KR20240130200A - Transmittance variable optical laminate and manufacturing method for the same, and smart window including the same - Google Patents

Abstract

The present invention relates to a transmittance variable optical laminate comprising: a liquid crystal layer; a first transparent conductive layer formed on one surface of the liquid crystal layer; a second transparent conductive layer formed on the other surface of the liquid crystal layer; a first polarizing plate formed on the first transparent conductive layer; and a second polarizing plate formed on the second transparent conductive layer, wherein at least one polarizing plate among the first and second polarizing plates includes a reflective polarizer and an absorption layer, and the transmission axes of each of the first and second polarizing plates are perpendicular, and a method for manufacturing the same, and a smart window comprising the same.

Description

TRANSMITTANCE VARIABLE OPTICAL LAMINATE AND MANUFACTURING METHOD FOR THE SAME, AND SMART WINDOW INCLUDING THE SAME

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

In general, external light blocking coatings are often applied to the windows of vehicles and other means of transportation. However, the windows of conventional means of transportation have fixed transmittance, and the external light blocking coating also has fixed transmittance. Therefore, the windows of such conventional means of transportation have fixed overall transmittance, which may cause accidents. For example, if the overall transmittance is set low, there is no problem during the day when there is sufficient surrounding light, but at night when there is not enough surrounding light, there is a problem that drivers and others may have difficulty properly checking the surroundings of the means of transportation. Or, if the overall transmittance is set high, there is a problem that drivers and others may be dazzled during the day when there is sufficient surrounding light. In addition, external light blocking coatings are often applied to the windows of buildings and other means of transportation to improve the efficiency of heating and cooling and to save energy. In this case, if the transmittance is fixed, there is a problem that it is not efficient in saving energy, as in the case of means of transportation.

Accordingly, a transmittance-variable optical laminate capable of changing the transmittance of light when voltage is applied has been developed. The transmittance-variable optical laminate is driven by driving liquid crystals according to the application of voltage to change the transmittance, and the desired transmittance is achieved by providing a liquid crystal layer whose phase changes according to the application of an electric field for changing the transmittance.

Japanese Patent Publication No. 2018-010035 discloses a transmittance variable optical laminate including a transparent electrode layer formed on a polycarbonate (PC) substrate having a predetermined thickness, but in this case, since the product size is limited to the width of a polarizing plate original, there is a limit to providing a large-area laminate.

Therefore, there is a need to develop a transmittance variable optical laminate that can provide a large area while lowering reflectivity without compromising transmittance.

Japanese Publication Patent No. 2018-010035

In order to solve the above-described problems, the present invention seeks to provide a large-area, variable transmittance optical laminate applicable to buildings.

In addition, the present invention seeks to provide a smart window including the above-described variable transmittance optical laminate and a window for an automobile or building to which the same is applied.

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

The present invention relates to a transmittance variable optical laminate comprising: a liquid crystal layer; a first transparent conductive layer formed on one surface of the liquid crystal layer; a second transparent conductive layer formed on the other surface of the liquid crystal layer; a first polarizing plate formed on the first transparent conductive layer; and a second polarizing plate formed on the second transparent conductive layer, wherein at least one of the first polarizing plate and the second polarizing plate includes a reflective polarizer and an absorption layer, and transmission axes of each of the first polarizing plate and the second polarizing plate are perpendicular.

In the present invention, the first polarizing plate and the second polarizing plate may have machine directions (MDs) that are parallel to each other.

In the present invention, the optical laminate with variable transmittance may be manufactured by a roll-to-roll continuous process.

The present invention may be such that at least one of the first polarizing plate and the second polarizing plate includes a stretchable polarizer.

The present invention may have a reflectivity of 15% or less.

In the present invention, at least one polarizing plate among the first polarizing plate and the second polarizing plate may include at least one functional layer selected from the group consisting of a functional coating layer, a protective layer, a phase difference control layer, and a refractive index control layer.

In 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.

In the present invention, at least one of the first transparent conductive layer and the second transparent conductive layer may be formed in direct contact with one of the first polarizing plate and the second polarizing plate without including a separate substrate therebetween.

The present invention may be formed by direct contact between at least one of the first transparent conductive layer and the second transparent conductive layer and one of the first and second polarizing plates, such that the transparent conductive layer further includes an adhesive-friendly layer between the first and second polarizing plates.

In the present invention, at least one of the first transparent conductive layer and the second transparent conductive layer may include at least one selected from the group consisting of transparent conductive oxides, metals, carbon-based materials, conductive polymers, conductive inks, and nanowires.

In the present invention, the liquid crystal layer may be driven in a TN (Twisted Nematic) mode.

In the present invention, the liquid crystal layer may include at least one spacer selected from the group consisting of a ball spacer and a column spacer.

The present invention may further include at least one selected from the group consisting of a sealant, an alignment film, a point-based adhesive layer, and an ultraviolet absorbing layer, wherein the variable transmittance optical laminated body.

The present invention also relates to a method for manufacturing the above-mentioned variable transmittance optical laminate.

In addition, the present invention may be characterized in that the method for manufacturing the above-mentioned variable transmittance optical laminate is a roll-to-roll continuous process.

The present invention also relates to a smart window including the above-described variable transmittance optical laminate.

In addition, the present invention may relate to a means of transportation including the smart window, and may relate to an automobile in which the smart window is applied to at least one of a front window, a rear window, a side window, a sunroof window, and an interior partition.

In addition, the present invention may relate to a wearable device including the smart window and an architectural window.

According to the optical layer having variable transmittance according to the present invention, the transmittance of visible light can be adjusted according to the application of voltage.

In addition, according to the variable transmittance optical laminate of the present invention, the reflectance can be reduced while maintaining the transmittance.

In addition, according to the variable transmittance optical laminate according to the present invention, a large-area variable transmittance optical laminate applicable to buildings can be provided.

FIG. 1 is a diagram schematically illustrating a laminated structure of a variable transmittance optical laminate according to an embodiment of the present invention.
FIG. 2 is a diagram for explaining the laminated structure of a variable transmittance optical laminate according to one embodiment of the present invention.

The present invention relates to a transmittance variable optical laminate which can be manufactured by a roll-to-roll continuous process and thus can be provided over a large area, and which can control transmittance and lower reflectance according to application of voltage, and a method for manufacturing the same, and a smart window including the same. More specifically, the transmittance variable optical laminate includes a liquid crystal layer; a first transparent conductive layer formed on one surface of the liquid crystal layer; a second transparent conductive layer formed on the other surface of the liquid crystal layer; a first polarizing plate formed on the first transparent conductive layer; and a second polarizing plate formed on the second transparent conductive layer, wherein at least one of the first polarizing plate and the second polarizing plate includes a reflective polarizer and an absorption layer, and the transmission axes of each of the first polarizing plate and the second polarizing plate may be perpendicular and their respective machine directions (MDs) may be parallel to each other.

The optical laminate with variable transmittance of the present invention is particularly suitable for a technical field in which the transmittance of light can be changed according to the application of voltage, and can be used, for example, in smart windows.

A smart window is an optical structure that controls the amount of light or heat that passes through by changing the light transmittance according to the application of an electrical signal. In other words, a smart window is provided so that it can be changed to a transparent, opaque, or translucent state by voltage, and is also called variable transmittance glass, dimming glass, or smart glass.

Smart windows can be used as partitions for dividing the interior space of vehicles and buildings or for privacy, or as skylights placed in openings of buildings, and can also be used as highway signs, bulletin boards, scoreboards, clocks or advertising screens, and can be used to replace glass in transportation means such as windows or sunroofs of cars, buses, airplanes, ships or trains.

The optical laminate with variable transmittance of the present invention can also be utilized as a smart window in the various technical fields described above, but since the conductive layer is formed directly on the polarizing plate, it does not include a separate substrate for forming the conductive layer, so it is thin and has advantageous bending characteristics, and can be particularly suitably used as a smart window for vehicles or buildings. In one or more embodiments, the smart window to which the optical laminate with variable transmittance of the present invention is applied can be used for front windows, rear windows, side windows, and sunroof windows of vehicles, or windows for buildings, and in addition to the purpose of blocking external light, it can also be used for partitioning internal spaces of vehicles or buildings, such as interior partitions, or for protecting privacy.

