Adjustable focal length lens and eyeglass device employing the same

Abstract

An adjustable focus eyewear device comprising: at least one lens mounted on a frame to support the lens in front of a user's eye to define a viewing direction through the lens; wherein the at least one lens is a variable focus lens of the type comprising two superposed lens elements having cooperating optical surfaces shaped such that the focal length of the lens is variable according to the relative lateral arrangement of the lens elements in a direction transverse to the viewing direction; wherein the lens elements are slidable relative to each other along a lateral path oriented transversely to the viewing direction to vary the focal length of the lens; wherein the lens further comprises: guiding means on the lens elements cooperating with each other to limit the relative lateral movement of the lens elements to the lateral path; and a magnetic fastener for releasably fastening the lens elements to each other, the magnetic fastener comprising an elongate magnetic strip provided on or fixed with a part of one of the lens elements; and a cooperating magnetic slider provided on or fixed with a part of the other lens element, wherein the magnetic slider and the magnetic strip are configured and arranged to: during reciprocating relative lateral movement of the lens elements along the lateral path, fasten the lens elements to each other by magnetic force, and allow the lens elements to be disassembled from each other in the viewing direction.

Description

Technical Field

[0001] This application relates to an adjustable focal length eyeglass device comprising at least one variable focal length lens of the type described below, comprising two stacked lens elements having mutually cooperating optical surfaces shaped such that the focal length of the optical lens can be changed according to the relative lateral arrangement of the two lens elements in a direction transverse to the viewing direction. Background Technology

[0002] Optical lenses of the type described above are well known in the art. Adjustable optical lenses of this type typically comprise two stacked lens elements having mutually cooperating cubic or higher-order curved surfaces and an opposing arrangement that can be varied in a lateral direction relative to the direction of observation through the lens to alter the lens's optical power. Suitablely, this lateral direction can extend in a plane that is generally horizontal to the user's position under normal use; however, in some instances of such lenses, this direction may also extend in the sagittal plane, or at least theoretically, in any other plane having a component substantially perpendicular to the direction of observation. An example of such an adjustable lens is the Alvarez lens disclosed in U.S. Patent 3,305,294A, the contents of which are incorporated herein by reference.

[0003] While adjustable eyeglasses in this field generally operate satisfactorily, the adjustment mechanisms used to adjust the optical power of the lenses are often bulky and aesthetically unappealing. A common problem with eyeglasses containing such adjustable lenses is that the additional components required for lens adjustment increase the weight of the glasses. Furthermore, the continuous adjustment of the focal length or optical power of a pair of lenses can be uncomfortable for the user, especially when unnecessarily changing the optical power during use.

[0004] One object of this application is to provide a pair of eyeglasses or other wearable vision correction devices with adjustable focal lengths that are more aesthetically appealing than similar eyeglass devices known in the prior art. Another object of this application is to provide an eyeglass device (e.g., corrective glasses) with adjustable focal lengths in which the user can selectively adjust the lens between two or more discrete focal lengths using a simple manual adjustment mechanism. Summary of the Invention

[0005] A first aspect of this application relates to an adjustable-focus eyeglasses device comprising at least one lens mounted on a frame to support the lens in front of a user's eyes, thereby defining the direction of observation through the lens. The at least one lens is a variable-focus lens of the type comprising two stacked lens elements having cooperating optical surfaces shaped such that the focal length of the variable-focus lens can be changed according to the relative lateral arrangement of the lens elements in a direction transverse to the observation direction. The lens elements can slide relative to each other along a lateral path oriented transverse to the observation direction to change the focal length of the lens.

[0006] The lens of this application further includes: cooperative guide members on the lens elements that restrict relative lateral movement of the lens elements within the lateral path; and magnetic fasteners for releasably securing the lens elements to each other. The magnetic fasteners include an elongated magnetic strip disposed on one of the lens elements or a component fixedly connected thereto; and a cooperative magnetic slider disposed on the other lens element or a component fixedly connected thereto. The magnetic slider and magnetic strip are configured and arranged to: magnetically secure the lens elements to each other during reciprocating relative lateral movement of the movable lens elements along the lateral path, and allow the movable lens elements to be disassembled from each other in the viewing direction.

[0007] Preferably, although the guide members on the lens element restrict the relative lateral movement of the lens element to a lateral path, they allow the lens elements to overcome the attraction of the magnetic fasteners and separate from each other along the viewing direction at at least one relative lateral position of the lens element (preferably at all relative positions of the lens element).

[0008] Advantageously, the magnetic fasteners prevent the lens elements from accidentally disengaging from each other when the lens elements are moved relative to each other. Additionally, the magnetic fasteners allow the lens elements to be disassembled from each other when necessary. This can be used for cleaning, repairing, or replacing the lens elements.

[0009] A first lens element (or "one" or "the other") may be fixedly attached to the frame. A second lens element (or "one" or "the other") may be movable relative to the first lens element and the frame. The first lens element may be conveniently mounted on the frame. For example, the first lens element may be surrounded by a frame edge that restricts the lens element. Typically, the first lens element may be a front lens element, and the second lens element may be a rear lens element. When the eyeglasses are actually worn by the user, the front lens element may be the lens element furthest from the eye, and the rear lens element may be the lens element closest to the eye. The second lens element may be positioned behind the frame in the direction of observation.

[0010] Adjustable focus eyeglasses may include a lens element positioning mechanism. The positioning mechanism may define multiple discrete relative positions of the lens element along a lateral path. The positioning mechanism may be arranged to constrain the lens element (laterally) at each discrete relative position. The positioning mechanism may be arranged such that, when the lens element is not in any discrete relative position, the lens element is biased toward one of the discrete relative positions (e.g., the nearest discrete relative position). Without external force (e.g., applied by the user), the lens elements can thus move relative to each other to occupy one of the discrete relative positions. The biasing force may suitably be provided by a magnetic fastener that can push the lens elements together. The magnetic fastener can constrain the lens element in a direction generally parallel to the viewing direction.

