HK1183520A - Negative add liquid meniscus lens - Google Patents

Description

Liquid meniscus lens with increased negative power

Related patent application

This patent application claims priority to U.S. patent application serial No. 13/183,564 filed on 7/15/2011 and U.S. provisional patent application serial No. 61/376,044 filed on 8/23/2010.

Technical Field

The present invention relates generally to liquid meniscus lenses and, more particularly, to an arcuate liquid meniscus lens with a concave torus segment meniscus wall in which liquid meniscus boundary motion produces increased negative power.

Background

Liquid meniscus lenses are known in the industry. As discussed in more detail below in connection with fig. 1A and 1B, known liquid meniscus lenses are designed in a cylindrical shape with a peripheral surface formed by points at a fixed distance from a linear axis. The design of known liquid meniscus lenses is limited to having a first inner surface and a second inner surface that are substantially parallel and both perpendicular to the cylinder axis. Examples of known uses of liquid meniscus lenses include devices such as electronic cameras and cell phones.

Traditionally, ophthalmic devices (e.g., contact lenses and intraocular lenses) include biocompatible devices having corrective, cosmetic, or therapeutic properties. For example, contact lenses may provide one or more of the following effects: a vision correction function; cosmetic enhancement effect; and therapeutic effects. Each function is provided by a physical characteristic of the lens. Designs incorporating refractive properties into the lens may provide vision correction functions. Pigments incorporated into the lens can provide cosmetic enhancement. The active agent incorporated into the lens may provide a therapeutic function.

More recently, electronic components have been incorporated into contact lenses. Some of the components may include semiconductor devices. However, physical limitations including size, shape and control of the liquid meniscus lens preclude its application in ophthalmic lenses. Generally, the cylindrical shape of a liquid meniscus lens (sometimes referred to as the "puck" shape) does not conform to the shape of articles that may be used in the human eye.

Furthermore, the physical challenges involved with curved liquid meniscus lenses are not necessarily present in conventional liquid meniscus lens designs with parallel sidewalls.

Disclosure of Invention

Accordingly, the present invention provides a liquid meniscus lens including an arcuate front curve lens and an arcuate back curve lens. The present invention includes a meniscus wall having a physical structure that facilitates one or both of: the attraction and repulsion of the liquid contained within the lens and the formation of a meniscus with another liquid.

According to the invention, the first arcuate optic is immediately adjacent the second arcuate optic with a cavity formed therebetween. A saline solution and oil are maintained within the cavity. Applying an electrical charge to a meniscus wall located substantially in a peripheral region of one or both of the first arcuate optic and the second arcuate optic causes a change in the physical shape of a meniscus formed between a saline solution and an oil held within the cavity.

The invention includes a meniscus wall shaped substantially in the shape of a segment of a torus. The cross-section of the ring section in the present invention comprises a concave wall.

Drawings

Fig. 1A illustrates a prior art example of a cylindrical liquid meniscus lens in a first state.

Fig. 1B illustrates a prior art example of a cylindrical liquid meniscus lens in a second state.

Fig. 2 illustrates a tangential sectional profile of an exemplary liquid meniscus lens, according to some embodiments of the invention.

Fig. 3 illustrates a cross section of a portion of an exemplary arcuate liquid meniscus lens, according to some embodiments of the invention.

Fig. 4 illustrates additional exemplary aspects of an arcuate liquid meniscus lens.

Fig. 5 illustrates a meniscus wall element within an arcuate liquid meniscus lens according to some embodiments of the present invention.

Fig. 6A illustrates a concave meniscus wall within a liquid meniscus lens, showing the liquid meniscus boundary in an unpowered state.

Fig. 6B illustrates a concave meniscus wall within a liquid meniscus lens, showing the liquid meniscus boundary in a powered state.

Fig. 6C illustrates a concave meniscus wall within a liquid meniscus lens, showing the powered and unpowered states of the liquid meniscus boundary in a single diagram for comparison.

Fig. 7 illustrates a concave ring segment, which is the shape of a concave meniscus wall when viewed alone from the resting state of an arcuate liquid meniscus lens.

Detailed Description

The present invention provides a liquid meniscus lens with at least one of a front curve lens and a back curve lens defining a meniscus cavity of the liquid meniscus lens.

