Transmittance variable optical laminate, method for producing the same, and smart window including the same

Abstract

The present invention relates to a transmissivity variable optical laminate and a method for manufacturing the same, and a smart window including the same, the transmissivity variable optical laminate including: a first laminate in which a first polarizing plate, a first transparent conductive layer, and a first alignment film are laminated in this order; a second laminate in which a second polarizing plate, a second transparent conductive layer, and a second alignment film are laminated in this order; and a dispersed liquid crystal disposed between the first laminate and the second laminate, the dispersed liquid crystal including spacers, a ratio of a compression elastic modulus of the spacers to a compression elastic modulus of any one of the first laminate and the second laminate being from 0.75 to 1.55, and the spacers being included in an amount of from 0.5 to 3.0% by weight based on a total weight of the dispersed liquid crystal.

Description

Technical Field

[0001] The present invention relates to a variable transmittance optical laminate, a method for manufacturing the same, and a smart window including the same.

Background Art

[0002] Generally, an external light blocking coating is often applied to the glass window of a moving means such as a vehicle. However, the glass window of a conventional moving means has a fixed transmittance, and the external light blocking coating also has a fixed transmittance. Therefore, the overall transmittance of such a conventional window of a moving means is fixed, which may induce an accident. For example, when the overall transmittance is set low, there is no problem during the daytime when there is sufficient light around, but in the case of nighttime when there is not enough light around, there is only the problem that it is difficult for a driver or the like to properly check the surroundings of the moving means. Or when the overall transmittance is set high, there is a problem that it may cause glare to a driver or the like during the daytime when there is sufficient light around. Thus, a variable transmittance optical laminate capable of changing the light transmittance when a voltage is applied thereto has been developed.

[0003] The variable transmittance optical laminate is driven by driving liquid crystal by applying a voltage to vary the transmittance. However, the variable transmittance optical laminate developed so far is manufactured by forming a conductive layer for driving the liquid crystal on a separate base material and then combining this with other elements such as a polarizing plate.

[0004] Korean Registered Patent Publication No. 10-2226630 discloses a dimming film that sandwiches and supports a liquid crystal layer by first and second laminates each having an alignment film, and controls the alignment of liquid crystal molecules related to the liquid crystal layer by driving electrodes provided on the first and second laminates to control transmitted light. In the dimming film, a spacer for maintaining the thickness of the liquid crystal layer is provided, the Vickers hardness value Xs of the spacer is 16.9 or more and 40.2 or less, and the Vickers hardness value Xf of the second laminate is 11.8 or more and 35.9 or less, a laminated glass, and a method for manufacturing the dimming film.

[0005] However, relying solely on the individual hardness ranges of the laminate and the spacer has a problem in that defects may occur due to the correlation between the hardness of the laminate and the spacer even within the same numerical range, which may consequently cause critical problems in the durability and quality of the device.

[0006] Therefore, it is necessary to develop a transmissivity-variable optical laminate with excellent durability that can clarify the correlation between the compression elastic moduli of the laminate and the spacer, suppress interference between the respective base materials, prevent the occurrence of cracks or scratches, and maintain a uniform liquid crystal gap.

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] An object of the present invention is to solve the above-described problems by including a spacer in a dispersed liquid crystal disposed between a first laminate and a second laminate, wherein the ratio of the compression elastic modulus of the spacer to the compression elastic modulus of either one of the first laminate and the second laminate is 0.75 to 1.55, and the spacer content with respect to the total weight of the dispersed liquid crystal is 0.5 to 3.0% by weight.

[0008] Furthermore, an object of the present invention is to prevent cracks from occurring in the optical laminate. Furthermore, an object of the present invention is to ensure a liquid crystal space between the laminates and enable smooth light transmission.

[0009] However, the problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned should be clearly understood by those skilled in the art from the following description.

MEANS FOR SOLVING THE PROBLEMS

[0010] The present invention relates to a transmissivity variable optical laminate including a first laminate formed by laminating a first polarizing plate, a first transparent conductive layer, and a first alignment film in this order, a second laminate formed by laminating a second polarizing plate, a second transparent conductive layer, and a second alignment film in this order, and a dispersed liquid crystal disposed between the first laminate and the second laminate, wherein the dispersed liquid crystal includes spacers, and a ratio of a compression elastic modulus of the spacers to a compression elastic modulus of either one of the first laminate and the second laminate is 0.75 to 1.55, and the spacers are included in an amount of 0.5 to 3.0% by weight based on a total weight of the dispersed liquid crystal.

[0011] In a first aspect of the present invention, the compression elastic modulus of either one of the first laminate and the second laminate may be 3,000 to 4,000 Mpa.

[0012] In a second aspect of the present invention, the compression elastic modulus of the spacers may be 2,000 to 5,500 Mpa.

[0013] In a third aspect of the present invention, the spacers may include one or more selected from the group consisting of ball spacers and column spacers.

[0014] In a fourth aspect of the present invention, at least one of the first transparent conductive layer and the second transparent conductive layer may be formed in direct contact with one of the first polarizing plate and the second polarizing plate.

[0015] In a fifth aspect of the present invention, at least one of the first transparent conductive layer and the second transparent conductive layer may include one or more selected from the group consisting of transparent conductive oxides, metals, carbon-based substances, conductive polymers, conductive inks, and nanowires.

[0016] In a sixth aspect of the present invention, at least one of the first polarizing plate and the second polarizing plate may include one or more selected from the group consisting of a functional coating layer, a protective layer, a retardation adjusting layer, a refractive index adjusting layer, and an overcoat layer.

[0017] In a seventh aspect of the present invention, at least one of the first polarizing plate and the second polarizing plate may have a thickness of 30 to 200 μm.

[0018] In an eighth aspect of the present invention, it may include a sealant disposed between the first laminate and the second laminate.

[0019] In a ninth aspect of the present invention, the variable transmittance optical laminate may further include one or more selected from the group consisting of an adhesive layer, an ultraviolet absorption layer, and an impact resistant layer.

[0020] Furthermore, the present invention relates to a method for manufacturing the variable transmittance optical laminate. Furthermore, the present invention relates to a smart window including the variable transmittance optical laminate.

[0021] Furthermore, the present invention relates to a transportation means including the smart window. Furthermore, the present invention relates to an automobile in which the smart window is applied to at least one of a front window, a rear window, a side window, a sunroof window, and an interior partition.

[0022] Furthermore, the present invention relates to a wearable device including the smart window.

[0023] Furthermore, the present invention relates to an architectural fitting including the smart window.

Advantages of the Invention

[0024] According to the variable transmittance optical laminate of the present invention, when the ratio of the compression elastic modulus of the spacer to the compression elastic modulus of either one of the first laminate and the second laminate satisfies 0.75 to 1.55 and the spacer content with respect to the total weight of the dispersed liquid crystal satisfies 0.5 to 3.0% by weight, cracks do not occur, and thus an optical laminate excellent in durability can be provided.

[0025] Also, according to the variable transmittance optical laminate of the present invention, light transmission is smooth through the liquid crystal space, the occurrence of defects is reduced, and characteristics excellent in reliability can be exhibited.

[0026] Also, according to the variable transmittance optical laminate of the present invention, a liquid crystal space is uniformly secured between the first laminate and the second laminate, and an optical laminate excellent in quality can be provided.

[0027] Also, according to the variable transmittance optical laminate of the present invention, steps such as forming a conductive layer on a substrate and bonding it to other members for forming a conventional optical laminate can be omitted, and the manufacturing process can be simplified compared to a conventional optical laminate.

