WO2025059150A1 - Apparatuses and systems for pancharatnam-berry phase augmented-gradient index liquid crystal lenses - Google Patents

Abstract

The disclosed apparatus may include a varifocal lens, where the transmissivity of the varifocal lens changes in relation to the optical power of the varifocal lens; and a transmissivity compensation component that is configured to change as the optical power of the varifocal lens changes, such that a variation of transmissivity of the varifocal lens is less than a variation of transmissivity of the varifocal lens in combination with the transmissivity compensation component. Various other apparatuses, systems, and methods are also disclosed.

Description

APPARATUSES AND SYSTEMS FOR PANCHARATNAM-BERRY PHASE AUGMENTED

GRADIENT-INDEX LIQUID CRYSTAL LENSES

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority under 35 U.S.C. §119(e) of U.S. Provisional Application No. 63/582,306, filed September 13, 2023.

FIELD OF THE DISCLOSURE

[0002] The present disclosure is generally directed to apparatuses and systems in which a transmissivity compensation component augments a varifocal lens.

BACKGROUND OF THE DISCLOSURE

[0003] Gradient-index liquid crystal ("GRIN LC") lens designs can allow for dynamically adjustable optical power. However, in these designs, transmittance may vary with optical power. However, for many user experiences it may be important to keep varifocal power independent from brightness.

[0004] The present disclosure seeks to address, at least in part, any or all of the drawbacks and disadvantages described above.

SUMMARY OF THE DISCLOSURE

[0005] According to a first aspect of the present disclosure there is provided an apparatus comprising: a varifocal lens, wherein the transmissivity of the varifocal lens changes in relation to the optical power of the varifocal lens; and a transmissivity compensation component that is configured to change as the optical power of the varifocal lens changes, such that a variation of transmissivity of the varifocal lens is less than a variation of transmissivity of the varifocal lens in combination with the transmissivity compensation component.

[0006] In some embodiments, the varifocal lens may be planar; and the transmissivity compensation component may be planar.

[0007] In some embodiments, the varifocal lens may comprise a gradient-index liquid crystal lens.

[0008] In some embodiments, the transmissivity compensation component may comprise a Pancharatnam-Berry phase element.

[0009] In some embodiments, the apparatus may further comprise control circuitry that transmits a signal to the transmissivity compensation component that regulates a transmissivity of the transmissivity compensation component.

[0010] In some embodiments, the control circuitry may generate the signal based at least in part on at least one of: a signal received by the control circuitry to change an optical power of the varifocal lens; a signal received by the control circuitry indicating a change to the optical power of the varifocal lens; or a signal received by the control circuitry indicating a change to a transmissivity of the varifocal lens.

[0011] In some embodiments, a change in the transmissivity of the varifocal lens in relation to the optical power of the varifocal lens may be non-uniform across the varifocal lens.

[0012] In some embodiments, the transmissivity compensation component may be configured to change as the optical power of the varifocal lens changes such that a nonuniformity of transmissivity of the varifocal lens may be less than a non-uniformity of transmissivity of the varifocal lens in combination with the transmissivity compensation component.

[0013] In some embodiments, a change in the transmissivity of the varifocal lens in relation to the optical power of the varifocal lens may vary radially across the varifocal lens.

[0014] In some embodiments, the transmissivity compensation component may be configured to change with a radial distribution across the transmissivity compensation component as the optical power of the varifocal lens changes.

[0015] According to a second aspect of the present disclosure there is provided a system comprising: a lens apparatus, comprising: a varifocal lens, wherein the transmissivity of the varifocal lens changes in relation to the optical power of the varifocal lens; and a transmissivity compensation component that is configured to change as the optical power of the varifocal lens changes, such that a variation of transmissivity of the varifocal lens is less than a variation of transmissivity of the varifocal lens in combination with the transmissivity compensation component; an accommodation module; and a head-mounted display.

[0016] In some embodiments, the head-mounted display may comprise a virtual image display.

[0017] In some embodiments, the accommodation module may be on an eye side of the display; and the varifocal lens and the transmissivity compensation component may be on the world side of the display.

[0018] In some embodiments, the varifocal lens may comprise a gradient-index liquid crystal lens.

[0019] In some embodiments, the transmissivity compensation component may comprises a Pancharatnam-Berry phase element.

[0020] In some embodiments, the system may further comprise control circuitry that transmits a signal to the transmissivity compensation component that regulates a transmissivity of the transmissivity compensation component.

[0021] In some embodiments, the control circuitry may generate the signal based at least in part on at least one of: a signal received by the control circuitry to change an optical power of the varifocal lens; a signal received by the control circuitry indicating a change to the optical power of the varifocal lens; or a signal received by the control circuitry indicating a change to a transmissivity of the varifocal lens.

[0022] In some embodiments, a change in a transmissivity of the varifocal lens in relation to the optical power of the varifocal lens may be non-uniform across the varifocal lens.

[0023] In some embodiments, the transmissivity compensation component may be configured to change as the optical power of the varifocal lens changes such that a nonuniformity of transmissivity of the varifocal lens may be less than a non-uniformity of transmissivity of the varifocal lens in combination with the transmissivity compensation component.

[0024] According to a third aspect of the present disclosure there is provided a method of manufacture, comprising: placing a varifocal lens, wherein a transmissivity of the varifocal lens changes in relation to the optical power of the varifocal lens; disposing a transmissivity compensation component in a same optical path as the varifocal lens, wherein the transmissivity compensation component is configured to change as the optical power of the varifocal lens changes, such that a variation of transmissivity of the varifocal lens is less than a variation of transmissivity of the varifocal lens in combination with the transmissivity compensation component; and communicatively coupling control circuitry to the transmissivity compensation component, the control circuitry configured to transmit a signal to the transmissivity compensation component to change transmissivity as the transmissivity of the varifocal lens changes.