[0011] At each discrete relative position, the lens provides a different focal length. These discrete relative positions are typically spaced apart, such that the focal length varies by 0.5 diopters or 1 diopter between each discrete relative position. A positioning mechanism allows the user to select the lens's focal length by holding the lens element at a discrete relative position corresponding to the selected focal length. Therefore, the user can select a specific lens setting according to their needs; for example, a larger diopters may be needed for reading compared to computer work.

[0012] The positioning mechanism can be a manual positioning mechanism, that is, a positioning mechanism operated manually by the user of the eyewear device. The positioning mechanism may not contain any electromechanical actuators.

[0013] The positioning mechanism may include a first positioning member associated with (e.g., formed therein or fixedly connected to) one of the lens elements, and a second positioning member associated with (e.g., formed therein or fixedly connected to) another lens element. When the lens elements are fastened together, the first and second positioning members may be arranged to mechanically engage with each other. This mechanical engagement may (e.g., in conjunction with the attractive force provided by a magnetic fastener) occupy and hold the lens elements in one of discrete relative positions (in the absence of external force, such as a force applied by a user). The magnetic fastener may provide a biasing force that biases the first and second positioning members toward the mechanical engagement. Advantageously, the magnetic fastener is used to hold the lens elements together in all relative positions (including between discrete relative positions).

[0014] The positioning mechanism may appropriately include multiple first positioning components and corresponding multiple second positioning components.

[0015] The first (or second) positioning component can be defined on the rear surface or frame of the front lens element, and the second (or first) positioning component can be defined on the rear surface of the rear lens element. The magnetic force between the magnetic slider and the magnetic strip, acting magnetically, secures the lens elements together, with its direction of action substantially parallel to the viewing direction. The first and second positioning components can thus be pushed into engagement by the magnetic force between the magnetic slider and the magnetic strip.

[0016] The first positioning component may include a snap fastener, while the second positioning component may include a series of recesses. The snap fastener may extend generally in the viewing direction. The series of recesses may be defined by a ridged surface (e.g., the front surface of a rear lens element) of a corresponding lens element oriented generally perpendicular to the viewing direction. When the lens elements are fastened to each other, the snap fastener may selectively engage one of the recesses to laterally constrain the lens element to one of (e.g., selected) discrete relative positions. The position of the recesses relative to the snap fastener may define discrete relative positions along a lateral path. To change the focal length of the lens, the user may apply a force to move the lens elements relative to each other along a lateral path. As the lens elements move, the snap fastener may ride on the recesses. When the force applied by the user is removed, the snap fastener may be positioned (e.g., under the biasing force provided by a magnetic fastener) in an adjacent recess such that the lens elements remain in the desired discrete relative positions.

[0017] The positioning mechanism may include a stop device. The stop device may define a series of stop positions corresponding to discrete relative positions after disassembly. The stop device may include: a first stop component, for example formed by the snap-fit; and a second stop component, for example formed by the series of grooves.

[0018] Cooperative guide components may include a first guide component associated with (e.g., formed therein or fixedly connected to) one of the lens elements, and a corresponding second cooperative guide component associated with (e.g., formed therein or fixedly connected to) another lens element. The first and second guide components restrict relative movement of the lens elements within a lateral path. For example, the first guide component may be or may include a guide pin, and the second guide component may be or may include a slot (e.g., forming a slide), the slot being configured to receive the guide pin such that the guide pin can slide within the slot. The slot may be configured to restrict movement of the guide pin in the lateral direction. The slot may be elongated, and its length extends in a direction generally perpendicular to the viewing direction.

[0019] In some embodiments, the guide pin and slot may be configured to retain the pin within the slot in one or more opposing positions of the lens element, thereby preventing the lens elements from being disassembled from each other while allowing such disassembly to be performed in one or more other opposing positions. For example, the guide pin may include an enlarged head that engages with one or more retaining ribs extending along a portion (but not all) of the slot length. However, in a preferred embodiment, the guide pin and slot are configured to allow the guide pin to be removed from the slot in all opposing positions of the lens element.

[0020] In various embodiments, the cooperating guide components also form (e.g., are provided) part of the lens element positioning mechanism described above. The first and / or second guide components may form (e.g., are provided) part of the lens element positioning mechanism. For example, the first positioning component may include a guide pin. The guide pin may form a snap-fit. A slot may provide a second positioning component. The second positioning component may include a surface of the slot comprising a series of grooves that engage with the guide pin (snap-fit) to form the positioning mechanism described above.

[0021] There may be multiple cooperating guide components, for example, spaced apart in a lateral direction. For example, there may be multiple first guide components and corresponding multiple second guide components. For example, there may be multiple slots, each slot including a corresponding guide pin. One or more cooperating guide components may form part of a positioning mechanism.

[0022] Adjustable focus eyeglasses may include two or more sets of cooperating guide components spaced apart in the direction of the lateral path. This helps prevent lens elements from rotating relative to each other, for example, about an axis extending generally in the viewing direction through the lens. In particular, the guide components can be spaced apart for use in conjunction with magnetic fasteners to hold the lens elements together stably. The cooperating guide components can be arranged to minimize the tendency of the lens elements to twist, wobble, or otherwise move relative to each other in directions other than the lateral path.

[0023] Cooperative guide components can provide the aforementioned stop device. For example, a first stop component provided by a first guide component can be present on a (e.g., movable) lens element, which engages with a second stop component provided by a second guide component on a (e.g., fixed) lens element or frame. When a gradually increasing force is applied in one direction (causing the movable lens element to move along a lateral path and relative to the fixed lens element), the engaged stop components may initially impede the movement of the movable lens element, holding the lens element in a first discrete relative position (stop position). Eventually, the applied force may be sufficient to overcome the resistance, thereby enabling the lens element to move along a lateral path and engaging the cooperating guide components in a second discrete relative position (stop position).

