Extended reality systems and methods

Abstract

An extended reality display system includes a light source to emit light. The system also includes a waveguide assembly to receive and direct the light. The system further includes a spatial light modulator (SLM) configured to receive the light. The waveguide assembly includes a first waveguide, a second waveguide, and an adhesive layer disposed between and in direct contact with the first and second waveguides.

Description

EXTENDED REALITY SYSTEMS AND METHODSCross-Reference to Related Applications

[0001] This application claims the benefit of priority to U.S. Provisional Patent Application Serial No. 63 / 572,129, entitled “AUGMENTED AND MIXED REALITY SYSTEMS AND METHODS,” and filed on March 29, 2024, the contents of which are hereby expressly and fully incorporated by reference in their entirety, as though set forth in full. This application also expressly and fully incorporates by reference the entirety of each of the following patent applications as though set forth in full: U.S. Utility Patent Application Serial No. 14 / 555,585 filed on November 27, 2014 under attorney docket number ML.20011.00 and entitled “VIRTUAL AND AUGMENTED REALITY SYSTEMS AND METHODS”; U.S. Utility Patent Application Serial No. 14 / 738,877 filed on June 13, 2015 under attorney docket number ML.20019.00 and entitled “METHODS AND SYSTEMS FOR CREATING VIRTUAL AND AUGMENTED REALITY”; U.S. Utility Patent Application Serial No. 15 / 683,677 filed on August 22, 2017 under attorney docket number ML-0341 US and entitled “VIRTUAL, AUGMENTED, and MIXED REALITY SYSTEMS AND METHODS”; U.S. Utility Patent Application Serial No. 16 / 215,477 filed on December 10, 2018 under attorney docket number 101782-013710US-1347331 and entitled “WAVEGUIDE ILLUMINATOR”; and U.S. Utility Patent Application Serial No. 17 / 705,202 filed on March 25, 2022 under attorney docket number 101782-013300US-1298503 and entitled “METHOD AND SYSTEM FOR VARIABLE OPTICAL THICKNESSWAVEGUIDES FOR AUGMENTED REALITY DEVICES”.Copyright Notice

[0002] A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.Field of the Invention

[0003] The present disclosure relates to extended reality imaging, visualization, and display systems and methods. In particular, the present disclosure relates to waveguide assemblies for use with display systems.Background

[0004] Modern computing and display technologies have facilitated the development of virtual reality (“VR”), augmented reality (“AR”), mixed reality (“MR”), and extended reality (“XR”) systems. VR systems create a simulated environment for a user to experience. This can be done by presenting computer-generated imagery to the user through a head-mounted display. This imagery creates a sensory experience which immerses the user in the simulated environment. A VR scenario typically involves presentation of only computer-generated imagery rather than also including actual real- world imagery.

[0005] AR systems generally supplement a real-world environment with simulated elements. For example, AR systems may provide a user with a view of the surrounding real-world environment via a head-mounted display. However, computer-generatedimagery can also be presented on the display to enhance the real-world environment. This computer-generated imagery can include elements which are contextually-related to the real-world environment. Such elements can include simulated text, images, objects, etc. MR systems also introduce simulated objects into a real-world environment, but these objects typically feature a greater degree of interactivity than in AR systems. The simulated elements can often times be interactive in real time. XR systems generally facilitate immersive technologies and includes VR systems, AR systems, and MR systems.

[0006] Figure 1 depicts an example AR / MR / XR scene 1 where a user sees a real- world park setting 6 featuring people, trees, buildings in the background, and a concrete platform 20. In addition to these items, computer-generated imagery is also presented to the user. The computer-generated imagery can include, for example, a robot statue 10 standing upon the real-world platform 20, and a cartoon-like avatar character 12 flying by which seems to be a personification of a bumble bee, even though these elements 12, 10 are not actually present in the real-world environment.

[0007] Various optical systems generate images at various depths for displaying VR, AR, MR, or XR scenarios. Some such optical systems are described in U.S. Utility Patent Application Serial No. 14 / 555,585, the contents of which have been previously incorporated by reference herein. Other such optical systems for displaying MR experiences are described in U.S. Utility Patent Application Serial No. 14 / 738,877, the contents of which have been previously incorporated by reference herein.

[0008] Because the human visual perception system is complex, it is challenging to produce a VR / AR / MR / XR technology that facilitates a comfortable, natural-feeling, richpresentation of virtual image elements amongst other virtual or real-world imagery elements. VR / AR / MR / XR technology also has mass, size and portability issues, and other system and optical challenges. Some VR / AR / MR / XR display systems include single waveguides with high index glass to achieve desired optical characteristics, which can lead to fragility issues in the VR / AR / MR / XR display systems. Such VR / AR / MR / XR display systems may not survive drop or shock testing. The systems and methods described herein are configured to address at least some of these and other challenges.

[0009] What is needed is a technique or techniques to improve over legacy techniques and / or over other considered approaches. Some of the approaches described in this background section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued.Summary

[0010] Embodiments are directed to VR, AR, MR, or XR systems and methods. In particular, the embodiments are directed to VR, AR, MR, or XR systems and methods for guiding light with high index waveguides in display systems while maximizing robustness / ruggedness and minimizing mass and size of the waveguides / display systems. Such light sources will be referred herein as “light sources”.

[0011] In one embodiment, an extended reality display system includes a light source to emit light. The system also includes a waveguide assembly to receive and direct the light. The system further includes a spatial light modulator (SLM) configured to receive the light. The waveguide assembly includes a first waveguide, a second waveguide, andan adhesive layer disposed between and in direct contact with the first and second waveguides.

[0012] In one or more embodiments, the first waveguide includes a first in-coupling optical element disposed on a second surface of the first waveguide, and a first out- coupling optical element disposed on a first surface of the first waveguide. The second surface is opposite of the first surface. The adhesive layer is in direct contact with the second surface of the first waveguide. The second waveguide may include a second incoupling optical element and a second out-coupling optical element disposed on a second surface of the second waveguide, and a first surface disposed opposite of the second surface. The adhesive layer may be in direct contact with the first surface of the second waveguide.

[0013] In one or more embodiments, the first out-coupling optical element includes a first plurality of diffractive optical elements having a first variable pitch increasing from a first end of the waveguide assembly to a second end of the waveguide assembly. The first end of the waveguide assembly is opposite of the second end of the waveguide assembly. The second out-coupling optical element may include a second plurality of diffractive optical elements having a second variable pitch increasing from the second end of the waveguide assembly to the first end of the waveguide assembly.

[0014] In one or more embodiments, the first waveguide has a first variable thickness increasing from a first end of the waveguide assembly to a second end of the waveguide assembly. The first end of the waveguide assembly is opposite of the second end of the waveguide assembly. The second waveguide may have a second variable thickness increasing from the second end of the waveguide assembly to the first end of thewaveguide assembly. The first out-coupling optical element may include a first plurality of diffractive optical elements having a first constant pitch. The second out-coupling optical element may include a second plurality of diffractive optical elements having a second constant pitch.

[0015] In one or more embodiments, the first waveguide is configured to direct light of a first color. The second waveguide may be configured to direct light of a second color and a third color. The adhesive layer may include a structural support layer including a plurality of structural support elements imprinted onto an inner surface of the second waveguide.

[0016] In another embodiment, an extended reality display system includes a light source to emit light. The system also includes a waveguide to receive and direct the light. The system further includes a spatial light modulator (SLM) configured to receive the light. The waveguide includes a first plurality of diffractive optical elements disposed on a first surface of the waveguide, and a second plurality of diffractive optical elements disposed on a second surface of the waveguide. The first surface of the waveguide is opposite of the second surface of the waveguide. The first plurality of diffractive optical elements has a first variable pitch increasing from a first end of the waveguide to a second end of the waveguide. The second plurality of diffractive optical elements has a second variable pitch increasing from the second end of the waveguide to the first end of the waveguide. The first end of the waveguide is opposite of the second end of the waveguide.

