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 filed on 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 for forming a pillar- or wall-shaped organic film pattern on one substrate at the cell gap height and then using an adhesive to secure it to the opposite substrate. However, this technique requires the adhesive to be positioned only on the pillar or wall surfaces, and the technique of micro-stamping the adhesive onto the pillar or wall surfaces is difficult to process, making it difficult to control the thickness and area of ​​the adhesive. Furthermore, there is a high possibility that the adhesive will be extruded when the upper and lower substrates are bonded, which could contaminate the alignment film or liquid crystal. Summary of the Invention [Problem to be solved by the invention]

[0005] To maintain the cell gap of the liquid crystal cell and ensure adhesion between the upper and lower substrates, it is possible to form a spacer and an alignment film on the lower substrate, and then form an adhesive layer on the upper substrate that has both liquid crystal alignment and adhesive properties before 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 can be applied to the edge region of the liquid crystal cell adjacent to the outer layer. As a result, uneven pressure can be concentrated in localized areas at the edge region of the liquid crystal cell, which can cause cell gap collapse (pressure) and liquid crystal overflow during bonding of the outer substrates.

[0006] The object of the present application is to provide an optical device in which the cell gap of the 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 the 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 measured at room temperature unless otherwise specified. The term "room temperature" refers to a natural temperature without heating or cooling, typically a temperature within the range of about 10°C to 30°C, or about 23°C or about 25°C. Unless otherwise specified, 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 measured at room pressure unless otherwise specified. The term "room pressure" refers to a natural pressure without heating or cooling, typically about 1 atmosphere.

[0008] The present application relates to an optical device. FIG. 1 exemplarily illustrates the optical device of the present 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 as 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 and lower substrates. 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 positioned between the liquid crystal cell 200 and the first outer substrate 101. The optical device may include a second intermediate layer 302 positioned 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. This can distribute local pressure applied to the edge of the liquid crystal cell during the process of bonding the liquid crystal cell and the outer substrate, thereby preventing the liquid crystal cell from being squeezed and overflowing.

[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 example, 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 example, 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 example, 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 simultaneously, 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 Formula 1, L1 may refer to 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 refer to the shortest linear distance 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 when a straight line is drawn between them. In Formula 1, L2 may refer to 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 refer to the shortest linear distance between any point on the outer periphery of the first outer substrate and any point on the outer periphery of the first intermediate layer when a straight line is drawn between them. Alternatively, L2 may refer to the shortest linear distance between any point on the outer periphery of the second outer substrate and any point on the outer periphery of the second intermediate layer when a straight line is drawn between them.

[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 stacked 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, where the longitudinal direction may refer to the direction parallel to the longest side of the quadrangle, and the width direction may refer to the direction parallel to the shortest side of the quadrangle. As used herein, "parallel" may mean that the directions, axes, or sides being evaluated form an angle of approximately 0 to 10 degrees, 0 to 5 degrees, 0 to 3 degrees, or approximately 0 degrees with respect to each other. As used herein, a rectangle may mean a shape in which the angles between its four vertices are approximately 80 to 100 degrees, 85 to 95 degrees, 93 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 sides, if the region satisfying Equation 1 exists on 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 in the above manner, if the region satisfying Equation 1 exists on 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 refer to the stacking direction of each component of the optical device or the thickness direction of the optical device, or may refer to a direction perpendicular to the planes 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 Equation 1 can exist on one side of a liquid crystal cell. When there is one region satisfying Equation 1, all regions on at least one side of the liquid crystal cell can satisfy Equation 1. For example, when there are n regions satisfying Equation 1, all regions on at least n sides of the liquid crystal cell can satisfy Equation 1.

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

[0021] When the optical device includes a region that does not satisfy Equation 1, the L1-L2 values ​​of Equation 1 for 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 excessively long, the active area in which the actual 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 depending on the shape and design of the product to be actually applied, as long as the object of the present application is not impaired.

[0023] When the optical device is viewed 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. This 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 at all of the outer peripheries of the first outer substrate and the second outer substrate. In other words, when the optical device is viewed 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 viewed 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. This 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 outer peripheries of the first intermediate layer and the second intermediate layer. In other words, when the optical device is viewed 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 example, 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 process of bonding with the outer substrate, thereby preventing the liquid crystal cell from being squeezed or 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 first base layer) may be located at the center of the first intermediate layer. Also, 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 second base layer) may be located at the center of the second intermediate layer.

[0027] In one example, the width x height of the liquid crystal cell can be appropriately selected depending on the intended use of the optical device. For example, the width of the liquid crystal cell can be in the range of 100 mm to 5000 mm, and the height can be in the range of 100 mm to 5000 mm.

