Electronic device having a tunable lens having two adjustable surfaces

Abstract

A lens module may include a first lens element, a lens-shaping structure coupled to the first lens element, and a plurality of actuators configured to adjust the position of the lens-shaping structure to adjust the first lens element. The lens module may also include a second lens element and a fluid-filled chamber between the first lens element and the second lens element. To allow dynamic adjustments of the second lens element without requiring additional actuators, the second lens element may be a semi-rigid lens element. When the actuators adjust the curvature of the first lens element, the gauge pressure applied to the second lens element changes. This causes a change in the curvature of the second lens element. Thus, the actuators can adjust the curvature of both the first and second lens elements even if none of the actuators are attached to the second lens element.

Description

Technology Field

[0001] This application claims priority to U.S. provisional patent application No. 63 / 174,840 filed on April 14, 2021, the entirety of which is incorporated herein by reference. Background Technology

[0002] The present invention generally relates to electronic devices, and more specifically to wearable electronic device systems.

[0003] Electronic devices are sometimes configured to be worn by users. For example, head-mounted devices are provided with a head-mounting structure that allows the devices to be worn on the user's head. Head-mounted devices may include optical systems having lenses. The lenses enable displays within the devices to present visual content to users.

[0004] Head-mounted devices typically include lenses having fixed shapes and properties. Without careful attention, it can be difficult to adjust these types of lenses to optimally present content to each user of the head-mounted device.

[0005] A head-mounted device may have a display that displays content for the user. Head-mounted support structures within the device support the display on the user's head.

[0006] A lens module within a head-mounted device may include a first transparent lens element, a lens-shaping structure coupled to the first transparent lens element, and a plurality of actuators configured to adjust the position of the lens-shaping structure to adjust the first transparent lens element. The lens module may also include a second transparent lens element and a fluid-filling chamber between the first transparent lens element and the second transparent lens element.

[0007] To allow dynamic adjustments of the second transparent lens element without requiring additional actuators within the lens module, the second transparent lens element may be a semi-rigid transparent lens element. When the actuators adjust the curvature of the first transparent lens element, the gauge pressure applied to the second transparent lens element changes. This causes a change in the curvature of the second transparent lens element. Thus, the actuators can adjust both the curvature of the first transparent lens element and the second transparent lens element even if none of the actuators are attached to the second transparent lens element.

[0008] The second transparent lens element may optionally be coupled to a biasing structure or a flexible seal to ensure that the second transparent lens element gradually changes its curvature when the curvature of the first transparent lens element is updated. In some arrangements, the second transparent lens element may be a bistable lens element that is convex in a first stable state and concave in a second stable state.

[0009] The lens module may also include a second fluid-filling chamber in addition to the first fluid-filling chamber. A channel between the first fluid-filling chamber and the second fluid-filling chamber may enable fluid to move between the first fluid-filling chamber and the second fluid-filling chamber. A valve within the channel may be opened or closed to enable fluid exchange. Actuators operating the first transparent lens element may be used to control the amount of fluid in the first fluid-filling chamber and the second fluid-filling chamber, respectively. Brief explanation of the drawing

[0010] FIG. 1 is a schematic diagram of an exemplary electronic device, such as a head-mounted display device according to one embodiment. FIG. 2 is a plan view of an exemplary head-mounted device according to one embodiment. FIGS. 3a and 3b are side cross-sectional views of an exemplary lens module including an elastomeric lens element and a rigid lens element according to one embodiment. FIG. 4 is a plan view of an exemplary lens shaping element including extensions for coupling to individual actuators according to one embodiment. FIGS. 5A and 5B are side cross-sectional views of an exemplary lens module including an elastomeric lens element and a semi-rigid lens element according to one embodiment. FIGS. 6a and 6b are side cross-sectional views of an exemplary lens module comprising a semi-rigid lens element and an elastomeric lens element coupled to a biasing structure according to one embodiment. FIGS. 7a and 7b are side cross-sectional views of an exemplary lens module comprising a semi-rigid lens element and an elastomeric lens element coupled to a flexible seal according to one embodiment. FIG. 8 is a side cross-sectional view of an exemplary lens module including first and second fluid-filling chambers and a valve for controlling flow between the first fluid-filling chamber and the second fluid-filling chamber, according to one embodiment. FIGS. 9a and 9b are side cross-sectional views of an exemplary lens module including an elastomeric lens element and a bistable semi-rigid lens element according to one embodiment. FIG. 10 is a graph of exemplary profiles for the radius of curvature of a lens element as a function of gauge pressure on the lens element, according to one embodiment. Specific details for implementing the invention

[0011] Electronic devices may include displays and other components for presenting content to users. Electronic devices may be wearable electronic devices. Wearable electronic devices, such as head-mounted devices, may have head-mounted support structures that enable the head-mounted device to be worn on a user's head.

[0012] A head-mounted device may include a display formed from one or more display panels (displays) for displaying visual content to a user. A lens system may be used to enable the user to focus on the display and view the visual content. The lens system may have a left lens module aligned with the user's left eye and a right lens module aligned with the user's right eye.

[0013] Lens modules within a head-mounted device may include adjustable lenses. For example, fluid-filled adjustable lenses may be used to adjust display content for specific observers.

[0014] A schematic diagram of an exemplary system having an electronic device equipped with a lens module is shown in FIG. 1. As shown in FIG. 1, the system (8) may include one or more electronic devices such as the electronic device (10). The electronic devices of the system (8) may include computers, cellular telephones, head-mounted devices, wristwatch devices, and other electronic devices. Configurations in which the electronic device (10) is a head-mounted device are sometimes described herein as examples.

[0015] As illustrated in FIG. 1, electronic devices such as electronic device (10) may have a control circuit section (12). The control circuit section (12) may include storage and processing circuit sections for controlling the operation of the device (10). The circuit section (12) may include storage such as a hard disk drive storage, non-volatile memory (e.g., electrically programmable read-only memory configured to form a solid-state drive), volatile memory (e.g., static or dynamic random access memory), etc. The processing circuit section within the control circuit section (12) may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors, power management units, audio chips, graphics processing units, application-specific integrated circuits, and other integrated circuits. Software code is stored in a repository within the circuit section (12) and executed on a processing circuit section within the circuit section (12) to implement control operations for the device (10) (e.g., data collection operations, operations involving processing three-dimensional facial image data, operations involving the coordination of components using control signals, etc.). The control circuit section (12) may include wired and wireless communication circuit sections. For example, the control circuit section (12) may include a radio frequency transceiver circuit section, such as a cellular telephone transceiver circuit section, a wireless local area network (WiFi®) transceiver circuit section, a millimeter wave transceiver circuit section, and / or other wireless communication circuit sections.

