WO2019226537A1 - Liquid lens and fluids for liquid lens - Google Patents

Abstract

An electrowetting optical device and a method of decreasing freezing point of the conductive liquid in a liquid lens are disclosed. The electrowetting optical device may include a conductive liquid, a non-conductive liquid, and a dielectric surface. The conductive liquid may comprise a biological compound. The biological compound decreases a freezing point of the conductive liquid. The dielectric surface may be in contact with both the conductive and non-conductive liquids. The conductive and non-conductive liquids may be substantially non-miscible.

Description

LIQUID LENS AND FLUIDS FOR LIQUID LENS

CROSS-REFERENCE TO RELATED APPLICATIONS

[OOOl] This application claims the benefit of priority under 35 U.S.C. § 1 19 of U.S. Provisional Application No. 62/674,979, filed May 22, 2018, the content of which is incorporated herein by reference in its entirety.

FIELD OF THE DISCLOSURE

[0002] The present disclosure relates generally to liquid lenses and, more specifically, electrowetting based liquid lenses using antifreeze peptides (AFPs) or ice recrystallization inhibition proteins (IRIPs).

BACKGROUND

[0003] Conventional electrowetting based liquid lenses have two immiscible liquids disposed within a chamber, namely an oil and a conductive phase. Varying an electric field applied to the liquids can vary the wettability of one of the liquids relative to walls of a chamber of an electrowetting optical device, which has the effect of varying the shape of a meniscus formed between the two liquids.

[0004] Due to liquid lenses being applied in various new fields, it may be desirable for the liquid formulations used in the electrowetting optical field to be enabled at lower temperatures while also being able to quickly respond to voltages across a wide range of temperatures. Among the drawbacks of using known liquid formulations at lower temperatures is the high viscosity of the liquid formulations.

[0005] Accordingly, there is a need for liquids used in liquid lens configurations to provide improved chemical and low temperature stability, such as low viscosity and low freezing points, which can translate into improved liquid lens stability, performance, and manufacturing cost.

SUMMARY OF THE DISCLOSURE

[0006] According to some aspects of the present disclosure, an electrowetting optical device may include a conductive liquid, a non-conductive liquid, and a dielectric surface. The conductive liquid may comprise a biological compound. The biological compound decreases a freezing point of the conductive liquid. The dielectric surface may be in contact with both the conductive and non-conductive liquids. The conductive and non-conductive liquids may be substantially non- miscible.

[0007] Optionally, in one embodiment, the biological compound decreases the viscosity of the conductive liquid.

[0008] In some embodiments, the biological compound comprises antifreeze proteins (AFPs) or ice recrystallization inhibition proteins (IRIPs).

[0009] Optionally, in some embodiments, a ratio of viscosity (cP) of the conductive liquid between -20 °C and 60 °C is less than about 9.

[0010] Optionally, in some embodiments, a ratio of viscosity (cP) of the conductive liquid between -20 °C and 60 °C is less than about 8.

[0011] Optionally, in some embodiments, the antifreeze proteins or ice recrystallization inhibition proteins may comprise at least 8 amino acids, for example.

[0012] Optionally, in some embodiments, the antifreeze proteins or ice recrystallization inhibition proteins may comprise at least 1 1 amino acids, for example.

[0013] Optionally, in some embodiments, the conductive liquid comprises from about 1 x10 ¹⁰ % mol/mol to about 40 % mol/mol of the biological compound.

[0014] Optionally, in some embodiments, the conductive liquid comprises from about 1 x10 ¹⁰ % mol/mol to about 30 % mol/mol of the biological compound.

[0015] Optionally, in some embodiments, the conductive liquid comprises from about 1 x10 ¹⁰ % mol/mol to about 20 % mol/mol of the biological compound.

[0016] Optionally, in some embodiments, the conductive liquid comprises from about 1 x10 ¹⁰ % mol/mol to about 10 % mol/mol of the biological compound.

[0017] Optionally, in some embodiments, the conductive liquid comprises from about 1 x10 ¹⁰ % mol/mol to about 1 % mol/mol of the biological compound.

[0018] Optionally, in some embodiments, the conductive liquid further comprises one or more salts.

[0019] Optionally, in some embodiments, the salts may comprise halide salts, such as bromide, fluoride, iodide salts or combinations thereof. [0020] Optionally, in some embodiments, the conductive liquid further comprises preservatives or biocidal compounds.

[0021] Optionally, in some embodiments, the biocidal compounds comprise methylchloroisothiazolinone or Kathon™ biocide.

[0022] In another embodiment, a conductive liquid may include a biological compound in which the biological compound decreases freezing point of the conductive liquid.

[0023] In a further embodiment, a method of decreasing freezing point of the conductive liquid in a liquid lens may be carried out by the steps of adding a biological compound to a conductive liquid; and the step of decreasing viscosity and freezing point of the conductive liquid in the presence of the biological compound.

[0024] Optionally, in some embodiments, the method further comprises stabilizing the biological compound by adding one or more preservatives or biocidal compounds.

[0025] Additional features and advantages of the present 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 embodiments described herein, including the detailed description, which follows, the claims, and the appended drawings.

[0026] It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated into and constitute a part of this specification. The drawings illustrate the various embodiments described herein, and together with the description serve to explain the principles and operations of the claimed subject matter.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

[0027] The following is a description of the figures in the accompanying drawings. The figures are not necessarily to scale, and certain features and certain views of the figures may be shown exaggerated in scale or in schematic in the interest of clarity or conciseness.

[0028] FIG. 1 is a schematic cross-sectional view of an exemplary electrowetting optical device according to some embodiments of the present disclosure. [0029] FIG. 2 is a plot illustrating the freezing point vs. concentration of a variety of additives in water.

[0030] The foregoing summary, as well as the following detailed description of certain inventive techniques, will be better understood when read in conjunction with the figures. It should be understood that the claims are not limited to the arrangements and instrumentality shown in the figures. Furthermore, the appearance shown in the figures is one of many ornamental appearances that can be employed to achieve the stated functions of the apparatus.

DETAILED DESCRIPTION

[0031] The present disclosure can be understood more readily by reference to the following detailed description, drawings, examples, and claims, and their previous and following description. However, before the present compositions, articles, devices, and methods are disclosed and described, it is to be understood that this disclosure is not limited to the specific compositions, articles, devices, and methods disclosed unless otherwise specified, as such can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting.

[0032] The following description of the disclosure is provided as an enabling teaching of the disclosure in its currently known embodiments. To this end, those skilled in the relevant art will recognize and appreciate that many changes can be made to the various aspects of the disclosure described herein, while still obtaining the beneficial results of the present disclosure. It will also be apparent that some of the desired benefits of the present disclosure can be obtained by selecting some of the features of the present disclosure without utilizing other features. Accordingly, those who work in the art will recognize that many modifications and adaptations to the present disclosure are possible and can even be desirable in certain circumstances and are a part of the present disclosure. Thus, the following description is provided as illustrative of the principles of the present disclosure and not in limitation thereof.

[0033] Disclosed are materials, compounds, compositions, and components that can be used for, can be used in conjunction with, can be used in preparation for, or are embodiments of the disclosed method and compositions. These and other materials are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these materials are disclosed, specific reference of each various individual and collective combinations and permutation of these compounds may not be explicitly disclosed, yet each is specifically contemplated and described herein.

[0034] 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.

[0035] In this document, relational terms, such as first and second, top and bottom, and the like, 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.

[0036] 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. When 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.

