Adjustable cylindrical lens and head-mounted display including it

Abstract

An adjustable lens is provided that can be integrated into the eyepieces of a head-mounted display, particularly a virtual reality head-mounted display, for correcting asymmetric vision. The system includes three optical elements arranged along an optical axis, each having a different cylinder axis and a variable cylinder power. Collectively, the three elements form a composite optical element with an overall spherical power (SPH), cylinder power (CYL), and cylinder axis (Axis) that can be varied according to a prescription (Rx).

Description

[Technical Field]

[0001] (Claiming priority) This application claims priority to U.S. Patent Application No. 63 / 062,746, filed on 7 August 2020, which is incorporated herein by reference in its entirety by reference under Section 119(e) of the U.S. Patent Act.

[0002] (Area of ​​disclosure) This disclosure relates to adjustable lenses, and more specifically, to a head-mounted display incorporating adjustable lenses for correcting a user's refractive errors. [Background technology]

[0003] (background) A wearable display system for augmented reality may include one or two eyepieces through which a user can view the world, and through which the display system can project digital images onto the user. The eyepieces are often formed using highly refractive materials and are typically designed to accommodate users with normal vision, i.e., without refractive errors.

[0004] For users with non-normal vision, such as nearsighted (myopia) or farsighted (hyperopia), custom-made inserts may be provided within a wearable display to correct the user's refractive error, for example, according to their ophthalmic prescription (Rx). Alternatively, the shape factor of the display may be designed to accommodate eyeglasses between the wearer and the eyepiece of the display. However, customizing the headset can be time-consuming and expensive, and the shape factor for accommodating eyeglasses may be too heavy, cumbersome, and aesthetically unappealing. [Overview of the project] [Means for solving the problem]

[0005] (summary) This disclosure features adjustable lenses that can be integrated into the eyepiece of a head-mounted display for correcting non-normal vision, particularly a head-mounted display for virtual reality. The eyepiece may include a fully integrated field-of-view configurable optical component arranged in relation to a waveguide used to project a digital image to the user, the optical component being able to provide an adjustable Rx for the user, including values ​​for variable spherical refractive power (SPH), cylindrical refractive power (CYL), and cylindrical axis (Axis). In one configuration, each adjustable eyepiece includes two variable composite lenses, one on the user side of the waveguide with variable sphere, cylinder, and axis, and the second on the world side of the waveguide with variable sphere. Collectively, the variable composite lenses can correct the user's refractive errors, including astigmatism, and position the digital image at an appropriate depth level relative to the environment and corresponding to the user's fixation depth.

[0006] In some embodiments, each composite lens comprises a plurality (e.g., two or three) variable cylindrical lenses. For example, each variable cylindrical lens may include a deformable refractive element integrated with an actuator. The actuator applies force to the deformable refractive element to vary the curvature of one or two surfaces of the lens, thereby varying the optical magnification of the cylindrical lens. An assembly of two such variable cylindrical lenses, whose cylindrical axes are oriented perpendicular to each other, may be used to provide a composite lens with adjustable spherical magnification. An assembly of three variable cylindrical lenses, whose cylindrical axes are oriented at 60° intervals, may be used to provide a composite lens with adjustable SPH, CYL, and Axis.

[0007] Disclosed herein is a system comprising: a first optical element comprising: a first refractive element arranged along an optical axis; and a first actuator arranged to vary the cylindrical refractive force of the first refractive element in response to a first control signal, wherein the first refractive element has a first cylindrical axis associated with the first refractive element along a first radial direction perpendicular to the optical axis; a second optical element comprising: a second refractive element arranged along an optical axis; and a second actuator arranged to vary the cylindrical refractive force of the second refractive element in response to a second control signal, wherein the second refractive element has a second cylindrical axis associated with the second refractive element along a second radial direction perpendicular to the optical axis; and A third optical element comprising a third refractive element and a third actuator arranged to vary the cylindrical refractive force of the third refractive element along a third radial direction perpendicular to the optical axis in response to a third control signal, wherein the first, second, and third radial directions are different, and an electronic controller communicating with the first, second, and third actuators, the electronic controller being configured to provide the first, second, and third control signals to the first, second, and third actuators during operation, thereby the first, second, and third refractive elements collectively form an optical element having an overall spherical refractive force (SPH), a cylindrical refractive force (CYL), and a cylindrical axis (Axis) according to a prescription (Rx).

