The present invention relates to a lens, particularly a contact lens or an intraocular lens, having an adjustable focal length.
More particularly, the present invention relates to designs and methods of how to use and control such dynamic lenses. The present invention is not only applicable to contact lenses or intraocular lenses that are to be implanted into an eye but also to other lenses that may be used in a variety of different applications.
One particular aspect of the present invention shows how excellent optical quality can be achieved using liquid filled membrane lenses while employing actuation systems or a control system that consume little or no power, particularly no external power. Furthermore, an aspect of the present invention relates to a method for charging an energy source for the lens, particularly for a control system of the lens. Yet another aspect of the present invention relates to different methods for controlling the focal power or focal length of the lens. Further, a method to detect an input signal from the user is described. Particularly, some aspects of this invention aim at implementing a deformable contact or intraocular lens which allows correction of refractive and/or accommodation deficiencies of the eye of the user to deliver particularly high optical qualities. Furthermore, an aspect of the present invention relates to the control of focal power of the lens by means of a movement of the respective eyelid, wherein particularly a fast blinking motion of the eye lid can be decoupled from the focal power control movement of the eyelid, particularly be means of an (e.g. mechanical) low pass filter. Further, a method to control the time constants of the said low pass filter is described.
In WO2008115251 a soft contact lens is described that has a body with a central zone aligned with the optical axis of the eye when a user wears the lens. In one embodiment the soft lens includes a chamber that extends from a lower portion of the lens to its central axis and is arranged such that when a person looks down, a fluid is squeezed from the reservoir and changes the optical characteristics of the lens.
Further, WO98/14820 describes a variable focus contact lens, which has a body with a first half and an opposite second half. The body also has a first peripheral surface, an opposite second peripheral surface and an associated focal length. The lens includes a first material that is resilient so that when a compressive force is applied to the first surface and the second surface, the focal length of the lens changes in proportion to the compressive force. A force-distributing structure is disposed for distributing forces within the lens so as to inhibit astigmatism in the lens.
Furthermore, the fluid-filled adjustable contact lens of US 2012/0268712 shows an exemplary contact lens which includes a lens chamber configured to be positioned on a pupil of a user wearing the contact lens; a reservoir fluidly connected to the lens chamber, an actuator configured to transfer fluid back and forth between the lens chamber and the reservoir; a sensor configured to sense movement from the user and transmit a control signal when a predetermined movement is performed by the user, and a processor configured to actuate the actuator upon receipt of the control signal from the sensor.
Further, U.S. Pat. No. 8,755,124 describes an adjustable optical lens comprising a membrane, a support for the membrane, a fluid between the membrane and the support, an actuator for deforming the membrane, and a rigid ring connected to the membrane surrounded by the rigid ring where the rigid ring has a defined circumference.
Based on the above, the problem underlying the present invention is to provide an improved contact lens that particularly allows to precisely adjust the focal length of the contact lens and achieves a high optical quality.
This problem is solved by a contact lens having the features of claim 1. Preferred embodiments of the present invention are stated in the corresponding sub claims or are described below.
According to claim 1, the adjustable focus length lens is configured to be placed directly on the surface of an eye of a person (e.g. covering the pupil of said eye) or to be implanted into an eye of a person, and wherein the lens further comprises:
According to an embodiment, the lens is a contact lens. In this case, the base element may be configured to be placed directly on the surface of the eye of a person such that the back side of the base element contacts the eye. In an alternative embodiment it is also possible that the membrane is configured to contact the eye (with the front side of the membrane facing away from the back side of the membrane). Here, the incident light first passes through the base element then passes through the lens volume and finally through the membrane (i.e. through the curvature-adjustable area) before entering the eye on which it is placed.
Generally the transparent liquid can also be a transparent fluid. In some embodiments a fluid resides in the reservoir(s) and/or reservoir volume and/or lens volume and is used to adjust the curvature of the curvature-adjustable area. However, such a fluid can also be a liquid, particularly a transparent liquid.
Particularly, said ring member separates said lens volume adjacent or below the curvature-adjustable area of the membrane from the reservoir volume adjacent or below said boundary area of the membrane.
Further, particularly, the ring member may be integrally formed with the membrane and may protrude from said back side of the membrane.
Particularly, said curvature adjustable-area of the membrane is configured for passing light through the curvature adjustable-area which deflects the light passing through it according to the current curvature of said area of the membrane. Particularly, said curvature-adjustable area corresponds to the clear aperture of the lens according to the invention.
Further, particularly, the base element may form a base lens. Furthermore, particularly, the base element is stiffer than the membrane. Likewise, the ring member is preferably stiffer than the membrane so as to be able to define the shape of the lens (i.e. of said curvature adjustable area). Particularly, said ring member is a circular ring member.
Furthermore, according to an embodiment of the lens according to the invention, the back side of the base element comprises a concave curvature so that the back side of the base element can fully contact the eye of a person.
Particularly, the base element can consist of or comprise one of the following materials:
Particularly, the membrane can consist of or comprise one of the following materials:
Further, particularly, the liquid can be or comprise one of the following substances: a fluorinated silicone, water, an ionic liquid, ionic gels, a silicone, a contact lens cleaning solution, a salty water solution, an oil, a solvent.
According to an embodiment of the present invention, the lens volume is configured to be compressed, wherein when the lens volume is compressed, liquid residing in the lens volume is pressed into the reservoir volume such that the curvature of said curvature-adjustable area of the membrane decreases and the focal length of the lens increases.
According to an embodiment of the present invention, the reservoir volume is fluidly connected or fluidly connectable with the lens volume via at least one opening. Fluidly connected means that there exists a flow connection such that liquid can pass via said connection from the lens volume to the reservoir volume and vice versa.
Further, according to an embodiment of the present invention, the at least one opening is a circumferential gap defined by a face side of the ring member (which face side faces the front side of the base element) and the base element, wherein particularly, when the curvature-adjustable area of the membrane assumes a maximal convex curvature, said face side of the ring member contacts the front side of the base element.
Further, according to an embodiment of the present invention, the ring member is also connected to the front side of the transparent base element, particularly via its face side.
