KR20230045528A - Optical laminate, and manufacturing method for the same, and smart window including the same, and automobile or windows for buiding using the same - Google Patents

Abstract

The present invention relates to a variable-transmittance optical laminate and a manufacturing method thereof, a smart window including the same, and a vehicle or building window applied therewith. The variable-transmittance optical laminate comprises: a first polarizing plate including a first polarizer and a polarization rotating layer; a first transparent conductive layer formed on one surface of the first polarizing plate; a second polarizing plate including a second polarizer and a phase difference layer, and facing the first polarizing plate; a second transparent conductive layer formed on one surface of the second polarizing plate, and facing the first transparent conductive layer; and a liquid crystal layer provided between the first and second transparent conductive layers. At least one of the first and second transparent conductive layers are formed in direct contact with any one of the first and second polarizing plates. The polarization rotating layer has reverse wavelength or flat wavelength dispersion characteristics, and the phase difference layer includes a negative C-plate. Therefore, the transmittance is improved.

Description

Optical laminate and its manufacturing method, smart window including the same, and window for automobile or building using the same

The present invention relates to a variable transmittance optical laminate, a manufacturing method thereof, a smart window including the same, and windows and doors for automobiles or buildings to which the same is applied.

In general, there are many cases in which an external light blocking coating is applied to a window of a means of transportation such as a vehicle. However, the transmittance of a window of a conventional means of transportation is fixed, and the external light blocking coating also has a fixed transmittance. Therefore, the entire transmittance of the window of the conventional means of transportation is fixed, which may cause an accident. For example, if the overall transmittance is set low, there is no problem during the daytime when the ambient light is sufficient, but at night when the ambient light is not sufficient, the driver may have difficulty properly checking the surroundings of the means of transportation. There was a problem. Alternatively, if the overall transmittance is set high, there is a problem in that glare may be caused to the driver or the like during the day when the amount of ambient light is sufficient. Accordingly, an optical laminate with variable transmittance capable of changing light transmittance when a voltage is applied has been developed.

The variable transmittance optical laminate is driven by driving the liquid crystal according to the application of voltage and changing the transmittance. In the variable transmittance optical laminate developed to date, a conductive layer for driving the liquid crystal is formed on a separate substrate, It is manufactured by combining this with other elements such as a polarizing plate.

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

However, when a separate base material is included to form the conductive layer in this way, as the manufacturing process becomes complicated, the manufacturing cost increases, the thickness of the laminate becomes thick, and the transmittance changes due to the occurrence of a phase difference. there is.

Therefore, by not including a separate substrate for forming the conductive layer, the production process is simplified, and development of a variable transmittance optical laminate capable of reducing the thickness is required.

Japanese Laid-open Patent No. 2018-010035

An object of the present invention is to provide a variable transmittance optical laminate having a simplified manufacturing process by not including a separate substrate for forming a conductive layer.

In addition, an object of the present invention is to provide a variable transmittance optical laminate having a significantly reduced thickness by not including a separate substrate for forming a conductive layer.

In addition, an object of the present invention is to provide a variable transmittance optical laminate having improved transmittance in a light transmission mode by not including a separate substrate for forming a conductive layer.

In addition, an object of the present invention is to provide a variable transmittance optical laminate with improved light blocking properties in a light blocking mode by adjusting the wavelength dispersion characteristics of a polarization rotation layer included in a polarizing plate.

In addition, an object of the present invention is to provide a variable transmittance optical laminate with improved light-shielding properties in a light-shielding mode by adjusting the characteristics of a retardation layer included in a polarizing plate.

In addition, an object of the present invention is to provide a smart window including the variable transmittance optical laminate and a window for a vehicle or building to which the same is applied.

However, the problem to be solved by the present invention is 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.

A first polarizing plate comprising a first polarizer and a polarization rotation layer; a first transparent conductive layer formed on one surface of the first polarizing plate; a second polarizing plate including a second polarizer and a retardation layer and facing the first polarizing plate; a second transparent conductive layer formed on one surface of the second polarizing plate and facing the first transparent conductive layer; and a liquid crystal layer provided between the first transparent conductive layer and the second transparent conductive layer, wherein at least one transparent conductive layer of the first transparent conductive layer and the second transparent conductive layer comprises the first polarizing plate and the second transparent conductive layer. It is formed in direct contact with any one of the two polarizers, the polarization rotation layer has reverse wavelength or flat wavelength dispersion characteristics, and the retardation layer includes a negative C plate. It's about laminates.

In the first aspect of the present invention, the polarization rotation layer may be provided on an inner side with respect to the first polarizer.

In the second aspect of the present invention, the polarization rotating layer has an in-plane retardation value (R _in (550)) at a wavelength of 450 nm relative to an in-plane retardation value (R _in (550)) at a wavelength of 550 nm. The ratio (R _in (450)/R _in (550)) may be 0.75 to 1.0.

In the third aspect of the present invention, the polarization rotation layer may include a single- or multi-layer half-wave plate.

In the fourth aspect of the present invention, the in-plane retardation value (R _in ) of the half-wave plate may be 250 to 300 nm.

In the fifth aspect of the present invention, the retardation layer may be provided on the inner side with respect to the second polarizer.

In the sixth aspect of the present invention, the thickness direction retardation value (R _th ) of the retardation layer may be 10 to 500 nm.

In the seventh aspect of the present invention, an absorption axis of the first polarizer and an absorption axis of the second polarizer may be parallel to each other.

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

In the ninth aspect of the present invention, at least one transparent conductive layer of the first transparent conductive layer and the second transparent conductive layer is separated from any one of the first polarizing plate and the second polarizing plate. It may be formed by direct contact without including a substrate of.

In the tenth aspect of the present invention, at least one transparent conductive layer of the first transparent conductive layer and the second transparent conductive layer is bonded to any one of the first polarizing plate and the second polarizing plate. It may be formed by direct contact, including an easy layer.

In the eleventh aspect of the present invention, at least one transparent conductive layer of the first transparent conductive layer and the second transparent conductive layer is made of a transparent conductive oxide, metal, carbon-based material, conductive polymer, conductive ink, and nanowire. It may include one or more selected from the group.