Term(s) for

In the description and claims directed to the invention, the terms used are defined as follows:

contact angle: the angle at which the oil/saline solution interface (also referred to as the liquid meniscus boundary) contacts the meniscus wall. In the case of a linear meniscus wall, the contact angle is the angle measured between the meniscus wall and a line tangent to the liquid meniscus boundary when the liquid meniscus boundary contacts the meniscus wall. In the case of a curved meniscus wall, the contact angle is the angle measured between a line tangent to the meniscus wall and the liquid meniscus boundary at which they meet.

Liquid meniscus boundary: an arcuate surface interface between the saline solution and the oil. Generally, the surface will form a lens that is concave on one side and convex on the other side.

A meniscus cavity: a space within the arcuate liquid meniscus lens between the front curve lens and the back curve lens, in which an oil and saline solution is retained.

Meniscus wall: a particular area on the interior of the front curve lens is such that it is within the meniscus cavity, while the liquid meniscus boundary moves along the meniscus cavity.

Optical zone: as used herein, refers to the area of an ophthalmic lens through which a wearer of the ophthalmic lens views.

Sharp edge: a geometric feature of an inner surface of either the front curve or the back curve lens sufficient to encompass the location of the two predetermined fluid contact lines on the optic. The sharp edges are typically external angles rather than internal angles. The fluid is used as a reference point, and the angle is larger than 180 degrees.

Referring now to fig. 1A, which is a cross-sectional view depicting a prior art lens 100, a cylinder 110 contains an oil 101 and a saline solution 102 therein. The cylinder 110 comprises two plates 106 of optical material. Each plate 106 includes a flat inner surface 113 and 114. The cylinder 110 includes a substantially rotationally symmetric inner surface. In some prior art embodiments, one or more surfaces may include a hydrophobic coating. Electrodes 105 are also included on or around the periphery of the cylinder. An electrical insulator may also be used in close proximity to the electrode 105.

According to the prior art, each of the inner surfaces 113 and 114 is substantially flat or planar. An interface surface 112A is defined between the brine solution 102A and the oil 101. As shown in fig. 1A, the shape of the interface 112A is combined with the refractive index properties of the saline solution 102A and the oil 101 to receive incident light 108 through a first inner surface 113 and provide divergent light 109 through a second inner surface 113. The shape of the interface surface between the oil 101 and the brine solution 102 is changed by applying a current to the electrode 105.

Fig. 100A shows a perspective view of the prior art lens shown at 100.

Referring now to FIG. 1B, a prior art lens 100 is shown in an energized state. The energized state is accomplished by applying a voltage 114 across the electrodes 115. The shape of the interface surface 112B between the oil 101 and the brine solution 102 is changed by applying a current to the electrode 115. As shown in fig. 1B, incident light 108B passing through the oil 101 and the brine solution 102B is focused into a converging light pattern 111.

Reference is now made to fig. 2, which is a cross-sectional view of a liquid meniscus lens 200 with a front curve lens 201 and a back curve lens 202. The front curve lens 201 and the back curve lens 202 are positioned next to each other and form a cavity 210 therebetween. The front curve lens includes a concave arcuate inner lens surface 203 and a convex arcuate outer lens surface 204. The concave arcuate lens surface 203 may have one or more coatings (not shown in fig. 2). The coating may comprise, for example, one or more of an electrically conductive or insulating material, a hydrophobic material, or a hydrophilic material. One or both of the concave arcuate lens surface 203 and the coating are in liquid and optical communication with oil 208 contained in a cavity 210.

The back curve lens 202 includes a convex arcuate inner lens surface 205 and a concave arcuate outer lens surface 206. The convex arcuate lens surface 205 may have one or more coatings (not shown in fig. 2). The coating may comprise, for example, one or more of an electrically conductive or insulating material, a hydrophobic material, or a hydrophilic material. At least one of the convex arcuate lens surface 205 and the coating is in liquid and optical communication with a saline solution 207 contained in a cavity 210. The saline solution 207 contains one or more salts or other conductive components and thus may be attracted or repelled by electrical charges.

In accordance with the present invention, a conductive coating 209 is positioned along at least a portion of the perimeter of one or both of the front curve lens 201 and the back curve lens 202. The conductive coating 209 may include, but is not limited to, gold or silver, and is preferably biocompatible. Applying an electrical charge to the conductive coating 209 causes the conductive salts or other components in the saline solution to be attracted or repelled.

The front curve lens 201 has an optical power associated with light passing through a concave arcuate inner lens surface 203 and a convex arcuate outer lens surface 204. The optical power may be 0, or may be positive or negative power. In some preferred embodiments, the optical power is that which is typically present in a corrective contact lens, such as, by way of non-limiting example, a power between-8.0 and +8.0 diopters.

