Method for producing a flexible electro-optical component

Abstract

The present invention discloses a method for producing a flexible element unit for an optical device, the flexible element unit being surrounded by a boundary seal and filled with an electro-optical material, the flexible element unit having a first substrate and a second substrate separated by a controlled distance, the method comprising: providing two continuous sheets of flexible plastic material to form the first substrate and the second substrate, depositing a boundary sealant on at least one of the first substrate and the second substrate to define the boundary seal, depositing an electro-optical material on at least one substrate, the electro-optical material being in a non-discrete, non-encapsulated, non-polymer state and containing less than 1% of a polymerizable material, wherein the electro-optical material is generally non-polymerizable; and matching the first substrate and the second substrate when roll-filling the flexible element with the electro-optical material using one or more laminating rollers so that the electro-optical material completely fills the controlled distance between the first substrate and the second substrate.

Description

[0001] This application was filed on November 3, 2015, and the invention name is "For producing flexible

[0002] A divisional application of the invention patent application with application number 201580062129.8. Background Art

[0003] Most liquid crystal (LC) devices are made of a liquid crystal sandwich between two separated glass substrates coated with a transparent conductor. These glass substrates are usually held together at the edges using an epoxy-based gasket (edge ​​seal) to a predetermined gap and are called a panel. Liquid crystal is injected into the gap of the panel using a vacuum filling process or a one drop filling process. In the case of a vacuum filling process, the gasket surrounding the panel is discontinuous and has an opening called a "filling hole". The panel is then placed in a vacuum chamber to evacuate air from within the panel. After this step, and while still under vacuum, liquid crystal is introduced into the filling hole. Due to capillary forces, the liquid crystal then fills the gap within the panel. This can be accelerated by bringing the panel to atmospheric pressure after the liquid crystal is introduced into the filling hole. Once the liquid crystal has filled the panel gap, the process is complete. However, in order to avoid future problems (e.g., shrinkage, formation of bubbles, etc.), the amount of liquid crystal in the panel is more than the expected volume. Therefore, the panels are then squeezed through a process called "cold pressing" to remove excess liquid crystal. A secondary epoxy is then used to seal the fill hole to prevent air from entering the panel.

[0004] This process is difficult to perform in large area panels because the filling time is proportional to the panel area, so the waiting time required to complete the filling process may take several hours for each panel. This process is not economical, especially for the additional time required to exhaust the air during the vacuum process. In addition, the control of the component gap becomes excessively difficult.

[0005] The use of flexible substrates in traditional vacuum processing presents another difficulty. When the air in the vacuum chamber is evacuated, any trapped air in the empty element causes the empty element to expand, like a balloon. This can lead to damage to the element or rupture of the element's gasket. For the vacuum filling process, additional precautions are required, such as sandwiching the flexible element between two ridged materials to prevent bulging.

[0006] To alleviate this problem, a new method called single drop filling (ODF) was invented. In this method, the glass substrate is coated. The gasket is deposited around the entire circumference of the glass substrate. The substrate is then placed in a large vacuum chamber. A second glass substrate is also placed in the vacuum chamber and is held above the original substrate. At this point, a dispenser deposits the exact amount of liquid crystal required on the bottom glass substrate. Once a vacuum state is achieved, the two substrates are brought together. The epoxy gasket is cured, thereby forming a sealed system. The liquid crystal fills the panel through capillary forces. The panel can be brought to atmospheric pressure to accelerate the filling process as previously described. The advantage of the ODF method is that the cold pressing step is omitted. In addition, the system can reduce processing time, especially for large area panels.

[0007] An important aspect of these processing methods is that the final panel is considered to be under negative pressure. In other words, because the panel is manufactured under vacuum, the internal pressure is considered to be lower than atmospheric pressure. This means that air will penetrate the panel if given the opportunity. Therefore a breach in the gasket will result in catastrophic failure of the panel. To avoid this problem, the gaskets are designed to be air impermeable.

[0008] Glass-based panels cannot be used in applications where durability, flexibility or lightness are important. Such applications include goggles, protective screens, highly curved windows / displays, etc. Therefore, there is a need for flexible plastic LC devices.

[0009] The manufacturing methods used for the production of liquid crystal panels are not completely compatible with plastic substrates. On the one hand, plastics are flexible, making the handling of plastic substrates particularly difficult during the production process. The lack of glass flexibility, which is considered to be an obstacle to many applications, is in fact necessary for the production process stated above. Although some small-area plastic components have been manufactured using the above conventional processes, low yields have limited their introduction. This is mainly due to the strict conditions required for any vacuum filling process. In addition, once the panel is made, these plastic-based devices have a significantly lower service life. This is due to the fact that plastics are permeable materials that allow gas transmission. Because these panels are made under negative pressure, air will eventually enter the component. This significantly limits the introduction of plastic-based liquid crystal devices. Although many companies (e.g., Teijin, DuPont, Mitsubishi, etc.) have been committed to studying hard coatings to reduce the permeability of plastic substrates, they have not yet reached the values ​​provided by even the thinnest glass.

[0010] Some plastic-based liquid crystal devices have appeared on the market. They try to overcome these problems by processing the system at atmospheric pressure. One way to achieve this is to eliminate the gasket seal and place the liquid crystal on the substrates using a roller. However, in order to avoid the liquid crystal from coming out of the panel due to the lack of gasket seals, they also introduce a significant amount of polymer. In this method, the liquid crystal material is "encapsulated", meaning that a certain amount of liquid crystal material is enclosed or contained in an encapsulation medium. This micro-encapsulation prevents the liquid crystal from "flowing", thereby making it possible to manufacture large displays. The polymer encapsulating the liquid crystal forms a micro "panel" within the large panel. The polymer also helps maintain the element gap by adhering to the two substrates. These materials, most commonly known as polymer dispersed liquid crystal (PDLC), nematic curve arrangement phase (N-CAP), polymer stable cholesteric structure (PSCT), polymer encapsulated liquid crystal (PELC) and polymer network liquid crystal (PNLC), have significant disadvantages because they do not show optical transparency and become blurred due to the light scattering caused by the encapsulated liquid crystal domain. This has limited their use to privacy applications (e.g., privacy windows). It should be noted that due to the lack of the gasket, these systems lack the stability of these glass panels. Specifically, over time, air and moisture penetrate the panel and render the product inoperable. Therefore, these systems have not yet achieved marketability. In order to overcome this limitation, the package size achieved by the polymer has been increased. In addition, patterned micro panels are formed to limit the flow of the liquid crystal in the final large panel. However, these additional structures reduce the optical performance of the element and cause additional effects such as diffraction. In optical device applications, devices are needed in which these polymer walls and structures are not present in order to avoid any optical artifacts in the viewing area.

