Optical device

Abstract

The invention relates to an optical device. The optical device of the present application can appropriately maintain a cell gap of a liquid crystal cell, has excellent adhesiveness between an upper substrate and a lower substrate, and solves light leakage caused by irregular arrangement of liquid crystals occurring at the time of external impact.

Description

Technical Field

[0001] The present application relates to optical devices.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0070893, dated June 10, 2022, the disclosure of which is incorporated herein by reference in its entirety. Background Art

[0003] For 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 an upper substrate and a lower substrate and to impart adhesion between the upper substrate and the lower substrate.

[0004] In non-patent document 1 ("Tight Bonding of Two Plastic Substrates for Flexible LCDs" SID Symposium Digest, 38, pp. 653 to 656 (2007)), a technique for forming an organic film pattern in the form of a column or wall having a cell gap height on one substrate and fixing it to an opposite substrate using an adhesive is disclosed. However, in such a technique, the adhesive must be located only on the column surface or the wall surface, but the technique of micro-stamping the adhesive on the column surface or the wall surface has high process difficulty; it is difficult to control the adhesive thickness and area; there is a high probability that the adhesive will be pushed out when laminating the upper substrate with the lower substrate; and there is a risk that the adhesive may be contaminated into the alignment film or the liquid crystal. Summary of the invention

[0005] Technical issues

[0006] In order to maintain the cell gap of the liquid crystal cell and ensure the adhesion between the upper substrate and the lower substrate, it can be considered to form a spacer and an alignment film on the lower substrate, and to form a pressure-sensitive adhesive layer having both liquid crystal alignment force and adhesion force on the upper substrate, followed by lamination. However, assuming that the liquid crystal cell is mounted on a moving vehicle, when the vehicle passes over a speed bump or a severely uneven road surface, there is a problem of light leakage due to temporary irregular arrangement of liquid crystals occurring during external impact.

[0007] An object of the present application is to provide an optical device that can appropriately maintain a cell gap of a liquid crystal cell, has excellent adhesion between an upper substrate and a lower substrate, and solves light leakage caused by irregular arrangement of liquid crystals occurring upon external impact.

[0008] Technical Solution

[0009] Among the physical properties mentioned in this specification, when the measurement temperature affects the result, unless otherwise stated, the relevant physical properties are physical properties measured at room temperature. The term room temperature is a natural temperature without heating or cooling, which is generally a temperature in the range of about 10°C to 30°C, or about 23°C or about 25°C. In addition, unless otherwise stated in this specification, the unit of temperature is °C. Among the physical properties mentioned in this specification, when the measurement pressure affects the result, unless otherwise stated, the relevant physical properties are physical properties measured under normal pressure. The term normal pressure is a natural pressure without pressurization or decompression, wherein generally about 1 atmosphere is referred to as normal pressure.

[0010] The present application relates to an optical device. The optical device of the present application may sequentially include a first outer substrate, a liquid crystal cell, and a second outer substrate. The liquid crystal cell may include an upper substrate, a lower substrate, and a liquid crystal layer containing a liquid crystal compound between the upper substrate and the lower substrate. The upper substrate may include a first base layer and a pressure-sensitive adhesive layer. The lower substrate may include a second base layer and a spacer. The first base layer may be arranged closer to the first outer substrate than the second base layer, and the second base layer may be arranged closer to the second outer substrate than the first base layer.

[0011] The optical device of the present application may include a first buffer layer positioned between the first base layer and the first outer substrate. The liquid crystal cell may have a structure in which an oriented pressure-sensitive adhesive layer and a spacer are adjacent to each other. In the case of such a structure, due to the low elastic modulus of the pressure-sensitive adhesive layer, it is easily affected by external pressure, thereby deforming due to instantaneous pressure, and the orientation of the vertically arranged liquid crystals is distorted due to the related deformation, thereby light leakage may occur. According to the present application, since a buffer layer is introduced between the outer substrate and the liquid crystal cell, external impacts can be absorbed and defects of light leakage can be suppressed. In particular, by applying a buffer layer with a loss elastic modulus lower than the loss elastic modulus of the pressure-sensitive adhesive layer inside the liquid crystal cell as a buffer layer, the defect of light leakage can be effectively suppressed.

[0012] In one example, the loss elastic modulus of the pressure-sensitive adhesive layer at a temperature of 25°C and a frequency of 1 Hz may be in the range of 50,000 Pa to 2 MPa. The loss elastic modulus may be specifically 100,000 Pa or more, 300,000 Pa or more, 500,000 Pa or more, 700,000 Pa or more, or 900,000 Pa or more, and may be 1.8 MPa or less, 1.6 MPa or less, 1.4 MPa or less, 1.2 MPa or less, or 1.0 MPa or less. In one example, the storage elastic modulus of the pressure-sensitive adhesive layer at a temperature of 25°C and a frequency of 1 Hz may be in the range of 0.2 MPa to 10 MPa. The storage elastic modulus of the pressure-sensitive adhesive layer can be specifically 0.3MPa or more, 0.4MPa or more, 0.5MPa or more, 0.6MPa or more, or 0.7MPa or more, and can be 8MPa or less, 6MPa or less, 4MPa or less, 2MPa or less, or 1MPa or less. In the range of 0.6 radians / second to 100 radians / second, the values ​​of the storage elastic modulus and the loss elastic modulus of the pressure-sensitive adhesive layer can increase with the increase of frequency. For example, the storage elastic modulus and the loss elastic modulus of the pressure-sensitive adhesive layer at a temperature of 25°C and a frequency of 10Hz can be respectively higher than the storage elastic modulus and the loss elastic modulus at a temperature of 25°C and a frequency of 1Hz. The loss elastic modulus and the storage elastic modulus of the pressure-sensitive adhesive layer at a temperature of 25°C and a frequency of 10Hz can each independently be in the range of 1MPa to 10MPa. The loss elastic modulus and storage elastic modulus of pressure-sensitive adhesive layer can be 1.5MPa or more independently, and can be 10MPa or less, 8MPa or less, 6MPa or less, 4MPa or less or 2MPa or less. If the loss elastic modulus and / or storage elastic modulus of the pressure-sensitive adhesive layer inside the liquid crystal cell are too low, it may be difficult to maintain the cell gap of the liquid crystal cell, and if the loss elastic modulus and / or storage elastic modulus of the pressure-sensitive adhesive layer inside the liquid crystal cell are too high, it may be difficult to give pressure-sensitive adhesive effect, so loss elastic modulus and / or storage elastic modulus can be advantageous in the above range. In an example, under the same frequency conditions, the storage elastic modulus of the pressure-sensitive adhesive layer can have a value higher than the loss elastic modulus.

[0013] In one example, the loss elastic modulus of the first buffer layer at a temperature of 25° C. and a frequency of 1 Hz may be in the range of 1,000 Pa to 500,000 Pa. The loss elastic modulus may be specifically 3,000 Pa or more, 5,000 Pa or more, 7,000 Pa or more, 9,000 Pa or more, 10,000 Pa or more, 15,000 Pa or more, 20,000 Pa or more, 30,000 Pa or more, 40,000 Pa or more, or 50,000 Pa or more, and may be 400,000 Pa or less, 300,000 Pa or less, 200,000 Pa or less, 100,000 Pa or less, 80,000 Pa or less, 60,000 Pa or less, 40,000 Pa or less, 20,000 Pa or less, or 10,000 Pa or less. In one example, the storage elastic modulus of the first buffer layer at a temperature of 25° C. and a frequency of 1 Hz may be in the range of 100 Pa to 500,000 Pa. The storage elastic modulus of the first buffer layer may be specifically 1,000 Pa or more, 10,000 Pa or more, 30,000 Pa or more, 50,000 Pa or more, 70,000 Pa or more, 90,000 Pa or more, or 11,000 Pa or more, and may be 400,000 Pa or less, 300,000 Pa or less, 200,000 Pa or less, 150,000 Pa or less, 100,000 Pa or less, 80,000 Pa or less, 60,000 Pa or less, or 50,000 Pa or less. In the range of 0.6 radians / second to 100 radians / second, the values ​​of the loss elastic modulus and the storage elastic modulus of the first buffer layer may increase with increasing frequency. For example, the loss elastic modulus and the storage elastic modulus of the first buffer layer at a temperature of 25°C and a frequency of 10 Hz may be higher than the loss elastic modulus and the storage elastic modulus at a temperature of 25°C and a frequency of 1 Hz, respectively. The loss elastic modulus and the storage elastic modulus of the first buffer layer at a temperature of 25°C and a frequency of 10 Hz may each independently be in the range of 10,000 Pa to 500,000 MPa. The loss elastic modulus of the first buffer layer at a frequency of 10 Hz may be 15,000 Pa or more, and may be 400,000 Pa or less, 300,000 Pa or less, 200,000 Pa or less, 100,000 Pa or less, 80,000 Pa or less, 60,000 Pa or less, 40,000 Pa or less, or 20,000 Pa or less.The storage elastic modulus of the first buffer layer at a frequency of 10 Hz may be specifically 30,000 Pa or more, or 50,000 Pa or more, and may be 400,000 Pa or less, 300,000 Pa or less, 200,000 Pa or less, 150,000 Pa or less, 100,000 Pa or less, 80,000 Pa or less, or 70,000 Pa or less. If the loss elastic modulus and / or storage elastic modulus of the first buffer layer are too low, it may be difficult to manufacture it to a suitable thickness, and problems such as viscosity loss may occur in post-processing, and if the loss elastic modulus and / or storage elastic modulus of the first buffer layer are too high, it may not be enough to absorb the external impact applied to the liquid crystal unit, so the loss elastic modulus and / or storage elastic modulus of the first buffer layer may be suitable within the above range. In one example, under the condition of the same wave number, the storage elastic modulus of the first buffer layer may have a higher value than the loss elastic modulus.

[0014] The first outer substrate and the second outer substrate may be independently an inorganic substrate or a plastic substrate. A known inorganic substrate may be used as the inorganic substrate without any particular restriction. In one example, a glass substrate with excellent light transmittance may be used as the inorganic substrate. As examples of glass substrates, soda-lime glass substrates, general tempered glass substrates, borosilicate glass substrates, or alkali-free glass substrates may be used, but are not limited thereto. As the polymer substrate, a cellulose film such as TAC (triacetyl cellulose) or DAC (diacetyl cellulose) can be used; a COP (cyclic olefin copolymer) film such as a norbornene derivative; an acrylic film such as PAR (polyacrylate) or PMMA (poly(methyl methacrylate)); a PC (polycarbonate) film; a polyolefin film such as PE (polyethylene) or PP (polypropylene); a PVA (polyvinyl alcohol) film; a PI (polyimide) film; a sulfone-based film such as PSF (polysulfone) film, PPS (polyphenylsulfone) film or PES (polyethersulfone) film; a PEEK (polyetheretherketone) film; a PEI (polyetherimide) film; a polyester-based film such as PEN (polyethylene naphthalate) film or PET (polyethylene terephthalate) film; or a fluororesin film, etc., but not limited thereto. In each of the first outer substrate and the second outer substrate, as required, a coating of gold, silver, or a silicon compound (such as silicon dioxide or silicon monoxide) or a functional layer such as an antireflection layer may also be present.

[0015] In one example, the first outer substrate and / or the second outer substrate may be a glass substrate.