[0008] In some implementations, the angular separation between the first and second radial directions may be equal to the angular separation between the second and third radial directions. For a Cartesian coordinate system perpendicular to the optical axis, the first radial direction may be 30°, the second radial direction 90°, and the third radial direction 150°. The first cylindrical refractive force C 30 , second cylindrical refractive force C 90 , and the third cylindrical refractive force C 150 The values ​​for S, C, and A are related according to the following formula.

number

[0009] At least one of the refractive elements may include a deformable optical material. The deformable optical material may be a solid optical material. The solid optical material may be an elastomer. The elastomer may be a silicon elastomer. At least one of the refractive elements includes a deformable transparent film adjacent to the deformable optical material, and actuators for at least one refractive element are arranged to deform the shape of the deformable transparent film in order to vary the cylindrical refractive force of at least one refractive element. The actuators bend the film about the cylindrical axis of at least one refractive element in order to vary the cylindrical refractive force of at least one refractive element. At least one of the refractive elements may include a rigid transparent substrate adjacent to the deformable optical material, on the opposite side of the refractive element from the deformable optical material. The optical element of at least one of the refractive elements may include a rigid gasket at the edge of the deformable optical material, and the deformable transparent film pivots on the rigid gasket when acted upon by the actuator. The cylindrical refractive powers of the first, second, and third optical elements can be varied over a range of -5D to +5D. 2 or greater than that (for example, 5cm) 2 Or more than that, 10cm 2 Or larger, 16cm 2 It has an aperture with an area (or greater than that). Each refractive element has a thickness along the optical axis of 10 mm or less (e.g., 6 mm or less, 4 mm or less, 3 mm or less, 2 mm or less, 1 mm or less).

[0010] Each optical element may comprise a pair of refractive elements, each refractive element of the pair having a cubic shape oriented along the axis in the radial direction of the optical element, and the actuators of the corresponding optical elements are arranged to slide the pair of refractive elements in opposite directions perpendicular to the optical axis.

[0011] In a second aspect, disclosed herein is a head-mounted display system comprising: a first optical element having a variable spherical refractive power (SPH); a second optical element having a variable SPH, a variable cylindrical refractive power (CYL), and a variable cylindrical axis (Axis); a see-through display arranged between the first optical element and the second optical element; and an electronic controller communicating with the first optical element, the second optical element, and the see-through display, the electronic controller being programmed to adjust the SPH of the first optical element, as well as the SPH, CYL, and Axis of the second optical element, according to an individual user prescription (Rx) of the head-mounted display.

[0012] The head-mounted display may further include a frame for mounting a first optical element, a second optical element, and a see-through display relative to each other and, during use, relative to the user of the head-mounted display. The second optical element may be arranged between the see-through display and the user during use of the head-mounted display. The first optical element may include two variable cylindrical lenses, each having its own separate cylindrical axis perpendicular to the other. The head-mounted display may further include an eye-tracking module, and an electronic controller is programmed to vary the prescription of the second optical element based on information about where the user of the head-mounted display may be looking from the eye-tracking module. The electronic controller may be programmed to vary the SPH, CYL, and Axis of the second optical element from a near vision prescription to a far vision prescription, depending on where the user may be looking. The head-mounted display may further include a biometric authentication module, and an electronic controller is programmed to verify the user's identity based on information from the biometric authentication module and adjust the prescription of the second optical element based on the user's identity. A biometric authentication module could be an iris-based identity verification module.

[0013] Among other advantages, the adjustable eyepiece can correct the user's unique optical prescription, including astigmatism, while minimizing power consumption and electromechanical overhead. The adjustable eyepiece can reduce the need to fabricate precision eyepieces customized for each user and increase the usability of users of virtual reality products with refractive errors. The built-in biometric module can authenticate the user based on their unique iris pattern and adjust the adjustable eyepiece to adapt to the prescriptions of multiple users within the field of view.

[0014] Other advantages will be apparent from the description, drawings, and claims. The present invention provides, for example, the following: (Item 1) It is a system, A first optical element comprising a first refractive element arranged along an optical axis and a first actuator arranged to vary the cylindrical refractive force of the first refractive element in response to a first control signal, wherein the first refractive element has a first cylindrical axis associated with the first refractive element along a first radial direction perpendicular to the optical axis, A second optical element comprising a second refractive element arranged along an optical axis and a second actuator arranged to vary the cylindrical refractive force of the second refractive element in response to a second control signal, wherein the second refractive element has a second cylindrical axis associated with the second refractive element along a second radial direction perpendicular to the optical axis, A third optical element comprising a third refractive element arranged along the optical axis, and a third actuator arranged to vary the cylindrical refractive force of the third refractive element along a third radial direction perpendicular to the optical axis in response to a third control signal, wherein the first, second, and third radial directions are different from the third optical element, An electronic controller communicating with the first, second, and third actuators, wherein the electronic controller is configured to provide the first, second, and third control signals to the first, second, and third actuators during operation, thereby the first, second, and third refractive elements collectively form an optical element having an overall spherical refractive power (SPH), cylindrical refractive power (CYL), and cylindrical axis (Axis) according to a prescription (Rx), and the electronic controller A system equipped with these features. (Item 2) The system according to item 1, wherein the angular separation between the first radial direction and the second radial direction is equal to the angular separation between the second radial direction and the third radial direction. (Item 3) The system according to item 1 or item 2, wherein, with respect to a Cartesian coordinate system perpendicular to the optical axis, the first radial direction is at 30°, the second radial direction is at 90°, and the third radial direction is at 150°. (Item 4) The first cylindrical refractive force C 30 , the second cylindrical refractive force C 90 , and the third cylindrical refractive force C 150 The values ​​for S, C, and A are related to the system described in item 3, according to the following formula.

