CN117784493A - Stacked graded index liquid crystal lens assembly - Google Patents

Abstract

The disclosed apparatus may include a lens stack. The lens stack may include a first graded index liquid crystal lens and a second graded index liquid crystal lens mated with the first graded index liquid crystal lens. The lens stack may be configured to reach a target optical power based on the first optical power of the first graded index liquid crystal lens and the second optical power of the second graded index liquid crystal lens. Various other devices, systems, and methods are also disclosed.

Description

Stacked graded index liquid crystal lens assembly

Cross Reference to Related Applications

The present application claims the benefit of U.S. provisional application No. 63/377,575, filed on 9.29 of 2022, and U.S. application No. 18/171,964, filed on 21 of 2023, the disclosures of which are incorporated herein by reference in their entirety.

Technical Field

The present invention relates to the field of lenses, and in particular to a stacked graded-index (GRIN) Liquid Crystal (LC) lens assembly.

Background

In a variety of optical engineering applications including lenses, contact lenses and optical elements in augmented Reality (Augmented Reality, AR) systems and Virtual Reality (VR) systems, liquid Crystal (LC) lenses may offer a number of advantages due to their electrically tunable focusing capabilities, where the associated optical mechanisms are based on spatially localized modulation of the speed of light resulting from the orientation of LC molecules driven by an applied electric field.

Disclosure of Invention

In one embodiment of the present invention, an apparatus is provided that includes a lens stack including: a first graded index liquid crystal lens; and a second graded index liquid crystal lens mated with the first graded index liquid crystal lens, wherein the lens stack is configured to reach a target optical power based on a first optical power of the first graded index liquid crystal lens and a second optical power of the second graded index liquid crystal lens.

In another embodiment of the present invention, a system is provided that includes a head mounted display including a lens stack including: a first graded index liquid crystal lens; and a second graded index liquid crystal lens mated with the first graded index liquid crystal lens, wherein the lens stack is configured to reach a target optical power based on a first optical power of the first graded index liquid crystal lens and a second optical power of the second graded index liquid crystal lens.

In yet another embodiment of the present invention, a method of manufacturing is provided that includes assembling a lens stack by: setting a first graded index liquid crystal lens; and providing a second graded index liquid crystal lens that mates with the first graded index liquid crystal lens, wherein the lens stack is configured to reach a target optical power based on a first optical power of the first graded index liquid crystal lens and a second optical power of the second graded index liquid crystal lens.

Drawings

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

Fig. 1 illustrates an outline of an optical path difference (optical path difference) in an example GRIN LC lens architecture, according to some embodiments.

Fig. 2 illustrates example liquid crystal regions in a GRIN LC lens design according to some embodiments.

Fig. 3 illustrates example scattering regions in a GRIN LC lens design, according to some embodiments.

FIG. 4 illustrates an example mask pattern for an example GRIN LC lens design, in accordance with certain embodiments.

FIG. 5 illustrates an example mask pattern for an example stacked plurality of GRIN LC lenses, in accordance with certain embodiments.

Fig. 6 illustrates an example GRIN LC lens stack, according to some embodiments.

Fig. 7 illustrates an example GRIN LC lens stack, according to some embodiments.

Fig. 8 illustrates an example GRIN LC lens stack, according to some embodiments.

Fig. 9 is an illustration of exemplary augmented reality glasses that may be used in connection with embodiments of the present disclosure.

Fig. 10 is an illustration of an exemplary virtual reality headset (head set) that may be used in connection with embodiments of the present disclosure.

Throughout the drawings, identical reference numbers 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. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the appended claims.

Detailed Description

In a variety of optical engineering applications including lenses, contact lenses and optical elements in augmented Reality (Augmented Reality, AR) systems and Virtual Reality (VR) systems, liquid Crystal (LC) lenses may offer a number of advantages due to their electrically tunable focusing capabilities, where the associated optical mechanisms are based on spatially localized modulation of the speed of light resulting from the orientation of LC molecules driven by an applied electric field.

In this case, achieving a continuous phase retardation distribution over a large aperture (> 10 mm) LC lens may be challenged by the finite birefringence (< 0.5) of the LC materials and the mechanically compliant nature of these LC materials. In some embodiments, graded index configurations may be used to provide adjustability of focus quality.

Graded index (GRIN) optics refers to branches of optics in which optical effects are produced by spatial grading of the refractive index of the material. For example, graded index changes may be used to fabricate lenses with flat surfaces, or to reduce aberrations in imaging applications. In LC lenses with axially graded construction, the refractive index may vary along the optical axis of the non-uniform medium, such that the surface of constant refractive index is a plane oriented perpendicular to the optical axis. On the other hand, in the radial/cylindrical refractive index gradient configuration, the refractive index profile (profile) may continuously vary in the lateral direction from the center line of the optical axis to the periphery in such a manner that the surface of the constant refractive index is a concentric cylinder located around the optical axis. Hybrid GRIN LC lenses having both axial and radial/cylindrical graded index configurations are also contemplated.

