Vision correction and field of view extension with optical metasurfaces

Abstract

Devices for vision correction and field of view extension with optical metasurfaces are disclosed. In one embodiment, vision correction device for extending a user's field of view to restore peripheral vision is provided, the vision correction device comprising a metasurface configured to redirect a light path of an incident light extending a field of view of a user to restore peripheral vision; and wherein the metasurface is integrated onto an optical substrate.

Description

VISION CORRECTION AND FIELD OF VIEW EXTENSION WITH OPTICAL METASURFACESCROSS-REFERENCE TO RELATED APPLICATION

[0001] The current application claims priority to U.S. Provisional Patent Application No. 63 / 642,957, filed on May 6, 2024, the disclosure of which is incorporated herein by reference.FIELD OF THE INVENTION

[0002] The present invention generally relates to medical devices and more specifically to methods and devices for vision correction and field of view extension utilizing optical metasurfaces.BACKGROUND

[0003] Eye diseases such as, but not limited to, glaucoma, where the peripheral vision is lost, can prevent patients from doing tasks that are needed on a daily basis. For example, walking without proper peripheral vision can lead to tripping, falling and other types of collisions. In addition, they are not aware of their surroundings as keen as individuals with normal vision, thus must turn their head to view peripherals, lowering their reaction time. In particular, driving is greatly impacted by such diseases, as not being able to see 45 degrees (in the peripheral field of view) from centerline can greatly increase the chances of car accidents, leading to injury or death. In other eye diseases or injuries such as hemianopia, where the patient can lose half of their vision in one or both eyes due to nerve or brain damage, similar or even greater hindrances to daily functions may occur.SUMMARY OF THE INVENTION

[0004] The various embodiments of the present devices for vision correction and field of view extension utilizing optical metasurfaces (may be referred to herein collectively as “optical metasurface devices” or “vision correction devices”) contain several features, no single one of which is solely responsible for their desirable attributes. Without limiting the scope of the present embodiments, their more prominent features will now be discussed below. In particular, the present optical metasurface devices will be discussed in the context of metasurfaces (may also bereferred to as “optical metasurfaces”) integrated on contact lens and / or glasses for improving peripheral vision and correcting blindness. However, the use of particular devices (e.g., contact lens and glasses) and particular optical metasurfaces are merely exemplary and various other implementations and / or metasurfaces may be utilized as appropriate to the requirements of a specific application in accordance with various embodiments of the invention. Further, the use of correcting a particular eye disease (e.g., glaucoma) is also merely exemplary and various other applications including the correction of various eye diseases utilizing optical metasurfaces may be considered as appropriate to the requirements of a specific application in accordance with various embodiments of the invention. After considering this discussion, and particularly after reading the section entitled “Detailed Description,” one will understand how the features of the present embodiments provide the advantages described herein.

[0005] One aspect of the present embodiments includes the realization that there are currently, outside of the present embodiments, no efficient eye wear devices to improve peripheral vision. Attempts had been made to develop items to place on the glasses such as mirrors or prisms. These devices are limited to the 45-degree angle from the center point which limits the full range of view a patient can obtain. These devices also do not display the view in a continuous fashion, which leaves gaps in their field of view. In addition, because of the bulkiness of the such devices, bringing in vision from all angles (i.e., up, down, left, and right) simultaneously is not possible. Nor can these devices be integrated into a more compact fashion such as ultrathin glasses and contact lenses.

[0006] Another aspect of the present embodiments includes the realization that the present optical metasurface devices provide various benefits and advantages such as, but not limited to, providing continuous field of view (FOV). Because the previous prior art devices involve mirrors or prisms, there are often gaps in such devices leading to missing sections of view. Further, the present embodiments provide for stronger light steering at steeper angles. The current limitations of prior art devices include the loss at angles higher than 40 degrees. This is because of the total internal reflection of such devices. Metasurfaces have stronger power at angles steeper than 40 degrees than those that involve prisms or mirrors. Furthermore, the present embodiments provide for a smaller profile. Because the metasurfaces typically work in the submicron scale (for the visible wavelengths), the device may include parts that are thinner than a micro, which is ~ 10,000times smaller than any other devices on the market. This also allows for the potential patterning on contact lenses for even more compact design. Moreover, the present embodiments may allow for multiuse. Because of the myriad of shapes that can be patterned using metasurfaces, the types of beam steering and light manipulation can be catered to the individual patient. In addition, the present embodiments may allow for electrical tunablility. Furthermore, optical metasurfaces can potentially be tuned for dynamic steering / focusing, scanning, and / or formatting dynamic images.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The various embodiments of the present optical metasurface devices now will be discussed in detail with an emphasis on highlighting the advantageous features. These embodiments depict the novel and non-obvious features of optical metasurface devices shown in the accompanying drawings, which are for illustrative purposes only. These drawings include the following figures:

[0008] Fig. 1 is a diagram illustrating an overview of an ultrathin active meta-optics for extreme light bending and / or focusing for next generation vision correction technologies in accordance with an embodiment of the invention.

[0009] Fig. 2a is a schematic diagram illustrating a cylindrical metasurface optimized to steer light in 60 degrees in accordance with an embodiment of the invention.

[0010] Fig. 2b a diagram illustrating normalized intensity of transmitted light demonstrating effective steering to 60 degrees in accordance with an embodiment of the invention.

[0011] Fig. 3 is a diagram illustrating a sample design for 550nm light for a beam steering angle of 45° (image is not to scale) in accordance with an embodiment of the invention.

[0012] Fig. 4a is a diagram illustrating a double metasurface for large angle light deflection with high efficiency in accordance with an embodiment of the invention.

[0013] Fig. 4b is a schematic diagram illustrating electrically tunable optical metasurfaces in accordance with an embodiment of the invention.

[0014] Fig. 5a is a diagram illustrating optical metasurfaces with advanced optical functions, electrical tunability, and integration with AR / VR technologies for vision correction in accordance with an embodiment of the invention.

