Optical laminate, manufacturing method thereof, and smart window including the same

Abstract

The present invention relates to a variable transmittance optical stack, a manufacturing method thereof, and a smart window including the same, the variable transmittance optical stack including: a first stack including a first polarizer, one or more column spacers formed on one side of the first polarizer, a first transparent conductive layer formed on the first polarizer with the one or more column spacers formed thereon, and a first alignment film formed on the first transparent conductive layer; a second stack facing the first stack, in which a second polarizer, a second transparent conductive layer, and a second alignment film are stacked in this order; and a liquid crystal layer disposed between the first alignment film and the second alignment film, wherein the column spacers have an inclination angle that is an acute angle between a tangent to a side of the column spacer and the first polarizer.

Description

[Technical Field]

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

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

[0003] The variable transmittance optical stack is driven by applying a voltage to drive the liquid crystal to change the transmittance. The variable transmittance optical stacks developed to date are manufactured by forming a conductive layer for driving the liquid crystal on a separate substrate and combining it with other elements such as a polarizer.

[0004] For example, Japanese Patent Publication No. 2018-010035 also discloses a variable transmittance optical laminate including a transparent electrode layer formed on a polycarbonate (PC) substrate or the like having a predetermined thickness.

[0005] However, if a separate substrate is used to form the conductive layer, the manufacturing process becomes complicated, increasing manufacturing costs. In addition, the thickness of the laminate increases, causing a phase difference, which can result in changes in transmittance.

[0006] Therefore, there is a need to develop a variable transmittance optical stack that does not include a separate substrate for forming a conductive layer, thereby simplifying the manufacturing process and reducing the thickness, and that is capable of separately driving certain regions of the liquid crystal layer.

[0007] Furthermore, the variable transmittance optical stack includes two stacks, and a liquid crystal layer is disposed between the two stacks. Spacers are positioned to maintain a constant distance between the two stacks. Spacers are classified into ball spacers and column spacers depending on their shape and arrangement.

[0008] Although the ball spacers can be contained in the liquid crystal layer through a conventional spraying process, there are problems in that the ball spacers interfere with the alignment of the liquid crystal, and the ball spacers may gather together. In addition, the ball spacers may flow into the adhesive area of ​​the sealant, reducing the adhesive strength of the sealant, causing the liquid crystal to flow out of the panel and causing defects.

[0009] Meanwhile, when column spacers are formed in the liquid crystal layer, they are arranged on the conductive layer through a photolithography process and then coated with an alignment film. At this time, there is a problem that a residual film remaining after the photolithography process may cause a current disconnection between the conductive layer and the alignment film, and there is a problem that a coating solvent may penetrate into the column spacers when the alignment film is coated on top of the column spacers, causing deformation.

[0010] Furthermore, when an alignment layer is first formed on a conductive layer and then column spacers are formed on the alignment layer through a photolithography process, the performance of the alignment layer may change due to exposure to ultraviolet (UV) rays, resulting in defects.

[0011] Therefore, since a separate substrate for forming a conductive layer is not included, the manufacturing process can be simplified and the thickness can be reduced, and cracks or scratches that may occur during the process can be prevented, so there is a need to develop a variable transmittance optical laminate that does not reduce spacer reliability and improves liquid crystal appearance defects. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Japanese Patent Application Publication No. 2018-010035 Summary of the Invention [Problem to be solved by the invention]

[0013] An object of the present invention is to provide a variable transmittance optical laminate that is highly reliable when driving liquid crystal by preventing deformation of spacers, changes in the performance of alignment films, and occurrence of liquid crystal defects.

[0014] Another object of the present invention is to provide a variable transmittance optical laminate that does not require a separate substrate for forming a conductive layer, thereby simplifying the manufacturing process.

[0015] Another object of the present invention is to provide a variable transmittance optical laminate that does not include a separate substrate for forming a conductive layer, thereby significantly reducing the thickness.

[0016] Another object of the present invention is to provide a variable transmittance optical laminate that does not include a separate substrate for forming a conductive layer, thereby improving transmittance in a transmission mode.

[0017] Another object of the present invention is to provide a smart window including the variable transmittance optical laminate.

[0018] However, the problems to be solved by the present invention are not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

[0019] Another object of the present invention is to provide a variable transmittance optical laminate that includes at least one reflective polarizing plate, thereby improving the variable transmittance range between the light-transmitting mode and the light-blocking mode. [Means for solving the problem]

[0020] The present invention relates to a variable transmittance optical stack including: a first stack including a first polarizing plate, one or more column spacers formed on one side of the first polarizing plate, a first transparent conductive layer formed on the first polarizing plate on which the one or more column spacers are formed, and a first alignment film formed on the first transparent conductive layer; a second stack facing the first stack, in which a second polarizing plate, a second transparent conductive layer, and a second alignment film are stacked in this order; and a liquid crystal layer disposed between the first alignment film and the second alignment film, wherein the column spacers have an inclination angle that is an acute angle formed by a tangent to a side of the column spacer and the first polarizing plate.

[0021] In the first aspect of the present invention, the column spacer may have an inclination angle of 70° or less.

[0022] In the second aspect of the present invention, the column spacer may have a height of 2 to 10 μm and an upper width of 4 to 60 μm.

[0023] In the third aspect of the present invention, the area of ​​the upper part of the column spacer may be 0.2 to 5.0% of the area of ​​the second polarizer.

[0024] In a fourth aspect of the present invention, at least one of the first alignment film and the second alignment film may have a thickness of 30 to 300 nm.

[0025] In a fifth aspect of the present invention, at least one of the first alignment film and the second alignment film may be driven in one or more modes selected from TN (Twisted nematic) mode, STN (Super twisted nematic) mode, and VA (Vertical alignment) mode.

[0026] 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 functional layers selected from the group consisting of a protective layer, a retardation adjusting layer, and a refractive index adjusting layer.

[0027] 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.

[0028] In an eighth aspect of the present invention, the first transparent conductive layer may be formed in direct contact with a first polarizer on which the column spacers are formed, without any additional substrate between the first transparent conductive layer and the first polarizer, and the second transparent conductive layer may be formed in direct contact with the second polarizer, without any additional substrate between the second transparent conductive layer and the second polarizer.

[0029] In a ninth aspect of the present invention, the first transparent conductive layer may be formed on a first polarizer on which the column spacers are formed, and include an easy-adhesion layer, and the second transparent conductive layer may be formed on the second polarizer, and include an easy-adhesion layer.

[0030] In a tenth aspect of the present invention, at least one of the first transparent conductive layer and the second transparent conductive layer may contain one or more materials selected from the group consisting of transparent conductive oxides, metals, carbon-based materials, conductive polymers, conductive inks, and nanowires.

[0031] In an eleventh aspect of the present invention, the variable transmittance optical laminate may further include one or more layers selected from the group consisting of an adhesive layer, an ultraviolet absorbing layer, and a hard coating layer.

[0032] In a twelfth aspect of the present invention, the adhesive layer may be formed using one or more adhesives selected from an acrylic adhesive, a rubber adhesive, a silicone adhesive, a urethane adhesive, a polyvinyl alcohol adhesive, a polyvinylpyrrolidone adhesive, a polyacrylamide adhesive, a cellulose adhesive, a vinyl alkyl ether adhesive; and a photocurable adhesive.

[0033] The present invention also relates to a method for producing the variable transmittance optical laminate. The present invention also relates to a smart window comprising the variable transmittance optical laminate. [Effects of the Invention]

[0034] The variable transmittance optical laminate according to the present invention can be made highly reliable when driving the liquid crystal by preventing deformation of the spacers, changes in the performance of the alignment film, and occurrence of liquid crystal defects.

[0035] Furthermore, according to the variable transmittance optical laminate of the present invention, it is possible to omit the steps of forming a conductive layer on a substrate and then bonding it to other components, which are required to form a conventional optical laminate, and therefore the manufacturing process can be simplified compared to conventional optical laminates.

[0036] In addition, according to the variable transmittance optical laminate of the present invention, the conductive layer is formed directly on one side of the polarizer, and a separate substrate for forming the conductive layer is not required, so the thickness can be significantly reduced compared to conventional optical laminates.

[0037] In addition, according to the variable transmittance optical laminate of the present invention, a conductive layer is formed directly on one side of a polarizer, and a separate substrate for forming the conductive layer is not required, so that the transmittance in the transmission mode can be improved compared to conventional optical laminates.

[0038] In addition, the variable transmittance optical laminate according to the present invention includes at least one reflective polarizer, which can improve the variable transmittance range between the light-transmitting mode and the light-blocking mode compared to conventional optical laminates. [Brief explanation of the drawings]

[0039] [Figure 1] FIG. 1 is a diagram showing a layer structure of a variable transmittance optical layered body according to an embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged view of region M of the present invention. [Figure 3] FIG. 3 is a diagram showing a layer structure of a variable transmittance optical layered body according to another embodiment of the present invention. [Figure 4] FIG. 4 is a diagram illustrating a stacked structure of a smart window 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 6] FIG. 6 is a diagram showing the appearance of a portion where black amorphous irregularities occur in a variable transmittance optical laminate. [Figure 7] FIG. 7 is a diagram showing the appearance of a portion where liquid crystal unevenness occurs on the surface of the variable transmittance optical laminate. [Figure 8] FIG. 8 is a diagram showing the appearance of a portion where light leakage occurs on the surface of the variable transmittance optical laminate. DETAILED DESCRIPTION OF THE INVENTION

[0040] The present invention relates to a variable transmittance optical stack including at least one column spacer on a polarizer. Specifically, the present invention relates to a variable transmittance optical stack that has one or more column spacers formed on one side of a polarizer and a conductive layer for driving liquid crystal directly formed on the polarizer with the column spacers, thereby ensuring the durability of the column spacers and providing excellent reliability when driving liquid crystal, and that does not require a separate substrate for forming the conductive layer, thereby reducing the thickness of the stack and improving the transmittance in a transmission mode.

