Optical Devices

Abstract

The present application relates to an optical device, the optical device of the present application comprising a first outer substrate, a liquid crystal cell and a second outer substrate in that order, the liquid crystal cell comprising an upper substrate including a first base layer and an adhesive layer, a lower substrate including a second base layer and a spacer, and a liquid crystal layer including a liquid crystal compound between the upper substrate and the lower substrate, further comprising a first intermediate layer between the first outer substrate and the liquid crystal cell and a second intermediate layer between the second outer substrate and the liquid crystal cell, the cell gap of the liquid crystal cell being properly maintained, the upper substrate and the lower substrate having excellent adhesion, and the liquid crystal cell being pressed and overflowing phenomenon can be solved when the outer substrates are bonded.

Description

[Technical field]

[0001] The present application relates to optical devices.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0039633 dated March 30, 2022, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference. [Background technology]

[0003] For the long-term stability and large-area scalability of a liquid crystal film cell using a flexible substrate, it is important to maintain a cell gap between the upper and lower substrates and to provide adhesive strength between the upper and lower substrates.

[0004] Non-Patent Document 1 ("Tight Bonding of Two Plastic Substrates for Flexible LCDs" SID Symposium Digest, 38, pp.653-656 (2007)) discloses a technique of forming a pillar or wall-shaped organic film pattern of the cell gap height on one substrate and fixing it to the opposite substrate using an adhesive. However, this technique requires that the adhesive be located only on the pillar or wall surface, and the technique of micro-stamping the adhesive on the pillar or wall surface is highly difficult to process, difficult to control the thickness and area of ​​the adhesive, and there is a high possibility that the adhesive will be pushed out when the upper and lower substrates are bonded, which may contaminate the alignment film or liquid crystal. Summary of the Invention [Problem to be solved by the invention]

[0005] In order to maintain the cell gap of the liquid crystal cell and ensure the adhesion between the upper and lower substrates, it is possible to consider forming a spacer and an alignment film on the lower substrate, and then forming an adhesive layer having both liquid crystal alignment and adhesion on the upper substrate, followed by bonding. However, during the autoclave process for bonding glass substrates to both sides of the liquid crystal cell, the outer layer surrounding the sides of the liquid crystal cell has a low storage modulus at high temperatures, so strong pressure may be applied to the edge region of the liquid crystal cell adjacent to the outer layer. Therefore, the edge region of the liquid crystal cell may experience a collapse (pressure) of the cell gap and an overflow of liquid crystal during bonding of the outer substrates due to uneven pressure being concentrated in a local area.

[0006] The objective of the present application is to provide an optical device in which the cell gap of a liquid crystal cell is properly maintained, the upper and lower substrates have excellent adhesion, and the liquid crystal cell is prevented from being pressed and overflowed when it is attached to an outer substrate. [Means for solving the problem]

[0007] In the present specification, when the measurement temperature affects the results of a physical property, the relevant physical property is a physical property measured at room temperature, unless otherwise specified. The term room temperature refers to a natural temperature without heating or cooling, and is usually a temperature within a range of about 10°C to 30°C, or about 23°C or about 25°C. Furthermore, unless otherwise specified in the present specification, the unit of temperature is °C. In the present specification, when the measurement pressure affects the results of a physical property, the relevant physical property is a physical property measured at normal pressure, unless otherwise specified. The term normal pressure refers to a natural pressure without heating or cooling, and usually refers to about 1 atmosphere.

[0008] This application relates to an optical device. FIG. 1 exemplarily illustrates the optical device of this application. The upper structure of FIG. 1 exemplarily illustrates the top surface of the optical device, and the lower structure of FIG. 1 exemplarily illustrates the side surface of the optical device. The top surface and side surface of the optical device are based on a state in which the second outer substrate of the optical device is placed on the bottom. Therefore, the top surface of the optical device may refer to the structure seen from the first outer substrate side.

[0009] As shown in FIG. 1, the optical device of the present application may include a first outer substrate 101, a liquid crystal cell 200, and a second outer substrate 102, in that order. The liquid crystal cell may include an upper substrate, a lower substrate, and a liquid crystal layer between the upper substrate and the lower substrate. The upper substrate may include a first base layer and an adhesive layer. The lower substrate may include a second base layer and a spacer. The liquid crystal layer may include a liquid crystal compound. The first base layer may be disposed closer to the first outer substrate than the second base layer, and the second base layer may be disposed closer to the second outer substrate than the first base layer.

[0010] The optical device may include a first intermediate layer 301 disposed between the liquid crystal cell 200 and the first outer substrate 101. The optical device may include a second intermediate layer 302 disposed between the liquid crystal cell 200 and the second outer substrate 102.

[0011] The optical device may include at least one region satisfying the following formula 1. Through this, local pressure applied to the edge of the liquid crystal cell during the process of bonding the liquid crystal cell and the outer substrate can be dispersed, and the phenomenon of the liquid crystal cell being pressed and overflowing can be solved.

[0012] [Formula 1]

[0013] 20mm≦L1-L2

[0014] In Equation 1, L1 is the distance between the outer periphery of the first outer substrate and the outer periphery of the liquid crystal cell or the distance between the second outer substrate and the outer periphery of the liquid crystal cell, and L2 is the distance between the outer periphery of the first outer substrate and the outer periphery of the first intermediate layer or the distance between the outer periphery of the second outer substrate and the outer periphery of the second intermediate layer.

[0015] In one embodiment, L1 may be the distance between the outer periphery of the first outer substrate and the outer periphery of the liquid crystal cell, and L2 may be the distance between the outer periphery of the first outer substrate and the outer periphery of the first intermediate layer. In another embodiment, L1 may be the distance between the outer periphery of the second outer substrate and the outer periphery of the liquid crystal cell, and L2 may be the distance between the outer periphery of the second outer substrate and the outer periphery of the second intermediate layer. In one embodiment, the difference between the distance L1 between the outer periphery of the first outer substrate and the outer periphery of the liquid crystal cell and the distance L2 between the outer periphery of the first outer substrate and the outer periphery of the first intermediate layer (D1=L1-L2 for the first outer substrate) may be 20 mm or more, and at the same time, the difference between the distance L1 between the outer periphery of the second outer substrate and the outer periphery of the liquid crystal cell and the distance L2 between the outer periphery of the second outer substrate and the outer periphery of the second intermediate layer (D2=L1-L2 for the second outer substrate) may be 20 mm or more. The distance between the outer periphery of the first outer substrate and the outer periphery of the liquid crystal cell may refer to the distance between the first outer substrate and the outer periphery of the first base layer of the liquid crystal cell, and the distance between the outer periphery of the second outer substrate and the outer periphery of the liquid crystal cell may refer to the distance between the second outer substrate and the outer periphery of the second base layer of the liquid crystal cell.

[0016] In the formula 1, L1 may mean the shortest linear distance between the outer periphery of the first outer substrate and the outer periphery of the liquid crystal cell, or the shortest linear distance between the outer periphery of the second outer substrate and the outer periphery of the liquid crystal cell. Specifically, L1 may mean the shortest distance when a straight line is connected between any point on the outer periphery of the first outer substrate or the second outer substrate and any point on the outer periphery of the liquid crystal cell. In the formula 1, L2 may mean the shortest linear distance between the outer periphery of the first outer substrate and the outer periphery of the first intermediate layer, or the shortest linear distance between the outer periphery of the second outer substrate and the outer periphery of the second intermediate layer. Specifically, L2 may mean the shortest distance when a straight line is connected between any point on the outer periphery of the first outer substrate and any point on the outer periphery of the first intermediate layer. Or, L2 may mean the shortest distance when a straight line is connected between any point on the outer periphery of the second outer substrate and any point on the outer periphery of the second intermediate layer.

[0017] In one example, the first outer substrate, the second outer substrate, the liquid crystal cell, the first intermediate layer, and the second intermediate layer may all be laminated so that their longitudinal directions are parallel to each other and their width directions are parallel to each other. The first outer substrate, the second outer substrate, the liquid crystal cell, the first intermediate layer, and the second intermediate layer may each have a substantially quadrangular, e.g., rectangular, shape, and the longitudinal direction may mean a direction parallel to the longest side of the quadrangle, and the width direction may mean a direction parallel to the shortest side of the quadrangle. In this specification, "parallel" may mean that the directions, axes, or sides to be evaluated are mutually at approximately 0 degrees to 10 degrees, 0 degrees to 5 degrees, 0 degrees to 3 degrees, or approximately 0 degrees. In this specification, a rectangle may mean a shape in which the angles of the four vertices are approximately 80 degrees to 100 degrees, 85 degrees to 95 degrees, 93 degrees to 91 degrees, or approximately 90 degrees.

[0018] In defining L1 and L2 in Equation 1, the "straight line" may be parallel to the longitudinal direction (x-axis in FIG. 1) or the width direction (y-axis in FIG. 1). In one example, when the optical device is observed in the normal direction and the longitudinal direction of the optical device is placed at the top and bottom and the width direction is placed at the left and right, if the region satisfying Equation 1 exists at the left and right sides of the liquid crystal cell, the straight line may be parallel to the longitudinal direction of the optical device. In another example, when observed as above, if the region satisfying Equation 1 exists at the top and bottom of the liquid crystal cell, the straight line may be parallel to the width direction of the optical device. In this specification, the normal direction of the optical device may mean the lamination direction of each component of the optical device or the thickness direction of the optical device, or may mean a direction perpendicular to the plane of the first outer substrate, the second outer substrate, the liquid crystal cell, the first intermediate layer, and / or the second intermediate layer.

[0019] In an optical device, the region satisfying the formula 1 may exist over one side of a liquid crystal cell. When there is one region satisfying the formula 1, all of the regions over at least one side of the liquid crystal cell may satisfy the formula 1. For example, when there are n regions satisfying the formula 1, all of the regions over at least n sides of the liquid crystal cell may satisfy the formula 1.

[0020] In one example, when the optical device includes one region satisfying the formula 1, the region may be present on any one of the left side, right side, upper side, and lower side of the liquid crystal cell. In this case, the remaining three regions may not satisfy the formula 1. In another example, when the optical device includes two or more regions satisfying the formula 1, for example, when the optical device includes two regions, the regions may be present on both sides of the liquid crystal cell, for example, on the left and right sides, or on the upper and lower sides. In this case, the remaining two regions may not satisfy the formula 1. FIG. 1 exemplarily illustrates a case where the regions are present on the left and right sides of the liquid crystal cell, respectively (D1 and D2). According to one embodiment of the present application, the regions satisfying the formula 1 may be present on the left and right sides of the liquid crystal cell, respectively. In another example, when the optical device includes three or more regions satisfying the formula 1, the regions may be connected to each other.

[0021] When the optical device includes a region not satisfying Formula 1, the L1-L2 value of Formula 1 in the region may be less than 20 mm, less than 10 mm, less than 5 mm, less than 1 mm, or approximately 0 mm. In one example, in the region, there may be substantially no distance between the outer edge of the liquid crystal cell and the outer edge of the first intermediate layer and / or the second intermediate layer.