[0037] Whether or not a numerical value or end-point of a range in the specification recites “about,” the numerical value or end-point of a range is intended to include two embodiments: one modified by“about,” and one not modified by“about.” It will be further understood that the end- points of each of the ranges are significant both in relation to the other end-point, and independently of the other end-point.

[0038] The terms“substantial,”“substantially,” and variations thereof as used herein are intended to note that a described feature is equal or approximately equal to a value or description. For example, a“substantially planar” surface is intended to denote a surface that is planar or approximately planar. Moreover,“substantially” is intended to denote that two values are equal or approximately equal. In some embodiments,“substantially” may denote values within about 10% of each other, such as within about 5% of each other, or within about 2% of each other.

[0039] Directional terms as used herein— for example up, down, right, left, front, back, top, bottom— are made only with reference to the figures as drawn and are not intended to imply absolute orientation. [0040] As used herein the terms "the," "a," or "an," mean "at least one," and should not be limited to "only one" unless explicitly indicated to the contrary. Thus, for example, reference to "a component" includes embodiments having two or more such components unless the context clearly indicates otherwise.

[0041] The terms “non-miscible” and “immiscible” refer to liquids that do not form a homogeneous mixture when added together or minimally mix when the one liquid is added into the other. In the present description and in the following claims, two liquids are considered non- miscible when their partial miscibility is below 2%, below 1 %, below 0.5%, or below 0.2%, all values being measured within a given temperature range, for example at 20 °C. The liquids herein have a low mutual miscibility over a broad temperature range including, for example, -30 °C to 85 °C and from -20 °C. to 65 °C.

[0042] The term“conductive liquid”, as used herein means a liquid having a conductivity from about 1x10 ³ S/m to about 1x10² S/m, from about 0.1 S/m to about 10 S/m, orfrom about 0.1 S/m to about 1 S/m. The term“non-conductive liquid”, as used herein means a liquid having little to no measureable conductivity including, for example, a conductivity less than about 1x10 ⁸ S/m, less than about 1x10 ¹° S/m, or less than about 1x10 ¹⁴ S/m.

[0043] The term“a ratio of viscosity of a liquid at different temperatures”, as used herein means the ratio of a viscosity of a liquid at one temperature over a viscosity of the liquid at another temperature.

[0044] Broadly, the present disclosure relates to liquid lenses, and more specifically, electrowetting based liquid lenses using antifreeze peptides (AFPs) or ice recrystallization inhibition proteins. In various embodiments, an electrowetting optical device is provided. The electrowetting optical device includes a conductive liquid and a non-conductive liquid. The electrowetting optical device additionally includes a dielectric surface in contact with both the conductive and non- conductive liquids where the conductive and non-conductive liquids are non- miscible.

[0045] As described in more detail below in FIG. 1 , a cell of an electrowetting optical device or liquid lens is generally defined by two transparent insulating plates and side walls. The lower plate, which is non-planar, comprises a conical or cylindrical depression or recess, which contains a non-conductive or insulating liquid. The remainder of the cell is filled with an electrically conductive liquid, non-miscible with the insulating liquid, having a different refractive index and substantially the same density. One or more driving electrodes are positioned on the side wall of the recess while a portion on the rear face of the lower plate provides electrical contact. An insulating thin layer may be introduced between the driving electrode(s) and the respective liquids to provide electrowetting on the dielectric surface having long term chemical stability. A common electrode is in contact with the conductive liquid. Through electrowetting phenomena it is possible to modify the curvature of the interface between the two liquids, according to the voltage V applied between the electrodes. Thus, a beam of light passing through the cell normal to the plates in the region of the liquid will be focused to a greater or lesser extent according to the voltage applied. The conductive liquid generally is an aqueous liquid containing salts. The non-conductive liquid is typically an oil, an alkane or a mixture of alkanes, possibly halogenated.

[0046] In some embodiments, the voltage differential between the voltage at the common electrode and the voltage at the driving electrode can be adjusted. The voltage differential can be controlled and adjusted to move an interface between the liquids (i.e., a meniscus) to a desired position along the sidewalls of the cavity. By moving the interface along sidewalls of the cavity, it is possible to change the focus (e.g., diopters), tilt, astigmatism, and/or higher order aberrations of the liquid lens. Further, during operation of the liquid lens, the dielectric and/or surface energy properties of the liquid lens and its constituents can change. For example, the dielectric properties of the liquids and/or insulating elements can change in response to exposure to the voltage differential over time, changes in temperature, and other factors. As another example, the surface energy of the insulating elements can change in response to exposure to the first and second liquids over time. In still other examples, chemical reactions may exist between constituents of the conductive liquid, which can contain highly nucleophilic species, and constituents of the non- conductive liquid. In turn, the changes in the properties of the liquid lens and those of its constituents (e.g., its insulating elements) can degrade the reliability and performance characteristics of the liquid lens.

[0047] Liquid Lens Structure

[0048] Referring now to FIG. 1 , a simplified cross-sectional view of an exemplary of the liquid lens 100 is provided. The structure of the liquid lens 100 is not meant to be limiting and may include any structure known in the art. In some embodiments, the liquid lens 100 may comprise a lens body 102 and a cavity 104 formed in the lens body. A first liquid 106 and a second liquid 108 may be disposed within cavity 104. In some embodiments, first liquid 106 may be a polar liquid, also referred to as the conducting liquid. Additionally, or alternatively, second liquid 108 may be a non-polar liquid and/or an insulating liquid, also referred to as the non-conducting liquid. In some embodiments, an interface 1 10 between first liquid 106 and second liquid 108 forms a lens. For example, first liquid 106 and second liquid 108 may be substantially immiscible with each other and have different refractive indices such that interface 110 between the first liquid and the second liquid forms a lens. In some embodiments, first liquid 106 and second liquid 108 may have substantially the same density, which can help to avoid changes in the shape of interface 1 10 as a result of changing the physical orientation of the liquid lens 100 (e.g., as a result of gravitational forces).

[0049] In some embodiments of the liquid lens 100 depicted in FIG. 1 , cavity 104 may comprise a first portion, or headspace, 104A and a second portion, or base portion, 104B. For example, second portion 104B of cavity 104 may be defined by a bore in an intermediate layer of the liquid lens 100 as described herein. Additionally, or alternatively, first portion 104A of cavity 104 may be defined by a recess in a first outer layer of the liquid lens 100 and/or disposed outside of the bore in the intermediate layer as described herein. In some embodiments, at least a portion of first liquid 106 may be disposed in first portion 104A of cavity 104. Additionally, or alternatively, second liquid 108 may be disposed within second portion 104B of cavity 104. For example, substantially all or a portion of second liquid 108 may be disposed within second portion 104B of cavity 104. In some embodiments, the perimeter of interface 1 10 (e.g., the edge of the interface in contact with the sidewall of the cavity) may be disposed within second portion 104B of cavity 104.

