Liquid crystal cells and optical devices

Abstract

The present application relates to a liquid crystal cell and an optical device, which can properly maintain the cell gap of a liquid crystal element, have excellent adhesion between an upper substrate and a lower substrate, and can solve the problems of pressing and liquid crystal overflow that may occur during the bonding process of an outer substrate due to delamination that may occur during a post-electrode process.

Description

[Technical Field]

[0001] The present application relates to liquid crystal cells and optical devices.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0039632 filed on March 30, 2022, and all contents disclosed in the documents of the 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 in which a pillar- or wall-shaped organic film pattern is formed on one substrate at the cell gap height and then attached to the opposite substrate using an adhesive. 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 leak out 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, one approach is to form a spacer and alignment film on the lower substrate, and then form an adhesive layer on the upper substrate, which has both liquid crystal alignment and adhesive properties, before bonding them together. However, while liquid crystal is filled between the adhesive layer and the spacer in this liquid crystal cell, contamination of the interface between the adhesive layer and the spacer can result in a significant difference in adhesion between areas with and without liquid crystal, leading to problems such as delamination during post-electrode processing. Furthermore, during the process of bonding outer substrates to both sides of the liquid crystal cell, the delamination can cause pressure and overflow due to residual liquid crystal at the interface.

[0006] The object of the present application is to provide a liquid crystal cell and an optical device that can properly maintain the cell gap of the liquid crystal cell, have excellent adhesion between the upper and lower substrates, and solve the problems of pressing and liquid crystal overflow that may occur during the outer substrate bonding process due to interlayer delamination that may occur during the electrode post-processing process. [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 a liquid crystal cell. Figure 1 shows an example of the liquid crystal cell of the present application. The liquid crystal cell includes an upper substrate including a first base layer 10a and an adhesive layer 10c, and a lower substrate including a second base layer 20a and a spacer 20c. The region between the upper and lower substrates can be divided into a liquid crystal region 100 including a liquid crystal compound 30 and non-liquid crystal regions 200a and 200b not including the liquid crystal compound 30.

[0009] The non-liquid crystal region may be filled with air. The non-liquid crystal region may serve as a bezel for the liquid crystal cell. The liquid crystal cell of the present application can ensure processability of the liquid crystal cell and prevent defects during the outer substrate bonding process by controlling the width of the non-liquid crystal region. The width (W1 or W2) of the non-liquid crystal region may be 4 mm or more. In the region where liquid crystal is present between the upper and lower substrates, the adhesion between the upper and lower substrates is poor, which can easily cause the above-mentioned defects. According to the present invention, by ensuring the width of the non-liquid crystal region to be greater than a predetermined range, the appropriate adhesion between the upper and lower substrates of the liquid crystal cell can be ensured, thereby solving the problems of the present invention. Specifically, the width (W1 or W2) of the non-liquid crystal region may be 5 mm or more, 6 mm or more, 7 mm or more, 8 mm or more, 9 mm or more, or 10 mm or more. When the width (W1, W2) of the non-liquid crystal region is within the above range, it is possible to prevent liquid crystal squeezing and overflow defects that may occur during the outer substrate bonding process due to delamination that may occur during post-electrode processing. The width of the non-liquid crystal region (W1 or W2) can 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, 40 mm or less, 20 mm or less, or 15 mm or less.

[0010] The length of the non-liquid crystal region and the length of the liquid crystal region may be substantially the same as the length of the second substrate layer in the longitudinal direction. In one example, the difference (L1-L2) between the length (L1) of the non-liquid crystal region and the length (L2) of the liquid crystal region may be, for example, 10 mm or less, 5 mm or less, 3 mm or less, or 1 mm or less.

[0011] The non-liquid crystal regions may have a line shape extending in a first direction. The first direction may be the length (horizontal) direction of the first substrate layer and / or the second substrate layer. In this specification, the longitudinal direction of the first substrate layer and / or the second substrate layer may refer to a direction parallel to the longest side of the polygon when the plane of the first substrate layer and / or the second substrate layer has a polygonal shape. When all sides of the polygon have the same length, the longitudinal direction may refer to a direction parallel to any side of the polygon. In one example, the plane of the first substrate layer and / or the second substrate layer may have a quadrilateral, more specifically, a rectangular shape. In one example, when the plane of the first substrate layer and / or the second substrate layer is rectangular, the first direction may refer to the horizontal direction of the rectangle.

