Liquid crystal assembly

Abstract

Described herein are tunable light liquid crystal (LC) assemblies and techniques for manufacturing LC assemblies. In some embodiments, an LC assembly (900) includes a guest-host (GH) liquid crystal layer (940) including nematic liquid crystals, dye molecules, and chiral dopants. The GH liquid crystal layer (940) is positioned between a pair of substrates (902, 930). The LC assembly (900) is a film assembly, each substrate (902, 930) including a flexible film (914, 922) and a conductive layer (916, 920) formed on the flexible film (914, 922). The substrates (902, 930) are separated by a spacer (938) defining a cell gap. The GH liquid crystal (940) is configured to transition the LC assembly (900) between a darkened and a brightened state in accordance with a voltage across the conductive layers (916, 920). The flexible films (914, 922) allow the LC assembly (900) to conform to the surface of a window or other rigid surface to which the LC assembly (900) is attached. The LC assembly (900) can be connected by liquid or film-based adhesives.

Description

[0001] Related applications

[0002] This application claims the benefits and priority of U.S. Provisional Application No. 63 / 116,751, filed November 20, 2020, and U.S. Non-Provisional Application No. 17 / 529,981, filed November 18, 2021, the entire contents of which are incorporated herein by reference for all purposes. Background Technology

[0003] This disclosure generally relates to liquid crystal components, and more specifically, to various structures incorporating liquid crystal cells and methods for producing such structures. This disclosure also relates to a liquid crystal component that can be dimmed by electrically adjusting the transmittance of one or more liquid crystal cells in the liquid crystal component. Summary of the Invention

[0004] This disclosure relates to a liquid crystal assembly comprising one or more liquid crystal (LC) cells. An LC cell comprises liquid crystal particles contained within a multilayer stack, which may include conductive layers and protective substrates, etc. LC assemblies are typically configured as panels having a relatively large surface area (compared to the surface along its thickness dimension) for receiving light on one side and transmitting light through an opposite side. In some embodiments, the LC assembly is electrically controllable to change its transmittance. In embodiments characterized by an LC assembly having multiple cells, each cell may correspond to a different segment along the surface of the LC assembly, and the transmittance of that segment may be individually controlled to change without affecting the transmittance of other segments. The dimmable LC assembly disclosed herein can be used in various settings, including vehicle settings (e.g., automotive / car windows) and architectural settings (e.g., building windows).

[0005] The structure of an LC assembly can vary depending on the setup and application in which it is used. For example, an LC assembly used in a vehicle environment may include flexible materials for impact resistance and / or adhesive materials to prevent breakage into numerous fragments (pieces) in the event of fracture. LC assemblies used in a vehicle environment preferably resemble multi-layered safety glass, where the layers are capable of breaking into smaller pieces that remain adhered to the adhesive layers or substrate of the LC assembly. Furthermore, LC assemblies including one or more flexible layers (e.g., a flexible substrate) may be easier to install and more tolerant of physical manipulations such as bending. Additionally, since optical clarity is important in vehicle setups, dimmable LC assemblies can be configured to provide variable transmittance with minimal haze or light scattering. This allows the user to see clearly through the LC assembly regardless of variations in light transmittance.

[0006] This disclosure also relates to techniques for manufacturing liquid crystal modules using a manufacturing process that includes laminating layers of different materials together. In some embodiments, the application technique incorporates a bending layer (e.g., a glass plate) into the LC module. This allows the LC module to be shaped suitable for use as a window in a vehicle or in any other application where bending the LC module may be necessary.

[0007] In some embodiments, the dimmable LC component can be controlled based on one or more sensors configured to collect data about the environment surrounding the LC component, such as optical and / or temperature sensors. The sensor data can be processed to automatically perform dimming in response to changes in the environment, such as changes in the position or brightness of a light source in the environment.

[0008] In some embodiments, the application technique laminates the LC assembly at lower temperatures and / or pressures than is typically used. In particular, LC assemblies suitable for use in vehicle environments may include one or more polyvinyl butyral (PVB) layers. PVB lamination typically involves temperatures and pressures exceeding those that the components of the LC assembly can withstand. For example, spacers separating the walls defining the LC cells from the opposing substrate are prone to deformation and / or dislocations in the presence of heat. High temperatures can also introduce defects, such as black spots, into the LC cells themselves. Therefore, in some embodiments, lamination is performed in a vacuum environment to reduce temperature and / or pressure.

[0009] In some embodiments, the application technology lamination includes an LC assembly comprising one or more ultraviolet (UV) blocking layers. Due to the presence of one or more UV blocking layers, UV curing of the adhesive may not be a viable method for joining two or more components together, such as bonding gaskets or washers to a substrate. The inclusion of UV blocking layers can be for any number of reasons. For example, to form a twisted nematic (TN) liquid crystal display, polarizers are added to opposite sides of the LC cells, or introduced as part of the LC cell itself. The polarizer may comprise a polarizer plate with a protective coating designed to protect the polarizer plate from damage. This protective coating may be formed of a UV-blocking material (e.g., cellulose triacetate (TAC)) such that any UV light that passes through the polarizer is insufficient to fully cure the UV adhesive. Therefore, in some embodiments, non-UV adhesives are used, and may include, for example, epoxy adhesives or thermally activated adhesives. Such alternative adhesives may present additional challenges not present when using UV adhesives. For example, epoxy adhesives have a limited working time before curing, so the time window for repositioning the parts to be joined (e.g., correcting misalignment) may be short. Furthermore, as mentioned above, introducing heat may damage high-temperature sensitive components, such as spacers within the LC cell or the LC cell itself.

[0010] As described above, in some embodiments, the LC assembly may include one or more flexible layers. The LC assembly described herein may include rigid and / or flexible substrates. Specifically, the substrate may be formed as a flexible film (e.g., a flexible material layer with a thickness of about 200 μm or less) including a conductive material coating. The flexible substrate may include TAC (triacetate), polycarbonate (PC), polyethylene terephthalate (PET), or other flexible materials. Flexible substrates can be used to construct flexible LC assemblies. For example, an LC assembly may be formed without glass or other rigid substrates and with sufficient thickness to allow the entire LC assembly to function as a flexible film. An LC assembly comprising one or more flexible films is referred to herein as an LC film assembly. If a rigid substrate is used to form the LC assembly (e.g., including or encapsulating LC cells between glass plates), such an assembly can be used as a stand-alone window. Alternatively, some embodiments are characterized by a flexible substrate that allows the LC assembly to be applied as an additional component to windows or other off-the-shelf rigid surfaces (e.g., as a film using a transparent, water-based, or solvent-based adhesive). Flexible LC components are advantageous when the surface on which the LC component is applied is a curved surface, because the LC component can conform to the curvature of the surface, thereby eliminating or at least substantially minimizing the presence of bubbles or gaps between the LC component and the surface.

[0011] The techniques described herein for manufacturing LC components can be implemented using a computer system having one or more processing units (e.g., general-purpose processors) configured to perform specific operations or actions (e.g., controlling temperature and / or pressure) by accessing software, firmware, hardware, or a combination thereof mounted on the system. One or more computer programs can be configured to perform specific operations or actions by including instructions executable by one or more processing units. One or more computer programs can be stored on a non-transitory computer-readable medium (e.g., a computer storage device forming memory) accessible to one or more processing units. Attached Figure Description

[0012] Figure 1 This section provides an example of an environment where LC components can be used.

[0013] Figures 2A to 2C An example of how a dimmable LC component can be segmented is shown.

[0014] Figures 3A to 3C Examples of different control schemes for selective dimming segments are illustrated according to some embodiments.

[0015] Figure 4 An example of an LC component including an asymmetric dimmable segment is shown according to an embodiment.

[0016] Figure 5A and Figure 5B An example of a dimming system according to an embodiment is shown.

[0017] Figure 6A This is a simplified block diagram of the control unit according to an embodiment.

[0018] Figure 6B An example arrangement of components for a control unit related to a window is shown.

[0019] Figures 7A to 7C An example of a liquid crystal cell that can be used to form an LC component according to some embodiments is illustrated.

[0020] Figures 8A to 8D Voltage-transmittance curves for some exemplary dimmable LC components are shown.

[0021] Figures 9A to 9C An example of an LC component including a PVB layer is illustrated according to some embodiments.

[0022] Figure 10 An example of a system for laminating LC components including PVB, according to some embodiments, is shown.

[0023] Figure 11 The UV curing step applied to the LC unit is shown.

[0024] Figure 12A and Figure 12B An example of an LC assembly including an indium tin oxide (ITO) electrode and a polarizer with cellulose triacetate (TAC) is illustrated according to some embodiments.

[0025] Figure 13 The expansion of the LC panel during lamination with the PVB panel and the glass panel is shown.

[0026] Figure 14 An LC assembly having a liquid and a film-based adhesive is shown according to some embodiments.

[0027] Figure 15 The shear stress generated in the LC assembly when it rests against a surface is shown.

[0028] Figures 16 to 19 An example of an LC component attached to a mounting body according to some embodiments is shown.

[0029] Figure 20 and Figure 21 An LC assembly suitable for attachment to a glass surface is shown according to some embodiments.

[0030] The accompanying drawings depict embodiments of the present disclosure for illustrative purposes only. Those skilled in the art will readily recognize from the following description that alternative embodiments of the illustrated structures and methods may be employed without departing from the principles of the present disclosure or the benefits proclaimed.

[0031] In the accompanying drawings, similar components and / or features may have the same reference numerals. Furthermore, various components of the same type can be distinguished by adding a dash after the reference label and a second label to differentiate similar components. If only the first reference numeral is used in the specification, the description applies to any similar part having the same first reference numeral, regardless of the second reference numeral. Detailed Implementation

[0032] In the following description, specific details are set forth for purposes of explanation to provide a full understanding of certain inventive embodiments. However, it will be apparent, however, that various embodiments may be practiced without these specific details. These figures and descriptions are not intended to be limiting.

[0033] This disclosure relates to a liquid crystal (LC) module comprising one or more liquid crystal cells. In some embodiments, the LC module is electrically controllable to change its transmittance, i.e., dimmable. In embodiments characterized by an LC module having multiple cells, each cell may correspond to a different segment along the surface of the LC module, and the transmittance of that segment may be individually controlled to change without affecting the transmittance of other segments. The dimmable LC module disclosed herein can be used in various settings, including vehicle settings (e.g., automobile / car windows) and architectural settings (e.g., building windows).

[0034] As used herein, the term "tunable" refers to the ability to change light transmittance up or down via one or more control signals. For example, an LC cell may include a pair of electrodes on opposite sides of a liquid crystal layer, wherein a voltage applied across the electrodes causes liquid crystal particles (e.g., individual liquid crystal molecules) to align in such a way that the LC cell is darkened by reducing the amount of light that can pass through it. Various types of tunable LC cells exist, including twisted nematic (TN), guest host (GH), and vertically aligned (VA) types. A tunable LC cell can be configured such that its transmittance is highest when the value of the control signal is at its lowest value (e.g., zero volts). Such a cell is sometimes referred to as "normal white" (NW). Alternatively, a tunable LC cell can be configured such that its transmittance is lowest when the value of the control signal is at its lowest / zero-volt "normal black" (NB).

[0035] The embodiments disclosed herein can be used to implement liquid crystal displays (LCDs), including dimmable LCDs. Although LCD structures are not specifically discussed, it should be understood that the LC components described herein can be adapted to form LCDs by, for example, adding monochromatic or multicolor (e.g., red-green-blue) backlighting.

[0036] Some embodiments of this disclosure relate to curved windows or LC assemblies such that the surface of the window or LC assembly has a three-dimensional curvature (e.g., bulging toward the external environment) rather than being flat.

[0037] This disclosure also relates to techniques for manufacturing LC components, including LC components that can be dimmed by electrically controlling the light transmittance of one or more LC cells in the LC component. Some embodiments relate to dimming components that can be used as windows or incorporated into windows. Generally, a window is any substantially rigid structure through which light can be transmitted. In the case of a dimming window, the degree to which light can be transmitted through the window is controllable within a range of transmittance values. Windows can be curved or flat, can have any number of shapes (rectangular, triangular, circular, etc.), and can be enclosed in a frame or frameless. Furthermore, an important aspect of a window for viewing is optical clarity, for example, the absence of haze / cloudiness, black spots, or visual distortion.

[0038] To make LC components, particularly dimmable LC components, suitable for use as windows or in windows and in safety-critical environments, this paper describes specific types of materials and methods for combining such materials with other components of LC components to form laminated structures. An example of a safety-critical environment is... Figure 1 The vehicle shown is an example. Other types of environments that may benefit from the LC component according to embodiments described herein include, for example, aircraft (e.g., airplanes), spacecraft, ships (e.g., boats), public or commercial vehicles (e.g., trucks or buses), or other vehicles, as well as built environments. For example, the LC component can be used in building windows, glass walls, or building doors.

[0039] Figure 1 An example of an environment in which LC components can be used is shown. For example... Figure 1 As shown, the car 120 may include a front windshield (also called a windshield glass) 122, a rear windshield 124, a sunroof 126, and side windows 128. Figure 1In the example, car 120 also includes a quarter-glass window 129. Quarter-glass windows are typically smaller than the side windows of a car and are usually located above the rear wheels or next to the side mirrors. Due to their position relative to the body, quarter-glass windows are generally essentially triangular. Typically, each of windows 122, 124, 126, 128, and 129 is curved, with the degree of curvature varying between the windows. For example, the windows of car 120 may exhibit a three-dimensional curvature, such that one surface of the window is convex (e.g., the surface facing the external environment), while the opposite (e.g., the interior) surface is concave. Figure 1 In the example, the LC component can be formed or adapted onto any of windows 122, 124, 126, 128, and 129. The vehicle 120 may also include one or more sensors 150, as described below, which can be used to control the dimming of the LC component in the vehicle 120.

[0040] Vehicles can move rapidly under varying lighting conditions, such as from a sunny open road to a dark tunnel. Because lighting conditions change, it is beneficial to make at least some of windows 122, 124, 126, 128, or 129 dimmable. For example, making the windshield dimmable can increase driver comfort and thus driving safety if the dimming of the windshield 122 is controlled to reduce light transmittance when the surrounding environment is relatively bright and / or increase light transmittance when the surrounding environment is darker. Dimming can be performed when the intensity of ambient light exceeds a threshold (e.g., when the windshield 122 or a portion of the windshield near the driver receives direct sunlight), or when the driver's eyes have darkened to the point of adaptation to a darker environment over time.

[0041] Dimming can be controlled in other ways to improve the safety and / or comfort of the vehicle's driver or passengers. For example, prolonged exposure to bright light, especially sunlight, tends to increase the temperature inside the vehicle cabin. Therefore, light transmittance can be reduced based on a cabin temperature exceeding a threshold. Dimming can be performed based on ambient light intensity, temperature, temperature combined with ambient light intensity, and other factors or combinations thereof. Thus, in some embodiments, one or more sensors 150 may include optical sensors and / or other types of sensors (e.g., temperature sensors or light intensity sensors) deployed together with the dimmable LC assembly and control unit, the control unit being configured to change the light transmittance of the dimmable LCD assembly based on data from the sensors. Such sensors 150 may be located at various locations throughout the vehicle 120 and, in some cases, may be integrated with or connected to the windows, for example, as part of the LC assembly.

[0042] Another example of a sensor 150 that can be used to control dimming is an occupant sensor configured to detect the presence of someone in the vehicle 120, for example, based on a fastened seatbelt, the pressure of the occupant's weight on the seat, or an image of the occupant captured by an onboard camera. The light transmittance of windows near or facing occupants can be controlled to increase occupant comfort, and occupant sensing can be incorporated into the control unit's decisions regarding whether to adjust the light transmittance and, if so, to what extent. For example, when no passenger is facing the window, it may not be necessary to adjust the window's transmittance. This is also true even in the case of the windshield 122, as the vehicle 120 may be an autonomous or remotely controlled vehicle with no one in the driver's seat.

[0043] While dimmable LC modules can be used in other types of applications, integrating them into windows in safety-critical environments is challenging. As mentioned above, windows 122, 124, 126, 128, or 129 are typically curved. Therefore, the dimmable LC module should also be curved or able to match the curvature of the window to which the dimmable LC module is applied. Furthermore, automotive windows are often subject to stringent regulations designed to ensure safety. For example, UNECE Regulation 43 specifies various performance requirements for different types of windows. The window types governed by Regulation 43 include “tempered glass” (a single pane of glass specially treated to enhance its mechanical strength and regulate its fragments after breakage), “laminated glass” (two or more layers of glass held together by one or more plastic interlayers), “treated laminated glass” (at least one of the multiple glass layers is specially treated to enhance its mechanical strength and regulate its breakage after breakage), and “plain laminated glass”, where none of the glass layers are treated.