Number

[0015] [Figure 1] Figure 1 is a schematic diagram of a wearable headset display.

[0016] [Figure 2] Figure 2 is a schematic diagram illustrating the rearward placement of the eye with an adjustable eyepiece, featuring proximal and distal adjustable optical elements.

[0017] [Figure 3] Figure 3A is a diagram of a composite lens used to correct non-normal vision, including spherical and cylindrical lenses. Figure 3B is a diagram of three cylindrical lenses representing an alternative means of correcting non-normal vision.

[0018] [Figure 4] Figure 4A is a schematic diagram depicting a side view of an exemplary refractive element that is not in operation. Figure 4B is a schematic diagram depicting a side view of an exemplary refractive element combined with a gasket and a aligned actuator.

[0019] [Figure 5] Figure 5A is a perspective view of the three components of the refractive element in a plano configuration. Figure 5B is a perspective view of the components of the refractive element shown in Figure 5A, which are operated to provide positive cylindrical magnification. Figure 5C is a perspective view of the components of the refractive element shown in Figure 5A, which are operated to provide negative cylindrical magnification.

[0020] [Figure 6] Figure 6 is a schematic diagram of six pairs of refractive elements with mirror-image cubic outlines in a sliding configuration. [Modes for carrying out the invention]

[0021] In the diagram, similar symbols represent similar elements.

[0022] (Detailed explanation) Figure 1 illustrates an exemplary head-mounted display system 60, which includes a see-through display 70 and various mechanical and electronic modules and systems for supporting the functionality of the display 70. The display 70 is wearable by a display system user 90 and is housed within a frame 80 configured to position the display 70 in front of the user's eyes. In some embodiments, the display 70 may be considered eyeglasses. In some embodiments, a speaker 100 is coupled to the frame 80 and positioned adjacent to the user's ear canal. The display system may also include one or more microphones 110 for sound detection. The microphones 110 may enable the user to provide input or commands (e.g., selection of voice menu commands, natural language questions, etc.) to the system 60 and / or enable voice communication with other persons (e.g., other users of similar display systems). The microphones 110 may also collect voice data (e.g., sounds from the user and / or the environment) from the user's surroundings. In some embodiments, the display system may also include ambient sensors 120a, which are separate from the frame 80 and can be attached to the user 90's body (e.g., head, torso, limbs, etc.). In some embodiments, the ambient sensors 120a may obtain data characterizing the user 90's physiological state.

[0023] In some embodiments, the display system may also include an eye tracking module 125a. In some embodiments, the eye tracking module 125a may include a biometric module to obtain the user 90's biometric data. In some embodiments, the biometric module may be an iris-based identity verification module.

[0024] In some embodiments, the eye tracking module 120a may obtain fixation depth data. The eye tracking module 120a may be operablely coupled by a communication link 125b (e.g., a wired or wireless connection) to the local processor and data module 140. The eye tracking module 120a may communicate biometric and fixation depth data to the local processor and data module 140.

[0025] The display 70 is operably coupled to a local data processing module 140 by a communication link 130, such as by a wired connection or wireless connection, which can be mounted in various configurations, such as being fixedly attached to a frame 80, fixedly attached to a helmet or hat worn by a user, embedded in headphones, or detachably attached to a user 90 (for example, in a backpack-type configuration or a belt-type configuration). Similarly, the sensor 120a may be operably coupled to the local processor and data module 140 by a communication link 120b (for example, by a wired connection or wireless connection). The local processing and data module 140 may include a hardware processor and digital memory such as non-volatile memory (for example, flash memory or a hard disk drive), both of which may be used to assist in data processing, caching, and storage. This data may include data captured from sensors such as image capture devices (e.g., cameras), microphones, inertial measurement units, accelerometers, compasses, GPS units, wireless devices, gyroscopes, and / or other sensors disclosed herein (e.g., operably coupled to frame 80 or otherwise attached to user 90), as well as / or 2) optionally, data obtained and / or processed using the remote processing module 150 and / or remote data repository 160 (including data related to virtual content) for passage to the display 70 after processing or reading. The local processing and data module 140 may be operably coupled to the remote processing module 150 and remote data repository 160 by communication links 170, 180, via wired or wireless links, etc., so that these remote modules 150, 160 are operably coupled to each other and available as resources to the local processing and data module 140. In some embodiments, the local processing and data module 140 may include one or more of the following: an image acquisition device, a microphone, an inertial measurement unit, an accelerometer, a compass, a GPS unit, a wireless device, and / or a gyroscope.In some other embodiments, one or more of these sensors may be standalone devices that can be mounted on the frame 80 or communicate with the local processing and data module 140 via a wired or wireless communication path.