Brief Description of Drawings

[0028]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0029] The present invention satisfies the condition that the ratio of the compression elastic modulus of the spacer to the compression elastic modulus of either one of the first laminate and the second laminate is in the range of 0.75 to 1.55, and the spacer content satisfies 0.5 to 3.0% by weight with respect to the total weight of the dispersed liquid crystal, so that no crack occurs in the optical laminate, a liquid crystal space is secured between the first laminate and the second laminate, light transmission is smooth, the occurrence of liquid crystal defects is reduced, and the transmittance variable optical laminate excellent in reliability, a manufacturing method thereof, and a smart window including the same are provided.

[0030] More specifically, the present invention relates to a transmittance variable optical laminate including a first laminate laminated in the order of a first polarizing plate, a first transparent conductive layer, and a first alignment film, a second laminate laminated in the order of a second polarizing plate, a second transparent conductive layer, and a second alignment film, and a dispersed liquid crystal disposed between the first laminate and the second laminate, the dispersed liquid crystal including a spacer, wherein the ratio of the compression elastic modulus of the spacer to the compression elastic modulus of either one of the first laminate and the second laminate is 0.75 to 1.55, and the spacer is contained in an amount of 0.5 to 3.0% by weight based on the total weight of the dispersed liquid crystal.

[0031] Conventionally, the presence or absence of defects in an optical laminate has been evaluated in consideration of the spacer included in the optical laminate and the individual hardness of the laminate. However, even when the presence or absence of defects is evaluated based on the hardness of the spacer and the laminate in this way, there has still been a problem that some defects occur. Therefore, the present invention provides a transmittance variable optical laminate in which no crack occurs and the occurrence rate of liquid crystal screen defects such as unevenness is significantly reduced by satisfying the condition that the ratio of the compression elastic modulus of the spacer to the compression elastic modulus of the laminate is in a predetermined range, specifically, 0.75 to 1.55, and the spacer content is in a predetermined range, specifically, 0.5 to 3.0% by weight with respect to the total weight of the dispersed liquid crystal, rather than the hardness of the spacer and the laminate in contact therewith.

[0032] In one embodiment of the present invention, the compression elastic modulus of either one of the first laminate and the second laminate may be 3,000 to 4,000 MPa, and the compression elastic modulus of the spacer may be 2,000 to 5,500 MPa. When the compression elastic moduli of the laminate and the spacer satisfy the above ranges, not only can the occurrence of cracks and liquid crystal screen defects in the optical laminate be prevented, but there may also be advantages from the viewpoint of the driving safety of the optical laminate.

[0033] The variable transmittance optical laminate of the present invention is particularly suitable for the technical field of changing the light transmittance by applying a voltage, and can be used, for example, in a smart window.

[0034] A smart window means an optical structure that controls the amount of light or heat passed by changing the light transmittance by applying an electrical signal. That is, a smart window is provided so that it can be changed to a transparent, opaque or translucent state by voltage, and is also called a variable transmittance glass, a dimming glass or a smart glass.

[0035] A smart window may be used for partitioning the interior space of vehicles and buildings or for privacy protection partitions, or may be used for daylighting windows arranged in the openings of buildings. It may also be used for highway signs, bulletin boards, scoreboards, clocks or advertising screens, and can be used to replace the glass of transportation means such as windows or sunroofs of automobiles, buses, airplanes, ships or trains.

[0036] Although the variable transmittance optical laminate of the present invention can also be applied to smart windows in the various technical fields described above, since the conductive layer is formed directly on the polarizing plate and does not include a separate substrate for forming the conductive layer, it has a thin thickness and is advantageous in bending characteristics, and can be particularly preferably used for smart windows for vehicles or buildings. In one or more embodiments, a smart window to which the variable transmittance optical laminate of the present invention is applied can be used for transportation means, for example, the front window, rear window, side window, and sunroof window of an automobile, or building fixtures, etc., and in addition to the use of blocking external light, it can also be used for partitioning the internal space of an automobile or building or protecting privacy, such as internal partitions, and can also be used for wearable devices such as helmets, glasses, or watches.

[0037] Hereinafter, embodiments of the present invention will be described more specifically with reference to the drawings. However, the following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the above-described invention content, serve to better understand 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.

[0038] The terms used in this specification are for explaining the examples and are not intended to limit the present invention. In this specification, the singular form also includes the plural form unless otherwise specifically mentioned in the text. For example, the "polarizing plate" used in this specification may mean at least one of the first polarizing plate and the second polarizing plate, the "transparent conductive layer" may mean at least one of the first transparent conductive layer and the second transparent conductive layer, the "functional coating layer" may mean at least one of the first functional coating layer and the second functional coating layer, and the "alignment film" may mean at least one of the first alignment film and the second alignment film.

[0039] As used herein, the terms "comprises" and / or "comprising" are used in a sense that does not exclude the presence or addition of one or more other components, steps, operations and / or elements other than the recited components, steps, operations and / or elements. The same reference numerals throughout the specification refer to the same components.

[0040] Spatially relative terms such as "below", "bottom surface", "lower part", "above", "upper surface", "upper part", etc. can be used to easily describe the correlation between one element or component and another element or component as shown in the drawings. Spatially relative terms should be understood as terms that include different directions of elements relative to each other during use or operation in addition to the directions shown in the drawings. For example, when covering an element shown in the drawings, an element described as "below" or "lower part" of another element may be placed "above" the other element. Therefore, the exemplary term "below" may include both the downward and upward directions. The element can also be oriented in other directions, and thus the spatially relative terms can be interpreted according to the orientation.

[0041] As used in this specification, the "plane direction" can be interpreted as a direction perpendicular to the polarizing plate and / or the transparent conductive layer, that is, the direction seen from the user's viewing side.

[0042] As used in this specification, "substantially" can be interpreted to include not only being physically completely identical or coinciding, but also being within the error range in the measurement or manufacturing process. For example, it can be interpreted as having an error range of 0.1% or less.

[0043] FIG. 1 is a diagram showing the laminated structure of a variable transmittance optical laminate according to an embodiment of the present invention, and FIG. 2 is a diagram showing the laminated structure of a polarizing plate used in the variable transmittance optical laminate. Referring to FIG. 1, the variable transmittance optical laminate 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 liquid crystal layer including a dispersed liquid crystal 300 and a spacer 400, and a first alignment film 500-1 and a second alignment film 500-2.

[0044] Referring to FIG. 2, the polarizing plate 100 may include at least one selected from the group consisting of a functional coating layer 120, a protective layer 130, or an adhesive layer 140 on both sides centered on a polarizer 110, and may further include a retardation adjusting layer (not shown), a refractive index adjusting layer (not shown), etc. As the polarizer 110, a conventional or later-developed polarizer can be used. For example, a stretched polarizer or a coated polarizer can be used.

[0045] 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 the polyvinyl acetate - based resin include polyvinyl acetate which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of the other monomers may include unsaturated carboxylic acid - based, unsaturated sulfonic acid - based, olefin - based, vinyl ether - based, acrylamide - based monomers having an ammonium group, etc. The polyvinyl alcohol (PVA) - based resin also includes modified ones, for example, polyvinyl formal or polyvinyl acetal modified with aldehydes.

[0046] In one embodiment, the coated polarizer may be formed of a liquid crystal coating composition. At this time, the liquid crystal coating composition may contain a reactive liquid crystal compound, a dichroic dye, and the like.

[0047] The reactive liquid crystal compound can mean, for example, a compound containing a mesogen skeleton and further containing one or more polymerizable functional groups. Such reactive liquid crystal compounds are variously known under the name of so-called RM (Reactive Mesogen). The reactive liquid crystal compound can form a cured film in which a polymer network is formed while being polymerized by light or heat to maintain a liquid crystal alignment.

[0048] 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 can mean a compound containing two or more polymerizable functional groups.

[0049] The dichroic dye is a component contained in the liquid crystal coating composition and imparts 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 dichroic dye may be a conventional or later-developed dichroic dye. For example, it may contain 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.