In the twelfth 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 and a refractive index adjusting layer.

In the thirteenth 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.

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

In the fifteenth aspect of the present invention, the ball spacer may have a diameter of 1 to 10 μm.

In the sixteenth aspect of the present invention, the area occupied by the ball spacer in the liquid crystal layer may be 0.01% to 10% of the area of the liquid crystal layer.

In the seventeenth aspect of the present invention, the variable transmittance optical laminate may further include at least one selected from the group consisting of an alignment film, an adhesive layer, an ultraviolet ray absorbing layer, and a hard coating layer.

Further, the present invention relates to a method for manufacturing the variable transmittance optical laminate.

In addition, the present invention relates to a smart window including the variable transmittance optical laminate.

In addition, the present invention relates to a vehicle in which the smart window is applied to at least one or more of a front window, a rear window, a side window, a sunroof window, and an interior partition.

In addition, the present invention relates to a window for a building, including the smart window.

According to the variable transmittance optical laminate according to the present invention, it is possible to omit the process of forming a conductive layer on a substrate and bonding it to another member in order to form a conventional optical laminate. Contrast manufacturing process can be simplified.

In addition, according to the variable transmittance optical laminate according to the present invention, the conductive layer is formed directly on one surface of the polarizing plate, and the thickness is significantly reduced compared to the conventional optical laminate by not including a separate substrate for forming the conductive layer. it could be

In addition, according to the variable transmittance optical laminate according to the present invention, a conductive layer is directly formed on one surface of the polarizing plate, and a separate substrate for forming the conductive layer is not included, so that the transmittance in the light transmission mode is higher than that of the conventional optical laminate. this may be improved.

In addition, according to the variable transmittance optical laminate according to the present invention, by adjusting the wavelength dispersion characteristics of the polarization rotation layer included in the polarizing plate, the light blocking property in the light blocking mode may be improved compared to the conventional optical laminate.

In addition, according to the variable transmittance optical laminate according to the present invention, since the retardation layer included in the polarizing plate includes a negative C plate, the light blocking property in the light blocking mode may be improved compared to the conventional optical laminate, In particular, the side light leakage phenomenon may be further reduced.

1 is a diagram showing a laminated structure of a variable transmittance optical laminate according to an embodiment of the present invention.
2 is a diagram showing a laminated structure of a polarizing plate according to one or more embodiments of the present invention.
3 is a diagram showing an absorption axis and a transmission axis of a roll-type film master providing a polarizer according to an embodiment of the present invention.
4 is a diagram showing a laminated structure of a variable transmittance optical laminate according to another embodiment of the present invention.

The present invention relates to a variable transmittance optical laminate including a polarization rotation layer and a retardation layer. The thickness of the laminate is reduced and the transmittance in the light transmission mode is improved, and the light blocking property in the light blocking mode can be improved by adjusting the wavelength dispersion characteristics of the polarization rotation layer and the characteristics of the retardation layer. In particular, side light leakage is improved. It relates to a variable transmittance optical laminate capable of further reducing a phenomenon.

More specifically, a first polarizing plate comprising a first polarizer and a polarization rotation layer; a first transparent conductive layer formed on one surface of the first polarizing plate; a second polarizing plate including a second polarizer and a retardation layer and facing the first polarizing plate; a second transparent conductive layer formed on one surface of the second polarizing plate and facing the first transparent conductive layer; and a liquid crystal layer provided between the first transparent conductive layer and the second transparent conductive layer, wherein at least one transparent conductive layer of the first transparent conductive layer and the second transparent conductive layer comprises the first polarizing plate and the second transparent conductive layer. It is formed in direct contact with any one of the two polarizers, the polarization rotation layer has reverse wavelength or flat wavelength dispersion characteristics, and the retardation layer includes a negative C plate. It's about laminates.

The variable transmittance optical laminate of the present invention is particularly suitable for technical fields capable of changing light transmittance according to the application of voltage, and can be used, for example, in a smart window or the like.

A smart window refers to an optical structure that controls the amount of light or heat passing through by changing the transmittance of light according to the application of an electrical signal. That is, the smart window is provided to be changed into a transparent, opaque or translucent state by voltage, and is also called variable transmittance glass, dimming glass, or “smart” glass.

A smart window can be used as a partition for partitioning the interior space of vehicles and buildings or for protecting privacy, or as a skylight placed in an opening of a building, and can be used as a highway sign, bulletin board, scoreboard, clock or advertising screen. It can also be used, and it can be used as a substitute for the glass of vehicles such as windows or sunroofs of cars, buses, aircrafts, ships, or trains.

The variable transmittance optical laminate of the present invention can also be used as a smart window in the various technical fields described above, but since the conductive layer is directly formed on the polarizer, it does not include a separate substrate for forming the conductive layer. It is thin and advantageous in bending properties, so it can be particularly suitably used for smart windows for vehicles or buildings. In one or more embodiments, the smart window to which the variable transmittance optical laminate of the present invention is applied can be used for front windows, rear windows, side windows and sunroof windows of vehicles, or windows and doors for buildings, In addition to the use of blocking external light, it can also be used for partitioning the interior space of a car or building, such as an interior partition, or for protecting privacy.

Hereinafter, with reference to the drawings, an embodiment 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 serve to further understand the technical idea of the present invention together with the contents of the above-described invention, so the present invention is described in such drawings should not be construed as limited to

Terms used herein are for describing the embodiments, and are not intended to limit the present invention. In this specification, singular forms also include plural forms unless specifically stated otherwise in a phrase. For example, as used herein, “polarizing plate” may mean at least one polarizing plate of a first polarizing plate and a second polarizing plate, and “polarizing plate” may mean at least one polarizing plate of a first polarizing plate and a second polarizing plate. It may mean, "transparent conductive layer" may mean at least one transparent conductive layer of the first transparent conductive layer and the second transparent conductive layer, and the "alignment layer" may mean the first alignment layer and the second transparent conductive layer. It may mean at least one alignment layer among the alignment layers.

As used herein, "comprises" and/or "comprising" means the presence or addition of one or more other elements, steps, operations and/or elements other than the mentioned elements, steps, operations and/or elements. is used in the sense of not excluding. Like reference numerals designate like elements throughout the specification.

