Optical modulation device

Abstract

The present application can provide an optical modulation device, an optical device including the same, or a manufacturing method, 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, 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. 10-2020-0095864, filed on July 31, 2020, and the disclosure of the Korean patent application is incorporated herein by reference.

[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 variety of applications.

[0004] To ensure that the optical modulation device exhibits the desired performance, controlling the alignment state of the liquid crystal compounds between the substrates is crucial. Therefore, when the optical modulation layer is a liquid crystal layer, liquid crystal alignment films are formed on both sides of the liquid crystal layer to control the alignment of the liquid crystal compounds.

[0005] Patent Document 1 discloses an optical modulation device having a structure in which a liquid crystal alignment film is formed on one side of a liquid crystal layer and an adhesive layer is formed on the other side in place of the liquid crystal alignment film.

[0006] It describes that, since the adhesive layer disclosed in Patent Document 1 has liquid crystal alignment force, the desired orientation of the liquid crystal compound is possible without applying a liquid crystal alignment film to one side of the liquid crystal layer.

[0007] The optical modulation device disclosed in Patent Document 1 has the following advantages: since an adhesive is applied to a substrate, the adhesive force between two substrates that are placed opposite each other can be maintained very well.

[0008] However, there is a problem: the adhesive layer disclosed in Patent Document 1 alone is not easy to maintain the orientation of the liquid crystal compound stably enough, and in particular, the orientation of the liquid crystal compound is destroyed under high temperature conditions, resulting in optical defects.

[0009] [Existing Technical Documents]

[0010] [Patent Literature]

[0011] (Patent Document 1) Korean Patent Publication No. 1987373

[0012] Public content

[0013] Technical issues

[0014] This application provides an optical modulation apparatus. The aim of this application is to provide an optical modulation apparatus that, while ensuring adhesion between substrates disposed opposite to each other by applying a pressure-sensitive adhesive layer or adhesive layer, simultaneously maintains the orientation of a liquid crystal compound, and in particular, achieves the desired orientation state of the liquid crystal compound even at high temperatures.

[0015] Technical solution

[0016] In this specification, the terms "perpendicular, parallel, orthogonal, or horizontal" that define angles and angle values ​​mean "substantially perpendicular, substantially parallel, substantially orthogonal, or substantially horizontal" and the basic angle value within a range that does not impair the desired effect. Perpendicular, parallel, orthogonal, or horizontal, and the range of values, include errors such as manufacturing tolerances or deviations (variations). For example, each of the above may 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.

[0017] In this specification, when the measurement temperature affects the relevant physical properties, unless otherwise stated, the physical properties are those measured at room temperature. The term room temperature means temperature under conditions without special 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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 relative 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.

[0026] 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.

[0027] In one example, the optical modulation device of this application can be designed to switch between any state selected from a transparent mode state and a black mode state and another state. If necessary, a third different state or more states in addition to the states mentioned above can also be implemented.

[0028] The switching of the optical modulation device can be controlled based on whether an external signal, such as an electrical signal like voltage, is applied. For example, in the absence of an external signal, 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 even a third different mode state can be achieved.

[0029] The optical modulation device of this application may include two substrates disposed opposite to each other and an optical modulation layer positioned between the substrates. Figure 2 This is a diagram illustrating an example of the structure. As shown, the optical modulation device includes a first substrate 100 and a second substrate 200 disposed opposite to each other. The first substrate and the second substrate may each have a first surface and a second surface. Here, the first surface may be a principal surface of the substrate, and the second surface may refer to the principal surface opposite to it.

[0030] 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 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 the second substrate 200. The type of light modulation layer is not particularly limited, and a liquid crystal layer can generally be used as the light modulation layer. 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, a pressure-sensitive adhesive layer or adhesive layer instead of a liquid crystal alignment film is formed on the first substrate 100, and the liquid crystal alignment film is formed only on the second substrate 200. This allows for the attainment of an orientation state of the liquid crystal compound that is highly useful in specific applications (e.g., smart windows or eye-wearing devices). In this case, no liquid crystal alignment film is formed on the first substrate. Furthermore, although not shown in the figure, in either the first substrate or the second substrate of the optical modulation device, 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.

[0031] As a substrate, known substrate materials can be used without particular restriction. For example, inorganic substrates such as glass substrates, crystalline 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; it can be selected within an appropriate range.

[0032] In one instance, an optically anisotropic film can also be used as the substrate. Films with such optical anisotropy are generally also anisotropic in terms of mechanical properties, and by utilizing such anisotropy, optical modulation devices with excellent durability and other properties can be provided.

[0033] In one instance, the in-plane phase difference of the anisotropic film can be approximately 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 formula A. 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.

[0034] There are no particular restrictions on the specific type of film that can be applied 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. Examples of polymer films include, for instance, polyolefin films, such as polyethylene or polypropylene films; cycloolefin polymer (COP) films, such as polynorbornene films; polyvinyl chloride films; polyacrylonitrile films; polysulfone films; polyacrylate films; PVA (polyvinyl 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.

[0035] In one example, a polyester film, such as a PET (polyethylene terephthalate) film, can be used as the film. That is, films exhibiting in-plane phase differences within the aforementioned range are known in industry, and in the case of polymer films, such films exhibit asymmetry even in mechanical properties and large optical anisotropy through stretching or other processes during manufacturing. A representative example of such a retardation film known in industry is a stretched polyester film, such as a stretched PET (polyethylene terephthalate) film.

[0036] 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.

[0037] Furthermore, the in-plane phase difference is a physical quantity based on the following formula A.

[0038] [Formula A]

[0039] Rin = d × (nx - ny)

[0040] In formula A, Rin is the in-plane phase difference, nx is the refractive index of the film along the slow axis, ny is the refractive index of the film along the fast axis, and d is the thickness of the film. Here, the meanings of the slow axis and fast axis are known in industry.

[0041] When an anisotropic membrane is applied to both a first substrate and a second substrate, the substrates can be configured such that the slow axis of the first substrate and the slow axis of the second substrate are parallel or perpendicular to each other.