[0024] As described above, the lens element is configured to provide a different predetermined focal length at each discrete relative position (stopper position). In a readily understandable example, the focal length can provide refractive power of -1.0 D, -0.5 D, 0 D, +0.5 D, and +1.0 D. In another embodiment, the focal length can provide refractive power of 0 D, +0.5 D, +1.0 D, +1.5 D, and +2 D. More generally, the optical power of the lens can be adjusted between 0 D and +4 D. In some embodiments, the minimum additional refractive power provided by the lens can be +0.25 D or +0.5 D.

[0025] Those skilled in the art will understand that, at each relative lateral position of the lens element, the variable focal length lens defines an optical (z) axis, that is, an axis substantially perpendicular to the lens and representing the path of light rays as they pass through the lens without a net change in direction. For convenience, the lens element can be arranged such that when the focal length of the lens decreases, the optical axis of the lens shifts inward (i.e., toward the user's nose), and conversely, when the focal length of the lens increases, the optical axis of the lens shifts outward (i.e., toward the user's temple). This design corresponds to how the eye moves to focus from far to near and can help improve the user's optical experience.

[0026] The positioning mechanism can define at least two or three selectable discrete relative positions of the lens element along the lateral path. The adjustment mechanism can define three, four, or five selectable discrete relative positions of the lens element along the lateral path. It should be noted that the adjustment mechanism can define more than five or fewer discrete relative positions, depending on the optical power requirements of the variable focal length lens.

[0027] The lateral path may have two opposing lateral endpoints that the lens element cannot cross. The endpoints of the lateral path may be defined by cooperating guide components. For example, the endpoints may be defined by the end of a slot that receives a guide pin.

[0028] The variable focal length lens is adjustable to change the optical power of the lens, with an adjustment range of approximately +3.0 diopters, suitable for most users who need to change the optical power between near reading and far viewing. In some embodiments, each discrete stop may define + / - 0.5 diopters. In some embodiments, a wider range of variation can be provided, for example, each stop may define + / - 1, 2, 3 diopters, which facilitates the manufacture of lens elements with fewer discrete stops.

[0029] Cooperative guide components can define a lateral path that is either straight or curved. In some embodiments, the optical surfaces of the lens element can be formed on a base curve in a manner known to those skilled in the art. Thus, in some embodiments, the lateral path is not a straight line, but can be arcuate in a plane defined by the viewing direction and a horizontal (x) axis that substantially corresponds to the optical (z) axis in each relative position of the lens element, the horizontal (x) axis being substantially perpendicular to the optical (z) axis and extending between the temporal and nasal sides of the lens, such that the movement of the movable lens element along the lateral path substantially follows the base curve.

[0030] Magnetic sliders and magnetic strips are configured and arranged such that, when the lens elements are moved relative to each other along a lateral path, the magnetic sliders slide relative to (e.g., along their length) the magnetic strips, thereby holding the lens elements magnetically fastened to each other. Magnetic fasteners can hold the lens elements magnetically fastened to each other throughout the entire range of relative movement of the lens elements between adjacent discrete relative positions. Magnetic fasteners can magnetically fasten the lens elements together throughout the entire range of relative movement of the lens elements along the lateral path (i.e., between lateral endpoints). Magnetic fasteners can be configured to provide a holding force substantially independent of the relative position of the lens elements. The positioning of the discrete relative positions of the lens elements along the lateral path can be independent of the magnetic fasteners.

[0031] Advantageously, the magnetic fasteners can securely hold the lens elements together, allowing them to move relative to each other along a lateral path. Suitably, the magnetic fasteners are strong enough to firmly hold the lens elements together during use, while allowing the user to move the lens elements relative to each other between discrete stop positions defined by the positioning mechanism. Additionally, the magnetic fasteners allow the movable lens elements to be removed when needed; for example, by pulling, pushing, or lifting the lens to overcome the magnetic attraction that holds the lens elements together. Those skilled in the art can select magnetic fasteners of suitable strength to control the holding force and sliding friction between the lens elements.

[0032] It should be noted that only one of the magnetic strip and the magnetic slider needs to be permanently magnetized (i.e., become a magnet); the other component may include a magnetic material (e.g., a magnet material) that is attracted to the magnetized component by magnetic force. In some embodiments, both the magnetic strip and the magnetic slider can be magnetized (their poles facing each other). The magnetic axis of the magnetic slider and / or the magnetic axis of the magnetic strip are preferably substantially perpendicular to the plane in which the magnetic slider slides relative to the magnetic strip.

[0033] An elongated magnetic strip may be disposed on one of the lens elements or on the frame. The elongated magnetic strip may be generally rectangular in shape and have a length extending generally in the lateral direction. In some embodiments, the elongated magnetic strip may be disposed on the lens element or frame by overmolding during the manufacturing process of the lens element or frame. The lens element or frame may include recesses configured to securely hold the elongated magnetic strip.

[0034] Similarly, the magnetic slider can be disposed on one of the lens elements or on the frame. The cooperating magnetic slider can be disc-shaped or dovetail-shaped, with its magnetic axis extending generally toward the magnetic strip in the viewing direction. In some embodiments, the magnetic slider can be disposed on the lens element or frame by molding it into the lens element or frame during the manufacturing process. The lens element or frame may include recesses configured to securely hold the magnetic slider. In some embodiments, the magnetic slider can be fixed within the recesses, for example, using a suitable adhesive.

[0035] When the user moves the lens elements relative to each other, the magnetic slider moves relative to the thin magnetic strip.