The back curve lens 202 has an optical power associated with light passing through a convex arcuate inner lens surface 205 and a concave arcuate outer lens surface 206. The optical power may be 0, or may be positive or negative power. In some embodiments, the optical power is that power typically present in a corrective contact lens, such as a power between-8.0 and +8.0 diopters as a non-limiting example.

Various embodiments may also include a change in optical power associated with a change in shape of a liquid meniscus 211 formed between the saline solution 207 and the oil. In some embodiments, the change in optical power may be relatively small, for example, between 0-2.0 diopters. In other embodiments, the change in optical power associated with the change in shape of the liquid meniscus may be up to about 30 or more diopters. In general, a larger change in optical power associated with a change in shape of the liquid meniscus 211 is associated with a relatively thicker lens thickness 210.

According to some embodiments of the present invention, such as may be included in an ophthalmic lens, such as a contact lens, the transection lens thickness 210 of the arcuate liquid meniscus lens 200 will be up to about 1,000 microns thick. An exemplary lens thickness 210 of the relatively thin lens 200 may be up to about 200 microns thick. A preferred embodiment may include a liquid meniscus lens 200 having a lens thickness 210 of about 600 microns thick. Generally, the front curve lens 201 can have a cross-sectional thickness of between about 35 microns and about 200 microns, and the back curve lens 202 can also have a cross-sectional thickness of between about 35 microns and 200 microns.

According to the present invention, the cumulative optical power is the sum of the optical powers of the front curve lens 201, the back curve lens 202, and the liquid meniscus 211 formed between the oil 208 and the saline solution 207. In some embodiments, the optical power of the lens 200 will also include a refractive index difference between one or more of the front curve lens 201, the back curve lens 202, the oil 208, and the saline solution 207.

In those embodiments that include an arcuate liquid meniscus lens 200 incorporated into a contact lens, it is also desirable that the relative positions of the saline 207 and oil 208 within the curved liquid meniscus lens 200 remain stable as the contact lens wearer moves. Generally, it is preferred that the oil 208 is prevented from flowing and moving relative to the saline 207 when the wearer moves, and therefore the combination of oil 208 and saline solution 207 is preferably selected to have the same or similar density. Furthermore, the oil 208 and the brine solution 207 preferably have a relatively low immiscibility such that the brine solution 207 and the oil 208 will not mix.

In some preferred embodiments, the volume of saline solution contained within the cavity is greater than the volume of oil contained within the cavity. In addition, some preferred embodiments include a saline solution 207 in contact with substantially the entire inner surface 205 of the back curve lens 200. Some embodiments may include a volume of oil 208 that may be about 66% or more by volume compared to an amount of saline solution 207. Some additional embodiments may include an arcuate liquid meniscus lens in which the volume of oil 208 is about 90% or less by volume compared to the amount of saline solution 207.

Referring now to fig. 3, a cross-sectional view of an edge portion of an arcuate liquid meniscus lens 300 is shown. As described above, the arcuate liquid meniscus lens 300 includes combined front curve lens 301 and back curve lens 302 elements. The front curve lens 301 and the back curve lens 302 may be formed of one or more at least partially transparent materials. In some embodiments, one or both of the front curve lens 301 and the back curve lens 302 comprise a plastic that is generally optically transparent, such as one or more of the following: PMMA, Zeonor and TPX.

For example, one or both of the front curve lens 301 and the back curve lens 302 may be formed by one or more of the following methods: processing by a single-point diamond turning lathe; injection molding; and the digital micromirror device is freely shaped.

One or both of the front curve lens 301 and the back curve lens 302 may include a conductive coating 303, as shown, the conductive coating 303 extending along a peripheral portion from 309 to 310. In some preferred embodiments, the conductive coating 303 comprises gold. The gold may be applied by sputtering, vapor deposition or other known methods. Alternative conductive coatings 303 can include, by way of non-limiting example, aluminum, nickel, and indium tin oxide. Generally, the conductive coating 303 will be applied to the peripheral area of one or both of the front curve lens 301 and the back curve lens 302.

In some embodiments of the present invention, the back curve lens 302 has a conductive coating 304 applied to a particular area. For example, a portion around the perimeter of the back curve lens 302 may be coated from the first boundary 304-1 to the second boundary 304-2. For example, the gold coating may be applied by a sputtering method or vapor deposition. In some embodiments, a mask may be used to apply gold or other conductive material in a predetermined pattern around one or more peripheral portions of the front curve lens 301 or the back curve lens 302. Alternative conductive materials may be applied using a variety of methods and may cover different areas of the back curve lens 302.