[0022] The distance defined as L1-L2 in Equation 1 may be 20 mm or more, 25 mm or more, or 30 mm or more. The upper limit of the distance defined as L1-L2 in Equation 1 may be, for example, 200 mm or less, 180 mm or less, 160 mm or less, 140 mm or less, 120 mm or less, 100 mm or less, 80 mm or less, 60 mm or less, or 40 mm or less. If the distance L1-L2 is too long, the active area in which the liquid crystal is driven may be significantly reduced, so it may be appropriate for the upper limit to be within the above range. L1 and L2 may be appropriately selected according to the shape and design of the product to be actually applied, within a range that does not impair the object of the present application.

[0023] When the optical device is observed in a normal direction, the distance between the outer periphery of the first outer substrate and the outer periphery of the second outer substrate may be less than 5 mm, less than 3 mm, less than 1 mm, or approximately 0 mm. The distance may refer to the shortest distance when a straight line is drawn between any point on the outer periphery of the first outer substrate and any point on the outer periphery of the second outer substrate. In this case, the distance may be less than 5 mm, less than 3 mm, less than 1 mm, or approximately 0 mm in all the outer peripheries of the first outer substrate and the second outer substrate. That is, when the optical device is observed in a normal direction, the area of ​​the first outer substrate and the area of ​​the second outer substrate may be approximately the same.

[0024] When the optical device is observed in the normal direction, the distance between the outer periphery of the first intermediate layer and the outer periphery of the second intermediate layer may be less than 5 mm, less than 3 mm, less than 1 mm, or approximately 0 mm. The distance may refer to the shortest distance when a straight line is drawn between any point on the outer periphery of the first intermediate layer and any point on the outer periphery of the second intermediate layer. In this case, the distance may be less than 5 mm, less than 3 mm, less than 1 mm, or approximately 0 mm for all of the outer peripheries of the first intermediate layer and the second intermediate layer. That is, when the optical device is observed in the normal direction, the area of ​​the first intermediate layer and the area of ​​the second intermediate layer may be approximately the same.

[0025] In one embodiment, the area of ​​the first intermediate layer (unit: mm 2 ) and / or the area of ​​the second intermediate layer (unit: mm 2 ) is the area of ​​the liquid crystal cell (unit: mm 2 ) The area of ​​the liquid crystal cell may be the area of ​​the first substrate layer and / or the area of ​​the second substrate layer. In one example, when the optical device is observed in the normal direction, the area of ​​the liquid crystal cell may be included in the area of ​​the first intermediate layer and / or the area of ​​the second intermediate layer. This can distribute local pressure applied to the edge of the liquid crystal cell during the bonding process with the outer substrate, and can solve the phenomenon of the liquid crystal cell being squeezed and overflowing.

[0026] In one example, when the optical device is viewed in the normal direction, the first intermediate layer may be located at the center of the first outer substrate, and the liquid crystal cell (or the first base layer) may be located at the center of the first intermediate layer, and when the optical device is viewed in the normal direction, the second intermediate layer may be located at the center of the second outer substrate, and the liquid crystal cell (or the second base layer) may be located at the center of the second intermediate layer.

[0027] In one example, the horizontal and vertical area of ​​the liquid crystal cell can be appropriately selected depending on the intended use of the optical device. For example, the horizontal length of the liquid crystal cell can be in the range of 100 mm to 5000 mm, and the vertical length can be in the range of 100 mm to 5000 mm.

[0028] The first and second intermediate layers can each be a polarizer or a polymer film.

[0029] In one example, the first intermediate layer and the second intermediate layer may each be a polarizer. The polarizer in the first intermediate layer may be referred to as a first polarizer, and the polarizer in the second intermediate layer may be referred to as a second polarizer.

[0030] The term "polarizer" as used herein means a film, sheet, or element having a polarizing function. A polarizer is a functional element that can extract light vibrating in one direction from incident light vibrating in various directions.

[0031] The first polarizer and the second polarizer may be an absorptive polarizer or a reflective polarizer, respectively. In this specification, the absorptive polarizer refers to an element that exhibits selective transmission and absorption characteristics for incident light. For example, the absorptive polarizer can transmit light that vibrates in one direction from incident light that vibrates in various directions, and absorb light that vibrates in the remaining directions. In this specification, the reflective polarizer refers to an element that exhibits selective transmission and reflection characteristics for incident light. For example, the reflective polarizer can transmit light that vibrates in one direction from incident light that vibrates in various directions, and reflect light that vibrates in the remaining directions. According to one embodiment of the present application, the polarizer may be an absorptive polarizer.

[0032] The first polarizer and the second polarizer may each be a linear polarizer. In this specification, a linear polarizer means that selectively transmitted light is linearly polarized light that vibrates in one direction, and selectively absorbed or reflected light is linearly polarized light that vibrates in a direction perpendicular to the vibration direction of the linearly polarized light. In the case of an absorptive linear polarizer, the light transmission axis and the light absorption axis may be perpendicular to each other. In the case of a reflective linear polarizer, the light transmission axis and the light reflection axis may be perpendicular to each other.

[0033] In one example, the first polarizer and the second polarizer may each be a polymer stretched film dyed with iodine or an anisotropic dye. An example of the polymer stretched film is a PVA (poly(vinyl alcohol)) stretched film. In another example, the first polarizer and the second polarizer may each be a guest-host type polarizer having a liquid crystal polymerized in an oriented state as a host and an anisotropic dye aligned by the orientation of the liquid crystal as a guest. In another example, the first polarizer and the second polarizer may each be a thermotropic liquid crystal film or a lyotropic liquid crystal film.

[0034] A protective film, an anti-reflection film, a retardation film, an adhesive layer, an adhesive layer, a surface treatment layer, etc. may be additionally formed on one or both sides of the first polarizer and the second polarizer. For example, a thermoplastic resin having excellent transparency, mechanical strength, thermal stability, moisture blocking property, or isotropy may be used as the material of the protective film. Examples of such resins include cellulose resins such as TAC (triacetyl cellulose), polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, cyclic polyolefin resins such as norbornene resins, polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. The retardation film may be, for example, a ¼ wavelength plate or a ½ wavelength plate. The ¼ wavelength plate may have an in-plane retardation value within a range of about 100 nm to 180 nm, 100 nm, or 150 nm for light with a wavelength of 550 nm. The half wave plate may have an in-plane retardation value within a range of about 200 nm to 300 nm or 250 nm to 300 nm for light with a wavelength of 550 nm. The retardation film may be, for example, a polymer stretched film or a liquid crystal polymerized film.

[0035] The transmittance of the first polarizer and the second polarizer for light with a wavelength of 550 nm may be within a range of 40% to 50%, respectively. The transmittance may refer to the single transmittance of the polarizer for light with a wavelength of 550 nm. The single transmittance of the polarizer may be measured, for example, using a spectrometer (V7100, manufactured by Jasco). For example, the air may be set as the baseline while the polarizer sample (without the upper and lower protective films) is placed in the instrument, and the axis of the polarizer sample may be aligned vertically and horizontally with the axis of the reference polarizer to measure the transmittance of each, and then the single transmittance may be calculated.

[0036] When the first and second intermediate layers each include a polarizer, the polarizer may have a thickness in the range of 1 μm to 500 μm. Specifically, the polarizer may have a thickness of 30 μm or more, 50 μm or more, 70 μm or more, or 90 μm or more, and may have a thickness of 400 μm or less, 300 μm or less, 200 μm or less, or 100 μm or less.

[0037] In one example, the first intermediate layer and the second intermediate layer may each be a polymer film. The polymer film may not have a polarizing function. Therefore, the polymer film may not contain iodine, anisotropic dye, or dichroic dye. In one example, the first intermediate layer and the second intermediate layer may each be a single-layer structure of a polymer film or a laminate of polymer films. The laminate of polymer films may mean a structure in which two or more polymer films are laminated. In one example, the polymer film may include at least one selected from the group consisting of a triacetyl cellulose (TAC) film, a diacetyl cellulose (DAC) film, a cycloolefin copolymer (COP) film, a polyacrylate (PA) film, a poly(methyl methacrylate) film (PMMA), a polycarbonate (PC) film, a polyethylene (PE) film, a polypropylene (PP) film, a polyvinyl alcohol (PVA) film, a polyimide (PI) film, a polysulfone (PSF) film, a polyphenylsulfone (PPS) film, a polyethersulfone (PES) film, a polyetheretherketon (PEEK) film, a polyetherimide (PEI) film, a polyethylenenaphthalate (PEN) film, and a polyethyleneterephtalate (PET) film.

[0038] When the first and second intermediate layers are each a polymer film, the thickness of the polymer film may be within the range of 10 μm to 1,000 μm. Specifically, the thickness of the polymer film may be 30 μm or more, 50 μm or more, 70 μm or more, 90 μm or more, or 110 μm or more, and may be 1,000 μm or less, 800 μm or less, 600 μm or less, 400 μm or less, or 200 μm or less. When the first and second intermediate layers are each a laminate of polymer films, the thickness of the entire laminate may be within the above range.

[0039] The first outer substrate and the second outer substrate may be an inorganic substrate or a polymer substrate, independently. The inorganic substrate is not particularly limited, and a known inorganic substrate may be used. For example, the inorganic substrate may be a glass substrate having excellent light transmittance. The glass substrate may be, but is not limited to, a soda lime glass substrate, a general reinforced glass substrate, a borosilicate glass substrate, or an alkali-free glass substrate. The polymer substrate may be a cellulose film such as TAC (triacetyl cellulose) or DAC (diacetyl cellulose); a COP (cycloolefin copolymer) film such as a norbornene derivative; an acrylic film such as PAR (Polyacrylate) or PMMA (poly(methyl methacrylate); a PC (polycarbonate) film; a polyolefin film such as PE (polyethylene) or PP (polypropylene); a PVA (polyvinyl Examples of the materials that can be used include, but are not limited to, sulfone-based films such as polysulfone (PSF) films, polyphenylsulfone (PPS) films, and polyethersulfone (PES) films; polyetheretherketon (PEEK) films; polyetherimide (PEI) films; polyester-based films such as polyethylenenaphthalate (PEN) films and polyethyleneterephtalate (PET) films; and fluororesin films. The first and second outer substrates may each have a functional layer such as a coating layer of gold, silver, or a silicon compound such as silicon dioxide or silicon monoxide, or an anti-reflection layer, as required.

[0040] In one embodiment, the first outer substrate and / or the second outer substrate may be a glass substrate, and the area of ​​the first outer substrate and / or the second outer substrate may be larger than the area of ​​the first intermediate layer and / or the second intermediate layer.

[0041] The thickness of each of the first and second outer substrates may be about 0.3 mm or more. In other examples, the thickness may be about 0.5 mm or more, 1 mm or more, 1.5 mm or more, or about 2 mm or more, and may be about 10 mm or less, 9 mm or less, 8 mm or less, 7 mm or less, 6 mm or less, 5 mm or less, 4 mm or less, or about 3 mm or less.

