Spectacles with sandwiched polymer structure

Abstract

To improve spectacles.SOLUTION: A spectacle lens comprises: a first transparent cover member and a second transparent cover member, where the first cover member comprises a proximal surface arranged to face the eye when in use and the second cover member comprises a distal surface arranged to face the surroundings when in use; one or more actuators arranged to generate forces or torques on the first or second cover member along a circumference of the first or second cover member so as to generate a controllable change of curvature of the first or second cover member; and a transparent, deformable, non-fluid body sandwiched between the first and second transparent cover members.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to spectacles, and in particular to spectacles with lenses having adjustable refractive power. [Background technology]

[0002] The ability of the eye to focus on objects at different distances can be limited for various reasons. Typically, this ability decreases as a function of age. In that case, it may be necessary to use various glasses with different refractive powers or glasses with different or variable refractive powers, such as bifocal or progressive glasses. Summary of the Invention [Problem to be solved by the invention]

[0003] Although these solutions are very beneficial, the need to switch to different glasses or to use glasses with different built-in refractive powers is not optimal when compared to a person's vision having undegraded focusing ability.

[0004] Accordingly, it is an object of the present invention to provide improved eyewear that addresses the above-mentioned problems and other limitations in currently available eyewear. [Means for solving the problem]

[0005] It is an object of the present invention to provide improved eyeglasses, in particular eyeglasses that provide different refractive powers in a more user-friendly manner than conventional eyeglasses, and it is also an object of the present invention to further improve the vision of individuals who suffer from reduced focusing ability or other vision limitations compared to currently available eyeglasses.

[0006] According to a first aspect of the present invention there is provided a spectacle lens comprising: - a first transparent cover member and a second transparent cover member, the first transparent cover member having a proximal surface arranged to face the eye in use and the second transparent cover member having a distal surface arranged to face the environment in use; - one or more actuators arranged to generate a force or torque on the first or second cover member so as to generate a controllable change in curvature of the first or second cover member; a transparent, deformable, non-fluid body sandwiched between the first transparent cover member and the second transparent cover member; One of the first and second transparent cover members, on which one or more of the actuators act, is supported on its distal or proximal surface, respectively, by a sliding contact (304) that allows displacement of the distal or proximal surface relative to one or more of the actuators (160).

[0007] Advantageously, the controllable actuator allows control of the refractive power of the lenses in a pair of spectacles, which means that the refractive power of the lenses can be changed without the user having to look at different parts of the lens to access different refractive powers, as in traditional multifocal or progressive lenses.

[0008] Advantageously, the transparent, deformable non-fluid body supports the bending of the first or second cover member, such that the resulting bending approaches a spherical shape. That is, the polymer used for the non-fluid body creates a non-uniform distribution of the force applied to the cover member when the actuator is actuated. In comparison, hydrostatic pressure in a liquid is the same everywhere in the liquid. The non-uniform force distribution can be advantageous in some circumstances to generate a spherical deformation profile.

[0009] Additionally, non-fluid bodies are less sensitive to gravity compared to liquids, and therefore the use of non-fluid bodies reduces optical errors due to gravity effects.

[0010] One or more actuators may be arranged to generate a force or torque on the first or second cover member along a path that encircles at least a portion of the non-fluid body, such as along a circumference of the first or second cover member, to generate a controllable change in curvature of the first or second cover member.

[0011] The sliding contacts provided to allow displacement of the distal or proximal face relative to one or more actuators are optional and may be omitted in other configurations.

[0012] According to one embodiment, the proximal and / or distal surface is curved inwards when viewed from the eye.

[0013] According to one embodiment, one of the first and second transparent cover members acted upon by the one or more actuators is bendable by the force or torque generated by the one or more actuators, and the other of the first and second transparent cover members is shaped to provide static optical correction.

[0014] According to one embodiment, one of the first and second transparent cover members acted upon by one or more actuators is supported on a distal or proximal surface, respectively, by a sliding contact that allows the actuator to displace along the surface of the distal or proximal surface.

[0015] According to one embodiment, the eyeglass lens is provided such that the non-fluid body is capable of unconstrained expansion within an annular volume located between the first and second transparent cover members and surrounding the non-fluid body.

[0016] According to one embodiment, a spectacle lens is provided such that external light traveling through the spectacle lens towards the eye is refracted through a sandwich structure consisting of first and second transparent cover members and a non-fluid body (optionally including an optical coating on the distal faces of the first and second transparent cover members). Advantageously, the simple design of this spectacle lens provides a low component solution.

