Optical modulation device

Abstract

The present application can provide an optical modulation device, an optical device, or a manufacturing method thereof, which can stably maintain designed optical characteristics even after a packaging process in which pressure is applied, such as an autoclave process. The present application can also provide an optical modulation device, an optical device including the same, or a manufacturing method thereof, which can stably maintain an orientation state of an optical modulation layer while effectively securing adhesion between an upper substrate and a lower substrate.

Description

Technical Field

[0001] This application claims priority to Korean Patent Application No. 10-2020-0093729, filed on July 28, 2020, the disclosure of which is incorporated herein by reference in its entirety.

[0002] This application relates to optical modulation devices. Background Technology

[0003] Optical modulation devices, which contain a light modulation layer such as a liquid crystal compound positioned between two substrates, are used in a wide variety of applications.

[0004] To ensure that the optical modulation device exhibits performance suitable for its intended use, it is important to control the orientation state of the liquid crystal compound between the substrates according to the purpose. In the case where the optical modulation layer is a liquid crystal layer, in order to control the orientation (especially the initial orientation) of the liquid crystal compound, the device using the liquid crystal compound forms an alignment film on the two substrate surfaces facing each other.

[0005] It is known that an optical device is configured by encapsulating a light modulation device with an encapsulant or the like, and pressure is applied to the optical device during the encapsulation process (e.g., Patent Document 1).

[0006] Therefore, in most cases, pressure is applied to the optical modulation device during the packaging process. This leads to the problem that the optical characteristics of the optical modulation device may change due to the applied pressure, resulting in characteristics different from the design, or the positions of the substrates positioned opposite each other may shift due to the pressure, thus creating optical defects.

[0007] [Existing Technical Documents]

[0008] [Patent Literature]

[0009] (Patent Document 1) Korean Patent Publication No. 2018-0119517 Summary of the Invention

[0010] Technical issues

[0011] This application provides an optical modulation device, an optical device, or a method for manufacturing the same. The purpose of this application is to provide an optical modulation device, an optical device, or a method for manufacturing the same that can stably maintain designed optical properties even after a packaging process in which pressure is applied, such as an autoclave process. This application also aims to provide an optical modulation device, an optical device including the same, or a method for manufacturing the same that can stably maintain the orientation state of the optical modulation layer while effectively ensuring the adhesion between the upper and lower substrates.

[0012] Technical solution

[0013] In this specification, the terms "perpendicular, parallel, orthogonal, or horizontal" that define angles and angle values ​​mean "substantially perpendicular, parallel, orthogonal, or horizontal" and a basic angle value within a range that does not impair the desired effect. Perpendicular, parallel, orthogonal, or horizontal, and the numerical range, include tolerances such as manufacturing errors or deviations (variations). For example, the above may each include an error within approximately ±10 degrees, approximately ±9 degrees, approximately ±8 degrees, approximately ±7 degrees, approximately ±6 degrees, approximately ±5 degrees, approximately ±4 degrees, approximately ±3 degrees, approximately ±2 degrees, approximately ±1 degree, approximately ±0.8 degrees, approximately ±0.6 degrees, or approximately ±0.4 degrees.

[0014] In this specification, when the measurement temperature affects the relevant physical properties, the physical properties are those measured at room temperature, unless otherwise stated. The term room temperature means temperature under conditions of no particular heating or cooling, and can refer to a temperature in the range of about 10°C to 30°C, for example, about 15°C or higher, 18°C ​​or higher, 20°C or higher, or about 23°C or higher and about 27°C or lower. Unless otherwise stated, the unit of temperature mentioned herein is °C.

[0015] Unless otherwise stated, the terms phase difference, refractive index, and refractive index anisotropy used in this specification refer to the phase difference, refractive index, and refractive index anisotropy for light with a wavelength of approximately 550 nm.

[0016] Unless otherwise stated, the angles formed by any two directions mentioned herein can be acute angles ranging from acute to obtuse angles formed by those two directions, or they can be small angles among those measured in the clockwise and counterclockwise directions. Therefore, unless otherwise stated, the angles mentioned herein are positive. However, if necessary, to indicate the direction of measurement between angles measured in the clockwise or counterclockwise direction, angles measured in the clockwise direction may be represented as positive numbers, and angles measured in the counterclockwise direction may be represented as negative numbers.

[0017] This application relates to an optical modulation device. The term optical modulation device can mean a device capable of switching between at least two or more different light states. Here, different light states can mean states with different transmittance, reflectance, color, and / or haze.

[0018] Examples of states that an optical modulation device can achieve include, but are not limited to, a transparent mode state, a black mode state, a high-reflectivity mode state, a low-reflectivity mode state, and / or a color mode state indicating a specific color.

[0019] In one instance, the optical modulation device can be a device capable of switching between at least a transparent mode state and a black mode state.

[0020] The transmittance of the optical modulation device in transparent mode can be at least 10% or greater, 15% or greater, 20% or greater, 25% or greater, 30% or greater, 35% or greater, 40% or greater, 45% or greater, 50% or greater, 55% or greater, 60% or greater, 65% or greater, 70% or greater, 75% or greater, or 80% or greater. In another example, the transmittance in transparent mode can also be around 100% or less, 95% or less, 90% or less, or around 85% or less. However, there is no particular upper limit, as higher transmittance in transparent mode is more advantageous.

[0021] The transmittance of the optical modulation device in black mode can be 60% or less, 55% or less, 50% or less, 45% or less, 40% or less, 35% or less, 30% or less, 25% or less, 20% or less, 15% or less, 10% or less, or 5% or less. In another example, the transmittance in black mode can also be approximately 0% or more, 5% or more, 10% or more, 15% or more, 20% or more, or around 25% or more. However, there is no particular limitation on the lower limit of the transmittance in black mode, as lower transmittance in black mode is more advantageous.

[0022] Transmittance can be, for example, linear light transmittance. Linear light transmittance is the percentage of light transmitted in the same direction as the incident direction to the light incident on the device. For example, if the device is in the form of a film or sheet, the percentage of light incident in a direction parallel to the normal to the surface of the film or sheet that passes through the device in a direction parallel to the normal can be defined as transmittance.

[0023] Transmittance can be individually defined as the transmittance to any wavelength in the visible light region, such as any wavelength in the range of about 400 nm to 700 nm or about 380 nm to 780 nm, or the transmittance over the entire visible light region, the maximum or minimum transmittance over the entire visible light region, or the average transmittance over the visible light region.

[0024] In one example, the optical modulation device of this application can be designed to switch between one state selected from a transparent mode state and a black mode state and another state. If needed, a third or more different states in addition to the states mentioned above can also be implemented.

[0025] The switching of the optical modulation device can be controlled based on whether an external signal, such as a voltage signal, is applied. For example, in the absence of an external signal, such as a voltage, the optical modulation device can remain in any of the aforementioned states, and then switch to another state when a voltage is applied. By changing the intensity, frequency, and / or shape of the applied voltage, the mode state can be changed, or a third different mode state can be achieved.

[0026] The optical modulation device of this application may include two substrates arranged opposite each other as basic units and an optical modulation film layer positioned between the substrates. Figure 1 This diagram illustrates an example of an optical modulation film. As shown, the optical modulation film includes a first substrate 100 and a second substrate 200 disposed opposite to each other. The first substrate and the second substrate may have a first surface and a second surface. Here, the first surface may be a main surface of the substrate, and the second surface may refer to the main surface opposite to the first surface.

[0027] As shown in the figure, a functional layer may be formed on one surface (e.g., the first surface) of the first substrate 100, and a liquid crystal alignment film 2001 may be formed on one surface (e.g., the first surface) of the second substrate 200. Here, the functional layer may also be a liquid crystal alignment film; in other examples, it may be an adhesive layer or a pressure-sensitive adhesive layer, as described below. A light modulation layer 600 is positioned between the opposing first substrate 100 and second substrate 200. When the light modulation layer is a liquid crystal layer, a liquid crystal alignment film is typically formed on both surfaces of the first substrate 100 and the second substrate 200. However, by forming a pressure-sensitive adhesive layer or an adhesive layer on the first substrate 100 instead of the liquid crystal alignment film, and forming the liquid crystal alignment film only on the second substrate 200, an alignment state of the liquid crystal compound that is very useful in specific applications (e.g., smart windows or eye-wearing devices) can be obtained. In this case, the liquid crystal alignment film may not be formed on the first substrate. Furthermore, although not shown in the figure, in either the first substrate or the second substrate of the light modulation film layer, there is a spacer for maintaining the gap (cell gap) between the first substrate and the second substrate. However, when the functional layer on the first substrate 100 is a pressure-sensitive adhesive layer or adhesive layer 1001, the pressure-sensitive adhesive layer or adhesive layer 1001 is attached to the spacer, thereby greatly improving the bonding force between the first substrate and the second substrate.

