阅读说明：本技术 用于红外液体透镜设计的低熔点离子液体 (Low-melting-point ionic liquid for infrared liquid lens design ) 是由 B·J-B·F·博格 于 2020-01-23 设计创作，主要内容包括：一种液体透镜,其可包括形成腔体的透镜主体,在所述腔体中设置有导电液体和绝缘液体,导电液体与绝缘液体基本不混溶,以在导电液体与绝缘液体之间限定界面。导电液体可包括二氰胺阴离子和阳离子抗衡离子的离子化合物,或者三氰基甲根阴离子和阳离子抗衡离子的离子化合物,二氰胺阴离子具有示出的式,三氰基甲根阴离子具有示出的式,并且阳离子抗衡离子是咪唑鎓、吡咯烷鎓、哌啶鎓、磷鎓、吡啶鎓、吡咯啉鎓或锍阳离子中的一种。导电液体的离子化合物尤其可以是二氰胺N-甲基-N-乙基吡咯烷鎓,二氰胺1-乙基-3-甲基咪唑鎓,三氰基甲烷化1-丁基-1-甲基吡咯烷鎓,或者三氰基甲烷化1-乙基-3-甲基咪唑鎓。对于波长为1550nm的电磁波,导电液体在1mm的厚度内可以具有至少50％的透射率。(A liquid lens may include a lens body forming a cavity in which a conductive liquid and an insulating liquid are disposed, the conductive liquid being substantially immiscible with the insulating liquid to define an interface between the conductive liquid and the insulating liquid. The conductive liquid may include an ionic compound of dicyanamide anions having the formula shown and cationic counterions, or tricyanomethane anions having the formula shown and cationic counterions that are one of imidazolium, pyrrolidinium, piperidinium, phosphonium, pyridinium, pyrrolinium, or sulfonium cations. The ionic compound of the electrically conductive liquid may be, in particular, dicyanamide N-methyl-N-ethylpyrrolidinium, dicyanamide 1-ethyl-3-methylimidazolium, tricyanomethane 1-butyl-1-methylpyrrolidinium or tricyanomethane 1-ethyl-3-methylimidazolium. For electromagnetic waves having a wavelength of 1550nm, the conductive liquid may have a transmittance of at least 50% within a thickness of 1 mm.)

1. An electrically conductive liquid, comprising:

an ionic compound comprising a dicyanamide anion and a cationic counterion, the dicyanamide anion having the general formula:

and the cationic counterion is one of an imidazolium, pyrrolidinium, piperidinium, phosphonium, pyridinium, pyrrolinium, or sulfonium cation.

2. The conductive liquid of claim 1, wherein the conductive liquid is in a liquid phase between-20 degrees celsius and 70 degrees celsius.

3. The conductive liquid of claim 1, wherein the conductive liquid has a transmittance of at least 50% within a thickness of 1mm for electromagnetic waves having a wavelength of 1550 nm.

4. The conductive liquid of claim 1, wherein the cationic counterion is an imidazolium cation having the general formula:

wherein R is hydrogen or alkyl, and R' is hydrogen or any organic group.

5. The conductive liquid according to claim 4, wherein the imidazolium cation is one of 1-ethyl-3-methylimidazolium cation, 1-allyl-3-methylimidazolium, 1-benzyl-3-methylimidazolium, 1-butyl-3-methylimidazolium, or 1-hexyl-3-methylimidazolium.

6. The conductive liquid according to claim 5, wherein the imidazolium cation is a 1-ethyl-3-methylimidazolium cation.

7. The conductive liquid of claim 1, wherein the cationic counterion is a pyrrolidinium cation having the general formula:

wherein R is hydrogen or alkyl, and R' is hydrogen or any organic group.

8. The conductive liquid according to claim 7, wherein the pyrrolidinium cation is one of an N-ethyl-N-methylpyrrolidinium cation or a 1-butyl-1-methylpyrrolidinium cation.

9. The conductive liquid according to claim 8, wherein the pyrrolidinium cation is an N-ethyl-N-methylpyrrolidinium cation.

10. An electrically conductive liquid, comprising:

an ionic compound comprising a tricyanomethane anion and a cationic counterion, the tricyanomethane anion having the general formula:

and the cationic counterion is one of an imidazolium, pyrrolidinium, piperidinium, phosphonium, pyridinium, pyrrolinium, or sulfonium cation.

11. The conductive liquid of claim 10, wherein the conductive liquid is in a liquid phase between-20 degrees celsius and 70 degrees celsius.

12. The conductive liquid of claim 10, wherein the conductive liquid has a transmittance of at least 50% within a thickness of 1mm for electromagnetic waves having a wavelength of 1550 nm.

13. The conductive liquid of claim 10, wherein the cationic counterion is an imidazolium cation having the general formula:

wherein R is hydrogen or alkyl, and R' is hydrogen or any organic group.

14. The conductive liquid according to claim 13, wherein the imidazolium cation is one of 1-ethyl-3-methylimidazolium cation, 1-allyl-3-methylimidazolium, 1-benzyl-3-methylimidazolium, 1-butyl-3-methylimidazolium, or 1-hexyl-3-methylimidazolium.

15. The conductive liquid according to claim 14, wherein the imidazolium cation is a 1-ethyl-3-methylimidazolium cation.

16. The conductive liquid of claim 10, wherein the cationic counterion is a pyrrolidinium cation having the general formula:

wherein R is hydrogen or alkyl, and R' is hydrogen or any organic group.

17. The conductive liquid of claim 16, wherein the pyrrolidinium cation is one of an N-ethyl-N-methylpyrrolidinium cation or a 1-butyl-1-methylpyrrolidinium cation.

18. The conductive liquid according to claim 17, wherein the pyrrolidinium cation is an N-ethyl-N-methylpyrrolidinium cation.

19. A liquid lens, comprising:

a lens body comprising a cavity; and

a conductive liquid and an insulating liquid disposed within the cavity, the conductive liquid being substantially immiscible with the insulating liquid, thereby defining an interface between the conductive liquid and the insulating liquid;

wherein the conductive liquid comprises any one of an ionic compound of dicyanamide anion and cationic counter ion or an ionic compound of tricyanomethyl anion and cationic counter ion, the dicyanamide anion having the following general formula:

the tricyanomethane anion has the general formula:

and the cationic counterion is one of an imidazolium, pyrrolidinium, piperidinium, phosphonium, pyridinium, pyrrolinium, or sulfonium cation.

20. The liquid lens according to claim 19, wherein the conductive liquid is in a liquid phase between-20 degrees celsius and 70 degrees celsius.

21. The liquid lens of claim 19Wherein the difference between the density of the conductive liquid and the density of the insulating liquid is 0.10g/cm at 20 deg.C³Within.

22. The liquid lens according to claim 19, wherein the cationic counterion is one of 1-ethyl-3-methylimidazolium cation, 1-allyl-3-methylimidazolium cation, 1-benzyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-hexyl-3-methylimidazolium cation, 1-ethyl-3-methylimidazolium cation, N-ethyl-N-methylpyrrolidinium cation, 1-butyl-1-methylpyrrolidinium cation, or trihexyltetradecylphosphonium cation.

23. The liquid lens according to claim 19, wherein the ionic compound of the conductive liquid is dicyanamide N-ethyl-N-methylpyrrolidinium.

24. The liquid lens according to claim 19, wherein the ionic compound of the conductive liquid is dicyanamide 1-ethyl-3-methylimidazolium.

25. The liquid lens according to claim 19, wherein the ionic compound of the electrically conductive liquid is tricyanomethane 1-butyl-1-methylpyrrolidinium.

26. The liquid lens according to claim 19, wherein the ionic compound of the electrically conductive liquid is tricyanomethane 1-ethyl-3-methylimidazolium.

27. The liquid lens according to claim 19, wherein the conductive liquid has a transmittance of at least 50% within a thickness of 1mm for an electromagnetic wave having a wavelength of 1550 nm.

28. The liquid lens according to claim 19, wherein the conductive liquid has a transmittance of at least 90% for electromagnetic waves having a wavelength of 1550 nm.

