or buildings. In one or more embodiments, smart windows using the variable transmittance optical laminate of the present invention can be used in transportation, such as front windows, rear windows, side windows, and sunroof windows of automobiles, or building fixtures. In addition to applications for blocking external light, they can also be used to divide interior spaces such as automobiles or buildings, such as interior partitions, or for privacy protection. They can also be used in wearable devices such as helmets, glasses, and watches.

[0023] Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings. However, the following drawings attached to this specification are intended to illustrate preferred embodiments of the present invention and to facilitate a better understanding of the technical concept of the present invention together with the above-described content of the invention, and therefore the present invention should not be interpreted as being limited only to the details shown in these drawings.

[0024] The terms used herein are for the purpose of describing the embodiments and are not intended to limit the present invention. In this specification, the singular form includes the plural form unless otherwise specified. For example, the term "polarizer" used herein may refer to at least one polarizer of the first polarizer and the second polarizer, and the term "transparent conductive layer" may refer to at least one transparent conductive layer of the first transparent conductive layer and the second transparent conductive layer.

[0025] As used herein, the terms "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components, steps, operations and / or elements other than the stated components, steps, operations and / or elements. Like reference numerals refer to like elements throughout the specification.

[0026] Spatially relative terms such as "below," "bottom," "lower," "upper," "top," "top," and the like may be used to easily describe the relationship of one element or component to another, as illustrated in the figures. Spatially relative terms should be understood to encompass different orientations of elements in use or operation in addition to the orientation depicted in the figures. For example, if an element depicted in the figures is inverted, an element described as "below" or "below" another element may also be positioned "above" the other element. Thus, the exemplary term "below" can encompass both an orientation of below and above. Elements may be oriented in other directions, and thus the spatially relative terms may be interpreted accordingly.

[0027] As used herein, the "planar direction" can be interpreted as the direction perpendicular to the polarizer and / or transparent conductive layer, ie, the direction viewed from the user's viewing side.

[0028] Figure 1 is a diagram showing the stack structure of a light-controlling laminate according to one embodiment of the present invention, Figure 2 is a diagram showing the stack structure of a polarizing plate according to one or more embodiments of the present invention, Figures 3 and 4 are diagrams showing the stack structure of a variable transmittance optical laminate according to one or more embodiments of the present invention, and Figures 5 and 6 are diagrams showing the stack structure of a smart window according to one or more embodiments of the present invention.

[0029] Referring to FIG. 1, a light-controlling stack 100 according to one embodiment of the present invention may include a first polarizer 200-1, a second polarizer 200-2, a first transparent conductive layer 300-1, a second transparent conductive layer 300-2, and a liquid crystal layer 400.

[0030] Referring to FIG. 2, the polarizing plate 200 includes a polarizer 210, and may further include functional layers, such as a protective layer 220, a phase difference adjusting layer 230, and a refractive index adjusting layer 240, on one or both sides of the polarizer 210. For example, the polarizing plate 200 may include a polarizer 210 and a protective layer 220 stacked on one or both sides of the polarizer 210 (see FIGS. 2a and 2b), a polarizer 210, a protective layer 220 stacked on one side of the polarizer 210, and a phase difference adjusting layer 230 stacked on the other side of the polarizer 210 opposite to the one side (see FIG. 2c), a polarizer 210, a protective layer 220 stacked on one side of the polarizer 210, and a phase difference adjusting layer 230 and a refractive index adjusting layer 240 stacked in sequence on the other side of the polarizer 210 opposite to the one side (see FIG. 2d), or a polarizer 210, a protective layer 220 stacked on one side of the polarizer, and a protective layer 220 and a phase difference adjusting layer 230 stacked in sequence on the other side of the polarizer 210 opposite to the one side (see FIG. 2e).

[0031] The polarizer 210 may be a conventional or later developed polarizer, such as a stretched polarizer or a coated polarizer.

[0032] In one embodiment, the stretched polarizer may include a stretched polyvinyl alcohol (PVA)-based resin. The polyvinyl alcohol (PVA)-based resin may be a polyvinyl alcohol-based resin obtained by saponifying a polyvinyl acetate-based resin. Examples of polyvinyl acetate-based resins include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate with other monomers copolymerizable therewith. The other monomers may be unsaturated carboxylic acid-based, unsaturated sulfonic acid-based, olefin-based, vinyl ether-based, or acrylamide-based monomers having an ammonium group. The polyvinyl alcohol (PVA)-based resin may also be modified, such as polyvinyl formal or polyvinyl acetal modified with aldehydes.

[0033] In one embodiment, the coating type polarizer may be formed using a liquid crystal coating composition, which may include a reactive liquid crystal compound and a dichroic dye.

[0034] The reactive liquid crystal compound may refer to a compound that includes, for example, a mesogen skeleton and one or more polymerizable functional groups. Such reactive liquid crystal compounds are known in various ways as reactive mesogens (RMs). The reactive liquid crystal compound can be polymerized by light or heat to form a cured film in which a polymer network is formed while maintaining the liquid crystal alignment.

[0035] The reactive liquid crystal compound may be a monofunctional or polyfunctional reactive liquid crystal compound. The monofunctional reactive liquid crystal compound is a compound having one polymerizable functional group, and the polyfunctional reactive liquid crystal compound is a compound having two or more polymerizable functional groups.

[0036] The dichroic dye is a component contained in the liquid crystal coating composition that imparts polarization properties and has different absorbance in the long axis direction and the short axis direction of the molecule. The dichroic dye may be any conventional or later-developed dichroic dye, for example, one or more selected from the group consisting of azo dyes, anthraquinone dyes, perylene dyes, merocyanine dyes, azomethine dyes, phthaloperylene dyes, indigo dyes, dioxazine dyes, polythiophene dyes, and phenoxazine dyes.

[0037] The liquid crystal coating composition may further include a solvent capable of dissolving the reactive liquid crystal compound and the dichroic dye, such as propylene glycol monomethyl ether acetate (PGMEA), methyl ethyl ketone (MEK), xylene, chloroform, etc. The liquid crystal coating composition may further include a leveling agent, a polymerization initiator, etc., within a range that does not impair the polarization properties of the coating film.