In some embodiments, the conductive flow path, such as one or more holes or slits in the back curve lens 302, may be filled with a conductive filler material, such as a conductive epoxy. The conductive filler may provide electrical conduction to the conductive coating on the inner surface of one or both of the front curve lens 301 and the back curve lens 302.

In another aspect of the invention, one or both of the front curve lens 301 and the back curve lens 302 may be formed from a variety of different materials, wherein typically the optical area (not shown) in the central region of the front curve lens 301 and the back curve lens 302 may comprise an optically transparent material and the peripheral region may comprise an opaque region comprising an electrically conductive material. The opaque region may also include one or more of a control circuit and an energy source.

In another aspect, in some embodiments, an insulator coating 305 is applied to the front curve lens 301. By way of non-limiting example, the insulator coating 305 may be applied in a region extending from the first region 305-1 to the second region 305-2. The insulator may comprise, for example, Parylene C, Teflon AF, or other materials having a variety of electrical and mechanical properties, as well as electrical resistance.

In some specific embodiments, the insulator coating 305 creates a boundary region to maintain a spacing between the conductive coating 303 and the saline solution 306, the saline solution 306 being contained in the cavity between the front curve lens 301 and the back curve lens 302. Accordingly, some embodiments include an insulator coating 305 patterned and disposed in one or more regions of one or both of the front curve lens 301 and the back curve lens 302 to prevent the positively charged conductor 303 from coming into contact with the negatively charged saline solution 306, wherein contact of the conductor 303 with the saline solution 306 could cause a short circuit. An embodiment may include a positively charged saline solution 306 and a negatively charged conductor 303.

Other embodiments may allow a short circuit to occur between the conductor 303 and the saline solution 306 as a reset function of the circuitry associated with the operation of the lens 300. For example, a short circuit condition may interrupt the power to the lens and cause the saline solution 306 and oil 307 to return to a default position.

Some preferred embodiments include conductors 303 that extend from a region 309 inside the cavity 311 to a region 310 outside the cavity 311. Other embodiments may include a channel 312 through the front curve lens or the back curve lens that may be filled with a conductive material 313, such as a waterproof conductive epoxy. The conductive material 313 may form or be connected to an electrical terminal outside the cavity. An electrical charge may be applied to the terminal and conducted through the conductive material 313 in the via 312 to the coating.

The thickness of the insulator coating 305 may vary as a lens performance parameter. In accordance with the present invention, the charged components, including the saline solution 306 and the conductor 303, are generally maintained on either side of the insulator coating 305. The present invention provides an indirect relationship between the thickness of the insulator coating 305 and the electric field between the saline solution 306 and the conductor 303, wherein the farther the saline solution 306 is spaced from the conductor 303, the weaker its electric field will be.

In general, the present invention provides that the electric field strength can be significantly reduced as the thickness of the insulator coating 305 increases. The closer the electric field, the more energy will generally be available for moving the spherical liquid meniscus boundary 314. As the distance between the saline solution 306 and the conductor 303 increases, the farther apart the saline solution 306 is from the electric field of the conductor coating 303, and thus the more difficult it is to move the spherical meniscus boundary 314. Conversely, the thinner the insulator coating 305, the more sensitive the movement of the spherical liquid meniscus 308 is to defects in the insulator coating 305. Generally, even relatively small holes in the insulator coating 305 will short the lens 300.

In some embodiments, it is desirable to include a saline solution 306 having a density about the same as the density of the oil 307 also contained within the lens 300. For example, the density of the brine solution 306 may preferably be within 10% of the density of the oil 307, and more preferably, the density of the brine solution 306 will be within 5% of the density of the oil, most preferably within about 1%. In some embodiments, the density of the brine solution 306 may be adjusted by adjusting the concentration of salts or other components in the brine solution 306.

According to the present invention, the arcuate liquid meniscus lens 300 will provide more stable optical quality by limiting the movement of the oil 307 relative to the front curve lens 301 and the back curve lens 302. One way to stabilize the movement of the oil 307 relative to one or both of the arcuate front curve lens 301 and the back curve lens 302 is to maintain a relatively consistent density of the oil 307 and the saline solution 306. Furthermore, the relative depth or thickness of the layer of saline solution 306 is reduced as compared to conventional cylindrical lens designs, since the inner surfaces of both the front curve lens 301 and the back curve lens 302 are curved designs. Thus, the position of the oil within the lens 300 becomes more stable in order to avoid oil movement and possible damage to the meniscus between the oil 306 and the saline solution 307.

