Liquid crystal window including a bistable liquid crystal

Abstract

A liquid crystal device comprises a liquid crystal cell. The liquid crystal cell comprises first and second glass substrates; first and second polarizers having first and second transmission axes, respectively; first and second electrodes; first and second orientation layers disposed between the first and second electrodes; and a liquid crystal layer disposed between the first and second orientation layers. The liquid crystal layer comprises a nematic liquid crystal. At zero applied voltage to the first and second electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state. The first stable state is switchable to the second stable state by application of a first stimulus. The second stable state is switchable to the first stable state by application of a second stimulus. The liquid crystal cell has certain visible light transmittance and haze values.

Description

LIQUID CRYSTAL WINDOW INCLUDING A BISTABLE LIQUID CRYSTALCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application No. 63 / 537,352 filed September 8, 2023, the content of which is incorporated herein by reference in its entirety.FIELD

[0002] The disclosure relates generally to a liquid crystal device comprising a multi-stable liquid crystal, and more particularly to a liquid crystal window comprising a bistable nematic liquid crystal with first and second polarizers, as well as methods of making and methods of operating.BACKGROUND

[0003] Liquid crystal devices are used in various architectural, transportation, and commercial applications, such as windows, displays, doors, space partitions, and skylights for buildings and automobiles. However, many liquid crystal devices require power by way of an applied voltage to maintain a “light’ or “dark” state, and / or do not have both a “light” and a “dark” state at zero applied voltage. There is a need in the art, therefore, for improved liquid crystal devices, including in applications such as windows and displays.SUMMARY

[0004] The disclosure relates, in various aspects, to liquid crystal devices, comprising: a liquid crystal cell, comprising: first and second glass substrates; first and second polarizers having first and second transmission axes, respectively; first and second electrodes; first and second orientation layers disposed between the first and second electrodes; and a liquid crystal layer disposed between the first and second orientation layers, the liquid crystal layer in electrical communication with the first and second electrodes; wherein: the first and second polarizers are stable at a temperature of at least 100 °C for at least one hour; the liquid crystal layer comprises a nematic liquid crystal;at zero applied voltage to the first and second electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state by way of alignment imparted by at least one of the first and second orientation layers; the first stable state is switchable to the second stable state by application of a first stimulus, and the second stable state is switchable to the first stable state by application of a second stimulus; the liquid crystal cell has visible light transmittance in the first stable state that is different by at least 20% from visible light transmittance in the second stable state; and the liquid crystal cell has haze of less than 5% in both the first stable state and the second stable state.

[0005] The disclosure relates, in various aspects, to liquid crystal devices, comprising: a liquid crystal cell, comprising: first and second glass substrates; first and second polarizers having first and second transmission axes, respectively; first and second electrodes; first and second orientation layers disposed between the first and second electrodes; and a liquid crystal layer disposed between the first and second orientation layers, the liquid crystal layer in electrical communication with the first and second electrodes; wherein: the first and second polarizers are disposed between the first and second glass substrates; the liquid crystal layer comprises a nematic liquid crystal; at zero applied voltage to the first and second electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state by way of alignment imparted by at least one of the first and second orientation layers; the first stable state is switchable to the second stable state by application of a first stimulus, and the second stable state is switchable to the first stable state by application of a second stimulus;the liquid crystal cell has visible light transmittance in the first stable state that is different by at least 20% from visible light transmittance in the second stable state; and the liquid crystal cell has haze of less than 5% in both the first stable state and the second stable state.

[0006] The disclosure relates, in various aspects, to liquid crystal devices, comprising: a liquid crystal cell, comprising: first and second glass substrates; first and second polarizers having first and second transmission axes, respectively; first and second electrodes; first and second orientation layers disposed between the first and second electrodes; and a liquid crystal layer disposed between the first and second orientation layers, the liquid crystal layer in electrical communication with the first and second electrodes; wherein: the liquid crystal device is or comprises a liquid crystal window, and the first and second electrode extend continuously over at least 50% of the area of the liquid crystal window; the liquid crystal layer comprises a nematic liquid crystal; at zero applied voltage to the first and second electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state by way of alignment imparted by at least one of the first and second orientation layers; the first stable state is switchable to the second stable state by application of a first stimulus, and the second stable state is switchable to the first stable state by application of a second stimulus; the liquid crystal cell has visible light transmittance in the first stable state that is different by at least 20% from visible light transmittance in the second stable state; and the liquid crystal cell has haze of less than 5% in both the first stable state and the second stable state.

[0007] The disclosure relates, in various aspects, to liquid crystal devices comprising a liquid crystal window, the liquid crystal windows comprising: a liquid crystal cell, comprising:first and second polarizers having first and second transmission axes, respectively; first and second electrodes; first and second orientation layers disposed between the first and second electrodes, the liquid crystal layer in electrical communication with the first and second electrodes; a liquid crystal layer disposed between the first and second orientation layers; and first and second glass substrates, wherein the first and second electrodes and the first and second polarizers are disposed between the first and second glass substrates; third and fourth glass substrates; wherein the first and second glass substrates are disposed between the third and fourth glass substrates, the first and third glass substrates being proximal to one another and the second and fourth glass substrates being proximal to one another; a first insulating gas disposed between the first and third glass substrates; a second insulating gas disposed between the second and fourth glass substrates; and a frame attached to minor surfaces of the first, second, third, and fourth glass substrates; wherein: the liquid crystal layer comprises a nematic liquid crystal; at zero applied voltage to the first and second electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state by way of alignment imparted by at least one of the first and second orientation layers; the first stable state is switchable to the second stable state by application of a first stimulus, and the second stable state is switchable to the first stable state by application of a second stimulus; the liquid crystal cell has visible light transmittance in the first stable state that is different by at least 20% from visible light transmittance in the second stable state; and the liquid crystal cell has haze of less than 5% in both the first stable state and the second stable state.

[0008] The disclosure relates, in various aspects, to liquid crystal devices comprising an insulated glass unit, the insulated glass unit comprising: a liquid crystal cell, comprising: first and second polarizers having first and second transmission axes, respectively;first and second electrodes; first and second orientation layers disposed between the first and second electrodes, the liquid crystal layer in electrical communication with the first and second electrodes; a liquid crystal layer disposed between the first and second orientation layers; and first and second glass substrates, wherein the first and second electrodes and the first and second polarizers are disposed between the first and second glass substrates; a third glass substrate; and a first insulating gas disposed between the first and third glass substrates; wherein: the liquid crystal layer comprises a nematic liquid crystal; at zero applied voltage to the first and second electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state by way of alignment imparted by at least one of the first and second orientation layers; the first stable state is switchable to the second stable state by application of a first stimulus, and the second stable state is switchable to the first stable state by application of a second stimulus; the liquid crystal cell has visible light transmittance in the first stable state that is different by at least 20% from visible light transmittance in the second stable state; and the liquid crystal cell has haze of less than 5% in both the first stable state and the second stable state.

[0009] The disclosure relates, in various aspects, to methods for switching the liquid crystal devices disclosed herein.

[0010] The disclosure relates, in various aspects, to methods of making the liquid crystal devices disclosed herein.

[0011] Additional features and advantages of the disclosure will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the aspects as described herein, including the detailed description which follows, the claims, as well as the appended drawings.

[0012] It is to be understood that both the foregoing general description and the following detailed description are merely exemplary and are intended to provide an overview or framework for understanding the nature and character of the disclosure and claims. The accompanying drawings are included to provide a further understanding of the disclosure and are incorporated into and constitute a part of this specification. The drawings illustrate various aspects of the disclosure and together withthe description serve to explain the principles and operations of the various aspects. It is to be understood that various features of the disclosure disclosed in this specification and in the drawings can be used in any and all combinations.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The following detailed description can be further understood when read in conjunction with the following drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. It is to be understood that the figures are not drawn to scale and the size of each depicted component or the relative size of one component to another is not intended to be limiting.

[0014] FIGs. 1A-1B depict cross-sectional views of liquid crystal devices according to various aspects of the disclosure.

[0015] FIGs. 2A-2C depict cross-sectional views of liquid crystal devices according to various aspects of the disclosure.

[0016] FIG. 3 depicts a cross-sectional view of a liquid crystal device according to various aspects of the disclosure.

[0017] FIGs. 4A-4B depict cross-sectional views of liquid crystal devices according to various aspects of the disclosure.

[0018] FIGs. 5A-5B depict schematics of liquid crystal devices depicting switching liquid crystal layers from a first stable state to a second stable state, according to various aspects of the disclosure.

[0019] FIG. 6 depicts a schematic of a liquid crystal device depicting switching a liquid crystal layer from a first stable state to a second stable state, according to various aspects of the disclosure.

[0020] FIGs. 7A-7C depict schematics of liquid crystal devices depicting switching liquid crystal layers from a first stable state to a second stable state, according to various aspects of the disclosure.

[0021] FIG. 8A depicts a schematic cut-away side view of an insulated glass unit incorporating a liquid crystal cell, according to various aspects of the disclosure.

[0022] FIG. 8B depicts a schematic cut-away side view of a liquid crystal window having a triple pane IGU with a liquid crystal cell as the center pane, according to various aspects of the disclosure.DETAILED DESCRIPTION

[0023] In the following description, whenever a group is described as comprising at least one of a group of elements and combinations thereof, it is understood that the group may comprise, consist essentially of, or consist of any number of those elements recited, either individually or in combination with each other. Similarly, whenever a group is described as consisting of at least one of a group of elements or combinations thereof, it is understood that the group may consist of any number of those elements recited, either individually or in combination with each other.

[0024] Where a range of numerical values is recited herein, comprising upper and lower values, unless otherwise stated in specific circumstances, the range is intended to include the endpoints thereof, and all integers and fractions within the range. Further, when an amount, concentration, or other value or parameter is given as a range, one or more ranges, or a list of upper values and lower values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or value and any lower range limit or value, regardless of whether such pairs are separately disclosed.

[0025] If the term “about” is used in describing a value or an end-point of a range, the disclosure should be understood to include the specific value or end-point referred to. As used herein, the term “about” means that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and / or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art. It is noted that the terms “substantially” may be utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. These terms are also utilized herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue. Thus, for example, a glass that is “free” or “essentially free” of AI2O3 (or any other component) is one in which AI2O3 (or any other component) is not actively added or batched into the glass, but may be present in very small amounts as a contaminant (e.g., 500, 400, 300, 200, or 100 ppm or less or).

[0026] As used herein, the term “in electrical communication” with respect to the liquid crystal layer and first and second electrodes means that the liquid crystal layer is susceptible to changing orientation when a stimulus such as a voltage pulse is applied across the first and second electrodes, for example, by way of the liquid crystals being impacted by an electrical phenomenon including but not limited to an electric field.

[0027] As used herein, “stable state” in reference to a liquid crystal means that the liquid crystal is able to maintain the state without continuous application of voltage for a certain time period, typically at least 1 hour. However, other time periods are also possible, including at least 2 hours, at least 3 hours, at least 4 hours, at least 6 hours, at least 8 hours, at least 10 hours, at least 12 hours, at least 16 hours, at least 20 hours, or at least 24 hours, or more, including all ranges and subranges that can be made from any two of the foregoing numbers. Stability is in reference to the liquid crystal layer as a whole, including any other materials that may be present in addition to the liquid crystals, such as chiral dopants, polymers, and so forth, and other layers such as one or more orientation layers.

[0028] As used herein, “bistable state” in reference to a liquid crystal means that there are two “stable” states of the liquid crystal.

[0029] As used herein, “stable” in reference to polarizers means that a polarizer is able to withstand the indicated condition (e.g., a given temperature for a given period of time, such as a temperature of at least 100 °C for at least one hour, or any other temperature / time combination disclosed elsewhere herein) while substantially maintaining its original light polarization properties and without substantially changing color (which would affect its desired light transmittance / absorbance properties).

[0030] As used herein, “ultraviolet light” or “UV light” means light having a wavelength of 10 nm to <380 nm.

[0031] As used herein, “visible light” means light having a wavelength in the range of 380 to <750 nm.

[0032] As used herein, “infrared light” or “IR light” means light having a wavelength of 750 nm to 1 mm.

[0033] As used herein, “haze” is defined as the percent of transmitted light that is scattered so that its direction deviates more than 2.5 degrees from the direction of the incident beam, and “luminous transmittance” is defined as the percent of transmitted light, per American Society for Testing and Materials (ASTM) DI 003 “Standard Test Method for Haze and Luminous Transmittance of Transparent Plastics.” The terms “transmittance,” “luminous transmittance,” “visible light transmittance,” and similarly worded terms are used interchangeably herein and are intended to have the same meaning, unless clearly contracted by context (e.g., transmittance relating specifically to UV and / or IR). Haze and transmittance can be measured by various haze meters such as BYK-Gardner’s Haze-Gard. As used herein, the haze and transmittance of a liquid crystal cell refers to the haze and transmittance as measured through the first and second electrodes, first and second orientation layers (if both are present), a liquid crystal layer, first and second substrates (if one or both are present), and one or more polarizers (if present). Generally, transmittance as disclosed herein does not include transmittance through interlayers, insulating gases, third and fourth substrates, UV / IR layers, and so forth.

[0034] As used herein, “switchable” in reference to stable states of a liquid crystal means that the liquid crystal in a given system (i.e., considering all other materials and structures present) is capable of being changed from one stable state to another stable state by application of an appropriate stimulus, such as one or more voltage pulses.

[0035] As used herein, the terms “light” and “dark” states are generally used in reference to light transmittance, in which light transmittance in the “dark” state is less than light transmittance in the “light” state as viewed perpendicular to the plane of the liquid crystal cell. In a multi-stable state liquid crystal system, such as a bistable liquid crystal system, the “dark” state corresponds to one stable state of the liquid crystals and the “light” state corresponds to another stable state of the liquid crystals (e.g., stable states at zero applied voltage).

[0036] As used herein, the term “optically transparent” and similar such terms mean a transmission of greater than 80% of light in the visible region of the spectrum (-400-700 nm). However, a heightened level of optical transparency can also be employed herein, such as a transmission of at least 85%, at least 90%, at least 95%, at least 99%, or 100% of light in the visible region of the spectrum (-400-700 nm). Any such optical transparency values generally apply to a liquid crystal cell, but can also be applied to any individual or combination structure disclosed herein, such as a substrate, electrode, liquid crystal layer, and so forth.

[0037] Liquid crystal devices can serve as “smart” or tintable windows or displays for many commercial applications. It is desirable for smart liquid crystal windows or displays to provide high contrast ratio between the on and off states. Liquid crystals having multiple stable states can be used in smart windows or displays to provide at least two stable states in the absence of applied voltage. In some aspects, a first stable state is more transparent to visible light (a “light” or “clear” state) than a second stable state (a “dark,” tinted, or opaque state). In some aspects, the liquid crystal in the window or display can be switched from the first stable state to the second stable state and vice versa via a stimulus, such as one or more voltage pulses. In some aspects, additional stable states are possible with the same or different transparency to light as the first and / or second stable states, allowing for the possibility of different visible light transparencies.

[0038] Existing windows fail to possess desirable properties. For example, existing windows with bistable liquid crystals do not have sufficiently low transparency in one of the two stable states so as to block a desirable amount of visible light from transmitting through the window. In addition, such existing windows typically require a high switching voltage, such as in the range of 60-120 V. Moreover, existing transmissive mode displays employ a pair of conventional iodine polarizers having a high extinction ratio to achieve satisfactory contrast ratio; however, such displays cannot be used as switchable windows because the conventional iodine polarizers cannot endure a downstream high temperature lamination process. Furthermore, the boundary area between small pixels in a display application cannot be switched, compromising the high transmittance required in the light state and low transmittance required in a dark state.

[0039] It would be advantageous for liquid crystal windows to require no power to maintain two or more stable states, a low voltage (e.g., less than 60 V) to switch between stable states, “dark” and “light” states for at least two of the stable states, switchability, minimal or no boundary areas between pixels (e.g., one single pixel without boundaries, or a few pixels with minimal boundaries). These goals, as well as others, are achieved in one or more aspects according to the present disclosure.Liquid Crystal Cell

[0040] The disclosure relates, in various aspects, to liquid crystal devices, comprising: a liquid crystal cell, comprising: first and second glass substrates;first and second polarizers having first and second transmission axes, respectively; first and second electrodes; first and second orientation layers disposed between the first and second electrodes; and a liquid crystal layer disposed between the first and second orientation layers, the liquid crystal layer in electrical communication with the first and second electrodes; wherein: the first and second polarizers are stable at a temperature of at least 100 °C for at least one hour; the liquid crystal layer comprises a nematic liquid crystal; at zero applied voltage to the first and second electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state by way of alignment imparted by at least one of the first and second orientation layers; the first stable state is switchable to the second stable state by application of a first stimulus, and the second stable state is switchable to the first stable state by application of a second stimulus; the liquid crystal cell has visible light transmittance in the first stable state that is different by at least 20% from visible light transmittance in the second stable state; and the liquid crystal cell has haze of less than 5% in both the first stable state and the second stable state.

[0041] The disclosure relates, in various aspects, to liquid crystal devices, comprising: a liquid crystal cell, comprising: first and second glass substrates; first and second polarizers having first and second transmission axes, respectively; first and second electrodes; first and second orientation layers disposed between the first and second electrodes; and a liquid crystal layer disposed between the first and second orientation layers, the liquid crystal layer in electrical communication with the first and second electrodes; wherein:the first and second polarizers are disposed between the first and second glass substrates; the liquid crystal layer comprises a nematic liquid crystal; at zero applied voltage to the first and second electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state by way of alignment imparted by at least one of the first and second orientation layers; the first stable state is switchable to the second stable state by application of a first stimulus, and the second stable state is switchable to the first stable state by application of a second stimulus; the liquid crystal cell has visible light transmittance in the first stable state that is different by at least 20% from visible light transmittance in the second stable state; and the liquid crystal cell has haze of less than 5% in both the first stable state and the second stable state.