[0017] The aforementioned and other embodiments of the invention are described in the Detailed Description which follows.Brief Description of the Drawings

[0018] The drawings illustrate the design and utility of various embodiments of the present disclosure. The drawings are not intended to limit the scope of the present disclosure. It should be noted that the figures are not drawn to scale and that elements of similar structures or functions are represented by like reference numerals throughout the figures. In order to better appreciate how to obtain the recited and other advantages and objects of various embodiments of the disclosure, a more detailed description of the present disclosure will be rendered by reference to specific embodiments thereof, which are illustrated in the accompanying drawings. Understanding that these drawings depict only typical embodiments of the disclosure and are not therefore to be considered limiting of its scope, the disclosure will be described and explained with additional specificity and detail through the use of the accompanying drawings.

[0019] Figure 1 depicts a user’s view of an AR / MR / XR scene using an exemplary AR / MR / XR system, according to some embodiments.

[0020] Figure 2 depicts an example of wearable display system, according to some embodiments.

[0021] Figure 3 is a block diagram depicting an AR / MR / XR system, according to some embodiments.

[0022] Figure 4A depicts a conventional display system for simulating three- dimensional imagery for a user.

[0023] Figure 4B depicts aspects of an approach for simulating three-dimensional imagery using multiple depth planes, according to some embodiments.

[0024] Figures 5A-5C depict relationships between radius of curvature and focal radius.

[0025] Figure 6 depicts an example of a waveguide stack for outputting image information to a user, according to some embodiments.

[0026] Figure 7 depicts an example of exit beams outputted by a waveguide, according to some embodiments.

[0027] Figure 8 depicts an example design of a waveguide stack in which each depth plane has three associated waveguides that each output light of a different color, according to some embodiments.

[0028] Figure 9 depicts a system for presenting images to a user’s eye, and for viewing the world, according to some embodiments.

[0029] Figures 10 to 21 D depict waveguide assemblies for use with systems for presenting images to a user’s eye, according to some embodiments.

[0030] Figure 22 depicts a waveguide for use with systems for presenting images to a user’s eye, according to some embodiments.

[0031] Figure 23 is a block diagram schematically depicting an illustrative computing system, according to some embodiments.Detailed Description

[0032] Various embodiments of the disclosure are directed to systems, methods, and articles of manufacture for VR / AR / MR / XR in a single embodiment or in multiple embodiments. Other objects, features, and advantages of the disclosure are described in the detailed description, figures, and claims.

[0033] Various embodiments will now be described in detail with reference to the drawings, which are provided as illustrative examples so as to enable those skilled in the art to practice the disclosure. Notably, the figures and the examples below are not meant to limit the scope of the present disclosure. Where certain elements of the present disclosure may be partially or fully implemented using known components (or methods or processes), only those portions of such known components (or methods or processes) that are necessary for an understanding of the present disclosure will be described, and the detailed descriptions of other portions of such known components (or methods or processes) will be omitted so as not to obscure the disclosure. Further, various embodiments encompass present and future known equivalents to the components referred to herein by way of illustration.

[0034] Embodiments in accordance with the present disclosure address the problem of implementation of VR / AR / MR / XR systems often rely on combinations of off-the-shelf- components and custom components. In some cases the off-the-shelf components do not possess all of the features or performance characteristics that are needed to implement certain desired aspects of the to-be-deployed VR / AR / MR / XR system. Some embodiments are directed to approaches for adding capabilities and / or repurposing resources to accommodate the desired features or performance characteristics of the to- be-deployed VR / AR / MR / XR system. The accompanying figures and discussions herein present example environments, systems, methods, and computer program products for VR / AR / MR / XR systems.Overview

[0035] VR, AR, MR, and XR systems disclosed herein can include a display which presents computer-generated imagery (video / image data) to a user. In some embodiments, the display systems are wearable, which may advantageously provide a more immersive VR / AR / MR / XR experience. Figure 2 illustrates an example of wearable VR / AR / MR / XR display system 80 (hereinafter referred to as “system 80”). The system 80 includes a display 62, and various mechanical and electronic modules and systems to support the functioning of the display 62. The display 62 may be coupled to a frame 64, which is wearable by a display system user or viewer 60 (hereinafter referred to as “user 60”) and which is configured to position the display 62 in front of the eyes of the user 60. In some embodiments, a speaker 66 is coupled to the frame 64 and positioned adjacent the ear canal of the user 60. In some embodiments, another speaker, not shown, is positioned adjacent the other ear canal of the user 60 to provide for stereo / shapeable sound control. The display 62 is operatively coupled, such as by a wired or wireless connection 68, to a local processing and data module 70 which may be mounted in a variety of configurations, such as fixedly attached to the frame 64, fixedly attached to a helmet or hat worn by the user, embedded in headphones, or otherwise removably attached to the user 60 (e.g., in a backpack-style configuration, in a belt-coupling style configuration, etc.).

[0036] The local processing and data module 70 may include a processor, as well as digital memory, such as non-volatile memory (e.g., flash memory), both of which may be utilized to assist in the processing and storing of data. This includes data captured from sensors, such as ambient light sensors (“ALS”), image capture devices (e.g., cameras),microphones, inertial measurement units, accelerometers, compasses, GPS units, radio devices, antenna arrays, depth sensors, and / or gyros. An ALS may be configured to provide light data for processors and algorithms for display control. The sensors may be operatively coupled to the frame 64 or otherwise attached to the user 60. Alternatively, or additionally, sensor data may be acquired and / or processed using a remote processing module 72 and / or a remote data repository 74, possibly for passage to the display 62 after such processing or retrieval. The local processing and data module 70 may be operatively coupled by communication links (76, 78), such as via a wired or wireless communication links, to the remote processing module 72 and remote data repository 74 such that these remote modules (72, 74) are operatively coupled to each other and available as resources to the local processing and data module 70.

[0037] In some embodiments, the remote processing module 72 may include one or more processors configured to analyze and process data (e.g., sensor data and / or image information). In some embodiments, the remote data repository 74 may include a digital data storage facility, which may be available through the internet or other networking configuration in a “cloud” resource configuration. In some embodiments, all data is stored and all computations are performed in the local processing and data module, allowing fully autonomous use from a remote module.

[0038] In some embodiments, the computer-generated image data provided via the display 62 can create the impression of being three-dimensional. This can be done, for example, by presenting stereoscopic image data to the user 60. In some conventional systems, such image data can include separate images of a scene or object from slightly different perspectives. The separate images can be presented to the right eye and lefteye of the user 60, respectively, thus simulating binocular vision and its associated depth perception.

[0039] Referring now to Figure 3, an exemplary embodiment of an AR or MR system 3300 (hereinafter referred to as “system 3300”) is illustrated. The system 3300 uses stacked light guiding optical element (hereinafter referred to as ““LOEs 3390”). The system 3300 generally includes an image generating processor 3310, a light source 3320, a controller / driver 3330, a spatial light modulator (“SLM”) 3340, and at least one set of stacked LOEs 3390 that functions as a multiple plane focus system. The system 3300 may also include an eye-tracking subsystem 3350. It should be appreciated that other embodiments may have multiple sets of stacked LOEs 3390.

[0040] The image generating processor 3310 is configured to generate virtual content to be displayed to the user. The image generating processor 3310 may convert an image or video associated with the virtual content to a format that can be projected to the user in 3D. For example, in generating 3D content, the virtual content may need to be formatted such that portions of a particular image are displayed at a particular depth plane while others are displayed at other depth planes. In one embodiment, all of the image may be generated at a particular depth plane. In another embodiment, the image generating processor 3310 may be programmed to provide slightly different images to the right and left eyes such that when viewed together, the virtual content appears coherent and comfortable to the user’s eyes.

[0041] The image generating processor 3310 may further include a memory 3312, a GPU 3314, a CPU 3316, and other circuitry for image generation and processing. The image generating processor 3310 may be programmed with the desired virtual content tobe presented to the user of the system 3300. It should be appreciated that in some embodiments, the image generating processor 3310 may be housed in the system 3300. In other embodiments, the image generating processor 3310 and other circuitry may be housed in a belt pack that is coupled to the system 3300.