[0028] The first and second intermediate layers may 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 refers to 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 each be an absorptive polarizer or a reflective polarizer. In this specification, an absorptive polarizer refers to an element that exhibits selective transmission and absorption properties for incident light. For example, an 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, a reflective polarizer refers to an element that exhibits selective transmission and reflection properties for incident light. For example, a 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. As used herein, a linear polarizer refers to a polarizer in which 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 stretched polymer film dyed with iodine or an anisotropic dye. An example of the stretched polymer film is a stretched PVA (poly(vinyl alcohol)) film. In another example, the first polarizer and the second polarizer may each be a guest-host polarizer, with a liquid crystal polymerized in an oriented state as the host and an anisotropic dye aligned by the orientation of the liquid crystal as the 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, a pressure-sensitive adhesive layer, an adhesive layer, a surface treatment layer, etc. may be additionally formed on one or both surfaces of the first polarizer and the second polarizer, respectively. Examples of materials for the protective film include thermoplastic resins with excellent transparency, mechanical strength, thermal stability, moisture barrier properties, or isotropy. Examples of such resins include cellulose resins such as triacetyl cellulose (TAC), 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 quarter-wave plate or a half-wave plate. The quarter-wave plate may have an in-plane retardation value for light with a wavelength of 550 nm within a range of about 100 nm to 180 nm, 100 nm, or 150 nm. The half-wave plate may have an in-plane retardation value in the 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 stretched polymer film or a liquid crystal polymer 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%. 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 can be measured, for example, using a spectrometer (V7100, manufactured by Jasco). For example, with a polarizer sample (excluding the upper and lower protective films) placed in the instrument, air is set to the baseline, and the axis of the polarizer sample is aligned vertically and horizontally with the axis of the reference polarizer, and the transmittance of each is measured, and then the single transmittance can be calculated.

[0036] When a polarizer is used in each of the first and second intermediate layers, the thickness of the polarizer may be in the range of 1 μm to 500 μm, and specifically, the thickness of the polarizer may be 30 μm or more, 50 μm or more, 70 μm or more, or 90 μm or more, and 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, an anisotropic dye, or a 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 polymer film laminate may refer to a structure in which two or more polymer films are stacked. In one example, the polymer film may include at least one selected from the group consisting of TAC (triacetyl cellulose) film, DAC (diacetyl cellulose) film, COP (cycloolefin copolymer) film, PA (Polyacrylate) film, PMMA (poly(methyl methacrylate) film, PC (polycarbonate) film, PE (polyethylene) film, PP (polypropylene) film, PVA (polyvinyl alcohol) film, PI (polyimide) film, PSF (polysulfone) film, PPS (polyphenylsulfone) film, PES (polyethersulfone) film, PEEK (polyetheretherketon) film, PEI (polyetherimide) film, PEN (polyethylenenaphthate) film, and PET (polyethyleneterephtalate) film.

[0038] When the first and second intermediate layers are each made of 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 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 made of a polymer film laminate, the thickness of the entire laminate may be within the above range.

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

[0040] In one example, 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 outer substrate and the second outer substrate 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 both be flat or curved, or one may be flat and the other curved. If both are curved, their curvatures or radii of curvature may be the same or different. The curvatures or radii of curvature herein may be measured using methods known in the art, such as non-contact equipment such as a 2D profile laser sensor, a chromatic confocal line sensor, or a 3D measuring confocal microscope. Methods for measuring the curvatures or radii of curvature using such equipment are well known.

[0043] The width and length of the first outer substrate and / or the second outer substrate may be appropriately selected taking into consideration the optical device to which it is applied. In one example, the width 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 greater than the width of the liquid crystal cell. In another example, the 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 greater than the length of the liquid crystal cell. The difference between the width of the first outer substrate and / or the second outer substrate and the width 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 the process of bonding with the outer substrate, thereby resolving the phenomenon of the liquid crystal cell being squeezed and overflowing.

[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 positioned 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 is 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 viewed 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 viewed in a normal direction, the areas of the first outer substrate and the second outer substrate may be substantially identical. When the optical device is viewed in a normal direction, the area of ​​the first intermediate layer may be substantially identical to the area of ​​the first outer substrate and / or the second outer substrate. The areas 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 areas 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 each be higher than the storage modulus of the pressure-sensitive adhesive layer included in the liquid crystal cell. Furthermore, the loss modulus of the first adhesive layer, the second adhesive layer, the third adhesive layer, and / or the fourth adhesive layer may each be higher than the loss modulus of the pressure-sensitive 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 pressure-sensitive adhesive layer, this may be advantageous in reducing 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 25°C and a frequency of 1 Hz may each be within the range of 1 MPa to 100 MPa. Specifically, the storage modulus may be 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 25°C and a frequency of 1 Hz may each be within the range of 1 MPa to 100 MPa. Specifically, the loss modulus may be 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] For 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 in the range of 0.1 MPa to 100 MPa. In other examples, 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) can be measured, for example, according to the method specified in ASTM D882. The film can be cut into the shape specified in the standard and measured using equipment capable of measuring stress-strain curves (capable of simultaneously measuring force and length), such as 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] For 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 specifications of ASTM D696. The thermal expansion coefficient can be calculated by cutting the adhesive layer into the shape specified in the relevant standard and measuring the change in length per unit temperature. It can also be measured 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. When 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 each be a thermoplastic polyurethane (TPU) adhesive layer, a polyamide adhesive layer, a polyester adhesive layer, an ethylene vinyl acetate (EVA) 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 each be a thermoplastic polyurethane adhesive layer.