[0015] Fig. 5b are diagrams illustrating electrical tunability of metasurfaces in accordance with an embodiment of the invention.

[0016] Fig. 6a is a diagram illustrating a metasurface with discrete unit elements in accordance with an embodiment of the invention.

[0017] Figs. 6b-c are diagrams illustrating corrected direction of an incident beam as it passes through the metasurface of Fig. 6a in the transverse-electric (TE) and transverse-magnetic (TM) polarizations, respectively, in accordance with an embodiment of the invention.

[0018] Fig. 7a is a diagram illustrating examples of two freeform metasurface designs in accordance with an embodiment of the invention.

[0019] Fig. 7b is a diagram illustrating a steering path of the freeform design (500nm height) in accordance with an embodiment of the invention.

[0020] Fig. 8 is a block diagram illustrating a machine learning (ML) process for developing freeform metasurfaces in accordance with an embodiment of the invention.

[0021] Fig. 9a is diagram illustrating a first freeform metasurface unit cell produced using a ML process in accordance with an embodiment of the invention.

[0022] Fig. 9b is diagram illustrating a second freeform metasurface unit cell produced using a ML process in accordance with an embodiment of the invention.

[0023] Fig. 9c is a diagram illustrating incident light of three different simulations (2 simulations at 45°) in accordance with an embodiment of the invention.

[0024] Fig. 9d is a diagram illustrating beam steering capabilities based on light that is normal incident for the first freeform metasurface in accordance with an embodiment of the invention.

[0025] Fig. 9e is a diagram illustrating beam steering capabilities based on light that is 45° incident in the TE mode for the first freeform metasurface in accordance with an embodiment of the invention.

[0026] Fig. 9f is a diagram illustrating beam steering capabilities based on light that is 45° incident in the TM mode for the first freeform metasurface in accordance with an embodiment of the invention.

[0027] Fig. 9g is a diagram illustrating beam steering capabilities based on light that is normal incident for the second freeform metasurface in accordance with an embodiment of the invention.

[0028] Fig. 9h is a diagram illustrating beam steering capabilities based on light that is 45° incident in the TE mode for the second freeform metasurface in accordance with an embodiment of the invention.

[0029] Fig. 9i is a diagram illustrating beam steering capabilities based on light that is 45° incident in the TM mode for the second freeform metasurface in accordance with an embodiment of the invention.

[0030] Fig. 10 is a block diagram illustrating an optical metasurface device in accordance with an embodiment of the invention.DETAILED DESCRIPTION OF THE DRAWINGS

[0031] The following detailed description describes the present embodiments with reference to the drawings. In the drawings, reference numbers label elements of the present embodiments. These reference numbers are reproduced below in connection with the discussion of the corresponding drawing features.

[0032] Turning now to the drawings, devices for vision correction and field of view extension utilizing optical metasurfaces (may be referred to herein collectively as “optical metasurface devices”) are provided. The present embodiments may allow for extreme bending and re-directing of light to aid the progressive peripheral vision blindness in glaucoma and other eye diseases thereby providing significant advances over any available eyewear technology. In many embodiments, optical metasurface devices may merge the advantages of metasurfaces (e.g., ultrathin optical metasurfaces) and active optical materials (e.g., optical lenses such as, but not limited to glasses, contact lens, etc.) to re-direct the light path and widen the field of vision to restore peripheral vision for patients with eye diseases. In various embodiments, the present embodiments may also be utilized with augmented reality (AR) and / or virtual reality (VR), as further described below. The present embodiments provide for next generation vision correction technologies and could impact the quality of life of potentially billions of people who suffer from partial or serious visual loss and blindness. An overview of next generation vision correction in accordance with embodiments of the invention are discussed further below.Next Generation Vision Correction

[0033] In many embodiments, optical metasurfaces with sub-micron structures may be utilized to manipulate light in unique fashions. The sub-micro structures may take various forms of structure, such as, but not limited to, a cylinder, cross, square, etc. In various embodiments, the sub-micro structures may be placed on a surface such as, but not limited to, glass or silicon, for example. Depending on the pattern of these structures, they can manipulate light in different ways, such as, but not limited to, splitting light (beam splitter), beam deflection, and / or light focusing. In various embodiments, the metasurfaces may be utilized so that the light coming in at various angles (e.g., between approximately 80-15-degree angles offset from the forward point of view) is directed into the field of view for patients that have lost that area of their vision.

[0034] When optical metasurfaces with sub-micro structures (may also be referred to herein as “metasurfaces”) are applied onto a device such as glasses or contact lenses, the user (may also be referred to as the “person”) would be provided with an increase in their field of view. Utilizing metasurfaces, such extensions in field of view can be done in all directions. In addition, such metasurfaces can be implemented on contact lenses, in an even more compact form than utilized on glasses. Further, electrically tunable metasurfaces may also be used to enhance the image formation and to be integrated with AR / VR technology for advanced vision correction.

[0035] A diagram illustrating an overview of ultrathin active meta-optics for extreme light bending and / or focusing for next generation vision correction technologies in accordance with an embodiment of the invention is shown in Fig. 1. The top portion of the diagram illustrates a first view 102 of a scene by a person with a “normal” vision and a second view 104 of the same scene by a person with limited vision (e.g., with advanced glaucoma). As shown in the second view 104, the person with advanced glaucoma has a limited FOV as they have blind spots in their peripheral vision.

