CN117665987A - Graded index liquid crystal lens with carbon nanotube spacers - Google Patents

Abstract

The present invention relates to graded index liquid crystal lenses having carbon nanotube spacers. There is provided an optical element comprising: a first optical substrate; a second optical substrate covering at least a portion of the first optical substrate; a liquid crystal layer disposed in a cell gap between the first optical substrate and the second optical substrate; and a plurality of carbon nanotube columns extending across the cell gap between the first optical substrate and the second optical substrate. The aspect ratio of the carbon nanotube string may be at least about 2:1, and the carbon nanotube string may be configured to maintain a uniform cell gap thickness.

Description

Graded index liquid crystal lens with carbon nanotube spacers

Cross Reference to Related Applications

The present application claims priority from U.S. provisional patent application Ser. No. 63/404,260, filed on 7 at 9 at 2022, and U.S. non-provisional patent application Ser. No. 18/295,099, filed on 3 at 4 at 2023, the disclosures of which are incorporated herein by reference in their entireties.

Technical Field

The present invention relates to a graded-index (GRIN) Liquid Crystal (LC) lens having carbon nanotube spacers.

Background

Various optical engineering applications include ophthalmic lenses, contact lenses, and vision correction elements in augmented reality (augmented reality, AR) systems and Virtual Reality (VR) systems, among others.

Disclosure of Invention

In one embodiment of the present invention, there is provided an optical element including: a first optical substrate; a second optical substrate covering at least a portion of the first optical substrate; a liquid crystal layer disposed in a cell gap between the first optical substrate and the second optical substrate; and a plurality of carbon nanotube columns extending across the cell gap between the first optical substrate and the second optical substrate.

In another embodiment of the present invention, there is provided an augmented reality (augmented reality, AR) system or Virtual Reality (VR) system, the AR system or VR system comprising: AR headset or VR headset; and a variable power lens including the optical element according to the above embodiment.

In still another embodiment of the present invention, there is provided a liquid crystal lens including: a liquid crystal layer disposed in a cell gap between the first optical substrate and the second optical substrate; and a plurality of carbon nanotube columns extending across the cell gap and configured to maintain a uniform spacing between the first optical substrate and the second optical substrate.

In yet another embodiment of the present invention, a method is provided, the method comprising: forming a plurality of carbon nanotube columns over a first optical substrate, the plurality of carbon nanotube columns extending away from the first optical substrate; forming a second optical substrate over the first optical substrate, wherein the plurality of carbon nanotube pillars define a cell gap between the first optical substrate and the second optical substrate; and forming a liquid crystal layer in the cell gap.

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 is a cross-sectional view of a GRIN LC lens including carbon nanotube spacers (carbon nanotube spacer) according to some embodiments.

Fig. 2 illustrates an exemplary method of forming an array of carbon nanotube spacers, according to some embodiments.

Fig. 3 is a schematic representation of single-walled carbon nanotubes (single wall carbon nanotube, SWCNT) and multi-walled carbon nanotubes (multi-walled carbon nanotube, MWCNT) according to certain embodiments.

Fig. 4 summarizes the characteristics of exemplary single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) according to various embodiments.

Fig. 5 is an illustration of exemplary augmented reality glasses that may be used in connection with embodiments of the present disclosure.

Fig. 6 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. Rather, the present disclosure covers all modifications, equivalents, and alternatives falling within the scope of the appended claims.

Detailed Description

In a variety of optical engineering applications, including ophthalmic lenses, contact lenses, and vision correction 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, as will be appreciated, achieving a continuous phase retardation distribution over a large aperture (> 10 mm) LC lens may be challenged by the finite birefringence (< 0.4) of the LC materials and the mechanical compliance 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 one branch of optics in which the optical effect is produced by a spatial grading of the refractive index of the material. For example, progressive refractive 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 a radial/cylindrical index graded configuration, the refractive index profile may continuously vary from the center line of the optical axis to the periphery in the lateral direction, such that the surface of 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.

Graded index lenses utilize spatially defined refractive index grading over the viewing aperture of the lens to impart an optical phase profile at a selected design wavelength. In certain examples, GRIN lenses may have a planar form factor (e.g., a disk shape), and may improve lens performance relative to lenses formed from materials having a single spatially invariant refractive index (e.g., contrast lenses made of glass or quartz).