[0025] It will be appreciated that any features described herein as being suitable for incorporation into one or more aspects or embodiments of the present disclosure are intended to be generalizable across any and all aspects and embodiments of the present disclosure. Other aspects of the present disclosure can be understood by those skilled in the art in light of the description, the claims, and the drawings of the present disclosure. The foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings illustrate a number of exemplary embodiments and are a part of the specification. Together with the following description, the drawings demonstrate and explain various principles of the present disclosure.

[0027] FIG. 1 illustrates an example apparatus for Pancharatnam-Berry phase augmented gradient-index liquid crystal lenses according to one or more embodiments of the present disclosure.

[0028] FIG. 2 illustrates an example system for Pancharatnam-Berry phase augmented gradient-index liquid crystal lenses accordingto one or more embodiments of the present disclosure.

[0029] FIG. 3 illustrates another example system for Pancharatnam-Berry phase augmented gradient-index liquid crystal lenses accordingto one or more embodiments of the present disclosure.

[0030] FIGS. 4A and 4B illustrate a pair of optical elements transitioning with complementary transmissivity according to one or more embodiments of the present disclosure.

[0031] FIGS. 5A and 5B illustrate a pair of optical elements transitioning with complementary non-uniform transmissivity according to one or more embodiments of the present disclosure.

[0032] FIG. 6 illustrates a method of manufacture for Pancharatnam-Berry phase augmented gradient-index liquid crystal lenses accordingto one or more embodiments of the present disclosure.

[0033] FIG. 7 is an illustration of exemplary augmented-reality glasses that may be used in connection with one or more embodiments of this disclosure.

[0034] FIG. 8 is an illustration of an exemplary virtual-reality headset that may be used in connection with one or more embodiments of this disclosure.

[0035] Throughout the drawings, identical reference characters and descriptions indicate similar, but not necessarily identical, elements. While the exemplary embodiments described herein are susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. However, the exemplary embodiments described herein are not intended to be limited to the particular forms disclosed. Rather, the present disclosure covers all modifications, equivalents, and alternatives falling within this disclosure.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0036] The present disclosure is generally directed to apparatuses and systems in which Pancharatnam-Berry phase ("PBP") components augment gradient-index liquid crystal ("GRIN LC") lenses. GRIN LC lens designs can allow for dynamically adjustable optical power. However, in these designs, transmittance may vary with optical power. However, for many user experiences it may be important to keep varifocal power independent from brightness. Accordingly, a lens stack design may include a GRIN LC lens and a dimming element. The dimming element may vary in transmittance as the GRIN LC lens varies in optical power, such that the lens stack maintains a constant overall transmittance. The dimming element may be a Pancharatnam-Berry Phase (PBP) lens. In some examples, a larger augmented-reality lens assembly may include the GRIN LC / PBP lens on the world side of a display (e.g., a waveguide), with an accommodative lens on the eye side of the display. The GRIN LC / PBP lens, with lower transmittance, may thereby help to reduce the brightness of the world without negatively impacting the brightness of the AR display, and so improve the function of an AR device outdoors, where the environment may ordinarily be too bright relative to the brightness of the display. The use of the accommodative lens on the eye side of the display along with the GRIN LC / PBP lens on the world side of the display may also mitigate and/or eliminate vergence-accommodation conflict. In addition, because the GRIN LC lens may be placed on the world side of the display, an augmented reality image from the display may not be affected by off-axis aberrations.

[0037] FIG. 1 illustrates an example apparatus 100 for Pancharatnam-Berry phase augmented gradient-index liquid crystal lenses according to some embodiments.

[0038] As shown in FIG. 1, apparatus 100 may include a GRIN LC module 110 and a PBP module 112. In addition, in some examples apparatus 100 may include a control system 120 that transmits one or more signals 122 and/or 124 to GRIN LC module 110 and/or PBP module 112. [0039] Across various optical engineering applications including eyeglasses, contact lenses, and optical elements in augmented reality (AR) and virtual reality (VR) systems, liquid crystal (LC) lenses may provide a number of advantages due to their electrically tunable focusing capability, where the associated optical mechanism is based on a spatially localized modulation of light speed resulting from LC molecular orientations driven by applied electric fields.

[0040] In such context the realization of a continuous distribution of phase retardation across larger aperture (> 10 mm) LC lenses may be challenged by the limited birefringence (< 0.8) of LC materials as well as their mechanically compliant nature. In some embodiments, a gradient-index configuration may be used to provide tunability of focus quality.

[0041] Gradient-index (GRIN) optics refers to a branch of optics where optical effects are produced by a spatial gradient in the refractive index of a material. A gradual refractive index variation may be used to manufacture lenses having planar surfaces, for example, or to reduce aberrations in imaging applications. In an LC lens having an axial gradient configuration, the refractive index may vary along the optical axis of an inhomogeneous medium such that surfaces of constant index are planes that are oriented perpendicular tothe optical axis. In a radial/cylindrical refractive index gradient configuration, on the other hand, the index profile may vary continuously from a centerline of the optical axis to the periphery along the transverse direction in such a way that surfaces of constant index are concentric cylinders located about the optical axis. Hybrid GRIN LC lenses having both an axial and a radial/cylindrical refractive index gradient configuration are also contemplated.

[0042] GRIN-type LC lenses may be configured to exhibit a gradient distribution of refractive index in response to a spatially inhomogeneous electric field that is applied across the LC layer(s). As such, the lens power of a GRIN LC lens may also be continuously tunable. In some instantiations, there may be a continuous variation of the refractive index within the lens material. An LC lens may be configured in both planar and non-planar (e.g., concave or convex) geometries.