The spatially relative terms “below”, “bottom”, “lower”, “above”, “upper”, “upper”, etc. refer to one element or component and another element or component as shown in the drawings. It can be used to easily describe the correlation with Spatially relative terms should be understood as encompassing different orientations of elements in use or operation in addition to the orientations shown in the figures. For example, when elements shown in the drawings are turned over, elements described as "below" or "below" other elements may be placed "above" the other elements. Accordingly, the exemplary term “below” may include directions of both down and up. Elements may also be oriented in other orientations, and thus spatially relative terms may be interpreted according to orientation.

As used herein, "planar direction" may be interpreted as a direction orthogonal to the polarizing plate and/or the transparent conductive layer, that is, a direction viewed from the user's viewing side.

1 is a diagram showing a laminated structure of a variable transmittance optical laminate according to an embodiment of the present invention, and FIG. 2 is a diagram showing a laminated structure of polarizing plates according to one or more embodiments of the present invention.

Referring to FIG. 1 , an optical laminate with variable transmittance according to an embodiment of the present invention includes a first polarizing plate 100-1, a second polarizing plate 100-2, a first transparent conductive layer 200-1, It may include the second transparent conductive layer 200 - 2 and the liquid crystal layer 300 .

1 and 2, the first polarizer 100-1 includes a first polarizer 110-1 and a polarization rotation layer 120-1, and the second polarizer 100-2 , may include a second polarizer 110-2 and a retardation layer 120-2.

In one or more embodiments, the polarizing plate 100 may further include functional layers such as a protective layer 130 and a refractive index adjusting layer 140 on one or both surfaces of the polarizer 110 . For example, the polarizer 100 may include a polarization rotation layer or retardation layer 120, a polarizer 110, and a protective layer 130 sequentially stacked (see FIG. 2A), and the polarization rotation layer or retardation layer 120 may be sequentially stacked. The layer 120, the protective layer 130, the polarizer 110, and the protective layer 130 may be sequentially stacked (see FIG. 2B), and the refractive index control layer 140, the polarization rotation layer or the retardation layer ( 120), the polarizer 110, and the protective layer 130 may be sequentially stacked (see FIG. 2C).

For the polarizer 110, a conventional or later developed polarizer may be used, and for example, a stretch type polarizer or a coating type polarizer may be used.

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

In one embodiment, the coating type polarizer may be formed of a liquid crystal coating composition, and in this case, the liquid crystal coating composition may include a reactive liquid crystal compound and a dichroic dye.

The reactive liquid crystal compound is not particularly limited as long as it can exhibit polarization characteristics, and a conventional or later developed reactive liquid crystal compound may be used.

The reactive liquid crystal compound may refer to a compound including, for example, a mesogen backbone and one or more polymerizable functional groups. These reactive liquid crystal compounds are variously known as so-called RM (Reactive Mesogen). The reactive liquid crystal compound may be polymerized by light or heat to form a cured film in which a polymer network is formed while maintaining a liquid crystal arrangement.

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

The dichroic dye is a component that is included in the composition for liquid crystal coating and imparts polarization characteristics, and has a property in which absorbance in the long-axis direction and absorbance in the short-axis direction of the molecule are different. As the dichroic dye, conventional or later developed dichroic dyes may be used, for example, azo dyes, anthraquinone dyes, perylene dyes, merocyanine dyes (merocyanine dyes), azomethine dyes, phthaloperylene dyes, indigo dyes, dioxadine dyes, polythiophene dyes and phenoxazine It may contain at least one selected from the group consisting of dyes (phenoxazine dyes).

The liquid crystal coating composition may further include a solvent capable of dissolving the reactive liquid crystal compound and the dichroic dye, for example, propylene glycol monomethyl ether acetate (PGMEA), methyl ethyl ketone (MEK), xylene (xylene) and chloroform may be used. 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 properties of the coating film.

In an embodiment, an absorption axis of the first polarizer and an absorption axis of the second polarizer may be disposed parallel to each other. In this case, since the absorption axis of the polarizer and the machine direction (Machine Direction; MD) are parallel, it may be advantageous to increase the area of the variable transmittance optical laminate.

Specifically, FIG. 3 is a diagram showing an absorption axis and a transmission axis of a roll-type film master providing a polarizer according to an embodiment of the present invention.

Referring to Figure 3, in the polarizer according to an embodiment of the present invention, the machine direction (Machine Direction; MD) of the polarizer is parallel to the absorption axis of the polarizer, and the transverse direction (TD) is parallel to the transmission axis of the polarizer It can be produced by a roll-to-roll process using film-type disks in the form of rolls provided in parallel.

At this time, when the absorption axes of the two different polarizers are parallel, it is easy to manufacture two polarizers having a predetermined machine direction (MD) length according to the user's needs, which can be advantageous for large-area optical laminates. there is.

The polarization rotation layer 120-1 is for substantially rotating the polarized light passing through the polarizer 110 and the like by 90°, and a conventional or later developed polarization rotation layer may be used, and substantially 90°. It may be, for example, 85° to 95°.

The polarization rotation layer 120-1 may be formed by directly contacting one surface of the first polarizer 110-1 as shown in FIGS. 1, 2A and 2C, but is not limited thereto. For example, as shown in FIG. 2B, the polarization rotation layer 120 is formed on one surface of the protective layer 130, and the polarization rotation layer 120, the protective layer 130, the polarizer 110 and The protective layer 130 may be sequentially stacked.

The polarization rotation layer 120-1 is preferably formed on one surface in the direction of the liquid crystal layer 300 with respect to the first polarizer 110-1, that is, on the inner side of the first polarizer 110-1. do. In this case, there is an advantage in that optical characteristics of light passing through the polarizer 110 can be easily changed.

The polarization rotation layer 120-1 may have reverse wavelength or flat wavelength dispersion characteristics, and preferably may have reverse wavelength dispersion characteristics. When the polarization rotation layer 120-1 has a reverse wavelength or flat wavelength dispersion characteristic, particularly when it has a reverse wavelength dispersion characteristic, the light blocking property of the optical laminate in the light blocking mode can be further improved.