Hereinafter, with reference to the drawings, embodiments of the present invention will be described in more detail. However, the following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the contents of the invention described above, serve to further understand the technical idea of the present invention, so the present invention should not be interpreted as being limited to matters described in such drawings.

The terms used herein are for the purpose of describing embodiments and are not intended to limit the present invention. In this specification, the singular also includes the plural unless specifically stated in the phrase. For example, as used herein, "polarizing plate" may mean at least one polarizing plate among the first polarizing plate and the second polarizing plate, and "transparent conductive layer" may mean at least one transparent conductive layer among the first transparent conductive layer and the second transparent conductive layer.

As used herein, the terms “comprises” and/or “comprising” are used to mean that they do not exclude the presence or addition of one or more other components, steps, operations, and/or elements other than the components, steps, operations, and/or elements mentioned. Like reference numerals refer to like elements throughout the specification.

Spatially relative terms such as "below," "bottom," "lower," "above," "top," and "upper" can be used to easily describe the relationship between one element or component and other elements or components, as illustrated in the drawings. It should be understood that spatially relative terms include different orientations of the elements during use or operation in addition to the orientations illustrated in the drawings. For example, if an element illustrated in the drawings is flipped, an element described as "below" or "lower" of another element can be placed "above" the other element. Thus, the exemplary term "below" can include both the above and below directions. The elements can also be oriented in other directions, and thus spatially relative terms can be interpreted according to the orientation.

As used herein, “plane direction” can be interpreted as a direction orthogonal to the polarizing plate and/or transparent conductive layer, i.e., the direction viewed from the user’s viewing side.

As used herein, “substantially” may be interpreted to include not only physically identical or identical, but also within a range of error in the measurement or manufacturing process, for example, it may be interpreted to mean a range of error of 0.1% or less.

<Variable Transmittance Optical Laminate>

FIG. 1 is a diagram schematically illustrating a laminated structure of a transmittance variable optical laminate according to an embodiment of the present invention, and FIG. 2 is a diagram for explaining the laminated structure of a transmittance variable optical laminate according to an embodiment of the present invention.

Referring to FIGS. 1 and 2, a variable transmittance optical laminate according to an embodiment of the present invention may include a liquid crystal layer (130) formed between a first polarizing plate (110) and a second polarizing plate (120), and at least one of the first polarizing plate (110) and the second polarizing plate (120) may include a reflective polarizer (120-2) and an absorption layer (140). The transmission axes of the first polarizing plate (110) and the second polarizing plate (120) are perpendicular to each other, and the mechanical directions (MDs) are parallel to each other, so that the production of a maximum-sized optical laminate is possible. The term “mechanical direction (MD)” used herein means the direction in which each polarizing plate is conveyed in a roll-to-roll continuous process, that is, the mechanical flow direction. Therefore, when the machine directions (MD) of the first polarizing plate (110) and the second polarizing plate (120) are arranged parallel to each other in the plane direction, a roll-to-roll continuous process can be applied when manufacturing a variable transmittance optical laminate including the same, so that the process is continuous and economical, making manufacturing easy. In addition, since there is no need to transport the optical laminate separately, handling problems such as folding or damage do not occur even when manufacturing a large-area optical laminate, so that a large-area variable transmittance optical laminate can also be manufactured.

In addition, although the polarizing plate including the reflective polarizer (120-2) and the light absorption layer (140) positioned downward with respect to the liquid crystal layer (130) in this specification is described as the second polarizing plate (120), the first polarizing plate (110) and the second polarizing plate (120) may have different up-down directions depending on convenience.

In addition, according to one embodiment of the present invention, at least one of the first polarizing plate (110) and the second polarizing plate (120) may include a reflective polarizer (120-1) and an absorption layer (140). More specifically, referring to FIG. 1, for example, the first polarizing plate (110) may include a stretchable polarizer (110-1), and the second polarizing plate (120) may include a reflective polarizer (120-1), and may include an absorption layer (140) at the outermost side opposite to the liquid crystal layer (130) based on the reflective polarizer. The “outermost side” is not limited to the viewing direction. It is more preferable in terms of manufacturing an optical laminate including a liquid crystal layer to which a TN (Twisted Nematic) mode is applied by adjusting the machine direction (MD) to be parallel and the transmission axis to be vertical.

In one embodiment, the reflective polarizer is not particularly limited as long as it can improve the transmittance variable range between the light-transmitting mode and the light-shielding mode of the optical laminate, and a reflective polarizer developed in the related art or later can be used, and in some embodiments, the reflective polarizer can include a pattern portion formed on at least one surface.

In one embodiment, the reflective polarizer may have a form of a laminate in which a plurality of first layers and second layers are alternately laminated. The x-axis refractive index (n ₁ x) of the first layer is different from the y-axis refractive index (n ₁ y), and the y-axis refractive index (n ₁ y) of the first layer is formed to be substantially equal to the y-axis refractive index (n ₂ y) of the second layer.

Accordingly, among the light incident on the reflective polarizer, light having a linear polarization component in the y-axis direction is transmitted through the reflective polarizer and emitted as light having a linear polarization component in the y-axis direction. At this time, the direction in which the emitted light transmits (y-axis direction) is called the transmission axis.

The first layer and the second layer of the above-mentioned reflective polarizer may use those developed in the past or later as long as they do not harm the purpose of the present invention. For example, the first layer may use stretched polyethylene naphthalate (PEN), and the second layer may use copolyester of naphthalene dicarboxylic acid and terephthalic or isothalic acid (coPEN).

In another embodiment of the present invention, the polarizing plate (110 of FIGS. 1 and 2) of the other side of the first polarizing plate and the second polarizing plate that does not include the reflective polarizer and the absorbing layer may include a stretchable polarizer or a coated polarizer, and the material is not limited as long as the transmission axes of the first polarizing plate (110) and the second polarizing plate (120) are perpendicular to each other and the machine directions (MDs) can be parallel to each other, but it is more preferable to include a stretchable polarizer in order to increase the size of the optical laminate.

The above-mentioned stretchable polarizer may include an extended polyvinyl alcohol (PVA) resin. The polyvinyl alcohol (PVA) resin may be a polyvinyl alcohol resin obtained by saponifying a polyvinyl acetate resin. As the polyvinyl acetate resin, in addition to polyvinyl acetate, which is a homopolymer of vinyl acetate, a copolymer of vinyl acetate and another monomer copolymerizable therewith may be mentioned. The other monomer may be an unsaturated carboxylic acid monomer, an unsaturated sulfonic acid monomer, an olefin monomer, a vinyl ether monomer, an acrylamide monomer having an ammonium group, or the like. In addition, the polyvinyl alcohol (PVA) resin may include a modified one, and may be, for example, polyvinyl formal or polyvinyl acetal modified with aldehydes.

In one embodiment, the coated polarizer can be formed by a liquid crystal coating composition, wherein the liquid crystal coating composition can include a reactive liquid crystal compound and a dichroic dye, etc.

The above reactive liquid crystal compound may refer to a compound including, for example, a mesogen skeleton and also including one or more polymerizable functional groups. Such reactive liquid crystal compounds are known in various ways under the name of so-called RM (Reactive Mesogen). The above reactive liquid crystal compound can form a cured film in which a polymer network is formed while maintaining the liquid crystal arrangement by polymerization by light or heat.

The above reactive liquid crystal compound may be a monofunctional or polyfunctional reactive liquid crystal compound. The monofunctional reactive liquid crystal compound may refer to a compound having one polymerizable functional group, and the polyfunctional reactive liquid crystal compound may refer to a compound having two or more polymerizable functional groups.

The above-mentioned dichroic dye is a component that is included in a liquid crystal coating composition and provides polarization properties, and has different absorbances in the long axis direction and the short axis direction of the molecule. The above dichroic dye may be a dichroic dye that has been developed previously or will be developed later, and may include, for example, at least one selected from the group consisting of azo dyes, anthraquinone dyes, perylene dyes, merocyanine dyes, azomethine dyes, phthaloperylene dyes, indigo dyes, dioxadine dyes, polythiophene dyes, and phenoxazine dyes.