[0043] In some examples, adjusting the optical power of a GRIN LC lens may impact the transmissivity of the GRIN LC lens. Thus, for example, adjusting the optical power of the GRIN LC lens may impact the overall transmissivity of the GRIN LC lens. Additionally or alternatively, adjusting the optical power of the GRIN LC lens may impact the transmissivity of the GRIN LC lens non-uniformly over the area of the GRIN LC lens. For example, adjusting the optical power may impact the transmissivity of the GRIN LC lens in radial pattern (e.g., the impact on transmissivity varying in correlation with distance from the center of the GRIN LC lens).

[0044] In view of the foregoing, when control system 120 transmits a signal 122 to GRIN LC lens 110 that alters the optical power of GRIN LC lens 110 (and, thus, the transmissivity of GRIN LC lens 110), a signal may simultaneously alter the transmissivity of PBP module 112. In one example, signal 122 may also be transmitted to PBP module 112, and PBP module 112 may be configured to produce a transmissivity pattern that complements the transmissivity pattern induced by signal 122 in GRIN LC lens 110 to result in a uniform, constant, and/or predetermined transmissivity in (and, e.g., across) apparatus 100. Thus, for example, apparatus 100 may be configured to a predetermined transmissivity of 70%, and PBP module 112 may alter its transmissivity to complement the transmissivity of GRIN LC lens 110 such that the overall transmissivity and/or the location-specific transmissivity of each part of apparatus 100 reaches 70%. In some examples, PBP module 112 may not exactly complement the transmissivity of GRIN LC lens 110, but may instead approximate complementing the transmissivity of GRIN LC lens 110, such that, e.g., the overall transmissivity and/or the location-specific transmissivity of apparatus 100 is more uniform and/or consistent than the transmissivity of GRIN LC lens 110 alone.

[0045] In various examples, the overall transmissivity of apparatus 100 may vary by no more than 1% of a predetermined overall transmissivity, by no more than 2%, by no more than 5%, and/or by no more than 10%. In various examples, the overall transmissivity of apparatus 100 may vary by less than 50% the amount that the transmissivity of GRIN LC lens 110 alone varies, by less than 25%, by less than 10%, and/or by less than 5%. In some examples, at least 80% of the area of apparatus 100 may exhibit less variance in transmissivity than the variance in transmissivity in GRIN LC lens 110, at least 90%, at least 95%, and/or at least 98%. As may be appreciated, in some examples, PBP element 112 may have a uniform transmissivity across its area that changes according to the overall transmissivity of GRIN LC lens 110. In other examples, PBP element 112 may have a non-uniform transmissivity across its area that changes according to the overall transmissivity of GRIN LC lens 110. In some examples, the uniformity of the non-uniform transmissivity of PBP element 112 may change. In other examples, the degree of non-uniformity of the transmissivity of PBP element 112 may stay constant as the overall transmissivity of PBP element 112 changes.

[0046] As noted above, in some examples signal 122 may be transmitted to both GRIN LC lens 110 and PBP element 112. In other examples, signal 122 may be modified before reaching PBP element 112 (e.g., resulting in a signal 124 that reaches PBP element 112). However, signal 124 may be based on signal 122, such that PBP element 112 is responsive to the changes induced in GRIN LC lens 110. In some examples, control system 120 may send separate signals 122 and 124 to GRIN LC lens 110 and PBP element 112, respectively (such that, e.g., signals 122 and 124 result in a reduction in variation of overall transmissivity and/or local transmissivity for apparatus 100 relative to that of GRIN LC lens 110 alone).

[0047] FIG. 2 illustrates an example system 200 for Pancharatnam-Berry phase augmented gradient-index liquid crystal lenses according to some embodiments.

[0048] As shown in FIG. 2, system 200 may include an optical stack 210, a display 212, and apparatus 100 from FIG. 1. Optical stack may be placed on the eye side of display 212, and apparatus 100 may be placed on the world side of display 212. In one example, display 212 may be a virtual image display. In some examples, display 212 may include a waveguide.

[0049] Optical stack 210 may include any suitable elements. In some examples, optical stack 210 may include an accommodation module. The accommodation module may include any suitable optical element with varifocal capabilities. In some examples, the accommodation module may be planar. For example, the accommodation module may be a planar lens, such as a liquid crystal lens. In some examples, the accommodation module may include a liquid lens (e.g., whose shape is changed by one or more actuators). Additionally or alternatively, in some examples optical stack 210 may include an eye tracking module. In some examples, the eye tracking module may be planar. In various examples, the eye tracking module may include one or more waveguides, one or more photodiodes, one or more photonic integrated circuits, one or more illumination elements, and/or one or more cameras. In some examples, the eye tracking module may track a user's gaze and determine, based on the user's gaze, a focal distance of the user's gaze. In some examples, the focal distance determined at least in part by the eye tracking module may drive the accommodation module (and, e.g., apparatus 100). For example, one or more of the systems described herein may modify the optical power of the accommodation module to eliminate the vergence- accommodation conflict as the user views a virtual image shown from display 212. The GRIN LC lens component of apparatus 100 may then compensate for the change in power of the accommodation module such that the image of the world (including, e.g., an image of an object 240) is not effectively altered at eyebox 220 by the accommodation module. However, because the GRIN LC lens component of apparatus 100 may alter the transmissivity of apparatus 100, the PBP element of apparatus 100 may compensate by altering its own transmissivity, to keep the overall transmissivity (and/or the distribution of transmissivity) of apparatus 100 constant (or, e.g., more constant than that of the GRIN LC lens alone).