In some preferred embodiments, the saline solution 306 provides a lower refractive index than the oil 307, which provides a relatively higher refractive index. However, in some embodiments, a saline solution 306 having a higher refractive index than the oil 307 may be included, in which case the oil 307 provides a relatively lower refractive index.

The front curve lens 301 and the back curve lens 302 may be secured in place proximate to each other using an adhesive 308, thereby retaining the oil 307 and the saline solution 306 therebetween. The adhesive 308 acts as a seal so that the saline 306 or oil 307 does not leak from the curved liquid meniscus lens 300.

Referring now to fig. 4, a curved liquid meniscus lens 400 is shown with a liquid meniscus boundary 401 between a saline solution 406 and an oil 407. According to some preferred embodiments, the first angular break in the arcuate wall extending between 402 and 403 defines a meniscus wall 405 in the front curve lens 404. When an electrical charge is applied and removed along the one or more conductive coatings or conductive materials 408, the liquid meniscus boundary 401 will move up and down the meniscus wall 405.

In some preferred embodiments, the conductive coating 403 will extend from an area inside the cavity 409 holding the saline solution 406 and oil 407 to an area outside the cavity 409 containing the saline solution 406 and oil 407. In such embodiments, the conductive coating 403 may be a charge conduit applied to the conductive coating 403 at a point outside of the cavity 409 to the area of the conductive coating within the cavity and in contact with the saline solution 406.

Referring now to fig. 5, a cross-sectional view of an edge portion of an arcuate liquid meniscus lens 500 with a front curve lens 501 and a back curve lens 502 is shown. An arcuate liquid meniscus lens 500 may be used to contain a saline solution 503 and an oil 504. The geometry of the arcuate liquid meniscus lens 500 and the properties of the saline solution 503 and oil 504 facilitate the formation of a liquid meniscus boundary 505 between the saline solution 503 and oil 504.

In accordance with the present invention, the shape of the liquid meniscus boundary 505, and thus the contact angle between the liquid meniscus boundary 505 and the front curve lens 501, changes as an electrical charge is applied to the surface of at least a portion of one or both of the front curve lens 501 and the back curve lens 502.

In accordance with the present invention, a change in the current applied to the saline solution through the conductive coating or material changes the position of the liquid meniscus boundary 505 along the meniscus wall 506. This movement occurs between first sharp edge 506-1 and second sharp edge 506-2.

In a preferred embodiment, when a current of a first magnitude (e.g., voltage and current associated with an unpowered or resting state) is applied to the lens, the liquid meniscus boundary 505 will be at or near the first sharp 506-1.

Application of a second magnitude of current, sometimes referred to as a powered state, may cause the liquid meniscus boundary 505 to move along the meniscus wall 506 generally towards the second sharp 506-2, thereby causing a change in the shape of the liquid meniscus boundary.

In some embodiments, the meniscus wall 506 will be a smooth surface. A smooth meniscus wall 506 surface may minimize defects in the insulator coating. Furthermore, a smooth meniscus wall 506 is preferred because random irregularities in surface texture when the lens is powered on or off may cause unstable fluid motion and thus cause unstable or unpredictable meniscus motion. In some preferred embodiments, the smooth meniscus wall includes a peak to valley measurement in the range of about 1.25 nanometers to 5.00 nanometers along the meniscus wall 506.

In another aspect, in some embodiments it is desirable for the meniscus wall 506 to be hydrophobic, in which case a defined texture, such as a nano-textured surface, may be incorporated into the design of an arcuate liquid meniscus lens.

In another aspect, in some embodiments, the meniscus wall 506 may be angled with respect to the lens optical axis. The angle may range from 0 ° (or parallel to the optical axis) to 90 ° or close to 90 ° (or perpendicular to the optical axis). As shown, and in some preferred embodiments, the meniscus wall 506 angle is typically between about 30 ° and 50 ° such that an arcuate liquid meniscus lens functions according to the contact angle currently between the liquid meniscus boundary 505 and the insulator coated meniscus wall 506. The angle of the meniscus wall 506 may approach 0 or 90, due to the use of different materials or for different optical purposes, such as telescopic vision.