[0036] In further reference to Fig. 1, a center beam of light 114 illustrates how light in front of user would land in a limited vision person’s eye 110 thus allowing a person with limited vision to still see things in front of them. However, a peripheral beam of light 106 illustrates how light in the peripheral would land in the blind spot 108 of the person’s eye 110 (without the use of the optical metasurface devices). Typically, such persons are limited to a tunnel vision as depicted by boundaries 116, 118. In various embodiments, the tunnel vision may appear as a constricted circular tunnel-like FOV. In many embodiments, the optical metasurface device 120 may includean ultrathin active meta-optics 122 (may also be referred to herein as “optical metasurfaces”) that may be applied onto contact lenses and / or glasses 123. In a variety of embodiments, the optical metasurface device 120 may extend a user’s FOV by bending light that would normally would have been received in the user’s blind spot 108 or blind spot 109 (without the use of the optical metasurface devices), but instead, the light is redirected into the user’s FOV. For example, a redirected arrow 124 illustrates how a beam of light is “bent” and redirected from out of view to now into the FOV of the user. Thus, allowing for extended peripheral vision. For example, the optical metasurfaces 122 may provide for an extended field of view as depicted by the boundaries 132, 134.

[0037] Furthermore, in many embodiments, the optical metasurfaces 122 may provide various advantages, such as, but not limited to, complex and / or advance optical functions, high optical power (e.g., deflection angle), electrically tunable for better optical range, programmable wavefront shaping, etc. In addition, optical metasurfaces 122 may be electrically tunable and be fabricated on optical fibers, as further described below.

[0038] Although specific active meta-optics for extreme light bending and / or focusing for next generation vision correction technologies are discussed above with respect to Fig. 1, any of a variety of active meta-optics as appropriate to the requirements of a specific application may be utilized in accordance with embodiments of the invention. Active optical metasurfaces in accordance with embodiments of the invention are discussed further below.Optical Metasurfaces

[0039] The flat nature of metasurfaces (typical thickness < 100 nm) may enable two-dimensional optical elements to form flat and ultrathin optical elements such as, but not limited to, lenses and beam deflection elements.

[0040] In many embodiments, to construct active optical metasurfaces, first, a meta-element may be numerically designed to achieve large phase control and a high angle of refraction to shift the field of view from a non-seeing toward a seeing field via electromagnetic wave and ray tracing simulations. For example, simulation results may show that a large angle deflection with more than 60 degrees with efficiency > 90% could be obtained using a single metasurface configuration, which is not possible using any bulky prism.

[0041] Fig. 2a is a schematic diagram illustrating a cylindrical metasurface optimized to steer light in 60 degrees in accordance with an embodiment of the invention. In some embodiments, active optical metasurfaces may be periodic structures including, but not limited to, periodic cylindrical structures. Further, by having a phase gradient between individual elements, the light can be steered to its desired direction. As described further herein, the present embodiments provide for such designs and use in various fields including, but not limited to, the medical field for optical sight correction.

[0042] In reference to Fig. 2a, the metasurface region 200 may include cylinders (e.g., TiCh nanocylinders) of varying diameter. For example, the metasurface region 200 may include a first nanocylinder 202 having a first diameter, a second nanocylinder 204 having a second diameter, and a third nanocylinder 206 having a third diameter, where the first, second, and third diameters are not equal. In some embodiments, the third diameter may be larger than the second diameter, and the second diameter may be larger than the first diameter. In some embodiments, the metasurface region 200 may include a repeating pattern of nanocylinders having a first, second, and third diameters. In many embodiments, the metasurface region 200 may deflect an input beam 208 resulting in an output beam 212 that has a specific off-axis angle 210 (e.g., 60°).

[0043] The present embodiments may further optimize these metasurfaces for both performance and fabrication. For example, in some embodiments, performance has been confirmed at an operating wavelength of 633nm (visible red light), maintaining the above efficiency values despite the finer structure needed. In some embodiments, to aid in fabrication, the metasurface thickness (pillar height) may be limited (e.g., to 600nm), and the aspect ratio (height / width) may be limited to < 6, leading to more consistent and high-quality nanostructures in the finished product.

[0044] A diagram illustrating normalized intensity of transmitted light demonstrating effective steering to 60 degrees in accordance with an embodiment of the invention is shown in Fig. 2b. The diagram 250 illustrates normalized intensity of the transmitted light in the far field vs. angle after interacting with metasurface regions with a steering angle of 60°. The spike 252 in diagram 250 demonstrates the effective steering to the 60° angle.

[0045] Active optical metasurfaces may be configured for various degrees of beam steering. For example, a design for a 45 -degree beams steering metasurface to be implemented on glasses may be constructed utilizing a plurality of cylinders (e.g., three individual cylinders). In someembodiments, the plurality of cylinders (e.g., the three cylinders) may make up a unit cell. In some embodiments, unit cells may be repeated across an entire substrate where that substrate has the same beam steering angle. For example, the unit cells may be placed and / or repeated on the substrate by fusing and / or integrating the unit cells with the substrate. If there is a different beam steering angle that is desired on another part of the substrate (e.g., on another part of the glasses), then a differing unit cell (e.g., a unit cell that corresponds to that beam steering angle), may also be utilized. For example, one part of the glasses and / or contacts may have a first beam steering angle and another part of the glasses and / or contacts may have a second beam steering angle.

[0046] A diagram illustrating a sample design for 550nm light for a beam steering angle of 45° (image is not to scale) in accordance with an embodiment of the invention is shown in Fig. 3. The design may include a first cylinder 302, a second cylinder 304, and a third cylinder 306. Further, the first, second, and third cylinders 302, 304, 306 with the 45-degree steering angle may have the radii of 50nm, 91nm, and 105nm, respectively. In various embodiments, the individual unit cells may be separate by a predetermined distance. For example, the first cylinder 302 and the second cylinder 304 may have a first predetermined distance 308 of 225nm. In addition, the second cylinder 304 and the third cylinder 306 may have a second predetermined distance 310 of 225nm. In many embodiments, the predetermined distance (e.g., the predetermined distances 308, 310) between a cylinder to the next cylinder, depending on the phase change of each element, may determine the beam steering angle. In many embodiments, the phase change between the unit cells (e.g., between the cylinders) may be approximately 2pi / 3 , corresponding to a full 2pi phase change over the course of the unit cell. This may allow for the beam steering to take place. In various embodiments, a 2pi phase shift between a full wavelength may correspond to the 45-degree steering angle.