[0012] The non-liquid crystal regions may be located on either side of the liquid crystal region. The non-liquid crystal regions may be located on both sides of the liquid crystal region or on one side of the liquid crystal region. Figures 2 and 3 each show an example of a structure of a liquid crystal cell observed from above. That is, Figures 2 and 3 show an example of a structure of a liquid crystal cell observed from the upper substrate side with the lower substrate in contact with the bottom.

[0013] FIG. 2 illustrates an exemplary liquid crystal cell in which non-liquid crystal regions 200a and 200b are located on both sides of the liquid crystal region 100. As shown in FIG. 2, the non-liquid crystal regions may be located on the first and second sides of the liquid crystal region. When the liquid crystal cell is observed from above, the first non-liquid crystal region 200a, the liquid crystal region 100, and the second non-liquid crystal region 200b may be present in this order. In this case, the non-liquid crystal region 200a located on the first side of the liquid crystal region 100 and the non-liquid crystal region 200b located on the second side of the liquid crystal region 100 may not be in contact with each other. In this case, the non-liquid crystal region 200a located on the first side of the liquid crystal region 100 and the non-liquid crystal region 200b located on the second side of the liquid crystal region 100 may be parallel to each other. The widths of the non-liquid crystal regions 200a and 200b may each be within the above ranges. In one example, the widths of the non-liquid crystal regions 200a and 200b may be the same.

[0014] 3 exemplarily illustrates a liquid crystal cell in which a non-liquid crystal region 200 is located on one side of a liquid crystal region 100. As shown in FIG. 3, the non-liquid crystal region may be located on only one side of the liquid crystal region. When the liquid crystal cell is observed from above, the liquid crystal region 100 and the non-liquid crystal region 200 may be present in this order.

[0015] The method for forming the liquid crystal region and the non-liquid crystal region between the upper and lower substrates is not particularly limited. For example, a liquid crystal layer may be formed in the region corresponding to the liquid crystal region on the lower substrate, and the upper substrate may be bonded without forming a liquid crystal layer in the region corresponding to the non-liquid crystal region.

[0016] The liquid crystal cell may be stacked with the upper and lower substrates alternately arranged. For example, as shown in FIG. 1, a region where only one of the upper and lower substrates is present may be present on a side of a non-liquid crystal region. A conductive tape 400a, 400b extending in a first direction may be formed on one of the substrates. FIG. 2 exemplarily shows a region 300a where only one of the upper and lower substrates is present and a region 300b where only the other of the upper and lower substrates is present at both ends of the liquid crystal cell. Here, the region where only the upper substrate is present at the end of the liquid crystal cell may be referred to as a region where the upper substrate is exposed, and the region where only the lower substrate is present at the end of the liquid crystal cell may be referred to as a region where the lower substrate is exposed.

[0017] 2 exemplarily shows a structure including both regions 300a and 300b. Meanwhile, FIG. 3 exemplarily shows region 300, where only one of the upper and lower substrates is present at one end of the liquid crystal cell. In this case, conductive tape 400 may be formed on region 300. The conductive tape may serve to conduct electricity so that the liquid crystal cell can be driven uniformly. The width of the conductive tape may be, for example, within a range of 1 mm to 200 mm.

[0018] 4 illustrates the configuration of the liquid crystal cell in more detail by illustrating the liquid crystal region of the liquid crystal cell. The following descriptions regarding the first substrate layer, first electrode layer, adhesive layer, second substrate layer, second electrode layer, spacer, and alignment film may be applied to the non-liquid crystal region of the liquid crystal cell, the region where the upper substrate is exposed, and / or the region where the lower substrate is exposed.

[0019] As mentioned above, the upper substrate of the liquid crystal cell may include a first substrate layer 10a, and the lower substrate may include a second substrate layer 20a.