[0017] According to one embodiment, at least one of the first and second transparent cover members has an initial curved shape such that when the one or more actuators apply zero or minimal force to the first cover member or the second cover member, the spectacle lens has a non-zero refractive power.

[0018] According to one embodiment, at least one of the first and second transparent cover members has a concave or convex shaped portion that abuts the non-fluid body.

[0019] According to one embodiment, the one or more actuators are controllable to generate at least two predefined optical powers of the spectacle lens.

[0020] According to one embodiment, the spectacle lens is optimized to produce minimal optical errors at at least two predetermined refractive powers.

[0021] According to one embodiment, the one or more actuators are controlled via a control or power signal, the control or power signal being determined as a function of the measured data.

[0022] According to one embodiment, the actuator or actuators are controlled via a control signal, which is determined as a function of an error between a desired refractive power of the spectacle lens and measurement data relating to the actual refractive power.

[0023] According to one embodiment, the actuator is a linear displacement motor capable of maintaining an achieved curvature of the first or second transparent cover member in an unpowered state.

[0024] According to one embodiment, the minimum diameter of a line extending from one edge of the spectacle lens to the opposite edge and intersecting the centre point of the spectacle lens is 15 mm.

[0025] According to one embodiment, the sliding contact comprises one or more elastic elements connecting the one or more actuators to the distal face and / or the proximal face.

[0026] A second aspect of the present invention is - a spectacle lens according to a first aspect a power and control circuit for powering and controlling one or more actuators; The present invention relates to glasses comprising:

[0027] In general, the various aspects and embodiments of the invention can be combined and combined in any manner possible within the scope of the invention. These and other aspects, features and / or advantages of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

[0028] Embodiments of the present invention will now be described, by way of example only, with reference to the drawings in which: [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 shows a pair of glasses. [Figure 2A] FIG. 1 shows a front view of one of the eyeglass lenses and a side view of the lens. [Figure 2B] FIG. 1 shows a front view of one of the eyeglass lenses and a side view of the lens. [Figure 3A] 11A-11C show the principle of controlling the curvature of one of the first cover member or the second cover member. [Figure 3B] 11A-11C show the principle of controlling the curvature of one of the first cover member or the second cover member. [Figure 3C] FIG. [Figure 3D] FIG. 13 shows an example in which both the proximal surface of the first transparent cover member and the distal surface of the second transparent cover member are curved inward (bulging inward or concave) when viewed from the eye. [Figure 3E] 13A and 13B are diagrams showing an example in which one of the first and second transparent cover members that is not provided to be bent by an actuator has a convex portion, for example, centered on the optical axis. [Figure 4A]FIG. 13 shows the optical power and optical error as a function of the power applied to the actuator. [Figure 4B] FIG. 13 shows the optical power and optical error as a function of the power applied to the actuator. [Figure 5A] 13A-13C show alternative configurations of the actuator. [Figure 5B] 13A-13C show alternative configurations of the actuator. [Figure 6A] 13A and 13B are diagrams mainly showing another configuration of the sliding contact. [Figure 6B] FIG. 2 is a diagram mainly showing the elastic element of the sliding contact. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] 1 shows a pair of glasses 100 comprising two spectacle lenses 101 mounted in a spectacle frame 102. The glasses 100 further comprise a power and control circuit 150, which may be integrated into the frame 102, for powering and controlling one or more actuators 160 arranged to generate forces acting on the lens or lenses 101 to produce a controllable change in the optical power of the lenses 101. Mainly, the power and control circuit 150 and the actuators 160 are shown.

[0031] FIG. 2A shows a front view of one of the eyeglass lenses 101, and FIG. 2B shows a side or cross-sectional view of the lens 101.

[0032] The lens has a first transparent cover member 211 and a second transparent cover member 212. The first transparent cover member 211 is defined as the cover member that, in use, is located next to the eye 290. The second cover member 212 is therefore defined as the cover member that, in use, is located closest to the surroundings or target space.

[0033] The outwardly facing surface of the first transparent cover member 211 is defined as a proximal surface 213 that, in use, faces the eye 290. The outwardly facing surface of the second transparent cover member 211 is defined as a distal surface 214 that, in use, faces the surroundings.