[0016] The thickness of the first outer substrate and the second outer substrate can be about 0.3 mm or more respectively. In another example, the thickness can be about 0.5 mm or more, 1 mm or more, 1.5 mm or more, or about 2 mm or more, and can also 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.

[0017] The first outer substrate and the second outer substrate can be a flat substrate, or can be a substrate with a curved surface shape. For example, the first outer substrate and the second outer substrate can be a flat substrate at the same time, have a curved surface shape at the same time, or either one can be a flat substrate and the other can be a substrate with a curved surface shape. In addition, at this, when having a curved surface shape at the same time, each curvature or radius of curvature can be the same or different. In this specification, curvature or radius of curvature can be measured in a manner known in the industry, and for example, non-contact equipment such as 2D profile laser sensor, color confocal line sensor or 3D measurement confocal microscope can be used to measure. The method of measuring curvature or radius of curvature using such equipment is known.

[0018] With respect to the first outer substrate and the second outer substrate, for example, when the curvature or the radius of curvature on the front surface and the back surface are different, the respective curvatures or the radius of curvature of the opposite surfaces, that is, the curvature or the radius of curvature of the surface facing the second outer substrate in the case of the first outer substrate and the curvature or the radius of curvature of the surface facing the first outer substrate in the case of the second outer substrate, can be a reference. In addition, when the relevant surface has a portion where the curvature or the radius of curvature is not constant and different, the maximum curvature or the radius of curvature can be a reference, or the minimum curvature or the radius of curvature can be a reference, or the average curvature or the average radius of curvature can be a reference.

[0019] The difference in curvature or radius of curvature of the first outer substrate and the second outer substrate can be within about 10%, within 9%, within 8%, within 7%, within 6%, within 5%, within 4%, within 3%, within 2%, or within about 1%. When the large curvature or radius of curvature is CL and the small curvature or radius of curvature is CS, the difference in curvature or radius of curvature is a value calculated by 100×(CL-CS) / CS. In addition, the lower limit of the difference in curvature or radius of curvature is not particularly limited. Since the difference in curvature or radius of curvature of the first outer substrate and the second outer substrate can be the same, the difference in curvature or radius of curvature can be about 0% or greater, or greater than about 0%. Such control of curvature or radius of curvature is useful in a structure in which a liquid crystal unit and an adhesive layer contact each other as in the optical device of the present application. That is, when the curvature or the radius of curvature exceeds 10%, when the outer substrate and the liquid crystal cell are in contact with the adhesive layer to be described below, the problem of the bonded outer substrate being scattered due to the deterioration of the adhesive force may occur. However, if it is controlled within 10%, the problem of the bonded outer substrate being scattered due to the deterioration of the adhesive force can be effectively prevented.

[0020] The first outer substrate and the second outer substrate may have the same curvature sign. In other words, the first outer substrate and the second outer substrate may be bent in the same direction. That is, in the above case, the center of curvature of the first outer substrate and the center of curvature of the second outer substrate are both present in the same part of the upper and lower parts of the first outer substrate and the second outer substrate. When the first outer substrate and the second outer substrate are bent in the same direction, the first outer substrate and the second outer substrate can be more effectively bonded by the adhesive layer, and after bonding, the first outer substrate and the second outer substrate can be more effectively prevented from deteriorating the bonding force with the liquid crystal cell and / or the polarizer.

[0021] The specific range of each curvature or radius of curvature of the first outer substrate and the second outer substrate is not particularly limited. In one example, the radius of curvature of each of the first outer substrate and the second outer substrate may be about 100R or greater, 200R or greater, 300R or greater, 400R or greater, 500R or greater, 600R or greater, 700R or greater, 800R or greater, or about 900R or greater, or may be about 10,000R or less, 9,000R or less, 8,000R or less, 7,000R or less , 6,000R or less, 5,000R or less, 4,000R or less, 3,000R or less, 2,000R or less, 1,900R or less, 1,800R or less, 1,700R or less, 1,600R or less, 1,500R or less, 1,400R or less, 1,300R or less, 1,200R or less, 1,100R or less, or about 1,050R or less. Here, R means the curvature of a circle with a radius of 1mm. Therefore, here, for example, 100R is the curvature of a circle with a radius of 100mm or the radius of curvature of such a circle. The first outer substrate and the second outer substrate may have the same or different radii of curvature within the above range. In an example, when the curvatures of the first outer substrate and the second outer substrate are different from each other, the radius of curvature of the substrate with a large curvature may be within the above range. In one example, when the curvatures of the first outer substrate and the second outer substrate are different from each other, the substrate having a larger curvature may be a substrate disposed in the direction of gravity when the optical device is used. When the curvature or the radius of curvature of the first substrate and the second substrate is controlled as above, even if the adhesive force of the adhesive layer to be described below is reduced, the net force as the sum of the restoring force and gravity can also play a role in preventing widening.

[0022] 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.

[0023] In one example, the optical device may further include a first adhesive layer in contact with the inner surface of the first outer substrate, and a second adhesive layer in contact with the inner surface of the second outer substrate. In the present specification, the inner surface of the first outer substrate may mean the surface of the first outer substrate facing the liquid crystal unit, and the inner surface of the second outer substrate may mean the surface of the second outer substrate facing the liquid crystal unit. In the present specification, the situation where A contacts B may mean a state where A and B are in direct contact without any intermediate between A and B. The surface of the first adhesive layer that is not in contact with the first outer substrate may be in contact with the first polarizer or the first buffer layer described below. The surface of the second adhesive layer that is not in contact with the second outer substrate may be in contact with the second polarizer or the second buffer layer described below.

[0024] In one example, the loss elastic modulus of the first adhesive layer and the second adhesive layer may each be higher than the loss elastic modulus of the pressure-sensitive adhesive layer inside the liquid crystal cell. In addition, the storage elastic modulus of the first adhesive layer and the second adhesive layer may each be higher than the storage elastic modulus of the pressure-sensitive adhesive layer. When the storage elastic modulus or loss elastic modulus of the first adhesive layer and the second adhesive layer is too low, the thermal behavior of the film cannot be controlled during the endurance process, so that appearance defects may occur. In one example, the loss elastic modulus of the first adhesive layer and the second adhesive layer at a temperature of 25°C and a frequency of 1Hz may each be in the range of 1MPa to 100MPa. The loss elastic modulus may be specifically 80MPa or less, 60MPa or less, 40MPa or less, 20MPa or less, 10MPa or less, 8MPa or less, 6MPa or less, 4MPa or less, or 2MPa or less. In one example, the storage elastic modulus of the first adhesive layer and the second adhesive layer at a temperature of 25°C and a frequency of 1Hz may each be in the range of 1MPa to 100MPa. The storage elastic modulus may be specifically 2MPa or greater, or 3MPa or greater, and may be 80MPa or less, 60MPa or less, 40MPa or less, 20MPa or less, 10MPa or less, 8MPa or less, 6MPa or less, or 4MPa or less. In the range of 0.6 radians / second to 100 radians / second, the values ​​of the storage elastic modulus and the loss elastic modulus of the adhesive layer may increase with increasing frequency. For example, the storage elastic modulus and the loss elastic modulus of the first adhesive layer and the second adhesive layer at a temperature of 25°C and a frequency of 10Hz may be higher than the storage elastic modulus and the loss elastic modulus at a temperature of 25°C and a frequency of 1Hz, respectively. The loss elastic modulus and the storage elastic modulus of the first adhesive layer and the second adhesive layer at a temperature of 25°C and a frequency of 10Hz may each independently be in the range of 1MPa to 100MPa. The storage elastic modulus of the first adhesive layer and the second adhesive layer can be 2MPa or more, 4MPa or more, or 6MPa or more, and can be 80MPa or less, 60MPa or less, 40MPa or less, 20MPa or less, or 10MPa or less, or 8MPa or less. The loss elastic modulus of the first adhesive layer and the second adhesive layer can be 2MPa or more, or 3MPa or more, and can be 80MPa or less, 60MPa or less, 40MPa or less, 20MPa or less, 10MPa or less, 8MPa, 6MPa or less, or 4MPa or less. In an example, under the same frequency conditions, the storage elastic modulus of the first adhesive layer and the second adhesive layer can each have a higher value than the loss elastic modulus of the first adhesive layer and the second adhesive layer.

[0025] In one example, the first buffer layer may contact an outer side surface of the first base layer.In the present specification, the outer side surface of the first base layer may mean a surface of the first base layer facing the first outer substrate.

[0026] In another example, the first buffer layer may contact the inner side surface of the first adhesive layer. In the present specification, the inner side surface of the first adhesive layer may mean a surface of the first adhesive layer facing the liquid crystal cell.

[0027] In one example, the optical device may further include a third adhesive layer in contact with the outer surface of the first base layer, and a fourth adhesive layer in contact with the outer surface of the second base layer. In this specification, the outer surface of the second base layer may refer to the surface of the second base layer facing the second outer substrate. The surface of the third adhesive layer that is not in contact with the first base layer may be in contact with the first polarizer to be described below. The surface of the fourth adhesive layer that is not in contact with the second base layer may be in contact with the second polarizer to be described below.

[0028] The third adhesive layer may be positioned between the first polarizer and the liquid crystal cell, and the fourth adhesive layer may be positioned between the second polarizer and the liquid crystal cell. In this case, the thickness of the third adhesive layer and / or the fourth adhesive layer may each be 380 μm or less. Thus, the separation distance between the first polarizer and the second polarizer is minimized, so that the structural safety of the liquid crystal cell can be ensured while reducing light leakage. The lower limit of the thickness of the third adhesive layer and / or the fourth adhesive layer may each be 10 μm or greater.

[0029] The loss elastic modulus of the third adhesive layer and the fourth adhesive layer can be higher than the loss elastic modulus of the pressure-sensitive adhesive layer. In addition, the storage elastic modulus of the third adhesive layer and the fourth adhesive layer can be higher than the storage elastic modulus of the pressure-sensitive adhesive layer. When the storage elastic modulus or the loss elastic modulus of the third adhesive layer and the fourth adhesive layer are too low, the thermal behavior of the film during the durable process cannot be controlled, thereby appearance defects may occur. In an example, the storage elastic modulus of the third adhesive layer and the fourth adhesive layer can be in the range of 1MPa to 100MPa respectively. In an example, the loss elastic modulus of the third adhesive layer and the fourth adhesive layer can be in the range of 1MPa to 100MPa respectively. About the details of the loss elastic modulus or the storage elastic modulus of the third adhesive layer and the fourth adhesive layer, the content described in the first adhesive layer and the second adhesive layer can be equally applied here.

[0030] The optical device may further 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. In this specification, the term polarizer means a film, sheet or element having a polarization function. A polarizer is a functional element capable of extracting light vibrating in one direction from incident light vibrating in multiple directions.

[0031] The first polarizer and the second polarizer may each be an absorptive polarizer or a reflective polarizer. In the present specification, an absorptive polarizer means an element that exhibits selective transmission and absorption characteristics for incident light. For example, a polarizer can transmit light vibrating in any direction of incident light vibrating in multiple directions and can absorb light vibrating in other directions. In the present specification, a reflective polarizer means an element that exhibits selective transmission and reflection characteristics for incident light. For example, a polarizer can transmit light vibrating in any direction of incident light vibrating in multiple directions and can reflect light vibrating in other directions. According to one example of the present application, the polarizer may be an absorptive polarizer.