[0020] The first and second substrate layers may be made of inorganic films such as glass films, crystalline or amorphous silicone films, quartz or ITO (Indium Tin Oxide) films, or polymer films, and a polymer film may be used to realize a flexible device.

[0021] 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.

[0022] The thickness of the first substrate layer and the second substrate layer may each be about 10 μm to about 1,000 μm. In other examples, the thickness of the first substrate layer and the second substrate layer may each be 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 thickness of the first substrate layer and the second substrate layer satisfies the above range, it may be advantageous to reduce appearance defects such as wrinkles when bonding the liquid crystal cell to an outer substrate to manufacture an optical device.

[0023] In the upper substrate, the adhesive layer 10c may be present on the inner surface of the first base layer 10a. 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 (the layer in which the liquid crystal compound is present).

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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 gathering of the adhesive when used in manufacturing a liquid crystal cell while ensuring adhesion between the upper and lower substrates.

[0029] The adhesive layer may be made of various types of adhesives known in the industry as optically clear adhesives (OCA). These adhesives may differ from optically clear resin (OCR) adhesives, which cure before the objects are bonded, by being cured after they are bonded. Examples of the adhesives that may be used include acrylic, silicone, epoxy, and urethane adhesives.

[0030] 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.

[0031] 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.

[0032] In one example, the curable silicone compound can be an addition-cure silicone compound.

[0033] Specifically, examples of the addition-curable silicone 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 silicone compounds can form cured products by addition reaction, for example, in the presence of a catalyst described below.

[0034] 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 / 2 Examples of suitable organopolysiloxanes include, but are not limited to, organopolysiloxane copolymers containing siloxane units represented by the formula: 1is 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.

[0035] 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 1 SiO 3 / 2 Siloxane units denoted by HSiO 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.

[0036] 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 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 may 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 angles 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 angles 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.

[0037] 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.

[0038] The liquid crystal region may be referred to as an active area. The liquid crystal compound in the liquid crystal region can switch its alignment state by applying a voltage. The liquid crystal compound may be a liquid crystal compound whose alignment direction can be changed by applying 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 no external voltage or the like is applied.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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 the present 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.

[0043] 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.

[0044] The liquid crystal layer (the layer containing the liquid crystal compound) may further contain a dichroic dye. When the liquid crystal layer contains a dichroic dye, even if the liquid crystal cell includes an adhesive layer, the liquid crystal cell is less affected by fluctuations in the cell gap during the process of bonding the outer substrates, which has the advantage that the thickness of the intermediate layer, which ensures the structural stability and quality uniformity of the liquid crystal cell, can be made relatively thin.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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).

[0062] 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.

[0063] 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.

[0064] The alignment film and the liquid crystal layer may be in contact with each other. The alignment film may be a vertical alignment film or a horizontal alignment film. In this specification, the term "horizontal alignment film" may refer to a layer containing an alignment material that imparts horizontal alignment force to the liquid crystal compound present in the adjacent liquid crystal layer. In this specification, the term "vertical alignment film" may refer to a layer containing an alignment material that imparts 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°, 85° to 90°, or approximately 87° to 90°, 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°, 0° to 5°, or 0° to 3°. 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. 4.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] The spacer-free region between the upper and lower substrates may contain the liquid crystal compound 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, having multiple faces.

[0070] 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 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 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.

[0071] 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.

[0072] 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.

[0073] The present application relates to an optical device. The optical device of the present application may include a first outer substrate, a liquid crystal cell, and a second outer substrate, in that order. In this case, the upper substrate of the liquid crystal cell may be disposed close to the first outer substrate, and the lower substrate of the liquid crystal cell may be disposed close to the second outer substrate.

[0074] 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.

[0075] 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 base layer and / or the second base layer.

[0076] 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.

[0077] 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.