The liquid crystal coating composition may further include a solvent capable of dissolving the reactive liquid crystal compound and the dichroic dye, and examples thereof include propylene glycol monomethyl ether acetate (PGMEA), methyl ethyl ketone (MEK), xylene, and chloroform. In addition, the liquid crystal coating composition may further include a leveling agent, a polymerization initiator, and the like, within a range that does not impair the polarization characteristics of the coating film.

The above-described light absorption layer (140) is included in at least one of the first polarizing plate and the second polarizing plate, and may be included in the second polarizing plate (120) including a reflective polarizer, for example, referring to FIGS. 1 and 2. Specifically, since the reflective polarizer has both a transmission function and a reflection function, if only the reflective polarizer is applied, the reflectivity may be very high. However, according to one embodiment of the present invention, by further including a light absorption layer as a functional layer on the outermost surface of the reflective polarizer, the reflectivity may be lowered to 15% or less while maintaining the transmittance, thereby providing a transmittance variable optical laminate having excellent optical characteristics and visibility.

The light absorption layer (140) is preferably used in the form of a hard coating layer composition that has been developed or applied in the related art and includes a dye to reduce the reflectance of the optical laminate to 15% or less. The hard coating layer composition may be formed from a hard coating composition that includes an acrylate-based or epoxy-based compound, inorganic fine particles, a photoinitiator, and the like. The acrylate-based compound may include a monomer or oligomer that includes a (meth)acrylate group, and the term "(meth)acryl-" used herein is used to mean "methacryl-", "acryl-", or both. Non-limiting examples of the above acrylate compounds include neopentyl glycol acrylate, 1,6-hexanediol (meth)acrylate, propylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, 1,2,4-cyclohexane tetra(meth)acrylate, pentaglycerol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate. Examples thereof include dipentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol tri(meth)acrylate, tripentaerythritol hexatri(meth)acrylate, bis(2-hydroxyethyl)isocyanurate di(meth)acrylate, hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, hydroxybutyl(meth)acrylate, isooctyl(meth)acrylate, iso-dexyl(meth)acrylate, stearyl(meth)acrylate, tetrahydrofurfuryl(meth)acrylate, phenoxyethyl(meth)acrylate, and isoborneol(meth)acrylate. These may be used alone or in combination of two or more. The above acrylate compound may include an epoxy (meth)acrylate compound and/or a urethane (meth)acrylate compound. In addition, the epoxy compound may include a monomer or oligomer having at least one epoxy group in a molecule. The epoxy group may be an alicyclic epoxy group. The alicyclic ring included in the epoxy group may have 3 to 7 carbon atoms, and may be, for example, an alicyclic epoxy group (cyclohexylepoxy) including a cyclohexane ring. The alicyclic ring may have a substituent. For example, the alicyclic ring may include an alkyl substituent having 1 to 20 carbon atoms. When the alkyl substituent has more than 20 carbon atoms, it may be disadvantageous in terms of the curing speed. The alkyl substituent may be linear or branched, and in the case of a branched type, the number of carbon atoms may be 3 or more.

The dye included in the composition for forming the light-absorbing layer may be used without limitation as long as it has solubility in an organic solvent. It is preferable to use a dye that has solubility in an organic solvent and can secure reliability such as solubility in an alkaline developer, heat resistance, and solvent resistance.

As the dyes mentioned above, those selected from acid dyes having acid groups such as sulfonic acid or carboxylic acid, salts of acid dyes and nitrogen-containing compounds, sulfonamide-based acid dyes, and derivatives thereof can be used. In addition, azo-based, xanthene-based, phthalocyanine-based acid dyes and derivatives thereof can also be selected.

Preferably, the dye is a compound classified as a dye in the Color Index (published by The Society of Dyers and Colourists) or a known dye described in the dyeing notes (color dyes).

Specific examples of the above dyes include C.I. solvent dyes,

Yellow dyes such as C.I. Solvent Yellow 4, 14, 15, 16, 21, 23, 24, 38, 56, 62, 63, 68, 79, 82, 93, 94, 98, 99, 151, 162, 163;

Red dyes such as C.I. Solvent Red 8, 45, 49, 89, 111, 122, 125, 130, 132, 146, 179;

Orange dyes such as C.I. Solvent Orange 2, 7, 11, 15, 26, 41, 45, 56, 62;

Blue dyes such as C.I. Solvent Blue 5, 35, 36, 37, 44, 59, 67, 70;

Violet dyes such as C.I. Solvent Violet 8, 9, 13, 14, 36, 37, 47, 49;

Examples include green dyes such as C.I. Solvent Green 1, 3, 4, 5, 7, 28, 29, 32, 33, 34, and 35.

Among them, C.I. solvent dyes having excellent solubility in organic solvents, C.I. solvent yellow 14, 16, 21, 56, 151, 79, 93; C.I. solvent red 8, 49, 89, 111, 122, 132, 146, 179; C.I. solvent orange 41, 45, 62; C.I. solvent blue 35, 36, 44, 45, 70; C.I. solvent violet 13 are preferable, and among them, C.I. solvent yellow 21, 79; C.I. solvent red 8, 122, 132; C.I. solvent orange 45, 62 are more preferable.

Also, as a C.I. acid dye,

C.I. Acid Yellow 1, 3, 7, 9, 11, 17, 23, 25, 29, 34, 36, 38, 40, 42, 54, 65, 72, 73, 76, 79, 98, 99, 111, 112, 113, 114, 116, 119, 123, 128, 134, 135, 138, 139, 140, 144, 150, 155, 157, 160, 161, 163, 168, 169, 172, 177, 178, 179, 184, 190, 193, 196, Yellow dyes such as 197, 199, 202, 203, 204, 205, 207, 212, 214, 220, 221, 228, 230, 232, 235, 238, 240, 242, 243, 251;

C.I. Acid Red 1, 4, 8, 14, 17, 18, 26, 27, 29, 31, 34, 35, 37, 42, 44, 50, 51, 52, 57, 66, 73, 80, 87, 88, 91, 92, 94, 97, 103, 111, 114, 129, 133, 134, 138, 143, 145, 150, 151, 158, 176, 182, 183, 198, 206, 211, 215, 216, 217, 227, 228, 249, 252, Red dyes such as 257, 258, 260, 261, 266, 268, 270, 274, 277, 280, 281, 195, 308, 312, 315, 316, 339, 341, 345, 346, 349, 382, 383, 394, 401, 412, 417, 418, 422, 426;

Orange dyes such as C.I. Acid Orange 6, 7, 8, 10, 12, 26, 50, 51, 52, 56, 62, 63, 64, 74, 75, 94, 95, 107, 108, 169, 173;

Blue dyes such as C.I. Acid Blue 1, 7, 9, 15, 18, 23, 25, 27, 29, 40, 42, 45, 51, 62, 70, 74, 80, 83, 86, 87, 90, 92, 96, 103, 112, 113, 120, 129, 138, 147, 150, 158, 171, 182, 192, 210, 242, 243, 256, 259, 267, 278, 280, 285, 290, 296, 315, 324:1, 335, 340;

Violet dyes such as C.I. Acid Violet 6B, 7, 9, 17, 19, 66;

Examples include green dyes such as C.I. Acid Green 1, 3, 5, 9, 16, 25, 27, 50, 58, 63, 65, 80, 104, 105, 106, and 109.

Among these, C.I. Acid Yellow 42; C.I. Acid Red 52, 92; C.I. Acid Blue 80, 90; C.I. Acid Violet 66; and C.I. Acid Green 27, which have excellent solubility in organic solvents among acid dyes, are preferable.