Particularly, the at least one opening is a channel extending (e.g. in or along a radial direction) through the ring member so that a flow connection, particularly a permanent flow connection, is established between the lens volume and the reservoir volume. According to a further embodiment, the ring member may also comprise a plurality of openings in the form of channels that fluidly connect the reservoir volume to the lens volume and that particularly extend in or along a radial direction through the ring member.
Further, said openings or channels may be delimited by the ring member and by the front side of the base element to which the ring member is attached, particularly via its face side facing the front side of the base element. Here, the openings can be formed by forming recesses into the edge or face side of the ring member to that channels result when the ring member is connected with its face side to the front side of the base element.
In the above embodiments, one or more dimensions of one opening or channel or said plurality of openings and channels, are (e.g. mechanically or electrically) controllable.
In other words, one opening or channel or said plurality of openings and channels can act as static and/or dynamic flow and/or pressure regulators (e.g. check-valves, regulating valves, or regulating flow resistors).
Further, particularly, one or more dimensions of one opening or channel or said plurality of openings and channels, are modulated prior, during, and/or after each or only selected eye blinks.
In other words, the fluid exchange between the reservoir volume and the lens volume is modulated synchronously with the eye blinking to enable, enhance, and/or suppress curvature changes of the lens (e.g. at least over a pre-defined time-period). For example, the flow and/or pressure resistance during an actuation movement is reduced, and/or the flow and/or pressure resistance between subsequent actuation movements is increased. In the above embodiments, the dimensions of the at least one opening or said plurality of openings are chosen particularly such that a time period over which the reservoir volume or the lens volume have to be compressed in order to yield a change of the curvature of the curvature-adjustable area is longer than the blink of an eye lasts, particularly longer than 1 second, particularly longer than 0.9 seconds, particularly longer than 0.8 seconds, particularly longer than 0.6 seconds, preferably longer than 0.5 seconds.
In other words, in case the openings or channels between the lens volume (e.g. optically clear aperture) and the reservoir volume are sufficiently small, an eye blinking movement of the person wearing the (e.g. contact) lens will be low-pass filtered and will thus not change the curvature of the lens. Only a slow enough actuation movement will result in a change of the focal power of the (e.g. contact) lens. Further, according to an embodiment of the present invention, the reservoir volume is configured to be compressed by an eyelid of an eye of the person when the (e.g contact) lens is arranged on the pupil of said eye, wherein particularly the reservoir volume is arranged such in the lens that the reservoir volume is compressed and the curvature of the central area of the membrane increases, when said person closes said eyelid partially [e.g. at least over a pre-defined time period).
The lens is particularly configured to maintain a compressed state of the reservoir. Such a state can be released e.g. by pushing on the lens volume.
Therefore, according to an embodiment of the present invention, the lens volume is configured to be deformed or compressed by the eyelid of the person when the contact lens is arranged on the pupil of the corresponding eye, particularly by closing said eyelid so as to press liquid from the lens volume back into the reservoir volume.
By selecting the geometries of the reservoir and lens volume appropriately, the overall change of the lens volume during the blinking of the eye is substantially zero. Here, substantially zero means that the focal power of the lens changes by not more than 0.25 diopter, and in particular not more than 0.1 diopter, and in particular not more than 0.05 diopter.
According to an embodiment, the reservoir volume is delimited by a first surface formed e.g. by the membrane and by a second surface formed e.g. by the base element, wherein said surfaces face each other, and wherein particularly said surfaces are configured to stick to each other (e.g. passively, e.g. due to adhesion forces, or actively, e.g. electrostatically) when making contact upon compression of the reservoir volume such that a compressed state of the reservoir volume can be maintained.
Further, the said stiction can be used to seal the opening and/or channels connecting the reservoir volume and lens volume.
Further, according to an embodiment of the present invention, the lens comprises at least one actuator that is configured to compress the reservoir volume so as to press liquid from the reservoir volume into the lens volume.
Further, particularly, according to an embodiment of the present invention, the curvature-adjustable area of the membrane is configured to act as a spring (and mechanical energy source) so that liquid can be pushed back from the lens volume into the reservoir volume, e.g. when at least one or said plurality of actuators and/or regulators stop acting, particularly compressing, the reservoir volume and/or stop acting on the openings or channels connecting the reservoir volume and the lens volume (e.g. when the reservoir volume is released).
Further, according to an embodiment the present invention, the lens is configured to regulate and/or completely hinder said pushing back of liquid from the lens volume into the reservoir volume by closing and/or sealing at least one or said multiple of openings or channels.
Further, according to an embodiment of the present invention, the reservoir volume is delimited by a first surface formed e.g. by the membrane and a second surface formed e.g. by the base element, wherein the two surfaces face each other.
Further, according to an embodiment of the present invention, the actuator comprises a particularly compliant (first) electrode (i.e. a flexible conducting element) attached to said first surface and an insulated (second) electrode (rigid or flexible conducting element) attached to said second surface such that an e.g. tapered gap is formed between the electrodes, wherein, when a voltage is applied to said electrodes said gap is reduced by an amount depending on the magnitude of the applied voltage and liquid is pressed from the reservoir volume (e.g. out of said gap) into the lens volume. Of course also the first electrode or both electrodes can be insulated. It is merely advantageous to insulate the electrodes with respect to each other.
Further, according to an embodiment of the present invention, the electrodes of the actuator are split up into individual sections forming pairs of electrodes that are configured to be actuated individually in a discrete or in a continuous manner. Discrete means that two electrodes forming a pair are either apart from each other forming a gap or contact each other (no gap). Thus a discrete amount of liquid can be transferred between said volumes by such a pair of electrodes depending on the size of the gap. Continuous means that the gap between two electrodes is closed continuously so that an adjustable amount of liquid can be transferred between said volumes. Particularly, an actuator that comprises the afore-described electrodes, pair of electrodes or corresponding segments or sections is also denoted as zipper or zipping actuator herein.