[0011] Other proposed solutions include, for example, U.S. Patent Application 2009 / 0128771, entitled "Fabrication Methods for Liquid Crystal Display Devices" (Yang et al.), which describes a roll-to-roll method for manufacturing components using a "patterned enclosed structure" including multiple strips for dividing the liquid crystal. Another method uses patterned micropolymer spacers to contain the LC material in a small confined space. For example, in one method described in Wen-Tuan Wu et al., "P-55: Cell filling of Flexible Liquid Crystal Displays Using One Line Filling and Tilted Roller Pressing," SID 07 Digest, p. 393 (2007), micropolymer spacers 10 μm wide by 170 μm long by 3 μm high are formed on a substrate to contain the liquid crystal material in a small rectangular space, thereby enabling the manufacture of large components. Other examples of patterned spacers include the method of US Pat. No. 7,850,867 to Liang et al., entitled "Compositions for liquid crystal display."

[0012] Other approaches include providing a "support layer" made of a material capable of absorbing or bonding the LC material so that the LC layer is dimensionally stable in thickness and of sufficient thickness to perform. See US Patent No. 5,868,892.

[0013] Although plastic substrates provide themselves for roll-to-roll manufacturing with reduced cost and increased manufacturing efficiency, previous efforts to achieve a roll-to-roll continuous manufacturing method for various flexible displays have not been successful. Specifically, the manufacture of large surface area flexible displays is still illusive. One reason is that in liquid crystal devices (such as displays or optical devices), it is necessary that the liquid crystal layer (that is, the liquid crystal material together with any dyes mixed therein) has an optimal uniform thickness, because changes in thickness cause changes or gradual changes in the optical properties of the liquid crystal device. In addition, the changed thickness of the liquid crystal material will cause corresponding changes in the electrical properties (such as capacitance and resistance) of the liquid crystal material, thereby further reducing the uniformity of the liquid crystal device, especially the liquid crystal device with large size. The changed electrical properties of the liquid crystal material can also cause corresponding changes in the effective electric field applied to the liquid crystal material. In addition, in response to a constant electric field, regions of the liquid crystal material with different thicknesses will respond differently. Therefore, there should also be an optimal spacing of the electrodes through which the electric field is applied to the liquid crystal material. In order to maintain this optimal thickness and spacing, a fairly tight tolerance must be maintained. In order to maintain tight tolerances, there is a limit on the size of devices using such liquid crystals, as it is quite difficult to maintain tight tolerances over large surface areas. In addition, the amount of liquid crystal must be controlled, as is the case with vacuum-based processing. However, in roller-based plastic processing, it is best to avoid the presence of a vacuum for the reasons stated above.

[0014] For these reasons, satisfactory large-scale single-element liquid crystal devices (such as solar windows or windows) have not yet been manufactured, mainly because of the fluidity of these liquid crystals, that is, the tendency of the material to flow, thereby forming areas with different material thicknesses, which in turn leads to uneven optical and electrical properties.

[0015] In general, it has been conventionally believed that it is not possible to manufacture flexible elements filled with a fluid electro-optical mixture such as a liquid crystal using roll-to-roll, roll-to-sheet, roll-to-part, or continuous manufacturing methods (collectively referred to herein as roll-to-roll), except using the various encapsulation / patterning spacer methods described herein. This is because of the difficulties of working with flexible plastics: the need to maintain a controlled distance between the two substrates at 5-20 μm, with only + / - 1-2 μm variation (tolerance); the precision required to fill the controlled gap between the top and bottom substrates with an amount of liquid crystal sufficient to fill the entire gap without forming bubbles or defects; and the fluid nature of the liquid crystal, which necessitates the use of polymerization or encapsulation to stabilize the LC and / or the use of spacers that can form discrete patterns, all of which result in undesirable "haze".

[0016] Therefore, there remains a need for efficient fabrication methods for flexible, plastic, substantially polymer-free liquid crystal devices. Summary of the invention

[0017] Disclosed herein is a continuous method for producing a flexible element unit enclosed by a frame-like boundary seal, wherein two flexible substrates separated by a controlled distance maintained by a non-patterned spacer are assembled together and roll-filled with an electro-optical material (EOM) during the continuous production process. The terms "roll-filled" and "roll-filled" as used herein refer to using one or more laminating rollers to fill the space between the flexible substrates or the active area of ​​the element with the EOM so that the electro-optical material completely fills the controlled distance between the substrates. In some embodiments, the roll-filling is achieved without the use of a vacuum (vacuum-free method).

[0018] In one embodiment, the method includes: providing two continuous sheets of flexible plastic material to form a first (e.g., bottom) substrate and a second (e.g., top) substrate; depositing an electro-optic material on the first substrate; using a laminating roller to mate the second substrate with the first substrate and to roll-fill the element (or sheet) with the electro-optic material such that the electro-optic material fills the controlled distance between the first and second substrates. The border sealant may be applied prior to the step of depositing the EOM or after the EOM has been deposited.

[0019] In some embodiments, a border sealant is applied prior to the roll-to-fill step, so the method includes: the step of applying a border sealant to the first substrate and / or the second substrate or both substrates prior to depositing the EOM; and the step of curing the border sealant to form the border seal before or after the roll-to-fill step. In this method, the electro-optic material may be deposited on an area outside the perimeter of the border sealant ( Figure 3A As an alternative, the electro-optical material may be deposited within the perimeter of the boundary seal ( Figure 3B In other embodiments, the EOM may be deposited in one or more shapes both outside and inside the perimeter formed by the boundary sealant. Figure 3C -F). This method may have a further step of cutting the flexible element unit from the two continuous flexible plastic material sheets using a mechanical cutter (e.g. an xy-cutter or a punch cutter), or a laser cutter, or a combination thereof, or any other cutting / separating technique known in the art.

[0020] In some cases it may be advantageous to print the boundary sealant on both the top substrate and the bottom substrate. In this embodiment, during the roll-to-roll process, the EOM flows between the top boundary sealant and the bottom boundary sealant rather than strictly on the bottom boundary sealant. This ensures that the boundary sealant can contact each substrate surface. This promotes adhesion and stability of the seal.

[0021] In some cases, more than one boundary sealant may be applied, for example, two or more types of adhesives may be employed to provide the boundary seal, each adhesive providing a different function, for example, an adhesive function versus a non-interacting function.

[0022] In other embodiments, the EOM is applied first, followed by the border sealant and roll-filling the element. In one embodiment, the border sealant is cured before the roll-filling step. In another embodiment, the border sealant is cured after the roll-filling step.