[0041] More specifically, the present invention relates to a variable transmittance optical stack including: a first stack including a first polarizing plate, one or more column spacers formed on one side of the first polarizing plate, a first transparent conductive layer formed on the first polarizing plate on which the one or more column spacers are formed, and a first alignment film formed on the first transparent conductive layer; a second stack facing the first stack, in which a second polarizing plate, a second transparent conductive layer, and a second alignment film are stacked in this order; and a liquid crystal layer disposed between the first alignment film and the second alignment film, wherein the column spacers have an inclination angle that is an acute angle formed by a tangent to the first polarizing plate.

[0042] 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.

[0043] 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.

[0044] Smart windows can be used to divide the interior space of vehicles and buildings or as partitions for privacy, 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 be used to replace glass in vehicles such as windows or sunroofs in automobiles, buses, airplanes, ships, or trains.

[0045] The variable transmittance optical laminate of the present invention can also be used in smart windows in the various technical fields mentioned above, and since the conductive layer is formed directly on the polarizer and therefore does not require a separate substrate for forming the conductive layer, it is thin and has advantageous bending properties, and various modes can be realized by including multiple unit electrodes, making it particularly suitable for use in smart windows for vehicles or buildings. In one or more embodiments, a smart window using the variable transmittance optical laminate of the present invention can be used in transportation, for example, the front window, rear window, side window, and sunroof window of an automobile, or as building fixtures, and in addition to blocking external light, it can also be used as an interior partition or for dividing the interior space of an automobile or building or for privacy protection.

[0046] 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, together with the above-described invention content, serve to further understand the technical concept of the present invention, and therefore the present invention should not be interpreted as being limited only to the matters depicted in these drawings.

[0047] 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 in the phrase. For example, as used herein, a "polarizer" may refer to at least one polarizer of the first polarizer and the second polarizer, a "transparent conductive layer" may refer to at least one transparent conductive layer of the first conductive layer and the second conductive layer, and an "alignment film" may refer to at least one alignment film of the first alignment film and the second alignment film.

[0048] 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.

[0049] 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" may 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.

[0050] As used herein, the "planar direction" can be interpreted as the normal direction of the polarizer and / or transparent conductive layer, ie, the direction viewed from the user's viewing side.

[0051] <Variable transmittance optical laminate> Fig. 1 is a diagram showing the layer structure of a variable transmittance optical laminate according to one embodiment of the present invention, Fig. 2 is an enlarged view of region M of the present invention, Fig. 3 is a diagram showing the layer structure of a variable transmittance optical laminate according to another embodiment of the present invention, and Fig. 4 and Fig. 5a to Fig. 5b are diagrams showing the layer structure of a smart window according to one or more embodiments of the present invention.

[0052] Referring to FIG. 1, a variable transmittance optical stack according to one embodiment of the present invention includes a first stack 100, a second stack 200, and a liquid crystal layer 300, wherein the first stack 100 includes a first polarizer 110-1, a column spacer 150, a first transparent conductive layer 210-1, and a first alignment film 310-1, and the second stack 200 may include a second polarizer 110-2, a second transparent conductive layer 210-2, and a second alignment film 310-2.

[0053] The polarizing plate 110 includes a polarizer, and may include a stretched polarizer or may be provided as a stretched polarizer. 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, as well as copolymers of vinyl acetate with other monomers copolymerizable therewith. The other monomers may be unsaturated carboxylic acids, unsaturated sulfonic acids, olefins, vinyl ethers, acrylamide monomers having an ammonium group, and the like. The polyvinyl alcohol (PVA)-based resin may also be modified, such as polyvinyl formal or polyvinyl acetal modified with aldehydes.

[0054] The polarizing plate 110 may also include a coating type polarizer. In one embodiment, the coating type polarizer may be formed using a liquid crystal coating composition, for example, by coating the liquid crystal coating composition on the upper surface of the protective layer. In this case, the liquid crystal coating composition may include a reactive liquid crystal compound and a dichroic dye.

[0055] The reactive liquid crystal compound may include a reactive mesogen (RM) capable of exhibiting liquid crystallinity and / or a monomer molecule having a polymerizable terminal functional group and forming a liquid crystal structure after a thermal or photocrosslinking reaction. When the reactive liquid crystal compound is polymerized by light or heat, a polymer network can be formed while maintaining the liquid crystal alignment. By using the reactive liquid crystal compound, a thin-film polarizer with improved mechanical and thermal stability can be formed while maintaining the optical anisotropy and dielectric constant characteristics of the liquid crystal.

[0056] The dichroic dye is a component included 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 a conventional or later-developed dichroic dye, such as an acridine dye, an oxazine dye, a cyanine dye, a naphthalene dye, an azo dye, or an anthraquinone dye, which may be used alone or in combination.

[0057] 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 labeling agent, a polymerization initiator, etc., within a range that does not impair the polarization properties of the coating film.

[0058] The polarizer 110 may have a curved shape in order to manufacture an optical laminate having a curved surface. For example, the polarizer 110 may be formed in a curved shape toward one of two different polarizers 110 stacked on both sides of the liquid crystal layer 300.

[0059] It is preferable that the transmission axis of the first polarizer 110-1 and the transmission axis of the second polarizer 110-2 are arranged perpendicular to each other in the planar direction, which can be advantageous in improving the transmittance variable range between the light-transmitting mode and the light-blocking mode of the optical laminate by driving the liquid crystal.

[0060] In one or more embodiments, at least one of the first polarizer 110-1 and the second polarizer 110-2 may further include one or more functional layers selected from the group consisting of a protective layer, a phase difference adjusting layer, and a refractive index adjusting layer.

[0061] The protective layer protects the polarization characteristics of the polarizer from post-processing and external environments, and may be embodied in the form of a protective film.

[0062] The protective layer may be used as a multi-layer structure in which one or more protective layers are continuously laminated, or may be used in combination with other functional layers.

[0063] In one or more embodiments, the protective film 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).

[0064] The retardation control layer complements the optical properties of the optical laminate and may be implemented in the form of a retardation film, etc., and may be a conventional or later-developed retardation film, etc. For example, a quarter-wave plate (1 / 4 wave plate) or a half-wave plate (1 / 2 wave plate) for delaying the phase of light may be used, and these may be used alone or in combination.

[0065] The retardation adjusting layer 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.

[0066] 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 resins, 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 among the monomers forming the polymers.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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, and 0.1 to 5 μm in the case of a liquid crystal polymer film.

[0071] The refractive index adjustment layer is provided to compensate for a refractive index difference of the optical laminate caused by the transparent conductive layer 210, and may serve to improve visibility by reducing the refractive index difference. The refractive index adjustment layer may also be provided to correct a color caused by the transparent conductive layer 210. Meanwhile, when the transparent conductive layer has a pattern, the refractive index adjustment layer can compensate for a transmittance difference between a patterned region where the pattern is formed and a non-patterned region where the pattern is not formed.

[0072] Specifically, the transparent conductive layer 210 is stacked adjacent to another member having a different refractive index, and the difference in refractive index between the adjacent layers may cause a difference in light transmittance. In particular, when a pattern is formed on the transparent conductive layer, a problem may occur in which the patterned region and the non-patterned region are visually distinguishable. Therefore, by including the refractive index control layer, the refractive index is compensated for, thereby reducing the difference in light transmittance of the optical laminate. In particular, when a pattern is formed on the transparent conductive layer, the patterned region and the non-patterned region are visually distinguishable.

[0073] In one embodiment, the refractive index of the refractive index adjusting layer may be appropriately selected depending on the material of the adjacent member, and is 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 210 and the other member, such as a polarizer.

[0074] The refractive index adjustment layer is not particularly limited as long as it can prevent a sharp difference in refractive index between other components and the transparent conductive layer 210, and may be formed from a compound used to form a conventional or later-developed refractive index adjustment layer, for example, a refractive index adjustment layer-forming composition containing a polymerizable isocyanurate compound.

[0075] In one embodiment, the polarizer 110 may further include other functional layers in addition to the above-mentioned functional layers to support or enhance the properties of the polarizer, for example, an overcoat layer to further improve mechanical durability.

[0076] In one or more embodiments, the polarizer 110 may have a thickness of 30 to 200 μm, preferably 30 to 170 μm, and more preferably 50 to 150 μm, which allows the polarizer 110 to maintain its optical properties and allows for the manufacture of a thin optical laminate.

[0077] The present invention may include one or more column spacers 150 on one surface of the first polarizer 110-1.