[0042] The image generating processor 3310 is operatively coupled to the light source 3320 which projects light associated with the desired virtual content and one or more spatial light modulators 3340. The image generating processor 3310 and / or the controller / driver 3330 may also calibrate and correct for system nonuniformities. For example, EP nonuniformities or segmented illumination nonuniformities, which result from exposure to high temperatures and aging. The image generating processor 3310 may also warp / transform images with low latencies to account for user motions. The light source 3320 is compact and has high resolution.

[0043] The light source 3320 is operatively coupled to the controller / driver 3330. The light source 3320 may be connected to the controller / driver 3330 in various embodiments. In some embodiments, the light source 3320 and the controller / driver 3330 are co-located on the same board. Those versed in the art would appreciate the value of minimizing the effect of cable inductance and capacitance by co-locating light sources to “driver” electronics. Minimizing the impact of coupled inductance and capacitance by co-locating the light source 3320 and the controller / driver 3330 facilitates faster transition (i.e. , “ON” to “OFF” and all the intervening dimming levels) of the light source 3320. In embodiments in which the light source 3320 and the controller / driver 3330 are located farther away from each other, the stray inductance and capacitance resulting from the increased distancebetween the light source 3320 and the controller / driver 3330 may be managed by proper cable construction, such as that used in a Flex cable, which can provide shielding.

[0044] The light source 3320 is coupled to the controller / driver 3330 electrically to allow the controller / driver 3330 to drive the light source 3320. The controller / driver 3330 can also connect to both the image generating processor 3310 and the SLM 3340 electrically to facilitate coordinated control. The image generating processor 3310 may send the processed illumination array data (gray values for each color) to the controller / driver 3330. The SLM 3340 may send timing signals to the controller / driver 3330 to facilitate the illumination at the appropriate time(s). In some embodiments, electronically connecting the controller / driver 3330 to the SLM 3340 enables the light source 3320 to emit the correct LED colors when the SLM 3340 is refreshing a color field for a field sequential display system.

[0045] The light source 3320 may be include color specific light emitting diodes (“LEDs”) disposed in various geometric configurations. Alternatively, the light source 3320 may include LEDs of like color, each one linked to a specific region of the field of view of the display. In some embodiments, the light source 3320 may include mini LEDs, micro LEDs, laser diodes, phosphor converted LED sources, vertical-cavity surfaceemitting laser (“VSCELs”), and / or super luminescent diodes (“SLDs”). In some embodiments, the light source 3320 may include a mask overlay for segmentation of emission areas and positions. Although the light source 3320 is directly connected to the system 3300 in Figure 3, the light source 3320 may be connected to the system 3300 via optical fibers (not shown). The system 3300 may also include condenser (not shown) configured to collimate the light from the light source 3320.

[0046] The SLM 3340 may be reflective (e.g., an LCOS, an FLCOS, a DLP DMD, or a MEMS mirror system) or transmissive (e.g., an LCD) in various exemplary embodiments. The type of SLM 3340 (e.g., speed, size, etc.) can be selected to improve the creation of the 3D perception. While DLP DMDs operating at higher refresh rates may be easily incorporated into stationary systems 3300, wearable systems 3300 may use DLPs of smaller size and power. The power of the DLP changes how 3D depth planes / focal planes are created. The image generating processor 3310 is operatively coupled to the SLM 3340, which encodes the light from the light source 3320 with the desired virtual content. Light from the light source 3320 may be encoded with the image information when it reflects off of, emits from, or passes through the SLM 3340.

[0047] Light from the SLM 3340 is directed to the LOEs 3390 such that light beams encoded with image data for one depth plane and / or color by the SLM 3340 are effectively propagated along a single LOE 3390 for delivery to an eye of a user. Each LOE 3390 is configured to project an image or sub-image that appears to originate from a desired depth plane or FOV angular position onto a user’s retina. The light source 3320 and LOEs 3390 can therefore selectively project images (synchronously encoded by the SLM 3340 under the control of controller / driver 3330) that appear to originate from various depth planes or positions in space. By sequentially projecting images using each of the light source 3320 and LOEs 3390 at a sufficiently high frame rate (e.g., 360 Hz for six depth planes at an effective full-volume frame rate of 60 Hz), the system 3300 can generate a 3D image of virtual objects at various depth planes that appear to exist simultaneously in the 3D image.

[0048] The controller / driver 3330 is in communication with and operatively coupled to the image generating processor 3310, the light source 3320 and the SLM 3340 to coordinate the synchronous display of images by instructing the SLM 3340 to encode the light beams from the light source 3320 with appropriate image information from the image generating processor 3310.

[0049] The system 3300 also includes an optional eye-tracking subsystem 3350 that is configured to track the user’s eyes and determine the user’s focus. In one embodiment, the system 3300 is configured to illuminate a subset of LOEs 3390, based on input from the eye-tracking subsystem 3350 such that the image is generated at a desired depth plane that coincides with the user’s focus / accommodation. For example, if the user’s eyes are parallel to each other, the system 3300 may illuminate the LOE 3390 that is configured to deliver collimated light to the user’s eyes, such that the image appears to originate from optical infinity. In another example, if the eye-tracking subsystem 3350 determines that the user’s focus is at 1 meter away, the LOE 3390 that is configured to focus approximately within that range may be illuminated instead.

[0050] Figure 4A illustrates a conventional display system for simulating three- dimensional image data to a user (e.g., the user 60). Two distinct images 84 and 86, one for each eye 4 and 5, are outputted to the user. The images 84 and 86 are spaced from the eyes 4 and 5 by a distance 12 along an optical or z-axis parallel to the line of sight of the user 60. The images 84 and 86 are flat and the eyes 4 and 5 may focus on the images by assuming a single accommodated state. Such systems rely on the human visual system to combine the images 84 and 86 to provide a perception of depth for the combined image.

[0051] It will be appreciated, however, that the human visual system is more complicated and providing a realistic perception of depth is more challenging. For example, many users of conventional 3D display systems find such systems to be uncomfortable or may not perceive a sense of depth at all. Without being limited by theory, it is believed that users viewing an object may perceive the object as being “three- dimensional” due to a combination of vergence and accommodation. Vergence movements (i.e., rolling movements of the pupils toward or away from each other to converge the lines of sight of the eyes to fixate upon an object) of the two eyes relative to each other are closely associated with focusing (or “accommodation”) of the lenses of the eyes. Under normal conditions, changing the focus of the lenses of the eyes, or accommodating the eyes, to change focus from one object to another object at a different distance will automatically cause a matching change in vergence to the same distance, under a relationship known as the “accommodation-vergence reflex.” Likewise, a change in vergence will trigger a matching change in accommodation, under normal conditions. As noted herein, many stereoscopic display systems display a scene using slightly different presentations (and, so, slightly different images) to each eye such that a three- dimensional perspective is perceived by the human visual system. Such systems are uncomfortable for many users since they simply provide different presentations of a scene but with the eyes viewing all the image information at a single accommodated state, and thus work against the accommodation-vergence reflex. Systems that provide a better match between accommodation and vergence may form more realistic and comfortable simulations of three-dimensional image data.

[0052] For example, light field video data can be presented to the user to simulate a three-dimensional view. Light field video data can mimic the rays of light which enter the eyes of the user 60 in a real-world environment. For example, when displaying light field video data, light rays from objects that are simulated to be perceived at a distance are made to be more collimated when entering the eyes of the user, while light rays from objects that are simulated to be perceived nearby are made to be more divergent. Thus, the angles at which light rays from objects in a scene enter the eyes of the user are dependent upon the simulated distance of those objects from the viewer. Light field video data in a VR / AR / MR / XR system can include multiple images of a scene or object from different depth planes. The images may be different for each depth plane (e.g., one depth plane may include imagery corresponding to the foreground of a scene, while another depth plane includes imagery corresponding to the background of the scene) and may be separately focused by the viewer’s eyes, thereby helping to provide the user with a comfortable perception of depth.

[0053] When these multiple depth plane images are presented to the viewer simultaneously or in quick succession, the result is interpreted by the viewer as three- dimensional imagery. When the viewer experiences this type of light field video data, the eyes accommodate to focus the different depth planes in much the same way as they would do when experiencing a real-world scene. These focal cues can provide for a more realistic simulated three-dimensional environment.

