Optical modulation device and automobile

Abstract

The present application can provide a light modulation device including an anisotropic plastic substrate and a car in which the light modulation device is applied to a sunroof and / or glass, and can provide a car capable of eliminating or improving a disadvantage caused by the application of an anisotropic plastic substrate while using the light modulation device.

Description

Technical Field

[0001] This application claims priority to Korean Patent Application No. 10-2020-0092400, filed on July 24, 2020, the disclosure of which is incorporated herein by reference in its entirety.

[0002] This application relates to optical modulation devices and automobiles. Optical modulation devices may be incorporated into the sunroof or glass of an automobile. Background Technology

[0003] During seasons with high levels of sunlight, or in regions with high levels of sunlight such as the tropics, large amounts of sunlight enter vehicles through sunroofs or windows. This sunlight causes the vehicle's temperature to rise, among other things.

[0004] Therefore, during periods of high sunlight intensity, one approach is to physically install devices on skylights or glass to block sunlight.

[0005] However, when using the light modulation device described above, there is a problem of non-uniformity in light transmittance depending on the perspective of a person sitting in the vehicle, and therefore there is a problem of non-uniformity (e.g., black bands) depending on the viewing direction. Summary of the Invention

[0006] Technical issues

[0007] This application relates to light modulation devices and automobiles. Specifically, one object is to provide a light modulation device for use in an automobile and intended to enable the achievement of uniform transmittance independent of the field of vision of automobile passengers, as a light modulation device used as a sunroof, front glass, rear glass, or side glass of an automobile, or an automobile incorporating such a light modulation device.

[0008] Technical solution

[0009] In this specification, the terms used to define angles, such as vertical, horizontal, orthogonal, or parallel, mean substantially vertical, horizontal, orthogonal, or parallel to the intended effect, and the range of vertical, horizontal, orthogonal, or parallel includes errors such as manufacturing errors or deviations (variations). For example, each of the foregoing cases may include an error within approximately ±15 degrees, or an error within approximately ±14 degrees, an error within approximately ±13 degrees, an error within approximately ±12 degrees, an error within approximately ±11 degrees, an error within approximately ±10 degrees, an error within approximately ±9 degrees, an error within approximately ±8 degrees, an error within approximately ±7 degrees, an error within approximately ±6 degrees, an error within approximately ±5 degrees, an error within approximately ±4 degrees, an error within approximately ±3 degrees, an error within approximately ±2 degrees, an error within approximately ±1 degree, or an error within approximately ±0.5 degrees.

[0010] Unless otherwise stated, the physical properties mentioned herein refer to physical properties measured at room temperature when the temperature affects the relevant physical properties.

[0011] In this specification, the term room temperature refers to the temperature under conditions of no special heating or cooling, and may mean a temperature in the range of about 10°C to 30°C, such as 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.

[0012] Unless otherwise stated, the phase difference and refractive index mentioned herein refer to the refractive index for light with a wavelength of approximately 550 nm.

[0013] 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, either the angle measured in the clockwise direction or the angle measured in the counterclockwise direction may be represented as a positive number, while the other angle may be represented as a negative number.

[0014] This application relates to a light modulation device used in or included in a sunroof or glass of an automobile. This application also relates to an automobile in which the light modulation device is included in a sunroof or glass.

[0015] Here, as Figure 1 As shown, the glass can be the vehicle's front windshield 100, side windshield 200, or rear windshield 300. The sunroof or glass can be entirely composed of light modulation devices, or at least a portion thereof can be composed of light modulation devices.

[0016] In this specification, the term "optical modulation device" may refer to a device capable of switching between at least two or more different optical states. Here, different optical states may refer to states with different transmittance, color, and / or haze.

[0017] 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.

[0018] In one instance, the optical modulation device may be a device capable of switching between at least a transparent mode state and a black mode state, or a device capable of switching between a high-reflectivity mode state and a low-reflectivity mode state.

[0019] The transmittance of the optical modulation device in transparent mode can be at least 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 about 80% or greater.

[0020] 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, 5% or less, 1% or less, or 0.5% or less. Since higher transmittance in transparent mode is more advantageous, and lower transmittance in black mode is more advantageous, there are no particular limitations on the upper limit and lower limit of transmittance in transparent mode and black mode. In one example, the upper limit of transmittance in transparent mode can be approximately 100%, and the lower limit of transmittance in black mode can be approximately 0%.

[0021] In one example, in an optical modulation device capable of switching between a transparent mode state and a black mode state, the difference between the transmittance in the transparent mode state and the transmittance in the black mode state (transparent mode - black mode) can be 15% or greater, 20% or greater, 25% or greater, 30% or greater, 35% or greater, or 40% or greater, or it can be 90% or less, 85% or less, 80% or less, 75% or less, 70% or less, 65% or less, 60% or less, 55% or less, 50% or less, or 45% or less.

[0022] Transmittance can be 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] The optical modulation device of this application can be designed to switch between at least two or more states selected from any one of a transparent mode state, a black mode state, and a color mode state, as well as other states. 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] Therefore, the vehicle described in this application may also include a control circuit capable of switching the optical modulation device or an external signal application device. There are no particular limitations on the method of configuring such additional devices, and known devices may be appropriately applied.