[0078] In one example, the first outer substrate and the second outer substrate may each be a double-curved substrate. The autoclave process, which will be described later, is performed under process conditions such as reduced pressure, increased pressure, or increased pressure. The double-curved surfaces of the outer substrates may generate uneven stress. In particular, under reduced pressure, if the adhesion between the upper and lower substrates is weak, delamination may occur. The delamination may cause the liquid crystal to flow and cause overflow defects. This defect is particularly likely to occur in the region where the liquid crystal is present between the upper and lower substrates, where the adhesion is poor. However, according to the present invention, this defect can be resolved by ensuring that the width of the non-liquid crystal region is greater than a predetermined range.

[0079] 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.

[0080] In one example, the optical device may further include a first adhesive layer between the first outer substrate and the liquid crystal cell and a second adhesive layer between the second outer substrate and the liquid crystal cell. 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 liquid crystal cell. One side of the second adhesive layer may be in direct contact with the second outer substrate, and the other side may be in direct contact with the liquid crystal cell. 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 layer between them.

[0081] In one embodiment, the optical device may further include at least one intermediate layer positioned between the first outer substrate and the liquid crystal cell and between the second outer substrate and the liquid crystal cell. The intermediate layer may be, for example, a polarizer. In another embodiment, the optical device may include a first polarizer positioned between the first outer substrate and the liquid crystal cell and a second polarizer positioned between the second outer substrate and the liquid crystal cell. When the optical device further includes a first polarizer and a second polarizer, the optical device may further include a first adhesive layer between the first outer substrate and the first polarizer, a second adhesive layer between the first polarizer and the liquid crystal cell, a third adhesive layer between the liquid crystal cell and the second polarizer, and a fourth adhesive layer between the second polarizer and the second outer substrate. In this case, 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 polarizer. One side of the second adhesive layer may be in direct contact with the first polarizer, 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 polarizer. One side of the fourth adhesive layer may be in direct contact with the second polarizer, and the other side may be in direct contact with the second outer substrate.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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. Examples of materials for the protective film include thermoplastic resins with excellent transparency, mechanical strength, thermal stability, moisture barrier properties, and 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.

[0087] 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.

[0088] When the first intermediate layer and the second intermediate layer include a first polarizer and a second polarizer, respectively, the light transmission axis of the first polarizer and the light transmission axis of the second polarizer may be perpendicular to each other. Specifically, the angle between the light transmission axis of the first polarizer and the light transmission axis of the second polarizer may be within a range of 80 to 100 degrees or 85 to 95 degrees. In this case, the thickness of the second adhesive layer between the first intermediate layer and the liquid crystal cell and the third adhesive layer between the second intermediate layer and the liquid crystal cell may 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 polarizer and the second polarizer. However, by setting the thickness of the second adhesive layer and the third adhesive layer within the above range, the distance between the first polarizer and the second polarizer can be minimized, 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.

[0089] 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. When 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, appearance defects can be reduced even under durable conditions.

[0090] In one example, the storage modulus of the first adhesive layer, the second adhesive layer, the third adhesive layer, and / or the fourth adhesive layer at a temperature of 25°C and a frequency of 1 Hz may 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 a temperature of 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.

[0091] 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.

[0092] 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 intermediate 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.

[0093] 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.

[0094] 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, if the optical device includes a first adhesive layer and a second adhesive layer, the sum of the thicknesses of the adhesive layers may refer to the sum of the thicknesses of the adhesive layers. For example, if the optical device includes a first adhesive layer, a second adhesive layer, a third adhesive layer, and a fourth adhesive layer, the sum of the thicknesses of the adhesive layers may refer to the sum of the thicknesses of the adhesive layers. When the total thickness of the adhesive layers is within the above range, defects during the bonding process of the outer substrates can be minimized, thereby ensuring the structural stability and uniform appearance characteristics of the optical device. The sum of the total thicknesses of the adhesive layers may be specifically 500 μm or more, 1,000 μm or more, 1,500 μm or more, or 2,000 μm or more. The sum of the total thicknesses of the adhesive layers may be, for example, about 6,000 μm or less, 5,000 μm or less, 4,000 μm or less, or 3,000 μm or less. If the total thickness of the adhesive layer is excessively thick, it may deteriorate the electro-optical properties, such as the transmittance properties, of the optical device, so it may be advantageous for the total thickness to be within the above range.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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. The physical properties of the outer layer may be the same as those described for the first and second adhesive layers.