[0042] The disclosure relates, in various aspects, to liquid crystal devices, comprising: a liquid crystal cell, comprising: first and second glass substrates; first and second polarizers having first and second transmission axes, respectively; first and second electrodes; first and second orientation layers disposed between the first and second electrodes; and a liquid crystal layer disposed between the first and second orientation layers, the liquid crystal layer in electrical communication with the first and second electrodes; wherein: the liquid crystal device is or comprises a liquid crystal window, and the first and second electrode extend continuously over at least 50% of the area of the liquid crystal window; the liquid crystal layer comprises a nematic liquid crystal; at zero applied voltage to the first and second electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state by way of alignment imparted by at least one of the first and second orientation layers;the first stable state is switchable to the second stable state by application of a first stimulus, and the second stable state is switchable to the first stable state by application of a second stimulus; the liquid crystal cell has visible light transmittance in the first stable state that is different by at least 20% from visible light transmittance in the second stable state; and the liquid crystal cell has haze of less than 5% in both the first stable state and the second stable state.

[0043] The disclosure relates, in various aspects, to liquid crystal devices comprising a liquid crystal window, the liquid crystal windows comprising: a liquid crystal cell, comprising: first and second polarizers having first and second transmission axes, respectively; first and second electrodes; first and second orientation layers disposed between the first and second electrodes, the liquid crystal layer in electrical communication with the first and second electrodes; a liquid crystal layer disposed between the first and second orientation layers; and first and second glass substrates, wherein the first and second electrodes and the first and second polarizers are disposed between the first and second glass substrates; third and fourth glass substrates; wherein the first and second glass substrates are disposed between the third and fourth glass substrates, the first and third glass substrates being proximal to one another and the second and fourth glass substrates being proximal to one another; a first insulating gas disposed between the first and third glass substrates; a second insulating gas disposed between the second and fourth glass substrates; and a frame attached to minor surfaces of the first, second, third, and fourth glass substrates; wherein: the liquid crystal layer comprises a nematic liquid crystal; at zero applied voltage to the first and second electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state by way of alignment imparted by at least one of the first and second orientation layers;the first stable state is switchable to the second stable state by application of a first stimulus, and the second stable state is switchable to the first stable state by application of a second stimulus; the liquid crystal cell has visible light transmittance in the first stable state that is different by at least 20% from visible light transmittance in the second stable state; and the liquid crystal cell has haze of less than 5% in both the first stable state and the second stable state.

[0044] The disclosure relates, in various aspects, to liquid crystal devices comprising an insulated glass unit, the insulated glass unit comprising: a liquid crystal cell, comprising: first and second polarizers having first and second transmission axes, respectively; first and second electrodes; first and second orientation layers disposed between the first and second electrodes, the liquid crystal layer in electrical communication with the first and second electrodes; a liquid crystal layer disposed between the first and second orientation layers; and first and second glass substrates, wherein the first and second electrodes and the first and second polarizers are disposed between the first and second glass substrates; a third glass substrate; and a first insulating gas disposed between the first and third glass substrates; wherein: the liquid crystal layer comprises a nematic liquid crystal; at zero applied voltage to the first and second electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state by way of alignment imparted by at least one of the first and second orientation layers; the first stable state is switchable to the second stable state by application of a first stimulus, and the second stable state is switchable to the first stable state by application of a second stimulus; the liquid crystal cell has visible light transmittance in the first stable state that is different by at least 20% from visible light transmittance in the second stable state; and the liquid crystal cell has haze of less than 5% in both the first stable state and the second stable state.

[0045] In some aspects, any liquid crystal cell herein can have any suitable visible light transmittance. In some aspects, the liquid crystal layer has multiple stable states, such as a first stable state and a second stable state. In some aspects, the visible light transmittance in one stable state (e.g., first stable state) is different from a visible light transmittance in any other stable state (e.g., second stable state) by at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, or at least 70%. Alternatively, or additionally, the visible light transmittance in one stable state (e.g., first stable state) is different from a visible light transmittance in any other stable state (e.g., second stable state) by less than 70%, less than 65%, less than 60%, less than 55%, less than 50%, less than 45%, less than 40%, less than 35%, less than 30%, or less than 25%. Any of the two foregoing open-ended ranges can be combined in any manner to describe a closed range for visible light transmittance, such as 20-70%, 20-65%, 20-60%, 20-55%, 20- 50%, 20-45%, 20-40%, 20-35%, 20-30%, 20-25%, 25-70%, 25-65%, 25-60%, 25-55%, 25-50%, 25- 45%, 25-40%, 25-35%, 25-30%, 30-70%, 30-65%, 30-60%, 30-55%, 30-50%, 30-45%, 30-40%, 30- 35%, 35-70%, 35-65%, 35-60%, 35-55%, 35-50%, 35-45%, 35-40%, 40-70%, 40-65%, 40-60%, 40- 55%, 40-50%, 40-45%, 45-70%, 45-65%, 45-60%, 45-55%, 45-50%, 50-70%, 50-65%, 50-60%, 50- 55%, 55-70%, 55-65%, 55-60%, 60-70%, 60-65%, or 65-70%. Differences in visible light transmittance between various stable states of the liquid crystal are calculated by measuring the visible light transmittance (e.g., X%) in one stable state, measuring the visible light transmittance in another stable state (e.g., Y%), and taking the absolute value of the result of X% - Y%.

[0046] In some aspects, the liquid crystal cell has visible light transmittance of at least 45% in one stable state (e.g., first or second stable states), and the liquid crystal cell has visible light transmittance of less than 45% in another stable state (e.g., the other of the first or second stable states). In some aspects, one stable state (e.g., first or second stable states) has a visible light transmittance of at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, or at least 85%, or alternatively or additionally less than 85%, less than 80%, less than 75%, less than 70%, less than 65%, less than 60%, less than 55%, or less than 50%. Any of the two foregoing open-ended ranges can be combined in any manner to describe a closed range for visible light transmittance in one stable state (e.g., a first or second stable state), such as 45-85%, 45- 80%, 45-75%, 45-70%, 45-65%, 45-60%, 45-55%, 45-50%, 50-85%, 50-80%, 50-75%, 50-70%, 50- 65%, 50-60%, 50-55%, 55-85%, 55-80%, 55-75%, 55-70%, 55-65%, 55-60%, 60-85%, 60-80%, 60- 75%, 60-70%, 60-65%, 65-85%, 65-80%, 65-75%, 65-70%, 70-85%, 70-80%, 70-75%, 75-85%, 75- 80%, or 80-85%. In some aspects, the other stable state (e.g., first or second stable states) has a visible light transmittance of less than 45%, less than 40%, less than 35%, less than 30%, less than 25%, less than 20%, less than 15%, less than 10%, less than 5%, or less than 1%, or alternatively or additionally at least 1%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, or at least 40%. Any of the two foregoing open-ended ranges can be combined in any manner todescribe a closed range for visible light transmittance in the other stable state (e.g., a first or second stable state), such as 1-45%, 1-40%, 1-35%, 1-30%, 1-25%, 1-20%, 1-15%, 1-10%, 1-5%, 5-45%, 5-40%, 5-35%, 5-30%, 5-25%, 5-20%, 5-15%, 5-10%, 10-45%, 10-40%, 10-35%, 10-30%, 10-25%, 10-20%, 10-15%, 15-45%, 15-40%, 15-35%, 15-30%, 15-25%, 15-20%, 20-45%, 20-40%, 20-35%, 20-30%, 20-25%, 25-45%, 25-40%, 25-35%, 25-30%, 30-45%, 30-40%, 30-35%, 35-45%, 35-40%, or40-45%. In some aspects, the liquid crystal cell has visible light transmittance of at least 45% in the first stable state or the second stable state; and the liquid crystal cell has visible light transmittance of less than 45% in the other of the first stable state or the second stable state.

[0047] Any visible light transmittance difference disclosed herein (relative to different stable states) can be paired with any actual visible light transmittance disclosed herein. For example, one stable state can have a visible light transmittance of less than 15% and the visible light transmittance difference from another stable state can be at least 35% (making the visible light transmittance of the other stable state at least 50%). Any other combination of such features can be made and a similar calculation performed.

[0048] In some aspects, any liquid crystal cell herein can have any suitable haze. In some aspects, a liquid crystal cell has a haze of less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4.5%, less than 4%, less than 3.5%, less than 3%, less than 2.5%, less than 2%, less than 1.5%, less than 1%, less than 0.5%, or less than 0.1%, or alternatively or additionally at least 0.1%, at least 0.5%, at least 1%, at least 1.5%, at least 2%, at least 2.5%, at least3%, at least 3.5%, at least 4%, at least 4.5%, at least 5%, at least 6%, at least 7%, at least 8%, or at least 9%. Any of the two foregoing open-ended ranges can be combined in any manner to describe a closed range for haze of the liquid crystal cell, such as 0.1-10%, 0.1-9%, 0.1-8%, 0.1-7%, 0.1-6%,0.1-5%, 0. 1-4.5%, 0.1-4%, 0.1-3.5%, 0.1-3%, 0.1-2.5%, 0.1-2%, 0.1-1.5%, 0.1-1%, 0.1-0.5%, 0.5-10%, 0.5-9%, 0.5-8%, 0.5-7%, 0.5-6%, 0.5-5%, 0.5-4.5%, 0.5-4%, 0.5-3.5%, 0.5-3%, 0.5-2.5%, 0.5-2%, 0.5-1.5%, 0.5-1%, 1-10%, 1-9%, 1-8%, 1-7%, 1-6%, 1-5%, 1-4.5%, 1-4%, 1-3.5%, 1-3%, 1-2.5%, 1-2%, 1-1.5%, 1.5-10%, 1.5-9%, 1.5-8%, 1.5-7%, 1.5-6%, 1.5-5%, 1.5-4.5%, 1.5-4%, 1.5-3.5%, 1.5-3%, 1.5-2.5%, 1.5-2%, 2-10%, 2-9%, 2-8%, 2-7%, 2-6%, 2-5%, 2-4.5%, 2-4%, 2-3.5%, 2-3%, 2-2.5%, 2.5-10%, 2.5-9%, 2.5-8%, 2.5-7%, 2.5-6%, 2.5-5%, 2.5-4.5%, 2.5-4%, 2.5-3.5%, 2.5-3%, 3-10%, 3-9%, 3-8%, 3-7%, 3-6%, 3-5%, 3-4.5%, 3-4%, 3-3.5%, 3.5-10%, 3.5-9%, 3.5-8%, 3.5-7%, 3.5-6%, 3.5-5%, 3.5-4.5%, 3.5-4%, 4-10%, 4-9%, 4-8%, 4-7%, 4-6%, 4-5%, 4-4.5%, 4.5-10%,4.5-9%, 4.5-8%, 4.5-7%, 4.5-6%, 4.5-5%, 5-10%, 5-9%, 5-8%, 5-7%, 5-6%, 6-10%, 6-9%, 6-8%, 6-7%, 7-10%, 7-9%, 7-8%, 8-10%, 8-9%, or 9-10%. Generally, the haze is in reference to the liquid crystal cell when the liquid crystal is in all possible stable states, such as first and second stable states. However, in some aspects, the haze can be in reference to a specific stable state, and any haze value disclosed herein can be applied to that specific stable state (such as a first stable state, or a second stable state, or both first and second stables states.Materials and ComponentsElectrode

[0049] In some aspects, any liquid crystal device or cell disclosed herein includes at least one electrode. In some aspects, the liquid crystal device or cell comprises any electrode known in the art that is suitable for liquid crystal devices or cells, for example liquid crystal devices or cells that are used in window applications. For example, in some aspects the liquid crystal device or cell comprises first and second electrodes. In some aspects, additional electrodes may be present depending on liquid crystal device, cell, or window configuration. In some aspects, the characteristics and properties of each electrode can be independently selected and can be the same or different from other electrodes in the liquid crystal device, cell, or window. In some aspects, the first and / or second electrodes (and / or optional additional electrodes) comprise interdigitated electrodes.

[0050] In some aspects, each electrode (e.g., first and / or second electrodes) independently comprises one or more transparent conductive oxides (TCOs), such as indium tin oxide (ITO), indium zinc oxide (IZO), gallium zinc oxide (GZO), aluminum zinc oxide (AZO), or other like materials, or any combination thereof. Alternatively or additionally, in some aspects each such electrode independently comprises other transparent materials, such as a conductive mesh, e.g., comprising metals such as silver nanowires or other nanomaterials such as graphene or carbon nanotubes, or any combination thereof. Alternatively or additionally, in some aspects, each such electrode independently comprises one or more printable conductive ink layers, such as ActiveGrid™ available from C3Nano Inc. In some aspects, each electrode independently has a sheet resistance ranging from (Ohms per square) 10 to 1000, 50 to 900, 100 to 800, 200 to 700, 300 to 600, or 400 to 500, or any range that can be made from any two of the foregoing numbers.

[0051] In some aspects, each electrode is fabricated using any technique known in the art, such as vacuum sputtering, film lamination, printing techniques, or any combination thereof. In some aspects, each electrode can be deposited on one or more substrate surfaces to form a layer of material that may or may not comprise a pattern. In some aspects, the thickness of each electrode can, for example, independently range from 1 nm to 1000 nm, such as from 5 nm to 500 nm, from 10 nm to 300 nm, from 20 nm to 200 nm, from 30 nm to 150 nm, or from 50 nm to 100 nm, or any range that can be made from any two of the foregoing numbers.

[0052] In some aspects, each electrode can have any suitable dimensions. In some aspects, an electrode (e.g., first and second electrodes) extends continuously over at least 20% (e.g., at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 99%, or at least 100%) of the area of the liquid crystal window. As used herein, the “area” of a liquid crystal window is the area that light is intended to be transmitted through such that the liquid crystal device functions as a window. In this regard, the liquid crystal devices and windows disclosed here generally are not comprised of small “pixels,” which may result boundaries between each pixel thatare unable to have both dark and light states, negatively impacting its use as a switchable window. Rather, in some aspects, the liquid crystal devices and windows herein comprise larger cell dimensions that help facilitate such devices and windows to be used as switchable windows. In some aspects, each electrode (and / or each polarizer, substrate, orientation layer, or any combination thereof) extends continuously with a plane (e.g., generally the plane is co-planar with the first and second electrodes, first and second substrates, first and second polarizers, first and second orientation layers, and so forth) over first and second dimensions. In some aspects, at least one of the first and second dimensions (mm) is at least 10, at least 20, at least 30, at least 40, at least 50, at least 60, at least 70, at least 80, at least 90, at least 100, at least 110, at least 120, at least 130, at least 140, at least 150, at least 160, at least 170, at least 180, at least 190, at least 200, at least 220, at least 240, at least 260, at least 280, at least 300, at least 350, at least 400, at least 450, or at least 500; alternatively, or additionally, at least one of the first and second dimensions (mm) is less than 550, less than 500, less than 450, less than 400, less than 350, less than 300, less than 280, less than 260, less than 240, less than 220, less than 200, less than 190, less than 180, less than 170, less than 160, less than 150, less than 140, less than 130, less than 120, less than 110, less than 100, less than 90, less than 80, less than 70, less than 60, less than 50, less than 40, less than 30, or less than 20. Any two of the aforementioned open-ended ranges can be combined to form a close-ended range, such as 10-150 mm, 50-120 mm, and so forth. In some aspects, both the first and second dimensions have any of the aforementioned values. In some aspects, each of the first and second dimensions is at least 50 mm. In some aspects, each of the first and second dimensions is at least 100 mm. In some aspects, the size of the first and second dimensions (e.g., at least 10 mm, etc.) is relatively larger than the size of dimensions of other pixels known in the art, which typically are smaller than 1 mm, or even smaller than 0.1 mm.

[0053] In some aspects, the dimensions herein for the first and second dimensions of the first and second electrodes corresponds to a pixel size. In some aspects, the liquid crystal devices or windows herein contain one or more pixels. In some aspects, a liquid crystal cell corresponds to one pixel (e.g., each liquid crystal cell in a liquid crystal device is one pixel). In some aspects, the liquid crystal devices or windows herein contain 1-100 pixels, or 1-50 pixels, such as 1-45, 1-40, 1-35, 1-30, 1-25, 1-20, 1-15, 1-10, 1-5, 5-50, 5-45, 5-40, 5-35, 5-30, 5-25, 5-20, 5-15, 5-10, 10-50, 10-45, 10-40, 10-35, 10-30, 10-25, 10-20, 10-15, 15-50, 15-45, 15-40, 15-35, 15-30, 15-25, 15-20, 20-50, 20-45, 20-40, 20- 35, 20-30, 20-25, 25-50, 25-45, 25-40, 25-35, 25-30, 30-50, 30-45, 30-40, 30-35, 35-50, 35-45, 35-40, 40-50, 40-45, or 45-50 pixels. In some aspects, the pixels are arranged in a grid pattern, such as 2x2, 3x3, 4x4, 5x5, 6x6, 7x7, 8x8, 9x9, or 10x10. In some aspects, the pixels are arranged in other patterns, such as 1x2, 1x3, 1x4, 1x5, 1x6, 1x7, 1x8, 1x9, 1x10, 2x3, 2x4, 2x5, 2x6, 2x7, 2x8, 2x9, 2x10, 3x4, 3x5, 3x6, 3x7, 3x8, 3x9, 4x5, 4x6, 4x7, 4x8, 4x9, 4x10, 5x6, 5x7, 5x8, 5x9, 5x10, 6x7, 6x8, 6x9, 6x10, 7x8, 7x9, 7x10, 8x9, 8x10, or 9x10. In some aspects, each of the aforementioned pixels canhave the same or different dimensions. In some aspects, liquid crystal devices or windows herein contain only one pixel.Orientation Layer

[0054] In some aspects, any liquid crystal device or cell disclosed herein includes at least one orientation layer. In some aspects, a liquid crystal device or cell has one orientation layer. In some aspects, a liquid crystal device or cell has more than one orientation layer, such as first and second orientation layers. In some aspects, the at least one orientation layer (e.g., first and second orientation layers) is disposed between first and second electrodes, as described elsewhere herein. In some aspects, the at least one orientation layer imparts alignment to the liquid crystal layer. In this regard, and without wishing to be bound by theory, it is believed directionality of the orientation layer causes molecules in the liquid crystal layer to become aligned so as to provide a longer range order to the molecules (e.g., molecules from the liquid crystal layer that are in contact with the orientation layer are aligned with the orientation layer, and then those aligned molecules cause nearby molecules to also align). It is to be understood that while every single molecule in the liquid crystal layer is not necessarily aligned as a result of the orientation layer, there is nevertheless a portion of such molecules that are aligned so as to provide a macroscopic effect, such as a change in visible light transmittance.