[0038] The protective layer 220 serves to protect the polarization characteristics of the polarizer 210 from post-processing and external environments, and may be implemented in the form of a protective film.

[0039] 2a and 2b, the protective layer 220 may be formed on one or both surfaces of the polarizer 210 in direct contact therewith, but is not limited thereto. For example, the protective layer may be used as a multi-layer structure in which one or more protective layers are continuously stacked, or may be formed on another member in direct contact therewith.

[0040] In one or more embodiments, the protective layer 220 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).

[0041] The phase difference adjusting layer 230 may be formed on one surface of the polarizer 210 in direct contact therewith as shown in Figures 2c and 2d, but is not limited thereto. For example, as shown in Figure 2e, the phase difference adjusting layer 230 may be formed on one surface of the protective layer 220, and the polarizer 210, the protective layer 220, and the phase difference adjusting layer 230 may be sequentially stacked.

[0042] The retardation adjusting layer 230 may be a polymer stretched film obtained by stretching a polymer film that can be given optical anisotropy by stretching in an appropriate manner, or a liquid crystal polymer film.

[0043] In one embodiment, the polymer stretched film may be a polymer layer containing polyolefins such as polyethylene (PE) or polypropylene (PP), cycloolefin polymers (COP) such as polynorbornene, polyesters such as polyvinyl chloride (PVC), polyacrylonitrile (PAN), polysulfone (PSU), acrylic resin, polycarbonate (PC), or polyethylene terephthalate (PET), polyacrylate, cellulose ester polymers such as polyvinyl alcohol (PVA), or triacetyl cellulose (TAC), or a copolymer of two or more monomers forming the polymer.

[0044] The method for obtaining the stretched polymer film is not particularly limited, and can be, for example, by molding the polymer material into a film and then stretching it. The film-forming method is not particularly limited, and 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, and cast molding. Secondary processing methods such as compressed air molding and vacuum forming can also be used. Among these, extrusion molding and cast molding are preferred. In this case, for example, an unstretched film can be extruded using an extruder equipped with a T-die, a circular die, or the like. When 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 the product can be formed through melt-kneading during extrusion molding. Alternatively, an unstretched film can be cast-molded by dissolving various resin components in a solvent common to the various resin components, such as chloroform or methylene dichloride, followed by casting, drying, and solidification.

[0045] The polymer stretched film may be produced by uniaxially stretching the formed film in the mechanical direction (MD; machine direction, lengthwise or longitudinal direction) or uniaxially stretching the formed film in the transverse direction (TD; widthwise or transverse direction) of the mechanical direction. Alternatively, a biaxially stretched film may be produced by stretching the formed film using a method such as sequential biaxial stretching with roll stretching and tenter stretching, simultaneous biaxial stretching with tenter stretching, or biaxial stretching with tubular stretching.

[0046] The liquid crystal polymer film may include a reactive liquid crystal compound in a polymerized state. The reactive liquid crystal compound may be the same as the reactive liquid crystal compound of the coating-type polarizer described above.

[0047] In one or more embodiments, the thickness of the retardation adjusting layer 230 may be 10 μm to 100 μm in the case of a polymer stretched film, and 0.1 μm to 5 μm in the case of a liquid crystal polymer film.

[0048] The refractive index control layer 240 is provided to compensate for the refractive index difference of the optical laminate caused by the transparent conductive layer 300, and may serve to improve visibility by reducing the refractive index difference. The refractive index control layer 240 may also be provided to correct a color caused by the transparent conductive layer 300. Meanwhile, when the transparent conductive layer has a pattern, the refractive index control layer can compensate for the transmittance difference between a patterned region where the pattern is formed and a non-patterned region where the pattern is not formed.

[0049] Specifically, when the transparent conductive layer 300 is stacked adjacent to another member (e.g., a polarizer) having a different refractive index from the transparent conductive layer 300, the difference in refractive index between the adjacent layers may cause a difference in light transmittance, and in particular, when a pattern is formed on the transparent conductive layer, the patterned region and the non-patterned region may be visually distinguishable. Therefore, by including the refractive index control layer, the refractive index is compensated for, thereby reducing the difference in light transmittance of the optical laminate, and in particular, when a pattern is formed on the transparent conductive layer, the patterned region and the non-patterned region may be visually distinguishable.

[0050] In one embodiment, the refractive index of the refractive index adjusting layer 240 may be appropriately selected depending on the material of the adjacent components, and may be preferably 1.4 to 2.6, and more preferably 1.4 to 2.4, in order to prevent light loss due to a sharp difference in refractive index between the transparent conductive layer 300 and other components such as the polarizer 210.

[0051] The refractive index adjustment layer 240 is not particularly limited as long as it can prevent a sharp difference in refractive index between other components such as the polarizer 210 and the transparent conductive layer 300. The refractive index adjustment layer 240 may be formed using a compound used to form a conventional or later-developed refractive index adjustment layer, for example, a refractive index adjustment layer-forming composition containing a polymerizable isocyanurate compound.

[0052] In one embodiment, the polarizing plate 200 may further include other components in addition to the above-mentioned components to support or enhance the properties of the polarizer, for example, an overcoat layer to further improve mechanical durability.

[0053] In one or more embodiments, the polarizing plate 200 may have a thickness of 30 to 200 μm, preferably 30 to 170 μm, and more preferably 50 to 150 μm, which allows the polarizing plate 200 to be manufactured into an optical laminate having a small thickness while maintaining optical properties.

[0054] The transparent conductive layer 300 is provided for driving the liquid crystal layer 400 and may be formed in direct contact with the polarizer 200. For example, as shown in Fig. 1, the first transparent conductive layer 300-1 and the second transparent conductive layer 300-2 may be formed in direct contact with the first polarizer 200-1 and the second polarizer 200-2, respectively.

[0055] Conventional optical laminates used in the manufacture of smart windows and the like are manufactured by forming a conductive layer for driving liquid crystals on one side of a substrate and bonding the other side of the substrate to a polarizer. However, the light control laminate 100 according to the present invention does not require a separate substrate for forming the conductive layer, but instead forms the conductive layer directly on one side of the polarizer, thereby reducing the thickness of the laminate and improving the transmittance and bending characteristics in the light transmission mode.