29. The liquid lens according to claim 19, wherein the ionic compound comprises at least 97 wt% of the total weight of the electrically conductive liquid.

30. The liquid lens of claim 19, wherein:

the insulating liquid comprises dodecane, (25-35% nonafluorohexylmethylsiloxane) (65-75% dimethylsiloxane) copolymer, bis (nonafluorohexyl) tetramethyldisiloxane and polydimethylsiloxane; and is

The ionic compound of the conductive liquid is tricyanomethane 1-butyl-1-methylpyrrolidinium.

31. The liquid lens of claim 19, wherein:

the insulating liquid comprises dodecane, (25-35% nonafluorohexylmethylsiloxane) (65-75% dimethylsiloxane) copolymer, bis (nonafluorohexyl) tetramethyldisiloxane, hexamethyldigermane and hexaethyldigermane; and is

The ionic compound of the conductive liquid is dicyanamide 1-ethyl-3-methylimidazolium.

2. Field of the invention

The present disclosure relates generally to liquid lenses. More particularly, the present disclosure relates to the composition of conductive liquids for liquid lenses that transmit a high percentage of incident electromagnetic waves having wavelengths in the infrared portion of the electromagnetic spectrum.

3. Background of the invention

A liquid lens is a type of variable focus lens which generally comprises a cavity, and in which a conductive liquid and an insulating liquid are disposed. The liquids are immiscible with each other and have different refractive indices so that the interface between the liquids (meniscus) forms a lens. The chamber contains an electrode. The electrodes may manipulate the shape of the lens based on the electrowetting principle. For example, a voltage may be applied between the conductive liquid and the cavity surface to increase or decrease the wettability of the surface with respect to the conductive liquid and to change the shape of the interface. Changing the shape (e.g., curvature) of the interface changes the focal length or focus of the lens.

To date, conductive liquids generally comprise an ionic compound dissolved in water or another polar non-ionic solvent, wherein the ionic compound separates into the corresponding cation and anion, thus forming a conductive liquid. The insulating liquid is typically an oil, an alkane or a mixture of alkanes. The presence of one or more hydroxyl groups (-OH) in the liquid normally used as the conducting liquid may advantageously render the conducting liquid immiscible with typical liquids used for insulating liquids.

In order for the liquid lens to operate optimally for the required application, both the conducting liquid and the insulating liquid should be transparent to the wavelength of the incident electromagnetic wave that is desired to be sensed. In other words, the conducting liquid and the insulating liquid should not absorb the wavelength of the incident electromagnetic wave in question. Absorbing the wavelength of the incident electromagnetic wave in question prevents the wavelength of the incident electromagnetic wave in question from being transmitted through the liquid lens. Most applications where liquid lenses are employed are for sensing (and imaging) the visible portion of the electromagnetic spectrum at wavelengths between 400nm and 700 nm. The conductive liquids typically used for these applications are highly transparent to incident electromagnetic waves having wavelengths within this range.

However, the conductive liquids typically used for liquid lenses may make the liquid lenses unsuitable for applications intended to sense incident electromagnetic waves having wavelengths longer than those in the visible portion of the electromagnetic spectrum (e.g., electromagnetic waves in the infrared portion of the electromagnetic spectrum).

Therefore, there is a need for a conductive liquid that is sufficiently transparent to electromagnetic waves having a longer wavelength than the visible region and that is also compatible with commonly used insulating liquids.

Disclosure of Invention

The present disclosure meets these needs because it was discovered that dicyanamide anions and tricyanomethyl anions can form ionization with counter cationsA compound, the ionic compound: (1) has a melting point of-20 ℃ or less; (2) the density at 20 ℃ is closer to 1.0g/cm³Therefore, the insulating liquid is easier to pair with the common insulating liquid; (3) immiscible with common insulating liquids despite the absence of hydroxyl groups; and (4) is substantially transparent to electromagnetic waves having a longer wavelength than the visible region. Thus, such ionic compounds of dicyanamide anions or tricyanomethane anions with cationic counterions form suitable electrically conductive liquids for liquid lenses for applications intended for sensing electromagnetic waves having wavelengths in the infrared region.

According to the 1 st aspect of the present disclosure, a conductive liquid for a liquid lens includes: an ionic compound of a dicyanamide anion and a cationic counterion, the dicyanamide anion having the general formula:

and the cationic counterion is one of an imidazolium, pyrrolidinium, piperidinium, phosphonium, pyridinium, pyrrolinium, sulfonium cation, or any other cation that provides the desired properties. In one embodiment, the conductive liquid is in a liquid phase between-20 degrees Celsius and 70 degrees Celsius. In one embodiment, the conductive liquid has a transmittance of at least 50% (in some embodiments, including at least 85%) over a thickness of 1mm for electromagnetic waves having a wavelength between 1400nm and 1550 nm. In one embodiment, the cationic counterion is an imidazolium cation having the general formula:

wherein R is hydrogen or alkyl, and R' is hydrogen or any organic group. In one embodiment, the imidazolium cation is one of 1-ethyl-3-methylimidazolium cation, 1-allyl-3-methylimidazolium, 1-benzyl-3-methylimidazolium, 1-butyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium. In one embodiment, the imidazolium cation is a 1-ethyl-3-methylimidazolium cation. In one embodiment, the cationic counterion is a pyrrolidinium cation having the general formula:

wherein R is hydrogen or alkyl, and R' is hydrogen or any organic group. In one embodiment, the pyrrolidinium cation is one of an N-ethyl-N-methylpyrrolidinium cation, a 1-butyl-1-methylpyrrolidinium cation. In one embodiment, the pyrrolidinium cation is an N-ethyl-N-methylpyrrolidinium cation. In one embodiment, the conductive liquid consists of one of the aforementioned ionic compounds, or a mixture of more than one of the aforementioned ionic compounds. In one embodiment, the conductive liquid comprises a mixture of one or more of the foregoing ionic compounds with another liquid. In one embodiment, the conductive liquid comprises a mixture of one or more of the foregoing ionic compounds with another liquid, wherein the one or more of the foregoing ionic compounds comprises at least 50% by weight of the conductive liquid, at least 60% by weight of the conductive liquid, at least 70% by weight of the conductive liquid, at least 80% by weight of the conductive liquid, at least 90% by weight of the conductive liquid, or at least 99% by weight of the conductive liquid.

According to the 2 nd aspect of the present disclosure, a conductive liquid for a liquid lens includes: an ionic compound of a tricyanomethane anion and a cationic counterion, the tricyanomethane anion having the general formula:

and the cationic counterion is one of an imidazolium, pyrrolidinium, piperidinium, phosphonium, pyridinium, pyrrolinium, sulfonium cation, or any other cation that provides the desired properties. In one embodiment, the conductive liquid is in a liquid phase between-20 degrees Celsius and 70 degrees Celsius. In one embodiment, the conductive liquid has a transmittance of at least 50% (in some embodiments, including at least 85%) over a thickness of 1mm for electromagnetic waves having a wavelength between 1400nm and 1550 nm. In one embodiment, the cationic counterion is an imidazolium cation having the general formula:

wherein R is hydrogen or alkyl, and R' is hydrogen or any organic group. In one embodiment, the imidazolium cation is one of 1-ethyl-3-methylimidazolium cation, 1-allyl-3-methylimidazolium, 1-benzyl-3-methylimidazolium, 1-butyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium. In one embodiment, the imidazolium cation is one of 1-ethyl-3-methylimidazolium cation, 1-allyl-3-methylimidazolium, 1-benzyl-3-methylimidazolium, 1-butyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium. In one embodiment, the cationic counterion is a pyrrolidinium cation having the general formula:

wherein R is hydrogen or alkyl, and R' is hydrogen or any organic group. In one embodiment, the pyrrolidinium cation is one of an N-ethyl-N-methylpyrrolidinium cation, a 1-butyl-1-methylpyrrolidinium cation. In one embodiment, the pyrrolidinium cation is an N-ethyl-N-methylpyrrolidinium cation. In one embodiment, the conductive liquid comprises a mixture of one or more of the foregoing ionic compounds with another liquid, wherein the one or more of the foregoing ionic compounds comprises at least 50% by weight of the conductive liquid, at least 60% by weight of the conductive liquid, at least 70% by weight of the conductive liquid, at least 80% by weight of the conductive liquid, at least 90% by weight of the conductive liquid, or at least 99% by weight of the conductive liquid.