[0055] In some aspects, the at least one orientation layer (e.g., first and second orientation layers) facilitate alignment of liquid crystals in a liquid crystal layer. In some aspects, each orientation layer independently comprises a thin film of material having a surface energy and anisotropy promoting a desired or predetermined orientation for the liquid crystals in direct contact with its surface. In some aspects, exemplary materials include, but are not limited to, a grating; main chain or side chain polyimides, which can be mechanically rubbed to generate layer anisotropy; photosensitive polymers, such as azobenzene-based compounds, which can be exposed to linearly polarized light to generate surface anisotropy; inorganic thin films, such as silica, which can be prepared using thermal evaporating techniques to form periodic microstructures on the surface; or any combination thereof. In some aspects, organic orientation layers promoting vertical or homeotropic orientation of the liquid crystal molecules may be rubbed to create different pretilt angles other than 90° with respect to the plane of the substrate. In some aspects, the pretilt angle of the liquid crystal molecules with respect to the substrate surface will break the symmetry during switching from vertical orientation and can define an azimuthal direction of liquid crystal switching.

[0056] In some aspects, organic orientation layers may be deposited, for example, by spincoating a solution onto a desired surface or using printing techniques. In some aspects, inorganic orientation layers can be deposited using thermal evaporation techniques. In some aspects, any orientation layer(s) present in the liquid crystal device or cell can have, for example, a thickness of less than or equal to 100 nm, for example, ranging from 1 nm to 100 nm, from 5 nm to 90 nm, from 10 nm to 80nm, from 20 nm to 70 nm, from 30 nm to 60 nm, or from 40 nm to 50 nm, including all ranges and subranges therebetween.

[0057] In some aspects, at least one orientation layer is or comprises a grating. In some aspects, the liquid crystal device or cell comprises a first orientation layer comprising a grating. In some aspects, the liquid crystal device or cell comprises a first orientation layer comprising a grating and a second orientation layer comprising a polymer (e.g., a rubbed polymer). In some aspects, the liquid crystal device or cell comprises first and second orientation layers in which both orientation layers comprise gratings. In some aspects, the liquid crystal device or cell comprises first and second orientation layers, and at least one of the first and second orientation layers comprises a grating.

[0058] The grating can be any known grating in the art and can be prepared by known techniques. Such gratings and techniques for making include those described in (1) Wood et al., “Zenithal Bistable Device (ZBD™) Suitable for Portable Applications,” 31, 1, Society for Information Display (SID), May 2000, pp. 124-127; (2) Jones, “The Zenithal Bistable Display: From concept to consumer,” 16, 1, Society for Information Display (SID), January 2008, pp. 143-154; and (3) Jones et al., “Invited Paper. Low Cost Zenithal Bistable Display with Improved White State,” 41, 1, Society for Information Display (SID), May 2010, pp. 207-210; each of which is incorporated herein in its entirety for all purposes. For example, the grating can be produced using standard photolithography techniques, which can include preparing a grating master using hard-contact photolithograph, embossing an uncured photopolymer with the grating master, and photocuring the photopolymer to result in the grating. Any suitable photopolymer may be used to form the grating.

[0059] In some aspects, the grating has any suitable pitch, such as a pitch of 0.1 microns to 2 microns. For example, the pitch (microns) is 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, or any range formed from any two of the foregoing numbers, such as the nonlimiting examples 0.1-2, 0.2-1.9, 0.3-1.8, 0.4-1.7, 0.5-1.6, 0.6-1.5, 0.7-1.4, 0.8-1.3, 0.9-1.2, 1-1.1, 0.6-1, 0.7-0.9, 0.5-0.9, or 0.7-1.5. Generally, the pitch is the distance between adjacent peaks. In some aspects, the pitch is generally uniform throughout the grating. In some aspects, the pitch is not generally uniform throughout the grating because particular areas of the grating have varied pitches or the pitch changes continuously across certain areas. If the pitch is generally uniform throughout the grating, then the pitch is the distance between two adjacent peaks. If the pitch is not generally uniform throughout the grating, then the pitch is an average of a group of 25 adjacent peaks for a particular area (and in such an aspect, the foregoing numbers in this paragraph are in reference to an average pitch). In some aspects, the grating has a uniform pitch that is 0.6-1 microns or 0.8 microns, or any other number or range disclosed herein. In some aspects, any pitch in this paragraph (or elsewhere herein) can be combined with any depth in the following paragraph (or elsewhere herein) to form a pitch / depth pair to describe a grating.

[0060] In some aspects, the grating has any suitable depth, such as a depth of 0. 1 microns to 2 microns. For example, the depth (microns) is 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, or any range formed from any two of the foregoing numbers, such as the nonlimiting examples 0.1-2, 0.2-1.9, 0.3-1.8, 0.4-1.7, 0.5-1.6, 0.6-1.5, 0.7-1.4, 0.8-1.3, 0.9-1.2, 1-1.1, 0.9-1.3, 1-1.2, 0.8-1.2, or 1-1.8. Generally, the depth is the height of a peak relative to the adjacent valley. In some aspects, the depth is generally uniform throughout the grating. In some aspects, the depth is not generally uniform throughout the grating because particular areas of the grating have varied depth or the depth changes continuously across certain areas. If the depth is generally uniform throughout the grating, then the depth is the heigh of a peak relative to the adjacent valley. If the depth is not generally uniform throughout the grating, then the depth is an average of a group of adjacent 25 peak / valley pairs for a particular area (and in such an aspect, the foregoing numbers in this paragraph are in reference to an average depth). In some aspects, the grating has a uniform depth that is 0.8-1.3 microns or 1. 1 microns, or any other number or range disclosed herein. In some aspects, any depth in this paragraph (or elsewhere herein) can be combined with any pitch in the preceding paragraph (or elsewhere herein) to form a pitch / depth pair to describe a grating.

[0061] In some aspects, a grating has a sinusoidal shape. In some aspects, a grating can be uniform and have a pitch of 0.6-1 microns and a depth of 0.8-1.3 microns. In some aspects, a grating can be uniform and have a pitch of 0.8 microns and a depth of 1.1 microns.

[0062] In some aspects, at least one of the first and second orientation layers is a grating having a grating direction, and the grating direction is 30-60 degrees (e.g., 35-55, 40-50, or about 45 degrees) relative to the first and / or second transmission axes of the first and second polarizers, respectively.

[0063] In some aspects, the first and second transmission axes of the first and second polarizers are orthogonal to each other, and the grating direction is 30-60 degrees (e.g., 35-55, 40-50, or about 45 degrees) relative to the transmission axis of the first or second polarizer. In some aspects, the first and second transmission axes of the first and second polarizers are parallel to each other, and the grating direction is 30-60 degrees (e.g., 35-55, 40-50, or about 45 degrees) relative to the transmission axis of the first or second polarizer. In some aspects, the nematic liquid crystal layer has the following properties: An*(cell gap) / ! is in the range 0.9-1.1 for X = 0.55 pm, in which An is the birefringence of the nematic liquid crystal, cell gap is the thickness of the liquid crystal layer, and X is the wavelength of incident light.Liquid Crystal Layer

[0064] In some aspects, any liquid crystal device or cell disclosed herein includes at least one liquid crystal layer. In some aspects, a liquid crystal device or cell has one liquid crystal layer. In some aspects, a liquid crystal device or cell has more than one liquid crystal layer, such as first and second liquid crystal layers, and characteristics and properties of each liquid crystal layer can be independently selected and can be the same or different from other liquid crystal layers. In someaspects, the at least one liquid crystal layer is disposed between first and second orientation layers (or at least between one orientation layer and another feature, such as an electrode), as described elsewhere herein. In some aspects, the liquid crystal layer is in direct contact with an orientation layer which facilitates the orientation layer imparting alignment to the liquid crystal molecules in the liquid crystal layer.

[0065] In some aspects, a liquid crystal layer is in electrical communication with the first and second electrodes. In some aspects, this electrical communication is by way of an applied voltage across the first and second electrodes. In some aspects, this electrical communication is by way of an electric field.

[0066] In some aspects, the orientation of liquid crystal layer can be described by a unit vector, referred to herein as a “director,” which represents the average local orientation of the long molecular axes of the liquid crystal molecules. A vertical alignment or homeotropic state is achieved when the liquid crystal director has a perpendicular or substantially perpendicular orientation with respect to the plane of the liquid crystal device or cell (e.g., the plane of any of the orientation layer, electrode, and / or substrate). A planar alignment (homogeneous state or low pre-tilt) is achieved when the liquid crystal director has a parallel or substantially parallel orientation with respect to the plane of the liquid crystal device or cell (e.g., the plane of any of the orientation layer, electrode, and / or substrate). An oblique alignment or grayscale state is achieved when the liquid crystal director has a large angle with respect to the plane of the liquid crystal device or cell (e.g., the plane of any of the orientation layer, electrode, and / or substrate), which is substantially different from planar or homeotropic, i.e., ranging from 20° to 70°, such as from 30° to 60°, or from 40° to 50°, including all ranges and subranges therebetween. In some aspects, the liquid crystal comprises multiple stable states (e.g., first and second stable states), and at least one of the stable states (e.g., the first and / or second stable state) comprises liquid crystals (e.g., nematic liquid crystals) aligned substantially perpendicular (e.g., within 10 degrees) to at least one of the first orientation layer, the second orientation layer (if present), the first electrode, and the second electrode, and another of the stable states comprises liquid crystals aligned substantially parallel (e.g., within 10 degrees) to at least one of the first orientation layer, the second orientation layer (if present), the first electrode, and the second electrode. In some aspects, the orientation layers and electrodes are in planes that are parallel to each other, such that the liquid crystals are perpendicular or parallel to all of the orientation layers and electrodes.

[0067] In some aspects, the first orientation layer aligns at least a portion of the nematic liquid crystal in a first orientation or in a second orientation near the first orientation layer, in which at least a portion of the liquid crystal layer stays in a first stable state at zero voltage when the nematic liquid crystal is aligned in the first orientation and in a second stable state at zero voltage when the nematic liquid crystal is aligned in the second orientation.

[0068] In some aspects, any liquid crystal layer in the liquid crystal device or cell disclosed herein can comprise a cell gap or cavity filled with liquid crystals. The thickness of the liquid crystal layer, or the cell gap distance, can be maintained by particle spacers and / or columnar spacers dispersed and / or otherwise situated in the liquid crystal layer. The liquid crystal layers can have a thickness of less than or equal to 0.2 mm, for example, ranging from 0.001 mm to 0.1 mm, from 0.002 mm to 0.05 mm, from 0.003 mm to 0.04 mm, from 0.004 mm to 0.03 mm, from 0.005 mm to 0.02 mm, or from 0.01 mm to 0.015 mm, including all ranges and subranges therebetween. If more than one liquid crystal layer is present in the window, these layers may each have the same thickness or each may have different thicknesses.

[0069] In some aspects, any liquid crystal layer can comprise liquid crystals (i.e., liquid crystal molecules) and one or more additional components, such as dyes or other coloring agents (e.g., to absorb light transmitted through the liquid crystal layer), chiral dopants, polymerizable reactive monomers, photoinitiators, polymerized structures, or any combination thereof. Liquid crystals can have any liquid crystal phase, such as achiral nematic liquid crystal (NLC), chiral nematic liquid crystal or cholesteric liquid crystal (CLC), or smectic liquid crystal, which are operable over a broad range of temperatures, such as from -20 °C to 100 °C.

[0070] In some aspects, the liquid crystal layer comprises a nematic liquid crystal. In some aspects, the liquid crystal layer comprises a bistable liquid crystal. In some aspects, the liquid crystal layer comprises a nematic bistable liquid crystal. In some aspects, the liquid crystal layer comprises a dichroic dye. In some aspects, the liquid crystal layer is substantially free of or does not include a dichroic dye. In some aspects, the liquid crystal layer comprises a chiral dopant. In some aspects, the liquid crystal layer is substantially free of or does not include a chiral dopant. In some aspects, inclusion of a chiral dopant may not substantially change visible light transmittance in one stable state (e.g., the “light” stable state), but the chiral dopant may change the visible light transmittance of another stable state (e.g., the “dark” stable state). In some aspects, a dye that is not dichroic is included in the liquid crystal layer or in another layer of the liquid crystal cell or liquid crystal device, for example, to provide color to the liquid crystal device. In some aspects, the liquid crystal layer comprises a chiral liquid crystal. In some aspects, the liquid crystal layer is substantially free of or does not include a chiral liquid crystal. In some aspects when a dichroic dye is included, at least a portion of the dichroic dye aligns with the liquid crystal in the stable states of the liquid crystal, such as the first and second stable states. In some aspects, the dichroic dye absorbs more visible light when aligned with one stable state (e.g., first or second stable state) compared to the another stable state (e.g., the other of the first or second stable states).

[0071] In some aspects, any suitable amount of dichroic dye is included. The amount of dichroic dye is not particularly limited and may be selected so as to achieve a desired visible light transmittance of a liquid crystal cell. For example, the amount (wt.%) of dichroic dye and cell gap canbe tuned to control the visible light transmittance when the liquid crystal is aligned vertically or horizontally through the cell thickness according to the following relationship:

[0072] In this relationship, Tught is the visible light transmittance of the liquid crystal cell in the “light” stable state, To is the visible light transmittance without any dichroic dye present, c is a coefficient related to dye’s absorption properties, wt. % is the amount of dichroic dye present relative to the total mass of liquid crystal layer, and gap is the thickness of the liquid crystal layer. Generally, To is about 90%, but can be larger or smaller depending on materials employed in the liquid crystal cell. By controlling the product of wt. % x gap. the visible light transmittance of Tught can be adjusted to any value disclosed elsewhere herein, such as at least 45% or at least 85%. However, smaller visible light transmittance values can be attained as desired, such as less than 45% or less than 20%.

[0073] In some aspects, the liquid crystal layer comprises a dichroic dye. In general, dichroic dyes have light absorption properties that depend on their orientation relative to the propagation and / or polarization directions of incident light. For example, and without wishing to be bound by theory, dichroic dyes typically absorb light more strongly along a direction parallel to the direction of a transition dipole moment in the dye molecule, which is typically the longer molecular axis of the dye molecule. Dye molecules oriented with their long axis perpendicular to the direction of light polarization generally will provide low light attenuation, whereas dye molecules oriented with their long axis parallel to the direction of light polarization generally will provide strong light attenuation. In some aspects, the dichroic dye can have any suitable absorption properties to impart a color to the liquid crystal layer when aligned in a desired direction. In some aspects, the color is black, which maximizes contrast between “light” and “dark” states. However, the color can be any other color, such as red, orange, yellow, green, blue, indigo, violet, pink, purple, or any combination thereof. In some aspects, the dichroic dye is a black dichroic dye. In some aspects, the dye facilitates achieving a higher contrast ratio between “light” and “dark” states.

[0074] In some aspects, the liquid crystal layer comprises at least one chiral dopant. Non-limiting examples of chiral dopants include R811, S8I I, RI0I I, S 1011, R5011, and S5011 available from Merck. In some aspects, the chiral dopant imparts a rotation to the liquid crystal about an axis when in at least one of the first stable state and the second stable state. In some aspects, the chiral dopant imparts a rotation to the liquid crystal about an axis when in the stable state corresponding to the “dark” state or the “light” state, or both the “dark” and “light” states. In some aspects, the axis is parallel or perpendicular to the plane of the liquid crystal cell (e.g., the plane of any of the orientation layer, electrode, and / or substrate). In some aspects, a total rotation angle of the liquid crystal from the first orientation layer to the second orientation layer (or relative to the thickness of the liquid crystal layer perpendicular to the liquid crystal cell plane) (degrees) is 45, 90, 180, 270, 360, 450, 540, 630, 720, 810, 900, 990, 1080, 1170, 1260, 1350, 1440, 1530, 1620, 1710, 1800, 1890, 1980, 2070, 2160,2250, 2340, 2430, 2520, 2610, 2700, 2790, 2880, 2970, 3060, 3150, 3240, 3330, 3420, 3510, 3600, or any range that can be made from any two of the foregoing numbers, such as 45-3600, 180-3510, 360- 3060, 45-1260, 720-1710, 1080-2250, 1980-2970, or 2610-3510.

[0075] In some aspects, the rotation of a liquid crystal layer comprising at least one chiral dopant can be quantified by a ratio (d / p) of cell gap thickness (d) to helical pitch (p). For liquid crystal applications, the amount of chiral dopant dissolved in the liquid crystal mixture can be controlled to achieve a desired amount of rotation across a given cell gap distance. It is within the ability of one skilled in the art to select the appropriate dopant and its amount to achieve the desired rotation effect. The pitch of the liquid crystal determines the wavelengths of light that are reflected by the liquid crystal. The range of reflected wavelengths (R) is defined by p*n0< R < p*ne, where ne> n0and neis the extraordinary refractive index and n0is the ordinary refractive index of the liquid crystal. In some aspects, the d / p can be 0 to 10, 2 to 10, 3-8, 0.1 to 2, 0.1 to 1, 0.2 to 0.8, 0.4 to 0.6, 0.5 to 5, 0.5 to 1, 0.25 to 2, 0.125 to 3, or 0.8 to 1.7.