[0056] In one embodiment, the transparent conductive layer 300 may be formed by direct deposition on one surface of the polarizer 200. In this case, the transparent conductive layer 300 may be formed by directly contacting the pre-treated surface of the polarizer 200 after pre-treating the one surface of the polarizer 200 with a corona treatment or plasma treatment to improve adhesion to the polarizer 200. The pre-treatment is not limited to a corona treatment or a plasma treatment, and any conventional or later-developed pre-treatment process may be used within the scope of the present invention.

[0057] In another embodiment, the transparent conductive layer 300 may be formed in direct contact with the polarizer 200, with an easy-adhesion layer (not shown) provided on one side of the polarizer 200 sandwiched therebetween to improve adhesion to the polarizer 200.

[0058] The transparent conductive layer 300 preferably has a transmittance of 50% or more for visible light, and may include, for example, one or more selected from the group consisting of transparent conductive oxides, metals, carbon-based materials, conductive polymers, conductive inks, and nanowires, but is not limited thereto, and any conventional or later-developed transparent conductive layer material may be used.

[0059] In one or more embodiments, the transparent conductive oxide may include one or more selected from the group consisting of indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), aluminum zinc oxide (AZO), gallium zinc oxide (GZO), fluorine tin oxide (FTO), zinc oxide (ZnO), etc. The metal may include one or more selected from the group consisting of gold (Au), silver (Ag), copper (Cu), aluminum (Al), platinum (Pt), palladium (Pd), chromium (Cr), titanium (Ti), tungsten (W), niobium (Nb), tantalum (Ta), vanadium (V), iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), zinc (Zn), and alloys containing at least one of these metals, such as 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 (CNTs) and graphene, and the conductive polymer may include one or more selected from the group consisting of polypyrrole, polythiophene, polyacetylene, PEDOT, and polyaniline. The conductive ink may be an ink containing a metal powder and a curable polymer binder, and the nanowires may be, for example, silver nanowires (AgNWs).

[0060] The transparent conductive layer 300 may also be formed in a two-layer structure by combining the above materials, for example, a two-layer structure including a metal layer and a transparent conductive oxide layer to reduce the reflectance and increase the transmittance of incident light.

[0061] The liquid crystal layer 400 can change the driving mode of the optical stack by adjusting the transmittance of light incident from one or more directions by an electric field.

[0062] The liquid crystal layer 400 may include a liquid crystal compound and a spacer, and may refer to an area defined by a first alignment film 500-1, a second alignment film 500-2, and a sealant 600, as shown in FIG. 1, for example.

[0063] The liquid crystal compound is not particularly limited as long as it is driven by an electric field and can control the light transmittance, and any conventional or later developed liquid crystal compound may be used. For example, the above-mentioned contents regarding the reactive liquid crystal compound of the coating-type polarizer may equally be applied.

[0064] The liquid crystal behavior mode of the liquid crystal layer 400 is not particularly limited, and for example, as shown in FIG. 1, it may be driven in a TN (Twisted nematic) mode, but is not limited thereto, and may also be driven in an STN (Super twisted nematic) mode, a VA (Vertical alignment) mode, an ECB (Electrically controlled birefringence) mode, etc.

[0065] The spacers may include at least one of ball spacers and column spacers, and are preferably ball spacers. The number of spacers may be one or more, and the height thereof is preferably 1 μm to 10 μm. In addition, the area of ​​the spacers in the liquid crystal layer 400 in the planar direction is preferably 0.01 to 10% of the area of ​​the liquid crystal layer 400 in terms of improving user visibility and transmittance in the transmission mode.

[0066] In one embodiment, the liquid crystal layer 400 may further include an alignment film 500 if necessary, for example, formed on both sides of the liquid crystal layer 400 containing a liquid crystal compound.

[0067] The alignment film 500 is not particularly limited as long as it can impart alignment to the dispersed liquid crystal, and preferably includes a photoalignable or photocurable polymer, etc. For example, the alignment film 500 can be fabricated by applying and curing an alignment film coating composition including a photoalignable or photocurable polymer, a photopolymerization initiator, and a solvent.

[0068] The photo-alignable or photo-curable polymer is not particularly limited, and may be a cinnamate-based polymer, a polyimide-based polymer, or the like, such as poly(vinyl cinnamate) (PVCi), poly(siloxane cinnamate) (PSCN), poly(ω(4-chalconyloxy)alkoxyphenylmaleimide), 6-FDA-HAB-Cl, or any other conventional or later-developed polymer capable of exhibiting alignment.

[0069] The sealant 600 is positioned between the first polarizer 200-1 and the second polarizer 200-2 in the inactive area to bond the first polarizer and the second polarizer, and may be provided together with the spacer to secure a space for the liquid crystal layer 400 to be provided between the first polarizer 200-1 and the second polarizer 200-2.

[0070] The sealant 600 may include a curable resin as a base resin. The base resin may be a UV-curable resin or a thermosetting resin known in the art for use in sealants. The UV-curable resin may be a polymer of a UV-curable monomer. The thermosetting resin may be a polymer of a thermosetting monomer.

[0071] The base resin of the sealant 600 may be, for example, an acrylate-based resin, an epoxy-based resin, a urethane-based resin, a phenol-based resin, or a mixture of these resins. In one embodiment, the base resin may be an acrylate-based resin, and the acrylate-based resin may be a polymer of an acrylic monomer. The acrylic monomer may be, for example, a multifunctional acrylate. In another embodiment, the sealant may further include a monomer component in the base resin. The monomer component may be, for example, a monofunctional acrylate. In this specification, a monofunctional acrylate may refer to a compound having one acrylic group, and a multifunctional acrylate may refer to a compound having two or more acrylic groups. The curable resin may be cured by ultraviolet irradiation and / or heating. The ultraviolet irradiation conditions or heating conditions may be appropriately set within a range that does not impair the objectives of the present application. The sealant may further include an initiator, for example, a photoinitiator or a thermal initiator, if necessary.