[0036] Magnetic fasteners can be positioned behind the frame and can be stacked with the frame. Preferably, when viewed from the front, the magnetic fasteners are completely contained within the outline of the solid components of the frame. This helps to conceal the magnetic fasteners from view when the user is actually wearing the eyeglasses. Ideally, the guide components and positioning mechanisms are also arranged in a similar manner so that they are hidden when the eyeglasses are viewed from the front.

[0037] At least two magnetic fasteners can be spaced apart (e.g., vertically) in a top-to-bottom direction from the user's perspective (i.e., in a direction substantially perpendicular to both the lateral and viewing directions). This helps to stabilize the lens elements relative to each other in the viewing direction and prevents the lens elements from rotating relative to each other about the optical axis. In some embodiments, only one magnetic fastener is used for each lens.

[0038] In some embodiments, the eyewear device may include a pair of variable focal length lenses as described above. In some embodiments, the eyewear device may be a pair of eyeglasses (i.e., corrective lenses) or goggles. In some embodiments, the eyewear device may be a head-mounted device, such as a head-mounted display for augmented or virtual reality.

[0039] A pair of lenses according to this application (e.g., as described above) can be mounted in a frame to form the eyeglasses. The frame may be frameless or may include at least one frame edge portion to provide support around the periphery of each lens. The frame may include temples and a bridge. In some embodiments, the lenses may be mounted on the frame such that both lens elements are movable relative to the frame. In some embodiments, the two lens elements may be interconnected to move in opposite directions along a lateral path by equal amounts. In this case, regardless of how the relative arrangement of the lens elements changes, the position of the optical axis relative to the frame will remain substantially fixed.

[0040] At least one lens element may include a engagement portion for engagement by a user to allow movement of the lens elements relative to each other and / or to allow disassembly of the lens elements from each other. For convenience, the engagement portion may extend beyond the outer perimeter of the frame. For example, the engagement portion may extend below a lower region of the frame edge portion. The engagement portion may include a ridged surface. This improves the grip provided by the engagement portion.

[0041] A second aspect of this application relates to a variable focal length lens comprising two stacked lens elements (i.e., stacked relative to each other in the observation direction) having cooperative optical surfaces shaped such that the focal length of the lens can be varied depending on the relative lateral arrangement of the lens elements in a direction transverse to the observation direction. The lens elements can slide relative to each other along a lateral path oriented transverse to the observation direction to change the focal length of the lens.

[0042] The lens also includes: cooperative guide members on the lens elements that restrict relative lateral movement of the lens elements within a lateral path; and magnetic fasteners for releasably securing the movable lens elements to each other. The magnetic fasteners include an elongated magnetic strip disposed on or fixedly connected to one of the lens elements; and a cooperative magnetic slider disposed on or fixedly connected to the other lens element. The magnetic slider and magnetic strip are configured to: magnetically secure the lens elements to each other during reciprocating relative lateral movement of the movable lens elements, and allow the movable lens elements to be disassembled from each other in the viewing direction.

[0043] The lens may have any of the features described in the first aspect of this application. For example, the lens may include the lens element positioning mechanism as described above.

[0044] This application also provides a vision correction device comprising at least one adjustable lens and a wearable bracket for fixing the adjustable lens in front of a user's eyes; the adjustable lens comprises two lens elements stacked one behind the other in the direction of observation through the adjustable lens and configured such that the optical power of the adjustable lens can be varied by laterally offsetting the lens elements relative to each other; wherein the lens elements or components fixedly connected thereto have mutually cooperating guide members for limiting the relative lateral movement of the lens elements to a path laterally to the direction of observation; at least one lens element or component fixedly connected thereto includes an elongated magnetic strip extending in the lateral direction; the other lens element includes at least one magnetic slider that is magnetically attracted to the magnetic strip, thereby fixing the two lens elements together while allowing the relative lateral movement and allowing the lens elements to be disassembled from each other by overcoming the magnetic force between the slider and the magnetic strip.

[0045] It should be understood that features described with respect to one aspect of this application may be incorporated into other aspects of this application. For example, the method of this application may include any features described with reference to the apparatus of this application, and vice versa.

[0046] The following description is illustrative only, with reference to the accompanying drawings of embodiments of this application. Attached Figure Description

[0047] In the attached diagram: Figure 1 This is a front view of framed glasses according to a first embodiment of the present application. The framed glasses include a frame and two variable focal length lenses of the following type, wherein the lenses include a front lens element and a rear lens element, which are arranged to move laterally relative to each other to adjust the optical power of the lenses. Figure 2 yes Figure 1 A top view of framed glasses; Figure 3 Viewed from above and from the left Figure 1 A perspective view of the front of the eyeglasses, showing the rear lens element of the variable focal length lens detached from the cooperating front lens element.

[0048] Figure 4 Viewed from above and from the left Figure 1-3 An exploded perspective view of the back of the glasses; Figure 5 yes Figure 1-4 A rear view of the left side of the glasses, showing the rear lens element engaged with the frame in use; Figure 6 This is a perspective view of the left rear lens element as seen from above and from the right. Figure 7 This is a perspective view of the left front lens element mounted in the eyeglass frame, viewed from above and from the left. Figure 8 This is an enlarged view of the upper frame of the eyeglasses frame, showing the magnetic fasteners and guide pins used when the rear lens element is mounted to the frame and the front lens element. Figure 9 This is an enlarged view of the lower frame of the eyeglasses, showing the magnetic fasteners and positioning mechanisms when the rear lens element is mounted to the frame and the front lens element. Figure 10a These are enlarged views of the lower frame and magnetic fasteners of the eyeglasses frame; and Figure 10b This is an enlarged view of the lower frame of the rear lens element and the cooperating part of the magnetic fastener and positioning mechanism. Detailed Implementation

[0049] Figures 1 to 4 This invention illustrates an adjustable-focus eyeglasses device according to a first embodiment of the present application. The adjustable-focus eyeglasses device is in the form of a pair of framed glasses 100; however, in other embodiments, the eyeglasses device may include another type of eyeglasses device, such as a head-mounted device, goggles, safety glasses, etc.