[0078] The column spacers 150 support the second laminate 200 and maintain a constant liquid crystal cell gap, thereby ensuring a space for the liquid crystal layer 300 (described later) between the first laminate 100 and the second laminate 200, allowing for sufficient injection of the liquid crystal compound 350, and including a large number of column spacers 150 to provide a liquid crystal layer 300 of uniform thickness. This eliminates the need to mix separate ball spacers, prevents problems such as ball spacers bunching together and the ball spacers interfering with the liquid crystal alignment, and prevents poor adhesion caused by the ball spacers flowing in when sealing with the sealant 450, and the resulting liquid crystal defects.

[0079] In addition, the transparent conductive layer 210-1 described below is laminated on the column spacer 150, and the first alignment film 310-1 is not directly coated on the column spacer 150, so that it is possible to prevent problems with the spacer shape caused by deformation of the spacer resin due to penetration of the coating liquid composition when coating the first alignment film 310-1.

[0080] In addition, since the transparent conductive layer 210-1 described later is stacked on the column spacer 150 and the first alignment film 310-1 is coated on it, there is no risk of current being disconnected between the transparent conductive layer and the alignment film due to residual film that is not completely removed after the column spacer 150 is formed.

[0081] Furthermore, since the first alignment film 310-1 is formed after the column spacers 150 are formed, defects caused by changes in the alignment performance of the alignment film due to UV irradiation during the column spacer 150 formation process can be prevented.

[0082] The column spacer 150 may have an inclination angle a, which is an acute angle formed between a tangent P of the side s and the first polarizer 110-1.

[0083] The inclination angle a may be an acute angle in consideration of thickness variations of the transparent conductive layer 210-1 formed on the first polarizer 110-1 and the column spacers 150, and is preferably 70° or less, more preferably 20 to 70°, and most preferably 30 to 60°. The transparent conductive layer 210-1 (described below) formed on the first polarizer 110-1 on which the column spacers 150 are formed may be formed by a process such as deposition, printing, or plating of a transparent conductive oxide having a visible light transmittance of 50% or more. However, if the inclination angle a does not satisfy the above range, problems may occur in the uniform formation of the transparent conductive layer 210-1, and image retention may occur when the optical stack is switched between a light-transmitting mode and a light-blocking mode by driving the liquid crystal. For example, if the inclination angle a is a right angle or an obtuse angle, the transparent conductive layer 210-1 may not be formed in part or may be formed unevenly on the side portion s of the column spacer 150. If the transparent conductive layer 210-1 is not partially formed on the side s of the column spacer 150, a short circuit may occur in the transparent conductive layer, causing defects when the liquid crystal is driven. If the transparent conductive layer 210-1 is not formed uniformly, there may be a problem of afterimages occurring when the liquid crystal is driven due to differences in response speed.

[0084] The column spacer 150 may have any shape as long as the angle between the tangent P of the side s and the first polarizer 110-1 is an acute angle a. For example, any of a cylindrical shape, a polygonal prism shape, a cone shape, a polygonal pyramid shape, a hemisphere shape, a mesh shape, and other shapes may be used.

[0085] Since the column spacer 150 includes an inclination angle a, which is an acute angle, the longitudinal section may have a shape as shown in Fig. 2, but is not limited thereto. In Fig. 2, the column spacer 150 is shown with a shape in which the side s is straight, but is not particularly limited thereto as long as the shape can achieve the technical effect aimed at by the present invention, and may have, for example, a curved shape or a layered shape.

[0086] That is, the width of the column spacer 150 may become thinner from the portion contacting the first polarizer 110-1 toward the top. However, taking into consideration the process streamlining during the spacer manufacturing process and the size that minimizes apparent visibility in the transmission mode, when the portion contacting the first polarizer 110-1 is the bottom of the column spacer, the width d of the top of the column spacer facing this may be 4 to 60 μm.

[0087] The column spacer 150 may have a height h of 2 to 10 μm. If the height h of the column spacer 150 is less than 2 μm, the liquid crystal may be significantly affected by the surface anchoring energy of the substrate, which may prevent the liquid crystal from twisting when a voltage is applied. Also, if the height h of the column spacer 150 exceeds 10 μm, light leakage may occur due to viewing angle characteristics.

[0088] If the number of column spacers 150 is small, the liquid crystal cell gap in a portion of the liquid crystal layer may be reduced, causing the portion to appear as black amorphous unevenness to the user, while if the number of column spacers 150 is large, the transmittance (%) may be reduced when no voltage is applied. In consideration of these points, the area of ​​the upper portion of the column spacers 150 may be 0.2 to 5.0% of the area of ​​the second polarizer 110-2.

[0089] The column spacers 150 may be formed by applying a photosensitive resin composition to the first polarizer 110-1, drying the composition to form a coating film, and then exposing and developing the coating film to form a column spacer 150 pattern.

[0090] The coating method may be a coating method such as roll coating, spin coating, slit coating, inkjet printing, or a printing process.

[0091] The photosensitive resin composition for the column spacer 150 may contain a binder resin, a photopolymerizable compound, a photopolymerization initiator, and a solvent.

[0092] The binder resin is a component that imparts solubility to an alkaline developer used in the developing process, and any binder resin can be used as long as it is soluble in the alkaline developer. The binder resin is soluble in the alkaline developer used in the developing process for forming a pattern, and in order to improve low-temperature curing properties, the binder resin can be prepared by copolymerizing an ethylenically unsaturated monomer having a carboxyl group, or by polymerizing an ethylenically unsaturated monomer having a carboxyl group and a copolymerizable unsaturated monomer.

[0093] Specific examples of the ethylenically unsaturated monomer having a carboxyl group include monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; dicarboxylic acids such as fumaric acid, mesaconic acid, and itaconic acid; and anhydrides of the dicarboxylic acids; and mono(meth)acrylates of polymers having a carboxyl group and a hydroxyl group at both ends, such as ω-carboxypolycaprolactone mono(meth)acrylate, with acrylic acid and methacrylic acid being preferred.

[0094] Specific examples of the copolymerizable unsaturated polymerizable monomer include: Glycidyl methacrylate, which is an unsaturated monomer having a glycidyl group; ethylenically unsaturated monomers having a hydroxyl group, such as hydroxyethyl (meth)acrylates, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, and N-hydroxyethyl acrylamide; Aromatic vinyl compounds such as styrene, vinyltoluene, α-methylstyrene, p-chlorostyrene, o-methoxystyrene, m-methoxystyrene, p-methoxystyrene, o-vinylbenzyl methyl ether, m-vinylbenzyl methyl ether, p-vinylbenzyl methyl ether, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, and p-vinylbenzyl glycidyl ether; N-substituted maleimide compounds such as N-cyclohexylmaleimide, N-benzylmaleimide, N-phenylmaleimide, No-hydroxyphenylmaleimide, Nm-hydroxyphenylmaleimide, Np-hydroxyphenylmaleimide, No-methylphenylmaleimide, Nm-methylphenylmaleimide, Np-methylphenylmaleimide, No-methoxyphenylmaleimide, Nm-methoxyphenylmaleimide, and Np-methoxyphenylmaleimide; Alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, sec-butyl (meth)acrylate, and t-butyl (meth)acrylate; alicyclic (meth)acrylates such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-methylcyclohexyl (meth)acrylate, tricyclo[5.2.1.02,6]decan-8-yl (meth)acrylate, 2-dicyclofentanyloxyethyl (meth)acrylate, and isobornyl (meth)acrylate; aryl (meth)acrylates such as phenyl (meth)acrylate and benzyl (meth)acrylate; Unsaturated oxetane compounds such as 3-(methacryloyloxymethyl)oxetane, 3-(methacryloyloxymethyl)-3-ethyloxetane, 3-(methacryloyloxymethyl)-2-trifluoromethyloxetane, 3-(methacryloyloxymethyl)-2-phenyloxetane, 2-(methacryloyloxymethyl)oxetane, 2-(methacryloyloxymethyl)-4-trifluoromethyloxetane; and the like.

[0095] As the copolymerizable polymerizable monomer having an unsaturated bond, glycidyl methacrylate and tetrahydrofuryl methacrylate, which are unsaturated monomers having a glycidyl group, are preferred.

[0096] The copolymerizable unsaturated monomers may be used either alone or in combination of two or more.

[0097] The content of the binder resin is 3 to 40 wt %, preferably 3 to 20 wt %, based on the total weight of the photosensitive resin composition. When the content of the binder resin is within this range, the solubility in the developer is sufficient, facilitating pattern formation, preventing film reduction in pixel areas of exposed areas during development, and improving leakage resistance in non-pixel areas, which is preferable.

[0098] In order to ensure the development property of the photosensitive resin composition, the acid value of the binder resin is preferably 30 to 150 mgKOH / g. If the acid value of the binder resin is less than 30 mgKOH / g, it is difficult to ensure a sufficient development speed of the photosensitive resin composition, and if it exceeds 150 mgKOH / g, adhesion to the substrate decreases, making it easy for short circuits to occur in the pattern.

[0099] The photopolymerizable compound is a compound that can be polymerized by the action of the following photopolymerization initiator, and a monofunctional monomer, a bifunctional monomer, or a polyfunctional monomer can be used, and it is preferable to use a polyfunctional monomer having two or more functionalities.