[0050] Interface 1 10 of the liquid lens 100 (see FIG. 1 ) can be adjusted via electrowetting. For example, a voltage can be applied between first liquid 106 and a surface of cavity 104 (e.g., a or several driving electrode(s) positioned near the surface of the cavity and insulated from the first liquid as described herein) to increase or decrease the wettability of the surface of the cavity with respect to the first liquid and change the shape of interface 110. In some embodiments, adjusting interface 1 10 may change the shape of the interface, which changes the focal length or focus of the liquid lens 100. For example, such a change of focal length can enable the liquid lens 100 to perform an autofocus function. Additionally, or alternatively, adjusting interface 1 10 may tilt the interface relative to an optical axis 112 of the liquid lens 100. For example, such tilting can enable the liquid lens 100 to perform an optical image stabilization (OIS) function in addition to providing astigmatism variations or higher order optical aberration corrections. Adjusting interface 1 10 may be achieved without physical movement of the liquid lens 100 relative to an image sensor, a fixed lens or lens stack, a housing, or other components of a camera module in which the liquid lens can be incorporated. [0051] In some embodiments, lens body 102 of the liquid lens 100 may comprise a first window 114 and a second window 1 16. In some of such embodiments, cavity 104 may be disposed between first window 1 14 and second window 1 16. In some embodiments, lens body 102 may comprise a plurality of layers that cooperatively form the lens body. For example, in the embodiments shown in FIG. 1 , lens body 102 may comprise a first outer layer 1 18, an intermediate layer 120, and a second outer layer 122. In some of such embodiments, the intermediate layer 120 may comprise a bore formed therethrough. First outer layer 118 may be bonded to one side (e.g., the object side) of intermediate layer 120. For example, first outer layer 1 18 may be bonded to intermediate layer 120 at a bond 134A. Bond 134A may be an adhesive bond, a laser bond (e.g., a laser weld), a mechanical closing, or any another suitable bond capable of maintaining first liquid 106 and second liquid 108 within cavity 104. Additionally, or alternatively, second outer layer 122 may be bonded to the other side (e.g., the image side) of intermediate layer 120. For example, second outer layer 122 may be bonded to intermediate layer 120 at a bond 134B and/or a bond 134C, each of which can be configured as described herein with respect to bond 134A. In some embodiments, intermediate layer 120 may be disposed between first outer layer 1 18 and second outer layer 122, the bore in the intermediate layer may be covered on opposing sides by the first outer layer and the second outer layer, and at least a portion of cavity 104 may be defined within the bore. Thus, a portion of first outer layer 118 covering cavity 104 may serve as first window 1 14, and a portion of second outer layer 122 covering the cavity may serve as second window 1 16.

[0052] In some embodiments, cavity 104 may comprise first portion 104A and second portion 104B. For example, in the embodiments shown in FIG. 1 , second portion 104B of cavity 104 may be defined by the bore in intermediate layer 120, and first portion 104A of the cavity may be disposed between the second portion of the cavity and first window 1 14. In some embodiments, first outer layer 1 18 may comprise a recess as shown in FIG. 1 , and first portion 104A of cavity 104 may be disposed within the recess in the first outer layer. Thus, first portion 104A of cavity may be disposed outside of the bore in intermediate layer 120.

[0053] In some embodiments, cavity 104 (e.g., second portion 104B of the cavity) may be tapered as shown in FIG. 1 such that a cross-sectional area of the cavity decreases along optical axis 1 12 in a direction from the object side to the image side. For example, second portion 104B of cavity 104 may comprises a narrow end 105A and a wide end 105B. The terms“narrow” and “wide” are relative terms, meaning the narrow end is narrower than the wide end. Such a tapered cavity can help to maintain alignment of interface 1 10 between first liquid 106 and second liquid 108 along optical axis 1 12. In other embodiments, the cavity is tapered such that the cross- sectional area of the cavity increases along the optical axis in the direction from the object side to the image side or non-tapered such that the cross-sectional area of the cavity remains substantially constant along the optical axis.

[0054] In some embodiments, image light may enter the liquid lens 100 depicted in FIG. 1 through first window 114, may be refracted at interface 110 between first liquid 106 and second liquid 108, and may exit the liquid lens through second window 1 16. In some embodiments, first outer layer 1 18 and/or second outer layer 122 may comprise a sufficient transparency to enable passage of the image light. For example, first outer layer 1 18 and/or second outer layer 122 may comprise a polymeric, glass, ceramic, or glass-ceramic material. In some embodiments, outer surfaces of first outer layer 1 18 and/or second outer layer 122 may be substantially planar. Thus, even though the liquid lens 100 can function as a lens (e.g., by refracting image light passing through interface 1 10), outer surfaces of the liquid lens can be flat as opposed to being curved like the outer surfaces of a fixed lens. In other embodiments, outer surfaces of the first outer layer and/or the second outer layer may be curved (e.g., concave or convex). Thus, the liquid lens may comprise an integrated fixed lens. In some embodiments, intermediate layer 120 may comprise a metallic, polymeric, glass, ceramic, or glass-ceramic material. Because image light can pass through the bore in intermediate layer 120, the intermediate layer may or may not be transparent.

[0055] In some embodiments, the liquid lens 100 (see FIG. 1 ) may comprise a common electrode 124 in electrical communication with first liquid 106. Additionally, or alternatively, the liquid lens 100 may comprise one or several driving electrode(s) 126 disposed on a sidewall of cavity 104 and insulated from first liquid 106 and second liquid 108. Different voltages can be supplied to common electrode 124 and driving electrode(s) 126 to change the shape of interface 1 10 as described herein.

[0056] In some embodiments, the liquid lens 100 (see FIG. 1 ) may comprise a conductive layer 128 at least a portion of which is disposed within cavity 104. For example, conductive layer 128 may comprise a conductive coating applied to intermediate layer 120 prior to bonding first outer layer 1 18 and/or second outer layer 122 to the intermediate layer. Conductive layer 128 may comprise a metallic material, a conductive polymer material, another suitable conductive material, or a combination thereof. Additionally, or alternatively, conductive layer 128 may comprise a single layer or a plurality of layers, some or all of which can be conductive. In some embodiments, conductive Iayer 128 may define common electrode 124 and/ordriving electrode(s) 126. For example, conductive layer 128 may be applied to substantially the entire outer surface of intermediate layer 118 prior to bonding first outer conductive layer 128 to intermediate layer 1 18, the conductive layer may be segmented into various conductive elements (e.g., common electrode 124 and/or driving electrode 126). In some embodiments, the liquid lens 100 may comprise a scribe 130A in conductive layer 128 to isolate (e.g., electrically isolate) common electrode 124 and driving electrode 126 from each other. In some embodiments, scribe 130A may comprise a gap in conductive layer 128. For example, scribe 130A is a gap with a width of about 5 micrometer (pm), about 10 pm, about 15 pm, about 20 pm, about 25 pm, about 30 pm, about 35 pm, about 40 pm, about 45 pm, about 50 pm, or any ranges defined by the listed values.

[0057] As also depicted in FIG. 1 , the liquid lens 100 may comprise an insulating element or layer 132 disposed within cavity 104, on top on the driving electrode layer. For example, insulating element 132 may comprise an insulating coating applied to intermediate layer 120 prior to bonding first outer layer 1 18 and/or second outer layer 122 to the intermediate layer. In some embodiments, insulating element 132 may comprise an insulating coating applied to conductive layer 128 and second window 1 16 after bonding second outer layer 122 to intermediate layer 120 and prior to bonding first outer layer 1 18 to the intermediate layer. Thus, the insulating element 132 may cover at least a portion of conductive layer 128 within cavity 104 and second window 1 16. In some embodiments, insulating element 132 may be sufficiently transparent to enable passage of image light through second window 1 16 as described herein.

[0058] In some embodiments of the liquid lens 100 depicted in FIG. 1 , the insulating element 132 may cover at least a portion of driving electrode 126 (e.g., the portion of the driving electrode disposed within cavity 104) to insulate first liquid 106 and second liquid 108 from the driving electrode. Additionally, or alternatively, at least a portion of common electrode 124 disposed within cavity 104 may be uncovered by insulating element 132. Thus, common electrode 124 may be in electrical communication with first liquid 106 as described herein.