The GRIN LC lens may be configured to exhibit a graded distribution of refractive index in response to a spatially non-uniform electric field applied across one or more LC layers. As such, the lens power (lens power) of the GRIN LC lens may also be continuously adjustable. In some examples, there may be a continuous change in refractive index within the lens material. LC lenses may be configured in planar geometry and non-planar (e.g., concave or convex) geometry.

In some examples, the tunable architecture may include a voltage tunable layer formed over one or more LC layers within an optical aperture of a lens. During operation, different voltages may be applied to different regions of the voltage tunable layer, which may be used to locally adjust the refractive index of the LC material. The voltage tunable layer may have any suitable design. For example, the voltage tunable layer may include a plurality of discrete ring electrodes formed over one or more LC layers within the optical aperture of the lens. During operation, different voltages may be applied to the respective electrodes, which may be used to locally adjust the refractive index of the LC material.

In some examples, the lens may have a fresnel structure, where a phase reset (phase reset) boundary may correspond to an abrupt change in voltage. Abrupt changes in voltage may create fringing fields that may cause the liquid crystal near the phase reset boundary to twist (e.g., away from normal alignment and/or away from alignment that produces undesirable optical effects). In some examples, crystal twisting at the phase reset boundary may cause performance defects, including the generation of optical artifacts such as scattering.

As used herein, the terms "scattering" and "sharpness" may refer to optical phenomena associated with the transmittance of light through a medium. As will be appreciated, scattering may be associated with an amount of light that experiences wide angle scattering (e.g., angles greater than 2.5 ° from normal) and a corresponding loss of transmission contrast, while sharpness may be associated with an amount of light that experiences narrow angle scattering (e.g., angles less than 2.5 ° from normal) and a concomitant loss of optical sharpness.

In some examples, to reduce scattering, the lens may include a mask that blocks light at and around the phase reset boundary (e.g., blocks areas through which scattered light would otherwise pass). However, the cost of doing so may reduce the transmissivity of the lens.

The power of GRIN-type LC lenses may increase with increasing thickness, but at the cost of slower response time, reduced viewing angle, and more reset area. By using two GRIN-type LC lenses in combination, the same optical power can be obtained without the drawbacks of thicker GRIN-type LC lenses. However, the use of two GRIN-type LC lenses may result in angular separation of the masking regions in the respective GRIN-type LC lenses. Such parallax may disproportionately negatively affect the transmittance through certain regions of the lens stack. However, as will be described in more detail herein, by using two GRIN-type LC lenses with different masking positions, the masking regions can be made to coincide with each other (in-line) from a particular view angle. In some examples, this may be achieved by dividing the optical power unevenly between the two GRIN-type LC lenses (as this may cause the spacing between the masking regions of the lenses to be different). Further, by bringing the liquid crystal components of the GRIN LC lens closer together, parallax can be further reduced. In some examples, the GRIN-type LC lens stack may have two GRIN-type LC lenses sharing the substrate (with the added benefit of making the assembly thinner) and/or by inverting one of the GRIN LC lenses so that the liquid crystal sides of the GRIN LC lenses are adjacent to each other.

In some examples, two GRIN LC lenses may each have zoom capability. The zoom capability may involve changing the fresnel reset pattern of the GRIN LC lens and thus may involve dynamically changing the mask pattern of the GRIN LC lens. Thus, various combinations of the optical powers of the two GRIN LC lenses may function to achieve a target optical power when the optical powers of the lens stack are adjusted as a whole. Thus, in some examples, the systems described herein may select a combination of two GRIN LC lens powers that achieves both (1) a target cumulative optical power and (2) a combination of mask patterns that reduces occlusion of the mask to a preferred viewing angle when parallax between the lenses is considered from the preferred viewing angle. These systems may determine the preferred viewing angle in any of a variety of ways. For example, these systems may determine a preferred viewing angle based on a current viewing angle of the user (e.g., a viewing angle as determined by the eye tracking device). Additionally or alternatively, the systems may determine the preferred viewing angle based on metadata describing one or more regions of interest in the image projected through the lens.

Fig. 1 illustrates a profile 100 of optical path differences in an example GRIN LC lens architecture, according to some embodiments. The GRIN LC lens architecture may include a fresnel structure. Thus, as shown in FIG. 1, profile 100 may include several Fresnel resets. The density of fresnel resets may increase toward the periphery of the lens.

Fig. 2 illustrates an example liquid crystal region 200 in a GRIN LC lens design in accordance with some embodiments. As shown in fig. 2, the liquid crystals in the phase region 202, starting at the leftmost column, may be arranged (e.g., via an applied voltage) to be aligned longitudinally along the z-axis. In each subsequent column of the phase region 202, the liquid crystal may further rotate in the y-z plane until the liquid crystal is aligned longitudinally along the y-axis. In the case of a phase reset after the phase region 202, a similar pattern may be repeated in the phase region 204. However, as can be appreciated, in the phase reset boundary region 210, the liquid crystal may deviate from the pattern. For example, rather than fully aligning one column longitudinally along the y-axis before reset and then fully aligning the next column longitudinally along the z-axis after reset, the liquid crystal in phase reset boundary region 210 may twist (e.g., include rotation in the x-y plane).