[0050] FIG. 3 illustrates an example system 300 for Pancharatnam-Berry phase augmented gradient-index liquid crystal lenses according to some embodiments.

[0051] As shown in FIG. 3, system 300 may include illustrates example pancake lens 300 with an embedded accommodation module and an embedded eye tracking module. As shown in FIG. 3, a pancake lens may include a lens 302 and a lens 304. The pancake lens may also include a beamsplitter 314 and a reflective polarizer 312. Additionally, the pancake lens may include an accommodation module 318.

[0052] In addition, the pancake lens may include an eye tracking module 320. In some examples, eye tracking module 320 may be planar. In various examples, eye tracking module 320 may include one or more waveguides, one or more photodiodes, one or more photonic integrated circuits, one or more illumination elements, and/or one or more cameras.

[0053] As illustrated in FIG. 3, in some embodiments eye tracking module 320 may be embedded into lens 304. For example, lens 304 may be divided into two parts and eye tracking module 320 may be positioned between the two parts of lens 304. In one example, eye tracking module 320 may be positioned adjacent to an accommodation module 318, also embedded into lens 304. Eye tracking module 320 may be embedded within lens 304 in any suitable manner. For example, eye tracking module 320 may be laminated to and/or bonded with accommodation module 318, forming a compound module. The compound module containing may be laminated to and/or bonded with parts of lens 304. In some examples, eye tracking module 320 may be connected to a driving circuit (e.g., using flexible cables or other means) that controls and/or actuates the eye tracking capabilities of eye tracking module 320.

[0054] Thus, display 306 may emit an image that reaches eyebox 320, and accommodation module 318 may correct the vergence-accommodation conflict for images produced by display 306 as viewed by a user. In addition, apparatus 100 may compensate for changes in optical power of accommodation module 318 such that, e.g., the image of an object 340 in the world is not modified or distorted. Furthermore, the transmissivity of apparatus 100 may be approximately uniform across its surface and approximately constant over time, even though the transmissivity of the GRIN LC lens component of apparatus 100 may be non-uniform across its surface and/or may change over time.

[0055] FIGS. 4A and 4B illustrate a pair of optical elements transitioning with complementary transmissivity. As shown in FIG. 4A, in a state 402, a varifocal lens 410 may have a relatively high degree of transmissivity. In response, apparatuses and systems described herein may regulate a transmissivity of a component 420 (such as, e.g., a PBP lens) to complement the transmissivity of varifocal lens 410 (e.g., by providing a lower degree of transmissivity). In one example, control circuitry that regulates the optical power (and, therefore, indirectly regulates the transmissivity) of varifocal lens 410 may transmit a control signal to component 420 to regulate the transmissivity of component 420 to be complementary to that of varifocal lens 410 such that varifocal lens 410 and component 420 in tandem provide a predetermined combined target level of transmissivity.

[0056] As shown in FIG. 4B, in a state 404, an optical power of varifocal lens 410 may have changed, thereby impact the transmissivity of varifocal lens 410. For example, the transmissivity of varifocal lens 410 may have decreased. In response, apparatuses and systems described herein may regulate a transmissivity of component 420 to complement the transmissivity of varifocal lens 410 (e.g., by providing a higher degree of transmissivity). In one example, control circuitry that regulates the optical power of varifocal lens 410 may transmit a control signal to component 420 to regulate the transmissivity of component 420 to be complementary to that of varifocal lens 410 such that varifocal lens 410 and component 420 in tandem provide the same predetermined combined target level of transmissivity as was achieved in state 402.

[0057] FIGS. 5A and 5B illustrate a pair of optical elements transitioning with complementary non-uniform transmissivity. As shown in FIG. 5A, in a state 502, a varifocal lens 510 may exhibit a radially decreasing transmissivity. In response, apparatuses and systems described herein may regulate a transmissivity of a component 520 (such as, e.g., a PBP lens) to complement the transmissivity of varifocal lens 510 (e.g., by providing a radially increasing transmissivity). In one example, control circuitry that regulates the optical power (and, therefore, indirectly regulates the transmissivity) of varifocal lens 510 may transmit a control signal to component 520 to regulate the transmissivity of component 520 to be complementary to that of varifocal lens 510 (e.g., both in terms of overall transmissivity and in distribution of transmissivity) such that varifocal lens 510 and component 520 in tandem provide, combined, a substantially uniform and predetermined target level of transmissivity.

[0058] As shown in FIG. 5B, in a state 504, a varifocal lens 510 may exhibit a radially decreasing transmissivity to a lesser degree than in state 502. In response, apparatuses and systems described herein may regulate a transmissivity of a component 520 to complement the transmissivity of varifocal lens 510 (e.g., by providing a transmissivity that radially increases to a lesser degree). In one example, control circuitry that regulates the optical power (and, therefore, indirectly regulates the transmissivity) of varifocal lens 510 may transmit a control signal to component 520 to regulate the transmissivity of component 520 to be complementary to that of varifocal lens 510 (e.g., both in terms of overall transmissivity and in distribution of transmissivity) such that varifocal lens 510 and component 520 in tandem provide, combined, a substantially uniform and predetermined target level of transmissivity.

[0059] FIG. 6 illustrates a method of manufacture 600 for Pancharatnam-Berry phase augmented gradient-index liquid crystal lenses. As shown in FIG. 6, at step 602 method 600 may include placing a varifocal lens, where the transmissivity of the varifocal lens changes in relation to the optical power of the varifocal lens. For example, step 602 may include placing a GRIN LC lens.