[0042] An optical modulation layer existing between substrates is a functional layer capable of altering 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 may be referred to as an active optical modulation layer.

[0043] In this specification, an external signal can refer to an external factor that 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), such as an electrical signal like voltage. Therefore, a state without any external signal can mean a state where no electrical signal is applied from the outside. A state without any external signal can also be referred to as the initial state.

[0044] 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.

[0045] 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, and for example, 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, is also a type of liquid crystal layer defined in this specification. The liquid crystal layer may contain a liquid crystal compound formed such that its 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 its 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 its orientation direction can be changed by applying an external signal, or a compound that exists in a non-polymerized and non-crosslinked state even if it has polymerizable or crosslinkable groups.

[0046] 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 horizontal dielectric constant (ε / / ) and the vertical dielectric constant (ε) of the liquid crystal. ⊥ The difference between (ε / / -ε) ⊥ 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. ㅗ The dielectric constant is the value measured along the direction of the electric field when a voltage is applied such that the direction of the liquid crystal's pointer and the direction of the electric field generated by the applied voltage are substantially perpendicular.

[0047] For example, the refractive index anisotropy (Δn) of a 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 around 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 0.1 or less. The refractive index anisotropy of the liquid crystal layer is selected according to the purpose and is not limited thereto.

[0048] 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.

[0049] The liquid crystal layer of this application can be designed (formed) to achieve at least the above-mentioned twisted orientation. Twisted orientation refers to the state in which the liquid crystal compound in the liquid crystal layer is 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 compound in the liquid crystal layer is horizontally oriented, vertically oriented, tilted oriented, or jet-oriented. In addition, 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.

[0050] In one example, the liquid crystal layer can be designed (formed) to be able to switch between at least a vertical alignment state and a twisted alignment state. For example, it can realize either of the two states in an initial state, or it can switch to the other state when an external signal (e.g., an electrical signal such as voltage) is applied. In one example, the vertical alignment state can be realized in the initial state.

[0051] The optical modulation device of this application can be designed to stably maintain the above-mentioned orientation state of the liquid crystal layer (in particular, the vertical orientation state) even at high temperatures.

[0052] For example, an optical modulation device including the following can satisfy the following formula 1: a first substrate and a second substrate, each having a first surface and a second surface respectively and disposed opposite to each other such that the first surface of the first substrate and the first surface of the second substrate face each other; and a liquid crystal layer existing between the first substrate and the second substrate.

[0053] [Formula 1]

[0054] T2≤3×T1

[0055] In Formula 1, T1 is the initial transmittance measured after the liquid crystal layer is vertically aligned and placed between orthogonal polarizers, and T2 is the transmittance measured after the liquid crystal layer exhibiting transmittance T1 is held at 100°C for 5 minutes in a vertically aligned state and then placed between orthogonal polarizers.

[0056] Here, T1 and T2 are in percentage (%). Furthermore, the initial transmittance T1 was measured at room temperature, and the transmittance T2 was measured with the temperature held at 100°C for 5 minutes and then left unchanged at 100°C.

[0057] In addition, the transmittance T1 and transmittance T2 were measured at visible light wavelengths (380 nm to 770 nm).

[0058] Figure 1 This is a diagram illustrating the process of determining T1 and T2.

[0059] like Figure 1 As shown, transmittance T1 and transmittance T2 can be measured with the liquid crystal layer or light modulation device 200 positioned between two orthogonal polarizers (101, 102). At this time, as... Figure 1 As shown, transmittance is the ratio of light incident from either polarizer 101 onto the other polarizer 102 of the two orthogonal polarizers (101, 102) (along the direction of light transmission). Figure 1 The transmittance is measured after the arrow in the image (in the direction of the arrow).

[0060] An orthogonal polarizer refers to a polarizer in which the light absorption axes of the two polarizers are perpendicular to each other. Typically, when the transmittance is measured with the light absorption axis of one polarizer fixed and the light absorption axis of the other polarizer rotated relative to its light absorption axis, the point where the lowest transmittance occurs is considered to be the point where the light absorption axes of the two polarizers are perpendicular to each other.

[0061] When the liquid crystal layer is in a vertically aligned state, such as Figure 1 The device is positioned between two orthogonal polarizers, and if transmittance is measured, the measured transmittance is low. Therefore, T1 is a very low value. When the vertical alignment characteristics of the liquid crystal layer are damaged or deteriorated while it is held at high temperature for a certain period of time in a vertically aligned state (5 minutes at 100°C), the measured T2 is higher than T1. In the measurement of T1 and T2 above, when the first and / or second substrates of the optical modulation device are anisotropic substrates, the slow axis of the relevant substrates is arranged parallel to the light absorption axis of either polarizer.

[0062] However, in the optical modulation apparatus of this application, the alignment characteristics (especially the vertical alignment characteristics) of the liquid crystal layer can be stably maintained even at high temperatures, allowing T2 to be 3 times or less than T1 (3 × T1 or less). In another example, T2 may also be approximately 2.5 times or less than T1 (2.5 × T1 or less), 2 times or less than T1 (2 × T1 or less), 1.5 times or less than T1 (1.5 × T1 or less), or 1 time or less than T1 (T1 or less). There is no particular limitation on the lower limit of T2, and in one example, it may be 0.5 times or more than T1 (0.5 × T1 or more), 0.7 times or more than T1 (0.7 × T1 or more), or 0.9 times or more than T1 (0.9 × T1 or more). In one example, T1 and T2 may be substantially the same.

[0063] There is no particular limitation on the specific value of T2, but in one instance, it can be around 2% or less. In another instance, T2 can be around 1.8% or less, 1.6% or less, 1.4% or less, 1.2% or less, 1% or less, 0.8% or less, 0.6% or less, 0.4% or less, or 0.2% or less. There is no lower limit to T2, and for example, T2 can be 0% or greater.