[0028] As the substrate, known substrate materials can be used without particular limitation. For example, inorganic substrates (such as glass substrates, crystalline silicon or amorphous silicon substrates, or quartz substrates) or plastic substrates can be used. As plastic substrates, TAC (triacetyl cellulose) substrates; COP (cyclic olefin copolymer) substrates, such as norbornene derivative substrates; PMMA (poly(methyl methacrylate)) substrates; PC (polycarbonate) substrates; PE (polyethylene) substrates; PP (polypropylene) substrates; PVA (polyvinyl alcohol) substrates; DAC (diacetyl cellulose) substrates; Pac (polyacrylate) substrates; PES (polyethersulfone) substrates; PEEK (polyether ether ketone) substrates; PPS (polyphenyl sulfone), PEI (polyetherimide) substrates; PEN (polyethylene naphthalate) substrates; polyester substrates such as PET (polyethylene terephthalate) substrates; PI (polyimide) substrates; PSF (polysulfone) substrates; PAR (polyarylate) substrates or substrates containing amorphous fluoropolymers, etc., but not limited to these. There are no particular restrictions on the thickness of such a substrate; the thickness can be selected within an appropriate range.

[0029] In one instance, an optically anisotropic film can also be used as the substrate. Films with such optical anisotropy are generally also anisotropic in mechanical properties, and by utilizing such anisotropy, optical modulation devices with excellent durability and other properties can be provided.

[0030] In one example, the in-plane phase difference of the anisotropic film can be about 500 nm or greater. The in-plane phase difference is a value for light with a wavelength of 550 nm and is a physical quantity defined by the following Equation 2. In another example, the in-plane phase difference of the retardation film can be 600 nm or greater, 700 nm or greater, 800 nm or greater, 900 nm or greater, 1000 nm or greater, 1100 nm or greater, 1200 nm or greater, 1300 nm or greater, 1400 nm or greater, 1500 nm or greater, 2000 nm or greater, 2500 nm or greater, 3000 nm or greater, 3500 nm or greater, 4000 nm or greater, 4500 nm or greater, 5000 nm or greater, 5500 nm or greater, 6000 nm or greater, 6500 nm or greater, 7000 nm or greater, 7500 nm or greater, 8000 nm or greater, 8500 nm or greater, 9000 nm or greater, or 9500 nm or greater. Large, or it could be 100,000nm or smaller, 90,000nm or smaller, 80,000nm or smaller, 70,000nm or smaller, 60,000nm or smaller, 50,000nm or smaller, 40,000nm or smaller, 30,000nm or smaller, 20,000nm or smaller, 15,000nm or smaller, 14,000nm or smaller, 13,000nm or smaller, 12,000nm or smaller, 10,000nm or smaller, 9,500nm or smaller, 9,000nm or smaller, 8,500nm or smaller, 8,000nm or smaller, 7,500nm or smaller, 7,000nm or smaller, 6,500nm or smaller, 6,000nm or smaller, 5,500nm or smaller, 5,000nm or smaller, or around 4,500nm or smaller.

[0031] In this application, there is no particular limitation on the specific type of film applicable to the substrate, as long as it exhibits an in-plane phase difference within the aforementioned range. For example, anisotropic polymer films that impart optical anisotropy through stretching can be used. Polymer films can be exemplified by: for example, polyolefin films, such as polyethylene films or polypropylene films; cyclic olefin polymer (COP) films, such as polynorbornene films; polyvinyl chloride films; polyacrylonitrile films; polysulfone films; polyacrylate films; PVA (poly(vinyl alcohol)) films or cellulose ester-based polymer films, such as TAC (triacetyl cellulose) films; polyester films or polycarbonate films; or copolymer films of two or more monomers forming the polymer; and so on.

[0032] In one example, polyester films, such as PET (polyethylene terephthalate) films, can be used as the film. That is, films exhibiting in-plane phase differences within the aforementioned range are known in the industry, and in the case of polymer films, such films exhibit asymmetry even in mechanical properties and large optical anisotropy during manufacturing processes, such as stretching. A representative example of such retardation films known in the industry is stretched polyester film, such as stretched PET (polyethylene terephthalate) film.

[0033] Therefore, in one instance, a polyester film, such as a PET film, can be used as the film, but the types of films suitable as the substrate in this application are not limited to this.

[0034] Furthermore, the in-plane phase difference is a physical quantity according to the following Equation 2.

[0035] [Equation 2]

[0036] Rin = d × (nx - ny)

[0037] In Equation 2, Rin represents the in-plane phase difference, nx represents the refractive index of the film along the slow axis, ny represents the refractive index of the film along the fast axis, and d represents the thickness of the film. Here, the meanings of the slow axis and fast axis are known in the industry.

[0038] Furthermore, when anisotropic films are applied to both a first substrate and a second substrate simultaneously, the substrates can be configured such that their slow axes are parallel or perpendicular to each other.

[0039] The optical modulation layer existing between the substrates is a functional layer that can change its transmittance, reflectance, haze, and / or color, either alone or in combination with other components, depending on whether an external signal is applied. In this paper, such an optical modulation layer can be referred to as an active optical modulation layer.

[0040] In this specification, "external signal" can refer to external factors, such as electrical signals like voltage, which can affect the behavior of the light modulation material (e.g., liquid crystal compound) contained in the light modulation layer (e.g., liquid crystal layer). Therefore, the state without any external signal can mean the state where no electrical signal is applied from the outside.

[0041] In this application, there are no particular limitations on the type of light modulation layer, as long as it has the above-mentioned functions, and known light modulation layers can be used. The light modulation layer can be, for example, a liquid crystal layer, an electrochromic material layer, a photochromic material layer, an electrophoretic material layer, or a dispersed particle alignment layer.

[0042] In one example, a liquid crystal layer can be used as a light modulation layer. A liquid crystal layer is a layer containing a liquid crystal compound. In this specification, the term "liquid crystal layer" encompasses all layers containing liquid crystal compounds, such as, as described below, a so-called host-guest layer containing a liquid crystal compound (liquid crystal host) and a dichroic dye, or a layer containing other additives such as chiral dopants and a liquid crystal compound, which is also a type of liquid crystal layer defined in this specification. The liquid crystal layer can be a light modulation film layer, and therefore a liquid crystal compound can be present in the liquid crystal layer such that the orientation direction changes depending on whether an external signal is applied. Any type of liquid crystal compound can be used as the liquid crystal compound, as long as the orientation direction can be changed by applying an external signal. For example, smectic, nematic, or cholesteric liquid crystal compounds can be used as the liquid crystal compound. Furthermore, the liquid crystal compound can be, for example, a compound that does not have polymerizable or crosslinkable groups such that the orientation direction can be changed by applying an external signal.

[0043] The liquid crystal layer may contain a liquid crystal compound with positive or negative dielectric anisotropy. The absolute value of the dielectric anisotropy of the liquid crystal can be appropriately selected in consideration of the purposes of this application. The term "dielectric anisotropy (Δε)" may refer to the difference (ε / / -ε⊥) between the horizontal dielectric constant (ε / / ) and the vertical dielectric constant (ε⊥) of the liquid crystal. In this specification, the term horizontal dielectric constant (ε / / ) refers to the dielectric constant measured along the direction of the electric field when a voltage is applied such that the direction of the liquid crystal's pointer is substantially horizontal to the direction of the electric field of the applied voltage, and the term vertical dielectric constant (ε⊥) refers to the dielectric constant measured along the direction of the electric field when a voltage is applied such that the direction of the liquid crystal's pointer is substantially perpendicular to the direction of the electric field of the applied voltage.

[0044] The driving modes of the liquid crystal layer can be exemplified by, for example, DS (Dynamic Scattering) mode, ECB (Electrically Controlled Birefringence) mode, IPS (In-Plane Switching) mode, FFS (Fringe Field Switching) mode, OCB (Optically Compensated Bending) mode, VA (Vertical Alignment) mode, MVA (Multi-Domain Vertical Alignment) mode, PVA (Patterned Vertical Alignment) mode, HAN (Hybrid Alignment Nematic) mode, TN (Twisted Nematic) mode, STN (Super Twisted Nematic) mode, or R-TN (Reverse Twisted Nematic) mode.

[0045] The liquid crystal layer of this application can be designed (formed) to achieve at least the twisted orientation described above. Twisted orientation refers to the state in which the liquid crystal compounds in the liquid crystal layer are oriented in a twisted manner based on an imaginary helical axis, and this twisted orientation can be achieved in a state in which the liquid crystal compounds of the liquid crystal layer are horizontally oriented, vertically oriented, tilted oriented, or ejected oriented. Furthermore, the twisted orientation can be achieved in the initial state of the liquid crystal layer, or it can be achieved when an external signal is applied. Here, the initial state means the state in which no external signal capable of controlling the orientation of the liquid crystal compounds is applied to the liquid crystal layer.