[0059] In some embodiments, insulating element 132 may comprise a hydrophobic surface layer of second portion 104B of cavity 104. Such a hydrophobic surface layer can help to maintain second liquid 108 within second portion 104B of cavity 104 (e.g., by attraction between the non- polar second liquid and the hydrophobic material) and/or enable the perimeter of interface 110 to move along the hydrophobic surface layer (e.g., by electrowetting) to change the shape of the interface as described herein. Further, the liquid lens 100 shown in FIG. 1 , based at least in part on the insulating element 132, may exhibit a contact angle hysteresis (i.e., at the interface 1 10 between the liquids 106, 108) of no more than 3°. [0060] As used herein, the“contact angle hysteresis” refers to the differential in measured contact angles of the second liquid 108 with the insulating element 132 upon a sequential application of a driving voltage to the driving electrode 126 (e.g., the differential between the driving voltage supplied to the driving electrode and the common voltage supplied to the common electrode) from 0 V to a maximum driving voltage, followed by a return to 0 V (i.e., as relative to the common electrode 124). The initial contact angle without voltage may be a maximum of 25° and increases to the contact angle due to the electrowetting effect may be at least 15° at“the maximum driving voltage”, as used herein. In other embodiments the driving voltage may provide an AC 1 kHz voltage. In some embodiments, the useful voltage may range from about 25V to about 70V. The choice of driver used to apply the voltage is not meant to be limiting, and the insulating layer 132 thickness may be tuned to fit any driving voltage range delivered by the selected driver.

[0061] To provide a wide range of focal distances, tilt angles, and/or astigmatism variations, a significant difference in the optical index between the conductive and non-conductive liquids is beneficial. Traditionally, the oil composition (non-conductive liquid) has a higher optical index than the conductive liquid. The optical index of pure water is about 1 .33, but water is usually modified with additives to achieve higher optical index values to meet the specifications of commercial liquid lenses. The description and corresponding material properties for these two respective liquids is provided below.

[0062] Conductive Liquid

[0063] In some embodiments, the conductive liquid may be an aqueous solution. In other embodiments, the conductive liquid may include no water. In some embodiments, the conductive liquid may comprise polar solvents. In some embodiments, the conductive liquid may include from about 0.01 % w/w to about 100 % w/w, from about 0.1 % w/w to about 50 % w/w, from about 0.1 % w/w to about 25 % w/w, from about 0.1 % w/w to about 15 % w/w, from about 1 % w/w to about 10 % w/w, or from about 1 % w/w to about 5 % w/w of water, based on the total weight of the conductive liquid.

[0064] In some embodiments, the conductive liquid may include from about 1 x10 ¹⁰ % mol/mol to about 100 % mol/mol, 1x10 ¹⁰ % mol/mol to about 80 % mol/mol, 1x10 ¹⁰ % mol/mol to about 60 % mol/mol, 1x10 ¹⁰ % mol/mol to about 40 % mol/mol, 1x10 ¹⁰ % mol/mol to about 30 % mol/mol, from about 1x10 ¹⁰ % mol/mol to about 20 % mol/mol, 1x10 ¹⁰ % mol/mol to about 10 % mol/mol, 1 x10 ¹⁰ % mol/mol to about 1 % mol/mol, from about 1x10 ⁶ % mol/mol to about 80 % mol/mol, from about 1x10³ % mol/mol to about 80 % mol/mol, from about 1x10 ² % mol/mol to about 80 % mol/mol, from about 1 % mol/mol to about 60 % mol/mol, from about 50 % mol/mol to about 100 % mol/mol, from about 75 % mol/mol to about 95 % mol/mol, or from about 2 % mol/mol to about 25 % mol/mol of a biological compound, based on the total weight of the conductive liquid.

[0065] In some embodiments, the biological compound may comprise antifreeze proteins (AFPs) or ice recrystallization inhibition proteins (IRIPs). In some embodiments, the antifreeze proteins or ice recrystallization inhibition proteins comprise at least 8 amino acids, for example. In some embodiments, the antifreeze proteins or ice recrystallization inhibition proteins comprise at least 1 1 amino acids, for example. Advantageously, the AFPs or IRIPs included in the conductive liquid decrease the freezing point and/or viscosity of conductive liquids without altering or significantly altering the optical properties of conductive liquid. Further advantage of adding biological compound may replace or decrease the need for other anti-freezing point agent or freezing-point lowering agent, such as ethylene glycol, for example. Reducing or eliminating such other anti-freezing point agent or freezing-point lowering agent may enable the conductive liquid to have a suitably low freezing point (e.g., about -20 °C or less, -30 °C or less, or -40 °C or less) while maintaining a relatively low viscosity (e.g., a low temperature viscosity) and/or a relatively small viscosity dependence on temperature as described herein. Further reducing or eliminating such other anti-freezing point agent or freezing-point lowering agent may provide the conductive liquid more stability, conductivity and low corrosivity.

[0066] AFPs have an affinity for ice, by virtue of structural complementarity, thereby inhibiting its growth. Adsorption of AFPs onto ice surfaces has two distinct effects: thermal hysteresis (TH) and recrystallization inhibition (Rl). Without wishing to be bound by any theory, it is believed that TH results from a non-colligative freezing point depression as ice-front growth becomes restricted to sterically unfavourable spaces between AFPs (Raymond & DeVries 1977). This broadens the gap between the melting and freezing points of ice, this range being the measure of TH. Without wishing to be bound by any theory, it is believed that AFPs mediate the effect of Rl by interfering with the migration of ice boundaries that normally thermodynamically favor the creation of large, ice crystals at the expense of smaller ones (Knight, DeVries & Oolman 1984). AFPs have been isolated from a number of freeze-tolerant plant species, including bittersweet nightshade.

[0067] Among the several types of AFPs, Type I AFPs may include alanine-rich peptides found in blood samples from winter flounder (Pseudopleuronectes americanus) and shorthorn sculpin (Myoxocephalus scorpius). To date, three-dimensional (3D) structures of the AFPs HPLC6 and ss3 have been solved and their ice-binding residues have been identified using structure-based mutagenesis studies. Accumulated structure-function relationship studies on Type I AFPs have revealed that common Ala-rich hydrophobic regions may enable potent antifreeze activity.

[0068] IRIPs may include apoplastically targeted proteins with two potential ice-binding motifs: 1-9 leucine-rich repeats (LRRs) and c. 16‘IRIP’ repeats. IRIP genes appear to be confined to the grass subfamily Pooideae and their products, exhibit sequence similarity to phytosulphokine receptors and are predicted to adopt conformations with two ice-binding surfaces. D. antarctica IRIP (DalRIP) transcript levels are greatly enhanced in leaf tissue following cold acclimation. Transgenic Arabidopsis thaliana expressing a DalRIP has novel Rl activity, and purified DalRIP, when added back to extracts of leaves from non-acclimated D. Antarctica, can reconstitute the activity found in acclimated plants.