According to the 3 rd aspect of the present disclosure, a liquid lens includes: a lens body forming a cavity retaining a conductive liquid and an insulating liquid, the conductive liquid being immiscible with the insulating liquid and forming an interface between the conductive liquid and the insulating liquid; the conductive liquid comprises an ionic compound of dicyanamide anions and cationic counterions, or tricyanomethane anions and cationic counterions, the dicyanamide anions having the following general formula:

the tricyanomethane anion has the general formula:

and the cationic counterion is one of an imidazolium, pyrrolidinium, piperidinium, phosphonium, pyridinium, pyrrolinium, or sulfonium cation. In one embodiment, the conductive liquid is in a liquid phase between-20 degrees Celsius and 70 degrees Celsius. In one embodiment, the conducting liquid has a density and the insulating liquid has a density, the density of the conducting liquid and the density of the insulating liquid differing by 0.10g/cm at 20 degrees celsius³Within. In one embodiment, the cationic counterion is one of a 1-ethyl-3-methylimidazolium cation, a 1-allyl-3-methylimidazolium cation, a 1-benzyl-3-methylimidazolium cation, a 1-butyl-3-methylimidazolium cation, a 1-hexyl-3-methylimidazolium cation, a 1-ethyl-3-methylimidazolium cation, an N-ethyl-N-methylpyrrolidinium cation, a 1-butyl-1-methylpyrrolidinium cation, or a trihexyltetradecylphosphonium cation. In one embodiment, the ionic compound of the conductive liquid is dicyanamide N-methyl-N-ethylpyrrolidinium. In one embodiment, the ionic compound of the conductive liquid is dicyanamide 1-ethyl-3-methylimidazolium.In one embodiment, the ionic compound of the electrically conductive liquid is tricyanomethane 1-butyl-1-methylpyrrolidinium. In one embodiment, the ionic compound of the conductive liquid is tricyanomethane 1-ethyl-3-methylimidazolium. In one embodiment, the conductive liquid has a transmittance of at least 50% (including at least 80% in some embodiments, and at least 85% in some embodiments) over a thickness of 1mm for electromagnetic waves having a wavelength between 1400nm and 1550 nm.

Additional features and advantages are 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 and the claims.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and are intended to provide an overview or framework for understanding the nature and character of the claims.

Drawings

FIG. 1 is a plan cross-sectional view of some embodiments of a liquid lens that may employ a conducting liquid and an insulating liquid that remain separated at an interface, and the interface acts as a lens to manipulate (e.g., focus) electromagnetic waves;

FIG. 2A is a cross-sectional perspective view of further embodiments of a liquid lens that may employ a conducting liquid and an insulating liquid that are kept separate at an interface, and the interface acts as a lens to manipulate (e.g., focus) electromagnetic waves;

FIG. 2B is a plan cross-sectional view of the liquid lens embodiment of FIG. 2A, with a conductive liquid and an insulating liquid disposed in the liquid lens and kept separate at the interface, which acts as a lens to manipulate (e.g., focus) electromagnetic waves;

FIG. 3 is a graph of the change in contact angle as a function of applied voltage (a) as voltage is increased and (b) as voltage is decreased for dicyanamide 1-ethyl-3-methylimidazolium (as a conductive liquid) and diphenyldimethylgermane (as an insulating liquid);

FIG. 4A is a graph of percent transmission of an incident electromagnetic wave through ethylene glycol as a function of wavelength of the electromagnetic wave;

FIG. 4B is a graph of the percent transmission of an incident electromagnetic wave through dicyanamide 1-ethyl-3-methylimidazolium as a function of the wavelength of the electromagnetic wave;

FIG. 5 is a graph of percent transmission of incident electromagnetic waves through several liquid lenses, each lens employing a different conducting liquid and insulating liquid, illustrating the improved transmission of electromagnetic waves having wavelengths in the infrared portion when the conducting liquid includes an ionic compound having either tricyanomethane anions or dicyanamide anions; and is

Fig. 6 is a graph of optical power as a function of voltage (electrowetting curve) and wavefront error as a function of voltage for a liquid lens containing a conductive liquid of the present disclosure.

Detailed Description

Exemplary liquid lens Structure

Referring now to FIG. 1, a simplified cross-sectional view of an exemplary liquid lens 10 is illustrated. The liquid lens 10 includes a lens body 12. The lens body 12 forms a cavity 14. The cavity 14 retains a conductive liquid 16 and an insulating liquid 18. The conducting liquid 16 and the insulating liquid 18 are immiscible, and therefore an interface 20 is formed between the conducting liquid 16 and the insulating liquid 18. Since the conducting liquid 16 and the insulating liquid 18 have different refractive indices, the interface 20 operates as a lens.

In some embodiments, the multiple layers cooperate to form the lens body 12 and thus the cavity 14, with the conductive liquid 16 and the insulating liquid 18 disposed within the cavity 14. For example, in the illustrated embodiment, the lens body 12 includes first and second outer layers 22, 24, and an intermediate layer 26 disposed between the first and second outer layers 22, 24. The middle layer 26 may include a hole 28, the hole 28 being formed through the middle layer 26 to define a portion of the cavity 14. The first window 30 is disposed at the first outer layer 22. A second window 32 is provided at the second outer layer 24.

The first window 30 and the second window 32 are sufficiently transparent to enable passage of an electromagnetic wave 34 having a wavelength 36 desired to be sensed through the liquid lens 10. An incident electromagnetic wave 34 having a wavelength 36 enters the liquid lens 10 through the first window 30, is manipulated at the interface 20 between the conducting liquid 16 and the insulating liquid 18, and then exits the liquid lens 10 through the second window 32. In some embodiments, the first outer layer 22 and/or the second outer layer 24 are all sufficiently transparent to the wavelength 36 of the electromagnetic wave 34 desired to be sensed. Since the electromagnetic waves 34 can pass through the holes 28 in the intermediate layer 26, the intermediate layer 26 need not be transparent to the wavelength 36 of the electromagnetic waves 34 desired to be sensed, but the intermediate layer 26 can be transparent to that wavelength 36.

In some embodiments, the outer surface 38 of the first outer layer 22 and/or the outer surface 40 of the second outer layer 24 are each substantially planar. Thus, even if the liquid lens 10 operates as a lens (e.g., by refracting electromagnetic waves 34 passing through the interface 20), the outer surfaces 38, 40 of the liquid lens 10 may be flat, rather than curved like the outer surfaces of some fixed lenses. In other embodiments, the outer surface 38 of the first outer layer 22 and/or the outer surface 40 of the second outer layer 24 may be curved (e.g., concave or convex), respectively. Thus, the liquid lens 10 may comprise an integrated stationary lens.

The liquid electrode 10 also includes a common electrode 42 in electrical communication with the conductive liquid 16. Furthermore, the liquid lens 10 comprises one or more drive electrodes 44, which may be arranged near or at the side walls of the cavity 14 and which are isolated from the conducting liquid 16 and the insulating liquid 18. Different voltages may be applied to the common electrode 42 and the one or more drive electrodes 44 to change the shape of the interface 20 as described herein through a phenomenon known as electrowetting. In other words, the voltage may be manipulated to increase or decrease the wettability of the surface 46 of the cavity 14 with respect to the conductive liquid 16 and to change the shape or position of the interface 20. In some embodiments, the voltage is manipulated to change the shape of the interface 20, which changes the focal length or focus of the liquid lens 10. Such a change in focal length enables the liquid lens 10 to perform an auto-focus function, for example. In other embodiments, the voltage is manipulated to change the position (e.g., tilt) of the interface 20 relative to the optical axis 48 of the liquid lens 10. For example, such a tilt of the interface 20 enables the liquid lens 10 to perform an Optical Image Stabilization (OIS) function. Adjustment of the interface 20 may be accomplished without physical movement of the lens body 12 relative to the image sensor, the stationary lens or lens stack, the housing, or other components of the device in which the liquid lens 10 may be contained. In order to provide a wide range of focal lengths and tilt angles, it may be beneficial to have a significant difference in optical refractive index between the conducting liquid 16 and the insulating liquid 18. In some embodiments, the conducting liquid 16 and the insulating liquid 18 have substantially the same density, which may help to avoid that the shape or tilt of the interface 20 changes due to a change in the physical orientation of the lens body 12 (e.g., due to gravity).