[0046] In one example, the liquid crystal layer can be a light modulation layer, initially in a vertically aligned state, and twistedly aligned when an external signal (such as an electrical signal like voltage) is applied.

[0047] The light modulation layer of the liquid crystal layer mainly contains liquid crystal compounds, and if necessary, the light modulation layer of the liquid crystal layer may also contain other components.

[0048] For example, the liquid crystal layer used as a light modulation layer can also contain so-called chiral dopants and liquid crystal compounds. Such chiral dopants can induce the orientation of the helical structure in the liquid crystal compound, i.e., a twisted orientation.

[0049] Chiral dopants that can be included in the light modulation layer can be used without particular restrictions, as long as they can induce the desired rotation (twisting) without degrading the liquid crystal properties, such as nematic regularity. The chiral dopant used to induce the rotation of the liquid crystal molecules needs to include at least chirality in its molecular structure. Chiral dopants can be exemplified by, for example, compounds having one or two or more asymmetric carbons, compounds having asymmetric points on heteroatoms (e.g., chiral amines or chiral sulfoxides), or compounds having axially asymmetric and optically active sites (e.g., cumulative polyenes or binatol). Chiral dopants can be, for example, low molecular weight compounds with a molecular weight of 1,500 or less. Commercially available chiral nematic liquid crystals can be used as chiral dopants, such as the chiral doped liquid crystal S811 available from Merck Co., Ltd., or BASF's LC756.

[0050] There is no particular limitation on the ratio of chiral dopants, but they can be added such that the ratio (t, inter-cell gap) of the thickness of the light modulation layer to the pitch (t-orientation pitch) (p) of the helical structure of the liquid crystal compound generated by the addition of chiral dopants (t / p) can satisfy the K value described below.

[0051] The pitch (p) of a so-called twisted-oriented optical modulation layer (liquid crystal layer) employing chiral dopants can be measured using a wedge cell measurement method, and this pitch (p) can be measured using the method described in D. Podolskyy et al.'s "Simple method for accurate measurement of the cholesteric pitch using a 'stripe-wedge Grandjean-Cano cell'" (Liquid Crystals, Vol. 35, No. 7, July 8, 2008, 789-791). Furthermore, the chiral dopant content (wt%) is calculated using the equation 100 / (HTP (helical twisting power) × pitch (nm)), and the chiral dopant content can be selected at an appropriate ratio considering the desired pitch (p).

[0052] In one instance, the optical modulation layer can be designed (formed) such that the K value of Equation 1 below is in the range of 0.15 to 0.4.

[0053] [Equation 1]

[0054] K = Δn × p / t

[0055] In Equation 1, Δn is the refractive index anisotropy of the liquid crystal layer, p is the pitch of the twisted orientation, and t is the thickness of the liquid crystal layer.

[0056] The thickness of the liquid crystal layer (which is t in Equation 1 above) is what the industry calls the thickness of the intercellular gap. In Equation 1, the refractive index anisotropy has no unit, and the units of the pitch (p) and thickness (t) of the liquid crystal layer are the same, therefore the unit of the K value does not exist.

[0057] The refractive index anisotropy associated with Equation 1 can be measured in the manner described in the examples.

[0058] By setting the K value in Equation 1 to the range of 0.15 to 0.4, an optical modulation device can be provided that can stably maintain the optical properties of the design even after a packaging process in which pressure is applied (e.g., an autoclave process).

[0059] There are no particular restrictions on the methods for designing the light modulation layer so that the K value falls within the above range. For example, considering the anisotropy of the refractive index (Δn) and the thickness (t, intercellular gap) of the liquid crystal layer, the pitch (p) can be achieved by adjusting the ratio of chiral dopants, which can exhibit the desired K value.

[0060] In another instance, the value of K can be 0.16 or greater, 0.17 or greater, 0.18 or greater, 0.19 or greater, 0.2 or greater, or greater than 0.2, or it can be 0.39 or less, 0.38 or less, 0.37 or less, 0.36 or less, 0.35 or less, 0.34 or less, 0.33 or less, 0.32 or less, 0.31 or less, 0.3 or less, or less than 0.3.

[0061] In Equation 1, the ranges of the refractive index anisotropy (Δn), the pitch (p), and the thickness (t) of the liquid crystal layer can be selected from the ranges that can represent the K value.

[0062] For example, the refractive index anisotropy (Δn) of the liquid crystal layer can be in the range of 0.01 to 0.5. In another example, the refractive index anisotropy can be 0.02 or greater, 0.03 or greater, 0.04 or greater, 0.05 or greater, 0.06 or greater, 0.07 or greater, 0.08 or greater, or 0.085 or greater, or it can be 0.45 or less, 0.4 or less, 0.35 or less, 0.3 or less, 0.25 or less, 0.2 or less, 0.15 or less, or around 0.1 or less.

[0063] Furthermore, the pitch (p) of the twist orientation can range from 1 μm to 100 μm. In another example, the pitch can be 2 μm or greater, 3 μm or greater, 4 μm or greater, 5 μm or greater, 6 μm or greater, 7 μm or greater, 8 μm or greater, 9 μm or greater, or 9.5 μm or greater, or it can be 95 μm or less, 90 μm or less, 85 μm or less, 80 μm or less, 75 μm or less, 70 μm or less, 65 μm or less, 60 μm or less, 55 μm or less, 50 μm or less, 45 μm or less, 40 μm or less, 35 μm or less, 30 μm or less, or around 25 μm or less.

[0064] Furthermore, the thickness (t, cell gap) of the liquid crystal layer can range from 0.5 μm to 50 μm. In another example, the thickness (t, cell gap) can be 1 μm or greater, 1.5 μm or greater, 2 μm or greater, 2.5 μm or greater, 3 μm or greater, or 3.5 μm or greater, or it can also be 48 μm or less, 46 μm or less, 44 μm or less, 42 μm or less, 30 μm or less, 38 μm or less, 36 μm or less, 34 μm or less, 32 μm or less, 30 μm or less, 28 μm or less, 26 μm or less, 24 μm or less, 22 μm or less, 20 μm or less, 18 μm or less, 16 μm or less, 14 μm or less, 12 μm or less, or approximately 10 μm or less.

[0065] Furthermore, the ratio (t / p) of the thickness (t, cell gap) of the light modulation layer (liquid crystal layer) to the pitch (p) of the twisted orientation can be less than 1. In another example, the ratio (t / p) can be 0.95 or less, 0.9 or less, 0.85 or less, 0.8 or less, 0.75 or less, 0.7 or less, 0.65 or less, 0.6 or less, 0.55 or less, 0.5 or less, 0.45 or less, 0.4 or less, or 0.35 or less, or it can be approximately 0.1 or greater, 0.15 or greater, 0.2 or greater, 0.25 or greater, 0.3 or greater, 0.35 or greater, or 0.4 or greater.

[0066] This design provides an optical modulation device that more effectively achieves the objectives of this application.

[0067] Other necessary additional components (such as dichroic dyes) may also be included in the light modulation layer (liquid crystal layer).

[0068] There are no particular limitations on the type of liquid crystal alignment film that can be formed on the first surface of the first substrate and / or the second substrate. Known vertical or horizontal alignment films or other alignment films can be applied as alignment films, taking into account the desired initial orientation. As for the type of alignment film, contact alignment films (e.g., rubbing alignment films) or non-contact alignment films (e.g., photoalignment films) can be applied. In one example, a vertical alignment film can be used as the alignment film. For example, the combination of a vertical alignment film and a pressure-sensitive adhesive layer or adhesive layer, as described below, can induce an alignment state of the liquid crystal compound suitable for various applications.

[0069] When an adhesive layer or pressure-sensitive adhesive layer is formed on the first surface of the first substrate in the light modulation film layer, there are no particular limitations on the type of adhesive layer or pressure-sensitive adhesive layer. For example, various types of pressure-sensitive adhesives or binders, known in the industry as so-called OCA (Optically Transparent Adhesive) or OCR (Optically Transparent Resin), can be bonded to the liquid crystal alignment film to induce a suitable orientation of the liquid crystal compound. As pressure-sensitive adhesives or binders, for example, acrylic, silicone-based, epoxy-based, or urethane-based pressure-sensitive adhesives or binders can be applied.

[0070] Silicone-based pressure-sensitive adhesives or binders can be cited as examples of suitable pressure-sensitive adhesives or binders. The specific surface properties of silicone-based pressure-sensitive adhesives or binders can combine with liquid crystal alignment films (especially vertical alignment films) to induce an orientation state of the liquid crystal compound suitable for the purpose.

[0071] As a silicone-based pressure-sensitive adhesive or binder, a cured product of a curable silicone adhesive or pressure-sensitive adhesive composition (hereinafter, may be simply referred to as a curable silicone composition) can be used. There are no particular limitations on the type of curable silicone composition; for example, a thermosetting silicone composition or a UV-curable silicone composition can be used.