[0042] The first outer substrate and the second outer substrate may be flat or curved. For example, the first outer substrate and the second outer substrate may be flat or curved, or one of them may be flat and the other curved. If both of them are curved, their curvatures or radii of curvature may be the same or different. In this specification, the curvature or radii of curvature may be measured by a method known in the art, for example, using a non-contact device such as a 2D Profile Laser Sensor, a Chromatic Confocal Line Sensor, or a 3D Measuring Confocal Microscopy. Methods for measuring the curvature or radii of curvature using such devices are well known.

[0043] The horizontal and vertical lengths of the first outer substrate and / or the second outer substrate may be appropriately selected in consideration of the optical device to which it is applied. In one embodiment, the horizontal length of the first outer substrate and / or the second outer substrate may be 50 mm or more, 100 mm or more, 150 mm or more, or 180 mm or more larger than the horizontal length of the liquid crystal cell. In one embodiment, the vertical length of the first outer substrate and / or the second outer substrate may be 50 mm or more, 100 mm or more, 150 mm or more, or 180 mm or more larger than the vertical length of the liquid crystal cell. The difference between the horizontal length of the first outer substrate and / or the second outer substrate and the horizontal length of the liquid crystal cell may be, for example, 5,000 mm or less, 4,000 mm or less, 3,000 mm or less, 2,000 mm or less, 1,000 mm or less, or 500 mm or less. The difference between the vertical length of the first outer substrate and / or the second outer substrate and the vertical length of the liquid crystal cell may be, for example, 5,000 mm or less, 4,000 mm or less, 3,000 mm or less, 2,000 mm or less, 1,000 mm or less, or 500 mm or less.

[0044] In one example, the optical device may satisfy the following Equation 2. This may be advantageous in dispersing local pressure applied to the edge of the liquid crystal cell during bonding with the outer substrate, thereby solving the phenomenon of squeezing and overflowing the liquid crystal cell.

[0045] [Formula 2]

[0046] A1 <A2<A3

[0047] In formula 2, A1 is the area of ​​the liquid crystal cell (unit: mm 2 ), and A2 is the area of ​​the first intermediate layer and / or the second intermediate layer (unit: mm 2 ), and A3 is the area of ​​the first outer substrate and / or the second outer substrate (unit: mm 2 ).

[0048] The optical device may further include at least one adhesive layer located between the first outer substrate and the liquid crystal cell and between the second outer substrate and the liquid crystal cell.

[0049] In one example, the optical device may further include a first adhesive layer 401 between the first outer substrate 101 and the first intermediate layer 301, a second adhesive layer 402 between the first intermediate layer 301 and the liquid crystal cell 200, a third adhesive layer 403 between the liquid crystal cell 200 and the second intermediate layer 302, and a fourth adhesive layer 404 between the second intermediate layer 302 and the second outer substrate 102. One side of the first adhesive layer may be in direct contact with the first outer substrate, and the other side may be in direct contact with the first intermediate layer. One side of the second adhesive layer may be in direct contact with the first intermediate layer, and the other side may be in direct contact with the liquid crystal cell. One side of the third adhesive layer may be in direct contact with the liquid crystal cell, and the other side may be in direct contact with the second intermediate layer. One side of the fourth adhesive layer may be in direct contact with the second intermediate layer, and the other side may be in direct contact with the second outer substrate. In this specification, A being in direct contact with B may mean that A and B are in direct contact with each other without any intermediate therebetween.

[0050] When the optical device is observed in a normal direction, the area of ​​the first intermediate layer may be included in the area of ​​the first outer substrate, and the area of ​​the second intermediate layer may be included in the area of ​​the second outer substrate. When the optical device is observed in a normal direction, the areas of the first outer substrate and the second outer substrate may be substantially the same. When the optical device is observed in a normal direction, the area of ​​the first intermediate layer may be substantially the same as the area of ​​the first outer substrate and / or the second outer substrate. Furthermore, the area of ​​the first adhesive layer, the second adhesive layer, the third adhesive layer and / or the fourth adhesive layer may be substantially the same as the area of ​​the first outer substrate and / or the second outer substrate.

[0051] In one example, the storage modulus of the first adhesive layer, the second adhesive layer, the third adhesive layer, and / or the fourth adhesive layer may be higher than the storage modulus of the adhesive layer included in the liquid crystal cell. Also, the loss modulus of the first adhesive layer, the second adhesive layer, the third adhesive layer, and / or the fourth adhesive layer may be higher than the loss modulus of the adhesive layer included in the liquid crystal cell. If the storage modulus or loss modulus of the first adhesive layer, the second adhesive layer, the third adhesive layer, and / or the fourth adhesive layer is higher than the storage modulus or loss modulus of the adhesive layer, it may be advantageous to reduce appearance defects even under durable conditions.

[0052] In one example, the storage modulus of the first adhesive layer, the second adhesive layer, the third adhesive layer and / or the fourth adhesive layer at a temperature of 25°C and a frequency of 1 Hz may be in the range of 1 MPa to 100 MPa. The storage modulus may be, specifically, 3 MPa or more, and 80 MPa or less, 60 MPa or less, 40 MPa or less, 20 MPa or less, or 10 MPa or less. In one example, the loss modulus of the first adhesive layer, the second adhesive layer, the third adhesive layer and / or the fourth adhesive layer at a temperature of 25°C and a frequency of 1 Hz may be, specifically, 1 MPa or more, and 80 MPa or less, 60 MPa or less, 40 MPa or less, 20 MPa or less, or 10 MPa or less. The storage modulus of the first adhesive layer, the second adhesive layer, the third adhesive layer and / or the fourth adhesive layer may each have a higher value than the loss modulus.

[0053] As an example, the first adhesive layer, the second adhesive layer, the third adhesive layer, and / or the fourth adhesive layer may have a Young's modulus (E) in the range of 0.1 MPa to 100 MPa. As another example, the Young's modulus (E) of the first adhesive layer, the second adhesive layer, the third adhesive layer, and / or the fourth adhesive layer may be 0.2 MPa or more, 0.4 MPa or more, 0.6 MPa or more, 0.8 MPa or more, 1 MPa or more, 5 MPa or more, or about 10 MPa or more, and may be about 95 MPa or less, 80 MPa or less, 75 MPa or less, 70 MPa or less, 65 MPa or less, 60 MPa or less, 55 MPa or less, or about 50 MPa or less. The Young's modulus (E) may be measured, for example, by a method specified in ASTM D882, and may be measured by cutting the film into a shape provided in the corresponding standard and using equipment capable of measuring a stress-strain curve (capable of simultaneously measuring force and length), for example, a universal testing machine (UTM). When the Young's modulus of the adhesive layer included in the optical device is within the above range, it may be more advantageous to ensure excellent durability of the optical device. When the adhesive layer is a laminate of at least two or more sub-adhesive layers, each of the sub-intermediate layers may satisfy the above Young's modulus range.

[0054] As one example, the first adhesive layer, the second adhesive layer, the third adhesive layer, and / or the fourth adhesive layer may each have a thermal expansion coefficient of 2,000 ppm / K or less. In other examples, the thermal expansion coefficient may be about 1,900 ppm / K or less, 1,700 ppm / K or less, 1,600 ppm / K or less, or about 1,500 ppm / K or less, or about 10 ppm / K or more, 20 ppm / K or more, 30 ppm / K or more, 40 ppm / K or more, 50 ppm / K or more, 60 ppm / K or more, 70 ppm / K or more, 80 ppm / K or more, 90 ppm / K or more, 100 ppm / K or more, 200 ppm / K or more, 300 ppm / K or more, 400 ppm / K or more, 500 ppm / K or more, 600 ppm / K or more, 700 ppm / K or more, or about 800 ppm / K or more. The thermal expansion coefficient of the adhesive layer can be measured, for example, according to the ASTM D696 standard, by cutting into a shape specified in the relevant standard and measuring the change in length per unit temperature to calculate the thermal expansion coefficient, or by a known method such as TMA (ThermoMechanic Analysis). If the thermal expansion coefficient of the adhesive layer included in the optical device is within the above range, it may be more advantageous to ensure excellent durability of the optical device. If the adhesive layer is a laminate of at least two or more sub-adhesive layers, each of the sub-adhesive layers may satisfy the above range of thermal expansion coefficient.

[0055] The first adhesive layer, the second adhesive layer, the third adhesive layer and / or the fourth adhesive layer may be a thermoplastic polyurethane (TPU) adhesive layer, a polyamide adhesive layer, a polyester adhesive layer, an EVA (Ethylene Vinyl Acetate) adhesive layer, an acrylic adhesive layer, a silicone adhesive layer or a polyolefin adhesive layer. According to one embodiment of the present application, the first adhesive layer, the second adhesive layer, the third adhesive layer and the fourth adhesive layer may be a thermoplastic polyurethane adhesive layer.

[0056] As an example, the sum of the total thicknesses of the adhesive layers included in the optical device may be 200 μm or more. The sum of the total thicknesses of the adhesive layers may mean the sum of the thicknesses of all the adhesive layers included in the optical device, for example, the first, second, third and fourth adhesive layers. When the total thickness of the adhesive layers is within the above range, it may be advantageous to ensure the structural stability and uniform appearance characteristics of the optical device by minimizing defects during the bonding process of the outer substrate. Specifically, the sum of the total thicknesses of the adhesive layers may be 1,500 μm or more, about 1,650 μm or more, 1,700 μm or more, 1,750 μm or more, 1,800 μm or more, 1,850 μm or more, 1,900 μm or more, 1,950 μm or more, 2,000 μm or more, 2,100 μm or more, 2,150 μm or more, or about 2,200 μm or more. The sum of the total thicknesses of the adhesive layers may be, for example, about 6,000 μm or less, 5,900 μm or less, 5,800 μm or less, 5,700 μm or less, 5,600 μm or less, 5,500 μm or less, 5,400 μm or less, 5,300 μm or less, 5,200 μm or less, 5,100 μm or less, or about 5,000 μm or less. If the total thickness of the adhesive layers is excessively thick, it may degrade electro-optical properties such as transmittance properties of the optical device, so it may be advantageous to be within the above range.

[0057] The first adhesive layer, the second adhesive layer, the third adhesive layer and / or the fourth adhesive layer may each have a single layer structure of one adhesive layer or may be a laminate of two or more sub-adhesive layers. The thickness and number of the sub-adhesive layers may be controlled in consideration of the desired thickness of the intermediate layer. In one example, the thickness of one adhesive layer or sub-intermediate layer having a single layer structure may be in the range of 100 μm to 500 μm or 300 μm to 400 μm.

[0058] In one example, when the first intermediate layer and the second intermediate layer include a first polarizer and a second polarizer, respectively, the light transmission axis of the first polarizer and the light transmission axis of the second polarizer may be perpendicular to each other. Specifically, the angle between the light transmission axis of the first polarizer and the light transmission axis of the second polarizer may be within a range of 80 degrees to 100 degrees or 85 degrees to 95 degrees. In this case, the thickness of the second adhesive layer between the first intermediate layer and the liquid crystal cell and the third adhesive layer between the second intermediate layer and the liquid crystal cell may be 380 μm or less. When the light transmission axis of the first polarizer and the light transmission axis of the second polarizer are perpendicular to each other, light leakage may occur due to the distance between the first polarizer and the second polarizer. However, by setting the thickness of the second adhesive layer and the third adhesive layer within the above range, the distance between the first polarizer and the second polarizer can be minimized to reduce light leakage and ensure the structural safety of the liquid crystal cell. The lower limit of the thickness of the second adhesive layer and the third adhesive layer may be 10 μm or more.