[0054] In some configurations, at each depth plane, a full color image may be formed by overlaying component images that each have a particular component color. For example, red, green, and blue images may each be separately outputted to form each fullcolor depth plane image. As a result, each depth plane may have multiple component color images associated with it.

[0055] Figure 4B illustrates aspects of an approach for simulating three-dimensional imagery using multiple depth planes. Objects at various distances from eyes 4 and 5 on the z-axis are accommodated by the eyes (4, 5) so that those objects are in focus. The eyes 4 and 5 assume particular accommodated states to bring into focus objects at different distances along the z-axis. Consequently, a particular accommodated state may be said to be associated with a particular one of depth planes 14, such that objects or parts of objects in a particular depth plane are in focus when the eye is in the accommodated state for that depth plane. In some embodiments, three-dimensional image data may be simulated by providing different presentations of the image data for each of the eyes (4, 5), and also by providing different presentations of the image data corresponding to each of the depth planes.

[0056] The distance between an object and the eye (4 or 5) can change the amount of divergence of light from that object, as viewed by that eye. Figures 5A-5C illustrate relationships between distance and the divergence of light rays. The distance between the object and the eye 4 is represented by, in order of decreasing distance, R1 , R2, and R3. As shown in Figures 5A-5C, the light rays become more divergent as distance from the eye 4 to the object decreases. As distance from the eye 4 to the object increases, the light rays become more collimated. Stated another way, it may be said that the light field produced by a point (the object or a part of the object) has a spherical wavefront curvature, which is a function of how far away the point is from the eye 4 of the user. The curvature increases with decreasing distance between the object and the eye 4.Consequently, at different depth planes, the degree of divergence of light rays is also different, with the degree of divergence increasing with decreasing distance between depth planes and the eye 4. While only a single eye 4 is illustrated for clarity of illustration in Figures 5A-5C and other figures herein, it will be appreciated that the discussions regarding eye 4 may be applied to both eyes (4 and 6) of a viewer.

[0057] Without being limited by theory, it is believed that the human eye typically can interpret a finite number of depth planes to provide depth perception. Consequently, a highly believable simulation of perceived depth may be achieved by providing, to the eye, different presentations of image data corresponding to each of these limited number of depth planes.

[0058] Figure 6 illustrates an example of a waveguide stack for outputting image data to a user (e.g., the user 60). A display system 1000 includes a stack of waveguides, or stacked waveguide assembly 178, that may be utilized to provide three-dimensional perception to the eye / brain using one or more waveguides (182, 184, 186, 188, 190). In some embodiments, the display system 1000 is the system 80 of Figure 2, with Figure 6 schematically showing some parts of the system 80 in greater detail. For example, the stacked waveguide assembly 178 may be integrated into the display 62 of Figure 2.

[0059] The stacked waveguide assembly 178 may also include one or more features (198, 196, 194, 192) between the waveguides. In some embodiments, the features (198, 196, 194, 192) may be lenses. The waveguides (182, 184, 186, 188, 190) and / or the lenses (198, 196, 194, 192) may be configured to send image data to the eye with various levels of wavefront curvature or light ray divergence. Each waveguide level may be associated with a particular depth plane and may be configured to output image datacorresponding to that depth plane. Image injection devices (200, 202, 204, 206, 208) may be utilized to inject image data into the waveguides (182, 184, 186, 188, 190), each of which may be configured, as described herein, to distribute incoming light across each respective waveguide, for output toward the eye 4. Light exits an output surface (300, 302, 304, 306, 308) of the image injection devices (200, 202, 204, 206, 208) and is injected into a corresponding input edge (382, 384, 386, 388, 390) of the waveguides (182, 184, 186, 188, 190). In some embodiments, a single beam of light (e.g., a collimated beam) may be injected into each waveguide to output an entire field of cloned collimated beams that are directed toward the eye 4 at particular angles (and amounts of divergence) corresponding to the depth plane associated with a particular waveguide.

[0060] In some embodiments, the image injection devices (200, 202, 204, 206, 208) are discrete displays that each produce image data for injection into a corresponding waveguide (182, 184, 186, 188, 190, respectively). In some other embodiments, the image injection devices (200, 202, 204, 206, 208) are the output ends of a single multiplexed display which may pipe image data via one or more optical conduits (such as fiber optic cables) to each of the image injection devices (200, 202, 204, 206, 208).

[0061] A controller 210 controls the operation of the stacked waveguide assembly 178 and the image injection devices (200, 202, 204, 206, 208). In some embodiments, the controller 210 includes programming (e.g., instructions in a non-transitory computer- readable medium) that regulates the timing and provision of image data to the waveguides (182, 184, 186, 188, 190) according to any of the various schemes disclosed herein. In some embodiments, the controller 210 may be a single integral device, or a distributed system connected by wired or wireless communication channels. Thecontroller 210 may be part of a processing module (e.g., the local processing and data module 70 and / or the remote processing module 72 of Figure 2) in some embodiments.

[0062] The waveguides (182, 184, 186, 188, 190) may be configured to propagate light within each respective waveguide by total internal reflection (TIR). The waveguides (182, 184, 186, 188, 190) may each be planar or curved, with major top and bottom surfaces and edges extending between those major top and bottom surfaces. In the illustrated configuration, the waveguides (182, 184, 186, 188, 190) may each include light redirecting elements (282, 284, 286, 288, 290) that are configured to redirect light, propagating within each respective waveguide, out of the waveguide to output image data to the eye 4. A beam of light is outputted by the waveguide at locations at which the light propagating in the waveguide strikes a light redirecting element. The light redirecting elements (282, 284, 286, 288, 290) may be reflective and / or diffractive optical features. While illustrated disposed at the bottom major surfaces of the waveguides (182, 184, 186, 188, 190) for ease of description and drawing clarity, in some embodiments, the light redirecting elements (282, 284, 286, 288, 290) may be disposed at the top and / or bottom major surfaces, and / or may be disposed directly in the volume of the waveguides (182, 184, 186, 188, 190). In some embodiments, the light redirecting elements (282, 284, 286, 288, 290) may be formed in a layer of material that is attached to a transparent substrate to form the waveguides (182, 184, 186, 188, 190). In some other embodiments, the waveguides (182, 184, 186, 188, 190) may be a monolithic piece of material and the light redirecting elements (282, 284, 286, 288, 290) may be formed on a surface and / or in the interior of that piece of material.

[0063] As discussed herein, each waveguide (182, 184, 186, 188, 190) is configured to output light to form an image corresponding to a particular depth plane. For example, the waveguide 182 nearest the eye 4 may be configured to deliver collimated light, as injected into such waveguide 182, to the eye 4. The collimated light may be representative of the optical infinity focal plane. The next waveguide up 184 may be configured to send out collimated light which passes through the first lens 192 (e.g., a negative lens) before it can reach the eye 4. The first lens 192 may be configured to create a slight convex wavefront curvature so that the eye / brain interprets light coming from that next waveguide up 184 as coming from a first focal plane closer inward toward the eye 4 from optical infinity. Similarly, the third waveguide up 186 passes its output light through both the first lens 192 and second lens 194 before reaching the eye 4; the combined optical power of the first lens 192 and second lens 194 may be configured to create another incremental amount of wavefront curvature so that the eye / brain interprets light coming from the third waveguide 186 as coming from a second focal plane that is even closer inward toward the user from optical infinity than was light from the next waveguide up 184.

[0064] The other waveguides (188, 190) and lenses (196, 198) are similarly configured, with the highest waveguide 190 in the stack sending its output through all of the lenses between it and the eye for an aggregate focal power representative of the closest focal plane to the user. To compensate for the stack of lenses (198, 196, 194, 192) when viewing / interpreting light coming from world 144 on the other side of the stacked waveguide assembly 178, a compensating lens layer 180 may be disposed at the top of the stacked waveguide assembly 178 to compensate for the aggregate powerof the lens stack (198, 196, 194, 192) below. Such a configuration provides as many perceived focal planes as there are available waveguide / lens pairings. Both the light redirecting elements of the waveguides and the focusing aspects of the lenses may be static (i.e., not dynamic or electro-active). In some alternative embodiments, they may be dynamic using electro-active features.