[0026] The remote processing module 150 may include one or more processors for analyzing and processing data such as image and audio information. In some embodiments, the remote data repository 160 may be a digital data storage facility, which may be accessible via the Internet or other network configuration in a “cloud” resource configuration. In some embodiments, the remote data repository 160 may include one or more remote servers, which may provide information (e.g., information for generating augmented reality content) to the local processing and data module 140 and / or the remote processing module 150. In other embodiments, all data is stored, and all calculations are performed in the local processing and data module, enabling fully autonomous use from the remote module.

[0027] The variable eyepiece component, included with the display's eyepiece, adjusts the refractive power of the eyepiece to match the user's visual acuity to the user's fixation depth. The refractive power of the variable component can be set to different values ​​across a range of possible values, allowing it to function as a fixed lens with the added flexibility of controllable correction. The user's optical prescription (Rx) for correcting refractive errors is loaded into the headset controller, and the variable component can be modified to correct a unique set of parameters within it. The headset can perform this modification for each new user, thereby correcting each unique Rx.

[0028] Referring to Figure 2, the eyepiece 200 of the head-mounted display system directs light from the projector 220 to the user's eye 210. The projector 220 and the eyepiece 200 are positioned relative to each other and to the user's eye 210 by a frame or housing (not shown). The projector 220 is positioned near the user's temple and directs light to the end of the eyepiece 200 that extends beyond the user's temple. As shown, the eyepiece 200 includes a planar waveguide 240, an input coupled diffraction grating (ICG) 230, and an external coupling element (OCE) 250, however, more complex arrangements (e.g., consisting of multiple stacked waveguides) are also possible. A first variable focus assembly 270a is located on the world side of the waveguide 240, and a second variable focus assembly 270b is located on the user side. Collectively, the refractive powers of the variable focus assemblies 270a and 270b are adjusted to correct the optical properties of the eyepieces in parallel, taking into account the depth plane of the virtual image and the user's Rx.

[0029] ICG230 is a surface diffraction grating positioned to receive light from the projector 220 and facilitate the internal coupling of the light from the projector 220 into the eyepiece 200. ICG230 is located at or near the edge of the eyepiece 200 closest to the projector 220. ICG230 directs the light from the projector 220 into the waveguide modes within the planar waveguide substrate 240 of the eyepiece 200.

[0030] The planar waveguide substrate 240 guides the internally coupled light along the eyepiece 200 to the external coupling element (OCE) 250 through total internal reflection on its surface. The OCE 250 is a second surface diffraction grating configured to extract light outside the planar waveguide substrate 240 and redirect it toward the user's eye 210. The OCE 250 may include an exit pupil expander (EPE) or an orthogonal pupil expander (OPE), or both. The OCE 250 delivers light from the projector to an area positioned in front of the user's eye 210, where the user's pupil 212 can be positioned to receive the light output from the OCE 150. This area is referred to as the eyebox. The OCE 250 may further have lateral dimensions to accommodate a range of lateral positions of the eyebox. For example, the non-limiting range of the lateral dimension 251 of OCE250 may be 30 mm or less (e.g., 25 mm or less, 20 mm or less, 15 mm or less).

[0031] Arranged on the user-facing surface of the eyepiece 200, the variable focus assembly 270b corrects the user's non-normal visual acuity, including astigmatism. In addition, the variable focus assembly 270b sets the focus of the eyepiece 200 in the corrected depth plane in order to display a virtual image. This setting of focus also affects the focus of the real image that passes to the user through the display. Arranged on the world-facing surface of the eyepiece 200, the variable focus assembly 270a corrects the setting of the real image resulting from the correction by the variable focus assembly 270b. The variable focus assembly 270a includes two optical elements 271a and 271b, while the variable focus assembly 270b includes three optical elements 271c, 271d, and 271e.

[0032] In some embodiments, each optical element 271a-e includes a refractive element incorporating a deformable optical material in contact with a deformable film. The refractive elements are coupled to actuators 272a-e, which operate to change the refractive force of the connected optical elements 271a-e, as further described in Figure 4. The actuator 272 deforms, for example, at least one surface of the corresponding refractive element along a single axis, thereby allowing the refractive element of optical element 271 to function as a variable cylindrical lens. In some embodiments, the actuators may be piezoelectric actuators.

[0033] Actuators 272a-e apply force in response to control signals from controller 274. In one implementation, the headset controller 274 performs calculations to determine the refractive force for each optical element 271a-e. The lens shape of each optical element 271a-e is combined to establish the refractive force of the variable focus assembly 270a or 270b. The optical magnification for the variable focus assembly may vary based on various considerations, including the user's Rx, the user environment, the projected image, and / or a combination of these parameters.