[0100] Specific examples of the monofunctional monomer include, but are not limited to, nonylphenyl carbitol acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-ethylhexyl carbitol acrylate, 2-hydroxyethyl acrylate, and N-vinylpyrrolidone.

[0101] Specific examples of the bifunctional monomer include, but are not limited to, 1,6-hexanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, bis(acryloyloxyethyl) ether of bisphenol A, and 3-methylpentanediol di(meth)acrylate.

[0102] Specific examples of the polyfunctional monomer include, but are not limited to, trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetr(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexaacrylate, ethoxylated dipentaerythritol hexa(meth)acrylate, propoxylated dipentaerythritol hexa(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0103] The photopolymerizable compound may be contained in an amount of 5 to 50 wt %, preferably 7 to 45 wt %, and more preferably 10 to 20 wt %, based on the total weight of the photosensitive resin composition. When the photopolymerizable compound is contained within this range, the strength and smoothness of the spacer are improved, which is preferable.

[0104] The photopolymerization initiator is a compound that generates radicals that can initiate polymerization of the photopolymerizable compound when exposed to radiation such as visible light, ultraviolet light, atomic rays, electron beams, or X-rays.

[0105] The photopolymerization initiator contains an oxime ester-based photopolymerization initiator as an essential component. Examples of the oxime ester compounds include 2-O-benzoyloxime-1-[4-(phenylthio)phenyl]-1,2-octanedione and 1-[9-Ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone 1-(O-acetyloxime). Commercially available oxime ester photopolymerization initiators include Irgacure® OXE01, Irgacure® OXE02, and Irgacure® OXE03 manufactured by BASF. Since each of these compounds has a different absorbance and generates different radical species, it is preferable to use two or more of them in combination.

[0106] In addition, a photopolymerization initiator other than the oxime ester-based photopolymerization initiator can be additionally used in combination. Typically, it is preferable to use one or more compounds selected from the group consisting of acetophenone-based compounds, benzophenone-based compounds, triazine-based compounds, biimidazole-based compounds, and thioxanthone-based compounds.

[0107] Specific examples of the acetophenone-based compound include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyl dimethyl ketal, 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one, 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propan-1-one, and 2-(4-methylbenzyl)-2-(dimethylamino)-1-(4-morpholinophenyl)butan-1-one.

[0108] Examples of the benzophenone compounds include benzophenone, methyl 0-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone, and 2,4,6-trimethylbenzophenone.

[0109] Specific examples of the triazine-based compound include 2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxynaphthyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-piperonyl-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxystyryl)-1,3,5-triazine, and 2,4-bis(trichloromethyl)-6- [2-(5-methylfuran-2-yl)ethenyl]-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(furan-2-yl)ethenyl]-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(4-diethylamino-2-methylphenyl)ethenyl]-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(3,4-dimethoxyphenyl)ethenyl]-1,3,5-triazine, and the like.

[0110] Specific examples of the biimidazole compound include 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole, 2,2'-bis(2,3-dichlorophenyl)-4,4',5,5'-tetraphenylbiimidazole, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetra(alkoxyphenyl)biimidazole, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetra(trialkoxyphenyl)biimidazole, 2,2-bis(2,6-dichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, and imidazole compounds in which the phenyl groups at the 4,4',5,5' positions are substituted with carboalkoxy groups. Of these, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole, 2,2'-bis(2,3-dichlorophenyl)-4,4',5,5'-tetraphenylbiimidazole, and 2,2-bis(2,6-dichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole are preferably used.

[0111] Examples of the thioxanthone compounds include 2-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, and 1-chloro-4-propoxythioxanthone.

[0112] In addition, the photopolymerization initiator may further contain a photopolymerization initiation assistant to improve the sensitivity of the infrared transparent photosensitive resin composition. By including the photopolymerization initiation assistant, the infrared transparent photosensitive resin composition according to the present invention can further increase sensitivity and improve productivity.

[0113] As the photopolymerization initiation aid, for example, one or more compounds selected from the group consisting of amine compounds, carboxylic acid compounds, and polyfunctional thiol compounds having a thiol group may be preferably used.

[0114] As the amine compound, it is preferable to use an aromatic amine compound. Specifically, aliphatic amine compounds such as triethyl alcoholamine, methyldiethanolamine, and triisopropanolamine, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2-dimethylaminoethyl benzoate, N,N-dimethyl-p-toluidine, 4,4'-bis(dimethylamino)benzophenone (commonly known as Michler's ketone), and 4,4'-bis(diethylamino)benzophenone may be used.

[0115] The carboxylic acid compound is preferably an aromatic heteroacetic acid, and specific examples thereof include phenylthioacetic acid, methylphenylthioacetic acid, ethylphenylthioacetic acid, methylethylphenylthioacetic acid, dimethylphenylthioacetic acid, methoxyphenylthioacetic acid, dimethoxyphenylthioacetic acid, chlorophenylthioacetic acid, dichlorophenylthioacetic acid, N-phenylglycine, phenoxyacetic acid, naphthylthioacetic acid, N-naphthylglycine, and naphthoxyacetic acid.

[0116] Examples of the polyfunctional thiol compound having a thiol group include 2-mercaptobenzothiazole, 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(3-mercaptobutyloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), pentaerythritol tetrakis(3-mercaptopropionate), dipentaerythritol hexakis(3-mercaptopropionate), and tetraethylene glycol bis(3-mercaptopropionate).

[0117] In addition, the photopolymerization initiator may further include a photopolymerization initiation assistant to improve the sensitivity of the photosensitive resin composition. By including the photopolymerization initiation assistant, the photosensitive resin composition can further increase its sensitivity and improve productivity.

[0118] The photopolymerization initiation aid may preferably be, for example, one or more compounds selected from the group consisting of amine compounds, carboxylic acid compounds, and polyfunctional thiol compounds.

[0119] As the amine compound, it is preferable to use an aromatic amine compound. Specifically, aliphatic amine compounds such as triethyl alcoholamine, methyldiethanolamine, and triisopropanolamine, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2-dimethylaminoethyl benzoate, N,N-dimethyl-p-toluidine, 4,4'-bis(dimethylamino)benzophenone (commonly known as Michler's ketone), and 4,4'-bis(diethylamino)benzophenone may be used.

[0120] The carboxylic acid compound is preferably an aromatic heteroacetic acid, and specific examples thereof include phenylthioacetic acid, methylphenylthioacetic acid, ethylphenylthioacetic acid, methylethylphenylthioacetic acid, dimethylphenylthioacetic acid, methoxyphenylthioacetic acid, dimethoxyphenylthioacetic acid, chlorophenylthioacetic acid, dichlorophenylthioacetic acid, N-phenylglycine, phenoxyacetic acid, naphthylthioacetic acid, N-naphthylglycine, and naphthoxyacetic acid.

[0121] Examples of the polyfunctional thiol compound include Tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, Trimethylolpropane tris-3-mercaptopropionate, Pentaerythritol tetrakis-3-mercaptopropionate, and Dipentaerythritol hexa-3-mercaptopropionate.

[0122] The photopolymerization initiator may be included in an amount of 1 to 20 wt %, preferably 1 to 10 wt %, based on the total weight of the photosensitive resin composition. When the photopolymerization initiator content is within the above range, the photosensitive resin composition becomes highly sensitive, shortening the exposure time and improving productivity, which is preferable. Furthermore, the strength and surface smoothness of the spacer formed using the composition according to the above conditions can be improved. Furthermore, in the case of the oxime ester-based photopolymerization initiator, it should be included in an amount of 10 to 100 wt %, preferably 20 to 100 wt %, of the total photopolymerization initiator. If the proportion of the oxime ester-based photopolymerization initiator in the total photopolymerization initiator is less than 10 wt %, the decrease in sensitivity due to the dye cannot be overcome, and pattern shorting is likely to occur during the development process.

[0123] In addition, when the photopolymerization initiator assistant is further used, the photopolymerization initiator assistant may be included in an amount of 0.1 to 40 parts by weight, preferably 1 to 30 parts by weight, based on 100 parts by weight of the total of the binder resin and the photopolymerizable compound, based on the solid powder. When the amount of the photopolymerization initiator assistant used is within the above-mentioned range of 0.1 to 40 parts by weight, the sensitivity of the photosensitive resin composition is further increased, thereby improving the productivity of spacers formed using the composition.

[0124] The solvent used for the binder resin may be any solvent that is effective in dissolving other components contained in the photosensitive resin composition, but from the viewpoint of coatability and drying property, an organic solvent having a boiling point of 100° C. to 200° C. is preferred. More preferred are propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, cyclohexanone, ethyl lactate, butyl lactate, ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, etc., and further preferred are solvents such as propylene glycol monomethyl ether acetate and / or 4-hydroxy-4-methyl-2-pentanone.

[0125] In addition to the above solvent, a solvent that is effective for dissolving other components contained in the photosensitive resin composition and is generally used in photosensitive resin compositions can be added. In particular, ethers, aromatic hydrocarbons, ketones, alcohols, esters, amides, etc. are preferred.