[0072] The sealant 600 may be formed by a method commonly used in the art, for example, by drawing the sealant onto the outer periphery (i.e., non-active area) of the liquid crystal layer using a dispenser equipped with a nozzle.

[0073] Referring to FIG. 3, a variable transmittance optical stack according to one embodiment of the present invention may include a light-controlling stack 100 and surface protection films 700 formed on both sides of the light-controlling stack.

[0074] The surface protective film 700 may be provided for the purpose of preventing scratches, contamination, corrosion, etc. on the surface that may occur during the manufacturing, transportation, or storage of the light control laminate 100, and may be peeled off and removed from the light control laminate 100 before glass such as vehicle glass 910 or building glass 920 is attached to the light control laminate 100 (see FIG. 5).

[0075] The surface protection film 700 preferably has a peel strength from the light-control laminate of 1.0 N / 25 mm to 2.4 N / 25 mm. The peel strength may be measured using a universal testing machine as a 180° peel strength (N / 25 mm) between the light-control laminate 100 and the surface protection film at a speed of 300 mm / min. When the peel strength of the surface protection film satisfies this range, air bubbles do not enter the optical laminate or the sealant is not damaged during the manufacture of the light-control laminate 100 or the peeling of the surface protection film 700, and the durability of the optical laminate may be further improved.

[0076] The surface protection film 700 may include a base film and an adhesive layer formed on the base film.

[0077] The substrate film may be a conventional or later-developed substrate film, and may include, for example, one or more selected from the group consisting of polyolefin-based films, polyester-based films, acrylic-based films, styrene-based films, amide-based films, polyvinyl chloride-based films, polyvinylidene chloride-based films, and polycarbonate-based films. The thickness of the substrate film may be 10 μm to 300 μm, taking into consideration the possibility of deformation during the production, transportation, or storage of the light control laminate 100, and the ease of attachment to the light control laminate 100.

[0078] The adhesive layer may be formed using an adhesive, and preferably has appropriate adhesive strength so that when the surface protection film 700 is peeled off, only the surface protection film 700 is removed cleanly from the light-control laminate 100 without affecting other components such as the sealant, as well as transparency and thermal stability.

[0079] The pressure-sensitive adhesive may be a conventional or later-developed pressure-sensitive adhesive, and in one or more embodiments, may be an acrylic pressure-sensitive adhesive, a rubber pressure-sensitive adhesive, a silicone pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, a polyvinyl alcohol pressure-sensitive adhesive, a polyvinylpyrrolidone pressure-sensitive adhesive, a polyacrylamide pressure-sensitive adhesive, a cellulose pressure-sensitive adhesive, a vinyl alkyl ether pressure-sensitive adhesive, etc. The pressure-sensitive adhesive is not particularly limited as long as it has adhesive strength and viscoelasticity, but from the viewpoint of availability, etc., it may preferably be an acrylic pressure-sensitive adhesive, which may contain, for example, a (meth)acrylate copolymer, a crosslinking agent, and a solvent.

[0080] The crosslinking agent may be a conventional or later developed crosslinking agent, and may include, for example, a polyisocyanate compound, an epoxy resin, a melamine resin, a urea resin, a dialdehyde, a methylol polymer, or the like, and preferably includes a polyisocyanate compound.

[0081] The solvent may include conventional solvents used in the field of resin compositions, such as alcohol-based compounds such as methanol, ethanol, isopropanol, butanol, and propylene glycol methoxy alcohol; 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 methoxy acetate; cellosolve-based compounds such as methyl cellosolve, ethyl cellosolve, and propyl cellosolve; and hydrocarbon-based compounds such as hexane, heptane, benzene, toluene, and xylene. These may be used alone or in combination of two or more.

[0082] The thickness of the adhesive layer 400 may be appropriately determined depending on the type of resin acting as the adhesive, adhesive strength, the environment in which the adhesive is used, etc. In one embodiment, the adhesive layer may have a thickness of 1 μm to 30 μm so that the peel strength of the surface protection film 700 is 1.0 N / 25 mm to 2.4 N / 25 mm.

[0083] Referring to FIG. 4, a variable transmittance optical stack according to another embodiment of the present invention may include a photochromic stack 100 and a hard coating layer 800 formed on both sides of the photochromic stack.

[0084] The hard coating layer 800 may be provided to protect components such as the polarizer, the variable transmittance layer, and the light-controlling stack from external physical and chemical impacts, and in terms of protecting the light-controlling stack 100 from the external environment, it can perform substantially the same function as the surface protective layer 700. Therefore, when the variable transmittance optical stack of the present invention includes the hard coating layer 800, it may not include the surface protective film 700 (see FIGS. 4 and 6).

[0085] To protect the light-control laminate 100 from the external environment, the hard coating layer 800 preferably has a surface pencil hardness of HB to 6H. The surface pencil hardness may be measured by applying a 500 g load using a pencil hardness tester (manufactured by SUKBO Science Co., Ltd., Korea) to measure the pencil hardness of the hard coating layer. The pencil may be a Mitsubishi product, and the test may be repeated five times per pencil hardness, followed by heat treatment at 100°C for 10 minutes, and evaluated based on whether scratches are visually observed. When the surface pencil hardness of the hard coating layer satisfies the above range, the hard coating layer has excellent abrasion resistance, thereby preventing surface defects in subsequent processes.