[0027] The optical modulation device of this application may include an optical modulation film layer having two substrates arranged opposite each other and an optical modulation layer positioned between the substrates as a basic unit. Figure 2 This is a diagram illustrating an example of an optical modulation film layer. As shown, the optical modulation film layer may include a first substrate 100 and a second substrate 200 disposed opposite each other. Typically, the first substrate 100 and the second substrate 200 are attached by a sealant 300.

[0028] A functional layer 1001 is formed on one surface of a first substrate 100 (hereinafter referred to as the first surface), and a liquid crystal alignment film 2001 is formed on one surface of a second substrate 200 (hereinafter referred to as the first surface). A light modulation layer is positioned between the first substrate 100 and the second substrate 200, which are disposed opposite to each other. When the light modulation layer is a liquid crystal layer, typically, a liquid crystal alignment film is formed on both the surfaces of the first substrate 100 and the second substrate 200. Therefore, the functional layer 1001 formed on the first surface of the first substrate 100 can also be a liquid crystal alignment film. In another example, the functional layer 1001 can be a pressure-sensitive adhesive layer or an adhesive layer. The inventors have determined that, as the functional layer 1001 of the first substrate 100, liquid crystal alignment suitable for vehicles is achieved even when a suitable pressure-sensitive adhesive layer or an adhesive layer is formed instead of a liquid crystal alignment film. Furthermore, although not shown in the figures, spacers for maintaining the gap (cell gap) between the first substrate and the second substrate may be present in either the first substrate or the second substrate of the light modulation film layer. When a pressure-sensitive adhesive layer or adhesive layer is formed on the first substrate 100 as a functional layer 1001, the pressure-sensitive adhesive layer or adhesive layer 1001 is attached to the spacer, thereby greatly improving the lamination force between the first substrate and the second substrate.

[0029] In this specification, the first surface of the substrate refers to either the main surface or the opposite surface of the substrate, and the second surface refers to the other surface of the main surface or the opposite surface of the substrate.

[0030] As a substrate, any known substrate material can be used without any particular restrictions. For example, isotropic or anisotropic substrates can be used. The term isotropic substrate means a substrate whose refractive index does not depend on the polarization direction of the wave, while anisotropic substrate means a substrate whose refractive index varies according to the polarization state of the light. Inorganic substrates such as glass substrates, crystalline or amorphous silicon substrates, or quartz substrates can be used; 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. The thickness of such substrates is not particularly limited and can be selected within an appropriate range.

[0031] In this application, an anisotropic substrate, specifically an anisotropic plastic substrate, can be used to ensure mechanical, flexible, and optical properties suitable for vehicles. Such a substrate, due to its inherent properties, can provide mechanical, flexible, and optical properties suitable for optical modulation devices used in vehicles.

[0032] Among anisotropic plastic substrates, those with a certain level or higher of optical anisotropy can exhibit mechanical properties and flexibility particularly suitable for vehicles. For example, in this application, plastic substrates with an in-plane phase difference of at least 400 nm or greater can be used as substrates.

[0033] In this specification, the in-plane phase difference (Rin) means the value calculated by the following formula 1.

[0034] [Formula 1]

[0035] Rin = d × (nx - ny)

[0036] In Equation 1, Rin is the in-plane phase difference, d is the thickness of the substrate, nx is the refractive index of the substrate in the slow axis direction, ny is the refractive index of the substrate in the fast axis direction, and it is the refractive index in the in-plane direction orthogonal to the slow axis direction.

[0037] In another example, the in-plane phase difference can be approximately 400 nm or greater, 450 nm or greater, 550 nm or greater, 600 nm or greater, 650 nm or greater, 700 nm or greater, 750 nm or greater, 800 nm or greater, 850 nm or greater, 900 nm or greater, 950 nm or greater, 1000 nm or greater, 2000 nm or greater, 3000 nm or greater, 4,000 nm or greater, 5,000 nm or greater, 6,000 nm or greater, 7,000 nm or greater, 8,000 nm or greater, 9,000 nm or greater, 10,000 nm or greater, 11,000 nm or greater, 12,000 nm or greater, 13,000 nm or greater, 14,000 nm or greater, or 15,000 nm or greater. In addition, the in-plane phase difference of each substrate can be approximately 50,000 nm or less, approximately 40,000 nm or less, approximately 30,000 nm or less, 20,000 nm or less, 18,000 nm or less, 16,000 nm or less, 15,000 nm or less, or approximately 12,000 nm or less.

[0038] Polyester film substrates, such as PET (polyethylene terephthalate) substrates, are commonly known as plastic substrates with phase difference. However, the types of substrates that can be used in this application are not limited to these, and all types of substrates can be used as long as they have such in-plane phase difference. Furthermore, at least two substrates applied to the light modulation film layer can have such in-plane phase difference, but at least one substrate can have such in-plane phase difference.

[0039] Substrates exhibiting such anisotropy possess mechanical, flexible, and optical properties suitable for vehicles; however, due to the inherent optical anisotropy of the substrate, it may provide optical inhomogeneities depending on the passenger's field of vision when applied to a vehicle. However, the optical modulation device designed according to this application can improve or eliminate these drawbacks while utilizing the substrate.