[0034] In some embodiments, the controller 274 may receive biometric data from the eye tracking module and adjust the refractive power of the variable focus assembly 270b to correct the user's Rx based on that biometric data. In some embodiments, the controller 274 may receive user fixation depth data from the eye tracking module and adjust the refractive power of the variable focus assembly 270b to correct the user's near or far vision Rx. Similarly, the controller 274 may receive user fixation depth data from the eye tracking module and adjust the lens shape of the variable optical element 270a to adjust the optical depth of the virtual image to match the fixation depth for the user.

[0035] Generally, the human eye can have refractive errors that lead to conditions such as nearsightedness, farsightedness, astigmatism, or combinations thereof. These refractive errors are corrected by using corrective lenses to correct the incident light. Nearsightedness or farsightedness occurs when the projected image of the eye is not in focus with the posterior plane of the eye, and is typically corrected through a lens with a "spherical" shape placed between the eye and the incident light. In a broad sense, a plano-spherical lens shape can be considered a planar division of a spherical surface, resulting in a lens shape with two opposing surfaces, namely a curved surface and a planar surface. The curved surface of a spherical lens is radially symmetrical about a central axis oriented perpendicular to the planar surface. Lenses with a spherical shape, aligned along the optical axis of the user's eye, correct these refractive errors.

[0036] Astigmatism is a refractive error caused by the lens of the eye having differential curvature along different directions. Lenses with a "cylindrical" shape can correct this type of abnormality. A plano-cylindrical lens shape can be considered a planar division of a cylinder, viewed parallel to the longitudinal axis of the cylinder. This results in a lens with opposing curved surfaces (e.g., convex) and planar surfaces. The longitudinal axis along the center of the planar surfaces is called the cylindrical axis. The curved surfaces have equal radii of curvature along the length of the cylindrical shape.

[0037] Typically, lenses with spherical and cylindrical components are used to correct refractive errors in astigmatic, non-emmetropic eyes. An ophthalmic prescription (Rx) combines the spherical, cylindrical, and cylindrical-axial components (SPH, CYL, Axis), which are the refractive powers of the spherical and cylindrical lenses, as well as the orientation of the cylindrical axis, respectively. A Cartesian coordinate system, oriented perpendicular to the optical axis with 0° and directed horizontally, can be used to define the cylindrical axis.

[0038] Spherical or cylindrical lenses have individual powers or refractive powers, typically measured in diopters (D). The refractive power of a lens can be zero, a negative number (e.g., divergent), or a positive number (e.g., converging). While not necessarily constrained by theory, the refractive power can be equal to the reciprocal of the focal length (f), i.e., D = 1 / f. For example, a lens with a refractive power of +3D will guide parallel rays from optical infinity to focus at 1 / 3 meter. Furthermore, for example, a flat or planar lens has a refractive power of 0D and does not converge or diverge light.

[0039] Rx can be represented by a combination of a spherical lens and a cylindrical lens, as shown in Figure 3A. Depicted is an exemplary assembly of a spherical lens 310 with refractive power S and a cylindrical lens 312 with refractive power C. The cylindrical axis 313 of the cylindrical lens 312, oriented at an angle A with respect to the horizontal plane, is shown. Although we do not wish to be constrained by theory, the phase outline at a point (x, y) on the surface of any Rx is:

number

[0040] The corrective force of the spherical lens 310 can, alternatively, be achieved by a pair of cylindrical lenses 312 whose cylindrical axes are oriented at a 90° angle to each other. Therefore, the combination of spherical lens 310 and cylindrical lens 312 shown in Figure 3A is also achievable through a combination of three cylindrical lenses. Figure 3B shows the individual refractive power C 30 , C 90 , and C 150 This describes an array of three cylindrical lenses 312a, 312b, and 312c, whose cylindrical axes are aligned radially at 30°, 90°, and 150° from the horizontal plane of the eye. Although we do not wish to be constrained by theory, the refractive power C required to correct Rx using spherical and cylindrical components is... 30 , C90 , and C 150 This can be determined for each individual lens using the following:

number

[0041] Based on the above, the optical elements 271a-e described in Figure 2 can function as cylindrical lenses, and they can be oriented and combined within the optical elements to achieve a desired Rx.

[0042] While arrangements of cylindrical axes aligned radially at 30°, 90°, and 150° are described and would work for the three elements Rx (e.g., SPH, CYL, Axis), these orientations are not the only solutions that can provide correction for astigmatic non-normal visual acuity. In general, there are many sets of angles that would give sufficient degrees of freedom to match the three parameters of Rx. For example, three cylindrical axes oriented at 0°, 60°, and 120° (e.g., from the horizontal plane of the eye) can also correct such Rx. This arrangement maintains a 60° separation between the cylindrical axes as described in Figure 3B. However, as a further embodiment, three cylindrical lenses with cylindrical axes separated by 45° (e.g., 0°, 45°, 90°) can also provide the necessary correction for the three elements Rx.