[0023] When a border sealant is present, it has a viscosity of >1000 centipoise (cP), >2000 cP, >3000 cP, >4000 cP, or >5000 cP. In some embodiments, the viscosity is less than 10,000 cP, 20,000 cP, 30,000 cP, 40,000 cP, 50,000 cP, 60,000 cP, or 70,000 cP. In some embodiments, the ratio of the border sealant viscosity to the EOM viscosity is greater than 5, 6, 7, 8, 9, 10, 20, 30, 40, or 50.

[0024] In some embodiments of this method, the electro-optic material does not chemically interact or only minimally interacts with the border sealant.In some examples, multiple (ie, more than one) border sealants may be applied to one or both substrates.

[0025] In another embodiment, a boundary seal is formed after the roll-fill step using a laser or heating element or a similar welding method for sealing around the roll-fill element. The laser can melt the top substrate and the bottom substrate together to form a continuous seal around an active area. The laser can also be configured to cut separate elements from a sheet while forming the seal. The steps in this method include: providing two continuous sheets of flexible plastic material to form the first (bottom) substrate and the second (top) substrate; depositing an electro-optical material on the first (or second) substrate; using a laminating roller to match the second substrate to the first substrate to form an element filled with the electro-optical material and having a controlled distance maintained by a non-patterned spacer; then laser cutting a shape to form a boundary seal and to separate the flexible element unit from the two continuous flexible plastic sheets. In this method, a boundary sealant is not applied before the roll-fill step. Instead, the boundary seal is formed after the roll-fill step.

[0026] In any of the methods described above, the flexible plastic sheets may be pre-coated with a plurality of non-patterned spacers, or the method may further include a step of applying the non-patterned spacers to the first substrate, the second substrate, or both. In other embodiments, the spacers may be deposited in the electro-optical material. Alternatively, the spacers may be deposited on an orientation layer on the first substrate, the second substrate, or both.

[0027] In some examples, the spacers may be printed onto one or both substrates. The distribution of the spacers must be such that they produce minimal or no diffraction pattern. Thus, the term "non-patterned spacer" refers to a spacer having a random or non-diffraction-producing pattern.

[0028] Furthermore, in most of the examples described herein, the spacer count (or density of the spacers) remained >80 / mm2.

[0029] In any of the embodiments described above, the substrates may include a conductive layer (e.g., indium tin oxide or ITO) for applying voltage or current to the electro-optical material. Thus, the sheets of flexible plastic may be pre-coated with a conductive layer, or the method may further include a step of applying a conductive layer to the first and second substrates.

[0030] The first substrate and the second substrate may also include an orientation layer to assist the arrangement of the EOM molecules. The orientation layer may be already present on these continuous flexible plastic material sheets (pre-coated). As an alternative, the method may include a step of depositing the orientation layer on the first substrate, the second substrate, or both. The orientation layer may be applied to the entire surface of the first substrate sheet or the second substrate sheet, or selectively applied to a selected active area on one or both of the first substrate and the second substrate. The active area refers to the area on the substrate that will be filled with the electro-optical material and defined by the boundary seal. Various techniques may be used to achieve selective application, for example, screen printing, inkjet printing, flat coating, roller pressing, hot pressing, phase separation from a mixture, or other methods known in the art. In some cases, this is a self-assembled monolayer that can produce a desired arrangement.

[0031] In some embodiments, the alignment layer can include spacers that maintain the controlled distance between the substrates.

[0032] The electro-optical material includes any material that can be changed by applying an electric current or voltage. Examples include liquid crystals, electrochromic materials, SPDs, etc.

[0033] In some embodiments, the electro-optic material is generally non-polymerizable and non-encapsulated, or does not contain more than 1%, 2%, 3%, 4%, 5% of polymerizable material. In some instances, the electro-optic material includes a non-polymerizable, non-encapsulated liquid crystal or a liquid crystal-dye mixture. In some instances, the electro-optic material is a guest-host dichroic dye-liquid crystal mixture. In some instances, the EOM is non-discrete. In other embodiments, especially where the flexible element is larger, in addition to the non-patterned spacers, the EOM can be divided / split into multiple discrete areas by applying partition walls to assist in maintaining the controlled distance between the substrates.

[0034] The electro-optical material may be deposited in a continuous film on the first substrate in the form of drops, lines or shapes or sheets using any deposition method known in the art. (Figures 3-5)

[0035] When the EOM contains a liquid crystal mixture, the substrates may be coated with an orientation layer and the method may include a step of treating the orientation layer to allow proper alignment of the liquid crystal molecules (and / or dyes) with the substrates. "Treatment" as used herein includes any number of ways known in the art for producing the desired arrangement of the liquid crystal. For example, the orientation layer polyimide (PI) may be physically wiped with a soft cloth. As an alternative, while the PI is being dried, it may be aligned using an air jet. It is also known that photo-alignable orientation layers cause alignment with UV light or the like.

[0036] In some embodiments, the flexible element unit is an optical device. An "optical device" refers to a device having the following optical properties: suitable for enabling a user to view through the device without significant distortion of an image viewed through the device. Thus, an optical device is different from a traditional display because typically a user does not view images through a display. Examples of optical devices include glasses, goggles, safety glasses, sun windows, windows, fenestrations, etc. In some examples, the optical device has a haze value of less than 15%, 10%, 7%, 5%, 3%, 2% or 1%.

[0037] In some examples, the flexible element unit is an optical device comprising a liquid crystal-dichroic dye mixture that can be switched between a high transmission "transparent" state and a low transmission "dark" state under the application of different voltages. Such guest-host liquid crystal-dye mixtures are well suited for the fabrication methods disclosed herein because the element has a relatively high tolerance for variations in the element gap.

[0038] One of the many advantages of the method of the invention described herein is that it can be performed as a vacuum-free method. However, it can also be performed under vacuum if desired. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a schematic cross-sectional view of a flexible element unit.

[0040] Figure 2 is a schematic diagram of one embodiment of a roll-fill fabrication method for a flexible component unit in which the border sealant is applied prior to the roll-fill step.

[0041] Figure 3A -E are schematic diagrams of various examples of placement of the EOM relative to the boundary seal in a roll-to-fill process, the figures showing examples of various EOM deposition patterns.

[0042] Figure 4 is a schematic diagram of another embodiment of a roll-fill method forming the boundary seal after the roll-fill step.

[0043] Figure 5 shows that Figure 4 The method shown is used together with multiple examples of various EOM deposition patterns.

[0044] Figure 6 is a schematic diagram of an example of a single roll filling method.

[0045] Figure 7is a schematic diagram of an example of a double roll filling method.