[0034] The lens 101 comprises a transparent, deformable, non-fluid body 205 sandwiched between a first transparent cover member 211 and a second transparent cover member 212. The non-fluid body 205 abuts the inwardly facing surfaces of the first and second cover members 211, 212.

[0035] One or more actuators 160 are provided along a circumference 261 of the first or second cover members 211,212 to generate a force or torque on the first or second cover members.

[0036] Actuator 160 may be, for example, a linear displacement actuator, such as a linear piezoelectric motor arranged to apply displacement at several points along circumference 261, here four points are depicted.

[0037] The circumference 261 may be located on the outside of the transparent, deformable, non-fluid body 205 such that the non-fluid body 205 is surrounded by the circumference, as shown. However, the circumference 261 may also be located within an extension of the non-fluid body 205. The actuator 160 may be arranged to act on an edge 219 of the first or second cover member 211, 212.

[0038] Circumference 261 is therefore understood as a path that encircles at least a portion of the non-fluid body, such as a portion that includes optical axis 291 or a central portion of the non-fluid body.

[0039] Other arrangements are possible in which the actuator acts on a frame or mount, which in turn transmits a force to the lens 101. In this case, the force or torque from a single actuator may be distributed to the cover members 211, 212. The frame or mount may convert the rotation of the rotary actuator into a linear displacement.

[0040] The actuator 160 is arranged to generate a displacement along a circumference 261 in a direction perpendicular or substantially perpendicular to one of the surfaces, e.g., the proximal or distal faces 213, 214. Substantially perpendicular in this context may mean, for example, a deviation of 10 to 15 degrees from the perpendicular.

[0041] There may be other configurations in which the actuator acts on the edge 219, for example an actuator comprising a tightening belt that at least partially encircles the edge 219. Thus, in such other configurations, the actuator may be arranged to generate a force acting on the face of the cover members 211, 212.

[0042] As will be explained in more detail below, action of the actuator changes the curvature of the first or second cover member depending on the force, torque or displacement provided by the actuator. Thus, by controlling the actuator, the bending and thus the optical power of the lens 101 can be controlled.

[0043] To enable bending of the first membrane 211 or the second membrane 212, one of the first membrane and the second membrane that is not in contact with the actuator 160 may be supported by a portion of the eyeglass frame 202, i.e., such that the first membrane or the second membrane is fixed to the frame 102.

[0044] 2B shows that the second membrane 212 is fixed to the frame 102, 202 and the first membrane 211 is connected to one or more actuators 160. In another embodiment, the first membrane 211 is fixed to the frame 102, 202 and the second membrane 212 is connected to one or more actuators 160.

[0045] An actuator may be provided acting on both the first and second membranes 211, 212 such that both membranes are bent under the action of the actuator 160, possibly such that both actuators are independently controllable, i.e. the displacement / force applied to one of the cover members is independent of the displacement / force applied to the other. An example of such a solution is shown in Fig. 5A, where the actuator is fixed to the frame 120, 202 of the glasses and the cover members 211, 212 are fixed to the actuator.

[0046] 5B shows another actuator 160 constituted by one or more elements 501 arranged along the circumference 261. The actuator 160 may for example be constituted by a ring-shaped actuator element 501, such as a ring-shaped piezo element attached to the proximal and / or distal faces 213, 214 of the first and / or second cover members 211, 212.

[0047] The actuator 160 in the form of a ring-shaped actuator, such as a ring-shaped piezo element 501, or an individual distribution of surface-mounted elements 501, is arranged at the center of the optical axis 291, such that the distribution of elements 501 inside or along the circumference 261 of the ring element 501 allows the transmission of light. By supplying a power signal to the element 501, the element contracts or expands in a radial direction (e.g. in a plane perpendicular to the optical axis 291), essentially rotationally symmetric with respect to the optical axis 291. The generated stretching force T is transmitted to the cover members 211, 212, which causes bending due to the torque generated by the force T. The lens 101 in FIG. 5B may be connected to the frame, for example via the element 501 as in FIG. 5A, if both cover members are equipped with the element 501, or via a cover member as in FIG. 3B, if the cover member does not have the element 501.

[0048] The components of Figures 5A and 5B are explained in more detail in Figures 3D-3E.