Further, according to an embodiment of the present invention, the lens is configured to use certain individual sections of said electrodes to (particularly passively) control fluid pressures and fluid flow rates for controlling the time periods upon which the fluid exchange between the reservoir volume and the lens volume takes place. In particular, the lens is configured to increase the flow and/or pressure resistance, and/or to completely suppress the fluid flow by closing and/or sealing at least one or multiple of said electrode sections.
Further, particularly, the center of the lens (i.e. curvature-adjustable area) is configured to act as a spring that wants to open (e.g. unzip) the actuator(s), i.e. move the first and second electrode(s) apart from each other corresponding to the open state of the actuator in contrast to a closed state where the respective first and second electrode contact each other and the associated gap vanishes in particular. Of course, the gap can also take any size between the said open and the said closed state. Further, the gap can be spatially varying, e.g. the first and second electrode can contact each other only at a certain percentage of the whole electrode area, whereas other areas remain in the open state. Such a partially closed/zipped state can be addressed by controlling the actuator force, in particularly, by controlling the actuator voltage.
According to an embodiment of the present invention, at least one or several non-linear elements (e.g. check-valves, friction elements, resonant cavities) are integrated into e.g. the fluid reservoir(s) or reservoir volume, channels, or actuator regions, to address various well defined actuator states (e.g. closed, partially closed by a certain percentage, or open). In contrast to above said actuator voltage control, non-linear elements can be used to address various actuator states without the need to control the actuator force. For example, the actuator state can be controlled by volume, e.g. by fully depleting a reservoir of fixed volume, or by pressure, e.g. by using a check-valve that opens at a specific pressure level)
Further, according to an embodiment of the present invention, the electrodes or the insulation layers can be modified (e.g. coated, micro-structured, chemically modified) such that they stick less, or do not stick, or do stick with a specific stiction force to each other when making contact. In other words, the threshold voltages for actuation can be reduced or stabilized by said surface modifications.
Further, according to an embodiment of the present invention, the said sticktion can be temporarily or permanently lowered or regulated by e.g. pressure waves (e.g. blinking caused pressure fluctuations, ultrasonic transducers), and/or alternating electrostatic forces (AC signals applied to the said or additional electrodes).
In other words, rapid eye-lid movements and/or AC voltage modulations (e.g. at the system resonant frequency) can assist the separation and/or approaching of the said actuator and/or regulator first and second electrodes, thus effectively lowering the voltage and/or energy required to access individual equilibrium states.
Further, according to an embodiment of the present invention, individual equilibrium states are connected such that energy (e.g. mechanical or electrical) from one state can be temporarily stored and transferred to another state (e.g. forming at least a bi-stable system or a system with multiple equilibrium states)
Further, according to an embodiment of the present invention, for reducing an influence of an eyelid on the reservoir volume and said electrodes, the reservoir volume is arranged next to the lens volume in a horizontal direction when the lens is arranged with respect to an eye as intended (in relation to an upright position of the head of the user).
Further, according to an embodiment of the present invention, the at least one actuator extends circumferentially around the ring member.
Further, according to an embodiment of the present invention, the ring member is at least 5 times, particularly at least 10 times, particularly at least 50 times, particularly at least 100 times, particularly at least 1000 times stiffer than the membrane.
Further, according to an embodiment of the present invention, the ring member has a circularity and flatness better than 25 μm, particularly better than 10 μm, particularly better than 5 μm at an interface between the ring 20 member and the membrane.
Further, according to an embodiment of the present invention, the lens comprises a sensor configured to sense a movement from the person wearing the lens, and to provide an output signal in response to a pre-determined movement of the user, wherein particularly said movement is a movement of an eyelid of an eye of said person, on which eye said contact lens is arranged
Further, the lens particularly comprises a processing unit that is configured to actuate the at least one actuator in response to the output signal provided by the sensor or in response to an output signal provided by an external device, wherein particularly the at least one actuator is actuated by applying said voltage or voltages to said electrodes of the at least one actuator as described above (e.g. for opening and closing gaps between associated first and second electrodes).
According to an aspect of the present invention a system may be provided comprising a lens according to the invention and an external device configured to provide said output signal.
Further, according to an embodiment of the present invention, said sensor is one of: a photosensitive element, a pressure sensing element, a capacitive sensing element, a thermal sensor, particularly a resistor. Particularly said resistor may extend along the periphery of the contact lens. When the person covers the resistor with an eyelid, the temperature of the resistor rises due to heat transferred from the eyelid to the resistor.
Further, according to an embodiment of the present invention, the contact lens comprises an electric energy source, particularly a battery.
Further, according to an embodiment of the present invention, said electric energy source is configured to be charged by means of one of:
Further, according to an embodiment of the present invention, said surfaces (e.g. of the membrane and base element, see above) are configured to stick to each other through a compressive force of the at least one actuator, meaning for instance that they are configured to stick to each other when brought to contact each other by means of the at least one actuator.
Further, according to an embodiment of the present invention, the back side of the base element is configured to be placed on the surface of the eye such that said back side contacts said surface of the eye, or that the front side of the membrane is configured to be placed on the surface of the eye such that said front side contacts said surface of the eye. Also in case of an intraocular lens, either the base element or the membrane may be configured to be passed first by incident light that hits the eye.
Further, according to an embodiment of the lens according to the invention, the reservoir volume is positioned in an upper half of the lens (or alternatively in a lower half for the lower eyelid), so that the reservoir volume is compressible by an onset of an upper (or lower) eyelid movement of an eye of the person when the lens is arranged on the pupil of said eye, so as to pump liquid from the reservoir volume into the lens volume for increasing the curvature of the curvature-adjustable area of the membrane.
Further, according to an embodiment of the lens according to the invention, the reservoir volume is formed by at least one, particularly two, or even more separate reservoirs which are each arranged in said upper (or lower) half and can each be brought in flow connection to the lens volume via a respective channel extending along a periphery of the lens volume from the upper half of the lens to the lower half of the lens.
Further, according to an embodiment of the lens according to the invention, said at least one or several channels are connectable to the lens volume via one or several valves which valve(s) is/are arranged in a lower (or upper) half of the lens so that the respective valve faces the reservoirs and/or so that the lens volume is arranged between the reservoirs and the valve(s).