[0064] The methods for measuring T1 and T2 are described in detail in the embodiments.

[0065] The light modulation layer of the liquid crystal layer mainly contains liquid crystal compounds, and may also contain other components if necessary.

[0066] 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.

[0067] 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. 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 example, compounds having one or two or more asymmetric carbons; compounds having asymmetric sites on heteroatoms, such as chiral amines or chiral sulfoxides; or compounds having axial asymmetry and optically active sites, such as cumulative polyenes or binatol. Chiral dopants can be, for example, low molecular weight compounds having 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 from Merck Co., Ltd. or BASF's LC756.

[0068] There is no particular limitation on the ratio of chiral dopants, but chiral dopants can be added so that the ratio (d / p) of the thickness (d, inter-cell gap) of the light modulation layer to the pitch (twisted orientation pitch) (p) of the helical structure of the liquid crystal compound generated by the addition of chiral dopants can satisfy the K value described below.

[0069] The pitch (p) of a so-called twisted-oriented optical modulation layer (liquid crystal layer) with chiral dopant can be measured using a wedge cell measurement method, and it 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 formula 100 / (HTP (helical twisting power) × pitch (nm)), which can be chosen by considering the desired pitch (p) at an appropriate ratio.

[0070] The liquid crystal layer can be designed such that the ratio (d, unit) of the thickness of the light modulation layer (liquid crystal layer) to the pitch (p) of the twisted orientation (d / p) is less than 1. In another example, this ratio (d / 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, 0.35 or less, 0.3 or less, 0.25 or less, or 0.2 or less, or it can also be 0.1 or more, 0.15 or more, 0.2 or more, 0.25 or more, 0.3 or more, 0.35 or more, 0.4 or more, 0.45 or more, or approximately 0.5 or more.

[0071] The liquid crystal layer can be designed such that the pitch (p) of the twisted orientation is in the range of 1 μm to 100 μm. In another example, the ratio can be 2μm or larger, 3μm or larger, 4μm or larger, 5μm or larger, 6μm or larger, 7μm or larger, 8μm or larger, 9μm or larger, 10μm or larger, 11μm or larger, 12μm or larger, 13μm or larger, 14μm or larger, 15μm or larger, 16μm or larger, 17μm or larger, 18μm or larger, 19μm or larger, or 19.5μm or larger, or it can also be 95μm or smaller, 90μm or smaller, 85μm or smaller, 80μm or smaller, 75μm or smaller, 70μm or smaller, 65μm or smaller, 60μm or smaller, 55μm or smaller, 50μm or smaller, 45μm or smaller, 40μm or smaller, 35μm or smaller, 30μm or smaller, or around 25μm or smaller.

[0072] The thickness (d, cell gap) of the liquid crystal layer can range from 0.5 μm to 50 μm. In another example, the thickness (d, 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, 4 μm or greater, 4.5 μm or greater, 5 μm or greater, 5.5 μm or greater, 6 μm or greater, 6.5 μm or greater, 7 μm or greater, 7.5 μm or greater, 8 μm or greater, 8.5 μm or greater, 9 μm or greater, 9.5 μm or greater, or... 10μm or larger, or possibly 48μm or smaller, 46μm or smaller, 44μm or smaller, 42μm or smaller, 38μm or smaller, 36μm or smaller, 34μm or smaller, 32μm or smaller, 30μm or smaller, 28μm or smaller, 26μm or smaller, 24μm or smaller, 22μm or smaller, 20μm or smaller, 18μm or smaller, 16μm or smaller, 14μm or smaller, 12μm or smaller, or around 10μm or smaller.

[0073] This design provides an optical modulation device that can more effectively achieve the objectives of this application.

[0074] Other necessary additional components (e.g., dichroic dyes) may also be included in the light modulation layer (liquid crystal layer).

[0075] When an adhesive layer or pressure-sensitive adhesive layer is formed on the first surface of a first substrate in an optical modulation device, the type of pressure-sensitive adhesive layer or adhesive layer is not particularly limited. However, silicone-based pressure-sensitive adhesive layers or silicone-based adhesive layers can be applied in respect of the fact that they can be easily blended with a compound of Formula 1 (hereinafter referred to as a silicon compound) to achieve the desired effect. For example, various types of industrially known silicone-based pressure-sensitive adhesives or silicone-based adhesives exist as so-called OCA (Optically Transparent Adhesive) or OCR (Optically Transparent Resin), and these pressure-sensitive adhesives or adhesives can be combined with liquid crystal alignment films in a state containing a silicon compound described below to induce a suitable orientation of the liquid crystal compound.

[0076] That is, the specific surface properties of silicone-based pressure-sensitive adhesives or binders containing silicon compounds can be combined with liquid crystal alignment films (especially vertical alignment films) to induce an orientation state of the liquid crystal compound suitable for the purpose.

[0077] 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, and, for example, a thermosetting silicone composition or a UV-curable silicone composition can be used.

[0078] 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.

[0079] (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 in addition to the alkenyl groups described above may include alkyl, such as methyl, ethyl, propyl, butyl, pentenyl, hexenyl, or heptenyl; 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.

[0080] (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.

[0081] (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, 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.

[0082] 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, the types of substituents that may be included in addition to the hydrogen atoms bonded to silicon are not particularly limited; they may 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 thereto.

[0083] (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 generally used, but are not limited to this.

[0084] (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.

[0085] (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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] (a) The siloxane polymer can be, for example, a compound represented by formula I.

[0090] [Formula I]

[0091] R 1 a R 2 b SiO c (OR 3 ) d

[0092] In equation I, 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.

[0093] In the definition of Formula I, 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 groups.

[0094] Under the constraints of Equation I, 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.

[0095] In the polymer of formula I, branched or tertiary crosslinked siloxane polymers may 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 dealcoholization reaction.

[0096] (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.

[0097] As (a) a siloxane polymer, commercially available organosiloxane polymers such as Shin-EtsuSilicone's X40-9220 or X40-9225, or GE Toray Silicone's XR31-B1410, XR31-B0270, or XR31-B2733 can be used.