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

[0033] In one example, the first polarizer and the second polarizer can each be a stretched polymer film dyed with iodine or an anisotropic dye. As a stretched polymer film, a PVA (poly (vinyl alcohol)) stretched film can be exemplified. In another example, the first polarizer and the second polarizer can each be a guest-host polarizer, wherein a liquid crystal polymerized in an oriented state is a host, and an anisotropic dye arranged according to the orientation of the liquid crystal is a guest. In another example, the first polarizer and the second polarizer can each be a thermotropic liquid crystal film or a lyotropic liquid crystal film.

[0034] A protective film, an anti-reflection film, a delay film, a pressure-sensitive adhesive layer, an adhesive layer, a surface treatment layer, etc. may be additionally formed on one side or both sides of the first polarizer and the second polarizer, respectively. The delay film may be, for example, a 1 / 4 wave plate or a 1 / 2 wave plate. The in-plane delay value of the 1 / 4 wave plate to the light with a wavelength of 550nm may be in the range of about 100nm to 180nm, which is 100nm or 150nm. The in-plane delay value of the 1 / 2 wave plate to the light with a wavelength of 550nm may be in the range of about 200nm to 300nm or 250nm to 300nm. The delay film may be, for example, a stretched polymer film or a liquid crystal polymer film.

[0035] The transmittance of the first polarizer and the second polarizer to light with a wavelength of 550nm can each be in the range of 40% to 50%. The transmittance can refer to the single transmittance of the polarizer to light with a wavelength of 550nm. The single transmittance of the polarizer can be measured using, for example, a spectrometer (V7100, manufactured by Jasco). For example, air is set as the baseline in a state where the polarizer sample (without the upper protective film and the lower protective film) is mounted on the device, and after measuring each transmittance in a state where the axis of the polarizer sample is vertically and horizontally aligned with the axis of the reference polarizer, the single transmittance can be calculated.

[0036] 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 formed by the light transmission axis of the first polarizer and the light transmission axis of the second polarizer may be in the range of 80 to 100 degrees or 85 to 95 degrees. 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 separation distance between the first polarizer and the second polarizer.

[0037] In one example, the optical device may further include a fifth adhesive layer in contact with the outer surface of the first polarizer, and a sixth adhesive layer in contact with the outer surface of the second polarizer. The outer surface of the first polarizer may refer to the surface of the first polarizer facing the first outer substrate. The outer surface of the second polarizer may refer to the surface of the second polarizer facing the second outer substrate. The surface of the fifth adhesive layer that is not in contact with the first polarizer may be in contact with the first buffer layer, and the surface of the sixth adhesive layer that is not in contact with the second polarizer may be in contact with the second buffer layer to be described below. The storage elastic modulus of the fifth adhesive layer and the sixth adhesive layer may each be higher than the storage elastic modulus of the pressure-sensitive adhesive layer. In addition, the loss elastic modulus of the fifth adhesive layer and the sixth adhesive layer may each be higher than the loss elastic modulus of the pressure-sensitive adhesive layer. If the storage elastic modulus or loss elastic modulus of the fifth adhesive layer and the sixth adhesive layer are too low, the thermal behavior of the film cannot be controlled during the endurance process, thereby appearance defects may occur. In one example, the storage elastic modulus of the fifth adhesive layer and the sixth adhesive layer may each be in the range of 1MPa to 100MPa. In one example, the loss elastic modulus of the fifth adhesive layer and the sixth adhesive layer may each be in the range of 1 MPa to 100 MPa. Regarding the details of the loss elastic modulus or storage elastic modulus of the fifth adhesive layer and the sixth adhesive layer, the contents described in the first adhesive layer and the second adhesive layer may be equally applied here.

[0038] In one example, the optical device may further include a second buffer layer. The second buffer layer may be positioned between the second base layer of the liquid crystal unit and the second outer substrate. The loss elastic modulus of the second buffer layer may be lower than the loss elastic modulus of the pressure-sensitive adhesive layer. The storage elastic modulus of the second buffer layer may be lower than the storage elastic modulus of the pressure-sensitive adhesive layer. When the optical device further includes a second buffer layer, light leakage may be more advantageously suppressed by absorbing external impacts. If no particular mention is made of the second buffer layer, the same configuration as the first buffer layer may be applied.

[0039] In one example, the second buffer layer may be in contact with the outer side surface of the second base layer. Alternatively, the second buffer layer may be in contact with the inner side surface of the second adhesive layer.

[0040] In one example, the optical device may include the first buffer layer, and may not include the second buffer layer. In another example, the optical device may include both the first buffer layer and the second buffer layer. In this case, when the optical device includes both the first buffer layer and the second buffer layer, it may be advantageous in suppressing light leakage.

[0041] The total thickness of the buffer layer included in the optical device may be, for example, in the range of 50 μm to 2000 μm. The total thickness of the buffer layer may be specifically 100 μm or more, 200 μm or more, 300 μm or more, 400 μm or more, 500 μm or more, 600 μm or more, 700 μm or more, 800 μm or more, 900 μm or more, or 1000 μm or more, and may be 1800 μm or less, 1600 μm or less, or 1400 μm or less. When the optical device includes a first buffer layer but does not include a second buffer layer, the total thickness of the buffer layer may mean the thickness of the first buffer layer, and when the optical device includes both the first buffer layer and the second buffer layer, it may mean the sum of the thickness of the first buffer layer and the thickness of the second buffer layer. The first buffer layer and / or the second buffer layer may each have a single-layer structure or a multi-layer structure. When the first buffer layer and / or the second buffer layer has a multilayer structure in which a plurality of sub-buffer layers are laminated, the thickness of the sub-buffer layer may be, for example, in the range of 100 μm to 500 μm, 200 μm to 400 μm, or 200 μm to 300 μm.

[0042] As the first buffer layer and the second buffer layer, a pressure-sensitive adhesive layer satisfying the storage elastic modulus or the loss elastic modulus may be used. The pressure-sensitive adhesive layer may be optically transparent. The average transmittance of the pressure-sensitive adhesive layer to the visible light region (e.g., a wavelength of 380 nm to 780 nm) may be about 80% or more, 85% or more, 90% or more, or 95% or more.

[0043] As the pressure-sensitive adhesive layer, various types of pressure-sensitive adhesives referred to in the industry as so-called OCA (optically clear adhesive) can be appropriately used. The pressure-sensitive adhesive is different from an OCR (optically clear resin) type adhesive that cures after the object to be attached is bonded in that it cures before the object to be attached is bonded. As the pressure-sensitive adhesive, for example, an acrylic pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, an epoxy-based pressure-sensitive adhesive, or a urethane-based pressure-sensitive adhesive can be applied.

[0044] In one example, the first buffer layer and / or the second buffer layer may have a storage elastic modulus of 500,000 Pa or less, 400,000 Pa or less, 300,000 Pa or less, 200,000 Pa or less, 150,000 Pa or less, 100,000 Pa or less, 80,000 Pa or less, or 60,000 Pa or less in the entire frequency band within the range of 0.6 rad / sec to 100 rad / sec at a temperature of 25°C. The storage elastic modulus of the first buffer layer and / or the second buffer layer may be 100 Pa or more, 1,000 Pa or more, 5000 Pa or more, 10,000 Pa or more, 20,000 Pa or more, 30,000 Pa or more, or 40,000 Pa or more in the entire frequency band within the range of 0.6 rad / sec to 100 rad / sec at a temperature of 25°C.

[0045] In one example, the first buffer layer and / or the second buffer layer may have a loss elastic modulus of 500,000 Pa or less, 400,000 Pa or less, 300,000 Pa or less, 200,000 Pa or less, 150,000 Pa or less, 100,000 Pa or less, 80,000 Pa or less, 60,000 Pa or less, 40,000 Pa or less, or 20,000 Pa or less in the entire frequency band within the range of 0.6 rad / sec to 100 rad / sec at a temperature of 25°C. The first buffer layer and / or the second buffer layer may have a loss elastic modulus of 1,000 Pa or more, 3,000 Pa or more, 5000 Pa or more, 7,000 Pa or more, or 9,000 Pa or more in the entire frequency band within the range of 0.6 rad / sec to 100 rad / sec at a temperature of 25°C.

[0046] In one example, the loss elastic modulus of the pressure-sensitive adhesive layer in the entire frequency band within the range of 0.6 rad / s to 100 rad / s at a temperature of 25°C may be 6,000,000 Pa or less, 5,000,000 Pa or less, 4,000,000 Pa or less, 3,000,000 Pa or less, or 2,500,000 Pa or less, and may be 1,000 Pa or more, 3,000 Pa or more, 5,000 Pa or more, 7,000 Pa or more, or 9,000 Pa or more. In one example, the storage elastic modulus of the pressure-sensitive adhesive layer in the entire frequency band within the range of 0.6 rad / s to 100 rad / s at a temperature of 25°C may be 6,000,000 Pa or less, 5,000,000 Pa or less, 4,000,000 Pa or less, 3,000,000 Pa or less, or 2,500,000 Pa or less, and may be 1,000 Pa or more, 3,000 Pa or more, 5,000 Pa or more, or 7,000 Pa or more.

[0047] In one example, the loss elastic modulus of the first to sixth adhesive layers in the entire frequency band within the range of 0.6 radian / second to 100 radian / second at a temperature of 25°C may be independently 100 MPa or less, 80 MPa or less, 60 MPa or less, 40 MPa or less, 20 MPa or less, or 10 MPa or less, and may be 0.1 MPa or more, 0.5 MPa or more, or 1.0 MPa or more. In one example, the storage elastic modulus of the first to sixth adhesive layers in the entire frequency band within the range of 0.6 radian / second to 100 radian / second at a temperature of 25°C may be independently 100 MPa or less, 80 MPa or less, 60 MPa or less, 40 MPa or less, 20 MPa or less, or 10 MPa or less, and may be 0.1 MPa or more, 0.5 MPa or more, or 1.0 MPa or more.

[0048] Figures 1 to 4 The structures of the optical devices of the first example to the fourth example of the present application are exemplarily shown respectively.

[0049] Figure 1 The structure of such an optical device is exemplarily shown: the optical device sequentially includes a first outer substrate 101, a first adhesive layer 401, a first polarizer 501, a first buffer layer 301, a liquid crystal unit 200, a second buffer layer 302, a second polarizer 502, a second adhesive layer 402 and a second outer substrate 102.

[0050] Figure 2The structure of such an optical device is exemplarily shown: the optical device sequentially includes a first outer substrate 101, a first adhesive layer 401, a first buffer layer 301, a first polarizer 501, a third adhesive layer 403, a liquid crystal unit 200, a fourth adhesive layer 404, a second polarizer 502, a second buffer layer 302, a second adhesive layer 402 and a second outer substrate 102.

[0051] Figure 3 The structure of such an optical device is exemplarily shown: the optical device sequentially includes a first outer substrate 101, a first adhesive layer 401, a first buffer layer 301, a fifth adhesive layer 405, a first polarizer 501, a third adhesive layer 403, a liquid crystal unit 200, a fourth adhesive layer 404, a second polarizer 502, a sixth adhesive layer 406, a second buffer layer 302, a second adhesive layer 402 and a second outer substrate 102.