In one or more embodiments, when the polarization rotation layer 120-1 has reverse wavelength dispersion characteristics, the in-plane retardation value (R _in (550)) at 550 nm wavelength at 450 nm wavelength When the ratio (R _{in (} 450)/R _in (550)) of the in-plane retardation value (R in (450)) may be 0.75 or more and less than 1.0, and the polarization rotation layer 120-1 has a flat wavelength dispersion characteristic In , the ratio (R _in (450) _/ R in (550)) of the in-plane retardation value (R _in (450)) at the 450 nm wavelength to the in-plane retardation value (R _in (550)) at the 550 nm wavelength is may be 1.0.

In one or more embodiments, the polarization rotation layer 120-1 may include a single or multi-layer half-wave plate.

When the polarization rotation layer 120-1 includes a single half-wave plate, that is, when it includes one half-wave plate, the characteristics of the polarization rotation layer 120-1 correspond to the characteristics of the half-wave plate. it could be In this case, the half-wavelength plate preferably has reverse wavelength or flat wavelength dispersion characteristics, and the optical axis of the half-wavelength plate is preferably formed to have an angle between 40° and 50° with the absorption axis of the polarizer 110. .

When the polarization rotation layer 120-1 includes a multi-layered half-wave plate, the polarization rotation layer 120-1 passes through the polarizer 110 and the like to substantially rotate polarized light by 90°, The characteristics of the individual half-wavelength plates are not particularly limited as long as they have reverse wavelength or flat wavelength dispersion characteristics. For example, when the polarization rotation layer 120-1 has a two-layer structure of a first half-wave plate and a second half-wave plate, the first half-wave plate and the second half-wave plate are each a reverse-wavelength, forward-wavelength, or flat-wavelength plate. It may have a wavelength dispersion characteristic, the optical axis of the first half-wave plate has an angle of 20° to 25° with the absorption axis or transmission axis of the polarizer 110, and the optical axis of the second half-wave plate has a polarizer 110 It may be formed to have an absorption axis or transmission axis and an angle between 65 ° and 70 °.

In an embodiment, the in-plane retardation value (R _in ) of the half-wave plate may be 250 to 300 nm, and when the polarization rotation layer 120-1 includes one half-wave plate, The in-plane retardation value (R _in ) may satisfy the above range, and when the polarization rotation layer 120-1 includes a plurality of half-wave plates, the in-plane retardation value (R _in ) of each half-wave plate is within the above range. may be satisfactory. When the in-plane retardation of the half-wave plate satisfies the above range, light-blocking properties in a light-blocking mode of the optical laminate may be improved.

For the half-wavelength plate, a stretched polymer film or a liquid crystal polymerization film obtained by stretching a polymer film capable of imparting optical anisotropy by stretching in an appropriate manner may be used.

In one embodiment, the stretched polymer film is made of polyolefin such as polyethylene (PE) or polypropylene (PP), cyclo olefin polymer (COP) such as polynorbornene, polyvinyl chloride (PVC), polyacrylonitrile (PAN), polysulfone (PSU), acrylic resin, polycarbonate (PC), polyethylene terephthalate (polyethylene terephthalate; Polyester such as PET), polyacrylate, polyvinyl alcohol (PVA) or cellulose ester-based polymer such as triacetyl cellulose (TAC), or two types of monomers forming the polymer A polymer layer containing a copolymer of the above monomers or the like can be used.

A method of obtaining the stretched polymer film is not particularly limited, and may be obtained by, for example, stretching the polymer material after forming it into a film form. The forming method into the film form is not particularly limited, and it is possible to mold the film 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 process molding methods such as molding and vacuum molding can also be used. Among them, extrusion molding and cast molding are preferably used. At this time, for example, the unstretched film may be extruded using an extruder equipped with a T die, a circular die, or the like. In the case of obtaining a molded article by extrusion molding, as long as a material obtained by melt-kneading various resin components, additives, etc. in advance can be used, it can also be molded through melt-kneading at the time of extrusion molding. In addition, the unstretched film can also be cast-molded by dissolving the various resin components using a solvent common to the various resin components, for example, a solvent such as chloroform or methylene dichloride, and then casting dry and solidifying the unstretched film.

The polymer stretched film is uniaxially stretched in the mechanical flow direction (MD; Mechanical Direction, longitudinal direction or longitudinal direction) of the molded film, and in a direction (TD; Transverse Direction, transverse direction or width direction) that goes directly to the mechanical flow direction. It can be uniaxially stretched, or a biaxially stretched film can also be produced 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, or the like.

The liquid crystal polymerization film may include a reactive liquid crystal compound in a polymerized state, and a conventional or later developed reactive liquid crystal compound may be used. For example, the above-described information on the reactive liquid crystal compound of the polarizer may be equally applied there is.

The retardation layer 120-2 is for supplementing the optical characteristics of the optical stack, and may include a negative C plate, and accordingly, a side (diagonal direction) light leakage phenomenon in light blocking mode. can be further reduced.

The retardation layer 120-2 may be formed by directly contacting one surface of the second polarizer 110-2 as shown in FIGS. 1, 2A and 2C, but is not limited thereto. For example, as shown in FIG. 2B, the retardation layer 120-2 is formed on one surface of the protective layer 130, and the retardation layer 120, the protective layer 130, the polarizer 110 and The protective layer 130 may be sequentially stacked.

The retardation layer 120-2 is preferably formed on one surface in the direction of the liquid crystal layer 300 with respect to the second polarizer 110-2, that is, on the inner side of the second polarizer 110-2. In this case, there is an advantage in that optical characteristics of light passing through the polarizer 110 can be easily changed.

Hereinafter, the negative C plate included in the retardation layer 120-2 will be described in detail.

Specifically, the retardation layer (or retardation film) is divided into uniaxial and biaxial according to the number of optical axes, and is divided into positive and negative according to the difference in refractive index in the direction of the optical axis and the refractive index in other directions. For example, if there is one optical axis, it is classified as uniaxial, and if there are two, it is classified as biaxial, and if the refractive index in the optical axis direction is greater than the refractive index in other directions, it is positive, and if the refractive index in the optical axis direction is smaller than the refractive index in other directions. classified as negative.