[0046] Figure 8 is a schematic diagram of an example of a vertical roll filling method. DETAILED DESCRIPTION

[0047] Disclosed herein is a method of producing a flexible element unit that is closed by a boundary seal (edge ​​sealed) and filled with an electro-optical material (EOM). In general, the method includes: providing two continuous sheets of flexible plastic material to form the first (e.g., bottom) substrate and the second (e.g., top) substrate; depositing or dispensing an amount of electro-optical material on the first substrate; and using a laminating roller to (a) mate the second substrate with the first substrate and (b) roll-fill the element with the electro-optical material so that the electro-optical material fills a controlled distance between the first substrate and the second substrate.

[0048] Figure 1 1 is a schematic diagram of a flexible component unit 10. Component 10 includes a top flexible plastic substrate 12 and a bottom flexible plastic substrate 14, respectively. According to the application, these substrates can be coated with a conductive layer 16. Optically transparent conductive layers include indium tin oxide (ITO), conductive polymers, conductive nanowires, etc. As an alternative or in addition, these substrates can also be coated with an orientation layer 18, such as polyimide, etc.

[0049] The flexible substrates 12, 14 are made of a transparent flexible plastic suitable for constructing a flexible element unit, such as polycarbonate (PC), polycarbonate and copolymer blends, polyethersulfone (PES), polyethylene terephthalate (PET), cellulose triacetate (TAC), polyamide, p-nitrophenyl butyrate (PNB), polyetheretherketone (PEEK), polyethylene terephthalate (PEN), polyetherimide (PEI), polyarylate (PAR) or the like as known in the art. Many of these substrates are commercially available from, for example, Mitsubishi Plastics or Teijin DuPont Films and are standardly equipped with various coatings, such as hard coatings.

[0050] The flexible substrates 12, 14 are separated by a controlled gap or distance maintained by spacers 24. The volume between the substrates is filled with an electro-optic material 26.

[0051] These spacers 24 are used to maintain a controlled distance or gap between these substrates. In some embodiments, the size of the controlled gap is 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 30, 40, 50, 60, 70, 80, 90 or 100 μm. In some instances, the size of the controlled gap is preferably 5, 6, 7, 8, 9 or 10 μm. A "controlled" gap or distance means that the variation of the distance between these substrates should be kept less than 30% of the spacer diameter (which determines the controlled gap) on average. In some instances, the variation is less than 25%, 20%, 15%, 10% or 5% of the spacer diameter.

[0052] Generally, two types of spacers are used to maintain a controlled distance between substrates. One is a "patterned spacer", which is a spacer that is purposefully placed or formed on a substrate to form a specific repeating geometric pattern, or they are formed using a photolithography or polymerization or similar method known in the art and produce a diffraction pattern. Examples include polymer walls. Other examples include the patterned spacers used in "P-55: Element Filling of Flexible Liquid Crystal Displays Using Single Line Filling and Oblique Rolling" by Wu Wentuan et al., SID 07 Abstracts, page 393 (2007). Wu et al. used a photolithography technique to form patterned micropolymer spacers (10 μm wide × 170 μm long) that were elongated to form long liquid crystal columns. Typically, these spacers have a length and width greater than the element gap, that is, they have a long side to element gap aspect ratio of >20 in a mode that can produce a visible pattern in the device.

[0053] In contrast to the above, the method of the present invention uses "non-patterned spacers" to maintain the controlled distance between these substrates. As defined herein, "non-patterned spacers" are spacers that are randomly placed (e.g., sprayed on) or printed at locations where they are positioned in a manner that does not produce optical aberrations, such as diffraction patterns, etc. The non-patterned spacers of the present application can be spherical or they can be elliptical, with an aspect ratio (length / width) of less than 10 / 1 or 5 / 1, 4 / 1 or 3 / 1. These spacers are used to maintain a distance between these substrates at 3-100 μm, preferably 4-20 μm.

[0054] Another difference in the method described here is the spacer count or density. The method works well when the substrates are covered with smaller spacers having a greater density than when longer patterned spacers are placed in selected locations. For example, in some embodiments, the spacer count is maintained at >80 / mm2 (mm 2 ).

[0055] In some embodiments, the spacers 24 can be pre-applied to the substrates (e.g., the continuous sheets are pre-coated with spacers) or can be applied to the substrates in the roll-to-roll process, for example, sprayed onto or applied into a layer in which the spacers are randomly arranged or arranged in a non-diffractive production pattern. The spacers can be dispersed using a wet or dry method as known in the art. They can also be placed in the orientation layer in a pre-coating process or in the roll-to-roll manufacturing process. The spacers can also be coated with an adhesive layer.

[0056] Spherical spacers differ from the spherical encapsulated liquid crystals, such as those described in patent application PCT / US1982 / 001240 (WO / 1983 / 001016) to FERGASON, entitled "Encapsulated Liquid Crystal and Method," in that they do not encapsulate any volume of the EOM.

[0057] In some embodiments, spacers 24 may be deposited within or as part of the orientation layer, such that the spacers are applied when the orientation layer is applied to one or both substrates. In other embodiments, spherical spacers 24 may be integrated into the electro-optical material deposited on the substrates.

[0058] The component 10 further includes a boundary seal (edge ​​seal) 27 / 28 that contains the EOM inside the component and forms a barrier between the external environment and the EOM, thereby preventing the EOM from flowing out of the component and preventing environmental factors (air, moisture, debris) from entering the component. In some examples, the boundary seal is formed by applying a boundary sealant to one or more of the substrates, which when the substrates are brought together and cured will form the boundary seal around the electro-optical material contained within the component. Figure 1 The boundary sealant is shown as it is applied to the substrates. Figure 1 In one aspect, a boundary sealant 27 seals the flexible substrates 12, 14 together. Alternatively, the boundary seal arrangement may be as shown on the other side of the element, with a boundary sealant 28 sealing the gap between the orientation layer and / or conductive layer. The particular arrangement will depend on the timing and method of application of the boundary sealant.

[0059] In some embodiments, during the roll-to-roll filling process, the boundary sealant has a viscosity of less than 70,000 cP and greater than 1000 centipoise (cP), 2000 cP, 3000 cP, 4000 cP or 5000 cP. The boundary sealant includes a thermal adhesive and a thixotropic adhesive, the thermal adhesive reduces viscosity when heat is used to assist bonding, and the thixotropic adhesive changes viscosity in response to a corresponding pressure. In some embodiments, the ratio of the boundary sealant viscosity to the EOM viscosity is greater than 5, 6, 7, 8, 9, 10, 20, 30, 40 or 50. In some instances, a boundary sealant with a viscosity of 6000 cP has been successfully used. The viscosity of the boundary sealant affects the integrity of the element because if the viscosity of the boundary sealant is too low, it may mix with the EOM during processing, thereby promoting chemical interaction with the liquid crystal or the flow of the liquid crystal and deposition in an undesirable position on the substrate surface during the roll-to-roll filling process. If the boundary sealant is too viscous, the controlled gap or distance around and adjacent to the boundary seal will not be uniform.