[0052] Figure 4 The structure of such an optical device is exemplarily shown: the optical device sequentially includes a first outer substrate 101, a first adhesive layer 401, a first buffer layer 301, a first polarizer 501, a third adhesive layer 403, a liquid crystal unit 200, a fourth adhesive layer 404, a second polarizer 502, a second adhesive layer 402 and a second outer substrate 102.

[0053] Figure 5 The liquid crystal cell is shown as an example. Figure 5 As shown, the liquid crystal unit may include a first base layer 10a, a pressure-sensitive adhesive layer 10c formed on the inside of the first base layer, a second base layer 20a arranged opposite to the first base layer 10a, a spacer 20c formed on the inside of the second base layer 20a, and a liquid crystal layer 30 positioned between the first base layer 10a and the second base layer 10b.

[0054] As the first base layer and the second base layer, for example, an inorganic film such as a glass film, a crystalline or amorphous silicon film or a quartz or ITO (Indium Tin Oxide) film, or a polymer film or the like can be used, and in terms of realizing a flexible member, a polymer film can be used.

[0055] In one example, the first base layer and the second base layer can each be a polymer film. As the polymer film, TAC (triacetyl cellulose); COP (cyclic olefin copolymer) such as norbornene derivatives; PMMA (poly (methyl methacrylate)); PC (polycarbonate); PE (polyethylene); PP (polypropylene); PVA (polyvinyl alcohol); DAC (diacetyl cellulose); PAC (polyacrylate); PES (polyether sulfone); PEEK (polyether ether ketone); PPS (polyphenyl sulfone); PEI (polyetherimide); PEN (polyethylene naphthalate); PET (polyethylene terephthalate); PI (polyimide); PSF (polysulfone); PAR (polyarylate) or amorphous fluororesin, etc. can be used, but are not limited thereto. In the first base layer and the second base layer, as needed, a coating of gold, silver, or a silicon compound (such as silicon dioxide or silicon monoxide) or a functional layer such as an anti-reflection layer can also be present.

[0056] The thickness of the first base layer and the second base layer may each be about 10 μm to about 1,000 μm. As another example, the thickness of the base layers 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 may be 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 base layer and the second base layer satisfies the above range, appearance defects such as wrinkles can be reduced when an optical device is manufactured by laminating a liquid crystal unit with an outer substrate.

[0057] The pressure-sensitive adhesive layer may be present on the inner side surface of the first base layer.In the present specification, the "inner side surface" of the configuration included in the liquid crystal cell may mean a surface facing the liquid crystal layer.

[0058] The pressure-sensitive adhesive layer may be optically transparent. The average transmittance of the pressure-sensitive adhesive layer in the visible light region (eg, wavelength of 380 nm to 780 nm) may be about 80% or more, 85% or more, 90% or more, or 95% or more.

[0059] The pressure-sensitive adhesive layer can be a liquid crystal orientation pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer can be, for example, a vertical orientation pressure-sensitive adhesive layer or a horizontal orientation pressure-sensitive adhesive layer. In this specification, "vertical orientation pressure-sensitive adhesive" can mean a pressure-sensitive adhesive having an attachment force that can bond the upper substrate to the lower substrate while giving the adjacent liquid crystal compound a vertical orientation force. In this specification, "horizontally oriented pressure-sensitive adhesive" can mean a pressure-sensitive adhesive having an attachment force that can bond the upper substrate to the lower substrate while giving the adjacent liquid crystal compound a horizontal orientation force. The pretilt angle of the adjacent liquid crystal compound relative to the vertical orientation pressure-sensitive adhesive can be in the range of 80 to 90 degrees, 85 to 90 degrees, or about 87 to 90 degrees, and the pretilt angle of the adjacent liquid crystal compound relative to the horizontal orientation pressure-sensitive adhesive can be in the range of 0 to 10 degrees, 0 to 5 degrees, or 0 to 3 degrees.

[0060] In the present specification, the pretilt angle may mean an angle formed by the director of the liquid crystal compound relative to a plane horizontal to the liquid crystal alignment pressure-sensitive adhesive or alignment film in a state where no voltage is applied. In the present specification, the director of the liquid crystal compound may mean an optical axis or a slow axis of the liquid crystal layer. Alternatively, when the liquid crystal compound has a rod shape, the director of the liquid crystal compound may mean a long axis direction, and when the liquid crystal compound has a disc shape, the director of the liquid crystal compound may mean an axis parallel to the normal direction of the disc plane.

[0061] The thickness of the pressure-sensitive adhesive layer may be, for example, in the range of 3 μm to 15 μm. When the thickness of the pressure-sensitive adhesive layer is within the above range, it is possible to minimize defects (such as squeezing or aggregation of the pressure-sensitive adhesive) when used to manufacture a liquid crystal cell while ensuring the adhesion between the upper substrate and the lower substrate.

[0062] As the pressure-sensitive adhesive layer, various types of pressure-sensitive adhesives referred to in the industry as so-called OCA (optically clear adhesive) can be appropriately used. The pressure-sensitive adhesive is different from an OCR (optically clear resin) type adhesive that cures after the object to be attached is bonded in that it cures before the object to be attached is bonded. As the pressure-sensitive adhesive, for example, an acrylic pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, an epoxy-based pressure-sensitive adhesive, or a urethane-based pressure-sensitive adhesive can be applied.

[0063] The pressure-sensitive adhesive layer may include a cured product of a pressure-sensitive adhesive resin. In one example, the pressure-sensitive adhesive layer may include a silicone-based pressure-sensitive adhesive. The silicone-based pressure-sensitive adhesive may include a cured product of a curable silicone compound as the pressure-sensitive adhesive resin.

[0064] The type of the curable organic silicon compound is not particularly limited, and for example, a heat-curable organic silicon compound or an ultraviolet-curable organic silicon compound may be used. The curable organic silicon compound may be referred to as a pressure-sensitive adhesive resin.

[0065] In one example, the curable organosilicon compound may be an addition-curable organosilicon compound.

[0066] Specifically, the addition-curing organosilicon compound can be exemplified by (1) an organopolysiloxane containing two or more alkenyl groups in the molecule and (2) an organopolysiloxane containing two or more silicon-bonded hydrogen atoms in the molecule, but is not limited thereto. Such an organosilicon compound can form a cured product by an addition reaction, for example, in the presence of a catalyst such as platinum.

[0067] More specific examples of the (1) organopolysiloxane that can be used in the present application may include: a dimethylsiloxane-methylvinylsiloxane copolymer terminated with a trimethylsiloxane group at both ends of the molecular chain, a methylvinylpolysiloxane terminated with a trimethylsiloxane group at both ends of the molecular chain, a dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymer terminated with a trimethylsiloxane group at both ends of the molecular chain, a dimethylpolysiloxane terminated with a dimethylvinylsiloxane group at both ends of the molecular chain, a methylvinylpolysiloxane terminated with a dimethylvinylsiloxane group at both ends of the molecular chain, a dimethylsiloxane-methylvinylsiloxane copolymer terminated with a dimethylvinylsiloxane group at both ends of the molecular chain, a dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymer terminated with a dimethylvinylsiloxane group at both ends of the molecular chain, 1 2SiO 1 / 2 The siloxane units represented by R 1 2R 2 SiO 1 / 2 The siloxane units represented by SiO 4 / 2 The organopolysiloxane copolymer of siloxane units represented by 1 2R 2 SiO 1 / 2 The siloxane units represented by SiO 4 / 2 The organopolysiloxane copolymer of siloxane units represented by 1 R 2 SiO 2 / 2 The siloxane units represented by R 1 SiO 3 / 2 The siloxane unit represented by R 2 SiO 3 / 2 The organopolysiloxane copolymers of siloxane units represented by, and mixtures of two or more of the foregoing, but not limited thereto.1 is a hydrocarbon group other than an alkenyl group, specifically, an alkyl group such as methyl, ethyl, propyl, butyl, pentyl, hexyl or heptyl; an aryl group such as phenyl, tolyl, xylyl or naphthyl; an aralkyl group such as benzyl or phenethyl; an alkyl group substituted with a halogen such as chloromethyl, 3-chloropropyl or 3,3,3-trifluoropropyl; and the like. In addition, herein, R 2 is an alkenyl group, which may specifically be a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group or a heptenyl group or the like.

[0068] More specific examples of (2) organopolysiloxanes that can be used in the present application may include: methylhydrogenpolysiloxane terminated with trimethylsiloxane groups at both ends of the molecular chain, dimethylsiloxane-methylhydrogen copolymer terminated with trimethylsiloxane groups at both ends of the molecular chain, dimethylsiloxane-methylhydrogensiloxane-methylphenylsiloxane copolymer terminated with trimethylsiloxane groups at both ends of the molecular chain, dimethylpolysiloxane terminated with dimethylhydrogensiloxane groups at both ends of the molecular chain, dimethylsiloxane-methylphenylsiloxane copolymer terminated with dimethylhydrogensiloxane groups at both ends of the molecular chain, methylphenylpolysiloxane terminated with dimethylhydrogensiloxane groups at both ends of the molecular chain, 1 3SiO 1 / 2 The siloxane unit represented by R 1 2HSiO 1 / 2 The siloxane units represented by SiO 4 / 2 The organopolysiloxane copolymer of siloxane units represented by 1 2HSiO 1 / 2 The siloxane units represented by SiO 4 / 2 The organopolysiloxane copolymer of siloxane units represented by 1 HSiO 2 / 2 The siloxane units represented by R 1 SiO 3 / 2 Siloxane units represented by HSiO 3 / 2 The organopolysiloxane copolymers of siloxane units represented by, and mixtures of two or more of the foregoing, but not limited thereto. 1 is a hydrocarbon group other than an alkenyl group, which may specifically be an alkyl group such as methyl, ethyl, propyl, butyl, pentyl, hexyl or heptyl; an aryl group such as phenyl, tolyl, xylyl or naphthyl; an aralkyl group such as benzyl or phenethyl; an alkyl group substituted with a halogen such as chloromethyl, 3-chloropropyl or 3,3,3-trifluoropropyl; and the like.

[0069] When the pressure-sensitive adhesive layer is a vertically oriented pressure-sensitive adhesive layer, the surface energy of the pressure-sensitive adhesive can be 16mN / m or less. The lower limit of the surface energy can be, for example, 5mN / m or more. When the pressure-sensitive adhesive layer is a horizontally oriented pressure-sensitive adhesive layer, the surface energy can be greater than 16mN / m. The upper limit of the surface energy can be, for example, 50mN / m or less. The surface energy can be measured using a drop shape analyzer (DSA100 product of KRUSS). Specifically, deionized water with known surface tension is dropped on the surface of the pressure-sensitive adhesive to obtain a process of contact angle and is repeated 5 times, thereby obtaining the mean value of five contact angle values ​​of obtained, similarly, diiodomethane with known surface tension is dropped thereon to obtain a process of contact angle and is repeated 5 times, thereby obtaining the mean value of five contact angle values ​​of obtained. Then, the mean value of the contact angle of the deionized water and diiodomethane obtained is used to obtain surface energy by the Owens-Wendt-Rabel-Kaelble method by substituting the numerical value (Strom value) of the surface tension of the solvent. The surface energy (γ) of a sample can be calculated by considering the dispersion forces between nonpolar molecules and the interaction forces between polar molecules. 表面 )(γ 表面 =γ 色散 +γ 极性 ), where the surface energy (γ 表面 ) in the polar term (γ 极性 ) can be defined as the polarity of the surface.