[0126] Specifically, ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, and ethylene glycol monobutyl ether; diethylene glycol dialkyl ethers such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, and diethylene glycol dibutyl ether; ethylene glycol alkyl ether acetates such as methyl cellulosolve acetate and ethyl cellulosolve acetate; Examples of suitable esters include alkylene glycol alkyl ether acetates such as propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, methoxybutyl acetate, and methoxypentyl acetate; aromatic hydrocarbons such as benzene, toluene, xylene, and mesitylene; ketones such as methyl ethyl ketone, acetone, methyl amyl ketone, methyl isobutyl ketone, and cyclohexanone; alcohols such as ethyl alcohol, propanol, butanol, hexanol, cyclohexanol, ethylene glycol, and glycerin; esters such as ethyl 3-ethoxypropionate and methyl 3-methoxypropionate; and cyclic esters such as γ-butyrolactone.

[0127] The solvent may be included in an amount of 60 to 90 wt %, preferably 70 to 85 wt %, based on the total weight of the photosensitive resin composition. When the solvent is included in the amount of 60 to 90 wt %, good coatability is achieved when the composition is coated using a coating device such as a roll coater, spin coater, slit and spin coater, slit coater (sometimes called a die coater), or inkjet.

[0128] In addition to the above components, the photosensitive resin composition of the present invention may also contain additives such as antioxidants, fillers, other polymeric compounds, curing agents, adhesion promoters, ultraviolet absorbers, and anti-aggregation agents, as needed by those skilled in the art, within the scope of the object of the present invention.

[0129] Commercially available antioxidants include ADK STAB AO-30, ADK STAB AO-40, ADK STAB AO-50F, ADK STAB AO-60, ADK STAB AO-80, ADK STAB 1178, ADK STAB TPP, ADK STAB 1500, ADK STAB 135A, and ADK STAB 3010 manufactured by Adeka Corporation.

[0130] The filler may be specifically glass, silica, alumina, etc., but is not limited thereto.

[0131] Specific examples of the other polymer compounds that can be used include curable resins such as epoxy resins and maleimide resins, and thermoplastic resins such as polyvinyl alcohol, polyacrylic acid, polyethylene glycol monoalkyl ether, polyfluoroalkyl acrylate, polyester, and polyurethane, but are not limited thereto.

[0132] The curing agent is used to enhance deep curing and mechanical strength, and specifically, an epoxy compound, a polyfunctional isocyanate compound, a melamine compound, an oxetane compound, etc. can be used, but is not limited thereto.

[0133] Specific examples of the epoxy compounds include, but are not limited to, bisphenol A epoxy resins, hydrogenated bisphenol A epoxy resins, bisphenol F epoxy resins, hydrogenated bisphenol F epoxy resins, novolac epoxy resins, other aromatic epoxy resins, alicyclic epoxy resins, glycidyl ester resins, glycidyl amine resins, or brominated derivatives of these epoxy resins; aliphatic, alicyclic, or aromatic epoxy compounds other than epoxy resins and their brominated derivatives; butadiene (co)polymer epoxy compounds; isoprene (co)polymer epoxy compounds; glycidyl (meth)acrylate (copolymer); triglycidyl isocyanurate; and the oxetane compounds include, but are not limited to, carbonate bisoxetane, xylene bisoxetane, adipate bisoxetane, terephthalate bisoxetane, and cyclohexanedicarboxylic acid bisoxetane.

[0134] The curing agent can be used in combination with a curing auxiliary compound capable of ring-opening polymerization of the epoxy group of an epoxy compound or the oxetane skeleton of an oxetane compound. Specific examples of the curing auxiliary compound include polycarboxylic acids, polycarboxylic anhydrides, and acid generators. The carboxylic anhydrides can be commercially available epoxy resin curing agents. Examples of commercially available epoxy resin curing agents include those sold under the trade names ADEKA HARDNER EH-700 (manufactured by ADEKA Industrial Co., Ltd.), RIKACID HH (manufactured by New Japan Chemical Co., Ltd.), and MH-700 (manufactured by New Japan Chemical Co., Ltd.).

[0135] The curing agents and curing auxiliary compounds exemplified above can be used either alone or in combination of two or more.

[0136] Specific examples of the adhesion promoter include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltrimethoxysilane, and 3-isocyanatopropyltriethoxysilane, and these compounds may be used alone or in combination.

[0137] The ultraviolet absorber may be, for example, 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chlorobenzothiazole, alkoxybenzophenone, or the like, but is not limited thereto.

[0138] The anti-aggregating agent may be, but is not limited to, sodium polyacrylate.

[0139] The additive is preferably contained in an amount of 0.01 to 20% by weight, more preferably 0.1 to 10% by weight, based on the total weight of the photosensitive resin composition.

[0140] The exposure step can include ultraviolet exposure (eg, using a g-line, h-line, i-line, or KrF light source) using a mask and refractive elements to selectively expose the pixel areas.

[0141] The refractive element is disposed between the mask and the light source and changes the direction of the light beam from the light source. The refractive element may be a prism. According to Snell's law, the exit angle of the light beam can be adjusted relative to the incident angle of the light beam. The refractive index of the refractive element and the material of the photosensitive resin are selected to adjust the tilt angle a of the refractive element.

[0142] Thereafter, the non-exposed or exposed regions can be selectively removed using a developer to form the pattern having the desired pattern shape. That is, if the photosensitive resin composition for forming the column spacer 150 is a positive photoresist layer, the exposed photoresist is removed to obtain a transferred pattern having a predetermined inclination angle a. Conversely, if it is a negative photoresist layer, the exposed photoresist is strengthened by cross-linking, so the unexposed photoresist is removed to form a transferred pattern having a predetermined inclination angle a.

[0143] The developer may contain, for example, an inorganic or organic alkaline compound. Examples of inorganic alkaline compounds include sodium hydroxide, potassium hydroxide, disodium hydrogen phosphate, sodium dihydrogen phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, potassium dihydrogen phosphate, sodium silicate, potassium carbonate, sodium carbonate, sodium bicarbonate, potassium bicarbonate, sodium borate, potassium borate, and ammonia. Examples of organic alkaline compounds include tetramethylammonium hydroxide, 2-hydroxyethyltrimethylammonium hydroxide, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, and ethyl alcoholamine. These compounds may be used alone or in combination.

[0144] After the development process, the column spacer 150 pattern may be further hardened through an additional heat hardening process (post-baking, post-firing), in which the heating temperature may be 90 to 180°C and the heating time may be 5 to 180 minutes, preferably 15 to 90 minutes, but is not limited thereto.

[0145] As shown in the accompanying drawings, in the variable optical stack of the present invention, the column spacers 150 may be formed in the first stack 100, and the column spacers may also be formed in the second stack 200. When the second stack 200 also includes a column spacer, the position thereof is not particularly limited, and the column spacer may be formed in a position facing the column spacer 150 and in contact therewith, or may be formed in a position where the column spacer 150 of the first stack 100 is not formed and offset from the column spacer 150.

[0146] In this way, by including the column spacer 150, the present invention can prevent deformation of the column spacer and occurrence of liquid crystal defects, and can provide a variable transmittance optical laminate that is highly reliable when driving liquid crystal.

[0147] The transparent conductive layer 210 is provided for driving the liquid crystal layer 300. For example, as shown in FIG. 1, the first transparent conductive layer 210-1 may be formed in direct contact with the first polarizer 110-1 on which the column spacers 150 are formed, and the transparent conductive layer 210-2 may be formed in direct contact with the second polarizer 110-2 on which the column spacers 150 are not formed.

[0148] Conventional optical laminates used in the manufacture of smart windows, etc., are manufactured by forming a conductive layer for driving liquid crystals on one side of the substrate and laminating the other side of the substrate with a polarizer. However, the variable transmittance optical laminate according to the present invention does not require a separate substrate for forming the conductive layer, and 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 transmission mode.

[0149] In one embodiment, the transparent conductive layer 210 may be formed by direct deposition on the first polarizer 110-1 and the second polarizer 110-2 on which the column spacers 150 are formed. In this case, the transparent conductive layer 210 may be formed by directly contacting the pre-treated surface of the polarizer 110 and the column spacer 150 after pre-treating the polarizer 110 and the column spacer 150 with a corona treatment or a plasma treatment to improve adhesion between the polarizer 110 and the column spacer 150. 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.

[0150] In another embodiment, the transparent conductive layer 210 may be formed in direct contact with the polarizer 110 and the column spacer 150, with an easy-adhesion layer (not shown) provided on one side of the polarizer 110 and the column spacer 150 sandwiched therebetween, in order to improve the adhesive strength between the polarizer 110 and the column spacer 150.

[0151] The transparent conductive layer 210 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.

[0152] 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).

[0153] Alternatively, the transparent conductive layer 210 may be formed as a two-layer structure using a combination of 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.

[0154] The transparent conductive layer 210 may be formed by a method commonly used in the art, for example, by selecting an appropriate process from coating processes such as spin coating, roller coating, bar coating, dip coating, gravure coating, curtain coating, die coating, spray coating, doctor coating, and kneader coating; printing (coating) processes such as screen printing, spray printing, inkjet printing, relief printing, intaglio printing, and planographic printing; and deposition processes such as CVD (chemical vapor deposition), PVD (physical vapor deposition), and PECVD (plasma enhanced chemical vapor deposition).