In some embodiments of liquid lens 10, chamber body 14 includes a headspace 50 and a base portion 52. For example, the aperture 28 in the intermediate layer 26 of the liquid lens 10 may define a base portion 52 of the cavity 14. The recess 54 in the first outer layer 22 of the liquid lens 10 may define a headspace 50 of the cavity 14, and the headspace 50 may be disposed outside of the hole 28 of the intermediate layer 26, as described herein. In the illustrated embodiment, at least a portion of the electrically conductive liquid 16 is disposed in a headspace 50 of the chamber 14, and the insulating liquid 18 is disposed within a base portion 52 of the chamber 14. Substantially all or a portion of the insulating liquid 18 may be disposed within the base portion 52 of the cavity 14. In some embodiments, the perimeter 56 of the interface 20 contacts the surface 46 of the cavity 14 within the base portion 52 of the cavity 14.

In the illustrated embodiment, the cavity 14 (and more specifically, the base portion 52 of the cavity 14) is tapered such that the cross-sectional area of the cavity 14 decreases along the optical axis 48 in a direction from the first window 30 to the second window 32. For example, the base portion 52 of the cavity 14 has a narrow end 58 and a wide end 60. The terms "narrow" and "wide" are relative terms, meaning that the narrow end 58 is narrower than the wide end 60. Such tapering of the cavity 14 may help maintain alignment of the interface 20 between the conducting liquid 16 and the insulating liquid 18 along the optical axis 48. In other embodiments, the cavity 14 may be tapered such that the cross-sectional area of the cavity 14 increases along the optical axis 48 in a direction from the first window 30 toward the second window 32, or the cavity 14 is not tapered such that the cross-sectional area of the cavity 14 remains substantially constant along the optical axis 48.

In the illustrated embodiment, the liquid lens 10 further includes a conductive layer 62. At least a portion of the conductive layer 62 faces the cavity 14. The conductive layer 62 may be a conductive coating that is applied to the intermediate layer 26 before the first and/or second outer layers 22, 24 are bonded to the intermediate layer 26. The conductive layer 62 may comprise a metallic material, a conductive polymer material, another suitable conductive material, or a combination thereof. The conductive layer 62 may be formed of a single layer or multiple layers, some or all of which are conductive. In some embodiments, the conductive layer 62 defines the common electrode 42 and/or one or more drive electrodes 44. For example, the conductive layer 62 may be applied to substantially the entire outer surface of the intermediate layer 26 before the first outer layer 22 and/or the second outer layer 24 are bonded to the intermediate layer 26. After the conductive layer 62 is applied to the intermediate layer 26, the conductive layer 62 may be divided into various conductive elements (e.g., the common electrode 42 and/or the drive electrode 44). In some embodiments, the conductive layer 62 is segmented at the scribe lines 64 to isolate (e.g., electrically isolate) the common electrode 42 and the drive electrode 44 from each other. In some embodiments, scribe line 64 is a gap in conductive layer 62. For example, the scribe lines 64 may be gaps having a width of about 5 μm, about 10 μm, about 15 μm, about 20 μm, about 25 μm, about 30 μm, about 35 μm, about 40 μm, about 45 μm, about 50 μm, or any range defined by the listed values.

In the illustrated embodiment, the liquid lens 10 further comprises an insulating layer 66, the insulating layer 66 being disposed on the drive electrode 44 layer and facing the cavity 14. For example, to form the insulating layer 66, an insulating coating may be applied over the conductive layer 62 and the second window 32 after the second outer layer 24 and the intermediate layer 26 are bonded together, but before the first outer layer 22 and the intermediate layer 26 are bonded. Accordingly, the insulating layer 66 covers at least a portion of the conductive layer 62 at the cavity 14 and the second window 32. The insulating layer 66 is sufficiently transparent to the wavelength 36 of the electromagnetic waves 34 intended to pass through the liquid lens 10 for sensing. In other embodiments, to form the insulation layer 66, an insulation coating is applied to the intermediate layer 26 before the first outer layer 22 and/or the second outer layer 24 are bonded to the intermediate layer 26.

In the illustrated embodiment of the liquid lens 10, the insulating layer 66 covers a portion of the drive electrode 44 that would otherwise be exposed to the cavity 14 to isolate the conductive liquid 16 and the insulating liquid 18 from the drive electrode 44. However, in the illustrated embodiment, the insulating layer 66 does not cover at least a portion of the common electrode 42 exposed to the cavity 14. Thus, the common electrode 42 is in electrical communication with the conductive liquid 16.

Alternative exemplary lens construction

Referring now to fig. 2A and 2B, a simplified cross-sectional view of another exemplary liquid lens 200 is illustrated. The liquid lens 200 includes: a lens body 201 comprising a cover portion 202, a liner 204, a base portion 206, a window 210 and a window 238. The lens body 201 forms a cavity 213. The cavity 213 retains the conductive liquid 16 and the insulating liquid 18.

The cover portion 202 is placed over the base portion 206 but separated from the base portion 206 by the liner 204. The lid portion 202 includes a metal lid 208 formed from a conductive sheet of metal, to which metal lid 208 a disc-shaped glazing 210 is sealed, for example by a seal 212 formed from an adhesive. The cover has a circular opening 214 that allows the electromagnetic waves 34 to pass through to the glass window 210. The circular opening 214 is centered on the optical axis Δ of the liquid lens 200 and is on a plane perpendicular to the optical axis Δ.

Moving outwardly from the optical axis, the metal cover 208 includes an annular flat portion 216 that surrounds the opening 214 and is preferably perpendicular to the optical axis Δ. A first location of the inner surface of portion 216 contacts the outer surface of window 210 and a radially outer portion of the inner surface of portion 216 contacts window 210 and the outer edge of seal 212. The outer edge of the portion 216 is bent to form an edge 218, which edge 218 extends substantially at right angles parallel to the optical axis Δ and extends from the portion 216 towards the base portion 206. The rim 218 also preferably contacts the seal 212. According to this embodiment, starting from the edge 218, its essentially "S" -shaped (e.g. corrugated) portion 220 extends away from the optical axis Δ, so that the edge 218 is connected to a further annular flat portion 222, which annular flat portion 222 preferably extends at least substantially perpendicularly to the optical axis Δ. The "S" shaped portion 220 is designed to allow some movement of the window 210 when pressure is applied by the fluid inside the liquid lens 200, but only in a direction parallel to the optical axis Δ.

The right angle bend from section 222 connects to an annular rim section 224 extending at least substantially parallel to the optical axis Δ, which forms the outer rim of liquid lens 200 and surrounds gasket 204 and base section 206. The end of the portion 224 forming the outer edge of the sheet metal of the metal cover 208 is preferably bent inwardly at the region 226 towards the optical axis Δ by crimping so that it holds the gasket 204 and base portion 206 in place.

The liner 204 may be formed of a polymer and may be annular and substantially "L" shaped in cross-section such that an outer surface of a first side or leg 228 of the "L" contacts and is parallel to an inner surface of the annular flat portion 222 of the metal cap 208 and an outer surface of a second side or leg 230 of the "L" contacts and is parallel to an inner surface of the rim portion 224 of the metal cap 208, thus increasing the contact surface. Other shapes are possible for the pad 204. For example, in some embodiments, the pad 204 may include only the first limbs 228. The inner surfaces of the first leg 228 and the second leg 230 contact the surface of the base portion 206. The region 232 at the end of the second limb 230 is bent inward toward the optical axis Δ (thus becoming a bent portion 232) by the pressure applied by the crimped region 226 of the metal cover 208, and the inner surface of the gasket 204 at this time exerts pressure on the corner of the base portion 206 and holds it in place. The end surface 234 of the first limb 228 faces the optical axis Δ and is exposed to the inner chamber of the liquid lens 200.