[0050] The eyeglasses 100 include two variable focal length lenses 21 and 22 mounted in a frame 12. The frame 12 includes a front portion 13, which includes a left frame portion 17 and a right frame portion 18, as well as an integrated bridge portion 14. The frame 12 also includes left and right temples 15 and 16, each conventionally hinged to a corresponding one of the frame portions 17 and 18.

[0051] The variable focal length lenses 21 and 22 each include two stacked lens elements 31 and 41 of the following type, which are arranged to slide relative to each other along a lateral path in a direction perpendicular to the viewing direction to adjust the focal power of lenses 21 and 22. This type of lens includes Alvarez-type lenses.

[0052] Lenses 21 and 22 each include front and rear lens elements 31 and 41, respectively. The front lens element 31 of each lens 21 and 22 is fixedly connected to the corresponding frame portion 17 and 18, while the rear lens element 41 is... Figure 2 and Figure 4 The x-axis can slide relative to the front lens element 31 in the direction indicated by the x-axis. The x-axis extends across the observation direction. The observation direction is usually indicated by the z-axis.

[0053] In some embodiments, the frame 12 and the front lens element 31 of the lenses 21, 22 are integrally formed. In other embodiments, the frame 12 and the front lens element 31 of the lenses 21, 22 are formed as three parts (frame, left front lens element, right front lens element) and assembled in a conventional manner (e.g., using conventional chamfer fit).

[0054] In some embodiments, the front and rear lens elements 31 and 41 are formed with basic curves in a manner known in the art, so that when the rear lens element 41 moves relative to the front lens element 31, the lateral path it follows is curved rather than straight in the xz plane. However, in the embodiments of this application, the lateral path follows a substantially straight trajectory.

[0055] The left and right lenses 21 and 22 are essentially the same in structure and operation, the difference being that one lens is a mirror image of the other in the intermediate yz plane (not shown) that bisects the bridge 14 of the frame 12. Therefore, only the left lens 21 is described in detail below, but this description also applies to the right lens 22.

[0056] like Figure 4 As shown, the front lens element 31 has a front surface 32 and a rear surface 33. The front lens element 31 is generally rectangular, but it has curved sides and corners. Figure 7 As shown, the anterior lens element 31 has a top edge 34, a bottom edge 35, a temporal edge 36, and a nasal edge 37. The top edge 34 of the anterior lens element 31 is mounted in the upper part 4 of the frame edge portion 17, while the bottom edge 35 of the anterior lens element 31 is mounted in the lower part 5 of the frame edge portion 17. The temporal and nasal edges 36 and 37 of the anterior lens element 31 are respectively mounted in the corresponding temporal and nasal portions 6 and 7 of the frame edge portion 17 of the frame 12.

[0057] like Figure 5 , Figure 7 and Figure 8 As shown, the upper part 4 of the frame edge portion 17 of the frame 12 is provided with two upper guide pins 81, 82, which are spaced apart in the x-direction. The upper guide pins 81, 82 protrude rearward from the rear surface of the frame edge portion 17. Between the two upper guide pins 81, 82, on the rear surface of the upper part 4 of the frame edge portion 17, an upper magnetic strip 48 is provided. The upper magnetic strip 48 is formed of a ferromagnetic material such as steel, is elongated, and is substantially rectangular, with its length extending in the x-direction. The upper magnetic strip 48 is fixed inside the upper part 4 of the frame edge portion 17 so that it is not visible when the glasses are viewed from the front. In alternative embodiments, the upper magnetic strip 48 may have different shapes; for example, the upper magnetic strip may be elliptical. In some embodiments, the upper magnetic strip 48 is mounted flush with the rear surface of the upper part 4 of the frame edge portion 17.

[0058] like Figure 5 , Figure 7 , Figure 9 and Figure 10a As shown, the lower part 5 of the frame edge portion 17 has a component arrangement similar to that of the upper part 4 of the frame edge portion 17. A lower magnetic strip 49 is fixed at approximately the center of the lower part 5 of the frame edge portion 17. The lower part 5 of the frame edge portion 17 has two lower guide pins 91 and 92, located on either side of the lower magnetic strip 49. The lower guide pins 91 and 92 are aligned with the upper guide pins 81 and 82. The lower guide pins 91 and 92 protrude rearward from the rear surface of the frame edge portion 17 in the same manner as the upper guide pins 81 and 82.

[0059] like Figure 4 As shown, the rear lens element 41 has front and rear surfaces 42 and 43, and its shape is similar to that of the front lens element 31. Figure 6 As shown, the rear lens element 41 has a top edge 44, a bottom edge 45, and temporal and nasal edges 46, 47. In some embodiments, the width of the rear lens element 41 between the temporal and nasal edges 46, 47 is greater than the corresponding width of the front lens element 31.

[0060] like Figure 1 , 5 As shown in Figure 9, the front lens element and the rear lens element 31, 41 are mounted such that at least one engaging portion 78 of the bottom edge 45 of the rear lens element 41 protrudes slightly downward from the bottom edge 5 of the frame 12, at least partially, to facilitate manual movement of the rear lens element 41 relative to the front lens element 31 and to assist in completely disassembling the rear lens element 41 from the front lens element 31. As Figure 5 , Figure 9 and Figure 10b As shown, the bottom edge 45 of the rear lens element 41 has a wavy (i.e., ridge-like) engagement portion 78. By increasing the friction between the user's hand and the rear lens element 41, the engagement portion 78 makes the lens 21 easier for the user to operate.