[0040] For example, when a light modulation device is applied to or included in a sunroof of a car, the slow axis of the first anisotropic substrate and / or the second anisotropic substrate can be formed parallel to the width direction of the car. In this case, the fact that the slow axis is formed parallel to the width direction of the car can mean, for example, that when a fastening device or fastener is present in the light modulation device that can be mounted at the sunroof location, the fastener or fastener ensures that the slow axis of the substrate is arranged parallel to the width direction of the car when the light modulation device is mounted at the sunroof location using the fastener or fastener. In another example, this can mean that if the shape of the light modulation device is configured to have the same shape as the shape of the car's sunroof and the light modulation device is mounted to the car's sunroof according to that shape, the shape of the light modulation device is manufactured such that the slow axis of the substrate is arranged parallel to the width direction of the car.

[0041] Therefore, in one instance, a fastening device or fastener that can be installed on the sunroof of a car may exist in the light modulation device or the light modulation device may have the same shape as the sunroof, and the fastening device, fastener or shape may be determined such that when the light modulation device is installed on the sunroof of the car according to the fastening device, fastener or shape, the slow axis of the first anisotropic substrate or the second anisotropic substrate is arranged parallel to the width direction of the car.

[0042] There are no particular limitations on the method of forming the above-described fastening device or fastening part on the optical modulation device or configuring the optical modulation device to have the above-described shape, and known methods can be applied.

[0043] For example, when a light modulation device is applied to, or included in, the front, rear, or side windows of an automobile, the slow axis of the first anisotropic substrate and / or the second anisotropic substrate can be formed parallel to the longitudinal direction of the automobile. In this case, the fact that the slow axis is formed parallel to the longitudinal direction of the automobile can mean, for example, that when a fastening device or fastener is present in the light modulation device that can be mounted at the front, rear, or side window position of the automobile, the fastening device or fastener ensures that the slow axis of the substrate is parallel to the longitudinal direction of the automobile when the light modulation device is mounted at the front, rear, or side window position using the fastening device or fastener. In another example, this can mean that if the shape of the light modulation device is configured to have the same shape as the front, rear, or side window of the automobile, and the light modulation device is mounted to the front, rear, or side window of the automobile according to this shape, the shape of the light modulation device is manufactured such that the slow axis of the substrate is parallel to the longitudinal direction of the automobile.

[0044] Therefore, in one example, a fastening device or fastener that can be installed on the front, rear, or side glass of a vehicle is present in the light modulation device or the light modulation device has the same shape as the front, rear, or side glass. The fastening device, fastener, or shape can be determined such that when the light modulation device is installed on the front, rear, or side glass of the vehicle according to the fastening device, fastener, or shape, the slow axis of the first anisotropic substrate or the second anisotropic substrate is arranged parallel to the longitudinal direction of the vehicle.

[0045] There are no particular limitations on the method of forming the above-described fastening device or fastening part on the optical modulation device or configuring the optical modulation device to have the above-described shape, and known methods can be applied.

[0046] For example, when two anisotropic substrates are used as two substrates in the optical modulation film layer of this application (e.g., Figure 2 When the first substrate 100 and the second substrate 200 are used, the two substrates (the first substrate and the second substrate) are suitably arranged such that their optical axes are parallel to each other. In this specification, unless otherwise stated, the optical axis of the anisotropic substrate refers to the slow axis of the anisotropic substrate, and unless otherwise stated, the optical axis of the polarizing layer refers to the absorption axis of the polarizing layer. The absorption axis of the polarizing layer is perpendicular or horizontal to the slow axis of the first anisotropic substrate or the second anisotropic substrate.

[0047] In an optical modulation film, the optical modulation layer existing between the substrates is a functional layer capable of changing the transmittance, reflectance, haze, and / or color of the optical modulation device, either alone or in combination with other components, depending on whether an external signal is applied. Such an optical modulation layer may be referred to herein as an active optical modulation layer.

[0048] In this specification, an external signal can refer to an external factor that can affect the behavior of the material contained in the optical modulation layer (e.g., an optical modulation material), such as an external voltage. Therefore, a state without any external signal can mean a state in which no external voltage is applied.

[0049] 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.

[0050] 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 an active liquid crystal 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. As the liquid crystal compound, any type of liquid crystal compound can be used, as long as the orientation direction can be changed by applying an external signal. For example, smectic liquid crystal compounds, nematic liquid crystal compounds, 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.

[0051] The liquid crystal layer may contain a liquid crystal compound with positive or negative dielectric anisotropy. For the purposes of this application, the absolute value of the dielectric anisotropy of the liquid crystal may be appropriately chosen. 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 director and the direction of the electric field generated by the applied voltage are substantially horizontal, 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 director and the direction of the electric field generated by the applied voltage are substantially perpendicular.

[0052] The driving modes of a liquid crystal layer can be exemplified as 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, etc.

[0053] If desired, the light modulation layer for the liquid crystal layer may also contain a dichroic dye for controlling the variable transmittance characteristics together with the liquid crystal compound. For example, when the light modulation device includes a polarizing layer, the light modulation layer for the liquid crystal layer may also contain a dichroic dye. In this specification, the term "dye" may mean a material capable of strongly absorbing and / or deforming light in at least part or all of the visible light region (e.g., in the wavelength range of 400 nm to 700 nm), and the term "dichroic dye" may mean a material capable of anisotropically absorbing light in at least part or all of the visible light region. Such dyes are, for example, called azo dyes or anthraquinone dyes, but are not limited thereto.