In accordance with the present invention, the angle of the meniscus wall 506 may be designed to accommodate the magnitude of motion along the meniscus wall 506 that occurs upon application of a specified voltage and current. In some embodiments, as the meniscus wall 506 angle increases, the ability to change the lens power generally decreases within given lens size and voltage parameters. Furthermore, if the meniscus wall 506 is at or near 0 ° with respect to the optical axis, the liquid meniscus boundary 505 will advance almost straight onto the front optic. The meniscus wall angle is one of a number of parameters that can be modified to provide various lens performance effects.

In some preferred embodiments, the length of the meniscus wall 506 is about 0.265 mm. However, in various designs, the angle of the meniscus wall 506, along with the size of the entire lens, will naturally affect the length of the meniscus wall 506.

It is believed that the arcuate liquid meniscus lens 500 will fail if the oil 504 contacts the back curve lens 502. Thus, in a preferred embodiment, meniscus wall 506 is designed such that there is a minimum gap of 50 microns at its closest point between first sharp 506-1 and back curve lens 502. In other embodiments, the minimum gap may be less than 50 microns, although the risk of lens failure increases as the gap decreases. In other embodiments, the gap may be increased to reduce the risk of lens failure, but the overall lens thickness will also increase, which may be undesirable.

In another aspect of some preferred embodiments of the present invention, the behavior of the liquid meniscus boundary 505 moving with the meniscus wall 506 may be inferred using young's equations. Although young's equation defines the force balance that a droplet induces on a dry surface and assumes a perfectly flat surface, the basic properties may still apply to the electrowetting lens environment created within the arcuate liquid meniscus lens 500.

For example, when the lens is in an unpowered state, a first magnitude of electrical energy may be applied to the lens, whereby a balance of interface energies between the oil 504 and the saline solution 503 (referred to herein as the liquid meniscus boundary 505), between the oil 504 and the meniscus wall 506, and between the saline solution 503 and the meniscus wall 506 will be achieved, resulting in a balanced contact angle between the liquid meniscus boundary 505 and the meniscus wall 506. When changing the magnitude of the voltage applied to the arcuate liquid meniscus lens 500, the balance of the interfacial energies will change, resulting in a corresponding change in the contact angle between the liquid meniscus boundary 505 and the meniscus wall 506.

The contact angle of the liquid meniscus boundary 505 with the insulator coated meniscus wall 506 is an important factor in the design and function of the arcuate liquid meniscus lens 500, not only due to its role in young's equation in the motion of the liquid meniscus boundary 505, but also because the contact angle, in combination with the structure of the other arcuate liquid meniscus lens 500, serves to limit meniscus motion.

Discontinuities across the meniscus wall 506, such as sharp edges 506-1, 506-2, act as boundaries for the movement of the liquid meniscus 505 because they require a significant change in voltage to effect a sufficient change in the contact angle of the liquid meniscus to move the liquid meniscus boundary 505 past one of the sharp edges. By way of non-limiting example, in some embodiments, the contact angle of the liquid meniscus boundary 505 with the meniscus wall 506 is in the range of 15 ° to 40 °, whereas the contact angle of the liquid meniscus boundary 505 with the step 507 below the second sharp 506-2 may be in the range of 90 ° to 130 °, and in some preferred embodiments is about 110 °.

A voltage applied to the lens may cause the liquid meniscus boundary 505 to move along the meniscus wall 506 towards the second sharp 506-2. The natural contact angle between the liquid meniscus boundary 505 and the insulator coated meniscus wall 506 will cause the liquid meniscus boundary 505 to stop at the second sharp 506-2 unless a significantly higher voltage is provided.

At one end of the meniscus wall 506, the first sharp 506-1 generally defines a limit beyond which the liquid meniscus boundary 505 generally moves. In some embodiments, first sharp 506-1 is configured as a sharp edge. In other preferred embodiments, first sharp 506-1 has a defined small radial surface that is less likely to be defective during manufacturing. Conductive, insulative, and other possible desired coatings may not be deposited uniformly and as intended on sharp edges, but the defined small radial surface radius edges may be more reliably coated.

In some embodiments, first sharp 506-1 is configured at an angle of about 90 ° and has a defined radius of about 10 microns. The sharp edge may also be manufactured to have an angle of less than 90 °. In some embodiments, sharp edges having an angle greater than 90 ° may be used to increase the robustness of the sharp edge, but the design takes up more lens space.

In various embodiments, sharp edges 506-1, 506-2 may define a radius in the range of 5 microns to 25 microns. Larger defined radii can be used to improve coating reliability, but at the expense of taking up more space in the tight tolerances of the lens design. In this regard, as in many other lens design areas, there is a trade-off between ease of manufacture, optimization of lens function, and minimization of size. Various variables may be used to fabricate a practical, reliable arcuate liquid meniscus lens 500.