[0061] Reference Figure 6 The rear lens element 41 has two tapered shoulders 51, 52 formed near its top edge 44. In embodiments of this application, the tapered shoulders 51, 52 are formed on the front surface 42 of the rear lens element 41 and oriented along the x-axis. The tapered shoulders 51, 52 are defined by corresponding recesses in the front surface 42 of the rear lens element 41 and arranged to engage with guide pins 81, 82; therefore, the tapered shoulders are configured to have a depth corresponding to the height of each guide pin 81, 82 in the z-axis direction. In other embodiments, the tapered shoulders 51, 52 may extend completely through the rear lens element 41. Figure 5 and Figure 8As shown, the tapered shoulders 51 and 52 are each arranged to slidably engage with a corresponding sliding engagement guide pin 81 and 82. It should be noted that, in one variant, a guide pin may instead be formed on the rear lens element 41, protruding forward and engaging with a corresponding shoulder in the front lens element 31. Alternatively, the tapered shoulders may be replaced by an elongated slot or channel (not shown).

[0062] Between the two shoulders 51, 52, the front surface 42 of the rear lens element 41 has a protrusion 60 that protrudes from the front surface 42 along the z-direction, such as Figure 6 The diagram is most clearly shown. The protrusion 60 has a recess that accommodates the upper magnetic slider 58. Suitably, the magnetic slider is bonded to the recess by an adhesive. In other embodiments, there is more than one protrusion, each having a recess that accommodates the magnetic slider. The upper magnetic slider 58 is made of a permanent magnet material with its magnetic axis oriented along the z-axis for coupling with the upper magnetic strip 48 in the upper portion 4 of the frame 12, as described in detail below.

[0063] In an alternative implementation, the protrusion 60 may be absent, and the upper magnetic slider 58 may be flush with the front optical surface of the rear lens element 41.

[0064] The front surface 42 of the rear lens element 41 also has a recess 57 near the bottom edge 45, which is perpendicularly aligned with the protrusion 60. The recess 57 accommodates the lower magnetic slider 59 (e.g., Figure 5 , Figure 9 ,and Figure 10b As shown, the slider is also bonded to the recess 57 with a suitable adhesive and has a magnetic axis oriented along the z-axis for coupling with the lower magnetic strip 49. The lower magnetic slider 59 is flush with the front optical surface of the rear lens element 41.

[0065] This embodiment allows for smaller dimensions of the upper and lower rear magnetic sliders 58, 57 compared to the upper and lower front magnetic strips 48, 49, enabling the rear movable lens element 41 to be manufactured with a minimal number of components. This reduces the weight of the lens element, and therefore, the glasses 11 can be made thinner and smaller compared to some other conventional adjustable lenses in the art. Keeping the product as close as possible to the weight of conventional eyeglasses is crucial for ensuring user comfort and familiarity. Additionally, the lightweight rear lens element 41 facilitates rapid adjustment of the rear lens element 41 relative to the front lens element 31 along a lateral path.

[0066] The upper magnetic strip 48 and the upper magnetic slider 58 together form the upper magnetic fastener 20. The lower magnetic strip 49 and the lower magnetic slider 57 together form the lower magnetic fastener 40. The magnetic fasteners 20 and 40 magnetically fasten the front lens element and the rear lens element 31 and 41 together with sufficient holding force to keep the lens elements 31 and 41 together. This magnetic force is strong enough to keep the rear lens element 41 fastened to the front lens element 31 and the frame 12 under various conditions that may be encountered during normal use of the glasses. In addition, the magnetic fasteners 20 and 40 allow the rear lens element 41 to slide laterally relative to the front lens element 31 and the frame 12 without falling off, and allow the rear lens element 41 to be manually removed from the front lens element 31 and the frame 12 by pulling the front lens element and the rear lens element 31 and 41 apart in the z-axis direction, for example, when it is necessary to clean the lens elements 31 and 41.

[0067] The rear lens element 41 has two elongated slots 61, 62 near its bottom edge 45, oriented along the x-axis and located on either side of the lower magnetic slider 59. In embodiments of this application, the slots 61, 62 are elliptical, but in other embodiments, the slots may have another shape. The elongated slots 61, 62 are formed by recesses in the front surface 42 of the rear lens element 41. Each elongated slot 61, 62 is arranged to receive a corresponding one of the lower guide pins 91, 92. The elongated slots 61, 62 are configured to have a certain degree, which corresponds to the height of the lower guide pins 91, 92 on the z-axis. It can be seen that the width of each slot 61, 62 is approximately equal to the diameter of each pin 91, 92, such that the engagement of the pins 91, 92 in the slots 61, 62 serves to stably press the rear lens element 41 onto the front lens element 31.

[0068] Guide pins 81, 82, 91, and 92 each form a first guide member associated with the front lens element 31. Channels 51 and 52 and slots 61 and 62 each form a second guide member associated with the rear lens element 41. The first and second guide members form cooperating guide members (a total of four sets of cooperating guide members) that restrict the relative lateral movement of the lens elements 31 and 41 to a lateral path. Guide pins 81, 82, 91, and 92 are not trapped within channels 51 and 52 and slots 61 and 62, which allows the rear lens element 41 to be easily detached from the front lens element 31 by pulling the rear lens element 41 against the magnetic force of the magnetic fasteners.

[0069] As Figure 9 and Figure 10bAs shown, within the temporal side slot 61, the inner anterior surface of the recess has a series of structures 102. Each structure 102 includes a protrusion 104 projecting forward along the z-axis toward the opening of the slot 61. The protrusion 104 forms a ribbed surface and defines a plurality of grooves distributed in the transverse direction, with a groove 106 between each protrusion 104.