[0060] In some instances, it is advantageous if the boundary sealant material experiences minimal or no chemical interaction with the electro-optical material 26 over a long period of time (typically more than 6 months, more than 1 year, more than 2 years, etc.). For example, we have found that over time (e.g., six months or longer), the sealant may deteriorate or interact with the electro-optical material (e.g., liquid crystal) inside the element, thereby forming a plurality of micropores that allow air to penetrate into the element, thereby forming bubbles or defects. In some instances, it is advantageous if the boundary sealant is non-porous to the EOM or its components. For example, we have found that porous boundary sealants reduce the life of the device by absorbing some of the EOM components. Some boundary sealants have exhibited chemical interactions in the form of unwanted fading of the liquid crystal near the boundary seal. In some instances of chemical interactions, the boundary sealant itself becomes faded. These interactions are undesirable.

[0061] The border sealant can be applied using any technique known in the art, such as using a brush, roller, film or ball, spray gun, coating gun, screen printing, inkjet printing, flexographic printing, flat coating, roller pressing, hot pressing, etc. All of these can be done manually or can be automated into a machine, or a combination thereof. The border sealant can be a suitable adhesive (UV, heat, chemical, pressure, multi-component epoxy resin and / or radiation curing), a sealant based on polyisobutylene or acrylate, etc., or a pressure sensitive adhesive, a binary adhesive, a moisture curing adhesive, etc. Other types of border (edge) seals can be made up of metallized foil or other isolation foils adhered to the edge of the element. It has been found that hybrid radiation sealants and heat-curing sealants (i.e., UV that can be cured by thermal post-baking) provide certain advantages. For example, Threebond 30Y-491 material (from Threebond Corporation, Cincinnati, Ohio) is particularly useful because of its favorable water vapor barrier properties, low viscosity at high temperatures for easy deposition of the edge seal material, good wetting properties, and manageable curing properties. Those skilled in the art and familiar with advanced sealants will be able to identify other sealants that provide comparable performance.

[0062] Element 10 is filled with an electro-optical material (EOM). The electro-optical material can be any material that passes through the element in response to an electric field applied to the element so as to have the desired operating characteristics expected of the device, and includes any material that can be changed by applying an electric current or voltage. For example, the EOM can be one of a liquid crystal material, an electrochromic material, a suspended particle device (SPD), or a combination thereof with other additives such as dyes (dichroic dyes, polychromic dyes, etc.), wherein the electro-optical material can be changed by applying an electric current or voltage. In a preferred embodiment, the EOM is a guest-host liquid crystal-dichroic dye mixture.

[0063] In some embodiments, the electro-optic material is generally non-polymerizable, non-encapsulated, and non-discrete. Therefore, the EOM material does not include polymerized or encapsulated liquid crystal components, such as PDLC, PELC, PSCT, PNLC, NCAP, etc.

[0064] As used herein, "non-polymerizable" means an EOM composition that does not include any chemical components (eg, polymers) in an amount necessary to dimensionally stabilize the EOM layer by changing the phase of the material to a solid, semi-solid, or gel.

[0065] "Non-discrete" means an EOM that is not divided into discrete, separate compartments by encapsulation, polymer walls, polymer networks, patterned spacers, and the like.

[0066] "Non-encapsulated" means an EOM that is not contained within the confined space or internal volume of a package. A package refers to an enclosure or medium that encloses a quantity of EOM material (such as liquid crystal), such that an "encapsulated EOM" is a quantity of EOM enclosed or contained in an encapsulation medium (e.g., a polymer package). These packages may have a spherical shape or may have any other suitable shape. Encapsulated EOMs (e.g., encapsulated liquid crystals) are manufactured so as to prevent them from flowing. Examples of encapsulated EOMs include polymer dispersed liquid crystals (PDLCs) comprised of droplets of liquid crystals within a polymer network.

[0067] "Reel-to-reel process" means the entire overall process that these substrates undergo from being unrolled from their respective reels to the manufacturing of the component.

[0068] For example, one method of microencapsulation is described by Ferguson in patent number 4,435,047 entitled "Encapsulated Liquid Crystal and Method" (1984) and patent application PCT / US1982 / 001240 (WO / 1983 / 001016) entitled "Encapsulated Liquid Crystal and Method". In this method, a resin material is used to encapsulate the liquid crystal (LC) material so as to form curved spherical packages containing discrete amounts of LC material. These are accomplished by mixing the LC material and an encapsulation medium (e.g., a resin) together, in which the LC material will not dissolve and allow the formation of discrete packages containing the LC material. In the microencapsulation, the liquid crystal is mixed with a polymer dissolved in water. When the water is evaporated, the liquid crystal is surrounded by the polymer. A large number of tiny "packages" are produced and distributed throughout the bulk polymer. The material made by encapsulation is called NCAP or Nematic Curved Alignment Phase.

[0069] There are other methods for preparing PDLC, PSCT, PNLC, such as phase separation, such as phase separation caused by polymerization (PIPS). In the case of PIPS, as the molecular weight of the polymer chain grows, the LC is encapsulated into micron-sized droplets by the solid polymer wall, and the droplets of LC are excluded from the body via phase separation. Once encapsulated, the liquid crystal cannot flow or leak out between these substrates when these substrates are cut. This method is described in the following literature: for example, in Schneider et al., SID International Symposium Technical Paper Abstracts, Vol. 36, p. 1568 (2005); and Schneider t's "New Developments in Flexible Cholesteric Liquid Crystal Displays" Emerging Liquid Crystal Technologies II SPIE Conference Proceedings, Vol. 6487, 64870J (2007).

[0070] When the electro-optical material comprises a "guest-host" liquid crystal-dye mixture, the mixture comprises a certain amount of one or more dichroic dyes "guests" mixed in a liquid crystal "host" solution. The liquid crystal "host" molecules have an orientation axis that can be changed by adjusting the voltage applied to these substrates. The "guest" dye mixture comprises one or more dichroic dyes, which are dissolved in the liquid crystal host, aligned with the orientation of the liquid crystal molecules, and its absorption of polarized light depends strongly on the polarization direction relative to the absorption dipole in the dye molecule. The applied voltage causes switching between a first state (in the first state, the guest-host orientation allows maximum light transmission, referred to as a "transparent state") and a second state (in the second state, the guest-host orientation allows minimum light transmission, referred to as a "dark state") and a combination of multiple intermediate states between the fully transparent state and the fully dark state. Depending on the composition of the guest-host mixture, the transparent state can occur at zero voltage (disconnected state). As an alternative, the mixture can be formulated so that zero voltage (disconnected state) corresponds to a dim (minimum transmission) state.