[0098] As a condensable curable silicone composition, (b) a hydroxyl-containing siloxane polymer may be used, for example, a compound represented by formula II.

[0099] [Formula II]

[0100]

[0101] In Equation II, R 4 and R 5 Each independently represents a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, wherein when there are multiple R... 4 and R 5 They can be the same or different from each other, and n represents an integer from 5 to 2,000.

[0102] In the definition of Formula II, the specific type of monovalent hydrocarbon group may include, for example, the same hydrocarbon group as in Formula I above.

[0103] (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.

[0104] 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.

[0105] 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.

[0106] A specific silicon compound is included in the silicone pressure-sensitive adhesive layer or adhesive layer. As the silicon compound, a compound having three or more substituents of Formula 1 can be used. Such a compound can effectively form and maintain the orientation of the liquid crystal compound by controlling the surface properties of the silicone pressure-sensitive adhesive layer or adhesive layer, and allows the orientation to be stably maintained even under high temperature conditions.

[0107] [Formula 1]

[0108]

[0109] In Formula 1, R1 to R3 are each independently a hydrogen atom or an alkyl group, but at least two of R1 to R3 can be alkyl groups. Additionally, in Formula 1, * indicates that the corresponding site is connected.

[0110] In Formula 1, the alkyl group can be a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms. Such an alkyl group can optionally be substituted with one or more substituents, or can be an unsubstituted alkyl group.

[0111] In one instance, the alkyl group of Formula 1 above can be a linear or branched alkyl group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms, or it can be a linear alkyl group.

[0112] In one example, any one of R1 to R3 in Formula 1 may be a hydrogen atom, and the other two may be alkyl groups. Furthermore, in one example, any one of R1 to R3 in Formula 1 may be a hydrogen atom, and the other two may be linear or branched alkyl groups having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms, or may be linear alkyl groups, and such alkyl groups may optionally be substituted with one or more substituents, or may be unsubstituted alkyl groups.

[0113] Compounds having three or more of the above formula 1 substituents may contain 3 to 10, 3 to 9, 3 to 8, 3 to 7, 3 to 6, 3 to 5, or 3 to 4 of the above formula 1 substituents.

[0114] Various types of compounds containing substituents of Formula 1 can be used as this compound, and one example is a compound represented by Formula 2 below.

[0115] [Equation 2]

[0116]

[0117] In Formula 2, R4 to R7 are each independently hydrogen, alkyl or Formula 1 substituents, but three or more of R4 to R7 are Formula 1 substituents.

[0118] In Formula 2, the alkyl group can be a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms. Such an alkyl group can optionally be substituted with one or more substituents, or can be an unsubstituted alkyl group.

[0119] In one instance, the alkyl group of Formula 2 above can be a linear or branched alkyl group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms, or it can be a linear alkyl group.

[0120] There is no particular limitation on the ratio of the silicone pressure-sensitive adhesive layer or the compound having three or more substituents of Formula 1 (silicone compound) in the adhesive layer, but the ratio can be adjusted to the range of 1 wt% to 50 wt%. In another example, the ratio can be 2 wt% or more, 3 wt% or more, 4 wt% or more, 5 wt% or more, 6 wt% or more, 7 wt% or more, 8 wt% or more, 9 wt% or more, 10 wt% or more, 11 wt% or more, 12 wt% or more, 13 wt% or more, 14 wt% or more, or 15 wt% or more, or it can be 49 wt% or less, 48 ​​wt% or less, 47 wt% or less, 46 wt% or less, 45 wt% or less, 44 wt% or less, 43 wt% or less, 42 wt% or less, 41 wt% or less, 30 wt% or less, 39 wt% or less, 38 wt% or less, 37 wt% or less, or 37 wt% or less. % or less, 36 wt% or less, 35 wt% or less, 34 wt% or less, 33 wt% or less, 32 wt% or less, 31 wt% or less, 30 wt% or less, 29 wt% or less, 28 wt% or less, 27 wt% or less, 26 wt% or less, 25 wt% or less, 24 wt% or less, 23 wt% or less, 22 wt% or less, 21 wt% or less, 20 wt% or less, 19 wt% or less, 18 wt% or less, 17 wt% or less, 16 wt% or less, 15 wt% or less, 14 wt% or less, 13 wt% or less, 12 wt% or less, 11 wt% or less, or about 10 wt% or less. Within the above ratio range, the desired orientation characteristics and high-temperature stability of the liquid crystal compound can be more effectively ensured.

[0121] In one instance, a compound (silicon compound) having substituents of Formula 1 above can be selected and applied such that the K value according to Formula 1 below is 2 μm or greater.

[0122] [Formula 1]

[0123] K = A × B × D

[0124] In Formula 1, A is a value determined by Formula 2 below, B is the number of Formula 1 substituents contained in a compound (silicon compound) having three or more Formula 1 substituents, and D is the thickness of the silicone pressure-sensitive adhesive layer or adhesive layer. Here, the unit of the thickness (D) of the silicone pressure-sensitive adhesive layer or adhesive layer is μm.

[0125] [Formula 2]

[0126] A = S / (S + O)

[0127] In Formula 2, S is the weight of the silicone pressure-sensitive adhesive layer or the compound (silicone compound) containing three or more substituents of Formula 1 contained in the adhesive layer, and O is the weight of the pressure-sensitive adhesive layer or the adhesive layer excluding the compound having three or more substituents of Formula 1 above. Various units may be used if the units of weight for S and O are the same, but g is generally used.

[0128] In another example, the K value in Formula 1 above can be 2.5 or greater, or 3 or greater, or it can be around 10 or less, 9 or less, 8 or less, 7 or less, 6 or less, 5 or less, or 4.5 or less. Within this range, the desired orientation and high-temperature orientation stability of the liquid crystal compound can be more stably ensured.