The base portion 206 preferably includes a ring electrode 236, the ring electrode 236 being formed of an electrically conductive material, preferably a metal, to which a disk-shaped glass window 238 positioned substantially perpendicular to the optical axis Δ is adhered and sealed by a seal 240 (e.g., an adhesive or bonding agent). An opening 242 centered on the optical axis Δ is formed in the ring electrode 236 to allow light to pass through the glass window 238 to the liquid lens 200 or from the liquid lens 200 through the glass window 238. The glazing 238 is located on the outside of the opening 242. The ring electrode 236 is molded or machined in the shape of a ring having a plurality of surfaces and the surfaces are preferably rotationally symmetric with respect to the optical axis Δ, which will now be described in more detail.

The inner edge 244 of the annular electrode 236 surrounding the opening 242 is preferably a sloped surface, e.g., at about 45 degrees to the optical axis Δ, and faces upward toward the liquid lens 200. Adjacent and surrounding the inner edge 244 is an annular flat portion 246, which is also generally perpendicular to the optical axis Δ, and adjacent the annular flat portion 246 is another beveled edge 248, which also faces the liquid lens 200 and is generally parallel to the inner surface 244. Adjacent to and surrounding the beveled edge 248 is an annular flat surface 250, the inner portion of which is exposed to the inner chamber of the liquid lens 200 and the outer portion of which provides a first contact surface with the inner surface of the limb 228 of the gasket 204. Abutting the surface 250 is an edge surface 252, which is generally parallel to the optical axis Δ, the edge surface 252 preferably providing a second contact surface with the inner surface of the limb 230 of the pad 204. An annular flat outer surface 254 adjacent the edge surface 252 faces outwardly from the liquid lens 200 and extends back toward the optical axis Δ. The substantially right angle corner between the edge surface 252 and the outer surface 254 is the corner that preferably contacts the inner region of the gasket 204 that is bent by the crimped region 226 of the metal cover 208. Another surface 256 adjacent the outer surface 254 extends outwardly from the liquid lens 200 generally parallel to the optical axis Δ, and an annular surface 258 adjacent the surface 256 generally perpendicular to the optical axis Δ extends inwardly toward the optical axis Δ. A radially inwardly facing surface 260 extends adjacent annular surface 258 generally parallel to optical axis Δ and extends back toward the interior chamber of liquid lens 200. The surface 260 abuts an annular flat surface 262, the flat surface 262 also being substantially perpendicular to the optical axis Δ, which terminates at the inner edge 244 of the annular electrode 236. The radially inner portion of the annular flat surface 262 contacts the glass window 238, and the radially outer portion of the annular flat surface 262 contacts the seal 240, which holds the window 238 in place.

The ring electrode 236 preferably includes contact surfaces 260, 262 for receiving the window 238, an inner edge 244 for receiving the insulating liquid 18, a first contact surface 250 and a second contact surface 252 for contacting the inner surface of the gasket 204, and an angle between the surfaces 252 and 254 for contacting the curved portion 232 of the gasket 204, thereby holding the ring electrode 236 in place.

Although not shown in fig. 2A, it is shown in fig. 2B that the liquid lens 200 contains the conductive liquid 16 and the insulating liquid 18 within the cavity 213 formed between the windows 210 and 238. The insulating liquid 18 may be a dielectric positioned to cover the opening 242 of the ring electrode 236 on the surface of the glass window 238. The edge of the insulating liquid 18 preferably falls within a portion of the inner edge 244 of the ring electrode 236. The conductive liquid 16 fills the remaining volume of the cavity 213. Neither the conductive liquid 16 nor the insulating liquid 18 directly contacts the exposed surface of the ring electrode 236, which has been covered by an insulating layer, as explained in more detail below. The conductive liquid 16 exposed to the "S" shaped region 220 of the metal cover 208 of the cavity 213 is in electrical contact therewith.

In operation, a voltage (preferably an oscillating voltage) is applied between the ring electrode 236 and the metal cap 208, the metal cap 208 acting as a second electrode and being in contact with the conductive liquid 16. This voltage changes the curvature of the interface 20 between the conducting liquid 16 and the insulating liquid 18, since the electrowetting effect increases the ability of the inner edge 244 to be wetted by water. The conducting liquid 16 and the insulating liquid 18 have different refractive indices such that the electromagnetic wave 34 is refracted at the interface 20. The electromagnetic waves 34 pass through the windows 210 and 238 and through the interface 20 between the conducting liquid 16 and the insulating liquid 18.

An insulating layer, which is, for example, a polymer, is applied to the top and sides of the base portion 206, i.e., to the surfaces 252, 250, 248, 246, 244 and on the surface of the window 238 to ensure effective electrowetting. The polymeric soft coating 400 may be applied to the exposed inner surface of the metal cover 208 in contact with the liner 204, in other words, over the inner surfaces of the portions 224 and 222, and at least a portion of the interior of the "S" shaped portion 220. The liner 204 may be coated with a soft polymer coating 402 and 404 on the outer and inner surfaces, respectively. These are the areas that are in contact with the metal cover 208 and base 206, respectively. A polymer coating 406 may be applied to the outer edge surface 252 and the top surface 250 of the ring electrode 236 over the insulating layer (e.g., the surface in contact with the liner 204).

The liquid lens 10 and the liquid lens 200 are examples that provide a background for the novel conductive liquid 16 described herein and are not meant to limit the applicability of the novel conductive liquid 16 to liquid lenses having different structures and compositions. The novel conductive liquid 16 described herein can be advantageously used in any liquid lens structure.

Insulating layer

The insulating layer 66 of the liquid lens 10, and the insulating layers applied on the top and sides of the base portion 206, i.e. applied on the surfaces 252, 250, 248, 246, 244 of the liquid lens 200 and on the surface of the window 238 of the liquid lens 200, may be, for example:

silicone polymer PDSM;

amorphous fluoropolymers, e.g. from DuPontAF 1600 and AF 1601;

poly (arylene ether);

fluorinated poly (arylene ether);

a linear polymer of para-xylene, fluorinated or not, such as parylene, for example parylene C, parylene F or parylene AF-4, parylene VT-4, parylene N or parylene D;

amorphous fluoropolymers, e.g. from Asahi Glass Co

From Suwei (Solvay)A polymer;

aromatic vinyl siloxane polymers, for example, divinylsiloxane-benzocyclobutene (DVS-BCB) from Dow Chemical company (Dow Chemical);

diamond-like carbon (DLC);

poly (tetrafluoroethylene);

polyethylene;

polypropylene;

a fluorine-containing ethylene propylene polymer;

polynaphthalene;

fluorinated polynaphthalene; and

SiO-Silicone-like polymeric film_xC_yH_z。

Insulating liquid

In some embodiments, the conductivity of the insulating liquid 18 is less than 1x10^-8S/m, less than 1x10^-10S/m, or less than 1x10^-14And (5) S/m. The insulating liquid 18 may be an organic compound or an inorganic compound or a mixture thereof. Examples of such organic or inorganic compounds include hydrocarbons, Si-based monomers, oligomers and polymers, and mixtures thereof. Other examples include Ge-based monomers, oligomers and polymers, and Si-Ge-based monomers, oligomers and polymers.

The hydrocarbon may be linear, branched or contain one or more cyclic moieties which are saturated, unsaturated, or partially unsaturated. The hydrocarbon may have from about 8 to about 35 carbon atoms, alternatively from 10 to about 20 carbon atoms. The hydrocarbon may have a boiling point above 100 ℃. The hydrocarbons may include single hydrocarbons or petroleum distillates with freezing points below-20 ℃.