[0086] The hard coating layer 800 may be a conventional or later-developed hard coating layer, and may be formed from a hard coating composition including, for example, an acrylate- or epoxy-based compound, inorganic fine particles, and / or a photoinitiator. The acrylate-based compound may include a monomer or oligomer containing a (meth)acrylate group, and the term "(meth)acryl-" as used herein refers to "methacryl-," "acryl-," or both. Non-limiting examples of the acrylate compound include neopentyl glycol acrylate, 1,6-hexanediol (meth)acrylate, propylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, 1,2,4-cyclohexane tetra(meth)acrylate, pentaglycerol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, and dipentaerythritol tri(meth)acrylate. acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol tri(meth)acrylate, tripentaerythritol hexatri(meth)acrylate, bis(2-hydroxyethyl)isocyanurate di(meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, isooctyl (meth)acrylate, isodecyl (meth)acrylate, stearyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, phenoxyethyl (meth)acrylate, isobornyl (meth)acrylate, etc. These may be used alone or in combination of two or more.The acrylate compound may include an epoxy (meth)acrylate compound and / or a urethane (meth)acrylate compound. The epoxy compound may also include a monomer or oligomer having at least one epoxy group in the molecule. The epoxy group may be an alicyclic epoxy group. The alicyclic ring contained in the epoxy group may have 3 to 7 carbon atoms, for example, an alicyclic epoxy group containing a cyclohexane ring (cyclohexyl epoxy). The alicyclic ring may have a substituent. For example, the alicyclic ring may include an alkyl substituent having 1 to 20 carbon atoms. If the alkyl substituent has more than 20 carbon atoms, the curing speed may be reduced. The alkyl substituent may be linear or branched, and if branched, the alkyl substituent may have 3 or more carbon atoms.

[0087] According to one embodiment of the present invention, in a method for manufacturing a hard coating film, the hard coating composition includes inorganic fine particles. The inorganic fine particles may be nano-sized particles, such as particles of 100 nm or less, 10 to 100 nm, or 10 to 50 nm. Furthermore, the inorganic fine particles may be, for example, silica fine particles, aluminum oxide particles, titanium oxide particles, or zinc oxide particles.

[0088] The inclusion of the inorganic fine particles can further improve the hardness of the hard coating layer. According to one embodiment of the present invention, the inorganic fine particles may be included in an amount of 10 to 60 parts by weight or 20 to 50 parts by weight, based on 100 parts by weight of the hard coating composition. By including the inorganic fine particles in this range, the hardness of the hard coating layer can be improved without deteriorating the physical properties of the hard coating composition.

[0089] In one embodiment of the present invention, in a method for manufacturing a hard coating film, the hard coating composition includes a photoinitiator, such as, but not limited to, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1-propanone, methylbenzoyl formate, α,α-dimethoxy-α-phenylacetophenone, 2-benzoyl-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, or bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide. Currently available commercial products include Irgacure 184, Irgacure 500, Irgacure 651, Irgacure 369, Irgacure 907, Darocur 1173, Darocur MBF, Irgacure 819, Darocur TPO, Irgacure 907, Esacure KIP 100F, etc. These photoinitiators may be used alone or in combination of two or more different types.

[0090] According to one embodiment of the present invention, the photoinitiator may be included in an amount of 0.5 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the hard coating composition. When the photoinitiator is included in this range, sufficient cross-linking photopolymerization can be achieved without deteriorating the physical properties of the hard coating layer.

[0091] Meanwhile, in the method for producing a hard coating film according to the present invention, the hard coating composition may further contain additives commonly used in the technical field to which the present invention pertains, such as a surfactant, an anti-yellowing agent, a leveling agent, or an antifouling agent, in addition to the above-mentioned components. The content of the additives is not particularly limited, as it can be adjusted in various ways within a range that does not deteriorate the physical properties of the hard coating composition according to the present invention.

[0092] In one or more embodiments, the thickness of the hard coating layer 800 may be 1 μm to 50 μm, preferably more than 2 μm and less than 23 μm, and more preferably 3 μm to 20 μm. The thickness may refer to the thickness after drying, and when the thickness of the hard coating layer 800 satisfies the above range, it is advantageous in terms of not only excellent flex resistance and durability but also the possibility of thinning.

[0093] 3 illustrates an example in which the surface protection film 700 is formed on both sides of the light control stack 100, and FIG. 4 illustrates an example in which the hard coating layer 800 is formed on both sides of the light control stack, but the present invention is not necessarily limited to this. For example, a variable transmittance optical stack according to another embodiment of the present invention may include a light control stack; a surface protection film formed on one side of the light control stack; and a hard coating layer formed on the other side of the light control stack opposite the one side.

[0094] In addition to the variable transmittance optical laminate, the present invention also includes a smart window including the same, a vehicle in which the smart window is applied to at least one of a front window, a rear window, a side window, a sunroof window, and an interior partition, and a building fixture including the smart window.

[0095] For example, an automobile including the smart window of the present invention may be one in which vehicle glass 910 is bonded to both sides of the variable transmittance optical laminate from which the surface protection film 700 has been peeled (see FIG. 5a), or one in which vehicle glass 910 is bonded to both sides of the variable transmittance optical laminate including the hard coating layer 800 (see FIG. 6a). For example, the smart window including the vehicle glass may be manufactured by placing adhesive films and vehicle glass on both sides of the optical laminate, and then heating them at a temperature of 90°C and a vacuum of about 1 bar for 10 to 20 minutes using a press machine, and the adhesive films may include EVA film, PVB film, etc.

[0096] In addition, the variable transmittance optical laminate may have building fixtures (glass for fixtures) 920 bonded to both sides or one side thereof, or may have fixture glass applied to both sides of the optical laminate and bonded thereto, followed by UV curing to produce a smart window product for fixtures having the same configuration as that shown in Figures 5b and 6b, or may have fixture glass bonded to one side of the optical laminate using a lamination method to produce a smart window product for fixtures having the same configuration as that shown in Figures 5c and 6c. [Example]

[0097] Hereinafter, specific examples of the present invention will be described. However, the present invention is not limited to the examples disclosed below, and may be embodied in various different forms. However, these examples are provided to fully disclose the present invention and to fully convey the scope of the invention to those skilled in the art. The present invention is defined only by the scope of the claims.

[0098] Manufacturing Example 1: Manufacturing of polarizing plates (1) Swelling treatment process A 60 μm thick polyvinyl alcohol film (raw film) (manufactured by Kuraray Co., Ltd., product name "Kuraray Poval Film VF-PE#6000", average polymerization degree 2400, saponification degree 99.9 mol%) was continuously unwound from a raw roll and transported, and immersed in a swelling bath containing pure water at 20°C for 30 seconds. In this swelling treatment process, inter-roll stretching (longitudinal uniaxial stretching) was performed with a difference in peripheral speed between the nip rolls. The stretching ratio based on the raw film was 2.5 times.