[0076] In some aspects, the liquid crystal layer can be any suitable liquid crystal known in the art. For example, in some aspects the liquid crystal layer comprises a cyano-biphenyl, a cyanoterphenyl, N-(4-methoxybenzylidene)-4-butylaniline (MBBA), or any combination thereof. In some aspects, the liquid crystal layer comprises only one type of liquid crystal material. In some aspects, the liquid crystal layer comprises a plurality of liquid crystal materials, such as two, three, four, five, or more liquid crystal materials. In some aspects, the liquid crystal layer can include a first liquid crystal material and a second liquid crystal material. In some aspects, the ratio (by weight) of the first liquid crystal material to the second liquid crystal material may be in the range of 1:99 to 99: 1, including from 10:90 to 90: 10, 20:80 to 80:20, 70:30 to 30:70, 40:60 to 60:40, 45:55 to 55:45, or 50:50, including all ranges and subranges therebetween.

[0077] In some aspects, any liquid crystal device or cell disclosed herein comprises first and second electrodes and at least one orientation layer (e.g., first and second orientation layers), and at zero applied voltage to the first and second electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state by way of alignment imparted by the at least one orientation layer (e.g., the first and second orientation layers). In such aspects, at least a portion of the liquid crystals can be aligned in either a first stable state or a second stable at zero applied voltage, which generally means that the liquid crystal device or cell comprising such liquid crystals consumes no power (or substantially no power) in either the “dark” or “light” states. In other words, in such aspects, at least a portion of the liquid crystals is aligned in a first stable state, and upon an appropriate stimulus, at least a portion of the liquid crystals becomes aligned in a second stable state (e.g., and both the first and second stable states have different transmittance s to visible light, such as a difference of at least 20% as discussed elsewhere herein). In a multi stable state system, two or more stable states of the liquid crystal are possible, such as two, three, four, five, or sixstable states. Generally, however, two stable states corresponding to “light” and “dark” states are desired so as to provide a liquid crystal device or cell that either allows or prevent light transmittance through the liquid crystal device or cell. In some aspects, the liquid crystal is a bistable liquid crystal. In some aspects, the liquid crystal is a nematic bistable liquid crystal. In some aspects, the liquid crystal (e.g., nematic liquid crystal) is aligned in at least one of a continuous texture or a defect texture, and in some aspects such continuous or defect textures correspond to at least one of the first and stable states of the liquid crystal.

[0078] In some aspects, one stable state (e.g., a first stable state) of the liquid crystal is switchable to another stable state (e.g., a second stable state) by application of a first stimulus. In some aspects, this process is reversible, such that application of a second stimulus switches back to the first stable state. In this regard, the first stable state is switchable to the second stable state by application of a first stimulus, and the second stable state is switchable to the first stable state by application of a second stimulus, in which the first and second stimuli can be the same or different. In some aspects, the first and second stimuli are the same magnitude but opposite in sign, as described elsewhere herein. The methods disclosed elsewhere herein are applicable to the stimuli referenced herein with respect to switching between stable states (e.g., between first and second stable states).Substrates

[0079] In some aspects, any liquid crystal device or cell herein can comprise one or more substrates. In some aspects, the one or more substrates comprise first and second substrates. In some aspects, the one or more substrates comprise first, second, and third substrates. In some aspects, the one or more substrates comprise first, second, third, and fourth substrates. In some aspects, any or all of the substrates can be optically transparent. In some aspects, a liquid crystal device or cell comprises at least one substrate that is optically transparent.

[0080] In some aspects, any liquid crystal device or cell herein can comprise at least one substrate. In some aspects, a liquid crystal device or cell comprises first and second (e.g., glass) substrates. In some aspects, first and second electrodes are disposed between the first and second (e.g., glass) substrates. In some aspects, first and second (e.g., glass) substrates are disposed between the first and second electrodes. In some aspects, an orientation layer (e.g., grating) is formed into at least one of the first and second electrodes. In some aspects, an orientation layer (e.g., grating) is formed into at least one of the first and second (e.g., glass) substrates. In some aspects, any liquid crystal device or cell herein can comprise first and second electrodes and first and second glass substrates, the first and second electrodes are disposed between the first and second glass substrates, and optionally at least one of the first and second orientation layers comprises a grating formed into at least one of the first and second electrodes.

[0081] In some aspects, any liquid crystal device herein can further comprise third and fourth (e.g., glass) substrates, the first and second (e.g., glass) substrates are disposed between the third andfourth (e.g., glass) substrates, the first and third (e.g., glass) substrates being proximal to and optionally bonded to one another and the second and fourth (e.g., glass) substrates being proximal to and optionally bonded to one another. In some aspects, such bonding can be accomplished by melting and / or with adhesive (e.g., an optically clear adhesive such as polyacrylates, as is known in the art). In some aspects, at least one of the first, second, third, and fourth (e.g., glass) substrates has a UV transmittance of less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, less than 0.5%, or less than 0.1%. In some aspects, the first, second, third, and / or fourth (e.g., glass) substrates provide UV protection for the first and second orientation layers, the liquid crystal layer, and the first and second polarizers (if present). In some aspects, first and second glass substrates are present, and only one of the third and fourth glass substrates has UV protection (e.g., whichever of the third and fourth glass substrates is toward the exterior of the liquid crystal device so as to provide UV protection for all components toward the interior of the liquid crystal device or cell).

[0082] In some aspects, at least one of the first, second, third, and fourth (e.g., glass) substrates comprises a low-emissivity (Uow-E) material, such as a Uow-E glass. In some aspects, at least one of the first, second, third, and fourth (e.g., glass) substrates (or any other layer or component disclosed herein, such as an electrode, other substrate, and so forth) comprises a coating that minimizes an amount of infrared and / or ultraviolet light transmittance through the liquid crystal device or cell while minimizing or not affecting the amount of visible light transmittance through the liquid crystal device or cell. Any suitable coating for such purpose known in the art can be used, such as Thinsulate™ available from 3M and other similar coatings.

[0083] In some aspects, any substrate in any liquid crystal device or cell herein can comprise a glass sheet. In some aspects, any substrate can have any shape and / or size, such as a rectangle, square, or any other suitable shape, including regular and irregular shapes and shapes with one or more curvilinear edges, or any combination of such shapes and / or sizes. In some aspects, any substrate has a thickness (mm) of 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.2, 1.4, 1.5, 1.6, 1.8, 2, 2.2, 2.4, 2.5, 2.6, 2.8, 3, 3.2, 2.4, 2.5, 3.6, 3.8, 4, 5, 6, 7, 8, 9, or 10 mm, or any range that can be formed from any two of the foregoing numbers, such as 0.01-4, 0.1-4, 0.2-3, 0.3-2, 0.5-1.5, 0.6-1, 0.8-1, 1-3, 1.5-2, 1-2, 1-3, 1-4, 1-5, 1-6, 1-7, 1-8, 1-9, 1-10, 2-3, 2-4, 2-5, 2-6, 2-7, 2-8, 2-9, 2-10, 3-4, 3-5, 3-6, 3-7, 3-8, 3-9, 3-10, 4-5, 4-6, 4-7, 4-8, 4-9, 4-10, 5-6, 5-7, 5-8, 5-9, 5-10, 6-7, 6-8, 6-9, 6-10, 7-8, 7-9, 7-10, 8-9, 8-10, or 9-10, and so forth. In aspects where more than one substrate is present, each such substrate independently has any of the foregoing thicknesses. In some aspects, the first and second substrates are generally thinner (e.g., 0.01-2 mm) than the third and fourth substrates (e.g., 2-10 mm) because, in some aspects, the third and / or fourth substrates are present to provide additional structural integrity.

[0084] In some aspects, if the liquid crystal device or cell comprises one or more glass substrates (e.g., first, second, third, and / or fourth glass substrates), then each such glass substrate canindependently comprise any glass known in the art, such as soda-lime silicate, aluminosilicate, alkalialuminosilicate, borosilicate, alkaliborosilicate, aluminoborosilicate, alkali-aluminoborosilicate, or other suitable display glasses. In some aspects, the first, second, third, and / or fourth substrates independently can comprise thermally strengthened glass, chemically strengthened glass, tempered glass, or any combination thereof. Non-limiting examples of suitable commercially available glasses include EAGLE XG®, Lotus™, Willow®, and Gorilla® glasses from Coming Incorporated, to name a few. Chemically strengthened glass, for example, may be provided in accordance with U.S. Patent Nos. 7,666,511, 4,483,700, and 5,674,790, each of which is incorporated herein by reference in its entirety for all purposes. When third and / or fourth substrates are present, such substrates may provide mechanical strength against damage from external forces, such as consumers, pets, weather, and so forth.

[0085] In some aspects, the glass substrates may be chosen from glass sheets produced by a fusion draw process. Without wishing to be bound by theory, it is believed that the fusion draw process can provide glass sheets with a relatively low degree of waviness (i.e., a high degree of flatness), which may be beneficial for various liquid crystal applications. An exemplary glass substrate may thus, in certain aspects, comprise a surface waviness of less than about 100 nm as measured with a contact profilometer, such as about 80 nm or less, about 50 nm or less, about 40 nm or less, or about 30 nm or less, including all ranges and subranges therebetween. An exemplary standard technique for measuring waviness (0.8~8mm) with a contact profilometer is outlined in SEMI D 15-1296 “FPD Glass Substrate Surface Waviness Measurement Method,” incorporated herein by reference in its entirety for all purposes.Interlayer

[0086] In some aspects, any liquid crystal device herein can comprise at least one interlayer. In some aspects, the at least one interlayer can improve the safety of the liquid crystal device, for example, by holding one or more (e.g., glass) substrates in place in case of breakage, and / or preventing shattering of one or more (e.g., glass) substrates which can present a safety hazard without such an interlayer(s).

[0087] In some aspects, a liquid crystal window comprises first and second (e.g., glass) substrates and first and second electrodes, and an interlayer is present between at least one of the substrate / electrode interfaces. In some aspects, a liquid crystal window comprises first, second, and third (e.g., glass) substrates, and at least one interlayer is present between at least one of the substrate / substrate interfaces. In some aspects, a liquid crystal window comprises first, second, third, and fourth (e.g., glass) substrates, and at least one interlayer is present between at least one of the substrate / substrate interfaces (e.g., first / third substrate interface and / or second / fourth substrate interface). In some aspects, at least one interlayer is present between a third glass substrate and a first polarizer. In some aspects, at least one interlayer is present between a fourth glass substrate and asecond polarizer. In some aspects, at least one interlayer is present between a third glass substrate and a cavity containing an insulating gas. In some aspects, at least one interlayer is present between a fourth glass substrate and a cavity containing an insulating gas.

[0088] In some aspects, interlayers can comprise one or more materials comprising polyvinyl butyral (PVB), ethylene -vinyl acetate (EVA), polylactic acid, polyurethanes, ionoplast polymer such as SentryGlas® and SentryGlas® Plus from DuPont, other suitable materials, or any combination thereof.

[0089] In some aspects, an interlayer provides UV and / or IR protection for components of the liquid crystal device or cell, such as polarizers, orientation layers, liquid crystal layer, electrodes, substrates, and so forth. In some aspects, the UV and / or IR transmittance of an interlayer, or a combination of interlayers, is less than 5%, such as less than 2%, less than 1%, less than 0.5%, or less than 0.1%, including all ranges and subranges therebetween. In some aspects, if more than one interlayer is present, they may have the same UV and / or IR transmittance, or different transmittances. In some aspects, an interlayer toward the exterior of the liquid crystal device has UV and / or IR protection, and an interlayer toward the interior of the liquid crystal device does not have UV and / or IR protection because the exterior facing interlayer (and / or other components, substrates, or coatings) provides sufficient UV and / or IR protection.

[0090] In some aspects, any liquid crystal device herein can comprise an interlayer disposed between any electrode and substrate, between any two substrates, between any polarizer and a substrate, between any polarizer and a cavity filled with insulating gas, and so forth. In some aspects, a first interlayer is disposed between first and third glass substrates; and / or a second interlayer is disposed between a second and fourth glass substrate.Insulating Gas

[0091] In some aspects, any liquid crystal device herein can comprise at least one gap (i.e., cavity) comprising an insulating gas. In some aspects, the insulating gas provides thermal insulation to the liquid crystal device or cell, including the components that are more interior to liquid crystal device or cell than the gap comprising the insulating gas. In some aspects, at least one gap is located between two substrates (e.g., between first and third glass substrates, and / or between second and fourth glass substrates). In some aspects, at least one gap is located between an electrode and a substrate (e.g., between a first electrode and a first glass substrate, and / or between a second electrode and a second glass substrate). In some aspects, there are multiple gaps filled with an insulating gas, such as gaps positioned between substrates, between substrate / electrode, between substrate / polarizer, between electrode / polarizer, electrode / orientation layer, polarizer / orientation layer, substrate / orientation layer, and so forth (e.g., between first and third glass substrates, between second and fourth glass substrates, between a first electrode and a first glass substrate, between a second electrode and a second glass substrate, etc.). When multiple gaps comprising insulating gas arepresent, each gap can contain the same or different insulating gases. In some aspects, the insulating gas can be any suitable insulating gas, such as nitrogen, argon, helium, carbon dioxide, carbon monoxide, ambient air, or any combination thereof. In some aspects, the gaps include one or more spacers, for example, to maintain structural integrity of the gap. In some aspects, one or more spacers are included between a first glass substrate of a liquid crystal cell and a third glass substrate to define a gap. In some aspects, one or more spacers are included between a second glass substrate of a liquid crystal cell and a fourth glass substrate to define a gap. The terms “gap” and “cavity” are used interchangeably herein.Polarizers

[0092] In some aspects, any liquid crystal device or cell disclosed herein includes at least one polarizer. In some aspects, a liquid crystal device or cell has one polarizer. In some aspects, a liquid crystal device or cell has more than one polarizer, such as first and second polarizers, and characteristics and properties of each polarizer can be independently selected and can be the same or different from other polarizers.

[0093] In some aspects, each polarizer has a transmission axis. For example, when first and second polarizers are present, the first and second polarizers have first and second transmission axes, respectively. In some aspects, the first and second transmission axes are orthogonal. In some aspects, the first and second transmission axes are parallel. In some aspects, the first and second transmission axes have any angle therebetween (e.g. 1, 5, 10, 15, 20, 25, 30, 35, 40, or 45 degrees therebetween, or any range formed from any two of the foregoing numbers).

[0094] In some aspects, the polarizers (e.g., first and second polarizers) are located in any suitable position in the liquid crystal cell or device. In some aspects, the first and second electrodes are disposed between the first and second polarizers. In some aspects, the first and second polarizers are disposed between first and second substrates, which arrangement facilitates the ability of the first and second polarizers to withstand (be stable to) downstream high temperature lamination processes. In some aspects, the first and second substrates are disposed between the first and second polarizers. In some aspects, the one of the first and polarizers is disposed between the first and second substrates, and the other of the first and second polarizers is disposed outside of (i.e., not between) the first and second substrates. In some aspects, other arrangements are contemplated, as disclosed elsewhere here, particularly with respect to the FIGs.

[0095] In some aspects, the polarizers (e.g., first and second polarizers) are stable at high temperatures, such as temperatures (°C) of at least 100 (e.g., at least 110, at least 120, at least 130, at least 140, at least 150, at least 160, at least 170, at least 180, at least 190, or at least 200; alternatively or additional less than 210, less than 200, less than 190, less thanl80, less than 170, less than 160, less than 150, less than 140, less than 130, less than 120, or less than 110; or any range formed therebetween) for a period (hour) of at least 1 (e.g., at least 1.5, at least 2, at least 2.5, at least 3, atleast 3.5, at least 4, at least 4.5, at least 5, at least 5.5, at least 6, at least 7, at least 8, at least 9, or at least 10; alternatively, or additionally, less than 11, less than 10, less than 9, less than 8, less than 7, less than 6, less than 5.5, less than 5, less than 4.5, less than 4, less than 3.5, less than 3, less than 2.5, less than 2, or less than 1.5; or any range formed therebetween). In some aspects, the polarizers (e.g., first and second polarizers) are stable at a temperature of at least 140 °C for a time period of at least 1 hour. In some aspects, the polarizers are stable to downstream lamination processes (e.g., which in some aspects employ high temperature for a period of time).

[0096] In some aspects, the polarizers (e.g., first and second polarizers) are dye-type polarizers. In some aspects, the dye-type polarizers are those commercially available under the brand name POLATECHNO from Nippon Kayaku, such as GHC type, VHC type, or SHC type polarizers, each of which have optics wavelengths in the visible light range.. GHC type polarizers have high durability and high contrast, maintaining polarization performance for a long time under severe environment conditions such as heat and light, with contrast of 15,000 or more. VHC type polarizers have high durability and high contrast, with contrast of 8,000 or more. SHC type polarizers have high durability.

[0097] In some aspects, the polarizers (e.g., first and second polarizers) are not iodine-doped stretched polyvinyl alcohol polarizers, or are substantially free of, or are not made of, iodine-doped stretched polyvinyl alcohol. Such iodine-doped stretched polyvinyl alcohol polarizers are conventional polarizers that generally change their color dramatically when subjected to typical lamination conditions (e.g., at least 100 °C, or at least 140 °C, for at least 1 hour). In this regard, the iodine-doped stretched polyvinyl alcohol polarizers are not stable to such lamination conditions and are not suitable for use in liquid crystal windows.Compensation Film

[0098] In some aspects, any liquid crystal device or cell disclosed herein includes at least one compensation film. In some aspects, a liquid crystal device or cell has one compensation film. In some aspects, a liquid crystal device or cell has more than one compensation film, such as first and second compensation films, and characteristics and properties of each compensation film can be independently selected and can be the same or different from other compensation films.

[0099] In some aspects, a compensation film is positioned between a polarizer and the liquid crystal layer. In some aspects, a compensation film is positioned between the first polarizer and the liquid crystal layer. In some aspects, a compensation film is positioned between the second polarizer and the liquid crystal layer. In some aspects, a compensation film is positioned between the first polarizer and the first electrode, as shown, e.g., in FIG. IB.