Such a retardation layer can be expressed as a refractive index in each direction in an xyz coordinate system. For example, when the retardation layer is present in the xy plane, the x-axis and the y-axis mean the plane direction of the retardation layer, and the refractive index of nx, ny, and nz along the x-axis, y-axis, and z-axis, respectively. ) has

At this time, the C plate has the same refractive index (nx) in the x-axis direction and the refractive index (ny) in the y-axis direction, and the refractive index (nz) in the z-axis direction is the refractive index (nx) in the x-axis direction and It is characterized in that it is different from the refractive index (ny) in the y-axis direction. If the refractive index (nx) in the x-axis direction and the refractive index (ny) in the y-axis direction are smaller than the refractive index (nz) in the z-axis direction, it is a positive C plate, and the refractive index (nx) in the x-axis direction and the refractive index (nx) in the y-axis direction If the index of refraction (ny) in the direction is greater than the index of refraction (nz) in the z-axis direction, it is a negative C plate.

On the other hand, R _th means a phase retardation (or thickness direction retardation) value in the thickness direction, and is expressed in Equation 1 below.

[Equation 1]

R _th = ((nx + ny)/2 - nz) d

In Equation 1, d represents the thickness of the retardation layer.

In one embodiment, the negative C plate included in the retardation layer 120-2 may have a thickness direction retardation value (R _th ) of 10 to 500 nm, preferably 50 to 400 nm, more preferably, it may be 50 to 300 nm. In this case, there is an advantage in that the side (diagonal direction) light leakage phenomenon in the light blocking mode can be further reduced.

In one or more embodiments, the negative C plate is a Cyclo-Olefin-Polymer (COP) film, a polycarbonate (PC) film, or a UV curable horizontal or horizontal alignment liquid crystal. A film, polystyrene (PS) resin, polyethylene terephthalate (PET), or the like may be used.

In one or more embodiments, the thickness of the retardation layer 120-2 may be 1 μm to 100 μm.

The protective layer 130 is for preserving the polarization characteristics of the polarizer 110 from subsequent processes and external environments, and may be implemented in the form of a protective film.

The protective layer 130 may be formed by directly contacting one side or both sides of the polarizer 110 as shown in FIGS. 2A to 2C , but is not limited thereto. For example, the protective layer may be used in a multilayer structure in which one or more protective layers are continuously stacked, or may be formed in direct contact with another functional layer.

In one or more embodiments, the protective layer 130 may include polyethylene terephthalate (PET), polyethylene isophthalate (PEI), polyethylene naphthalate (PEN), or polybutylene. Terephthalate (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 polymers It may include one or more selected from the group consisting of (cyclic olefin polymer; COP).

The refractive index control layer 140 is provided to compensate for the difference in refractive index of the optical laminate due to the transparent conductive layer 200, and may serve to improve visibility by reducing the difference in refractive index. there is. In addition, the refractive index adjusting layer 140 may be provided to correct color due to the transparent conductive layer 200 . Meanwhile, when the transparent conductive layer has a pattern, a difference in transmittance between a pattern area where the pattern is formed and a non-pattern area where the pattern is not formed may be compensated for through the refractive index adjusting layer 140 .

Specifically, the transparent conductive layer 200 is laminated adjacent to another member (eg, polarizer 110, etc.) having a different refractive index, and a difference in light transmittance may be caused due to a difference in refractive index with another adjacent layer, In particular, when a pattern is formed on the transparent conductive layer, a problem in that the pattern area and the non-pattern area can be distinguished may occur. Therefore, by including the refractive index adjusting layer 140, the refractive index is compensated to reduce the difference in light transmittance of the optical laminate. In particular, when a pattern is formed on the transparent conductive layer, the pattern area and the non-pattern area This distinction is made so that it is not recognized.

In one embodiment, the refractive index of the refractive index adjusting layer 140, but may be appropriately selected according to the material of the other adjacent members, preferably 1.4 to 2.6, more preferably, 1.4 to 2.4 It may be. In this case, light loss due to a sharp difference in refractive index between other members such as the polarizer 110 and the transparent conductive layer 200 can be prevented.

The refractive index control layer 140 is not particularly limited as long as it can prevent a sharp difference in refractive index between other members such as the polarizer 110 and the transparent conductive layer 200, and the refractive index control layer developed conventionally or later. A compound used for formation may be used, and for example, it may be formed from a composition for forming a refractive index control layer containing a polymerizable isocyanurate compound.

In one embodiment, the polarizer 100 may further include other functional layers for assisting or reinforcing the characteristics of the polarizer in addition to the above-described functional layer. For example, in order to further improve mechanical durability, an overcoat It may further include a layer or the like.

In one or more embodiments, the polarizing plate 100 may have a thickness of 30 to 200 μm, preferably 30 to 170 μm, and more preferably 50 to 150 μm. can In this case, while maintaining the optical characteristics of the polarizing plate 100, it is possible to manufacture a thin optical laminate.

The transparent conductive layer 200 is provided for driving the liquid crystal layer 300 and may be formed by directly contacting the polarizing plate 100 . For example, as shown in FIG. 1 , the first transparent conductive layer 200-1 and the second transparent conductive layer 200-2 are the first polarizing plate 100-1 and the second polarizing plate 100-2, respectively. 2) may be formed by direct contact with.

Conventionally, an optical laminate used for manufacturing a smart window or the like is manufactured by forming a conductive layer for driving a liquid crystal on one surface of a substrate and bonding the other surface of the substrate to a polarizing plate. However, the transmittance variable optical laminate according to the present invention does not include a separate substrate for forming the conductive layer and directly forms the conductive layer on one surface of the polarizing plate, thereby reducing the thickness of the laminate and increasing the transmittance in the light transmission mode. And it is characterized in that the flexural properties are improved.

In one embodiment, the transparent conductive layer 200 may be formed by directly depositing on one surface of the polarizing plate 100 . At this time, in order to improve adhesion with the polarizing plate 100, the transparent conductive layer 200 is subjected to a pre-treatment such as corona treatment or plasma treatment on one surface of the polarizing plate 100, and then the pre-treatment of the polarizing plate 100. It may be formed in direct contact with the surface subjected to. The pretreatment is not limited to corona treatment or plasma treatment, and a conventional or later developed pretreatment process may be used within a range that does not impair the object of the present invention.