[0050] The composition for liquid crystal coating may further contain a solvent capable of dissolving the reactive liquid crystal compound and the dichroic dye. For example, propylene glycol monomethyl ether acetate (PGMEA), methyl ethyl ketone (MEK), xylene, chloroform, etc. may be used. Further, the composition for liquid crystal coating may further contain a leveling agent, a polymerization initiator, etc. within a range that does not impair the polarization characteristics of the coating film.

[0051] The functional coating layer 120 is provided to improve the hardness of the polarizing plate 100, and is not particularly limited as long as it can improve the hardness of the polarizing plate. For example, it may include a hard coating layer and / or a low refractive index layer, etc.

[0052] The hard coating layer may use a conventional or later-developed hard coating layer. According to an embodiment of the present invention, it may be formed from a composition for forming a hard coating layer containing an acrylate-based or epoxy-based compound, inorganic fine particles, a photoinitiator, etc. The acrylate-based compound may include a monomer or oligomer containing a (meth)acrylate group. The term "(meth)acryl-" used herein is used to mean "methacryl-", "acryl-", or both. Non-limiting examples of the acrylate-based 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-cyclohexanetetra(meth)acrylate, pentaglycerol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)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, iso-decyl (meth)acrylate, stearyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, phenoxyethyl (meth)acrylate, or isobornyl (meth)acrylate, etc. These may be used alone or in combination of two or more.The acrylate compound may contain an epoxy (meth)acrylate compound and / or a urethane (meth)acrylate compound. Further, the epoxy compound may contain a monomer or oligomer having at least one epoxy group in the molecule. The epoxy group may be an alicyclic epoxy group. The number of carbon atoms of the alicyclic ring contained in the epoxy group may be 3 to 7, for example, an alicyclic epoxy group (cyclohexyl epoxy) containing a cyclohexane ring may be used. The alicyclic ring may have a substituent. For example, the alicyclic ring may contain an alkyl substituent having 1 to 20 carbon atoms. When the number of carbon atoms of the alkyl substituent exceeds 20, it may be disadvantageous from the viewpoint of the curing rate. The alkyl substituent includes a linear or branched type, and in the case of a branched type, the number of carbon atoms may be 3 or more.

[0053] According to one embodiment of the present invention, the composition for forming a hard coating layer contains inorganic fine particles. According to one embodiment of the present invention, as the inorganic fine particles, inorganic fine particles having a particle size in the nanoscale, for example, nano fine particles having a particle size of 100 nm or less, or 10 to 100 nm, or 10 to 50 nm may be used. Further, as the inorganic fine particles, for example, silica fine particles, aluminum oxide particles, titanium oxide particles, zinc oxide particles, or the like may be used.

[0054] By including the inorganic fine particles, the hardness of the hard coating layer can be further improved. According to one embodiment of the present invention, the inorganic fine particles may be contained 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 containing the inorganic fine particles within the above range, the effect of improving the hardness of the hard coating film by adding the inorganic fine particles can be achieved within a range that does not deteriorate the physical properties of the hard coating composition.

[0055] According to an embodiment of the present invention, in a method for manufacturing a hard coating film, the hard coating composition contains a photoinitiator. According to an embodiment of the present invention, examples of the photoinitiator include, but are not limited to, 1-hydroxy-cyclohexyl-phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1-propanone, methyl benzoylformate, 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. Also, examples of currently commercially available 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 ones.

[0056] According to an embodiment of the present invention, the photoinitiator may be contained 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 within the above range, sufficient crosslinking photopolymerization can be achieved without degrading the physical properties of the hard coating film.

[0057] On the one hand, in the method for manufacturing the hard coating film of the present invention, in addition to the above-mentioned components, the hard coating composition may further contain additives commonly used in the technical field to which the present invention pertains, such as surfactants, anti-yellowing agents, leveling agents, or antifouling agents. Further, since its content can be variously adjusted within a range that does not deteriorate the physical properties of the composition for forming the hard coating layer according to the present invention, it is not particularly limited.

[0058] The low refractive index layer may be provided to also serve to improve the hardness of the polarizing plate within a range that does not impair the object of the present invention. The low refractive index layer may include, for example, one or more low refractive index agents selected from the group consisting of SiO2, Al2O3, MgF2, CaF, and cryolite. In some embodiments, it may include a compound or resin used in the hard coating layer. The hard coating layer and the low refractive index layer may each be used alone, or in some embodiments, may be used as a multilayer structure.

[0059] The functional coating layer 120 may be formed in direct contact with one surface of the polarizer 110 as shown in FIG. 2, but is not limited thereto. For example, when the polarizing plate includes a retardation adjusting layer or a refractive index adjusting layer, it may be formed on one surface of the retardation adjusting layer or the refractive index adjusting layer, and the functional coating layer, the retardation adjusting layer or the refractive index adjusting layer, and the polarizer may be sequentially laminated.

[0060] The functional coating layer 120 is preferably formed on the liquid crystal layer side including the dispersed liquid crystal 300 of the polarizer 110, that is, on the inner side of the polarizer 110. For example, the first protective layer 130-1, the first functional coating layer 120-1, the polarizer 110, the second protective layer 130-2, and the second functional coating layer 120-2 may be sequentially laminated. In this case, the functional coating layer can minimize cracks or scratches generated during the manufacturing or processing process of the optical laminate by imparting a level of hardness suitable for forming members such as a transparent conductive layer on the polarizing plate.

[0061] The first functional coating layer 120-1 and the second functional coating layer 120-2 may have a Vickers hardness of 18 to 41 respectively. The hardness of the first functional coating layer 120-1 and the second functional coating layer 120-2 may be the same, but it is not limited thereto, and they may have different hardnesses.

[0062] The Vickers hardness may be measured using a Vickers tip of a nanoindenter (HM500, manufactured by Helmut Fishcher). When the Vickers hardness of the functional coating layer satisfies the above range, it not only has excellent abrasion resistance but also can further improve the bending resistance or durability of the optical laminate. More specifically, it can more effectively suppress the occurrence of defects such as cracks in the conductive layer due to the pressure applied by the spacer or chemical reactions of liquid crystal, alignment film, etc. during the bonding process of the first laminate (upper laminate) and the second laminate (lower laminate).

[0063] In one or more embodiments, the thicknesses of the first functional coating layer 120-1 and the second functional coating layer 120-2 may each be 1 to 30 μm, more preferably 1 to 20 μm. The thickness may mean the thickness after drying. When the thicknesses of the first functional coating layer 120-1 and the second functional coating layer 120-2 satisfy the above range, they have excellent hardness, can be made thinner, and can further improve the bending resistance or durability.

[0064] The protective layer 130 is for preserving the polarization characteristics of the polarizer from post-processes and the external environment, and can be embodied in the form of a protective film or the like.

[0065] The protective layer may be formed in direct contact with one or both surfaces of the polarizer, but is not limited thereto. For example, the protective layer may be used as a multilayer structure in which one or more protective layers are continuously laminated, or may be formed in direct contact with other members such as a retardation adjustment layer.

[0066] In one or more embodiments, the protective layer 130 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).