[0070] The upper substrate and the lower substrate of the liquid crystal cell can be attached by a pressure-sensitive adhesive layer. Specifically, the pressure-sensitive adhesive layer of the upper substrate and the spacer of the lower substrate can be attached. When the alignment film is formed on the spacer of the lower substrate, the region of the alignment film corresponding to the spacer can be attached to the pressure-sensitive adhesive layer of the upper substrate.

[0071] The liquid crystal layer may include a liquid crystal compound. As the liquid crystal compound, a liquid crystal compound capable of changing the alignment direction by applying an external action may be used. In this specification, the term "external action" may mean all external factors that may affect the behavior of the material included in the liquid crystal layer, such as an external voltage, etc. Therefore, a state without any external action may mean a state where no external voltage, etc. is applied.

[0072] The type and physical properties of the liquid crystal compound can be appropriately selected in consideration of the purpose of the present application. In one example, the liquid crystal compound may be a nematic liquid crystal or a smectic liquid crystal. Nematic liquid crystal may mean a liquid crystal in which rod-like liquid crystal molecules are arranged in parallel in the long axis direction of the liquid crystal molecules, but there is no regularity in their positions. Smectic liquid crystal may mean a liquid crystal in which rod-like liquid crystal molecules are regularly arranged to form a lamellar structure and are regularly arranged in parallel in the long axis direction. According to one example of the present application, the liquid crystal compound may be a nematic liquid crystal compound.

[0073] As a nematic liquid crystal compound, such a liquid crystal compound can be selected: it has, for example, a clearing point of 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 has a phase transition point within the above range (i.e., a phase transition point from a nematic phase to an isotropic phase). In one example, the clearing point or phase transition point can be about 160°C or lower, 150°C or lower, or about 140°C or lower.

[0074] The liquid crystal compound may be a non-reactive liquid crystal compound. The non-reactive liquid crystal compound may mean a liquid crystal compound having no polymerizable group. The polymerizable group may be exemplified by an acryloyl group, an acryloyloxy group, a methacryloyl group, a methacryloyloxy group, a carboxyl group, a hydroxyl group, a vinyl group, or an epoxy group, but is not limited thereto, and may include a functional group considered to be a polymerizable group.

[0075] The dielectric anisotropy of the liquid crystal compound can be positive or negative. The absolute value of the dielectric anisotropy of the liquid crystal compound can be appropriately selected in consideration of the purpose 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 the liquid crystal. In this specification, the term horizontal dielectric constant (ε / / ) means the dielectric constant value measured along the direction of the electric field when a voltage is applied so that the director of the liquid crystal is substantially horizontal to the direction of the electric field caused by the applied voltage, and the vertical dielectric constant (ε⊥) means the dielectric constant value measured along the direction of the electric field when a voltage is applied so that the director of the liquid crystal is substantially perpendicular to the direction of the electric field caused by the applied voltage. The dielectric anisotropy of the liquid crystal molecule can be in the range of 5 to 25.

[0076] The refractive index anisotropy of the liquid crystal compound can be appropriately selected in consideration of the purpose of the present application. In the present specification, the term "refractive index anisotropy" may mean the difference between the extraordinary refractive index and the ordinary refractive index of the liquid crystal compound. 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 greater, 0.05 or greater, or 0.07 or greater, and may be 0.3 or less, 0.2 or less, 0.15 or less, or 0.13 or less.

[0077] The liquid crystal layer may further include a dichroic dye. When the liquid crystal layer includes a dichroic dye, even if the liquid crystal cell includes a pressure-sensitive adhesive layer, it is less affected by fluctuations in the cell gap during the bonding process of the outer substrate, and thus has an advantage that the thickness of the intermediate layer for ensuring structural stability and quality uniformity of the liquid crystal cell can be relatively thin.

[0078] The dichroic dye can control the variable transmittance property of the liquid crystal layer. In the present specification, the term "dye" may mean a material that can strongly absorb and / or deform light in at least a part or all of the visible light region (for example, in the wavelength range of 400 nm to 700 nm), and the term "dichroic dye" may mean a material that can anisotropically absorb light in at least a part or all of the visible light region.

[0079] The liquid crystal layer comprising a liquid crystal compound and a dichroic dye may be a GHLC layer (guest host liquid crystal layer). In the present specification, "GHLC layer (guest host liquid crystal layer)" may mean that the dichroic dye is arranged together according to the arrangement of the liquid crystal compound so as to exhibit anisotropic light absorption characteristics relative to the alignment direction of the dichroic dye and the direction perpendicular to the alignment direction, respectively. Functional layer. For example, a dichroic dye is a substance whose light absorptivity varies with the polarization direction, wherein if the absorptivity of light polarized in the long axis direction is large, it may be referred to as a p-type dye, and if the absorptivity of light polarized in the short axis direction is large, it may be referred to as an n-type dye. In one example, when a p-type dye is used, polarized light vibrating in the long axis direction of the dye may be absorbed, while polarized light vibrating in the short axis direction of the dye may be less absorbed and transmitted. In the following, unless otherwise specified, the dichroic dye is considered to be a p-type dye.

[0080] As a dichroic dye, for example, a known dye known to have a property of being able to align according to the orientation state of a liquid crystal compound by a 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, quarterrylene dyes, benzothiadiazole dyes, diketopyrrolopyrrole dyes, squarylium dyes or pyromethene dyes, etc., but the dyes applicable to the present application are not limited thereto.

[0081] As the dichroic dye, a dye having a dichroic ratio (i.e., a value obtained by dividing the absorption of polarized light parallel to the long axis direction of the dichroic dye by the absorption of polarized light parallel to the direction perpendicular to the long axis direction) of 5 or more, 6 or more, or 7 or more can be used. The dye may satisfy the dichroic ratio at at least part of the wavelength or any wavelength in the wavelength range of the visible light region (e.g., in the wavelength range of about 380 nm to 700 nm, or about 400 nm to 700 nm). The upper limit of the dichroic ratio may be, for example, approximately 20 or less, 18 or less, 16 or less, or 14 or less.

[0082] The content of dichroic dye in the liquid crystal layer can be appropriately selected considering the purpose of the present application. For example, the content of dichroic dye in the liquid crystal layer can be 0.2 weight % or more. The content of dichroic dye can be specifically 0.5 weight % or more, 1 weight % or more, 2 weight % or more, or 3 weight % or more. The upper limit of the content of dichroic dye can be, for example, 10 weight % or less, 9 weight % or less, 8 weight % or less, 6 weight % or less, or 5 weight % or less. When the content of dichroic dye in the liquid crystal layer is too little, it may be difficult to show the desired transmittance variable characteristics, and it may not be enough to reduce the thickness of the adhesive layer for reducing the cell gap fluctuation that may occur during the bonding process of the outer substrate. At the same time, when the content of dichroic dye in the liquid crystal layer is too large, there is a risk of precipitation. Therefore, the content of dichroic dye can be advantageous within the above range.

[0083] The thickness of the liquid crystal layer is not particularly limited, and for example, the thickness of the liquid crystal layer may be about 0.01 μm or more, 0.05 μm or more, 0.1 μm or more, 0.5 μm or more, 1 μm or more, 1.5 μm or more, 2 μm or more, 2.5 μm or more, 3 μm or more, 3.5 μm or more, 4 μm or more, 4.5 μm or more, 5 μm or more, 5.5 μm or more, 6 μm or more, 6.5 μm or more, 7 μm or more, 7.5 μm or more, 8 μm or more, 8.5 μm or more, 9 μm or more, or 9.5 μm or more. The upper limit of the thickness of the liquid crystal layer is not particularly limited, and it may generally be about 30 μm or less, 25 μm or less, 20 μm or less, or 15 μm or less.

[0084] The liquid crystal layer can be switched between a first orientation state and a second orientation state different from the first orientation state. The switching can be regulated, for example, by applying external energy such as voltage. For example, the liquid crystal layer can maintain any one of the first orientation state and the second orientation state in a state where no voltage is applied, and can be switched to another orientation state by voltage application.

[0085] In one example, the first alignment state may be a twisted alignment state, that is, the liquid crystal layer may be switched between the twisted alignment and an alignment state different from the twisted alignment by applying external energy.

[0086] In one example, the liquid crystal layer can be switched between a twisted alignment state and a vertical alignment state. In one example, the liquid crystal layer can be in a vertical alignment state when no voltage is applied, and can be in a twisted alignment state when a voltage is applied.

[0087] In the present specification, the "vertical orientation state" is a state in which the director of the liquid crystal compound in the liquid crystal layer is arranged substantially vertically to the plane of the liquid crystal layer, wherein, for example, the angle formed by the director of the liquid crystal compound relative to the plane of the liquid crystal layer may be, for example, in the range of about 80 to 100 degrees or 85 to 95 degrees, or it may form approximately 90 degrees.

[0088] In the present specification, "twisted orientation state" may mean a spiral structure in which the director of the liquid crystal compound in the liquid crystal layer is twisted along an imaginary spiral axis to form a layer and oriented. The twisted orientation state may be realized in a vertical orientation state, a horizontal orientation state, or a tilted orientation state. That is, the vertical twisted orientation mode is a state in which each liquid crystal compound is twisted along the spiral axis in a vertical orientation state to form a layer; the horizontal twisted orientation mode is a state in which each liquid crystal compound is twisted along the spiral axis in a horizontal orientation state to form a layer; and the tilted twisted orientation mode is a state in which each liquid crystal compound is twisted along the spiral axis in a tilted orientation state to form a layer. According to the present application, the twisted orientation state may be a twisted orientation state of the horizontal orientation state.

[0089] In the twisted orientation state, the ratio (d / p) of the thickness (d) of the liquid crystal layer to the pitch (pitch, p) may be 20 or less, and the lower limit may be 0.5 or more. When the ratio (d / p) of the thickness (d) to the pitch (p) in the twisted orientation state is within the above range, the optical device may exhibit excellent light transmittance variable characteristics even in the absence of any polarizer. Generally, when the ratio d / p is 0.7 or more and less than 2.5, it may be referred to as an STN (super twisted nematic) mode, and when the ratio d / p is 2.5 or more, it may be referred to as an HTN (highly twisted nematic) drive mode.

[0090] The pitch (p) of the liquid crystal layer can be measured by a measurement method using a wedge cell, and specifically, can be measured 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, 789-791). The ratio (d / p) can be achieved by introducing an appropriate amount of chiral dopant into the liquid crystal layer.

[0091] The liquid crystal layer may also include a chiral dopant, and when the liquid crystal layer includes a chiral agent, a twisted orientation state may be achieved. The chiral agent (or chiral dopant) that may be included in the liquid crystal layer may be used without particular limitation, as long as it may cause the desired rotation (twist) without deteriorating the liquid crystal properties, such as nematic regularity. The chiral agent used to cause rotation in the liquid crystal compound needs to include at least chirality in the molecular structure. The chiral agent may be exemplified by: for example, a compound having one or two or more asymmetric carbons; a compound having an asymmetric point on a heteroatom, such as a chiral amine or a chiral sulfoxide; or a compound having an axial asymmetry and an optically active site, such as a cumulative polyene or a binaphthol. The chiral agent may be, for example, a low molecular weight compound having a molecular weight of 1,500 or less. As a chiral agent, commercially available chiral nematic liquid crystals may also be used, for example, chiral dopant liquid crystal S-811 commercially available from Merck Co., Ltd. or LC756 of BASF.