Further, according to an alternative embodiment of the lens according to the invention, each reservoir comprises a valve via which the respective reservoir is connected to its associated channel, wherein the respective valve may comprises an osmotic membrane forming a wall (particularly bottom) of the respective reservoir, which osmotic membrane opens and allows the liquid to pass through it when a suitable voltage is applied to the osmotic membrane.
Alternatively, the respective valve may be one of the following valves: a valve comprising at least two electrodes for opening or closing the valve (e.g. a zipper or zipping actuator as described herein); a valve comprising a member out of a shape memory alloy or a phase change material for opening or closing the valve; a valve comprising an electromagnetic actuator for opening or closing the valve; a valve comprising a magnet that is configured to be moved by a another magnet for opening or closing the valve (e.g. an external magnet).
Further, according to an embodiment of the lens according to the invention, the lens comprises an energy source that is electrically connected to the valve via a power line for providing energy to the valve in order to open or close the valve.
Further, according to an embodiment of the lens according to the invention, the lens comprises a sensor for detecting an eyelid movement, which sensor is connected to the valve or the energy source via a data line, wherein the sensor is configured to provide an output signal when an eyelid movement is detected by the sensor and to provide the output signal to the valve or energy source via said data line for controlling the valve, particularly for closing or opening said valve.
Further, according to yet another embodiment of the lens according to the invention, the lens comprises a pump which comprises the reservoir volume, wherein the pump is configured to empty the reservoir volume by moving (e,g. pulling or pushing) a region of said membrane covering the reservoir volume into a dent of the base element forming at least a part of said reservoir volume.
Further, according to an embodiment of the lens according to the invention, said dent may comprise a concave shape (or a conical shape or some other suitable geometry)
Further, according to an embodiment of the lens according to the invention, the reservoir geometry is designed such that minimal or no energy is used to move (e.g. pull or push) said region of the membrane into the dent of the reservoir volume.
Further, according to an embodiment of the lens according to the invention, the pump is configured to generate an electrostatic force for pulling said region of the membrane into the dent of the reservoir volume, wherein for generating said force said region of the membrane comprises a flexible and particularly stretchable, electrically conducting electrode, and the base element comprises at least one corresponding counter electrode facing said electrode of the membrane.
Alternatively the valve may comprise a member out of a shape memory alloy that may be configured to expand upon heating (e.g. by means of an electrical current) and then moves said region of the membrane into the dent. Further, according to an embodiment of the lens according to the invention, dielectric layers may be applied either on both, the region of the membrane and the base element, or only on the base element.
Further, according to an embodiment of the lens according to the invention, a channel (e.g. in the form of a groove formed in the base element) via which the reservoir volume is connected to the lens volume leads to a particularly lowest (e.g. central) area of a bottom of said dent of the reservoir volume for draining said dent, wherein said groove is configured to be automatically sealed when said region of the membrane is moved (e.g. pulled or pushed) into the dent.
Further, according to an embodiment of the lens according to the invention, The amount of liquid transferred is properly defined by the reservoir volume. Several reservoir volumes can be combined to transfer fluid in discrete steps.
Further, according to an embodiment of the lens according to the invention, when said channel (or groove) is sealed, re-entry of liquid into the reservoir volume is blocked at an intersection of the channel/groove and the reservoir volume which intersection is also denoted as sealing line.
Further, according to an embodiment of the lens according to the invention, the pump is configured to keep the channel that forms a valve here in its sealed or closed state by pinning said region of the membrane to an (e.g. central) area on the bottom of said dent of the reservoir volume (this area is also denoted as sealing area and can be identical to said lowest area of the dent) using the electrode of the membrane on one side and on the other side said counter electrode and/or a central electrode that is arranged at the center of the bottom of the dent and surrounded by said counter electrode. Alternatively the member (shape memory alloy) may be used to pin down the membrane region.
Further, according to an embodiment of the lens according to the invention, the active electrode area and the electric power can be reduced after pinning the membrane to the bottom of the dent/reservoir volume. Further, the (e.g. circular) sealing area can be flexible, stiff, or even rigid.
Further, according to an embodiment of the lens according to the invention, particularly depending on the electric power applied, the sealed channel is configured to open at a certain back pressure, which initiates liquid back flow and refilling of the reservoir volume.
Further, according to yet another embodiment of the lens according to the invention, the lens comprises a channel for providing a flow connection between the reservoir volume and the lens volume, wherein the lens comprises a valve for opening or closing said channel, wherein said channel extends through a dent of the valve formed in the base element, which dent is covered by a region of said membrane, wherein the valve is configured to open or block said channel by moving (e.g. pulling or pushing) a region of said membrane covering the dent into the dent.
Further, according to an embodiment of the lens according to the invention, the dent geometry is designed such that minimal or no energy is used to move (e.g pull or push) the membrane into the dent.
Further, according to an embodiment of the lens according to the invention, the valve is configured to generate an electrostatic force for pulling said region of the membrane into the dent of the valve, wherein for generating said force said region of the membrane comprises a flexible and particularly stretchable, electrically conducting electrode, and the base element comprises at least one corresponding counter electrode. Alternatively, the valve may comprise a member out of a shape memory alloy for generating said force (see also above).
Further, according to an embodiment of the lens according to the invention, dielectric layers may be in turn applied either on both, the region of the membrane and the base element, or only on the base element.
Further, according to an embodiment of the lens according to the invention, said channel is configured to be automatically blocked when said region of the membrane is moved (e.g. pulled or pushed) into the dent of the valve.
Further, according to an embodiment of the lens according to the invention, when said channel is blocked, re-entry of liquid into the dent of the valve is blocked at intersections of the channel and the dent, which intersections are also denoted as sealing lines. Particularly, there are two such intersections or sealing lines, one where the channel enters the dent, and a further one where it leaves the dent.