[0047] The unit cells for the glasses design may be constructed using materials such as, but not limited to titanium dioxide (TiCh), a high index material that allows for the phase change in the incident light to take place. In many embodiments, deep ultraviolet lithography and nanofabrication techniques may be used to fabricate large-area dielectric metasurface on glass and polymer surfaces. In some embodiments, deep ultraviolet techniques may allow for structure sizes (<100nm) to achieve a desired light steering angle. In some embodiments, double metasurfaces fabricated on the top and bottom of a glass may be utilized to create large deflection angles. Forexample, in order to further increase the efficiency, particularly for steering angles above 60°, the present embodiments may also utilize a double-layer metasurface structure, with two distinct metasurfaces (e.g., TiCh metasurfaces) separated by a thin layer of glass.

[0048] A diagram illustrating a double metasurface (e.g., a first metasurface and a second metasurface) for large angle light deflection with high efficiency in accordance with an embodiment of the invention is shown in Fig. 4a. The double-layer metasurface structure 400 may include a first metasurface 402 and a second metasurface 404 that may be separated by a layer of flat glass 406. In this way, the burden of beam deflection may be split between the two metasurfaces 402, 404, allowing for two more efficient designs to be used in place of one lossy one. For example, the first metasurface 402 may deflect an input beam 408 resulting in an intermediate deflected beam 410 and the second metasurface 204 may deflect the intermediate deflected beam 410 resulting in an output beam 412. For various steering angles, the present embodiments may achieve nearly double the efficiency using this technique as compared to a single-layer metasurface design. Although specific beam deflection angles are provided herein, the present embodiments may be utilized for various different angles and continuous angles. Further, although TiCh is utilized as the dielectric material, the present embodiments may utilize a variety of dielectric materials beyond those specifically referenced herein.

[0049] In many embodiments, the metasurfaces may be configured for various parameters including, but not limited to, beam steering angles, refraction vs pass-through, etc. A schematic diagram illustrating electrically tunable optical metasurfaces in accordance with an embodiment of the invention is shown in Fig. 4b. The metasurface 450 may be integrated onto an optical substrate 452. The metasurface 450 may receive an incident light 454 and produce an output light such as, but not limited to, a refracted output light 456 and / or a pass-through output light 458 which have been redirected (e.g., beam steered) by a controllable angle.

[0050] In reference to Fig. 4b, the metasurface 450 may include a plurality of rows (or columns or any pattern) of metasurface unit cells, with each row having a connection (e.g., an electrode connection) to an electrical control such as, but not limited to, voltage controls. In various embodiments, the plurality of electrode connections may provide various voltages corresponding to specific beam steering angles. For example, a first voltage Vi 460 may control a first row, a second voltage V2462 may control a second row, a third voltage V3 464 may control a third row,a forth voltage V4 466 may control a forth row, a fifth voltage V5 468 may control a fifth row, a sixth voltage V6410 may control a sixth row, a seventh voltage V7412 may control a seventh row, an eighth voltage Vs 414 may control an eighth row, a ninth voltage V9 416 may control a ninth row, etc.

[0051] In some embodiments, the metasurface 450 may be an electrically-tunable conducting oxide metasurface that may be integrated into the optical substrate 452 that may be an eye-glass surface for dynamic manipulation of the complex optical wavefront. For example, in contact lens embodiments, a polymer membrane that holds the metasurface may be transferred and thermally fused to the contact lens. In some embodiments, light redirection with the meta-optical glass (e.g., the combination of the metasurface 450 and optical substrate 452) may be performed with sufficient efficiency of the deflected beam while maintaining a normal view.

[0052] An active optical metasurface provides dynamic control of the transmitted, reflected, or diffracted wavefronts, including individual or simultaneous control of the optical phase, amplitude, polarization state, and spectral / temporal / spatial responses, enabling new optical functions such as, but not limited to, dynamic beam steering. Significant attempts have been made in the last few years to realize metasurfaces with controllable amplitude and phase modulation, using both alternative materials and novel tuning mechanisms. Alternative materials may include, but is not limited to, conducting oxide materials, liquid crystals, two-dimensional materials, phase change materials, etc. Such tunable version of metasurfaces may be integrated so that the light beam can be actively controlled with selected angle / di recti on for vision correction purposes.

[0053] Although active optical metasurfaces and fabrication processes are discussed above with respect to Figs. 2a-4b, any of a variety of active optical metasurfaces and fabrication processes as appropriate to the requirements of a specific application may be utilized in accordance with embodiments of the invention. Optical metasurface devices in accordance with embodiments of the invention are discussed further below.Optical Metasurface Devices

[0054] Optical metasurface devices may include active optical metasurfaces combined with glasses and / or contact lens. In some embodiments, optical metasurface devices may also include so-called smart glasses features including, but not limited to, AR / VR features. In someembodiments, optical metasurface devices may include a camera configured to capture image / video and a projector (e.g., a nano-projector or micro-projector) configured to deliver realtime images to the patient’s eyes using the strongly deflected metaoptics to create images into the eye’s normal visual field.

[0055] A diagram illustrating optical metasurfaces with advanced optical functions, electrical tunability, and integration with AR / VR technologies for vision correction in accordance with an embodiment of the invention is shown in Fig. 5a. The optical metasurface device 500 may include a frame 501 with a pair of glasses (e.g., a first glass 503 and a second glass 505). In many embodiments, the first glass 503 may include a tunable metasurface 508 (may also be referred to herein as the “active optical metasurface”), as further described herein. The optical metasurface device 500 may also include a camera 502 configured to capture image data in a field of view 504. In some embodiments, the optical metasurface device 500 may also include a projector (e.g., a micro-projection 506) configured to receive the image data from the camera 502 and project light 507 at the first glass 503, where the tunable metasurface 508 may refract the light 507 to the user’s eye (e.g., a left eye 516). In many embodiments, the tunable metasurface 508 may steer the light 507 for vision correction, as further described herein. For example, the light 507 may include a first beam 512, a second beam 510, and a third beam 514. The first beam 512 may be steered by the tunable metasurface 508 to avoid the user’s first blind spot 518. Likewise, the third beam 514 may be steered by the tunable metasurface 508 to avoid the user’s second blind spot 520. Further, the second beam 510 may be steered to the first and / or second blind spots 518, 520.