[0049] The lens 101 defines an optical axis 291. Light (at least for some paraaxial rays) can be viewed as the axis along which light propagates from object space towards the eye 290. The planar or curved surfaces of the first and second transparent membranes 211, 212, e.g., the planar or curved proximal / distal surfaces 213, 214, may define, at at least one surface point, a plane or tangent plane perpendicular to the optical axis 291, or at least a plane or tangent plane that makes an acute angle with the plane perpendicular to the optical axis 291. Thus, the planes of the first and second transparent films 211 , 212 generally extend along a direction perpendicular to the optical axis 291 .

[0050] The transparent deformable non-fluid lens body 205 is preferably made from an elastic material. Because the lens body is non-fluid, no fluid-tight enclosure is required to hold the lens body and there is no risk of leakage. In a preferred embodiment, the lens body is made from a soft polymer, which may include several different materials such as silicones, polymer gels, polymer networks of cross-linked or partially cross-linked polymers, and miscible oils or oil compounds. The elastic modulus of the non-fluid lens body may be greater than 300 Pa, which allows to avoid deformation due to gravity during normal operation. The refractive index of the non-fluid lens body may be greater than 1.3. The non-fluid body 205 may have a refractive index that is equal to, substantially equal to, or close to the refractive index of the transparent cover members 211, 212 to reduce reflections at the boundaries of the non-fluid body 205.

[0051] The transparent cover members 211, 212 may be made from a number of different materials such as acrylic, polyolefin, polyester, silicone, polyurethane, glass, and others. At least one of the first cover member 211 and the second cover member 212, which are provided to be deformed by the actuator, has a suitable stiffness and thickness to allow bending upon actuation of the actuator 160. In general, the material of the first and / or second cover members 211, 212 may be formed of a material having a Young's modulus in the range of 5 MPa to 100 GPa to provide the required stiffness. For example, borosilicate glass has a Young's modulus of 63 GPa, and fused silica glass has a Young's modulus of 72 GPa.

[0052] The bending of the first and / or second cover members 211, 212 is at least partially due to the reaction force from the non-fluid lens body 105 which varies radially, which affects the sag of the cover members 111, 112 and therefore the optical power, instead of simply compressing the lens body vertically without a change in sag. A full description of the effect of the lens body 105 on the curvature of the cover members is described in WO2019002524A1, which is incorporated herein by reference. The material of the non-fluid lens body 105 is substantially incompressible. This incompressibility is at least partially responsible for allowing the first and / or second cover members 211, 212 to bend in a shape that provides an optical lens effect.

[0053] Similar to a conventional eyeglass lens, the lens 101 may include a coating, such as an anti-reflective coating, applied to the proximal surface 213 and / or the distal surface 214 .

[0054] The transparent cover members 211, 212 are generally slab-shaped and may be curved, flat, or a combination thereof. The slab-shaped cover members have first and second surfaces, e.g., distal surface 214 and inner surface 216, and edges, with the curvature extending along at least one direction on at least one of the surfaces. Thus, the transparent cover members 211, 212 may be curved along only one direction, or may be curved along two directions. Alternatively, one or both of the first and second surfaces may be flat. For example, one or both of the cover members 211, 212 may constitute a plano-convex or plano-concave lens.

[0055] The thickness of the cover member arranged to be bent by the actuator may range from 0.1 mm to 2 mm, or from 0.1 mm up to 10 mm, although other thicknesses are possible.

[0056] The spectacle lens 101 may have a minimum diameter of 15 mm defined by a line extending from one edge to the opposite edge and intersecting the center point of the spectacle lens, i.e. the minimum diameter of the lens 101 is generally greater than 15 mm. Typical diameters of the lens 101 range from 20 mm to 50 mm.

[0057] Figures 3A and 3B show the principle of controlling the curvature of one of the first or second cover members 211, 212. In Figure 3A, the first cover member 211 has a curved surface, which means that the lens can generate a non-zero refractive power.

[0058] The deformations and expansions shown in Figures 3A to 3C are greatly exaggerated. Also, the first cover member 211 is shown with an outwardly curved bend (as viewed from the eye side), although an inwardly curved shape would be more typical. However, both outwardly and inwardly curved bend shapes are viable for different vision corrections.

[0059] The curvature of the first cover member 211 in Fig. 3A may be due to a force applied by the actuator 160. Alternatively, the curvature of the first cover member 211 may be a preformed curvature. Thus, the first cover member 211 may have an initial curvature, i.e. a curvature that exists in the absence of actuator forces, meaning that the spectacle lens 101 has a non-zero refractive power when the actuator or actuators apply zero or minimal force to the first cover member 211 or the second cover member 212, e.g. in an unpowered state of the actuators.