Also as a C.I. direct dye,

Yellow dyes such as C.I. Direct Yellow 2, 33, 34, 35, 38, 39, 43, 47, 50, 54, 58, 68, 69, 70, 71, 86, 93, 94, 95, 98, 102, 108, 109, 129, 136, 138, 141;

Red dyes such as C.I. Direct Red 79, 82, 83, 84, 91, 92, 96, 97, 98, 99, 105, 106, 107, 172, 173, 176, 177, 179, 181, 182, 184, 204, 207, 211, 213, 218, 220, 221, 222, 232, 233, 234, 241, 243, 246, 250;

Orange dyes such as C.I. Direct Orange 34, 39, 41, 46, 50, 52, 56, 57, 61, 64, 65, 68, 70, 96, 97, 106, 107;

C.I. Direct Blue 38, 44, 57, 70, 77, 80, 81, 84, 85, 86, 90, 93, 94, 95, 97, 98, 99, 100, 101, 106, 107, 108, 109, 113, 114, 115, 117, 119, 137, 149, 150, 153, 155, 156, 158, 159, 160, 161, 162, 163, 164, 166, 167, 170, 171, 172, 173, 188, 189, 190, Blue dyes such as 192, 193, 194, 196, 198, 199, 200, 207, 209, 210, 212, 213, 214, 222, 228, 229, 237, 238, 242, 243, 244, 245, 247, 248, 250, 251, 252, 256, 257, 259, 260, 268, 274, 275, 293;

Violet dyes such as C.I. Direct Violet 47, 52, 54, 59, 60, 65, 66, 79, 80, 81, 82, 84, 89, 90, 93, 95, 96, 103, 104;

Examples include green dyes such as C.I. Direct Green 25, 27, 31, 32, 34, 37, 63, 65, 66, 67, 68, 69, 72, 77, 79, and 82.

Also, as a C.I. modanto dye,

Yellow dyes such as C.I. Modanto Yellow 5, 8, 10, 16, 20, 26, 30, 31, 33, 42, 43, 45, 56, 61, 62, 65;

Red dyes such as C.I. Modanto Red 1, 2, 3, 4, 9, 11, 12, 14, 17, 18, 19, 22, 23, 24, 25, 26, 30, 32, 33, 36, 37, 38, 39, 41, 43, 45, 46, 48, 53, 56, 63, 71, 74, 85, 86, 88, 90, 94, 95;

Orange dyes such as C.I. Modanto Orange 3, 4, 5, 8, 12, 13, 14, 20, 21, 23, 24, 28, 29, 32, 34, 35, 36, 37, 42, 43, 47, 48;

Blue dyes such as C.I. Modanto Blue 1, 2, 3, 7, 8, 9, 12, 13, 15, 16, 19, 20, 21, 22, 23, 24, 26, 30, 31, 32, 39, 40, 41, 43, 44, 48, 49, 53, 61, 74, 77, 83, 84;

Violet dyes such as C.I. Modanto Violet 1, 2, 4, 5, 7, 14, 22, 24, 30, 31, 32, 37, 40, 41, 44, 45, 47, 48, 53, 58;

Examples of green dyes include C.I. Modanto Green 1, 3, 4, 5, 10, 15, 19, 26, 29, 33, 34, 35, 41, 43, and 53.

In the present invention, the dyes may be used singly or in combination of two or more.

In the method for manufacturing the light-absorbing layer (140), the composition for forming the light-absorbing layer may further include inorganic fine particles. The inorganic fine particles may be inorganic fine particles having a particle size of nanoscale, for example, nano-fine particles having a particle size of 100 nm or less, preferably 10 to 100 nm, more preferably 10 to 50 nm. In addition, the inorganic fine particles may be silica fine particles, aluminum oxide particles, titanium oxide particles, zinc oxide particles, or the like.

By including the above-mentioned inorganic fine particles, the hardness of the light-absorbing layer can be further improved. The above-mentioned inorganic fine particles can be included in an amount of 10 to 60 parts by weight, preferably 20 to 50 parts by weight, based on 100 parts by weight of the composition for forming the light-absorbing layer, but is not limited thereto.

According to one embodiment of the present invention, in a method for manufacturing an absorbing layer, the composition for forming the absorbing layer includes a photoinitiator. According to one embodiment of the present invention, the photoinitiator may include, but is not limited to, 1-hydroxy-cyclohexyl-phenylketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1-propanone, methylbenzoyl formate, α,α-dimethoxy-α-phenylacetophenone, 2-benzoyl-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanonediphenyl(2,4,6-trimethylbenzoyl)-phosphine oxide or bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide. Also, products currently on the market include Irgacure 184, Irgacure 500, Irgacure 651, Irgacure 369, Irgacure 907, Darocur 1173, Darocur MBF, Irgacure 819, Darocur TPO, Irgacure 907, Esacure KIP 100F, etc. These photoinitiators can be used alone or in combination of two or more different types.

According to one embodiment of the present invention, the photoinitiator may be included in an amount of 0.5 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the composition for forming the light-absorbing layer. When the photoinitiator is present in the above range, sufficient crosslinking photopolymerization can be achieved without deteriorating the physical properties of the light-absorbing layer.

Meanwhile, in the method for manufacturing an absorbing layer of the present invention, the composition for forming the absorbing layer may additionally contain, in addition to the above-described components, additives commonly used in the technical field to which the present invention belongs, such as a surfactant, an anti-yellowing agent, a leveling agent, or an antifouling agent. In addition, the content thereof may be variously adjusted within a range that does not deteriorate the physical properties of the composition for forming the absorbing layer according to the present invention, and therefore is not particularly limited.

In one or more embodiments, at least one of the first polarizing plate and the second polarizing plate may further include one or more functional layers selected from the group consisting of a functional coating layer, a protective layer, a phase difference control layer, and a refractive index control layer.

The above functional coating layer is provided to improve the hardness of the polarizing plate, and is not particularly limited as long as it can improve the hardness of the polarizing plate, and may include, for example, a hard coating layer and/or a low refractive index layer.

Since the above hard coating layer can be applied as is, excluding the dye from the functional layer (140) composition described above, description thereof is omitted.

The low refractive index layer may be provided to also perform the function of improving the hardness of the polarizing plate within a range that does not harm the purpose of the present invention. The low refractive index layer may include one or more low refractive index agents selected from the group consisting of, for example, SiO ₂ , Al ₂ O ₃ , MgF ₂ , CaF , and cryloite, and in some embodiments, may include a compound used in the hard coating layer, a resin commonly used in the technical field to which the present invention belongs, and the like. The hard coating layer and the low refractive index layer may each be used alone, and in some embodiments, may be used in a multi-layer structure.

The functional coating layer may be formed by directly contacting one surface of the polarizer, but is not limited thereto. For example, when the polarizing plate includes a phase difference control layer and/or a refractive index control layer, the functional coating layer may be formed on one surface of the phase difference control layer and the refractive index control layer, so that the functional coating layer, the phase difference control layer, the refractive index control layer, and the polarizer are sequentially laminated.

The functional coating layer is preferably formed on the liquid crystal layer side of the polarizer, that is, on the inner side of the polarizer, but is not limited thereto, and may also be formed on the outer side of the polarizer so that the polarizer, the functional coating layer, and the protective layer are sequentially laminated. In this case, the functional coating layer has an advantage in that cracks or scratches occurring during the manufacturing or processing process of the optical laminate can be minimized by imparting a level of hardness suitable for forming a transparent conductive layer or other member on the polarizing plate.

The above functional coating layer may not only have excellent wear resistance, but may also further improve the bending resistance and durability of the optical laminate, and more specifically, may more effectively suppress the occurrence of defects such as cracks in the conductive layer due to pressure applied by a spacer in the bonding process of the optical laminate or chemical reactions of liquid crystals, alignment films, etc.

In one or more embodiments, the thickness of the functional coating layer after drying may be, but is not limited to, 1 to 50 μm, more preferably 1 to 40 μm.

The above protective layer is intended to preserve the polarization characteristics of the polarizer from post-processing and external environments, and can be implemented in the form of a protective film or the like.

The above protective layer may be formed by direct contact on one or both sides of the polarizer, but is not limited thereto. For example, the protective layer may be used as a multilayer structure in which one or more protective layers are continuously laminated, and may be formed by direct contact on another member such as a phase difference adjustment layer.

In one or more embodiments, the protective layer may include at least one 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). there is.