[0044] The performance requirements specified in Regulation 43 cover shatter resistance, mechanical strength (e.g., drop ball test), abrasion resistance, temperature resistance, radiation resistance, humidity resistance, light transmittance, optical distortion, color, fire resistance, and other properties. When modifying automotive windows to include dimmable LC modules, compliance with regulations such as Regulation 43 can be difficult and may also impose restrictions on how dimmable LC modules can be manufactured.

[0045] Figure 2A A dimmable windshield 210 is shown. The windshield 210 is dimmable due to the presence of a dimmable LC assembly integrally formed with or attached thereto. The windshield 210 is divided into multiple segments 202-1 to 202-3, each segment 202 being independently dimmable. For example, each segment 202 may correspond to an LC unit that can be dimmed by applying a voltage across the electrodes of the LC unit. Figure 2AIn the example, the segments are arranged vertically. The segments 202 of the windshield 210 can be controlled individually or in combination to selectively darken different areas of the windshield 210.

[0046] Figure 2B A windshield 220 with horizontally arranged segments 204-1 to 204-5 is shown. (As shown) Figure 2C As shown, dimmable segments can also be arranged in two dimensions. Figure 2C In this case, the sunroof 230 is divided into four sections 206-1 to 206-4. For example, each section 206 can be located above different seats in the car.

[0047] Figures 2A to 2C The segmentation shown can be achieved by forming each segment as an independent LC assembly. For example, each segment 206 can be formed as a separate LC assembly. When placed adjacent to each other, the LC assemblies can be separated by small gaps, though these gaps are imperceptible to the naked eye. Alternatively, segment 206 can correspond to different cells within a single LC assembly, which has been partitioned to provide isolation chambers for the liquid crystal material. The thickness of the material separating adjacent cells of such LC assemblies (e.g., rubber gaskets or other types of sealants) can also define gaps that are not visible from normal viewing distances or are at least difficult to detect at a glance. For example, gaps in the windshield may be difficult to see when viewed from the driver's seat through the windshield. Segmentation can also be applied to a single LC cell by patterning a conductive layer to form multiple pairs of electrodes sharing the same volume of liquid crystal. Figures 2A to 2C As shown and in Figure 4 In the example (discussed below), LC components can be segmented in any number of ways, including segments with different segmentation schemes or segments with different shapes.

[0048] Figures 3A to 3C Examples of different control schemes for selective dimming segmentation according to some embodiments are shown. Figure 3A In the middle, the transmittance of the left side of the windshield 122 (e.g., the driver's side) decreases, resulting in a corresponding decrease in the amount of sunlight 140 reaching the eyes 300 of a person inside the car 120 through the windshield 122. Dimming can be performed manually or automatically based on sensor data, as described above. Figure 3B In the middle, the entire windshield 122 darkened. Figure 3B The darkening can be achieved by jointly controlling each section of the windshield 122. Figure 3C In this way, the left side of the windshield 122 is darker than the right side to counteract glare from sunlight 140.

[0049] The tunable LC module described herein can be configured to allow light transmittance to vary within a predefined range, so that even at the lowest transmittance level, at least some light can pass through the LC module. For example, as Figure 3B As shown, even after the entire windshield is darkened, the tree 130 outside the car 120 remains visible. The ability to see through the windshield is crucial for operating the vehicle and highlights a key difference between dimmable LC technology designed for safety and comfort and dimmable LC designed for other types of applications such as privacy. In the former, light transmittance can be finely controlled through many levels of transmittance, and maintaining a high level of optical clarity is generally desirable. In contrast, dimmable LC components designed for use as privacy screens (e.g., protecting a conference room from peeping) typically have a binary operating mode: the liquid crystal is either transparent or opaque. Furthermore, in the context of a privacy screen, opacity does not necessarily mean reducing transmittance to zero or near zero. Rather, an opaque mode can be one where some light still transmits, but the image seen through the privacy screen is blurry or blurred.

[0050] Figure 4 An example of an LC assembly 400 including an asymmetric dimmable segment 402 according to one embodiment is shown. The segment 402 is shaped as a polygon. However, the segment can be formed in any shape based on the geometry of the LC cell to which it corresponds. An LC assembly including a dimmable segment can also include one or more non-dimmable segments. For example, the entire area outside the segment 402 can be made non-dimmable by omitting one or more components that contribute to the dimming capability of the segment 402 from this area. For example, the area outside the segment 402 may not have electrodes or polarizers.

[0051] Figure 5A and Figure 5B An example of a dimming system 500 according to one embodiment is shown, including an LC component 510 attached to a window 520. The LC component 510 may correspond to any dimmable LC component described herein. For example, the LC component 510 may include a twisted nematic (TN) liquid crystal cell, as described below, which includes polarizers on opposite sides of a liquid crystal layer. Figure 5A As shown, except for a small notch 512 in one corner, the LC component is substantially the same size and shape as the window 520. This notch provides space for attaching the control unit 530 to the window 520. Therefore, the dimming system 500 corresponds to the entire LC component formed by combining the LC component 510, the window 520, and the control unit 530. Figure 5A and Figure 5BThis is merely an example. In other embodiments, the control unit 530 may be located in other locations, such as at the center of the window 520 and attached to the surface of the LC assembly 510, rather than being directly attached to the window 520. In practice, the LC assembly 510 and the window 520 may not completely overlap. For example, the LC assembly 510 may be 1 mm or more smaller than the window 520 on each side. However, the LC assembly 510 may be manufactured in different size configurations to match various window sizes.

[0052] The LC assembly 510 and control unit 530 may be provided in the kit, which may also include a flexible cable for electrically coupling the LC assembly 510 and the control unit 530, an adhesive for attaching the LC assembly 510 and / or the control unit 530 to the window 520, a tool (e.g., a scraper) for extruding air bubbles between the LC assemblies 510, and / or other accessories for facilitating the installation of various components of the dimming system 500.

[0053] Figure 5B This is a side view of the dimming system 500. Figure 5B As shown, the LC component 510 is attached to the surface 522 of the window 520. The window 520 may include rigid glass and may be, for example, an architectural window or an automotive window (e.g., a sunroof). While not strictly necessary, the surface 522 is generally preferred to be the inner surface of the window 520, for example, the interior of a car cabin or building or room. Such an arrangement will protect the LC component 510 from damage or contaminants from the external environment. The LC component 510 can be attached to the surface 522 in various ways. One option for attaching the LC component 510 is to use a transparent adhesive, which may be sprayed or otherwise applied to the surface 522 and / or surface of the LC component 510. The adhesive may be water-based or solvent-based. For example, the adhesive may be a solution of water and soap. After wetting the LC component 510 or the surface 522 with the solution, the LC component 510 may be placed in contact with the surface 522, and the solution causes the LC component 510 to adhere to the surface 522 in a thin film manner. Once the solution dries, the soap forms a bond that holds the LC component 510 on the surface 522. The bonding is strong enough to prevent the LC assembly 510 from detaching, but weak enough to allow manual removal of the LC assembly. The control unit 530 can be attached to the window 520 in a similar manner using the same or a different adhesive. Alternatively, the control unit 530 can be connected to the LC assembly 510 via a socket or connector, such that the control unit 530 remains in place relative to the window 520, but is not directly connected to the window.

[0054] In some embodiments, the LC assembly 510 may include a pre-existing adhesive on its window-facing surface. This adhesive may be applied during the manufacture of the LC assembly 510 and may be, for example, a liquid adhesive sprayed onto the window-facing surface and allowed to cure. Alternatively, the pre-existing adhesive may be a film-based adhesive. Film-based adhesives may be carried on a transparent, flexible film, such as a film similar to single- or double-sided adhesive tape. Furthermore, the film-based adhesive may cover the cutout 512 to allow attachment of the control unit 530 without a separate adhesive. A temporary protective film may be used to cover the prepared adhesive, allowing the LC assembly 510 to be peeled and glued to the window 520.

[0055] like Figure 5B As shown, the LC component 510 can be much thinner than the window 520. Furthermore, the LC component 510 can be formed using a flexible substrate and may optionally include a flexible additional layer. Conventional liquid crystal cells are formed from liquid crystal material sandwiched between a pair of rigid substrates (e.g., glass). According to some embodiments, a flexible substrate can replace at least one of these rigid substrates. Additionally, the flexible substrate can serve as the window-facing layer of the LC component 510. Including a flexible substrate is advantageous because it allows the LC component 510 to conform to the surface 522 of the window. Although the surface 522 is shown as flat, there may be slight differences in height along the surface 522. These differences may be imperceptible to the naked eye but can lead to gaps or bubbles between the LC component 510 and the surface 522. Gaps or bubbles can be noticeable to the user and can also increase the chance of the LC component 510 delaminating from the window 520. A flexible substrate will reduce the frequency of such gaps or bubbles, and residual gaps or bubbles can be squeezed out by applying manual pressure or using a tool such as a scraper or rolling pin. Squeezing can be performed, for example, before the adhesive solution dries. Furthermore, as mentioned above, some windows are curved. Including a flexible substrate will help the LC component 510 conform to such a window (e.g., Figure 1 The curvature of one of the windows (122, 124, 126, 128 or 129) in the window.

[0056] Control unit 530 is configured to change the transmittance of LC component 510 by outputting one or more control signals to LC component 510. Cutout 512 allows control unit 530 to be attached separately from LC component. Therefore, control unit 530 may include an electrical interface to LC component 510. The electrical interface may include a physical connector for establishing a wired connection to the electrodes of LC component 510. For example, LC component 510 may include a connector that may be coupled to the connector of control unit via a flexible cable or via direct coupling of the connector. Control unit 530 may be attached to window 520 in a similar manner to LC component 510, for example, using the same adhesive. (See below for reference.) Figure 6A To describe a more detailed example of the control unit.

[0057] In alternative embodiments, the LC assembly 510 may not include any cutouts to accommodate the control unit 530. Instead, the control unit 530 may be located outside the area of ​​the window 520 (e.g., mounted on a wall adjacent to the window 520) or on the LC assembly 510 itself. Generally, there are no restrictions on where the control unit 530 can be placed, as long as it can provide control signals for changing the transmittance of the LC assembly 510. For example, in an automobile, the control unit 530 may be co-located or integrated with the vehicle's electronic control unit (ECU) and may be connected to multiple LC assemblies via cables extending inside the vehicle body. As another example, if the window 520 has a frame, the control unit 530 may be placed along the edge or corner of the frame. Alternatively, in some embodiments, the control unit 530 may be integrally formed with or pre-attached to the LC assembly 510 (e.g., via a film-based adhesive also used for attaching to the LC assembly), such that the LC assembly 510 and the control unit 530 are mounted to the window 520 as a single unit.

[0058] The control unit 530 can be powered by an internal battery or an external power source. In some embodiments, for example... Figure 6A In the illustrated embodiment, the power source is a rechargeable battery. Various recharging methods can be used to replenish the energy stored in the battery. For example, such as... Figure 6A As shown, photovoltaic cells can be used to recharge batteries using ambient light.

[0059] Figure 5A and Figure 5B An example of a dimming system is shown, in which the LC component is applied to a window as an "aftermarket" product. That is, the LC component is manufactured separately from the window and can be connected, for example, by the window manufacturer or the user. However, in some embodiments, the dimmable LC component can be integrally formed with the window.

[0060] Figure 6AA simplified block diagram of a control unit 600 according to one embodiment. The control unit 600 can correspond to Figure 5A The control unit 530 includes a photovoltaic cell 610, a battery 620, and a control module 630. The photovoltaic cell 610, battery 620, and control module 630 may be located in the same location. For example, the control unit 600 may include a printed circuit board (PCB) on which the photovoltaic cell 610, battery 620, and control module 630 are mounted. The control unit 600 may also include a housing having an opening or window that allows light to enter the photovoltaic cell 610.

[0061] Photovoltaic cell 610 is configured to convert light into an electrical signal, which charges cell 620. If control unit 600 is placed in an area not covered by LC components (e.g., Figure 5A In the notch 512, the photovoltaic cell 610 will be able to receive unmodified light that has passed through the LC module. Alternatively, if the control unit 600 is positioned such that the light received by the photovoltaic cell 610 is light that has already passed through the LC module, then the photovoltaic cell 610 will generate less energy when the transmittance of the LC module is set low. However, it is expected that even at the lowest transmittance level, some light will pass through the LC module. Therefore, the photovoltaic cell 610 can recharge the cell 620 at any time when the LC module also receives light, but charging may be less efficient when there is no notch.

[0062] Battery 620 can be any type of rechargeable battery and preferably has a small form factor to minimize the footprint of control unit 600. For example, battery 620 can be a lithium-ion coin cell battery. Battery 620 supplies power to control module 630, enabling control module 630 to perform its operations.

[0063] The control module 630 can be implemented in hardware and / or software. For example, the control module 630 can be implemented using circuitry such as an integrated circuit (IC), a field-programmable gate array (FPGA), a microcontroller, etc. The control module 630 is configured to set the transmittance level of the LC component via one or more control signals 602 that can be output from the electrical interface 612 of the control unit 600. For example, the electrical interface 612 may include a connector or receptacle suitable for receiving a cable, wherein the cable includes a first wire leading to a first electrode of the LC component and a second wire leading to a second electrode of the LC component.

[0064] The control module 630 can set the transmittance level based on manual input or automatically. For example, manual input can be provided via a touch sensor or physical button on the control unit 600. In some embodiments, the control module 630 can set the transmittance level based on a wireless command from a user device, such as a command sent from a mobile phone via Bluetooth or Wi-Fi connection. Alternatively, or as an alternative to manual input, the control module 630 can use sensor data to determine the transmittance level to be set. As mentioned above, such sensors can include optical sensors, temperature sensors, or other types of sensors. Therefore, as... Figure 6A As shown, the control unit 600 may include an additional electrical interface 614 through which sensor data 604 is received from one or more external sensors. In some embodiments, the electrical interface 614 may be a wireless interface. Furthermore, in some embodiments, electrical interfaces 612 and 614 are combined into a single interface, such as a communication bus.

[0065] One or more sensors providing sensor data 604 can be located in various locations, including on the LC module, on a window, on the control unit 600, or elsewhere in the environment (e.g., inside a vehicle cabin). Furthermore, the sensors providing sensor data 604 can be part of the control unit 600 itself. For example, a photovoltaic cell 610 can be used as an optical sensor. Since the energy produced by the photovoltaic cell 610 is proportional to the amount of light incident on it, the output of the photovoltaic cell 610 (e.g., an electrical signal charging the battery 620) can be measured to determine the intensity of ambient light. This determination can be performed by the control module 630, possibly taking into account the current transmittance level of the LC module, depending on whether the photovoltaic cell 610 receives unmodified light or modified light passing through the LC module. Alternatively, a separate optical sensor, such as a photodiode, can be provided. For example, a photodiode can be integrated into the window-facing side of the LC module such that it receives unmodified light passing through the LC module.

[0066] Figure 6B An example of how the components of the control unit 600 can be arranged relative to window 520 is shown. Figure 6B The image is shown as being covered by LC component 510, similar to... Figure 5A .exist Figure 6B In the middle, the control unit is located in the lower right corner of window 520, similar to... Figure 5A The arrangement shown is as follows. Figure 6BAs shown, the control unit 600 may include a solar panel 650 and a circuit 660. The solar panel 650 corresponds to one or more instances of the photovoltaic cell 610 and is arranged side-by-side with the circuit 660. The circuit 660 includes a control module 630 and, in some embodiments, includes a battery 620 (e.g., control module 630 and battery 620 mounted on the same PCB). Alternatively, the solar panel 650 and the circuit 660 may be stacked on top of each other. For example, the circuit 660 may be placed on top of the solar panel 650 such that the circuit 660 is further away from the window 520 than the solar panel 650.

[0067] Although the control unit 600 is described as having a photovoltaic cell coupled to a battery, the power source for the dimmable LC module can take other forms. For example, the power source could be a disposable battery, a battery rechargeable by plugging into an external power source, or an external power source directly connected to the control unit 600. In embodiments characterized by a photovoltaic cell, the LC module is typically in a normally white configuration to reduce power consumption. A white configuration can also be used when the lighting state should be the default or fail-safe operating mode, for example, when the LC module is part of a motorcycle helmet visor. A normally black configuration for the dimmable LC module can be used in applications where the dimming state is the normal operating mode or where the normal operating mode is the brightening state but the cost of maintaining the electric field across the conductors of the LC module is less of a concern.