In some examples, the twisting of the liquid crystal in phase reset boundary region 210 may be due, at least in part, to fringing fields generated by abrupt changes in voltage at the phase reset boundary between phase regions 202 and 204.

Fig. 3 shows an example GRIN LC lens 300. As shown in fig. 3, one or more light rays 310 (e.g., as part of a plane wave) may enter the lens 300. Due to the optical properties of the lens 300, one or more deflected light rays 312 may emerge from the other side of the lens 300. However, in the phase reset transition region 320, fringe fields may cause the exiting light 322 to scatter. Light ray 322 may result in scattering and/or reduced sharpness. In some examples, the mask 330 may be positioned to block at least some of the scattered light 322. However, mask 330 may reduce the transmissivity of lens 300 (e.g., by blocking some of deflected light rays 312).

Fig. 4 shows an example mask pattern 400 for an example GRIN LC lens design. As shown in fig. 4, the mask pattern 400 may block some light, thus reducing the transmittance of the GRIN LC lens.

Fig. 5 illustrates an example mask pattern 500 for an example stacked plurality of GRIN LC lenses, in accordance with certain embodiments. In one example, the stacked plurality of GRIN LC lenses may have the same optical power and thus the same mask pattern. However, since one lens is at a distance behind the other lens, the mask pattern may exhibit parallax from the viewing position. This parallax may cause the mask of one GRIN LC lens to block light in the unmasked areas of the other GRIN LC lens, reducing overall transmittance to a greater extent than the single lens mask pattern 400 shown in fig. 4, and reducing localized transmittance in certain areas (including, for example, the periphery) disproportionately.

Fig. 6 illustrates an example GRIN LC lens stack 600, according to some embodiments. As shown in fig. 6, GRIN LC lens stack 600 may include two GRIN LC lenses (e.g., GRIN LC lens 602 and GRIN LC lens 604) mated. The two GRIN LC lenses 602 and 604 in combination may provide a cumulative optical power. Furthermore, because each GRIN LC lens is thinner than a single GRIN LC lens having the same optical power, the response time and viewing angle of stack 600 may be faster and wider than a single LC lens having the same optical power would have.

Furthermore, the two GRIN LC lenses 602 and 604 of stack 600 may have different optical powers from each other, each contributing a different ratio to the cumulative optical power of stack 600. The different powers of the two GRIN LC lenses may correspond to different fresnel reset patterns and thus to different mask patterns. Different mask patterns may result in a larger alignment of the mask pattern (given parallax) at certain viewing angles. Thus, for example, given a particular mask pattern for each lens, the view cone 610 may not be obscured by the masks of the two lenses.

In some examples, the two GRIN LC lenses 602 and 604 may be selected such that they cooperate to produce a target optical power. Additionally or alternatively, the two GRIN LC lenses 602 and 604 may be zoom lenses and may be dynamically configured and/or adjusted such that they cooperate to produce a target optical power.

As shown in fig. 6, in one example, GRIN LC lens 602 may include a substrate 622, a substrate 626, a set of masks 628, a liquid crystal layer 630, a gasket (gasset) 632, a substrate 634, a conductive layer 636, a substrate 638, a conductor 640, a conductive layer 642, and a substrate 644.

Substrate 622 may comprise any suitable optically transparent substrate. For example, the substrate 622 may include glass, silicon dioxide, and/or an optically transparent polymer. Substrate 626 may comprise any suitable optically transparent substrate. For example, substrate 626 may include glass and/or optically transparent polymers. In one example, the substrate 626 may comprise polyimide (e.g., optically transparent polyimide). Mask 628 may include any suitable dye material and/or optically absorbing material. In some examples, the pattern of mask 628 may be changeable (e.g., via an electrical signal). Thus, in these examples, substrate 626 and mask 628 together may form any suitable optically transparent layer in addition to the changeable pattern of opaque elements.

The conductive layer 636 may comprise any suitable conductive material. For example, the conductive layer 636 may include an optically transparent conductive material. In some examples, the conductive layer 636 may include indium tin oxide. Substrate 638 may comprise any suitable material. For example, the substrate 638 may include silicon dioxide. Conductor 640 may comprise any suitable material. For example, conductor 640 may include nickel. The substrate 644 may comprise any suitable material. For example, the substrate 644 may include glass, silicon dioxide, and/or an optically transparent polymer.

In some examples, GRIN LC lens 604 may have a substantially similar design as GRIN LC lens 602. However, in some examples, a set of masks 658 in lens 604 may have a different mask pattern than mask 628 in lens 602. For example, mask 658 may be spaced wider than mask 628 such that one or more cones (e.g., cone 610) may be partially or completely unobstructed by the masks of both lenses 602 and 604.