[0072] In one example, the curable organosilicon composition is an addition-curable organosilicon composition, which may include (1) an organopolysiloxane containing two or more alkenyl groups in its molecule and (2) an organopolysiloxane containing two or more hydrogen atoms bonded to silicon in its molecule. Such organosilicon compounds can, for example, form cured products through an addition reaction in the presence of a catalyst such as a platinum catalyst.

[0073] (1) An organopolysiloxane, as a major component constituting an organosilicon cured product, contains at least two alkenyl groups in one molecule. Specific examples of alkenyl groups include vinyl, allyl, butenyl, pentenyl, hexenyl, or heptenyl, etc., and vinyl is generally used, but not limited thereto. In (1) organopolysiloxanes, the bonding position of the alkenyl groups as described above is not particularly limited. For example, the alkenyl group can be bonded to the end of the molecular chain and / or to the side chain of the molecular chain. Furthermore, in (1) organopolysiloxanes, the types of substituents that can be included in addition to the alkenyl groups described above can include alkyl groups, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, or heptyl; aryl groups, such as phenyl, tolyl, xylyl, or naphthyl; aralkyl groups, such as benzyl or phenethyl; halogen-substituted alkyl groups, such as chloromethyl, 3-chloropropyl, or 3,3,3-trifluoropropyl; etc., and methyl or phenyl is generally used, but not limited thereto.

[0074] (1) There are no particular restrictions on the molecular structure of organopolysiloxanes, and they can have any shape, such as linear, branched, cyclic, network, or partially branched linear. Among such molecular structures, those with linear molecular structures are usually used, but are not limited to this.

[0075] (1) More specific examples of organopolysiloxanes may include: dimethylsiloxane-methylvinylsiloxane copolymers with trimethylsiloxane groups at both ends of the molecular chain; methylvinylpolysiloxanes with trimethylsiloxane groups at both ends of the molecular chain; dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymers with trimethylsiloxane groups at both ends of the molecular chain; dimethylpolysiloxanes with dimethylvinylsiloxane groups at both ends of the molecular chain; methylvinylpolysiloxanes with dimethylvinylsiloxane groups at both ends of the molecular chain; dimethylsiloxane-methylvinylsiloxane copolymers with dimethylvinylsiloxane groups at both ends of the molecular chain; dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymers with dimethylvinylsiloxane groups at both ends of the molecular chain; and copolymers containing R 1 2SiO 2 / 2 The siloxane unit represented by R and the siloxane unit represented by R 1 2R 2 SiO 1 / 2 The siloxane unit represented and the siloxane unit composed of SiO 4 / 2 The organopolysiloxane copolymer representing the siloxane unit, comprising R 1 2R 2 SiO 1 / 2 The siloxane unit represented and the siloxane unit composed of SiO 4 / 2 The organopolysiloxane copolymer representing the siloxane unit, comprising R 1 R 2 SiO 2 / 2 The siloxane unit represented by R and the siloxane unit represented by R 1 SiO 3 / 2 The siloxane unit represented by R or made of 2 SiO 3 / 2 The term refers to organopolysiloxane copolymers containing siloxane units, and mixtures of two or more of the aforementioned, but is not limited thereto. Here, R... 1 This refers to a hydrocarbon group other than an alkenyl group, specifically alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, or heptyl; aryl groups such as phenyl, tolyl, xylyl, or naphthyl; aralkyl groups such as benzyl or phenethyl; halogen-substituted alkyl groups such as chloromethyl, 3-chloropropyl, or 3,3,3-trifluoropropyl; and so on. Furthermore, R... 2 It is an alkenyl group, specifically, it can be vinyl, allyl, butenyl, pentenyl, hexenyl or heptenyl, etc.

[0076] In an addition-curable organosilicon composition, (2) the organopolysiloxane can be used to crosslink (1) the organopolysiloxane. In (2) the organopolysiloxane, the bonding position of the hydrogen atoms is not particularly limited; they can, for example, be bonded to the ends and / or side chains of the molecular chain. Furthermore, in (2) the organopolysiloxane, there is no particular limitation on the types of substituents that can be included in addition to the hydrogen atoms bonded to silicon. Substituents can include, for example, alkyl, aryl, aralkyl, or halogen-substituted alkyl groups as mentioned in (1) the organopolysiloxane, wherein methyl or phenyl is commonly used, but not limited to these.

[0077] (2) There are no particular restrictions on the molecular structure of organopolysiloxanes, and they can have any shape, such as linear, branched, cyclic, network, or partially branched linear. Among such molecular structures, those with linear molecular structures are usually used, but are not limited to this.

[0078] (2) More specific examples of organopolysiloxanes may include: methylhydropolysiloxanes end-capped with trimethylsiloxane groups at both ends of the molecular chain; dimethylsiloxane-methylhydropolymers end-capped with trimethylsiloxane groups at both ends of the molecular chain; dimethylsiloxane-methylhydrosiloxane-methylphenylsiloxane copolymers end-capped with trimethylsiloxane groups at both ends of the molecular chain; dimethylpolysiloxanes end-capped with dimethylhydrosiloxane groups at both ends of the molecular chain; dimethylsiloxane-methylphenylsiloxane copolymers end-capped with dimethylhydrosiloxane groups at both ends of the molecular chain; and methylphenylpolysiloxanes end-capped with dimethylhydrosiloxane groups at both ends of the molecular chain, comprising R 1 3SiO 1 / 2 The siloxane unit represented by R 1 2HSiO 1 / 2 The siloxane unit represented and the siloxane unit composed of SiO 4 / 2 The organopolysiloxane copolymer representing the siloxane unit comprises R 1 2HSiO 1 / 2 The siloxane unit represented and the siloxane unit composed of SiO 4 / 2 The organopolysiloxane copolymer representing the siloxane unit comprises R 1 HSiO 2 / 2 The siloxane unit represented by R and the siloxane unit represented by R 1 SiO 3 / 2 The siloxane unit represented is or is composed of HSiO 3 / 2 The organopolysiloxane copolymer representing the siloxane unit, and mixtures of two or more of the foregoing, but not limited thereto. Here, R 1It can be a hydrocarbon group other than an alkenyl group. Specifically, it can 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; a halogen-substituted alkyl group, such as chloromethyl, 3-chloropropyl or 3,3,3-trifluoropropyl; and so on.

[0079] (2) There is no particular limitation on the content of the organopolysiloxane, as long as it is contained to a degree that allows for proper curing. For example, (2) the organopolysiloxane may be contained in an amount of 0.5 to 10 silicon-bonded hydrogen atoms per alkenyl group contained in (1) the organopolysiloxane as described above. Within such a range, sufficient curing can be achieved and heat resistance can be ensured.

[0080] Addition-curable silicone compositions may also contain platinum or platinum compounds as catalysts for curing. There are no particular limitations on the specific type of platinum or platinum compound. The catalyst ratio can also be adjusted to a level suitable for proper curing.

[0081] In addition, the addition-curable silicone composition may also contain appropriate additives in suitable proportions as needed from the viewpoint of improving storage stability, handling properties and processability.

[0082] In another example, the silicone composition, as a condensable curable silicone composition, may comprise, for example, (a) an alkoxy-containing siloxane polymer; and (b) a hydroxyl-containing siloxane polymer.

[0083] (a) The siloxane polymer can be, for example, a compound represented by Formula 1 below.

[0084] [Formula 1]

[0085] R 1 a R 2 b SiO c (OR 3 ) d

[0086] In Equation 1, R 1 and R 2 Each independently represents a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, R 3 Represents an alkyl group, wherein when a plurality of R are present... 1 R 2 and R 3 When, they can be the same or different from each other, and a and b can each independently represent a number that is 0 or greater than and less than 1, a+b represents a number that is greater than 0 and less than 2, c represents a number that is greater than 0 and less than 2, d represents a number that is greater than 0 and less than 4, and a+b+c×2+d equals 4.

[0087] In the definition of Formula 1, the monovalent hydrocarbon group can be, for example, an alkyl, phenyl, benzyl, or tolyl group having 1 to 8 carbon atoms, wherein the alkyl group having 1 to 8 carbon atoms can be methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, heptyl, or octyl, etc. Furthermore, in the definition of Formula 1, the monovalent hydrocarbon group can be substituted with known substituents such as halogen, amino, mercapto, isocyanate, glycidyl, glycidoxy, or urea.

[0088] Under the constraints of Equation 1, R 3 Examples of alkyl groups may include methyl, ethyl, propyl, isopropyl, or butyl, etc. Among these alkyl groups, methyl or ethyl are commonly used, but are not limited to these.

[0089] In the polymer of Formula 1, branched or tertiary crosslinked siloxane polymers can be used. Furthermore, in this (a) siloxane polymer, hydroxyl groups may remain to a extent that does not impair the purpose, specifically to a extent that does not inhibit the de-alcoholization reaction.