[0100] In some aspects, the at least one compensation film can be a discotic liquid crystal polymer. In some aspects, the optical axis of a compensation film is tilting in the thickness direction. In some aspects, a compensation film improves the viewing angle characteristic of the “dark” state of a liquid crystal device.Applications

[0101] In some aspects, the liquid crystal devices or cells disclosed herein can be used in various architectural and transportation applications. For example, the liquid crystal cells can be used in (e.g., as a component of) liquid crystal devices, such as liquid crystal windows that can be included in doors, space partitions, skylights, and windows for buildings, automobiles, and other transportation vehicles such as trains, planes, motorhomes, boats, and the like. In some aspects, the liquid crystal windows are switchable windows that can be switched from a light state to a dark state, and from a dark state to a light state, in which at zero applied voltage each of the light and dark states can be maintained for a period of time of at least 1 hour. Liquid crystal window devices for use in architectural applications can have any desired dimension including, but not limited to 2’ x 4’ (width x height), 3’ x 5’, 5’ x 8’, 6’ x 8’, 7 xlO’, 7’ x 12’. Larger and smaller liquid crystal devices (e.g., windows) are also envisioned and are intended to fall within the scope of this disclosure. In some aspects, any liquid crystal device (e.g., windows) disclosed herein can comprise one or more additional components such as a frame or other structural component, a power source, and / or a control device or system. In some aspects, any liquid crystal device or cell herein can be a component of a window or a display. In some aspects, multiple liquid crystal devices or cells disclosed herein, each of which can be the same or different, can be employed in combination to form a device having multiple such liquid crystal devices or cells. In some aspects, the liquid crystal device can be an insulating gas unit (IGU). In some aspects, the IGU can be incorporated in a window, which has one or more frames. In some aspects, the frame is made of any suitable material, such as wood, vinyl, aluminum, or any combination thereof. In some aspects, a liquid crystal device, window, and / or IGU can include a seal to maintain spacer integrity, prevent moisture from infiltrating into insulating gas cavities, and / or prevent leakage of the insulating gas from cavities. In some aspects, the seal is made of a polymer, such as though known in the art form such sealing purposes.Methods

[0102] Various methods are applicable to the liquid crystal devices or cells disclosed elsewhere herein. In this regard, any liquid crystal device or cell disclosed herein may be the subject of the methods disclosed hereinbelow (or elsewhere herein).Methods of Switching

[0103] In some aspects, at zero applied voltage to first and second electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state by way of alignment imparted by at least one of the first and second orientation layers. In some aspects, the first stable state is switchable to the second stable state by application of a first stimulus, and the second stable state is switchable to the first stable state by application of a second stimulus. Such features are discussed elsewhere herein and are applicable here with respect to methods of switching betweenstable states. Likewise, all features disclosed herein with respect to methods of switching between stable states (e.g., between a first stable state and a second stable state and vice versa), including application of a stimulus to switch between such stable states (e.g., applicable of a first stimulus and / or a second stimulus), are equally applicable to any disclosures herein with respect to any liquid crystal device or cell (e.g., the details concerning the stimuli such as the at least one voltage pulse and polarities thereof). In some aspects, the liquid crystals are switched between stable states by way of a direct driving method (as compared to a passive matrix method).

[0104] In some aspects, disclosed is a method for switching any liquid crystal device or cell disclosed herein, the method comprising: when in a first stable state, applying to first and second electrodes a first stimulus comprising at least one first voltage pulse comprising the first polarity to switch the first stable state to a second stable state; and / or when in the second stable state, applying to the first and second electrodes a second stimulus comprising at least one second voltage pulse comprising the second polarity to switch the second stable state to the first stable state.

[0105] In some aspects, any suitable voltage magnitude can be employed that is sufficient to switch the liquid crystal layer from a first stable state to a second stable state. In some aspects, at least one of the first and second voltage pulses is 55 V or less, 50 V or less, 45 V or less, 40 V or less, 35 V or less, 30 V or less, 25 V or less, 24 V or less, 20 V or less, 15 V or less, 10 V or less, 9 V or less, 8 V or less, 7 V or less, 6 V or less, 5 V or less, 4 V or less, 3 V or less, 2 V or less, 1 V or less, or 0.5 V or less; alternatively, or additionally, at least one of the first and second voltage pulses is at least 0. 1 V, at least 0.5 V, at least 1 V, at least 2 V, at least 3 V, at least 4 V, at least 5 V, at least 6 V, at least 7 V, at least 8 V, at least 9 V, at least 10 V, at least 15 V, at least 20 V, at least 25 V, at least 30 V, at least 35 V, at least 40 V, at least 45 V, at least 50 V, or at least 55 V; or any range formed therebetween.

[0106] In some aspects, a stimulus (e.g., the first and / or second stimulus) can comprise one or more voltage pulses, one or more temperature changes, one or more irradiations with light having a given wavelength range, or any combination thereof. In some aspects, the first stimulus comprises at least one first voltage pulse comprising a first polarity. In some aspects, the second stimulus comprises at least one second voltage pulse comprising a second polarity. In some aspects, the first polarity and the second polarity are opposite in sign. In some aspects, the magnitude of the first polarity and the second polarity are the same or different. When the magnitude is different, the magnitude of each polarity is sufficient to switch from the first stable state to the second stable state and vice versa. In some aspects, the at least one first voltage pulse comprises one, two, three, four, five, or six voltage pulses. In some aspects, the at least one second voltage pulse comprises one, two, three, four, five, or six voltage pulses. In some aspects, a two-pulse sequence may be useful whenswitching a window comprising a single pixel, e.g., the entire window responds to the pulse sequence and switches to the desired state. In some aspects, a three-pulse sequence may be advantageous if a window is subdivided into multiple pixels, for example, a matrix of subpixels comprising two or more subpixels, three or more, four or more, and so forth. In such an instance, the first and third pulses can be uniformly applied to all subpixels, whereas different second pulses can be applied to each subpixel to achieve different desired stable states for each subpixel.

[0107] In some aspects, the first stimulus further comprises, prior to the at least one first voltage pulse comprising the first polarity, at least one first bipolar voltage pulse sufficient to lower a first magnitude of the at least one first voltage pulse necessary to switch the first stable state to the second stable state. In some aspects, the second stimulus further comprises, prior to the at least one second voltage pulse comprising the second polarity, at least one second bipolar voltage pulse sufficient to lower a second magnitude of the at least one second voltage pulse necessary to switch the second stable state to the first stable state. In some aspects, the duration of a bipolar voltage pulse can be between 1 millisecond and 2 seconds. Without wishing to be bound by theory, typically the voltage level of the bipolar voltage pulses decreases with the time duration of the bipolar voltage pulses. For a typical display applications that require switching many rows of pixels, the time duration of the bipolar voltage pulses should be short, such as shorter than 10 milliseconds. In a window application, the time duration of the bipolar voltage pulses can be much longer, for example, longer than 50, 100, 200, 500, 1000, or 2000 milliseconds, because the window has one pixel, or can be configured to have one or two rows of pixels. By increasing the time duration of the bipolar voltage pulses substantially, its voltage level can be reduced substantially, allowing power saving. Additionally, an orientation layer can induce liquid crystal in a low tilt state (also referred to as a defect state) or a high tilt state (also referred to as a continuous state). In some aspects, the low tilt state possesses a flexoelectric polarisation (P), which can couple to a DC component of an applied waveform. Thus the sign of a pulse which favours P will typically lead to the low-tilt state while that which is opposed to P will typically induce a high-tilt state. The low-tilt state to high-tilt state transition is also aided by the positive dielectric anisotropy of the nematic liquid crystal.

[0108] In some aspects, voltage is applied to a liquid crystal layer to change liquid crystals between different states (which allow different visible light transmittances). In some aspects, any combination of voltage, frequency, and duration can be employed herein for a given cell gap thickness. For example, voltage (which as used herein is root mean square (RMS) voltage) for a cell gap of 20 pm can range from 0. 1 volts to 55 volts. The duration in some aspects depends on the voltage: higher applied voltage can switch stable state faster than lower applied voltage. As a result, when the voltage is between 0.1 V and 55 V, the duration can range from 0.001 seconds to 2 seconds, and generally the voltage may be lower than 24 V (e.g., less than 9 V, or less than 5 V) and the duration between 0.1 and 2 seconds (e.g., 0. 1-1.8, 0.2-1.6, 0.3-1.4, 0.4-1.2, 0.5-1, or 0.6-0.8). In thisregard, when a matrix of pixels are employed, it is typically desired that the switching voltage pulse be short, such as around 5 milliseconds; in contrast, when only one or a few larger pixels are employed in the context of the present disclosure, longer pulse durations (e.g., 0. 1 to 2 seconds) paired with lower voltage (e.g., less than 24 V) is possible, resulting in lower energy consumption. The frequency can range from about 100 Hz to about 10,000 Hz, such as from about 500 Hz to about 9,000 Hz, from about 1,000 Hz to about 8,000 Hz, from about 2,000 Hz to about 7,000 Hz, from about 3,000 Hz to about 6,000 Hz, or from about 4,000 Hz to about 5,000 Hz, including all ranges and subranges therebetween.Methods of Making

[0109] Any liquid crystal device or cell disclosed herein can be prepared according to the methods of making disclosed herein.

[0110] In some aspects, disclosed is a method of making any liquid crystal device or cell disclosed herein, the method comprising, in any order: providing the first and second glass substrates, the first and second polarizers, the first and second electrodes, the first and second orientation layers, and the liquid crystal layer; disposing the first and second orientation layers between the first and second electrodes; and positioning the liquid crystal layer between the first and second orientation layers, [oni] In some aspects, the method of making can be performed in any order. In general, the order of providing the various structures is not critical provided that the final desired structure is obtained. For example, first the first and second orientation layers can be disposed between the first and second electrodes, and then the liquid crystal layer can be positioned between the first and second orientation layers. In other aspects, the liquid crystal layer and first be disposed on one side of a first orientation layer, followed by placing the second orientation layer on the other side of the liquid crystal layer, and then adding first and second electrodes on the first and second orientation layers, respectively. Other structures disclosed herein with respect to any liquid crystal device disclosed herein can also be incorporated into this method using standard fabrication techniques, such as adding polarizer(s), interlayer(s), insulating gas(es), substrates (e.g., first, second, third, and / or fourth glass substrates), and so forth.Various Aspects

[0112] Various aspects of the disclosure will now be discussed with reference to FIGs. 1-8, which illustrate various aspects of the liquid crystal cells (and structures / components thereof), devices (e.g., windows or displays), and methods disclosed herein. The following general description is intended to provide an overview of the disclosure, structures, and methods, and various aspects will be more specifically discussed throughout the disclosure with reference to the non-limiting depictedaspects, all of these aspects being interchangeable with one another within the context of the disclosure.

[0113] FIGs. 1-8 illustrate non-limiting aspects of liquid crystal devices 100a, 100b, 200a, 200b, 200c, 300, 400a, 400b, 500, 600, 700, and 800. As shown in these figures, in conjunction with the rest of the disclosure herein, numerous variations are possible in the structure and configuration of a liquid crystal cell. For example, a liquid crystal device may have a pair of polarizers and a pair of electrodes that sandwich orientation layers and a liquid crystal layer as shown in FIG. 1, or additional glass substrates may be included, as shown in FIGs. 2-3. Moreover, interlayers and / or insulating gas layers may be included, as shown in FIGs. 4 and 8. Moreover, various orientations are contemplated for the nematic liquid crystals, as shown in FIGs. 5-7. In addition, it is explicitly contemplated that any other feature disclosed elsewhere herein, including combining one or more features, can be employed in the FIGs., and vice versa, so as to result in an aspect of the disclosure, such as a liquid crystal device or cell, a method of switching, and / or a method of making.

[0114] FIGs. 1A and IB depict cross-sectional views of liquid crystal devices 100a and 100b according to various aspects of the disclosure. Referring to FIG. 1A, liquid crystal device 100a comprises a liquid crystal cell comprising first 114 and second 115 polarizers having first and second transmission axes (not shown), first 101 and second 105 electrodes, first 102 and second 104 orientation layers disposed between the first 101 and second 105 electrodes, and a liquid crystal layer 103 disposed between the first 102 and second 104 orientation layers, in which the liquid crystal layer 103 is in electrical communication with the first 101 and second 105 electrodes. Although two orientation layers 102 and 104 are depicted, in some aspects only one orientation layer is included (i.e., either first orientation layer 102 or second orientation layer 104). In some aspects, at least one of the first 102 and second 104 orientation layers comprises a grating, or in the situation where only one orientation layer is present, then that orientation layer can comprise a grating. In some aspects, both first 102 and second 104 orientation layers comprise a grating. In some aspects, either or both orientation layers 102 and 104 can be a rubbed polymer, optionally in combination with one of the other orientation layers being a grating. In some aspects, layers 101, 102, 103, 104, 105, 114, and 115 are in contact with one another as depicted in FIG. 1A; however, in some aspects other features can be disposed between any of the layers. In some aspects, other features can be disposed outside of the first 101 and second 105 electrodes, such as substrates, interlayers, insulating gas, adhesives, UV and / or IR protection layers or coatings, and so forth, as indicated by FIGs. 2-4 and other disclosures herein.

[0115] Liquid crystal device 100b in FIG. IB is similar to liquid crystal device 100a in FIG. 1A, except liquid crystal device 100b in FIG. IB also includes a compensation layer 116 disposed between first polarizer 114 and liquid crystal layer 103. Although compensation layer 116 is shown in FIG. IB to be specifically located between first polarizer 114 and first electrode 101, thecompensation layer 116 can be located elsewhere in the liquid crystal device 100b, such as between second polarizer 115 and liquid crystal layer 103, or between second polarizer 115 and second electrode 105. In addition, in some aspects, two or more compensation layers can be included, in which case the two or more compensation layers can be located at any two or more of the aforementioned locations.

[0116] Although not depicted in FIGs. 1A or IB, in some aspects liquid crystal layer 103 comprises a liquid crystal (e.g., a nematic liquid crystal or a bistable liquid crystal), and / or a chiral dopant; at zero applied voltage to the first 101 and second 105 electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state by way of alignment imparted by at least one of the first 102 and second 104 orientation layers; the first stable state is switchable to the second stable state by application of a first stimulus, and the second stable state is switchable to the first stable state by application of a second stimulus; the liquid crystal device 100a or 100b is a liquid crystal cell having a visible light transmittance in the first stable state that is different by at least 20% from visible light transmittance in the second stable state; and the liquid crystal device 100a or 100b is a liquid crystal cell having a haze of less than 5% in both the first stable state and the second stable state. In some aspects, the liquid crystal device 100a or 100b is a liquid crystal cell having a visible light transmittance of at least 45% in the first stable state or the second stable state; the liquid crystal cell has visible light transmittance of less than 45% in the other of the first stable state or the second stable state; and / or the liquid crystal device 100a or 100b is a liquid crystal cell having a haze of less than 3% in both the first stable state and the second stable state. In some aspects, the first 114 and second 115 polarizers are stable at a temperature of at least 100 °C for at least one hour; the liquid crystal device is or comprises a liquid crystal window, and the first 101 and second 105 electrode extend continuously over at last 50% of the area of the liquid crystal window; the first 101 and second 105 electrodes extend continuously within a plane over first and second dimensions wherein each of the first and second dimensions is at least 50 mm; the first 114 and second 115 polarizers are dye-type polarizers; or any combination thereof. In some aspects, the first and second transmission axes are parallel to one another, orthogonal to one another, or have any angle therebetween (e.g. 1, 5, 10, 15, 20, 25, 30, 35, 40, or 45 degrees therebetween, or any range formed from any two of the foregoing numbers).

[0117] FIGs. 2A-2C depict a cross-sectional view of a liquid crystal devices 200a, 200b, and 200c according to various aspects of the disclosure. Features in FIGs. 2A-2C (with format “2XX”) correspond to and can be the same as the corresponding features in FIGs. 1A-1B (with format “1XX”), along with all associated disclosure herein relating to FIGs. 1A-1B and the various possible permutations thereof. In this regard, and to illustrate, first orientation layer 102 in FIGs. 1A-1B corresponds to feature 202 in FIGs. 2A-2C, which is the first orientation layer 202 in FIGs. 2A-2C.As a result, not all features of FIGs. 2A-2C may be repeated given the correspondence with FIG. 1 features.

[0118] FIG. 2A depicts a cross-sectional view of a liquid crystal device according to various aspects of the disclosure. Referring to FIG. 2 A, liquid crystal device 200a comprises a liquid crystal cell comprising first 214 and second 215 polarizers having first and second transmission axes (not shown), first 201 and second 205 electrodes, first 202 and second 204 orientation layers disposed between the first 201 and second 205 electrodes, a liquid crystal layer 203 disposed between the first 202 and second 204 orientation layers, and first 206 and second 207 substrates, in which the first 201 and second 205 electrodes are disposed between the first 206 and second 207 substrates, and the first 206 and second 207 substrates are disposed between the first 214 and second 215 polarizers. In some aspects, one or both of the substrates 206 and 207 are glass substrates. In some aspects, only one of substrates 206 or 207 is present. Although two orientation layers 202 and 204 are depicted, in some aspects only one orientation layer is included (i.e., either first orientation layer 202 or second orientation layer 204). In some aspects, at least one of the first 202 and second 204 orientation layers comprises a grating, or in the situation where only one orientation layer is present, then that orientation layer can comprise a grating. In some aspects, both first 202 and second 204 orientation layers comprise a grating. In some aspects, either or both orientation layers 202 and 204 can be a rubbed polymer, optionally in combination with one of the other orientation layers being a grating. When one of orientation layers 202 and / or 204 is a grating, the grating can be formed into at least one of first 201 and second 205 electrodes. In some aspects, first substrate 206 can be between first electrode 201 and first orientation layer 202. Alternatively or additionally, in some aspects second substrate 207 can be between second electrode 205 and second orientation layer 204. In some aspects, layers 201, 202, 203, 204, 205, 206, 207, 214, and 215 are in contact with one another as depicted in FIG. 2A; however, in some aspects other features can be disposed between any of the layers. In some aspects, other features can be disposed outside of the first 201 and second 205 electrodes, such as substrates, interlayers, insulating gas, adhesives, UV and / or IR protection layers or coatings, and so forth, as indicated by FIGs. 3-4 and other disclosures herein. The liquid crystal device 200a in FIG. 2A can be or comprise a liquid crystal cell having the same transmittance and haze properties as the liquid crystal cell of liquid crystal device 100a or 100b in FIGs. 1A-1B, or as disclosed elsewhere herein.