[0065] The light redirecting elements (282, 284, 286, 288, 290) may be configured to both redirect light out of their respective waveguides and to output this light with the appropriate amount of divergence or collimation for a particular depth plane associated with the waveguide. As a result, waveguides having different associated depth planes may have different configurations of light redirecting elements (282, 284, 286, 288, 290), which output light with a different amount of divergence depending on the associated depth plane. In some embodiments, as discussed herein, the light redirecting elements (282, 284, 286, 288, 290) may be volumetric or surface features, which may be configured to output light at specific angles. For example, the light redirecting elements (282, 284, 286, 288, 290) may be volume holograms, surface holograms, and / or diffraction gratings. Light redirecting elements, such as diffraction gratings, are described in U.S. Patent Application No. 14 / 641 ,376, filed March 7, 2015, which is incorporated by reference herein in its entirety. In some embodiments, the features (198, 196, 194, 192) may not be lenses; rather, they may simply be spacers (e.g., cladding layers and / or structures for forming air gaps).

[0066] In some embodiments, the light redirecting elements (282, 284, 286, 288, 290) are diffractive features that form a diffraction pattern, or “diffractive optical element” (also referred to herein as a “DOE”). Preferably, the DOE’s have a relatively low diffractionefficiency so that only a portion of the light of the beam is deflected away toward the eye 4 with each intersection of the DOE, while the rest continues to move through a waveguide via total internal reflection. The light carrying the image data is thus divided into a number of related exit beams that exit the waveguide at a multiplicity of locations and the result is a fairly uniform pattern of exit emission toward the eye 4 for this particular collimated beam reflecting around within a waveguide.

[0067] In some embodiments, one or more DOEs may be switchable between “on” states in which they actively diffract, and “off” states in which they do not significantly diffract. For instance, a switchable DOE may include a layer of polymer dispersed liquid crystal, in which microdroplets include a diffraction pattern in a host medium, and the refractive index of the microdroplets can be switched to substantially match the refractive index of the host material (in which case the pattern does not appreciably diffract incident light) or the microdroplet can be switched to an index that does not match that of the host medium (in which case the pattern actively diffracts incident light).

[0068] Figure 7 shows an example of exit beams outputted by a waveguide. One waveguide is illustrated, but it will be appreciated that other waveguides in the stacked waveguide assembly 178 may function similarly. Light 400 is injected into the waveguide 182 at the input edge 382 of the waveguide 182 and propagates within the waveguide 182 by TIR. At points where the light 400 impinges on the DOE 282, a portion of the light exits the waveguide as exit beams 402. The exit beams 402 are illustrated as substantially parallel but, as discussed herein, they may also be redirected to propagate to the eye 4 at an angle (e.g., forming divergent exit beams), depending on the depth plane associated with the waveguide 182. It will be appreciated that substantially parallelexit beams may be indicative of a waveguide that corresponds to a depth plane at a large simulated distance (e.g., optical infinity) from the eye 4. Other waveguides may output an exit beam pattern that is more divergent, which would require the eye 4 to accommodate to focus on a closer simulated distance and would be interpreted by the brain as light from a distance closer to the eye 4 than optical infinity.

[0069] Figure 8 schematically illustrates an example design of a stacked waveguide assembly (e.g., the stacked waveguide assembly 178) in which each depth plane has three associated waveguides that each output light of a different color. A full color image may be formed at each depth plane by overlaying images in each of multiple component colors (e.g., three or more component colors). In some embodiments, the component colors include red, green, and blue. In some other embodiments, other colors, including magenta, yellow, and cyan, may be used in conjunction with or may replace one of red, green, or blue. Each waveguide may be configured to output a particular component color and, consequently, each depth plane may have multiple waveguides associated with it. Each depth plane may have three waveguides associated with it: a first for outputting red light, a second for outputting green light, and a third for outputting blue light.

[0070] Depth planes 14a-14f are shown in Figure 8. In the illustrated embodiment, each depth plane has three component color images associated with it: a first image of a first color, G; a second image of a second color, R; and a third image of a third color, B. The numbers following each of these letters indicate diopters (1 / m), or the reciprocal of the apparent distance of the depth plane from a viewer, and each box in the figures represents an individual component color image. In some embodiments, G is the colorgreen, R is the color red, and B is the color blue. As discussed above, the perceived distance of the depth plane from the user may be established by the light redirecting elements (282, 284, 286, 288, 290) (e.g., diffractive optical element (DOE), and / or by lenses (198, 196, 194, 192)) which cause the light to diverge at an angle associated with the apparent distance.

[0071] In some arrangements, each component color image may be outputted by a different waveguide in a stack of waveguides. For example, each depth plane may have three component color images associated with it: a first waveguide to output a first color, G; a second waveguide to output a second color, R; and a third waveguide to output a third color, B. In arrangements in which waveguides are used to output component color images, each box in Figure 8 may be understood to represent an individual waveguide.

[0072] While the waveguides associated with each depth plane are shown adjacent to one another in this schematic drawing for ease of description, it will be appreciated that, in a physical device, the waveguides may all be arranged in a stack with one waveguide per level. Different depth planes are indicated in the figure by different numbers for diopters following the letters G, R, and B.Definitions and Use of Figures

[0073] Some of the terms used in this description are defined below for reference. The presented terms and their respective definitions are not rigidly restricted to these definitions — a term may be further defined by the term’s use within this disclosure. The term “exemplary” is used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects or designs. Rather, use of the wordexemplary is intended to present concepts in a concrete fashion. As used in this application and the appended claims, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or”. That is, unless specified otherwise, or is clear from the context, “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, if X employs A, X employs B, or X employs both A and B, then “X employs A or B” is satisfied under any of the foregoing instances. As used herein, at least one of A or B means at least one of A, or at least one of B, or at least one of both A and B. In other words, this phrase is disjunctive. The articles “a” and “an” as used in this application and the appended claims should generally be construed to mean “one or more” unless specified otherwise or is clear from the context to be directed to a singular form.

[0074] Various embodiments are described herein with reference to the figures. It should be noted that the figures are not necessarily drawn to scale and that elements of similar structures or functions are sometimes represented by like reference characters throughout the figures. It should also be noted that the figures are only intended to facilitate the description of the disclosed embodiments — they are not representative of an exhaustive treatment of all possible embodiments, and they are not intended to impute any limitation as to the scope of the claims. In addition, an illustrated embodiment need not portray all aspects or advantages of usage in any particular environment.

[0075] An aspect or an advantage described in conjunction with a particular embodiment is not necessarily limited to that embodiment and can be practiced in any other embodiments even if not so illustrated. References throughout this specification to “some embodiments” or “other embodiments” refer to a particular feature, structure, material or characteristic described in connection with the embodiments as being includedin at least one embodiment. Thus, the appearance of the phrases “in some embodiments” or “in other embodiments” in various places throughout this specification are not necessarily referring to the same embodiment or embodiments. The disclosed embodiments are not intended to be limiting of the claims.Exemplary Display Systems and Waveguides

[0076] Figure 9 depicts a system (e.g., an AR display system) 900 for presenting images to the user's eye 902 and for viewing the world 904 according to some embodiments. The system 900 includes a light source 910, a spatial light modulator (SLM) 940, and a waveguide assembly 920 arranged such that light from the light source 910 illuminates the SLM 940, and light reflected from the SLM 940 is coupled into the waveguide assembly 920 to be directed to the eye 902. The system 900 includes optics 930 disposed to both illuminate at least a portion of the SLM 940 and project an image of the SLM 940. Light from the light source 910, for example, propagates in a first direction through the optics 930 onto at least a portion of the SLM 940 thereby illuminating at least a portion of the SLM 940. Light reflected from the SLM 940 propagates again through the optics 930 in a second direction opposite the first direction and is directed to the waveguide assembly 920 and coupled therein.