[0043] In general, the sum of the angular separations between the three cylindrical axes of a set of cylindrical lenses may be sufficient to eliminate redundancy between two or more cylindrical lenses. For example, the sum of the angular separations between the three cylindrical axes may be in the range of 45° to 180°. The angular displacement of the central of the three cylindrical axes may be approximately equal to that of the other two (for example, the central axis may be 45° from the other two for a sum of 90° angular separations), or the cylindrical axes may be separated by unequal angles.

[0044] In general, various optical elements capable of providing a variable cylindrical lens can be used for the variable focus assembly depicted in Figure 2. One embodiment is shown in Figures 4A and 4B, which shows an optical element 400 comprising a deformable transparent film 410, a transparent substrate 412, a deformable optical material 414, and a gasket 416 around the edge of the deformable optical material 414. The deformable transparent film 410, the deformable optical material 414, and the substrate 412 together form a variable cylindrical lens with an optical axis 420 perpendicular to the cylindrical axis, which extends perpendicular to the plane of the figure. The thickness of the optical element 400 is 10 mm or less (e.g., 6 mm or less, 4 mm or less, 3 mm or less, 2 mm or less, 1 mm or less). Relatively thin optical elements can preferably provide a compact and lightweight device suitable for integration into head-mounted displays.

[0045] The optical element 400 also includes actuators 472, which are arranged to change the cylindrical refractive power of the optical element.

[0046] The deformable transparent film 410 is positioned in contact with the upper edge of the rigid gasket 416 and the upper surface of the optical material 414. The contact elements of the actuator 472 are positioned in contact with the opposite side of the film 410. The transparent film 410 consists of a transparent material that can be deformed (e.g., bent) when a force is applied. Exemplary materials include inorganic glass such as borosilicate glass, or plastic films such as thin-film polycarbonate. The thickness of the transparent film 410 is sufficient to provide protection to the optical material 416, while still remaining flexible. For example, the transparent film may be about 0.1 mm or thinner.

[0047] The gasket 416 surrounds the edge and encloses the optical material 414 up to a common height. The gasket 416 suppresses the lateral expansion and contraction of the material 414 when the optical element 271 is actuated. The gasket 416 further encloses a partially transparent substrate 412 to form an aperture through which light passes along the optical axis 420. In some embodiments, this aperture is 1 cm 2 or greater than that (for example, 5cm) 2 Or more than that, 10cm 2 Or larger, 16cm 2 It may have a visible area (or larger).

[0048] Arranged between the substrate 412 and the film 410 is a deformable optical material 414. The optical material 414 consists of a low-hardness material that is substantially transparent to light in visible light. In some embodiments, the optical material may be a solid optical material such as an elastomer. For example, materials such as silicon elastomer or gel may be used for the optical material 414. Other materials measuring 10-50 (e.g., 10-40, 10-30, 10-20, 20-50, 30-50, or 40-50) on a 000-scale Shore hardness scale may also be considered.

[0049] The rigid transparent substrate 412 provides a rigid base for the deformable optical material 414 and extends across the entire inner width of the rigid gasket 416. The rigid transparent substrate 412 is made of a material that maintains its shape under the force applied by the deformable optical material 414 and is substantially transparent to light in visible light. For example, the substrate 412 may be formed from plastic or inorganic glass. The substrate 412 may have a thickness of 1 mm or less (e.g., 0.8 mm or less, 0.6 mm or less, 0.4 mm or less, 0.2 mm or less).

[0050] In Figure 4A, the optical element 400 is shown in an inactive state, with a deformable film 410 having an infinite radius of curvature, for example, a refractive force of 0. In response to the operation by the actuator 472, the deformation of the film 410 compresses or expands the optical material 414, thereby changing the refractive force of the optical element.

[0051] Referring here to Figure 4B, an actuator 272 mechanism is shown, aligned with the rigid gasket 416 and positioned in contact with the outer edge of the film 410 of the refractive element 400. The actuator 272 pivots on the gasket 416 to apply a parallel and common force, thereby deforming the film 410 along an axis parallel to the edge of the gasket 416 and its center. This deformation changes the radius of curvature of the film 410, causing it to bend. The actuator 272 causes the film 410 to become concave or convex, correlating with positive or negative refractive forces, respectively. The axis around which deformation occurs is the cylindrical axis of the optical element. In the embodiment of Figure 4B, the axis extends perpendicularly outward from the plane of the page.

[0052] Illustrations of these variations are shown in Figures 5A–C. Figure 5A depicts a refractive element 500, similar to those depicted in Figures 4A and 4B, showing only the transparent film 510, the rigid substrate 512, and the optical material 514. A Cartesian coordinate system 530 is shown on the left side of Figure 5A for context. The optical axis for the refractive element 500 is parallel to the z-axis of the coordinate system 530. A change in the radius of curvature of the film 510 relative to the cylindrical axis 520, which is perpendicular to the optical axis, causes compression or expansion of the optical material 514, resulting in a change in the refractive force of the refractive element 500. A change in the radius of curvature of the film 510 causes a positive or negative cylindrical refractive force. For example, the cylindrical refractive force may be variable throughout the range of -5D to +5D (e.g., -4D, -3D, -2D, -1D, 0D, 1D, 2D, 3D, or 4D). The refractive force of a cylinder can vary in gradual increments of 0.1D or more (e.g., 0.2D or more, such as 0.25D or 0.5D) from, for example, -5D to +5D.