[0099] (2) Dyeing process Next, the film passed through the nip rolls was immersed in a dye bath containing pure water / potassium iodide / iodine / boric acid (mass ratio) of 100 / 2 / 0.01 / 0.3 at 30°C for 120 seconds. During this dyeing process, roll-to-roll stretching (longitudinal uniaxial stretching) was performed with a difference in peripheral speed between the nip rolls. The stretching ratio was 1.1 times, based on the film after the swelling treatment step.

[0100] (3) Crosslinking process Next, the film that passed through the nip rolls was immersed in a first crosslinking bath at 56°C containing pure water / potassium iodide / boric acid (mass ratio) of 100 / 12 / 4 for 70 seconds. Roll-to-roll stretching (longitudinal uniaxial stretching) was performed with a difference in peripheral speed between the nip rolls and a nip roll installed between the first and second crosslinking baths. The stretching ratio was 1.9 times, based on the film after the dyeing treatment process.

[0101] (4) Complementary color processing process Next, the film after the crosslinking treatment was immersed for 10 seconds in a second crosslinking bath at 40° C. containing potassium iodide / boric acid / pure water (mass ratio) of 9 / 2.9 / 100.

[0102] (5) Cleaning process Next, the film after the second crosslinking treatment was immersed in a cleaning bath containing pure water at 14°C for 5 seconds, and the shower volume was 5 m 3 Washing was performed at 14°C for 1 hour and a shower temperature of 14°C.

[0103] (6) Drying process The washed film was then passed through a drying oven and heated and dried at 80°C for 190 seconds to produce a polarizer film. The moisture content after drying was 13.6%, and the thickness of the resulting polarizer film was approximately 21µm.

[0104] (7) Bonding process Next, a water-based adhesive containing 5 parts by weight of polyvinyl alcohol per 100 parts by weight of water was prepared as the adhesive. Then, a first triacetyl cellulose (TAC) protective film (60 μm) and a second triacetyl cellulose (TAC) protective film (40 μm) were laminated on both sides of the polarizer film using the prepared UV adhesive. The resulting laminate was exposed to UV light to cure the adhesive, producing a polarizing film. The thickness of the adhesive layer in the resulting polarizing film was approximately 2 μm.

[0105] Preparation Example 2: Preparation of hard coating composition A hard coating composition was prepared by mixing 16.2 g of a dendrimer compound (Miwan Specialty Chemical Co., Ltd., SP-1106), 14.4 g of inorganic nanoparticles (10 to 20 nm, silica particles: 50 wt %, solvent: methyl ethyl ketone (MEK)), 1.8 g of a polyfunctional (meth)acrylate compound containing an ethylene glycol group, 0.7 g of a photoinitiator (1-hydroxycyclohexylphenyl ketone), and 2.9 g of methyl ethyl ketone.

[0106] Manufacturing Example 3: Manufacturing of hard coating layer (HC2) The hard coating composition prepared in Preparation Example 2 was dried on one side of the second triacetyl cellulose (TAC) protective film (thickness: 40 μm) of the polarizing plate, and then bar-coated to a desired thickness using a Mayer bar. After drying at 80°C for 5 minutes, the hard coating composition was applied with a high-pressure mercury lamp at 500 mJ / cm. 2A polarizing plate was fabricated with a hard coating layer (HC2) formed on the entire surface by curing with a light intensity of 10 ...

[0107] Manufacturing Example 4: Manufacturing of Surface Protection Film (PF) A surface protection film (LGC, LDM-EPCB) was used to laminate a 20 μm thick adhesive layer and a 38 μm thick PET film on the opposite side of the hard coating layer (HC2) of the polarizer prepared in Preparation Example 3, to prepare a polarizer with a surface protection film attached.

[0108] Manufacturing Example 5: Manufacturing of transparent conductive layer (ITO / IML) A polarizer with the surface protection film of Preparation Example 4 was placed inside the sputtering gun, and 450 W DC power was applied. Plasma was then induced on an ITO (10 wt% Sn-doped In2O3) target to form a transparent conductive layer (90 nm) on one side of the hard coating layer (HC2), producing a first conductive laminate and a second conductive laminate with a laminate structure of surface protection film / polarizer / hard coating layer / transparent conductive layer. The transparent conductive layer was then ion-treated using an ion source with 50 W DC power. The fabrication was carried out at room temperature under a pressure of 3 mTorr, with argon gas and oxygen gas supplied at 30 sccm and 1 sccm, respectively. ITO performance was measured by measuring ITO thickness using a FT-SEM and ITO surface resistance (Ω / □) using a four-point probe.

[0109] Production Example 6: Production of alignment film An alignment liquid was coated on the transparent conductive layer (ITO / IML) surface of each of the first and second conductive laminates prepared in Preparation Example 5, and then dried (80°C / 2 minutes). Then, an alignment film was formed by irradiating UV onto the dried alignment liquid, thereby preparing an upper laminate and a lower laminate, each having a layered structure of surface protection film / polarizer / hard coating layer / transparent conductive layer / alignment film.

[0110] Manufacturing Example 7: Manufacturing of ball spacer scattering The mixed solvent was prepared by mixing 0.03 g of ball spacers (SP series, manufactured by SEKISUI Corporation) with 100 ml of IPA. The lower laminate of Preparation Example 6 was then placed in a spacer sprayer (SDSS-KHU02, SHINDO ENG LAB), and the prepared mixed solvent was sprayed at 110°C. After drying for 20 minutes, ball spacers were formed on the alignment layer of the lower laminate of Preparation Example 6.