[0059] 2 shows an example of a liquid crystal cell. As shown in FIG. 2, the liquid crystal cell may include a first substrate layer 10a, an adhesive layer 10c formed on the inner side of the first substrate layer, a second substrate layer 20a disposed opposite the first substrate layer 10a, a spacer 20c formed on the inner side of the second substrate layer 20a, and a liquid crystal layer 30 disposed between the first substrate layer 10a and the second substrate layer 20a.

[0060] The first and second substrate layers may be, for example, inorganic films such as glass films, crystalline or amorphous silicon films, quartz or ITO (Indium Tin Oxide) films, or polymer films, and a polymer film may be used in terms of implementing a flexible element.

[0061] In one example, the first substrate layer and the second substrate layer may each be a polymer film. Examples of the polymer film include triacetyl cellulose (TAC); cycloolefin copolymer (COP) such as norbornene derivatives; poly(methyl methacrylate) (PMMA); polycarbonate (PC); polyethylene (PE); polypropylene (PP); polyvinyl alcohol (PVA); diacetyl cellulose (DAC); polyacrylate (PAC); polyether sulfone (PES); polyetheretherketon (PEEK); polyphenylsulfone (PPS), polyetherimide (PEI); polyethylenemaphthatlate (PEN); polyethyleneterephtalate (PET); polyimide (PI); polysulfone (PSF); polyarylate (PAR) or amorphous fluororesin, but are not limited thereto. The first substrate layer and the second substrate layer may have a coating layer of gold, silver, silicon dioxide, silicon monoxide or other silicon compound, or an anti-reflection layer, if necessary.

[0062] The first and second substrate layers may each have a thickness of about 10 μm to about 1,000 μm. In another example, the substrate layers may each have a thickness of about 20 μm or more, 40 μm or more, 60 μm or more, 80 μm or more, 100 μm or more, 120 μm or more, 140 μm or more, 160 μm or more, or about 180 μm or more, and may each have a thickness of about 900 μm or less, 800 μm or less, 700 μm or less, 600 μm or less, 500 μm or less, or about 400 μm or less. When the thicknesses of the first and second substrate layers are within the above ranges, defects in appearance such as wrinkles can be reduced when the liquid crystal cell is bonded to an outer substrate to manufacture an optical device.

[0063] The adhesive layer may be present on the inner surface of the first substrate layer. In this specification, the "inner surface" of a component included in a liquid crystal cell may refer to the surface facing the liquid crystal layer.

[0064] In one example, the storage modulus of the pressure-sensitive adhesive layer at 25° C. and 1 Hz frequency may be within the range of 0.2 MPa to 10 MPa. The storage modulus of the pressure-sensitive adhesive layer may be specifically 0.3 MPa or more or 0.5 MPa or more, and 8 MPa or less, 6 MPa or less, 4 MPa or less, or 2 MPa or less. In one example, the loss modulus of the pressure-sensitive adhesive layer at 25° C. and 1 Hz frequency may be within the range of 0.5 MPa to 2 MPa. The loss modulus of the pressure-sensitive adhesive layer may be specifically 0.6 MPa or more, 0.7 MPa or more, or 0.8 MPa or more, and 1.8 MPa or less, 1.6 MPa or less, 1.4 MPa or less, or 1.2 MPa or less. If the modulus of the pressure-sensitive adhesive layer inside the liquid crystal cell is too low, it may be difficult to maintain the cell gap of the liquid crystal cell, and if the modulus of the pressure-sensitive adhesive layer inside the liquid crystal cell is too high, it may be difficult to impart an adhesive effect, so that the modulus may be advantageously within the above range. In one example, the storage modulus of the pressure-sensitive adhesive layer may have a lower value than the loss modulus.

[0065] The pressure-sensitive adhesive layer may be optically transparent, and may have an average transmittance of about 80% or more, 85% or more, 90% or more, or 95% or more in the visible light region, for example, wavelengths of 380 nm to 780 nm.

[0066] The adhesive layer may be a liquid crystal aligning adhesive layer. The adhesive layer may be, for example, a vertically aligning adhesive layer or a horizontally aligning adhesive layer. In this specification, the term "vertically aligning adhesive" may mean an adhesive that imparts a vertical alignment force to adjacent liquid crystal compounds and has an adhesive force capable of bonding an upper substrate and a lower substrate. In this specification, the term "horizontally aligning adhesive" may mean an adhesive that imparts a horizontal alignment force to adjacent liquid crystal compounds and has an adhesive force capable of bonding an upper substrate and a lower substrate. The pretilt angle of adjacent liquid crystal compounds relative to the vertically aligning adhesive may be within a range of 80 degrees to 90 degrees, 85 degrees to 90 degrees, or about 87 degrees to 90 degrees, and the pretilt angle of adjacent liquid crystal compounds relative to the horizontally aligning adhesive may be within a range of 0 degrees to 10 degrees, 0 degrees to 5 degrees, or 0 degrees to 3 degrees.

[0067] In this specification, the pretilt angle may refer to the angle that the director of the liquid crystal compound makes with respect to the liquid crystal alignment adhesive or alignment film and a plane horizontal thereto when no voltage is applied. In this specification, the director of the liquid crystal compound may refer to the optical axis or slow axis of the liquid crystal layer. Alternatively, the director of the liquid crystal compound may refer to the long axis direction when the liquid crystal compound is rod-shaped, or may refer to the axis parallel to the normal direction of the disc plane when the liquid crystal compound is discotic.

[0068] The thickness of the adhesive layer may be, for example, within a range of 3 μm to 15 μm. When the thickness of the adhesive layer is within this range, it may be advantageous to minimize defects such as pressure or bias of the adhesive when used in manufacturing a liquid crystal cell while ensuring adhesion between the upper and lower substrates.

[0069] The adhesive layer may be made of various types of adhesives known in the industry as OCA (Optically Clear Adhesive). The adhesive may be different from OCR (Optically Clear Resin) type adhesives that are cured after the objects are bonded in that the adhesive is cured before the objects are bonded. The adhesive may be, for example, an acrylic, silicone, epoxy, or urethane adhesive.

[0070] The adhesive layer may include a cured product of an adhesive resin. In one embodiment, the adhesive layer may include a silicone-based adhesive. The silicone-based adhesive may include a cured product of a curable silicone compound as an adhesive resin.

[0071] The type of the curable silicone compound is not particularly limited, and for example, a heat-curable silicone compound or an ultraviolet-curable silicone compound can be used. The curable silicone compound can be called an adhesive resin.

[0072] In one example, the curable silicone compound can be an addition cure silicone compound.

[0073] Specifically, the addition-curing silicon compound may be exemplified by, but is not limited to, (1) an organopolysiloxane containing two or more alkenyl groups in the molecule and (2) an organopolysiloxane containing two or more silicon-bonded hydrogen atoms in the molecule. The silicon compound can form a cured product by addition reaction, for example, in the presence of a catalyst described later.

[0074] More specific examples of the organopolysiloxane (1) that can be used in the present application include dimethylsiloxane-methylvinylsiloxane copolymers having both branched chain ends blocked by trimethylsiloxane groups, methylvinylpolysiloxanes having both branched chain ends blocked by trimethylsiloxane groups, dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymers having both branched chain ends blocked by trimethylsiloxane groups, dimethylpolysiloxanes having both branched chain ends blocked by dimethylvinylsiloxane groups, methylvinylpolysiloxanes having both branched chain ends blocked by dimethylvinylsiloxane groups, dimethylsiloxane-methylvinylsiloxane copolymers having both branched chain ends blocked by dimethylvinylsiloxane groups, dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymers having both branched chain ends blocked by dimethylvinylsiloxane groups, 1 2SiO 1 / 2 Siloxane units represented by and R 1 2R 2 SiO 1 / 2 The siloxane unit represented by and SiO 4 / 2 Organopolysiloxane copolymers containing siloxane units represented by R 1 2R 2 SiO 1 / 2 The siloxane unit represented by and SiO 4 / 2 Organopolysiloxane copolymers containing siloxane units represented by R 1 R 2 SiO 2 / 2 Siloxane units represented by and R 1 SiO 3 / 2 Siloxane units denoted by R 2 SiO 3 / 2and mixtures of two or more of the above. 1 is a hydrocarbon group other than an alkenyl group, specifically, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, or a heptyl group; an aryl group such as a phenyl group, a tolyl group, a xylyl group, or a naphthyl group; an aralkyl group such as a benzyl group or a phenethyl group; a halogen-substituted alkyl group such as a chloromethyl group, a 3-chloropropyl group, or a 3,3,3-trifluoropropyl group; 2 is an alkenyl group, specifically, a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, or the like.

[0075] More specific examples of the (2) organopolysiloxane that can be used in the present application include methylhydrogenpolysiloxanes blocked at both branched chain terminals with trimethylsiloxane groups, dimethylsiloxane-methylhydrogen copolymers blocked at both branched chain terminals with trimethylsiloxane groups, dimethylsiloxane-methylhydrogensiloxane-methylphenylsiloxane copolymers blocked at both branched chain terminals with trimethylsiloxane groups, dimethylpolysiloxanes blocked at both branched chain terminals with dimethylhydrogensiloxane groups, dimethylsiloxane-methylphenylsiloxane copolymers blocked at both branched chain terminals with dimethylhydrogensiloxane groups, methylphenylpolysiloxanes blocked at both branched chain terminals with dimethylhydrogensiloxane groups, R 1 3SiO 1 / 2 Siloxane units represented by and R 1 2HSiO 1 / 2 The siloxane unit represented by and SiO 4 / 2 Organopolysiloxane copolymers containing siloxane units represented by R 1 2HSiO 1 / 2 The siloxane unit represented by and SiO 4 / 2 Organopolysiloxane copolymers containing siloxane units represented by R 1 HSiO 2 / 2 Siloxane units represented by and R 1SiO 3 / 2 Siloxane units represented by HSiO 3 / 2 and mixtures of two or more of the above. 1 is a hydrocarbon group other than an alkenyl group, specifically, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, or a heptyl group; an aryl group such as a phenyl group, a tolyl group, a xylyl group, or a naphthyl group; an aralkyl group such as a benzyl group or a phenethyl group; a halogen-substituted alkyl group such as a chloromethyl group, a 3-chloropropyl group, or a 3,3,3-trifluoropropyl group; 2 is an alkenyl group, specifically, a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, or the like.