Fig. 7 illustrates an example GRIN LC lens stack 700, according to some embodiments. As shown in fig. 7, stack 700 may include mated GRIN LC lens 702 and GRIN LC lens 704.GRIN LC lenses 702 and 704 may share a substrate 710 (e.g., a glass substrate). This may enable stack 700 to be thinner than would otherwise be the case (e.g., thinner than stack 600 in fig. 6). Furthermore, the mask layer of GRIN LC lens 702 and the mask layer of GRIN LC lens 704 may be more closely together, potentially reducing the overall parallax effect between the mask patterns of the two GRIN LC lenses.

Fig. 8 illustrates an example GRIN LC lens stack 800, according to some embodiments. As shown in fig. 8, stack 800 may include mating GRIN LC lens 802 and GRIN LC lens 804. GRIN LC lenses 802 and 804 of stack 800 may share a substrate. Furthermore, one of the GRIN LC lenses may be inverted relative to the other GRIN LC lens (e.g., lens 802 may be inverted relative to lens 804) such that the mask layer of GRIN LC lens 802 and the mask layer of GRIN LC lens 804 may be more closely together, thereby reducing the overall parallax effect between the mask patterns of the two GRIN LC lenses.

As will be explained in more detail below, in some examples, one or more lens stacks described herein may be incorporated into a head-mounted display (e.g., VR system and/or AR system).

Example embodiment

Example 1: an apparatus may include a lens stack. The lens stack includes: a first graded index liquid crystal lens; and a second graded index liquid crystal lens, the second graded index liquid crystal lens being mated with the first graded index liquid crystal lens. The lens stack may be configured to reach a target optical power based on the first optical power of the first graded index liquid crystal lens and the second optical power of the second graded index liquid crystal lens.

Example 2: the apparatus of example 1, wherein the first GRIN LC lens and the second GRIN LC lens are zoom lenses.

Example 3: the apparatus of any one of examples 1 and 2, wherein the first GRIN LC lens comprises a first layer mask located at one or more fresnel resets of the first graded index LC lens; and the second graded index liquid crystal lens includes a second layer mask located at one or more fresnel resets of the second graded index liquid crystal lens.

Example 4: the apparatus of any of examples 1 to 3, wherein the first optical power is different from the second optical power.

Example 5: the apparatus according to any one of examples 1 to 4, wherein when the first optical power of the first GRIN LC lens is changed, the second optical power of the second GRIN LC lens is changed such that the first GRIN LC lens and the second GRIN LC lens maintain different optical powers.

Example 6: the apparatus of any of examples 1-5, wherein the first GRIN LC lens comprises a first layer mask and the second GRIN LC lens comprises a second layer mask.

Example 7: the apparatus of any one of examples 1 to 6, wherein the first layer mask blocks light scattered by the first GRIN LC lens and the second layer mask blocks light scattered by the second GRIN LC lens.

Example 8: the apparatus of any one of examples 1 to 7, wherein the first layer mask is aligned with one or more fresnel resets of the first GRIN LC lens and the second layer mask is aligned with one or more fresnel resets of the second GRIN LC lens.

Example 9: the apparatus according to any one of examples 1 to 8, wherein the first GRIN LC lens and the second GRIN LC lens are arranged such that the first layer mask and the second layer mask are positioned between a first liquid crystal layer of the first GRIN LC lens and a second liquid crystal layer of the second GRIN LC lens.

Example 10: the apparatus of any one of examples 1 to 9, wherein the first GRIN LC lens and the second GRIN LC lens share a substrate.

Embodiments of the present disclosure may include or be implemented in conjunction with various types of artificial reality systems. An artificial reality is a form of reality that is somehow adjusted before being presented to a user, and may include, for example, virtual reality, augmented reality, mixed reality (mixed reality), mixed reality (hybrid reality), or some combination and/or derivative thereof. The artificial reality content may include entirely computer-generated content or computer-generated content combined with collected (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 multiple channels (e.g., stereoscopic video that produces a three-dimensional (3D) effect to a viewer). Further, in some embodiments, the artificial reality may also be associated with an application, product, accessory, service, or some combination thereof, for example, to create content in the artificial reality and/or otherwise use in the artificial reality (e.g., perform an activity in the artificial reality).

The artificial reality system may be implemented in a variety of different form factors and configurations. Some artificial reality systems may be designed to operate without a Near-eye Display (NED). Other artificial reality systems may include NEDs that also provide visibility to the real world (e.g., such as the augmented reality system 900 in FIG. 9) or NEDs that visually immerse the user in artificial reality (e.g., such as the virtual reality system 1000 in FIG. 10). While some artificial reality devices may be stand-alone systems, other artificial reality devices may communicate and/or coordinate with external devices to provide an artificial reality experience to a user. Examples of such external devices include a handheld controller, a mobile device, a desktop computer, a device worn by a user, one or more other devices worn by a user, and/or any other suitable external system.

Turning to fig. 9, the augmented reality system 900 may include an eyeglass device 902 having a frame 910 configured to hold a left display device 915 (a) and a right display device 915 (B) in front of both eyes of a user. The display devices 915 (a) and 915 (B) may operate together or independently to present an image or series of images to a user. Although the augmented reality system 900 includes two displays, embodiments of the present disclosure may be implemented in an augmented reality system having a single NED or more than two nes.