[0090] (a) Siloxane polymers can be produced, for example, by hydrolysis and condensation of polyfunctional alkoxysilanes or polyfunctional chlorosilanes. Those skilled in the art can readily select suitable polyfunctional alkoxysilanes or chlorosilanes according to the desired (a) siloxane polymer, and can also readily control the conditions of the hydrolysis and condensation reactions using them. Furthermore, in the production of (a) siloxane polymers, suitable monofunctional alkoxysilanes can also be used in combination, depending on the purpose.

[0091] As (a) a siloxane polymer, commercially available organosiloxane polymers such as Shin-Etsu Silicone's X40-9220 or X40-9225, or GE Toray Silicone's XR31-B1410, XR31-B0270, or XR31-B2733 can be used.

[0092] (b) A hydroxyl-containing siloxane polymer may be used as a component in a condensable and curable organosilicon composition, for example, a compound represented by Formula 2 below.

[0093] [Equation 2]

[0094]

[0095] In Equation 2, R4 and R5 each independently represent a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, wherein when there are multiple R4s and R5s, they may be the same or different from each other, and n represents an integer from 5 to 2,000.

[0096] In the definition of Formula 2, the specific type of monovalent hydrocarbon group may include, for example, the same hydrocarbon group as in Formula 1 above.

[0097] (b) Siloxane polymers can be produced, for example, by hydrolysis and condensation of dialkoxysilanes and / or dichlorosilanes. Those skilled in the art can readily select suitable dialkoxysilanes or dichlorosilanes according to the desired (b) siloxane polymer, and can also readily control the conditions of the hydrolysis and condensation reactions using them. As the (b) siloxane polymers described above, commercially available bifunctional organosiloxane polymers can be used, such as GE Toray Silicone's XC96-723, YF-3800, or YF-3804, etc.

[0098] The above-described addition-curing or condensation-curing silicone compositions are examples of materials used to form the silicone pressure-sensitive adhesives or binders used in this application. In essence, all silicone pressure-sensitive adhesives or binders known in the industry as OCA or OCR, etc., can be used in this application.

[0099] There are no particular limitations on the type of pressure-sensitive adhesive or binder or curable composition forming therefrom, which may be appropriately selected according to the intended use. For example, solid, semi-solid, or liquid pressure-sensitive adhesives or binders or curable compositions may be used. Solid or semi-solid pressure-sensitive adhesives or binders or curable compositions can cure before the bonded objects are bonded. Liquid pressure-sensitive adhesives or binders or curable compositions are referred to as so-called optically clear resins (OCR), which can cure after the bonded objects are bonded. According to one example, as pressure-sensitive adhesives or binders or curable compositions, so-called polydimethylsiloxane-based pressure-sensitive adhesives or binders or curable compositions, or polymethylvinylsiloxane-based pressure-sensitive adhesives or binders or curable compositions, or alkoxysilicone-based pressure-sensitive adhesives or binders or curable compositions may be used, but are not limited thereto.

[0100] There are no particular limitations on the thickness of the pressure-sensitive adhesive layer or adhesive layer; it can be selected within an appropriate range to ensure the desired adhesion or cohesion. The thickness can range from about 1 μm to 50 μm. In another example, the thickness can be 2 μm or greater, 3 μm or greater, 4 μm or greater, 5 μm or greater, 6 μm or greater, 7 μm or greater, 8 μm or greater, 9 μm or greater, or 10 μm or greater, or it can also be 45 μm or less, 40 μm or less, 35 μm or less, 30 μm or less, 25 μm or less, 20 μm or less, 15 μm or less, or about 10 μm or less.

[0101] When such a pressure-sensitive adhesive layer or adhesive layer is formed on the first surface of the first substrate, it is not necessary to form a liquid crystal alignment film on the first substrate.

[0102] The initial orientation of the liquid crystal compound formed from the liquid crystal alignment film and / or the pressure-sensitive adhesive layer or adhesive layer, and the liquid crystal alignment film in the liquid crystal layer that serves as the light modulation layer, can be vertical, horizontal, tilted, or jet-sprayed. Furthermore, in the vertical, horizontal, tilted, or jet-sprayed orientation, the liquid crystal compound can be twisted or not twisted to exist in a twisted or cholesteric orientation. Initial orientation refers to the orientation in the state where no external signal is applied to the light modulation layer containing the liquid crystal compound.

[0103] The meanings of horizontal orientation, tilted orientation, vertical orientation, or jet orientation are known in the art. When the liquid crystal compound of the light modulation layer maintains a horizontal, tilted, vertical, or jet orientation in its initial state, it can change to other orientation states according to an external signal.

[0104] In one example, the initial orientation of the liquid crystal compound in the light modulation layer can be a vertical orientation or a similar orientation, and a twisted orientation can be achieved upon application of an external signal. Such an orientation is obtained by applying a vertical alignment film as the liquid crystal alignment film. This orientation is useful in elements that achieve a so-called R-TN (reverse twisted nematic) orientation.

[0105] The in-plane phase difference (based on a wavelength of 550 nm) of the optical modulation layer in a vertically oriented or similarly vertically oriented state can be, for example, about 30 nm or less, 25 nm or less, 20 nm or less, 15 nm or less, 10 nm or less, or 5 nm or less, or it can be 0 nm or more, or greater than 0 nm.

[0106] The in-plane phase difference is obtained according to Equation 2 above. In this case, nx, ny and d in Equation 2 are the refractive index of the slow axis, the refractive index of the fast axis and the thickness of the light modulation layer, respectively.

[0107] The optical modulation film layer may also include spacers for maintaining the distance between the first substrate and the second substrate. As spacers, spherical spacers, cylindrical spacers, or partition wall spacers, or combinations of two or more of these, can be used. In a suitable example, partition wall spacers can be used, particularly those in which the partition walls form at least one closed shape. Examples of closed shapes formed by partition wall spacers include hexagons (e.g., regular hexagons) or quadrilaterals (e.g., squares or rectangles). Partition wall spacers whose closed shapes are hexagons, especially regular hexagons, are also called so-called honeycomb-type spacers. When the shape of the spacers formed on the substrate is viewed from the normal direction of the substrate, as is known, such honeycomb or quadrilateral spacers refer to cases where the pattern formed by the spacers is honeycomb-type or quadrilateral-type. Honeycomb types are typically combinations of regular hexagons; in the case of quadrilateral types, squares, rectangles, or combinations of squares and rectangles, etc., may exist. Considering the adhesion between the first substrate and the second substrate, a spacer wall can be used as a spacer, but is not limited to this.

[0108] The spacing of the spacers can also be appropriately selected by considering factors such as desired adhesion or cell gap retention efficiency. For example, when applying spacers, the spacing can range from 50 μm to 2,000 μm. For instance, if the spacers are honeycomb type, the spacing is obtained by the spacing between opposite sides of the hexagons forming the honeycomb; in the case of quadrilaterals, the spacing is obtained by the length of the sides of the quadrilaterals. When the spacing between the opposite sides of the hexagons forming the honeycomb or the length of the sides of the quadrilaterals are not constant, their average value can be defined as the spacing.

[0109] When the partition walls form a closed figure, for example, the area of ​​the closed figure (i.e., the area of ​​a hexagon or quadrilateral) can be in the range of approximately 1 mm² to 200 mm². When multiple closed figures are formed by the partition walls and the closed figures have different areas, the area is the arithmetic mean.

[0110] The linewidth of the spacers, such as the width of each wall of the hexagons or quadrilaterals forming a honeycomb, can range, for example, from about 5 μm to 50 μm. In another example, the linewidth can be about 10 μm or more, or 15 μm or more, or it can be about 45 μm or less, 40 μm or less, 35 μm or less, 30 μm or less, 25 μm or less, or about 20 μm or less.

[0111] Within this range, the inter-unit spacing can be appropriately maintained, and the adhesion between substrates can also be maintained very well. For example, when a pressure-sensitive adhesive layer or adhesive layer is formed on the first substrate, its combination with the spacer can provide excellent adhesion between the substrates.

[0112] As a component for applying external signals to the optical modulation layer, electrode layers can be formed on each substrate of the optical modulation film layer. For example, the electrode layer may exist between a first surface in the first substrate and a functional layer (liquid crystal alignment film, pressure-sensitive adhesive, or adhesive layer). Figure 1 Between 100 and 1001 in the middle) and / or between the first surface in the second substrate and the liquid crystal alignment film ( Figure 1 (between 200 and 2001) (if a spacer is present, then between the spacer and the alignment film). In the case of a second substrate, an electrode layer is typically formed first on the first surface, and spacers and alignment films are sequentially formed on the electrode layer such that, when spacers are present, the electrode layer can be located between the first surface of the second substrate and the spacers and alignment films.