Further, according to an embodiment of the lens according to the invention, the valve is configured to keep the channel in its blocked state by pinning said region of the membrane to an (e.g. central) area on the bottom of said dent of the valve (this area is also denoted as sealing area and can be identical to a lowest area of the dent) using the electrode of the membrane on one side and on the other side said counter electrode and/or a central electrode that is arranged at the center of the bottom of the dent and surrounded by said counter electrode and/or a first and/or a second sealing line electrode which extend along the sealing lines and are separated from the central electrode by a gap.
Further, according to an embodiment of the lens according to the invention, the active electrode area and the electric power can be reduced after pinning the membrane to the bottom of the dent/reservoir volume. Further, the (e.g. circular) sealing area can be flexible, stiff, or even rigid.
Further, according to an embodiment of the lens according to the invention, depending on the electric power applied, the valve is configured to open at a certain pressure, which allows passage of liquid between the reservoir volume and the lens volume via the channel.
In the embodiments described above where liquid is moved by means of an actuator (e.g. a pump), the membrane or at least a region thereof is configured to be pushed down by an eyelid of a user of the lens in order to assist in pumping liquid from the reservoir volume to the lens volume and/or from the lens volume into the reservoir volume, or in order to assist to close at least one or several valves of the lens.
Further, according to yet another embodiment of the lens according to the invention, the reservoir volume is covered by a bistable region of said membrane, wherein said region is movable with respect to the base element from a first stable state to a second stable state and vice versa, wherein in the first state, the reservoir volume is larger than in the second state, and wherein when said region is moved from the first state to the second state, liquid flows from the reservoir volume into the lens volume, and wherein when the region is moved from the second state to the first state, liquid flows from the lens volume back to the reservoir volume.
Further, according to an embodiment of the lens according to the invention, the lens comprises a channel connecting the reservoir volume to the lens volume to allow liquid to flow from the lens volume to the reservoir volume and vice versa.
Further, according to an embodiment of the lens according to the invention, the reservoir volume comprises a circular shape or a ring shape extending around the lens volume.
Further, according to an embodiment of the lens according to the invention, said bistable region of the membrane is configured to flip from one stable state to the other stable state when sufficient pressure is applied to a concave or convex surface of said region, wherein said region is configured to be actuated manually (e.g. by a person) in order to move it from one state to the other, particularly by means of a finger or an eyelid of a person.
Further, according to an embodiment of the lens according to the invention, said bistable region of the membrane is given a convex or concave shape using molding or thermoforming for providing said bi-stable state.
Further, according to an embodiment of the lens according to the invention, said region of the membrane is made out of an elastomer.
Further, according to an embodiment of the lens according to the invention, a portion of the membrane or said region of the membrane is made out of metal, or polymer, or an elastomer, or a heterogeneous structure of at least two materials. For example: a disk of Kapton embedded in silicone.
According to a further aspect of the present invention, a system is disclosed comprising a lens according to the invention as described or claimed herein and a container for storing the lens when the lens is not placed on the surface of an eye of the user, wherein said container comprises an electrically conducting coil for charging a battery of the lens by means of induction, when the lens is arranged in the container. Here, particularly, the lens may comprise an electrically conducting coil, too, that is connected to the energy source (e.g. battery) of the lens.
According to a further aspect of the present invention, a method for manufacturing a contact lens, particularly according to the invention, having the features of claim 58 is proposed, comprising the steps of:
Particularly, one of the following is applied to the membrane and/or the base element: a coating, at least one electrode, an insulation layer, an anti-stiction layer.
Particularly, the ring member can be plasma bonded to the membrane. Furthermore, the base element can be plasma bonded or glued to the membrane.
Further, particularly, the ring member can be integrally formed with the membrane (e.g. upon molding of the membrane), wherein the ring member can be stiffened by means of irradiating it with ultraviolet light or wherein the membrane can be softened by irradiating it with ultraviolet light. Materials that may be used for the ring member and membrane that can be stiffened by irradiating them with ultraviolet light are for example: silicones or urethanes. Further, materials that may be used for the membrane and ring member that can be softened by irradiating them with ultraviolet light are for example: silicones or urethanes).
Alternatively, a primer may be applied to the mold which is designed to chemically stiffen the ring member during molding of the membrane and integral ring member.
Further, according to an embodiment of the present invention, said filling is conducted using osmosis after said bonding has been performed.
For this, particularly, a pre-defined amount of water soluble salt is arranged on the base element or membrane before bonding so that said salt is arranged in the lens volume and/or lens reservoir after bonding, wherein then the bonded base element and membrane is soaked in the transparent liquid which enters the lens volume and reservoir volume by way of osmosis.
Further, according to an alternative embodiment of the present invention, said filling is conducted before said bonding, wherein said liquid is filled into a dent formed by the membrane, wherein thereafter said bonding is conducted, and wherein the lens volume and/or reservoir volume is freed from gas residing therein after said bonding.
Here, a glue, particularly a glue ring between the edge of the membrane and the edge of the base element, may be used, which glue is cured after freeing the lens volume/reservoir volume from said gas. This allows to adjust the initial focal length of the contact lens. Here, a glue that can be hardened by irradiating it with ultraviolet light may be used, wherein curing of the glue is then conducted by irradiating the glue with ultraviolet light after said degassing (i.e. freeing said volumes from the gas therein).
Furthermore, in an embodiment where filling is performed before bonding, the membrane may be provided (instead of molding) by vapor coating the liquid arranged on the base element by means of vapor depositing (coating) A material that can be used to vapor-deposit the membrane (the ring member is provided before (e.g. arranged on the base element) is e.g. parylene (i.e. chemically vapor deposited poly(p-xylylene) polymers).
The present invention can be used in a large variety of applications, such as contact lenses or intraocular lenses, or in any other lens that requires an adjustable focal length.
The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the drawings, wherein:
In the following the lens may always also be formed as an intraocular lens as shown in
As shown in
Furthermore, a transparent and elastically expandable membrane 20 is connected to said base element 10, wherein said membrane 20 comprises a back side 22 that faces said front side 11 of the base element 10.