[0068] Figures 7A to 7C Examples of liquid crystal cells that can be used to form LC components according to some embodiments are shown. Figure 7A In the liquid crystal unit 700, there are a first substrate 702, a first electrode 704, a sealant 706, a spacer 708, a second electrode 710, a second substrate 712, and liquid crystal 714.

[0069] The first substrate 702 and the second substrate 712 can be made of transparent materials, allowing the incident light 730 to pass through the liquid crystal propagation 714 and become the emitted light 732. The first substrate 702 and the second substrate 712 can be made of materials such as glass or some other rigid materials. Alternatively, at least one substrate 702, 712 can be formed of a flexible material such as polycarbonate (PC), polyethylene terephthalate (PET), or cellulose triacetate (TAC), which allows the liquid crystal cell 700 to conform to curved surfaces, such as windshields, curved architectural glass panels, etc.

[0070] Sealant 706 defines the sidewalls 700 of the LC cell, the cell space 702 between the first substrates, and the liquid crystal filling 714 between the second substrate and the first substrate 712. Sealant 706 acts as a gasket to isolate the liquid crystal 714 from environmental influences and securely confine the liquid crystal 714; it is sandwiched between substrates 702 and 712. Sealant 706 can be formed from plastic, elastomeric materials, or other relatively soft materials, for example, using plastic injection molding. Furthermore, in some embodiments, additional seals may be provided. Figure 7A (Not depicted) serves as a circumferential seal between LC units 700 and other layers (e.g., glass panels) of the LC assembly containing LC units 700. When provided, this circumferential seal can seal the sandwich structure in a "floating" manner by acting as a buffer pad between the sandwich structure and other layers of the LC assembly. An example of such an additional seal is shown in... Figure 14 (As described below) is shown as an edge seal.

[0071] The spacer 708 can provide structural support between the first substrate 702 and maintain a uniform unit gap distance d between the substrates with the second substrate 712. The spacer 708 may include, for example, silicone balls, plastic balls, etc., and may be coated with a black coating to reduce light transmission. Although Figure 7A Only two spacers 708 are shown as illustrated. An LC assembly according to embodiments described herein may include any number of spacers between a pair of substrates on opposite sides of the liquid crystal. Spacers 708 may be secured between substrates 702 and 712, for example, bonded to electrodes 704 and 710 by adding an adhesive. In some embodiments, the adhesion of electrodes 704 and 710 between the spacers may be the result of a baking process. The temperatures and pressures at which baking is performed are typically significantly lower than those used for laminating automotive windows with polyvinyl butyral (PVB) as a constituent layer. Alternatively, spacers 708 may be secured in place by friction or compression. Furthermore, in some embodiments, spacers 708 may be movable. For example, spherical spacers may roll freely within the liquid crystal material. In cases where the LC assembly is mounted vertically, spacers for securing the bonding may be advantageous, such as when the LC assembly is attached to a building window. When the LC assembly is mounted vertically, gravity tends to cause the liquid crystal to accumulate around the sidewalls closest to the ground, which may result in a wider cell gap at the bottom of the LC assembly than at the top. Because the spacers for fixed bonding are fixed, uniform cell spacing can be maintained regardless of the orientation of the LC assembly.

[0072] PVB is frequently used in automotive windows to improve impact resistance and reduce fragmentation. Therefore, one aspect of this disclosure relates to a technique for forming LC components comprising one or more PVB layers. This would allow LC components to be incorporated into automotive windows without requiring the replacement of PVB with another material. Automakers are familiar with PVB and the processes used to manufacture windows with PVB, and it would be impossible to switch to a different material without a new manufacturing process. Since automakers may be unwilling to invest the time and resources to develop such a new manufacturing process, PVB-compatible LC components would facilitate bringing LC components for automotive applications to market.

[0073] The first electrode 704 and the second electrode 710 may correspond to conductive material coatings on substrates 702 and 712. For example, the first electrode 704 and the second electrode 710 may comprise indium tin oxide (ITO), which would allow electrodes 704 and 710 to conduct voltage that establishes an electric field on the liquid crystal 714 to change the orientation of the liquid crystal particles. As described below, the orientation of the liquid crystal particles in the liquid crystal 714 can adjust the overall transmittance of the liquid crystal cell 700 and the intensity of the emitted light 732.

[0074] The first electrode 704 and the second electrode 710 may optionally include a rubbing pattern to align the liquid crystal particles of the liquid crystal 714 in a default orientation, which can set the initial / default state of the transmittance of the liquid crystal cell 700. Alternatively, in some embodiments, the rubbing pattern may be located on an additional layer between the electrodes 704, 710 and the liquid crystal 714. Such an additional layer may be formed, for example, using polyamide (PI). Depending on the configuration of the liquid crystal, the rubbing pattern may be omitted. As described below... Figure 20 and 21 As described, a normally black LC module incorporating a guest-host (GH) liquid crystal can be implemented without a rubbing pattern, while a normally white LC module incorporating a GH liquid crystal can include a rubbing pattern on a PI layer.

[0075] Figure 7A This is a simplified example intended to illustrate typical components of the LC assembly described herein with respect to other embodiments. From these other embodiments (e.g., Figures 9A to 9C As will be apparent from the discussion of the embodiments shown, the LC assembly may include more or fewer components, or different arrangements of components. For example, in some embodiments, the LC assembly may include an infrared (IR) filter for blocking IR light and / or an ultraviolet (UV) filter for blocking UV light. UV or IR filters can be beneficial for glare protection and for preventing overheating due to electromagnetic radiation of wavelengths associated with IR or UV. Similarly, in some embodiments, the LC assembly may include an anti-reflective coating as one or more layers.

[0076] Figure 7BAn example configuration of the liquid crystal 714 is shown to provide adjustable light transmittance. (As shown) Figure 7B As shown, liquid crystal 714 can be configured as a twisted nematic (TN) liquid crystal. Liquid crystal particles can be arranged using the aforementioned rubbing pattern to form a twisted helical structure without an applied electric field (e.g., at zero volts). When polarized light passes through the liquid crystal layer, the helical structure can rotate the polarization axis of the polarized light, the rotation angle being adjustable by an electric field applied to the liquid crystal layer (e.g., an electric field generated by control unit 600). When polarized light passes through the liquid crystal layer, the helical structure causes the polarization axis of the polarized light to rotate by a certain angle (e.g., 90°), determined by the rubbing pattern. If an electric field is applied, the liquid crystal particles can be aligned parallel to the electric field. When light passes through the aligned liquid crystal particles, the polarization axis of the polarized light can remain unchanged and not rotate. Embodiments characterized by TN liquid crystals are not limited to the configuration of rotating the helical structure by a 90° twist angle. For example, in some embodiments, the LC component can be configured to rotate the helical structure by 180° to 270° (a feature of super-twisted nematic (STN) displays). In some embodiments, the rotation may be less than 90° (sometimes used to form hybrid mode TN (MTN) displays). Furthermore, TN liquid crystals can include nematic liquid crystals with chiral dopants that impart chirality to the nematic liquid crystals. Therefore, a TN liquid crystal can be any liquid crystal with a twisted structure in its default or voltage-off state, i.e., before an electric field is applied to "untangle" the liquid crystal particles. Furthermore, although... Figure 7B A single rotation direction is described, but in some embodiments, the LC assembly may have liquid crystals in two or more rotation directions to, for example, allow the liquid crystal particles in the first segment to have a different arrangement than the LCD particles in the second segment.

[0077] In some embodiments, the conductive layer corresponding to the electrodes can be divided into different regions. For example, the layer corresponding to electrode 704 and the layer corresponding to electrode 710 can each be divided into different regions corresponding to segments, which can differ in shape and / or size. Different regions can be formed by chemically or mechanically etching the conductive layer to form an etch pattern. The etched pattern differs from the aforementioned rubbing pattern (which sets the general and initial alignment of the liquid crystal) and can be used to form discrete segments, or, in the case of an LCD, to form discrete pixels (e.g., red, green, or blue sub-pixels). By controlling the liquid crystal arrangement in the segment to display stripes, logos, text, or other graphics, such segments can be individually dimmed with or without the aid of an electrically controlled illumination source such as a backlight. For example, an LC component can be configured as a seven-segment display, where different combinations of dimming the seven segments result in the display of different digits. Therefore, the conductive layer can include multiple electrodes that combine with corresponding electrodes on the opposite conductive layer to form different electrode pairs. Each pair of electrodes can correspond to a different region, which can be individually controlled by applying a corresponding electrical signal to establish a voltage on that pair of electrodes.

[0078] like Figure 7B As shown, the liquid crystal 714, the first substrate 702, and the second substrate 712 can be sandwiched between the first polarizing layer 726 and the second polarizing layer 728. Alternatively, the polarizer layers 726 and 728 can be intervening layers between the substrates 702 and 712 and the liquid crystal 714. In a normally white configuration, the first polarizing layer 226 can have a polarization axis a, while the second polarizing layer 228 can have a polarization axis B. The two polarization axes can form a 90-degree angle relative to each other. The incident light 730 can be linearly polarized by the first polarizer layer 726. The linearly polarized light can be rotated by the liquid crystal 714 by the angle configured by the TN structure as described above. Maximum transmittance can be achieved without applying an electric field. When no electric field is applied, the liquid crystal 714 rotates the polarization axis of the polarized light to align it with the polarization axis B when the polarized light reaches the second polarizer layer 728. Minimal transmittance can be achieved when the polarization axis of polarized light does not rotate due to the application of an electric field, such that when the polarized light reaches the second polarizer layer 728, its polarization axis becomes perpendicular / orthogonal to the polarization axis B. In this case, the polarized light is aligned with the absorption axis of the second polarizer layer 728 and can be absorbed by the second deflector layer 726 with maximum absorption. The magnitude of the electric field determines the rotation angle of the polarized light, which can change the portion of the incident light 730 that passes through the liquid crystal cell 714 as the outgoing light 732. The typical range of light transmittance achievable by a TN liquid crystal is between 0.5% and 36%.

[0079] TN liquid crystals offer various advantages compared to other liquid crystal technologies. For example, TN liquid crystals typically have extremely fast response characteristics and can adjust transmittance within a very short timeframe (e.g., 100 milliseconds or less). TN liquid crystals also provide good light blocking. For instance, the minimum transmittance of TN liquid crystals can be as low as 0.1%. Furthermore, because TN liquid crystals typically do not have suspended particles or polymers to scatter light, TN liquid crystal cells can introduce less haze and can improve visibility across a range of transmittance levels.

[0080] Furthermore, as described above, including a flexible substrate in the LC assembly may be advantageous. For example, substrate 702 and / or substrate 712 may include a transparent flexible material (e.g., PET or PVB). Thus, in some embodiments, the dimmable LC assembly includes: a flexible substrate, a liquid crystal layer comprising TN liquid crystal, and a polarizer layer. Additionally, such an LC assembly may include a rigid transparent layer (e.g., glass or PC) configured to serve as a structural support for the LC assembly and as a window. This rigid transparent layer may be an additional layer laminated together with or bonded to the flexible substrate (e.g., substrate 702 or substrate 712), and may have one or more intermediate layers (e.g., a connecting layer holding the rigid transparent layer together with the flexible substrate) between the rigid transparent layer and the flexible substrate. Thus, the rigid transparent layer may be integrally formed with the LC assembly. However, as referenced above... Figure 5A The LC component can also be manufactured separately, so that it can later be attached to the window as a thin film.

[0081] Figure 7C Another example configuration of the liquid crystal 714 is shown to provide adjustable light transmittance. Figure 7C In the liquid crystal cell 700, polarizer layers 726 and 728 are not included. Figure 7C In the example, the use of a polarizer is unnecessary because the liquid crystal 714 can be configured as a GH liquid crystal, comprising liquid crystal particles 740 acting as the host and dye particles 750 acting as the guest. The sizes of the liquid crystal particles 740 and dye particles 750 can vary and can comprise liquid crystal molecules and dye molecules. The light transmittance of the liquid crystal particles 740 and dye particles 750 can be modulated based on the guest-host effect. Specifically, the dye particles 750 can be configured to absorb light having an electric field perpendicular to the long axis of the dye particles. The liquid crystal particles in the GH liquid crystal can be nematic, and in some embodiments, in addition to the dye particles, chiral dopants can also be included. The chiral dopants twist the nematic liquid crystal particles (which act as the non-chiral host) into a helical structure in a manner similar to that of conventional TN liquid crystals.

[0082] exist Figure 7C In the middle, refer to the above. Figure 7AThe described friction pattern can have antiparallel friction directions to set the initial orientation of the liquid crystal particles and dye particles according to the operating mode of the liquid crystal cell. In the normally white mode where the liquid crystal cell is transparent when no electric field is applied, the friction direction can be configured such that the long axis of the dye particles is parallel to the electric field of the incident light 730 (e.g., ...). Figure 7C (As shown on the right), and the absorption of light by the dye particles can be set to a minimum. When an electric field is applied to the liquid crystal particles 740, the orientation of the liquid crystal particles 740 and the dye particles 750 can be changed accordingly. As a result, the portion of the incident light 730 absorbed by the dye particles 750 and the transmittance of the liquid crystal cell 700 can be adjusted by the electric field applied to the liquid crystal 714. On the other hand, in the normal dark mode, the rubbing direction can be configured such that the long axis of the dye particles is perpendicular to the electric field of the incident light 730 (e.g., as shown on the right), and the absorption of light by the dye particles can be set to a minimum. Figure 7C (As shown on the left), this results in maximum absorption of light 730 by the dye particles. When an electric field is applied to the liquid crystal, the absorption can be reduced by changing the orientation of the dye particles.

[0083] Figure 7B and Figure 7C The example configurations shown are not mutually exclusive. In some embodiments, the liquid crystal can be a TN liquid crystal (with a twisted structure) and a GH liquid crystal (with dye particles). For example, as described above, some embodiments may feature a GH liquid crystal, which includes chiral dopants to impart twist to the nematic liquid crystal particles.

[0084] By omitting the polarizer, GH-based LC components can increase the overall achievable transmittance while providing reasonable light-blocking performance. For example, using the guest-host effect, transmittance can range from 10% to 80%. Furthermore, GH liquid crystals can exhibit fast response characteristics and can adjust transmittance in a very short time. Moreover, like TN liquid crystals, GH liquid crystals do not require suspended particles (e.g., colloidal spheres) or polymer media to scatter light. Additionally, the color of the dye particles in GH liquid crystals can be selectively chosen to transmit specific colors of light while blocking other colors.

[0085] In some embodiments, the LC cell may include vertically aligned (VA) liquid crystals. In VA liquid crystals, the liquid crystal particles are vertical, meaning that they are aligned perpendicular to the substrate surface when no electric field is applied. The vertical liquid crystal particles can be rearranged to be parallel to the substrate surface by applying an electric field. VA liquid crystals typically have negative dielectric anisotropy. In some embodiments, the VA liquid crystal in the LC cell is a dual-frequency liquid crystal (DFLC), which has positive dielectric anisotropy at low frequencies and negative dielectric isotropy at high frequencies, and is referred to as dual VA. VA liquid crystals may also be GH liquid crystals in which dye particles are introduced.

[0086] Figures 8A to 8DVoltage-transmittance (VT) curves for some exemplary dimmable LC components are shown. Figure 8A In this example, the LC module comprises a TN liquid crystal configured in a normal white mode and has the following characteristics: voltage (V90) at 90% transmittance = 1.82V, pressure (V10) at 10% transmittance = 2.95V, cell gap = 6 micrometers (μm), twist angle = 60°, wavelength = 550 nanometers (nm), and frequency = 64 Hz. This frequency is the frequency of the electrical signal used to drive the LC module (e.g., to establish a voltage between the electrodes). The wavelength is the wavelength of the incident light, which is green light in this example. For a given voltage, the transmittance is generally stable, with a small degree of variability at the wavelength of interest (e.g., the visible spectrum). For example, from 400 to 700 nm, the transmittance can vary between approximately 20% and approximately 30%. Figure 8A As shown, the VT curve is relatively flat between 0 and 1.5V (approximately 30% of maximum transmittance), and then slopes downwards towards the minimum transmittance of approximately 0.1% at approximately 4V.