[0077] The light source 910 may include an array of independently addressable / operable LEDs or other types of light sources in an array of independently addressable / operable array. In some embodiments, such as the one depicted in Figure 9, the light source 910 is a 10 x 10 array of LEDs. In other embodiments, the light source 910 can be other arrays having other numbers of LEDs in each direction (e.g., any number greater than 0). While the depicted light source 910 is a square shaped array, othershapes are also within the scope of the disclosure. In various embodiments, subgroups of the LEDs in the array forming the light source 910 are independently addressable / operable. The LEDs may be operable in on / off states or operable at various brightness levels from 0% (off) to 100%. The LEDs may be configured to emit light of one color. While the system 900 depicted in Figure 9 includes a single light source 910, systems according to other embodiments include multiple light sources. In some embodiments, the system includes three light sources, one for each of three colors (e.g., red, green, and blue; purple, cyan, and yellow; or any other colors). In some embodiments, the system includes two light sources, one for a first color or combination of colors (e.g., red) and one for a second color or combination of colors (e.g., green and blue).

[0078] The light source 910 may be a polarized light source, however the light source 910 need not be so limited. In some implementations, a polarizer 915 may be positioned between the light source 910 and the SLM 940. As illustrated, the polarizer 915 is between the light source 910 and the waveguide assembly 920. This polarizer 915 may also be a light recycler, transmitting light of a first polarization and reflecting light of a second polarization back to the light source 910. Such a polarizer 915 may be, for example, a wire grid polarizer. A coupling optic 905, such as a non-imaging optical element (e.g., cone, compound parabolic collector (CPC) or lenses, may be disposed with respect to the light source 910 to receive light output from the light source 910. The coupling optic 905 may collect the light from the light source 910 and may, in some cases, reduce the divergence of light emitted from the light source 910. The coupling optic 905 may, for example, collimate the light output from the light source 910. The coupling optic905 may collect light that matches the angular spectrum field of view of the system 900. Accordingly, the coupling optic 905 may match an angular spectrum of the light output by the light source 910 with the field of view of the system 900. The coupling optic 905 may have an asymmetric profile to operate on the light emitted from the light source 910 asymmetrically. For example, the coupling optic 905 may reduce the divergence a different amount in orthogonal directions (e.g., x and z directions). Such asymmetry in the coupling optic 905 may address asymmetry in the light emitted from the light source 910 which may include, for example, LEDs that emit a wider range of angles of light in one direction (e.g., x or z) as opposed to the orthogonal direction (e.g., z or x, respectively).

[0079] As discussed above, the system 900 includes optics 930 configured to illuminate the SLM 940 that is disposed in an optical path between the light source 910 and the SLM 940. The optics 930 may include transmissive optics that transmits light from the light source 910 to the SLM 940. The optics 930 may also be configured to project an image of the SLM 940 or formed by the SLM 940 into the waveguide assembly 920. An image may be projected into the eye 902 of the user. The optics 930 may include one or more refractive optical elements such as refractive lenses. Other types of optical elements may also possibly be used.

[0080] The SLM 940 may be reflective, modulating and reflecting light therefrom. The SLM 940 may be a polarization based SLM configured to modulate polarization. The SLM 940 may, for example, include a liquid crystal (LC) SLM (e.g., a liquid crystal on silicon (LCOS) SLM). The LCOS SLM may, for example, include twisted nematic (TN) liquid crystal. The SLM 940 may, for example, include one or more pixels that areconfigured to selectively modulate light incident on the pixel depending on the state of the pixel. For some types of SLMs 940, the pixel may, for example, modulate the beam incident thereon by altering the polarization state such as rotating the polarization (e.g., rotating the orientation of linearly polarized light).

[0081] As discussed above, the SLM 940 may be a LCOS SLM 940. In a crosspolarizer configuration, the LCOS SLM 940 may be nominally white. When a pixel is off (e.g., 0 voltage), it has a bright state, and when the pixel is on (e.g., voltage above a threshold turn on voltage), it has a dark state. In this cross-polarization configuration, leakage is minimized when a pixel is on and it has a dark state.

[0082] In a parallel-polarizer configuration, the LCOS SLM 940 is nominally black. When a pixel is off (e.g., 0 voltage), it has a dark state, and when the pixel is on (e.g., voltage above a threshold turn on voltage), it has a bright state. In this parallel-polarizer configuration, leakage is minimized when a pixel is off and it has a dark state. The dark state may be (re)optimized using rub direction and compensator angle. Compensator angle may refer to an angle of a compensator (not shown) which may be between the optics 930 and the SLM 940.

[0083] Dynamic range and throughput for parallel-polarizer configurations may be different than that of cross-polarizer configurations. Further, parallel-polarizer configurations may be optimized for contrast differently than cross-polarizer configurations.

[0084] The system 900 includes a waveguide assembly 920 for outputting image information to the eye 902. The waveguide assembly 920 may include substantially transparent materials having refractive indices sufficient to guide light therein. Asillustrated, the waveguide assembly 920 may include a first side 921 and a second side 923 opposite the first side 921 and corresponding upper and lower major surfaces as well as edges therearound. The first and second major surfaces 921 , 923 may be sufficiently flat such that image information may be retained upon propagating light from the SLM 940 to the eye 902 such than an image formed by the SLM 940 may be injected into the eye 902. The waveguide assembly 920 may include one or more diffractive optical elements configured to have optical power. The diffractive optical element may, for example, have positive optical power. In embodiments where the waveguide assembly 920 has sufficient optical power, the optics 930 may be omitted from the system 900. The optics 930 and the SLM 940 may be positioned on the first side 921 of the waveguide assembly 920. The light source 910 may be disposed on the second side 923 such that light from the light source 910 is incident on the second side 923 prior to passing through the waveguide assembly 920 and through the optics 930 to the SLM 940. Accordingly, the waveguide assembly 920 may be disposed between the light source 910 and the optics 930. Additionally, at least a portion of the waveguide assembly 920 may extend between the light source 910 and the optics 930, whereby light passes through the portion of the waveguide assembly 920 to the optics 930. Light emitted from the light source 910 can therefore be directed through the waveguide assembly 920, into and through the optics 930 and incident on the SLM 940. The SLM 940 reflects the light back through the optics 930 and to the waveguide assembly 920.

[0085] The system 900 also includes two in-coupling optical elements 960, 962 for coupling light from the optics 930 into the waveguide assembly 920. The in-coupling optical elements 960, 962 may be disposed on the major surfaces 921 , 923 of thewaveguide assembly 920. While illustrated on two sides and corners of the waveguide assembly 920, the in-coupling optical element 960 may be disposed in / on other areas of the waveguide assembly 920. For instance, a reflective in-coupling optical element may be disposed on an inner surface of the waveguide assembly 920 (see Figure 10). The in-coupling optical element 960 may be a diffractive optical element or a reflector. Other structures may be used as the in-coupling optical element 960. The in-coupling optical element 960 may be configured to direct the light incident thereon into the waveguide assembly 920 at a sufficiently large grazing angle (e.g., greater than the critical angle) with respect to major surfaces of the waveguide assembly 920 to be guided therein by total internal reflection. Further, the in-coupling optical element 960 may operate on a wide range of wavelengths and thus be configured to couple light of multiple colors into the waveguide assembly 920. For instance, the in-coupling optical element 960 may be configured to couple red light into a first waveguide of the waveguide assembly 920, and the in-coupling optical element 962 may be configured to couple green and blue light into a second waveguide of the waveguide assembly 920. The light source 910 may emit red, green, and blue color light at different times.

[0086] The system 900 includes light distributing elements 970, 972 disposed on or in the waveguide assembly 920. In some embodiments, the light distributing elements 970, 972 may be orthogonal pupil expanders (OPE). The light distributing elements 970, 972 may be configured to spread the light within the waveguide assembly 920 by turning the light propagating in an x direction, for example, toward a z direction. The light distributing elements 970, 972 may, thus, be configured to increase dimensions of the eyebox along the z-axis. The light distributing elements 970, 972 may, for example, include one ormore diffractive optical elements configured to diffract the light propagating within the waveguide assembly 920 incident the diffractive optical elements so as to redirect that light, for example, in a generally orthogonal direction.