[0016] During operation, the communication circuit of the devices within the system (8) (e.g., the communication circuit of the control circuit (12) of the device (10)) may be used to support communication between electronic devices. For example, one electronic device may transmit video and / or audio data to another electronic device within the system (8). The electronic devices within the system (8) may communicate through one or more communication networks (e.g., the Internet, a local area network, etc.) using wired and / or wireless communication circuits. The communication circuit may be used to allow data to be received by the device (10) from external equipment (e.g., portable devices such as a tethered computer, a handheld device or a laptop computer, online computing equipment such as a remote server or other remote computing equipment, or other electrical equipment) and / or to provide data to the external equipment.

[0017] The device (10) may include input-output devices (22). The input-output devices (22) may be used to allow a user to provide user input to the device (10). The input-output devices (22) may also be used to collect information about the environment in which the device (10) is operating. Output components within the devices (22) may allow the device (10) to provide output to the user and may be used to communicate with external electrical equipment.

[0018] As illustrated in FIG. 1, the input-output devices (22) may include one or more displays, such as a display (14). In some configurations, the display (14) of the device (10) includes a left display panel and a right display panel that are aligned with the user's left and right eyes, respectively (sometimes referred to as the left portion and right portion of the display (14) and / or the left display and right display). In other configurations, the display (14) includes a single display panel that extends across both eyes.

[0019] The display (14) may be used to display images. Visual content displayed on the display (14) may be viewed by a user of the device (10). Displays within the device (10), such as the display (14), may be organic light-emitting diode displays or other displays based on arrays of light-emitting diodes, liquid crystal displays, LCoS (liquid-crystal-on-silicon) displays, projectors or displays based on projecting light beams onto a surface directly or indirectly through special optical devices (e.g., digital micromirror devices), electrophoretic displays, plasma displays, electrowetting displays, or any other suitable displays.

[0020] The display (14) can present display content for computer-generated reality (CGR), such as virtual reality content or mixed reality content. Configurations used for the display (14) to display virtual reality content to a user through lenses are sometimes described in this specification as examples.

[0021] The input-output circuit section (22) may include sensors (16). Sensors (16) are, for example, 3D sensors (e.g., 3D image sensors such as structured light sensors that emit beams of light and use 2D digital image sensors to collect image data for 3D images from light spots created when a target is illuminated by beams of light, binocular 3D image sensors that collect 3D images using two or more cameras in a binocular imaging array, 3D lidar (light detection and ranging) sensors, 3D radio frequency sensors, or other sensors that collect 3D image data), cameras (e.g., infrared and / or visible digital image sensors), eye tracking sensors (e.g., an eye tracking system based on an image sensor, and, if desired, a light source that emits one or more beams of light that are tracked using an image sensor after being reflected from the user's eyes), sensors such as touch sensors, buttons, force sensors, contact sensors based on switches, gas sensors, pressure sensors, moisture sensors, magnetic sensors, audio Sensors (microphones), ambient light sensors, microphones for collecting voice commands and other audio inputs, sensors configured to collect information regarding motion, position, and / or orientation (e.g., accelerometers, gyroscopes, compasses, and / or inertial measurement units including all of these sensors or a subset of one or two of these sensors), fingerprint sensors and other biometric sensors, optical position sensors (optical encoders), and / or other position sensors, e.g., linear position sensors, and / or other sensors may be included. Sensors (16) may include proximity sensors (e.g., capacitive proximity sensors, light-based (optical) proximity sensors, ultrasonic proximity sensors, and / or other proximity sensors).Proximity sensors can be used, for example, to detect relative positions between the user's nose and lens modules within the device (10).

[0022] User input and other information may be collected using sensors and other input devices within the input-output devices (22). If desired, the input-output devices (22) may include other devices (24), such as haptic output devices (e.g., vibration components), light-emitting diodes and other light sources, speakers such as ear speakers for generating audio output, and other electrical components. The device (10) may include circuits for receiving wireless power, circuits for wirelessly transmitting power to other devices, batteries and other energy storage devices (e.g., capacitors), joysticks, buttons, and / or other components.

[0023] The electronic device (10) may have housing structures (e.g., housing walls, straps, etc.) as illustrated by the exemplary support structures (26) of FIG. 1. In configurations where the electronic device (10) is a head-mounted device (e.g., a pair of glasses, goggles, a helmet, a hat, etc.), the support structures (26) may include head-mounted support structures (e.g., a helmet housing, head straps, temples in a pair of glasses, goggle housing structures, and / or other head-mounted structures). The head-mounted support structures may be configured to be worn on a user's head during operation of the device (10) and may support display(s) (14), sensors (16), other components (24), other input-output devices (22), and control circuitry (12).

[0024] FIG. 2 is a plan view of an electronic device (10) in an exemplary configuration in which the electronic device (10) is a head-mounted device. As illustrated in FIG. 2, the electronic device (10) may include support structures (e.g., see support structures (26) in FIG. 1) used to housing the components of the device (10) and to mount the device (10) on the user's head. These support structures may include, for example, structures forming housing walls and other structures for the main unit (26-2) (e.g., outer housing walls, lens module structures, etc.), and other supplementary support structures or straps such as structures (26-1) that help to hold the main unit (26-2) on the user's face.

[0025] The display (14) may include left and right display panels (e.g., left and right pixel arrays sometimes referred to as left and right displays or left and right display portions) that are respectively mounted within left and right display modules (70) corresponding to the user's left and right eyes, respectively. A display module corresponding to the user's left eye is illustrated in FIG. 2.

[0026] Each display module (70) comprises a display portion (14) and a corresponding lens module (72) (sometimes referred to as a lens stack-up (72), a lens (72), or an adjustable lens (72)). The lens (72) may comprise one or more lens elements arranged along a common axis. Each lens element may have any desired shape and may be formed of any desired material (e.g., having any desired refractive index). The lens elements may, in combination, have unique shapes and refractive indices that focus light from the display (14) in a desired manner. Each lens element of the lens module (72) may be formed of any desired material (e.g., glass, a polymer material such as polycarbonate or acrylic, a crystal such as sapphire, etc.).

[0027] The modules (70) may optionally be positioned individually with respect to the user's eyes and to some of the housing wall structures of the main unit (26-2) using a positioning circuit such as a positioner (58). The positioner (58) may include stepper motors, piezoelectric actuators, motors, linear electromagnetic actuators, and / or other electronic components for adjusting the position of the displays (14) and lens modules (72). The positioners (58) may be controlled by the control circuit (12) during the operation of the device (10). For example, the positioners (58) may be used to adjust the spacing between the modules (70) (and the corresponding lens-to-lens spacing between the left and right lenses of the modules (70)) to match the interpupillary distance (IPD) of the user's eyes.

[0028] In some cases, the distance between the lens module (72) and the display (14) is variable. For example, the distance between the lens module and the display can be adjusted to account for a specific user's vision. In other examples, the lens module may include an adjustable lens element. As an example, the curvature of the adjustable lens element can be adjusted in real time to compensate for the user's vision.