For defining the shape of the deflected membrane 20, particularly of a curvature-adjustable (e.g. central) area 23 of the membrane 20, an e.g. circular ring member 30 is provided (also denoted as lens shaper) that is connected to the back side 22 of the membrane 20 and thus defines said (e.g. circular) area 23 of the membrane 20.
Particularly, the ring member 30 extends circumferentially about the optical axis (indicated by the dashed lines in
Below this area 23, the contact lens 1 a so-called lens volume 41 which is surrounded by the ring member 30. Further the contact lens 1 comprises a reservoir volume 42 below a boundary area 24 of said membrane 20. These two volumes 41, 42 of the contact lens 1 are filled with the same transparent liquid 50.
In order to be able to adjust the curvature of the curvature-adjustable area 23 of the membrane 22, which area 23 forms a convex bulge in
As can be inferred from
In order to actuate a change in curvature of the curvature-adjustable area 23, i.e. in the focal power of the contact lens 1, the reservoir volume 42 is configured to be compressed by an eyelid 4 of an eye 2 of the person when the contact lens 1 is arranged on the pupil 3 of said eye 2 as intended, wherein the reservoir volume 42 is arranged such in the contact lens 1 that the reservoir volume 42 is compressed and the curvature of the curvature-adjustable area 23 of the membrane 20 increases, when said person closes said eyelid 4 partially as shown in
A sequence A to E of such an actuation is shown in
Preferably, in this embodiment (as shown in
According to
Alternatively, as shown in
Further, as illustrated in
Further, as illustrated in
Further, as shown in
Here, narrowing the cross section of the at least one opening 60 or channel 43, said plurality of openings 60 or channels 43 described above, can be used to block low frequencies and/or DC components, e.g. the opening 60 or channel 43 could be used as a valve device. This intends to passively (cf.
High frequencies are also allowed to pass if the cross section is large enough. Then, eye blinking (see y3 in
Further,
As an alternative to a powerless actuation of the contact lens 1, the contact lens 1 may comprises at least one actuator 70 that is configured to compress the reservoir volume 42 so as to press liquid 50 from the reservoir volume 42 into the lens volume 41. Again, this actuation may be undone by the eyelid movement shown in
Such an actuator 70 may be actuated/controlled as indicated in
Particularly, the sensor 80 is one of: a photosensitive element, a pressure sensing element, a capacitive sensing element, a thermal sensor, particularly a resistor. For instance, a photosensitive element is arranged such in the contact lens that it can be covered by an eyelid and may thus generate a signal that can be used to control the processing unit 90. The resistor can be used to determine a position of the eyelid 4 since it is sensitive to heat that will be transferred from the eyelid 4 to the resistor. For instance, the resistor can extend along a periphery of the contact lens 1.
Further, the electric energy source 110 can be a battery that can be charged in a variety of different ways, already described above, for instance by means of inductive charging as indicated in
Further, a solar cell 120 may be used in order to charge the battery 110, which solar cell can be arranged, like the battery 110, besides the lens volume 41 outside the ring member 30 as shown in
Further, the sensor 80 can also sense the status of the contact lens by for example measuring a capacitance of the actuator 70. This can be done by superimposing a high frequency sensing signal to the actuator signal. The sensing signal allows to measure the capacitance of the actuator.
Further, additionally, as shown in
An embodiment of an actuator 70 that can be controlled and powered as described above is shown in
According thereto, the contact lens 1, which may be particularly designed as shown in
As further shown in
Further,
Further,
It is also within the spirit of this invention to have combinations of the discussed embodiments. For example the lens can be adjusted by mechanical pressure via eye lid and the electrostatic actuator is only required to maintain the adjusted curvature of the lens by attracting the boundary area 24 of said membrane 20 to the second surface 100 formed by the base element 10. Alternatively is is also possible to have an insulation layer on the electrode 71 but not on electrode 72. Furthermore it is possible to have the membrane 20 to be the surface in direct contact with the eye and the base element to face the outside world. Furthermore all contact lenses can be embedded in a hydrophilic encapsulation layer. Materials and manufacturing methods as suggested in the following hold for all embodiments described in the
The electrodes 71 (71a to 71d, 71e) and 72 preferably are deformable without being damaged. Advantageously, the first electrodes are therefore manufactured from one of the following materials:
The electrodes 71 and 72 may be deposited by means of any of the following techniques:
To control the stiction behavior of the membrane 20 and the base element 10 the following modifications (e.g. coatings) can be applied to the membrane 20, base element 10, electrodes 71, 72 or insulation layer 73:
The insulation layer 73 can, e.g., comprise or consist of:
The insulation layer 73 can, e.g., be deposited by means of any of the following techniques:
According to an embodiment, the above described actuator 70 using electrodes can be configured to form an active pump which is herein also denoted as active zipper pump which can be configured to be operated in the mode A shown in
In this mode A, a voltage step at E0 on the power line y1 initiates a period T1 in which the focal power of the lens increases from state S1 to S2. T1 is the zipping duration in which liquid is slowly transferred from the reservoir into the lens volume, e.g, by means of the zipper actuator 70 described above. The focal power change S2-S1 is either defined by zipping to a certain voltage dependent position, or by fully zipping one of many individual actuator segments (e.g. pairs of first and second electrodes 71, 71a, 71b, 71c, 71d, 71e, see above). The energy to transfer the transparent liquid 50 of the lens 1 is extracted from an energy source. In the event of an eye blink, no liquid 50 is permanently transferred, i.e. the focal power prior to the blink event is restored after the blink. The blinking induced focal power variations are small, because no significant liquid volume is transferred during a short blink. Liquid 50 is allowed to only flow slowly in all periods, i.e. the input signal y3 (and also y1) are low-pass filtered and cause slow change in focal power y2.
Alternatively, according to another embodiment, the lens 1 may be operated in the mode B shown in
Here, a voltage step at E0 alone does not initiate a focal power change. The focal power is incrementally increased at E2, E3, and E4; at which all of the following three causes are true: an eye blinking occurs, the power line y1 is powered, the control line y4 is on high (LH). The energy for the fluid transfer is extracted from the eye lid motion, or from another mechanical source (e.g. pressing with a fingertip or compressing the eye). After setting the control line on low (LL), the focal power is not permanently altered by any eye blink. The liquid transfer during the blinks E2, E3, and E4 is possible, because the liquid's resistance is lower during periods of low control signal. At event E5, significant liquid transfer is not possible due a higher liquid resistance. At E5 less liquid is transferred than at E2,E3, E4.