[0071] Elements comprising guest-host liquid crystal-dye mixtures are particularly suitable for fabrication according to the methods described herein because they have a larger tolerance for variations in the element gap, i.e., the elements are more tolerant and can operate well even with small variations in the element gap (within allowed limits, such as + / - 5%, 10%, 15%, 20%, 25% or even 30%) compared to elements that rely on phase retardation (such as polarizer-based LC devices), where the tolerance or variation in the element gap must be kept to <1%.

[0072] In some embodiments, the guest-host liquid crystal-dye mixtures described above are used to attenuate light in an optical device. An "optical device" refers to an element that is a primarily transmissive device through which a user can see objects (e.g., a pair of glasses, goggles, safety glasses, or a window).

[0073] A device having a transparent (maximum transmission) state at zero voltage (off state) can be realized, for example, where the guest-host liquid crystal-dye mixture has a vertical alignment (i.e., perpendicular to the substrates) when no voltage is applied, the liquid crystal host has a negative dielectric anisotropy and the dichroic dye has a positive dichroism (i.e., has a maximum absorption when the polarization is parallel to the long molecular axis of the dye molecule and has a minimum absorption when the polarization is perpendicular to the long axis). In such a device, when voltage is applied (on state), the guest-host mixture adopts a planar or homogeneous arrangement (i.e., parallel to the substrates) and becomes minimally light-absorbed (dark). Such an arrangement can be used, for example, in protective goggles, protective glasses, goggles, etc., where it may be desirable to "darken" the device in response to an applied voltage when strong light is present. Other applications include windows (vehicles, buildings, aircraft, etc.) and sun / moon windows, etc.

[0074] In other examples, a reverse alignment can be achieved such that the guest-host liquid crystal-dye mixture can have a planar alignment (homogeneous) in the dark state when the applied voltage is disconnected, and a homeotropic alignment in the transparent state when voltage is applied. This can be achieved by using a planar surface treatment for the alignment layers in combination with a dye having positive dichroism and a liquid crystal material having positive dielectric anisotropy. This arrangement can be used, for example, in windows or sun windows where it is desired that the device be normally in the "dark" state, but be able to switch to the transparent state by application of voltage.

[0075] Finally, the element 10 may be connected to a control circuit 30 for applying an electric field or voltage to the element. The voltage source may be alternating current or direct current.

[0076] Figure 2An example of a roll-to-roll filling method for manufacturing component 10 is shown in FIG. In this example, two flexible plastic rolls 100, plastic 102 are used to form a top substrate 104 and a bottom substrate 106, respectively. These continuous plastic sheets are placed on multiple sets of rollers (108), which rotate and move the plastic sheets toward a set of laminating rollers 110, 110'. In this example, each continuous flexible plastic sheet is previously coated with an ITO conductive layer. A set of applicators 112, 112' is used to apply a polyimide orientation layer 116, 116' to the top substrate 104 and the bottom substrate 106. A spray applicator 117 is used to apply a layer of spherical spacers 118 to the bottom substrate 106.

[0077] Figure 2 The spacers are shown applied to the bottom substrate, but in other examples, the spacers may be applied to the top substrate, or to both the top and bottom substrates. Spacers may be applied to a single substrate roll or two substrate rolls prior to the roll-to-roll process. Spacers 18 may also be applied in the roll-to-roll process using any method known in the art, including wet or dry spraying, atomization, printing, or wet coating in solution.

[0078] In some examples, the spacers may be embedded in the alignment layer and applied as part of the alignment layer. In still other examples, the spacers may be embedded in the EOM and applied as part of the EOM when the EOM is deposited on a substrate.

[0079] A screen printer 119 prints a border sealant pattern 120 on the bottom substrate 106 as the substrate rolls in direction A. In some embodiments, the screen printer is a rotary screen printer, and the top substrate, the bottom substrate, or both the top and bottom substrates are printed with a border sealant.

[0080] A stripe or line of EOM (eg, liquid crystal / dye mixture 124) is deposited onto the bottom substrate 106 using a deposition needle 125, near but outside the area formed by the border sealant 120. A method of depositing EOM 124 before the border sealant 120 is also contemplated.

[0081] Lamination rollers 110, 110' are then used to bring the top substrate 104 and bottom substrate 106 together and "match", while the pressure from the rollers pushes the EOM 124 to roll over the boundary seal 120 and into the "active" area inside the perimeter of the boundary sealant 120, thus forming an element 130 filled with the EOM 124. The "matching" of the top and bottom substrates brings the top substrate 104 into contact with the boundary sealant 120 and into contact with the spacers 118, thereby separating the top and bottom substrates by the width of the spacers. The spacers 118 maintain a controlled distance or "gap" between the top and bottom substrates, which is then filled with the EOM 124.

[0082] Finally, the boundary sealant 120 is cured by a curing device 128, and the element 130 is cut and removed from the rolled plastic sheet. However, it is possible to first cut and separate the element and then use UV light, heat, pressure, chemical interaction, moisture, or their combination or any method for curing the boundary sealant to cure the boundary seal. The section of the substrate that matches to include multiple elements can be cut into a thin sheet that includes multiple elements. These elements can be cut off mechanically or optically by other methods subsequently. Mechanical methods include punching, utilizing xy blades or scissors to cut, etc. Optical cutting includes laser cutting, etc.

[0083] The electro-optic material may be deposited on the inside or outside of the perimeter of the boundary seal, such as Figure 3A-3B In other examples, the EOM can be deposited in various areas inside or outside the boundary sealant ( Figures 3C-3F ). The electro-optical material can be selectively deposited in the form of drops, lines or shapes, as shown in FIG. 3 .

[0084] If part or all of the EOM is deposited outside the perimeter of the boundary sealant, the pressure from the laminating roller causes the EOM to roll over the boundary sealant to fill the active element area. Therefore, it is preferred to have minimal interaction between the electro-optical mixture and the sealant so that one does not interfere with the function of the other.

[0085] Boundaryless processing

[0086] exist Figure 4In another embodiment of the manufacturing method shown in , no boundary seal is applied before the roll-to-fill step. Instead, a certain amount of EOM 270 is applied to a substrate 272, and then two substrates 272, 274, which have been pre-coated as required, are brought together and roll-to-filled with the EOM, with their spacing maintained by multiple spacers on one or both substrates. The roll-to-fill step can be performed by a single roller or by dual rollers.