[0053] Figure 5A depicts the refractive element 500 in an unacted state, while Figures 5B and 5C depict the refractive element 500 in an actuated state. Figure 5B shows the refractive element 500 actuated along a cylindrical axis 520 to create a convex plano-cylindrical lens. The lens in Figure 5B provides a positive cylindrical refractive force (e.g., 1D, 2D, 3D, or 4D). Figure 5C shows the same exemplary refractive element 500 actuated to form a concave plano-cylindrical lens that provides a negative cylindrical refractive force (e.g., -4D, -3D, -2D, or -1D).

[0054] Other assemblies that operate as variable cylindrical lenses are also possible. For example, in another embodiment, a variable focus assembly consists of a sliding pair of rigid refractive elements (e.g., molded or polished elements formed from glass or plastic), each pair operating as a variable cylindrical lens. An example is shown in Figure 6, which depicts a variable focus assembly 600 including three pairs of refractive elements 620, 621, and 622. Specifically, pair 620 consists of refractive elements 620a and 620b, pair 621 consists of refractive elements 621a and 621b, and pair 622 consists of refractive elements 622a and 622b. Insertion projection axes oriented along the x, y, and z axes are shown in Figure 6.

[0055] Each refractive element (620a, b, and 621a, b, and 622a, b) has a planar surface and an opposing two-dimensional cubic surface. In general, the cubic surface is a surface defined by a cubic polynomial, e.g., a cubic polynomial. Refractive elements with cubic surfaces can be constructed by a combination of positive and negative cylindrical lens outlines with similar radii of curvature. The resulting surfaces closely follow a cubic polynomial. The cubic surface of one refractive element in a pair faces the second refractive element of the pair, whose cubic surface is a mirror image of the first refractive element. With aligned cubic vertices, the pair of refractive elements function as lenses with zero refractive power. When the cubic vertices of the lenses are translationally misaligned, the refractive element will refract light passing through it onto the focal line, thereby performing the effect of a variable cylindrical lens.

[0056] Each pair of refractive elements, for example, refractive elements 620a and 620b, are separated by a distance that allows the refractive elements to be translated parallel to each other without the cube surfaces touching. In the exemplary embodiment of Figure 6, refractive elements 620a and 620b can be translated parallel to each other along a certain distance without the cube surfaces touching. This distance depends on the depth of the cubic outline of the pair of refractive elements. The refractive elements 620a and 620b, as well as 621a and 621b, and 622a and 622b, are generally made of a rigid, transparent material such as inorganic glass (e.g., borosilicate glass) or a suitable plastic (e.g., polycarbonate).

[0057] In a typical embodiment, using optical element 620, the total thickness of optical element 620 may be 10 mm or less, including the individual thicknesses of refractive elements 620s and 620 and their separation distance, as described above. The cubic outlines of refractive elements 620a and 620b are oriented along a common radial axis perpendicular to the optical axis, equivalent to the cylindrical axis described above. In this configuration, optical element 620 can function as a variable cylindrical lens. Optical element 620 in contact with linear actuator 630 is shown. Actuator 630 operates to translate refractive elements 620a and 620b in opposite directions along the common axis perpendicular to the optical axis.

[0058] For example, the linear actuator 630 can translate the refractive element 620b relative to 620a to create a positive or negative refractive force. A mismatch in the mirror-image cubic shape of the refractive element in one direction will result in a positive refractive force (e.g., 1D, 2D, 3D, 4D, or 5D). A mismatch in the mirror-image cubic shape of the refractive element in the opposite direction will result in a negative cylindrical refractive force (e.g., -1D, -2D, -3D, -4D, or -5D).

[0059] The three optical elements 620, 621, and 622 are shown with cylindrical axes corresponding to 150°, 90°, and 30° from the horizontal plane of the eye, similar to the lens in Figure 3B. In other words, the cylindrical axes are oriented on the xy plane at 150°, 90°, and 30° from the x-axis, respectively. The dashed lines on the cubic surfaces of the refractive elements 620b, 621b, and 622b are aligned with the individual cylindrical axes of the optical elements 620, 621, and 622. Each optical element 620, 621, and 622 is shown in contact with the linear actuators 630, 631, and 632. As described above, any three refractive elements, with their individual cubic outlines corresponding to 150°, 90°, and 30° from the horizontal plane of the eye, perform correction for any user's ophthalmic prescription, as in the exemplary system in Figure 6. Similarly, any two such optical elements with cubic vertices oriented at right angles to each other would function as a spherical lens. For example, such an array could be used to perform adjustment of the virtual image plane for a variable focus assembly 270a.