[0113] As the electrode layer, known transparent electrode layers can be used, such as so-called conductive polymer layers, conductive metal layers, conductive nanowire layers, or metal oxide layers such as ITO (indium tin oxide). Furthermore, various materials and methods for forming transparent electrode layers are known, and these materials and methods can be used without limitation.

[0114] The optical modulation device, while primarily comprising an optical modulation film layer, may include other additional structures as needed. That is, depending on the driving mode, even with only an optical modulation film layer, the aforementioned transparent mode, black mode, high-reflection mode, and / or low-reflection mode, as well as the switching between them, are possible. However, additional components may be included to facilitate the implementation or switching of these modes.

[0115] For example, the device may also include a polarizing layer (passive polarizing layer) disposed on one or both sides of the optical modulation film layer. In one example, the device further includes a polarizing layer disposed on a second surface of the first substrate or the second substrate. As an example of the above structure... Figure 2 yes Figure 1 In the structure where the polarizing layer 400 is only disposed on one side of the optical modulation film layer, Figure 3 yes Figure 1In this structure, the polarizing layer 400 is disposed on both sides of the light modulation film layer. Furthermore, when a spacer is used as the spacer and is quadrilateral (square or rectangular) in shape, the sides of the quadrilateral and the absorption axis of the polarizing layer are appropriately set to be substantially perpendicular or horizontal to each other. In one example, a small angle between the slow axis of the first or second substrate and the absorption axis of the polarizing layer can be in the range of 80 to 100 degrees.

[0116] The term "polarizing layer" can refer to an element that converts natural or unpolarized light into polarized light. In one instance, a polarizing layer can be a linear polarizing layer. A linear polarizing layer is defined as selectively transmitting linearly polarized light that vibrates in either direction and selectively absorbing or reflecting linearly polarized light that vibrates in a direction orthogonal to the vibration direction of the linearly polarized light. That is, a linear polarizing layer can have transmission axes and absorption axes or reflection axes that are orthogonal to each other in a planar direction.

[0117] The polarizing layer can be an absorptive polarizing layer or a reflective polarizing layer. As an absorptive polarizing layer, for example, a polarizing layer in which iodine is dyed onto a polymer stretched film (e.g., a PVA stretched film) can be used, or a host-guest polarizing layer in which liquid crystal polymerized in an oriented state is used as the host and dichroic dyes aligned along the orientation of the liquid crystal are used as guests, but it is not limited to these.

[0118] As a reflective polarizing layer, for example, a reflective polarizing layer known as a so-called DBEF (dual brightness enhancement film) can be used, or a reflective polarizing layer formed by coating a liquid crystal compound (such as LLC (lyotropic liquid crystal)), but is not limited to these.

[0119] like Figure 3 As shown, the optical modulation device can have a structure in which polarizing layers are disposed on both sides of the optical modulation film. In this case, the angle formed by the transmission axes of the polarizing layers disposed on both sides can be in the range of 85 degrees to 95 degrees, or approximately perpendicular.

[0120] In one instance, the optical device may also be configured to not include any polarizing layer. For example, the optical device may also be configured to not apply any polarizing layer after the dichroic dye, which is another component, is blended into the liquid crystal layer.

[0121] In addition to the above-mentioned structures, optical modulation devices may also include other necessary structures.

[0122] For example, an optical modulation device may also include an optically anisotropic film that satisfies the refractive index relationship of Equation 3 below. Such a film can also improve the performance of the device by optically compensating the substrate or the optical modulation layer.

[0123] [Formula 3]

[0124] nz <ny

[0125] In Equation 3, ny is the refractive index of the optical anisotropic film for a wavelength of 550 nm in the fast axis direction, and nz is the refractive index of the optical anisotropic film for a wavelength of 550 nm in the thickness direction.

[0126] An optically anisotropic film that satisfies the relationship in Equation 3 above is a film that exhibits the characteristics of a so-called negative C-plate.

[0127] The thickness direction phase difference of an optical anisotropic film can, for example, be in the range of -700 nm to -10 nm. The optical anisotropic film can also exist in an optical device as one layer or two or more layers. When the optical anisotropic film exists as one layer, the thickness direction phase difference is the phase difference of that single layer. When the optical anisotropic film exists as two or more layers, the thickness direction phase difference is the sum of the thickness direction phase differences of all the layers.

[0128] Furthermore, the phase difference in the thickness direction is a physical quantity determined by the following equation 4.

[0129] [Equation 4]

[0130] Rth = d × (nz - ny)

[0131] In Equation 4, Rth represents the phase difference along the thickness direction, nz represents the refractive index along the thickness direction of the film, ny represents the refractive index along the fast axis of the film, and d represents the thickness of the film. Here, the meanings of the thickness direction and the fast axis are known in the industry.

[0132] As an optically anisotropic film, it can be applied to known retardation films that satisfy Equation 3 above, and such films, for example, stretched polymer films or liquid crystal films, are widely known in the industry.

[0133] An optically anisotropic film can exist on a first substrate and / or a second substrate, and the optically anisotropic film can be formed, for example, on a first surface of the first substrate and / or the second substrate. In this case, the optically anisotropic film can exist between the first substrate and / or the second substrate and the light modulation layer; when a liquid crystal alignment film or a pressure-sensitive adhesive layer or an adhesive layer (such as a liquid crystal alignment film) is formed on the first surface, the optically anisotropic film can be formed between the first substrate and / or the second substrate and the liquid crystal alignment film, etc.; when an electrode layer is formed on the first surface, the optically anisotropic film can also be formed between the first substrate and / or the second substrate and the electrode layer.

[0134] If necessary, the optical modulation device may include other constructions in addition to the above-described constructions. For example, any other constructions required for driving or using the optical modulation device may be added, such as pressure-sensitive adhesive layers or adhesive layers for attaching other components, hard coating films, anti-reflective films, and / or NIR (near-infrared) cut-off layers, in addition to the pressure-sensitive adhesive layer or adhesive layer formed on the first surface of the first substrate.

[0135] There are no particular restrictions on the methods used to manufacture the optical modulation device, and the device can be manufactured by known methods, the difference being the application of the above-mentioned components as each part.

[0136] This application also relates to optical devices. Optical devices may have a structure in which an optical modulation device is encapsulated with an encapsulant.

[0137] Such an optical device may include: a first outer substrate and a second outer substrate disposed opposite to each other; and an optical modulation device encapsulated between the first outer substrate and the second outer substrate with an encapsulant. The first outer substrate and the second outer substrate are separate substrates, distinct from the substrates included in the optical modulation film layer, and are therefore referred to as outer substrates. Thus, the optical device may include at least four substrates, including the first and second substrates included in the optical modulation film layer, as well as the first and second outer substrates.

[0138] The designations "first" and "second" in the substrate name are convenient for distinguishing the substrates, and these designations do not specify the front-to-back or top-to-bottom relationship between the substrates or outer substrates. The optical modulation device can be encapsulated between two outer substrates. Such encapsulation can be accomplished using an encapsulant, which can be an adhesive film.

[0139] As the outer substrate, inorganic substrates or plastic substrates made of glass or the like can be used. Plastic substrates that can be used include TAC (triacetyl cellulose) membranes; COP (cyclic olefin copolymer) membranes, such as norbornene derivatives; acrylic membranes, such as PMMA (poly(methyl methacrylate)); PC (polycarbonate) membranes; PE (polyethylene) membranes; PP (polypropylene) membranes; PVA (polyvinyl alcohol) membranes; DAC (diacetyl cellulose) membranes; Pac (polyacrylate) membranes; PES (polyethersulfone) membranes; PEEK (polyether ether ketone) membranes; PPS (polyphenyl sulfone) membranes; PEI (polyetherimide) membranes; PEN (polyethylene naphthalate) membranes; PET (polyethylene terephthalate) membranes; PI (polyimide) membranes; PSF (polysulfone) membranes; PAR (polyarylate) membranes; or fluoropolymer membranes, etc., but are not limited to these. If necessary, a coating of gold, silver, or silicon compounds (such as silicon dioxide or silicon monoxide) or a coating such as an anti-reflective layer may also be present on the outer substrate.

[0140] There is no particular limitation on the thickness of the outer substrate, and it can be, for example, about 0.3 mm or more. In another example, the thickness can be about 0.5 mm or more, about 1 mm or more, about 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.

[0141] The outer substrate can be a flat substrate or a substrate with a curved surface shape. For example, both outer substrates can be flat substrates and have curved surface shapes at the same time, or one of them can be a flat substrate and the other can be a substrate with a curved surface shape.

[0142] Here, when both surfaces have curved shapes, the curvatures or radii of curvature can be the same or different.