[0087] exist Figure 8B In this example, the LC module includes a GH liquid crystal configured in normal white mode and has the following characteristics: V90 = 1.8V, V10 = 3.7V, cell gap = 9μm, twist angle = 360°, wavelength = 550nm, and frequency = 64Hz. Figure 8B As shown, with Figure 8A In comparison, the VT curve is significantly steeper. Due to the steeper VT curve, Figure 8B The LC components may require more precise control over the applied electric field, particularly the voltage on the sloping portions of the curve. However, configuring the control module (e.g., Figure 6A It is feasible to implement this control using a control module 630. For example, the control module 630 can look up a table stored in the memory of the control unit 600, where the table maps different voltage points to their corresponding transmittance levels. Figure 8A Compared to the lookup table configured in the middle, Figure 8B The lookup table configured in the module may include a finer voltage gradient. Alternatively, in some embodiments, the control module may be programmed or otherwise configured as a nonlinear function with an approximate VT curve of the actual LC component. Figure 8A configuration and Figure 8B Another performance difference between the configurations is Figure 8B The minimum transmittance level is higher.

[0088] exist Figure 8CIn this design, the LC module includes a GH liquid crystal (dual VA) configured in normal white mode, and has the following characteristics: V90 = 2.24V, V10 = 5.5V, cell gap = 9μm, twist angle = 0°, wavelength = 550nm, and frequency = 64Hz. Figure 8A and 8B Compared to the configuration in the middle, Figure 8C The dual VA configuration in the middle provides more than Figure 8A and Figure 8B Higher maximum transmittance, and with Figure 8B The minimum transmittance is roughly the same.

[0089] Figure 8D Another VT curve based on a GH configuration is shown. Figure 8D In this LC module, there is a GH liquid crystal configured in a normal white mode, and it has the following characteristics: V90 = 1.72V, V10 = 3.1V, cell gap = 9μm, twist angle = 360°, wavelength = 550nm, and frequency = 64Hz. Figure 8D The VT curve in the middle is similar to Figure 8B The curve in the figure, but characterized by a slightly higher maximum transmittance level.

[0090] Figures 9A to 9C An example of an LC component including a PVB layer is shown according to some embodiments. Figures 9A to 9C The LC component shown can be formed into a laminated structure using appropriate levels of heat and pressure. Figure 9A In the LC component 900, from top to bottom, there are a first glass layer 902, a first PVB layer 904, a PET layer 906, a second PVB layer 908, a first TAC-protected polarizer 910, a first optically transparent adhesive (OCA) layer 912, a first PC layer 914, a first ITO layer 916, a third PVB layer 928, and a second glass layer 930.

[0091] When the LC component 900 is configured as an automotive sunroof, the example thicknesses of some of the aforementioned components (total thickness approximately 6100 μm) are as follows:

[0092] • Glass layers 902 and 930: 2 mm each

[0093] • PVB layers 904, 908, and 928: each 380μm.

[0094] • PET layer 906: 105 micrometers,

[0095] • Polarizers 910 and 926 protected by TAC: 170μm each,

[0096] • OCA layers 912 and 924: each 50μm

[0097] • PC layers 914 and 922: 105μm each

[0098] • Sealant 918 (same as LCD 940): 9 microns to 15 microns, and

[0099] • ITO layers 916 and 920: 4 micrometers each.

[0100] Each of the TAC-protected polarizers 910 and 926 can include a polarizer protected by one or more TAC layers. Therefore, although shown as a single layer, each of the TAC-protected polarizers 910 and 926 can correspond to a layered structure comprising a polarizer plate plus a TAC layer on at least one surface of the polarizer plate. Polarizing plates are susceptible to damage during handling. Applying TAC to the polarizer plate helps prevent such damage and isolates the polarizer plate from environmental influences. Furthermore, in some embodiments, the polarizer may include a UV-blocking material. For example, a TAC-protected polarizer may sequentially include the following layers: a first TAC layer, a polarizer plate, a second TAC layer, and a UV-protective coating that filters UV light. Alternatively, the UV-blocking material may be incorporated into the material of the TAC layers.

[0101] The LC assembly 900 also includes a spacer 938, a liquid crystal 940, and an electrical connector 950. The spacer 938 can correspond to... Figure 7A The spacer 708 in the middle. The liquid crystal 940 can correspond to Figures 7A to 7C One of the configurations of the liquid crystal 714 (e.g., TN or GH liquid crystal). The electrical connector 950 is configured to transmit signals to a pair of electrodes. Figure 9A In this context, the electrodes correspond to ITO layers 916 and 920. An electric field can be established via signals transmitted through electrical connector 950, which can be connected to a control unit (e.g., via a cable). Figure 6A (Control unit 600 in the LC assembly). Additionally, the LC assembly 900 may include circumferential or edge seals (not shown) that operate against gaskets of glass layers 902 and 930, as referenced above. Figure 7A The circumferential seal may be located at region 952 and may be wound around the periphery of LC assembly 900.

[0102] The PET layer 906 corresponds to the flexible substrate and may include IR protection. For example, the PET layer 906 may be formed with an IR-blocking additive or coated with an IR-blocking material layer. IR blocking can be useful in automotive applications, especially in sunroofs, as blocking IR radiation helps prevent overheating. In some embodiments, the PET layer 906 may be replaced with a different flexible material (e.g., PC or TAC), which may also have IR protection. For applications where IR protection is not required, it can be omitted to avoid reduced light transmittance.

[0103] OCA layers 912 and 924 may be formed by a transparent adhesive. In some embodiments, OCA layers 912 and 924 are formed using liquid OCA (LOCA), which is sprayed onto PC layers 914, 922 and / or TAC-protected polarizers 910, 926 in preparation for lamination.

[0104] PC layers 914 and / or PC layer 922 can be formed of flexible polycarbonate and can correspond to substrates 702 and 712. Therefore, PC layers 914, 922 and PET layer 906 can be formed as flexible films. ITO layers 916 and 920 correspond to conductive layers on the substrates on which PC layers 914 and 922 are formed, respectively. PC layers 914 and 922 provide mechanical support for ITO layers 916 and 920, which define the top and bottom walls of the LC cells filled with liquid crystal 940. The LC cells are laminated or bonded to glass layers 902 and 930. Although glass layers 902 and 930 are shown as flat, in reality, glass layers 902 and 930 may not be perfectly equidistant at all points along their surfaces (this may also be true when glass layers 902 and 930 are designed to have the same curvature). To compensate for such defects, PVB layers 904, 908, and 928 can be heated to melt, thereby covering the defects (gap filling). Once cooled, the PVB layers solidify to hold the layers adjacent to PVB layers 904, 908, and 928 together. This helps to avoid uneven pressure distribution when the constituent layers of the LC assembly 900 are subjected to pressure during lamination. In some embodiments, PVB layers 904, 908, and 928 can be replaced with different adhesives / plastics, such as ethyl acetate (EVA), PET, acrylic, epoxy, silicone-based adhesives, or some other optically clear adhesives (e.g., the same material as OCA layer 912 or OCA layer 924). Furthermore, in some embodiments, one or more TAC layers, such as the TAC portions of polarizers 910 and 926 protected by TAC, can be formed as a flexible substrate. Therefore, a flexible LC assembly can include one or more flexible layers, one or more of which have the same or different materials.

[0105] Figure 9B An LC component 980 according to one embodiment is shown. Similar elements are used with... Figure 9A The same reference numerals are used to mark them. Figure 9B In this embodiment, the PVB layer 904 and PET layer 906 are replaced by an IR coating 960 used as an IR filter. The IR coating 960 can be formed by sputtering an IR blocking material onto the glass layer 902.

[0106] Figure 9CAn LC component 990 according to one embodiment is shown. Similar elements are used with... Figure 9A The same reference numerals are used for identification in the accompanying drawings. LC component 990 does not include... Figure 9A PET layer 906 or Figure 9B The IR coating 960 is applied. Therefore, the LC component 990 may not provide IR protection.

[0107] When the LC component 990 is configured as an automotive side window, the example thicknesses of some of the aforementioned components (total thickness approximately 5600 μm) are as follows:

[0108] • Glass layers 902 and 930: 2 mm each,

[0109] • PVB layer 908: 380 micrometers

[0110] • Polarizers 910 and 926 protected by TAC: 170μm each,

[0111] • OCA layers 912 and 924: each 50μm

[0112] • PC layers 914 and 922: 105μm each

[0113] • Sealant 918 (same as LCD 940): 9 microns to 15 microns, and

[0114] • ITO layers 916 and 920: 4 micrometers each.

[0115] As mentioned above, flexible LC components are advantageous, especially when used in conjunction with curved rigid substrates (e.g., curved automotive windows). However, flexible LC components are sensitive to uneven pressure distribution and stress. Therefore, techniques for uniformly distributing pressure or stress during lamination will help avoid damage to the flexible LC components. As mentioned above, melting PVB or some other adhesives to fill the gaps between surfaces is one way to ensure uniform pressure distribution.

[0116] Another challenge with flexible LC modules is the temperature-dependent behavior of the flexible substrate (e.g., PC / PET / TAC substrate), the liquid crystal, and the rigid substrate (e.g., glass). All three can have different coefficients of thermal expansion. For example, the coefficient of thermal expansion of a flexible substrate can be higher than that of a glass panel (e.g., two glass panels forming the outer layer of an LC module, where LC cells with a flexible substrate are laminated between the glass panels). Furthermore, liquid crystals can have a higher coefficient of thermal expansion than flexible substrates. Therefore, when subjected to temperature changes as part of the lamination process (e.g., heating the LC module in an oven), liquid crystals, due to their higher coefficient of thermal expansion, may experience greater expansion compared to flexible substrates, potentially leading to damage.

[0117] Temperature changes can also occur outside of manufacturing. For example, certification testing for automotive windows includes temperature shock testing, where the temperature changes rapidly over a short period (e.g., 1 minute), such as from 70°C or higher to -20°C or lower. Such rapid temperature changes can generate high stresses in the LC assembly or on any number of components associated with it, such as the adhesive, flexible substrate, or the frame housing the LC assembly, leading to breakage. To address the issue of different thermal expansion between layers, lamination arrangements are provided in some embodiments. Lamination arrangements include one or more adhesives that have the ability to form a strong bond while possessing sufficient flexibility to allow thermal expansion without breaking down over numerous thermal expansion cycles (e.g., hundreds of thousands of cycles). Furthermore, as combined below... Figure 19 Some embodiments may include expansion joints to allow for expansion and contraction space after the LC assembly, for example, is mounted to a vehicle body. The expansion joint feature can be used in conjunction with flexible adhesives to prevent damage due to differences in coefficients of thermal expansion.

[0118] Furthermore, as mentioned above, the PVB-based processes used in automotive safety glass traditionally require high temperatures (~140°C) and high pressures (~12 to 15 bar). Such temperatures and pressures can typically damage LC modules (e.g., damaging spacers and polarizer layers). To prevent damage to LC modules, the maximum temperature and pressure they can withstand during manufacturing can be limited. The maximum temperature that LC modules can withstand can be limited to about 100°C to 160°C (preferably between 110°C and 120°C). The maximum pressure can be set to about 1 to 4 bar, or 10 to 15 bar when mechanical pressure is applied.

[0119] In some embodiments, LC components including PVB (e.g., Figures 9A to 9C The LC component shown is capable of successful lamination using a technology. This technology includes an environmental-side solution achieved by controlling the environment in which lamination / bonding is performed, and an LC-side solution achieved through the appropriate design of the LC component and its components.

[0120] In some embodiments, the spacer (e.g., spacer 938) is formed of a high-temperature resistant material. Additionally or alternatively, the spacer may be formed with a geometry resistant to high pressure. For example, instead of forming spacer 938 as a sphere, spacer 934 may be formed as a rectangular block, a cylinder, or some other geometry that is more resistant to deformation. For example, in Figure 9A In this process, spacer 938 can be replaced by a plastic cylinder (e.g., a circular or elliptical cylinder) whose substrate contacts ITO layers 916 and 920. Besides the spacer, other components of the LC assembly, such as the polarizer, can be formed from high-temperature resistant materials to ensure the LC assembly survives the lamination process.

[0121] In some embodiments, the spacers and / or contact spacers are coated to make the substrate more resistant to damage caused by applied high pressure, such as when the spacers penetrate the substrate. For example, the spacers 938 and / or ITO layers 916, 920 may be coated with a transparent material having a greater hardness than the PC layers 914, 922. Alternatively, the material of the spacers and / or contact spacers may be tempered to strengthen the material.

[0122] Figure 10 An example of a system for laminating an LC component 1000 including PVB, according to some embodiments, is shown. Figure 10 In the process, when the LC assembly 1000 is located in a vacuum bag or chamber 1020, the lamination of the LC assembly 1000 includes the application of heat and pressure. Figure 10 The LC component 1000 shown is a simplified representation of an LC component and is shown as including a first substrate 1002, a first PVB layer 1004 between the first substrate 1002 and the LC unit 1006, a second substrate 1010, and a second PVB layer 1008 between the LC unit 1006 and the second substrate 1010. However, the LC component 1000 can represent any LC component containing PVB. The LC unit 1006 can include any liquid crystal described herein, such as TN liquid crystal, GH liquid crystal, or VA liquid crystal, and may or may not have chiral dopants.

[0123] One purpose of the lamination process is to form a stacked, multi-layered structure in which the stacked layers are held firmly together with minimal air bubbles or gaps between the layers. Figure 10 Bubbles 1012 are shown between substrate 1002 and PVB layer 1004, and between substrate 1010 and PVD layer 1008. As described above, these bubbles are formed due to variations in the height of the substrate surface. Pressure is applied to force the bubbles out, and this pressure is conventionally applied mechanically, for example, by clamping the layers together using relatively high pressure. Therefore, in some embodiments, mechanical pressure is applied to force air out of the multilayer structure (e.g., from the center of the multilayer structure to the outer edges). However, as... Figure 10 As shown, a vacuum chamber or vacuum bag allows for the removal of air bubbles using relatively low pressure. Therefore, mechanical pressure can be replaced by atmospheric pressure generated by using a vacuum environment.

[0124] PVB layer 1004 and PVB layer 1008 correspond to the adhesive layers that bond substrates 1002 and 1010 to LC cell 1006. PVB layer 1004, PVB layer 1008, substrate 1002, and / or substrate 1010 can be configured to allow air to escape when pressure is applied. For example, the surface of PVB layer 1008 in contact with substrate 1002 may include channels (e.g., microgrooves with a width smaller than the diameter of bubble 1012) that allow air movement, wherein these channels are eliminated by melting of PVB layer 1006. Similarly, substrate 1002 may include channels filled with molten material from PVB layer 1004. Figure 10 This is merely an example illustrating the lamination process used to form LC components using stacked layers. In some embodiments, PVB layers 1004 and 1008 can be replaced with another material that is melted to adhere the two layers together, such as... Figure 9A The OCA layers 912 and 924 in the OCA layer are made of the same OCA material.

[0125] The vacuum environment provided by the vacuum bag / chamber 1020 removes air bubbles 1012. The vacuum bag / chamber 1020 also enables lamination at lower pressures and under lower pressures. For example, if the LC assembly 1000 is placed in the vacuum chamber, the pressure can be set to approximately 1 to 2 bar (1 bar equals 100,000 Pascals), and the temperature can be set to approximately 110°C (the vacuum chamber can also be used as a convection furnace or autoclave) to melt the PVB layers 1004 and 1008. Depending on the degree of melting of the PVB layers (e.g., complete melting versus melting to a certain depth), a temperature of approximately 110°C can be maintained for a set duration. Upon cooling, the PVB layers 1004 and 1008 will re-solidify, and the entire LC assembly 1000 can then be removed from the vacuum chamber. The temperature and pressure inside the vacuum bag / chamber 1020 can be monitored using a temperature sensor 1030 and a pressure gauge 1032. The temperature and pressure can be set via a controller 1040 connected to the temperature sensor 1030 and the pressure gauge 1032.

[0126] Compared to vacuum chambers, vacuum bags have lower setup and operating costs, but typically require higher temperatures and pressures. For example, to laminate an LC assembly 1000 using a vacuum bag, air can be evacuated from the vacuum bag through pipe 1022 until a pressure of approximately 3 to 4 bar is reached. At a pressure of 3 to 4 bar, the LC assembly 1000 can be heated to approximately 120°C (e.g., by placing the vacuum bag in an oven) to melt the PVB layers 1004 and 1008. The vacuum bag itself can be formed from a heat-resistant material, allowing it to be reused. Therefore, the pressure can be set between 1 and 4 bar, with higher pressures typically set when using a vacuum bag than when using a vacuum chamber.