[0092] The application ratio of the chiral dopant is selected so that the desired ratio (d / p) can be achieved. Generally, the content (weight %) of the chiral dopant can be calculated by the formula 100 / HTP (helical twisting power) × pitch (p) (nm). HTP represents the twisting strength of the chiral dopant, wherein the content of the chiral dopant can be determined by referring to the above method considering the desired pitch.

[0093] The upper substrate of the liquid crystal cell may further include a first electrode layer 10b between the first base layer 10a and the pressure-sensitive adhesive layer 10c. The first electrode layer 10b may contact the inner surface of the first base layer 10a. The pressure-sensitive adhesive layer 10c may contact 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 contact the inner surface of the second base layer 20a. The spacer 20c may contact the inner surface of the second electrode layer 20b.

[0094] The first electrode layer and the second electrode layer can be used to provide an external effect such as the application of an electric field so that the material contained in the liquid crystal layer transmits or blocks incident light. In one example, the first electrode layer and / or the second electrode layer can include a conductive polymer, a conductive metal, a conductive nanowire, or a metal oxide such as ITO (indium tin oxide), etc., but is not limited thereto. The upper electrode layer and / or the lower second electrode layer can be formed by, for example, depositing a conductive polymer, a conductive metal, a conductive nanowire, or a metal oxide such as ITO (indium tin oxide).

[0095] 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 top surface portion and / or the side surface portion of the spacer 20c may contact the alignment film. The lower surface portion of the spacer 20c may contact the second electrode layer 20b. Since the pressure-sensitive adhesive layer included in the upper substrate may have a liquid crystal orientation, the upper substrate may not include the alignment film. That is, the alignment film may not be included on the inner side surface of the first electrode layer 10b.

[0096] In this specification, the combination of the first base layer, the first electrode layer and the pressure-sensitive adhesive layer may be referred to as an upper substrate, and the combination of the second base layer, the second electrode layer, the spacer and the alignment film may be referred to as a lower substrate. In the liquid crystal cell, the upper substrate may not include a separate alignment film other than the pressure-sensitive adhesive layer, and the lower substrate may include the alignment film.

[0097] 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 the present specification, "horizontal alignment film" may mean a layer containing an alignment material that imparts a horizontal alignment force to the liquid crystal compounds present in the adjacent liquid crystal layer. In the present specification, "vertical alignment film" may mean a layer containing an alignment material that imparts a vertical alignment force to the liquid crystal compounds present in the adjacent liquid crystal layer. The pretilt angle of the adjacent liquid crystal compounds relative to the vertical alignment film may be in the range of 80 to 90 degrees, 85 to 90 degrees, or about 87 to 90 degrees, and the pretilt angle of the adjacent liquid crystal compounds relative to the horizontal alignment film may be in the range of 0 to 10 degrees, 0 to 5 degrees, or 0 to 3 degrees. Unlike the pressure-sensitive adhesive layer, the alignment film may not have an adhesive force for bonding the upper substrate and the lower substrate. In one example, in Figure 2 In a state of the liquid crystal unit, the alignment film can have a peeling force close to zero relative to the first base layer.

[0098] The alignment film may be a rubbing alignment film or a photo-alignment film. The orientation direction of the alignment film may be a rubbing direction in the case of a rubbing alignment film, and may be a direction of polarized light to be irradiated in the case of a photo-alignment film, wherein such an orientation direction may be determined by a detection method using an absorbing linear polarizer. Specifically, the orientation direction may be determined by: in a state where the liquid crystal compound contained in the liquid crystal layer is horizontally oriented, an absorbing linear polarizer is disposed on one side of the liquid crystal layer, and the transmittance is measured while the polarizer is rotated 360 degrees. When light is irradiated to one side of the liquid crystal layer or the absorbing linear polarizer in the above state and the brightness (transmittance) is measured from the other side at the same time, if the absorption axis or the transmission axis is consistent with the orientation direction of the liquid crystal alignment film, the transmittance tends to be low, wherein the orientation direction may be determined by a simulation reflecting the refractive index anisotropy of the applied liquid crystal compound, etc. The method of determining the orientation direction according to the pattern of the liquid crystal layer is known, and in the present application, the orientation direction of the alignment film may be determined by such a known method.

[0099] The alignment film may include one or more selected from the following: materials known to exhibit orientation ability through friction orientation, such as polyimide compounds, poly(vinyl alcohol) compounds, poly(amic acid) compounds, polystyrene compounds, polyamide compounds and polyoxyethylene compounds; or materials known to exhibit orientation ability through light irradiation, such as polyimide compounds, polyamic acid compounds, polynorbornene compounds, phenylmaleimide copolymer compounds, polyvinyl cinnamate compounds, polyazobenzene compounds, polyethyleneimide compounds, polyvinyl alcohol compounds, polyamide compounds, polyethylene compounds, polystyrene compounds, polyphenylene phthalamide compounds, polyester compounds, CMPI (chloromethylated polyimide) compounds, PVCI (polyvinylcinnamate) compounds and polymethyl methacrylate compounds, but are not limited thereto.

[0100] The spacer 20c may maintain a gap between the upper substrate and the lower substrate. A liquid crystal layer may exist in a region where no spacer exists between the upper substrate and the lower substrate.

[0101] The spacer may be a patterned spacer. The spacer may have a column shape or a partition wall shape. In one example, the spacer may have a partition wall shape. When the spacer has a partition wall shape, it may be advantageous in maintaining the height of the liquid crystal cell and improving the physical rigidity of the liquid crystal cell. The partition wall may separate the space between the lower substrate and the upper substrate into two or more spaces. In the region where the spacer is not present, other films or other layers present in the lower portion may be exposed. For example, the second electrode layer may be exposed in the region where the spacer is not present. The alignment film may cover the spacer and the second electrode layer exposed in the region where the spacer is not present. In a liquid crystal cell in which the upper substrate and the lower substrate are bonded together, the alignment film present on the spacer of the lower substrate and the pressure-sensitive adhesive layer of the upper substrate may contact each other.

[0102] Liquid crystal compounds and the above-mentioned additives, such as dichroic dyes, chiral agents, etc., may be present in the region between the upper substrate and the lower substrate where no spacer exists. The shape of the spacer is not particularly limited, and it can be applied without limitation to a polyhedron having, for example, a circular, elliptical, or other polygonal shape.

[0103] The spacer may include a curable resin. The type of curable resin is not particularly limited, wherein, for example, a thermosetting resin or a photocurable resin such as an ultraviolet curable resin may be used. As a thermosetting resin, for example, a silicone resin, a silicone resin, a furan resin, a polyurethane resin, an epoxy resin, an amino resin, a phenolic resin, a urea resin, a polyester resin, or a melamine resin, etc. may be used, but not limited thereto. As an ultraviolet curable resin, an acrylic polymer may be generally used, such as a polyester acrylate polymer, a polystyrene acrylate polymer, an epoxy acrylate polymer, a polyurethane acrylate polymer or a polybutadiene acrylate polymer, a silicone acrylate polymer or an alkyl acrylate polymer, etc., but not limited thereto.

[0104] The spacer can be formed by a patterning process. For example, the spacer can be formed by a photolithography process. The photolithography process may include a process of applying a curable resin composition on a base layer or an electrode layer, and then irradiating it with ultraviolet light via a pattern mask. The pattern mask can be patterned into an ultraviolet transmission area and an ultraviolet blocking area. The photolithography process may also include a process of washing the curable resin composition irradiated by ultraviolet light. The area irradiated by ultraviolet light is cured, and the area not irradiated by ultraviolet light remains in a liquid phase so that it is removed by a washing process, thereby patterning it into a partition wall shape. In the photolithography process, after ultraviolet irradiation, the pattern mask can be subjected to a release treatment to easily separate the resin composition from the pattern mask, or a release paper can be placed between the layer of the resin composition and the pattern mask.

[0105] The width (line width), spacing (pitch), thickness and area of ​​the spacer can be appropriately selected within the scope of not damaging the purpose of the present application. For example, the width (line width) of the spacer can be in the range of 10μm to 500μm or in the range of 10μm to 50μm. The spacing (pitch) of the spacer can be in the range of 10μm to 1000μm or in the range of 100μm to 1000μm. Relative to 100% of the total area of ​​the second base layer, the area of ​​the spacer can be about 5% or more, and can be 50% or less. When the area of ​​the spacer is within the above range, it can be beneficial to ensure excellent electro-optical properties while fully ensuring the adhesion between the upper substrate and the lower substrate. The thickness range of the spacer can be, for example, 1μm to 30μm or 3μm to 20μm.

[0106] In order to overcome the physical limitations of the liquid crystal cell, the outer substrates may be bonded together via adhesive layers on both sides of the liquid crystal cell, but due to the low modulus of the pressure-sensitive adhesive layer, it is easily affected by external pressure, whereby defects such as cell gap collapse or liquid crystal flow or aggregation may occur. The thickness of the adhesive layer included in the optical device is controlled, whereby defects can be minimized and structural stability and uniform appearance characteristics of the optical device can be ensured.

[0107] As an example, the total thickness of the adhesive layers included in the optical device may be 200 μm or more. The total thickness of the adhesive layers may refer to the sum of the thicknesses of all adhesive layers included in the optical device, for example, Figure 1 In the case of a structure of, it may mean the sum of the thicknesses of the first adhesive layer and the second adhesive layer. Figure 2 and Figure 4 In the case of a structure of, it may mean the sum of the thicknesses of the first adhesive layer, the second adhesive layer, the third adhesive layer, and the fourth adhesive layer, or Figure 3 In the case of a structure of, it may mean the sum of the thicknesses of the first adhesive layer, the second adhesive layer, the third adhesive layer, the fourth adhesive layer, the fifth adhesive layer, and the sixth adhesive layer. When the total thickness of the adhesive layer is within the above range, the structural stability and uniform appearance characteristics of the optical device can be ensured by minimizing defects during the bonding process of the outer substrate. The sum of the total thickness of the adhesive layer 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 thickness of the adhesive layer 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 too thick, the electro-optical properties of the optical device, such as the transmittance properties, may deteriorate, so the total thickness may be advantageous within the above range.

[0108] The first to sixth adhesive layers may each have a single-layer structure of an adhesive layer or may be a laminate of two or more sub-adhesive layers. The thickness and quantity of the sub-adhesive layers may be controlled in consideration of the desired thickness of the adhesive layer. In an example, the thickness of the single-layer adhesive layer or the sub-adhesive layer may be in the range of 100 μm to 500 μm or in the range of 300 μm to 400 μm.