The GRIN-type zoom 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. Therefore, 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 systems, the tunable architecture may include a plurality of discrete ring electrodes formed on one or more LC layers within the optical aperture of the lens. During operation, a different voltage may be applied to each electrode, which may be used to locally adjust the refractive index of the LC material. As will be appreciated, patterning of multiple electrodes can create manufacturing challenges and also result in performance defects including transmission loss, reduced focusing power, and/or optical artifacts (e.g., haze) and/or ghosting) due to angle diffraction caused by subcritical electrode dimensions or gaps between adjacent electrodes. In some embodiments, the inter-electrode gap (inter-electrode gap) across the viewing aperture of the zoom GRIN LC lens may be greater than about 1 micron.

As used herein, the terms "haze" and "clarity" may refer to optical phenomena related to the transmission of light through a material, and may be due to, for example, refraction of light within the material due to reflection of light from one or more surfaces of the material and/or a second phase or porosity. Haze may be related to the amount of light that experiences wide angle scattering (i.e., an angle greater than 2.5 ° from normal) and a corresponding loss of transmission contrast, while sharpness may be related to the amount of light that experiences narrow angle scattering (i.e., an angle less than 2.5 ° from normal) and the concomitant loss of optical sharpness or "see-through quality".

Despite recent advances, it would be advantageous to provide a GRIN LC lens design that is manufacturable and economical and that is configured to operate without significant haze or ghosting, or loss of transmissivity. Such GRIN LC lens designs may be configured to provide a high zoom range with high optical power and commercially relevant response time over a large aperture. Accordingly, the present disclosure relates to GRIN LC lenses of large aperture (about 50mm in diameter) that can operate at fast switching times (< 1 second) over a large optical power range (e.g., 0 to 3 diopters). For example, an exemplary GRIN LC lens includes a relatively large cell gap with good cell gap uniformity. As disclosed herein, carbon nanotubes may be implemented as offset elements (i.e., spacers) to create and maintain a large and uniform cell gap between opposing substrates. The carbon nanotubes may be configured as columnar spacers that provide a constant and uniform cell gap.

According to an example embodiment, an optical element, such as a GRIN LC lens, may include a first optical substrate, a second optical substrate covering at least a portion of the first optical substrate, a liquid crystal layer disposed within a cell gap between the first optical substrate and the second optical substrate, and a plurality of carbon nanotube columns extending across the cell gap between the first optical substrate and the second optical substrate. The first electrode layer may be disposed between the liquid crystal layer and the first optical substrate, and the second electrode layer may be disposed between the liquid crystal layer and the second optical substrate.

The first substrate and the second substrate may be transparent and may define an optical aperture of the GRIN LC lens. As used herein, an "optical" substrate may be characterized by: transmittance in the visible spectrum of at least about 80%, such as 80%, 90%, 95%, 97% or 99%, including ranges between any of the foregoing values; and a bulk haze (bulk haze) of less than about 10%, such as 0%, 1%, 2%, 4%, 6% or 8%, including ranges between any of the foregoing values.

The electrodes may comprise one or more conductive materials, such as metals, conductive polymers, or conductive oxides. The electrode may comprise a blanket or patterned structure, and may comprise a conductive material (i.e., particles) dispersed throughout a matrix. For example, the conductive particles may include nanoparticles, nanowires (e.g., silver nanowires), nanotubes (e.g., carbon nanotubes), transparent conductive oxides, graphene (e.g., graphene platelet structures), graphene oxide, fluorinated graphene, hydrogenated graphene, other graphene derivatives, and carbon black. Exemplary transparent conductive oxides (transparent conductive oxide, TCO) include Indium Tin Oxide (ITO) and indium gallium zinc oxide (indium gallium zinc oxide, IGZO), although other TCOs are also contemplated. In some embodiments, the electrode may comprise a low melting point composition (e.g., an alloy), such as indium, tin, gallium, and the like. In some embodiments, the electrode may have a conductivity of at least about 1S/cm.

The width (diameter) of the exemplary carbon nanotubes may range from about 0.5nm to about 100nm, such as 0.5nm, 1nm, 2nm, 3nm, 4nm, 5nm, 10nm, 20nm, 50nm, or 100nm, including ranges between any of the foregoing values, and the length of the exemplary carbon nanotubes may range from about 10 microns to about 50 microns, such as 10 microns, 20 microns, 30 microns, 40 microns, or 50 microns, including ranges between any of the foregoing values. The carbon nanotubes are characterized in that: aspect ratio (aspect ratio) of at least 1:1, e.g., 1:1, 2:1;5:1, 10:1, 20:1, 50:1, 100:1, 200:1, 500:1, 1000:1, 2000:1, 5000:1, 10000:1, or more, including ranges between any of the foregoing values. According to various embodiments, the carbon nanotubes may have a single-wall structure or a multi-wall structure.