[0056] For 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 refer to the sum of the thicknesses of all adhesive layers included in the optical device, for example, the first, second, third, and fourth adhesive layers. A total thickness of the adhesive layers within this range may be advantageous in minimizing defects during the bonding process of the outer substrates, thereby ensuring the structural stability and uniform appearance characteristics of the optical device. Specifically, the sum of the total thicknesses of the adhesive layers may be 1,500 μm or more, approximately 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 approximately 2,200 μm or more. The sum of the total thicknesses of the adhesive layers can 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 the electro-optical properties, such as the transmittance properties, of the optical device, so it may be advantageous for the thickness 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 a single adhesive layer or sub-intermediate layer 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 between 80 and 100 degrees or between 85 and 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 each 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 depending on the distance between the first and second polarizers. However, by setting the thickness of the second adhesive layer and the third adhesive layer within the above range, the distance between the first and second polarizers can be minimized, thereby reducing light leakage and ensuring the structural integrity of the liquid crystal cell. The lower limit of the thickness of the second adhesive layer and the third adhesive layer may each be 10 μm or more.

[0059] An example of a liquid crystal cell is shown in Figure 2. As shown in Figure 2, the liquid crystal cell may include a first substrate layer 10a, an adhesive layer 10c formed on the inner surface of the first substrate layer, a second substrate layer 20a disposed opposite the first substrate layer 10a, spacers 20c formed on the inner surface of the second substrate layer 20a, and a liquid crystal layer 30 positioned between the first substrate layer 10a and the second substrate layer 20a.

[0060] The first and second substrate layers may be made of 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 to realize a flexible device.

[0061] In one example, the first substrate layer and the second substrate layer may each be a polymer film. Examples of polymer films that can be used include, but are not limited to, 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); polyethylene mapthlate (PEN); polyethyleneterephthlate (PET); polyimide (PI); polysulfone (PSF); polyarylate (PAR), and amorphous fluororesin. The first substrate layer and the second substrate layer may optionally have a coating layer such as gold, silver, or a silicon compound such as silicon dioxide or silicon monoxide, or an anti-reflection layer.

[0062] The first and second substrate layers may each have a thickness of about 10 μm to about 1,000 μm. In other examples, 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 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 satisfy the above ranges, appearance defects 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 a range of 0.2 MPa to 10 MPa. Specifically, the storage modulus of the pressure-sensitive adhesive layer may be 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 a range of 0.5 MPa to 2 MPa. Specifically, the loss modulus of the pressure-sensitive adhesive layer may be 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 elastic 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, while if the elastic modulus of the pressure-sensitive adhesive layer inside the liquid crystal cell is too high, it may be difficult to provide adhesive effect. Therefore, it is advantageous for the elastic modulus to be within the above range. In one example, the storage modulus of the pressure-sensitive adhesive layer may be lower than the loss modulus.

[0065] The pressure-sensitive adhesive layer may be optically transparent, having 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. Herein, a "vertically aligning adhesive" may refer to an adhesive that imparts vertical alignment force to adjacent liquid crystal compounds and has adhesive strength capable of bonding an upper substrate and a lower substrate. Herein, a "horizontally aligning adhesive" may refer to an adhesive that imparts horizontal alignment force to adjacent liquid crystal compounds and has adhesive strength 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 to 90 degrees, 85 to 90 degrees, or about 87 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 to 10 degrees, 0 to 5 degrees, or 0 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 a plane horizontal to the liquid crystal alignment adhesive or alignment film 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 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 in minimizing 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). These adhesives may differ from OCR (Optically Clear Resin) adhesives, which harden after the objects are bonded, in that they harden before the objects are bonded. Examples of adhesives that may be used include acrylic, silicone, epoxy, and urethane adhesives.

[0070] The adhesive layer may include a cured adhesive resin. In one example, the adhesive layer may include a silicone-based adhesive. The silicone-based adhesive may include a cured silicone compound as the adhesive resin.

[0071] The type of 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, examples of the addition-curable silicon compound include, but are not limited to, (1) organopolysiloxanes containing two or more alkenyl groups in the molecule and (2) organopolysiloxanes containing two or more silicon-bonded hydrogen atoms in the molecule. Such silicon compounds can form cured products by addition reaction, for example, in the presence of a catalyst described below.

[0074] More specific examples of the organopolysiloxane (1) that can be used in the present application include a dimethylsiloxane-methylvinylsiloxane copolymer having both branched chain ends capped with trimethylsiloxane groups, a methylvinylpolysiloxane having both branched chain ends capped with trimethylsiloxane groups, a dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymer having both branched chain ends capped with trimethylsiloxane groups, a dimethylpolysiloxane having both branched chain ends capped with dimethylvinylsiloxane groups, a methylvinylpolysiloxane having both branched chain ends capped with dimethylvinylsiloxane groups, a dimethylsiloxane-methylvinylsiloxane copolymer having both branched chain ends capped with dimethylvinylsiloxane groups, a dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymer having both branched chain ends capped with dimethylvinylsiloxane groups, and 1 2SiO 1 / 2 The siloxane unit represented by R 1 2nd Round 2 SiO 1 / 2 The siloxane unit represented by SiO 4 / 2 Organopolysiloxane copolymers containing siloxane units represented by R 1 2nd Round 2 SiO 1 / 2 The siloxane unit represented by SiO 4 / 2 Organopolysiloxane copolymers containing siloxane units represented by R 1 R 2 SiO 2 / 2 The siloxane unit represented by R 1 SiO 3 / 2 Siloxane units denoted by R 2 SiO 3 / 2Examples of suitable organopolysiloxanes include, but are not limited to, organopolysiloxane copolymers containing siloxane units represented by the formula: 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, and specifically may be 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 whose branched chains are capped at both ends with trimethylsiloxane groups, dimethylsiloxane-methylhydrogen copolymers whose branched chains are capped at both ends with trimethylsiloxane groups, dimethylsiloxane-methylhydrogensiloxane-methylphenylsiloxane copolymers whose branched chains are capped at both ends with trimethylsiloxane groups, dimethylpolysiloxanes whose branched chains are capped at both ends with dimethylhydrogensiloxane groups, dimethylsiloxane-methylphenylsiloxane copolymers whose branched chains are capped at both ends with dimethylhydrogensiloxane groups, methylphenylpolysiloxanes whose branched chains are capped at both ends with dimethylhydrogensiloxane groups, R 1 3SiO 1 / 2 The siloxane unit represented by R 1 2HSiO 1 / 2 The siloxane unit represented by SiO 4 / 2 Organopolysiloxane copolymers containing siloxane units represented by R 1 2HSiO 1 / 2 The siloxane unit represented by SiO 4 / 2 Organopolysiloxane copolymers containing siloxane units represented by R 1 HSiO 2 / 2 The siloxane unit represented by R 1SiO 3 / 2 Siloxane units denoted by HSiO 3 / 2 Examples of suitable organopolysiloxanes include, but are not limited to, organopolysiloxane copolymers containing siloxane units represented by the formula: 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, and specifically may be a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, or the like.