The hydrocarbon may include one or more unsaturations in the form of double and/or triple bonds. However, more than 2 or 3 double or triple bonds may increase the risk of decomposition upon exposure to ultraviolet radiation. In some embodiments, the hydrocarbon does not contain any double or triple bonds, in which case the hydrocarbon may be referred to herein as an alkane.

The hydrocarbon may also include one or more heteroatoms as substituents and/or groups of atoms or atoms that interrupt the hydrocarbon chain and/or rings. These heteroatoms include, but are not limited to, oxygen, sulfur, nitrogen, phosphorus, halogen atoms (primarily fluorine, chlorine, bromine, and/or iodine). It should be noted that the presence of one or more heteroatoms should not affect the immiscibility of the two fluids.

The insulating liquid 18 may be a mixture comprising more than 99.8% alkane. Such a mixture may contain aromatic groups and/or unsaturated moieties in a ratio of less than 1 wt% (e.g., less than about 0.5 wt%) of the insulating liquid 18. Mixtures of alkanes may include impurities that are present as by-products of alkane production (e.g., when they are obtained by distillation processes).

Some exemplary hydrocarbons for the insulating liquid 18 include: linear or branched alkanes, e.g. decane (C)₁₀H₂₂) Dodecane (C)₁₂H₂₄) Squalane (C)₃₀H₆₂) Etc.; alkanes containing one or more rings, e.g. tert-butylcyclohexane (C)₁₀H₂₀) Etc.; condensed ring systems, e.g. alpha-chloronaphthalene, alpha-bromonaphthalene, cis, trans-decalin (C)₁₀H₁₈) Etc.; mixtures of hydrocarbons, e.g. asV、P (ex xon Mobil), and the like, and mixtures thereof.

As mentioned, the insulating liquid 18 may comprise a silicon based compound. Such silicon-based compounds may include siloxanes of formula Ia, Ib, or Ic:

wherein R1, R2 and R' each independently represent alkyl, (hetero) aryl, (hetero) aralkyl, (hetero) aralkenyl or (hetero) aralkynyl, and n is comprised between about 1 and 20, or between 1 and 10 (e.g., 1, 2, 3, 4 or 5), and note that n is greater than 2 in formula Ic.

The silicon-based compound may include a silane of formula II:

wherein R1, R2, and R' are as defined above, and m is comprised between about 1 and about 20, or between about 1 and about 10 (e.g., 1, 2, or 3).

The silicon-based compound may include a monosilane of formula III:

wherein R1 and R2 are as defined above, and R3 and R4 each independently represent alkyl, (hetero) aryl, (hetero) aralkyl, (hetero) arylalkenyl or (hetero) arylalkynyl.

In the above formula: (1) alkyl means a straight or branched chain alkyl group having from about 1 to about 10 carbon atoms, or from about 1 to about 6 carbon atoms; alkyl groups may include methyl, ethyl, n-propyl, isopropyl; the alkyl group may be halogenated, and may include, for example, 1,1, 1-trifluoropropyl; (2) (hetero) aryl means an aromatic or heteroaromatic group containing from about 5 to about 12 atoms, which forms at least one (e.g. one) aromatic and/or heteroaromatic ring, which ring is optionally substituted with one or more halogen (e.g. 1, 2, 3 halogen atoms, e.g. fluorine, chlorine and/or bromine), and is optionally fused with one or more saturated, partially saturated or unsaturated ring systems; (hetero) aryl may include phenyl, naphthyl, bicyclo [4.2.0] octrienyl, optionally substituted with 1, 2, or 3 halogen atoms; (3) (hetero) aralkyl is as defined above for each of alkyl and (hetero) aryl; (hetero) aralkyl may include benzyl, phenethyl, optionally substituted with 1, 2 or 3 halogen atoms; and (4) (hetero) arylalkenyl and (hetero) arylalkynyl correspond to groups satisfying the following: wherein the (hetero) aryl moiety is as defined above and the alkenyl and alkynyl groups represent straight-chain or branched alkyl groups as defined above and further comprise one or more (e.g. one) double bonds or one or more (e.g. one) triple bonds, respectively.

Some exemplary silicon-based compounds for the insulating liquid 18 include hexamethyldisilazane, diphenyldimethylsilane, chlorophenyltrimethylsilane, phenyltrimethylsilane, phenethyltris (trimethylsiloxy) 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, and n-octyltris (trimethylsiloxy) silane.

The insulating liquid 18 may comprise one or more germane (Ge) -based species. Exemplary germanyl compounds include hexamethyldigermane, hexaethyldigermane, diphenyldimethylgermane, 1-naphthyltriethylgermane (1-naphthylltriethyngerane) and phenyltrimethylgermane.

The insulating liquid 18 may comprise at least one Si-based and/or Ge-based compound substituted with one or more phenyl groups and/or other groups, such as fluorinated or non-fluorinated alkyl groups (ethyl, n-propyl, n-butyl), linear or branched alkyl groups, chlorinated or brominated phenyl groups, benzyl groups, halobenzyl groups; or the insulating liquid 18 comprises a mixture of Si-and/or Ge-based compounds, wherein at least one of the compounds is substituted by one or more phenyl groups and/or other groups such as fluorinated or non-fluorinated alkyl (ethyl, n-propyl, n-butyl), linear or branched alkyl, chlorinated or brominated phenyl, benzyl, halobenzyl. Some specific examples include copolymers of bis (nonafluorohexyl) tetramethyldisiloxane and (25-35% nonafluorohexyl methylsiloxane) (65-75% dimethylsiloxane).

One exemplary insulating liquid 18 includes dodecane, nonafluorohexylmethylsiloxane/dimethylsiloxane copolymer, bis (nonafluorohexyl) tetramethyldisiloxane, and polydimethylsiloxane. Exemplary weight percentages by total weight include: dodecane (12-30%); (25-35% nonafluorohexylmethylsiloxane) (65-75% dimethylsiloxane) copolymer (15-63%); bis (nonafluorohexyl) tetramethyldisiloxane (15-60%); and polydimethylsiloxane (10-30%). Another exemplary insulating liquid 18 includes 1-naphthyl triethylgermane, n-octyltris (trimethylsiloxy) silane, and polyphenyl ether SANTOLIGHTAnother exemplary insulating liquid 18 includes dodecane, (25-35% nonafluorohexylmethylsiloxane) (65-75% dimethylsiloxane), bis (nonafluorohexyl) tetramethyldisiloxane, hexamethyldigermane, and hexaethyldigermane. Adjusting the weight percentages of the various components of the insulating liquid 18 affects the density, viscosity, and refractive index of the insulating liquid 18.

Conductive liquid

In some embodiments, the novel conductive liquids 16 of the present disclosure include ionic compounds of one or more of dicyanamide anions and tricyanomethane anions with cationic counterions. The dicyanamide anion is represented by formula IV:

the tricyanomethane anion is represented by formula V:

it has been found that ionic compounds comprising dicyanamide anions or tricyanomethane anions and cationic counterions, as compared to the common electrically conductive liquid 16 comprising hydroxyl groups: (1) more likely to have a melting point closer to-20 ℃ or lower; (2) more likely to have a density closer to 1.0g/cm at 20 deg.C³And thus more easily mated with the usual insulating liquid 18; (3) immiscible with the usual insulating liquid 18 despite the absence of hydroxyl groups; and (4) more transparent to electromagnetic waves 34 having a wavelength 36 longer than the visible region.

Without wishing to be bound by theory, it is believed that the presence of one or more hydroxyl groups in the conventional conducting liquid acts, at least in part, to render the conducting liquid immiscible with typical insulating liquids, but also absorbs electromagnetic waves having a wavelength greater than or equal to 1400 nm. By absorbing electromagnetic waves with a wavelength greater than or equal to 1400nm, these hydroxyl groups can prevent the conductive liquid from transmitting a sufficient percentage of incident electromagnetic waves to be sensed and processed and with a wavelength greater than or equal to 1400nm through the liquid lens. Thus, the one or more hydroxyl groups may prevent a liquid lens using a conventional conductive liquid from being used for applications intended to sense electromagnetic waves having a wavelength greater than or equal to 1400 nm. In some embodiments, the ionic compounds disclosed herein have few hydroxyl groups, which can help address the shortfalls of conventional conductive liquids for use in applications involving electromagnetic waves having wavelengths greater than or equal to 1400 nm.