[0070] The attractive magnetic force between the magnetic slider 59 and the magnetic strip 49 biases the lens elements 31, 41 into a position where the guide pin 91 is embedded in the groove 106. The engagement of the groove 106 with the guide pin 91 restricts the lateral movement of the rear lens element 31 relative to the front lens element 41. To move the rear lens element 41 relative to the front lens element 31, it is necessary to move the rear lens element 41 relative to the front lens element 31 and the frame 12 such that the guide pin 91 disengages from the groove 106 and rides on the protrusion 104. This requires the rear lens 41 to temporarily move in the direction opposite to the attractive magnetic force between the magnetic slider 59 and the magnetic strip 49. The protrusion 104 helps prevent the corresponding lower guide pin 91 from moving freely along the elongated slot 61, thus helping to stably hold the front and rear lens elements 31, 41 together and helping to control the movement of the rear lens element 41 when moving it between the temporal position, the middle position, and the bridge of the nose position.

[0071] Guide pin 91 and structure 102 form a lens element positioning mechanism. Guide pin 91 acts as a latch and forms a first positioning member. The series of grooves defined by structure 102 form a second positioning member. Magnetic force provided by a magnetic fastener biases the first and second positioning members into an engaged state. Guide pin 91 and structure 102 can be considered as forming a positioning mechanism in the form of a stop device.

[0072] Each groove 106 defines a corresponding discrete relative position (stopper position) of the lens elements 31, 41 along the lateral path. The number of grooves 106 defines the number of discrete relative positions that the adjustable lens can employ. Figure 9 and Figure 10b In the embodiment of this application shown, five grooves 106 are provided, which define five corresponding discrete positions where the guide pin 91 can be fixed, thereby allowing the lens elements 31, 41 to be positioned in five discrete relative positions along the lateral path. At each discrete relative position, the lens 21 has a different predetermined focal length. In this embodiment, the focal length differs by 1 diopter between each consecutive discrete relative position; however, in other embodiments, the difference may be different.

[0073] When a user applies force to move the rear lens element 41 relative to the front lens element 31, the protrusion 104 resists this movement. An audible sound, such as a click, is produced when the resistance of the protrusion 104 is overcome and the element moves into another recess 106. This provides auditory feedback to the user, allowing them to confirm that the rear lens element 41 has successfully moved from one recess to another. The movement of the guide pin 91 between the recesses 106 also provides positive tactile feedback to the user.

[0074] In embodiments of this application, the cross-section of the protrusion 104 is arc-shaped, but in other embodiments, the protrusion 104 may have a triangular or other shape to laterally restrict the guide pin 91 at discrete locations within the slot 61.

[0075] In embodiments of this application, only the temporal elongated slot 61 has a structure 102. It should be noted that the nasal elongated slot 62 may alternatively or additionally include a structure substantially similar to that in the temporal elongated slot 61. Having structures in both elongated slots 61, 62 can enhance holding force and may require greater manual force from the user to move the rear lens element 41 along a lateral path relative to the front lens element 31; however, in such embodiments, the structures in the slots 61, 62 must be aligned with each other. In some embodiments, one or both of the upper shoulder portions 51, 52 may include a structure 102 substantially similar to that in the lower elongated slots 61, 62.

[0076] Shoulders 51, 52, slots 61, 62, and guide pins 81, 82, 91, 92 serve as guiding elements to guide the rear lens element 41 to move laterally relative to the front lens element 31 across the observation direction z in the lateral direction x, while restricting the movement of the rear lens element 41 relative to the front lens element 31 to a low-tolerance lateral path. As mentioned above, the guide pins 81, 82 are sized to form a tight fit within the slots 51, 52, thereby preventing the rear lens element 41 from moving relative to the front lens element 31 in the y direction perpendicular to the x-axis and preventing the rear lens element 41 from yawing relative to the front lens element 31 in the x,y plane.

[0077] The dimensions of the temporal and nasal portions 6 and 7 of the frame 17 are designed such that the temporal and nasal edges 46 and 47 of the rear lens element 41 are obscured by the frame 12 regardless of its position, and are therefore "invisible" from the perspective of an observer looking directly at the user. Furthermore, the cooperating guide components, magnetic fasteners, and positioning mechanisms are all hidden behind the frame and cannot be seen by an observer. However, the outer edge of the rear lens element may still be visible when viewed from the side.

[0078] Although this application has been described and illustrated with reference to specific embodiments, those skilled in the art will understand that this application is applicable to many different variations not specifically described herein. Some possible variations will now be described, by way of example only.

[0079] Therefore, in some embodiments, the height of the rear lens element 41 between its upper and lower edges 44, 45 may be slightly greater than the height of the front lens element 31, such that the top and bottom edges 44, 45 of the rear lens element 41 both protrude beyond the corresponding edges 34, 35 of the front lens element 31. In an alternative embodiment, the engagement portion 78 may be located at the top edge 44 of the rear lens element 41. In a variant, instead of integrally molding the rear lens element 41 with the engagement portion 78, a small component providing enhanced friction may be attached to the bottom or top edges 45, 44 of the rear lens element 41. This can be achieved by bonding to an additional medium (e.g., transparent sandpaper), embedding a small ball bearing or other medium in the top or bottom edges 44, 45, or using a coating process (e.g., dip coating, spray coating), or by two-part injection molding (overmolding) of a high-friction elastic (e.g., TPU) material.

[0080] The positioning mechanism can be located on the upper part 4 of the frame edge portion 17. The adjustment mechanism can be located on the upper and lower parts of the frame edge portion. This enhances the holding strength of the rear lens element against lateral movement relative to the frame.

[0081] In the foregoing description, all integers or elements mentioned have known, obvious, or foreseeable equivalents, which are incorporated herein as if listed individually. Reference should be made to the claims that define the true scope of this application, which should be interpreted as covering any such equivalents. The reader should also understand that integers or features described herein as preferred, advantageous, convenient, etc., are optional and do not limit the scope of protection of the independent claims. Furthermore, it should be understood that while such optional integers or features may be beneficial in some embodiments of this application, they may not be required and therefore may not be present in other embodiments.