[0076] In one embodiment, when the adhesive layer is a vertically oriented adhesive layer, the surface energy of the adhesive layer may be 16 mN / m or less. The lower limit of the adhesive layer may be, for example, 5 mN / m or more. In one embodiment, when the adhesive layer is a horizontally oriented adhesive layer, the surface energy of the adhesive layer may be more than 16 mN / m. The upper limit of the surface energy may be, for example, 50 mN / m or less. The surface energy may be measured using a drop shape analyzer (Drop Shape Analyzer, KRUSS's DSA100 product). Specifically, the process of dropping deionized water, which has a known surface tension, onto the surface of the adhesive and measuring the contact angle is repeated five times, and the average value of the five contact angles obtained is calculated. In the same manner, the process of dropping diiodomethane, which has a known surface tension, onto the surface of the adhesive and measuring the contact angle is repeated five times, and the average value of the five contact angles obtained is calculated. Then, the surface energy was calculated by substituting the value (Strom value) related to the surface tension of the solvent by the Owens-Wendt-Rabel-Kaelble method using the average contact angles for deionized water and diiodomethane. The surface energy (γsurface) of the sample can be calculated by taking into account the dispersion force between non-polar molecules and the interaction force between polar molecules (γsurface = γdispersion + γpolar), and the ratio of the polar term (γpolar) in the surface energy γsurface can be defined as the polarity of the surface.

[0077] The upper and lower substrates of the liquid crystal cell may be attached to each other by an adhesive layer. Specifically, the adhesive layer of the upper substrate may be attached to the spacer of the lower substrate. When an alignment film is formed on the spacer of the lower substrate, the area of ​​the alignment film corresponding to the spacer may be attached to the adhesive layer of the upper substrate.

[0078] The liquid crystal layer may include a liquid crystal compound. The liquid crystal compound may be a liquid crystal compound whose alignment direction can be changed by application of an external action. In this specification, the term "external action" may refer to all external factors, such as an external voltage, that can affect the behavior of a substance contained in the liquid crystal layer. Therefore, a state without an external action may refer to a state without application of an external voltage or the like.

[0079] The type and properties of the liquid crystal compound may be appropriately selected in consideration of the purpose of the present application. In one example, the liquid crystal compound may be a nematic liquid crystal or a smectic liquid crystal. Nematic liquid crystal may refer to a liquid crystal in which rod-shaped liquid crystal molecules are arranged in parallel in the long axis direction of the liquid crystal molecules without any regularity in position, and smectic liquid crystal may refer to a liquid crystal in which rod-shaped liquid crystal molecules are regularly arranged to form a layered structure and are arranged in parallel with regularity in the long axis direction. According to one embodiment of the present application, the liquid crystal compound may be a nematic liquid crystal compound.

[0080] The nematic liquid crystal compound may be selected to have a clearing point of, for example, about 40° C. or more, 50° C. or more, 60° C. or more, 70° C. or more, 80° C. or more, 90° C. or more, 100° C. or more, or about 110° C. or more, or a phase transition point (i.e., a phase transition point from a nematic phase to an isotropic phase) within the above range. In one example, the clearing point or phase transition point may be about 160° C. or less, 150° C. or less, or about 140° C. or less.

[0081] The liquid crystal compound may be a non-reactive liquid crystal compound. The non-reactive liquid crystal compound may mean a liquid crystal compound that does not have a polymerizable group. The polymerizable group may be exemplified by, but is not limited to, an acryloyl group, an acryloyloxy group, a methacryloyl group, a methacryloyloxy group, a carboxy group, a hydroxy group, a vinyl group, or an epoxy group, and may include known functional groups known as polymerizable groups.

[0082] The dielectric anisotropy of the liquid crystal compound may be positive or negative. The absolute value of the dielectric anisotropy of the liquid crystal compound may be appropriately selected in consideration of the object of the present application. The term "dielectric anisotropy (Δε)" may mean the difference (ε / / -ε⊥) between the horizontal dielectric constant (ε / / ) and the vertical dielectric constant (ε⊥) of the liquid crystal. In this specification, the term horizontal dielectric constant (ε / / ) means a dielectric constant value measured along the direction of an electric field in a state where a voltage is applied so that the direction of the electric field caused by the director of the liquid crystal compound and the applied voltage is substantially horizontal, and the term vertical dielectric constant (ε⊥) means a dielectric constant value measured along the direction of the electric field in a state where a voltage is applied so that the direction of the electric field caused by the director of the liquid crystal compound and the applied voltage is substantially perpendicular. The dielectric anisotropy of the liquid crystal compound may be within a range of 5 to 25.

[0083] The refractive index anisotropy (Δn) of a liquid crystal compound can be appropriately selected in consideration of the purpose of the present application. In this specification, the term "refractive index anisotropy" refers to the extraordinary refractive index (n e , extraordinary refractive index) and ordinary refractive index (n o , ordinary refractive index) difference (n e -n o The refractive index anisotropy of the liquid crystal compound may be, for example, 0.01 to 0.3. The refractive index anisotropy may be 0.01 or more, 0.05 or more, or 0.07 or more, and may be 0.3 or less, 0.2 or less, 0.15 or less, or 0.13 or less.

[0084] The liquid crystal layer (layer in which the liquid crystal compound is present) may further include a dichroic dye. When the liquid crystal layer includes a dichroic dye, even if the liquid crystal cell includes an adhesive layer, the liquid crystal cell is less affected by the variation in cell gap during the bonding process of the outer substrate, and therefore, there is an advantage that the thickness of the intermediate layer for ensuring the structural stability and quality uniformity of the liquid crystal cell can be relatively thin. In one example, when a polymer film is used as the first and second intermediate layers, the liquid crystal layer may include a dichroic dye.

[0085] The dichroic dye can control the light transmittance variable property of the liquid crystal layer. In this specification, the term "dye" may refer to a material capable of intensively absorbing and / or transforming light in at least a part or the entire visible light range, for example, in the wavelength range of 400 nm to 700 nm, and the term "dichroic dye" may refer to a material capable of anisotropic absorption of light in at least a part or the entire visible light range.

[0086] The liquid crystal layer including the liquid crystal compound and the dichroic dye may be a GHLC layer (Guest Host Liquid Crystal Layer). In this specification, the term "GHLC layer (Guest Host Liquid Crystal Layer)" may refer to a functional layer in which the dichroic dye is arranged together with the liquid crystal compound, and which exhibits anisotropic light absorption characteristics in the alignment direction of the dichroic dye and in the direction perpendicular to the alignment direction. For example, the dichroic dye is a material whose light absorption rate changes depending on the polarization direction, and if it has a high absorption rate for light polarized in the long axis direction, it may be called a p-type dye, and if it has a high absorption rate for light polarized in the short axis direction, it may be called an n-type dye. In one example, when a p-type dye is used, polarized light vibrating in the long axis direction of the dye is absorbed, and polarized light vibrating in the short axis direction of the dye is less absorbed and can be transmitted. Hereinafter, unless otherwise specified, it is assumed that the dichroic dye is a p-type dye.

[0087] As the dichroic dye, for example, a known dye that is known to have a property of being aligned according to the alignment state of the liquid crystal compound by the so-called guest-host effect can be selected and used. Examples of such dichroic dyes include azo dyes, anthraquinone dyes, methine dyes, azomethine dyes, merocyanine dyes, naphthoquinone dyes, tetrazine dyes, phenylene dyes, quaterrylene dyes, benzothiadiazole dyes, diketopyrrolopyrrole dyes, squaraine dyes, and pyrromethene dyes, but the dyes applicable in the present application are not limited to the above.

[0088] The dichroic ratio of the dichroic dye, i.e., the absorption of light polarized parallel to the long axis of the dichroic dye divided by the absorption of light polarized perpendicular to the long axis, may be 5 or more, 6 or more, or 7 or more. The dye may satisfy the dichroic ratio at at least a part or any one of the wavelengths within the wavelength range of the visible light region, for example, within the wavelength range of about 380 nm to 700 nm or about 400 nm to 700 nm. The upper limit of the dichroic ratio may be, for example, about 20 or less, 18 or less, 16 or less, or 14 or less.

[0089] The content of the dichroic dye in the liquid crystal layer may be appropriately selected in consideration of the object of the present application. For example, the content of the dichroic dye in the liquid crystal layer may be 0.2 wt% or more. The content of the dichroic dye may be specifically 0.5 wt% or more, 1 wt% or more, 2 wt% or more, or 3 wt% or more. The upper limit of the content of the dichroic dye may be, for example, 10 wt% or less, 9 wt% or less, 8 wt% or less, 6 wt% or less, or 5 wt% or less. If the content of the dichroic dye in the liquid crystal layer is too low, it may be difficult to achieve the desired transmittance variable characteristic, and it may be insufficient to reduce the thickness of the intermediate layer for reducing the variation in the cell gap that may occur during the bonding process of the outer substrate. On the other hand, if the content of the dichroic dye in the liquid crystal layer is too high, there is a risk of precipitation. Therefore, it may be advantageous for the content of the dichroic dye to be within the above range.

[0090] The thickness of the liquid crystal layer is not particularly limited, and for example, the thickness of the liquid crystal layer may be about 0.01 μm or more, 0.05 μm or more, 0.1 μm or more, 0.5 μm or more, 1 μm or more, 1.5 μm or more, 2 μm or more, 2.5 μm or more, 3 μm or more, 3.5 μm or more, 4 μm or more, 4.5 μm or more, 5 μm or more, 5.5 μm or more, or 6 μm or more. The upper limit of the thickness of the liquid crystal layer is not particularly limited, and generally may be about 30 μm or less, 25 μm or less, 20 μm or less, or 15 μm or less. The thickness of the liquid crystal layer may be determined by the height of the spacer.

[0091] The liquid crystal layer can be switched between a first alignment state and a second alignment state different from the first alignment state. The switching can be controlled by applying an external energy such as a voltage. For example, the liquid crystal layer can be maintained in one of the first and second alignment states in the absence of an applied voltage, and can be switched to the other alignment state by applying a voltage.

[0092] In one example, the first alignment state may be a twisted alignment state, i.e., the liquid crystal layer may be capable of switching between the twisted alignment and another alignment state through application of external energy.

[0093] In one example, the liquid crystal layer can be switched between a twisted and a homeotropic state, and in one example, the liquid crystal layer can be in a homeotropic state with no voltage applied and in a twisted state with a voltage applied.

[0094] In this specification, the "vertical alignment state" refers to a state in which the directors of the liquid crystal compound in the liquid crystal layer are aligned approximately perpendicular to the plane of the liquid crystal layer, and for example, the angle that the directors of the liquid crystal compound make with respect to the plane of the liquid crystal layer can be, for example, within a range of approximately 80 degrees to 100 degrees or 85 degrees to 95 degrees, or can be approximately 90 degrees.

[0095] In this specification, the term "twisted alignment state" may refer to a helical structure in which the directors of liquid crystal compounds are twisted along a virtual helical axis in a liquid crystal layer to form a layer. The twisted alignment state may be embodied as a vertical, horizontal, or tilted alignment state. That is, the vertical twist alignment mode is a state in which individual liquid crystal compounds are twisted along a helical axis in a vertically aligned state to form a layer, the horizontal twist alignment mode is a state in which individual liquid crystal compounds are twisted along a helical axis in a horizontally aligned state to form a layer, and the tilted twist alignment mode is a state in which individual liquid crystal compounds are twisted along a helical axis in a tilted state to form a layer. According to the present application, the twisted alignment state may be a twisted alignment state of a horizontal alignment state.