[0060] 3B shows further bending of the first cover member 211 due to a displacement, for example in the direction of the optical axis, of the actuator 160. The further bending causes the optical power of the lens 101 to change.

[0061] Further bending of the first cover member 211 reduces the volume between the first membrane 211 and the second membrane 212, which means that the incompressible non-fluid body 205 expands radially away from the optical axis as shown in FIG. 3B, with the boundary of the non-fluid body 205 expanding from the boundary shown by the dotted line to the boundary 303 shown by the solid line.

[0062] The non-fluidic body 205 must be expandable unconstrained, substantially unconstrained, or at least with low resistance, so as not to cause deviations of the bent shape from the desired bent shape. Such deviations may result in optical errors such as wavefront aberrations. Thus, the spectacle lens 101 may have an annular volume 301 located between the first transparent cover member 211 and the second transparent cover member 212, surrounding the non-fluidic body 205, in which the non-fluidic body 205 may expand unconstrained. The annular volume 301 may be an air-filled volume, which may be directly connected to the surroundings so that air can flow freely or substantially freely between the annular volume 301 and the surroundings.

[0063] Figure 3A shows point A on the first cover member 211. Figure 3B shows that point A has moved to the right relative to the left actuator 160 as the bending of the first cover member 211 increases. Thus, as the bending of the first or second cover members 211, 212 changes, location A on the proximal or distal surface 213, 214 moves radially relative to the optical axis 291, e.g., in the cross-sectional view shown, in a direction 302 perpendicular to the optical axis 291.

[0064] In order to avoid stress in the first or second cover members, as shown primarily in Fig. 3C, the spectacle lens 101 has a sliding contact 304. One of the first and second transparent cover members arranged to be bent by one or more actuators is supported or mechanically engaged on the distal / proximal faces 213, 214 by the actuator 160 or by a portion of the actuator 160 that engages the cover members via the sliding contact 304.

[0065] The sliding contact 304 may be constituted by a low friction contact between the actuator 160 and the distal / proximal faces 213, 214. The low friction contraction may be achieved by a low friction material pair, i.e. the material of the contacting portion of the actuator 160 should provide low or sufficiently low friction with the transparent material of the cover members 211, 212. Examples include polyethylene and other plastic materials.

[0066] The sliding contact 304 ensures that a given point on the proximal / distal faces 213 , 214 can be displaced along that surface relative to a contact portion of the actuator 160 .

[0067] The sliding contact 304 is configured to allow the distal face 214 or the proximal face 213 to be displaced along a surface relative to the portion of the actuator 160 that is engaged with the surface. Furthermore, the sliding contact should provide a rigid (i.e. stiff) connection in a direction perpendicular to the surface or in the direction of displacement of the actuator 160 in the supported position, such that the displacement of the actuator is directly transmitted to the cover members 211, 212.

[0068] FIG. 6A shows another configuration of the sliding contact 304, which is constituted by an elastic element 601 disposed between the actuator 160 and the distal / proximal faces 213, 214, which elastic element 601 connects the actuator 160 to the distal / proximal faces 213, 214.

[0069] The elastic element 601 is configured to elastically deform in response to relative displacement between the actuator 160 and the distal / proximal faces 213, 214, for example in response to radial displacement therebetween (in one example radial movement in a direction 302 perpendicular to the optical axis 291).

[0070] The stationary xyz coordinate system is defined relative to the initial position of the elastic element 601, for example when the elastic element 601 is in a non-deformed state. In this example, the z-axis is parallel to the optical axis 291.

[0071] In the left image, the first transparent cover member 211 (which is also the second transparent cover member 212) has an initial curvature (bending), which may be preformed or due to an initial displacement. The contact point 681 of the first transparent cover member 211 at the interface between the elastic element 601 and the first transparent cover member 211 has x0,z0 in xz coordinates.

[0072] In the right diagram, actuator 160 is controlled to move or extend its piston or other displacement element a distance ΔL1 along the z-axis. This displacement causes a bending or additional bending in first transparent cover member 211, which results in contact point 681 moving from x0, z0 to x1, z1 due to the radial displacement of contact point 681 towards the optical axis and the displacement along the z-axis.

[0073] Bending of first transparent member 211 causes the interface surface between resilient element 601 and first transparent cover member 211 to rotate about the y-axis, ie, about an axis tangent to path 261 that generally circumscribes optical axis 291 .