[0119] Liquid crystal device 200b in FIG. 2B is similar to liquid crystal device 200a in FIG. 2A, except for the location of the first 214 and second 215 polarizers. Specifically, in liquid crystal device 200a in FIG. 2A, the first 214 and second 215 polarizers are located outside of both first 206 and second 207 substrates (i.e., first 206 and second 207 substrates are disposed between the first 214 and second 215 polarizers); in contrast, in liquid crystal device 200b in FIG. 2B, the first 214 and second 215 polarizers are disposed between the first 206 and second 207 substrates. Without wishing to bebound by theory, it is believed that the arrangement depicted in FIG. 2B facilitates the polarizers better withstand higher downstream lamination temperatures since the first 206 and second 207 substrates may at least partially protect the polarizers from the higher temperatures.

[0120] Similarly, liquid crystal device 200c in FIG. 2C is similar to liquid crystal devices 200a and 200b in FIGs. 2A-2B, except for the location of the first 214 and second 215 polarizers. Specifically, in liquid crystal device 200c in FIG. 2C, the first substrate 206 is disposed between the first polarizer 214 and the liquid crystal layer 203, and the second polarizer 215 is disposed between the second substrate 207 and the liquid crystal layer 203.

[0121] For clarity, in some aspects, the first 214 and second 215 polarizers can be located between any of the layers depicted in FIGs. 2A-2C in the same manner as discussed with respect to FIGs. 1A-1C.

[0122] FIG. 3 depicts a cross-sectional view of a liquid crystal device 300 according to various aspects of the disclosure. Features in FIG. 3 (with format “3XX”) correspond to and can be the same as the corresponding features in FIG. 2 (with format “2XX”), along with all associated disclosure herein relating to FIG. 2 and the various possible permutations thereof. In this regard, and to illustrate, first orientation layer 202 in FIG. 2 corresponds to feature 302 in FIG. 3, which is the first orientation layer 302 in FIG. 3. As a result, not all features of FIG. 3 may be repeated given the correspondence with FIG. 2 features. Referring to FIG. 3, liquid crystal device 300 comprises a liquid crystal cell comprising first 314 and second 315 polarizers having first and second transmission axes (not shown), first 301 and second 305 electrodes, first 302 and second 304 orientation layers disposed between the first 301 and second 305 electrodes, a liquid crystal layer 303 disposed between the first 302 and second 304 orientation layers, and first 306 and second 307 substrates, in which the first 301 and second 305 electrodes are disposed between the first 306 and second 307 substrates. The liquid crystal device further comprises third 308 and fourth 309 substrates, in which the first 314 and second 315 polarizers are disposed between the third 308 and fourth 309 substrates, and the first 306 and second 307 substrates are disposed between the first 314 and second 315 polarizers. The first 306 and third 308 substrates are proximal to and optionally bonded to the first polarizer 314, and the second 307 and fourth 309 substrates are proximal to and optionally bonded to the second polarizer 315. In some aspects, any or all of the substrates 306, 307, 308, and 309 independently can be glass substrates. In some aspects, any of substrates 306, 307, 308, and / or 309 can be strengthened glass. In some aspects, substrates 308 and 309 are strengthened glass, and substrates 306 and 307 are made up of glass that is unstrengthened or at least not as strong as substrates 308 and 309. In some aspects, only one of substrates 306 or 308 is present, and / or only one of substrates 307 or 309 is present. Although two orientation layers 302 and 304 are depicted, in some aspects only one orientation layer is included (i.e., either first orientation layer 302 or second orientation layer 304). In some aspects, at least one of the first 302 and second 304 orientation layers comprises a grating, or in the situationwhere only one orientation layer is present, then that orientation layer can comprise a grating. In some aspects, both first 302 and second 304 orientation layers comprise a grating. In some aspects, either or both orientation layers 302 and 304 can be a rubbed polymer, optionally in combination with one of the other orientation layers being a grating. When one of orientation layers 302 and / or 304 is a grating, the grating can be formed into at least one of first 301 and second 305 electrodes. In some aspects, first substrate 306 can be between first electrode 301 and first orientation layer 302. Alternatively or additionally, in some aspects second substrate 307 can be between second electrode 305 and second orientation layer 304. In some aspects, first 314 and second 315 polarizers are located between any of the other layers depicted in FIG. 3 in the same manner as described with respect to FIGs. 1A-1B and 2A-2C. In some aspects, third 308 and / or fourth 309 substrates can have UV and / or IR protection qualities (e.g., UV transmittance of less than 5%), as disclosed elsewhere herein, for example by being Low-E glass and / or by containing a coating with UV and / or IR protection qualities. In some aspects, when the 308 side of the liquid crystal device 300 is facing towards an external environment (e.g., with sunlight), then substrates 306 and / or 308, or any other component, can optionally have UV and / or IR protection qualities and / or coatings, and substrates 307 and / or 309, which face towards the interior of a device comprising the liquid crystal cell 300, or at least face away from the external environment, do not need to have UV and / or IR protection qualities and / or coatings; however, if desired, substrates 307 and / or 309 may also have UV and / or IR protection qualities and / or coatings even if facing towards an interior of a device. Moreover, if desired, none of the substrates or other components have UV and / or IR protection qualities and / or coatings. In some aspects, layers 301, 302, 303, 304, 305, 306, 307, 308, 309, 314, and 315 are in contact with one another as depicted in FIG. 3; however, in some aspects other features can be disposed between any of the layers. In some aspects, other features can be disposed outside of the first 301 and second 305 electrodes, such as substrates, interlayers, insulating gas, adhesives, UV and / or IR protection layers or coatings, and so forth, as indicated by FIGs. 2-4 and other disclosures herein. The liquid crystal device 300 in FIG. 3 can comprise a liquid crystal cell having the same transmittance and haze properties as the corresponding features for liquid crystal cell of liquid crystal device 100a in FIG. 1A or 100b in FIG. IB, or as disclosed elsewhere herein.

[0123] FIGs. 4A-4B depict a cross-sectional view of a liquid crystal devices 400a-400b according to various aspects of the disclosure. Features in FIGs. 4A-4B (with format “4XX”) correspond to and can be the same as the corresponding features in FIG. 3 (with format “3XX”), along with all associated disclosure herein relating to FIG. 3 and the various possible permutations thereof. In this regard, and to illustrate, first orientation layer 302 in FIG. 3 corresponds to feature 402 in FIGs. 4A-4B, which is the first orientation layer 304 in FIGs. 4A-4B. As a result, not all features of FIGs. 4A-4B may be repeated given the correspondence with FIG. 3 features.

[0124] A main difference between FIGs. 4A-4B and FIG. 3 is the inclusion in FIG. 4 of features 410 and 411, each of which can independently be an interlayer and / or an insulating gas. Referring to FIG. 4A, feature 410 is positioned between first polarizer 414 and third substrate 408 (which can comprise glass), and feature 411 is positioned between second polarizer 415 and fourth substrate 409 (which can comprise glass). In some aspects, feature 410 can instead be positioned between third substrate 408 and first substrate 406 (with or without the presence of the first polarizer 414). Alternatively or additionally, feature 411 can instead be positioned between fourth substrate 409 and second substrate 407 (with or without the presence of the second polarizer 415). In any aspect, feature 410 can be a first interlayer, feature 410 can be a first insulating gas, or feature 410 can be made up of two layers: a first interlayer in contact with either first polarizer 414 or third substrate 408 and a cavity with a first insulating gas positioned between the first interlayer and the other of the first polarizer 414 or the third substrate 408 (e.g., see features 410a, 410b, 411a, and 411b in FIG. 4B). The same concept applies to feature 411 with respect to second polarizer 415 and fourth substrate 409. In some aspects, one or both of substrates 408 and 409 are not present, and features 410 and 411 are interlayers positioned on substrates 406 and 407, respectively; optionally in this aspect, one or both of features 410 and 411 additionally include a cavity filled with an insulating gas. In some aspects, the first 414 and second 415 polarizers can be located between any two layers depicted in FIG. 4A, as described elsewhere for FIGs. 1-3.

[0125] FIG. 4B is similar to FIG. 4A, except feature 410 is divided into features 410a / 410b and feature 411 is divided into features 411a / 411b to illustrate what can be meant by the term “an interlayer and / or an insulating gas.” In this regard, feature 410 in FIG. 4A can be an interlayer, an insulating gas, or can be at least two layers (410a / 410b), each of which can independently be an interlayer or an insulating gas. The same concept applies to feature 411 (411a / 411b).

[0126] FIG. 5A depicts a schematic of a liquid crystal device 500 depicting switching a liquid crystal layer from a first stable state 1 to a second stable state 2, according to various aspects of the disclosure. FIG. 5A depicts liquid crystal device 500 having first 514 and second 515 polarizers, first 501 and second 505 electrodes disposed between the first 514 and second 515 polarizers, first 502 and second 504 orientation layers disposed between the first 501 and second 505 electrodes, and a liquid crystal layer 503 disposed between the first 502 and second 504 orientation layers. The liquid crystal layer 503 comprises liquid crystal molecules 513 (e.g., nematic liquid crystals) that is in electrical communication with the first 501 and second 505 electrodes. It is explicitly contemplated that the structures shown in FIG. 5A can optionally include any other feature of FIGs. 2-4, or any other features disclosed herein.

[0127] As shown in FIG. 5A, at zero applied voltage to the first 501 and second 505 electrodes, at least a portion of the liquid crystals 513 are in a first stable state 1 by way of alignment imparted by at least one of the first 502 and second 504 orientation layers. In this first stable state 1, the liquidcrystals 513 are aligned in a homeotropic fashion perpendicular to the plane of the electrodes 501 and 505 and orientation layers 502 and 504. The first stable state 1 is switchable to the second stable state 2 by application of a first stimulus (e.g., 30 V or less in some aspects). In some aspects, the switching comprising applying to the first 501 and second 505 electrodes the first stimulus, the first stimulus optionally comprising at least one first voltage pulse comprising the first polarity to switch the first stable state 1 the second stable state 2 (e.g., the liquid crystal layer 503 is in electrical communication with the first 501 and second 505 electrodes). In some aspects, when in the second stable state 2, a second stimulus can be applied to switch the second stable state 2 to the first stable state 1, the second stimulus optionally comprising applying to the first 501 and second 505 electrodes at least one second voltage pulse comprising the second polarity to switch the second stable state 2 to the first stable state 1. Specifically, FIG. 5A depicts liquid crystals 513 aligned in a second stable state 2 that is parallel to the plane of the electrodes 501 and 505 and orientation layers 502 and 504. In some aspects, to achieve switchability of the liquid crystals to a different orientation at both interfaces with the first 502 and second 504 orientation layers, both the first 502 and second 504 orientation layers are gratings. In some aspects, when the transmission axes of the first 514 and second 515 polarizers are orthogonal to each other, the orientation of liquid crystals 513 in the first stable state 1 results in a lower transmittance in the first stable state 1 than the second stable state 2 (i.e., the first stable state 1 is a “dark” state and the second stable state 2 is a “clear” state). However, in some aspects, when the transmission axes of the first 514 and second 515 polarizers are parallel to each other, the orientation of liquid crystals 513 in the first stable state 1 results in a higher transmittance in the first stable state1 than the second stable state 2 (i.e., the first stable state 1 is a “clear” state and the second stable state2 is a “dark” state). In some aspects, the transmission axis of at least one of the first 514 and second 515 polarizers makes an angle of about 45 degrees, or between 40 and 50 degrees, relative to the planar orientation of at least one orientation layer. In some aspects, when a grating is employed, the groove direction of the grating makes an angle of about 45 degrees, or between 40 and 50 degrees, relative to the planar orientation of at least one orientation layer.

[0128] FIG. 5B is similar to FIG. 5A, except only liquid crystals at or near the interface with second orientation layer 504 are switchable to a different orientation (e.g., the second orientation layer 504 may be a grating and the first orientation layer 502 may be a rubbed polymer). In this regard, liquid crystals 513 are aligned in a second stable state 2, in which liquid crystals 513 closer to second orientation layer 504 are aligned in a more parallel fashion (to the plane of the electrodes 501 and 505 and orientation layers 502 and 504) than liquid crystals 513 closer to the first orientation layer 502. The liquid crystals 513 near first orientation layer 502 are in a homeotropic or near homeotropic alignment in both the first 1 and second 2 stable states. In this aspect, there is an alignment gradient from second orientation layer 504 to first orientation layer 502. All other disclosures with respect to FIG. 5A (and all other disclosures elsewhere herein) are equally applicable to FIG. 5B.

[0129] FIG. 6 is similar to FIG. 5B, except that the orientation in the first stable state 1 near the first orientation layer 602 is not completely homeotropic. FIG. 6 depicts liquid crystal cell 600 having first 614 and second 615 polarizers, first 601 and second 605 electrodes disposed between the first 614 and second 615 polarizers, first 602 and second 604 orientation layers disposed between the first 601 and second 605 electrodes, and a liquid crystal layer 603 comprising liquid crystals 613 disposed between the first 602 and second 604 orientation layers. It is explicitly contemplated that the structures shown in FIG. 6 can optionally include any other feature of FIGs. 2-5, or any other features disclosed herein.

[0130] As shown in FIG. 6, at zero applied voltage to the first 601 and second 605 electrodes, at least a portion of the liquid crystals 613 are in a first stable state 1 by way of alignment imparted by at least one of the first 602 and second 604 orientation layers. In this first stable state 1, the liquid crystals 613 near second orientation layer 604 are aligned in a homeotropic fashion perpendicular to the plane of the electrodes 601 and 605 and orientation layers 602 and 604, whereas the liquid crystals 613 near first orientation layer 602 are not completely perpendicular. This alignment still allows sufficiently high transmittance of visible light through the liquid crystal cell in one of the first stable state 1 and the second stable state 2. The first stable state 1 is switchable to the second stable state 2 (and vice versa) by application of a first stimulus. As shown in FIG. 6, in the second stable state 2, liquid crystals 613 are aligned in a second stable state 2 that is parallel to the plane of the electrodes 601 and 605 at or near second orientation 604, which changes the transmittance of visible light through the structure. In some aspects, to achieve this type of switchability of the liquid crystals in which only those at or near orientation layer 604 are switchable, as shown in FIG. 6, only the second604 orientation layer is a grating, whereas first orientation layer 602 either is not present or is a rubbed polymer.

[0131] In some aspects, the switching in FIG. 6 comprises applying to the first 601 and second605 electrodes the first stimulus, the first stimulus optionally comprising at least one first voltage pulse comprising the first polarity to switch the first stable state 1 the second stable state 2 (e.g., the liquid crystal layer 603 is in electrical communication with the first 601 and second 605 electrodes). In some aspects, when in the second stable state 2, a second stimulus can be applied to switch the second stable state 2 to the first stable state 1, the second stimulus optionally comprising applying to the first 601 and second 605 electrodes at least one second voltage pulse comprising the second polarity to switch the second stable state 2 to the first stable state 1.

[0132] FIG. 7A depicts a schematic of a liquid crystal cell 700 depicting switching a liquid crystal layer 703 possessing chirality from a first stable state 1 to a second stable state 2, according to various aspects of the disclosure. FIG. 7A depicts liquid crystal cell 700 having first 714 and second 715 polarizers, first 701 and second 705 electrodes disposed between the first 714 and second 715 polarizers, first 702 and second 704 orientation layers disposed between the first 701 and second 705electrodes, and a liquid crystal layer 703 disposed between the first 702 and second 704 orientation layers. The liquid crystal layer 703 comprises liquid crystal molecules 713 (e.g., nematic liquid crystals) and a chiral dopant (not shown). It is explicitly contemplated that the structures shown in FIG. 7A can optionally include any other feature of FIGs. 2-6, or any other features disclosed herein.

[0133] As shown in FIG. 7A, at zero applied voltage to the first 701 and second 705 electrodes, at least a portion of the liquid crystals 713 are in a first stable state 1 by way of alignment imparted by at least one of the first 702 and second 704 orientation layers. Inclusion of a chiral dopant (not shown) imparts a rotation to the liquid crystal about an axis when in at least one of the first stable state 1 and the second stable state 2, as disclosed elsewhere herein. This is depicted visually in the second stable state 2 of FIG. 7A, which shows the molecules 713 rotating about an axis perpendicular to the plane of the first 702 and second 704 orientation layers (while rotation may also be present about the same axis in the first stable state 1 of FIG. 7A, this is not visually depicted). Rotation may also be present in the first stable state 1 of FIG. 7A (not depicted), though there may be no appreciable effect on visible light transmittance. However, in the second stable state 2 of FIG. 7A, visible light transmittance is changed relative to the first stable state 1. In the first stable state 1, the liquid crystals 713 are aligned in a homeotropic fashion perpendicular to the plane of the electrodes 701 and 705 and orientation layers 702 and 704. This alignment allows different transmittance of visible light through the liquid crystal cell in the first stable state 1 than in the second stable state 2 (and, as discussed with respect to FIG. 5, can depend on whether the transmission axes of the first and second polarizers is orthogonal or parallel). In the second stable state 2, liquid crystals 713 are aligned parallel to the plane of the electrodes 701 and 705, and orientation layers 702 and 704, and the liquid crystals 713 rotate about an axis, as described above. In some aspects, to achieve switchability of the liquid crystals to a different orientation at both interfaces with the first 702 and second 704 orientation layers, as shown in FIG. 7A, both the first 702 and second 704 orientation layers are gratings.