[0087] An edge seal 278 is formed by a laser cutting or laser welding device 279, which is used to simultaneously cut a shape and form a boundary seal, and form and separate the EOM-filled flexible element unit 280 from the remainder of the continuous plastic sheet. Alternatively, a two-step process can be used in which the substrates are first welded together without separating the element from the mating substrates, and then the element is cut and / or separated from the remainder of the sheet. The welding step can be performed using laser, heat, or a combination of both.

[0088] FIG5 shows Figure 4 Various patterns of EOM deposition in the borderless approach are shown in . As can be seen, the EOM is deposited in discrete patterns or as "sheets" covering a large portion of the area on one (or both) substrates.

[0089] Any of the methods described herein can be used to fabricate large area devices, i.e., devices with a surface area greater than 30 cm 2 、40cm 2 or 50cm 2 Any object with a surface area of ​​​​more than 10cm or any component with a length of more than 10cm.

[0090] In some embodiments, the process is performed without the use of a "film guide". A "film guide" is a rigid sheet used to generally guide the top substrates into proper alignment. Such a top film guide is described in Wu et al., "P-55: Element Filling of Flexible Liquid Crystal Displays Using Single Line Fill and Oblique Rolling", SID 07 Abstracts, page 393 (2007). However, the use of the film guide has the following disadvantages: such a "guide" may easily touch and scratch the top substrate, thereby scratching the top substrate or scraping off coatings such as the conductive layer and / or orientation layer.

[0091] The method described herein can also be implemented without using a "plate" to transport one or two substrates. For example, in the literature of Wu et al., the bottom substrate is fixed to a "platform" or a plate. This plate can be a limiting factor in the size of the component being manufactured. In order to manufacture a large component (e.g., a display, a window), a large plate is required. This takes up valuable space in a clean room environment. In addition, each component of different sizes will require a different size plate. In addition, using a platform to move the substrate is problematic in the manufacture of large flexible components because the gap between these substrates needs to be maintained constant with a low variation (e.g., a tolerance of + / -15% or 1-3 μm) for the component to operate correctly. But the platform itself is often not completely flat, so maintaining this low tolerance becomes more difficult as the component becomes larger.

[0092] When the roll-to-fill method described herein does not use a plate or platform, the movement of the plastic substrates is made possible by the movement of the rollers. Thus, the method can be adapted for quickly and easily manufacturing components of various sizes. For example, a component of one length can be manufactured and the next component can be a different length without reprocessing steps and without material waste.

[0093] This matching (lamination) step between these two substrates can be realized using one or two rollers. When using two rollers, the pressure between these two rollers and or the gap is used to laminate these two substrates. These rollers can be made of rubber, metal or their combination, wherein for example, a roller has a rubber outer layer and another roller has a metal outer layer. It is well known in the art that in roll-to-roll production, the diameter and plastic strength of this roller must be tuned to avoid damage.

[0094] When the lamination is achieved using a single roller, the tension in the web is the main source of pressure. In an example, the two substrates are allowed to move around a roller each, and the lamination pressure is achieved due to the tension on the roller.

[0095] These substrates can be pre-laminated to a protective film to prevent scratches from the process, or to increase its thickness or change the tensile strength. In addition, these substrates can be pre-treated with functional coatings such as anti-fog layers, anti-reflection layers, hard coatings, sliding layers, etc.

[0096] In the following examples, we describe how to manufacture flexible liquid crystal elements according to the methods described herein.

[0097] Example 1

[0098] ● Two substrates pre-coated with ITO and an alignment layer PI are placed on a set of rollers, one to form a top substrate and the other to form a bottom substrate

[0099] The bottom substrate is sprayed with non-patterned spacers,

[0100] ● A border sealant is printed onto the bottom substrate

[0101] ● A line of liquid crystal / dye mixture is deposited outside the perimeter of the border sealant

[0102] ● A roller is used to bring the top and bottom substrates together and roll-fill the active area inside the perimeter of the border sealant with the liquid crystal / dye mixture

[0103] ● UV cure the border sealant to form an edge seal

[0104] Example 2 - Single Roller

[0105] exist Figure 6 In another example shown in , the bottom substrate can be placed and fixed to a moving plate 150 and a single roller (110') is used to roll-fill the components 120. In this example, the moving roller 110' can cause the plate and / or the bottom substrate to move in direction A, or the moving plate 150 moves the bottom substrate and causes the roller to roll in direction B, thereby pairing the substrates and roll-filling the components.

[0106] Example 3 - Dual Rollers (Top and Bottom)

[0107] In this example ( Figure 7 ), a set of top rollers 200 and bottom rollers 202 are used to mate or pair a top flexible substrate 204 with a bottom flexible substrate 206. A border sealant 208 is applied to the bottom substrate 206. The rollers 200, 202 pull the flexible substrates across the rollers in the web direction A. While rolling, the deposited electro-optical mixture 210 fills the controlled gap formed between the two substrates 204, 206 while they are paired.

[0108] This method can be employed in a continuous roll-to-roll process. There is no need to carefully measure the amount of OEM deposited on the substrates, as the method works equally well when using more OEM, resulting in a certain amount of EOM flowing over the boundary seal during the roll-to-roll fill step. This is an advantage over previous manufacturing methods that required depositing a very precise amount of OEM required to fill the component, such that the component will be completely filled but the boundary sealant will only minimally contact the LC.

[0109] Example 4 - Dual Rollers (Left and Right)

[0110] In this example, a set of left rollers 250 and right rollers 252 are used to mate flexible substrate 254 with flexible substrate 256 while moving the substrates in a vertical downward direction ( Figure 8 ).

[0111] Essentially, the top and bottom rollers from the previously described method are now placed side by side. The difference is that in this new arrangement, the substrates 254, 256 are brought together from two different horizontal directions E and F, respectively. The rollers pull the flexible substrates across the rollers in a vertical downward web direction G. As they roll, the deposited EOM fills the controlled gap formed between the two substrates while they are paired, as previously described. This setup will make it simpler to print or pattern any orientation layers on these substrates, and / or allow multiple additional processing steps to be performed on one or both plastic sheets / substrates.