[0029] In some cases, the adjustable lens module may include a fluid-filled chamber. FIGS. 3a and FIGS. 3b are side cross-sectional views of an adjustable lens module (72) having a fluid-filled chamber. As illustrated, a fluid-filled chamber (82) containing fluid (92) (sometimes referred to as chamber (82) or fluid chamber (82)) is interposed between lens elements (84, 86).

[0030] The fluid (92) may be a liquid, gel, or gas having a predetermined refractive index (and accordingly may sometimes be referred to as the liquid (92), gel (92), or gas (92)). The fluid may sometimes be referred to as a refractive index matching oil, optical oil, optical fluid, refractive index matching material, refractive index matching liquid, etc. The lens elements (84, 86) may have the same refractive index or different refractive indices. The fluid (92) filling the chamber (82) between the lens elements (84, 86) may have a refractive index that is the same as the refractive index of the lens element (84) but different from the refractive index of the lens element (86), or may have a refractive index that is the same as the refractive index of the lens element (86) but different from the refractive index of the lens element (84), or may have a refractive index that is the same as the refractive index of the lens element (84) and the lens element (86), or may have a refractive index that is different from the refractive index of the lens element (84) and the lens element (86). The lens elements (84, 86) may be circular, elliptical, or have any other desired shape.

[0031] The amount of fluid (92) in the chamber (82) may have a constant volume or an adjustable volume. If the amount of fluid is adjustable, the lens module may also include a fluid reservoir and a fluid control component (e.g., a pump, a stepper motor, a piezoelectric actuator, a motor, a linear electromagnetic actuator, and / or other electronic component that applies force to the fluid in the fluid reservoir) for selectively transferring fluid between the fluid reservoir and the chamber.

[0032] The lens elements (84, 86) may be transparent lens elements formed from any desired material (e.g., glass, polymer materials such as polycarbonate or acrylic, crystals such as sapphire, etc.). Each of the lens elements (84, 86) may be elastomer, semi-rigid, or rigid. Elastomer lens elements may be formed from natural or synthetic polymers having a low Young's modulus for high flexibility. For example, the elastomer lens element (84) (sometimes referred to as an elastomer membrane) may be formed from a material having a Young's modulus of less than 1 GPa, less than 0.5 GPa, less than 0.1 GPa, etc.

[0033] Semi-rigid lens elements can be formed from a semi-rigid material that is rigid and solid but not inflexible. Semi-rigid lens elements can be formed from, for example, a thin layer of polymer or glass. Semi-rigid lens elements can be formed from materials having a Young's modulus greater than 1 GPa, greater than 2 GPa, greater than 3 GPa, greater than 10 GPa, greater than 25 GPa, etc. Semi-rigid lens elements can be formed from polycarbonate, polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), acrylic, glass, or any other desired material. The properties of the semi-rigid lens elements can result in the lens element becoming rigid along the first axis when the lens element is bent along a second axis perpendicular to the first axis. This is in contrast to an elastomer lens element that maintains flexibility along the first axis even when the lens element is bent along a second axis perpendicular to the first axis. The properties of semi-rigid lens elements can allow them to form cylindrical lenses having tunable lens magnification and tunable axes. Semi-rigid lens elements may be stiffer than elastomer lens elements but less stiff than rigid lens elements.

[0034] Rigid lens elements may be formed from glass, polymer materials such as polycarbonate or acrylic, crystals such as sapphire, etc. Generally, rigid lens elements may not deform when pressure is applied to the lens elements within the lens module. In other words, the shape and position of the rigid lens elements may be fixed. Each surface of the rigid lens element may be planar, concave (e.g., spherically or cylindrically concave), or convex (e.g., spherically or cylindrically convex). Rigid lens elements may be formed from materials having a Young's modulus greater than 25 GPa, greater than 30 GPa, greater than 40 GPa, greater than 50 GPa, etc.

[0035] In FIG. 3a and FIG. 3b (and subsequent drawings), the observer may be configured to view the lens module in the positive Z-direction. In other words, when the observer operates the device (10), the lens element (86) is interposed between the observer and the lens element (84). Alternatively, when the observer operates the device (10), the lens element (84) is interposed between the lens element (86) and the display (14).

[0036] In addition to the lens elements (84, 86) and the fluid-filling chamber (82), the lens module (72) also includes a lens shaping element (88). The lens shaping element (88) may be coupled to one or more actuators (90). For example, multiple actuators may be positioned around the circumference of the lens shaping element, or a single actuator may control the deflection of the lens shaping element at multiple points around the circumference of the lens shaping element. The lens shaping element (88) may also be coupled to the lens element (84). The actuators (90) may be moved to position the lens shaping element (88) (sometimes referred to as a lens shaper (88), a deformable lens shaper (88), a lens shaping structure (88), a lens shaping member (88), an annular member (88), a ring-shaped structure (88), etc.). The lens shaping element (88) sequentially manipulates the positioning / shape of the lens element (84). In this way, the curvature of the lens element (84) (and accordingly, the lens magnification of the lens module (72)) can be adjusted. An example in which actuators (90) and the lens shaping element (88) are used to change the curvature of the lens element (84) is illustrated in FIG. 3b. As illustrated, the lens shaping element (88) is moved in the direction (94) by the actuators (90). This results in the lens element (84) having a curvature in FIG. 3b (having a concave curvature) that is different from FIG. 3a (having a convex curvature).

[0037] FIG. 4 is a plan view of an exemplary lens-shaping element (88). As illustrated, the lens-shaping element (88) may have an annular or ring shape, and the lens-shaping element surrounds a central opening. The lens-shaping element may have any desired shape. For example, the lens-shaping element may have a circular, elliptical, or irregular shape. In the example of FIG. 4, the lens-shaping element has an irregular shape (e.g., an uneven radius around a ring shape). For example, a first distance (96) (e.g., minimum distance) from the center of the central opening to the edge of the lens-shaping element may be smaller than a second distance (98) (e.g., maximum distance) from the center of the central opening to the edge of the lens-shaping element. The distance (96, 98) may be less than 100 millimeters, less than 60 millimeters, less than 40 millimeters, less than 30 millimeters, greater than 10 millimeters, greater than 20 millimeters, 10 to 50 millimeters, etc.

[0038] The lens shaping element (88) has a plurality of tabs (88E) extending from the main part of the lens shaping element. The tabs (88E) (sometimes referred to as extensions (88E), actuator points (88E), etc.) can be coupled to individual actuators (or individual deflection-control parts of a single actuator). In one example, each actuator tab can protrude into a slot of the actuator (e.g., a tongue-and-groove arrangement). The slot can be optionally moved up and down (e.g., in the Z-direction) to control the position of the tab (88E) in the Z-direction. In other words, the actuator (90) is a linear actuator. These examples are merely exemplary. Generally, any desired type of actuator (e.g., tongue-and-groove actuator, actuator with hinge-style paddle, etc.) can be used.