[0056] In reference to Fig. 5a, although not illustrated for clarity purposes, in some embodiments, the optical metasurface device 500 may include a second camera that captures second image data of a second field of view. In some embodiments, the second field of view may overlap with the field of view 504 (may also be referred to as a “first field of view”) of the camera 502 (may also be referred to as a “first camera”). In some embodiments, the optical metasurface device 502 may include a second projector (e.g., a second micro-projector) that receives the second image data and projects light to the second glass 505 having a second tunable metasurface for steering light from the second projector to the user’s other eye (e.g., the right eye), as further described above. In some embodiments, the optical metasurface device 502 may have a single camera positioned anywhere on the frame 501 and may include one or more projectors forprojecting light carrying the image data to the metasurface(s) of the first and / or second glasses for vision correction.

[0057] Diagrams illustrating electrical tunability of metasurfaces in accordance with an embodiment of the invention is shown in FIG. 5b. In reference to diagram 550, the metasurface 552 may be integrated onto an optical substrate 554. The metasurface 552 may be electrically tunable using electrical controls (e.g., voltage controls), as further described above. For example, the metasurface 552 may include a group (e.g., a row, column, or any pattern) of metasurface unit cells that may be controlled by one or more voltage levels. For example, the metasurface 552 may include a first group of unit cells that are controlled by a first voltage Vi, a second group of unit cells that are controlled by a second voltage V2, a third group of unit cells that are controlled by a third voltage V3, and forth group of unit cells that are controlled by a forth voltage V4. In some embodiments, one voltage level may control more than one group of unit cells.

[0058] In reference to Fig. 5b, the metasurface 554 may receive an incident light 564 and produce an output light such as, but not limited to, a first output light 566 and / or a second output light 568 which have been redirected (e.g., beam steered) by a controllable angle. For example, as illustrated, the first output light 566 may be the result of the first voltage Vi 566 and the second output light 568 may be the result of the second voltage V2558.

[0059] In further reference to Fig. 5b, diagram 570 illustrates, with sizing scales, an electrical tunable metasurface. As further described above, an electrically tunable metasurface may include electrode connections (e.g., electrode connection 572) that allows for voltage controls. In addition, in some embodiments, the metasurface may also include one or more antennas 574 that may be used to receive the control levels such as, but not limited to, the voltage controls.

[0060] A block diagram illustrating an optical metasurface device 1000 is shown in FIG. 10. The optical metasurface device 1000 may include a first optical substrate 1002 such as, but not limited to, a first glass (e.g., a left eye glass, left contact lens, etc.). The first optical substrate 1002 may include a first metasurface 1004 that may be integrated onto a first side of the first optical substrate 1002, as further described herein. For example, the first metasurface 1004 may be placed on a front or back side of the first optical substrate 1002. In many embodiments, the first metasurface 1004 may be configured to redirect a light path of an incident light from a user’s blind spot (or any degraded portion of the user’s eye) to a working field of view of the user thereby restoring theuser’s peripheral vision. In some embodiments, the first optical substrate 1002 may also include a second metasurface 1006 that may be integrated onto a second side of the optical substrate 1002. For example, the second metasurface 1006 may be placed on the back or front side of the optical substrate 1002 that is opposite to the side that the first metasurface 1004 is on. The second metasurface 1006 may also be configured to redirect a light path of an incident light from a user’s blind spot (or any degraded portion of the user’s eye) to a working field of view of the user. In some embodiments, the first and / or second metasurfaces 1004, 1006 may be configured to refract a projected light from a projector, as further described herein.

[0061] In reference to Fig. 10, the optical metasurface device 1000 may also include a second optical substrate 1008 such as, but not limited to, a second glass (e.g., a right eye glass, right contact lens, etc.). The second optical substrate 1008 may include a first metasurface 1010 that may be integrated onto a first side of the second optical substrate 1008, as further described herein. For example, the first metasurface 1010 may be placed on a front or back side of the second optical substrate 1008. In many embodiments, the first metasurface 1010 may be configured to redirect a light path of an incident light from a user’s blind spot (or any degraded portion of the user’s eye) to a working field of view of the user thereby restoring the user’s peripheral vision. In some embodiments, the second optical substrate 1008 may also include a second metasurface 1012 that may be integrated onto a second side of the second optical substrate 1008. For example, the second metasurface 1012 may be placed on the back or front side of the second optical substrate 1008 that is opposite to the side that the first metasurface 1010 is on. The second metasurface 1012 may also be configured to redirect a light path of an incident light from a user’s blind spot (or any degraded portion of the user’s eye) to a working field of view of the user. In some embodiments, the first and / or second metasurfaces 1010, 1012 may be configured to refract a projected light from a projector, as further described herein.

[0062] In further reference to Fig. 10, the optical metasurface device 1000 may also include one or more cameras 1014 configured to capture image data 1030 of a field of view, as further described herein. In addition, the optical metasurface device 1000 may include one or more projectors 1016 configured to project the image data 1030 to the second metasurface 1006 and / or the second metasurface 1012, where the projected image is refracted back into the field of view of the user, as further described herein.

[0063] In further reference to Fig. 10, the optical metasurface device 1000 may also include a processing module 1020 that may include a processor 1022, a volatile memory 1024, and a nonvolatile memory 1026. The non-volatile memory 1026 may store an application 1028 that configures the optical metasurface device 1000 to perform various actions such as, but not limited to, capturing the image data 1030 using the camera(s) 1014, projecting the image data 1030 using the projector(s) 1016, etc. In many embodiments, the optical metasurface device 1000 may store the image data 1030 in the non-volatile memory 1026.