[0076] In one example, 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 surface energy of the adhesive layer may be, for example, 5 mN / m or more. In another example, 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 can be measured using a drop shape analyzer (DSA100 product from KRUSS). Specifically, deionized water with a known surface tension is dropped onto the surface of the adhesive, and the contact angle is measured five times. The average of the five contact angle values ​​is then calculated. Similarly, diiodomethane with a known surface tension is dropped onto the surface of the adhesive, and the contact angle is measured five times. The average of the five contact angle values ​​is then calculated. The surface energy was then calculated by substituting the Strom value for the surface tension of the solvent using the Owens-Wendt-Rabel-Kaelble method using the average contact angles for deionized water and diiodomethane. The surface energy (γsurface) of a sample can be calculated by taking into account the dispersion force between nonpolar molecules and the interaction force between polar molecules (γsurface = γdispersion + γpolar), and the ratio of the polar term (γpolar) to 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 spacers of the lower substrate. When an alignment film is formed on the spacers of the lower substrate, the areas of the alignment film corresponding to the spacers 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 force. As used herein, the term "external force" may refer to any external factor, 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 force may refer to a state in which an external voltage or the like is not applied.

[0079] The type and properties of the liquid crystal compound may be appropriately selected taking into consideration the purpose of the present application. For 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 aligned parallel to the long axis direction of the liquid crystal molecules without any regularity in terms of their positions, while 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 aligned parallel to the long axis direction with regularity. 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 higher, 50° C. or higher, 60° C. or higher, 70° C. or higher, 80° C. or higher, 90° C. or higher, 100° C. or higher, or about 110° C. or higher, 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 lower, 150° C. or lower, or about 140° C. or lower.

[0081] The liquid crystal compound may be a non-reactive liquid crystal compound. The non-reactive liquid crystal compound may refer to a liquid crystal compound that does not have a polymerizable group. Examples of the polymerizable group include, but are not limited to, an acryloyl group, an acryloyloxy group, a methacryloyl group, a methacryloyloxy group, a carboxy group, a hydroxy group, a vinyl group, and an epoxy group. The polymerizable group may include known functional groups known as polymerizable groups.

[0082] The dielectric anisotropy of a liquid crystal compound may be positive or negative. The absolute value of the dielectric anisotropy of a liquid crystal compound may be appropriately selected taking into account the objectives of this application. The term "dielectric anisotropy (Δε)" may refer to the difference (ε / / -ε⊥) between the horizontal dielectric constant (ε / / ) and the vertical dielectric constant (ε⊥) of a liquid crystal. As used herein, the term "horizontal dielectric constant (ε / / )" refers to the dielectric constant measured along the direction of an electric field when a voltage is applied such that the direction of the electric field is substantially horizontal to the director of the liquid crystal compound, and the term "vertical dielectric constant (ε⊥)" refers to the dielectric constant measured along the direction of the electric field when a voltage is applied such that the direction of the electric field is substantially perpendicular to the director of the liquid crystal compound. The dielectric anisotropy of a liquid crystal compound may be in the range of 5 to 25.

[0083] The refractive index anisotropy (Δn) of a liquid crystal compound can be appropriately selected taking into consideration 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 containing a liquid crystal compound) 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 variations in the cell gap during the bonding process of the outer substrates, which has the advantage that the thickness of the intermediate layer, which ensures the structural stability and 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 characteristics of the liquid crystal layer. As used herein, the term "dye" may refer to a substance that can intensively absorb and / or transform light in at least a portion or all of the visible light range, e.g., the wavelength range of 400 nm to 700 nm, and the term "dichroic dye" may refer to a substance that can anisotropically absorb light in at least a portion or all of the visible light range.