[0109] As an example, the Young's modulus (E) of the first adhesive layer to the sixth adhesive layer can be each in the range of 0.1MPa to 100MPa. As another example, the Young's modulus (E) of the first adhesive layer to the sixth adhesive layer can be 0.2MPa or larger, 0.4MPa or larger, 0.6MPa or larger, 0.8MPa or larger, 1MPa or larger, 5MPa or larger, or about 10MPa or larger, and can be about 95MPa or smaller, 80MPa or smaller, 75MPa or smaller, 70MPa or smaller, 65MPa or smaller, 60MPa or smaller, 55MPa or smaller, or about 50MPa or smaller. Young's modulus (E) can be measured in the manner specified in ASTM D882, for example, and can be used to cut film in the form provided by relevant standards and measure the equipment of stress-strain curve (power and length can be measured simultaneously), such as UTM (universal testing machine) is measured. When the Young's modulus of the adhesive layer included in the optical device is within the above range, it can be more conducive to ensuring excellent durability of the optical device. When the adhesive layer is a laminate of at least two or more sub-adhesive layers, each of the sub-adhesive layers can satisfy the above Young's modulus range.

[0110] As an example, the thermal expansion coefficients of the first to sixth adhesive layers may each be 2,000 ppm / K or less. In another example, 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 may be 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 adhesive layer can be measured according to the provisions of ASTM D696, wherein the thermal expansion coefficient can be calculated by cutting it in the form provided by the relevant standards and measuring the length change per unit temperature, and can be measured by known methods such as TMA (thermomechanical analysis). When the thermal expansion coefficient of the adhesive layer included in the optical device is within the above range, it can be more conducive to ensuring the excellent durability of the optical device. When the adhesive layer is a laminate of at least two or more sub-adhesive layers, each sub-adhesive layer can meet the scope of the thermal expansion coefficient.

[0111] The first to sixth adhesive layers may each be a thermoplastic polyurethane (TPU) adhesive layer, a polyamide adhesive layer, a polyester adhesive layer, an EVA (ethylene vinyl acetate) adhesive layer, an acrylic adhesive layer, a silicone adhesive layer or a polyolefin adhesive layer. According to an example of the present application, at least one or more adhesive layers may each be a thermoplastic polyurethane.

[0112] The optical device may further include an outer layer surrounding a side surface of the liquid crystal cell. Figure 1An optical device including an outer layer 600 is exemplarily shown. In the optical device, the top area of ​​the liquid crystal cell may be smaller than the top area of ​​the first outer substrate or the second outer substrate. In addition, the top area of ​​the liquid crystal cell may be smaller than the top areas of the first to sixth adhesive layers included in the optical device. In one example, the liquid crystal cell may be encapsulated by a first adhesive layer positioned between the first outer substrate and the first polarizer, a second adhesive layer positioned between the second outer substrate and the second polarizer, and an outer layer. In the present application, the term encapsulation may mean covering the entire surface of the liquid crystal cell with the adhesive layer and the outer layer. In one example, when there is no additional layer between the first adhesive layer and the second adhesive layer, the first adhesive layer and the second adhesive layer may directly contact the liquid crystal cell. In another example, when there is no additional layer between the first adhesive layer and the second adhesive layer, the liquid crystal cell may directly contact the additional layer. According to Figure 1 The upper surface of the liquid crystal unit can contact the first buffer layer 301, the lower surface can contact the second buffer layer 302, and the side surface can contact the outer layer 600. According to the desired structure, for example, the encapsulation structure can be realized by a method of compacting a laminate under a vacuum state, wherein the laminate sequentially includes a first outer substrate, a first adhesive layer, a first polarizer, a liquid crystal unit, a second polarizer, a second adhesive layer, and a second outer substrate, and includes an outer layer surrounding the side surface of the liquid crystal unit. Through such an encapsulation structure, the durability and weather resistance of the optical device are greatly improved, and therefore, it can be stably applied to outdoor applications such as skylights.

[0113] The outer layer may include, for example, a thermoplastic polyurethane (TPU) adhesive, a polyamide adhesive, a polyester adhesive, an EVA (ethylene vinyl acetate) 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 adhesive layer.

[0114] The present application also relates to a method for manufacturing an optical device. The method for manufacturing an optical device may include the following steps: preparing a laminate, the laminate sequentially including a first outer substrate, a first adhesive layer, a first polarizer, a liquid crystal cell, a second polarizer, a second adhesive layer, and a second outer substrate, and further including a first buffer layer positioned between the first base layer and the first outer substrate; and autoclaving the laminate. Unless otherwise specified in the method for manufacturing an optical device, the contents described in the optical device may be equally applied.

[0115] The laminate may further include an outer layer surrounding the side surfaces of the liquid crystal cell.

[0116] When the optical device further includes other elements in addition to the liquid crystal cell and the polarizer, the laminate may further include other elements in addition to the liquid crystal cell and the polarizer at desired positions.

[0117] The autoclave process may be performed by applying heat and / or pressure to the laminate formed after the lamination step.

[0118] The conditions of the autoclave process are not particularly limited, and it can be carried out at an appropriate temperature and pressure, for example, according to the type of adhesive layer applied. The temperature of a typical autoclave process is about 80°C or higher, 90°C or higher, 100°C or higher, and the pressure is 2 atmospheres or more, but is not limited thereto. The upper limit of the process temperature may be approximately 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 may be approximately about 10 atmospheres or less, 9 atmospheres or less, 8 atmospheres or less, 7 atmospheres or less, or 6 atmospheres or less.

[0119] Such an optical device can be used in various applications, and for example, can be used for eyewear such as sunglasses or AR (augmented reality) or VR (virtual reality) eyewear, building facades, or vehicle sunroofs, etc. In one example, the optical device itself can be a vehicle sunroof. For example, in a car including a car body having at least one opening formed therein, the optical device or vehicle sunroof attached to the opening can be installed and used.

[0120] Beneficial Effects

[0121] The optical device of the present application can properly maintain the cell gap of the liquid crystal cell, has excellent adhesion between the upper substrate and the lower substrate, and solves the light leakage caused by the irregular arrangement of liquid crystals occurring when external impact occurs. BRIEF DESCRIPTION OF THE DRAWINGS

[0122] Figure 1 An optical device of a first example of the present application is exemplarily shown.

[0123] Figure 2 An optical device according to a second example of the present application is exemplarily shown.

[0124] Figure 3 An optical device according to a third example of the present application is exemplarily shown.

[0125] Figure 4 An optical device of a fourth example of the present application is exemplarily shown.

[0126] Figure 5 The liquid crystal cell of the present application is exemplarily shown.

[0127] Figure 6 The optical device of Comparative Example 1 is exemplarily shown.

[0128] Figures 7a to 7e The loss elastic modulus at each frequency of the pressure-sensitive adhesive layer, buffer layer, and adhesive layer used in Examples and Comparative Examples is shown.

[0129] Figures 8a to 8e The storage elastic modulus at each frequency of the pressure-sensitive adhesive layer, buffer layer, and adhesive layer used in Examples and Comparative Examples is shown. DETAILED DESCRIPTION

[0130] Hereinafter, the present application is specifically described through the following examples, but the scope of the present application is not limited by the following examples.

[0131] Measurement Example 1. Measurement of storage elastic modulus and loss elastic modulus

[0132] The storage elastic modulus and loss elastic modulus were measured using TA's ARES G2 rheometer. Specifically, the pressure-sensitive adhesive layer, adhesive layer and buffer layer used in the embodiments and comparative examples were prepared as circular samples (diameter: 8 mm, thickness: 600 μm), respectively. For the circular sample, the axial force was set to 50 gf (vertical force) at a temperature of 25°C using an ARES G2 parallel plate (Al plate), and then the loss elastic modulus and storage elastic modulus were measured while changing the frequency from 0.6 radians / second to 100 radians / second (frequency sweep) under a strain of 5%, and the results are shown in Figures 7a to 7e and Figures 8a to 8e In addition, the loss elastic modulus values ​​and storage elastic modulus values ​​at 1 Hz and 10 Hz are described in Table 1. In the measuring device, both the elastic modulus value for the radian / second frequency and the elastic modulus value for the Hz frequency can be obtained, wherein regarding the numerical value of the measuring device, 1 Hz is about 6.30957 radian / second, and 10 Hz is about 63.0957 radian / second.

[0133] Example 1.

[0134] Fabrication of Liquid Crystal Cells

[0135] As the first base layer, a polycarbonate film (Keiwa) having a thickness of about 100 μm and a width × height area of ​​300 mm × 300 mm was prepared. The first electrode layer was formed by depositing ITO (indium tin oxide) to a thickness of 50 nm on the first base layer. A pressure-sensitive adhesive composition (KR-3700, Shin-Etsu) was applied to the first electrode layer and then dried at about 150 ° C for about 5 minutes to form a pressure-sensitive adhesive layer having a thickness of about 10 μm. The loss elastic modulus of the pressure-sensitive adhesive layer at a frequency of 1 Hz was 906,687 Pa. The combination of the first base layer, the first electrode layer, and the pressure-sensitive adhesive layer is referred to as an upper substrate.

[0136] As the second base layer, a polycarbonate film (Keiwa) with a thickness of about 100 μm and a width × height area of ​​300 mm × 300 mm was prepared. The second electrode layer was formed by depositing ITO (indium tin oxide) to a thickness of 50 nm on the second base layer. An acrylic resin composition (KAD-03, Minutatec) was coated on the second electrode layer, and then a honeycomb type spacer was formed by photolithography. The regular hexagons (closed island shapes) constituting the honeycomb have a pitch of about 350 μm, a height of about 6 μm, and a line width of about 30 μm. A vertical alignment film (Nissan, 5661) was coated on the spacer to a thickness of about 300 nm and then rubbed in one direction. The combination of the second base layer, the second electrode layer, the spacer, and the vertical alignment film is referred to as the lower substrate.

[0137] A liquid crystal composition was coated on the vertical alignment film of the lower substrate to form a liquid crystal layer, and then a liquid crystal cell was prepared by laminating a pressure-sensitive adhesive layer of the upper substrate to face the coating surface of the liquid crystal composition. 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.

[0138] Optical device manufacturing

[0139] A laminate is prepared, the laminate sequentially comprising a first outer substrate, a first adhesive layer, a first polarizer, a first buffer layer, the prepared liquid crystal cell, a second buffer layer, a second polarizer, a second adhesive layer, and a second outer substrate, and comprising an outer layer surrounding the side surface of the liquid crystal cell. The second outer substrate is arranged in the direction of gravity relative to the first outer substrate.

[0140] As each of the first outer substrate and the second outer substrate, a flat glass having a thickness of about 3 mm and an area of ​​width×length=350 mm×350 mm was used. A TPU layer (Argotec) having a thickness of 380 μm was used for each of the first adhesive layer, the second adhesive layer, and the outer layer. The loss elastic modulus of the TPU layer (Argotec) at a frequency of 1 Hz was 1,485,510 Pa. As each of the first buffer layer and the second buffer layer, an OCA (optically clear adhesive) layer M1 having a thickness of 500 μm and a loss elastic modulus of 9,696 Pa at a frequency of 1 Hz was used.

[0141] The laminate is made by subjecting the laminate to an autoclave process at a temperature of about 110°C and a pressure of about 2 atmospheres. Figure 1 The structure of the optical device.

[0142] Example 2

[0143] An optical device was manufactured in the same method as in Example 1, except that in Example 1, an OCA layer M2 having a thickness of 500 μm and a loss elastic modulus of 17,340 Pa at a frequency of 1 Hz was used as each of the first buffer layer and the second buffer layer.