Additionally, the protective layer may further include an ultraviolet absorber on the outermost surface to prevent deterioration of the function of the optical laminate. The above UV absorbent is not particularly limited as long as it is for preventing deterioration of the optical laminate due to UV rays, and examples thereof include salicylic acid-based UV absorbents (phenyl salicylate, p-tert-butyl salicylate, etc.), benzophenone-based UV absorbents (2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, etc.), benzotriazole-based UV absorbents (2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-Hydroxy-3'-(3",4",5",6"-tetrahydrophthalimidemethyl)-5'-methylphenyl)benzotriazole, 2,2-Methylenebis(4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol), 2-(2'-Hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-Hydroxy-3'-tert-butyl5'-(2-octyloxycarbonylethyl)-phenyl)-5-chlorobenzotriazole, 2-(2'-Hydroxy-3'-(1-methyl-1-phenylethyl)-5'-(1,1,3,3-tetramethylbutyl)-phenyl)benzotriazole, 2-(2H-benzotriazol-2-yl)-6-(linear and branched dodecyl)-4-methylphenol, octyl-3-[3-tert-butyl-4-hydroxy-5-(chloro-2H-benzotriazol-2-yl)phenyl]propionate, mixtures of 2-ethylhexyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazol-2-yl)phenyl]propionate, etc.), cyanoacrylate-based ultraviolet absorbers (2'-ethylhexyl-2-cyano-3,3-diphenylacrylate, ethyl-2-cyano-3-(3',4'-methylenedioxyphenyl)-acrylate, etc.), triazine-based ultraviolet absorbers, etc., can be used, and benzotriazole-based ultraviolet absorbers or triazine-based ultraviolet absorbers with high transparency and excellent effect in preventing deterioration of substrates such as polarizing plates can be used. An absorbent is preferable, and a benzotriazole-based UV absorbent having a more appropriate spectral absorption spectrum is particularly preferable. The benzotriazole-based UV absorbent may be a bis-based one, and examples thereof include 6,6'-methylenebis(2-(2H-benzo[d][1,2,3]triazol-2-yl)-4-(2,4,4-trimethylpentan-2-yl)phenol), 6,6'-methylenebis(2-(2H-benzo[d][1,2,3]triazol-2-yl)-4-(2-hydroxyethyl)phenol), etc.

The above protective layer is intended to protect the polarization characteristics of the polarizing plate from post-processing and external environments, and may be implemented in the form of a protective film, etc. The above protective layer may also be used as a multi-layer structure in which one or more protective layers are continuously laminated, and may also be used in combination with other functional layers.

In one or more embodiments, the protective layer may include at least one 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). there is.

The above-mentioned phase difference control layer is intended to complement the optical characteristics of the optical laminate, and can be implemented in the form of a phase difference film, etc., and can use a phase difference film, etc. that is conventional or developed in the future. For example, a quarter-wave plate (1/4 wave plate) or a half-wave plate (1/2 wave plate) for delaying the phase of light can be used, and these can be used alone or in combination.

The above phase difference control layer may be formed by directly contacting one surface of the polarizer, but is not limited thereto. For example, the phase difference control layer may be formed by directly contacting one surface of the protective layer, or may be formed by directly contacting one surface of the refractive index control layer.

The above-mentioned phase difference control layer can use a polymer film or a liquid crystal polymer film that is stretched in an appropriate manner to impart optical anisotropy through stretching.

In one embodiment, the polymer stretched film may use a polymer layer including a polyolefin such as polyethylene (PE) or polypropylene (PP), a cyclo olefin polymer (COP) such as polynorbornene, a polyester such as polyvinyl chloride (PVC), polyacrylonitrile (PAN), polysulfone (PSU), an acrylic resin, polycarbonate (PC), or polyethylene terephthalate (PET), a cellulose ester polymer such as polyacrylate, polyvinyl alcohol (PVA), or triacetyl cellulose (TAC), or a copolymer of two or more monomers among the monomers forming the polymer.

The method for obtaining the above polymer stretched film is not particularly limited, and for example, the polymer material can be formed into a film and then stretched. The method for forming into the film form is not particularly limited, and it is possible to form the film by known methods such as injection molding, sheet molding, blow molding, injection blow molding, inflation molding, extrusion molding, foam molding, and cast molding, and secondary processing molding methods such as pressure molding and vacuum molding can also be used. Among these, extrusion molding and cast molding are preferably used. At this time, for example, an extruder equipped with a T die, a circular die, etc. can be used to extrusion mold an unstretched film. When obtaining a molded product by extrusion molding, a material in which various resin components, additives, etc. are melt-mixed in advance can be used, and it can also be molded by melt-mixing during extrusion molding. In addition, a solvent common to various resin components, such as chloroform or dimethylene chloride, can be used to dissolve various resin components, and then cast and dry and solidify to cast an unstretched film.

The above polymer stretched film can be stretched uniaxially in the mechanical direction (MD; mechanical direction, longitudinal direction or length direction) of the formed film, uniaxially in the direction perpendicular to the mechanical direction (TD; transverse direction, transverse direction or width direction), and can also be manufactured into a biaxially stretched film by stretching by a sequential biaxial stretching method of roll stretching and tenter stretching, a simultaneous biaxial stretching method by tenter stretching, a biaxial stretching method by tubular stretching, etc.

The above liquid crystal polymerization film may contain a reactive liquid crystal compound in a polymerized state. The reactive liquid crystal compound may be applied in the same manner as the reactive liquid crystal compound of the above-described coated polarizer.

In one or more embodiments, the thickness of the phase difference control layer may be 10 to 100 ㎛ in the case of a polymer stretched film for thinning the optical laminate, and 0.1 to 5 ㎛ in the case of a liquid crystal polymer film, but is not limited thereto.

The above refractive index control layer is provided to compensate for the refractive index difference of the optical laminate due to the transparent conductive layer, and may serve to improve visibility characteristics, etc. by reducing the refractive index difference. In addition, the refractive index control layer may be provided to correct the color caused by the transparent conductive layer. Meanwhile, when the transparent conductive layer (110-2, 120-2) described below has a pattern, the difference in transmittance between the pattern area where the pattern is formed and the non-pattern area where the pattern is not formed can be compensated for through the refractive index control layer.

Specifically, the transparent conductive layer is laminated adjacent to another member having a different refractive index, and a difference in light transmittance may be induced due to the difference in refractive index with respect to the adjacent other layer, and in particular, when a pattern is formed on the transparent conductive layer, a problem may occur in which the pattern area and the non-pattern area are distinguished and recognized. Therefore, by including the refractive index control layer, the difference in light transmittance of the optical laminate can be reduced by compensating for the refractive index, and in particular, when a pattern is formed on the transparent conductive layer, the pattern area and the non-pattern area are not distinguished and recognized.

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

The above refractive index control layer is not particularly limited as long as it can prevent a sharp difference in refractive index between other elements and the transparent conductive layer, and a compound used for forming a refractive index control layer that is conventionally or later developed can be used, and for example, it can be formed from a refractive index control layer forming composition containing a polymerizable isocyanurate compound.

In one embodiment, the polarizing plate (110, 120) may further include, in addition to the functional layer described above, another functional layer to assist or enhance the characteristics of the polarizing plate, and for example, may further include an overcoat layer, etc. to further enhance mechanical durability.

In one or more embodiments, the polarizing plate (110, 120) may have a thickness of 30 to 200 μm, preferably 30 to 170 μm, and more preferably 50 to 150 μm. In this case, the polarizing plate (110, 120) can be used to manufacture an optical laminate having a thin thickness while maintaining optical properties.

The above transparent conductive layers (110-2, 120-2) are provided for driving the liquid crystal layer (130) described later, and may be formed in direct contact with the polarizing plates (110, 120). For example, as illustrated in FIG. 2, the first transparent conductive layer (110-2) and the second transparent conductive layer (120-2) may be formed in direct contact with the first polarizing plate (110) and the second polarizing plate (120), respectively.

Conventionally, optical laminates used in the manufacture of smart windows and the like have been manufactured by forming a conductive layer for driving liquid crystals on one surface of a substrate and bonding the other surface of the substrate with a polarizing plate. However, the optical laminate with variable transmittance according to the present invention is characterized in that the thickness of the laminate is reduced while the transmittance and bending characteristics in the light transmission mode are improved by directly forming the conductive layer on one surface of a polarizing plate without including a separate substrate for forming the conductive layer.