The control line y4 is not a must. In case of having a control line, the focal power can be freezed anytime at any value by setting the control line to low. In case of not having a control line, the liquid's resistance is permanently low. The focal power will temporarily change at any blinking event. As long as it takes to fully zip one of many individual actuator segments (see above), liquid transfer is permanent, i.e. no or little back flow occurs. After fully closing a segment (e.g. pair of electrodes, see above), blinking only causes a small temporary fluctuation in the focal power, but no permanent change.
Further, alternatively, the lens 1 may be operated in mode C corresponding to an active eye lid pump combined with a regulating valve or a frequency control. Here, the same figure applies as for the mode B, wherein now one has a slow decrease (constant negative slope) of y2 during all time periods.
In case of non-zero back flow, liquid back leakage is compensated i.e. refreshed by subsequent blinks. Continuous focal power states can be addressed depending on the average blinking interval, the liquid flow-in rate, and the liquid back-flow rate (dynamic rate equilibrium). In contrast to mode B, the focal power is set either by controlling the eye blink frequency (user initiated) or by changing the liquid flow resistance (regulating valve for in and/or out flow). A control line y4 is not a must, but can optionally be used to reduce the back-flow rate and/or increase the in-flow rate.
Further
Both principle embodiments shown in
Now, according to
As an alternative, according to
As can be seen from
The valve 43 is powered by an energy source 110 that is connected via a power line 110a to the valve 43 and may further be controlled by means of a sensor 80 that is connected to the valve 43 via a data line. For instance, the sensor 80 may detect an eyelid movement that transferred liquid 50 via the channels 43a, 43b into the lens volume through the opened valve 43 and may provide an output signal to close the valve 43 so as to maintain the transferred liquid 50 in the lens volume 41.
Particularly, the valve 43 can be an active or a passive valve system for controlling the in- and out pumping of liquid 50. The (valve) power source preferably requires 1000, or 100, or 10, or at least 2-times less energy than required to tune the lens 1 by means of the membrane 20, 23. The eye lid actuation can also be used to support a pumping system to reduce energy consumption.
Further, in case of passive check-valves, the valve can itself provide the sensor element. The valve energy would be drained from eye-lid pressurized reservoirs.
The valve 43 may be actuated (in case of an active valve 43) by means of
Furthermore, the valve 43 can be designed in a way that channels are squeezed by an actuator or clogged or reduced in cross section by any kind of movement of an obstacle to reduce or increase the flow.
Furthermore, in the embodiment shown in
For instance in case of a zipping valve 43, channels could be purely passively or actively controlled by means of a zipper device (cross section tuning or complete sealing after every pumping cycle).
Further, the zipping of the device could be assisted by fast blinking pulses (helps to overcome friction and adhesion issues)
In this way the respective osmotic membrane 430, 431 is laying under its associated reservoir 42a, 42b which can be pressurized by the eyelid. Furthermore, the osmotic membranes 430, 431 may be used as current generators by using the reverse electro-osmotic effect.
As before, the lens 1 may further comprise a sensor 80 for detecting an eyelid movement, which sensor 80 is connected to the energy source 110 via a data line 80a, which energy source 110 in turn is electrically connected to said osmotic membranes 430, 431 via corresponding power lines 80a, wherein the sensor 80 is preferably configured to provide an output signal when an eyelid movement is detected by the sensor 80 and to provide the output signal to the energy source 110 which then controls said voltage depending on the output signal.
According to
In the second state channel 43b is open and channel 43a closed, and due to the valve members 163a, 163b liquid 50 can flow out of the lens volume 41 into the reservoir volume 42.
In
In case liquid 50 shall be pumped out of the lens volume 41 in order to increase the focal length of the lens 1, the switch 161 is moved into its second state shown in
The switch 161 can be actuated using actuators but may also be manually actuated to change the state of the switch 161.
Further,
As shown in
Preferably, the pump 150 is configured to generate an electrostatic force for pulling said region 20a of the membrane 20 into the dent 42c, wherein for generating said force said region 20a of the membrane 20 forms a flexible and particularly stretchable, electrically conducting electrode 20b (see
As further shown in
When said groove/channel 42d is sealed by the pulled-in region 20a, re-entry of liquid 50 into the reservoir volume 42/dent 42c is blocked at an intersection 42g of the groove/channel 42d and the reservoir volume 42, which intersection 42g is also denoted as sealing line and indicated in
Further, the pump 150 is configured to keep the channel 42d in its sealed or closed state by pinning said region 20a of the membrane 20 to an area 42e on the bottom 42f of said dent 42c of the reservoir volume 42 (this area 42e is also denoted as sealing area) using the electrode 20b of the membrane 20 on one side and on the other side said counter electrode 10b and/or a central electrode 10c that is arranged at the center of the bottom 42f of the dent 42c and surrounded by said counter electrode 10b as shown in
The active electrode area and the electric power can be reduced after pinning the membrane 20 to the bottom 42f of the dent 42c /reservoir volume 42. Furthermore. Depending on the voltages applied to said electrode 10b, 20b, 10c, the sealed channel 42d is configured to open at a certain back pressure, which initiates liquid back flow and refilling of the reservoir volume 42.
Also here, the valve 160 is configured to generate an electrostatic force for pulling said region 20a of the membrane 20 into the dent 160c of the valve 160 for closing the valve 160/channel 160d, wherein for generating said force said region 20a of the membrane 20 forms a flexible and particularly stretchable, electrically conducting electrode 20b, and the base element 10 forms at least one corresponding counter electrode 10b.