Second sharp 506-2 comprises a designed structure that limits movement of oil when a voltage is applied to arcuate liquid meniscus lens 500. In some embodiments, second sharp 506-2 may also comprise a generally sharp edge, or in other embodiments, second sharp 506-2 may comprise a defined radius of between 5 and 25 microns, most preferably 10 microns. The 10 micron radius performs as well as a sharp edge and can be manufactured using a single point diamond turning or injection molding process.

A vertical or near vertical step 507 extending to the beginning of the optical zone 508 of the front curve lens 501 may be included on the side of the second sharp 506-2 opposite the meniscus wall 506. In some embodiments, the height of the step 507 is 120 microns, but may also be in the range of 50 to 200 microns.

In some embodiments, the step 507 may be at an angle of about 5 ° to the optical axis. In other embodiments, the step 507 may be at an angle of only 1 ° or 2 °, or may be at an angle greater than 5 °. A step 507 with a smaller angle to the optical axis will generally be a more effective meniscus motion limiter because it requires a greater change in the contact angle of the liquid meniscus boundary 505 to move the meniscus wall 506 off the step 507. The radius of the transition from the step 507 to the beginning 508 of the optical zone is 25 microns. A larger radius would unnecessarily take up more space in the lens design. If space is needed, a smaller radius is acceptable and may be implemented. In this and other lens fields, the decision to use a defined radius rather than a theoretical sharp edge is based in part on the possibility of a lens element being converted to an injection molding process. The bend between the step 507 and the start of the optical zone 508 will improve plastic flow during the injection molding process and give the lens optimal strength and stress handling characteristics.

Referring now to fig. 6A, in one of many possible embodiments, a concave meniscus wall 601 is shown. The concave meniscus wall 601 element of the arcuate liquid meniscus lens is a ring segment if viewed from the resting state of the arcuate liquid meniscus lens alone, as shown in the perspective view of fig. 7.

Referring now to fig. 7, in some embodiments, meniscus wall 701 includes a surface that is concave with respect to the optical axis and has a uniform length between first sharp 702-1 and second sharp 702-2. The preferred embodiment includes a concave surface surrounding the entire lens.

Fig. 6A shows one possible embodiment, where a meniscus wall 601 concave with respect to the optical axis is placed at an angle of about 45 ° to the optical axis in an arcuate liquid meniscus lens containing oil 602 and saline solution 603. The liquid meniscus boundary 604A contacts the meniscus wall 601 at 605A (typically located near the end of the meniscus wall 601 closest to the first sharp 608). The contact angle is represented by 606A.

Referring now to fig. 6B, a voltage applied to the meniscus wall 601 causes the liquid meniscus boundary to move 605B along the meniscus wall 601 and generally towards the first sharp 608, thereby generating a contact angle 606B.

Thus, a liquid meniscus lens with a concave meniscus wall placed at a given angle with respect to the optical axis (as shown in fig. 6C) will exhibit: for a given amount of applied voltage, less lens power change than a liquid meniscus lens with a linear meniscus wall placed at a similar angle relative to the optical axis. A liquid MENISCUS LENS with a linear MENISCUS WALL is more fully described in U.S. patent application 61/359,548 entitled "LENS with simple front LENS system for LENS unit WALL" and filed on 6/29/2010.

In accordance with the present invention, a voltage applied to a liquid meniscus lens with a meniscus wall causes the liquid meniscus boundary 604 to move toward the first sharp 608 rather than toward the front curved lens 607, thereby creating an increasing negative power.

A particular change in the applied voltage results in a change in the interfacial energy balance and is therefore expected to cause a corresponding change in the contact angle between the liquid meniscus boundary and the meniscus wall. On a linear meniscus wall, the change in contact angle results in relatively large motion of the liquid meniscus boundary along the meniscus wall, which is relatively small and perhaps even reversed on a concave meniscus wall (fig. 6C).

While the invention has been described with reference to a specific embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope.

Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope and spirit of the appended claims.