[0129] In Formula 1, A can be, for example, in the range of 0.01 to 0.5. In another instance, A 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, 0.09 or greater, 0.10 or greater, 0.11 or greater, 0.12 or greater, 0.13 or greater, 0.14 or greater, or 0.15 or greater, or it can be 0.49 or less, 0.48 or less, 0.47 or less, 0.46 or less, 0.45 or less, 0.44 or less, 0.43 or less, 0.42 or less, 0.41 or less, 0.39 or less, 0.38 or less, or 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, 0.30 or less, 0.29 or less, 0.28 or less, 0.27 or less, 0.26 or less, 0.25 or less, 0.24 or less, 0.23 or less, 0.22 or less, 0.21 or less, 0.20 or less, 0.19 or less, 0.18 or less, 0.17 or less, 0.16 or less, 0.15 or less, 0.14 or less, 0.13 or less, 0.12 or less, 0.11 or less, or approximately 0.10 or less. Within the above ratio range, the desired alignment characteristics and high-temperature stability of the liquid crystal compound can be more effectively ensured. Within this range, the desired alignment and high-temperature alignment stability of the liquid crystal compound can be more stably ensured.

[0130] In Formula 1, D, i.e., the thickness of the silicone pressure-sensitive adhesive layer or adhesive layer, can be, for example, in the range of 0.5 μm to 50 μm. In another example, the thickness (d, inter-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, 4 μm or greater, 4.5 μm or greater, 5 μm or greater, 5.5 μm or greater, 6 μm or greater, 6.5 μm or greater, 7 μm or greater, 7.5 μm or greater, 8 μm or greater, 8.5 μm or greater, 9 μm or greater, 9.5 μm or greater, 1... The micrometer size can be 0 μm or larger, or it can be approximately 48 μm or smaller, 46 μm or smaller, 44 μm or smaller, 42 μm or smaller, 38 μm or smaller, 36 μm or smaller, 34 μm or smaller, 32 μm or smaller, 30 μm or smaller, 28 μm or smaller, 26 μm or smaller, 24 μm or smaller, 22 μm or smaller, 20 μm or smaller, 18 μm or smaller, 16 μm or smaller, 14 μm or smaller, 12 μm or smaller, or 10 μm or smaller. Within this range, the desired orientation and high-temperature orientation stability of the liquid crystal compound can be more stably ensured.

[0131] When the pressure-sensitive adhesive layer or adhesive layer as described above is formed on the first surface of the first substrate, a liquid crystal alignment film may not be formed on the first substrate.

[0132] There are no particular limitations on the type of liquid crystal alignment film that can be formed on the first surface of the second substrate in the optical modulation device. Known vertical alignment films, horizontal alignment films, or other alignment films can be used 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 used. In one example, a vertical alignment film can be used as the alignment film. For example, a combination of a vertical alignment film and a pressure-sensitive adhesive layer or adhesive layer as described above can induce an alignment state of the liquid crystal compound suitable for various applications.

[0133] The initial orientation of the liquid crystal compound in the liquid crystal layer, which is the light modulation layer, formed by the liquid crystal alignment film and / or the pressure-sensitive adhesive layer, or the adhesive layer and the liquid crystal alignment film, 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. Initial orientation refers to the orientation of the liquid crystal compound in the aforementioned initial states.

[0134] The meanings of horizontal orientation, tilted orientation, vertical orientation, or jet orientation are as 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.

[0135] 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.

[0136] 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.

[0137] The in-plane phase difference is obtained according to the above formula A. In this case, nx, ny, and d in formula A are the refractive index of the slow axis, the refractive index of the fast axis, and the thickness of the light modulation layer, respectively.

[0138] The optical modulation apparatus 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, or combinations of both or more of these commonly used spacers, may be applied. In a suitable example, partition wall spacers may be used, particularly partition wall spacers 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, particularly regular hexagons, are also called so-called honeycomb 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 shape formed by the spacers is of a honeycomb or quadrilateral type. The honeycomb type is typically a combination of regular hexagons, and in the case of the quadrilateral type, squares, rectangles, or combinations of squares and rectangles, etc., may exist. Considering the adhesive force between the first substrate and the second substrate, a partition wall spacer can be used as a spacer, but is not limited to this.

[0139] 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. For instance, if the spacers are 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 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 pitch.

[0140] When the partition wall spacers form a closed shape, for example, the area of ​​the closed shape (i.e., the area of ​​a hexagon or quadrilateral) can be, for example, about 1 mm. 2 Up to 200mm 2 Within a certain range. When multiple closed figures are formed by separating walls and the closed figures have different areas, the area is the arithmetic mean.

[0141] 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.

[0142] 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, the combination with the spacer wall can provide excellent adhesion between the substrates.

[0143] As a component for applying external signals to the optical modulation layer, electrode layers can be formed on each substrate of the optical modulation device. 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 layer, or adhesive layer). Figure 2 Between 100 and 1001 in the middle) and / or between the first surface in the second substrate and the liquid crystal 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.

[0144] 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.

[0145] The optical modulation device may include other additional components as needed, in addition to the main optical modulation device. That is, depending on the driving mode, even in the case of a single optical modulation device, the realization of the above-mentioned transparent, black, high reflective and / or low reflective modes and the switching between them are possible, but additional components may be included to facilitate the realization or switching of these modes.

[0146] For example, the device may also include a polarizing layer (passive polarizing layer) disposed on one or both sides of the optical modulation device. 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 device, and Figure 4 Is Figure 2 In the structure, the polarizing layer 400 is disposed on both sides of the optical modulation device. 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.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] 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 device. In this case, the angle formed by the transmission axis of the polarizing layers disposed on both sides can be in the range of 85 degrees to 95 degrees, or approximately perpendicular.

[0151] 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 a dichroic dye, which is another component, is blended into the liquid crystal layer.

[0152] In addition to the above-mentioned structures, the optical modulation device may also include other necessary structures.

[0153] For example, the 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.

[0154] [Formula 3]

[0155] nz<ny

[0156] In Formula 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.