Now, the channel 160d is configured to be automatically blocked when said region 20a of the membrane 20 is pulled into the dent 160c of the valve 160. When said channel 160d is blocked, re-entry of liquid 50 into the dent 160c and through the dent 160c of the valve 160 is blocked at intersections 160g of the channel 160d and the dent 160c which intersections are again denoted as sealing lines and are indicated in
Preferably, the valve 160 is configured to keep the channel 160d in its blocked state by pinning said region 20a of the membrane 20 to an area 160e on the bottom 160f of said dent 160c of the valve 160 (this area is also denoted as sealing area) using the electrode 20b of the membrane 20 on one side and said counter electrode 10b and/or a central electrode 10c that is arranged at the center of the bottom 160f of the dent 160c and surrounded by said counter electrode 10b (cf.
Again, the active electrode area and the electric power can be reduced after pinning the membrane 20 to the bottom 160f of the dent 160c /reservoir volume 42.
Also here, depending on the electric power applied, the valve 160 is configured to open at a certain pressure, which allows passage of liquid 50 between the reservoir volume 42 and the lens volume 41.
According to
After deflecting the region 20a of the membrane 20 to the maximum deflection state it touches the base element 10, the voltage applied can then be reduced to save static power during idle times (
After activating power on electrode 10c (
The electrodes 10b, 20b, 10c may consist of different materials and different thicknesses to optimize leakage current and operation voltage. On one hand, the small area electrode 10c could be covered with a thin (e.g. 0.1 to 10 micrometer) or ultra-thin (e.g. smaller than 100 nanometer), high-k, high-dielectric strength, e.g. non-flexible, inorganic dielectric material (e.g. Al2O3), to minimize static power consumption. On the other hand, the large area electrode 10b, and 20b could be covered with a thin (e.g. 0.5 to 5 micrometer) or ultra-thin (e.g. smaller than 0.5 micrometer), low-k, high-dielectric strength, flexible inorganic dielectric (e.g. Parylene or PDMS based)
Furthermore, the electrodes 10b, 20b could be fabricated with a radial gradient in the dielectric susceptibility and/or dielectric thickness, such that the local areal capacitance increases towards the center. In this way a larger maximum deflection can be achieved at a given voltage and leakage current.
Here, additional sealing line electrodes 10d, 10e may be used which are separated from the central electrode 10 by a gap 10f.
Again, in order to keep the valve 160 (or a pump 150) in its closed state, it is sufficient to pin the membrane 20 at a small area 160g and/or 160e (cf.
To seal the valve 160, it is sufficient to pin the membrane 20 at a small areas following the sealing lines 160g. Ideally, the electrodes 10b, 20b, 10c, 10d, 10e are isolated from each other by a lateral gap 10f.
Said electrodes 10b, 20b, 10c, 10d, 10e may consist of different materials and different thicknesses to optimize leakage current and operation voltage. On one hand, the small area electrodes 10c, 10d, 10e can be covered with an ultra-thin (<1 micrometer), high-k, high-dielectric strength, eventually non-flexible, inorganic dielectric material (e.g. Al2O3), to minimize static power consumption. On the other hand, the large area electrode 10b and 20b could be covered with a thin (1-2 micrometer, low-k, high-dielectric strength, flexible inorganic dielectric (e.g. Parylene or PDMS based).
The electrodes 10b, 20b may be fabricated with a radial gradient in the dielectric susceptibility and/or dielectric thickness, such that the local areal capacitance increases towards the center. In this way a larger maximum deflection can be achieved at a given voltage and leakage current.
Further, as shown in
Particularly, said member may comprise a circumferential (e.g. annular) frame 44a which is integrally connected to a central plate 44c via elongated curved arms 44b. In the expanded state, the arms 44b expand downwards so that the plate 44c moves said region 20a of the membrane 20 into the dent 42c, 160c and seals the reservoir/valve.
Furthermore, as shown in
Particularly, the reservoir volume 42 is covered by a bistable region 20a of the membrane 20 of the lens 1, wherein said region 20a is movable with respect to the base element 10 from a first stable state to a second stable state and vice versa, wherein in the first state the reservoir volume 42 is larger than in the second state, and wherein when said region 20a is moved from the first state to the second state, liquid 50 flows from the reservoir volume 42 into the lens volume 41, and wherein when the region 20a is moved from the second state to the first state, liquid flows from the lens volume 41 back to the reservoir volume 42.
The lens 1 further comprises a channel 43 that connects the reservoir volume 42 to the lens volume 41 to allow liquid 50 to flow from the lens volume 41 to the reservoir volume 42 and vice versa when the state of the region 20a changes accordingly.
As indicated in
Said portion 20a of the membrane 20 can be made of metal, or a polymer, or an elastomer, or a heterogeneous structure of at least two materials. For example: a disk of Kapton embedded in silicone.
The use of the lens according to the invention is very versatile and further includes without limitation devices such as: vision systems, ophthalmic lenses (contact lenses and intraocular lenses), ophthalmology equipment such as phoropter, refractometer, fundus cameras, ppt. biometrie, perimeter, refractometer, tonometer, anomaloskop, kontrastometer, endothelmicroscope, anomaloscope, binoptometer, OCT, rodatest, ophthalmoscope, RTA, slitlamp microscope, surgical microscope, auto-refractometer, keratograph, confocal imager, Scheimpflug camera, wavefront aberrometer, pupillometer, skin laser, eye laser, otoscope, laryngoscope, Raman spectrometer, portable spectrometer, photodynamic diagnosis; as well as lighting devices, lighting fixtures, devices for machine vision, laser processing devices, devices for conducting a light show, printers, metrology devices, (e.g. head-worn) glasses, medical devices, robot cams, motion tracking devices, microscopes, telescopes, endoscopes, binoculars, surveillance cameras, automotive devices, projectors, range finder, bar code readers, and web cams, fiber coupling, biometric devices, electronic magnifiers, motion tracking, intra-ocular lenses, mobile phones, military, digital still cameras, web cams, microscopes, telescopes, endoscopes, binoculars, research, industrial applications.
While there are shown and described presently preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.
Number | Date | Country | Kind |
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PCT/EP2015/059113 | Apr 2015 | EP | regional |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2016/059572 | 4/28/2016 | WO | 00 |