[0111] Manufacturing Example 8: Manufacturing of variable transmittance optical laminate Using a sealant dispenser (SHOTmini 200Ωx, manufactured by MUSASHI), sealant (UVF-006, 70,000 mPa·s, manufactured by SEKISUI) was applied to the transparent conductive layer (ITO / IML) of the lower laminate on which the ball spacers were formed according to Preparation Example 7 using a sharp needle (SPN-0.25-12.7L) at a discharge pressure of 200 mPa according to the product size drawing, and liquid crystal was injected onto the alignment film using the ODF (One Drop Filling) process. Then, with the polarization axes of the polarizers provided in the upper laminate and the lower laminate of Preparation Example 6 aligned parallel to each other at 0° or 90°, a liquid crystal was injected at a density of 3 kg / cm. 2 The sheets were bonded under pressure to produce a variable transmittance optical laminate for smart windows.

[0112] Examples and Comparative Examples Example 1 The variable transmittance optical laminate of Example 1 was manufactured according to the above Manufacturing Examples 1 to 8.

[0113] Example 2 A variable transmittance optical laminate of Example 2 was produced in the same manner as in Example 1, except that the surface protective film (manufactured by Fujimori Co., Ltd., AY-638) used in Production Example 4 was used.

[0114] Example 3 A variable transmittance optical laminate of Example 3 was manufactured in the same manner as in Example 1, except that a hard coating layer (HC1) was manufactured instead of the surface protective film in Preparation Example 4. The hard coating layer (HC1) was manufactured to a thickness of 3 μm using a Mayer bar, and the manufacturing method was the same as in Preparation Example 3.

[0115] Example 4 A variable transmittance optical laminate of Example 4 was manufactured in the same manner as in Example 1, except that a hard coating layer (HC1) was manufactured instead of the surface protective film in Preparation Example 4. The hard coating layer (HC1) was manufactured to a thickness of 20 μm using a Mayer bar, and the manufacturing method was the same as in Preparation Example 3.

[0116] Comparative Example 1 A variable transmittance optical laminate of Comparative Example 1 was produced in the same manner as in Example 1, except that in Production Example 4 a surface protection film (LDM-EPHC, manufactured by LGC) was used.

[0117] Comparative Example 2 A variable transmittance optical laminate of Comparative Example 2 was produced in the same manner as in Example 1, except that the surface protective film (manufactured by Fujimori Co., Ltd., AS3-501) used in Production Example 4 was used.

[0118] Comparative Example 3 A variable transmittance optical laminate of Comparative Example 3 was manufactured in the same manner as in Example 1, except that a hard coating layer (HC1) was manufactured instead of the surface protection film in Preparation Example 4. The hard coating layer (HC1) was prepared to a thickness of 2 μm using a Mayer bar, and the preparation method was the same as in Preparation Example 3.

[0119] Comparative Example 4 A variable transmittance optical laminate of Comparative Example 4 was manufactured in the same manner as in Example 1, except that a hard coating layer (HC1) was manufactured instead of the surface protection film in Manufacturing Example 4. The hard coating layer (HC1) was manufactured to a thickness of 23 μm using a Mayer bar, and the manufacturing method was the same as in Manufacturing Example 3.

[0120] Experimental Example (1) Evaluation of peel strength The variable transmittance optical laminates of Examples 1 and 2 and Comparative Examples 1 and 2 were cut into 25mm x 250mm pieces using a super cutter and then bonded to adhesive glass plates to prepare specimens. The prepared specimens were fixed to a universal testing machine, and the 180° peel force (N / 25mm) between the light-control laminate and the surface protection film was measured at a speed of 300mm / min. The measurement results are shown in Tables 1 and 2 below.

[0121] (2) Apparent reliability evaluation For the optical laminates of Examples 1 and 2 and Comparative Examples 1 and 2, the surface protective films were peeled off from both sides of a 38-inch (800 x 500 mm) optical laminate using the method described in Korean Patent Publication No. 10-2013-0060879, and then the presence or absence of sealant breakage and bubble formation was checked. The evaluation results are shown in Tables 1 and 2 below. <Evaluation criteria> ○: Evaluation result: Good (no sealant breakage or air bubbles within the LCD area) X: Evaluation result: Poor (bubbles occurred in the adhesive layer during ITO deposition or the sealant did not break or bubbles occurred during peeling)

[0122] (3) Measurement of the thickness of the hard coating layer (HC1) For the optical laminates of Examples 3 and 4 and Comparative Examples 3 and 4, a thickness meter (MH-15M, manufactured by Sendai Nikon Co., Ltd.) was used to measure the thickness of the polarizing plate after and before the hard coating layer (HC1) was formed, and the difference between the two thicknesses was calculated to calculate the thickness of the hard coating layer (HC1). The measurement results are shown in Tables 1 and 2 below.

[0123] (4) Evaluation of surface pencil hardness The surface pencil hardness of the hard coating surface of the optical laminates of Examples 3 and 4 and Comparative Examples 3 and 4 was measured using a pencil hardness tester (manufactured by SUKBO Science Co., Ltd., Korea) with a load of 500 g. The pencil was a Mitsubishi product, and five tests were performed for each pencil hardness. The samples were then heat-treated at 100°C for 10 minutes, and the presence of scratches was visually confirmed. The evaluation results are shown in Tables 1 and 2 below.

[0124] (5) Steel wool test The optical laminates of Examples 3 and 4 and Comparative Examples 3 and 4 were subjected to abrasion resistance tests on the hard coating surfaces of the optical laminates using a steel wool tester (WT-LCM100, manufactured by Protec Co., Ltd., Korea) by reciprocating 10 times at a speed of 100 mm / sec under a load of 1 kg / (2 cm x 2 cm). The steel wool used was #0000. The evaluation results are shown in Tables 1 and 2 below. <Evaluation criteria> ○: 0 scratches, no discoloration △: 1 to 10 scratches, no discoloration X: More than 10 scratches, discoloration confirmed (visual)

[0125] (6) Reliability mandrel evaluation To evaluate the bending properties and crack susceptibility of the optical laminates of Examples 3 and 4 and Comparative Examples 3 and 4 using a cylindrical bending tester (Lab-QD605, manufactured by CKSI), a 100x100mm sample specimen with upper and lower plates bonded together was placed on a 32mm diameter steel rod so that the lower plate surface of the polarizer was in contact with the steel rod. In the bent state, a 1kg load was applied to the outside of the bent area, and the sample was placed in a 90°C oven for 2 hours. After that, the sample was placed at room temperature and the bent area was observed to check for the presence or absence of cracks. The evaluation results are shown in Tables 1 and 2 below. <Evaluation criteria> ○: 0 cracks X: 1 or more cracks