[0096] In the twisted alignment state, the ratio (d / p) of the thickness d to the pitch p of the liquid crystal layer may be 20 or less, with the lower limit being 0.5 or more. When the ratio (d / p) of the thickness d to the pitch p in the twisted alignment state is within the above range, the optical device can exhibit excellent light transmittance variable characteristics even without a polarizer. In general, when the ratio d / p is 0.7 or more and less than 2.5, it can be called STN (Super Twisted Nematic) mode, and when the ratio d / p is 2.5 or more, it can be called HTN (Highly Twisted Nematic) driving mode.

[0097] The pitch p of the liquid crystal layer can be measured by a measurement method using a wedge cell, specifically, by the method described in Simple method for accurate measurements of the cholesteric pitch using a "stripe-wedge Grandjean-Cano cell" by D. Podolskyy et al. (Liquid Crystals, Vol. 35, No. 7, July 2008, pp. 789-791). The ratio (d / p) can be achieved by introducing an appropriate amount of chiral dopant into the liquid crystal layer.

[0098] The liquid crystal layer may further include a chiral dopant. When the liquid crystal layer includes a chiral agent, a twisted alignment state may be realized. The chiral agent (or chiral dopant) that may be included in the liquid crystal layer may be any agent capable of inducing a desired twisting without damaging the liquid crystal property, for example, nematic regularity. The chiral agent for inducing rotation in the liquid crystal compound must at least include chirality in its molecular structure. Examples of the chiral agent include a compound having one or more asymmetric carbons, a compound having an asymmetric point on a heteroatom such as a chiral amine or chiral sulfoxide, or a compound having an axially asymmetric, optically active site such as cumulene or binaphthol. The chiral agent may be, for example, a low molecular weight compound having a molecular weight of 1,500 or less. As the chiral agent, commercially available chiral nematic liquid crystals, such as chiral dopant liquid crystal S-811 available from Merck or LC756 available from BASF, may be used.

[0099] The application ratio of the chiral dopant is selected so as to achieve the desired ratio (d / p). In general, the content (wt%) of the chiral dopant can be calculated by the formula: 100 / HTP (Helixcal Twisting power) x pitch p (nm). The HTP indicates the twisting strength of the chiral dopant, and the content of the chiral dopant can be determined by taking into account the desired pitch with reference to the formula.

[0100] The upper substrate of the liquid crystal cell may further include a first electrode layer 10b between the first base layer 10a and the adhesive layer 10c. The first electrode layer 10b may be in contact with the inner surface of the first base layer 10a. The adhesive layer 10c may be in contact with the inner surface of the first electrode layer 10b. The lower substrate of the liquid crystal cell may further include a second electrode layer 20b between the second base layer 20a and the spacer 20c. The second electrode layer 20b may be in contact with the inner surface of the second base layer 20a. The spacer 20c may be in contact with the inner surface of the second electrode layer 20b.

[0101] The first electrode layer and the second electrode layer may perform a role of applying an external action, for example, application of an electric field, so that a material contained in the liquid crystal layer transmits or blocks incident light. In one example, the first electrode layer and / or the second electrode layer may include, but is not limited to, a conductive polymer, a conductive metal, a conductive nanowire, or a metal oxide such as ITO (Indium Tin Oxide). The first electrode layer and / or the second electrode layer may be formed by depositing, for example, the conductive polymer, the conductive metal, the conductive nanowire, or a metal oxide such as ITO (Indium Tin Oxide).

[0102] The lower substrate of the liquid crystal cell may further include an alignment film 20d. The alignment film 20d may be present on the spacer 20c. That is, the upper surface and / or the side surface of the spacer 20c may be in contact with the alignment film. The lower surface of the spacer 20c may be in contact with the second electrode layer 20b. Since the adhesive layer included in the upper substrate may have liquid crystal alignment properties, the upper substrate may not include an alignment film. That is, the inner surface of the first electrode layer 10b may not include an alignment film.

[0103] In this specification, the combination of the first base layer, the first electrode layer, and the adhesive layer may be referred to as an upper substrate, and the combination of the second base layer, the second electrode layer, the spacer, and the alignment layer may be referred to as a lower substrate. In a liquid crystal cell, the upper substrate does not include a separate alignment layer other than the adhesive layer, and the lower substrate may include an alignment layer.

[0104] The alignment film and the liquid crystal layer may be in contact with each other. The alignment film may be a vertical alignment film or a horizontal alignment film. In this specification, the term "horizontal alignment film" may refer to a layer containing an alignment material that imparts a horizontal alignment force to the liquid crystal compound present in the adjacent liquid crystal layer. In this specification, the term "vertical alignment film" may refer to a layer containing an alignment material that imparts a vertical alignment force to the liquid crystal compound present in the adjacent liquid crystal layer. The pretilt angle of the adjacent liquid crystal compound with respect to the vertical alignment film may be within a range of 80 degrees to 90 degrees, 85 degrees to 90 degrees, or about 87 degrees to 90 degrees, and the pretilt angle of the adjacent liquid crystal compound with respect to the horizontal alignment film may be within a range of 0 degrees to 10 degrees, 0 degrees to 5 degrees, or 0 degrees to 3 degrees. Unlike the adhesive layer, the alignment film may not have an adhesive force that bonds the upper substrate and the lower substrate. In one example, the alignment film may have a peel force close to 0 with respect to the upper substrate in the state of the liquid crystal cell of FIG. 2.

[0105] The alignment film may be a rubbing alignment film or a photo-alignment film. The alignment direction of the alignment film may be the rubbing direction in the case of a rubbing alignment film, and the direction of the irradiated polarized light in the case of a photo-alignment film. The alignment direction may be confirmed by a detection method using an absorbing linear polarizer. Specifically, the alignment direction may be confirmed by arranging an absorbing linear polarizer on one side of the liquid crystal layer in a state where the liquid crystal compound contained in the liquid crystal layer is horizontally aligned, and measuring the transmittance by rotating the polarizer 360 degrees. In the above state, when light is irradiated to the liquid crystal layer or the absorbing linear polarizer side and the brightness (transmittance) is measured on the other side, if the absorption axis or transmission axis coincides with the alignment direction of the liquid crystal alignment film, the transmittance tends to be low, but the alignment direction may be confirmed through a simulation that reflects the refractive index anisotropy of the applied liquid crystal compound. A method for confirming the alignment direction depending on the mode of the liquid crystal layer is well known, and the alignment direction of the alignment film may be confirmed by such a well-known method in the present application.

[0106] Examples of the alignment film include materials that are known to exhibit alignment ability through rubbing alignment, such as polyimide compounds, poly(vinyl alcohol) compounds, poly(amic acid) compounds, polystyrene compounds, polyamide compounds, and polyoxyethylene compounds, as well as polyimide compounds, polyamic acid compounds, polynorbornene compounds, phenylmaleimide copolymer compounds, polyvinylcinamate compounds, polyazobenzene compounds, polyethyleneimide compounds, polyvinylalcohol compounds, polyimide compounds, polyethylene compounds, polystyrene compounds, polyphenylenephthalamide compounds, polyester compounds, CMPI (chloromethylated The material may include, but is not limited to, one or more selected from the group consisting of materials known to be capable of exhibiting alignment ability upon light irradiation, such as a polyimide compound, a PVCI (polyvinylcinnamate) compound, and a polymethyl methacrylate compound.

[0107] The spacer 20c can maintain the distance between the upper and lower substrates. A liquid crystal layer can be present in the area where no spacer is present between the upper and lower substrates.

[0108] The spacer may be a patterned spacer. The spacer may have a column shape or a partition wall shape. The partition wall may divide the space between the lower substrate and the upper substrate into two or more spaces. In the area where the spacer is not present, other films or other layers present thereunder may be exposed. For example, the second electrode layer may be exposed in the area where the spacer is not present. The alignment film may cover the spacer and the second electrode layer exposed in the area where the spacer is not present. In a liquid crystal cell in which the upper substrate and the lower substrate are bonded together, the alignment film present on the spacer of the lower substrate and the adhesive layer of the upper substrate may be in contact with each other.

[0109] The spacer-free region between the upper and lower substrates may contain liquid crystal compounds and the above-mentioned additives, such as dichroic dyes, chiral agents, etc. The shape of the spacer is not particularly limited, and may be applied without limitation to have multiple sides, such as a circle, an ellipse, or other polygonal shapes.

[0110] The spacer may include a curable resin. The type of the curable resin is not particularly limited, and may be, for example, a thermosetting resin or a photocurable resin, such as an ultraviolet curable resin. The thermosetting resin may be, for example, a silicon resin, a silicon resin, a furan resin, a polyurethane resin, an epoxy resin, an amino resin, a phenol resin, a urea resin, a polyester resin, or a melamine resin, but is not limited thereto. The ultraviolet curable resin may be, for example, an acrylic polymer, such as a polyester acrylate polymer, a polystyrene acrylate polymer, an epoxy acrylate polymer, a polyurethane acrylate polymer, or a polybutadiene acrylate polymer, a silicon acrylate polymer, or an alkyl acrylate polymer, but is not limited thereto.

[0111] The spacer may be formed by a patterning process. For example, the spacer may be formed by a photolithography process. The photolithography process may include a process of applying a curable resin composition onto a substrate layer or an electrode layer, and then irradiating ultraviolet light through a pattern mask. The pattern mask may be patterned into an ultraviolet light transmitting region and an ultraviolet light blocking region. The photolithography process may further include a process of washing the curable resin composition irradiated with ultraviolet light. The region irradiated with ultraviolet light is cured, and the region not irradiated with ultraviolet light remains in a liquid state, so that it can be patterned into a partition wall by removing it through a washing process. In the photolithography process, in order to easily separate the resin composition and the pattern mask after ultraviolet light irradiation, the pattern mask may be subjected to a release treatment or a release paper may be placed between the layer of the resin composition and the pattern mask.

[0112] The width (line width), interval (pitch), height (thickness), and area of ​​the spacer may be appropriately selected within a range that does not impair the object of the present application. For example, the width (line width) of the spacer may be in the range of 10 μm to 500 μm or in the range of 10 μm to 50 μm. The interval (pitch) of the spacer may be in the range of 10 μm to 1000 μm or in the range of 100 μm to 1000 μm. The area of ​​the spacer may be about 5% or more and 50% or less with respect to 100% of the total area of ​​the second base layer. When the area of ​​the spacer is within the above range, it may be advantageous to ensure excellent electro-optical properties while adequately ensuring adhesion between the upper substrate and the lower substrate. The height (thickness) of the spacer may be, for example, in the range of 1 μm to 30 μm or 3 μm to 20 μm.

[0113] The optical device may further include an outer layer surrounding a side of the liquid crystal cell. In the optical device, the area above the liquid crystal cell may be smaller than the area above the first outer substrate or the second outer substrate. Also, the area above the liquid crystal cell may be smaller than the area above the first to fourth adhesive layers included in the optical device. Also, the area above the liquid crystal cell may be smaller than the area above the first to second intermediate layers included in the optical device.