[0054] In one example, when the light modulation device includes a polarizing layer, the light modulation layer is a liquid crystal layer comprising a liquid crystal compound and a dichroic dye, which can be a so-called guest-host liquid crystal layer (guest-host liquid crystal cell). The term "GHLC layer" can refer to a functional layer in which the dichroic dyes are arranged together according to the alignment of the liquid crystals, thereby exhibiting anisotropic light absorption characteristics with respect to the alignment direction of the dichroic dyes and the direction perpendicular to said alignment direction. 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 can be called a p-type dye, and if the absorptivity of light polarized in the short axis direction is large, it can be called an n-type dye. In one example, when a p-type dye is used, polarized light vibrating in the long axis direction of the dye can be absorbed, while polarized light vibrating in the short axis direction of the dye can be less absorbed and transmitted. In the following, unless otherwise stated, the dichroic dye is considered to be a p-type dye.

[0055] An optical modulation film layer, including a host and guest liquid crystal layer as an optical modulation layer, can be used as an active polarizing layer (active polarizer). In this specification, the term "active polarizing layer (active polarizer)" can refer to a functional element capable of controlling anisotropic light absorption according to the application of an external signal. Such an active polarizing layer can be distinguished from a passive polarizing layer, as described below, which has constant light absorption or light reflection characteristics regardless of the applied external signal. The host and guest liquid crystal layer can control the anisotropic light absorption of polarized light in the direction parallel to the alignment direction of the dichroic dyes and in the direction perpendicular to it by controlling the alignment of the liquid crystal and the dichroic dyes. Since the alignment of the liquid crystal and the dichroic dyes can be controlled by applying an external signal, such as a magnetic field or an electric field, the host and guest liquid crystal layer can control anisotropic light absorption according to the application of an external signal.

[0056] The liquid crystal layer, serving as the 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.

[0057] Chiral dopants can be used without any particular restrictions, provided they can induce the desired twisting without impairing the liquid crystal properties (e.g., nematic regularity). Chiral dopants used to induce rotation in liquid crystal molecules need to include at least chirality in their molecular structure. Examples of chiral dopants include, for instance, compounds having one or two or more asymmetric carbons; compounds with asymmetric sites on heteroatoms, such as chiral amines or chiral sulfoxides; or compounds with axial asymmetry and optically active sites, such as 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, etc., can be used as chiral dopants.

[0058] Furthermore, there are no particular limitations on the ratio of chiral dopants, but chiral dopants can be included in a ratio such that the ratio (d, inter-cell gap) of the thickness of the light modulation layer to the pitch (p) of the helical structure of the liquid crystal compound generated by the addition of chiral dopants (d / p) can be 0.05 or greater, 0.1 or greater, 0.15 or greater, 0.2 or greater, 0.25 or greater, 0.3 or greater, 0.35 or greater, approximately 0.4 or greater, approximately 0.45 or greater, approximately 0.5 or greater, approximately 0.55 or greater, approximately 0.6 or greater, approximately 0.65 or greater, approximately 0.7 or greater, approximately 0.75 or greater, or approximately 0.8 or greater. This ratio (d / p) is related to the orientation of the liquid crystal compound induced by the pressure-sensitive adhesive layer or adhesive layer and the liquid crystal alignment film, allowing for an orientation state suitable for the application. Furthermore, a higher d / p ratio allows the optical modulation device to more effectively achieve both transparent and black states, and in particular, enables the device to effectively suppress transmittance in the black state. However, if an excessive amount of chiral dopant is added to increase the d / p ratio, there is a problem of reduced orientation stability, particularly orientation stability with respect to temperature changes or at high temperatures. However, as described below, when two chiral dopants are applied according to this application, excellent orientation stability can be ensured even when the d / p ratio remains high. In another example, the d / p ratio can be 2 or less, 1.5 or less, 1 or less, less than 1, 0.95 or less, 0.9 or less, or 0.85 or less.

[0059] The pitch (p) of the optical modulation layer (liquid crystal layer) with chiral dopant applied in the so-called twisted orientation mode or cholesteric orientation mode can be measured using a wedge cell measurement method, and can be measured using the method described in D. Podolskyy et al.'s Simple method for accurate measurements of the cholesteric pitch using astripe-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 formula 100 / (HTP (Helical Twisting Power) × pitch (nm)), which can be chosen by considering the desired pitch (p) at an appropriate ratio.

[0060] There are no particular restrictions on the types of the additional components (e.g., dichroic dyes or chiral dopants) included in the light modulation layer along with the liquid crystal compound, wherein known components may be used, and in addition to the above components, the light modulation layer may also contain any other known components as required.

[0061] 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 in the light modulation film layer. Known vertical alignment films, horizontal alignment films, or other alignment films can be used as liquid crystal 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 used.

[0062] There are no particular limitations on the type of pressure-sensitive adhesive layer or adhesive layer that can be applied as a functional layer to the surface of the first substrate. For example, it has been determined that various types of pressure-sensitive adhesives or adhesives, known in the industry as so-called OCA (Optically Clear Adhesive) or OCR (Optically Clear Resin), can be combined with liquid crystal alignment films to induce suitable orientation of liquid crystal compounds. As pressure-sensitive adhesives or adhesives, for example, acrylic, silicone-based, epoxy-based, or urethane-based pressure-sensitive adhesives or adhesives can be applied.

[0063] 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 be combined with liquid crystal alignment films (especially vertical alignment films) to induce the orientation state of liquid crystal compounds suitable for a particular purpose.

[0064] As a silicone-based pressure-sensitive adhesive or binder, a cured product of a curable silicone adhesive or pressure-sensitive adhesive composition (hereinafter 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.