[0086] A liquid crystal layer containing a liquid crystal compound and a dichroic dye may be a GHLC (guest-host liquid crystal layer). In this specification, the term "GHLC (guest-host liquid crystal layer)" refers to a functional layer in which the dichroic dye is aligned with the alignment of the liquid crystal compound, exhibiting anisotropic light absorption characteristics in both the alignment direction of the dichroic dye and the direction perpendicular to the alignment direction. For example, a dichroic dye is a material whose light absorption rate varies depending on the polarization direction. If it has a high absorption rate for light polarized along its long axis, it is called a p-type dye, and if it has a high absorption rate for light polarized along its short axis, it is called an n-type dye. For example, when a p-type dye is used, polarized light vibrating along the long axis of the dye is absorbed, while polarized light vibrating along the short axis of the dye is transmitted due to low absorption. Hereinafter, unless otherwise specified, the dichroic dye is assumed to be a p-type dye.

[0087] As the dichroic dye, for example, a known dye that is known to have the property of being able to align according to the alignment state of the liquid crystal compound due to 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 these.

[0088] The dichroic ratio of the dichroic dye, i.e., the absorbance of light polarized parallel to the long axis of the dichroic dye divided by the absorbance of light polarized perpendicular to the long axis, may be 5 or more, 6 or more, or 7 or more. The dye may satisfy this dichroic ratio at at least some wavelengths or any one wavelength within the wavelength range of the visible light region, for example, 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 taking into account the objectives of the present application. For example, the content of the dichroic dye in the liquid crystal layer may be 0.2 wt % or more. Specifically, the content of the dichroic dye may be 0.5 wt % or more, 1 wt % or more, 2 wt % or more, or 3 wt % or more. The upper limit of the dichroic dye content 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 characteristics and may be insufficient to reduce the thickness of the intermediate layer to reduce fluctuations in the cell gap that may occur during the outer substrate bonding process. On the other hand, if the content of the dichroic dye in the liquid crystal layer is too high, precipitation may occur. Therefore, it is 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 may be, for example, 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 may generally 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 spacers.

[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 external energy such as a voltage. For example, the liquid crystal layer can maintain one of the first and second alignment states when no voltage is applied, and can be switched to the other alignment state when a voltage is applied.

[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 alignment state and a homeotropic alignment state, and in one example, the liquid crystal layer can be in a homeotropic state when no voltage is applied and in a twisted alignment state when a voltage is 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 formed by the directors of the liquid crystal compound with respect to the plane of the liquid crystal layer can be, for example, within the range of approximately 80 degrees to 100 degrees or 85 degrees to 95 degrees, or can be approximately 90 degrees.

[0095] As used herein, the term "twisted alignment state" refers to a helical structure in which the directors of liquid crystal compounds in a liquid crystal layer are twisted along a virtual helical axis to form layers. The twisted alignment state can be realized 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 layers, 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 layers, 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 layers. According to the present application, the twisted alignment state can be a twisted alignment state of a horizontal alignment state.

[0096] In the twisted alignment state, the ratio (d / p) of the liquid crystal layer thickness d to the pitch p can 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 this range, the optical device can exhibit excellent light transmittance tunability even without a polarizer. Typically, when the ratio d / p is 0.7 or more but less than 2.5, it can be called an STN (Super Twisted Nematic) mode, and when the ratio d / p is 2.5 or more, it can be called an 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 can be realized. The chiral agent (or chiral dopant) that can be included in the liquid crystal layer is not particularly limited, as long as it can induce the desired twisting without damaging the liquid crystal properties, e.g., nematic regularity. A chiral agent that induces rotation in a liquid crystal compound must at least have chirality in its molecular structure. Examples of chiral agents include compounds with one or more asymmetric carbons, compounds with an asymmetric point on a heteroatom, such as chiral amines or chiral sulfoxides, or compounds with an axially asymmetric, optically active site, such as cumulene or binaphthol. The chiral agent may be a low-molecular-weight compound with 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 ratio of the chiral dopant to be applied is selected to achieve the desired ratio (d / p). Generally, the content (wt%) of the chiral dopant can be calculated by the formula: 100 / HTP (Helixcal Twisting Power) × 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 the desired pitch into consideration using this 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 and second electrode layers may act on the liquid crystal layer by applying an external force, such as an electric field, to allow the material contained in the liquid crystal layer to transmit or block incident light. For example, the first and / or second electrode layers may include, but are not limited to, a conductive polymer, a conductive metal, a conductive nanowire, or a metal oxide such as ITO (Indium Tin Oxide). The first and / or second electrode layers may be formed by depositing 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 and / or side surfaces 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. Because 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 substrate layer, the first electrode layer, and the adhesive layer may be referred to as an upper substrate, and the combination of the second substrate 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 substance that imparts 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 substance that imparts vertical alignment force to the liquid crystal compound present in the adjacent liquid crystal layer. The pretilt angle of the adjacent liquid crystal compound relative to the vertical alignment film may be within a range of 80 to 90 degrees, 85 to 90 degrees, or approximately 87 to 90 degrees, and the pretilt angle of the adjacent liquid crystal compound relative to the horizontal alignment film may be within a range of 0 to 10 degrees, 0 to 5 degrees, or 0 to 3 degrees. Unlike the adhesive layer, the alignment film may not have adhesive strength to bond the upper and lower substrates. In one example, the peel strength of the alignment film relative to the upper substrate may be close to zero in the state of the liquid crystal cell shown in FIG. 2.