[0134] In some aspects of FIG. 7A, the switching comprises applying to the first 701 and second 705 electrodes a first stimulus to switch the first stable state 1 to a second stable state 2. In some aspects, the first stimulus optionally comprises at least one first voltage pulse comprising the first polarity to switch the first stable state 1 to a second stable state 2 (e.g., the liquid crystal layer 703 is in electrical communication with the first 701 and second 705 electrodes). In some aspects, when in the second stable state 2, a second stimulus can be applied to switch the second stable state 2 to the first stable state 1, the second stimulus optionally comprising applying to the first 701 and second 705 electrodes at least one second voltage pulse comprising the second polarity to switch the second stable state 2 to the first stable state 1.

[0135] FIG. 7B is similar to FIG. 7A, except that the liquid crystal orientation in the second stable state 2 near the first orientation layer 702 is not switchable, but rather remains in a generally homeotropic state at or near the first orientation layer 702. To achieve this type of switchabilitydepicted in FIG. 7B, in some aspects, first orientation layer 702 is either not present or is a rubbed polymer, whereas second orientation layer 704 is a grating. It is explicitly contemplated that the structures shown in FIG. 7B can optionally include any other feature of FIGs. 2-6 or 7A, or any other features disclosed herein.

[0136] FIG. 7C is similar to FIG. 7B, except that inclusion of a chiral dopant (not shown) imparts a rotation to the liquid crystal about an axis when in both the first stable state 1 and the second stable state 2. This is depicted visually in both the first stable state 1, which shows molecules 713 rotating about a horizontal axis that is co-planar with the electrodes 701 / 705, and also in the second stable state 2 of FIG. 7A, which shows the molecules 713 rotating about a vertical axis perpendicular to electrodes 701 / 705. In both the first 1 and second 2 stable states, the first orientation layer 701 imparts a planar arrangement of molecules 713 but is not switchable to another stable state, whereas second orientation layer 704 imparts a homeotropic alignment to molecules 713 in the first stable state 1 that is switchable to a planar arrangement in second stable state 2.

[0137] In an alternative to FIG. 5A, in the second stable state 2, the liquid crystal molecules near first orientation layer 502 can be at a given angle, such as at about 90 degrees relative to those near second orientation layer 504. This type of angle is achievable by employing gratings at first orientation layer 502 and second orientation layer 504 that are arranged at an angle instead of parallel to each other. In this type of configuration, the liquid crystal molecules rotate from one orientation layer to the other orientation layer through the cell thickness. The second stable state 2 absorbs a different amount of visible light than the first stable state 1, thus improving the contrast of the liquid crystal device 500. This configuration may not have any chiral dopant, or may have a small amount of chiral dopant, as disclosed elsewhere herein. Similar types of alternative configurations are also applicable to the second stable state 2 in FIG. 6 and the second stable state 2 in FIG. 7A.

[0138] FIG. 8A depicts a schematic cut-away side view of an insulated glass unit (IGU) incorporating a liquid crystal cell, according to various aspects of the disclosure. In particular, FIG. 8A depicts a liquid crystal device 800, in which the liquid crystal device 800 is an insulated glass unit (IGU). The IGU comprises liquid crystal cell 801. Although not shown, liquid crystal cell 801 comprises first and second polarizers; first and second electrodes (optionally disposed between the first and second polarizers, or at least one of the first and second polarizers can be disposed between the first and second electrodes); first and second orientation layers disposed between the first and second electrodes; a liquid crystal layer disposed between the first and second orientation layers; and first and second glass substrates, wherein the first and second electrodes are disposed between the first and second glass substrates. Optionally, the liquid crystal cell is configured as a liquid crystal panel, which incorporates at least one, optionally two additional glass panes (not shown) on either side (major surface) of the liquid crystal cell 801. The additional panes may comprise tempered glass, e.g., sodalime glass, such that additional structural rigidity and / or support is provided to the liquid crystalcell. The first panel pane is adhered to the first side of the liquid crystal cell via a first interlayer (not shown) and (if used) the second panel pane is adhered to the second side of the liquid crystal cell via a second interlayer (not shown). The IGU has a third glass substrate 804 and a first insulating gas disposed (in cavity 803) between the first glass substrate (or first panel pane) (not shown, but is on right side of liquid crystal cell 801) and third glass substrate 804. Spacers 802 are included to facilitate offsetting the third glass substrate 804 from liquid crystal cell 801, which also forms a cavity 803 for containing an insulating glass. Although two spacers 802 are depicted, in some aspects only one spacer 802 is included, or in some aspects three, four, five, or six or more spacers are included. In some aspects, the IGU can additionally include a seal, which maintains spacer integrity, prevents moisture from infiltrating into insulating gas cavities 803, and / or prevents leakage of the insulating gas from cavities 803. The IGU can be incorporated into a window, as shown and described with respect to FIG. 8B.

[0139] FIG. 8B depicts a schematic cut-away side view of a liquid crystal window having a triple pane insulated glass unit (IGU) with a liquid crystal cell as the center pane, according to various aspects of the disclosure. In particular, FIG. 8B depicts a liquid crystal device 800 comprising a liquid crystal window, the liquid crystal window comprising: a liquid crystal cell 801. Although not shown, liquid crystal cell 801 comprises first and second polarizers; first and second electrodes (optionally disposed between the first and second polarizers, or at least one of the first and second polarizers can be disposed between the first and second electrodes); first and second orientation layers disposed between the first and second electrodes; a liquid crystal layer disposed between the first and second orientation layers; and first and second glass substrates, wherein the first and second electrodes are disposed between the first and second glass substrates. Uiquid crystal device 800 has third and fourth glass substrates 804; wherein the first and second glass substrates (not shown) are disposed between the third and fourth glass substrates 804, the first and third glass substrates being proximal to one another and the second and fourth glass substrates being proximal to one another. A first insulating gas is disposed between the first glass substrate (not shown, but is the left side of liquid crystal cell 801) and third glass substrate 804. In some aspects, the first polarizer is disposed between the first and third glass substrates, in which the first insulating gas is either between the first polarizer and the first substrate or the first polarizer and the third substrate. A second insulating gas is disposed between the second glass substrate (not shown, but is the right side of liquid crystal cell 801) and fourth glass substrate 804. In some aspects, the second polarizer is disposed between the second and fourth glass substrates, in which the first insulating gas is either between the second polarizer and the second substrate or the second polarizer and the fourth substrate. A frame 805 is attached to minor surfaces of the first, second, third, and fourth glass substrates; however, although two frames 805 are shown, in some aspects only one frame is included, either on the top or bottom. Spacers 802 are include to facilitate offsetting the third and fourth glass substrates 804 from liquid crystal cell 801, which alsoforms cavities 803 for containing an insulating glass. Although four spacers 802 are depicted, in some aspects other amounts of spacers 802 are contemplated as described with respect to FIG. 8A and elsewhere herein. For example, in some aspects, only one spacer 802 is included on the left side of liquid crystal device 800 (or three or more can be included), and / or only one spacer 802 is included on the right of liquid crystal device 800 (or three or more can be included). In some aspects, the window can additionally include a seal, which maintains spacer integrity, prevents moisture from infiltrating into insulating gas cavities 803, and / or prevents leakage of the insulating gas from cavities 803. The combination of liquid crystal cell 801, one or more spacers 802, and one of glass substrates 804 defines an insulated glass unit (IGU), as discussed with respect to FIG. 8A. As set forth above in FIG. 8A, the liquid crystal cell 801 may optionally be configured as a panel, with a first panel pane adhered to the first side of the liquid crystal cell via a first interlayer (not shown) and a second panel pane configured to a second side of the liquid crystal cell via a second interlayer.

[0140] Various aspects are contemplated herein, several of which are set forth in the paragraphs below. It is explicitly contemplated that any aspect or portion thereof can be combined to form a combination.

[0141] Aspect 1: A liquid crystal device, comprising: a liquid crystal cell, comprising: first and second glass substrates; first and second polarizers having first and second transmission axes, respectively; first and second electrodes; first and second orientation layers disposed between the first and second electrodes; and a liquid crystal layer disposed between the first and second orientation layers, the liquid crystal layer in electrical communication with the first and second electrodes; wherein: the first and second polarizers are stable at a temperature of at least 100 °C for at least one hour; the liquid crystal layer comprises a nematic liquid crystal; at zero applied voltage to the first and second electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state by way of alignment imparted by at least one of the first and second orientation layers;the first stable state is switchable to the second stable state by application of a first stimulus, and the second stable state is switchable to the first stable state by application of a second stimulus; the liquid crystal cell has visible light transmittance in the first stable state that is different by at least 20% from visible light transmittance in the second stable state; and the liquid crystal cell has haze of less than 5% in both the first stable state and the second stable state.

[0142] Aspect 2: The liquid crystal device of any preceding aspect, wherein the first and second polarizers are disposed between the first and second glass substrates.

[0143] Aspect 3: The liquid crystal device of any preceding aspect, wherein the liquid crystal device is or comprises a liquid crystal window, and the first and second electrode extend continuously over at least 50% of the area of the liquid crystal window.

[0144] Aspect 4: A liquid crystal device, comprising: a liquid crystal cell, comprising: first and second glass substrates; first and second polarizers having first and second transmission axes, respectively; first and second electrodes; first and second orientation layers disposed between the first and second electrodes; and a liquid crystal layer disposed between the first and second orientation layers, the liquid crystal layer in electrical communication with the first and second electrodes; wherein: the first and second polarizers are disposed between the first and second glass substrates; the liquid crystal layer comprises a nematic liquid crystal; at zero applied voltage to the first and second electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state by way of alignment imparted by at least one of the first and second orientation layers;the first stable state is switchable to the second stable state by application of a first stimulus, and the second stable state is switchable to the first stable state by application of a second stimulus; the liquid crystal cell has visible light transmittance in the first stable state that is different by at least 20% from visible light transmittance in the second stable state; and the liquid crystal cell has haze of less than 5% in both the first stable state and the second stable state.

[0145] Aspect 5: A liquid crystal device, comprising: a liquid crystal cell, comprising: first and second glass substrates; first and second polarizers having first and second transmission axes, respectively; first and second electrodes; first and second orientation layers disposed between the first and second electrodes; and a liquid crystal layer disposed between the first and second orientation layers, the liquid crystal layer in electrical communication with the first and second electrodes; wherein: the liquid crystal device is or comprises a liquid crystal window, and the first and second electrode extend continuously over at least 50% of the area of the liquid crystal window; the liquid crystal layer comprises a nematic liquid crystal; at zero applied voltage to the first and second electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state by way of alignment imparted by at least one of the first and second orientation layers; the first stable state is switchable to the second stable state by application of a first stimulus, and the second stable state is switchable to the first stable state by application of a second stimulus; the liquid crystal cell has visible light transmittance in the first stable state that is different by at least 20% from visible light transmittance in the second stable state; and the liquid crystal cell has haze of less than 5% in both the first stable state and the second stable state.

[0146] Aspect 6: The liquid crystal device of any preceding aspect, wherein the first and second electrodes extend continuously within a plane over first and second dimensions; wherein each of the first and second dimensions is at least 50 mm.

[0147] Aspect 7: The liquid crystal device of any preceding aspect, wherein the liquid crystal cell has visible light transmittance of at least 45% in the first stable state or the second stable state; and the liquid crystal cell has visible light transmittance of less than 45% in the other of the first stable state or the second stable state.

[0148] Aspect 8: The liquid crystal device of any preceding aspect, wherein the liquid crystal cell has haze of less than 3% in both the first stable state and the second stable state.

[0149] Aspect 9: The liquid crystal device of any preceding aspect, wherein the nematic liquid crystal is a bistable liquid crystal.

[0150] Aspect 10: The liquid crystal device of any preceding aspect, wherein, in at least one of the first stable state and the second stable state, the nematic liquid crystal is aligned in at least one of a continuous texture and a defect texture.

[0151] Aspect 11 : The liquid crystal device of any preceding aspect, further comprising a chiral dopant that imparts a rotation to the nematic liquid crystal about an axis when in at least one of the first stable state and the second stable state; optionally wherein a total rotation angle of the nematic liquid crystal from the first orientation layer to the second orientation layer is from 45 degrees to 3600 degrees.

[0152] Aspect 12: The liquid crystal device of any preceding aspect, wherein: the first stimulus comprises at least one first voltage pulse comprising a first polarity; the second stimulus comprises at least one second voltage pulse comprising a second polarity; and the first polarity and the second polarity are opposite in sign.

[0153] Aspect 13: The liquid crystal device of aspect 12, or any preceding aspect: wherein the first stimulus further comprises, prior to the at least one first voltage pulse comprising the first polarity, at least one first bipolar voltage pulse sufficient to lower a first magnitude of the at least one first voltage pulse necessary to switch the first stable state to the second stable state; and / or wherein the second stimulus further comprises, prior to the at least one second voltage pulse comprising the second polarity, at least one second bipolar voltage pulse sufficient to lower a second magnitude of the at least one second voltage pulse necessary to switch the second stable state to the first stable state.

[0154] Aspect 14: The liquid crystal device of any preceding aspect, wherein the first and second polarizers are dye-type polarizers.

[0155] Aspect 15: The liquid crystal device of any preceding aspect, wherein at least one of the first and second orientation layers comprises a grating.

[0156] Aspect 16: The liquid crystal device of any preceding aspect, wherein the first and second electrodes are disposed between the first and second glass substrates; optionally wherein at least one of the first and second orientation layers comprises a grating formed into at least one of the first and second electrodes.

[0157] Aspect 17: The liquid crystal device of any preceding aspect, further comprising: third and fourth glass substrates; wherein the first and second glass substrates are disposed between the third and fourth glass substrates, the first and third glass substrates being proximal to and optionally bonded to one another and the second and fourth glass substrates being proximal to and optionally bonded to one another; optionally wherein at least one of the third glass substrate and fourth glass substrate has a UV transmittance of less than 5%.

[0158] Aspect 18: The liquid crystal device of aspect 17, or any preceding aspect, wherein the third and / or fourth glass substrates comprise thermally strengthened glass, chemically strengthened glass, tempered glass, or any combination thereof.

[0159] Aspect 19: The liquid crystal device of aspect 17 or aspect 18, or any preceding aspect, further comprising:(a) a first interlayer and / or a first insulating gas disposed between the first and third glass substrates; and / or(b) a second interlayer and / or a second insulating gas disposed between the second and fourth glass substrates; optionally wherein the first and / or second interlayers comprise polyvinyl butyral (PVB), ethylene -vinyl acetate (EVA), polylactic acid, polyurethanes, ionoplast polymer, or any combination thereof; optionally wherein at least one of the first interlayer and second interlayer has a UV transmittance of less than 5%.

[0160] Aspect 20: The liquid crystal device of any preceding aspect, wherein at least one of the first stable state and the second stable state comprises nematic liquid crystals aligned perpendicular or parallel to at least one of the first orientation layer, the second orientation layer, the first electrode, and the second electrode.

[0161] Aspect 21: The liquid crystal device of any preceding aspect,wherein the liquid crystal device is a component of a window or a display.

[0162] Aspect 22: The liquid crystal device of any preceding aspect, further comprising a compensation film between at least one of (1) the first polarizer and the liquid crystal layer, and (2) the second polarizer and the liquid crystal layer.

[0163] Aspect 23: The liquid crystal device of any preceding aspect, wherein: the first and second transmission axes are orthogonal; at least one of the first and second orientation layers is a grating having a grating direction; and the grating direction is 40-50 degrees relative to the first or second transmission axis.

[0164] Aspect 24: The liquid crystal device of any preceding aspect, wherein: the first and second transmission axes are parallel; at least one of the first and second orientation layers is a grating having a grating direction; and the grating direction is 40-50 degrees relative to the first or second transmission axis.

[0165] Aspect 25: The liquid crystal device of any preceding aspect, the first and second electrodes are disposed between the first and second glass substrates.

[0166] Aspect 26: A method for switching the liquid crystal device of any preceding aspect, the method comprising: when in the first stable state, applying to the first and second electrodes a first stimulus comprising at least one first voltage pulse comprising the first polarity to switch the first stable state to the second stable state; and / or when in the second stable state, applying to the first and second electrodes a second stimulus comprising at least one second voltage pulse comprising the second polarity to switch the second stable state to the first stable state.

[0167] Aspect 27: The method of aspect 26, or any preceding aspect, wherein at least one of the first and second voltage pulses is 30 V or less.

[0168] Aspect 28: The method of aspect 26 or aspect 27, or any preceding aspect, wherein the liquid crystal device is in the first stable state, and the first stimulus further comprises, prior to applying the at least one first voltage pulse comprising the first polarity, applying at least one first bipolar voltage pulse sufficient to lower a first magnitude of the at least one first voltage pulse necessary to switch the first stable state to the second stable state.

[0169] Aspect 29: The method of any one of aspects 26-28, or any preceding aspect, wherein the second stimulus further comprises, prior to applying the at least one second voltage pulse comprising the second polarity, applying at least one second bipolarvoltage pulse sufficient to lower a second magnitude of the at least one second voltage pulse necessary to switch the second stable state to the first stable state.

[0170] Aspect 30: A method of making the liquid crystal device of any one of aspects 1-25, or any preceding aspect, the method comprising, in any order: providing the first and second glass substrates, the first and second polarizers, the first and second electrodes, the first and second orientation layers, and the liquid crystal layer; disposing the first and second orientation layers between the first and second electrodes; and positioning the liquid crystal layer between the first and second orientation layers.