In another embodiment, the transparent conductive layer 200 is formed with an easy adhesion layer (not shown) provided on one surface of the polarizing plate 100 interposed therebetween to improve adhesion with the polarizing plate 100. It may be formed by direct contact with (100).

The transparent conductive layer 200 preferably has a visible light transmittance of 50% or more. For example, one selected from the group consisting of transparent conductive oxides, metals, carbon-based materials, conductive polymers, conductive inks, and nanowires. It may include the above, but is not limited thereto, and a material of a transparent conductive layer conventionally or later developed may be used.

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

In addition, the transparent conductive layer 200 may be formed in a structure of two or more layers by combining the above materials. For example, it may be formed as a two-layer structure including a metal layer and a transparent conductive oxide layer to reduce reflectance of incident light and increase transmittance.

The transparent conductive layer 200 may be formed by a method commonly used in the field, for example, a spin coat method, a roller coat method, a bar coat method, a dip coat method, a gravure coat method, or a curtain coat method. coating processes such as coating, die coating, spray coating, doctor coating, and kneader coating; printing processes such as screen printing, spray printing, inkjet printing, iron plate printing, intaglio printing, flat plate printing; and deposition processes such as chemical vapor deposition (CVD), physical vapor deposition (PVD), and plasma enhanced chemical vapor deposition (PECVD).

The liquid crystal layer 300 may change the driving mode of the optical stack by adjusting transmittance of light incident from one or more directions according to an electric field.

The liquid crystal layer 300 may include a liquid crystal compound, and for example, a sealant layer (not shown) provided between the first polarizing plate 100-1 and the second polarizing plate 100-2 in the light control area. not shown) and spacers (not shown).

The liquid crystal compound is not particularly limited as long as it is driven according to an electric field and can control light transmittance, and a conventional or later developed liquid crystal compound may be used. The same can be applied.

In an embodiment, the liquid crystal layer 300 may be driven in a twisted nematic (TN) mode by a liquid crystal compound having a positive dielectric constant anisotropy (Δε> 0). In this case, through the optical design of the polarizer 110, the polarization rotation layer 120-1, and the retardation layer 120-2 described above, the light-blocking property of the optical laminate in the light-blocking mode may be improved.

The sealant may include a curable resin as a base resin. As the base resin, an ultraviolet curable resin or a heat curable resin known to be usable for sealants in the art may be used. The UV curable resin may be a polymer of UV curable monomers. The thermosetting resin may be a polymer of thermosetting monomers.

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 may be used. In one embodiment, the base resin may be an acrylate-based resin, and the acrylate-based resin may be a polymer of acrylic monomers. The acrylic monomer may be, for example, a multifunctional acrylate. In another embodiment, the sealant may further include a monomer component in the base resin. The monomer component may be, for example, a monofunctional acrylate. In the present specification, monofunctional acrylate may mean a compound having one acryl group, and multifunctional acrylate may mean a compound having two or more acryl groups. The curable resin may be cured by UV irradiation and/or heating. The ultraviolet irradiation conditions or heating conditions may be appropriately performed within a range that does not impair the purpose of the present application. The sealant may further include an initiator, for example, a photoinitiator or a thermal initiator, if necessary.

The sealant may be formed by a method commonly used in the related art, and may be formed, for example, by drawing the sealant on the outside of the liquid crystal layer (ie, the inactive area) using a dispenser equipped with a nozzle. there is.

The 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 preferably has a diameter of 1 to 10 μm. In addition, when viewed in a planar direction, the area occupied by the ball spacer in the liquid crystal layer 300 is 0.01 with respect to the area of the liquid crystal layer 300 in terms of user visibility and transmittance improvement in the light transmission mode. to 10% is preferred.

In one embodiment, the liquid crystal layer 300 may further include an alignment layer 400 as needed (see FIG. 4A ), and for example, the liquid crystal layer 300 including a liquid crystal compound It may be provided in the form of a first alignment layer 400-1 and a second alignment layer 400-2 on both surfaces.

The alignment layer 400 is not particularly limited as long as it is for adding orientation to the liquid crystal compound. For example, the alignment layer 400 may be manufactured by applying and curing an alignment layer coating composition including an alignment polymer, a photopolymerization initiator, and a solvent. The orientation polymer is not particularly limited, but polyacrylate-based resins, polyamic acid resins, polyimide-based resins, polymers containing a cinnamate group, etc. can

The variable transmittance optical laminate of the present invention may further include other members within a range not impairing the object of the present invention, for example, further including an adhesive layer 500 (see FIG. 4B). It may be, and may further include a UV absorbing layer, a hard coating layer, and the like.

The adhesive layer 500 may be formed using an adhesive or a pressure-sensitive adhesive, and preferably has appropriate adhesive strength, transparency and thermal stability so as not to cause peeling or bubbles when handling the optical laminate. .

As the adhesive, a conventional or later developed adhesive may be used, and for example, a photocurable adhesive may be used.

The photocurable adhesive is crosslinked and cured by receiving active energy rays such as ultraviolet rays (UV) and electron beams (EB) to exhibit strong adhesive strength, and may be composed of reactive oligomers, reactive monomers, photopolymerization initiators, and the like.

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

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

The photopolymerization initiator serves to initiate photopolymerization by absorbing light energy to generate radicals or cations, and an appropriate one may be selected and used according to the photopolymerization resin.

The pressure-sensitive adhesive may use conventional or later developed pressure-sensitive adhesives, and in one or more embodiments, acrylic pressure-sensitive adhesives, rubber-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, polyvinyl alcohol-based pressure-sensitive adhesives, polyvinylpyrrolidone-based pressure-sensitive adhesives, poly Acrylamide-based adhesives, cellulose-based adhesives, vinylalkyl ether-based adhesives, and the like can be used. The pressure-sensitive adhesive is not particularly limited as long as it has adhesive strength and viscoelasticity, but may be preferably an acrylic pressure-sensitive adhesive in terms of availability, etc., and includes, for example, a (meth)acrylate copolymer, a crosslinking agent, and a solvent. it may be

The crosslinking agent may use conventional or later developed crosslinking agents, and may include, for example, polyisocyanate compounds, epoxy resins, melamine resins, urea resins, dialdehydes, methylol polymers, etc., preferably. It may contain a polyisocyanate compound.