In some embodiments, the augmented reality system 900 may include one or more sensors, such as sensor 940. The sensor 940 may generate measurement signals in response to movement of the augmented reality system 900 and may be located on substantially any portion of the frame 910. The sensor 940 may represent one or more of a variety of different sensing mechanisms, such as a position sensor, an inertial measurement unit (Inertial Measurement Unit, IMU), a depth camera assembly, a structured light emitter and/or detector, or any combination thereof. In some embodiments, the augmented reality system 900 may or may not include a sensor 940, or may include more than one sensor. In embodiments where the sensor 940 includes an IMU, the IMU may generate calibration data based on measurement signals from the sensor 940. Examples of sensors 940 may include, but are not limited to, accelerometers, gyroscopes, magnetometers, other suitable types of sensors that detect motion, sensors for IMU error correction, or some combination thereof.

In some examples, the augmented reality system 900 may also include a microphone array having a plurality of acoustic transducers 920 (a) through 920 (J), collectively referred to as acoustic transducers 920. The acoustic transducer 920 may represent a transducer that detects changes in air pressure caused by sound waves. Each acoustic transducer 920 may be configured to detect sound and convert the detected sound into an electronic format (e.g., analog format or digital format). The microphone array in fig. 9 may comprise, for example, ten acoustic transducers: acoustic transducer 920 (a) and acoustic transducer 920 (B), which may be designed to be placed within respective ears of a user; acoustic transducer 920 (C), acoustic transducer 920 (D), acoustic transducer 920 (E), acoustic transducer 920 (F), acoustic transducer 920 (G), and acoustic transducer 920 (H), which may be positioned at different locations on frame 910; and/or acoustic transducers 920 (I) and acoustic transducers 920 (J), which may be positioned on respective neck straps 905.

In some embodiments, one or more of the acoustic transducers 920 (a) to 920 (J) may be used as output transducers (e.g., speakers). For example, acoustic transducer 920 (a) and/or acoustic transducer 920 (B) may be an in-ear earphone (earboud) or any other suitable type of headphone or speaker.

The configuration of the acoustic transducer 920 of the microphone array may vary. Although the augmented reality system 900 is shown in fig. 9 as having ten acoustic transducers 920, the number of acoustic transducers 920 may be greater or less than ten. In some embodiments, using a greater number of acoustic transducers 920 may increase the amount of audio information collected and/or the sensitivity and accuracy of the audio information. In contrast, using a smaller number of acoustic transducers 920 may reduce the computational power required by the associated controller 950 to process the collected audio information. Furthermore, the location of each acoustic transducer 920 of the microphone array may vary. For example, the locations of the acoustic transducers 920 may include defined locations on the user, defined coordinates on the frame 910, an orientation associated with each acoustic transducer 920, or some combination thereof.

The acoustic transducer 920 (a) and the acoustic transducer 920 (B) may be positioned on different portions of the user's ear, such as behind the pinna, behind the tragus, and/or within the auricle (auricle) or fossa. Alternatively, there may be additional acoustic transducers 920 on or around the ear in addition to the acoustic transducers 920 inside the ear canal. Positioning the acoustic transducer 920 near the ear canal of the user may enable the microphone array to collect information about how sound reaches the ear canal. By having at least two acoustic transducers of the plurality of acoustic transducers 920 located on both sides of the user's head (e.g., as binaural microphones), the augmented reality device 900 may simulate binaural hearing and capture a 3D stereo field around the user's head. In some embodiments, acoustic transducer 920 (a) and acoustic transducer 920 (B) may be connected to augmented reality system 900 via wired connection 930, while in other embodiments acoustic transducer 920 (a) and acoustic transducer 920 (B) may be connected to augmented reality system 900 via a wireless connection (e.g., a bluetooth connection). In still other embodiments, the acoustic transducer 920 (a) and the acoustic transducer 920 (B) may not be used in conjunction with the augmented reality system 900 at all.

The acoustic transducers 920 on the frame 910 may be positioned in a variety of different ways, including along the length of the temple (temp), across the bridge, above or below the display devices 915 (a) and 915 (B), or some combination thereof. The acoustic transducer 920 may also be oriented such that the microphone array is capable of detecting sound in a wide range of directions around a user wearing the augmented reality system 900. In some embodiments, an optimization process may be performed during the manufacture of the augmented reality system 900 to determine the relative positioning of each acoustic transducer 920 in the microphone array.

In some examples, the augmented reality system 900 may include or be connected to an external device (e.g., a paired device), such as a neck strap 905. The neck strap 905 generally represents any type or form of mating device. Accordingly, the following discussion of neck strap 905 may also apply to various other paired devices, such as charging boxes, smartwatches, smartphones, wrist straps, other wearable devices, hand-held controllers, tablet computers, laptop computers, other external computing devices, and the like.