[0060] At step 604, method 600 may include disposing a transmissivity compensation component in a same optical path as the varifocal lens, where the transmissivity compensation component is configured to change as the optical power of the varifocal lens changes, such that a variation of transmissivity of the varifocal lens is less than a variation of transmissivity of the varifocal lens in combination with the transmissivity compensation component. For example, step 604 may include coupling a surface of a PBP lens to a surface of the GRIN LC lens.

[0061] At step 606, method 600 may also include communicatively coupling control circuitry to the transmissivity compensation component, the control circuitry being configured to transmit a signal to the transmissivity compensation component to change transmissivity as the transmissivity of the varifocal lens changes. For example, step 606 may include communicatively coupling both the GRIN LC lens and the PBP lens to a control module that regulates the optical power of the GRIN LC lens and the transmissivity of the PBP lens. Additionally or alternatively, step 606 may include communicatively coupling a control module that reads a signal that regulates the optical power of the GRIN LC lens and generating a signal that regulates the PBP lens to produce a complementary level of transmissivity.

[0062] Embodiments of the present disclosure may include or be implemented in conjunction with various types of artificial-reality systems. Artificial reality is a form of reality that has been adjusted in some manner before presentation to a user, which may include, for example, a virtual reality, an augmented reality, a mixed reality, a hybrid reality, or some combination and/or derivative thereof. Artificial-reality content may include completely computer-generated content or computer-generated content combined with captured (e.g., real-world) content. The artificial-reality content may include video, audio, haptic feedback, or some combination thereof, any of which may be presented in a single channel or in multiple channels (such as stereo video that produces a three-dimensional (3D) effect to the viewer). Additionally, in some embodiments, artificial reality may also be associated with applications, products, accessories, services, or some combination thereof, that are used to, for example, create content in an artificial reality and/or are otherwise used in (e.g., to perform activities in) an artificial reality.

[0063] Artificial-reality systems may be implemented in a variety of different form factors and configurations. Some artificial-reality systems may be designed to work without near-eye displays (NEDs). Other artificial-reality systems may include an NED that also provides visibility into the real world (such as, e.g., augmented-reality system 700 in FIG. 7) or that visually immerses a user in an artificial reality (such as, e.g., virtual-reality system 800 in FIG. 8). While some artificial-reality devices may be self-contained systems, other artificialreality devices may communicate and/or coordinate with external devices to provide an artificial-reality experience to a user. Examples of such external devices include handheld controllers, mobile devices, desktop computers, devices worn by a user, devices worn by one or more other users, and/or any other suitable external system.

[0064] Turning to FIG. 7, augmented-reality system 700 may include an eyewear device 702 with a frame 710 configured to hold a left display device 715(A) and a right display device 715(B) in front of a user's eyes. Display devices 715(A) and 715(B) may act together or independently to present an image or series of images to a user. While augmented-reality system 700 includes two displays, embodiments of this disclosure may be implemented in augmented-reality systems with a single NED or more than two NEDs.

[0065] In some embodiments, augmented-reality system 700 may include one or more sensors, such as sensor 740. Sensor 740 may generate measurement signals in response to motion of augmented-reality system 700 and may be located on substantially any portion of frame 710. Sensor 740 may represent one or more of a variety of different sensing mechanisms, such as a position sensor, an inertial measurement unit (IMU), a depth camera assembly, a structured light emitter and/or detector, or any combination thereof. In some embodiments, augmented-reality system 700 may or may not include sensor 740 or may include more than one sensor. In embodiments in which sensor 740 includes an IMU, the IMU may generate calibration data based on measurement signals from sensor 740. Examples of sensor 740 may include, without limitation, accelerometers, gyroscopes, magnetometers, other suitable types of sensors that detect motion, sensors used for error correction of the IMU, or some combination thereof.

[0066] In some examples, augmented-reality system 700 may also include a microphone array with a plurality of acoustic transducers 720(A)-720(J), referred to collectively as acoustic transducers 720. Acoustic transducers 720 may represent transducers that detect air pressure variations induced by sound waves. Each acoustic transducer 720 may be configured to detect sound and convert the detected sound into an electronic format (e.g., an analog or digital format). The microphone array in FIG. 7 may include, for example, ten acoustic transducers: 720(A) and 720(B), which may be designed to be placed inside a corresponding ear of the user, acoustic transducers 720(C), 720(D), 720(E), 720(F), 720(G), and 720(H), which may be positioned at various locations on frame 710, and/or acoustic transducers 720(1) and 720(J), which may be positioned on a corresponding neckband 705.

[0067] In some embodiments, one or more of acoustic transducers 720(A)-(J) may be used as output transducers (e.g., speakers). For example, acoustic transducers 720(A) and/or 720(B) may be earbuds or any other suitable type of headphone or speaker.

[0068] The configuration of acoustic transducers 720 of the microphone array may vary. While augmented-reality system 700 is shown in FIG. 7 as having ten acoustic transducers 720, the number of acoustic transducers 720 may be greater or less than ten. In some embodiments, using higher numbers of acoustic transducers 720 may increase the amount of audio information collected and/or the sensitivity and accuracy of the audio information. In contrast, using a lower number of acoustic transducers 720 may decrease the computing power required by an associated controller 750 to process the collected audio information. In addition, the position of each acoustic transducer720 of the microphone array may vary. For example, the position of an acoustic transducer 720 may include a defined position on the user, a defined coordinate on frame 710, an orientation associated with each acoustic transducer 720, or some combination thereof.