[0067] In addition, the protective layer 130 may further contain an ultraviolet absorber on its outermost surface to prevent a decrease in the function of the optical laminate. The ultraviolet absorber is not particularly limited as long as it can prevent the deterioration of the optical laminate by ultraviolet rays. For example, salicylic acid-based ultraviolet absorbers (such as phenyl salicylate, p-tert-butyl salicylate), benzophenone-based ultraviolet absorbers (such as 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone), 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, a mixture of octyl-3-[3-tert-butyl-4-hydroxy-5-(chloro-2H-benzotriazol-2-yl)phenyl]propionate and 2-ethylhexyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazol-2-yl)phenyl]propionate, etc.), cyanoacrylate-based ultraviolet absorbers (such as 2'-ethylhexyl-2-cyano-3,3-diphenylacrylate, ethyl-2-cyano-3-(3',4'-Methylenedioxyphenyl)-acrylate, etc.), triazine-based ultraviolet absorbers, etc. may be used. Benzotriazole-based ultraviolet absorbers and triazine-based ultraviolet absorbers with high transparency and excellent effects of preventing deterioration of polarizing plates and variable transmittance layers are preferred, and benzotriazole-based ultraviolet absorbers with more appropriate spectral absorption spectra are particularly preferred. The benzotriazole-based ultraviolet absorber may be bis-ified. For example, 6,6'-methylenebis(2-(2H-benzo[d][1,2,3]triazol-2-yl)-4-(2,4,4-trimethylpentan-2-yl)phenol), 6,6'-methylenebis(2-(2H-benzo[d][1,2,3]triazol-2-yl)-4-(2-hydroxyethyl)phenol), etc. may also be used.,

[0068] The polarizing plate 100 may further include an adhesive layer 140 to ensure uniform adhesive force between the base materials. The adhesive layer can be formed using an adhesive or a pressure-sensitive adhesive, and as the adhesive, it is preferable to use a photocurable adhesive.

[0069] The photocurable adhesive is irradiated with active energy rays such as ultraviolet rays (UV) and electron beams (EB), crosslinked and cured to exhibit strong adhesive force, and may be composed of a reactive oligomer, a reactive monomer, a photopolymerization initiator, etc.

[0070] The reactive oligomer is an important component that determines the properties of the adhesive, and forms a polymer bond by a photopolymerization reaction to form a cured film. Reactive oligomers that can be used include polyester-based resins, polyether-based resins, polyurethane-based resins, epoxy-based resins, polyacrylic-based resins, silicone-based resins, etc.

[0071] The reactive monomer serves as a crosslinking agent and a diluent for the aforementioned reactive oligomer, and affects the adhesion properties. Reactive monomers that can be used include monofunctional monomers, polyfunctional monomers, epoxy-based monomers, vinyl ethers, cyclic ethers, and the like.

[0072] The photopolymerization initiator serves to absorb light energy to generate radicals or cations and initiate photopolymerization, and an appropriate one may be selected and used according to the photopolymerizable resin.

[0073] The pressure-sensitive adhesive is not particularly limited as long as it has adhesiveness and viscoelasticity. From the viewpoint of easy availability, etc., it may preferably be an acrylic pressure-sensitive adhesive, for example, one containing a (meth)acrylate copolymer, a crosslinking agent, a solvent, and the like. The crosslinking agent may use a conventional or later-developed crosslinking agent, for example, one containing a polyisocyanate compound, an epoxy resin, a melamine resin, a urea resin, dialdehydes, a methylol polymer, and the like, and preferably one containing a polyisocyanate compound. The solvent may contain a normal solvent used in the field of resin compositions, for example, alcohol-based compounds such as methanol, ethanol, isopropanol, butanol, propylene glycol monomethyl ether; ketone-based compounds such as methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone; acetate-based compounds such as methyl acetate, ethyl acetate, butyl acetate, propylene glycol monomethyl acetate; cellosolve-based compounds such as methyl cellosolve, ethyl cellosolve, propyl cellosolve; hydrocarbon-based compounds such as hexane, heptane, benzene, toluene, xylene, and the like. These may be used alone or in combination of two or more.

[0074] In one embodiment, the adhesive layer can be formed on one or both surfaces of the polarizer by a lamination method, and the thickness of the adhesive layer in the polarizing plate may be 0.01 to 50 μm, preferably 0.05 to 20 μm, more preferably 0.1 to 10 μm in order to ensure sufficient adhesive force and minimize the thickness of the optical laminate.

[0075] The transparent conductive layer 200 is provided for driving the liquid crystal layer and may be formed in direct contact with the polarizing plate 100. For example, as shown in FIG. 1, the first transparent conductive layer 200-1 and the second transparent conductive layer 200-2 may be formed in direct contact with the first polarizing plate 100-1 and the second polarizing plate 100-2, respectively. The optical laminate used in the manufacture of conventional smart windows and the like is manufactured by forming a conductive layer for liquid crystal driving on one surface of a substrate and bonding the other surface of the substrate to a polarizing plate. However, the transmissivity variable optical laminate according to the present invention directly forms a conductive layer on one surface of a polarizing plate without including a separate substrate for forming the conductive layer, thereby reducing the thickness of the laminate and improving the transmissivity and bending characteristics in the light transmission mode. In one embodiment, the transparent conductive layer 200 may be formed by directly depositing on one surface of the polarizing plate 100. At this time, the transparent conductive layer 200 may be formed in direct contact with the surface of the polarizing plate 100 that has been pretreated, such as corona treatment or plasma treatment, on one surface of the polarizing plate 100 in order to improve the adhesion to the polarizing plate 100. The pretreatment is not limited to corona treatment or plasma treatment, and pretreatment processes that are conventional or developed in the future may be used within the scope that does not impair the object of the present invention. In another embodiment, the transparent conductive layer 200 may be formed in direct contact with the polarizing plate 100 with an easy adhesion layer (not shown) provided on one surface of the polarizing plate 100 interposed therebetween in order to improve the adhesion to the polarizing plate 100. The transparent conductive layer 200 preferably has a transmissivity of 50% or more with respect to visible light. For example, it may include one or more selected from the group consisting of transparent conductive oxides, metals, carbon-based substances, conductive polymers, conductive inks, and nanowires, but is not limited thereto, and materials of conventional or future-developed transparent conductive layers may be used. Further, the conductive layer may be configured in a two-layer or more structure by combining the substances. For example, the conductive layer may include a two-layer structure of a metal layer and a transparent conductive oxide layer, thereby reducing the reflectivity of incident light and increasing the transmissivity.Since the metal layer has a high reflectivity, using it alone may reduce the visibility of the screen. However, by laminating a transparent conductive oxide layer, the reflectivity can be lowered and the transmittance can be improved.

[0076] More specifically, 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), and zinc oxide (ZnO). Also, 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), palladium (Pd), neodymium (Nd), and alloys containing at least one of these, 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, PEDOT, and polyaniline. The conductive ink may be an ink in which metal powder and a curable polymer binder are mixed, and the nanowire may be, for example, a silver nanowire (AgNW).

[0077] In addition, the transparent conductive layer 200 may be formed in a structure of two or more layers by combining the substances. For example, it may be formed in a two-layer structure including a metal layer and a transparent conductive oxide layer so as to reduce the reflectance of incident light and increase the transmittance. The transparent conductive layer 200 may be formed by a method commonly used in the art. For example, coating processes such as spin coating, roller coating, bar coating, dip coating, gravure coating, curtain coating, die coating, spray coating, doctor coating, kneader coating, etc.; printing processes such as screen printing, spray printing, inkjet printing, letterpress printing, gravure printing, lithographic printing, etc.; deposition processes such as IML (In-Mold Labeling) injection method and CVD (chemical vapor deposition), PVD (physical vapor deposition), PECVD (plasma enhanced chemical vapor deposition), etc., and dry or wet plating processes. Among these methods, an appropriate process may be selected for formation.

[0078] The dispersed liquid crystal 300 is included in the liquid crystal layer that changes the driving mode of the optical laminate by adjusting the transmittance of light incident from one or more directions by an electric field, and includes a spacer 400. For example, the dispersed liquid crystal 300 can be located in a liquid crystal space provided by a sealant (not shown) and a spacer 400 provided between the first laminate and the second laminate. The dispersed liquid crystal 300 is driven by an electric field in the same sense as a liquid crystal, and is not particularly limited as long as the transmittance of light can be controlled. Conventional or later-developed dispersed liquid crystals can be used. For example, the content regarding the reactive liquid crystal compound of the aforementioned coating type polarizer can be similarly applied. The liquid crystal behavior mode of the liquid crystal layer is not particularly limited. For example, it may be driven in a TN (Twisted nematic) mode, but in addition, it may also be driven in an STN (Super twisted nematic) mode, a VA (Vertical alignment) mode, etc.