In one embodiment, the transparent conductive layer (110-2, 120-2) may be formed by direct deposition on one surface of the polarizing plate (110, 120). At this time, the transparent conductive layer may be formed by directly contacting the surface of the polarizing plate (110, 120) that has been pretreated after performing pretreatment such as corona treatment or plasma treatment on one surface of the polarizing plate (110, 120) in order to improve adhesion to the polarizing plate (110, 120). The pretreatment is not limited to corona treatment or plasma treatment, and any pretreatment process that is conventionally or later developed may be used within a scope that does not harm the purpose of the present invention.

In another embodiment, the transparent conductive layer (110-2, 120-2) may be formed in direct contact with the polarizing plate, with an adhesive-friendly layer (not shown) provided on one surface of the polarizing plate interposed therebetween, in order to improve adhesion to the polarizing plate. The adhesive-friendly layer may use the adhesive and/or adhesive material described in the other components described below for the adhesive layer, but is not limited thereto.

The above transparent conductive layer (110-2, 120-2) preferably has a visible light transmittance of 50% or more, and may include, for example, at least one 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 a material of a transparent conductive layer developed in the past or later may be used.

In one or more embodiments, the transparent conductive oxide may include at least one selected from the group consisting of indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), aluminum zinc oxide (AZO), gallium zinc oxide (GZO), fluorine tin oxide (FTO), and zinc oxide (ZnO). In addition, the metal may include at least one 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, and may include, for example, a silver-palladium-copper (APC) alloy or a copper-calcium (CuCa) alloy. The above carbon-based material may include at least one selected from the group consisting of carbon nanotubes (CNTs) and graphene, and the conductive polymer may include at least one selected from the group consisting of polypyrrole, polythiophene, polyacetylene, PEDOT, and polyaniline. The conductive ink may be an ink in which a metal powder and a curable polymer binder are mixed, and the nanowire may be, for example, a silver nanowire (AgNW).

In addition, the transparent conductive layer (110-2, 120-2) may be formed into a two-layer or more structure by combining the above materials. For example, it may be formed into a two-layer structure including a metal layer and a transparent conductive oxide layer to lower the reflectivity of incident light and increase the transmittance.

The above transparent conductive layer (110-2, 120-2) can be formed by a method commonly used in the field, and for example, can be formed by selecting an appropriate process from among coating processes such as a spin coating method, a roller coating method, a bar coating method, a dip coating method, a gravure coating method, a curtain coating method, a die coating method, a spray coating method, a doctor coating method, and a kneader coating method; printing processes such as a screen printing method, a spray printing method, an inkjet printing method, a lithographic printing method, a plate printing method, and a flat printing method; and a deposition process such as a CVD (chemical vapor deposition), a PVD (physical vapor deposition), and a PECVD (plasma enhanced chemical vapor deposition).

The above liquid crystal layer (130) can change the driving mode of the optical laminate by controlling the transmittance of light incident from one or more directions depending on the electric field.

The above liquid crystal layer (130) may include a liquid crystal compound and may be positioned, for example, within a space provided by a sealant layer (not shown) and a spacer (not shown) provided between the first polarizing plate (110) and the second polarizing plate (120) in the light control region.

The above liquid crystal compound is not particularly limited as long as it is capable of controlling the light transmittance by being driven by an electric field, and a liquid crystal compound developed in the past or later can be used. For example, the content regarding the reactive liquid crystal compound of the above-described coated polarizer can be equally applied.

In one embodiment, the liquid crystal layer (130) may be driven in a TN (Twisted Nematic) mode. In this case, the optical design with the polarizing plate (110, 120) described above may improve the transmittance variable range between the light-transmitting mode and the light-shielding mode of the optical laminate, and there may be an advantage in that the optical laminate can be easily enlarged.

The above spacer may include at least one of a ball spacer and a column spacer, and is particularly preferably a ball spacer. The ball spacer may be one or more, and is preferably 1 to 10 μm in diameter. In addition, when viewed in a planar direction, the area occupied by the ball spacer in the liquid crystal layer (130) is preferably 0.01 to 10% of the area of the liquid crystal layer (130) in terms of user visibility and improved transmittance in a light-transmitting mode, but is not limited thereto.

In one embodiment, the liquid crystal layer (130) may further include other members within a range that does not impair the purpose of the present invention, for example, may further include a sealant, an alignment film, a point-adhesive layer, and/or an ultraviolet absorbing layer, and may be formed on both sides of the liquid crystal layer (130) including a liquid crystal compound.

The above sealant may include a curable resin as a base resin. As the base resin, an ultraviolet-curable resin or a thermosetting resin known in the art to be usable for a sealant may be used. The ultraviolet-curable resin may be a polymer of an ultraviolet-curable monomer. The thermosetting resin may be a polymer of a thermosetting monomer.

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

The above sealant can be formed by a method commonly used in the art, for example, by drawing the sealant onto the outer surface (i.e., the inactive area) of the liquid crystal layer using a dispenser having a nozzle.

The above-mentioned alignment film is not particularly limited as long as it is for adding orientation to the liquid crystal compound. For example, the alignment film can be produced by applying and curing an alignment film coating composition containing an orientation polymer, a photopolymerization initiator, and a solvent. The alignment polymer is not particularly limited, but a polyacrylate-based resin, a polyamic acid resin, a polyimide-based resin, a polymer containing a cinnamate group, etc. can be used, and a polymer capable of exhibiting orientation that has been developed in the past or in the future can be used.

The above-mentioned adhesive layer can be formed using an adhesive or a pressure-sensitive adhesive, and it is preferable that it have appropriate pressure-sensitive adhesive strength so that peeling, bubbles, etc. do not occur when handling the optical laminate, while also having transparency and thermal stability.

The above adhesive may be a conventional or later-developed adhesive, and for example, a photocurable adhesive may be used. The photocurable adhesive exhibits strong adhesive strength by being crosslinked and cured by receiving active energy rays such as ultraviolet (UV) rays and electron beams (EB), and may be composed of a reactive oligomer, a reactive monomer, a photopolymerization initiator, etc.

The above reactive oligomer is an important component that determines the properties of the adhesive, and forms a polymer bond through a photopolymerization reaction to form a cured film. Usable reactive oligomers include polyester resins, polyether resins, polyurethane resins, epoxy resins, polyacrylic resins, and silicone resins.

The above reactive monomer acts as a crosslinker and diluent of the above-mentioned reactive oligomer and affects the adhesive properties. The reactive monomers that can be used include monofunctional monomers, polyfunctional monomers, epoxy monomers, vinyl ethers, and cyclic ethers.

The above photopolymerization initiator plays a role in initiating photopolymerization by absorbing light energy to generate radicals or cations, and an appropriate one can be selected and used depending on the photopolymerization resin.

The adhesive may be a conventional or later-developed adhesive, and in one or more embodiments, an acrylic adhesive, a rubber adhesive, a silicone adhesive, a urethane adhesive, a polyvinyl alcohol adhesive, a polyvinyl pyrrolidone adhesive, a polyacrylamide adhesive, a cellulose adhesive, a vinyl alkyl ether adhesive, or the like may be used. The adhesive is not particularly limited as long as it has adhesive strength and viscoelasticity, but in terms of ease of acquisition, etc., it may preferably be an acrylic adhesive, and may include, for example, a (meth)acrylate copolymer, a crosslinking agent, a solvent, or the like.

The crosslinking agent may be a crosslinking agent that has been developed in the past or will be developed in the future, and may include, for example, a polyisocyanate compound, an epoxy resin, a melamine resin, a urea resin, dialdehydes, a methylol polymer, etc., and preferably, a polyisocyanate compound.

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

The thickness of the above-described adhesive layer may be appropriately determined depending on the type of resin that acts as the adhesive, the adhesive strength, the environment in which the adhesive is used, etc. In one embodiment, the adhesive layer may have a thickness of 0.01 to 50 μm, preferably 0.05 to 20 μm, and more preferably 0.1 to 10 μm, in order to secure sufficient adhesive strength and minimize the thickness of the optical laminate, but is not limited thereto.