In some embodiments, the carbon nanotubes may have planar sidewalls or substantially planar sidewalls, and the sidewalls may be inclined at any suitable angle relative to the major surface of the substrate. For example, the carbon nanotubes may have a cylindrical shape and may be orthogonally positioned relative to the major surface of the substrate. Alternatively, the carbon nanotubes may have a conical shape, wherein the sidewalls may be oriented at any suitable angle (45+.ltoreq.θ <90 °).

The plurality of carbon nanotubes may be arranged between the substrates in any suitable arrangement (e.g., an irregular array or a regular array). The spacing and/or configuration of the carbon nanotubes may be selected to maintain a uniform and constant cell gap between the substrates. In some embodiments, the plurality of carbon nanotubes may be self-similar. Alternatively, the cross-sectional shape and size of the plurality of carbon nanotubes may be independently controlled. Methods of fabricating carbon nanotube spacers include laser ablation, chemical vapor deposition, arc discharge, and the like.

According to various embodiments, incorporating high aspect ratio carbon nanotube spacers into GRIN LC lenses may reduce light scattering and light leakage relative to a comparative spacer architecture, which may reduce haze during lens operation, and improve both contrast and modulation transfer functions. That is, the carbon nanotubes may absorb light, thereby weakening the amount of scattered light. Furthermore, carbon nanotubes may have a greater tensile strength relative to the comparative spacer material, which may allow for the use of a smaller number of spacers. In certain embodiments, the conductive carbon nanotube spacers may be incorporated into electrodes and/or bus architecture of the optical element.

Features from any of the various embodiments described herein may be used in combination with one another in accordance with the general principles described herein. These and other embodiments, features and advantages will be more fully understood after reading the following detailed description in conjunction with the accompanying drawings and claims.

A detailed description of a graded index (GRIN) liquid crystal lens having carbon nanotube spacers will be provided below with reference to fig. 1 to 6. The discussion related to fig. 1 relates to an exemplary GRIN LC lens architecture having an array of high aspect ratio carbon nanotube spacers located in and maintaining a gap between opposing optically quality substrates. The discussion related to fig. 2 relates to an exemplary method of fabricating an array of carbon nanotube spacers. The discussion associated with fig. 3 and 4 relates to illustrative carbon nanotube structures and characteristics. The discussion related to fig. 5 and 6 relates to an exemplary virtual reality device and augmented reality device that may include one or more GRIN LC lenses as disclosed herein.

Referring to fig. 1, fig. 1 shows a cross-sectional view of a portion of an exemplary GRIN LC lens 100 having an optical aperture 102. The GRIN LC lens includes a pair of optical substrates 112, 114 defining a liquid crystal filled cell gap 120 between the pair of substrates. The substrates 112, 114 may be formed of glass or another optically transparent and insulating material, and the thickness of each substrate may range from about 100 microns to 300 microns, such as 100 microns, 150 microns, 200 microns, 250 microns, or 300 microns, including ranges between any of the above.

In the illustrated embodiment, the liquid crystal layer 124 is disposed within the cell gap 120 and an array of carbon nanotube spacers 130 extends across the cell gap 120 and the array of carbon nanotube spacers 130 is configured to maintain a uniform spacing between the substrates 112, 114. In addition, the electrode architecture may be configured to apply an electrical bias across the cell gap 120 to tune the orientation of the liquid crystal molecules 126 within the liquid crystal layer 124.

Each substrate 112, 114 may be metallized with a respective electrode (also referred to as an electrode layer) 142, 144, and another electrode layer 143 may be disposed adjacent to the liquid crystal layer 124. The electrode layers 142, 143 may be patterned, for example, to cover discrete portions of the liquid crystal layer 124 between the carbon nanotube spacers 130. Exemplary electrode materials include transparent conductive oxides such as Indium Tin Oxide (ITO).

The electrode layers 143, 144 are each insulated from the liquid crystal layer 124 by a respective dielectric layer 153, 154 (e.g., polyimide layer) facing the cell gap. The two opposite ends of the carbon nanotube spacer 130 may directly contact the respective dielectric layers. GRIN LC lens 100 may also include a metallization architecture 160 including a bus 162 disposed between insulating layers 164, 166, electrically connected to selected regions of electrodes 142, 143, for example, by conductive vias 168 for providing voltages to selected regions of liquid crystal layer 124. The presently disclosed lens architecture may exhibit improved optical performance (including reduced bulk haze and parallax) and improved manufacturability and cost relative to comparative GRIN LC lenses.