[0069] Acoustic transducers 720(A) and 720(B) may be positioned on different parts of the user's ear, such as behind the pinna, behind the tragus, and/or within the auricle or fossa. Or, there may be additional acoustic transducers 720 on or surrounding the ear in addition to acoustic transducers 720 inside the ear canal. Having an acoustic transducer 720 positioned next to an ear canal of a user may enable the microphone array to collect information on how sounds arrive at the ear canal. By positioning at least two of acoustic transducers 720 on either side of a user's head (e.g., as binaural microphones), augmented- reality device 700 may simulate binaural hearing and capture a 3D stereo sound field around about a user's head. In some embodiments, acoustic transducers 720(A) and 720(B) may be connected to augmented-reality system 700 via a wired connection 730, and in other embodiments acoustic transducers 720(A) and 720(B) may be connected to augmented- reality system 700 via a wireless connection (e.g., a BLUETOOTH connection). In still other embodiments, acoustic transducers 720(A) and 720(B) may not be used at all in conjunction with augmented-reality system 700.

[0070] Acoustic transducers 720 on frame 710 may be positioned in a variety of different ways, including along the length of the temples, across the bridge, above or below display devices 715(A) and 715(B), or some combination thereof. Acoustic transducers 720 may also be oriented such that the microphone array is able to detect sounds in a wide range of directions surrounding the user wearing the augmented-reality system 700. In some embodiments, an optimization process may be performed during manufacturing of augmented-reality system 700 to determine relative positioning of each acoustic transducer 720 in the microphone array.

[0071] In some examples, augmented-reality system 700 may include or be connected to an external device (e.g., a paired device), such as neckband 705. Neckband 705 generally represents any type or form of paired device. Thus, the following discussion of neckband 705 may also apply to various other paired devices, such as charging cases, smart watches, smart phones, wrist bands, other wearable devices, hand-held controllers, tablet computers, laptop computers, other external compute devices, etc.

[0072] As shown, neckband 705 may be coupled to eyewear device 702 via one or more connectors. The connectors may be wired or wireless and may include electrical and/or non-electrical (e.g., structural) components. In some cases, eyewear device 702 and neckband 705 may operate independently without any wired or wireless connection between them. While FIG. 7 illustrates the components of eyewear device 702 and neckband 705 in example locations on eyewear device 702 and neckband 705, the components may be located elsewhere and/or distributed differently on eyewear device 702 and/or neckband 705. In some embodiments, the components of eyewear device 702 and neckband 705 may be located on one or more additional peripheral devices paired with eyewear device 702, neckband 705, or some combination thereof.

[0073] Pairing external devices, such as neckband 705, with augmented-reality eyewear devices may enable the eyewear devices to achieve the form factor of a pair of glasses while still providing sufficient battery and computation power for expanded capabilities. Some or all of the battery power, computational resources, and/or additional features of augmented-reality system 700 may be provided by a paired device or shared between a paired device and an eyewear device, thus reducing the weight, heat profile, and form factor of the eyewear device overall while still retaining desired functionality. For example, neckband 705 may allow components that would otherwise be included on an eyewear device to be included in neckband 705 since users may tolerate a heavier weight load on their shoulders than they would tolerate on their heads. Neckband 705 may also have a larger surface area over which to diffuse and disperse heat to the ambient environment. Thus, neckband 705 may allow for greater battery and computation capacity than might otherwise have been possible on a stand-alone eyewear device. Since weight carried in neckband 705 may be less invasive to a user than weight carried in eyewear device 702, a user may tolerate wearing a lighter eyewear device and carrying or wearing the paired device for greater lengths of time than a user would tolerate wearing a heavy standalone eyewear device, thereby enabling users to more fully incorporate artificial-reality environments into their day-to-day activities.

[0074] Neckband 705 may be communicatively coupled with eyewear device 702 and/or to other devices. These other devices may provide certain functions (e.g., tracking, localizing, depth mapping, processing, storage, etc.) to augmented-reality system 700. In the embodiment of FIG. 7 , neckband 705 may include two acoustic transducers (e.g., 720(1) and 720(J)) that are part of the microphone array (or potentially form their own microphone subarray). Neckband 705 may also include a controller 725 and a power source 735.

[0075] Acoustic transducers 720(1) and 720(J) of neckband 705 may be configured to detect sound and convert the detected sound into an electronic format (analog or digital). In the embodiment of FIG. 7 , acoustic transducers 720(1) and 720(J) may be positioned on neckband 705, thereby increasing the distance between the neckband acoustic transducers 720(1) and 720(1) and other acoustic transducers 720 positioned on eyewear device 702. In some cases, increasing the distance between acoustic transducers 720 of the microphone array may improve the accuracy of beamforming performed via the microphone array. For example, if a sound is detected by acoustic transducers 720(C) and 720(D) and the distance between acoustic transducers 720(C) and 720(D) is greater than, e.g., the distance between acoustic transducers 720(D) and 720(E), the determined source location of the detected sound may be more accurate than if the sound had been detected by acoustic transducers 720(D) and 720(E).

[0076] Controller 725 of neckband 705 may process information generated by the sensors on neckband 705 and/or augmented-reality system 700. For example, controller 725 may process information from the microphone array that describes sounds detected by the microphone array. Foreach detected sound, controller 725 may perform a direction-of-arrival (DOA) estimation to estimate a direction from which the detected sound arrived at the microphone array. As the microphone array detects sounds, controller 725 may populate an audio data set with the information. In embodiments in which augmented-reality system 700 includes an inertial measurement unit, controller 725 may compute all inertial and spatial calculations from the IMU located on eyewear device 702. A connector may convey information between augmented-reality system 700 and neckband 705 and between augmented-reality system 700 and controller 725. The information may be in the form of optical data, electrical data, wireless data, or any other transmittable data form. Moving the processing of information generated by augmented-reality system 700 to neckband 705 may reduce weight and heat in eyewear device 702, making it more comfortable to the user.