[0114] In one example, the liquid crystal cell may be encapsulated by the first adhesive layer to the fourth adhesive layer and the outer layer. In the present application, the term encapsulation may mean covering the entire surface of the liquid crystal cell with the adhesive layer and the outer layer. Depending on the desired structure, for example, the encapsulation structure may be realized by vacuum-pressing a laminate including a first outer substrate, a first adhesive layer, a first polarizer, a second adhesive layer, a liquid crystal cell, a third adhesive layer, a second polarizer, a fourth adhesive layer, and a second outer substrate in that order, and including an outer layer surrounding the side of the liquid crystal cell. Such an encapsulation structure significantly improves the durability and weather resistance of the optical device, and as a result, it can be stably applied to outdoor applications such as sunroofs.

[0115] In one example, the optical device may satisfy the following Equation 3. This may be advantageous in eliminating problems such as damage to the outer substrate and residual air bubbles after autoclaving.

[0116] [Formula 3]

[0117] 0.3×B1 <B2<1.8×B1

[0118] In Equation 3, B1 is the thickness of the liquid crystal cell (unit: μm), and B2 is the thickness of the outer layer (unit: μm). The thickness B1 of the liquid crystal cell may mean the sum of the thickness of the first base layer, the thickness of the adhesive layer, the thickness of the liquid crystal layer (height of the spacer), and the thickness of the second base layer. That is, when the thickness B1 of the liquid crystal cell is discussed in this specification, the thicknesses of the electrode layer and the alignment film may be excluded because they are in the nanometer level. In Equation 3, B2 may be 0.5×B1 or more, 0.6×B1 or more, 0.7×B1 or more, 0.8×B1 or more, 0.9×B1 or more, 1.1×B1 or more, and may be 1.5×B1 or less, 1.3×B1 or less, 1.0×B1 or less, or 0.9×B1 or less.

[0119] In one example, the storage modulus of the outer layer at 110° C. and 1 Hz frequency may be 100,000 Pa or less. The storage modulus of the outer layer at 110° C. and 1 Hz frequency may be 90,000 Pa or less, 80,000 Pa or less, 70,000 Pa or less, or 50,000 Pa or less, and 10,000 Pa or more, or 30,000 Pa or more. During the autoclave process for bonding the outer substrates to both sides of the liquid crystal cell, the outer layer surrounding the sides of the liquid crystal cell has a low storage modulus at high temperatures, so that a strong pressure may be applied to the edge region of the liquid crystal cell adjacent to the outer layer. As a result, the edge region of the liquid crystal cell may experience a collapse (pressure) of the cell gap and an overflow of the liquid crystal during bonding of the outer substrates due to uneven pressure being concentrated in a local area. According to the present application, the above phenomenon can be solved.

[0120] The outer layer may include, for example, a thermoplastic polyurethane (TPU) adhesive, a polyamide adhesive, a polyester adhesive, an ethylene vinyl acetate (EVA) adhesive, an acrylic adhesive, a silicone adhesive, or a polyolefin adhesive. In one example, the outer layer may be formed of the same material as the first to fourth adhesive layers.

[0121] The present application also relates to a method for manufacturing an optical device. The method for manufacturing the optical device may include preparing a laminate including a first outer substrate, a first adhesive layer, a first polarizer, a second adhesive layer, a liquid crystal cell, a third adhesive layer, a second polarizer, a fourth adhesive layer, and a second outer substrate in that order, and including an outer layer surrounding a side of the liquid crystal cell, and subjecting the laminate to autoclaving. Unless otherwise specified, the same contents described in the optical device may be applied to the method for manufacturing the optical device.

[0122] When the optical device further includes other elements other than the liquid crystal cell and the polarizer, the laminate can further include the other elements other than the liquid crystal cell and the polarizer at desired positions.

[0123] The autoclaving step may be performed by applying heat and / or pressure to the laminate formed after the lamination step.

[0124] The conditions of the autoclave process are not particularly limited, and may be performed under appropriate temperature and pressure depending on the type of intermediate layer applied. The temperature of the typical autoclave process is about 80°C or more, 90°C or more, or 100°C or more, and the pressure is 2 atm or more, but is not limited thereto. The upper limit of the process temperature may be about 200°C or less, 190°C or less, 180°C or less, or 170°C or less, and the upper limit of the process pressure may be about 10 atm or less, 9 atm or less, 8 atm or less, 7 atm or less, or 6 atm or less.

[0125] The optical device may be used in a variety of applications, such as eyewear, such as sunglasses, AR (Augmented Reality) or VR (Virtual Reality) eyewear, building exteriors, and vehicle sunroofs. In one example, the optical device may be a vehicle sunroof by itself. For example, the optical device may be mounted in at least one opening in a vehicle body having the vehicle body and used as a vehicle sunroof. Effect of the Invention

[0126] The optical device of the present application properly maintains the cell gap of the liquid crystal cell, has excellent adhesion between the upper and lower substrates, and can solve the phenomenon of the liquid crystal cell being squeezed and overflowing when the outer substrate is attached. [Brief description of the drawings]

[0127] [Figure 1] 1 illustrates an exemplary optical device of the present application.

[0128] [Diagram 2] 1 illustrates an exemplary liquid crystal cell of the present application.

[0129] [Diagram 3] 1 is an image showing the pressing and overflow defects observed after bonding of the optical device of Example 1.

[0130] [Figure 4] 13 is an image showing the pressing and overflow defects observed after bonding of the optical device of Comparative Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0131] Hereinafter, the present application will be described in detail with reference to examples, but the scope of the present application is not limited to the following examples.

[0132] Example 1.

[0133] Liquid crystal cell manufacturing

[0134] A PET film (SK Corporation) with a thickness of about 145 μm and a horizontal x vertical area of ​​900 mm x 600 mm was prepared as the first base layer. ITO (indium-tin-oxide) was deposited to a thickness of 50 nm on the first base layer to form a first electrode layer. An adhesive composition (KR-3700, Shin-Etsu Corporation) was coated on the first electrode layer and then dried at about 150° C. for about 5 minutes to form an adhesive layer with a thickness of about 10 μm. The storage modulus of the adhesive layer at a temperature of 25° C. and a frequency of 1 Hz was about 754,500 Pa, and the loss modulus at a temperature of 25° C. and a frequency of 1 Hz was about 906,687 Pa. The combination of the first base layer, the first electrode layer, and the adhesive layer is referred to as the upper substrate.

[0135] A PET film (SK) with a thickness of about 145 μm and a horizontal x vertical area of ​​900 mm x 600 mm was prepared as the second substrate layer. ITO (indium-tin-oxide) was deposited on the second substrate layer to a thickness of 50 nm to form a second electrode layer. An acrylic resin composition (KAD-03, Minutek) was coated on the second electrode layer, and a honeycomb-shaped spacer was formed by photolithography. The pitch of the regular hexagons (closed shapes) constituting the honeycomb was about 350 μm, the height was about 6 μm, and the line width was about 30 μm. A vertical alignment film (Nissan, 5661) was coated on the spacer to a thickness of about 300 nm, and then rubbed in one direction. The combination of the second substrate layer, the second electrode layer, the spacer, and the vertical alignment film is called the lower substrate.

[0136] A liquid crystal composition was coated on the vertical alignment film of the lower substrate to form a liquid crystal layer, and then the adhesive layer of the upper substrate was laminated to face the surface coated with the liquid crystal composition to manufacture a liquid crystal cell. The liquid crystal composition contained a liquid crystal compound (JNC, SHN-5011XX) and a chiral dopant (HCCH, S811), and the pitch p of the liquid crystal layer was about 20 μm. The liquid crystal cell was an RTN mode liquid crystal cell in an initial vertical alignment state. The horizontal and vertical areas of the liquid crystal cell were 900 mm x 600 mm, and the thickness was about 306 μm.

[0137] Optical Device Manufacturing

[0138] A laminate including a first outer substrate, a first adhesive layer, a first intermediate layer, a second adhesive layer, the manufactured liquid crystal cell, a third adhesive layer, a second intermediate layer, a fourth adhesive layer, and a second outer substrate, in that order, and an outer layer surrounding the side of the liquid crystal cell, was prepared. At this time, the first base layer of the liquid crystal cell was disposed close to the first outer substrate, and the second base layer of the liquid crystal cell was disposed close to the second outer substrate. The second outer substrate was disposed in the direction of gravity compared to the first outer substrate.

[0139] The first and second outer substrates were made of double-curved glass with a thickness of about 3 mm and an area of ​​1100 mm x 800 mm (horizontal x vertical). The first, second, third and fourth adhesive layers were made of TPU layers (Argotec) with a thickness of about 380 μm. The storage modulus of the TPU layer (Argotec) at 25°C and 1 Hz was 3,357,730 Pa, and the loss modulus at 25°C and 1 Hz was 1,485,510 Pa. The outer layer was made of a TPU layer (Argotec) with a thickness of 380 μm. The TPU layer of the outer layer had a storage modulus of 3,357,730 Pa at 25°C and 1 Hz, and a storage modulus of 49,138 Pa at 110°C and 1 Hz. The first and second intermediate layers were each a polarizer with a thickness of about 95 μm and an area of ​​960 mm x 600 mm (horizontal x vertical). The polarizer was a PVA-based stretched film dyed with iodine.

[0140] The laminate was subjected to an autoclave process at a temperature of about 110° C. and a pressure of about 2 atm to fabricate an optical device.

[0141] When the optical device is observed in the normal direction, the area of ​​the liquid crystal cell is included in the area of ​​the first intermediate layer and the area of ​​the second intermediate layer. When the optical device is observed in the normal direction, the area of ​​the first intermediate layer is included in the area of ​​the first outer substrate, and the area of ​​the second intermediate layer is included in the area of ​​the second outer substrate. When the optical device is observed in the normal direction, the areas of the first outer substrate and the second outer substrate are approximately the same. When the optical device is observed in the normal direction, the area of ​​the first intermediate layer is approximately the same as the area of ​​the first outer substrate. When the optical device is observed in the normal direction, the difference (L1-L2) between the distance L1 between the outer portion of the first outer substrate and the outer portion of the liquid crystal cell and the distance L2 between the outer portion of the first outer substrate and the outer portion of the first intermediate layer was 30 mm on both sides (left and right) of the liquid crystal cell (distance D1 based on the first outer substrate). In addition, when the optical device was observed in the normal direction, the difference (L1-L2) between the distance L1 between the outer portion of the second outer substrate and the outer portion of the liquid crystal cell and the distance L2 between the outer portion of the second outer substrate and the outer portion of the second intermediate layer was 30 mm (distance D2 based on the second outer substrate) on both sides (left and right) of the liquid crystal cell. In the above, L1 on the first outer substrate side and L1 on the second outer substrate side were each 100 mm, and L2 on the first outer substrate side and L2 on the second outer substrate side were each 70 mm. In addition, the difference in thickness between the outer layer and the liquid crystal cell was 74 μm.