[0064] In further reference to Fig. 10, the non-volatile memory 1026 may also store other types of data, such as, but not limited to, AR / VR data 1034. For example, in some embodiments, the optical metasurface device 1000 may be configured to receive AR / VR data 1034 using a communication module 1018. In many embodiments, the communication 1018 may allow the optical metasurface device 1000 to transmit and / or receive data via the Internet or directly (e.g., with a client device). In some embodiments, the communication module 1018 may provide for a wireless and / or wired connection. In some embodiments, the optical metasurface device 1000 may be configured to project the AR / VR data 1034 to the user. In some embodiments, the optical metasurface device 1000 may project the AR / VR data 1034 to the second metasurface 1006 and / or the second metasurface 1012, where the projected image is refracted back into the field of view of the user, as further described herein.

[0065] In various embodiments, optical metasurface device 1000 may be controlled via a client device. For example, users may use an application running on a client device to control various feature of the optical metasurface device 1000 such as, but not limited to, tuning and controlling the beam steering angles of the metasurfaces. In some embodiments, the client device and the optical metasurface device 1000 may be connected via a direct connection, such as, but not limited to, Bluetooth®.

[0066] Although specific optical metasurface devices for vision correction are discussed above with respect to Figs. 5a- 10, any of a variety of optical metasurface devices for vision correction as appropriate to the requirements of a specific application may be utilized in accordance with embodiments of the invention. Additional metasurfaces and optimization considerations in accordance with embodiments of the invention are discussed further below.Metasurfaces and Optimization Considerations

[0067] As described above, metasurfaces may be utilized for beam steering for individuals with vision impairment. Through optimizations of various metasurface designs, advancements for utilization may be achieved.

[0068] A diagram illustrating a metasurface with discrete unit elements in accordance with an embodiment of the invention is shown in Fig. 6a. The metasurface 600 may include a plurality of discrete unit elements 602 which may be laid out in an array along a substrate 604 such as, but not limited to, a glass substrate. A close-up 606 of a unit element is provided. In many embodiments, the unit element 602 may include various structures such as, but not limited to, 3 distinct cylinders that includes a first cylinder 610 have a first radius n, a second cylinder 612 having a second radius r2, and a third cylinder 614 having a third radius n. The cylinders 610, 612, 614, may each be separated by distance from their centers. For example, the first cylinder 610 may be separated by a distance di from the second cylinder 612. Further, the second cylinder 612 may be separated by a distance d2 from the third cylinder 614. In some embodiments, the distances di and d2 may be equal. In some embodiments, the distances di and d2 may be different.

[0069] In reference to Fig. 6a, the metasurface 600 may receive an incoming incident beam (e.g., a 45° incident light 620) and correct direction by steering and producing an output light 622 that lands on the user’s working field of view 624 and avoid the user’s damaged field of view 626.

[0070] Diagrams illustrating corrected direction of an incident beam as it passes through the metasurface of Fig. 6a in the transverse-electric (TE) and transverse-magnetic (TM) polarizations, respectively, in accordance with an embodiment of the invention are shown in Figs. 6b-c. In reference to Fig. 6b, the diagram 650 highlights the original direction of the beam as the incident path 652. The optimized devices shift the angle of this incident light across almost all wavelengths to just left of 0 degrees in the new guided path 654. Similarly, in reference to Fig. 6c, the diagram 660 highlights the original direction of the beam as the incident path 662. The optimized devices shift the angle of this incident light across almost all wavelengths to just left of 0 degrees in the new guided path 664. The main difference between the two polarizations is the beam steering efficiency at different wavelengths, but the steering angle remains the same for both.

[0071] In reference to Figs. 6b-c, in some embodiments, when the metasurface to an incident beam is at a 45-degree angle, the metasurface demonstrates significant steering towards the leftside of the far field. This result demonstrates the device’s functionality, as it shows the potential to expand the visual field for patients with vision loss, previously lost through diseases such as, but not limited to, glaucoma, hemianopia, stroke, etc.

[0072] The simulations illustrate that in a broad range of wavelengths (approximately 400- 600nm) we have effective beam steering to the working field of view with an efficiency between 40-50%. Furthermore, the structure is virtually polarization independent, which is much more representative of white light that is typically viewed every day. In some embodiments, the overall height of the cylinders may be 850nm, making it virtually 2D when imprinted on glasses, many orders of magnitude thinner than conventional devices.

[0073] Although specific metasurfaces and optimization considerations are discussed above with respect to Figs. 6A-C, any of a variety of metasurfaces and optimization considerations as appropriate to the requirements of a specific application may be utilized in accordance with embodiments of the invention. Freeform Designs and ML considerations in accordance with embodiments of the invention are discussed further below.Freeform Metasurfaces and ML Considerations

[0074] The present embodiments leverage versatile metasurfaces capable of beam wavefront manipulation offering a solution by facilitating the redirection of light from virtually any direction, particularly within a range of 45 degrees or less, tailored to the specific areas of vision impairment experienced by patients. While a structured configuration (e.g., cylindrical 3-unit configuration) effectively redirects the beam by up to 50% towards the working visual field, the present embodiments may also include the exploration of a "freeform" design approach. This innovative surface geometry may be engineered through various processes such as, but not limited to, an "inverse design," empowered by various machine learning techniques.