[0079] The sealant (not shown) can be positioned between the first and second laminates in the non-active region. The sealant can serve to bond the first and second laminates and, together with the spacer, can secure a space for providing a liquid crystal layer between the first and second laminates. The sealant is not particularly limited as long as it bonds each laminate to secure the liquid crystal layer space, and a conventional or later-developed sealant can be used. For example, it may contain a curable resin as the base resin. As the base resin, an ultraviolet curable resin or a thermosetting resin known to be used for sealants in the art may be used. The ultraviolet curable resin may be a polymer of an ultraviolet curable monomer. The thermosetting resin may be a polymer of a thermosetting monomer. As the base resin of the sealant, for example, an acrylate resin, an epoxy resin, a urethane resin, a phenolic resin, or a mixture of these resins may be used. In one embodiment, the base resin may be an acrylate resin, and the acrylate resin may be a polymer of an acrylic monomer. The acrylic monomer may be, for example, a polyfunctional acrylate. In another embodiment, the sealant may further contain a monomer component in the base resin. The monomer component may be, for example, a monofunctional acrylate. In this specification, a monofunctional acrylate can mean a compound having one acrylic group, and a polyfunctional acrylate can mean a compound having two or more acrylic groups. The curable resin can be cured by irradiation with ultraviolet light and / or heating. The ultraviolet irradiation conditions or heating conditions may be appropriately carried out within a range that does not impair the object of the present application. The sealant may further contain an initiator, for example, a photoinitiator or a thermal initiator, if necessary. The sealant may be formed by a method commonly used in the art. For example, it may be formed by drawing the sealant onto the outer periphery (i.e., the non-active region) of the liquid crystal layer using a dispenser equipped with a nozzle.

[0080] The spacer 400 serves to maintain a constant liquid crystal cell gap in the liquid crystal layer, and can include at least one or more spacers among ball spacers and column spacers. In particular, from the perspective of processability, it is preferably a ball spacer. The spacer 400 is included in the dispersed liquid crystal, and may be one or more. There is no particular limitation on the height as long as it is suitable for supporting the liquid crystal layer.

[0081] In one embodiment, the spacer 400 may be included in an amount of 0.5 to 3.0% by weight based on the total weight of the dispersed liquid crystal. When the content of the spacer satisfies the above range, there are not only advantages from the viewpoints of the user's visibility and improvement of the transmittance in the transmissive mode, but also advantages from the viewpoint that it is possible to significantly reduce liquid crystal screen defects such as cracks or unevenness in the optical laminate.

[0082] The alignment film 500 is not particularly limited as long as it can add alignment properties to the dispersed liquid crystal, and preferably may include a photo-alignable or photocurable polymer, etc. For example, the alignment film 500 can be produced by applying and curing an alignment film coating composition containing a photo-alignable or photocurable polymer, a photoinitiator, and a solvent.

[0083] The photo-alignable or photocurable polymer is not particularly limited, and a thinner mate-based polymer, a polyimide-based polymer, etc. may be used. For example, poly(vinyl cinnamate) (PVCi), poly(siloxane cinnamate) (PSCN), poly(ω(4-chalconyloxy)alkoxyphenylmaleimide, 6-FDA-HAB-Cl, etc. may be used, or a polymer capable of exhibiting alignment properties developed conventionally or in the future may be used.

[0084] The alignment film 500 may include a recess formed by the spacer 400.

[0085] In one embodiment, the polarizing plate 100 may further include other configurations for assisting or enhancing the characteristics of the optical laminate in addition to the above-described components. For example, it may further include a retardation adjustment layer, a refractive index adjustment layer, etc. to further improve the optical characteristics.

[0086] The retardation adjustment layer is for complementing the optical characteristics of the optical laminate, and may be embodied in the form of a retardation film or the like, and a conventional or later-developed retardation film or the like may 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 may be used, and these may be used alone or in combination.

[0087] The retardation adjustment layer may be formed in direct contact with one surface of the polarizer, but is not limited thereto. For example, the retardation adjustment layer may be formed in direct contact with one surface of the protective layer, or may be formed in direct contact with one surface of the refractive index adjustment layer.

[0088] The retardation adjustment layer may use a polymer stretched film or a liquid crystal polymerization film obtained by stretching a polymer film capable of imparting optical anisotropy by stretching in an appropriate manner.

[0089] In one embodiment, the polymer stretched film may use a polymer layer including 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 polymers such as polyvinyl alcohol (PVA) or triacetyl cellulose (TAC), or copolymers of two or more monomers among the monomers forming the polymer.

[0090] The method for obtaining the polymer stretched film is not particularly limited. For example, it can be obtained by stretching the polymer material after forming it into a film shape. The method for forming it 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, and cast molding, and secondary processing molding methods such as pressure air molding and vacuum molding may also be used. Among them, extrusion molding and cast molding are preferably used. At this time, for example, an unstretched film can be extrusion molded using an extruder equipped with a T-die, a circular die, etc. When obtaining a molded product by extrusion molding, a material obtained by previously melt-kneading various resin components, additives, etc. can be used, or it can also be molded through melt-kneading during extrusion molding. Further, after dissolving various resin components using a solvent common to various resin components, such as a solvent such as chloroform or methylene dichloride, an unstretched film may be cast molded by cast drying and solidifying.

[0091] The polymer stretched film may be uniaxially stretched in the machine flow direction (MD; Mechanical Direction, longitudinal direction or length direction) of the formed film, or uniaxially stretched in the direction transverse to the machine flow direction (TD; Transverse Direction, transverse direction or width direction). Also, a biaxially stretched film may be manufactured by stretching by sequential biaxial stretching methods such as roll stretching and tenter stretching, simultaneous biaxial stretching methods by tenter stretching, biaxial stretching methods by tubular stretching, etc.

[0092] The liquid crystal polymer film can contain the reactive liquid crystal compound in a polymerized state. The above-described content regarding the reactive liquid crystal compound of the coating type polarizer can be similarly applied to the reactive liquid crystal compound.

[0093] In one or more embodiments, the thickness of the retardation adjusting layer may be 10 to 100 μm in the case of a polymer stretched film, or 0.1 to 5 μm in the case of a liquid crystal polymer film.

[0094] The refractive index adjustment layer (not shown) is provided to compensate for the refractive index difference of the optical laminate due to the transparent conductive layer 200, and may serve to improve visual recognition characteristics and the like by reducing the refractive index difference. Further, the refractive index adjustment layer may be provided to correct the hue caused by the transparent conductive layer 200. On the other hand, when the transparent conductive layer has a pattern, the transmittance difference between the pattern region where the pattern is formed and the non-pattern region where the pattern is not formed can be compensated through the refractive index adjustment layer.

[0095] Specifically, the transparent conductive layer 200 is laminated adjacent to another member (for example, a polarizer) having a different refractive index from it, and a difference in light transmittance may be induced by the refractive index difference with the adjacent other layer. In particular, when a pattern is formed on the transparent conductive layer, a problem may occur in that it can be visually recognized so as to distinguish the pattern region and the non-pattern region. Therefore, by including the refractive index adjustment layer, the refractive index is compensated so that the difference in light transmittance of the optical laminate can be reduced, and in particular, when a pattern is formed on the transparent conductive layer, the pattern region and the non-pattern region are not distinguished and visually recognized.

[0096] In one embodiment, the refractive index of the refractive index adjustment layer may be appropriately selected depending on the material of another adjacent member, but is preferably 1.4 to 2.6, and more preferably may be 1.4 to 2.4. In this case, light loss due to a sharp refractive index difference between the other member and the transparent conductive layer 200 can be prevented.