[0099] The present application also relates to a method for manufacturing an optical device.

[0100] In one example, when the optical device does not include a polarizer as an intermediate layer, a method for manufacturing the optical device may include the steps of preparing a laminate including a first outer substrate, a first adhesive layer, a liquid crystal cell, a second adhesive layer, and a second outer substrate, in that order, and including an outer layer surrounding the sides of the liquid crystal cell, and autoclaving the laminate.

[0101] In another example, when the optical device includes a first polarizer and a second polarizer as intermediate layers, the method may include the steps of preparing a laminate including an outer layer that includes, in order, a first outer substrate, a first adhesive layer, the first polarizer, a second adhesive layer, a liquid crystal cell, a third adhesive layer, the second polarizer, a fourth adhesive layer, and a second outer substrate, and that surrounds the sides of the liquid crystal cell, and autoclaving the laminate.

[0102] Unless otherwise specified, the same description of the optical device can be applied to the method of manufacturing the optical device.

[0103] 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.

[0104] The autoclave step may be performed by applying heat and / or pressure to the laminate formed after the laminating step.

[0105] 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.

[0106] 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]

[0107] The liquid crystal cell and optical device of the present application properly maintain the cell gap of the liquid crystal cell, have excellent adhesion between the upper and lower substrates, and can solve the problems of pressing and liquid crystal overflow that may occur during the outer substrate bonding process due to delamination that may occur during post-electrode processing. [Brief explanation of the drawings]

[0108] [Figure 1] 1 shows an exemplary liquid crystal cell of the present application.

[0109] [Figure 2] 1 shows an exemplary liquid crystal cell of the present application.

[0110] [Figure 3] 1 shows an exemplary liquid crystal cell of the present application.

[0111] [Figure 4] 1 shows an exemplary liquid crystal cell of the present application.

[0112] [Figure 5] 1 shows images of the observed pressing and overflow defects due to delamination and after bonding in Example 1.

[0113] [Figure 6]10 is an image showing the observation of the pressing and overflow defects caused by delamination in Comparative Example 3. DETAILED DESCRIPTION OF THE INVENTION

[0114] 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.

[0115] Example 1

[0116] A polycarbonate film (Keiwa Co., Ltd.) with a thickness of approximately 100 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 Co., Ltd.) was bar-coated onto the first electrode layer and then 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.

[0117] A polycarbonate film (Keiwa) with a thickness of approximately 100 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 a 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.

[0118] A liquid crystal composition was coated on the vertical alignment film of the lower substrate to form a liquid crystal layer with a width (vertical length) of 560 mm. The widths of both ends of the lower substrate where the liquid crystal composition was not coated were 20 mm each. Next, a liquid crystal cell was fabricated by laminating the adhesive layer of the upper substrate so that it faced the liquid crystal layer. The upper and lower substrates were alternately stacked, resulting in a liquid crystal region with a width of 560 mm in the center between the upper and lower substrates. The widths of the non-liquid crystal regions on both sides of the liquid crystal region between the upper and lower substrates were 10 mm each. The widths of the regions where only the upper substrate and only the lower substrate were exposed at both ends of the liquid crystal cell were each 10 mm. Fabric carbon electrode tapes with widths of approximately 4 mm to 6 mm were attached to the regions where the upper substrate and the lower substrate were exposed at both ends of the liquid crystal cell.

[0119] The non-liquid crystal regions extended in the longitudinal direction of the lower substrate (second base layer), were located on both sides of the liquid crystal region, and the non-liquid crystal regions on both sides were parallel to each other. 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 (reverse twisted nematic) mode liquid crystal cell with an initial vertical alignment state.

[0120] Example 2.