[0112] Example 5

[0113] In another example, two substrate rolls are placed on rollers separately. Each roll is 3 mil PET from Mitsubishi Plastics. These substrate rolls are pre-coated with a conductive layer, i.e. ITO, manufactured by Materion. Subsequently, a polyimide orientation layer of 5661 from Nissan Chemicals is used to coat these substrates coated with ITO. Shinshikyu EW plastic balls (Hiko Industrial Ltd., Hong Kong) with a diameter of 6 microns are mixed into the polyimide during the coating process and are present in at least one of these substrate rolls. These rollers unfold these substrate rolls during the roll-to-roll process. An unfolded roll becomes the top substrate, and the second becomes the bottom substrate. These substrates move at a coil speed of about 0.5 inch / second to about 10 inches / second throughout the roll-to-roll process. Each substrate has a corresponding border sealant printer. In this case, these printers are rotary screen printers. These rotary screen printers print the boundary sealant of model Loctite 3108 on each effective surface of the top substrate and the bottom substrate. The effective surface is the surface that will contact the EOM in the finished element. A rotary printer will print a boundary sealant with a height of about 5 microns to about 100 microns, preferably about 5 microns to about 40 microns. After rotary printing, EOM is deposited on the effective surface of the bottom substrate by a syringe and a needle dispenser. The EOM is a guest-host dichroic dye-liquid crystal mixture, model AMI577. A group of top laminating rollers and bottom laminating rollers match the top substrate and the bottom substrate together, so that the top boundary sealant is aligned with the bottom boundary sealant and the EOM contacts both the top effective surface and the bottom effective surface, and fills the entire internal boundary sealant area throughout the roll filling process. The laminating rollers are configured as pressure rollers that apply a constant pressure on the substrate during the lamination process, or are configured as gap-set rollers in which the top laminating roller is spaced a set distance from the bottom laminating roller and allows the top substrate and the bottom substrate to match without compressing the controlled gap and spacers between the top substrate and the bottom substrate. The matched substrates are cured after lamination by UV radiation, heat, or a combination of UV curing and thermal curing. The cured substrates are subsequently cut into sheets from the roll for additional processing.

Claims

1. A method of producing a flexible element unit for an optical device, the flexible element unit being surrounded by a boundary seal and filled with an electro-optical material, the flexible element unit having a first substrate and a second substrate separated by a controlled distance, the method comprising: providing two continuous sheets of flexible plastic material to form said first substrate and said second substrate, depositing a border sealant on at least one of the first substrate and the second substrate to define the border seal, wherein the border seal is a continuous border seal, depositing the electro-optic material on the at least one substrate, the electro-optic material being in a non-discrete, non-encapsulated, non-polymeric state and containing less than 1% polymerizable material, wherein the electro-optic material is generally non-polymerizable; and matching the first substrate and the second substrate when roll-filling the flexible element with the electro-optic material using one or more lamination rollers such that the electro-optic material completely fills the controlled distance between the first substrate and the second substrate, wherein the controlled distance of the flexible element units is maintained by non-patterned spacers, Wherein, the optical device is a transparent device; The electro-optical material can be changed by applying an electric current or an electric field; The non-patterned spacers are spherical or have an aspect ratio less than 10 / 1, and The number of the spacers is greater than 80 per square millimeter.

2. The method of claim 1, wherein the method further comprises: The border sealant and the electro-optic material are applied to the at least one substrate before the roll-to-roll filling step, and the border sealant is cured after the roll-to-roll filling step to form the border seal.

3. The method of claim 2, wherein the electro-optical material is deposited on an area outside the perimeter of the boundary sealant, on an area inside the perimeter of the boundary sealant, or on one or more areas inside and outside the perimeter of the boundary sealant.

4. The method of claim 2, wherein a ratio of the viscosity of the border sealant to the viscosity of the electro-optic material is greater than 10.

5. The method of claim 1, wherein the method comprises applying a plurality of boundary sealants to the first substrate, or the second substrate, or both substrates.

6. The method of claim 2, wherein the method includes applying a plurality of boundary sealants to the first substrate, the second substrate, or both substrates.

7. The method according to any one of claims 1 to 6, wherein the method further comprises cutting the flexible element units from the two continuous sheets of flexible plastic material using a mechanical punch cutter, or a laser cutter, or a combination thereof.

8. The method of any one of claims 1-6, further comprising, after the roll filling step, cutting or welding a shape to form the boundary seal and to separate the flexible element unit from the two continuous flexible plastic sheets.

9. The method of any one of claims 1-6, wherein the method further comprises depositing the non-patterned spacer on the first substrate, on the second substrate, within the electro-optical material, or on a combination thereof.

10. The method of any one of claims 1-6, wherein the non-patterned spacer is applied on at least one of the first substrate and the second substrate.

11. The method of any one of claims 1-6, wherein the method further comprises applying an alignment layer on the first substrate, the second substrate, or both.

12. The method of claim 11, wherein the alignment layer comprises the non-patterned spacers.

13. The method of any one of claims 1 to 6, wherein the method further comprises adding partition walls to one or both substrates.

14. The method of claim 11, wherein the alignment layer is deposited by printing the alignment layer on an area selected from the group consisting of: a selected active area and an entire active area of ​​one or both of the first substrate and the second substrate.

15. The method of any one of claims 1 to 6, wherein the flexible element unit is an optical device having a haze value of less than 8%.

16. The method of any one of claims 1 to 6, wherein the method is performed without the use of a vacuum.

17. The method of any one of claims 1 to 6, wherein the non-patterned spacers are spherical and have a diameter of 3-100 μm.

18. The method of any one of claims 1 to 6, wherein the electro-optic material is a guest-host dichroic dye-liquid crystal mixture.

19. The method according to any one of claims 1 to 6, wherein the flexible element unit has a length greater than 10 cm or a length greater than 30 cm. 2 area.

20. The method according to any one of claims 1 to 6, wherein the flexible element unit has a width greater than 50 cm 2 area.

21. The method of claim 2, wherein the border sealant is cured using UV light, pressure, chemical interaction, moisture, or a combination thereof.

22. The method of any one of claims 1 to 6, wherein: The non-patterned spacers are arranged in a non-diffractive pattern.

23. A flexible element unit manufactured by the method of any one of claims 1 to 22 without the use of a vacuum.

24. A non-diffractive flexible element unit for an optical device, the flexible element unit being surrounded by a boundary seal, the flexible element unit comprising: a first substrate and a second substrate separated by a controlled distance; An electro-optic material that is in a non-discrete, non-encapsulated, non-polymeric state and contains less than 1% polymerizable material; as well as non-patterned spacers; Wherein, the optical device is a transparent device, The first substrate and the second substrate include flexible plastic, The electro-optic material and the non-patterned spacer are arranged between the first substrate and the second substrate, The electro-optic material completely fills a controlled distance between the first substrate and the second substrate, The controlled distance is maintained by the non-patterned spacer, The electro-optical material can be changed by applying an electric current or an electric field, The non-patterned spacers have an aspect ratio less than 10 / 1, and the number of the spacers is greater than 80 per square millimeter.

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