[0039] In FIG. 4, a plurality of tabs (88E) (and corresponding actuators) can be distributed around the perimeter of a lens shaping element (88). The tabs (88E) can be distributed around the lens shaping element (88) in a uniform manner (e.g., at equal intervals between each pair of adjacent tabs (88E)) or in a non-uniform manner (e.g., at unequal intervals between at least two of adjacent tabs (88E).

[0040] Between each pair of adjacent tabs (88E), there is a lens shaper segment (88S). In the example of FIG. 4, there are eight tabs (88E) around the circumference of the lens shaper element (88). This example is merely illustrative. Generally, more tabs (and corresponding actuators) enable greater control over the shape of the lens element (e.g., lens element (84)) to which the lens shaper element (88) is coupled. Any desired number of tabs and actuators (e.g., 1, 2, 3, 4, more than 4, more than 6, more than 8, more than 10, more than 12, more than 20, less than 20, less than 10, 4 to 12, etc.) may be used depending on specific target shapes for the lens element, the target cost / complexity of the lens module, etc.

[0041] Generally, each actuator can act as a point force applying force in only one direction (e.g., parallel to the Z-axis). To prevent unintended application of torque or other force to the lens shaping element (88), the actuator slots may be larger than the extensions (88E). This provides space for the tab (88E) to rotate within the slot (preventing torque from being applied to the lens shaping element). Additionally, the extension (88E) may slide in and out of the slot to prevent unintended elongation of the lens shaping element.

[0042] The lens shaping element (88) may be an elastomer (e.g., a natural or synthetic polymer having a low Young's modulus for high flexibility, as discussed in more detail above) or a semi-rigid (e.g., formed from a semi-rigid material that is rigid and solid but not inflexible, as discussed in more detail above). The semi-rigid lens shaping element may be formed as a thin layer of, for example, a polymer, glass, metal, etc. Since the lens shaping element (88) is formed in a ring around the lens module, the lens shaping element (88) does not need to be transparent (and accordingly may be formed from an opaque material such as metal).

[0043] Returning to FIGS. 3a and 3b, the lens elements (86) and / or actuators (90) may be attached to a support structure (102) (sometimes referred to as the lens module support structure (102), lens housing (102), etc.). The support structure (102) may be formed in a ring around the lens module and may be formed of an opaque or transparent material. The support structure (102) may be rigid and thus may provide mechanical strength to the lens module (72). The chamber (82) may be defined by the lens elements (84, 86), the support structure (102), and / or flexible bellows (104). The flexible bellows (104) may expand and contract to accommodate the chamber operated by the lens shaper (88) and the actuators (90).

[0044] In the examples of FIGS. 3a and 3b, the lens element (84) is an elastomer lens element, and the lens element (86) is a rigid lens element (e.g., having greater rigidity than the lens element (84)). In FIG. 3a, the lens element (84) is manipulated to have a convex shape by the lens shaping element (88). With this type of arrangement, a positive gauge pressure (e.g., a negative Z-direction force) can be applied to the rigid lens element (86). In FIG. 3b, the lens element (84) is manipulated to have a concave shape by the lens shaping element (88). With this type of arrangement, a negative gauge pressure (e.g., a positive Z-direction force) can be applied to the rigid lens element (86). However, in both FIG. 3a and FIG. 3b, since the lens element (86) is a rigid lens element, the shape of the lens element (86) remains constant regardless of whether a positive gauge pressure or a negative gauge pressure is applied. As shown in FIG. 3a and FIG. 3b, the rigid lens element (86) can maintain the same curvature regardless of how the actuators (90) position the lens shaper (88).

[0045] In some cases, it may be desirable for the lens element (86) to also have an adjustable shape. Additional actuators may be included in the lens module to directly manipulate the shape of the lens element (86) (similar to the lens element (84)). However, to minimize the cost, complexity, and weight of the device, it may be desirable to avoid including dedicated actuators for the lens element (86). To provide an adjustable lens element (86) without including additional actuators, the lens element (86) may be a semi-rigid lens element. An arrangement of this type is illustrated in FIGS. 5a and 5b.

[0046] FIGS. 5a and 5b are side cross-sectional views of lens modules having an elastomeric lens element (84) and a semi-rigid lens element (86). The overall structure of the lens module is similar to the structure described in relation to FIGS. 3a and 3b, and descriptions of these overlapping parts will not be repeated for clarity. The elastomeric lens element (84) and the semi-rigid lens element (86) may be formed of the same material or different materials.

[0047] FIG. 5a illustrates a lens module in a position where the lens element (84) is manipulated to have a convex shape by a lens shaping element (88). With this type of arrangement, a positive gauge pressure (e.g., a negative Z-direction force) may be applied to the semi-rigid lens element (86). This causes the semi-rigid lens element (86) to take on a relatively flat shape with a minimum curvature (as shown in FIG. 5a). The radius of curvature of the lens element (86) in FIG. 5a may be relatively large (when the lens element (84) has a convex curvature). Alternatively, the lens element (86) in FIG. 5a may be flat when the lens element (84) has a convex curvature.

[0048] Conversely, FIG. 5b illustrates a lens module in which the lens element (84) is manipulated to have a concave shape by the lens shaping element (88). In this type of arrangement, a negative gauge pressure (e.g., a positive Z-direction force) may be applied to the semi-rigid lens element (86). This causes the semi-rigid lens element (86) to have a concave curvature with a smaller radius of curvature than in FIG. 5a. The radius of curvature of the lens element (86) may change sign and / or vary by more than 10%, more than 20%, more than 50%, more than 100%, more than 200%, etc. when comparing the arrangement of FIG. 5b with the arrangement of FIG. 5a.

[0049] Generally, it is desirable for the semi-rigid lens element (86) to have less concave curvature when the lens element (84) has greater convex curvature, and it may be desirable for the semi-rigid lens element (86) to have greater concave curvature when the lens element (84) has greater concave curvature. This type of arrangement can help mimic lens structures of prescription eyeglasses, for example. The lens module of FIGS. 5a and 5b achieves this relationship (where the concave curvature of the lens element (86) decreases as the convex curvature increases) without requiring additional actuators to directly control the shape of the lens element (86). In other words, no actuators within the lens module are attached to the lens element (86). However, pressure applied to the lens element (86) as a result of the lens element (84) being manipulated (by the actuators (90)) causes the lens element (86) to take on the desired curvature. The curvature of the lens element (86) can change gradually as the actuators (90) change the curvature of the lens element (84) (since the gauge pressure on the lens element (86) also changes gradually and the shape of the lens element (86) responds to the gauge pressure).