[0077] Power source 735 in neckband 705 may provide power to eyewear device 702 and/or to neckband 705. Power source 735 may include, without limitation, lithium ion batteries, lithium-polymer batteries, primary lithium batteries, alkaline batteries, or any other form of power storage. In some cases, power source 735 may be a wired power source. Including power source 735 on neckband 705 instead of on eyewear device 702 may help better distribute the weight and heat generated by power source 735.

[0078] As noted, some artificial-reality systems may, instead of blending an artificial reality with actual reality, substantially replace one or more of a user's sensory perceptions of the real world with a virtual experience. One example of this type of system is a head-worn display system, such as virtual-reality system 800 in FIG. 8, that mostly or completely covers a user's field of view. Virtual-reality system 800 may include a front rigid body 802 and a band 804 shaped to fit around a user's head. Virtual-reality system 800 may also include output audio transducers 806(A) and 806(B). Furthermore, while not shown in FIG. 8, front rigid body 802 may include one or more electronic elements, including one or more electronic displays, one or more inertial measurement units (IMUs), one or more tracking emitters or detectors, and/or any other suitable device or system for creating an artificial-reality experience.

[0079] Artificial-reality systems may include a variety of types of visual feedback mechanisms. For example, display devices in augmented-reality system 700 and/or virtual- reality system 800 may include one or more liquid crystal displays (LCDs), light emitting diode (LED) displays, microLED displays, organic LED (OLED) displays, digital light project (DLP) micro-displays, liquid crystal on silicon (LCoS) micro-displays, and/or any other suitable type of display screen. These artificial-reality systems may include a single display screen for both eyes or may provide a display screen for each eye, which may allow for additional flexibility for varifocal adjustments or for correcting a user's refractive error. Some of these artificial-reality systems may also include optical subsystems having one or more lenses (e.g., concave or convex lenses, Fresnel lenses, adjustable liquid lenses, etc.) through which a user may view a display screen. These optical subsystems may serve a variety of purposes, including to collimate (e.g., make an object appear at a greater distance than its physical distance), to magnify (e.g., make an object appear larger than its actual size), and/or to relay (to, e.g., the viewer's eyes) light. These optical subsystems may be used in a non-pupil- forming architecture (such as a single lens configuration that directly collimates light but results in so-called pincushion distortion) and/or a pupil-forming architecture (such as a multilens configuration that produces so-called barrel distortion to nullify pincushion distortion).

[0080] In addition to or instead of using display screens, some of the artificial-reality systems described herein may include one or more projection systems. For example, display devices in augmented-reality system 700 and/or virtual-reality system 800 may include micro-LED projectors that project light (using, e.g., a waveguide) into display devices, such as clear combiner lenses that allow ambient light to pass through. The display devices may refract the projected light toward a user's pupil and may enable a user to simultaneously view both artificial-reality content and the real world. The display devices may accomplish this using any of a variety of different optical components, including waveguide components (e.g., holographic, planar, diffractive, polarized, and/or reflective waveguide elements), light-manipulation surfaces and elements (such as diffractive, reflective, and refractive elements and gratings), coupling elements, etc. Artificial-reality systems may also be configured with any other suitable type or form of image projection system, such as retinal projectors used in virtual retina displays.

[0081] The artificial-reality systems described herein may also include various types of computer vision components and subsystems. For example, augmented-reality system 700 and/or virtual-reality system 800 may include one or more optical sensors, such as two-dimensional (2D) or 3D cameras, structured light transmitters and detectors, time-of- flight depth sensors, single-beam or sweeping laser rangefinders, 3D LiDAR sensors, and/or any other suitable type or form of optical sensor. An artificial-reality system may process data from one or more of these sensors to identify a location of a user, to map the real world, to provide a user with context about real-world surroundings, and/or to perform a variety of other functions.

[0082] The artificial-reality systems described herein may also include one or more input and/or output audio transducers. Output audio transducers may include voice coil speakers, ribbon speakers, electrostatic speakers, piezoelectric speakers, bone conduction transducers, cartilage conduction transducers, tragus-vibration transducers, and/or any other suitable type or form of audio transducer. Similarly, input audio transducers may include condenser microphones, dynamic microphones, ribbon microphones, and/or any other type or form of input transducer. In some embodiments, a single transducer may be used for both audio input and audio output.

[0083] In some embodiments, the artificial-reality systems described herein may also include tactile (i.e., haptic) feedback systems, which may be incorporated into headwear, gloves, body suits, handheld controllers, environmental devices (e.g., chairs, floormats, etc.), and/or any other type of device or system. Haptic feedback systems may provide various types of cutaneous feedback, including vibration, force, traction, texture, and/or temperature. Haptic feedback systems may also provide various types of kinesthetic feedback, such as motion and compliance. Haptic feedback may be implemented using motors, piezoelectric actuators, fluidic systems, and/or a variety of other types of feedback mechanisms. Haptic feedback systems may be implemented independent of other artificial-reality devices, within other artificial-reality devices, and/or in conjunction with other artificial-reality devices.

[0084] By providing haptic sensations, audible content, and/or visual content, artificial-reality systems may create an entire virtual experience or enhance a user's real- world experience in a variety of contexts and environments. For instance, artificial-reality systems may assist or extend a user's perception, memory, or cognition within a particular environment. Some systems may enhance a user's interactions with other people in the real world or may enable more immersive interactions with other people in a virtual world. Artificial-reality systems may also be used for educational purposes (e.g., for teaching or training in schools, hospitals, government organizations, military organizations, business enterprises, etc.), entertainment purposes (e.g., for playing video games, listening to music, watching video content, etc.), and/or for accessibility purposes (e.g., as hearing aids, visual aids, etc.). The embodiments disclosed herein may enable or enhance a user's artificial-reality experience in one or more of these contexts and environments and/or in other contexts and environments.