[0155] The alignment film 310 may be formed on the transparent conductive layer 210 and is not particularly limited as long as it can impart alignment to the liquid crystal compound 350. For example, the alignment film 310 may be fabricated by applying and curing an alignment film coating composition including an alignment polymer, a photopolymerization initiator, and a solvent. The alignment polymer is not particularly limited, but may be a polyacrylate resin, a polyamic acid resin, a polyimide resin, a polymer containing a cinnamate group, or any other conventional or later-developed polymer capable of exhibiting alignment.

[0156] The first alignment film 310-1 is formed according to the shape of the column spacer 150, and therefore, a portion of the first alignment film 310-1 may contact the second alignment film 310-2, but they are not necessarily bonded together. That is, the first alignment film 310-1 and the second alignment film 310-2 may or may not contact each other, allowing the liquid crystal compound 350, which will be described later, to move between them.

[0157] At least one of the first alignment film 310-1 and the second alignment film 310-2 may have a thickness of 30 to 300 nm. If the thickness of the alignment film 310 is less than 30 nm, a current short circuit may occur, and if it exceeds 300 nm, an appropriate free tilt angle may not be achieved when a voltage is applied, resulting in a slow response speed and insufficient front blackout, which may result in liquid crystal unevenness and image retention.

[0158] The liquid crystal layer 300 can change the driving mode of the optical stack by adjusting the transmittance of light incident in one or more directions by an electric field.

[0159] The liquid crystal layer 300 may include a liquid crystal compound 350 and may be provided between the first polarizer 110-1 and the second polarizer 110-2 in the light control region, for example, and may be located in a space defined by the column spacers 150. The liquid crystal layer 300 may be disposed between the first stack 100 and the second stack 200, and may be disposed between the first alignment film 310-1 and the second alignment film 310-2. In this case, the first alignment film 310-1 and the second alignment film 310-2 may or may not abut each other depending on the shape of the column spacers 150, but it is preferable that they abut each other to maintain a uniform cell gap.

[0160] The liquid crystal compound 350 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 350 may be used. For example, the above-described reactive liquid crystal compound 350 of the coating-type polarizer may be similarly applied.

[0161] The liquid crystal behavior mode of the liquid crystal compound 350 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, etc.

[0162] In one embodiment, the liquid crystal layer 300 may be driven in a twisted nematic (TN) mode. In this case, the transmittance variable range between the light-transmitting mode and the light-blocking mode of the optical stack can be improved through optical design with the polarizer 110, which may be advantageous in terms of facilitating the upsizing of the optical stack.

[0163] A sealant 450 may be disposed across the liquid crystal layer 300 and the alignment film 310 . The sealant 450 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 450. The UV-curable resin may be a polymer of a UV-curable monomer. The thermosetting resin may be a polymer of a thermosetting monomer.

[0164] The base resin of the sealant 450 may be, for example, an acrylate-based resin, an epoxy 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 450 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 adjusted within the scope of the present application. The sealant 450 may further include an initiator, for example, a photoinitiator or a thermal initiator, if necessary.

[0165] The sealant 450 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.

[0166] The variable transmittance optical laminate of the present invention may further include other components within the scope of the present invention, for example, it may further include an adhesive layer 400 on one side (see FIG. 3) or both sides (not shown) of the optical laminate, or it may further include an ultraviolet absorbing layer, a hard coating layer, etc.

[0167] The adhesive layer 400 may be formed using an adhesive or pressure-sensitive adhesive, and may be formed on one or both sides of the optical laminate. It preferably has an appropriate adhesive strength to prevent peeling, bubbles, etc. from occurring when the optical laminate is handled, as well as transparency and thermal stability.

[0168] The adhesive may be a conventional or later-developed adhesive, and in one or more embodiments, may be an acrylic adhesive, a rubber adhesive, a silicone adhesive, a urethane adhesive, a polyvinyl alcohol adhesive, a polyvinylpyrrolidone adhesive, a polyacrylamide adhesive, a cellulose adhesive, a vinyl alkyl ether adhesive, etc. The adhesive is not particularly limited as long as it has adhesive strength and viscoelasticity, but from the viewpoint of availability, etc., it may preferably be an acrylic adhesive, which may contain, for example, a (meth)acrylate copolymer, a crosslinking agent, and a solvent.

[0169] 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.

[0170] The solvent may include conventional solvents used in the field of resin compositions, such as alcohol-based compounds such as methanol, ethyl alcohol, 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; cellulosolve-based compounds such as methyl cellulosolve, ethyl cellulosolve, and propyl cellulosolve; and hydrocarbon-based compounds such as hexane, heptane, benzene, toluene, and xylene. These may be used alone or in combination of two or more.

[0171] The adhesive may be a conventional or later-developed adhesive, for example, a photocurable adhesive. The photocurable adhesive exhibits strong adhesive strength by crosslinking and curing upon exposure to active energy rays such as ultraviolet (UV) or electron beams (EB). It may be composed of a reactive oligomer, a reactive monomer, a photopolymerization initiator, and the like. The reactive oligomer is an important component that determines the adhesive's properties and forms a hardened coating by forming polymer bonds through a photopolymerization reaction. Usable reactive oligomers include polyester-based resins, polyether-based resins, polyurethane-based resins, epoxy-based resins, polyacrylic resins, and silicone-based resins. The reactive monomer functions as a crosslinker or diluent for the reactive oligomer and affects the adhesive properties. Usable reactive monomers include monofunctional monomers, polyfunctional monomers, epoxy-based monomers, vinyl ethers, and cyclic ethers. The photopolymerization initiator absorbs light energy to generate radicals or cations, thereby initiating photopolymerization. An appropriate photopolymerization initiator may be selected depending on the photopolymerizable resin.

[0172] For example, when manufacturing smart windows for vehicles, it is preferable to use adhesive layer materials such as PVB (polyvinyl butyral) or EVA (ethylene vinyl acetate), or to coat them with OCR (optically clear resin) and then cure them with UV light for adhesion, and when manufacturing smart windows for building fixtures, it is preferable to use an adhesive layer, but this is not limited to these.

[0173] 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, in order to ensure sufficient adhesive strength and minimize the thickness of the optical laminate, the adhesive layer may have a thickness of 0.1 to 500 μm, preferably 0.5 to 450 μm, and more preferably 1 to 400 μm in the case of an adhesive layer, and may have a thickness of 2 to 30 μm, preferably 3 to 20 μm, and more preferably 5 to 10 μm in the case of an adhesive layer.

[0174] In one embodiment, the adhesive layer 400 may be formed on one or both surfaces of the polarizer by laminating or vacuum bonding.

[0175] The ultraviolet absorbing layer is not particularly limited as long as it is used to prevent deterioration of the optical laminate due to ultraviolet rays, and examples thereof include salicylic acid-based ultraviolet absorbers (phenyl salicylate, p-tert-butyl salicylate, etc.), benzophenone-based ultraviolet absorbers (2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, etc.), benzotriazole-based ultraviolet absorbers (2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-t 2-(2'-hydroxy-3'-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3'-(3'',4'',5'',6''-tetrahydrophthalimidomethyl)-5'-methylphenyl)benzotriazole, 2,2-methylenebis(4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazo 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-(2-octyloxycarbonylethyl)-phenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3'-(1-methyl-1-phenylethyl)-5'-(1,1,3,3-tetramethylbutyl)-phenyl)benzotriazole, 2-(2H-benzotriazol-2-yl)-6-(linear and side chain dodecyl)-4-methylphenol, a mixture of octyl-3-[3-tert-butyl-4-hydroxy-5-(chloro-2H-benzotriazol-2-yl)phenyl]propionate and 2-ethylhexyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazol-2-yl)phenyl]propionate, etc.), cyanoacrylate ultraviolet absorbers (2'-ethylhexyl-2-cyano-3,3-diphenylacrylate, ethyl-2-cyano-3-(3',4'-methylenedioxyphenyl)acrylate, triazine-based UV absorbers, etc. may also be used, and benzotriazole-based UV absorbers or triazine-based UV absorbers, which have high transparency and are excellent in preventing deterioration of polarizing plates and transmittance-variable layers, are preferred, and benzotriazole-based UV absorbers with a more suitable spectral absorption spectrum are particularly preferred. The benzotriazole-based UV absorbers may be bis(bis)-modified, such as 6,6'-methylenebis(2-(2H-benzo[d][1,2,3]triazol-2-yl)-4-(2,4,4-trimethylpentan-2-yl)phenol) or 6,6'-methylenebis(2-(2H-benzo[d][1,2,3]triazol-2-yl)-4-(2-hydroxyethyl)phenol).

[0176] The hard coating layer is not particularly limited as long as it protects components such as a polarizing plate and a transmittance variable layer from external physical and chemical impacts, and any conventional or later developed hard coating layer may be used.

[0177] In one embodiment, the hard coating layer may be formed by applying a composition for forming a hard coating layer to another member and curing the composition with light or heat. The composition for forming a hard coating layer is not particularly limited and may include, for example, a photocurable compound and a photoinitiator.

[0178] The epoxy compound, acrylate-based compound, and photoinitiator may be any compound commonly used in the art, without any particular limitation. For example, the epoxy compound may be a monomer or oligomer having at least one epoxy group in the molecule, the acrylate-based compound may be a monomer or oligomer containing a (meth)acrylate group, and the photoinitiator may be an oxime ester-based compound, etc.