[0087] Other configurations are possible. For instance, embodiments with multiple light sources may have multiple waveguide assemblies corresponding to each of the light sources. In such embodiments, each of the multiple waveguide assemblies may have incoupling optical elements that do not overlap with the in-coupling optical elements for the other waveguide assemblies in order to minimize unintended in-coupling into the other waveguide assemblies. In other embodiments, light sources, SLMs, and optics may all be disposed on the same side of the waveguide assembly. In embodiments where the waveguide assembly has sufficient optical power, optics may be omitted from the system.

[0088] Figure 10 depicts in greater detail a waveguide assembly 1000 for use with display systems, such as display system 900 depicted in Figure 9, according to some embodiments. Similar to the waveguide 920 depicted in Figure 9, the waveguide assembly 1000 is configured to direct light 1042 incident thereon from and SLM 1040 to a user’s eye 1002. The waveguide assembly 1000 includes a first waveguide 1010, a second waveguide 1030, and an adhesive layer 1020 disposed between and in direct contact with the first and second waveguides 1010, 1030.

[0089] The adhesive layer 1020 replaces an air gap in conventional waveguide assemblies. The air gap separating waveguides renders conventional waveguide assemblies fragile, and replacing the air gap with an adhesive layer 1020 improves the robustness / ruggedness of the waveguide assembly 1000. Using the adhesive layer 1020 to improve the robustness / ruggedness of the waveguide assembly 1000 allows the firstand second waveguides 1010, 1030 to be formed from materials (e.g., glass) having relatively high indices of refraction (e.g., at least 1.8) while minimizing fragility of the waveguide assembly 1000. The first and second waveguides 1010, 1030 may also be formed from polymers having relatively high refractive indices (e.g., at least 1.7). The adhesive layer 1020 has a lower refractive index (e.g., less than 1.4).

[0090] The first waveguide 1010 has a first surface 1011 facing the SLM 1040 and the user’s eye 1002. The first waveguide 1010 also has a second surface 1013 opposite of the first surface 1011 and facing the adhesive layer 1020. The first waveguide 1010 includes an in-coupling optical element / in-coupling grating 1012. The in-coupling optical element 1012 is reflective and therefore disposed on the inner second surface 1013 of the first waveguide 1010. The first waveguide 1010 also includes an out-coupling optical element / out-coupling grating 1014 disposed on the outer first surface 1011 of the first waveguide 1010. The in-coupling optical element 1012 may be configured to direct the light incident thereon into the first waveguide 1010 at a sufficiently large grazing angle (e.g., greater than the critical angle) with respect to major surfaces of the first waveguide 1010 to be guided therein by total internal reflection. The out-coupling optical element 1014 may be configured to redirect the light propagating within the first waveguide 1010 by turning the light propagating in an x direction, for example, toward a z direction. The out-coupling optical element 1014 may, thus, be configured to increase dimensions of the eyebox along the z-axis. The out-coupling optical element 1014 may, for example, include one or more diffractive optical elements configured to diffract the light propagating within the first waveguide 1010 incident the diffractive optical elements so as to redirectthat light, for example, in a generally orthogonal direction. The redirected light 1016 exits the first waveguide 1010 toward the user’s eye 1002.

[0091] The second waveguide 1030 has a first surface 1031 facing the adhesive layer 1020, the SLM 1040, and the user’s eye 1002. The second waveguide 1030 also has a second surface 1033 opposite of the first surface 1031 and facing away from the adhesive layer 1020. The second waveguide 1030 includes an in-coupling optical element / in- coupling grating 1032. The in-coupling optical element 1032 is reflective and therefore disposed on the outer second surface 1033 of the second waveguide 1030. The second waveguide 1030 also includes an out-coupling optical element / out-coupling grating 1034 disposed on the outer second surface 1033 of the second waveguide 1030. The incoupling optical element 1032 may be configured to direct the light incident thereon into the second waveguide 1030 at a sufficiently large grazing angle (e.g., greater than the critical angle) with respect to major surfaces of the second waveguide 1030 to be guided therein by total internal reflection. The out-coupling optical element 1034 may be configured to redirect the light propagating within the second waveguide 1030 by turning the light propagating in an x direction, for example, toward a z direction. The out-coupling optical element 1034 may, thus, be configured to increase dimensions of the eyebox along the z-axis. The out-coupling optical element 1034 may, for example, include one or more diffractive optical elements configured to diffract the light propagating within the second waveguide 1030 incident the diffractive optical elements so as to redirect that light, for example, in a generally orthogonal direction. The redirected light 1036 exits the second waveguide 1030 toward the user’s eye 1002.

[0092] The first and / or second waveguides 1010, 1030 may include diffractive optical elements that impart an optical power to the first and / or second waveguides 1010, 1030 thereby eliminating the need for optics / lenses in the display systems with which the waveguide assembly 1000 is used. This would reduce the size of the display systems. The first in-coupling optical element 1012 may be configured to couple red light into the first waveguide 1010 of the waveguide assembly 1000, and the second in-coupling optical element 1032 may be configured to couple green and blue light into the second waveguide 1030 of the waveguide assembly 1000.

[0093] As explained above, including the adhesive layer 1020 in the waveguide assembly 1000 increases the robustness / ruggedness of the waveguide assembly 1000 while maintaining the optical properties / performance thereof.

[0094] Figure 11 depicts in still greater detail a waveguide assembly 1100 for use with display systems, such as display system 900 depicted in Figure 9, according to some embodiments. Similar to the waveguide assembly 1000 depicted in Figure 10, the waveguide assembly 1100 includes a first waveguide 1110, a second waveguide 1130, and an adhesive layer 1120 disposed between and in direct contact with the first and second waveguides 1110, 1130. Figure 11 depicts first and second out-coupling optical elements 1114, 1134 disposed on respective outer first and second surfaces 1111 , 1133 of first and second waveguides 1110, 1130. The first out-coupling optical element 1114 has a pitch that increases from a first longitudinal end 1115 of the first waveguide 1110 to a second longitudinal end 1117 thereof. The second out-coupling optical element 1134 has a pitch that increases from a second longitudinal end 1137 of the second waveguide1130 to a first longitudinal end 1135 thereof. These changes in pitch of the first andsecond out-coupling optical elements 1114, 1134 results in perturbations / dithering, which can be tuned to achieve desired optical effects. For instance, varying the pitch of optical elements can compensate for other optical non-uniform ities / aberrations in display systems.

[0095] The increasing pitch in the first and second out-coupling optical elements 1114, 1134 disposed on respective outer first and second surfaces 1111 , 1133 of first and second waveguides 1110, 1130 can be spread two dimensionally (i.e. , in two axis). For example, in addition to increasing pitch across the plane of Figure 11 , the increasing pitch can also come into and out of the plane of Figure 11 . The pitch change may be gradual (i.e., change over a certain length (e.g., >10um, >100um, >1 mm)) in order to maintain an acceptable modulation transfer function (“MTF”) while improving uniformity.

[0096] Figure 12 depicts in still greater detail a waveguide assembly 1200 for use with display systems, such as display system 900 depicted in Figure 9, according to some embodiments. Similar to the waveguide assembly 1000 depicted in Figure 10, the waveguide assembly 1200 includes a first waveguide 1210, a second waveguide 1230, and an adhesive layer 1220 disposed between and in direct contact with the first and second waveguides 1210, 1230. Figure 12 depicts first and second out-coupling optical elements 1214, 1234 disposed on respective outer first and second surfaces 1211 , 1233 of first and second waveguides 1210, 1230. The first waveguide 1210 has a thickness that increases from a first longitudinal end 1215 of the first waveguide 1210 to a second longitudinal end 1217 thereof. The second waveguide 1230 has a thickness that also increases from a first longitudinal end 1235 of the second waveguide 1230 to a second longitudinal end 1237 thereof. These changes in thickness of the first and secondwaveguides 1210, 1230 can be tuned to achieve desired optical effects. For instance, varying the thickness of waveguides can result in smoother image generation.