[0060] Several embodiments are described. Other embodiments are also included in the following claims.

Claims

1. It is a system, A waveguide configured to output light to the user's eyes, wherein the waveguide has a user side and a world side, The first variable focus assembly located on the user side, wherein the first variable focus assembly is A first optical element comprising a first refractive element arranged along an optical axis and a first actuator arranged to vary the cylindrical refractive force of the first refractive element in response to a first control signal, wherein the first refractive element has a first cylindrical axis associated with the first refractive element along a first radial direction perpendicular to the optical axis, A second optical element comprising a second refractive element arranged along the optical axis and a second actuator arranged to vary the cylindrical refractive force of the second refractive element in response to a second control signal, wherein the second refractive element has a second cylindrical axis associated with the second refractive element along a second radial direction perpendicular to the optical axis, A third optical element comprising a third refractive element arranged along the optical axis, and a third actuator arranged to vary the cylindrical refractive force of the third refractive element along a third radial direction perpendicular to the optical axis in response to a third control signal, wherein the first radial direction, the second radial direction, and the third radial direction are different from each other, and A first variable focus assembly comprising, A second variable focus assembly located on the world side, wherein the second variable focus assembly is A fourth optical element comprising a fourth refractive element arranged along the optical axis and a fourth actuator arranged to vary the cylindrical refractive force of the fourth refractive element in response to a fourth control signal, wherein the fourth refractive element has a fourth cylindrical axis associated with the fourth refractive element along a fourth radial direction perpendicular to the optical axis, A fifth optical element comprising a fifth refractive element arranged along the optical axis and a fifth actuator arranged to vary the cylindrical refractive force of the fifth refractive element in response to a fifth control signal, wherein the fifth refractive element has a fifth cylindrical axis associated with the fifth refractive element along a fifth radial direction perpendicular to the optical axis, and A second variable focus assembly comprising, An electronic controller communicating with the first actuator, the second actuator, and the third actuator, wherein the electronic controller is configured to provide the first control signal, the second control signal, and the third control signal to the first actuator, the second actuator, and the third actuator, respectively, during operation, so that the first, second, and third refractive elements collectively form an optical element having the overall SPH, CYL, and Axis according to a prescription (Rx) including the spherical refractive power (SPH), cylindrical refractive power (CYL), and astigmatism axis (Axis), and the electronic controller A system equipped with these features.

2. The system according to claim 1, wherein the angular separation between the first radial direction and the second radial direction is equal to the angular separation between the second radial direction and the third radial direction.

3. The system according to claim 1, wherein, with respect to a Cartesian coordinate system perpendicular to the optical axis, the first radial direction is at 30°, the second radial direction is at 90°, and the third radial direction is at 150°.

4. The first cylindrical refractive force C ３０ and the second cylindrical refractive force C ９０ and the third cylindrical refractive force C １５０ And the values ​​of S, C, and A are [Number 10] The system according to claim 3, relating to the formula shown above.

5. The system according to claim 1, wherein at least one of the refractive elements includes a deformable optical material.

6. The system according to claim 5, wherein the deformable optical material is a solid optical material.

7. The system according to claim 6, wherein the solid optical material is an elastomer material.

8. The system according to claim 7, wherein the elastomer material is a silicon elastomer.

9. The system according to claim 5, wherein at least one of the refractive elements comprises a deformable transparent film adjacent to the deformable optical material, and the actuator of the at least one refractive element is arranged to deform the shape of the deformable transparent film in order to vary the cylindrical refractive force of the at least one refractive element.

10. The system according to claim 9, wherein the actuator bends the film about the cylindrical axis of the at least one refractive element in order to vary the cylindrical refractive force of the at least one refractive element.

11. The system according to claim 9, wherein at least one of the refractive elements comprises a rigid, transparent substrate adjacent to the deformable optical material, on the opposite side of the refractive element from the deformable optical material.

12. The system according to claim 9, wherein at least one of the refractive elements is provided with a rigid gasket on the edge of the deformable optical material, and the deformable transparent film pivots on the rigid gasket when acted upon by the actuator.

13. The system according to claim 1, wherein the cylindrical refractive powers of the first optical element, the second optical element, and the third optical element are variable over a range of -5D to +5D.

14. The optical element is 1 cm ２ The system according to claim 1, having an opening having the above area.

15. The system according to claim 1, wherein each of the refractive elements has a thickness of 10 mm or less along the optical axis.

16. The system according to any one of claims 1 to 4, wherein each optical element comprises a pair of refractive elements, each of the pair of refractive elements having a cubic shape oriented along the radial axis of the optical element, and the actuators of the corresponding optical elements are arranged to slide the pair of refractive elements in opposite directions perpendicular to the optical axis.

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