An exemplary application that may involve sensing electromagnetic waves having a wavelength greater than or equal to 1400nm is optical communications, which may involve sensing electromagnetic waves having a typical wavelength of 1550 nm. Furthermore, some lidar measurement methods may involve sensing electromagnetic waves at a wavelength of 1550 nm. As another example, Short Wave Infrared (SWIR) imaging may involve sensing electromagnetic waves with wavelengths between 900nm and 1700nm (e.g., with InGaAs sensors).

In some embodiments, the conductive liquid and the insulating liquid have properties that help them be compatible for liquid lens applications. For example, the densities of the conducting liquid and the insulating liquid may be the same or substantially the same (e.g., differ by no more than about 3.10 degrees Celsius at 20 degrees Celsius)^-3g/cm³). In addition, the kinematic viscosities of the conductive liquid and the insulating liquid may be sufficiently low and/or the same or substantially the same (e.g., within 0cSt and ± 5cSt of each other within the temperature range of the intended application). In addition, the melting points of the conductive liquid and the insulating liquid may be sufficiently low (e.g., -20 degrees celsius or less, e.g., -40 degrees celsius). In some applications, the conductive liquid and the insulating liquid may be in liquid phase at a temperature in the range of-20 degrees celsius to 70 degrees celsius (e.g., at standard pressure, such as 1 atm). In other applications, the conductive liquid and the insulating liquid may be in liquid phase at a temperature in the range of-40 degrees celsius to 85 degrees celsius (e.g., at standard pressure, such as 1 atm).

Both dicyanamide anions and tricyanomethane anions can be matched with many possible cationic counterions to form ionic compounds for use as or in the conductive liquid 16. Exemplary cationic counterions that are paired with dicyanamide anions or tricyanomethane anions include imidazolium, pyrrolidinium, piperidinium, phosphonium, pyridinium, pyrrolinium, and sulfonium cations.

The imidazolium cation has the following general formula VI,

where R is hydrogen or alkyl and R' is hydrogen or any organic group, it should be noted that the number of hydroxyl groups in the organic group is preferably 0. In some embodiments of the imidazolium cation, R' is methyl and R is ethyl, the cation is referred to as a 1-ethyl-3-methylimidazolium cation. The density of the ionic compound dicyandiamide 1-ethyl-3-methylimidazolium at 26 ℃ is 1.101g/cm³Viscosity at 21 degrees celsius was 16.8mPa · s, melting point was-21 degrees celsius, and refractive index (589nm) was 1.516. The density of the ionic compound tricyanomethane 1-ethyl-3-methylimidazolium at 25 ℃ is 1.08g/cm³The viscosity at 25 degrees Celsius is 14.0cP, the melting point is-11 ℃, and the refractive index (589nm) is 1.512. The density of both dicyanamide 1-ethyl-3-methylimidazolium and tricyanomethane 1-ethyl-3-methylimidazolium are adapted to match the typical composition of the insulating liquid 18. Another imidazolium cation suitable for some embodiments is the 1-allyl-3-methylimidazolium cation. The density of the ionic compound dicyandiamide 1-allyl-3-methylimidazolium at 24 ℃ is 1.11g/cm³Viscosity at 18 degrees celsius was 16mPa · s, and melting point was below room temperature. Another imidazolium cation suitable for some embodiments is the 1-benzyl-3-methylimidazolium cation. The density of the ionic compound dicyandiamide 1-benzyl-3-methylimidazolium at 24 ℃ is 1.16g/cm³The viscosity at 25 degrees celsius was 78.5mPa · s, and the melting point was below room temperature. Another imidazolium cation suitable for some embodiments is the 1-butyl-3-methylimidazolium cation. The density of the ionic compound dicyandiamide, 1-butyl-3-methylimidazolium, at 25 ℃ is 1.06g/cm³Viscosity at 25 degrees celsius is 28mPa s, and melting point is below 0 degrees celsius. Ionic compound tricyanomethaneThe density of alkylated 1-butyl-3-methylimidazolium at 25 ℃ is 1.05g/cm³And a viscosity at 25 degrees celsius of 27.3 cP. Another imidazolium cation suitable for some embodiments is the 1-hexyl-3-methylimidazolium cation. The density of the ionic compound tricyanomethane 1-hexyl-3-methylimidazolium at 24 ℃ is 1.02g/cm³Viscosity at 25 degrees celsius was 39.2cP, and melting point was below room temperature.

The pyrrolidinium cation has the following general formula VII,

where R is hydrogen or alkyl and R' is hydrogen or any organic group, it should be noted that the number of hydroxyl groups in the organic group is preferably 0. In some embodiments of the pyrrolidinium cation, R is ethyl and R' is methyl, the cation is referred to as an N-ethyl-N-methylpyrrolidinium cation. In some embodiments, the ionic compound dicyanamide N-ethyl-N-methylpyrrolidinium may be an ionic compound suitable for use as or in the conductive liquid 16. In some embodiments, the ionic compound tricyanomethane N-ethyl-N-methylpyrrolidinium may be an ionic compound suitable for use as or in the conductive liquid 16.

Another pyrrolidinium cation suitable for some embodiments is the 1-butyl-1-methylpyrrolidinium cation. The density of the ionic compound dicyandiamide 1-butyl-1-methylpyrrolidinium at 20 ℃ is 1.02g/cm³Viscosity at 20 degrees celsius was 46mPa · s, and melting point was-55 degrees celsius. The density of the ionic compound tricyanomethane 1-butyl-1-methylpyrrolidinium at 25 ℃ is 1.01g/cm³The viscosity at 25 degrees Celsius is 26.9 cP. The density of both dicyanamide 1-ethyl-3-methylimidazolium and tricyanomethane 1-ethyl-3-methylimidazolium are adapted to match the typical composition of the insulating liquid 18. The melting point of dicyanamide 1-butyl-1-methylpyrrolidinium, well below-20 ℃, makes this ionic compound suitable for many applications of the conductive liquid 16 for the liquid lens 10.

The piperidinium cation has the following general formula VIII,

wherein R is hydrogen or an organic group, and R' is hydrogen or an organic group, wherein the number of hydroxyl groups in the organic group may be 0.

The phosphonium cation has the following general formula IX,

wherein R1, R2, R3, R4 are each independently hydrogen or any organic group wherein the number of hydroxyl groups in the organic group can be 0. Phosphonium cations suitable for some embodiments are trihexyltetradecylphosphonium cations. The density of the ionic compound dicyandiamide trihexyltetradecylphosphonium at 28 ℃ is 0.90g/cm³The viscosity at 25 degrees celsius was 361mPa · s, and the melting point was below room temperature. The ionic compound tricyanomethane trihexyltetradecylphosphonium is also commercially available.

The pyridinium cation has the following general formula X,

wherein R may be hydrogen or any organic group, wherein the number of hydroxyl groups in the organic group may be 0.

The pyrrolinium cation has the following general formula XI,

wherein R may be hydrogen or any organic group, wherein the number of hydroxyl groups in the organic group may be 0.

The sulfonium cation has the following general formula XII,

wherein R is¹、R²And R³May be hydrogen or any organic group, wherein the number of hydroxyl groups in the organic group may be 0.

The conductive liquid 16 may also include a solvent. However, the total weight/weight concentration of hydroxyl-containing species in the conductive liquid 16 should be less than 20%, less than 10%, less than 5%, or less than 1%. Exemplary polar solvents that do not include hydroxyl groups include dimethyl sulfoxide, dimethylformamide, dialkyl ethylene glycol ethers, dialkyl propylene glycol ethers, carbonates, and lactams.

Referring now to fig. 3, an electrowetting experiment was performed to determine the change in contact angle as a function of voltage for dicyanamide 1-ethyl-3-methylimidazolium (as conductive liquid 16) and diphenyldimethylgermane (as insulating liquid 18). The graph shows that the electrowetting hysteresis is low in the voltage range above 30 volts.