Referring to fig. 2, fig. 2 depicts an exemplary method of fabricating an array of carbon nanotube spacers. As shown in a of fig. 2, a portion of the GRIN LC lens architecture may include, from bottom to top, a glass substrate 202, an electrode layer 204, and a dielectric layer 206. Referring to B of fig. 2, a photoresist layer 210 (e.g., a positive photoresist layer) may be formed over the dielectric layer 206. The photoresist layer 210 may be formed, for example, by spin coating, followed by curing by one or both of heating and exposure to radiation (e.g., UV radiation).

Referring to fig. 2C, a masking layer (not shown) may be formed over the photoresist layer 210 and patterned, and unmasked portions (i.e., exposed portions) 212 of the photoresist layer 210 may be exposed to light. Referring to D of fig. 2, the exposed portion 212 of the photoresist layer may be removed by exposing the photoresist layer 210 to a photoresist developer to form a pattern of vias 214 that extend through the photoresist layer and expose portions of the dielectric layer 206. Then, referring to E of fig. 2, a seed layer 220 may be deposited over the patterned structure of D of fig. 2, including directly over dielectric layer 206 within via 214. The seed layer 220 may include, for example, iron nanoparticles. As shown in F of fig. 2, a lift-off process may be used to remove undeveloped portions of photoresist layer 210 and overlying portions of seed layer 220, thereby leaving patterned seed layer 220 defining regions for Carbon Nanotube (CNT) growth. Vertically aligned single-wall or multi-wall CNT pillars 230 may be formed by anisotropically growing from patterned seed layer 220.

A schematic drawing depicting the architecture of multi-walled carbon nanotubes and single-walled carbon nanotubes is shown in fig. 3. Selected characteristics of multi-walled carbon nanotubes (including length-modified multi-walled carbon nanotubes) and single-walled carbon nanotubes are listed in fig. 4.

According to some embodiments, an electrically tunable GRIN LC lens includes a Liquid Crystal (LC) layer disposed within a cell gap between a pair of opposing optically quality substrates, wherein the gap width, and thus the spacing between the substrates, is uniform at least within the viewing aperture of the lens. The optically quality substrate may comprise, for example, glass or a polymer composition. According to particular embodiments, high aspect ratio Carbon Nanotube (CNT) pillars are located within cell gaps between substrates. The CNT pillars are configured to maintain a large cell gap and uniform gap size while helping to minimize light scattering during lens operation. A large and uniform cell gap can advantageously affect performance attributes of an AR/VR headset including the disclosed lenses, such as low haze and good off-axis performance.

Exemplary embodiments of the invention

Example 1: an optical element comprising a first optical substrate; a second optical substrate covering at least a portion of the first optical substrate; a liquid crystal layer disposed in a cell gap between the first optical substrate and the second optical substrate; and a plurality of carbon nanotube columns extending across the cell gap between the first optical substrate and the second optical substrate.

Example 2: the optical element of embodiment 1 wherein the first optical substrate and the second optical substrate comprise glass.

Example 3: the optical element of any one of embodiments 1 and 2, wherein the thickness of the first optical substrate and the thickness of the second optical substrate each range from about 100 microns to about 300 microns.

Example 4: the optical element of any one of embodiments 1-3, wherein an inter-substrate dimension of the cell gap is spatially invariant over a viewing aperture of the optical element.

Example 5: the optical element of any one of embodiments 1-4, wherein the inter-substrate dimension of the cell gap ranges from about 5 microns to about 50 microns.

Example 6: the optical element of any one of embodiments 1-5, wherein the carbon nanotube string has a length of from about 5 microns to about 50 microns.

Example 7: the optical element of any one of embodiments 1-6, wherein the carbon nanotube string has a diameter of from about 2nm to about 50nm.

Example 8: the optical element of any one of embodiments 1-7, wherein the carbon nanotube string has an aspect ratio of at least about 2:1.

Example 9: the optical element of any one of embodiments 1-8, wherein the plurality of carbon nanotube columns are arranged in a regular array between the first optical substrate and the second optical substrate.

Example 10: the optical element of any one of embodiments 1-9, wherein the plurality of carbon nanotube columns are configured to maintain a uniform cell gap between the first optical substrate and the second optical substrate.

Example 11: the optical element of any one of embodiments 1-10, wherein the optical element comprises an observation aperture extending through the first optical substrate, the second optical substrate, and through the liquid crystal layer, and the observation aperture comprises at least one carbon nanotube column of the plurality of carbon nanotube columns; and the viewing aperture has a transmittance of at least about 80% and a bulk haze of less than about 10% over the visible spectrum.