[0121] The upper and lower substrates were fabricated in the same manner as in Example 1. A liquid crystal composition was coated on the vertical alignment film of the lower substrate to form a liquid crystal layer with a width (vertical length) of 570 mm. The widths of both ends of the lower substrate where the liquid crystal composition was not coated were 15 mm. A liquid crystal cell was then fabricated by laminating the upper substrate so that the adhesive layer faced the liquid crystal layer. The upper and lower substrates were alternately stacked, resulting in a liquid crystal region with a width of 570 mm in the center between the upper and lower substrates. The widths of the non-liquid crystal regions on both sides of the liquid crystal region between the upper and lower substrates were 5 mm each. The widths of the regions where only the upper and lower substrates were exposed at both ends of the liquid crystal cell were 10 mm each. Except for the above, the liquid crystal cell was fabricated in the same manner as in Example 1. The non-liquid crystal regions extended in the longitudinal direction of the lower substrate (second base layer), were located on both sides of the liquid crystal region, and the non-liquid crystal regions on both sides were parallel to each other. The liquid crystal composition contained a liquid crystal compound (JNC, SHN-5011XX) and a chiral dopant (HCCH, S811), and the pitch p of the liquid crystal layer was about 20 μm. The liquid crystal cell was an RTN mode liquid crystal cell in an initial vertical alignment state.

[0122] Example 3

[0123] The upper and lower substrates were fabricated in the same manner as in Example 1. Next, a liquid crystal composition was coated on the vertical alignment film of the lower substrate to form a liquid crystal layer with a width (vertical length) of 580 mm. The width of one side of the lower substrate where the liquid crystal composition was not coated was 20 mm. Next, a liquid crystal cell was fabricated by laminating the adhesive layer of the upper substrate facing the liquid crystal layer. The upper and lower substrates were alternately stacked, resulting in a liquid crystal region between the upper and lower substrates with a width of 580 mm. The non-liquid crystal region on one side of the liquid crystal region between the upper and lower substrates with a width of 10 mm. The widths of the regions where only the upper substrate was exposed and the regions where only the lower substrate was exposed at both ends of the liquid crystal cell were each 10 mm. The non-liquid crystal region extended in the longitudinal direction of the lower substrate and was located on one side of the liquid crystal region. The liquid crystal composition included a liquid crystal compound (JNC, SHN-5011XX) and a chiral dopant (HCCH, S811), and the liquid crystal layer pitch p was approximately 20 μm. The liquid crystal cell is an RTN mode liquid crystal cell in an initial vertical alignment state.

[0124] Example 4

[0125] The upper and lower substrates were fabricated in the same manner as in Example 1. A liquid crystal composition was coated on the vertical alignment film of the lower substrate to form a liquid crystal layer with a width (vertical length) of 180 mm. The widths of both ends of the lower substrate where the liquid crystal composition was not coated were 210 mm. Next, a liquid crystal cell was fabricated by laminating the upper substrate so that the adhesive layer faced the liquid crystal layer. The upper and lower substrates were alternately stacked, so that the width of the liquid crystal region in the center between the upper and lower substrates was 180 mm, the width of the non-liquid crystal regions on both sides of the liquid crystal region between the upper and lower substrates was 200 mm, and the widths of the regions where only the upper substrate and only the lower substrate were exposed at both ends of the liquid crystal cell were 10 mm, respectively. Except for the above, the liquid crystal cell was fabricated in the same manner as in Example 1. The non-liquid crystal regions extended in the longitudinal direction of the lower substrate (second base layer), were located on both sides of the liquid crystal region, and the non-liquid crystal regions on both sides were parallel to each other. The liquid crystal composition contained a liquid crystal compound (JNC, SHN-5011XX) and a chiral dopant (HCCH, S811), and the pitch p of the liquid crystal layer was about 20 μm. The liquid crystal cell was an RTN mode liquid crystal cell in an initial vertical alignment state.