[0105] The alignment film may be a rubbed alignment film or a photo-aligned film. The alignment direction of the alignment film may be the rubbing direction in the case of a rubbed alignment film, or the direction of polarized light in the case of a photo-aligned film. This alignment direction can be confirmed by a detection method using an absorptive linear polarizer. Specifically, the alignment direction can be confirmed by placing an absorptive linear polarizer on one side of the liquid crystal layer with the liquid crystal compound contained in the liquid crystal layer horizontally aligned and measuring the transmittance while rotating the polarizer 360 degrees. In this state, when light is irradiated onto the liquid crystal layer or the absorptive linear polarizer and the brightness (transmittance) is measured from 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. However, the alignment direction can be confirmed by simulation that reflects the refractive index anisotropy of the applied liquid crystal compound. Methods for determining the alignment direction depending on the mode of the liquid crystal layer are well known, and the alignment direction of the alignment film can be confirmed using such a known method in this application.

[0106] Examples of the alignment film include materials known to exhibit alignment ability through rubbing alignment, such as polyimide compounds, poly(vinyl alcohol) compounds, poly(amic acid) compounds, polystyrene (polystylene) 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, polyamide compounds, polyethylene compounds, polystyrene (polystylene) compounds, polyphenylenephthalamide compounds, polyester compounds, and 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 (polyvinyl cinnamate) compound, and a polymethyl methacrylate compound.

[0107] The spacers 20c can maintain the distance between the upper and lower substrates, and the liquid crystal layer can exist in the area where there are no spacers between the upper and lower substrates.

[0108] The spacers may be patterned. The spacers may have a column or partition wall shape. The partition walls may divide the space between the lower and upper substrates into two or more spaces. In areas where there are no spacers, other films or layers present underneath may be exposed. For example, the second electrode layer may be exposed in areas where there are no spacers. An alignment film may cover the spacers and the second electrode layer exposed in areas where there are no spacers. In a liquid crystal cell in which the upper and lower substrates are bonded together, the alignment film present on top of the spacers 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 any shape, such as a circle, ellipse, or other polygonal shape, with multiple faces.

[0110] The spacer may include a curable resin. The type of curable resin is not particularly limited, and may be, for example, a thermosetting resin or a photocurable resin, such as a UV-curable resin. Examples of thermosetting resins that may be used include, but are not limited to, silicone resins, silicon resins, furan resins, polyurethane resins, epoxy resins, amino resins, phenolic resins, urea resins, polyester resins, and melamine resins. Examples of UV-curable resins that may be used include, but are not limited to, acrylic polymers, such as polyester acrylate polymers, polystyrene acrylate polymers, epoxy acrylate polymers, polyurethane acrylate polymers, polybutadiene acrylate polymers, silicone acrylate polymers, and alkyl acrylate polymers.

[0111] The spacers may be formed by a patterning process. For example, the spacers may be formed by a photolithography process. The photolithography process may include a process of applying a curable resin composition to a substrate layer or an electrode layer and then irradiating it with ultraviolet light using a pattern mask. The pattern mask may be patterned with ultraviolet-transmitting and ultraviolet-blocking regions. The photolithography process may further include a process of washing the curable resin composition irradiated with ultraviolet light. The areas irradiated with ultraviolet light are cured, while the areas not irradiated with ultraviolet light remain liquid, which can be removed through a washing process to form a partition wall pattern. In the photolithography process, to easily separate the resin composition from 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 resin composition layer and the pattern mask.

[0112] The width (line width), spacing (pitch), height (thickness), and area of ​​the spacers may be appropriately selected within a range that does not impair the objectives of the present application. For example, the width (line width) of the spacers may be in the range of 10 μm to 500 μm or 10 μm to 50 μm. The spacing (pitch) of the spacers may be in the range of 10 μm to 1000 μm or 100 μm to 1000 μm. The area of ​​the spacers may be approximately 5% or more and 50% or less of the total area of ​​the second substrate layer (100%). When the area of ​​the spacers is within the above range, it may be advantageous to ensure excellent electro-optical properties while adequately ensuring adhesion between the upper and lower substrates. The height (thickness) of the spacers 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 to fourth adhesive layers and the outer layer. In this application, the term "encapsulation" may refer to covering the entire surface of the liquid crystal cell with the adhesive layers and the outer layer. Depending on the desired structure, the encapsulation structure may be realized by vacuum-pressing a laminate including, in order, 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, and an outer layer surrounding the sides of the liquid crystal cell. This encapsulation structure significantly improves the durability and weather resistance of the optical device, making it suitable for 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 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 liquid crystal cell thickness B1 may refer to the sum of the thickness of the first substrate layer, the thickness of the adhesive layer, the thickness of the liquid crystal layer (height of the spacer), and the thickness of the second substrate layer. That is, when discussing the liquid crystal cell thickness B1 in this specification, the thicknesses of the electrode layer and the alignment layer may be excluded because they are measured in nanometers. 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, or 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 may be 100,000 Pa or less. The storage modulus of the outer layer at 110°C and 1 Hz may be, specifically, 90,000 Pa or less, 80,000 Pa or less, 70,000 Pa or less, or 50,000 Pa or less, or 10,000 Pa or more, or 30,000 Pa or more. During the autoclave process for bonding 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 strong pressure may be applied to the edge region of the liquid crystal cell adjacent to the outer layer. As a result, uneven pressure may be concentrated in localized areas at the edge region of the liquid crystal cell, potentially causing cell gap collapse (pressure) and liquid crystal overflow during bonding of the outer substrates. The present application can solve these problems.