[0085] The process parameters and sequence of the steps described and/or illustrated herein are given by way of example only and can be varied as desired. For example, while the steps illustrated and/or described herein may be shown or discussed in a particular order, these steps do not necessarily need to be performed in the order illustrated or discussed. The various exemplary methods described and/or illustrated herein may also omit one or more of the steps described or illustrated herein or include additional steps in addition to those disclosed.

[0086] The preceding description has been provided to enable others skilled in the art to best utilize various aspects of the exemplary embodiments disclosed herein. This exemplary description is not intended to be exhaustive or to be limited to any precise form disclosed. Many modifications and variations are possible without departing from the scope of the present disclosure. The embodiments disclosed herein should be considered in all respects illustrative and not restrictive. Reference should be made to any claims appended hereto and their equivalents in determining the scope of the present disclosure.

[0087] Uni ess otherwise noted, the terms "connected to" and "coupled to" (and their derivatives), as used in the specification and/or claims, are to be construed as permitting both direct and indirect (i.e., via other elements or components) connection. In addition, the terms "a" or "an," as used in the specification and/or claims, are to be construed as meaning "at least one of." Finally, for ease of use, the terms "including" and "having" (and their derivatives), as used in the specification and/or claims, are interchangeable with and have the same meaning as the word "comprising."

Claims

WHAT IS CLAIMED IS:

1. An apparatus comprising: a varifocal lens, wherein the transmissivity of the varifocal lens changes in relation to the optical power of the varifocal lens; and a transmissivity compensation component that is configured to change as the optical power of the varifocal lens changes, such that a variation of transmissivity of the varifocal lens is less than a variation of transmissivity of the varifocal lens in combination with the transmissivity compensation component.

2. The apparatus of claim 1, wherein: the varifocal lens is planar; and the transmissivity compensation component is planar.

3. The apparatus of claim 1 or 2, wherein the varifocal lens comprises a gradientindex liquid crystal lens; and/or the transmissivity compensation component comprises a Pancharatnam-Berry phase element.

4. The apparatus of any one of the preceding claims, further comprising control circuitry that transmits a signal to the transmissivity compensation component that regulates a transmissivity of the transmissivity compensation component; preferably wherein the control circuitry generates the signal based at least in part on at least one of: a signal received by the control circuitry to change an optical power of the varifocal lens; a signal received by the control circuitry indicating a change to the optical power of the varifocal lens; or a signal received by the control circuitry indicating a change to a transmissivity of the varifocal lens.

5. The apparatus of any one of the preceding claims, wherein a change in the transmissivity of the varifocal lens in relation to the optical power of the varifocal lens is non- uniform across the varifocal lens; preferably wherein the transmissivity compensation component is configured to change as the optical power of the varifocal lens changes such that a non-uniformity of transmissivity of the varifocal lens is less than a non-uniformity of transmissivity of the varifocal lens in combination with the transmissivity compensation component.

6. The apparatus of any one of the preceding claims, wherein a change in the transmissivity of the varifocal lens in relation to the optical power of the varifocal lens varies radially across the varifocal lens; preferably wherein the transmissivity compensation component is configured to change with a radial distribution across the transmissivity compensation component as the optical power of the varifocal lens changes.

7. A system comprising: a lens apparatus, comprising: a varifocal lens, wherein the transmissivity of the varifocal lens changes in relation to the optical power of the varifocal lens; and a transmissivity compensation component that is configured to change as the optical power of the varifocal lens changes, such that a variation of transmissivity of the varifocal lens is less than a variation of transmissivity of the varifocal lens in combination with the transmissivity compensation component; an accommodation module; and a head-mounted display.

8. The system of claim 7, wherein the head-mounted display comprises a virtual image display.

9. The system of claim 8, wherein: the accommodation module is on an eye side of the display; and the varifocal lens and the transmissivity compensation component are on a world side of the display.

10. The system of any one of claims 7 to 9, wherein the varifocal lens comprises a gradient-index liquid crystal lens.

11. The system of any one of claims 7 to 10, wherein the transmissivity compensation component comprises a Pancharatnam-Berry phase element.

12. The system of any one of claims 7 to 11, further comprising control circuitry that transmits a signal to the transmissivity compensation component that regulates a transmissivity of the transmissivity compensation component; preferably wherein the control circuitry generates the signal based at least in part on at least one of: a signal received by the control circuitry to change an optical power of the varifocal lens; a signal received by the control circuitry indicating a change to the optical power of the varifocal lens; or a signal received by the control circuitry indicating a change to a transmissivity of the varifocal lens.

13. The system of any one of claims 7 to 12, wherein a change in a transmissivity of the varifocal lens in relation to the optical power of the varifocal lens is non-uniform across the varifocal lens.

14. The system of any one of claims 7 to 13, wherein the transmissivity compensation component is configured to change as the optical power of the varifocal lens changes such that a non-uniformity of transmissivity of the varifocal lens is less than a nonuniformity of transmissivity of the varifocal lens in combination with the transmissivity compensation component.

15. A method of manufacture, comprising: placing a varifocal lens, wherein a transmissivity of the varifocal lens changes in relation to the optical power of the varifocal lens; disposing a transmissivity compensation component in a same optical path as the varifocal lens, wherein the transmissivity compensation component is configured to change as the optical power of the varifocal lens changes, such that a variation of transmissivity of the varifocal lens is less than a variation of transmissivity of the varifocal lens in combination with the transmissivity compensation component; and communicatively coupling control circuitry to the transmissivity compensation component, the control circuitry configured to transmit a signal to the transmissivity compensation component to change transmissivity as the transmissivity of the varifocal lens changes.