[0074] In response to relative radial displacement between the first transparent cover member 211 and the actuator 160, the elastic element 601 is configured to elastically deform in the radial direction (here shown along the x-axis), as shown.

[0075] Additionally, the elastic element 130 is configured to elastically deform in response to a torque Ty acting about the y-axis or a tangential axis, the torque Ty being generated by bending of the first transparent cover member 211, including rotation about the y-axis, or generally by relative displacement between the first transparent cover member and the actuator displacement element.

[0076] Preferably, the elastic element 130 has a low stiffness in response to radial deformation and in response to rotation, such as rotation about a tangential axis (y-axis in this illustration) tangent to the path 261. A low stiffness is preferred so that the first transparent cover member 211 can bend without being subjected to surface stresses that may inappropriately affect the curvature of the first transparent cover member 211, which may lead to increased wavefront errors or other bending deviations due to the altered curvature. Undesirable stresses are for example due to forces and torques from the elastic element 601 acting in the radial and tangential directions.

[0077] On the other hand, the elastic element preferably has a high stiffness in the displacement direction of the actuator 150 , ie along the z-axis or along the optical axis 291 , in order to transmit the displacement of the actuator to the cover members 211 , 212 .

[0078] The elastic element 601 can be defined as a structure having a first portion 611 (e.g., a surface of the elastic element contacting the cover member 211, 212) fixed to the first or second transparent cover member 211, 212, and a second portion 612 (e.g., a surface contacting the actuator 160) fixed to the actuator 160 or a displacement element thereof. The first and second portions 611, 612 are elastically connected such that they can be elastically displaced relative to each other, for example, in a radial direction toward the optical axis 291. The elastic element 601 may be manufactured as a single piece of elastic material, such as silicone, polymers, metals, plastics, and other materials. In one example, the elastic element 601 is formed from an adhesive applied to connect the actuator 160 to the transparent cover member.

[0079] Thus, the elastic element 601 constituting the sliding contact 304 allows displacement of the first or second transparent cover member 211, 212 relative to the portion of the actuator 160 that engages the cover member (such as contact 681) in response to bending of the cover member.

[0080] According to another example, the elastic element 601 is configured as a spring element disposed between the actuator 160 and the distal / proximal faces 213, 214. For example, the spring element may be configured as a bending element having a relatively low radial stiffness, a relatively low rotational stiffness about a tangential axis, while having a relatively high stiffness along the optical axis.

[0081] 6B mainly shows the elastic element 601 including the spring element 651. The left diagram shows the elastic element 601 (part of the elastic element) including the spring element 651 in a state in which the actuator 160 is not generating force, i.e., F=0. Therefore, the first transparent cover member 211 is in a state in which the curvature is not changed by the actuator.

[0082] In the right-hand illustration, the actuator displacement element is actuated to cause a z-axis displacement of ΔL1. The z-axis displacement generates a non-zero counterbalancing force F1 in the z-direction (i.e., at the rest bending state of the cover member) due to a reaction force caused at least in part by bending of the first transparent cover member 211. The z-axis displacement generated by the actuator 160 bends the first transparent cover member 211 as shown in an exaggerated manner. The bending causes a radial displacement of the first portion 611 along the x-axis (here to the right) and a rotation of the first portion 611 about the y-axis, in addition to the z-axis displacement of ΔL1.

[0083] It will be appreciated that the sliding element contact 304 may comprise both a spring element 651 and an elastic material, such as, for example, an elastic adhesive disposed between the first and / or second portions 611, 612 and the surface of the first or second transparent cover members 211, 212.

[0084] Thus, generally speaking, examples of sliding element contacts 304 configured with elastic elements 601 and / or low friction contacts provide the same sliding response to displacements generated by the actuator 160 (particularly radial displacement A of contact point 681 (Figures 6A and 3C, respectively)) and also to rotations directing bending of the first or second cover members 211, 212 and to the transmission of actuator displacements to the first or second cover members.

[0085] In a possible configuration of the first or second cover member 211, 212, the first or second cover member has a reinforcing element, such as a reinforcing ring (not shown). The reinforcing element may be annularly shaped along the circumference 261 and may be, for example, glued to the distal / proximal faces 213, 214 of the cover members 211, 212. The reinforcing element may be made of metal or other rigid material. In this configuration, the contact part of the actuator 160, i.e. the part arranged to contact the cover members 211, 212, contacts the reinforcing ring, for example via the sliding contact 304. Obviously, the radial extension of the reinforcing element must be large enough to accommodate the radial displacement of the surface of the cover members 211, 212 due to bending.