The solvent may include a common solvent used in the resin composition field, and examples thereof include alcohol-based 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-based 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; Solvents such as hydrocarbon-based compounds such as hexane, heptane, benzene, toluene, and xylene may be used. These may be used alone or in combination of two or more.

The thickness of the adhesive layer 500 may be appropriately determined depending on the type of resin serving as the adhesive, adhesive strength, and the environment in which the adhesive is used. In one embodiment, the adhesive layer may be 0.01 to 50 μm, preferably 0.05 to 20 μm, more preferably 0.1 to 10 μm, in order to secure sufficient adhesive strength and minimize the thickness of the optical laminate. It may have a thickness of ㎛.

The ultraviolet ray absorbing layer is not particularly limited as long as it is for preventing deterioration of the optical laminate due to ultraviolet rays. For example, salicylic acid-based ultraviolet absorbers (phenyl salicylate, p-tert-butyl salicylate, etc.), benzophenone Paddy-based UV absorbers (2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, etc.), benzotriazole-based UV 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 -(straight chain and branched chain dodecyl)-4-methylphenol, 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.), cyanoacrylic Late-based ultraviolet absorbers (2'-ethylhexyl-2-cyano-3,3-diphenyl acrylate, ethyl-2-cyano-3-(3',4'-methylenedioxyphenyl)-acrylate, etc. ), triazine-based UV absorbers, etc. can be used, and benzotriazole-based UV absorbers or triazine-based UV absorbers are preferred, which have high transparency and have an excellent effect of preventing deterioration of the polarizing plate or transmittance variable layer, and have a more appropriate spectral absorption spectrum. Triazole-based ultraviolet absorbers are particularly preferred. The benzotriazole-based UV absorber may be bis-formed, for example, 6,6'-methylenebis(2-(2H-benzo[d][1,2,3]triazol-2-yl) -4-(2,4,4-trimethylpentan-2-yl)phenol), 6,6'-methylenebis(2-(2H-benzo[d][1,2,3]triazol-2-yl )-4-(2-hydroxyethyl)phenol) and the like.

The hard coating layer is not particularly limited as long as it is for protecting members such as a polarizing plate and a variable transmittance layer from external physical and chemical impacts, and a conventional or later developed hard coating layer may be used.

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

The photocurable compound and the photoinitiator may be those generally used in the art without limitation, and for example, the photocurable compound may be a photopolymerizable monomer, a photopolymerizable oligomer, etc., for example, monofunctional and/or multifunctional. (meth)acrylates are mentioned, and photoinitiators include oxime esters.

The present invention, in addition to the variable transmittance optical laminate, includes a smart window including the same. In addition, the present invention includes a vehicle in which the smart window is applied to at least one or more of a front window, a rear window, a side window, a sunroof window, and an internal partition, and windows and doors for buildings including the smart window.

Hereinafter, specific embodiments of the present invention will be described. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms, only the present embodiments make the disclosure of the present invention complete, and common knowledge in the art to which the present invention pertains. It is provided to completely inform the person who has the scope of the invention, and the present invention is only defined by the scope of the claims.

Examples and Comparative Examples: Fabrication of Optical Laminates

According to Table 1 and FIG. 1 below, optical laminates according to Examples and Comparative Examples in which a liquid crystal layer was provided between two different polarizing plates having absorption axes parallel to each other were manufactured.

At this time, the absorption axis is substantially parallel to the machine direction (MD) of the polarizer, and the orientation axis of the liquid crystal compound included in the liquid crystal layer and the optical axis of the half-wave plate are 0° in the plane direction. means the value indicated by .

division liquid crystal layer half-wave plate
(polarization rotation layer) negative C plate
(phase difference layer) mode bottom
liquid crystal
orientation axis Top
liquid crystal
orientation axis R _in (450)
/R _in (550) R _in optical axis R _th Comparative Example 1 TN 0° 90° One 275 nm 45° not included Example 1 TN 0° 90° One 275 nm 45° 50 nm Example 2 TN 0° 90° One 275 nm 45° 100 nm Example 3 TN 0° 90° One 275 nm 45° 200 nm Example 4 TN 0° 90° One 275 nm 45° 300 nm Comparative Example 2 TN 0° 90° 0.88 280 nm 45° not included Example 5 TN 0° 90° 0.88 280 nm 45° 50 nm Example 6 TN 0° 90° 0.88 280 nm 45° 100 nm Example 7 TN 0° 90° 0.88 280 nm 45° 200 nm Example 8 TN 0° 90° 0.88 280 nm 45° 300 nm

Experimental Example: Transmittance evaluation

With respect to the optical laminates of Examples 1 to 8 and Comparative Examples 1 to 2, the minimum transmittance according to voltage application, measured in the front direction and side direction (diagonal direction; φ = 45 °, θ = 60 °), respectively, and The transmittance in the non-applied state was evaluated and shown in Table 2 below.

division front direction lateral orientation
(Diagonal direction; φ=45°, θ=60°) no voltage applied application of voltage no voltage applied application of voltage Comparative Example 1 36.3% 0.48% 16.3% 7.6% Example 1 36.3% 0.48% 18.5% 4.9% Example 2 36.4% 0.48% 20.4% 2.8% Example 3 36.4% 0.48% 23.0% 1.9% Example 4 36.5% 0.48% 22.1% 7.4% Comparative Example 2 36.6% 0.18% 17.6% 10.9% Example 5 36.6% 0.18% 18.9% 7.6% Example 6 36.7% 0.18% 19.9% 4.6% Example 7 36.8% 0.18% 20.4% 1.4% Example 8 36.8% 0.18% 18.1% 4.5%

Referring to Table 2, the optical stack of Examples 1 to 4 including a polarization rotation layer (R _in (450)/R _in (550) = 1, R _in = 275 nm) and a negative C plate Compared to the optical laminate of Comparative Example 1 having the same laminate structure as the optical laminate of Examples 1 to 4, except that the sieve does not include a negative C plate, the side (diagonal direction) light leakage phenomenon It can be seen that it is further reduced. Specifically, the optical laminates of Examples 1 to 4 have side (diagonal direction) transmittance of 18% or more, more specifically, 18.5% to 23.0% when no voltage is applied, and side (diagonal direction) transmittance when voltage is applied. The optical laminate of Comparative Example 1 having transmittances of less than 18% (16.3%) and greater than 7.5% (7.6%) of less than 7.5%, more specifically, 1.9% to 7.4%, respectively, when voltage is not applied and when voltage is applied. It can be evaluated that the light leakage phenomenon in the side (diagonal direction) compared to the body is further reduced.