[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 the side of the liquid crystal cell, and autoclaving the laminate. Unless otherwise specified, the same details as those described for the optical device may be applied to the method for manufacturing the optical device.

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

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

[0124] The autoclave process conditions are not particularly limited and can be performed under appropriate temperature and pressure depending on the type of intermediate layer used. Typical autoclave processes are performed at temperatures of about 80°C or higher, 90°C or higher, or 100°C or higher, and at pressures of 2 atmospheres or higher, but are not limited thereto. The upper limit of the process temperature can be about 200°C or lower, 190°C or lower, 180°C or lower, or 170°C or lower, and the upper limit of the process pressure can be about 10 atmospheres or lower, 9 atmospheres or lower, 8 atmospheres or lower, 7 atmospheres or lower, or 6 atmospheres or lower.

[0125] The optical device may be used in a variety of applications, including, for example, eyewear such as sunglasses, augmented reality (AR) or virtual reality (VR) eyewear, building exterior walls, and vehicle sunroofs. In one example, the optical device may be a vehicle sunroof itself. For example, the optical device may be attached to at least one opening in a vehicle body having the vehicle body, or the vehicle sunroof may be attached to the opening. [Effects of the Invention]

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

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

[0128] [Figure 2] 1 shows an exemplary liquid crystal cell of the present application.

[0129] [Figure 3] 10 is an image showing the observed pressing and overflow defects after bonding of the optical device of Example 1.

[0130] [Figure 4] 10 is an image showing the observed pressing and overflow defects after bonding of the optical device of Comparative Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0131] The present application will be described in detail below through 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 approximately 145 μm and dimensions of 900 mm x 600 mm was prepared as the first substrate layer. A 50 nm thick ITO (indium-tin-oxide) film was vapor-deposited onto the first substrate layer to form a first electrode layer. An adhesive composition (KR-3700, Shin-Etsu Corporation) was coated onto the first electrode layer and dried at approximately 150°C for approximately 5 minutes to form an adhesive layer with a thickness of approximately 10 μm. The adhesive layer had a storage modulus of approximately 754,500 Pa at 25°C and a frequency of 1 Hz, and a loss modulus of approximately 906,687 Pa at 25°C and a frequency of 1 Hz. The combination of the first substrate layer, first electrode layer, and adhesive layer is referred to as the upper substrate.

[0135] A PET film (SK Corporation) with a thickness of approximately 145 μm and dimensions of 900 mm x 600 mm was prepared as the second substrate layer. A 50 nm thick ITO (indium-tin-oxide) layer was vapor-deposited on the second substrate layer to form the second electrode layer. An acrylic resin composition (KAD-03, Minutek) was then coated on the second electrode layer, and a honeycomb-shaped spacer was then formed using photolithography. The regular hexagons (closed shapes) that make up the honeycomb had a pitch of approximately 350 μm, a height of approximately 6 μm, and a line width of approximately 30 μm. A vertical alignment film (Nissan, 5661) was coated on the spacer to a thickness of approximately 300 nm and then rubbed in one direction. The combination of the second substrate layer, second electrode layer, spacer, and vertical alignment film is referred to as 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 facing the liquid crystal composition-coated surface to fabricate a liquid crystal cell. The liquid crystal composition contained a liquid crystal compound (JNC Corporation, SHN-5011XX) and a chiral dopant (HCCH Corporation, S811), and the liquid crystal layer pitch p was approximately 20 μm. The liquid crystal cell was an RTN mode liquid crystal cell with an initial vertical alignment state. The horizontal and vertical dimensions of the liquid crystal cell were 900 mm x 600 mm, and the thickness was approximately 306 μm.

[0137] Optical Device Manufacturing

[0138] A laminate including an outer layer surrounding the side of the liquid crystal cell was prepared, which sequentially included 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. The first base layer of the liquid crystal cell was positioned closer to the first outer substrate, and the second base layer of the liquid crystal cell was positioned closer to the second outer substrate. The second outer substrate was positioned in the direction of gravity compared to the first outer substrate.

[0139] The first and second outer substrates were each made of double-curved glass with a thickness of approximately 3 mm and an area of ​​1100 mm x 800 mm. The first, second, third, and fourth adhesive layers were each made of a TPU layer (Argotec) with a thickness of approximately 380 μm. The TPU layer (Argotec) had a storage modulus of 3,357,730 Pa at 25°C and 1 Hz and a loss modulus of 1,485,510 Pa at 25°C and 1 Hz. The outer layer was made of a TPU layer (Argotec) with a thickness of 380 μm. The TPU 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 made of a polarizer with a thickness of approximately 95 μm and an area of ​​960 mm x 600 mm (width x length). The polarizer was made of 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 atmospheres to fabricate an optical device.