[0065] In one example, the curable silicone composition is an addition-curable silicone composition, which may comprise (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 silicone compounds can, for example, form cured products through an addition reaction in the presence of a catalyst such as a platinum catalyst.

[0066] (1) The organopolysiloxane, which is the main component constituting the 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) the organopolysiloxane, 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 the side chain of the molecular chain. In addition, in (1) the organopolysiloxane, the types of substituents that may be included besides the alkenyl groups described above may include: alkyl, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, or heptyl; aryl, such as phenyl, tolyl, xylyl, or naphthyl; aralkyl, such as benzyl or phenethyl; halogen-substituted alkyl, such as chloromethyl, 3-chloropropyl, or 3,3,3-trifluoropropyl; etc., and methyl or phenyl is generally used, but not limited thereto.

[0067] (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. Molecular structures with linear molecular structures are usually used, but are not limited to this.

[0068] (1) More specific examples of organopolysiloxanes may include dimethylsiloxane-methylvinylsiloxane copolymers capped at both ends of the molecular chain with trimethylsiloxane, methylvinylpolysiloxanes capped at both ends of the molecular chain with trimethylsiloxane, dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymers capped at both ends of the molecular chain with trimethylsiloxane, dimethylpolysiloxanes capped at both ends of the molecular chain with dimethylvinylsiloxane, methylvinylpolysiloxanes capped at both ends of the molecular chain with dimethylvinylsiloxane, dimethylsiloxane-methylvinylsiloxane copolymers capped at both ends of the molecular chain with dimethylvinylsiloxane, dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymers capped at both ends of the molecular chain with dimethylvinylsiloxane, dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymers capped at both ends of the molecular chain with dimethylvinylsiloxane, and those comprising 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 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. Furthermore, R... 2 It is an alkenyl group, specifically, it can be vinyl, allyl, butenyl, pentenyl, hexenyl or heptenyl, etc.

[0069] 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, and they can, for example, be bonded to the ends and / or side chains of the molecular chain. Furthermore, in (2) the organopolysiloxane, the types of substituents that may be included in addition to the hydrogen atoms bonded to silicon are not particularly limited, and may include, for example, alkyl, aryl, aralkyl, or halogen-substituted alkyl groups as mentioned in (1) the organopolysiloxane, among which methyl or phenyl is commonly used, but not limited thereto.

[0070] (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. Molecular structures with linear molecular structures are commonly used, but are not limited to this.

[0071] (2) More specific examples of organopolysiloxanes may include methylhydropolysiloxanes terminated at both ends of the molecular chain with trimethylsiloxane, dimethylsiloxane-methylhydropolymers terminated at both ends of the molecular chain with trimethylsiloxane, dimethylsiloxane-methylhydrosiloxane-methylphenylsiloxane copolymers terminated at both ends of the molecular chain with trimethylsiloxane, dimethylpolysiloxanes terminated at both ends of the molecular chain with dimethylhydrosiloxane, dimethylsiloxane-methylphenylsiloxane copolymers terminated at both ends of the molecular chain with dimethylhydrosiloxane, methylphenylpolysiloxanes terminated at both ends of the molecular chain with dimethylhydrosiloxane, and methylphenylpolysiloxanes 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, comprising 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, comprising 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 term refers to organopolysiloxane copolymers containing siloxane units, and mixtures of two or more of the aforementioned, but is 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.

[0072] (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.

[0073] 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.

[0074] In addition, addition-curable silicone compositions may also contain appropriate additives in suitable proportions as needed from the viewpoint of improving storage stability, handling properties and processability.

[0075] 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.

[0076] (a) The siloxane polymer can be, for example, a compound represented by Formula 1 below.

[0077] [Formula 1]

[0078] R 1 a R 2 b SiO c (OR 3 ) d

[0079] 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 numbers that are 0 or greater than and less than 1, a+b represents numbers that are greater than 0 and less than 2, c represents numbers that are greater than 0 and less than 2, d represents numbers that are greater than 0 and less than 4, and a+b+c×2+d equals 4.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] (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. Simultaneously, in the production of (a) siloxane polymers, suitable monofunctional alkoxysilanes can also be used in combination, depending on the purpose.

[0084] As (a) a siloxane polymer, commercially available organosiloxane polymers such as Shin-EtsuSilicone's X40-9220 or X40-9225 can be used; or GE Toray Silicone's XR31-B1410, XR31-B0270 or XR31-B2733 can be used.

[0085] As a condensable curable silicone composition, (b) a hydroxyl-containing siloxane polymer may be used, for example, a compound represented by Formula 2 below.

[0086] [Equation 2]

[0087]

[0088] 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.

[0089] 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.

[0090] (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 appropriate 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 above-mentioned (b) siloxane polymers, commercially available bifunctional organosiloxane polymers such as GE Toray Silicone's XC96-723, YF-3800, or YF-3804 can be used.

[0091] 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.

[0092] 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.

[0093] 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 adhesive or cohesive strength. 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.

[0094] The initial orientation of the liquid crystal compound formed by the liquid crystal alignment film and / or pressure-sensitive adhesive layer or adhesive layer in the liquid crystal layer, which 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 may or may not be twisted, thus existing in a twisted or cholesteric orientation. Here, initial orientation refers to the orientation in the state where no external signal, such as a voltage, is applied to the light modulation layer containing the liquid crystal compound.

[0095] 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.

[0096] 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. This 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.

[0097] 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.