[0157] An optically anisotropic film that satisfies the relationship in Formula 3 above is a film that exhibits so-called negative C-plate characteristics.

[0158] Based on a wavelength of 550 nm, the thickness direction phase difference of such an optically anisotropic film can, for example, be in the range of less than 0 nm to -600 nm or greater. The optically anisotropic film can also exist in one layer or two or more layers of an optical device, and when the optically anisotropic film exists in one layer, the thickness direction phase difference is the thickness direction phase difference of that one layer, and when it exists in two or more layers, it is the sum of the thickness direction phase differences of all the films.

[0159] Furthermore, the phase difference in the thickness direction is a physical quantity determined by the following formula 4.

[0160] [Formula 4]

[0161] Rth = d × (nz - ny)

[0162] 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 industry.

[0163] As an optical anisotropic film, films that satisfy Formula 3 above and are known as retardation films can be applied, and such films, for example, stretched polymer films or liquid crystal films, are well known in industry.

[0164] An optically anisotropic film can exist on a first substrate and / or a second substrate, and it 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 adhesive layer (such as a liquid crystal alignment film) is formed on the first surface, it can be formed between the first substrate and / or the second substrate and the liquid crystal alignment film; and when an electrode layer is formed on the first surface, it can also be formed between the first substrate and / or the second substrate and the electrode layer.

[0165] In addition to the above-described structures, the optical modulation device may include other structures if necessary. 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 formed on the first surface of the first substrate.

[0166] 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.

[0167] Such optical devices can be used in a variety of applications, including, for example, eye-wearing devices such as sunglasses, eye-wearing devices for AR (Augmented Reality) or VR (Virtual Reality), exterior walls of buildings, or sunroofs for vehicles. This application can provide windows including light modulation devices and sunroofs including light modulation devices.

[0168] Beneficial effects

[0169] This application provides an optical modulation device, its optical device, or a method of manufacturing 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, its optical device, or a method of manufacturing 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

[0170] Figure 1 The diagram illustrates the process of measuring transmittance T1 and T2.

[0171] Figures 2 to 4 This is a schematic diagram of an exemplary optical modulation device of this application.

[0172] Figure 5 This is the result of evaluating the high-temperature orientation stability of the optical modulation device in Example 1.

[0173] Figure 6 This is the result of evaluating the high-temperature orientation stability of the optical modulation device in Comparative Example 1. Detailed Implementation

[0174] 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.

[0175] 1. Measurement of transmittance T1 and T2

[0176] The transmittance T1 and T2 of the optical modulation device manufactured in the embodiment or comparative example are measured. Here, the optical modulation device used for measurement is the device prior to attaching the PVA (polyvinyl alcohol) polarizing layer to the second surface of the first substrate and the second surface of the second substrate. Furthermore, the optical modulation device of the embodiment or comparative example is configured such that the initial orientation is vertical, so that the transmittance T1 and T2 are measured without applying a separate power supply.

[0177] In the Olympus BX51 polarizing microscope, the absorption axes of the built-in polarizers are set orthogonal to each other, and after turning on the metal halide light source of the microscope, a Linkam LTS420 hot stage is mounted on the microscope stage. The sample (light modulation device) is placed on the Linkam LTS420 hot stage. At this time, the slow axis of the substrate of the light modulation device is parallel to the absorption axis of one of the polarizers built into the BX51 polarizing microscope. In this state, the transmittance T1 is measured. The transmittance is measured by mounting a StellarNet Blue-Wave UVN spectrometer on the microscope, and the measurement wavelength is set in the visible light wavelength range (approximately 380 nm to 770 nm).

[0178] After measuring the transmittance T1, the temperature of the Linkam LTS420 hot stage was set to 100°C and maintained at 100°C for 5 minutes.

[0179] After being held at high temperature, transmittance T2 was measured in the same manner as transmittance T1. However, immediately after being held at 100°C for 5 minutes using a Linkam LTS420 hot stage, transmittance T2 was measured while maintaining its original temperature.

[0180] 2. Phase difference assessment

[0181] 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 formula A, and the maximum peak (T) in the sinusoidal waveform... 最大 The condition satisfies the following formula B. In formula A, λ 最大 In the case of [missing information], since T in formula A is the same as T in formula B, the formulas are expanded. Since the formulas are also expanded for n+1, n+2, and n+3, the formulas for n and n+1 are rearranged to eliminate R, and n is rearranged into formulas for λn and λn+1, thus deriving the following formula C. Since n and λ can be known based on the fact that T in formula A is the same as T in formula B, R for each of λn, λn+1, λn+2, and λn+3 is obtained. A linear trend line for the R values ​​based on the wavelengths of the four points is obtained, and the R value for formula 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 in the function is replaced by 550nm is the Rin value for light with a wavelength of 550nm.

[0182] [Formula A]

[0183] T = sin 2 [(2πR / λ)]

[0184] [Formula B]

[0185] T = sin 2 [((2n+1)π / 2)]

[0186] [Formula C]

[0187] n=(λn-3λn+1》 / (2λn+1+1-2λn)

[0188] In the above, R represents the in-plane delay (Rin), λ represents the wavelength, and n represents the nodal degree of the sine wave.

[0189] 3. Thickness Assessment

[0190] The thicknesses of the liquid crystal layer and the silicone pressure-sensitive adhesive layer were determined using a measuring device (F20, manufactured by Filmetric). Here, the thickness of the liquid crystal layer is the cell gap determined by the height of the spacers.

[0191] Example 1

[0192] Manufacturing of optical modulation devices

[0193] As the first substrate for the optical modulation device, a PET (polyethylene terephthalate) film (SKC, a high-strength PET product) with a thickness of approximately 145 μm on one side, wherein an ITO (indium tin oxide) electrode layer is deposited. The in-plane phase difference (550 nm) of the PET film is approximately 10,000 nm. An organosilicon pressure-sensitive adhesive layer is formed on the surface of the ITO electrode layer of the PET film.