As shown, the neck strap 905 may be coupled to the eyeglass apparatus 902 via one or more connectors. The connector may be wired or wireless and may include electronic components and/or non-electronic components (e.g., structural components). In some cases, the eyeglass apparatus 902 and the neck strap 905 can operate independently without any wired or wireless connection therebetween. Although fig. 9 shows the components of the eyeglass apparatus 902 and the components of the neck strap 905 being located at example locations on the eyeglass apparatus 902 and the neck strap 905, the components may be located elsewhere on the eyeglass apparatus 902 and/or the neck strap 905 and/or distributed differently on the eyeglass apparatus and/or the neck strap. In some embodiments, the components of the eyeglass apparatus 902 and the components of the neck strap 905 can be located on one or more additional peripheral devices paired with the eyeglass apparatus 902, the neck strap 905, or some combination thereof.

Pairing an external device (e.g., neck strap 905) with an augmented reality eyewear device may enable the eyewear device to implement the form factor of a pair of eyewear while still providing sufficient battery power and computing power for the extended capabilities. Some or all of the battery power, computing resources, and/or additional features of the augmented reality system 900 may be provided by, or shared between, the paired device and the eyeglass device, thus generally reducing the weight, thermal profile, and form factor of the eyeglass device while still retaining the desired functionality. For example, the neck strap 905 may allow components that would otherwise be included on the eyeglass apparatus to be included in the neck strap 905 because the user may bear a heavier weight load on their shoulders than the user bears on their heads. The neck strap 905 may also have a larger surface area with which to spread and disperse heat to the surrounding environment. Thus, the neck strap 905 may allow for greater battery capacity and computing power than would otherwise be possible on a standalone eyeglass device. Because the weight carried in the neck strap 905 is less invasive to the user than the weight carried in the eyeglass device 902, the user can afford to wear a lighter eyeglass device and carry or wear a paired device for a longer length of time than if the user were to wear a heavy, freestanding eyeglass device, thereby enabling the user to more fully integrate the artificial reality environment into his daily activities.

The neck strap 905 can be communicatively coupled with the eyeglass device 902, and/or communicatively coupled to other devices. These other devices may provide certain functions (e.g., tracking, positioning, depth map construction (depth mapping), processing, storage, etc.) for the augmented reality system 900. In the embodiment of fig. 9, the neck strap 905 may include two acoustic transducers (e.g., acoustic transducer 920 (I) and acoustic transducer 920 (J)) as part of the microphone array (or potentially forming its own microphone sub-array). The neck strap 905 may also include a controller 925 and a power supply 935.

The acoustic transducer 920 (I) and the acoustic transducer 920 (J) of the neck strap 905 may be configured to detect sound and convert the detected sound into an electronic format (analog or digital). In the embodiment of fig. 9, acoustic transducers 920 (I) and 920 (J) may be positioned on the neck strap 905, thereby increasing the distance between the neck strap's acoustic transducers 920 (I) and 920 (J) and other acoustic transducers 920 positioned on the eyewear device 902. In some cases, increasing the distance between the acoustic transducers 920 of the microphone array may improve the accuracy of the beamforming performed via the microphone array. For example, if sound is detected by the acoustic transducer 920 (C) and the acoustic transducer 920 (D), and the distance between the acoustic transducer 920 (C) and the acoustic transducer 920 (D) is greater than, for example, the distance between the acoustic transducer 920 (D) and the acoustic transducer 920 (E), the determined source location of the detected sound may be more accurate than if sound is detected by the acoustic transducer 920 (D) and the acoustic transducer 920 (E).

The controller 925 of the neck strap 905 may process information generated by sensors on the neck strap 905 and/or the augmented reality system 900. For example, the controller 925 may process information from the microphone array describing sounds detected by the microphone array. For each detected sound, the controller 925 may perform a direction-of-arrival (DOA) estimation to estimate the direction in which the detected sound arrives at the microphone array. When sound is detected by the microphone array, the controller 925 may populate the audio dataset with information. In embodiments where the augmented reality system 900 includes an inertial measurement unit, the controller 925 may calculate all inertial and spatial calculations from the IMU located on the eyeglass device 902. The connector may transfer information between the augmented reality system 900 and the neck strap 905, and between the augmented reality system 900 and the controller 925. Such information may be in the form of optical data, electrical data, wireless data, or any other form of data that may be transmitted. Moving the processing of information generated by the augmented reality system 900 to the neck strap 905 may reduce the weight of the eyeglass apparatus 902 and reduce heat, making the user more comfortable.

The power source 935 in the neck strap 905 can provide power to the eyeglass apparatus 902 and/or to the neck strap 905. The power source 935 may include, but is not limited to, a lithium ion battery, a lithium polymer battery, a disposable lithium battery, an alkaline battery, or any other form of power storage device. In some cases, power supply 935 may be a wired power supply. Including the power source 935 on the neck strap 905 instead of on the eyeglass device 902 may help better distribute weight and heat generated by the power source 935.