[0050] In FIGS. 5a and 5b, the elastomeric lens element (84) may have a Young's modulus of less than 1 GPa, less than 0.5 GPa, less than 0.1 GPa, etc. Meanwhile, the semi-rigid lens elements (86) may be formed from a semi-rigid material that is rigid and solid but not inflexible. The semi-rigid lens element (86) may be formed from, for example, a thin layer of polymer or glass. The semi-rigid lens element (86) may be formed from a material having a Young's modulus greater than 1 GPa, greater than 2 GPa, greater than 3 GPa, greater than 10 GPa, greater than 25 GPa, etc. Thus, the Young's modulus of the lens element (86) may be greater than the Young's modulus of the lens element (84).

[0051] In the aforementioned example (where the semi-rigid lens element (86) has a greater Young's modulus than the elastomeric lens element (84)), the elastomeric lens element (84) and the semi-rigid lens element (86) may be formed from different materials. This example is merely illustrative. In other possible examples, the elastomeric lens element (84) and the semi-rigid lens element (86) may be formed from the same materials but may have different thicknesses. For example, the semi-rigid lens element (86) may have a thicker thickness than the lens element (84). The semi-rigid lens element may have a thickness greater than 1.5 times the thickness of the lens element (84), greater than 2 times the thickness of the lens element (84), greater than 3 times the thickness of the lens element (84), greater than 5 times the thickness of the lens element (84), greater than 10 times the thickness of the lens element (84), greater than 50 times the thickness of the lens element (84), 1.5 to 10 times the thickness of the lens element (84), less than 20 times the thickness of the lens element (84), etc. Generally, the lens element (86) may have a greater thickness and / or Young's modulus than the lens element (84).

[0052] FIGS. 6a and 6b are side cross-sectional views of a lens module having an elastomeric lens element (84) and a dynamically adjustable semi-rigid lens element (86). The overall structure of the lens module is similar to the structure described in relation to FIGS. 5a and 5b, and descriptions of these overlapping parts will not be repeated for clarity.

[0053] To ensure that the lens element (86) gradually changes its shape (curvature) as a function of changing gauge pressure, the lens module may also include a biasing structure (106). The biasing structure (106) may extend from a ring around the lens module and may apply a bias force to the lens element (86) (which has a disc-shaped form). The biasing structure (106) may bias the edges of the lens element (86) toward the center of the lens element (86). For example, on the left side of FIG. 6b, the biasing structure (106) biases the semi-rigid lens element (86) in the positive X-direction (toward the center of the lens element (86). On the right side of FIG. 6b, the biasing structure (106) biases the semi-rigid lens element (86) in the negative X-direction (toward the center of the lens element (86). The biasing structure (106) may be formed as a spring, a flexible bellows structure, or any other desired structure that applies a bias force to the edges of the lens element (86). The biasing structure (106) may be formed as a continuous ring around the lens element (86), or may include a plurality of discrete biasing structures distributed around the periphery of the lens element that each apply a point force to the lens element (86) at a given position.

[0054] FIG. 6a illustrates a lens module in a position where the lens element (84) is manipulated to have a convex shape by a lens shaping element (88) (and actuators (90)). In this type of arrangement, a positive gauge pressure (e.g., a negative Z-direction force) may be applied to the semi-rigid lens element (86). This causes the edges of the semi-rigid lens element (86) to be pushed outward against the biasing structure (106). The semi-rigid lens element (86) takes on a relatively flat shape with a minimum curvature (as shown in FIG. 6a). The radius of curvature of the lens element (86) in FIG. 6a may be relatively large (when the lens element (84) has a convex curvature). Alternatively, the lens element (86) in FIG. 6a may be flat when the lens element (84) has a convex curvature.

[0055] Conversely, FIG. 6b illustrates a lens module in which the lens element (84) is manipulated to have a concave shape by the lens shaping element (88). In this type of arrangement, a negative gauge pressure (e.g., a positive Z-direction force) may be applied to the semi-rigid lens element (86). This causes the semi-rigid lens element (86) to have a concave curvature with a smaller radius of curvature than in FIG. 6a. The biasing structure (106) helps push the edges of the lens elements toward the center of the lens element to provide the lens element (86) with the desired concave curvature. Thus, the biasing structure (106) (sometimes referred to as a spring (106), a flexible bellows structure (106), a flexible sealing structure (106), etc.) helps the lens element (86) gradually change its shape (curvature) as a function of the changing gauge pressure. With the help of a biasing structure, the lens element (86) gradually changes its shape from a flat or high radius of curvature shape (as in FIG. 6a) to a concave shape (as in FIG. 6b) when the actuators (90) gradually change the shape of the lens element (84) from convex (as in FIG. 6a) to concave (as in FIG. 6b).

[0056] The radius of curvature of the lens element (86) can change its sign and / or, when comparing the arrangement of FIG. 6b with the arrangement of FIG. 6a, it can change by more than 10%, more than 20%, more than 50%, more than 100%, more than 200%, etc.

[0057] The biasing structure (106) may be attached to the edge of the lens element (86) using an adhesive or secured to the edge of the lens element (86) using another desired attachment mechanism (e.g., mechanical interlocking). As another possible example, the biasing structure (106) may be formed integrally with the lens element (86) (e.g., may be formed from the same material as the lens element (86) and / or may be molded with the lens element (86) in a single step).

[0058] FIGS. 7a and 7b are side cross-sectional views of a lens module having an elastomeric lens element (84) and a dynamically adjustable semi-rigid lens element (86) having a flexible seal. The overall structure of the lens module is similar to the structure described in relation to FIGS. 5a and 5b, and descriptions of these overlapping parts will not be repeated for clarity.

[0059] To help ensure that the lens element (86) gradually changes its shape (curvature) as a function of changing gauge pressure, the lens module may also include a flexible seal (108). The flexible seal (108) may extend from a ring around the lens module and may be interposed between the lens element (86) and the support structure (102). The flexible seal (108) may form an airtight seal between the lens element (86) and the support structure (102) to ensure that the fluid (92) does not leak from the seal into or out of the chamber (82).

[0060] A flexible seal can apply a bias force to a lens element (86) (having a disc-shape) (similar to a biasing structure (106)). The flexible seal (108) can bias the edges of the lens element (86) toward the center of the lens element. For example, on the left side of FIG. 7b, the flexible seal (108) biases the semi-rigid lens element (86) in the positive X-direction (toward the center of the lens element (86). On the right side of FIG. 7b, the flexible seal (108) biases the semi-rigid lens element (86) in the negative X-direction (toward the center of the lens element (86).

[0061] The flexible seal (108) may be formed from the same material as the lens element (86). In this type of arrangement, the flexible seal (108) may be thinner than the lens element (86). The flexible seal (108) may also be formed from a different material from the lens element (86) (e.g., a more elastic material having a lower Young's modulus). The flexible seal (108) (sometimes referred to as a biasing structure (108), a flexible lip (108), a flexible wall (108), etc.) may be formed as a continuous ring around the lens element (86).