Example 12: the optical element of any one of embodiments 1 to 11, further comprising a first electrode layer disposed between the liquid crystal layer and the first optical substrate; and a second electrode layer disposed between the liquid crystal layer and the second optical substrate.

Example 13: an augmented reality system (AR) or Virtual Reality (VR) system comprising an AR headset or VR headset; and a variable power lens comprising the optical element according to any one of embodiments 1 to 12.

Example 14: a liquid crystal lens comprising a liquid crystal layer disposed in a cell gap between the first optical substrate and the second optical substrate; and a plurality of carbon nanotube columns extending across the cell gap and configured to maintain a uniform spacing between the first optical substrate and the second optical substrate.

Example 15: the liquid crystal lens of embodiment 14, wherein the inter-substrate dimension of the cell gap ranges from about 5 microns to about 50 microns.

Example 16: the liquid crystal lens of any of embodiments 14 and 15, wherein the carbon nanotube string has an aspect ratio of at least about 2:1.

Example 17: the liquid crystal lens of any one of embodiments 14-16, wherein the liquid crystal lens comprises a viewing aperture extending through the first optical substrate, the second optical substrate, and through the liquid crystal layer, and the viewing aperture comprises at least one carbon nanotube column of the plurality of carbon nanotube columns; and the viewing aperture has a transmittance of at least about 80% and a bulk haze of less than about 10% in the visible spectrum.

Example 18: the liquid crystal lens according to any one of embodiments 14 to 17, further comprising: a first electrode layer disposed between the liquid crystal layer and the first optical substrate; and a second electrode layer disposed between the liquid crystal layer and the second optical substrate.

Example 19: a method comprising: forming a plurality of carbon nanotube columns over a first optical substrate, the plurality of carbon nanotube columns extending away from the first optical substrate; forming a second optical substrate over the first optical substrate, wherein the plurality of carbon nanotube pillars define a cell gap between the first optical substrate and the second optical substrate; and forming a liquid crystal layer in the cell gap.

Example 20: the method of embodiment 19, wherein forming the plurality of carbon nanotube columns comprises: (a) forming a dielectric layer over the first optical substrate, (b) forming a template layer over the dielectric layer, (c) etching the template layer to form a plurality of vias extending completely through the template layer, (d) depositing a seed layer over exposed portions of the dielectric layer within the plurality of vias, and (e) exposing the seed layer to a carbon nanotube precursor to form carbon nanotube pillars.

Example 21: the method of embodiment 20, wherein the seed layer comprises iron nanoparticles.

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 is somehow adjusted before being presented to a user, and may include, for example, virtual reality, augmented 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., augmented reality system 500 in FIG. 5) or NEDs that visually immerse the user in artificial reality (e.g., virtual reality system 600 in FIG. 6). 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. 5, the augmented reality system 500 may include an eyeglass device 502 having a frame 510 configured to hold a left display device 515 (a) and a right display device 515 (B) in front of both eyes of a user. The left display device 515 (a) and the right display device 515 (B) may act together or independently to present an image or series of images to the user. Although the augmented reality system 500 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 500 may include one or more sensors, such as sensor 540. The sensor 540 may generate measurement signals in response to movement of the augmented reality system 500 and may be located on substantially any portion of the frame 510. The sensor 540 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 500 may or may not include the sensor 540, or may include more than one sensor. In embodiments where the sensor 540 includes an IMU, the IMU may generate calibration data based on measurement signals from the sensor 540. Examples of the sensor 540 may include, but are not limited to, an accelerometer, a gyroscope, a magnetometer, other suitable types of sensors that detect motion, a sensor for IMU error correction, or some combination thereof.

In some examples, the augmented reality system 500 may also include a microphone array having a plurality of acoustic transducers 520 (a) through 520 (J), collectively referred to as acoustic transducers 520. The acoustic transducer 520 may represent a transducer that detects changes in air pressure caused by sound waves. Each acoustic converter 520 may be configured to detect sound and convert the detected sound to an electronic format (e.g., analog format or digital format). The microphone array in fig. 5 may for example comprise ten acoustic transducers: acoustic transducer 520 (a) and acoustic transducer 520 (B) that may be designed to be placed within respective ears of a user; acoustic transducer 520 (C), acoustic transducer 520 (D), acoustic transducer 520 (E), acoustic transducer 520 (F), acoustic transducer 520 (G), and acoustic transducer 520 (H), which may be located at different locations on frame 510; and/or an acoustic transducer 520 (I) and an acoustic transducer 520 (J) that may be located on respective neck straps 505.