[0069] In some embodiments, the water and/or polar solvent may be mixed with one or more different salts including either organic and/or inorganic salts. The term,“ionic salts”, as referred to herein, refers to salts that are totally or substantially dissociated in water (such as an acetate- anion and a cation). Likewise, the term,“ionizable salts”, as referred to herein, refers to salts that are totally or substantially dissociated in water, after chemical, physical or physico-chemical treatment. Examples of anions used in these types of salts include, but are not limited to, halides, (such as fluorides, bromides, or iodides), sulfate, carbonate, hydrogen carbonate, acetate, 2- fluoracetate, 2,2-difluoroacetate, 2,2,2-trifluoroacetate, 2,2,3,3,3-pentafluoropropanoate, triflate, fluoride, hexafluorophosphate, trifluoromethanesulfonate, and mixtures thereof. Examples of cations used in these types of salts include, but are not limited to, alkali/alkaline earth and metallic cations e.g. sodium, magnesium, potassium, lithium, calcium, zinc, fluorinated ammonium, e.g. N-(fluoromethyl)-2-hydroxy-N,N-dimethyl-ethanaminium, and mixtures thereof. In some embodiments, any combination of the above-referenced anions and cations may be used in the conductive liquid.

[0070] In some embodiments, at least one organic and/or inorganic ionic or ionizable salt is used to confer conductive properties to the water and decrease the freezing point of the mixed fluid. In some embodiments, the ionic salts may include, for example, sodium sulfate, potassium acetate, sodium acetate, zinc bromide, sodium bromide, lithium bromide, and combinations thereof. In other embodiments, the ionic salt may include fluorinated salts including fluorinated organic ionic salts. In some embodiments, the organic and inorganic ionic and ionizable salts may include, but are not limited to, potassium acetate, magnesium chloride, zinc bromide, lithium bromide, lithium chloride, calcium chloride, sodium sulfate, sodium triflate, sodium acetate, sodium trifluoroacetate and the like, as well as mixtures thereof.

[0071] Fluorinated salts or fluoride salts, including fluorinated organic ionic salts, can advantageously maintain a relatively low refractive index of the conductive liquid while facilitating changes of the physical properties of the conductive liquid, such as lowering the freezing point of the conductive liquid. Fluorinated salts, unlike traditional chloride salts, may also demonstrate reduced corrosion with the materials constituting the cell of the electrowetting optical device, e.g. the steel, stainless steel, or brass components.

[0072] The water used in the conductive liquid is preferred to be as pure as possible, i.e. free, or substantially free, of any other undesired dissolved components that could alter the optical properties of the electrowetting optical device. In some embodiments, ultrapure water (UPW) having a conductivity of about 0.055 pS/cm at 25 °C or a resistivity of 18.2 MOhm is used to form the conductive liquid.

[0073] In some embodiments, the conductive liquid may include, in addition to the biological compounds, an anti-freezing agent or freezing-point lowering agent. The use of anti-freezing agents such as salts, alcohols, diols, and/or glycols allows the conductive liquid to remain in a liquid state within a temperature range from about -30 °C to about +85 °C, from about -20 °C to about +65 °C, or from about -10 °C to about +65 °C. In some embodiments, the use of the alcohol and/or glycol additives in the conductive and/or non-conductive liquids can help provide a steady interface tension between the two liquids over a broad range of temperature. Depending on the desired application and properties desired from the conductive liquid and resultant liquid lens, the conductive liquid may include less than about 95% by weight, less than about 90% by weight, less than about 80% by weight, less than about 70% by weight, less than about 60% by weight, less than about 50% by weight, less than about 40% by weight, less than about 30% by weight, less than about 20% by weight, less than about 10% by weight, or less than about 5% by weight anti-freezing agent. In some embodiments, the conductive liquid may include more than about 95% by weight, more than about 90% by weight, more than about 80% by weight, more than about 70% by weight, more than about 60% by weight, more than about 50% by weight, more than about 40% by weight, more than about 30% by weight, more than about 20% by weight, more than about 10% by weight, or more than about 5% by weight anti-freezing agent. In some embodiments, the anti-freezing agent may be a glycol including, for example, monopropylene glycol, ethylene glycol, 1 ,3-propanediol (trimethylene glycol or TMG), glycerol, dipropylene glycol, and combinations thereof. In some embodiments using glycols, the glycol may have a weight average molecular weight (Mw) from 200 g/mol to 2000 g/mol, from 200 g/mol to 1000 g/mol, from 350 g/mol to 600 g/mol, from 350 g/mol to 500 g/mol, from 375 g/mol to 500 g/mol, or a mixture thereof. In some embodiments, the glycol may be a dimer, trimer, tetramer, or any combination from 2 to 100 monomer diol or triol units including all integers in between.

[0074] In some embodiments, the conductive liquid may include at least one viscosity controlling agent, namely a viscosity-adjusting agent. The viscosity-adjusting agent may include any compound or mixture known in the art and may include, for example, an alcohol, a glycol, a glycol ether, a polyol, a poly ether polyol and the like, or mixtures thereof. In some embodiments, the viscosity-adjusting agent may include, for example, ethanol, ethylene glycol (EG), monopropylene glycol (MPG), 1 ,3-propane diol, 1 ,2,3-propane triol (glycerol), and mixtures thereof. In some embodiments, the viscosity-adjusting agent has a molecular weight of less than about 130 g/mol. In some embodiments, the same or different alcohols, diols, and/or glycols may be used as the anti-freezing agent or viscosity-controlling agent, respectfully.

[0075] In some embodiments, the conductive liquid may include a preservative agent or biocide agent to prevent the development of organic elements, such as bacteria, fungi, algae, micro-algae, and the like, which could worsen the optical properties of the optical electrowetting device, particularly in the case of the lens driven by electrowetting. The biocide agent should not alter or minimally alter the required optical properties of the conductive liquid (e.g. transparency and refractive index). Biocide compounds include those known in the art, such as , for example, methylchloroisothiazolinone, also known as Kathon CG, 2- methyM-isothiazoline-3-one (MIT) and 1 ,2-benzisothiozoline-3-one (BIT).

[0076] The conductive liquids (polar fluid/liquid) disclosed herein that are used in liquid lens/electrowetting optical applications may provide a wide range of focal distances, tilt angles, and/or astigmatism variations. In order to accomplish these benefits, the conductive liquid should meet at least one or more of the following properties: 1 ) a density matched or similar to the non- conductive liquid over the operating temperature range of the liquid lens; 2) a significant refractive index difference compared to the non-conductive liquid; 3) a low miscibility with the non- conductive liquid over the operating temperature range of the liquid lens; 4) chemical stability with respect to each of the conductive liquid’s components and non-conductive liquid; and 5) an adequate viscosity to match or achieve the desired response time for the liquid lens.

[0077] With regards to the density parameter, substantially matching the density of the conductive liquid with the density of the non-conductive liquid can help contribute to a versatile liquid lens/electrowetting optical device having a wide range of focal distances at a variety of tilt angles. In some embodiments, the difference in densities (Dr) between the non-conductive liquid and conductive liquid may be lower than 0.1 g/cm³, lower than 0.01 g/cm³, or lower than 3.10 g/cm³ over a broad temperature range including from about -30 °C to about 85 °C or from about -20° C to about 65° C.

[0078] In some embodiments, the difference in refractive index (Dh) between the conductive liquid and the non-conductive liquid may range from about 0.02 to about 0.24 or from about 0.05 to about 0.15. This optical index range for optical applications includes features such as variable focus, tilt, astigmatism compensations, and tuning the refractive index to optimize the balance precision versus range.

[0079] In some embodiments, the Dh between the conductive liquid and the non-conductive liquid may be greater than 0.24, greater than 0.27, or greater than 0.29. The higher difference in refractive indices between the two liquids is well suited for optical applications including features such as zoom, variable focus or tilt devices, variable illumination devices wherein the illumination depends on the difference of refractive index between two liquids, and/or optical devices where a tilt of the optical axis can be performed, for example used for light beam deflection or image stabilization applications.