[0194] A pressure-sensitive adhesive solution was prepared by adding a catalyst (Shin-Etsu, CAT-PL-56) and a compound of formula A to a silicone pressure-sensitive adhesive precursor solution (manufactured by Shin-Etsu Chemical, KR-3700) in which the silicone pressure-sensitive adhesive precursor was dissolved in toluene as a solvent at a solid concentration of about 60% by weight. The solution was then coated onto an ITO layer and held at approximately 150°C for 5 minutes to form a silicone pressure-sensitive adhesive layer with a thickness of approximately 8 μm. Here, the weight ratio of the silicone pressure-sensitive adhesive precursor, catalyst, and compound of formula A (precursor (excluding solvent): catalyst: compound of formula A) was 60:0.5:6.7.

[0195] Since the weight ratio of the silicone pressure-sensitive adhesive precursor (manufactured by Shin-Etsu Chemical, KR-3700), the catalyst (Shin-Etsu, CAT-PL-56), and the compound of formula A in the pressure-sensitive adhesive solution is approximately 60:0.5:6.7, the value of A in the formed pressure-sensitive adhesive layer is approximately 0.1 according to the following formula 2.

[0196] As the second substrate, a PET (polyethylene terephthalate) film (manufactured by Toyobo, SRF product) with a thickness of approximately 80 μm on which an ITO (indium tin oxide) layer is deposited on the first surface is used. The in-plane phase difference (550 nm) of the PET film is approximately 9,000. On the ITO layer of the PET film, spacers with a pitch of approximately 350 μm, a linewidth of approximately 10 μm, and a height of approximately 6 μm are formed as quadrilateral spacers at an area ratio of approximately 9% (the ratio of the area occupied by the spacers to the total substrate area). A vertical alignment film (5661LB3, Nissan) is formed on the spacers. The alignment film material (5661LB3, Nissan) is diluted in a solvent to a solids content of approximately 2.2% by weight, coated with #2 rods, and then held at 100°C for approximately 10 minutes to form the alignment film. The vertical alignment film is formed by rubbing it in one direction. Make the friction direction perpendicular to the slow axis direction of the second base.

[0197] Subsequently, a liquid crystal composition is coated on the surface of the vertical alignment film of the second substrate, and pressure-sensitive adhesive layers of the first substrate are laminated to form a coating surface facing the liquid crystal composition. At this time, the positions of the slow axis of the first substrate and the slow axis of the second substrate are adjusted so that the axes are parallel to each other.

[0198] Here, a composition comprising a liquid crystal compound (Merck, MAT-19-1205) 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) is about 20 μm.

[0199] Subsequently, a PVA (polyvinyl alcohol) polarizing layer is attached to the second surface of each of the first and second substrates. At this time, the absorption axis of the PVA polarizing layer attached to the second substrate is made perpendicular to the slow axis of the second substrate, and the absorption axis of the PVA polarizing layer attached to the first substrate is made parallel to the slow axis of the first substrate.

[0200] [Formula 2]

[0201] A = S / (S + O)

[0202] In Formula 2, S is the weight of the silicone compound in the pressure-sensitive adhesive layer (in the case of Example 1, the compound of Formula A), and O is the weight of the pressure-sensitive adhesive layer excluding the silicone compound.

[0203] [Formula A]

[0204]

[0205] Example 2

[0206] The optical modulation device was manufactured in the same manner as in Example 1, except that the silicone pressure-sensitive adhesive layer was formed to have a thickness of about 10 μm.

[0207] Example 3

[0208] The optical modulation device was manufactured in the same manner as in Example 1, except that the ratio of compound A was adjusted so that the value of A in Formula 2 was about 0.125, and the thickness of the silicone adhesive layer was about 6 μm.

[0209] Example 4

[0210] The optical modulation device was manufactured in the same manner as in Example 1, except that the compound of Formula B was used instead of the compound of Formula A, the ratio of the compound of Formula B was adjusted so that the value of A in Formula 2 was about 0.15, and the thickness of the silicone adhesive layer was about 8 μm.

[0211] [Formula B]

[0212]

[0213] Comparative Example 1.

[0214] The optical modulation device was manufactured in the same manner as in Example 1, except that the compound of Formula C was used instead of the compound of Formula A, the ratio of the compound of Formula C was adjusted so that the value of A in Formula 2 was about 0.15, and the thickness of the silicone adhesive layer was about 4 μm.

[0215] [Formula C]

[0216]

[0217] Compare Example 2.

[0218] The optical modulation device was manufactured in the same manner as in Example 1, except that the compound of formula C from Comparative Example 1 was used instead of the compound of formula A, the ratio of the compound of formula C was adjusted so that the value of A in Formula 2 was about 0.15, and the thickness of the silicone adhesive layer was about 15 μm.

[0219] Comparative Example 3.

[0220] The optical modulation device was manufactured in the same manner as in Example 1, except that the compound of Formula D was used instead of the compound of Formula A, and the thickness of the silicone adhesive layer was about 5 μm.

[0221] [Form D]

[0222]

[0223] Comparative Example 4.

[0224] The optical modulation device was manufactured in the same manner as in Example 1, except that the compound of formula D from Comparative Example 3 was used instead of the compound of formula A, and the thickness of the silicone pressure-sensitive adhesive layer was about 12 μm.

[0225] Comparative Example 5.

[0226] The optical modulation device was manufactured in the same manner as in Example 1, except that the compound of Formula E was used instead of the compound of Formula A, and the thickness of the silicone pressure-sensitive adhesive layer was about 3.6 μm.

[0227] [Formula E]

[0228]

[0229] Comparative Example 6.

[0230] The optical modulation device was manufactured in the same manner as in Example 1, except that the compound of formula E from Comparative Example 5 was used instead of the compound of formula A, and the thickness of the silicone pressure-sensitive adhesive layer was about 14 μm.

[0231] The K values ​​of the pressure-sensitive adhesive layers of the examples and comparative examples are summarized and described in Tables 1 and 2 below.