[0062] FIG. 7a illustrates a lens module in a position where the lens element (84) is manipulated to have a convex shape by a lens shaping element (88). In this type of arrangement, a positive gauge pressure (e.g., a negative Z-direction force) may be applied to the semi-rigid lens element (86). This causes the edges of the semi-rigid lens element (86) to be pushed outward against the flexible seal (108). The flexible seal (108) accommodates the lateral expansion (e.g., in the X-direction) of the lens element (86) in this position. The semi-rigid lens element (86) takes on a relatively flat shape with a minimum curvature (as shown in FIG. 7a). (If the lens element (84) has a convex curvature) the radius of curvature of the lens element (86) in FIG. 6a may be relatively large. Alternatively, the lens element (86) of FIG. 7a may be flat when the lens element (84) has a convex curvature.

[0063] Conversely, FIG. 7b illustrates a lens module in which the lens element (84) is manipulated to have a concave shape by the lens shaping element (88). In this type of arrangement, a negative gauge pressure (e.g., a positive Z-direction force) may be applied to the semi-rigid lens element (86). This causes the semi-rigid lens element (86) to have a concave curvature with a smaller radius of curvature than in FIG. 7a. The flexible seal (108) helps push the edges of the lens elements toward the center of the lens element to provide the lens element (86) with the desired concave curvature. Thus, the flexible seal (108) helps the lens element (86) gradually change its shape (curvature) as a function of the changing gauge pressure. With the help of a flexible seal, the lens element (86) gradually changes its shape from a flat or high radius of curvature shape (as in FIG. 7a) to a concave shape (as in FIG. 7b) when the actuators (90) gradually change the shape of the lens element (84) from convex (as in FIG. 7a) to concave (as in FIG. 7b).

[0064] The radius of curvature of the lens element (86) can change its sign and / or, when comparing the arrangement of FIG. 7b with the arrangement of FIG. 7a, it can change by more than 10%, more than 20%, more than 50%, more than 100%, more than 200%, etc.

[0065] The flexible seal (108) may be attached to the edge of the lens element (86) using an adhesive or secured to the edge of the lens element (86) using another desired attachment mechanism (e.g., mechanical interlocking). As another possible example, the flexible seal (108) may be formed integrally with the lens element (86) (e.g., may be formed from the same material as the lens element (86) and / or may be molded with the lens element (86) in a single step).

[0066] FIG. 8 is a side cross-sectional view of a lens module having first and second elastomer lens elements and first and second chambers. The lens module (72) of FIG. 8 includes a first fluid-filling chamber (82-1) and a second fluid-filling chamber (82-2). Both the first and second fluid-filling chambers (82-1, 82-2) are filled with fluid (92) (as previously described). The fluid-filling chamber (82-1) (sometimes referred to as chamber (82-1) or fluid chamber (82-1)) is interposed between the lens elements (84-1, 86) (and is partially defined by them). The fluid-filling chamber (82-2) (sometimes referred to as chamber (82-2) or fluid chamber (82-2)) is interposed between the lens elements (84-2 and 86) (and is partially defined by them).

[0067] In FIG. 8, the lens elements (84-1, 84-2) are elastomeric lens elements, whereas the lens element (86) is a rigid lens element (having higher rigidity than the lens elements (84-1, 84-2)). The lens element (84-1) may be attached to a lens shaper (88) (as discussed in previous drawings) that controls the curvature of the lens element (84-1). The lens module (72) of FIG. 8 also includes a support structure (102), a flexible bellows (104), and one or more actuators, as already illustrated and discussed above.

[0068] To enable control of the shape of the elastomeric lens element (84-2) without adding additional actuators, a valve (110) may be interposed in a channel (112) between chambers (82-1, 82-2). The channel (112) may allow fluid to flow between chambers (82-1, 82-2) when the valve (110) is opened. When the valve (110) is closed, the volume of fluid within chambers (82-1, 82-2) may be maintained in a fixed state. A control circuit (e.g., the control circuit (12) of FIG. 1) may control the valve (112) using a control signal line (114).

[0069] As illustrated in FIG. 8, the channel (112) between the chambers (82-1, 82-2) may include an opening in a flexible bellows structure (104) (to allow access to chamber (82-1)) and / or an opening in a support structure (102) (to allow access to chamber (82-2). These examples are merely exemplary. Generally, the channel (112) and the valve (110) may be located at any desired location to enable fluid exchange between the chambers (82-1, 82-2).

[0070] In addition to controlling the curvature of the lens element (84-1), the lens shaper (88) (and corresponding actuators) can effectively serve as a pump to control the exchange of fluid between the chambers (82-1, 82-2). The control circuit within the device can control the actuators to move the lens shaper (88) in the negative Z-direction while opening the valve (110). In this state, the lens element (84-1) is provided with a convex curvature, and a positive gauge pressure (e.g., a negative Z-direction force) is applied to the rigid lens element (86). This positive gauge pressure does not deform the rigid lens element (86) (it maintains its curvature). However, the pressure from the lens shaper / actuators forces the fluid (92) from chamber (82-1) into chamber (82-2) (through the channel (112)). The increased volume within the chamber (82-2) pushes the elastomer lens element (84-2) in the negative Z-direction, thereby reducing the curvature of the lens element (84-2). Once the desired lens shape is achieved, the control circuit can close the valve (110).

[0071] The control circuit within the device can control the actuators to move the lens shaper (88) in the positive Z-direction while opening the valve (110). In this state, the lens element (84-1) is provided with a concave curvature (e.g., as in FIG. 7b), and a negative gauge pressure is applied to the rigid lens element (86). This negative gauge pressure does not deform the rigid lens element (86) (it maintains its curvature). However, the negative pressure from the lens shaper / actuators draws fluid (92) from the chamber (82-2) into the chamber (82-1). The reduced volume within the chamber (82-2) allows the elastomer lens element (84-2) to move in the positive Z-direction, thereby increasing the curvature of the lens element (84-2). Once the desired lens shape is achieved, the control circuit can close the valve (110). In this way, the lens shapers / actuators and the valve (110) can be used to control both of the curvatures of the lens elements (84-1, 84-2).

[0072] The radius of curvature of the lens element (84-2) can change its sign and / or change by more than 10%, more than 20%, more than 50%, more than 100%, more than 200%, etc. in response to the control of the lens shaper (88) of FIG. 8.

[0073] FIGS. 9a and 9b are side cross-sectional views of a lens module having an elastomeric lens element (84) and a bistable semi-rigid lens element (86). The overall structure of the lens module is similar to the structure described in relation to FIGS. 5a and 5b, and descriptions of these overlapping parts will not be repeated for clarity. The elastomeric lens element (84) and the semi-rigid lens element (86) may be formed of the same material or different materials.

[0074] FIG. 9a illustrates a lens module in a position where the lens element (84) is manipulated to have a concave shape by the lens shaping element (88). In this type of arrangement, a negative gauge pressure (e.g., a positive Z-direction force) may be applied to the semi-rigid lens element (86). This causes the semi-rigid lens element (86) to have a concave curvature with a relatively small radius of curvature.