[0080] With regards to the miscibility parameter, the disclosed conductive and non-conductive liquids are considered non-miscible. In some embodiments, the partial miscibility of the conductive and non-conductive liquids may be below 2%, below 1 %, below 0.5%, or below 0.2%, where each of these values may be measured over a broad temperature range including, for example, -30 °C to 85 °C or from -20 °C to 65 °C.

[0081] With regards to the stability parameter, the non-conductive liquid remains in the liquid state within a temperature range from about -10 °C to about +65 °C, from about -20 °C to about +65° C, or from about -30 °C to about +85 °C. Lastly, the individual components of the respective conductive and non-conductive liquids are also chemically stable with respect to each other, i.e. they exhibit no chemical reactivity in presence of other compounds of the conducting and non- conducting liquids within the functional temperature range of the device.

[0082] With regards to the viscosity parameter, a low viscosity may be desired for the conductive liquid in some applications since a less viscous fluid may be able to respond to the varying voltages applied through the cell of the liquid lens/electrowetting optical device more quickly compared to a more viscous fluid. An aqueous based conductive layer’s viscosity is generally low and it responds quickly to voltage changes. In some embodiments, the viscosity changes of the conductive liquid in a controlled temperature range are designed to be similar to that of water in the same controlled temperature range. In some embodiments, the conductive liquid exhibits a limited change in viscosity over a temperature range of -20 °C to +65 °C. For example, a ratio of a low temperature viscosity of the conductive liquid measured at -20 °C to a high temperature viscosity of the conductive liquid measured at +65 °C is about 30, about 25, about 20, about 19, about 18, about 17, about 16, about 15, about 14, about 13, about 12, about 1 1 , about 10, about 9, about 8, about 7, about 6, about 5, about 4, about 3, about 2, or any values therebetween, or any ranges bounded by any combination of these values, although other values can be used in some cases. In some embodiments, the conductive liquid exhibits a limited change in viscosity over a temperature range of -20 °C to +60 °C. For example, a ratio of a low temperature viscosity of the conductive liquid measured at -20 °C to a high temperature viscosity of the conductive liquid measured at +60 °C is about 30, about 25, about 20, about 19, about 18, about 17, about 16, about 15, about 14, about 13, about 12, about 1 1 , about 10, about 9, about 8, about 7, about 6, about 5, about 4, about 3, about 2, or any values therebetween, or any ranges bounded by any combination of these values, although other values can be used in some cases.

[0083] Non-Conductive Liquid

[0084] In some embodiments, the non -conductive liquid disclosed herein includes one or more transmission recovery agents. Depending on the desired application and corresponding properties of the non-conductive liquid, the non-conductive liquid may include from about 1 % w/w to about 35 % w/w transmission recovery agent. In some embodiments, the non-conductive liquid may include from about 1 % w/w to about 60 w/w, from about 1 % w/w to about 25 % w/w, from about 1 % w/w to about 20 % w/w, from about 1 % w/w to about 15 % w/w, from about 1 % w/w to about 10 % w/w, from about 5 % w/w to about 40 % w/w, from about 5 % w/w to about 25 % w/w, from about 5 % w/w to about 20 % w/w, from about 5 % w/w to about 15 % w/w, from about 5 % w/w to about 10 % w/w, from about 10 % w/w to about 25 % w/w, from about 10 % w/w to about 20 % w/w, or from about 10 % w/w to about 15 % w/w of the transmission recovery agent. In some embodiments, the non-conductive liquid may include from about 1 % w/w to about 60 % w/w, from about 5 % w/w to about 40 % w/w, or from about 10 % w/w to about 15 % w/w of the transmission recovery agent. In some embodiments, additional non-reactive compounds (e.g. oils, high or low viscosity liquids, oil soluble solids, etc.) may be respectively added to the non- conductive liquid to modify the final electrical response properties in an amount from about 0.0001 % w/w to about 95 % w/w or from 5 % w/w to about 60 % w/w. [0085] The transmission recovery agents disclosed herein can beneficially provide improved lens/electrowetting optical devices, specifically those devices used across a wide range of temperatures. Improved performance at higher temperatures includes temperatures greater than 45 °C, greater than 50 °C, greater than 55 °C, greater than 60 °C, greater than 65 °C, greater than 70 °C, greater than 75 °C, greater than 80 °C. An improved transmission recovery time designates that the transparency of the lens may be maintained or quickly recover when used across the device’s operating temperature range (e.g. from -20 °C to +70 °C) for a given voltage differential. Conventional liquid lenses without transmission recovery agents frequently form stable emulsions (oil in water or water in oil) and/or form droplets of condensation on the window 1 14 and/or insulating layers 132A. The presence of an emulsion in at least one of the respective liquid layers and/or droplets of condensation on a surface of the liquid lens 100 structure can lead to increased light diffusion, which can contribute to problems associated with focusing and distinguishing contrast between differently colored regions (e.g. black and white). The transmission recovery agents described herein can help to enable improved transmission recovery times of liquid lens/electrowetting optical devices.

[0086] In some embodiments, the conductive liquid includes the transmission recovery agent having Formula (I) and/or Formula (II):

[0087] wherein R1 is an alkyl, cycloalkyl, fluoroalkyl, or alkoxy group. In some embodiments, the transmission recovery agent may include alkyltris(trimethylsiloxy)silanes, fluoroalkyltris(trimethylsiloxy), alkylheptamethyltrisiloxanes, fluoroalkylheptamethyltrisiloxanes, and combinations thereof. In other embodiments, the transmission recovery agent may include n-octyltristrimethylsiloxysilane, 3-n-octylheptamethyltrisiloxane, tridecafluorooctyltris(trimethylsiloxy)silane, and combinations thereof. In other embodiments, the transmission recovery agent may include 3-n-octylheptamethyltrisiloxane, tridecafluorooctyltris(trimethylsiloxy)silane, and combinations thereof. In still other embodiments, the transmission recovery agent does not include n- octyltristrimethylsiloxysilane.

[0088] As used herein,“alkyl” groups include straight chain and branched alkyl groups having from 1 to about 20 carbon atoms, and typically from 1 to 12 carbons or, in some embodiments, from 1 to 8 carbon atoms. As employed herein,“alkyl groups” may include cycloalkyl groups as defined below. Alkyl groups may be substituted or unsubstituted. Examples of straight chain alkyl groups include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n- hexyl, n-heptyl, and n-octyl groups. Examples of branched alkyl groups include, but are not limited to, isopropyl, sec-butyl, t-butyl, neopentyl, and isopentyl groups. Representative substituted alkyl groups may be substituted one or more times with, for example, amino, thio, hydroxy, cyano, alkoxy, and/or halo groups such as F, Cl, Br, and I groups. In some embodiments, the alkyl groups may be substituted one or more times with, for example, cyano, alkoxy, and fluorine groups. As used herein the term haloalkyl is an alkyl group having one or more halo groups. In some embodiments, haloalkyl refers to a per- haloalkyl group. In some embodiments, the“alkyl groups” may specifically exclude the 8 carbon n- octyl group.

[0089] Cycloalkyl groups are cyclic alkyl groups such as, but not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups. In some embodiments, the cycloalkyl group has 3 to 8 ring members, whereas in other embodiments the number of ring carbon atoms range from 3 to 5, 6, or 7. Cycloalkyl groups may be substituted or unsubstituted. Cycloalkyl groups further include polycyclic cycloalkyl groups such as, but not limited to, norbornyl, adamantyl, bornyl, camphenyl, isocamphenyl, and carenyl groups, and fused rings such as, but not limited to, decalinyl, and the like. Cycloalkyl groups also include rings that are substituted with straight or branched chain alkyl groups as defined above. Representative substituted cycloalkyl groups may be mono-substituted or substituted more than once, such as, but not limited to: 2,2-; 2,3-; 2,4-; 2,5-; or 2,6- disubstituted cyclohexyl groups or mono-, di-, or tri- substituted norbornyl or cycloheptyl groups, which may be substituted with, for example, alkyl, alkoxy, amino, thio, hydroxyl, cyano, and/or halo groups.