[0098] The in-plane phase difference can be obtained using Formula 1 above.

[0099] 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, columnar spacers, or partition wall spacers, which are commonly used spacers, can be applied. In a suitable example, partition wall spacers can be used as spacers, particularly partition wall spacers in which the partition walls form at least one closed pattern. Examples of closed patterns formed by the partition wall spacers include hexagons (e.g., regular hexagons) or quadrilaterals (e.g., squares or rectangles). Partition wall spacers in which the closed pattern is hexagonal, especially regular hexagonal, are also referred to as so-called honeycomb-type spacers. It is well known that such honeycomb or quadrilateral partition wall spacers mean that when the shape of the partition wall spacers formed on the substrate is viewed in the normal direction of the substrate, the pattern formed by the partition wall spacers is honeycomb or quadrilateral. Honeycomb types can generally include combinations of regular hexagons, and quadrilaterals can include squares, rectangles, or combinations of squares and rectangles, etc. Partition wall spacers can be used as spacers, but are not limited to, considering the adhesion between the first substrate and the second substrate.

[0100] The pitch of the spacers can also be appropriately selected by considering factors such as desired adhesive strength or cell gap retention efficiency. For example, when applying spacers, the pitch can range from 50 μm to 2,000 μm. Methods for obtaining the pitch in spacers are known. For example, if the spacers are of a honeycomb type, the pitch is obtained by the spacing between opposite sides of the hexagons forming the honeycomb; in the case of quadrilaterals, the pitch is obtained by the lengths of the sides of the quadrilaterals. When the spacing between the opposite sides of the hexagons forming the honeycomb or the lengths of the sides of the quadrilaterals are not constant, their average value can be defined as the pitch.

[0101] For example, when the partition walls form a closed figure, the area of ​​the closed figure (i.e., the area of ​​a hexagon or quadrilateral, for example) can be in the range of, for example, about 1 mm² to 200 mm². When multiple closed figures are formed by the partition walls and the areas of the closed figures are different, the area is the arithmetic mean.

[0102] The linewidth of the spacers, for example, the width of each wall of the hexagons or quadrilaterals forming a honeycomb, can range from, for example, 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.

[0103] Within the above range, the unit gaps can be maintained appropriately, and the adhesion between the substrates can be maintained very well.

[0104] Methods for forming spherical spacers, columnar spacers, or partition spacers between substrates are known.

[0105] 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 pressure-sensitive adhesive layer or adhesive layer. Figure 2 Between 100 and 1001 in the middle) and / or between the first surface of the second substrate and the alignment film ( Figure 2 (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.

[0106] 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 their application is unrestricted.

[0107] The optical modulation device may include other additional components as needed, in addition to the optical modulation film layer. That is, depending on the driving mode, even with only the optical modulation film layer, the realization of 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 realization or switching of these modes.

[0108] 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. As an example of the above structure... Figure 3 Is Figure 2 In the structure where the polarizing layer 400 is only disposed on one side of the optical modulation film layer, Figure 4 Is Figure 2 In the 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 its shape is quadrilateral (square or rectangular), the sides of the quadrilateral and the absorption axis of the polarizing layer are appropriately arranged to be substantially perpendicular or horizontal to each other.

[0109] 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.

[0110] 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 such as 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.

[0111] 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 it is not limited to these.

[0112] like Figure 4 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.

[0113] In addition to the above-described structures, the optical modulation device may also include other necessary structures. For example, any other structures required to drive or use 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 that may be formed on the first surface of the first substrate.

[0114] There are no particular restrictions on the method of manufacturing 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 component.

[0115] This application also relates to automobiles including the aforementioned light modulation device. In the automobiles described in this application, such a light modulation device is included in a sunroof or glass. Here, as Figure 1 As shown, the glass can be the vehicle's front windshield 100, side windshields 200, or rear windshield 300. Furthermore, Figure 1 The image shows a sunroof 400 formed only in a portion of the vehicle roof, but the form of the sunroof in this application is not limited to this. Figure 1 The forms shown include, for example, designs in which a large portion of the vehicle roof is comprised of a sunroof. Furthermore, the light modulation device of this application can form an integral part of the sunroof or vehicle glass, or can be part of it.

[0116] In the automobile of this application, when the light modulation device includes an anisotropic substrate as the substrate in the above structure, in the case of a sunroof, the optical axis of the substrate can be parallel to the width direction of the automobile (i.e., Figure 1 (The direction of the dashed line is indicated by an example). Furthermore, in the case of vehicle glass, the optical axis of the substrate can be parallel to the ground direction of the substrate (i.e., as shown by the example). Figure 1 The dashed line indicates the direction parallel to the ground when all four wheels of the car are in contact with the ground, or the longitudinal direction of the car.

[0117] According to this structure, the direction of the passenger's line of sight or movement is matched with the optical axis direction of the substrate of the light modulation device, etc., so that optical inhomogeneities that may occur by applying anisotropic substrates can be improved or eliminated while utilizing the substrate.

[0118] There are no particular restrictions on the method of configuring such a car; it is usually done by installing a sunroof or glass on the car. However, this process allows the optical axis direction of the light modulation device to be taken into account during installation to achieve the above arrangement.

[0119] There are no particular limitations on other methods of realizing the automobile of this application, and known methods may be applied.