[0075] In FIGS. 9a and 9b, the semi-rigid lens element (86) may be subjected to pre-stress when integrated into the lens module (72). In other words, to fit into the lens module, the semi-rigid lens element (86) may be laterally compressed (e.g., by pressure applied to the edges of the lens element toward the center of the lens element). A support structure (102) may apply this pre-stress, for example. Due to the pre-stress applied to the semi-rigid lens element, the semi-rigid lens element may have two stable states. Thus, the semi-rigid lens element may sometimes be referred to as a bistable semi-rigid lens element. Instead of gradually changing from a first curvature to a second curvature (e.g., as in FIGS. 5a and 5b), as the lens shaper (88) moves in the negative Z-direction, the curvature of the lens element (86) may be maintained as shown in FIG. 9a. In other words, the curvature of the lens element (86) is maintained in a fixed state in the first stable state (as in FIG. 9a) while varying the gauge pressure until it reaches a gauge pressure that causes the lens element to flip to its second stable state (as shown in FIG. 9b).

[0076] In the second stable state, the lens element (84) is manipulated to have a convex shape by the lens shaping element (88). With this type of arrangement, a positive gauge pressure (e.g., a negative Z-direction force) can be applied to the semi-rigid lens element (86). This causes the semi-rigid lens element (86) to have a convex curvature.

[0077] Accordingly, the prestressed lens element (86) causes the lens element (86) to have a convex curvature if the lens element (84) also has a convex curvature, and to have a concave curvature if the lens element (84) also has a concave curvature. These examples are merely exemplary. In general, any desired relationship between the curvatures of the lenses (84, 86) may be used. However, in this arrangement, the curvature of the lens element (86) may have two different stable states (due to the prestress applied to the edges of the lens element (86).

[0078] In other possible arrangements, the lens element may have more than two stable states and may switch between three or more stable states depending on the applied gauge pressure. However, the curvature does not change between three or more stable states.

[0079] The radius of curvature of the lens element (86) can change its sign and / or, when comparing the arrangement of FIG. 9b with the arrangement of FIG. 9a, it can change by more than 10%, more than 20%, more than 50%, more than 100%, more than 200%, etc.

[0080] FIG. 10 is a graph of various radius of curvature profiles for a lens element as a function of gauge pressure on the lens element. It should be noted that gauge pressure represents the curvature of the elastomeric lens element (84) within the lens module. For example, consider FIGS. 5a and 5b. When the lens element (84) is controlled to have a concave curvature, the associated gauge pressure for the lens element (86) is low (e.g., negative gauge pressure (P1)). When the lens element (84) is controlled to have a convex curvature, the associated gauge pressure for the lens element (86) is high (e.g., positive gauge pressure (P2)).

[0081] Profile (202) illustrates the radius of curvature of the rigid lens element (86) of FIGS. 3a and FIGS. 3b. As illustrated, since the lens element is rigid, the radius of curvature of the lens element remains constant from negative gauge pressure (P1) to positive gauge pressure (P2).

[0082] Profile (204) illustrates an exemplary profile for the radius of curvature of the semi-rigid lens element (86) of FIGS. 5 through 7 (or lens element (84-2) of FIG. 8). As illustrated, the radius of curvature of the lens element gradually increases (e.g., becomes less curved) as it moves from a negative gauge pressure (P1) to a positive gauge pressure (P2). In this way, the control circuit within the device can control the lens shaper (88) to manipulate the curvature of the lens element (84), which causes changes in the gauge pressure for the lens element (86), which causes changes in the curvature of the lens element (86) according to the profile (204) as illustrated. Thus, the curvature of the lens element (86) is dynamically updated in parallel with updating the curvature of the lens element (84). The control circuit within the device can control the lens elements to have curvatures at P1 and P2 of FIG. 10 or any intermediate gauge pressure / curvature.

[0083] Profile (206) illustrates an exemplary profile of the radius of curvature of the bistable semi-rigid lens element (86) of FIGS. 9a and 9b. As illustrated, the radius of curvature of the lens element remains constant in the first stable state as it moves from a negative gauge pressure (P1) to a positive gauge pressure (P2). At some intermediate pressure, the lens element (86) may switch from the first stable state to a second stable state. Thus, the curvature of the lens element will undergo a step change to a different curvature (e.g., the convex curvature of FIG. 9b). Subsequently, when the gauge pressure completes moving to a positive gauge pressure (P2), the radius of curvature of the lens element remains constant in the second stable state.

[0084] The shapes of the profiles (204 and 206) are merely exemplary. In general, any desired profile shapes may be used (e.g., profile (204) may be non-linear).

[0085] According to one embodiment, a system is provided comprising: a head-mounted support structure; a display emitting light; and a lens module supported by the head-mounted support structure for receiving light from the display, wherein the lens module comprises: a first transparent lens element and a second transparent lens element defining a chamber—the first transparent lens element being an elastomer lens element and the second transparent lens element being a semi-rigid lens element—; a fluid within the chamber between the first transparent lens element and the second transparent lens element; and a plurality of actuators configured to adjust a first curvature of the first transparent lens element, wherein adjusting the first curvature of the first transparent lens element also causes a change in the second curvature of the second transparent lens element.

[0086] According to another embodiment, a change in the second curvature of the second transparent lens element includes a change in the radius of curvature of the second transparent lens element of more than 20%.

[0087] According to another embodiment, the first transparent lens element is thinner than the second transparent lens element.

[0088] According to another embodiment, the first transparent lens element has a lower Young's modulus than the second transparent lens element.

[0089] According to another embodiment, the lens module includes a lens-shaping structure attached between a plurality of actuators and a first transparent lens element.

[0090] According to another embodiment, the lens-shaped structure has a plurality of extensions.

[0091] According to another embodiment, each of the plurality of extensions is coupled to an individual actuator of the plurality of actuators.

[0092] According to another embodiment, the lens-shaped structure extends from a ring around the central opening, and the first transparent lens element overlaps with the central opening.

[0093] According to another embodiment, the second transparent lens element is a bistable lens element having a first stable state and a second stable state, and the second curvature is concave in the first state and convex in the second state.

[0094] According to another embodiment, adjusting the first curvature from concave to convex causes the second transparent lens element to switch from a first stable state to a second stable state.

[0095] According to another embodiment, gradually adjusting the first curvature from concave to convex causes the radius of curvature of the second curvature to gradually increase.

[0096] According to another embodiment, the lens module includes a biasing structure that applies force to the edge of the second transparent lens element toward the center of the second transparent lens element.

[0097] According to another embodiment, the lens module includes a support structure, and the biasing structure forms a seal between the second transparent lens element and the support structure.

[0098] According to another embodiment, a plurality of actuators are formed on a support structure.