[0142] Example 2

[0143] An optical device was manufactured in the same manner as in Example 1, except that a laminate of a 380 μm thick TPU layer (Argotec) and a 150 μm thick TPU layer (Argotec) was used as the outer layer, changing the difference in thickness between the outer layer and the liquid crystal layer to 224 μm.

[0144] Example 3

[0145] An optical device was manufactured in the same manner as in Example 1, except that the distance L1-L2 based on the outer edge of the first outer substrate was changed to 25 mm and the distance L1-L2 based on the second outer substrate was changed to 25 mm by using polarizers with a horizontal length of 950 mm as the first and second intermediate layers. In the above, L1 on the first outer substrate side and L1 on the second outer substrate side were each 100 mm, and L2 on the first outer substrate side and L2 on the second outer substrate side were each 75 mm.

[0146] Example 4

[0147] An optical device was manufactured in the same manner as in Example 1, except that the distance L1-L2 based on the outer edge of the first outer substrate was changed to 20 mm and the distance L1-L2 based on the second outer substrate was changed to 20 mm by using polarizers with a horizontal length of 940 mm as the first and second intermediate layers. In the above, L1 on the first outer substrate side and L1 on the second outer substrate side were each 100 mm, and L2 on the first outer substrate side and L2 on the second outer substrate side were each 80 mm.

[0148] Example 5

[0149] In manufacturing the liquid crystal cell, a liquid crystal cell was manufactured in the same manner as in Example 1, except that a PET film (SK Corporation) with a width x length of 560 mm x 600 mm was used as the first and second base layers. The width x length of the liquid crystal cell was 560 mm x 600 mm, and the thickness was about 306 μm. The subsequent processes were performed in the same manner as in Example 1 to manufacture an optical device. The distance L1-L2 based on the outer edge of the first outer substrate was 200 mm, and the distance L1-L2 based on the second outer substrate was changed to 200 mm. L1 on the first outer substrate side and L1 on the second outer substrate side were each 270 mm, and L2 on the first outer substrate side and L2 on the second outer substrate side were each 70 mm.

[0150] Example 6

[0151] A liquid crystal cell was manufactured in the same manner as in Example 1, except that a liquid crystal composition containing 2 wt% of dichroic dye (BASF, X12) was used. In addition, an optical device was manufactured in the same manner as in Example 1, except that a PET film (including UV cut function) with a thickness of about 125 μm and an area of ​​940 mm×600 mm was used instead of a polarizer as the first intermediate layer and the second intermediate layer, and the distance L1-L2 based on the outer edge of the first outer substrate was changed to 20 mm, and the distance L1-L2 based on the second outer substrate was changed to 20 mm. In the above, L1 on the first outer substrate side and L1 on the second outer substrate side were each 100 mm, and L2 on the first outer substrate side and L2 on the second outer substrate side were each 80 mm.

[0152] Comparative Example 1

[0153] An optical device was manufactured in the same manner as in Example 1, except that the distance L1-L2 based on the outer edge of the first outer substrate was changed to 15 mm and the distance L1-L2 based on the second outer substrate was changed to 15 mm by using polarizers with a horizontal length of 930 mm as the first and second intermediate layers. In the above, L1 on the first outer substrate side and L1 on the second outer substrate side were each 100 mm, and L2 on the first outer substrate side and L2 on the second outer substrate side were each 85 mm.

[0154] Comparative Example 2

[0155] An optical device was manufactured in the same manner as in Example 1, except that the distance L1-L2 based on the outer edge of the first outer substrate was changed to 10 mm and the distance L1-L2 based on the second outer substrate was changed to 10 mm by using polarizers with a horizontal length of 920 mm as the first and second intermediate layers. In the above, L1 on the first outer substrate side and L1 on the second outer substrate side were each 100 mm, and L2 on the first outer substrate side and L2 on the second outer substrate side were each 90 mm.

[0156] Comparative Example 3

[0157] An optical device was manufactured in the same manner as in Example 1, except that the distance L1-L2 based on the outer part of the first outer substrate was changed to 10 mm by using a polarizer with a horizontal length of 920 mm as the first intermediate layer and the second intermediate layer, the distance L1-L2 based on the second outer substrate was changed to 10 mm, and the difference in thickness between the outer layer and the liquid crystal cell was changed to 224 μm by using a laminate of a TPU layer (Argotec) with a thickness of 380 μm and a TPU layer (Argotec) with a thickness of 150 μm as the outer layer. In the above, L1 on the first outer substrate side and L1 on the second outer substrate side were each 100 mm, and L2 on the first outer substrate side and L2 on the second outer substrate side were each 90 mm.

[0158] Comparative Example 4

[0159] An optical device was manufactured in the same manner as in Example 1, except that the distance L1-L2 based on the outer portion of the first outer substrate was changed to 10 mm by using a polarizer with a horizontal length of 920 mm as the first intermediate layer and the second intermediate layer, the distance L1-L2 based on the second outer substrate was changed to 10 mm, and the difference in thickness between the outer layer and the liquid crystal cell was changed to 454 μm by using a laminate in which two TPU layers (Argotec) with a thickness of 380 μm were laminated as the outer layer. In the above, L1 on the first outer substrate side and L1 on the second outer substrate side were each 100 mm, and L2 on the first outer substrate side and L2 on the second outer substrate side were each 90 mm.

[0160] Comparative Example 5

[0161] An optical device was manufactured in the same manner as in Example 1, except that the distance L1-L2 based on the outer edge of the first outer substrate was changed to 0 mm and the distance L1-L2 based on the second outer substrate was changed to 0 mm by using polarizers with a horizontal length of 900 mm as the first and second intermediate layers. In the above, L1 on the first outer substrate side and L1 on the second outer substrate side were each 100 mm, and L2 on the first outer substrate side and L2 on the second outer substrate side were each 100 mm.

[0162] Evaluation example 1. Evaluation of defects such as pressing and overflow after bonding

[0163] The optical devices of Examples 1 to 6 and Comparative Examples 1 to 5 were evaluated for pressing and overflow defects after bonding of the outer substrates, and the results are shown in Table 1. FIG. 3 is an image of pressing and overflow defects observed after bonding of the optical device of Example 1, and FIG. 4 is an image of pressing and overflow defects observed after bonding of the optical device of Comparative Example 2. As shown in FIG. 4, in Comparative Example 2, uneven pressure was applied to the edge portion, and liquid crystal deviation and overflow defects due to pressing were observed. Comparative Examples 1 and 3 to 5 also showed similar results to Comparative Example 2. On the other hand, in Example 1, as shown in FIG. 3, the above defects were not observed. Examples 2 to 6 also showed similar results to Example 1.

[0164] [Table 1] [Explanation of symbols]

[0165] 101: First outer circuit board 102: Second outer circuit board 200: Liquid crystal cell 301: First middle layer 302: Second middle layer 401: First adhesive layer 402: Second adhesive layer 403; 3rd adhesive layer 404: 4th adhesive layer 500: Outer layer 10a: First base layer 10b: First electrode layer 10c:Adhesive layer 20a: Second base layer 20b: Second electrode layer 20c: Spacer 20d: Alignment film 30: Liquid crystal layer

Claims

1. a first outer substrate; a liquid crystal cell and a second outer substrate, the liquid crystal cell includes an upper substrate including a first base layer and an adhesive layer; a lower substrate including a second base layer and a spacer; and a liquid crystal layer including a liquid crystal compound between the upper substrate and the lower substrate, a first intermediate layer between the first outer substrate and the liquid crystal cell, and a second intermediate layer between the second outer substrate and the liquid crystal cell; An optical device comprising at least one region satisfying the following formula 1: [Formula 1] 20mm≦L １ -L ２ In formula 1, L １ is the distance between the outer periphery of the first outer substrate and the outer periphery of the liquid crystal cell or the distance between the outer periphery of the second outer substrate and the outer periphery of the liquid crystal cell, and L ２ is the distance between the outer periphery of the first outer substrate and the outer periphery of the first intermediate layer, or the distance between the outer periphery of the second outer substrate and the outer periphery of the second intermediate layer.

2. The optical device according to claim 1 , wherein when the optical device is observed in a normal direction, the region of the liquid crystal cell is included in the region of the first intermediate layer or the region of the second intermediate layer.

3. The optical device according to claim 1 , comprising two or more regions that satisfy the formula (1).

4. The optical device of claim 1 , wherein the first intermediate layer and the second intermediate layer are each a polarizer or a polymer film.

5. The optical device of claim 4 , wherein the first intermediate layer and the second intermediate layer are each a polarizer.

6. The polymer film includes a TAC (triacetyl cellulose) film, a DAC (diacetyl cellulose) film, a COP (cycloolefin copolymer) film, a PA (polyacrylate) film, a PMMA (poly(methyl methacrylate) film, a PC (polycarbonate) film, a PE (polyethylene) film, a PP (polypropylene) film, a PVA (polyvinyl 5. The optical device of claim 4, comprising one or more films selected from the group consisting of alcohol film, PI (polyimide) film, PSF (polysulfone) film, PPS (polyphenylsulfone) film, PES (polyethersulfone) film, PEEK (polyetheretherketon) film, PEI (polyetherimide) film, PEN (polyethylenenaphthalate) film and PET (polyethyleneterephthalate) film.

7. The optical device of claim 1 , wherein the first outer substrate and the second outer substrate are each a glass substrate.

8. L １ -L ２ The optical device of claim 1 , wherein

9. 2. The optical device according to claim 1, which satisfies the following formula 2: [Formula 2] A1<A2<A3 In Equation 2, A1 is the area of ​​the liquid crystal cell (unit: mm ２ ), and A2 is the area of ​​the first intermediate layer or the second intermediate layer (unit: mm ２ ), and A3 is the area of ​​the first outer substrate or the second outer substrate (unit: mm ２ ).

10. 2. The optical device of claim 1, further comprising a first adhesive layer between the first outer substrate and the first intermediate layer, a second adhesive layer between the first intermediate layer and the liquid crystal cell, a third adhesive layer between the liquid crystal cell and the second intermediate layer, and a fourth adhesive layer between the second intermediate layer and the second outer substrate.

11. The optical device of claim 1 , further comprising an outer layer surrounding a side surface of the liquid crystal cell.

12. The optical device according to claim 11, which satisfies the following formula 3: [Formula 3] 0.3×B1<B2<1.8×B1 In Equation 3, B1 is the thickness of the liquid crystal cell (unit: μm), and B2 is the thickness of the outer layer (unit: μm).

13. 12. The optical device of claim 11, wherein the outer layer has a storage modulus of 100,000 Pa or less at a temperature of 110° C. and a frequency of 1 Hz.

14. The optical device according to claim 1 , wherein the liquid crystal layer switches between orientation states by application of a voltage.

15. The optical device of claim 1 , wherein the upper substrate further comprises a first electrode layer between the first base layer and the adhesive layer, and the lower substrate further comprises a second electrode layer between the second base layer and the spacer.

16. The optical device of claim 15 , wherein the upper substrate does not include an alignment layer, and the lower substrate further includes an alignment layer.

17. 17. A motor vehicle comprising: a vehicle body having one or more openings formed therein; and an optical device according to any one of claims 1 to 16 mounted in said openings.

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