[0141] When the optical device was observed in the normal direction, the liquid crystal cell area was included in the area of ​​the first intermediate layer and the area of ​​the second intermediate layer. When the optical device was observed in the normal direction, the area of ​​the first intermediate layer was included in the area of ​​the first outer substrate, and the area of ​​the second intermediate layer was included in the area of ​​the second outer substrate. When the optical device was observed in the normal direction, the areas of the first outer substrate and the second outer substrate were approximately the same. When the optical device was observed in the normal direction, the areas of the first intermediate layer and the second intermediate layer were approximately the same. In the optical device, the areas of the first adhesive layer to the fourth adhesive layer were approximately the same as the area of ​​the first outer substrate. When the optical device was observed in the normal direction, the difference (L1-L2) between the distance L1 between the outer edge of the first outer substrate and the outer edge of the liquid crystal cell and the distance L2 between the outer edge of the first outer substrate and the outer edge of the first intermediate layer was 30 mm (distance D1 based on the first outer substrate) on both sides (left and right) of the liquid crystal cell. Furthermore, when the optical device was observed in the normal direction, the difference (L1-L2) between the distance L1 between the outer edge of the second outer substrate and the outer edge of the liquid crystal cell and the distance L2 between the outer edge of the second outer substrate and the outer edge 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. 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. 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 fabricated in the same manner as in Example 1, except that polarizers with a horizontal length of 950 mm were used as the first and second intermediate layers, and 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 also changed to 25 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 75 mm.

[0146] Example 4

[0147] An optical device was fabricated in the same manner as in Example 1, except that polarizers with a horizontal length of 940 mm were used as the first and second intermediate layers, 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 also 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.

[0148] Example 5

[0149] The 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 for the first and second substrate layers. The width x length of the liquid crystal cell was 560 mm x 600 mm and the thickness was approximately 306 μm. The subsequent processes were performed identically to 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 fabricated in the same manner as in Example 1, except that a liquid crystal composition containing 2 wt% of a dichroic dye (BASF, X12) was used. Furthermore, instead of polarizers, PET films (including UV cut function) with a thickness of approximately 125 μm and an area of ​​940 mm x 600 mm were used as the first and second intermediate layers. An optical device was fabricated 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 also changed to 20 mm. 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 fabricated in the same manner as in Example 1, except that polarizers with a horizontal length of 930 mm were used as the first and second intermediate layers, and 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. 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 polarizers with a horizontal length of 920 mm were used as the first and second intermediate layers, and 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. 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 fabricated in the same manner as in Example 1, except that polarizers with a horizontal length of 920 mm were used as the first and second intermediate layers, thereby changing the distance L1-L2 from the outer edge of the first outer substrate to 10 mm, and the distance L1-L2 from the second outer substrate to 10 mm, and 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 cell to 224 μm. 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 fabricated in the same manner as in Example 1, except that polarizers with a horizontal length of 920 mm were used as the first and second intermediate layers, thereby changing the distance L1-L2 from the outer edge of the first outer substrate to 10 mm, and the distance L1-L2 from the second outer substrate to 10 mm, and a laminate of two 380 μm-thick TPU layers (Argotec) was used as the outer layer, thereby changing the difference in thickness between the outer layer and the liquid crystal cell to 454 μm. 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 fabricated in the same manner as in Example 1, except that polarizers with a horizontal length of 900 mm were used as the first and second intermediate layers, and 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. 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 due to pressing and overflow after bonding

[0163] The optical devices of Examples 1 to 6 and Comparative Examples 1 to 5 were evaluated for pressure and overflow defects after bonding of the outer substrates, and the results are shown in Table 1. Figure 3 is an image of the pressure and overflow defects observed after bonding of the optical device of Example 1, and Figure 4 is an image of the pressure and overflow defects observed after bonding of the optical device of Comparative Example 2. As shown in Figure 4, in Comparative Example 2, uneven pressure was applied to the edge, and liquid crystal deviation and overflow defects due to pressure were observed. Comparative Examples 1 and 3 to 5 also showed results similar to Comparative Example 2. In contrast, as shown in Figure 3, no such defects were observed in Example 1. Examples 2 to 6 also showed results similar 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 class 302: Second middle class 401: First adhesive layer 402: Second adhesive layer 403: Third adhesive layer 404: Fourth 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, in that order; the liquid crystal cell comprises 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 including at least one region that satisfies the following formula 1 and satisfies the following formula 2: One area means one side, [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 first base layer of the liquid crystal cell, or the distance between the second outer substrate and the outer periphery of the second base layer 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, [Formula 2] A1<A2<A3 In Equation 2, A1 is the area (unit: mm 2 ) of the first substrate layer or the second substrate layer of the liquid crystal cell, A2 is the area (unit: mm 2 ) of the first intermediate layer or the second intermediate layer, and A3 is the area (unit: mm 2 ) of the first outer substrate or the second outer substrate.

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

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 may be 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 a polyethylene terephthalate (PEK) film, a polyethylene alcohol (PEI) 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 polyethyleneterephthalate (PET) film.

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

8. L １ -L ２ The optical device of claim 1 , wherein is equal to or less than 200 mm.

9. 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.

10. The optical device of claim 1 , further comprising an outer layer surrounding the sides of the liquid crystal cell.

11. The optical device according to claim 10, 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).

12. 11. The optical device of claim 10, wherein the outer layer has a storage modulus of 100,000 Pa or less at a temperature of 110[deg.] C. and a frequency of 1 Hz.

13. The optical device according to claim 1 , wherein the liquid crystal layer switches its orientation state by application of a voltage.

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

15. The optical device of claim 14 , wherein the upper substrate does not include an alignment layer, and the lower substrate further includes an alignment layer.

16. 16. A motor vehicle comprising: a body having one or more openings formed therein; and an optical device according to any one of claims 1 to 15 mounted in said openings.

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