[0097] The refractive index adjustment layer is not particularly limited as long as it can prevent a sharp refractive index difference between the transparent conductive layer 200 and another member such as a polarizer, and a compound used for forming a conventional or later-developed refractive index adjustment layer may be used. For example, it may be formed from a refractive index adjustment layer forming composition containing a polymerizable isocyanurate compound.

[0098] In one embodiment, the polarizing plate 100 may further include other configurations for assisting or enhancing the characteristics of the polarizer in addition to the above-described components. For example, in order to further improve mechanical durability, it may further include an overcoat layer or the like.

[0099] In one or more embodiments, the polarizing plate 100 may have a thickness of 30 to 200 μm, preferably 30 to 170 μm, and more preferably 50 to 150 μm. In this case, the polarizing plate 100 can be used to manufacture an optical laminate with a thin thickness while maintaining optical characteristics.

[0100] The transmissivity variable optical laminate of the present invention may further include other members as long as the object of the present invention is not impaired. For example, it may further include an adhesive layer 600 (see FIGS. 3 to 5), or may further include an ultraviolet absorption layer and an impact resistant layer.

[0101] The adhesive layer 600 can be formed using an adhesive or a pressure-sensitive adhesive. It preferably has an appropriate adhesive force so that peeling, bubbles, etc. do not occur during handling of the optical laminate, and also has transparency and thermal stability, and can have point elastic characteristics applicable to a smart window.

[0102] Since the content regarding the adhesive for the adhesive layer 140 can be directly applied to the adhesive and the pressure-sensitive adhesive, the description thereof is omitted.

[0103] The thickness of the adhesive layer 600 may be appropriately determined according to the type of resin serving as the adhesive, the adhesive strength, the environment in which the adhesive is used, etc. In one embodiment, in order to ensure sufficient adhesive force and minimize the thickness of the optical laminate, in the case of the adhesive layer, it may be 0.1 to 500 μm, preferably 0.5 to 450 μm, more preferably 1 to 400 μm. In the case of the pressure-sensitive adhesive layer, it may be 2 to 30 μm, preferably 3 to 20 μm, more preferably 5 to 10 μm. In one embodiment, the adhesive layer 600 may be formed on one or both surfaces of the polarizing plate by a lamination or vacuum bonding method.

[0104] The ultraviolet absorption layer is not particularly limited as long as it can prevent the deterioration of the optical laminate by ultraviolet rays, and the content regarding the ultraviolet absorber described in the protective layer 130 of the polarizing plate 100 can be directly applied, so the description is omitted.

[0105] The impact-resistant layer is located in the inner direction and is not particularly limited as long as it can function to relieve the impact and prevent the breakage of the inner substrate when an impact is applied to the front surface of the window. Preferably, a material with a large tolerance for deformation energy, for example, a thermoplastic resin with high toughness, is preferred. Examples of such resins include polycarbonate-based resins, polyimide-based resins, polyamide-based resins, polyamideimide-based resins, polyester resins, etc. Furthermore, since the present invention is intended to be used in a display device, it is preferable to use a resin with excellent light transmittance, preferably an optically transparent resin.

[0106] FIG. 3 is a diagram showing the laminated structure of a vehicle smart window to which a transmittance variable optical laminate according to an embodiment of the present invention is applied, FIG. 4 is a diagram showing the laminated structure of an architectural fixture smart window to which a transmittance variable optical laminate according to an embodiment of the present invention is applied, and FIG. 5 is a diagram showing the laminated structure of an architectural fixture smart window according to another embodiment of the present invention.

[0107] Referring to FIGS. 3 to 5, the present invention includes, in addition to the transmittance-variable optical laminate, a smart window including the same, and an automobile in which the smart window is applied to at least one of a front window, a rear window, a side window, a sunroof window, and an interior partition, and a building fixture including the smart window. For example, an automobile including the smart window of the present invention may be one in which vehicle glass 700 is joined to both surfaces of a transmittance-variable optical laminate including a polarizing plate 100, a transparent conductive layer 200, a liquid crystal layer, and an adhesive layer 600 (see FIG. 3). For example, after placing an adhesive film and vehicle glass on both surfaces of the transmittance-variable optical laminate, it may be manufactured by heating at a temperature of 90° C. and a vacuum state of about 1 bar for 10 to 20 minutes using a press machine. The adhesive film may include an EVA film, a PVB film, or the like. Further, it may be one in which a building fixture (glass for fixtures) 800 is joined to both surfaces (see FIG. 4) or one surface (see FIG. 5) of the transmittance-variable optical laminate. After applying a UV adhesive to join the glass for fixtures to both surfaces of the transmittance-variable optical laminate and then UV curing, a smart window product for fixtures having the same configuration as in FIG. 4 or FIG. 5 may be manufactured. It may also be one in which a smart window product for fixtures having the same configuration as in FIG. 4 or FIG. 5 is manufactured by joining the glass for fixtures to one surface of the transmittance-variable optical laminate by a laminating method.

[0108] In addition, the smart window may be applied to transportation means and wearable devices generally used in the art.

Example

[0109] Hereinafter, embodiments of the present invention will be specifically described. However, the present invention is not limited to the embodiments disclosed below and can be embodied in various different forms. Merely, these embodiments are provided to complete the disclosure of the present invention and fully inform those with ordinary knowledge in the technical field to which the present invention pertains of the scope of the invention. The present invention is only defined by the scope of the claims. “%” and “parts” are mass % and parts by mass, respectively, unless otherwise specified.

[0110] Production Example 1: Production of a Polarizing Plate (1) Swelling Treatment Step A polyvinyl alcohol film with a thickness of 60 μm (raw film) (manufactured by Kuraray Co., Ltd., trade name “Kuraray POVAL Film VF-PE#6000”, average degree of polymerization 2400, degree of saponification 99.9 mol%) was continuously drawn out from the raw film roll and conveyed, and immersed in a swelling bath filled with pure water at 20°C for 30 seconds. In this swelling treatment step, a difference in peripheral speed was created between the nip rolls to perform stretching between the rolls (uniaxial stretching in the longitudinal direction). The stretching ratio based on the raw film was set to 2.5 times.

[0111] (2) Dyeing Treatment Step Next, the film that passed through the nip rolls was immersed in a dyeing bath at 30°C with a mass ratio of pure water / potassium iodide / iodine / boric acid of 100 / 2 / 0.01 / 0.3 for 120 seconds. Also in this dyeing treatment, a difference in peripheral speed was created between the nip rolls to perform stretching between the rolls (uniaxial stretching in the longitudinal direction). The stretching ratio based on the film after the swelling treatment step was set to 1.1 times.

[0112] (3) Crosslinking Treatment Step Next, the film that passed through the nip rolls was immersed in a first crosslinking bath at 56°C with a mass ratio of pure water / potassium iodide / boric acid of 100 / 12 / 4 for 70 seconds. A difference in peripheral speed was created between the nip rolls and the nip rolls provided between the first crosslinking bath and the second crosslinking bath to perform stretching between the rolls (uniaxial stretching in the longitudinal direction). The stretching ratio based on the film after the dyeing treatment step was set to 1.9 times.

[0113] (4) Complementary color treatment step Next, the film after the crosslinking treatment was immersed in a second crosslinking bath at 40 °C with a potassium iodide / boric acid / pure water (mass ratio) of 9 / 2.9 / 100 for 10 seconds.

[0114] (5) Cleaning treatment step Next, the film after the second crosslinking treatment was immersed in a cleaning bath containing pure water at 14 °C for 5 seconds and cleaned at a shower rate of 5 m 3 / h and a shower temperature of 14 °C.

[0115] (6) Drying treatment step Next, the film after the cleaning treatment step was passed through a drying furnace 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 obtained polarizer film was about 21 μm.