[0120] Invention Effects

[0121] This application can provide a light modulation device including an anisotropic plastic substrate and an automobile in which the light modulation device is applied to a sunroof and / or glass, and can provide an automobile that can eliminate or improve the disadvantages caused by the application of anisotropic plastic substrate while utilizing the light modulation device. Attached Figure Description

[0122] Figure 1 A diagram illustrating the appearance of an exemplary car.

[0123] Figures 2 to 4 This is a schematic diagram of an exemplary optical modulation device of this application.

[0124] Figures 5 to 16 This is a photograph showing the results of evaluating the uniformity of optical properties when a light modulation device is hypothetically applied to a vehicle's sunroof or glass. Detailed Implementation

[0125] 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.

[0126] Preparation Example 1. Fabrication of an optical modulation device (A)

[0127] A polyester film (SKC, highly stretched PET, in-plane phase difference (based on a wavelength of 550 nm): approximately 10,000 nm) with a thickness of approximately 145 μm was used as the first and second substrates, respectively, with an ITO (indium tin oxide) layer of a certain thickness deposited on each of their respective first surfaces. A horizontal photoalignment film (AMP21, LG Chem, norbornene series) was formed on each surface of the ITO layer of both the first and second substrates. During the formation of the alignment film on the surface of the ITO layer of the second substrate, spherical spacers with an average diameter (D50 diameter) of approximately 12 μm were dispersed in the alignment film material, thereby maintaining the thickness (cell gap) of the liquid crystal layer in the final product through the spherical spacers. The orientation of the photoalignment film was achieved by irradiation with linearly polarized ultraviolet light, and the orientation of the photoalignment film for the liquid crystal compound was approximately horizontal with the slow axis of the substrate. Subsequently, a liquid crystal composition (MDA-14-1235, manufactured by Merck) containing a dichroic dye is coated onto the alignment film of the second substrate, and a light modulation film layer is manufactured by aligning the surface of the first substrate on which the alignment film is formed with the coating layer of the liquid crystal composition facing each other. Then, an absorptive linear polarizing layer of PVA (polyvinyl alcohol) series is attached to one side of the light modulation film layer to manufacture a light modulation device. During attachment, the absorption axis of the linear polarizing layer is made horizontal with the slow axis of the substrate.

[0128] Example 1 and Comparative Example 1

[0129] The non-uniformity of light transmittance was evaluated by applying the light modulation device (A) of Preparation Example 1 to the sunroof of an automobile.

[0130] A surface light source was placed on the rear surface of the light modulation device, and the light modulation device was installed at the sunroof position of the vehicle, such that the slow axis of the base in the device was parallel to the width of the vehicle. Then, the non-uniformity was evaluated when the line of sight was moved left and right when viewed from the front (Test 1).

[0131] A surface light source was placed on the rear surface of the light modulation device, and the light modulation device was installed at the sunroof position of the vehicle, such that the slow axis of the base in the device was perpendicular to the width of the vehicle. Then, the non-uniformity was evaluated when the line of sight was moved left and right when viewed from the front (Test 2).

[0132] Test 1 above corresponds to Example 1, and Test 2 corresponds to Comparative Example 1.

[0133] Figures 5 to 7 These are the observations of the front, left, and right sides in Test 1 above. Figures 8 to 10 These are the observations of the front, left, and right sides in Test 2 above.

[0134] As shown in the figure, in test 1, the transmittance remains uniform even when the observer's line of sight moves, just like when viewed from the front. However, in test 2, transmittance deviations occur in different areas depending on the movement of the observer's line of sight, making it impossible to ensure optical uniformity.

[0135] Preparation Example 2. Fabrication of an optical modulation device (B)

[0136] A polyester film (SKC, highly stretched PET, in-plane phase difference (based on a wavelength of 550 nm): approximately 10,000 nm) with a thickness of approximately 145 μm was used as the first substrate, on which an ITO (indium tin oxide) layer of a certain thickness was deposited on the first surface. A pressure-sensitive adhesive layer was formed on the first surface of the first substrate. A silicone pressure-sensitive adhesive composition (Shinetsu, KR3700) was rod-coated and dried at approximately 150°C for 5 minutes to form a pressure-sensitive adhesive layer with a thickness of approximately 10 μm. As the second substrate, the same substrate as the first substrate was used. First, on the ITO layer of the second substrate, spacers forming regular hexagons (closed patterns) constituting a honeycomb structure with a pitch of approximately 350 μm, a height (cell gap) of approximately 6 μm, and a linewidth of approximately 10 μm were formed as honeycomb-type spacers, with an area ratio of approximately 9%. A vertical alignment film (5661LB3, Nissan) was formed on the formed spacers. The vertical alignment film was formed by rubbing it in one direction. Subsequently, a liquid crystal composition is coated onto the surface of a vertically aligned film on a second substrate, and a light modulation film is manufactured by bonding a pressure-sensitive adhesive layer of the first substrate to the coated surface layer of the liquid crystal composition so that they face each other. As the liquid crystal composition, a composition formulated by mixing a liquid crystal compound (MAT-19-1261, manufactured by Merck) with a chiral dopant (S811, manufactured by Merck) to achieve a pitch of approximately 20 μm is used. Subsequently, two PVA (polyvinyl alcohol) series absorptive linear polarizing layers are attached to both sides of the light modulation film to manufacture a light modulation device. During attachment, the absorption axis of the linear polarizing layer is made perpendicular or horizontal to the slow axis of the substrate, and the absorption axes between the two polarizing layers are made perpendicular to each other.