[0143] The optical device may also include an encapsulant, such as an adhesive film, for encapsulating the optical modulation device within an outer substrate. Such an adhesive film may, for example, be present at least between the outer substrate and the optical modulation device. For instance, when the optical modulation device comprises both an optical modulation layer and a polarizing layer, the encapsulant (adhesive film) may be present at at least one location between the outer substrate and the optical modulation layer, between the optical modulation layer and the polarizing layer, and between the polarizing layer and the outer substrate. Furthermore, the encapsulant may be present on the sides of the optical modulation device (suitably all sides), such as the sides of the optical modulation layer and the polarizing layer (suitably all sides).

[0144] An adhesive film, acting as an encapsulant, can encapsulate the optical modulation device while bonding the outer substrate and at least one component of the optical modulation device to each other.

[0145] For example, the structure can be achieved through a high-pressure autoclave process, in which an outer substrate, an optical modulation device, and an encapsulant (adhesive film) are laminated according to the desired structure, and then pressed. In this application, even after such a pressurization process, the performance of the optical modulation device can be effectively maintained as designed.

[0146] As an encapsulant (adhesive film), known materials can be used without particular limitation. For example, suitable films can be selected from known thermoplastic polyurethane (TPU) adhesive films, TPS (thermoplastic starch), polyamide adhesive films, polyester adhesive films, EVA (ethylene vinyl acetate) adhesive films, polyolefin adhesive films such as polyethylene or polypropylene, or polyolefin elastomer films (POE films), etc.

[0147] The thickness of the encapsulant (adhesive film, etc.) is not particularly limited and can be, for example, in the range of about 200 μm to 600 μm. Here, the thickness of the adhesive film can be the thickness of the adhesive film between the outer substrate and the optical modulation device, such as the distance between the two.

[0148] In addition to the above-described structures, optical devices may also include necessary structures where appropriate, and examples of such structures include, but are not limited to, buffer layers, retardation layers, optical compensation layers, anti-reflective layers and / or hard coatings.

[0149] The optical device may include the step of encapsulating an optical modulation device between a first outer substrate and a second outer substrate disposed opposite each other using an encapsulant through a pressure process.

[0150] At this point, there are no particular restrictions on the specific type of pressurization process. For example, the pressurization process can be a high-pressure autoclave process.

[0151] Therefore, a method for manufacturing an optical device may include the step of encapsulating an optical modulation device between a first outer substrate and a second outer substrate disposed opposite each other using an adhesive film via an autoclave process.

[0152] The autoclave process can be carried out by placing the adhesive film and the light modulation device between the outer substrate according to the desired encapsulation structure, and then heating / pressing.

[0153] For example, an optical device can be formed by heating / pressurizing a laminate in which an outer substrate, an adhesive film, an optical modulation device, an adhesive film, and an outer substrate are arranged in this order, and the adhesive film is also disposed on the side of the optical modulation device, through an autoclave process.

[0154] There are no particular restrictions on the conditions of the autoclave process. For example, the process can be carried out at appropriate temperatures and pressures depending on the type of encapsulant (adhesive film) applied. Typical autoclave process temperatures are approximately 40°C or higher, 50°C or higher, 60°C or higher, 70°C or higher, 80°C or higher, 90°C or higher, or 100°C or higher, and pressures are 2 atmospheres or more, but are not limited to these. Upper limits for process temperatures can be approximately 200°C or lower, 190°C or lower, 180°C or lower, or around 170°C or lower, and upper limits for process pressures can be approximately 10 atmospheres or less, 9 atmospheres or less, 8 atmospheres or less, 7 atmospheres or less, or around 6 atmospheres or less.

[0155] Such optical devices can be used in a variety of applications, such as eye-wearing devices like sunglasses or eye-wearing devices for AR (augmented reality) or VR (virtual reality), exterior walls of buildings, or sunroofs of vehicles.

[0156] Invention Effects

[0157] This application provides an optical modulation device, an optical device, or a method thereof that can stably maintain the designed optical properties even after a packaging process in which pressure is applied, such as an autoclave process. This application also provides an optical modulation device, an optical device thereof, or a method thereof that can stably maintain the orientation state of the optical modulation layer while effectively ensuring the adhesion between the upper and lower substrates. Attached Figure Description

[0158] Figures 1 to 3 This is a schematic diagram of an exemplary optical modulation device of this application.

[0159] Figure 4 This is a diagram used to illustrate the process of obtaining the refractive index anisotropy of the optical modulation layer. Detailed Implementation

[0160] The present application will be described in detail below by way of embodiments, but the scope of the present application is not limited to the following embodiments.

[0161] 1. Phase difference assessment

[0162] The in-plane retardation (Rin) of the film for light at a wavelength of 550 nm was measured using a UV / VIS beam splitter 8453 instrument from Agilent Co., Ltd. Two polarizers were mounted in the UV / VIS beam splitter with their transmission axes orthogonal to each other. The polymer film was then mounted between the two polarizers with its slow axis forming a 45-degree angle with the transmission axes of each polarizer. Transmittance was then measured according to wavelength. The order of phase retardation for each peak was obtained from the transmittance plot according to wavelength. Specifically, the waveforms in the transmittance plot according to wavelength satisfy the following equation A, and the maximum peak value (T) in the sinusoidal waveform... 最大 The condition satisfies the following equation B. In equation A, λ... 最大 In the case of equation A, since T is the same as T in equation B, the equation is extended. Since the equation is also extended for n+1, n+2, and n+3, the equations for n and n+1 are rearranged to eliminate R, and n is rearranged into equations for λn and λn+1, thus yielding the following equation C. Since n and λ can be known based on the fact that T in equation A is the same as T in equation B, R is obtained for each of λn, λn+1, λn+2, and λn+3. A linear trend line of R values ​​based on wavelength is obtained for four points, and the R value for 550nm is calculated. The function of the linear trend line is Y = ax + b, where a and b are constants. The value of Y when x of the function is replaced by 550nm is the Rin value for light with a wavelength of 550nm.

[0163] [Equation A]

[0164] T = sin 2 [(2πR / λ)]

[0165] [Equation B]

[0166] T = sin 2 [((2n+1)π / 2)]

[0167] [Equation C]

[0168] n=(λn-3λn+1) / (2λn+1+1-2λn)

[0169] In the above text, R represents the in-plane delay (Rin), λ represents the wavelength, and n represents the nodal degree of the sine wave.

[0170] 2. Thickness assessment of the light modulation layer (liquid crystal layer)

[0171] Since the thickness of the optical modulation layer (i.e., the cell gap) is consistent with the height of the spacers, the height of the spacers is measured and defined as the cell gap. The height of the spacers is determined using a measuring device (Optical Profiler, manufactured by Nanosystem, Nano View-E1000).

[0172] 3. Evaluation of the refractive index anisotropy of the light modulation layer (liquid crystal layer)

[0173] Refractive index anisotropy (Δn) was evaluated using an Abbe refractometer in the following manner. A perpendicular alignment film was coated onto the surfaces of the measuring prism and illumination prism of the Abbe refractometer, and the liquid crystal compound to be measured was coated onto the measuring prism, which was then covered with the illumination prism. The liquid crystal compound was perpendicularly oriented by the perpendicular alignment forces at the two interfaces. The liquid crystal compound applied in the above process was only the liquid crystal compound applied to the transmittance-variable layer without mixing with other materials such as dichroic dyes. Then, as... Figure 4 As shown, when a linear polarizer is applied to the eyepiece side and illuminated with the light to be observed, the following can be obtained: Figure 4 The values ​​θe and θo are shown in the diagram. The unusual refractive index (ne = npsinθe) and the ordinary refractive index (no = npsinθo) can be obtained by measuring the refractive index (np) and angles (θe and θo) of the prism, where the difference (ne - no) can be defined as refractive index anisotropy. The reference wavelength for the measurement is approximately 550 nm.

[0174] 4. Pitch evaluation of the optical modulation layer (liquid crystal layer)

[0175] The pitch (p) of the twist orientation was measured using a wedge cell measurement method. Specifically, the pitch (p) of the twist orientation was measured by the method described in D. Podolskyy et al., Simple method for accurate measurements of the cholesteric pitch using a stripe-wedge Grandjean-Cano cell (Liquid Crystals, Vol. 35, No. 7, July 8, 2008, 789-791).

[0176] Example 1.

[0177] Manufacturing of optical modulation devices

[0178] As the first substrate for the optical modulation device, a PET (poly(ethylene terephthalate)) film (manufactured by Toyobo, SRF product) with a thickness of approximately 80 μm is used. The in-plane phase difference (550 nm) of the PET film is approximately 9,000 nm. An optically anisotropic film (a negative C film satisfying Formula 3), an ITO (indium tin oxide) layer, and a silicone pressure-sensitive adhesive layer are sequentially formed on the surface of the PET film (a laminate structure of first substrate / optically anisotropic film / ITO layer / pressure-sensitive adhesive layer). The optically anisotropic film is formed by coating the substrate with a polyamide coating liquid (in which the polyamide obtained by polymerizing terephthalic acid, isophthalic acid, and 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine is diluted to a concentration of 5.3% by weight in a dimethylacetamide solution), and then drying it, wherein the phase difference in the thickness direction is approximately -220. The ITO layer is formed by a known deposition method, and the pressure-sensitive adhesive is formed to a thickness of about 10 μm by rod coating an organosilicon pressure-sensitive adhesive composition (Shinetsu, KR3700) onto the ITO layer and drying it at about 150°C for 5 minutes.