[0179] The present invention includes the method for manufacturing the variable transmittance optical laminate described above. The method for manufacturing the variable transmittance optical laminate is not particularly limited, and the variable transmittance optical laminate can be manufactured using any bonding technique or the above-mentioned photolithography technique.

[0180] <Smart Window> In addition to the variable transmittance optical laminate, the present invention also includes a smart window including the same. The present invention also includes a means of transportation including the smart window, for example, 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, a wearable device including the smart window, and a building fixture.

[0181] For example, a vehicle including the smart window of the present invention may have vehicle glass 500 bonded to both sides of an optical laminate including a polarizer 110, a transparent conductive layer 210, a liquid crystal layer 300, and an adhesive layer 400 (see FIG. 4). For example, the vehicle may be manufactured by placing adhesive films and vehicle glass on both sides of the optical laminate, and then heating the laminate at a temperature of 90°C and about 1 bar or under vacuum for 10 to 20 minutes using a press. Alternatively, the vehicle may be manufactured by coating one side of the vehicle glass with a resin, vacuum bonding the vehicle glass to both sides of the optical laminate, and then UV curing the resin. The adhesive film may include an EVA (ethylene vinyl acetate) film, a PVB (polyvinyl butyral) film, etc., and the resin may have a storage modulus G' of 10 3 ~10 5 It may also contain OCR resin, which is Pa.

[0182] In addition, a building fixture (window glass 600) may be bonded to one surface (see FIG. 5a) or both surfaces (see FIG. 5b) of the optical laminate. Alternatively, a window glass for windows may be bonded to one surface of the optical laminate by lamination to produce a smart window product for windows having the same configuration as that shown in FIG. 5a, or a window glass for windows may be bonded to both surfaces of the optical laminate by applying a UV adhesive and then UV curing to produce a smart window product for windows having the same configuration as that shown in FIG. 5b. [Example]

[0183] 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. The examples are provided only to complete the disclosure of 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.

[0184] Manufacturing example Manufacturing example 1: Manufacturing a polarizing plate (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 for 30 seconds in a swelling bath containing pure water at 20°C. 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.

[0185] (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. In this dyeing treatment, roll-to-roll stretching (longitudinal uniaxial stretching) was also performed with a difference in peripheral speed between the nip rolls. The stretching ratio based on the film after the swelling treatment step was 1.1 times.

[0186] (3) Crosslinking process Next, the film that passed through the nip rolls was immersed for 70 seconds in a first crosslinking bath at 56°C containing pure water / potassium iodide / boric acid (mass ratio) of 100 / 12 / 4. Roll-to-roll stretching (longitudinal uniaxial stretching) was performed with a difference in peripheral speed between the nip rolls and a nip roll prepared between the first and second crosslinking baths. The stretching ratio was 1.9 times, based on the film after the dyeing treatment process.

[0187] (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.

[0188] (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.

[0189] (6) Drying process The washed film was then passed through a drying path 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.

[0190] (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, protective films were laminated on both sides of the polarizer film using the prepared UV adhesive. The resulting laminate was exposed to UV light to harden the adhesive, producing a first polarizing plate and a second polarizing plate. The thickness of the adhesive layer in the resulting polarizing plate was approximately 2 μm.

[0191] Manufacturing example 2: Production of hard coating layer A composition for forming a hard coating layer was prepared by mixing 16.2 g of a dendrimer compound (Miwan Specialty Chemical, SP-1106), inorganic nanoparticles (10 to 20 m, silica particles: 50 wt %, solvent: methyl ethyl ketone (MEK) 14.4 g, 1.8 g of a multifunctional (meth)acrylate containing an ethylene glycol group, 0.7 g of a photoinitiator (1-hydroxycyclohexylphenyl ketone), and 2.9 g of methyl ethyl ketone.

[0192] The obtained composition for forming a hard coating layer was applied to one side of each of the first and second polarizing plates prepared in Preparation Example 1, adjusting the type of Mayer Bar and the solid powder content, and then curing the composition. The hard coating thickness was calculated and the composition was bar-coated. The composition was then dried at 80°C for 5 minutes and then exposed to a high-pressure mercury lamp at 500mJ / cm. 2 The hard coating layer was formed on one surface of each of the first and second polarizing plates.

[0193] Manufacturing example 3: Manufacturing column spacers <Binder resin> A flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping rod and a nitrogen inlet tube was prepared.

[0194] As a monomer dropping lot, 40 parts by weight of a mixture of 3,4-epoxytricyclodecan-8-yl (meth)acrylate and 3,4-epoxytricyclodecan-9-yl (meth)acrylate mixed in a molar ratio of 50:50, 50 parts by weight of methyl methacrylate, 40 parts by weight of acrylic acid, 70 parts by weight of vinyl toluene, 4 parts by weight of t-butyl peroxy-2-ethylhexanoate, and 40 parts by weight of propylene glycol monomethyl ether acetate (PGMEA) were added and stirred.

[0195] A chain transfer agent dropping tank was prepared by adding 6 parts by weight of n-dodecanethiol and 24 parts by weight of PGMEA and stirring. Then, 395 parts by weight of PGMEA was added to the flask, and the atmosphere in the flask was replaced with nitrogen. The flask was then heated to 90°C while stirring. The monomer and chain transfer agent were then added dropwise from the dropping tank. The dropping was carried out over two hours, maintaining the temperature at 90°C. After one hour, the temperature was raised to 110°C and maintained for five hours. This resulted in a binder resin with a solid powder acid value of 100 mg KOH / g and a weight-average molecular weight of 17,000, which did not contain Si-O bonds.

[0196] <Photosensitive resin composition> A photosensitive resin composition was prepared by mixing 12.41 wt% of the obtained binder resin, 0.59 wt% of MA0701 (POSS, Hybrid Plastic Inc.) and 5.32 wt% of dipentaerythritol hexaacrylate (Kayarad DPHA: Nippon Kayaku Co., Ltd.) as photopolymerizable compounds, 1.58 wt% of ethanone-1-[9-ethyl-6-(2-methyl-4-tetrahydropyranyloxybenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime) (Irgacure® OXE-02: Ciba) as a photopolymerization initiator, 0.1 wt% of BYK-052N (BYK) as an additive, and 80 wt% of propylene glycol monomethyl ether acetate (PGMEA) as a solvent.

[0197] <Formation of column spacers> A cured film pattern was formed using the photosensitive resin composition as follows. The resin composition was coated onto the hard coating layer of the first polarizer obtained in Preparation Example 2 using a spin coater, and the height of the coated film was adjusted by adjusting the rotation speed (rpm) to form a resin coating layer. After coating, the film was dried on a hot plate at 80°C for 2 minutes, and then irradiated with active energy rays such as ultraviolet light through a mask (gap 150µm) and a prism at an energy dose of 60mJ / cm, in accordance with the method of Korean Patent Publication No. 10-0990074. 2The resist was exposed to a range of 1000 s and 1000 s. The resist was then developed (development time: 60 seconds) using a developer (0.04% KOH aqueous solution, 25°C). It was then placed in an 80°C convection oven and post-baked for 60 minutes. This resulted in the formation of a cured film pattern having the column spacer height and column spacer tilt angle adjusted to a predetermined angle according to the following example.

[0198] Manufacturing Example 4: Fabrication of transparent conductive layer The second polarizer with the hard coating layer prepared in Preparation Example 2 and the first polarizer with the column spacers prepared in Preparation Example 3 were placed inside the sputtering gun. A 450 W DC power was applied to the sputtering gun, and plasma was induced on the ITO (10 wt% Sn-doped In2O3) target to form a first transparent conductive layer and a second transparent conductive layer with a thickness of 90 nm. The first and second transparent conductive layers were then ion-treated using an ion gun with a 50 W DC power. The fabrication was performed at room temperature under a pressure of 3 mTorr, with argon gas and oxygen gas supplied at 30 sccm and 1 sccm, respectively. The ITO thickness was measured using a FT-SEM, and the ITO sheet resistance (Ω / □) was measured using a four-point probe.

[0199] Manufacturing Example 5: Fabrication of alignment film A TN alignment liquid (RN-4662, Nissan Chemical Industries) was applied to the first and second transparent conductive layers prepared in Preparation Example 4, and the thickness was adjusted using a Mayer Bar, followed by drying (80°C / 2 minutes). Then, UV light was irradiated onto the dried alignment liquid to prepare an alignment film.

[0200] Manufacturing Example 6: Production of optical laminate Using a sealant dispenser (SHOTmini 200Ωx, MUSASHI Co., Ltd.), sealant (UVF-006, 70,000 mPa·s, SEKISUI Co., Ltd.) was applied to the outer periphery of the first transparent conductive layer prepared in Preparation Example 4 using a sharp needle (SPN-0.25-12.7L) at a discharge pressure of 200 mPa according to the product size. Then, with the polarization axes of the first and second polarizers aligned parallel to each other at 0° or 90°, liquid crystal was injected onto the alignment film of the first transparent conductive layer using the ODF (one drop filling) process. Then, the second and first transparent conductive layers were coated with a 3 kg / cm 2 After bonding with pressure, UV curing (500 mJ / cm) was performed along the sealant line. 2 ) was performed to manufacture an optical laminate for smart windows. Then, conductive copper tape (TERAOKA, No. 8323) was adhered to the first transparent conductive layer and the second transparent conductive layer to connect them.