In addition, the optical laminates of Examples 5 to 8 including a polarization rotation layer (R _in (450) / R _in (550) = 0.88, R _in = 280 nm) and a negative C plate, the negative C plate It can be seen that the side (diagonal direction) light leakage phenomenon is further reduced compared to the optical laminate of Comparative Example 2 having the same laminate structure as the optical laminate of Examples 5 to 8 except for not including a (negative C plate). can Specifically, the optical laminates of Examples 5 to 8 have side (diagonal direction) transmittance of 18% or more, more specifically, 18.1% to 20.4% when no voltage is applied, and side (diagonal direction) transmittance when voltage is applied. The optical laminate of Comparative Example 2 having transmittances of less than 18% (17.6%) and greater than 8% (10.9%) of less than 8%, more specifically, from 1.4% to 7.6%, when no voltage is applied and when voltage is applied, respectively. It can be evaluated that the light leakage phenomenon in the side (diagonal direction) compared to the body is further reduced.

Therefore, the variable transmittance optical laminate of the present invention including a polarization rotation layer having reverse wavelength or flat wavelength dispersion characteristics and a negative C plate has excellent light blocking properties in the light blocking mode, particularly in the side (diagonal direction) It can be seen that the light leakage phenomenon is further reduced.

Claims (22)

a first polarizer comprising a first polarizer and a polarization rotation layer;
a first transparent conductive layer formed on one surface of the first polarizing plate;
a second polarizing plate including a second polarizer and a retardation layer and facing the first polarizing plate;
a second transparent conductive layer formed on one surface of the second polarizing plate and facing the first transparent conductive layer; and
A liquid crystal layer provided between the first transparent conductive layer and the second transparent conductive layer,
At least one transparent conductive layer of the first transparent conductive layer and the second transparent conductive layer is formed in direct contact with any one of the first polarizing plate and the second polarizing plate,
The polarization rotation layer has reverse wavelength or flat wavelength dispersion characteristics,
The retardation layer includes a negative C plate (negative C plate), the transmittance variable optical laminate.
The variable transmittance optical stack according to claim 1, wherein the polarization rotation layer is provided on an inner side with respect to the first polarizer.
The method according to claim 1, wherein the polarization rotating layer, the ratio of the in-plane retardation value (R _in (450)) at a wavelength of 450 nm to the in-plane retardation value (R _in (550)) at a wavelength of 550 nm (R _in (450) ) / R _in (550)) of 0.75 to 1.0, the transmittance variable optical laminate.
The variable transmittance optical stack according to claim 1, wherein the polarization rotation layer includes a single-layer or multi-layer half-wave plate.
The method according to claim 4, wherein the in-plane retardation value (R _in ) of the half-wave plate is, 250 to 300nm, the variable transmittance optical laminate.
The method according to claim 1, wherein the retardation layer is provided on the inner side relative to the second polarizer, the variable transmittance optical stack.
The method according to claim 1, wherein the thickness direction retardation value (R _th ) of the retardation layer is, 10 to 500nm, the variable transmittance optical laminate.
The variable transmittance optical stack according to claim 1, wherein an absorption axis of the first polarizer and an absorption axis of the second polarizer are parallel to each other.
The method according to claim 1, wherein the liquid crystal layer, TN (Twisted Nematic) mode, the transmittance variable optical laminate.
The method according to claim 1, wherein at least one transparent conductive layer of the first transparent conductive layer and the second transparent conductive layer does not include a separate substrate between any one of the first polarizing plate and the second polarizing plate. , Transmittance variable optical laminate formed by direct contact.
The method according to claim 1, wherein at least one transparent conductive layer of the first transparent conductive layer and the second transparent conductive layer includes an easy-adhesion layer between the first polarizing plate and any one of the second polarizing plates, An optical laminate with variable transmittance formed by direct contact.
The method according to claim 1, wherein at least one transparent conductive layer of the first transparent conductive layer and the second transparent conductive layer is selected from the group consisting of transparent conductive oxides, metals, carbon-based materials, conductive polymers, conductive inks, and nanowires. Transmittance variable optical laminate comprising the above.
The method according to claim 1, wherein at least one polarizing plate of the first polarizing plate and the second polarizing plate, comprising at least one functional layer selected from the group consisting of a protective layer and a refractive index control layer, the variable transmittance optical laminate.
The method according to claim 1, wherein at least one of the first polarizing plate and the second polarizing plate has a thickness of 30 to 200㎛, the variable transmittance optical laminate.
The method according to claim 1, wherein the liquid crystal layer, a ball spacer (Ball spacer) and a column spacer (Column spacer) comprising at least one member selected from the group consisting of, the variable transmittance optical laminate.
The method according to claim 15, wherein the ball spacer (Ball spacer) has a diameter of 1 to 10㎛, the variable transmittance optical laminate.
The method according to claim 15, The area occupied by the ball spacer in the liquid crystal layer is 0.01% to 10% of the area of the liquid crystal layer, the variable transmittance optical laminate.
The method according to claim 1, wherein the variable transmittance optical laminate, alignment film, point adhesive layer, UV absorbing layer and hard coating layer further comprises at least one member selected from the group consisting of, variable transmittance optical laminate.
Claims 1 to 18 of any one of the manufacturing method of the variable transmittance optical laminate.
A smart window comprising the variable transmittance optical laminate of any one of claims 1 to 18.
An automobile in which the smart window of claim 20 is applied to at least one of a front window, a rear window, a side window, a sunroof window, and an interior partition.
A window for a building comprising the smart window of claim 20.

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