[0137] Example 2 and Comparative Example 2

[0138] The non-uniformity of light transmittance was evaluated by applying the light modulation device (A) of Preparation Example 2 to the sunroof of an automobile.

[0139] A surface light source was placed on the rear surface of the light modulation device, and the light modulation device was installed at the sunroof position of the vehicle, such that the slow axis of the base in the device was parallel to the width of the vehicle. Then, the non-uniformity was evaluated when the line of sight was moved left and right when viewed from the front (Test 3).

[0140] A surface light source was placed on the rear surface of the light modulation device, and the light modulation device was installed at the sunroof position of the vehicle, such that the slow axis of the base in the device was perpendicular to the width of the vehicle. Then, the non-uniformity was evaluated when the line of sight was moved left and right when viewed from the front (Test 4).

[0141] Test 3 above corresponds to Example 2, and Test 4 corresponds to Comparative Example 2.

[0142] Figures 11 to 13 These are the observations of the front, left, and right sides in test 3 above. Figures 14 to 16 These are the observations of the front, left, and right sides in test 4 above.

[0143] As shown in the figure, in test 3, the transmittance remains uniform even when the observer's line of sight moves, just like when viewed from the front. However, in test 4, transmittance deviations occur in different areas depending on the movement of the observer's line of sight, making it impossible to ensure optical uniformity.

Claims

1. A light modulation device configured to be included in a sunroof of a vehicle, the light modulation device comprising: Optical modulation film, The light modulation film layer includes: First anisotropic substrate and second anisotropic substrate; and Liquid crystal layer Each of the first anisotropic substrate and the second anisotropic substrate has a first surface. The first anisotropic substrate and the second anisotropic substrate are positioned such that the first surfaces of the first anisotropic substrate and the second anisotropic substrate face each other; The liquid crystal layer is located between the first surface of the first anisotropic substrate and the first surface of the second anisotropic substrate, and The slow axis of either the first anisotropic substrate or the second anisotropic substrate is formed parallel to the width direction of the vehicle. The light modulation device has a fastening device or fastening part, through which the light modulation device is mounted to the sunroof of the vehicle, or the light modulation device has the same shape as the sunroof. The fastening device or the fastening part, or the shape, is formed such that when the light modulation device is installed on the sunroof of the vehicle via the fastening device or the fastening part or according to the shape, the slow axis of the first anisotropic substrate or the second anisotropic substrate is arranged parallel to the width direction of the vehicle.

2. A light modulation device configured to be included in a front windshield, rear windshield, or side windshield of an automobile, the light modulation device comprising: Optical modulation film, The light modulation film layer includes: First anisotropic substrate and second anisotropic substrate; and Liquid crystal layer Each of the first anisotropic substrate and the second anisotropic substrate has a first surface. The first anisotropic substrate and the second anisotropic substrate are positioned such that the first surfaces of the first anisotropic substrate and the second anisotropic substrate face each other; The liquid crystal layer is located between the first surface of the first anisotropic substrate and the first surface of the second anisotropic substrate, and The slow axis of either the first anisotropic substrate or the second anisotropic substrate is formed parallel to the longitudinal direction of the vehicle. The light modulation device has a fastening device or fastening part, by means of which the light modulation device is mounted to the front windshield, rear windshield, or side windshield of the vehicle, or the light modulation device has the same shape as the front windshield, rear windshield, or side windshield, and The fastening device or the fastening part, or the shape, is formed such that when the light modulation device is mounted to the front, rear, or side glass of the vehicle via the fastening device or the fastening part or according to the shape, the slow axis of the first anisotropic substrate or the second anisotropic substrate is arranged parallel to the longitudinal direction of the vehicle.

3. The optical modulation apparatus according to claim 1 or 2, wherein the slow axes of the first anisotropic substrate and the second anisotropic substrate are parallel to each other.

4. The optical modulation apparatus according to claim 1 or 2, wherein the in-plane phase difference between the first anisotropic substrate and the second anisotropic substrate is 400 nm or greater.

5. The optical modulation apparatus according to claim 1 or 2, wherein a liquid crystal alignment film is present on each of the first surface of the first anisotropic substrate and the first surface of the second anisotropic substrate.

6. The optical modulation apparatus according to claim 1 or 2, wherein a pressure-sensitive adhesive layer or adhesive layer is provided on the first surface of the first anisotropic substrate, and a liquid crystal alignment film is provided on the first surface of the second anisotropic substrate.

7. The light modulation apparatus according to claim 1 or 2 further includes a polarizing layer disposed only on one side of the light modulation film layer, wherein the liquid crystal layer comprises a liquid crystal compound and a dichroic dye.

8. The optical modulation apparatus of claim 7, wherein the absorption axis of the polarizing layer is perpendicular or horizontal to the slow axis of the first anisotropic substrate or the second anisotropic substrate.

9. The optical modulation apparatus according to claim 1 or 2 further includes a polarizing layer disposed on both sides of the optical modulation film layer, wherein the liquid crystal layer comprises a liquid crystal compound and a chiral dopant.

10. The optical modulation apparatus of claim 9, wherein the absorption axis of the polarizing layer is perpendicular or horizontal to the slow axis of the first anisotropic substrate or the second anisotropic substrate.

11. A car, comprising: The light modulation device according to claim 1 in the skylight.

12. A car, comprising: The light modulation device according to claim 2 in the front glass, rear glass or side glass.

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