[0090] In some embodiments, the non-conductive liquid may additionally include an organic or an inorganic (mineral) compound or mixture thereof. Examples of such organic or inorganic compounds include a hydrocarbon, a Si-based monomer or oligomer, a Ge-based monomer or oligomer, a Si— Ge-based monomer or oligomer, a high index polyphenylether compound, a low index fluorinated or perfluorinated hydrocarbon, or mixtures thereof. [0091] The hydrocarbon may be linear or branched and may contain one or more saturated, unsaturated or partially unsaturated cyclic moiety(ies). In some embodiments, the hydrocarbon includes from about 10 to about 35 carbon atoms or from about 20 to about 35 carbon atoms. In other embodiments, the hydrocarbon may further include one or more heteroatoms, as substituents and/or as atoms or groups of atoms interrupting the hydrocarbon chain and/or ring. Such heteroatoms include, but are not limited to oxygen, sulfur, nitrogen, phosphor, halogens (mainly as fluorine, chlorine, bromine and/or iodine). Depending on the application and composition of the conductive phase, the inclusion of one or more heteroatom(s) may negatively impact the immiscibility of the two liquids. In some embodiments, the non-conductive liquid may include from about 1 % to about 99.8 % w/w, 5 % to about 99 % w/w, 10 % to about 95 % w/w, 25 % to about 95 % w/w, or about 50 % to about 95 % w/w, of the hydrocarbon or mixture of hydrocarbons. In some embodiments, the hydrocarbon mixtures may include small amounts of aromatic groups and/or unsaturated moieties in an amount less than about 5 % w/w, less than about 4 % w/w, less than about 3 % w/w, less than about 2 % w/w, less than about 1 % w/w, less than about 0.5 % w/w. In other embodiments, a halide, e.g. chlorine, may be present in the hydrocarbon in an amount less than about 10 % w/w, less than about 7 % w/w, less than about 5 % w/w, less than about 3 % w/w, or less than about 3 % w/w of the non-conductive liquid.

[0092] In some embodiments, the Si-based monomer or oligomer, the Ge-based monomer or oligomer, and/or the Si— Ge-based monomer or oligomer may include one or more of the following structures designated by Formulas III, IV, V, VI:

(V), (¥¾

[0093] where R₂, R3, R4, Rs, R₆, and R₇ are individually alkyl, aryl, (hetero)aryl, (hetero)arylalkyl, alkoxy, or aryloxy groups; X is a group 14 element including, for example, carbon, silicon, germanium, and combinations thereof. In some embodiments, X is carbon, X is silicon, X is germanium, X is a mixture of carbon, silicon, and germanium, or combinations thereof.

[0094] The oligomers used for the Si-based, Ge-based, and/or Si— Ge-based oligomers are compounds having a number of identical (homo-oligomers) or different (co-oligomers) repeating units, of between about 2 and about 20, between about 2 and about 10, or between about 2 and about 5. Oligomers having more than about 20 repeating units may induce an undesirable increase of viscosity at lower temperatures.

[0095] As used herein,“(hetero)aryl” means an aromatic or heteroaromatic radical containing from about 5 to about 12 atoms, forming at least one, aromatic and/or heteroaromatic ring, where the ring is substituted by one or more halogens, one or more acyloxy groups, for example, 1 , 2, 3 halogen atoms (mainly fluorine, chlorine and/or bromine), and being optionally fused with one or more saturated, partially saturated, or unsaturated ring system.

[0096] In some embodiments, the heteroaromatic ring may be substituted with nitrogen, phosphorus, or sulfur substituted aromatic rings. In some embodiments, (hetero)aryls may include, for example, phenyl, naphthyl, bicyclo[4.2.0]octatrienyl substituted ring systems substituted with 2 or 3 halogen atoms in any available position on the ring.

[0097] As used herein,“(hetero)arylalkyl” means the moieties described herein for each of the alkyl and (hetero)aryl substituents substituted with one or more halogens, for example, 1 ,3 halogen atoms (mainly fluorine, chlorine and/or bromine) along the aryl and/or alkyl groups.

[0098] In some embodiments, the organic and/or inorganic compounds of the non-conductive liquid may include hexamethyldisilane, diphenyldimethylsilane, chlorophenyltrimethylsilane, phenyltrimethyl-silane, phenyltris(trimethylsiloxy)silane, polydimethylsiloxane, tetra- phenyltetramethyltrisiloxane, poly(3,3,3-trifluoropropylmethylsiloxane), 3,5,7- triphenylnonamethyl-pentasiloxane, 3,5-diphenyloctamethyltetrasiloxane, 1 ,1 ,5,5- tetraphenyl- 1,3,3,5-tetramethyl-trisiloxane, hexamethylcyclotrisiloxane, hexamethyldigermane, diphenyldimethylgermane, phenyltrimethyl-germane. In some embodiments, the organic and/or inorganic compounds of the non-conductive liquid may include hexamethyldigermane, diphenyldimethylgermane, hexaethyldigermane, parrafin, or combinations thereof. For example, the paraffin oil ISOPAR® P includes a mixture of hydrocarbons produced and made commercially available by Exxon Mobil. In other embodiments, the organic and/or inorganic compounds of the non-conductive liquid may include a high index polyphenylether fluid. In some embodiments, the non-conductive liquid may include from about 1 % to about 99.8 % w/w, 5 % to about 99 % w/w, 10 % to about 95 % w/w, 25 % to about 95 % w/w, or about 50 % to about 95 % w/w, of the organic and/or inorganic compounds. In other embodiments, the non-conductive liquid may include from about 1 % to about 99.8 % w/w, 5 % to about 99 % w/w, 10 % to about 95 % w/w, 25 % to about 95 % w/w, or about 50 % to about 95 % w/w, of the hydrocarbon, organic, and/or inorganic compounds.

[0099] In some embodiments, the non-conductive liquid exhibits a limited change in viscosity over a temperature range of -20 °C to +65 °C. For example, a ratio of a low temperature viscosity of the non-conductive liquid measured at -20 °C to a high temperature viscosity of the non- conductive liquid measured at +65 °C is about 30, about 25, about 20, about 19, about 18, about 17, about 16, about 15, about 14, about 13, about 12, about 1 1 , about 10, about 9, about 8, about 7, about 6, about 5, about 4, about 3, about 2, or any values therebetween, or any ranges bounded by any combination of these values, although other values can be used in some cases. In some embodiments, the non-conductive liquid exhibits a limited change in viscosity over a temperature range of -20 °C to +60 °C. For example, a ratio of a low temperature viscosity of the non- conductive liquid measured at -20 °C to a high temperature viscosity of the non-conductive liquid measured at +60 °C is about 30, about 25, about 20, about 19, about 18, about 17, about 16, about 15, about 14, about 13, about 12, about 1 1 , about 10, about 9, about 8, about 7, about 6, about 5, about 4, about 3, about 2, or any values therebetween, or any ranges bounded by any combination of these values, although other values can be used in some cases.