[0144] Example 3

[0145] An optical device was manufactured in the same method as in Example 1, except that in Example 1, an OCA layer M3 having a thickness of 500 μm and a loss elastic modulus of 23,434 Pa at a frequency of 1 Hz was used as each of the first buffer layer and the second buffer layer.

[0146] Example 4

[0147] An optical device was manufactured in the same method as in Example 1, except that in Example 1, an OCA layer M4 having a thickness of 500 μm and a loss elastic modulus of 46,158 Pa at a frequency of 1 Hz was used as each of the first buffer layer and the second buffer layer.

[0148] Example 5

[0149] An optical device was manufactured in the same method as in Example 1, except that in Example 1, an OCA layer M5 having a thickness of 500 μm and a loss elastic modulus of 56,571 Pa at a frequency of 1 Hz was used as each of the first buffer layer and the second buffer layer.

[0150] Example 6

[0151] In the same manner as in Example 1, a liquid crystal cell was prepared.

[0152] A laminate is prepared, the laminate sequentially comprising a first outer substrate, a first adhesive layer, a first buffer layer, a first polarizer, a third adhesive layer, a prepared liquid crystal cell, a fourth adhesive layer, a second polarizer, a second buffer layer, a second adhesive layer, and a second outer substrate. The second outer substrate is arranged in the direction of gravity relative to the first outer substrate.

[0153] As the first outer substrate and the second outer substrate, the same outer substrate as that of Example 1 was used.

[0154] As the first adhesive layer, the second adhesive layer, the third adhesive layer, and the fourth adhesive layer, the same adhesive layers as the first adhesive layer and the second adhesive layer of Example 1 were used.

[0155] As the first buffer layer and the second buffer layer, an OCA layer M2 having a thickness of 500 μm was used, which was the same as in Example 2. The first buffer layer and the second buffer layer were formed by laminating pressure-sensitive adhesive layers on the outer side of the first polarizer and the outer side of the second polarizer, respectively.

[0156] The laminate is made by subjecting the laminate to an autoclave process at a temperature of about 110°C and a pressure of about 2 atmospheres. Figure 2 The structure of the optical device.

[0157] Example 7

[0158] An optical device was manufactured in the same method as in Example 6, except that in Example 6, an OCA layer M2 having a thickness of 400 μm was used as each of the first buffer layer and the second buffer layer.

[0159] Example 8

[0160] An optical device was manufactured in the same method as in Example 6, except that in Example 6, an OCA layer M2 having a thickness of 300 μm was used as each of the first buffer layer and the second buffer layer.

[0161] Example 9

[0162] An optical device was manufactured in the same method as in Example 6, except that in Example 6, an OCA layer M2 having a thickness of 200 μm was used as each of the first buffer layer and the second buffer layer.

[0163] Example 10

[0164] An optical device was manufactured in the same method as in Example 6, except that in Example 6, an OCA layer M2 having a thickness of 100 μm was used as each of the first buffer layer and the second buffer layer.

[0165] Embodiment 11

[0166] In the same manner as in Example 1, a liquid crystal cell was prepared.

[0167] A laminate is prepared, the laminate sequentially comprising a first outer substrate, a first adhesive layer, a first buffer layer, a fifth adhesive layer, a first polarizer, a third adhesive layer, a prepared liquid crystal cell, a fourth adhesive layer, a second polarizer, a sixth adhesive layer, a second buffer layer, a second adhesive layer, and a second outer substrate. The second outer substrate is arranged in the direction of gravity relative to the first outer substrate.

[0168] As the first outer substrate and the second outer substrate, the same outer substrate as that of Example 1 was used.

[0169] As each of the first adhesive layer, the second adhesive layer, the third adhesive layer, the fourth adhesive layer, the fifth adhesive layer, and the sixth adhesive layer, the same adhesive layer as the first adhesive layer and the second adhesive layer of Example 1 were used.

[0170] As the first buffer layer and the second buffer layer, an OCA layer M3 having a thickness of 500 μm was used, which was the same as in Example 3. The first buffer layer and the second buffer layer were formed by laminating a pressure-sensitive adhesive layer on the inner side of the first adhesive layer and the inner side of the second adhesive layer, respectively.

[0171] The laminate is made by subjecting the laminate to an autoclave process at a temperature of about 110°C and a pressure of about 2 atmospheres. Figure 3 The structure of the optical device.

[0172] Example 12

[0173] In the same manner as in Example 1, a liquid crystal cell was prepared.

[0174] A laminate is prepared, the laminate sequentially comprising a first outer substrate, a first adhesive layer, a first buffer layer, a first polarizer, a third adhesive layer, a prepared liquid crystal cell, a fourth adhesive layer, a second polarizer, a second adhesive layer, and a second outer substrate. The second outer substrate is arranged in the direction of gravity relative to the first outer substrate.

[0175] As the first outer substrate and the second outer substrate, the same outer substrate as that of Example 1 was used.

[0176] As each of the first adhesive layer, the second adhesive layer, the third adhesive layer, and the fourth adhesive layer, the same adhesive layer as the first adhesive layer and the second adhesive layer of Example 1 was used. As the first buffer layer, the same OCA layer M3 having a thickness of 500 μm as that of Example 3 was used. The first buffer layer was formed by laminating a pressure-sensitive adhesive layer on the outer side of the first polarizer.

[0177] The laminate is made by subjecting the laminate to an autoclave process at a temperature of about 110°C and a pressure of about 2 atmospheres. Figure 4 The structure of the optical device.

[0178] Comparative Example 1

[0179] In the same manner as in Example 1, a liquid crystal cell was prepared.

[0180] A laminate is prepared, the laminate sequentially comprising a first outer substrate, a first adhesive layer, a first polarizer, a third adhesive layer, a prepared liquid crystal cell, a fourth adhesive layer, a second polarizer, a second adhesive layer, and a second outer substrate, and comprising an outer layer surrounding the side surface of the liquid crystal cell. Relative to the first outer substrate, the second outer substrate is arranged in the direction of gravity. Comparative Example 1 does not include a first buffer layer and a second buffer layer.

[0181] As the first outer substrate and the second outer substrate, the same outer substrate as that of Example 1 was used.

[0182] As each of the first and second adhesive layers, a three-layer adhesive layer of a TPU layer (Argotec) having a loss elastic modulus of 1,485,510 Pa at a frequency of 1 Hz and a thickness of 380 μm was used. As each of the third and fourth adhesive layers, a layer of TPU (Argotec) having a loss elastic modulus of 1,485,510 Pa at a frequency of 1 Hz and a thickness of 380 μm was used. The TPU layer was also used as an outer layer.

[0183] The laminate is made by subjecting the laminate to an autoclave process at a temperature of about 110°C and a pressure of about 2 atmospheres. Figure 6 The structure of the optical device.

[0184] Evaluation Example 1. Flicker Amount Measurement

[0185] The flicker amount of the optical device of Examples 1 to 12 and Comparative Example 1 was measured to evaluate light leakage, and the results are described in Table 1 below. After the optical device was placed on the backlight, the flicker amount was measured using CA-310 (brightness meter of Konica MINOLTA). Using the K-9205 device of MIK21, the flicker amount was measured by reading the maximum value of the transmittance change while applying pressure at a cycle of 300g and 2Hz. This means that the smaller the flicker amount, the smaller the brightness change. In addition, Table 1 below shows the values ​​of the storage elastic modulus and the loss elastic modulus of the pressure-sensitive adhesive layer (G1), adhesive layer (G2) and buffer layer (G3) of Examples 1 to 12 and Comparative Example 1. It can be determined that compared with Comparative Example 1, Examples 1 to 12 show low flicker amounts.

[0186] [Table 1]

[0187]

[0188] [Explanation of Reference Numerals]

[0189] 101: first outer substrate, 102: second outer substrate, 200: liquid crystal unit, 301: first buffer layer, 302: second buffer layer, 401: first adhesive layer, 402: second adhesive layer, 403: third adhesive layer, 404: fourth adhesive layer, 405: fifth adhesive layer, 406: sixth adhesive layer, 501: first polarizer, 502: second polarizer, 600: outer layer, 10a: first base layer, 10b: first electrode layer, 10c: pressure-sensitive adhesive layer, 20a: second base layer, 20b: second electrode layer, 20c: spacer, 20d: alignment film, 30: liquid crystal layer

Claims

1. An optical device, comprising, in sequence, a first outer substrate, a first adhesive layer in contact with the inner surface of the first outer substrate, a liquid crystal cell, a second adhesive layer in contact with the inner surface of a second outer substrate, and the second outer substrate, wherein The liquid crystal unit comprises: an upper substrate including a first base layer and a pressure-sensitive adhesive layer; a lower substrate including a second base layer and a spacer; and a liquid crystal layer containing a liquid crystal compound between the upper substrate and the lower substrate, and The first base layer is disposed closer to the first outer substrate than the second base layer, and The optical device also includes a first buffer layer positioned between the first base layer and the first outer substrate. 2 . The optical device according to claim 1 , wherein the first outer substrate and the second outer substrate are each a glass substrate. 3 . The optical device according to claim 1 , wherein the pressure-sensitive adhesive layer has a loss elastic modulus in the range of 50,000 Pa to 2 MPa at a temperature of 25° C. and a frequency of 1 Hz. 4 . The optical device according to claim 1 , wherein a loss elastic modulus of the first buffer layer at a temperature of 25° C. and a frequency of 1 Hz is in a range of 1,000 Pa to 500,000 Pa. 5 . The optical device according to claim 1 , wherein a loss elastic modulus of the first adhesive layer and a loss elastic modulus of the second adhesive layer are each higher than a loss elastic modulus of the pressure-sensitive adhesive layer. 6 . The optical device according to claim 1 , wherein loss elastic moduli of the first adhesive layer and the second adhesive layer at a temperature of 25° C. and a frequency of 1 Hz are each in a range of 1 MPa to 100 MPa. 7 . The optical device according to claim 1 , wherein the first buffer layer is in contact with an outer surface of the first base layer, or is in contact with an inner surface of the first adhesive layer. 8 . The optical device according to claim 1 , further comprising a third adhesive layer in contact with an outer side surface of the first base layer, and a fourth adhesive layer in contact with an outer side surface of the second base layer.

9. The optical device of claim 1, further comprising 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. 10 . The optical device of claim 9 , further comprising a fifth adhesive layer in contact with an outer side surface of the first polarizer, and a sixth adhesive layer in contact with an outer side surface of the second polarizer.

11. The optical device of claim 1, further comprising a second buffer layer positioned between the second base layer and the second outer substrate. 12 . The optical device according to claim 1 , wherein the liquid crystal layer exists in a vertical alignment state when no voltage is applied, and the liquid crystal layer exists in a twisted alignment state when a voltage is applied. 13 . The optical device according to claim 1 , wherein the upper substrate further comprises a first electrode layer between the first base layer and the pressure-sensitive adhesive layer, and the lower substrate further comprises a second electrode layer between the second base layer and the spacer. 14 . The optical device according to claim 13 , wherein the upper substrate does not include an alignment film, and the lower substrate further includes an alignment film.

15. A car, comprising: An automobile body having one or more openings formed therein; and an optical device according to claim 1 mounted in the opening.

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