As noted, some artificial reality systems may substantially replace one or more of the user's multiple sensory perceptions of the real world with a virtual experience, rather than mixing artificial reality with real reality. One example of this type of system is a head mounted display system that covers a majority or all of the user's field of view, such as virtual reality system 1000 in fig. 10. The virtual reality system 1000 may include a front rigid body 1002 and a strap 1004 shaped to fit around the head of a user. The virtual reality system 1000 may also include an output audio transducer 1006 (a) and an output audio transducer 1006 (B). Further, although not shown in fig. 10, front rigid body 1002 may include one or more electronic components 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.

The artificial reality system may include various types of visual feedback mechanisms. For example, the display devices in the augmented reality system 900 and/or the virtual reality system 1000 may include one or more liquid crystal displays (Liquid Crystal Display, LCD), one or more light emitting diode (Light Emitting Diode, LED) displays, one or more micro LED displays, one or more organic LED (Organic Light Emitting Diode, OLED) displays, one or more digital light projection (Digital Light Project, DLP) micro displays, one or more liquid crystal on silicon (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 one display screen may be provided for each eye, which may allow additional flexibility for zoom adjustment or for correcting refractive errors of the user. Some of these artificial reality systems may also include an optical subsystem having one or more lenses (e.g., concave or convex, fresnel, tunable liquid, etc.) through which a user may view the display screen. These optical subsystems may be used for a variety of purposes, including collimating light (e.g., making an object appear at a greater distance than its physical distance), amplifying light (e.g., making an object appear larger than its physical size), and/or relaying light (e.g., to an eye of a viewer). These optical subsystems may be used in direct-view architectures (e.g., single lens configurations that collimate light directly but cause so-called pincushion) and/or in non-direct-view architectures (such as multi-lens configurations that produce so-called barrel-shaped distortion to eliminate pincushion).

Some of the plurality of artificial reality systems described herein may include one or more projection systems in addition to or in lieu of using a display screen. For example, the display device in the augmented reality system 900 and/or the display device in the virtual reality system 1000 may include a micro LED projector that projects light (e.g., using a waveguide) into the display device, such as a transparent combination lens that allows ambient light to pass through. The display device may refract the projected light toward the pupil of the user, and may enable the user to view both the artificial reality content and the real world at the same time. The display device may achieve this using any of a variety of different optical components including waveguide components (e.g., holographic waveguide elements, planar waveguide elements, diffractive waveguide elements, polarizing waveguide elements, and/or reflective waveguide elements), light manipulating surfaces and elements (e.g., diffractive elements and gratings, reflective elements and gratings, and refractive elements and gratings), coupling elements, and the like. The artificial reality system may also be configured with any other suitable type or form of image projection system, such as a retinal projector used in a virtual retinal display.

The artificial reality systems described herein may also include various types of computer vision components and subsystems. For example, the augmented reality system 900 and/or the virtual reality system 1000 may include one or more optical sensors, such as a two-dimensional (2D) camera or 3D camera, a structured light emitter and detector, a time-of-flight depth sensor, a single beam or scanning laser rangefinder, a 3D LiDAR sensor, and/or any other suitable type or form of optical sensor. The artificial reality system may process data from one or more of these sensors to identify the user's location, map the real world, provide the user with a background regarding the real world environment, and/or perform various other functions.

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

In some examples, the artificial reality systems described herein may also include tactile (i.e., haptic) feedback systems that may be incorporated into headwear, gloves, clothing, hand-held controllers, environmental devices (e.g., chairs, floor mats, etc.), and/or any other type of device or system. The haptic feedback system may provide various types of skin 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, fluid systems, and/or various other types of feedback mechanisms. The haptic feedback system may be implemented independently of, within, and/or in combination with other artificial reality devices.

By providing haptic sensations, auditory content, and/or visual content, an artificial reality system can create a complete virtual experience or enhance a user's real-world experience in a variety of contexts and environments. For example, an artificial reality system may assist or augment a user's perception, memory, or cognition within a particular environment. Some systems may enhance user interaction with others in the real world or may enable more immersive interactions with others in the virtual world. The artificial reality system may also be used for educational purposes (e.g., for teaching or training in schools, hospitals, government organizations, military organizations, commercial 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 a hearing aid, visual aid, etc.). Embodiments disclosed herein may implement or enhance the user's artificial reality experience in one or more of these contexts and environments, and/or in other contexts and environments.

The process parameters and sequence of steps described and/or illustrated herein are given by way of example only and may be varied as desired. For example, although the steps illustrated and/or described herein may be illustrated or discussed in a particular order, the steps need not be performed in the order illustrated or discussed. 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.

The previous description has been provided to enable others skilled in the art to best utilize various aspects of the exemplary embodiments disclosed herein. The 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 spirit and scope of the disclosure. The embodiments disclosed herein are to be considered in all respects as illustrative and not restrictive. In determining the scope of the present disclosure, reference should be made to the appended claims and their equivalents.