In some embodiments, one or more of acoustic transducers 520 (a) to 520 (J) may be used as output transducers (e.g., speakers). For example, acoustic transducer 520 (a) and/or acoustic transducer 520 (B) may be an ear bud or any other suitable type of headphone or speaker.

The configuration of the acoustic transducer 520 of the microphone array may vary. Although the augmented reality system 500 is shown in fig. 5 as having ten acoustic transducers 520, the number of acoustic transducers 520 may be greater or less than ten. In some embodiments, using a greater number of acoustic transducers 520 may increase the amount of audio information collected and/or the sensitivity and accuracy of the audio information. Conversely, using a smaller number of acoustic transducers 520 may reduce the computational power required by the associated controller 550 to process the collected audio information. Furthermore, the position of each acoustic transducer 520 of the microphone array may vary. For example, the locations of the acoustic transducers 520 may include defined locations on the user, defined coordinates on the frame 510, an orientation associated with each acoustic transducer 520, or some combination thereof.

Acoustic transducer 520 (a) and acoustic transducer 520 (B) may be located on different portions of a 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 520 on or around the ear in addition to the acoustic transducers 520 in the ear canal. Positioning the acoustic transducer 520 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 of the plurality of acoustic transducers 520 located on both sides of the user's head (e.g., as binaural microphones), the augmented reality device 500 may simulate binaural hearing and capture a 3D stereo field around the user's head. In some embodiments, acoustic transducer 520 (a) and acoustic transducer 520 (B) may be connected to augmented reality system 500 via wired connection 530, while in other embodiments acoustic transducer 520 (a) and acoustic transducer 520 (B) may be connected to augmented reality system 500 via a wireless connection (e.g., a bluetooth connection). In still other embodiments, acoustic transducer 520 (a) and acoustic transducer 520 (B) may not be used in conjunction with augmented reality system 500 at all.

The acoustic transducer 520 on the frame 510 may be positioned in a variety of different ways, including along the length of the temple, across the bridge, above or below the left display device 515 (a) and the right display device 515 (B), or some combination thereof. The acoustic transducer 520 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 500. In some embodiments, an optimization process may be performed during the manufacture of the augmented reality system 500 to determine the relative positioning of each acoustic transducer 520 in the microphone array.

In some examples, the augmented reality system 500 may include or be connected to an external device (e.g., a pairing device), such as the neck strap 505. The neck strap 505 generally represents any type or form of mating device. Accordingly, the following discussion of neck strap 505 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 505 may be coupled to the eyeglass apparatus 502 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 502 and the neck strap 505 can operate independently without any wired or wireless connection therebetween. Although fig. 5 shows the components of the eyeglass apparatus 502 and the components of the neck strap 505 in example locations on the eyeglass apparatus 502 and the neck strap 505, the components may be located elsewhere on the eyeglass apparatus 502 and/or the neck strap 505 and/or distributed differently on the eyeglass apparatus 502 and/or the neck strap 505. In some embodiments, the components of the eyeglass apparatus 502 and the components of the neck strap 505 can be located on one or more additional peripheral devices paired with the eyeglass apparatus 502, on the neck strap 505, or some combination thereof.

Pairing an external device (e.g., neck strap 505) with an augmented reality eyewear device may enable the eyewear device to implement the form factor of a pair of eyewear, and still provide sufficient battery capacity 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 500 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 505 may allow components that would otherwise be included on the eyeglass apparatus to be included in the neck strap 505 because the user's shoulders may bear a heavier weight load than the user's head may bear. The neck strap 505 may also have a larger surface area over which heat is spread and dispersed to the surrounding environment. Thus, the neck strap 505 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 505 is less invasive to the user than the weight carried in the eyeglass device 502, 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 505 may be communicatively coupled with the eyeglass device 502, and/or communicatively coupled to other devices. These other devices may provide certain functionality (e.g., tracking, positioning, depth map construction, processing, storage, etc.) for the augmented reality system 500. In the embodiment of fig. 5, the neck strap 505 may include two acoustic transducers (e.g., acoustic transducer 520 (I) and acoustic transducer 520 (J)) as part of the microphone array (or potentially forming its own microphone sub-array). The neck strap 505 may also include a controller 525 and a power source 535.