The above ultraviolet absorbing layer is not particularly limited as long as it prevents 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-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-Hydroxy-3'-(3",4",5",6"-tetrahydrophthalimidemethyl)-5'-methylphenyl)benzotriazole, 2,2-Methylenebis(4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol), 2-(2'-Hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-Hydroxy-3'-tert-butyl-5'-(2-octyloxycarbonylethyl)-phenyl)-5-chlorobenzotriazole, 2-(2'-Hydroxy-3'-(1-methyl-1-phenylethyl)-5'-(1,1,3,3-tetramethylbutyl)-phenyl)benzotriazole, 2-(2H-benzotriazol-2-yl)-6-(linear and branched dodecyl)-4-methylphenol, mixtures of octyl-3-[3-tert-butyl-4-hydroxy-5-(chloro-2H-benzotriazol-2-yl)phenyl]propionate and 2-ethylhexyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazol-2-yl)phenyl]propionate, etc.), cyanoacrylate-based ultraviolet absorbers (2'-ethylhexyl-2-cyano-3,3-diphenylacrylate, ethyl-2-cyano-3-(3',4'-methylenedioxyphenyl)-acrylate, etc.), triazine-based ultraviolet absorbers, etc., can be used, and benzotriazole-based ultraviolet absorbers with high transparency and excellent effect in preventing deterioration of polarizing plates or variable transmittance layers, Triazine-based UV absorbers are preferred, and benzotriazole-based UV absorbers having a more appropriate spectral absorption spectrum are particularly preferred. The benzotriazole-based UV absorbers may be bis-based, and examples thereof include 6,6'-methylenebis(2-(2H-benzo[d][1,2,3]triazol-2-yl)-4-(2,4,4-trimethylpentan-2-yl)phenol), 6,6'-methylenebis(2-(2H-benzo[d][1,2,3]triazol-2-yl)-4-(2-hydroxyethyl)phenol), and the like.

<Method for manufacturing optical laminate with variable transmittance>

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

For example, in the polarizing plate, the formation of the conductive layer can be produced by coating a functional conductive layer-forming composition on a triacetyl cellulose film or a cycloolefin polymer (COP) and then bonding it to a polyvinyl alcohol-based polarizer, or by selectively coating a functional conductive layer composition on the triacetyl cellulose film or the cycloolefin film side of the polarizing plate produced by bonding a triacetyl cellulose film or a triacetyl cellulose film and a cycloolefin film to each other via an adhesive on both sides of a polyvinyl alcohol-based polarizer (23 μm, KURARAY).

< Smart Window >

The present invention includes, in addition to the optical laminate, a smart window including the same. In addition, the present invention includes an automobile in which the smart window is applied to at least one of a front window, a rear window, a side window, a sunroof window, and an interior partition, and a window for a building including the smart window.

A car including a smart window of the present invention may be manufactured by bonding vehicle glass to both sides of an optical laminate including a liquid crystal layer and an optical functional layer using an adhesive. For example, an adhesive film and vehicle glass may be placed on both sides of the optical laminate, and then heated for 10 to 20 minutes at a temperature of 90° C. and about 1 bar or in a vacuum using a press machine, or may be manufactured by coating a resin on one side of the vehicle glass, and then vacuum bonding the vehicle glass to both sides of the optical laminate, followed by UV curing. The adhesive film may include an EVA (ethylene vinyl acetate) film, a PVB (polyvinyl butyral) film, or the like, and the resin may include an OCR resin having a storage modulus (G') of 10 ³ to 10 ⁵ Pa.

In addition, a building window (window glass) may be bonded to one or both sides of the optical laminate, a smart window product may be manufactured by bonding window glass to one side of the optical laminate using a laminate method, and a smart window product may be manufactured by bonding window glass to both sides of the optical laminate using a UV adhesive and then UV curing.

Hereinafter, embodiments of the present invention will be specifically described. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and these embodiments are provided only to ensure that the disclosure of the present invention is complete, and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. "%" and "part" in the examples mean "mass%" and "mass part", respectively, unless specifically stated otherwise.

Manufacturing Example 1: Manufacturing of a composition for forming an absorbing layer

30 parts by weight of multifunctional acrylate (MIRAMER M340, Miwon Specialty Chemical Co., Ltd.), 1.5 parts by weight of dye (FDG-05, Yamada Chemical), 50 parts by weight of nano silica sol (12 nm, solid content 40%) dispersed in propylene glycol monomethyl ether, 17 parts by weight of ethyl acetate, 2.7 parts by weight of photoinitiator (I-184, Ciba Co., Ltd.), and 0.3 parts by weight of silicone additive (BYK Co., BYK-UV3530) were mixed using a stirrer and filtered using a polypropylene (PP) filter to prepare a composition for forming a light-absorbing layer.

Manufacturing Example 2: Manufacturing of a composition for forming an alignment film

A composition for forming an alignment film was obtained by mixing 2 parts of an alignment material compound B synthesized by the method described in Japanese Patent Application Laid-Open No. 2013-33248, which is represented by the structural formula below, and 98 parts of o-xylene (Daijung Chemicals & Metals Co., Ltd.) as a solvent, and stirring the resulting mixture at 80°C for 1 hour.

(Compound B)

Manufacturing Example 3: Preparation of a composition for forming a hard coating layer

30 parts by weight of multifunctional acrylate (MIRAMER M340, Miwon Specialty Chemical Co.), 50 parts by weight of propylene glycol monomethyl ether dispersion, nano silica sol (12 nm, solid content 40%), 17 parts by weight of ethyl acetate, 2.7 parts by weight of photoinitiator (Ciba Co., I-184), and 0.3 parts by weight of silicone additive (BYK Co., BYK-UV3530) were mixed using a stirrer and filtered using a polypropylene (PP) filter to prepare a composition for forming a light-absorbing layer.

Manufacturing Example 4: Production of a hard coating layer

The hard coating layer-forming composition of Manufacturing Example 3 was coated on KONICA's transparent triacetyl cellulose (TAC) film KC4UAW (40 um) or KONICA's TAC phase difference film KC3PR-1 (Re 53 nm, Rth 128 nm), and then the solvent was dried and UV-cured to produce a hard coating layer.

Manufacturing Example 5: Manufacturing of a first polarizing plate including a stretchable polarizer

(1) Swelling treatment process

A 60 ㎛ thick polyvinyl alcohol film (fabric film) (manufactured by Kuraray Co., Ltd., trade name "Kurare Poval Film VF-PE#6000", average degree of polymerization 2400, degree of saponification 99.9 mol%) was continuously unwound from a fabric roll and conveyed, and immersed in a swelling bath containing pure water at 20°C for 30 seconds. In this swelling treatment process, inter-rolling (longitudinal uniaxial stretching) was performed by providing a difference in peripheral speed between the nip rolls. The stretching ratio based on the fabric film was 3.5 times.

(2) Dyeing process

Next, the film that passed through the nip roll was immersed in a dyeing bath at 30°C with a mass ratio of pure water/potassium iodide/iodine/boric acid of 100/2/0.01/0.3 for 120 seconds. In this dyeing treatment as well, inter-rolling (longitudinal uniaxial stretching) was performed by providing a difference in peripheral speed between the nip rolls. The stretching ratio based on the film after the swelling treatment process was set to 1.1 times.

(3) Cross-linking process

Next, the film that had passed through the nip roll was immersed in a first crosslinking bath having a mass ratio of pure water/potassium iodide/boric acid of 100/12/4 at 56°C for 70 seconds. Roll-to-roll stretching (longitudinal uniaxial stretching) was performed by providing a difference in peripheral speed between the nip roll and the nip roll provided between the first crosslinking bath and the second crosslinking bath. The stretching ratio based on the film after the dyeing treatment process was set to 1.9 times.

(4) Complementary color treatment process

Next, the film after cross-linking treatment was immersed in a second cross-linking bath at 40°C with a mass ratio of potassium iodide/boric acid/pure water of 9/2.9/100 for 10 seconds.

(5) Cleaning process

Next, the film after the second cross-linking treatment was immersed in a washing bath containing pure water at 14°C for 5 seconds, and washed with a shower amount of 5 m ³ /h and a shower temperature of 14°C.

At this time, the [PVA ⁺ I ₃ ^- ] complex that absorbs the short-wavelength region has a weak characteristic to water, so the group transmission color b* value varies greatly depending on the cleaning solution temperature, cleaning solution retention time, shower amount, shower temperature, and PVA moisture content.

(6) Drying process

Next, the film after the cleaning process was passed through a drying oven, and was dried by heating at 80°C for 190 seconds to produce a polarizer film. The moisture content after drying was 13.6%, and the thickness of the obtained polarizer film was approximately 21 μm.