The terms "connected" and "coupled" as used in the specification and claims (and derivatives thereof) should be interpreted as allowing for direct connection and indirect (i.e., via other elements or components) unless otherwise indicated. Furthermore, the terms "a" or "an", as used in the description and claims, should be interpreted to mean at least one of "… …". Finally, for convenience in use, the terms "comprising" and "having" (and their derivatives) as used in the specification and claims, are interchangeable with the term "comprising" and have the same meaning.

Claims (20)

1. An apparatus, the apparatus comprising:

a lens stack, the lens stack comprising:

a first graded index liquid crystal lens; and

a second graded index liquid crystal lens, the second graded index liquid crystal lens being mated with the first graded index liquid crystal lens,

wherein the lens stack is configured to reach a target optical power based on the first optical power of the first graded index liquid crystal lens and the second optical power of the second graded index liquid crystal lens.

2. The apparatus of claim 1, wherein the first graded index liquid crystal lens and the second graded index liquid crystal lens are zoom lenses.

3. The apparatus of claim 1, wherein:

the first graded index liquid crystal lens comprises a first layer of mask, and the first layer of mask is positioned at one or more Fresnel resets of the first graded index liquid crystal lens; and is also provided with

The second graded index liquid crystal lens includes a second layer mask located at one or more fresnel resets of the second graded index liquid crystal lens.

4. The apparatus of claim 1, wherein the first optical power is different from the second optical power.

5. The apparatus of claim 4, wherein when the first power of the first graded index liquid crystal lens is changed, the second power of the second graded index liquid crystal lens is changed such that the first graded index liquid crystal lens and the second graded index liquid crystal lens maintain different powers.

6. The apparatus of claim 1, wherein:

the first graded index liquid crystal lens comprises a first layer mask; and is also provided with

The second graded index liquid crystal lens includes a second layer mask.

7. The apparatus of claim 6, wherein:

the first layer mask shields light scattered by the first graded index liquid crystal lens; and is also provided with

The second layer mask blocks light scattered by the second graded index liquid crystal lens.

8. The apparatus of claim 6, wherein:

the first layer mask is aligned with one or more fresnel resets of the first graded index liquid crystal lens; and is also provided with

The second layer mask is aligned with one or more fresnel resets of the second graded index liquid crystal lens.

9. The apparatus of claim 6, wherein the first graded index liquid crystal lens and the second graded index liquid crystal lens are disposed such that the first layer mask and the second layer mask are positioned between a first liquid crystal layer of the first graded index liquid crystal lens and a second liquid crystal layer of the second graded index liquid crystal lens.

10. The apparatus of claim 1, wherein the first graded index liquid crystal lens and the second graded index liquid crystal lens share a substrate.

11. A system, the system comprising:

a head mounted display, the head mounted display comprising:

a lens stack, the lens stack comprising:

a first graded index liquid crystal lens; and

a second graded index liquid crystal lens, the second graded index liquid crystal lens being mated with the first graded index liquid crystal lens,

wherein the lens stack is configured to reach a target optical power based on the first optical power of the first graded index liquid crystal lens and the second optical power of the second graded index liquid crystal lens.

12. The system of claim 11, wherein the first and second graded index liquid crystal lenses are zoom lenses.

13. The system of claim 11, wherein,

the first graded index liquid crystal lens comprises a first layer of mask, and the first layer of mask is positioned at one or more Fresnel resets of the first graded index liquid crystal lens; and is also provided with

The second graded index liquid crystal lens includes a second layer mask located at one or more fresnel resets of the second graded index liquid crystal lens.

14. The system of claim 11, wherein the first optical power is different from the second optical power.

15. The system of claim 14, wherein when the first power of the first graded index liquid crystal lens changes, the second power of the second graded index liquid crystal lens changes such that the first graded index liquid crystal lens and the second graded index liquid crystal lens maintain different powers.

16. The system of claim 11, wherein,

the first graded index liquid crystal lens comprises a first layer mask; and is also provided with

The second graded index liquid crystal lens includes a second layer mask.

17. The system of claim 16, wherein,

the first layer mask shields light scattered by the first graded index liquid crystal lens; and

the second layer mask blocks light scattered by the second graded index liquid crystal lens.

18. The system of claim 16, wherein,

the first layer mask is aligned with one or more fresnel resets of the first graded index liquid crystal lens; and

the second layer mask is aligned with one or more fresnel resets of the second graded index liquid crystal lens.

19. The system of claim 16, wherein the first graded index liquid crystal lens and the second graded index liquid crystal lens are disposed such that the first layer mask and the second layer mask are positioned between a first liquid crystal layer of the first graded index liquid crystal lens and a second liquid crystal layer of the second graded index liquid crystal lens.

20. A method of manufacturing, the method comprising:

the lens stack is assembled by:

setting a first graded index liquid crystal lens; and

a second graded index liquid crystal lens is arranged, the second graded index liquid crystal lens is matched with the first graded index liquid crystal lens,

wherein the lens stack is configured to reach a target optical power based on the first optical power of the first graded index liquid crystal lens and the second optical power of the second graded index liquid crystal lens.