[00100] The relatively flat viscosity curves of the conductive liquid and/or the non-conductive liquid described herein can enable improved performance of the liquid lens across an operating temperature range (e.g., -20 °C to +65 °C or -20 °C to +60 °C) without controlling the temperature of the liquid lens (e.g., by heating the liquids to achieve a desired viscosity).

[00101] The claims appended hereto should be taken as the sole representation of the breadth of the present disclosure and the corresponding scope of the various embodiments described herein. Further, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims. More specifically, although some aspects of the present disclosure are identified herein as preferred or particularly advantageous, it is contemplated that the present disclosure is not necessarily limited to these aspects.

[00102] It is noted that one or more of the following claims utilize the term "wherein" as a transitional phrase. For the purposes of defining the present disclosure, it is noted that this term is introduced in the claims as an open-ended transitional phrase that is used to introduce a recitation of a series of characteristics of the structure and should be interpreted in like manner as the more commonly used open-ended preamble term "comprising."

[00103] It is also noted that recitations herein of "at least one" component, element, etc., should not be used to create an inference that the alternative use of the articles "a" or "an" should be limited to a single component, element, etc.

[00104] It is further noted that recitations herein of a component of the present disclosure being "configured" in a particular way, to embody a particular property, or to function in a particular manner, are structural recitations, as opposed to recitations of intended use. More specifically, the references herein to the manner in which a component is "configured" denotes an existing physical condition of the component and, as such, is to be taken as a definite recitation of the structural characteristics of the component.

[00105] It is noted that terms like "preferably," "commonly," and "typically," when utilized herein, are not utilized to limit the scope of the claimed invention or to imply that certain features are critical, essential, or even important to the structure or function of the claimed invention. Rather, these terms are merely intended to identify particular aspects of an embodiment of the present disclosure or to emphasize alternative or additional features that may or may not be utilized in a particular embodiment of the present disclosure.

[00106] In this disclosure, it is noted that the terms "substantially" and "approximately" are utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. The terms "substantially" and "approximately" 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.

[00107] While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised that do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.

Claims

What is claimed is:

1. An electrowetting optical device, comprising:

a conductive liquid comprising a biological compound that decreases a freezing point of the conductive liquid;

a non-conductive liquid; and

a dielectric surface in contact with both the conductive and non-conductive liquids.

2. The electrowetting optical device of claim 1 , wherein a ratio of viscosity (cP) of the conductive liquid between -20 °C and 60 °C is less than about 9.

3. The electrowetting optical device of any one of claims 1 -2, wherein the biological compound comprises antifreeze proteins (AFPs) or ice recrystallization inhibition proteins (IRIPs).

4. The electrowetting optical device of claim 3, wherein the antifreeze proteins or ice recrystallization inhibition proteins comprise at least 8 amino acids.

5. The electrowetting optical device of any one of claims 3-4, wherein the antifreeze proteins or ice recrystallization inhibition proteins comprise at least 11 amino acids.

6. The electrowetting optical device of any one of claims 1-5, wherein the conductive liquid comprises from about 1 x10 ¹⁰ % mol/mol to about 40 % mol/mol of the biological compound.

7. The electrowetting optical device of any one of claims 1-6, wherein the conductive liquid comprises from about 1 x10 ¹⁰ % mol/mol to about 30 % mol/mol of the biological compound.

8. The electrowetting optical device of any one of claims 1-7, wherein the conductive liquid comprises from about 1 x10 ¹⁰ % mol/mol to about 20 % mol/mol of the biological compound.

9. The electrowetting optical device of any one of claims 1-8, wherein the conductive liquid comprises from about 1 x10 ¹⁰ % mol/mol to about 10 % mol/mol of the biological compound.

10. The electrowetting optical device of any one of claims 1 -9, wherein the conductive liquid comprises from about 1x10 ¹⁰ % mol/mol to about 1 % mol/mol of the biological compound.

1 1. The electrowetting optical device of any one of claims 1-10, wherein the conductive liquid further comprises one or more salts.

12. The electrowetting optical device of claim 11 , wherein the salts comprise one or more halide salts.

13. The electrowetting optical device of claim 12, wherein the halide salts are selected from the group consisting of bromide, fluoride, iodide salts, and combinations thereof.

14. The electrowetting optical device of any one of claims 1-13, wherein the conductive liquid further comprises one or more preservatives or biocidal compounds.

15. The electrowetting optical device of claim 14, wherein the biocidal compounds comprise methylchloroisothiazolinone.

16. A conductive liquid comprising:

a polar liquid, and

a biological compound that decrease a freezing point of the polar liquid.

17. The conductive liquid of claim 16, wherein a ratio of a viscosity (cP) of the conductive liquid between -20 °C and 60 °C is less than about 9.

18. The conductive liquid of any one of claims 16-17, wherein the biological compound comprises antifreeze proteins (AFPs) or ice recrystallization inhibition proteins (IRIPs).

19. The conductive liquid of claim 18, wherein the antifreeze proteins (AFPs) or ice recrystallization inhibition proteins (IRIPs) comprise at least 8 amino acids.

20. The conductive liquid of claim 18, wherein the antifreeze proteins (AFPs) or ice recrystallization inhibition proteins (IRIPs) comprise at least 1 1 amino acids.

21. The conductive liquid of any one of claims 16-20, wherein the conductive liquid comprises from about 1x10 ¹⁰ % mol/mol to about 40 % mol/mol of the biological compound.

22. The conductive liquid of any one of claims 16-21 , wherein the conductive liquid comprises from about 1x10 ¹⁰ % mol/mol to about 30 % mol/mol of the biological compound.

23. The conductive liquid of any one of claims 16-22, wherein the conductive liquid comprises from about 1x10 ¹⁰ % mol/mol to about 20 % mol/mol of the biological compound.

24. The conductive liquid of any one of claims 16-23, wherein the conductive liquid comprises from about 1x10 ¹⁰ % mol/mol to about 10 % mol/mol of the biological compound.

25. The conductive liquid of any one of claims 16-24, wherein the conductive liquid comprises from about 1x10 ¹⁰ % mol/mol to about 1 % mol/mol of the biological compound.

26. The conductive liquid of any one of claims 16-25, wherein the conductive liquid further comprises salts.

27. The conductive liquid of any one of claims 16-26, wherein the salts comprise halide salts.

28. The conductive liquid of claim 27, wherein the halide salts are selected from the group consisting of bromide, fluoride, iodide salts, and combinations thereof.

29. The conductive liquid of any one of claims 16-28, wherein the conductive liquid further comprises preservatives or biocidal compounds.

30. The conductive liquid of claims 29, wherein the biocidal compounds comprise methylchloroisothiazolinone.

31 . The conductive liquid of any one of claims 16-30, wherein the conductive liquid is aqueous liquid.

32. A method of decreasing a freezing point of a conductive liquid in a liquid lens, the method comprising: adding a biological compound to a conductive liquid, thereby decreasing the freezing point of the conductive liquid in the presence of the biological compound.

33. The method of claim 32, further comprising stabilizing the biological compound by adding preservatives or biocidal compounds.

34. The method of claim 33, wherein the biocidal compounds comprise methylchloroisothiazolinone.

35. The method of any one of claims 32-34, wherein the biological compound comprises antifreeze proteins (AFPs) or ice recrystallization inhibition proteins (IRIPs).

36. The method of any one of claims 32-35, wherein a ratio of a viscosity (cP) of the conductive liquid between -20 °C and 60 °C is less than about 9.

37. The method of any one of claims 32-36, wherein a ratio of a viscosity (cP) of the conductive liquid between -20 °C and 60 °C is less than about 8.