[0127] Despite the above combination Figure 10 The lamination technique described can be used to reduce temperature and pressure, but completely avoiding PVB may be beneficial. Figure 13 The expansion of the LC panel 1300 during lamination with the PVB panel 1310 and the glass panel 1320 is shown. Figure 13 As shown, the LC panel 1300 expands upon heating (indicated by solid arrows) and then contracts upon cooling (indicated by dashed arrows), creating wrinkles 1350. Furthermore, because the LC panel 1300 is bonded to the PVB panel during cooling, the contraction of the LC panel 1300 is restricted, generating stresses that can lead to damage, such as breakage of the bond around the edge seal (not shown). The glass panel 1320 may also be subjected to stress, resulting in an uneven pressure distribution, which may cause visual artifacts or patterns due to the liquid crystal not being uniformly distributed throughout the LC panel 1300. Such artifacts are particularly noticeable in the minimum transmission (dark) state.

[0128] Therefore, applications such as Figure 10 The technology involves processes to form laminated LC modules comprising glass and PVB layers. However, due to the complexity of implementing such a process, it may be advantageous to use materials other than PVB to bond the LC panel to the substrate, for example, replacing the PVB layer with OCA, as described above. Instead of the PVB layer, adhesives including OCA, silicone, resins, etc., can be used to bond the LC panel. The adhesive can be film-based or liquid-based. For example, there are adhesives with extremely low viscosity (e.g., below water) that are suitable for filling gaps the size of air bubbles, and which can cure relatively quickly, for example, within minutes at an ambient temperature of 20 to 30 degrees Celsius. Furthermore, as described below, some embodiments may feature a combination of film-based adhesives and liquid adhesives. In some cases, curing of the PVB substitute can be carried out without the application of heat or pressure, and in embodiments without a UV blocking layer, rapid curing can be achieved using UV light. Alternative adhesive materials such as OCA, silicone, or resins may offer advantages beyond the manufacturing process itself. For example, PVB substitutes can maintain functionality over a wider temperature range (e.g., at temperatures higher than that PVB can sustain) and can have higher transmittance than PVB, thereby minimizing the impact on the overall transmittance of the LC module.

[0129] The optical performance of LC components can be improved by selecting an adhesive with at least 99% transmittance and refractive index, whose refractive index at least partially matches that of the substrate to which the LC unit is bonded, in order to minimize transmission losses. The desired refractive index of the adhesive can be calculated based on the Fresnel model. For p-polarized light (whose electric field is parallel to the plane of incidence), the transmittance coefficient τ through the boundary between the two media k and k-1 is... pThe Fresnel equations, where k⁻¹ is the incident medium and k is the transmitting medium, are given by the following equation:

[0130]

[0131] Similarly, the transmission coefficient τ n For s-polarized light (whose electric field is perpendicular to the plane of incidence), it is given by the following equation:

[0132]

[0133] For example, applying Fresnel's equations for s-polarized light to each of the six boundaries in the example LC assembly described in the table below yields a total transmittance of 79% (τ). n =0.79) When the refractive index of the ITO layer matches (is substantially equal to) the refractive index of the PC substrate, the transmission loss through the PC substrate and the GH liquid crystal is considered. In this example, the refractive index of the PC substrate is 1.586, and the refractive index of the ITO layer is 1.54 in the matched case and 1.9 in the mismatched case. When the ITO refractive index is mismatched, the overall transmittance is 78%. Depending on the degree of matching, the overall transmittance can be between 80% and 76%.

[0134]

[0135] For automotive applications, laws in most countries require windshields and front side windows to have a transmittance of 70% or higher. Therefore, to avoid reducing the total transmittance below 70% after adding one or more adhesive layers, the materials of the adhesive and at least some layers in the LC assembly (e.g., ITO layers and substrate) can be selected to have matching or closely matched refractive indices.

[0136] In some implementations, such as the examples in the table above, glass can be replaced with PC. Other materials that are more flexible and / or lighter than glass, such as PET, can also be used. (Return to Reference) Figures 9A to 9C The PC layer (914922) can form the substrate of the LC cell. Traditional LC cells consist of a sandwich structure containing liquid crystal between two glass substrates. Compared to glass, replacing glass with PC improves the impact resistance of the LC module and allows for a degree of flexibility; glass is rigid but does not sacrifice transparency or optical clarity. Typically, any glass layer in an LC module can be replaced with a PC layer. For example, PC can replace glass layer 902 and / or glass layer 930. The PC layer is not limited to LC modules integrally formed with a window and can also be included in LC modules designed to be attached to a window.

[0137] When used as an outer layer (e.g., replacing glass layer 902 or glass layer 930), PC is softer than glass, so the surface of the PC layer can be coated with a scratch-resistant material to prevent abrasion. Due to its impact resistance and ability to be formed into many different shapes, PC can be bonded to one or more layers to form LC assemblies suitable for automotive windows (e.g., side windows). PC is also lighter than glass, reducing the weight of the LC assembly and thus the overall weight of the vehicle. For example, replacing glass windows with PC windows can reduce a car's weight by approximately 50 pounds, which can improve fuel / battery economy.

[0138] Figure 11 It shows the application from Figure 7A The UV curing step of the LC unit 700. Figure 11 In this process, UV light 1130 is applied to both sides of the LC cell 700, causing the UV light to strike the outer surfaces of the substrates 702 and 712. In some embodiments, only one side of the LC cell is illuminated, and this may be sufficient to allow the UV light to pass through the other side of the LC cell. When the UV light 1130 enters the LC cell, the UV light cures the UV adhesive 1102 that contacts the substrate-facing surface of the sealant 706. Once the adhesive 1102 has cured, the substrates 702 and 712 become firmly attached to the sealant 706.

[0139] If substrates 702 and 712 are replaced by UV-blocking materials, UV light 1130 will not be able to reach adhesive 1102, or UV light 1131 will be blocked to the extent that the portion of UV light 1132 penetrating the UV-blocking material will not be sufficient to completely cure adhesive 1102. Similarly, if one or more UV-blocking layers are introduced between the substrate and the UV adhesive, the UV adhesive will not be able to be cured by UV light.

[0140] UV-based adhesives are frequently used in the automotive industry. One advantage of UV adhesives is that parts to be bonded together can be repositioned at any time before UV curing. If parts are misaligned or incorrectly positioned, they can be easily moved before curing. However, as mentioned above, UV adhesives are incompatible with UV-blocking materials. Furthermore, some types of LC components depend on the use of one or more UV-blocking materials. For example, in applications such as... Figure 7B In the TN LC cell shown, the polarizer is used to control the direction of light entering or leaving the liquid crystal. (As described above...) Figure 9A The polarizer discussed can be protected using TAC and may also include a UV protective coating. Therefore, UV curing may not be possible for TN LC cells or other LC cells that include polarizers.

[0141] Due to the UV-blocking properties of the UV-protective coating typically included in TAC-protected polarizers, such polarizers have not yet been used in conjunction with LC assemblies traditionally bonded using UV adhesives. For example, Figure 11 The electrodes 704 and 710 in the LC assembly can be formed using ITO or other materials suitable for bonding with UV adhesives. Therefore, conventional LC assemblies lack TAC-protected polarizers bonded to ITO-based electrodes. Instead, Figure 12A and Figure 12B An example is shown, featuring a polarizer protected by TAC combined with an ITO-based electrode.

[0142] Figure 12A An LC assembly 1200 according to one embodiment is shown. The LC assembly 1200 includes, from top to bottom, a first glass layer 1202, a first OCA layer 1204, a first TAC-protected polarizer 1206, a second OCA layer 120, a first PC layer 1210, a first ITO layer 1212, a sealant 1214, a second ITO layer 121, a second PC layer 1218, a third OCA layer 1220, a second TAC-protected polarizer 1222, a fourth OCA layer 1224, and a glass layer 1226.

[0143] exist Figure 12A In this configuration, the TAC-protected polarizer 1206 is bonded to the glass layer 1202 via the OCA layer 1204 and to the PC layer via the OCA film 1208. Similarly, the TAC-protected polarizer 1222 is bonded to the glass layer 1226 via the OCA layer 1224 and to the PC layer 1218 via the OCA film 1220. Figure 12A Each OCA layer shown can be liquid OCA. Furthermore, the TAC-protected polarizers 1206 and 1222 can each include a UV-protective coating.

[0144] ITO layers 1212 and 1216 correspond to electrodes. However, the electrodes of the LC assembly according to the embodiments described herein can be formed of another conductive material, such as graphene.

[0145] Figure 12B An LC component 1290 according to one embodiment is shown. The LC component 1290 includes components with... Figure 12A Similar to the LC component 1200, but with PC layers 1210 and 1218 omitted. Without these PC layers, TAC-protected polarizers 1206 and 1222 are directly attached to ITO layers 1212 and 1216, respectively. Therefore, in some embodiments, the ITO layer can be formed directly on the TAC-protected polarizer or any other layer including the TAC. For example, ITO layer 1212 can be directly sputtered onto the TAC portion of the TAC-protected polarizer 1206.

[0146] To enable LC components to include UV-blocking elements, such as TAC-protected polarizers, aspects of this disclosure relate to alternatives to UV adhesives. In particular, embodiments relate to the use of non-UV-curable adhesives such as epoxy resins and heat-activated adhesives. For example, Figure 11 The adhesive 1102 in the process can be replaced with a two-part epoxy resin with a relatively long working time. The working time of the epoxy resin can be, for example, a few minutes long, as this is usually sufficient to prepare the LC assembly for lamination, but allows for a small time window for repositioning the parts as needed. Alternatively, a heat-activated adhesive that cures at or below the lamination process temperature can be used.

[0147] Figure 14 An LC component 1400 according to some embodiments is shown. As described above, for example, regarding Figure 12A and 12B The OCA layer in the LC assembly allows liquid adhesive to be bonded to the LC unit, enabling bonding of the LC unit to a glass plate or other substrate, potentially serving as an alternative to bonding via PVB. Figure 14 In one example, the LC assembly 1400 includes an LC unit 1410, which is bonded to an outer substrate 1420 and an inner substrate 1430 by a combination of a liquid adhesive 1440 and a film-based adhesive 1450.

[0148] As this article combines Figure 14 As used in the following figures, when the LC assembly is mounted as a window, the outer substrate refers to the substrate closest to the external environment. Similarly, the inner substrate refers to the substrate closest to the internal environment. In an automotive environment, this substrate is typically glass. For simplicity, Figure 14 The various figures that follow depict the LC cell as a single layer. However, as mentioned above, the LC cell may include layers other than the liquid crystal layer. Therefore, the LC cell 1410 may include a stack forming a panel, which includes, for example, a polarizer, an intermediate substrate, a moisture barrier layer, and / or an IR or UV barrier layer.

[0149] Liquid adhesive 1440 is applied to the surface of LC cell 1410 facing the outer substrate 1420, and upon curing, it bonds LC cell 1420 to the outer substrate 1420. Figure 14 As shown, liquid adhesive 1440 can extend to contact the inner substrate 1430. Liquid adhesives such as adhesive 1440 can be used to fill the gap between the LC cell and a glass or other (e.g., PC) substrate. Although Figure 14The outer substrate 1420 and inner substrate 1430 are shown as flat, but in practice, small variations in height may exist on the surfaces of substrates 1420 and 1430, resulting in unevenness in the distance 1405 between substrates 1420 and 1430. Height variations are particularly common when the substrates are bent, such as in car windows, because it is difficult to precisely form the curvature. Although molten adhesives such as PVB can be used to bond LC cells to the substrate, when in a solid state (e.g., after melting), molten adhesives tend to exert pressure on the LC cells. Height variations can cause the molten adhesive to exert this pressure unevenly, especially if the molten adhesive does not completely melt before cooling, causing deformation of the LC cells, resulting in visual artifacts or other undesirable optical properties. For example, in a dark state, an LC cell may have some areas that are darker than others. Furthermore, liquid adhesives can remain flexible after curing, allowing for thermal expansion and contraction, thus avoiding pressure points.

[0150] The film-based adhesive 1450 is a solid adhesive that bonds the LC unit 1410 to the inner substrate 1430, and can be applied before applying (e.g., by injection) a liquid adhesive 1440 to hold the LC unit 1420 in position relative to the inner substrate 1430. Similar to the liquid adhesive 1440, the film-based adhesive 1450 can be sufficiently flexible to allow for thermal expansion and contraction. The film-based adhesive 1450 can be carried on a transparent, flexible film. For example, the film-based adhesive 1450 can be coated on both sides of a plastic film to allow one side of the plastic film to be attached to the LC unit 1410 and the other side to the inner substrate 1430, wherein the plastic film forms part of the LC assembly. Alternatively, the film-based adhesive 1450 can be disposed on a temporary film that is peeled off to leave no film between the LC unit 1410 and the inner substrate 1430.

[0151] The LC assembly 1400 also includes one or more edge seals 1460. In some embodiments, a single edge seal extends around the periphery of the LC assembly to prevent the penetration of moisture and contaminants. For example, the edge seal 1460 may be a gasket ring formed using a synthetic rubber such as butyl. However, the edge seal does not need to cover the entire periphery. For example, the LC assembly may include four edge seal strips, one on each side of the LC assembly, such that the periphery is collectively covered by the edge seals. Furthermore, as... Figure 15 As shown (as described below), the edge seal can be bonded to the substrate of the LC assembly using, for example, an adhesive. Other materials can also be used for the edge seal. In some embodiments, the edge seal 1460 can be made of... Figures 7A to 7C The sealant 706 is formed from similar materials, such as plastics, elastomers, or other relatively soft materials, such as PET.

[0152] Figure 15 The diagram illustrates the shear stress generated in the LC assembly 1500 when it is placed against surface 1505 (e.g., the ground). The LC assembly 1500 can be placed on surface 1505 before installation, such as during storage or transport. Similar to... Figure 14 The LC assembly 1400 and LC assembly 1500 include LC units 1510 bonded to the outer substrate 1520 and the inner substrate 1530 by a combination of liquid adhesive 1540 and film-based adhesive 1550.

[0153] The LC assembly 1500 also includes an edge seal 1560 that extends around the periphery of the LC assembly 1500 to prevent the penetration of moisture and contaminants. The edge seal 1560 is similar to... Figure 14 The edge seal 1460 is located at the edge 1508 of the LC assembly, in the space formed by the outer substrate 1520 and the inner substrate 1530 extending beyond the boundary of the LC cell 1510.

[0154] Liquid adhesive 1540 and film-based adhesive 1550 can have wide operating temperature ranges, for example, maintaining a stable yet flexible bond between -40°C and +115°C, and relatively short curing times (e.g., 1 to 5 minutes for both adhesives). In some embodiments, at least one of adhesives 1540 and 1550 is acrylic-based. In the case of LC components, acrylic is a suitable adhesive because it is color-stable and does not yellow over time. Because acrylic-based adhesives are sensitive to moisture, portions of LC components bonded using acrylic-based adhesives can be protected against moisture through edge seals such as edge seals 1560.

[0155] Edge seal 1560 is bonded to substrates 1520 and 1530 by adhesive 1562, which may be a resin-based adhesive or another adhesive with relatively high bonding strength compared to liquid adhesive 1540 and film-based adhesive 1550. Adhesive 1562 may have a wide operating temperature range similar to liquid adhesive 1540 and film-based adhesive 1550, for example, between -40 degrees Celsius and +115 degrees Celsius. Furthermore, adhesive 1562 may be moisture-resistant and remain stable over many years of operation (e.g., at least 15 years). For automotive applications, adhesive 1562 may be a non-silicone-based adhesive. To prevent damage during the operation or installation of the LC assembly 1500, the material of edge seal 1560 may be selected to have a coefficient of friction less than or equal to that of substrates 1520 and 1530 (e.g., the same coefficient of friction as glass). A high coefficient of friction may cause force to concentrate at the edge seal 1560 instead of being evenly distributed across the edge seal 1560 and the substrates 1520 and 1530, thereby causing damage to the LC unit 1510.