[0179] As the second substrate, a PET (polyethylene terephthalate) film (manufactured by SKC, a highly stretched PET product) with an ITO (indium tin oxide) layer deposited on the first surface and a thickness of approximately 145 μm is used. The in-plane phase difference (550 nm) of the PET film is approximately 10,000 nm. As honeycomb-type spacers, spacers with a spacing of approximately 350 μm and a linewidth of approximately 10 μm are formed on the ITO layer of the PET film, wherein the regular hexagons (closed patterns) constituting the honeycomb are formed. The height of the spacers is formed to satisfy the thickness (cell gap) of the liquid crystal layer (light modulation layer) summarized in Table 1 below. A vertical alignment film (5661LB3, Nissan) with a thickness of approximately 300 nm is formed on the spacers. The vertical alignment film is formed by rubbing it in one direction. The rubbing direction is perpendicular to the slow axis direction of the second substrate.

[0180] Subsequently, a liquid crystal composition is coated on the surface of the vertical alignment film of the second substrate, and a pressure-sensitive adhesive layer of the first substrate is laminated to form a coating surface facing the liquid crystal composition, thereby preparing a light modulation film layer. At this time, the positions of the slow axes of the first and second substrates are adjusted so that the axes are parallel to each other.

[0181] Here, a composition comprising a liquid crystal compound (Merck, MAT-19-753) and a chiral dopant (Merck, S811) is used as the liquid crystal composition. The content of the chiral dopant is adjusted so that the pitch of the twisted orientation (chiral pitch) (p) can satisfy Table 1 below.

[0182] Manufacturing of optical devices

[0183] An adhesive film (encapsulant) is used to encapsulate the manufactured light modulation film layer together with a PVA (polyvinyl alcohol) polarizing layer between two outer substrates. During encapsulation, the PVA polarizing layer is present on the second surface of each of the first and second substrates of the light modulation film layer, wherein the absorption axis of the PVA polarizing layer on the second surface of the second substrate is perpendicular to the slow axis of the second substrate, and the absorption axis of the PVA polarizing layer on the second surface of the first substrate is horizontal to the slow axis of the first substrate. A thermoplastic polyurethane adhesive film (thickness: approximately 0.38 mm, manufacturer: Argotec, product name: ArgoFlex) is used as the adhesive film, and a glass substrate with a thickness of approximately 3 mm is used as the outer substrate. The first outer substrate, adhesive film, PVA polarizing layer, adhesive film, light modulation film layer, adhesive film, PVA polarizing layer, adhesive film, and second outer substrate are laminated in this order, with adhesive films also applied to all sides of the light modulation film layer to prepare the laminate. Subsequently, an autoclave process is performed at a temperature of approximately 100°C and a pressure of approximately 2 atmospheres to manufacture the optical device.

[0184] Examples 2 to 9.

[0185] The light modulation device and optical device were manufactured in the same manner as in Example 1, except that the thickness (cell gap, t) and pitch of the twisted orientation of the liquid crystal layer (light modulation layer) were adjusted as shown in Table 1 below when manufacturing the light modulation device (in Table 1 below, Δn is the refractive index anisotropy of the liquid crystal layer, t is the thickness of the liquid crystal layer, p is the pitch, and K is the value calculated by Δn×p / t).

[0186] [Table 1]

[0187]

[0188] Comparative examples 1 to 7.

[0189] The light modulation device and optical device were manufactured in the same manner as in Example 1, except that the thickness (cell gap, t) and pitch of the twisted orientation of the liquid crystal layer (light modulation layer) were adjusted as shown in Table 2 below when manufacturing the light modulation device (in Table 2 below, Δn is the refractive index anisotropy of the liquid crystal layer, t is the thickness of the liquid crystal layer, p is the pitch, and K is the value calculated by Δn×p / t).

[0190] [Table 2]

[0191]

[0192] The transmittance was evaluated with approximately 60V applied to the optical modulation device and optical device of each of the above embodiments and comparative examples, and the results are summarized in Tables 3 and 4 below. Specifically, the transmittance of the optical modulation device is the transmittance before the pressurization process (autoclave), and the transmittance of the optical device is the transmittance after the pressurization process (autoclave). The rate of change of transmittance before and after the pressurization process is also summarized in Tables 3 and 4 below. A turbidity meter (NDH-5000SP) was used to evaluate the transmittance.

[0193] [Table 3]

[0194]

[0195] [Table 4]

[0196]

[0197] As summarized in Tables 3 and 4, in the apparatus of the embodiments, the transmittance is maintained stably even after the pressurization process (autoclave process), while the light modulation device exhibits appropriate transmittance.

[0198] On the other hand, in the comparative examples, the transmittance changed significantly before and after the pressurization process, or the transmittance itself did not reach the expected value. Furthermore, in comparative examples 5 to 7, the liquid crystal compound itself was poorly oriented, making it impossible to measure the transmittance.

Claims

1. An optical device comprising: a first outer substrate and a second outer substrate disposed opposite each other; and a light modulating device encapsulated with an encapsulant between the first outer substrate and the second outer substrate, wherein the light modulating device includes a light modulating film layer, wherein the light modulating film layer includes: a first substrate and a second substrate; and a liquid crystal layer, wherein the first substrate and the second substrate each have a first surface and a second surface, wherein the first substrate and the second substrate are disposed opposite each other; wherein the liquid crystal layer is between the first substrate and the second substrate and is formed so as to enable a twisted alignment, wherein a silicone pressure-sensitive adhesive layer is formed on the first surface of the first substrate, a liquid crystal alignment film is formed on the first surface of the second substrate, and the first substrate and the second substrate are disposed so that the first surfaces face each other, wherein the liquid crystal alignment film is a vertical alignment film, and wherein a K value of Equation 1 below is in a range of 0.19 to 0.3: [Equation 1] K = Δn x p / t wherein Δn is a refractive index anisotropy of the liquid crystal layer, p is a pitch of the twisted alignment, and t is a thickness of the liquid crystal layer.

2. The optical device according to claim 1, wherein no liquid crystal alignment film is formed on the first substrate.

3. The optical device according to claim 1, wherein the refractive index anisotropy Δn of the liquid crystal layer is in a range of 0.01 to 0.

5.

4. The optical device according to claim 1, wherein the pitch p of the twisted alignment is in a range of 1 μm to 100 μm.

5. The optical device according to claim 1, wherein the thickness t of the liquid crystal layer is in a range of 0.5 μm to 50 μm.

6. The optical device according to claim 1, wherein a ratio t / p of the thickness t of the liquid crystal layer to the pitch p of the twisted alignment is less than 1.

7. The optical device according to claim 1, wherein the liquid crystal layer is formed so that an initial state of the liquid crystal layer is a vertical alignment state, and the liquid crystal layer is capable of enabling a twisted alignment upon application of a voltage.

8. The optical device according to claim 1, wherein the liquid crystal layer includes a liquid crystal compound and a chiral dopant.

9. The optical device according to claim 1, wherein the first substrate or the second substrate has an in-plane phase difference of 500 nm or more for light having a wavelength of 550 nm.

10. The optical device according to claim 1, wherein the light modulating device further includes a polarizing layer disposed on the second surface of the first substrate or the second substrate.

11. The optical device according to claim 1, wherein the light modulating device further includes a polarizing layer disposed on the second surface of the first substrate or the second substrate, wherein the first substrate or the second substrate has an in-plane phase difference of 500 nm or more for light having a wavelength of 550 nm, and wherein a small angle between a slow axis of the first substrate or the second substrate and an absorption axis of the polarizing layer is in a range of 80 degrees to 100 degrees.

12. The optical device according to claim 1, wherein the light modulation device further comprises an optically anisotropic film present between the first substrate or the second substrate and the liquid crystal layer and satisfying the following formula 3: [Formula 3] nz < ny ny is a refractive index of the optically anisotropic film in a fast axis direction for a 550 nm wavelength, and nz is a refractive index of the optically anisotropic film in a thickness direction for a 550 nm wavelength. wherein 13. A method for manufacturing the optical device according to claim 1, comprising a step of encapsulating the light modulation device between a first outer substrate and a second outer substrate disposed opposite to each other by a pressurization process using an encapsulant.

14. A window comprising the optical device according to claim 1.

15. A sunroof comprising the optical device according to claim 1. ​

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