Claims (31)

1. An optical lens, comprising:

a front curve lens comprising a front curve lens outer surface and a front curve lens inner surface, wherein the front curve lens outer surface and the front curve lens inner surface each comprise an arcuate shape;

a back curve lens comprising a back curve lens inner surface and a back curve lens outer surface, wherein the back curve lens inner surface and the back curve lens outer surface each comprise an arcuate shape, the back curve lens positioned proximate to the front curve lens such that a cavity, an optical axis passing through the front curve lens and the back curve lens, and an optical quality passing through the optical axis are formed between the front curve lens inner surface and the back curve lens inner surface;

a volume of saline solution and oil contained within a cavity formed between the front curve lens inner surface and the back curve lens inner surface, the volume of saline solution and oil including a meniscus therebetween;

a meniscus wall comprising the general shape of a conical frustum formed in one or both of the front curve lens and back curve lens and abutting the meniscus formed between the saline solution and oil, and at least a portion of the conical frustum being concave relative to the optical axis;

a conductive coating on at least a portion of the meniscus wall, wherein application of an electrical current across the conductive coating causes movement of the meniscus resulting in increased negative power in optical quality across the optical axis.

2. The optical lens of claim 1 wherein the conductive coating on at least a portion of the meniscus wall comprises at least one of gold and silver.

3. The optical lens of claim 2 wherein the volume of oil is less than a volume of saline solution contained within the cavity.

4. The optical lens of claim 3 wherein the volume of oil comprises about 66% or more by volume compared to an amount of saline solution.

5. The optical lens of claim 3 wherein the volume of oil comprises about 90% or less by volume compared to an amount of saline solution.

6. The optical lens of claim 2 wherein the volume of oil comprises a density approximately equal to a density of the saline solution.

7. The optical lens of claim 2 wherein the volume of oil comprises a density within about 10% of a density of the saline solution.

8. The optical lens of claim 2 wherein the volume of oil comprises a density within about 5% of a density of the saline solution.

9. The optical lens of claim 2 wherein the conductive coating extends from a region inside the cavity to a region outside the cavity.

10. The optical lens of claim 9, wherein the area of conductive coating external to the cavity forms an electrical terminal for providing an electrical charge to the liquid meniscus lens.

11. The optical lens of claim 9 wherein the saline solution and the oil form a meniscus and applying an electrical charge to a region of the conductive coating outside the cavity causes a change in a contact position of the meniscus along the meniscus wall.

12. The optical lens of claim 10 wherein the electrical charge comprises a direct current.

13. The optical lens of claim 10 wherein the electrical charge comprises about 20.0 volts.

14. The optical lens of claim 10 wherein the electrical charge comprises about 18.0-22.0 volts.

15. The optical lens of claim 10 wherein the electrical charge comprises about 5.0 volts.

16. The optical lens of claim 10 wherein the electrical charge comprises about 3.5 volts to about 7.5 volts.

17. The optical lens of claim 3 wherein the front curve lens outer surface comprises an optical power other than about 0.

18. The optical lens of claim 3 wherein the front curve lens interior surface comprises an optical power other than about 0.

19. The optical lens of claim 3 wherein the back curve lens outer surface comprises an optical power other than about 0.

20. The optical lens of claim 3 wherein the back curve lens interior surface comprises an optical power other than about 0.

21. The optical lens of claim 3 further comprising a channel through one or both of the front curve lens and the back curve lens and a conductive material filling the channel.

22. The optical lens of claim 21 further comprising a terminal in electrical communication with the conductive material filling the channel.

23. The optical lens of claim 22 wherein applying an electrical charge to the terminal causes a change in the shape of the meniscus.

24. The optical lens of claim 3 further comprising an insulator coating along at least a portion of the front curve lens interior surface, wherein the insulator coating comprises an electrical insulator.

25. The optical lens of claim 24 wherein the insulator comprises parylene c^TMAnd Teflon AF^TMOne kind of (1).

26. The optical lens of claim 24 wherein the insulator comprises a boundary region to maintain a spacing between the conductive coating and a saline solution contained in a cavity between the front curve lens and the back curve lens.

27. The optical lens of claim 3 wherein an angle of a conical frustum having at least a portion of the conical frustum concave toward the optical axis comprises about 30 ° to 50 °.

28. The optical lens of claim 27 further comprising a meniscus sharp adjacent the meniscus wall, the sharp comprising an angled structure for containing the volume of saline solution and oil.

29. The optical lens of claim 27 wherein the sharp comprises a radial surface portion.

30. The optical lens of claim 28 wherein the radial surface portion comprises a radius in a range of 5 microns to 25 microns.

31. The optical lens of claim 1 wherein the meniscus wall is formed in one or both of the front curve lens and back curve lens and abuts a meniscus formed between the saline solution and oil.