[0086] FIG. 3D shows an example in which both the proximal surface 213 of the first transparent cover member 211 and the distal surface 214 of the second transparent cover member 212 are inwardly curved (inwardly bulging or concave) as viewed from the eye. An inwardly curved shape may be preferred for optometric reasons or to provide an attractive design of the eyeglasses. Also, only one of the proximal surface 213 of the first transparent cover member 211 and the distal surface 214 of the second transparent cover member 212 may be concave as viewed from the eye 290. The inwardly curved shape of one of the cover members 211, 212 configured to be bent by the actuator 160 may be due to pre-molding of the cover members. Thus, the curvature of the inwardly curved shape may be changed by the actuator 160 to provide a variable optical power.

[0087] FIG. 3D also shows that the proximal surface 213 and inner surface 315 of the first cover member 211 have different curvatures, as do the distal surface 214 and inner surface 316 of the second cover member 211. The different curvatures of a given cover member 211, 212 provide optical power or optical correction as used in conventional eyeglass lenses. Also, only one of the first cover member and the second cover member may have a different curvature. For example, the first and second transparent cover members 211, 212 that are not provided to be bent by an actuator may be shaped to provide static optical correction. The static optical correction may include correction for myopia, hyperopia, astigmatism, etc.

[0088] 3E shows an example in which one of the first and second transparent cover members 211, 212, which is not provided to be bent by an actuator, has a convex portion 330, for example centered on the optical axis, which forms part of the inner surface 316. The convex portion abuts the non-fluid body 205.

[0089] In general, either or both of the first and second transparent cover members 211, 212 may be configured to have a concave or convex shaped portion 330 that forms part of the inner surface 316 and abuts the non-fluid body 205. For example, the concave shaped portion 330 advantageously provides a dome shaped feature that provides mechanical support to the opposing cover member and thus assists in controlling bending. The dome shape may be designed to at least partially act as a mold for the shape of the opposing cover member. Additionally, the dome shaped or convex protrusion may allow for greater deformation of the opposing cover member.

[0090] 4A primarily illustrates the relationship between a control or power signal 401 applied to the actuator 160 and the resulting optical power 402, represented by curve 405. Curve 405 illustrates that the optical power may be continuously varied from a minimum to a maximum value. The lens 101 may be configured to provide a change from the minimum to the maximum optical power of up to 3, up to 5, or even up to 7 diopters. Thus, the optical power may be continuously adjusted according to the ocular needs of the user.

[0091] In other situations, for example to provide spectacles 100 that resemble conventional spectacles, a continuous change in refractive power may not be desirable. Thus, the control system 150 may be configured to shift between predefined refractive powers of the spectacle lens 101. FIG. 4A shows that the lens 101 can be controlled to provide two predefined refractive powers 413, 414 by controlling the actuators with two values ​​403, 404 of a control or power signal. The values ​​403, 404 may be predetermined, determined as a function of other data, or determined via a feedback function. Thus, one or more actuators may be controllable to generate at least two predefined refractive powers of the lens 101.

[0092] 4B illustrates an optical error 406, such as a wavefront distortion error or aberration error, represented by curve 407, as a function of the control or power signal 401. As shown, the optical error 406 is minimized for two values ​​of the control or power signal 401 corresponding to two values ​​of the optical power 402. The optical error 406 may be minimized for two or more optical powers by optimizing the pre-shaped curvatures of the first and second cover members 211, 212 to provide the minimum optical error at the desired predetermined optical powers 413, 414.

[0093] The control or power signals, i.e., control signals used indirectly to control the actuators or power signals used directly to power the actuators, may be predetermined, i.e., a predetermined relationship may be used between one or more values ​​of the control or power signals and the corresponding optical power 402. This relationship may be stored in a memory included in the control circuit 150.

[0094] As the resulting optical force may depend on various factors such as temperature, actuator usage history, life, and other parameters, the control or power signal may alternatively be determined as a function of measurement data such as measured temperature, measured capacitance in the case of a piezoelectric based actuator 160, measured change in displacement amplitude over time, etc.