(7) Bonding process

Next, as an adhesive, an aqueous adhesive containing 5 parts by mass of an acetoacetyl group-modified polyvinyl alcohol-based resin (Cosenol Z200, Nippon Synthetic Chemical Industry Co., Ltd.) per 100 parts by mass of water was prepared. Thereafter, a protective film was laminated on both sides of the polarizer film using the prepared UV adhesive so that the TAC side and the transparent triacetyl cellulose film (TAC, 40 μm) of Manufacturing Example 4 faced the polarizer film. The obtained laminate was exposed to UV light and the adhesive was cured to produce a polarizing plate. In addition, the thickness of the adhesive layer in the obtained polarizing plate was about 2 μm.

Manufacturing Example 6: Manufacturing of a second polarizing plate including a reflective polarizer

After coating the composition for forming an absorption layer of the above Manufacturing Example 1 on a reflective polarizer (APF, 3M), the solvent was dried and UV-cured to form an absorption layer with a thickness of 400 nm on the reflective polarizer, thereby manufacturing a second polarizing plate.

Manufacturing Example 7: Manufacturing of transparent conductive layer

A sputter gun was operated by applying 450 W DC power to the polarizing plate of the above Manufacturing Example 5 or Manufacturing Example 6, and then plasma was induced on the ITO (10 wt% Sn doped In ₂ O ₃ ) target to form a transparent conductive film (90 nm). The formed transparent conductive film was ion-treated by operating an ion gun with 50 W DC power. At this time, the pressure was maintained at 3 mTorr at room temperature, and argon gas and oxygen gas were supplied at 30 sccm and 1 sccm, respectively, while manufacturing. At this time, the ITO performance, the ITO thickness, was measured using FT-SEM, and the ITO sheet resistance (Ω/□) was measured using a Four point probe.

Manufacturing Example 8: Manufacturing of ball spacer dispersion

The mixed solvent was prepared by mixing 0.03 g of the ball spacer (SEKISUI SP-210) of the following example with 100 ml of IPA. The conductive polarizing plate of Manufacturing Example 8 was placed in a spacer spreader (SDSS-KHU02, Shindogiyeon), and the prepared mixed solvent was spread at 110°C and dried for 20 minutes to form a ball spacer on the alignment film of the second polarizing plate.

Manufacturing Example 9: Manufacturing of sealant

In Manufacturing Example 5, a sealant (UVF-006, 70,000 mPa s, SEKISUI) was applied on the transparent conductive layer of the second polarizing plate using a sealant dispenser (SHOTmini 200Ωx, USASHI) at a discharge pressure of 200 mPa using a sharp needle (SPN-0.25-12.7 L) in accordance with the product size drawing, and a liquid crystal driven in TN (Twisted Nematic) mode was injected onto the alignment film using the ODF process. Thereafter, the first polarizing plate and the second polarizing plate were bonded at a pressure of 3 kg/cm ² while their transmission axes were 90° to each other and their machine directions (MDs) were arranged parallel to each other (0°) in the plane direction, and then UV curing (500 mJ/cm ² ) was performed along the sealant line.

Examples and Comparative Examples: Manufacturing of Optical Laminates

According to the above manufacturing examples 1 to 9, an optical laminate is manufactured. The first polarizing plate and the second polarizing plate of each example and comparative example shall follow the contents described in Table 1.

division 1st polarizing plate Second polarizing plate Example 1 Extendable polarizer Reflective polarizer + absorbing layer
(Polarizing plate according to Manufacturing Example 6) Comparative Example 1 Extendable polarizer reflective polarizer

-Extensible polarizer: The extended polarizer of the above manufacturing example 5

- Reflective polarizer: APF, 3M

Experimental example

(1) Evaluation of visible light transmittance and reflectance

For the optical laminates of the above examples and comparative examples, the transmittance and reflectance were measured in the voltage-applied (ON) and unapplied (OFF) states using CM3700 (Konica Minolta), and the results are shown in Table 2 below.

division Transmittance reflectivity Voltage OFF (Tmax) Voltage ON (Tmin) Voltage OFF (Tmax) Voltage ON (Tmin) Example 1 18% 0.1% 14.4% 14.0% Comparative Example 1 35% 0.2% 57.6 % 55.8%

Referring to the above experimental data, it was confirmed that the transmittance variable optical laminate according to the present invention has a characteristic of maintaining the transmittance while having a low reflectance of 15% or less, compared to Comparative Example 1 that does not include a coated polarizer by applying only a stretchable polarizer to both the first polarizing plate and the second polarizing plate. Therefore, it can be confirmed that the transmittance variable optical laminate of the present invention can be manufactured by a roll-to-roll manufacturing process, and is suitable for manufacturing a large-area transmittance variable optical laminate.

100: Transmittance variable optical laminate
110: 1st polarizing plate
110-1: 1st polarizer
110-2: 1st transparent conductive layer
120: 2nd polarizing plate
120-1: Second polarizer
120-2: Second transparent conductive layer
130: Liquid crystal layer
140: Absorbing layer

Claims (20)

liquid crystal layer;
A first transparent conductive layer formed on one surface of the liquid crystal layer;
A second transparent conductive layer formed on the other surface of the liquid crystal layer;
A first polarizing plate formed on the first transparent conductive layer; and
A second polarizing plate formed on the second transparent conductive layer is included.
At least one of the first polarizing plate and the second polarizing plate includes a reflective polarizer and an absorption layer,
A variable transmittance optical laminate, wherein the transmission axes of each of the first polarizing plate and the second polarizing plate are perpendicular. In claim 1,
The first polarizing plate and the second polarizing plate are a transmittance variable optical laminate, each of whose machine directions (MDs) are parallel to each other. In claim 1,
The above-mentioned variable transmittance optical laminate is a variable transmittance optical laminate manufactured by a roll-to-roll continuous process. In claim 1,
A transmittance variable optical laminate, wherein at least one of the first polarizing plate and the second polarizing plate comprises a stretchable polarizer. In claim 1,
A variable transmittance optical laminate having a reflectivity of 15% or less. In claim 1,
A transmittance variable optical laminate, wherein at least one of the first polarizing plate and the second polarizing plate includes at least one functional layer selected from the group consisting of a functional coating layer, a protective layer, a phase difference control layer, and a refractive index control layer. In claim 1,
A transmittance variable optical laminate, wherein at least one of the first polarizing plate and the second polarizing plate has a thickness of 30 to 200 μm. In claim 1,
A transmittance variable optical laminate, wherein at least one of the first transparent conductive layer and the second transparent conductive layer is formed in direct contact with one of the first polarizing plate and the second polarizing plate without including a separate substrate therebetween. In claim 1,
A transmittance variable optical laminate, wherein at least one of the first transparent conductive layer and the second transparent conductive layer further includes an adhesive-friendly layer between the first and second polarizing plates, and is formed in direct contact with the polarizing plate. In claim 1,
A transmittance variable optical laminate, wherein at least one of the first transparent conductive layer and the second transparent conductive layer comprises at least one selected from the group consisting of transparent conductive oxides, metals, carbon-based materials, conductive polymers, conductive inks, and nanowires. In claim 1,
The above liquid crystal layer is a transmittance variable optical laminate driven in TN (Twisted Nematic) mode. In claim 1,
A variable transmittance optical laminate, wherein the liquid crystal layer comprises at least one spacer selected from the group consisting of a ball spacer and a column spacer. In claim 1,
A variable transmittance optical laminate, wherein the variable transmittance optical laminate further comprises at least one member selected from the group consisting of a sealant, an alignment film, a point-based adhesive layer, and an ultraviolet absorbing layer. A method for manufacturing a variable transmittance optical laminate according to any one of claims 1 to 13. In claim 14,
A method for manufacturing a variable transmittance optical laminate, characterized in that the method for manufacturing the variable transmittance optical laminate is a roll-to-roll continuous process. A smart window comprising a variable transmittance optical laminate according to any one of claims 1 to 13. A means of transportation comprising a smart window according to claim 16. A vehicle having the smart window of claim 16 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 comprising a smart window of claim 16. An architectural window comprising a smart window according to claim 16.