The acoustic transducer 520 (I) and the acoustic transducer 520 (J) of the neck strap 505 may be configured to detect sound and convert the detected sound into an electronic format (analog or digital). In the embodiment of fig. 5, acoustic transducers 520 (I) and 520 (J) may be located on the neck strap 505, thereby increasing the distance between the acoustic transducers 520 (I) and 520 (J) of the neck strap and other acoustic transducers 520 located on the eyeglass apparatus 502. In some cases, increasing the distance between the acoustic transducers 520 of the microphone array can improve the accuracy of beamforming performed via the microphone array. For example, if sound is detected by acoustic transducer 520 (C) and acoustic transducer 520 (D), and the distance between acoustic transducer 520 (C) and acoustic transducer 520 (D) is greater than, for example, the distance between acoustic transducer 520 (D) and acoustic transducer 520 (E), the determined source location of the detected sound may be more accurate than if sound is detected by acoustic transducer 520 (D) and acoustic transducer 520 (E).

The controller 525 of the neck strap 505 may process information generated by sensors on the neck strap 505 and/or the augmented reality system 500. For example, the controller 525 may process information from the microphone array describing sounds detected by the microphone array. For each detected sound, the controller 525 may perform an estimation of the direction-of-arrival (DOA) to estimate the direction of arrival of the detected sound at the microphone array. When the microphone array detects sound, the controller 525 may populate the audio data set with information. In embodiments where the augmented reality system 500 includes an inertial measurement unit, the controller 525 may calculate all inertial and spatial operations from the IMU located on the eyeglass device 502. The connector may communicate information between the augmented reality system 500 and the neck strap 505, and between the augmented reality system 500 and the controller 525. Such information may be in the form of optical data, electrical data, wireless data, or any other form of data that may be transmitted. Transferring the processing of information generated by the augmented reality system 500 to the neck strap 505 may reduce the weight of the eyeglass apparatus 502 and reduce heat, making it more comfortable for the user.

The power source 535 in the neck strap 505 may provide power to the eyeglass apparatus 502 and/or the neck strap 505. Power source 535 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 source 535 may be a wired power source. The inclusion of the power source 535 on the neck strap 505 rather than on the eyeglass device 502 may help better distribute weight and heat generated by the power source 535.

As noted, some artificial reality systems may replace one or more of the multiple sensory sensations of the real world with a virtual experience in general, rather than mixing the artificial reality with the 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 600 in fig. 6. The virtual reality system 600 may include a front rigid body 602 and a strap 604 shaped to fit around the head of the user. The virtual reality system 600 may also include an output audio transducer 606 (a) and an output audio transducer 606 (B). Further, although not shown in fig. 6, front rigid body 602 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 device in the augmented reality system 500 and/or the display device in the virtual reality system 600 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 in adjusting or correcting the user's refractive error for zooming. Some of these artificial reality systems may also include an optical subsystem having one or more lenses (e.g., concave or convex lenses, fresnel lenses, tunable liquid lenses, 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), magnifying 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 directly collimate light but cause so-called pincushion distortion) and/or in non-direct-view architectures (such as multi-lens configurations that produce so-called barrel distortion to eliminate pincushion distortion).

Some of the 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 500 and/or the display device in the virtual reality system 600 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 500 and/or the virtual reality system 600 may include one or more optical sensors, such as a two-dimensional (2D) camera or 3D camera, structured light emitters and detectors, time-of-flight depth sensors, single beam or scanning laser rangefinder, 3D LiDAR sensors, 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 system 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 shown or discussed in a particular order, the steps need not be performed in the order shown 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, are to be interpreted as meaning 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.

It will be understood that when an element (e.g., a layer or region) is referred to as being formed on, deposited on, or disposed "on" or "over" another element, it can be directly on at least a portion of the other element or one or more intervening elements may also be present. In contrast, when an element is referred to as being "directly on" or "directly over" another element, it can be on at least a portion of the other element without intervening elements present.

As used herein, the term "substantially" with respect to a given parameter, characteristic or condition may refer to and include the extent to which a person skilled in the art will understand that the given parameter, characteristic or condition has a lesser degree of variation (e.g., within acceptable manufacturing tolerances). For example, depending on the particular parameter, characteristic, or condition that is substantially met, the parameter, characteristic, or condition may be at least about 90% met, at least about 95% met, or even at least about 99% met.

As used herein, in certain embodiments, the term "about" with respect to a particular value or range of values may refer to and include the value as well as all values within 10% of the value. Thus, by way of example, in certain embodiments, a value of "50" referred to as "about 50" may include a value equal to 50±5, i.e., a value in the range of 45 to 55.