[0095] The glasses 100 may be configured with a distance sensor capable of measuring the distance between the lens 101 and an object that the user of the glasses 100 is looking at. Such a sensor may be a time-of-flight sensor or other. In this case, the control or power signal may be determined as a function of the error between the desired refractive power of the glasses lens and measurement data relating to the desired actual refractive power, such as the measured distance. Eye tracking may be implemented in the glasses to track the gaze direction. Such eye tracking may be used in combination with a distance sensor to determine which distance should be measured and thus accurately determine the distance and the associated refractive power.

[0096] The actuator 160 may be a linear displacement motor, such as a linear piezoelectric motor or an electromagnetic linear motor. A piezoelectric motor may be advantageous as it can maintain the achieved displacement of the linear output member when no power is supplied to the motor. Thus, the curvature of the first or second transparent cover member 211, 212 may be maintained in the unpowered state, i.e. when no power is supplied to the motor. This has the advantage of reducing power consumption, since power is mainly required when the optical power is changed.

[0097] The control circuit 150 may include electronic circuitry and / or a digital processor that generates the control or power signals, optionally obtains measurement data for determining the control or power signals, and may control the actuators using feedforward or feedback control algorithms.

Claims

1. - a first transparent cover member (211) and a second transparent cover member (212), said first cover member having a proximal surface (213) arranged to face the eye in use and said second cover member having a distal surface (214) arranged to face the environment in use; - one or more actuators (160) arranged to generate a force or torque on said first cover member or said second cover member (211, 212) so as to generate a controllable change in curvature of said first or second cover member; a transparent, deformable, non-fluid body (205) sandwiched between said first and second transparent cover members, one of the first and second transparent cover members, on which the actuator or actuators act, is supported on a distal or proximal surface, respectively, by a sliding contact (304) that allows displacement of the distal or proximal surface relative to the actuator or actuators (160); A spectacle lens (100).

2. the proximal surface (213) and / or the distal surface (212) are curved inwardly when viewed from the eye; The eyeglass lens of claim 1 .

3. One of the first and second transparent cover members on which the one or more actuators act is bendable by a force generated by the one or more actuators; the other of the first and second transparent cover members being shaped to provide a static optical correction. The eyeglass lens according to claim 1 or 2.

4. the spectacle lens is arranged to allow the non-fluid body to expand unconstrained within an annular volume (301) located between the first transparent cover member and the second transparent cover member and surrounding the non-fluid body; The spectacle lens according to any one of claims 1 to 3.

5. The spectacle lens is arranged such that external light traveling through the spectacle lens toward the eye is refracted through a sandwich structure consisting of the first and second transparent cover members, the non-fluid body, and optionally an optical coating on the distal surfaces of the first and second transparent cover members.

5. The spectacle lens according to claim 1.

6. at least one of the first and second transparent cover members has an initial curved shape that causes the spectacle lens to have a non-zero optical power when one or more of the actuators apply zero or minimal force to the first or second cover members; 6. A spectacle lens according to claim 1.

7. At least one of the first and second transparent cover members has a concave or convex portion that abuts the non-fluid body.

7. A spectacle lens according to claim 1.

8. the actuator or actuators are controllable to generate at least two predetermined optical powers (413, 414) of the spectacle lens; 8. A spectacle lens according to any one of claims 1 to 7.

9. the spectacle lens is optimized to produce a minimum optical error (406) at said at least two predetermined refractive powers; 9. The eyeglass lens according to claim 8.

10. The actuator or actuators are controlled via a control or power signal, the control or power signal being determined as a function of measured data.

10. A spectacle lens according to any one of claims 1 to 9.

11. the actuator or actuators are controlled via a control signal, the control signal being determined as a function of an error between a desired refractive power of the spectacle lens and measurement data relating to an actual refractive power.

11. A spectacle lens according to any one of claims 1 to 10.

12. The actuator is a linear displacement motor capable of maintaining an achieved curvature of the first or second transparent cover member in an unpowered state.

12. A spectacle lens according to any one of claims 1 to 11.

13. the minimum diameter of a line extending from one edge of the spectacle lens to the opposite edge and intersecting the center point of the spectacle lens is 15 mm; 13. A spectacle lens according to any one of claims 1 to 12.

14. The sliding contact (304) is having one or more elastic elements (601) connecting one or more of said actuators (160) to said distal face and / or said proximal face (213, 214); 14. A spectacle lens according to any one of claims 1 to 13.

15. at least one spectacle lens according to claim 1, - a power and control circuitry for powering and controlling said actuator(s); Glasses equipped with

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