[0126] Comparative Example 1

[0127] The upper and lower substrates were fabricated in the same manner as in Example 1. Next, a liquid crystal composition was coated on the vertical alignment film of the lower substrate to form a liquid crystal layer with a width (vertical length) of 576 mm. The widths of both ends of the lower substrate where the liquid crystal composition was not coated were 12 mm each. Next, a liquid crystal cell was fabricated by laminating the upper substrate so that the adhesive layer faced the liquid crystal layer. The upper and lower substrates were alternately laminated, resulting in a liquid crystal region with a width of 576 mm in the center between the upper and lower substrates. The widths of the non-liquid crystal regions on both sides of the liquid crystal region between the upper and lower substrates were each 2 mm. The widths of the regions where only the upper substrate was exposed and the regions where only the lower substrate was exposed at both ends of the liquid crystal cell were each 10 mm. The non-liquid crystal regions extended in the longitudinal direction of the lower substrate, were located on both sides of the liquid crystal region, and were parallel to each other. The liquid crystal composition contained a liquid crystal compound (JNC, SHN-5011XX) and a chiral dopant (HCCH, S811), and the pitch p of the liquid crystal layer was about 20 μm. The liquid crystal cell was an RTN mode liquid crystal cell in an initial vertical alignment state.

[0128] Comparative Example 2

[0129] The upper and lower substrates were fabricated in the same manner as in Example 1. Next, a liquid crystal composition was coated on the vertical alignment film of the lower substrate to form a liquid crystal layer with a width (vertical length) of 580 mm. The widths of both sides of the lower substrate where the liquid crystal composition was not coated were 10 mm each. Next, a liquid crystal cell was fabricated by laminating the upper substrate so that the adhesive layer faced the liquid crystal layer. At this time, the upper and lower substrates were alternately laminated, so that the width of the liquid crystal region in the center between the upper and lower substrates was 580 mm. No non-liquid crystal region was formed between the upper and lower substrates, and the widths of the region where only the upper substrate was exposed and the region where only the lower substrate was exposed were each 10 mm. Except for the above, the liquid crystal cell was fabricated in the same manner as in Example 1.

[0130] Example 5.

[0131] 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 polarizer, a second adhesive layer, the liquid crystal cell of Example 1, a third adhesive layer, a second polarizer, a fourth adhesive layer, and a second outer substrate. The first substrate layer of the liquid crystal cell was positioned closer to the first outer substrate, and the second substrate 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.

[0132] The first and second polarizers were PVA-based polarizers, and the light transmission axis of the first polarizer and the light transmission axis of the second polarizer were aligned at approximately 90 degrees. 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 outer layer was also made of a TPU layer (Argotec) with a thickness of 380 μm. The storage modulus of the TPU layer (Argotec) at 25°C and 1 Hz was 3,357,730 Pa, and the loss modulus at 25°C and 1 Hz was 1,485,510 Pa. The laminate was autoclaved at approximately 110°C and a pressure of approximately 2 atmospheres to fabricate an optical device.

[0133] Example 6

[0134] An optical device was fabricated in the same manner as in Example 5, except that the liquid crystal cell fabricated in Example 2 was used instead of the liquid crystal cell fabricated in Example 1.

[0135] Example 7

[0136] An optical device was fabricated in the same manner as in Example 5, except that the liquid crystal cell fabricated in Example 3 was used instead of the liquid crystal cell fabricated in Example 1.

[0137] Example 8

[0138] An optical device was fabricated in the same manner as in Example 5, except that the liquid crystal cell fabricated in Example 4 was used instead of the liquid crystal cell fabricated in Example 1.

[0139] Comparative Example 3.

[0140] An optical device was fabricated in the same manner as in Example 5, except that the liquid crystal cell fabricated in Comparative Example 1 was used instead of the liquid crystal cell fabricated in Example 1.

[0141] Comparative Example 4.

[0142] An optical device was fabricated in the same manner as in Example 5, except that the liquid crystal cell fabricated in Comparative Example 2 was used instead of the liquid crystal cell fabricated in Example 1.