[0126] [Table 1]

[0127] [Table 2]

[0128] Referring to Tables 1 and 2 above, in Examples 1 and 2, where the peel strength of the surface protection film was 1.0 N / 25 mm to 2.4 N / 25 mm, respectively, the apparent reliability evaluation results showed that there was no sealant breakage or air bubbles within the LCD area after the surface protection film was peeled. On the other hand, in Comparative Examples 1 and 2, where the peel strength of the surface protection film was 0.7 N / 25 mm and 2.6 N / 25 mm, respectively, which was outside the range of 1.0 N / 25 mm to 2.4 N / 25 mm, air bubbles were generated at the adhesion interface of the surface protection film during ITO deposition, or the sealant did not break or air bubbles were generated during peeling.

[0129] In contrast, in Examples 3 and 4, where the surface pencil hardness of the hard coating layer was HB to 6H, the steel wool test results showed that the hard coating layer had excellent abrasion resistance, and the reliability mandrel test showed excellent bending properties with no cracking.In contrast, in Comparative Examples 3 and 4, where the surface pencil hardness of the hard coating layer was B and 7H, respectively, which was outside the HB to 6H range, the steel wool test results and reliability mandrel test results for the Examples were poor.

[0130] Therefore, when the peel strength of the surface protection film included in the optical laminate is 1.0 N / 25 mm to 2.4 N / 25 mm, damage to the sealant and the intrusion of air bubbles into the liquid crystal can be prevented when the surface protection film is peeled off. Even if the optical laminate does not include the surface protection film, when the optical laminate includes a hard coating layer having a surface pencil hardness of HB to 6H, it is possible to provide an optical laminate that has excellent abrasion resistance and bending properties and can protect the polarizing plate from the external environment. [Industrial Applicability]

[0131] According to an optical laminate according to an embodiment of the present invention, the peeling force of the surface protection film is optimized, and damage to the sealant and the intrusion of air bubbles into the liquid crystal can be prevented when the surface protection film is peeled off. [Explanation of symbols]

[0132] 100: Light-controlling laminate 200: Polarizing plate 210: Polarizer 220:Protective layer 230: Phase difference adjustment layer 240: Refractive index adjusting layer 300: Transparent conductive layer 400: Liquid crystal layer 500: Alignment film 600: Sealant 700: Surface protection film 800: Hard coating layer 910: Vehicle glass 920: Glass for building materials

Claims

1. A first polarizing plate, a first transparent conductive layer formed on one surface of the first polarizing plate; a second polarizing plate facing the first polarizing plate; a second transparent conductive layer formed on one surface of the second polarizer and facing the first transparent conductive layer; and a light-controlling laminate including a liquid crystal layer provided between the first transparent conductive layer and the second transparent conductive layer; The following (i) or (ii): (i) a hard coating layer is provided on one surface of the light-controlling laminate, and a surface protective film is provided on the other surface of the light-controlling laminate opposite to the one surface; (ii) a surface protective film is provided on both sides of the light-controlling laminate; Fulfilling At least one of the first transparent conductive layer and the second transparent conductive layer is formed in direct contact with one of the first polarizer and the second polarizer, the surface protection film has a 180° peel strength measured at a speed of 300 mm / min of 1.0 N / 25 mm to 2.4 N / 25 mm; The hard coating layer has a surface pencil hardness of HB to 6H.

2. The variable transmittance optical laminate according to claim 1 , wherein the surface protection film includes a substrate film and an adhesive layer formed on the substrate film, and is laminated on the light control laminate via the adhesive layer.

3. 3. The variable transmittance optical laminate according to claim 2, wherein the substrate film comprises at least one film selected from the group consisting of polyolefin-based films, polyester-based films, acrylic-based films, styrene-based films, amide-based films, polyvinyl chloride-based films, polyvinylidene chloride-based films, and polycarbonate-based films.

4. The variable transmittance optical laminate according to claim 2 , wherein the substrate film has a thickness of 10 μm to 300 μm.

5. The variable transmittance optical stack of claim 2 , wherein the adhesive layer has a thickness of 1 μm to 30 μm.

6. The variable transmittance optical laminate according to claim 1 , wherein when the surface protection film is peeled off from the light-control laminate, the liquid crystal layer is not broken and no air bubbles are generated.

7. The variable transmittance optical laminate according to claim 1 , wherein the hard coating layer comprises at least one compound selected from the group consisting of an acrylate-based compound and an epoxy compound.

8. The variable transmittance optical stack of claim 1 , wherein the hard coating layer has a thickness of 1 μm to 50 μm.

9. 2. The variable transmittance optical laminate of claim 1, wherein at least one of the first and second transparent conductive layers comprises at least one selected from the group consisting of transparent conductive oxides, metals, carbon-based materials, conductive polymers, conductive inks, and nanowires.

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

11. The variable transmittance optical laminate according to claim 1 , wherein at least one of the first polarizer and the second polarizer has a thickness of 30 μm to 200 μm.

12. The variable transmittance optical laminate according to claim 1, wherein the liquid crystal layer comprises one or more spacers selected from the group consisting of ball spacers and column spacers.

13. The variable transmittance optical stack of claim 12 , wherein the spacer has a height of 1 μm to 10 μm.

14. The variable transmittance optical laminate according to claim 12, wherein the area of ​​the spacer in the liquid crystal layer is 0.01% to 10% of the area of ​​the liquid crystal layer.

15. The variable transmittance optical stack according to claim 1 , further comprising alignment films on both sides of the liquid crystal layer.

16. A smart window comprising the variable transmittance optical stack of any one of claims 1 to 15.

17. 17. A means of transportation comprising the smart window of claim 16.

18. 17. A car in which the smart window according to claim 16 is applied to at least one of a front window, a rear window, a side window, a sunroof window, and an interior partition.

19. A wearable device comprising the smart window of claim 16.

20. Architectural fittings comprising the smart window of claim 16.

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