[0116] (7) Bonding treatment step Next, an aqueous adhesive containing 5 parts by mass of polyvinyl alcohol with respect to 100 parts by mass of water was prepared as an adhesive. Thereafter, protective films were laminated on both sides of the polarizer film using the prepared UV adhesive. The obtained laminate was subjected to UV exposure to cure the adhesive, and an upper polarizing plate and a lower polarizing plate were produced, respectively. The thickness of the adhesive layer in the obtained polarizing plate was about 2 μm.

[0117] Production Example 2: Production of a composition for forming a hard coating layer 16.2 g of a dendrimer compound (manufactured by Miwa Specialty Chemicals Co., Ltd., SP-1106), 14.4 g of inorganic nanoparticles (10 to 20 nm, silica particles: 50% by weight, 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-hydroxycyclohexyl phenyl ketone), and 2.9 g of methyl ethyl ketone were mixed to produce a composition for forming a hard coating layer.

[0118] Production Example 3: Production of a hard coating layer The composition for forming a hard coating layer produced in Production Example 2 was adjusted in terms of the Mayer Bar type and solid content on one surface of each of the upper polarizing plate and the lower polarizing plate produced in Production Example 1, and after curing, the hard coating thickness was calculated and bar-coated, dried at 80 °C for 5 minutes, and then cured with a light amount of 500 mJ / m 2 to form upper and lower polarizing plates each having a hard coating layer formed on one surface. After drying the hard coating layer, the Vickers hardness was 40 and the thickness was about 8 to 12 μm.

[0119] Production Example 4: Fabrication of a transparent conductive layer The upper and lower polarizing plates produced in Production Example 3 were placed, 450 W of DC power was applied to operate the sputtering gun, and then plasma was induced on an ITO (10 wt% Sn doped In2O3) target to form a transparent conductive film (90 nm). The formed transparent conductive film was ion-treated by operating an ion gun with 50 W of DC power. At this time, the pressure was maintained at 3 mTorr at room temperature, and it was produced while supplying argon gas and oxygen gas at 30 sccm and 1 sccm, respectively. At this time, the ITO thickness was measured by FT-SEM, and the ITO sheet resistance (Ω / □) was measured using a four-point probe.

[0120] Production Example 5: Fabrication of an alignment film An alignment liquid was coated and dried (80 °C / 2 minutes) on the ITO surfaces of the upper and lower polarizing plates produced in Production Example 4. Then, UV was irradiated onto the dried alignment liquid to form an alignment film, thereby fabricating an upper polarizing plate laminate (i.e., the first laminate) and a lower polarizing plate laminate (i.e., the second laminate), respectively.

[0121] Production Example 6: Fabrication of an optical laminate b-1 After forming a PEDOT electrode layer (manufactured by DAEHAMANTECH Co., Ltd.) on the hard coating layers of the upper polarizing plate and the lower polarizing plate, except for forming ITO on the PEDOT electrode layer, according to the above Production Examples 1 to 5, an upper polarizing plate laminate in which an upper polarizing plate / hard coating layer / PEDOT / ITO / orientation film are sequentially laminated, and a lower polarizing plate laminate in which a lower polarizing plate / hard coating layer / PEDOT / ITO / orientation film are sequentially laminated were each manufactured. Then, based on 100 ml of IPA, spacers were mixed to produce a mixed solvent. The produced mixed solvent was put into a spacer dispenser (SDSS-KHU02, SHINDO ENG LAB), sprayed onto the lower polarizing plate laminate under the condition of 110 °C, and then dried for 20 minutes to form spacers on the orientation film of the lower polarizing plate laminate. Then, a sealant (UVF-006, 70,000 mPa·s, manufactured by SEKISUI Co., Ltd.) was applied according to the product size using a sealant dispenser (SHOTmini 200Ωx, manufactured by MUSASHI Co., Ltd.) on the outer peripheral surface of the lower polarizing plate laminate. Then, in a state where the polarization axes of the upper polarizing plate and the lower polarizing plate are arranged parallel to each other at 0° or 90°, a dispersed liquid crystal was injected onto the orientation film of the upper polarizing plate laminate by the ODF (One Drop Filling) process method. Then, the upper polarizing plate laminate and the lower polarizing plate laminate were bonded at a pressure of 3 Kg / cm 2 and then UV curing (500 mJ / cm 2 ) was performed along the sealant line to manufacture an optical laminate b-1 for a smart window.

[0122] Production Example 7: Fabrication of optical laminate b-2 By the above Production Examples 1 to 5, an upper polarizing plate laminate in which an upper polarizing plate / hard coating layer / ITO / orientation film were sequentially laminated, and a lower polarizing plate laminate in which a lower polarizing plate / hard coating layer / ITO / orientation film were sequentially laminated were each manufactured. Based on 100 ml of IPA, spacers were mixed to produce a mixed solvent. Then, the produced mixed solvent was put into a spacer dispenser (SDSS-KHU02, SHINDO ENG LAB), sprayed onto the lower polarizing plate laminate under the condition of 110°C, and then dried for 20 minutes to form spacers on the orientation film of the lower polarizing plate laminate. After that, a sealant (UVF-006, 70,000 mPa·s, manufactured by SEKISUI) was applied to the outer peripheral surface of the lower polarizing plate laminate according to the product size using a sealant dispenser (SHOTmini 200Ωx, manufactured by MUSASHI). Then, in a state where the polarizing axes of the upper polarizing plate and the lower polarizing plate were arranged parallel to each other at 0° or 90°, a dispersed liquid crystal was injected onto the orientation film of the upper polarizing plate laminate by the ODF (One Drop Filling) process method. Then, the upper polarizing plate laminate and the lower polarizing plate laminate were joined under a pressure of 3 Kg / cm 2 . After that, UV curing (500 mJ / cm 2 ) was performed along the sealant line to manufacture an optical laminate b-2 for a smart window.

[0123] Production Example 8: Fabrication of Optical Laminate b-3 According to the above Manufacturing Examples 1, 4, and 5, an upper polarizer laminate in which an upper polarizer / ITO / orientation film were sequentially laminated, and a lower polarizer laminate in which a lower polarizer / ITO / orientation film were sequentially laminated were each manufactured. First, based on 100 ml of IPA, spacers were mixed to produce a mixed solvent. Then, the produced mixed solvent was put into a spacer dispenser (SDSS-KHU02, SHINDO ENG LAB), sprayed onto the lower polarizer laminate under the condition of 110 °C, and dried for 20 minutes to form spacers on the orientation film of the lower polarizer laminate. After that, a sealant (UVF-006, 70,000 mPa·s, manufactured by SEKISUI) was applied to the outer peripheral surface of the lower polarizer laminate according to the product size using a sealant dispenser (SHOTmini 200Ωx, manufactured by MUSASHI). Then, while the polarization axes of the upper polarizer and the lower polarizer were arranged parallel to each other at 0° or 90°, a dispersed liquid crystal was injected onto the orientation film of the upper polarizer laminate by the ODF (One Drop Filling) process method. Then, the upper polarizer laminate and the lower polarizer laminate were joined under a pressure of 3 Kg / cm 2 After that, UV curing (500 mJ / cm 2 ) was performed along the sealant line to manufacture an optical laminate b-3 for a smart window.

[0124] Examples and Comparative Examples Optical laminates of Examples 1 to 8 and Comparative Examples 1 to 5 were respectively fabricated according to the spacer types, contents, and optical laminate types shown in Tables 1 and 2 below.