[0075] In many embodiments, such processes may include employing a freeform design approach, utilizing machine learning with a gradient decent method to optimize the desired output. Initially, various wavelengths may be selected. For example, three wavelengths (400nm, 550nm, and 700nm) spanning the visible spectrum may be selected. A series of RCWA simulations may then be conducted to enhance beam steering efficiency at the first order diffraction angle (e g., 45 degrees) for these wavelengths. From the initial simulations a figure of merit is determinedfollowed by adjustments to the unit cell shape based on simulation outcomes, with subsequent simulations to refine the design further. This process may be iterated until the network has found a minimum in a defined cost function. Upon completion, the network may generate shapes (e.g., illustrated in Fig. 7a) for validation using various methods, including, but not limited to, Lumerical FDTD to assess beam steering effects (e.g., as depicted in Fig. 7b).

[0076] A diagram illustrating examples of two freeform metasurface designs in accordance with an embodiment of the invention is shown in Fig. 7a. The freeform metasurface designs 700 and 710 may utilize various medium of patterning such as, but not limited to, TiCh. In addition, the freeform metasurface designs 700, 710 may utilize various substrate medium such as, but not limited to, SiCh. The freeform metasurface design 700 may have a height 702 (e.g., 300nm in height) a width 704 (e.g., 275 nm) and a length 706 (e.g., 778 nm). The freeform metasurface design 710 may have a height 712 (e.g., 500nm in height) a width 714 (e.g., 275 nm) and a length 716 (e.g., 778 nm). The freeform metasurface designs may be unit cells that may be repeated to create the metasurface, as further described above.

[0077] A diagram illustrating a steering path of the freeform design 710 (500nm height) in accordance with an embodiment of the invention is shown in Fig. 7b. As illustrated in diagram 720, the freeform design 710 steers the beam at more consistent angles than the 3-unit cylinder design, but the overall concept of repeat patterns to steer the wavefront remains the same.

[0078] Figs. 7a-b showcases the unit cells representing the core element of various implementations. In some embodiments, the freeform unit cells may replace the three-cylinder design. In some embodiments, the freeform unit cells may be used in conjunction with the three- cylinder design. In some embodiments, the unit cells are intended for replication across surfaces, such as glasses or contacts. While both cylindrical and freeform designs effectively realign incident light from a 45-degree angle to an optimal 0-degree orientation, the freeform designs may offer a distinct advantage in maintaining beam steering angle consistency across various wavelengths compared to its cylindrical counterpart. Moreover, both designs demonstrate comparable efficiency levels, ranging from 40% to 50% across a broad spectrum of wavelengths. The design material in all of the unit cells shown here is TiO2; however, any transparent high index medium could be used to achieve similar effects. Whether employing the cylindrical three-unit cell or freeform design, the overarching goal remains consistent: guiding incident beams effectively to the desired working field of view for patients with vision impairment.

[0079] Metasurface designs utilizing a structured configuration (e.g., a three-element cylinder unit cell) may facilitate manufacturing simplicity. In some embodiments, while this configuration enables ease of fabrication, it may impose limitations, including restricted operational bandwidth for beam steering and low efficiency (<50%), even when employing high-refractive-index materials such as titanium dioxide (TiCL). Additionally, such designs may exhibit pronounced chromatic aberrations, particularly when correcting an incidence angle of 45 degrees relative to normal (0 degrees). Furthermore, resonant wavelength absorption within the metasurface may result in strong attenuation in specific portions of the operational bandwidth, thereby reducing effective transmission.

[0080] In many embodiments, limitations of various configurations such as, but not limited to, a structured configuration (e.g., a three-element unit cell) may be overcome by employing a machine-learned (ML) metasurface architecture optimized using gradient descent techniques.

[0081] A block diagram illustrating an ML process for developing freeform metasurfaces in accordance with an embodiment of the invention is shown in Fig. 8. The optimization process 800 may begin with an image of noise, z 802. The process 800 may also include applying a Fourier transform (FFT) 804, followed by a blurring kernel 806 (and applying FFT 808) to eliminate high- frequency noise. In some embodiments, the output of the FFT 804, 808 may be multiplied 810. The process 800 may also include performing an inverse Fourier transform (IFFT) 812, yielding a noise-based initial metasurface. Using this metasurface, simulations (e.g., a Rigorous Coupled- Wave Analysis (RCWA) 814) may be conducted for normal incidence with various wavelengths including, but not limited to, 400 nm, 550 nm, and 700 nm, and the transmission may be monitored and compared to a figure of merit (FOM) 816. In many embodiments, the FOM 816 for optimization may be a transmission efficiency at a 45-degree deflection angle. The process may also include calculating gradients 818. In some embodiments, the calculated gradients 818 may be used to modify the noise 820. In some embodiments, the FFT 804 may be applied to the updated noise 820, and the process 800 may be repeated iteratively until convergence 822 is achieved, resulting in an optimized metasurface design.

[0082] In many embodiments, freeform metasurfaces may be made of silicon nitride (SiN), which, despite having a lower refractive index than TiCL, may offer enhanced compatibility with large-area metasurfaces; however, any large refractive index dielectric can be used. Unlike designs constrained to predefined geometric structures such as cylinders, squares, or crosses, the freeform designs may utilize an amorphous unit cell structure generated through ML optimization. This unit cell may be systematically repeated across an entire metasurface to achieve the desired optical functionality.

[0083] The disclosed embodiments illustrate specific designs; however, over 50 iterations have been optimized within a target wavelength range of 400-700 nm. The unit cell dimensions are approximately 275 nm x 778 nm. The optimized metasurface effectively corrects 45-degree incident light across all wavelengths, achieving efficiencies exceeding 50% and reaching >70% at specific wavelengths, as illustrated in Figs. 9a-i. For example, a diagram illustrating a first freeform metasurface unit cell 900 produced using a ML process in accordance with an embodiment of the invention is shown in Fig. 9a. In addition, a diagram illustrating a second freeform metasurface unit cell 910 produced using a ML process in accordance with an embodiment of the invention Fig. 9b.