[0156] like Figure 15 As shown, the LC assembly is located at one corner of edge 1508. Since edge 1508 of the LC assembly 1500 is not fully supported by surface 1505 at this location, the weight of the substrate not in contact with the surface (in this example, inner substrate 1530) pulls in the direction of gravity. The effect of this gravity, combined with the force of the surface 1505 pushing in the opposite direction, can cause shear stress, which can lead to damage or delamination of the LC unit 1510. For example, shear stress can overcome the strength of the adhesive 1562 around edge seal 1560, causing liquid adhesive 1540 to leak through edge seal 156 and creating voids positioned along the periphery of the LC assembly and having a cracked appearance. The glass substrate is particularly heavy. To reduce the weight of the substrate and thus the amount of shear stress, at least one substrate can be made thinner, such as… Figure 16 As shown.

[0157] Figure 16 An LC assembly 1600 is shown attached to a mounting body 1612 according to some embodiments. The mounting body 1612 is typically a rigid structure supporting the LC assembly 1600 and may, for example, be a vehicle roof. The LC assembly 1600 includes components... Figure 15 Components similar to those depicted include, for example, the LC unit 1610, outer substrate 1620, inner substrate 1630, liquid adhesive 1640, film-based adhesive 1650, and edge seal 1660. Figure 16 In the example, the inner substrate 1630 is substantially thinner than the outer substrate 1620 in order to reduce the thickness of the bonding layer. Figure 15The shear stress is described. The outer substrate 1620 can also be manufactured thinner. However, for safety reasons, the thickness of the outer substrate is typically limited. For automotive applications, the outer substrate 1620 ranges from approximately 2 mm to 3.5 mm, the inner substrate 1630 ranges from 0.7 mm to 2 mm, and the total thickness of the entire LC assembly is approximately 5 mm or less. Figure 16 As shown, the outer substrate 1620 extends past the edge seal 1660 to be received in the recess 1605 of the mount 1612. Here, the thickness of the outer substrate 1620 helps the LC assembly 1600 to be firmly and securely attached to the mount 1612. Since the weight of the LC assembly 1600 is borne by the outer substrate 1620, the more fragile inner substrate 1630 is protected from damage. Furthermore, since both substrates 1620 and 1630 are supported on the mount 1612, shear stress is generally not generated once the LC assembly is installed.

[0158] Figure 17 An LC assembly 1700, attached to a mounting body 1712 according to some embodiments, is shown. Apart from the addition of a gasket 1705, the LC assembly 1700 and... Figure 16 The LC assembly 1600 is identical to that in the external substrate 1620. In conjunction with the external substrate 1620, the gasket 1705 provides a flat surface for flush mounting the LC assembly 1700 to the mounting body 1712. Figure 17 In this example, the weight of the LC assembly 1700 is borne by both the outer substrate 1620 and the gasket 1705. The gasket 1705 may be formed of the same or similar material as the edge seal 1660, and is combined as described above. Figure 15 As illustrated in the example, the coefficient of friction of the pad 1705 may be less than or equal to the coefficient of friction of the substrates 1620 and 1630.

[0159] Figure 18 An LC assembly 1800, attached to a mounting body 1812 according to some embodiments, is shown. The LC assembly 1800 is similar to... Figure 15 In the LC assembly 1500, the outer substrate 1820, inner substrate 1830, and edge seal 1860 each extend to the edge of the LC assembly. Therefore, the weight of the LC assembly 1800 is borne by the outer substrate 1820, inner substrate 1830, and edge seal 1860. Similar to the LC assembly 1600, the inner substrate 1830 is thinner than the outer substrate 1820. Depending on the weight of the LC assembly 1800, although the inner substrate 1830 is thinner than the outer substrate 1820, it can be strong enough to support it. Figure 18 The LC assembly 1800 is shown in the configuration. Thinning of the internal substrate can also be applied to other mounting configurations, including configurations where the LC assembly is oriented at the ground-facing edge, such as in a car side window.

[0160] Figure 19 An LC assembly 1900 configured to accommodate thermal expansion and contraction according to some embodiments is shown. The LC assembly 1900 is similar to the LC assembly 1600 and includes an LC unit 1910, an outer substrate 1920, an inner substrate 1930, and an edge seal 1960. However, the edge seal 1960 is spaced apart from the LC unit 1910 by a first gap 1902. Furthermore, the edge seal 1960 and the inner substrate 1930 are spaced apart from a mounting body 1912 in a mounting configuration to define a second gap 1904. In some embodiments, gaps 1902 and 1904 may be approximately 1 mm wide. Both gaps 1902 and 1904 are filled with a flexible sealant to serve as expansion joints accommodating the thermal expansion and contraction of the LC unit 1910. The LC unit 1910 may have a different coefficient of thermal expansion than the substrate. For example, the outer layer of the LC unit may be plastic, while the substrates 1920 and 1930 may be glass, such that the LC unit expands more than the substrate in response to heat. Therefore, temperature changes can cause the LC cell 1910 to expand or contract relative to the substrate.

[0161] Similar to Figure 14In the example, the LC assembly 1900 includes a liquid adhesive 1940 and a film-based adhesive 1950. In some embodiments, the flexible sealant in at least one of the gaps 1902 and 1904 is a non-adhesive sealant. For example, the sealant in gap 1902 may be a liquid adhesive similar to liquid adhesive 1940 or a film-based adhesive similar to film-based adhesive 1950, while the sealant in gap 1904 may be a non-adhesive sealant to prevent the edge seal 1960 and / or the inner substrate 1930 from adhering to the mounting body 1912. The liquid adhesive 1940, film-based adhesive 1950, and sealant in gaps 1902 and 1904 can compensate for differences in coefficients of thermal expansion by remaining flexible over a wide temperature range (e.g., -40°C to +115°C) to allow the LC panel to expand and contract. In the absence of such flexible components, stress buildup can lead to tearing or delamination of the LC cell. The sealant-filled gap 1902 acts as a buffer between the edge seal 1960 and the LC cell 1910. Similarly, the sealant-filled gap 1904 acts as a buffer between the edge seal 1960 and the mount 1912. The difference in the coefficients of thermal expansion between the substrates 1920 and 1930 relative to the LC unit 1910 is primarily compensated by a combination of the liquid adhesive 1940, the film-based adhesive 1950, and the sealant in the gap 1902. Each of these three components can help allow lateral movement of the LC unit 1910 while also ensuring that the LC unit 1910 remains firmly attached to the substrates 1920 and 1930. Furthermore, the sealant in the gap 1904 provides additional cushioning in the event of movement of the edge seal 1960 relative to the mount 1912, for example, due to the LC unit 1910 pushing or pulling the sealant in the gap 1902. In some embodiments, the gap 1404 may extend to cover the mounting surface of the outer substrate 1920, thereby cushioning the outer substrate 1920 in addition to the edge seal 1960 and the inner substrate 1930.

[0162] As mentioned above Figure 7A Some embodiments may include UV blocking layers and / or IR blocking layers for reducing glare and preventing overheating. For example, a UV / IR blocking layer may be placed between the LC cell and the outer substrate to reduce heating of the internal environment. Similarly, a UV / IR blocking layer may be placed between the LC cell and the inner substrate to reduce heat transfer from the internal environment to the external environment. Such blocking layers are particularly beneficial in built environments where long-term climate control and seasonal temperature variations are required. Blocking UV and IR radiation can also prevent damage to the liquid crystal, such as fading of dopants or dye particles in GH-based liquid crystals. Figures 9A to 9CExamples of this study feature UV blocking in the TAC section of a polarizer. However, UV or IR blocking layers can be incorporated into other layers or treated as separate layers. For example, an LC assembly can have a first IR blocking layer applied (e.g., sputtered) to the inner surface of an outer substrate and a second IR blocking layer applied to the inner surface of an inner substrate. In configurations where applying blocking layers to the inner or outer substrates may be difficult (e.g., when the substrate is three-dimensionally curved glass), or when the LC assembly is formed separately from the outer substrate (e.g., in the case of attachment to a window), blocking layers can be applied to the surface of the LC panel. For example, blocking layers can be applied to... Figure 20 The surface of the flexible membrane 2016 is shown. In some embodiments, UV or IR blocking can be provided by an adhesive with blocking properties or by including blocking particles (e.g., UV blocking particles) within the flexible membrane 2016.

[0163] Figure 20 An LC assembly 2000 suitable for attachment to glass 2020 is shown. The LC assembly 2000 can correspond to... Figure 5A The LC component 510 is used in this case, where the glass 2020 corresponds to the window 520. The LC component 2000 may include, from top to bottom: a first flexible film 9004, a first SiO2 layer 2006, a first ITO layer 2008, an LC layer 2010, a second ITO layer 2012, a second SiO2 layer 2014, and a second flexible film 2016. The LC component 2000 is attached to the glass 2020 via an adhesive 2018.

[0164] Adhesive 2018 may be applied to the flexible film 2016 during manufacturing or during installation (flexible film 2016 and / or glass 2020). Adhesive 2018 may be a liquid adhesive or a film-based adhesive. Adhesive 2018 may be a UV or IR blocking adhesive. Alternatively, a UV and / or IR blocking layer may be applied between the LC layer 2010 and the glass 2020. For example, adhesive 2018 may be a film-based adhesive comprising a first adhesive layer attached to the flexible film 2016, a second adhesive layer for attachment to the glass 2020, and a UV and IR blocking film sandwiched between the first and second adhesive layers. As another example, the flexible film 2016 may include a UV blocking component.

[0165] Flexible films 2004 and 2016 can be formed from PET or similar flexible transparent materials. Flexible films 2004 and 2016 enable the LC assembly 2000 to bend and conform to the attachment surface of the glass 2020. The adhesive 2018 can also be flexible and, for example, can correspond to... Figure 15The liquid adhesive 1540 or the membrane-based adhesive 1550 are used. The flexible membrane 2004 protects the LC assembly 2000 from impact and abrasion. In some embodiments, the flexible membrane 2004 may include a self-healing material (e.g., a self-healing polymer or elastomer) that may be incorporated into the material of the flexible membrane 2004 or as an additional coating.

[0166] SiO2 layers 2006 and 2014 serve as moisture-proof layers to prevent moisture from penetrating into the interior of the LC assembly 2000. Together with edge seals (not shown), SiO2 layers 2006 and 2014 prevent moisture in all directions.

[0167] In the normally black configuration, the LC layer 2010 may include GH liquid crystal, which comprises a mixture of nematic liquid crystal particles and dye particles, as described above. Figure 7C The GH liquid crystal may further include a chiral dopant that twists the liquid crystal particles into a helical structure in a manner similar to that of the TN liquid crystal. However, the LC layer 2010 can be formed of other types of liquid crystal materials. While not strictly necessary, the chiral dopant creates a helical structure that allows the LC layer 2010 to absorb light from all polarization angles, since natural light is 360° polarized. In some embodiments, the proportion of chiral dopant in the GH liquid crystal is at least 0.5% by weight. Without an applied electric field on the ITO layers 2008 and 2012, the long axes of the liquid crystal and dye particles can be aligned perpendicular to the incident light. Applying an electric field to the ITO layers causes the liquid crystal and dye particles to align parallel to the incident light, thereby allowing light to transmit through the LC component 2000. This GH-based normally black configuration can be achieved without a rubbing pattern.

[0168] Figure 21An LC assembly 2100 suitable for attachment to glass 2020 is shown, which, as described above, can correspond to window 520. The LC assembly 2100 is similar to the LC assembly 2000, except that ITO layers 2008 and 2012 are separated from the LC layer 2010 by polyamide (PI) layers 2120 and 2122, respectively. Similar to the LC assembly 2000, the liquid crystal in the LC layer 2010 can be a GH liquid crystal, comprising nematic liquid crystal particles, dye particles, and chiral dopants. To produce a normally white configuration, a rubbing pattern 2105 can be formed on each PI layer facing the LC layer 2010. The rubbing pattern 2105 is formed by rubbing the PI along a predetermined direction, causing the liquid crystal and dye particles to align vertically, thus setting the initial orientation of the liquid crystal and the initial orientation of the dye particles in the LC layer 2010 at the top and bottom of the spiral structure. Therefore, the liquid crystal and dye particles are aligned according to the rubbing direction. Without an applied electric field, the liquid crystal and dye particles located near the rubbing surface are substantially vertically aligned to allow light to pass through. The amount of twist in the helical structure is determined by the chiral dopant. Applying an electric field to the ITO layer causes the helical structure to twist in a manner similar to... Figure 7B The method described in the text regarding TN liquid crystals is undistorted. In the undistorted state, the liquid crystal and dye particles in the LC layer 2010 are essentially horizontally aligned to block light.

[0169] Depending on the direction of the friction pattern, the LC component 2100 can be configured to be normally black and very white. This is due to the alignment provided by the friction pattern 2105. Figure 21 The LC component 2100 in the dark can have a higher performance than in the dark. Figure 20 The LC assembly in the model 2000 produces less haze. Configuration options, such as..., can be achieved by setting the values ​​of one or more parameters in Beer's Law. Figure 20 and Figure 21 The optical performance of LC components, such as LC modules, can be assessed. For example, the transmittance can be altered by adjusting the cell gap distance. Figure 7A (Note: The text appears to be incomplete and contains errors. A more accurate translation would require the full context.) Therefore, the first cell gap for the LC module 2100 can provide transmittance from 13% to 63% in both dark and bright states, and the second cell gap for the LC module can provide transmittance from 19% to 68%. Typically, the transmittance of any embodiment incorporating GH liquid crystal is less than 25% (e.g., 1% to 20%) in the dark state and greater than 20% (e.g., 20% to 70%) in the bright state. GH-based embodiments (e.g.,...) Figure 20 and Figure 21 The typical cell gaps in the embodiments range from 2.5 micrometers to 30 micrometers, and in some cases from 4.5 micrometers to 20 micrometers.

[0170] Example

[0171] Regarding the above embodiments and in conjunction with the accompanying drawings ( Figures 1 to 21 The features described can be combined in various ways. The following are specific examples of aspects incorporated into the previously described embodiments. Additional combinations of features and further modifications will be apparent to those skilled in the art based on this disclosure.

[0172] Example 1

[0173] In some aspects, a liquid crystal (LC) film assembly includes a liquid crystal layer, a first substrate and a second substrate located on opposite sides of the liquid crystal layer, and a first outer layer. The liquid crystal layer includes TN liquid crystal. For example, in Figure 9A In this embodiment, liquid crystal 940 may include liquid crystal with a twist angle in a default (voltage off) state. The first substrate has a first conductive layer, such as an ITO layer 916. Similarly, the second substrate has a second conductive layer, such as an ITO layer 920. Each of the first and second substrates includes a flexible film. For example, as... Figure 9A As shown, layers 914 and 922 correspond to the PC layer. The first outer layer comprises a rigid, transparent material. For example, the first outer layer may correspond to glass layer 902.

[0174] Optionally, the TN liquid crystal has a twist angle of less than or greater than 90 degrees. As mentioned above, the TN liquid crystal is not limited to a twist angle of 90 degrees, and may include, for example, STN, MTN, and liquid crystals with chiral dopants.

[0175] Optionally, the first outer layer has a three-dimensional curvature. For example, glass layer 902 can be bent to match the shape of a vehicle window. Therefore, the first outer layer can be a vehicle window, such as the window of a car, airplane, or ship.

[0176] Optionally, the first outer layer can be a building window, such as a glass door or building window.

[0177] Optionally, the LC film assembly may include a second outer layer comprising a rigid transparent material, wherein the second outer layer has a three-dimensional curvature (e.g., a curvature matching that of the first outer layer), and the first substrate, the second substrate, and the liquid crystal layer are located between the first and second outer layers. For example, the second outer layer may correspond to glass layer 930.

[0178] The flexible film of an LC film assembly can be formed from various flexible materials. For example, the flexible film of the first or second substrate may include PC, PET, or TAC.

[0179] Optionally, the LC film assembly may include an infrared blocking layer located between the first substrate and the first outer layer, wherein the infrared blocking layer comprises polyethylene terephthalate (PET) or another material used as an infrared filter. For example, the infrared blocking layer may correspond to PET layer 906.

[0180] Optionally, the first substrate and the first outer layer can be bonded together with an adhesive. For example, as shown in the image. Figures 9A to 9C As shown and Figure 10 The lamination process shown allows the glass layer to be bonded to the surface of the LC cell with or without an intermediate layer, and PVB is used as an adhesive.

[0181] Optionally, the first substrate and the first outer layer are laminated together through one or more intermediate layers between the first substrate and the outer layer. For example, in Figure 9A In the middle, the glass layer 902 and the PC layer 914 are separated by the PET layer 906 and the polarizer 910.