[0099] According to one embodiment, a system is provided comprising: a head-mounted support structure; a display emitting light; and a lens module supported by the head-mounted support structure for receiving light from the display, wherein the lens module comprises: a first transparent lens element and a second transparent lens element defining a chamber—the first transparent lens element being an elastomer lens element and the second transparent lens element being a semi-rigid lens element—; a fluid in the chamber between the first transparent lens element and the second transparent lens element; and actuators attached to the first transparent lens element configured to dynamically adjust the curvature of both the first transparent lens element and the second transparent lens element, wherein no actuators are attached to the second transparent lens element.

[0100] According to another embodiment, the second transparent lens element has higher rigidity than the first transparent lens element.

[0101] According to another embodiment, the lens module includes a lens-shaping structure attached between actuators and a first transparent lens element.

[0102] According to another embodiment, the first transparent lens element is thinner than the second transparent lens element.

[0103] According to another embodiment, dynamically adjusting the curvature of both the first transparent lens element and the second transparent lens element includes adjusting the radius of curvature of the second transparent lens element by more than 20%.

[0104] According to one embodiment, a system is provided comprising: a head-mounted support structure; a display emitting light; and a lens module supported by the head-mounted support structure for receiving light from the display, wherein the lens module comprises: a rigid lens element; a first transparent lens element having a lower rigidity than the rigid lens element, wherein the first transparent lens element and the rigid lens element define a first fluid-filling chamber; a second transparent lens element having a lower rigidity than the rigid lens element, wherein the second transparent lens element and the rigid lens element define a second fluid-filling chamber, wherein the first transparent lens element is an elastomer lens element and the second transparent lens element is a semi-rigid lens element; a channel between the first fluid-filling chamber and the second fluid-filling chamber; a valve in the channel configured to be open to allow flow through the channel between the first fluid-filling chamber and the second fluid-filling chamber; and a plurality of actuators configured to move the first transparent lens element and control the flow between the first fluid-filling chamber and the second fluid-filling chamber while the valve is open.

[0105] According to another embodiment, the lens module includes a ring-shaped structure coupled to a first transparent lens element, and a plurality of actuators are configured to adjust the ring-shaped structure to move the first transparent lens element.

[0106] The foregoing is merely illustrative, and various modifications may be made to the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Claims

Claim 1 A wearable electronic device comprising: a head-mounted support structure; a display emitting light; and a lens module supported by the head-mounted support structure, which receives the light from the display, wherein the lens module comprises: a first transparent lens element and a second transparent lens element defining a chamber - wherein the first transparent lens element is an elastomer lens element and the second transparent lens element is a semi-rigid lens element -; a fluid within the chamber between the first transparent lens element and the second transparent lens element; and a plurality of actuators configured to adjust a first curvature of the first transparent lens element, wherein adjusting the first curvature of the first transparent lens element also causes a change in the second curvature of the second transparent lens element, and the change in the second curvature of the second transparent lens element includes a change in the radius of curvature of the second transparent lens element of more than 20%. Claim 2 delete Claim 3 A wearable electronic device according to claim 1, wherein the first transparent lens element is thinner than the second transparent lens element. Claim 4 A wearable electronic device according to claim 1, wherein the first transparent lens element has a lower Young's modulus than the second transparent lens element. Claim 5 A wearable electronic device according to claim 1, wherein the lens module further comprises a lens-shaping structure attached between the plurality of actuators and the first transparent lens element. Claim 6 In claim 5, the lens-shaped structure is a wearable electronic device having a plurality of extensions. Claim 7 A wearable electronic device according to claim 6, wherein each of the plurality of extensions is coupled to an individual actuator of the plurality of actuators. Claim 8 A wearable electronic device according to claim 5, wherein the lens-shaped structure extends from a ring around a central opening, and the first transparent lens element overlaps with the central opening. Claim 9 A wearable electronic device according to claim 1, wherein the second transparent lens element is a bistable lens element having a first stable state and a second stable state, and the second curvature is concave in the first stable state and convex in the second stable state. Claim 10 A wearable electronic device according to claim 9, wherein adjusting the first curvature from concave to convex causes the second transparent lens element to switch from the first stable state to the second stable state. Claim 11 A wearable electronic device according to claim 1, wherein gradually adjusting the first curvature from concave to convex causes the radius of curvature of the second curvature to gradually increase. Claim 12 A wearable electronic device according to claim 1, wherein the lens module further comprises a biasing structure that applies force to the edge of the second transparent lens element toward the center of the second transparent lens element. Claim 13 A wearable electronic device according to claim 12, wherein the lens module further comprises a support structure, and the biasing structure forms a seal between a second transparent lens element and the support structure. Claim 14 In claim 13, the plurality of actuators are formed on the support structure, a wearable electronic device. Claim 15 A wearable electronic device comprising: a head-mounted support structure; a display emitting light; and a lens module supported by the head-mounted support structure, which receives the light from the display, wherein the lens module comprises: a first transparent lens element and a second transparent lens element defining a chamber - wherein the first transparent lens element is an elastomer lens element and the second transparent lens element is a semi-rigid lens element -; a fluid within the chamber between the first transparent lens element and the second transparent lens element; and actuators attached to the first transparent lens element configured to dynamically adjust the curvature of both the first transparent lens element and the second transparent lens element, wherein dynamically adjusting the curvature of both the first transparent lens element and the second transparent lens element includes adjusting the radius of curvature of the second transparent lens element by more than 20%, and wherein no actuators are attached to the second transparent lens element. Claim 16 A wearable electronic device according to claim 15, wherein the second transparent lens element has higher rigidity than the first transparent lens element. Claim 17 A wearable electronic device according to claim 15, wherein the lens module further comprises a lens-shaping structure attached between the actuators and the first transparent lens element. Claim 18 A wearable electronic device according to claim 15, wherein the first transparent lens element is thinner than the second transparent lens element. Claim 19 delete Claim 20 A wearable electronic device comprising: a head-mounted support structure; a display emitting light; and a lens module supported by the head-mounted support structure, receiving light from the display, wherein the lens module comprises: a rigid lens element; a first transparent lens element having a lower rigidity than the rigid lens element - the first transparent lens element and the rigid lens element define a first fluid-filling chamber -; a second transparent lens element having a lower rigidity than the rigid lens element - the second transparent lens element and the rigid lens element define a second fluid-filling chamber, wherein the first transparent lens element is an elastomer lens element and the second transparent lens element is a semi-rigid lens element -; a channel between the first fluid-filling chamber and the second fluid-filling chamber; and a valve in the channel configured to be open to allow flow through the channel between the first fluid-filling chamber and the second fluid-filling chamber. A wearable electronic device comprising a plurality of actuators configured to move the first transparent lens element and control the flow between the first fluid-filling chamber and the second fluid-filling chamber while the valve is open. Claim 21 A wearable electronic device according to claim 20, wherein the lens module further comprises a ring-shaped structure coupled to the first transparent lens element, and the plurality of actuators are configured to adjust the ring-shaped structure to move the first transparent lens element.

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