[0201] <Examples and Comparative Examples> Examples 1 to 10 and Comparative Examples 1 to 2: Production of optical laminates Except for the inclination angle of the column spacer, the width and height of the top, the area ratio of the top of the column spacer to the second polarizer, and the alignment film thickness being as shown in Table 1 below, optical laminates of Examples 1 to 10 and Comparative Examples 1 and 2 were manufactured according to Preparation Examples 1 to 6, respectively, and the results of the evaluations performed in the following experiments are shown in Table 1 below.

[0202] Comparative Example 3: Production of optical laminate An optical laminate was prepared in the same manner as in Example 1, except that a first transparent conductive layer and a second transparent conductive layer were formed on the first polarizer and the second polarizer, respectively, on which the hard coating layer prepared in Preparation Example 2 was formed, in the same manner as in Preparation Example 4, and a column spacer was formed on the first transparent conductive layer in the same manner as in Preparation Example 3.

[0203] Then, an alignment film was formed on the second transparent conductive layer and the first transparent conductive layer on which the column spacers were formed in the same manner as in Preparation Example 5, and then an optical laminate was fabricated in the same manner as in Preparation Example 6. At this time, the tilt angle of the column spacers, the width and height of the top, the area ratio of the top of the column spacers to the second polarizer, and the thickness of the alignment film were as shown in Table 1.

[0204] Comparative Example 4: Production of optical laminate An optical laminate was prepared in the same manner as in Example 1, but a first transparent conductive layer and a second transparent conductive layer were formed on the first polarizer and the second polarizer, respectively, on which the hard coating layer prepared in Preparation Example 2 was formed, in the same manner as in Preparation Example 4, and a first alignment film and a second alignment film were formed, respectively, in the same manner as in Preparation Example 5.

[0205] Then, column spacers were formed on the first alignment film in the same manner as in Preparation Example 3, and an optical laminate was fabricated in the same manner as in Preparation Example 6. The tilt angle, upper width, height, area ratio of the upper part of the column spacer to the second polarizer, and thickness of the alignment film were as shown in Table 1.

[0206] [Table 1]

[0207] <Experimental Example> (1) Reliability-driven evaluation Copper tape electrodes were connected to the optical laminates of the examples and comparative examples in a room temperature environment, and then the laminates were subjected to a voltage-on (10 V AC voltage) and voltage-off cycle 200,000 times. The reliability of the drive was evaluated according to the evaluation criteria in Table 2 below, and the results are shown in Table 3 above.

[0208] For reference, when the voltage is ON, the standard for LCD hue front black means that the transmittance is less than 0.5% and the single transmittance hue b* is within the range of -3 to 3, and when the voltage is OFF, the standard for front projection is a transmittance of 20% or more. Also, when visual observation is performed, if black amorphous unevenness defects (see Figure 6), LCD unevenness defects (see Figure 7), light leakage phenomena (see Figure 8), black spots, white spots, etc. are observed, the message "changes observed" is displayed.

[0209] [Table 2]

[0210] ○: All criteria are good, reliability evaluation is normal (200,000 times) △: One of the criteria is not good, reliability drive evaluation is normal (more than 100,000 times but less than 200,000 times) X: All criteria are poor, reliability drive evaluation is poor (less than 100,000 times) (2) Evaluation of optical properties A spectrophotometer (CM-3700d, Konica Minolta) was used to measure the optical laminates of the examples and comparative examples. The second polarizing plate was positioned in the direction of the light source, and the transmittance (%), parallel values, and perpendicular values ​​for the single-layer transmission hue b* value were measured with the voltage applied (voltage ON and voltage OFF). The average values ​​were calculated and shown in Table 3.

[0211] [Table 3]

[0212] Referring to Table 3 above, Examples 1 to 10, which include the column spacer 150 of the present invention, were evaluated as superior in that no defects occurred in the liquid crystal hue or appearance regardless of the voltage application state, compared to Comparative Examples 1 and 2, which have column spacers of a different shape from the column spacer of the present invention, or Comparative Examples 3 and 4, which have a stacking procedure for the optical components that form the laminate that is different from the present invention.

[0213] On the other hand, in Comparative Example 1, where the inclination angle of the column spacer is a right angle, and Comparative Example 2, where the inclination angle is an obtuse angle, the transparent conductive layer could not be deposited on the side of the column spacer, and in the reliability driving evaluation, poor liquid crystal unevenness and afterimages occurred during driving or the liquid crystal did not drive.

[0214] In addition, in the case of Comparative Example 3 in which an alignment film was formed on top of the column spacers, and in the case of Comparative Example 4 in which a column spacer was formed on the alignment film, the column spacers were dissolved by the alignment liquid solvent, and this was visually recognized as black amorphous irregularities from the beginning, and the appearance was observed to be unsatisfactory.

[0215] For reference, Examples 8 and 9 satisfied the range of the present invention in terms of the column spacer specifications and tilt angle, but were outside the preferred alignment film thickness range of 30 to 300 nm, and were observed to be poor in one or more criteria in the reliability evaluation. That is, in Example 8, where the alignment film thickness was less than 30 nm, short circuits occurred between the transparent conductive layers, and black amorphous irregularities were visible. In addition, in Example 9, where the alignment film thickness exceeded 300 nm, the liquid crystal color did not meet the front black standard, liquid crystal irregularities occurred, and afterimages were visible during operation.

[0216] Although Example 10 satisfies the range of the present invention with respect to the column spacer specifications and inclination angle, the inclination angle is outside the preferred range of 70° or less, and similar to Examples 8 and 9, the number of drives in the reliability drive evaluation did not reach 200,000.

[0217] Therefore, it can be seen that the variable transmittance optical laminate of the present invention does not cause liquid crystal defects or current disconnections and is highly reliable. [Industrial Applicability]

[0218] The variable transmittance optical laminate according to the present invention can be made highly reliable when driving the liquid crystal by preventing deformation of the spacers, changes in the performance of the alignment film, and occurrence of liquid crystal defects. [Explanation of symbols]

[0219] 100: First laminate 110: Polarizing plate 110-1: First polarizing plate 110-2: Second polarizing plate 150: Column spacer 200: Second laminate 210: Transparent conductive layer 210-1: First transparent conductive layer 210-2: Second transparent conductive layer 300: Liquid crystal layer 310: Alignment film 310-1: First alignment film 310-2: Second alignment film 350: Liquid crystal compound 400:Adhesive layer 450:Sealant 500: Vehicle glass 600: Building fixtures (glass for fixtures) a: Column spacer inclination angle h: Column spacer height d: Width of the top of the column spacer p: Tangent to the side of the column spacer s: Column spacer side

Claims

1. a first laminate including a first polarizer, one or more column spacers formed on one surface of the first polarizer, a first transparent conductive layer formed on the first polarizer on which the one or more column spacers are formed, and a first alignment film formed on the first transparent conductive layer; a second laminate including a second polarizing plate, a second transparent conductive layer, and a second alignment film laminated in this order opposite to the first laminate; and a liquid crystal layer disposed between the first alignment film and the second alignment film; the column spacer has an inclination angle such that a tangent line of a side of the column spacer forms an acute angle with the first polarizing plate; Variable transmittance optical stack.

2. The variable transmittance optical laminate according to claim 1 , wherein the column spacers have an inclination angle of 70° or less.

3. The variable transmittance optical stack according to claim 1 , wherein the column spacer has a height of 2 to 10 μm and a top width of 4 to 60 μm.

4. The variable transmittance optical laminate of claim 1 , wherein the area of ​​the upper portion of the column spacer is 0.2 to 5.0% of the area of ​​the second polarizer.

5. The variable transmittance optical stack of claim 1 , wherein at least one of the first alignment film and the second alignment film has a thickness of 30 to 300 nm.

6. 2. The variable transmittance optical stack according to claim 1, wherein at least one of the first alignment film and the second alignment film is driven in one or more modes selected from a TN (Twisted Nematic) mode, an STN (Super Twisted Nematic) mode, and a VA (Vertical Alignment) mode.

7. 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.

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

9. the first transparent conductive layer is formed in direct contact with the first polarizer on which the column spacers are formed without using a separate substrate; The variable transmittance optical laminate of claim 1 , wherein the second transparent conductive layer is formed in direct contact with the second polarizer without any additional substrate between the second transparent conductive layer and the second polarizer.

10. the first transparent conductive layer is formed by including an easy-adhesion layer on the first polarizer on which the column spacers are formed, The variable transmittance optical laminate according to claim 1 , wherein the second transparent conductive layer is formed on the second polarizing plate by including an easy-adhesion layer.

11. 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.

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

13. 13. The variable transmittance optical laminate according to claim 12, wherein the adhesive layer is formed using one or more adhesives selected from an acrylic adhesive, a rubber adhesive, a silicone adhesive, a urethane adhesive, a polyvinyl alcohol adhesive, a polyvinylpyrrolidone adhesive, a polyacrylamide adhesive, a cellulose adhesive, a vinyl alkyl ether adhesive; and a photocurable adhesive.

14. A method for producing the variable transmittance optical laminate according to any one of claims 1 to 13.

15. A smart window comprising the variable transmittance optical stack according to any one of claims 1 to 13.

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