[0182] Optionally, the LC film assembly may include a control unit (e.g., control unit 530 or 600) configured to generate one or more control signals that establish a voltage between the first and second conductive layers, wherein the magnitude of the voltage determines the arrangement of the TN liquid crystal in the liquid crystal layers. Furthermore, the first outer layer may be a window (e.g., window 520), and the control unit may be attached to the window, such as... Figure 5A and Figure 5B As shown. Furthermore, as... Figure 5A and Figure 5B As shown, the LC film module may include a cutout (e.g., cutout 512) shaped to accommodate a control unit, allowing the control unit to be attached to the window without the intervention of the LC film module. Furthermore, the LC film module may include an optional battery (e.g., battery 620) configured to power the control unit, and an optional photovoltaic cell (e.g., photovoltaic cell 610) configured to recharge the battery using light from a light source illuminating the LC film module, wherein the battery and photovoltaic cell are housed within the control unit.

[0183] Optionally, the first conductive layer and the second conductive layer can be etched to form a pattern on the surface of the first conductive layer and the surface of the second conductive layer. (As described above) Figure 7B The pattern can correspond to multiple regions, each of which can be individually dimmed to display graphics or text. For example, each of the multiple regions can include a first electrode corresponding to a first conductive layer and a second electrode corresponding to a second conductive layer, wherein the region can be individually dimmed by establishing a voltage between the first and second electrodes.

[0184] Example 2

[0185] In some respects, enhancing windows (e.g., Figure 5AThe method for attaching an LC film assembly to a window (520) includes attaching an LC film assembly to a window, wherein the window is an automotive or architectural (building) window, and wherein the LC film assembly includes a liquid crystal layer, a first substrate and a second substrate located on opposite sides of the liquid crystal layer, and a first outer layer. The liquid crystal layer includes TN liquid crystal. The first substrate has a first conductive layer. Similarly, the second substrate has a second conductive layer. Each of the first and second substrates includes a flexible film. Attaching the LC film assembly to the window may include placing the LC film assembly against the window such that the surface of the first substrate substantially conforms to the surface of the window. For example, in Figure 5B In the case of a sunroof, if window 520 has a three-dimensional curvature (as in the case of a car sunroof), then if LC component 510 includes, for example, Figure 9A The flexible membrane of PC layer 914 allows the LC module 510 to be placed on the window 520 with a curvature that matches that of the window 520. Furthermore, the flexible membrane allows the LC module to conform to surfaces that are substantially, but not perfectly, flat. For example, a building window may appear flat to the naked eye, but there may still be minute height variations of 1 mm or more on its surface.

[0186] As an alternative to TN liquid crystals, the LC film assembly connected to the window can include GH liquid crystals, and can be configured according to, for example... Figure 20 or Figure 21 The example is constructed as follows. Therefore, the LC film assembly may include a GH liquid crystal layer comprising a mixture of a nematic liquid crystal as the host, dye molecules as the guest, and optionally a chiral dopant. The LC film assembly may also include a first substrate having a first conductive layer and a second substrate having a second conductive layer (similar to the first and second substrates in the TN embodiment described earlier in this example). For example, both conductive layers may be formed as ITO coatings. The first and second substrates are located on opposite sides of the GH liquid crystal layer. Each of the first and second substrates includes a flexible film (e.g., flexible films 2004 and 2016). Although Figure 20 and Figure 21 No spacers are shown, but it should be understood that, for example... Figure 7AThe spacers 708 can be incorporated into the LC film assembly to define, for example, cell gaps between 2.5 μm and 30 μm. The amount of chiral dopant in the GH liquid crystal layer can be at least 0.5% of the weight of the GH liquid crystal layer. Similar to the TN-based example described above, the GH liquid crystal can be configured to switch the LC film assembly between a darkened state (minimum transmittance) and a brightened state (maximum transmittance) in response to a voltage applied across the first and second conductive layers. In the darkened state, the LC film assembly can have a total transmittance between 1% and 20% (total transmittance across all layers of the LC film assembly). In the brightened state, the LC film assembly has a total transmittance between 20% and 70%. The LC film assembly can be connected in a similar manner to that described above, by placing the LC film assembly against a window such that the first substrate conforms to the surface of the window.

[0187] Optionally, the flexible film of the first substrate or the flexible film of the second substrate may include PC, PET or TAC.

[0188] Optionally, attaching the LC membrane assembly to the window may further include applying an adhesive to at least one of the surfaces of the first substrate or the window before placing the LC membrane assembly against the window. The adhesive may be a liquid adhesive, such as a transparent, water-based, or solvent-based adhesive, which forms a bond between the LC membrane assembly and the window upon evaporation. Alternatively, the adhesive may be membrane-based. In some embodiments, the membrane-based adhesive may cover at least the window-facing side with a protective film, which is peeled off to expose the membrane-based adhesive. The membrane-based adhesive may be pre-applied to the LC membrane assembly (e.g., applied to the first substrate during manufacturing) or applied to the LC membrane assembly when it is attached to the window.

[0189] Alternatively, connecting the LC film assembly to the window may further include applying pressure to the LC film assembly after it has been placed against the window, such that the pressure removes air bubbles trapped between the first substrate and the window. The pressure may be applied manually, possibly using a tool such as a scraper, to guide the air bubbles to the edge of the LC film assembly.

[0190] Optionally, the method may include connecting a control unit to a window, wherein the control unit is configured to apply a voltage between a first conductive layer and a second conductive layer by generating one or more control signals. The method may further include connecting the control unit to an electrical interface of the LC film assembly, for example, using a cable configured to carry one or more control signals, as described above. Figure 6A The control unit can be attached to any location on the window. For example, the method could include placing the control unit in a corner or the center of the window.

[0191] Typically, the size of the LC film module is approximately the same as the window size, in which case the control unit can be placed along the edge of the LC film module. For example, the control unit can be attached by placing it within a cutout (e.g., cutout 512) provided in the LC film module, wherein the cutout is configured to allow ambient light (e.g., sunlight) to reach the photovoltaic cells of the control unit without penetrating the individual layers of the LC cells (e.g., the first substrate and the second substrate). As described above... Figure 6A The photovoltaic cells can be used to charge the battery of the control unit.

[0192] Example 3

[0193] In some respects, LC film modules suitable for attachment to building windows include a GH liquid crystal layer comprising a nematic liquid crystal as the host, dye molecules as the guest, and optional chiral dopants. Such LC film modules can, for example, be based on... Figure 20 or Figure 21 The LC film assembly is constructed using examples and can be combined with aspects of the additional embodiments described herein. The LC film assembly includes a first substrate having a first conductive layer and a second substrate having a second conductive layer. The first and second substrates are located on opposite sides of a GH liquid crystal layer. Each of the first and second substrates includes a flexible film. The LC film assembly also includes a plurality of spacers located between the first and second substrates. The spacers define and are configured to maintain a cell gap between 2.5 μm and 30 μm. A chiral dopant is at least 0.5% by weight of the GH liquid crystal layer. The GH liquid crystal layer is configured to cause the LC film assembly to switch between a darkening state and a brightening state in response to a voltage applied across the first and second conductive layers. In the darkening state, the total transmittance of the LC film assembly is between 1% and 20%. In the brightening state, the LC film assembly has a total transmittance between 20% and 70%. The LC film assembly is attached to the glass surface of a building window, for example, the first substrate being the outermost layer of the LC film assembly closest to the building window. The LC film assembly can switch directly between the darkening and brightening states, or in a manner such as... Figure 6A The switching is gradual (e.g., in incremental steps) under the instruction of a control unit such as a control unit in the system.

[0194] Optionally, the LC film assembly is typically black, and the GH liquid crystal layer is configured to establish a darkened state when there is no voltage between the first conductive layer and the second conductive layer.

[0195] Optionally, the LC film assembly is typically white, and the GH liquid crystal layer is configured to establish a lit state when there is no voltage between the first conductive layer and the second conductive layer.

[0196] Optionally, the LC membrane module is formed separately from the building window and connected by an adhesive located between the first substrate and the building window. Therefore, the LC membrane module can be attached as an aftermarket product. The adhesive can be a liquid adhesive or a film-based adhesive.

[0197] When the outermost layer facing the building window is the first substrate, the flexible film of the first substrate can be configured to conform to the height variations of the building window glass surface. The LC film assembly as a whole can also conform to the glass surface of the building window.

[0198] Optionally, the flexible film of the first substrate or the flexible film of the second substrate may include PC, PET or TAC.

[0199] Optionally, the LC film assembly may further include a first PI coating between the first conductive layer and the GH liquid crystal layer, and similarly, a second PI coating between the second conductive layer and the GH liquid crystal layer. The first PI coating and the second PI coating may correspond to... Figure 21 The PI layers 2120 and 2122 in the liquid crystal, and therefore each may include a rubbing pattern that determines the initial orientation of the nematic liquid crystal (and therefore also the initial orientation of the dye molecules).

[0200] Optionally, the LC film assembly may further include a control unit configured to change the voltage between the first conductive layer and the second conductive layer according to the level of ambient light. Figure 6A An example of such a control unit is described, wherein the control unit includes a battery and a photovoltaic cell configured to charge the battery using ambient light.

[0201] Optionally, the LC membrane assembly may also include a cutout shaped to accommodate a control unit (e.g., cutout 512). The cutout may be positioned along the edge or corner of the LC membrane assembly (e.g., Figure 5A (as shown), and allows the control unit to be directly attached to the building window.

[0202] Optionally, the LC film assembly may further include one or more of the following additional layers: (1) a blocking layer configured to reduce the amount of ultraviolet light transmitted to the GH liquid crystal layer; (2) a blocking layer configured to reduce the amount of infrared light transmitted to the GH liquid crystal layer; or (3) a moisture barrier configured to prevent moisture from reaching the GH liquid crystal layer. For example, the LC film assembly may include combined UV and IR blocking films, separate UV and infrared blocking films, UV and / or IR blocking particles in a first or second substrate, one or more SiO2 coatings (e.g., SiO2 layers 2006 and 2014), or any combination thereof.

[0203] Optionally, the first and second conductive layers can be divided into multiple regions, which can be individually controlled to adjust the transmittance of each region. For example, regions can be formed by etching a pattern into the first conductive layer and a corresponding pattern into the second conductive layer to define multiple pairs of electrodes. Such regions allow for selective dimming of individual regions, as described above. Figures 3A to 3C and Figure 4 As described.

[0204] Example 4

[0205] In some respects, LC film assemblies suitable for attachment to automotive windows (e.g., sunroofs) include a GH liquid crystal layer comprising a nematic liquid crystal as the host, dye molecules as the guest, and optionally a chiral dopant. Such LC film assemblies can, for example, be based on... Figure 20 or Figure 21 The LC film assembly is constructed using examples and can be combined with aspects of the additional embodiments described herein. The LC film assembly includes a first substrate having a first conductive layer and a second substrate having a second conductive layer. The first and second substrates are located on opposite sides of a GH liquid crystal layer. Each of the first and second substrates includes a flexible film. The LC film assembly also includes a plurality of spacers located between the first and second substrates. The spacers define and are configured to maintain a cell gap between 2.5 μm and 30 μm. A chiral dopant is at least 0.5% by weight of the GH liquid crystal layer. The GH liquid crystal layer is configured to cause the LC film assembly to switch between a darkening state and a brightening state in response to a voltage applied across the first and second conductive layers. In the darkening state, the total transmittance of the LC film assembly is between 1% and 20%. In the brightening state, the LC film assembly has a total transmittance between 20% and 70%. The LC film assembly is attached to a three-dimensional curved surface of an automotive window; for example, the first substrate is the outermost layer of the LC film assembly closest to the automotive window. The LC film assembly can switch directly between the darkening and brightening states, or in a manner such as... Figure 6A The switching is gradual (e.g., in incremental steps) under the instruction of a control unit such as a control unit in the system.

[0206] Optionally, the LC film assembly is typically black, and the GH liquid crystal layer is configured to establish a darkened state when there is no voltage between the first conductive layer and the second conductive layer.

[0207] Optionally, the LC film assembly is typically white, and the GH liquid crystal layer is configured to establish a lit state when there is no voltage between the first conductive layer and the second conductive layer.

[0208] Optionally, the LC film assembly is formed separately from the automotive window and bonded to it via an adhesive located between the first substrate and the automotive window. Therefore, the LC film assembly can be attached as an aftermarket product. The adhesive can be a liquid adhesive or a film-based adhesive.

[0209] When the outermost layer facing the car window is the first substrate, the flexible film of the first substrate can be configured to conform to the curvature of a three-dimensional curved surface. The LC film assembly as a whole can also conform to the curvature of a three-dimensional curved surface.

[0210] Optionally, the flexible film of the first substrate or the flexible film of the second substrate may include PC, PET or TAC.

[0211] Optionally, the LC film assembly may further include a first PI coating between the first conductive layer and the GH liquid crystal layer, and similarly, a second PI coating between the second conductive layer and the GH liquid crystal layer. The first PI coating and the second PI coating may correspond to... Figure 21 The PI layers 2120 and 2122 in the liquid crystal, and therefore each may include a rubbing pattern that determines the initial orientation of the nematic liquid crystal (and therefore also the initial orientation of the dye molecules).

[0212] Optionally, the LC film assembly may further include a control unit configured to change the voltage between the first conductive layer and the second conductive layer according to the level of ambient light. Figure 6A An example of such a control unit is described, wherein the control unit includes a battery and a photovoltaic cell configured to charge the battery using ambient light.

[0213] Optionally, the LC membrane assembly may also include a cutout shaped to accommodate a control unit (e.g., cutout 512). The cutout may be positioned along the edge or corner of the LC membrane assembly (e.g., Figure 5A (as shown), and allows the control unit to be directly attached to the car window.

[0214] Optionally, the LC film assembly may further include one or more of the following additional layers: (1) a blocking layer configured to reduce the amount of ultraviolet light transmitted to the GH liquid crystal layer; (2) a blocking layer configured to reduce the amount of infrared light transmitted to the GH liquid crystal layer; or (3) a moisture barrier configured to prevent moisture from reaching the GH liquid crystal layer. For example, the LC film assembly may include combined UV and IR blocking films, separate UV and infrared blocking films, UV and / or IR blocking particles in a first or second substrate, one or more SiO2 coatings (e.g., SiO2 layers 2006 and 2014), or any combination thereof.

[0215] Optionally, the first and second conductive layers can be divided into multiple regions, which can be individually controlled to adjust the transmittance of each region. For example, regions can be formed by etching a pattern into the first conductive layer and a corresponding pattern into the second conductive layer to define multiple pairs of electrodes. Such regions allow for selective dimming of individual regions, as described above. Figures 3A to 3C and Figure 4 As described.

[0216] Example 5

[0217] In some aspects, a method for laminating an LC assembly includes sequentially forming a stack comprising: a first rigid outer layer, a PVB layer, a first substrate having a first conductive layer, a liquid crystal layer, a second substrate having a second conductive layer, and a second rigid outer layer. For example, this stack may correspond to... Figure 10 The method also includes, after forming the stack, heating the PVB layer until the PVB layer is at least partially melted, and then cooling the PVB layer until the PVB is re-cured.

[0218] Optionally, the liquid crystal layer includes twisted nematic liquid crystal, guest-host liquid crystal, or vertically aligned liquid crystal.

[0219] Optionally, at least one of the first substrate, the second substrate, or the outer layer comprises polycarbonate.

[0220] Optionally, the stack further includes a polarizer, which comprises a polarizing plate, a TAC coating, and a UV blocking coating. As described above, Figure 10 The LC component 1000 in the text is a simplified representation of an LC component. Therefore, the laminated layers can correspond to one of the previously described LC components, such as... Figure 9A The LC component 900. Furthermore, the method may include forming liquid crystal cells to contain liquid crystal in a liquid crystal layer, wherein forming the liquid crystal cells includes applying a sealant between a first substrate and a second substrate using a non-UV-curable adhesive, and the sealant respectively defining the boundaries of the liquid crystal cells. For example, as described above, Figure 11 Adhesive 1102 in the formula is a UV adhesive, but it can be replaced by two-part epoxy resin or other non-UV curing adhesives.

[0221] In addition to applying a sealant between the first substrate and the second substrate, the method may also include placing a spacer between the first substrate and the second substrate, wherein the spacer is rectangular or cylindrical and defines a cell gap between the first substrate and the second substrate.