[0143] Evaluation example 1. Evaluation of defects caused by delamination and overflow

[0144] The optical devices of Examples 5 to 8 and Comparative Examples 3 and 4 were evaluated for post-bonding compression and overflow defects due to delamination. Specifically, voltage was applied in a cross-polarization (cross pol) state before bonding the liquid crystal cell to the outer substrate, and non-uniform transmittance was observed in the corresponding areas. Figure 5 shows images of the compression and overflow defects observed in the optical device of Example 1, and Figure 6 shows images of the compression and overflow defects observed in the optical device of Comparative Example 3. In Figure 6, a indicates the outer substrate and adhesive layer area, b indicates the first polarizer, first base layer, electrode tape, and second polarizer area, c indicates the non-liquid crystal area, and d indicates the first polarizer, first base layer, liquid crystal layer, second base layer, and second polarizer area. As shown in Figure 6, liquid crystal flow occurred due to delamination in Comparative Example 3, and non-uniform transmittance was observed in certain areas, including dark areas where the cell gap could not be maintained due to a lack of liquid crystal, and bright areas where the cell gap was large. Comparative Example 4 also showed similar results to Comparative Example 3. On the other hand, in Example 5, the above-mentioned defects were not observed, as shown in Figure 5. Examples 6 to 8 also showed similar results to Example 5.

[0145] [Table 1] [Explanation of symbols]

[0146] 100:LCD area 200a, 200b, 200: Non-liquid crystal area 300a, 300b, 300: Regions where only one of the upper and lower substrates exists 400a, 400b, 400: Conductive tape 10a: First base layer 10b: First electrode layer 10c:Adhesive layer 30: Liquid crystal compound 20a: Second base layer 20b: Second electrode layer 20c:Spacer 20d: Alignment film

Claims

1. an upper substrate including a first substrate layer and an adhesive layer, and a lower substrate including a second substrate layer and a spacer; a region between the upper substrate and the lower substrate is divided into a liquid crystal region containing a liquid crystal compound and a non-liquid crystal region that does not contain the liquid crystal compound and is filled with air; The width (W1) of the non-liquid crystal region is 4 mm or more.

2. 2. The liquid crystal cell according to claim 1, wherein the non-liquid crystal regions have a line shape extending in a first direction, and the first direction is a longitudinal direction of the first substrate layer or the second substrate layer.

3. The surface of the first substrate layer and the surface of the second substrate layer each have a polygonal shape, 2. The liquid crystal cell of claim 1, wherein the non-liquid crystal region is located on a first side and a second side of the liquid crystal region, and the non-liquid crystal region located on the first side of the liquid crystal region and the non-liquid crystal region located on the second side of the liquid crystal region are not in contact with each other.

4. 4. The liquid crystal cell according to claim 3, wherein the non-liquid crystal region located on the first side of the liquid crystal region and the non-liquid crystal region located on the second side of the liquid crystal region are parallel to each other.

5. The liquid crystal cell according to claim 1 , wherein the non-liquid crystal region is located on only one of the sides of the liquid crystal region.

6. 2. The liquid crystal cell of claim 1, wherein there is an area on a side of the non-liquid crystal region where only one of the upper substrate and the lower substrate is present, and a conductive tape extending in a first direction is formed on one of the substrates.

7. 2. The liquid crystal cell according to claim 1, wherein the liquid crystal compound in the liquid crystal region switches its alignment state by application of a voltage.

8. The liquid crystal cell of claim 1 , wherein the upper substrate further comprises a first electrode layer between the first base layer and the adhesive layer, and the lower substrate further comprises a second electrode layer between the second base layer and the spacer.

9. The liquid crystal cell of claim 8 , wherein the upper substrate does not include an alignment film, and the lower substrate further includes an alignment film.

10. 10. An optical device comprising, in sequence, a first outer substrate, a liquid crystal cell according to claim 1 and a second outer substrate.

11. The optical device of claim 10 , wherein the first outer substrate and the second outer substrate are glass substrates.

12. The optical device of claim 10 , further comprising a first adhesive layer between the first outer substrate and the liquid crystal cell, and a second adhesive layer between the second outer substrate and the liquid crystal cell.

13. 13. The optical device of claim 12, wherein the first adhesive layer and the second adhesive layer are each 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.

14. 11. A motor vehicle comprising: a vehicle body having one or more openings formed therein; and an optical device according to claim 10 mounted in said openings.

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