While the transitional phrase "comprising" may be used to disclose various features, elements, or steps of a particular embodiment, it should be understood that it is implicit to include those alternative embodiments that may be described using the transitional phrase "consisting of … …" or "consisting essentially of … …. Thus, for example, implicit alternative embodiments of liquid crystal materials containing a cyanobiphenyl compound include embodiments in which the liquid crystal material consists essentially of a cyanobiphenyl compound and embodiments in which the liquid crystal material consists of a cyanobiphenyl compound.

Claims (20)

1. An optical element, the optical element comprising:

a first optical substrate;

a second optical substrate covering at least a portion of the first optical substrate;

a liquid crystal layer disposed in a cell gap between the first optical substrate and the second optical substrate; and

a plurality of carbon nanotube columns extending across the cell gap between the first optical substrate and the second optical substrate.

2. The optical element of claim 1, wherein the first and second optical substrates comprise glass.

3. The optical element of claim 1, wherein the thickness of the first optical substrate and the thickness of the second optical substrate each range from about 100 microns to about 300 microns.

4. The optical element of claim 1, wherein an inter-substrate dimension of the cell gap is spatially invariant over a viewing aperture of the optical element.

5. The optical element of claim 1, wherein the inter-substrate dimensions of the cell gap range from about 5 microns to about 50 microns.

6. The optical element of claim 1, wherein the carbon nanotube string has a length of from about 5 microns to about 50 microns.

7. The optical element of claim 1, wherein the carbon nanotube string has a diameter of from about 2nm to about 50nm.

8. The optical element of claim 1, wherein the carbon nanotube string has an aspect ratio of at least about 2:1.

9. The optical element of claim 1, wherein the plurality of carbon nanotube columns are arranged in a regular array between the first optical substrate and the second optical substrate.

10. The optical element of claim 1, wherein the plurality of carbon nanotube columns are configured to maintain a uniform cell gap between the first optical substrate and the second optical substrate.

11. The optical element of claim 1, wherein,

the optical element includes a viewing aperture extending through the first optical substrate, the second optical substrate, and the liquid crystal layer, and the viewing aperture includes at least one carbon nanotube column of the plurality of carbon nanotube columns; and is also provided with

The viewing aperture comprises a transmittance of at least about 80% and a bulk haze of less than about 10% over the visible spectrum.

12. The optical element of claim 1, further comprising:

a first electrode layer disposed between the liquid crystal layer and the first optical substrate; and

and a second electrode layer disposed between the liquid crystal layer and the second optical substrate.

13. An augmented reality AR system or virtual reality VR system, the AR system or VR system comprising:

AR headset or VR headset; and

a variable power lens comprising the optical element of claim 1.

14. A liquid crystal lens, the liquid crystal lens comprising:

a liquid crystal layer disposed in a cell gap between the first optical substrate and the second optical substrate; and

A plurality of carbon nanotube columns extending across the cell gap and configured to maintain a uniform spacing between the first optical substrate and the second optical substrate.

15. The liquid crystal lens of claim 14, wherein the inter-substrate dimension of the cell gap ranges from about 5 microns to about 50 microns.

16. The liquid crystal lens of claim 14, wherein the carbon nanotube string has an aspect ratio of at least about 2:1.

17. The liquid crystal lens according to claim 14, wherein,

the liquid crystal lens includes a viewing aperture extending through the first optical substrate, the second optical substrate, and the liquid crystal layer, and the viewing aperture includes at least one carbon nanotube column of the plurality of carbon nanotube columns; and is also provided with

The viewing aperture includes a transmittance of at least about 80% and a bulk haze of less than about 10% in the visible spectrum.

18. The liquid crystal lens of claim 14, further comprising:

a first electrode layer disposed between the liquid crystal layer and the first optical substrate; and

and a second electrode layer disposed between the liquid crystal layer and the second optical substrate.

19. A method, the method comprising:

forming a plurality of carbon nanotube columns over a first optical substrate, the plurality of carbon nanotube columns extending away from the first optical substrate;

forming a second optical substrate over the first optical substrate, wherein the plurality of carbon nanotube pillars define a cell gap between the first optical substrate and the second optical substrate; and

a liquid crystal layer is formed in the cell gap.

20. The method of claim 19, wherein forming the plurality of carbon nanotube columns comprises:

forming a dielectric layer over the first optical substrate;

forming a template layer over the dielectric layer;

etching the template layer to form a plurality of through holes extending completely through the template layer;

depositing a seed layer over exposed portions of the dielectric layer within the plurality of vias; and

the seed layer is exposed to a carbon nanotube precursor to form the plurality of carbon nanotube pillars.