[0222] When a sealant is applied between the first substrate and the second substrate, the first conductive layer or the second conductive layer may include ITO. For example, the first conductive layer and the second conductive layer may correspond to ITO layers 916 and 920, respectively. Therefore, in some cases, the sealant may be applied to the surface of the ITO layer.

[0223] Optionally, the heating of the PVB layers can be performed at a temperature between 100°C and 160°C, and pressure can be applied to the stack via a mechanical or vacuum environment. For example, the temperature can be set between 110°C and 120°C to heat the PVB layers. The pressure applied to the stack can be generated using a vacuum chamber or vacuum bag, in which case the method may include setting the pressure between 1 bar and 4 bar. Alternatively, the pressure can be a mechanically applied pressure of 10 bar to 15 bar.

[0224] Example 6

[0225] In some aspects, the LC assembly includes a stack that, in sequence, comprises: a first rigid outer layer, a PVB layer, a first substrate including a first flexible film and having a first conductive layer, a liquid crystal layer including nematic liquid crystal and a chiral dopant, a second substrate including a second flexible film and having a second conductive layer, and a second rigid outer layer. The stack is a laminated stack formed as a result of heating the PVB layer until it is at least partially melted, and then cooling the PVB layer until it is re-solidified, for example, according to the above regarding... Figure 10 The described process.

[0226] Optionally, the liquid crystal layer includes guest-host liquid crystal.

[0227] Optionally, at least one of the first rigid outer layer or the second rigid outer layer comprises polycarbonate.

[0228] Optionally, the stack further includes a polarizer comprising a polarizing plate, a TAC coating, and a UV blocking coating. Furthermore, the LC assembly may also include liquid crystal cells containing nematic liquid crystals in a liquid crystal layer, wherein the liquid crystal cells include a sealant applied between a first substrate and a second substrate using a non-UV-curable adhesive, and the sealant respectively defines the boundary of the liquid crystal cell. Additionally, the LC assembly may include a spacer located between the first substrate and the second substrate, wherein the spacer is rectangular or cylindrical and defines a cell gap between the first substrate and the second substrate. Optionally, the first conductive layer or the second conductive layer may include ITO and be located between the polarizer and the liquid crystal layer.

[0229] Example 7

[0230] In some aspects, the LC assembly includes a first substrate and a second substrate. The first and second substrates may be rigid or flexible substrates. In some embodiments, the first and second substrates comprise glass. The LC assembly also includes an LC panel located between the first and second substrates. The LC assembly further includes an edge seal extending at least partially around the periphery of the LC assembly. Like the LC panel, the edge seal is located between the first and second substrates. The overall thickness of the LC assembly, including the first substrate, the second substrate, and the LC panel, can be configured to allow the LC assembly to operate as an automotive window (e.g., a sunroof or side window).

[0231] An LC panel is a multilayer stack, including an LC layer located between a first conductive layer and a second conductive layer. The LC panel also includes one or more additional layers between the first conductive layer and a first substrate and / or between the second conductive layer and the second substrate. The one or more additional layers include a material different from the material of the first and second substrates (e.g., PVB). Therefore, the LC panel has a different coefficient of thermal expansion than the first and second substrates.

[0232] The LC panel is bonded to a first substrate and a second substrate using a combination of liquid adhesive and film-based adhesive, for example, as described above. Figure 14 The liquid adhesive and film-based adhesive are configured to maintain a flexible bond over a temperature range of at least -40°C to +115°C. Optionally, an adhesive with a higher bond strength than the liquid adhesive and film-based adhesive can be used to bond the edge seal to the first and second substrates. In some embodiments, the liquid adhesive and film-based adhesive comprise acrylic acid, and the adhesive for the edge seal comprises a resin.

[0233] Optionally, the coefficient of friction of the edge seal is less than or equal to the coefficient of friction of the first substrate and the second substrate. For example, if the first substrate and the second substrate are glass, the edge seal may be PET.

[0234] Optionally, the thickness of the second substrate is less than the thickness of the first substrate. For example, as described above... Figure 16 The outer substrate (e.g., the first substrate) discussed can range from approximately 2 mm to 3.5 mm in thickness, and the inner substrate (e.g., the second substrate) can range from approximately 0.7 mm to 2 mm in thickness. The total thickness of the entire LC assembly is approximately 5 mm or less.

[0235] Optionally, the first substrate extends through the edge seal and the second substrate, and provides a mounting surface for connecting the LC assembly to the mount, for example, as... Figure 16 As shown. The LC assembly may further include a filler block flush with the first substrate (e.g., Figure 17(filler 1705). Alternatively, the first substrate, the second substrate, and the edge seal are common-terminated to define a flush mounting surface, such as... Figure 18 As shown.

[0236] Optionally, the edge seal is separated from the LC panel through a first gap filled with a flexible sealant. The first gap may be completely filled with a liquid adhesive, or as... Figure 19 As shown, areas not occupied by the liquid adhesive are filled with a different material (e.g., another adhesive). In addition to the first gap, the edge seal can optionally be separated from the mount via a second gap when the LC assembly is in an attached configuration relative to the mount. Like the first gap, the second gap is filled with a flexible sealant. The sealant in the second gap can be applied to the edge seal during the manufacture of the LC assembly or during the attachment of the LC assembly to the mount. The sealant in the first gap and / or the second gap can be a non-adhesive sealant.

[0237] The foregoing description of embodiments of this disclosure is for illustrative purposes only and is not intended to be exhaustive or to limit this disclosure to its precise forms. Those skilled in the art will understand that many modifications and variations are possible based on the above disclosure.

[0238] Some portions of this specification describe embodiments of the present disclosure based on algorithms and symbolic representations of information operations. Those skilled in the art of data processing typically use these algorithmic descriptions and representations to effectively communicate the substance of their work to others skilled in the art. While these operations are described functionally, computationally, or logically, they should be understood as being implemented through computer programs or equivalent circuits, microcode, etc. Furthermore, it has sometimes proven convenient to refer to these operations as modules without loss of generality. The described operations and their associated modules can be embodied in software, firmware, and / or hardware.

[0239] The described steps, operations, or processes may be performed or implemented using one or more hardware or software modules, alone or in combination with other devices. In some embodiments, the software modules are implemented using a computer program product, which includes a computer-readable medium containing computer program code that can be executed by a computer processor for performing any or all of the described steps, operations, or processes.

[0240] Embodiments of this disclosure may also relate to means for performing the operations. Such means may be specifically configured for the desired purpose, and / or may comprise a general-purpose computing device selectively activated or reconfigured by a computer program stored in a computer. Such a computer program may be stored in a non-transitory, tangible, computer-readable storage medium, or in any type of medium suitable for storing electronic instructions, which may be coupled to a computer system bus. Furthermore, any computing system mentioned in the specification may include a single processor, or may be an architecture employing a multi-processor design to enhance computing power.

[0241] Embodiments of this disclosure may also relate to products produced through the computational processes described herein. Such products may include information generated by the computational processes, wherein the information is stored on a non-transitory, tangible, computer-readable storage medium, and may include any embodiment of a computer program product or other combinations of data described herein.

[0242] The language used in this specification has been chosen primarily for readability and pedagogical purposes and may not be intended to depict or limit the subject matter of the invention. Therefore, the scope of this disclosure is not limited by this detailed description, but rather by any of the claims based on the application made herein. Thus, the disclosure of embodiments is intended to illustrate, but not limit, the scope of the disclosure set forth in the following claims.

[0243] Following the description of several embodiments, various modifications, alternative structures, and equivalents may be used without departing from the spirit of this disclosure. For example, the aforementioned elements may simply be components of a larger system, where other rules may take precedence over or otherwise modify the application of the various embodiments. Furthermore, multiple steps may be performed before, during, or after considering the aforementioned elements. Therefore, the above description does not limit the scope of this disclosure.

Claims

1. A liquid crystal film assembly, comprising: The host-guest (GH) liquid crystal layer includes nematic liquid crystal, dye molecules, and chiral dopants; A first substrate having a first conductive layer and a second substrate having a second conductive layer, the first substrate and the second substrate being located on opposite sides of the host-guest (GH) liquid crystal layer, wherein each of the first substrate and the second substrate includes a flexible film; and A plurality of spacers are provided between the first substrate and the second substrate, the plurality of spacers defining a unit gap between 2.5 μm and 30 μm, wherein: The chiral dopant is at least 0.5% of the weight of the host-guest (GH) liquid crystal layer. The host-guest (GH) liquid crystal layer is configured to cause the liquid crystal film assembly to switch between a darkening state and a brightening state in response to a voltage applied across the first conductive layer and the second conductive layer. In the darkened state, the total transmittance of the liquid crystal film module is between 1% and 20%. In the brightened state, the total transmittance of the liquid crystal film module is between 20% and 70%, and The liquid crystal film assembly is attached to the glass surface of the building window. The liquid crystal film assembly further includes: A control unit configured to change the voltage across the first conductive layer and the second conductive layer according to the intensity of ambient light; A cutout, shaped to accommodate the control unit, wherein the cutout is positioned along the edge or corner of the liquid crystal film assembly and allows the control unit to be directly attached to the building window.

2. The liquid crystal film assembly according to claim 1, wherein the host-guest (GH) liquid crystal layer is configured to establish a darkening state when there is no voltage between the first conductive layer and the second conductive layer.

3. The liquid crystal film assembly according to claim 1, wherein the host-guest (GH) liquid crystal layer is configured to establish a brightening state when there is no voltage between the first conductive layer and the second conductive layer.

4. The liquid crystal film assembly according to claim 1, wherein the liquid crystal film assembly is formed separately from the building window and is connected by an adhesive located between the first substrate and the building window.

5. The liquid crystal film assembly according to claim 4, wherein the adhesive is a liquid adhesive.

6. The liquid crystal film assembly of claim 4, wherein the adhesive is a film-based adhesive.

7. The liquid crystal film assembly of claim 1, wherein the flexible film of the first substrate is configured to adapt to height variations along the glass surface of the building window.

8. The liquid crystal film assembly according to claim 1, wherein the flexible film of the first substrate or the flexible film of the second substrate comprises polycarbonate (PC), polyethylene terephthalate (PET), or cellulose triacetate (TAC).

9. The liquid crystal film assembly according to claim 1, further comprising: A first polyamide (PI) coating between the first conductive layer and the host-guest (GH) liquid crystal layer; and A second polyamide (PI) coating between the second conductive layer and the host-guest (GH) liquid crystal layer, wherein the first polyamide (PI) coating and the second polyamide (PI) coating each include a rubbing pattern that defines the initial orientation of the nematic liquid crystal.

10. The liquid crystal film assembly of claim 1, wherein the control unit includes a battery and a photovoltaic cell, the photovoltaic cell being configured to charge the battery using the ambient light.

11. The liquid crystal film assembly of claim 1, further comprising one or more of the following additional layers: A barrier layer is configured to reduce the amount of ultraviolet light transmitted to the host-guest (GH) liquid crystal layer; A barrier layer is configured to reduce the amount of infrared light transmitted to the host-guest (GH) liquid crystal layer; or A moisture barrier configured to prevent moisture from reaching the host-guest (GH) liquid crystal layer.

12. The liquid crystal film assembly according to claim 1, wherein the first conductive layer and the second conductive layer are divided into multiple regions, and the multiple regions can be individually controlled to adjust the transmittance of each region.

13. A liquid crystal film assembly, comprising: The host-guest (GH) liquid crystal layer includes nematic liquid crystal, dye molecules, and chiral dopants; A first substrate having a first conductive layer and a second substrate having a second conductive layer, the first substrate and the second substrate being located on opposite sides of the host-guest (GH) liquid crystal layer, wherein each of the first substrate and the second substrate includes a flexible film; a plurality of spacers located between the first substrate and the second substrate, the plurality of spacers defining a cell gap between 2.5 μm and 30 μm; a control unit configured to change the voltage across the first conductive layer and the second conductive layer according to the intensity of ambient light; a notch shaped to accommodate the control unit, wherein the notch is positioned along an edge or corner of the liquid crystal film assembly and allows the control unit to be directly attached to a vehicle window, wherein: The chiral dopant is at least 0.5% of the weight of the host-guest (GH) liquid crystal layer, which is configured to switch between a darkened state and a brightened state in response to a voltage applied across the first and second conductive layers in a darkened state. The liquid crystal assembly has a total transmittance between 1% and 20% in a brightened state, and the liquid crystal assembly has a total transmittance between 20% and 70% in a brightened state. The liquid crystal assembly is attached to the three-dimensional curved surface of the automotive window.

14. The liquid crystal film assembly according to claim 13, wherein, The car window in question is a sunroof.

15. The liquid crystal film assembly according to claim 13, wherein, The liquid crystal film assembly is formed separately from the vehicle window and is attached via an adhesive located between the first substrate and the vehicle window.

16. The liquid crystal film assembly of claim 15, wherein the adhesive is a liquid adhesive or a film-based adhesive.

17. The liquid crystal film assembly according to claim 13, wherein, The flexible film of the first substrate is configured to conform to the curvature of the three-dimensional curved surface.

18. The liquid crystal film assembly according to claim 13, wherein the flexible film of the first substrate or the flexible film of the second substrate comprises polycarbonate (PC), polyethylene terephthalate (PET), or cellulose triacetate (TAC).

19. The liquid crystal film assembly of claim 13, wherein the first conductive layer and the second conductive layer are divided into a plurality of regions, the plurality of regions being individually controllable to adjust the transmittance of each region.

20. A method for enhancing a window, the method comprising: An adhesive is used to attach the liquid crystal film assembly to the surface of the window, wherein the liquid crystal film assembly comprises: The host-guest (GH) liquid crystal layer includes nematic liquid crystal, dye molecules, and chiral dopants; A first substrate having a first conductive layer and a second substrate having a second conductive layer, the first substrate and the second substrate being located on opposite sides of the host-guest (GH) liquid crystal layer, wherein each of the first substrate and the second substrate includes a flexible film; a plurality of spacers located between the first substrate and the second substrate, the plurality of spacers defining a cell gap between 2.5 μm and 30 μm; a control unit configured to change the voltage across the first conductive layer and the second conductive layer according to the intensity of ambient light; a notch shaped to accommodate the control unit, wherein the notch is positioned along an edge or corner of the liquid crystal film assembly and allows the control unit to be directly attached to the window, wherein: The chiral dopant is at least 0.5% of the weight of the host-guest (GH) liquid crystal layer, which is configured to switch between a darkened state and a brightened state in response to a voltage applied across the first and second conductive layers in a darkened state. The liquid crystal assembly has a total transmittance between 1% and 20% in a brightened state, and the liquid crystal assembly has a total transmittance between 20% and 70% in a brightened state. Attaching the liquid crystal assembly to the window includes placing the liquid crystal assembly against the window such that the first substrate conforms to the surface of the window.

21. The method according to claim 20, wherein, The surface of the window has a three-dimensional curvature.

22. The method according to claim 20, wherein, The flexible film of the first substrate or the flexible film of the second substrate includes polycarbonate (PC), polyethylene terephthalate (PET), or cellulose triacetate (TAC).

23. The method of claim 20, wherein, The adhesive is a liquid adhesive, and attaching the liquid crystal film assembly to the window further includes applying the liquid adhesive to at least one of the surfaces of the first substrate or the window before placing the liquid crystal film assembly against the window.

24. The method according to claim 23, wherein, The liquid adhesive is a transparent, water-based or solvent-based adhesive that forms a bond between the liquid crystal film assembly and the window upon evaporation.

25. The method according to claim 20, wherein, The adhesive is a film-based adhesive covered by a protective film, and attaching the liquid crystal film assembly to the window further includes peeling off the protective film to expose the film-based adhesive before placing the liquid crystal film assembly against the window.

26. The method of claim 20, further comprising: After the liquid crystal film assembly is placed against the window, pressure is applied to the liquid crystal film assembly, wherein the pressure removes air bubbles trapped between the first substrate and the window.

27. The method of claim 20, further comprising: A control unit is attached to the window, wherein the control unit is configured to apply the voltage between the first conductive layer and the second conductive layer; as well as The control unit is connected to the electrical interface of the liquid crystal film assembly, wherein the electrical interface is configured to transmit electrical signals from the control unit to establish the voltage.

28. The method according to claim 27, wherein, The control unit includes a battery and a photovoltaic cell, the photovoltaic cell being configured to charge the battery using ambient light, and wherein attaching the control unit to the window includes placing the control unit within a cutout provided in the liquid crystal film assembly, the cutout being configured to allow the ambient light to reach the photovoltaic cell without passing through the first substrate and the second substrate.

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