[0171] Aspect 31 : A liquid crystal device comprising a liquid crystal window, the liquid crystal window comprising: a liquid crystal cell, comprising: first and second polarizers having first and second transmission axes, respectively; first and second electrodes; first and second orientation layers disposed between the first and second electrodes, the liquid crystal layer in electrical communication with the first and second electrodes; a liquid crystal layer disposed between the first and second orientation layers; and first and second glass substrates, wherein the first and second electrodes and the first and second polarizers are disposed between the first and second glass substrates; third and fourth glass substrates; wherein the first and second glass substrates are disposed between the third and fourth glass substrates, the first and third glass substrates being proximal to one another and the second and fourth glass substrates being proximal to one another; a first insulating gas disposed between the first and third glass substrates; a second insulating gas disposed between the second and fourth glass substrates; and a frame attached to minor surfaces of the first, second, third, and fourth glass substrates; wherein: the liquid crystal layer comprises a nematic liquid crystal; at zero applied voltage to the first and second electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state by way of alignment imparted by at least one of the first and second orientation layers;the first stable state is switchable to the second stable state by application of a first stimulus, and the second stable state is switchable to the first stable state by application of a second stimulus; the liquid crystal cell has visible light transmittance in the first stable state that is different by at least 20% from visible light transmittance in the second stable state; and the liquid crystal cell has haze of less than 5% in both the first stable state and the second stable state.

[0172] Aspect 32: A liquid crystal device comprising an insulated glass unit, the insulated glass unit comprising: a liquid crystal cell, comprising: first and second polarizers having first and second transmission axes, respectively; first and second electrodes; first and second orientation layers disposed between the first and second electrodes, the liquid crystal layer in electrical communication with the first and second electrodes; a liquid crystal layer disposed between the first and second orientation layers; and first and second glass substrates, wherein the first and second electrodes and the first and second polarizers are disposed between the first and second glass substrates; a third glass substrate; and a first insulating gas disposed between the first and third glass substrates; wherein: the liquid crystal layer comprises a nematic liquid crystal; at zero applied voltage to the first and second electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state by way of alignment imparted by at least one of the first and second orientation layers; the first stable state is switchable to the second stable state by application of a first stimulus, and the second stable state is switchable to the first stable state by application of a second stimulus; the liquid crystal cell has visible light transmittance in the first stable state that is different by at least 20% from visible light transmittance in the second stable state; and the liquid crystal cell has haze of less than 5% in both the first stable state and the second stable state.

[0173] Aspect 33: A combination of any two or more preceding aspects or any portion(s) thereof.EXAMPLES

[0174] The following examples illustrate non-limiting aspects of the disclosure and are not intended to be limiting on the scope of the disclosure or claims.

[0175] Various examples of liquid crystal device structure and results are summarized below inTable 1.Table 1

[0176] Additional various examples of liquid crystal device structure and results are summarized below in Table 2. This example generally relates to the structures disclosed herein, including to FIG. 7C. Generally, the transmission axis of the first polarizer and the transmission axis of the second polarizer can be either parallel or orthogonal to each other. The transmission axis of the first polarizer is either parallel or orthogonal to the planar orientation of the first orientation layer. The groove direction of the grating (second orientation layer) is orthogonal to the planar orientation of the first orientation layer.Table 2

[0177] Further various examples of liquid crystal device structure and results are contemplated, including certain specific variations on the structures depicted in Table 2. For example, Example 3.1 is the same as Example 2.1 except there is a compensation film between the second polarizer and the liquid crystal layer, or between the first polarizer and the liquid crystal layer. The compensation film can be a discotic liquid crystal polymer, with its optic axis tilting in the thickness direction. The compensation film improves the viewing angle characteristic of the dark state shown in first stable state 1 of FIG. 7C. Example 3.2 is the same as Example 2.2 except there is a compensation film between the second polarizer and the liquid crystal layer, or between the first polarizer and the liquid crystal layer. The compensation film can be a discotic liquid crystal polymer, with its optic axis tilting in the thickness direction. The compensation film improves the viewing angle characteristic of the dark state shown in first stable state 1 of FIG. 7C.

[0178] Many variations based on the Examples set forth above are contemplated.

[0179] It will be appreciated that the various disclosed aspects or embodiments may involve particular features, elements or steps that are described in connection with that particular aspect or embodiment. It will also be appreciated that a particular feature, element, or step, although described in relation to one particular aspect or embodiment, may be interchanged or combined with alternate aspects or embodiments in various non-illustrated combinations or permutations.

[0180] As used herein, the term “and / or,” when used in a list of two or more items, means that any one of the listed items can be employed by itself, or any combination of two or more of the listed items can be employed. For example, if a composition is described as containing components A, B, and / or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination.

[0181] While various features, elements, or steps of particular aspects or embodiments may be disclosed using the transitional phrase “comprising,” it is to be understood that alternative aspects or embodiments, including those that may be described using the transitional phrases “consisting of’ or “consisting essentially of,” are implied. Thus, for example, implied alternative aspects or embodiments to a device that comprises A+B+C include aspects or embodiments where a device consists of A+B+C and aspects or embodiments where a device consists essentially of A+B+C.

[0182] References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below,” “first,” “second,” etc.) are merely used to describe the orientation of various elements in the FIGURES. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure. Moreover, these relational terms are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions.

[0183] As utilized herein, the terms “approximately,” “about,” “substantially”, and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the invention as recited in the appended claims.

[0184] As utilized herein, “optional,” “optionally,” or the like are intended to mean that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where the event or circumstance occurs and instances where it does not occur. As used herein, the indefinite articles “a,” “an,” and the corresponding definite article “the” mean “at least one” or “one or more,” unless otherwise specified. It also is understood that the various features disclosed in the specification and the drawings can be used in any and all combinations.

[0185] With respect to the use of substantially any plural and / or singular terms herein, those having skill in the art can translate from the plural to the singular and / or from the singular to the plural as is appropriate to the context and / or application. The various singular / plural permutations may be expressly set forth herein for the sake of clarity.

[0186] Unless otherwise specified, all compositions are expressed in terms of as-batched weight percent (wt.%). As will be understood by those having ordinary skill in the art, various melt constituents (e.g., silicon, alkali- or alkaline-based, boron, etc.) may be subject to different levels of volatilization (e.g., as a function of vapor pressure, melt time and / or melt temperature) during melting of the constituents. As such, the as-batched weight percent values used in relation to such constituentsare intended to encompass values within ±0.5 wt.% of these constituents in final, as-melted articles. With the forgoing in mind, substantial compositional equivalence between final articles and as- batched compositions is expected.

[0187] It will be apparent to those ordinarily skilled in the art that various modifications and variations can be made to the present disclosure without departing from the spirit and scope of the disclosure. Since modifications combinations, sub-combinations, and variations of the disclosed embodiments incorporating the spirit and substance of the disclosure may occur to persons ordinarily skilled in the art, the disclosure should be construed to include everything within the scope of the appended claims and their equivalents.

Claims

WHAT IS CLAIMED IS:

1. A liquid crystal device, comprising: a liquid crystal cell, comprising: first and second glass substrates; first and second polarizers having first and second transmission axes, respectively; first and second electrodes; first and second orientation layers disposed between the first and second electrodes; and a liquid crystal layer disposed between the first and second orientation layers, the liquid crystal layer in electrical communication with the first and second electrodes; wherein: the first and second polarizers are stable at a temperature of at least 100 °C for at least one hour; the liquid crystal layer comprises a nematic liquid crystal; at zero applied voltage to the first and second electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state by way of alignment imparted by at least one of the first and second orientation layers; the first stable state is switchable to the second stable state by application of a first stimulus, and the second stable state is switchable to the first stable state by application of a second stimulus; the liquid crystal cell has visible light transmittance in the first stable state that is different by at least 20% from visible light transmittance in the second stable state; and the liquid crystal cell has haze of less than 5% in both the first stable state and the second stable state.

2. The liquid crystal device of any preceding claim, wherein the first and second polarizers are disposed between the first and second glass substrates.

3. The liquid crystal device of any preceding claim,wherein the liquid crystal device is or comprises a liquid crystal window, and the first and second electrode extend continuously over at least 50% of the area of the liquid crystal window.

4. A liquid crystal device, comprising: a liquid crystal cell, comprising: first and second glass substrates; first and second polarizers having first and second transmission axes, respectively; first and second electrodes; first and second orientation layers disposed between the first and second electrodes; and a liquid crystal layer disposed between the first and second orientation layers, the liquid crystal layer in electrical communication with the first and second electrodes; wherein: the first and second polarizers are disposed between the first and second glass substrates; the liquid crystal layer comprises a nematic liquid crystal; at zero applied voltage to the first and second electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state by way of alignment imparted by at least one of the first and second orientation layers; the first stable state is switchable to the second stable state by application of a first stimulus, and the second stable state is switchable to the first stable state by application of a second stimulus; the liquid crystal cell has visible light transmittance in the first stable state that is different by at least 20% from visible light transmittance in the second stable state; and the liquid crystal cell has haze of less than 5% in both the first stable state and the second stable state.

5. A liquid crystal device, comprising: a liquid crystal cell, comprising: first and second glass substrates; first and second polarizers having first and second transmission axes, respectively; first and second electrodes;first and second orientation layers disposed between the first and second electrodes; and a liquid crystal layer disposed between the first and second orientation layers, the liquid crystal layer in electrical communication with the first and second electrodes; wherein: the liquid crystal device is or comprises a liquid crystal window, and the first and second electrode extend continuously over at least 50% of the area of the liquid crystal window; the liquid crystal layer comprises a nematic liquid crystal; at zero applied voltage to the first and second electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state by way of alignment imparted by at least one of the first and second orientation layers; the first stable state is switchable to the second stable state by application of a first stimulus, and the second stable state is switchable to the first stable state by application of a second stimulus; the liquid crystal cell has visible light transmittance in the first stable state that is different by at least 20% from visible light transmittance in the second stable state; and the liquid crystal cell has haze of less than 5% in both the first stable state and the second stable state.

6. The liquid crystal device of any preceding claim, wherein the first and second electrodes extend continuously within a plane over first and second dimensions; wherein each of the first and second dimensions is at least 50 mm.

7. The liquid crystal device of any preceding claim, wherein the liquid crystal cell has visible light transmittance of at least 45% in the first stable state or the second stable state; and the liquid crystal cell has visible light transmittance of less than 45% in the other of the first stable state or the second stable state.

8. The liquid crystal device of any preceding claim, wherein the liquid crystal cell has haze of less than 3% in both the first stable state and the second stable state.

9. The liquid crystal device of any preceding claim,wherein the nematic liquid crystal is a bistable liquid crystal.

10. The liquid crystal device of any preceding claim, wherein, in at least one of the first stable state and the second stable state, the nematic liquid crystal is aligned in at least one of a continuous texture and a defect texture.

11. The liquid crystal device of any preceding claim, further comprising a chiral dopant that imparts a rotation to the nematic liquid crystal about an axis when in at least one of the first stable state and the second stable state; optionally wherein a total rotation angle of the nematic liquid crystal from the first orientation layer to the second orientation layer is from 45 degrees to 3600 degrees.

12. The liquid crystal device of any preceding claim, wherein: the first stimulus comprises at least one first voltage pulse comprising a first polarity; the second stimulus comprises at least one second voltage pulse comprising a second polarity; and the first polarity and the second polarity are opposite in sign.

13. The liquid crystal device of claim 12, wherein the first stimulus further comprises, prior to the at least one first voltage pulse comprising the first polarity, at least one first bipolar voltage pulse sufficient to lower a first magnitude of the at least one first voltage pulse necessary to switch the first stable state to the second stable state; and / or wherein the second stimulus further comprises, prior to the at least one second voltage pulse comprising the second polarity, at least one second bipolar voltage pulse sufficient to lower a second magnitude of the at least one second voltage pulse necessary to switch the second stable state to the first stable state.

14. The liquid crystal device of any preceding claim, wherein the first and second polarizers are dye-type polarizers.

15. The liquid crystal device of any preceding claim, wherein at least one of the first and second orientation layers comprises a grating.

16. The liquid crystal device of any preceding claim, wherein the first and second electrodes are disposed between the first and second glass substrates; optionally wherein at least one of the first and second orientation layers comprises a grating formed into at least one of the first and second electrodes.

17. The liquid crystal device of any preceding claim, further comprising:third and fourth glass substrates; wherein the first and second glass substrates are disposed between the third and fourth glass substrates, the first and third glass substrates being proximal to and optionally bonded to one another and the second and fourth glass substrates being proximal to and optionally bonded to one another; optionally wherein at least one of the third glass substrate and fourth glass substrate has a UV transmittance of less than 5%.

18. The liquid crystal device of claim 17, wherein the third and / or fourth glass substrates comprise thermally strengthened glass, chemically strengthened glass, tempered glass, or any combination thereof.

19. The liquid crystal device of claim 17 or claim 18, further comprising:(a) a first interlayer and / or a first insulating gas disposed between the first and third glass substrates; and / or(b) a second interlayer and / or a second insulating gas disposed between the second and fourth glass substrates; optionally wherein the first and / or second interlayers comprise polyvinyl butyral (PVB), ethylene -vinyl acetate (EVA), polylactic acid, polyurethanes, ionoplast polymer, or any combination thereof; optionally wherein at least one of the first interlayer and second interlayer has a UV transmittance of less than 5%.

20. The liquid crystal device of any preceding claim, wherein at least one of the first stable state and the second stable state comprises nematic liquid crystals aligned perpendicular or parallel to at least one of the first orientation layer, the second orientation layer, the first electrode, and the second electrode.

21. The liquid crystal device of any preceding claim, wherein the liquid crystal device is a component of a window or a display.

22. The liquid crystal device of any preceding claim, further comprising a compensation film between at least one of (1) the first polarizer and the liquid crystal layer, and (2) the second polarizer and the liquid crystal layer.

23. The liquid crystal device of any preceding claim, wherein: the first and second transmission axes are orthogonal; at least one of the first and second orientation layers is a grating having a grating direction; and the grating direction is 40-50 degrees relative to the first or second transmission axis.

24. The liquid crystal device of any preceding claim, wherein: the first and second transmission axes are parallel; at least one of the first and second orientation layers is a grating having a grating direction; and the grating direction is 40-50 degrees relative to the first or second transmission axis.

25. The liquid crystal device of any preceding claim, wherein: the first and second electrodes are disposed between the first and second glass substrates.

26. A method for switching the liquid crystal device of any preceding claim, the method comprising: when in the first stable state, applying to the first and second electrodes a first stimulus comprising at least one first voltage pulse comprising the first polarity to switch the first stable state to the second stable state; and / or when in the second stable state, applying to the first and second electrodes a second stimulus comprising at least one second voltage pulse comprising the second polarity to switch the second stable state to the first stable state.

27. The method of claim 26, wherein at least one of the first and second voltage pulses is 30 V or less.

28. The method of claim 26 or 27, wherein the liquid crystal device is in the first stable state, and the first stimulus further comprises, prior to applying the at least one first voltage pulse comprising the first polarity, applying at least one first bipolar voltage pulse sufficient to lower a first magnitude of the at least one first voltage pulse necessary to switch the first stable state to the second stable state.

29. The method of any one of claims 26-28, wherein the second stimulus further comprises, prior to applying the at least one second voltage pulse comprising the second polarity, applying at least one second bipolar voltage pulse sufficient to lower a second magnitude of the at least one second voltage pulse necessary to switch the second stable state to the first stable state.

30. A method of making the liquid crystal device of any one of claims 1-25, the method comprising, in any order: providing the first and second glass substrates, the first and second polarizers, the first and second electrodes, the first and second orientation layers, and the liquid crystal layer;disposing the first and second orientation layers between the first and second electrodes; and positioning the liquid crystal layer between the first and second orientation layers.

31. A liquid crystal device comprising a liquid crystal window, the liquid crystal window comprising: a liquid crystal cell, comprising: first and second polarizers having first and second transmission axes, respectively; first and second electrodes; first and second orientation layers disposed between the first and second electrodes, the liquid crystal layer in electrical communication with the first and second electrodes; a liquid crystal layer disposed between the first and second orientation layers; and first and second glass substrates, wherein the first and second electrodes and the first and second polarizers are disposed between the first and second glass substrates; third and fourth glass substrates; wherein the first and second glass substrates are disposed between the third and fourth glass substrates, the first and third glass substrates being proximal to one another and the second and fourth glass substrates being proximal to one another; a first insulating gas disposed between the first and third glass substrates; a second insulating gas disposed between the second and fourth glass substrates; and a frame attached to minor surfaces of the first, second, third, and fourth glass substrates; wherein: the liquid crystal layer comprises a nematic liquid crystal; at zero applied voltage to the first and second electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state by way of alignment imparted by at least one of the first and second orientation layers; the first stable state is switchable to the second stable state by application of a first stimulus, and the second stable state is switchable to the first stable state by application of a second stimulus; the liquid crystal cell has visible light transmittance in the first stable state that is different by at least 20% from visible light transmittance in the second stable state; andthe liquid crystal cell has haze of less than 5% in both the first stable state and the second stable state.

32. A liquid crystal device comprising an insulated glass unit, the insulated glass unit comprising: a liquid crystal cell, comprising: first and second polarizers having first and second transmission axes, respectively; first and second electrodes; first and second orientation layers disposed between the first and second electrodes, the liquid crystal layer in electrical communication with the first and second electrodes; a liquid crystal layer disposed between the first and second orientation layers; and first and second glass substrates, wherein the first and second electrodes and the first and second polarizers are disposed between the first and second glass substrates; a third glass substrate; and a first insulating gas disposed between the first and third glass substrates; wherein: the liquid crystal layer comprises a nematic liquid crystal; at zero applied voltage to the first and second electrodes, at least a portion of the liquid crystal is present in at least one of a first stable state and a second stable state by way of alignment imparted by at least one of the first and second orientation layers; the first stable state is switchable to the second stable state by application of a first stimulus, and the second stable state is switchable to the first stable state by application of a second stimulus; the liquid crystal cell has visible light transmittance in the first stable state that is different by at least 20% from visible light transmittance in the second stable state; and the liquid crystal cell has haze of less than 5% in both the first stable state and the second stable state.

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