[0125]

Table 1

[0126]

Table 2

[0127] -a-1: EZ3P-020 (manufactured by SEKISUI) -a-2: SP-205 (manufactured by SEKISUI) -a-3: EX-005 (manufactured by Sekisui) -a-4: EXH-005 (manufactured by Sekisui) -a-5: KBN-505 (manufactured by Sekisui) -a-6: SI (manufactured by Sekisui) -b-1: Optical laminate according to Production Example 6 -b-2: Optical laminate according to Production Example 7 -b-3: Optical laminate according to Production Example 8 Experimental Example (1) Compressive elastic modulus ratio The compressive elastic moduli of spacers a-1 to a-6 were determined by the plastic compression test method JIS K7208 and are the values calculated at 10% K value of 3 μm particles using a nanoindenter.

[0128] Also, the compressive elastic moduli of the upper and lower polarizer laminates were measured using the Vickers tip of a nanoindenter (HM500, manufactured by Helmut Fishcher). At this time, the hardness of the substrate was 100 mN of the maximum load, the load speed was from 0 mN to 100 mN in 12 seconds, maintained for 5 seconds, and then the unload speed was from 100 mN to 0 mN in 12 seconds.

[0129] Thereafter, the ratio of the compressive elastic modulus of the spacer to that of the upper (and / or lower) polarizer laminate was calculated, and the results are shown in Tables 1 and 2 above.

[0130] (2) Evaluation of crack The presence or absence of crack generation on the surface of the optical laminate was confirmed using an optical microscope (MX61, manufactured by OLYMPUS) with a 10 mm mandrel on a cylinder mandrel bending tester COAD.711. Specifically, the cross-section of the substrate in contact with the spacer was confirmed by magnifying 10 times with an optical microscope. Based on the following evaluation criteria, the results are shown in Tables 1 and 2 above.

[0131] <Evaluation Criteria> ○: No crack occurs ×: Crack occurs (3) Evaluation of substrate contact Similar to the crack evaluation, using a 10-mm mandrel on a cylinder mandrel bending tester COAD.711, the presence or absence of contact between the upper polarizing plate laminate and the lower polarizing plate laminate at the bent portion was confirmed using an optical microscope (MX61 manufactured by OLYMPUS). Based on the following evaluation criteria, the results were shown in Tables 1 and 2 above.

[0132] <Evaluation Criteria> ○: Light transmission was confirmed. ×: Black unevenness was visually observed. Referring to Table 1 above, in the case of the optical laminates of Examples 1 to 8 where the ratio of the compression elastic modulus of the spacer to the compression elastic modulus of the upper and lower polarizing plate laminates is 0.75 to 1.55 and the content of the spacer relative to the total weight of the dispersed liquid crystal is 0.5 to 3.0% by weight, as a result of the bending evaluation, not only no crack occurs in the base material of the optical laminate, particularly the base material in contact with the spacer, but also the upper polarizing plate laminate and the lower polarizing plate laminate at the bent portion do not come into contact, indicating good light transmittance.

[0133] On the other hand, referring to Table 2 above, in the case of the optical laminates of Comparative Examples 1 to 3 where, even though the content of the spacer relative to the total weight of the dispersed liquid crystal satisfies 0.5 to 3.0% by weight, the ratio of the compression elastic modulus of the spacer to the compression elastic modulus of the upper and lower polarizing plate laminates does not satisfy 0.75 to 1.55, as a result of the bending evaluation, it can be seen that cracks (in Comparative Examples 2 and 3) occur in the base material of the optical laminate, particularly the base material in contact with the spacer, or black unevenness is visually observed in the area where the upper polarizing plate laminate and the lower polarizing plate laminate at the bent portion come into contact (Comparative Example 1).

[0134] Also, referring to Table 2, in the case of the optical laminates of Comparative Examples 4 and 5 where the ratio of the compression elastic modulus of the spacer to the compression elastic modulus of the upper and lower polarizer laminates satisfies 0.75 to 1.55, but the content of the spacer with respect to the total weight of the dispersed liquid crystal does not satisfy 0.5 to 3.0% by weight, as a result of the bending evaluation, cracks occur in the base material of the optical laminate, particularly in the base material in contact with the spacer (Comparative Example 5), and it can be seen that the upper polarizer laminate and the lower polarizer laminate in the bent portion come into contact with each other and black unevenness is visually recognized in the area (Comparative Example 4).

[0135] Therefore, in the case of the optical laminate of the present invention where the ratio of the compression elastic modulus of the spacer to the compression elastic modulus of the upper and / or lower polarizer laminates satisfies 0.75 to 1.55 and the content of the spacer with respect to the total weight of the dispersed liquid crystal satisfies 0.5 to 3.0% by weight, it can be seen that not only is the bending property excellent, but also it is easy to secure the liquid crystal space and the light transmittance is excellent.

Industrial Applicability

[0136] According to the variable transmittance optical laminate of the present invention, when the ratio of the compression elastic modulus of the spacer to the compression elastic modulus of either one of the first laminate and the second laminate satisfies 0.75 to 1.55 and the spacer content with respect to the total weight of the dispersed liquid crystal satisfies 0.5 to 3.0% by weight, cracks do not occur, and thus an optical laminate excellent in durability can be provided.

Explanation of Reference Numerals

[0137] 100: Polarizer 110: Polarizer 120: Functional Coating Layer 130: Protective Layer 140: Adhesive Layer 200: Transparent Conductive Layer 300: Dispersed Liquid Crystal 400: Spacer 500: Alignment Film 600: Adhesive Layer 700: Glass for Vehicle Smart Window Glass for Smart Windows for Architectural Fixtures

Claims

1. A first laminate in which a first polarizing plate, a first transparent conductive layer, and a first alignment film are laminated in this order; A second laminate in which a second polarizing plate, a second transparent conductive layer, and a second alignment film are laminated in this order; A dispersed liquid crystal disposed between the first laminate and the second laminate, and the dispersed liquid crystal contains spacers, The ratio of the compression elastic modulus of the spacer to the compression elastic modulus of any one of the first laminate and the second laminate is 0.75 to 1.55, The spacer is contained in an amount of 0.5 to 3.0% by weight based on the total weight of the dispersed liquid crystal. A transmissivity variable optical laminate.

2. The compression elastic modulus of any one of the first laminate and the second laminate is 3,000 to 4,000 MPa. The transmissivity variable optical laminate according to Claim 1.

3. The compression elastic modulus of the spacer is 2,000 to 5,500 MPa. The transmissivity variable optical laminate according to Claim 1.

4. The spacer includes one or more selected from the group consisting of a ball spacer and a column spacer. The transmissivity variable optical laminate according to Claim 1.

5. 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 transmissivity variable optical laminate according to Claim 1.

6. At least one of the first transparent conductive layer and the second transparent conductive layer includes one or more selected from the group consisting of a transparent conductive oxide, a metal, a carbon-based substance, a conductive polymer, a conductive ink, and a nanowire. The transmissivity variable optical laminate according to Claim 1.

7. Among the first polarizing plate and the second polarizing plate, at least one polarizing plate includes one or more selected from the group consisting of a functional coating layer, a protective layer, a retardation adjusting layer, a refractive index adjusting layer, and an overcoat layer. The variable transmittance optical laminate according to claim 1.

8. Among the first polarizing plate and the second polarizing plate, at least one polarizing plate has a thickness of 30 to 200 μm. The variable transmittance optical laminate according to claim 1.

9. The variable transmittance optical laminate according to claim 1, including a sealant disposed between the first laminate and the second laminate.

10. The variable transmittance optical laminate according to claim 1, further including one or more selected from the group consisting of an adhesive layer, an ultraviolet absorption layer, and an impact resistant layer.

11. A method for manufacturing the variable transmittance optical laminate according to any one of claims 1 to 10.

12. A smart window including the variable transmittance optical laminate according to any one of claims 1 to 10.

13. A means of transportation including the smart window according to claim 12.

14. An automobile in which the smart window according to claim 12 is applied to at least one of a front window, a rear window, a side window, a sunroof window, and an interior partition.

15. A wearable device including the smart window according to claim 12.

16. Architectural fixtures including the smart window according to claim 12.

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