Referring now to fig. 4A and 4B, experiments were conducted to determine for (a) dicyanamide 1-ethyl-3-methylimidazolium; and (b) ethylene glycol, the percent transmittance of the incident electromagnetic wave 34 varying according to the wavelength 36 of the electromagnetic wave 34. Fig. 4A illustrates the results for ethylene glycol. FIG. 4B illustrates the results for dicyanamide 1-ethyl-3-methylimidazolium. In both experiments, the thickness of the liquid to which the incident electromagnetic wave 34 is directed is 1 mm. Experimental results have demonstrated that dicyanamide 1-ethyl-3-methylimidazolium generally has a higher transmission (percent transmission) than ethylene glycol for incident electromagnetic waves 34 with a wavelength 36 in the range 800nm to 2200nm, especially between 1400nm and 1600nm, especially at 1550 nm.

Examples

Several exemplary liquid lens formulations were prepared using a conductive liquid 16, the conductive liquid 16 comprising an ionic compound having a dicyanamide anion or a tricyanomethane anion. The examples disclose that the conductive liquid 16 comprising an ionic compound having dicyanamide anion or tricyanomethyl anion may have a chemical bond with an insulating compoundThe density of the rim liquid 18 is matched (by a difference of 0.10g/cm at a temperature of e.g. 20 degrees C)³Within). For example, the density is matched to a phase difference of 0.01g/cm³Within, 0.005g/cm³Up to, or at 0.001g/cm³Within. An exemplary formulation is then incorporated into the liquid lens 200, and the transmittance of the liquid lens 200 (including both the conductive liquid 16 and the insulating liquid 18) is determined as a function of the wavelength 36 of the incident electromagnetic wave 34. The transmittance of the formulation of the exemplary liquid lens 200 is compared to the transmittance of the commercially available liquid lens 200 in fig. 5.

Example 1

In the formulation of example 1, the conductive liquid 16 is 100% by weight dicyanamide 1-ethyl-3-methylimidazolium. The insulating liquid 18 includes dodecane, (25-35% nonafluorohexyl methylsiloxane) (65-75% dimethylsiloxane) copolymer, bis (nonafluorohexyl) tetramethyldisiloxane, and polydimethylsiloxane. Note that the densities of the conductive liquid 16 and the insulating liquid 18 are matched.

Example 2

In the formulation of example 2, the electrically conductive liquid 16 is 100% by weight tricyanomethane 1-butyl-1-methylpyrrolidinium. The insulating liquid 18 includes dodecane, (25-35% nonafluorohexyl methylsiloxane) (65-75% dimethylsiloxane) copolymer, bis (nonafluorohexyl) tetramethyldisiloxane, and polydimethylsiloxane. Note that the densities of the conducting liquid 16 and the insulating liquid 18 are matched to differ by 0.001g/cm³Within.

Example 3

In the formulation of example 3, the conductive liquid 16 includes tricyanomethane 1-ethyl-3-methylmidazolium and γ -butyrolactone. The insulating liquid 18 includes dodecane, (25-35% nonafluorohexyl methylsiloxane) (65-75% dimethylsiloxane) copolymer, bis (nonafluorohexyl) tetramethyldisiloxane, and polydimethylsiloxane. Note that the densities of the conductive liquid 16 and the insulating liquid 18 are matched to differ by 0.005g/cm³Within.

Referring now to fig. 5, the above formulation example 1 was tested to determine the variation in transmission of electromagnetic waves 34 through a liquid lens 200 depending on the wavelength 36 of the incident electromagnetic waves 34, the liquid lens 200 comprising a formulated conducting liquid 16 and an insulating liquid 18. The liquid lens 200 tested for transmittance did not include an anti-reflective coating. The use of an anti-reflective coating only increases the transmittance. The transmission of formulation example 1 was then compared to the transmission of the comparative formulation. The comparative formulation is available under the trademark "CRYPTOGRAMLenses are available from A-25HCommercially available liquid lenses of (1).The a-25H type zoom lens of (a) uses a conductive liquid containing water and ethylene glycol.

As revealed in the graph of fig. 5, the formulation example 1 is transparent to electromagnetic waves 34 having a wavelength 36 in the range of 900nm to 1150nm like the comparative formulation. Formulation example 1 is more transparent to electromagnetic waves 34 having a wavelength 36 greater than 1150nm (including at least the range of 1150nm to 1800 nm) than the comparative formulation. Formulation example 1 has a transmission of over 85% for electromagnetic waves 34 having a wavelength 36 of 900nm to about 1570 nm. Formulation example 1 is much more transparent to electromagnetic waves 34 with wavelengths 36 between 1400nm and 1600nm than the comparative formulation. For example, example formulations 1-3 transmit about 90% of incident electromagnetic waves 34 having a wavelength 36 of 1550nm, while comparative formulations transmit 57% of incident electromagnetic waves 34 having that wavelength 36. The 90% transmission of an incident electromagnetic wave 34 having a wavelength 36 of 1550nm is close to the theoretical limit of 92% without the anti-reflection coating. Furthermore, the thickness of the sample used for the transmittance experiment was thicker than in some applications of the conductive liquid. Therefore, the transmission levels for these applications will be higher than the results indicated here. Very similar characteristics are expected for formulation examples 2 and 3.

Example 4

In the formulation of example 4, the conductive liquid 16 includes dicyanamide 1-ethyl-3-methylimidazolium. The insulating liquid 18 includes 1-naphthyl triethylgermane, n-octyltris (trimethylsiloxy) silane, and polyphenyl ether santolinhtNote that the densities are matched to a phase difference of 0.008g/cm³Within.

Example 5

In the formulation of example 5, the conductive liquid 16 includes dicyanamide 1-ethyl-3-methylimidazolium. The insulating liquid 18 includes dodecane, (25-35% nonafluorohexylmethylsiloxane) (65-75% dimethylsiloxane) copolymer, bis (nonafluorohexyl) tetramethyldisiloxane, hexamethyldigermane and hexaethyldigermane.

Example 6

In the formulation of example 6, the conductive liquid 16 includes dicyanamide 1-ethyl-3-methylimidazolium. The insulating liquid 18 includes n-octyltris (trimethylsiloxy) silane, hexamethyldigermane and hexaethyldigermane.

The conductive liquid 16 and the insulating liquid 18 of example 6 are incorporated into the liquid lens 200. Fig. 6 illustrates an electrowetting curve illustrating the case where the optical power and the wavefront error vary according to the voltage applied to the liquid lens 10. In the range of-5D to +15D diopters, the calculated lens' hysteresis is greatest at 0.6D. The optical quality quantified by the root mean square wavefront error (RMS WFE) is 65nm maximum. These values are measured over a 2.5m clear aperture.

Those skilled in the art will note that in examples 1, 2, 3,5 and 6, the conductive liquid 16 has a higher optical refractive index than the insulating liquid 18. The corresponding liquid lens 10 will converge at low voltages and become divergent at higher voltages. In embodiment 4, the conductive liquid 16 has a lower optical refractive index than the insulating liquid 18. The corresponding liquid lens 10 will diverge at low voltages and become convergent at higher voltages. Either type of situation can be used to design an optical system with auto-focus, or tilt or higher aberration correction using a liquid lens, provided that the signs of variation of the drive parameters with voltage are taken into account in the design of the overall system.

In examples 1, 2, 4, 5 and 6 above, the ionic compound was 100% by weight of the conductive liquid 16. In example 3, the ionic compound is 80% by weight of the conductive liquid 16. In some embodiments, the ionic compound is at least 80 wt% conductive liquid 16, at least 85 wt% conductive liquid 16, at least 90 wt% conductive liquid 16, at least 95 wt% conductive liquid 16, at least 97 wt% conductive liquid 16, or about 100 wt% or 100 wt% conductive liquid 16. The manufacturing process used to manufacture the ionic compound may result in trace amounts of impurities, such as water, present in the liquid present as the ionic compound.

It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the claims.