[0084] A diagram illustrating an incident light of three different simulations (2 simulations at 45°) in accordance with an embodiment of the invention is shown in Fig. 9c. The freeform metasurface 920 may include a plurality of freeform metasurface unit cells such as, but not limited to the first freeform metasurface unit cell 900 or the second freeform metasurface unit cell 910. In many embodiments, the freeform metasurface 920 may be laid out in an array along a substrate 922 such as, but not limited to, a glass substrate. In reference to Fig. 9c, the metasurface 920 may receive an incoming 45° incident light 924 and correct direction by steering and producing an output light 928. Further, metasurface 920 may receive an incoming normal incident light 930 and correct direction by steering and producing an output light 932.

[0085] A diagram 940 illustrating beam steering capabilities based on light that is normal incident for the first freeform metasurface (i.e., a metasurface constructed with the first freeform metasurface unit cells 900) in accordance with an embodiment of the invention is shown in Fig. 9d. A diagram 950 illustrating beam steering capabilities based on light that is 45° incident in the TE mode for the first freeform metasurface in accordance with an embodiment of the invention isshown in Fig. 9e. A diagram 960 illustrating beam steering capabilities based on light that is 45° incident in the TM mode for the first freeform metasurface in accordance with an embodiment of the invention is shown in Fig. 9f.

[0086] A diagram 970 illustrating beam steering capabilities based on light that is normal incident for the second freeform metasurface (i.e., a metasurface constructed with the second freeform metasurface unit cells 910) in accordance with an embodiment of the invention is shown in Fig. 9g. A diagram 980 illustrating beam steering capabilities based on light that is 45° incident in the TE mode for the second freeform metasurface in accordance with an embodiment of the invention is shown in Fig. 9h. A diagram 990 illustrating beam steering capabilities based on light that is 45° incident in the TM mode for the second freeform metasurface in accordance with an embodiment of the invention Fig. 9i.

[0087] The metasurfaces described herein hold promise for medical treatment applications, particularly for patients with vision blind spots. Due to their ability to deliver high-efficiency beam steering with minimal thickness (approximately 700 nm or less), designs incorporating electrically tunable metasurfaces can be integrated with optical devices, such as, but not limited to, AR and / or VR systems, to create more compact and highly efficient optical metasurface devices. For example, utilizing optical metasurface devices in conjunction with AR / VR capabilities may significantly enhance medical treatment impact by enabling control over patient-specific blind spot areas.

[0088] Although specific freeform metasurfaces and ML considerations are discussed above with respect to Figs. 7a-9i, any of a variety of freeform metasurfaces and ML considerations as appropriate to the requirements of a specific application may be utilized in accordance with embodiments of the invention. While the above description contains many specific embodiments of the invention, these should not be construed as limitations on the scope of the invention, but rather as an example of one embodiment thereof. It is therefore to be understood that the present invention may be practiced otherwise than specifically described, without departing from the scope and spirit of the present invention. Thus, embodiments of the present invention should be considered in all respects as illustrative and not restrictive.

Claims

WHAT IS CLAIMED IS:

1. A vision correction device for extending a user’s field of view to restore peripheral vision, the vision correction device comprising: a metasurface configured to redirect a light path of an incident light extending a field of view of a user to restore peripheral vision; and wherein the metasurface is integrated onto an optical substrate.

2. The vision correction device of claim 1, wherein the metasurface comprises submicron structures.

3. The vision correction device of claim 2, wherein the sub-micron structures are cylinder, cross, or square shaped structures.

4. The vision correction device of claim 2, wherein the sub-micron structures are periodic cylindrical structures having a phase gradient between the cylindrical structures to beam steer the light path of the incident light.

5. The vision correction device of claim 1, wherein the metasurface is constructed using a plurality of unit cells.

6. The vision correction device of claim 5, wherein each of the plurality of unit cells are repeated across the optical substrate to produce a particular beam steering angle.

7. The vision correction device of claim 6, wherein the plurality of unit cells comprises a first cylinder having a first radius, a second cylinder having a second radius, and a third cylinder having a third radius.

8. The vision correction device of claim 6, wherein the plurality of unit cells comprises freeform unit cells, wherein the freeform unit cells are generated using machine learning with a gradient decent method for optimization.

9. The vision correction device of claim 7, wherein the plurality of unit cells are placed a predetermined distance apart from each other.

10. The vision correction device of claim 5, wherein the plurality of unit cells are constructed using a high index material that allows for a phase change in the incident light.

11. The vision correction device of claim 10, wherein the high index material is titanium dioxide TiCh.

12. The vision correction device of claim 1, wherein the optical substrate is eye glasses.

13. The vision correction device of claim 1, wherein the optical substrate is contact lens.

14. The vision correction device of claim 12, wherein the metasurface is integrated onto the optical substrate using deep ultraviolet lithography and nanofabrication processes.

15. The vision correction device of claim 12, wherein the metasurface is integrated onto a surface of the eye glasses for dynamic manipulation of complex optical wavefront.

16. The vision correction device of claim 13, wherein the metasurface is integrated onto a polymer membrane that holds the metasurface, and the polymer membrane is transferred and thermally fused to the contact lens.

17. The vision correction device of claim 1, wherein the metasurface redirects the light path coming in at angles between 80-15 degrees offset of a forward point of view into the field of view of the user.

18. The vision correction device of claim 1 , wherein the metasurface has a thickness < 100 nm.

19. The vision correction device of claim 1 further comprising a second metasurface, wherein the metasurface is integrated onto a first side of the optical substrate and the second metasurface is integrated onto a second side of the optical substrate, thereby creating a double metasurface.

20. The vision correction device of claim 19, wherein the metasurface and the second metasurface comprises21. The vision correction device of claim 19, wherein the double metasurface is electronically tunable.

22. The vision correction device of claim 20 further comprising a camera configured to capture image data.

23. The vision correction device of claim 21 further comprising a projector operatively connected to the camera, wherein the proj ector is configured to proj ect the image data to the second metasurface, wherein the projected image is refracted back into the field of view of the user.

24. The vision correction device of claim 22, wherein the camera and the projector are configured for augmented reality and / or virtual reality.

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