Claims

1. An adjustable focus eyeglasses device, comprising: At least one lens is mounted on a frame to support the lens in front of the user's eyes, thereby defining the direction of observation through the lens; The at least one of the lenses is a variable focal length lens of the following type, comprising two stacked lens elements having cooperating optical surfaces, the shape of which allows the focal length of the lens to be changed according to the relative lateral arrangement of the lens elements in a direction transverse to the observation direction. The lens elements are slidable relative to each other along a lateral path oriented laterally to the viewing direction to change the focal length of the lens. The lens further includes: The guide components on the lens element cooperate with each other, which restrict the relative lateral movement of the lens element within the lateral path; and magnetic fasteners for releasably securing the lens elements to each other, the magnetic fasteners comprising an elongated magnetic strip disposed on or fixedly connected to one of the lens elements; and a cooperating magnetic slider disposed on or fixedly connected to the other lens element. The magnetic slider and magnetic strip are configured and arranged such that, during the reciprocating relative lateral movement of the lens elements along the lateral path, the lens elements are magnetically secured to each other and allowed to be disassembled from each other in the observation direction.

2. The adjustable focal length eyeglasses device of claim 1, comprising a lens element positioning mechanism defining a plurality of discrete relative positions of a lens element along the lateral path, wherein the positioning mechanism is arranged to laterally restrict the lens element within discrete relative positions along the lateral path, wherein the lens provides a different focal length at each discrete relative position of the lens element.

3. The adjustable focus eyeglasses device according to claim 2, wherein the positioning mechanism comprises: A first positioning component associated with one of the lens elements, and a second positioning component associated with the other lens element. The first and second positioning components are arranged to mechanically engage when the lens elements are fastened together, the mechanical engagement causing the lens elements to occupy one of the discrete relative positions and remain in one of the discrete relative positions without the presence of external force applied by the user.

4. The adjustable focus eyeglasses device of claim 3, wherein the positioning mechanism is configured to hold the lens element in each discrete relative position until a threshold force acting to move the lens element along the lateral path is exceeded.

5. The adjustable focal length eyeglass device according to any one of claims 2 to 4, wherein the positioning mechanism defines five selectable discrete relative positions of the lens element along a lateral path.

6. The adjustable focus eyeglasses device according to any one of claims 2 to 5, wherein the magnetic fastener provides a biasing force to bias the first positioning member and the second positioning member into mechanical engagement.

7. The adjustable focus eyeglasses device according to any one of claims 2 to 6, wherein the positioning mechanism is a manual positioning mechanism that can be manually operated by the user of the eyeglasses device.

8. The adjustable focus eyeglasses device according to any one of the preceding claims, wherein the cooperating guide components comprise: A first guide member includes a guide pin; and a second guide member includes a slot configured to receive the guide pin such that the guide pin can slide within the slot, wherein the slot is configured to restrict movement of the guide pin in the lateral direction.

9. The adjustable focus eyeglasses device of claim 8 when referring to claim 3, wherein the first positioning member includes the guide pin, and the second positioning member includes the surface of another lens element within the slot, the surface having a series of grooves that engage with the guide pin. When the lens elements are fastened together, the guide pin can selectively engage with the groove to laterally restrict the lens elements to selected discrete relative positions.

10. The adjustable focus eyeglass device according to claim 8 or 9, wherein the series of grooves are disposed on the surface of another lens element oriented generally perpendicular to the observation direction, and the guide pin extends generally in the observation direction.

11. The adjustable focus eyeglasses device according to any one of claims 8 to 10, comprising a plurality of cooperative guide members spaced apart in the lateral direction.

12. The adjustable focus eyeglasses device according to any one of the preceding claims, wherein a first lens element is fixedly connected to the frame, and a second lens element is movable relative to the first lens element and the frame.

13. The adjustable focus eyeglasses device according to claim 12, wherein the first lens element is a front lens element and the second lens element is a rear lens element; when the eyeglasses device is actually worn by a user, the front lens element is the lens element farthest from the eye and the rear lens element is the lens element closest to the eye.

14. The adjustable focus eyeglasses device according to claim 12 or 13, wherein the magnetic strip is fixedly connected to the first lens element or the frame, and the magnetic slider is fixedly connected to the second lens element.

15. The adjustable focus eyeglasses device according to any one of the preceding claims, wherein the magnetic fastener is disposed behind the frame and stacked with the frame.

16. The adjustable focus eyeglasses device according to any one of the preceding claims, comprising at least two magnetic fasteners arranged at intervals in a direction orthogonal to both the lateral direction and the viewing direction.

17. The adjustable focal length eyeglasses device according to any one of the preceding claims, wherein the eyeglasses device is a pair of eyeglasses comprising a pair of variable focal length lenses.

18. A variable focal length lens, comprising: Two stacked lens elements having cooperative optical surfaces, the shape of which allows the focal length of the lens to be changed according to the relative lateral arrangement of the lens elements in a direction transverse to the observation direction. The lens elements can slide relative to each other along a lateral path oriented laterally to the observation direction to change the focal length of the lens. The lens further includes: The guide components on the lens element cooperate with each other, which restrict the relative lateral movement of the lens element within the lateral path; and Magnetic fasteners for releasably securing the lens elements to each other, the magnetic fasteners comprising an elongated magnetic strip disposed on or fixedly connected to one of the lens elements; and a cooperating magnetic slider disposed on or fixedly connected to the other lens element. The magnetic slider and magnetic strip are configured to: magnetically fasten the lens elements together during the reciprocating relative lateral movement of the lens elements along the lateral path, and allow the lens elements to be disassembled from each other in the observation direction.

19. The variable focal length lens of claim 18, comprising a lens element positioning mechanism defining a plurality of discrete relative positions of a lens element along the lateral path, wherein the positioning mechanism is arranged to laterally restrict the lens element within discrete relative positions along the lateral path, wherein the lens provides a different focal length at each discrete relative position of the lens element.

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