[0232] [Table 1]

[0233]

[0234] [Table 2]

[0235]

[0236] The transmittances T1 and T2 determined above for the optical modulation devices of the embodiments and comparative examples are summarized and described in Table 3 below.

[0237] [Table 3]

[0238]

[0239] From the results in Table 3, it can be determined that the optical modulation device according to this application stably maintains the designed liquid crystal alignment characteristics (vertical alignment characteristics) before and after maintaining the high temperature, thus the transmittance measurements T1 and T2 are equal. The vertical alignment characteristics of the optical modulation device at high temperature were further determined in another manner. The vertical alignment characteristics were evaluated while one side of the optical modulation device was illuminated with light without applying an external signal to the device, and while the ambient temperature of the device was changed using a temperature control device (LTS-350, Linkam). Orthogonal polarizing layers are provided on both sides of the optical modulation layer, and therefore, if the vertical alignment is properly maintained, no light leakage occurs on the side of the optical modulation device opposite to the illuminated side. The vertical alignment characteristics were evaluated in the above manner while maintaining the temperature of the device at 100°C, and the results are summarized in Table 4 below. In Table 4 below, P represents the case where no light leakage occurs (when the vertical alignment is stably maintained), and N represents the case where light leakage occurs (when the vertical alignment is not maintained).

[0240] [Table 4]

[0241]

[0242] As summarized in Table 4, it was observed that in the device of the embodiment, the initial vertical orientation was stably maintained even at high temperatures, thus preventing light leakage. However, in the device of the comparative example, the vertical orientation was disrupted at high temperatures, resulting in light leakage.

[0243] Figure 5The results of evaluating the light leakage of Example 1, and Figure 6 This is the result of comparison example 1.

Claims

1. An optical modulation device, comprising: First substrate and second substrate; as well as Liquid crystal layer The first substrate and the second substrate each have a first surface and a second surface. The first substrate and the second substrate are disposed opposite to each other such that the first surface of the first substrate and the first surface of the second substrate face each other. The liquid crystal layer is located between the first substrate and the second substrate. The silicone pressure-sensitive adhesive layer or adhesive layer is on the first surface of the first substrate, and The optical modulation device described herein satisfies the following formula 1: [Formula 1] Wherein, T1 is the initial transmittance measured in the temperature range of 10°C to 30°C after the liquid crystal layer is vertically aligned and placed between orthogonal polarizers, and T2 is the transmittance measured after the liquid crystal layer exhibiting transmittance T1 is held in the vertically aligned state at 100°C for 5 minutes and then placed between the orthogonal polarizers, and T1 and T2 are measured in the wavelength range of 380 nm to 770 nm.

2. The optical modulation device according to claim 1, wherein the transmittance T2 is 2% or less.

3. The optical modulation device according to claim 1, wherein the silicone pressure-sensitive adhesive layer or adhesive layer comprises a compound having three or more substituents of formula 1: [Formula 1] in, R1 to R3 are each independently a hydrogen atom or an alkyl group, but at least two of R1 to R3 are alkyl groups.

4. The optical modulation apparatus according to claim 1, wherein the liquid crystal layer is configured to switch between a vertical alignment state and a twisted alignment state.

5. The optical modulation device according to claim 3, wherein, In Formula 1, any one of R1 to R3 is a hydrogen atom, and the other two are alkyl groups.

6. The optical modulation apparatus according to claim 3, wherein, In Formula 1, any one of R1 to R3 is a hydrogen atom, and the other two are linear alkyl groups having 1 to 20 carbon atoms.

7. The optical modulation device according to claim 3, wherein the compound having three or more Formula 1 substituents comprises 3 to 10 Formula 1 substituents.

8. The optical modulation device according to claim 3, wherein the compound having three or more substituents of formula 1 is represented by formula 2: [Equation 2] in, R4 to R7 are each independently hydrogen, alkyl, or a substituent of formula 1, but three or more of R4 to R7 are substituents of formula 1: [Formula 1] R1 to R3 are each independently a hydrogen atom or an alkyl group, but at least two of R1 to R3 are alkyl groups.

9. The optical modulation device according to claim 3, wherein the silicone pressure-sensitive adhesive layer or adhesive layer comprises the compound having three or more substituents of formula 1 in a ratio of 1% to 50% by weight.

10. The optical modulation apparatus according to claim 3, wherein the value of K according to formula 1 is 2 μm or greater: [Formula 1] in, A is a value determined by Formula 2 below, B is the number of Formula 1 substituents contained in the compound having three or more Formula 1 substituents, and D is the thickness of the silicone pressure-sensitive adhesive layer or adhesive layer, the thickness being in μm: [Formula 2] Wherein, S is the weight of the compound having three or more substituents of Formula 1 contained in the silicone pressure-sensitive adhesive layer or adhesive layer, and O is the weight of the pressure-sensitive adhesive layer or adhesive layer excluding the compound having three or more substituents of Formula 1.

11. The optical modulation apparatus according to claim 10, wherein A in formula 1 is in the range of 0.01 to 0.

5.

12. The optical modulation apparatus according to claim 10, wherein D in formula 1 is in the range of 0.5 μm to 50 μm.

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

14. The optical modulation apparatus of claim 1, wherein a liquid crystal alignment film is formed on the first surface of the second substrate.

15. The optical modulation apparatus of claim 1, wherein the in-plane phase difference between the first substrate or the second substrate and light with a wavelength of 550 nm is 500 nm or greater.

16. The optical modulation apparatus according to claim 1, further comprising a polarizing layer disposed on the second surface of the first substrate or on the second surface of the second substrate.

17. The optical modulation device according to claim 1, further comprising an optically anisotropic film existing between the first substrate or the second substrate and the liquid crystal layer and satisfying the following formula 3: [Formula 3] in, 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.

18. A window comprising the light modulation device according to claim 1.

19. A skylight comprising the optical modulation apparatus according to claim 1.

Images