[0097] In addition to the adhesive layers 1020, 1120, 1220, the inner surfaces of one or both waveguides 1010, 1030, 1110, 1130, 1210, 1230 can be imprinted with a structural support layer. For example, Figure 13 depicts a waveguide assembly 1300 for use with display systems, such as display system 900 depicted in Figure 9, according to some embodiments. Similar to the waveguide assembly 1000 depicted in Figure 10, the waveguide assembly 1300 includes a first waveguide 1310, a second waveguide 1330, and an adhesive layer 1320 disposed between and in direct contact with the first and second waveguides 1310, 1330. Figure 13 depicts first and second in-coupling and out- coupling optical elements 1312, 1314, 1332, 1334 disposed on respective outer surfaces 1311 , 1331 of first and second waveguides 1310, 1330.

[0098] The adhesive layer 1320 of the waveguide assembly 1300 depicted in Figure 13 also includes a structural support layer 1336. The structural support layer 1336 including a plurality of structural support elements 1338 imprinted onto an inner surface 1333 of the second waveguide 1330, as shown in Figure 14. In some embodiments, the structural support layer includes a sparse array of lower refractive index (e.g., less than 1 .6) structural support elements. Such structural support layers are mostly air, thereby forming a well-defined gap and structural support layer between two waveguides. Figure 16A depicts a structural support layer including a plurality of ridges 1638-1 imprinted onto a waveguide 1630-1. Figure 16B depicts a structural support layer including a plurality of pillars 1638-2 imprinted onto a waveguide 1630-2. In addition to pillars and ridges, structural support layers may include other similar structure with a small lateral dimensionrelative to the pitch of the neighboring features (e g., out-coupling optical elements) that are imprinted onto the side opposite of the structural support elements and used for out- coupling.

[0099] The structural support elements 1338 can be formed from a color absorptive material, which can be wavelength specific or over a broadband of wavelengths (e.g., a black dye, etc.) In some embodiments, the structural support elements 1338 may be light absorptive to prevent light scattering. In some embodiments, the adhesive layer 1320 may be clear. In some embodiments, the structural support elements 1338 may substantially match the index of refractive of the adhesive 1320 to be invisible to the light propagating through the waveguide assembly 1300 by TIR and undergoing reflection / refraction therein.

[0100] Figure 14 depicts an imprinted first waveguide 1310 positioned on top of an imprinted second waveguide 1330. Figure 15 depicts the adhesive layer 1320 added to the inner surface 1333 of the second waveguide 1330 before the first waveguide 1310 is moved adjacent to the side of the adhesive layer 1320 opposite of the second waveguide 1330 to form the waveguide assembly 1300 shown in Figure 13.

[0101] While Figures 13 to 16B depict structural support elements imprinted onto the inner surface of a single waveguide, in some embodiments, structural support elements may be imprinted onto the inner surfaces of both waveguides. The structural support elements forming the structural support layer may be tuned to control the structural and optical (e.g., refractive index) characteristics of the resulting waveguide assemblies.

[0102] Figure 17 depicts a waveguide assembly 1700 for use with display systems, such as display system 900 depicted in Figure 9, according to some embodiments.Similar to the waveguide assembly 1300 depicted in Figure 13, the waveguide assembly 1700 includes a first waveguide 1710, a second waveguide 1730, an adhesive layer 1720 disposed between and in direct contact with the first and second waveguides 1710, 1730, and a structural support layer 1736 in the adhesive layer 1720. Figure 17 depicts first and second in-coupling and out-coupling optical elements 1712, 1714, 1732, 1734 disposed on respective outer surfaces 1711 , 1731 of first and second waveguides 1710, 1730.

[0103] The difference between the waveguide assembly 1700 in Figure 17 and the waveguide assembly 1300 in Figure 13 is that the adhesive layer 1720 in the waveguide assembly 1700 has a porosity gradation with a high porosity near the first waveguide 1710. The high porosity near the first waveguide 1710 results in a refractive index of less than or equal to 1.1. The high porosity / low refractive index minimizes light scattering by the adhesive layer 1720 near the first waveguide 1710. This in turn decouples light leaking from the first waveguide 1710 into the second waveguide 1730. In this embodiment, structural support layer / structural support elements 1736, 1738 may be optional. Figure 17A depicts various porosity patterns for the adhesive layer 1720 that decouples light leakage between the first and second waveguide 1710, 1730.

[0104] Figure 18 depicts a waveguide assembly 1800 for use with display systems, such as display system 900 depicted in Figure 9, according to some embodiments. Similar to the waveguide assembly 1300 depicted in Figure 13, the waveguide assembly 1800 includes a first waveguide 1810, a second waveguide 1830, an adhesive layer 1820 disposed between and in direct contact with the first and second waveguides 1810, 1830, and a structural support layer 1836 in the adhesive layer 1820. Figure 18 depicts firstand second in-coupling and out-coupling optical elements 1812, 1814, 1832, 1834 disposed on respective outer surfaces 1811 , 1831 of first and second waveguides 1810, 1830.

[0105] The difference between the waveguide assembly 1800 in Figure 18 and the waveguide assembly 1300 in Figure 13 is that the out-coupling optical element 1814 in the first waveguide 1810 is configured to out-couple blue-green light and the out-coupling optical element 1834 in the second waveguide 1830 is configured to out-couple red-green light. The optical elements can be configured to interact with light in a particular range of wavelengths by modifying the various characteristics imprinted onto the waveguides including, but not limited to, height, fill factor, shape, or any combination. Optical elements can be configured to interact with light in a particular range of wavelengths by modifying these characteristics without modifying the pitch of the optical elements. When overlapped the first and second out-coupling optical elements 1814, 1834 can have similar grating orientation with 0.5 arc minute accuracy.

[0106] Figure 19 depicts a waveguide assembly 1900 for use with display systems, such as display system 900 depicted in Figure 9, according to some embodiments. Similar to the waveguide assembly 1300 depicted in Figure 13, the waveguide assembly 1900 includes a first waveguide 1910, a second waveguide 1930, an adhesive layer 1920 disposed between and in direct contact with the first and second waveguides 1910, 1930, and a structural support layer 1936 in the adhesive layer 1920. Figure 19 depicts first and second in-coupling and out-coupling optical elements 1912, 1914, 1932, 1934 disposed on respective outer surfaces 1911 , 1931 of first and second waveguides 1910, 1930.

[0107] The difference between the waveguide assembly 1900 in Figure 19 and the waveguide assembly 1300 in Figure 13 is that the first and second waveguides 1910, 1930 are configured such that they are overlapped in a way where light can still interact with each other in K-space and maintain the same exit angles. In this embodiment, structural support layer / structural support elements 1936, 1938 may be optional.

[0108] Figure 20 depicts a waveguide assembly 2000 for use with display systems, such as display system 900 depicted in Figure 9, according to some embodiments. Similar to the waveguide assembly 1300 depicted in Figure 13, the waveguide assembly 2000 includes a first waveguide 2010, a second waveguide 2030, an adhesive layer 2020 disposed between and in direct contact with the first and second waveguides 2010, 2030, and a structural support layer 2036 in the adhesive layer 2020. Figure 20 depicts first and second in-coupling and out-coupling optical elements 2012, 2014, 2032, 2034 disposed on respective outer surfaces 2011 , 2031 of first and second waveguides 2010, 2030.

[0109] The difference between the waveguide assembly 2000 in Figure 20 and the waveguide assembly 1300 in Figure 13 is that the adhesive layer 2020 does not extend into the space between the first and second waveguides 2010, 2030 overlapping the first and second in-coupling optical elements 2012, 2032. In other embodiments, the adhesive layer 2020 does not extend into the space between the first and second waveguides 2010, 2030 overlapping other portions of the waveguide assembly 2000 (e.g., overlapping portions of the first and second out-coupling optical elements 2014, 2034). In this embodiment, structural support layer / structural support elements 2036, 2038 may be optional.

[0110] Figures 21 A to 21 D depict a waveguide assembly 1300’ for use with display systems, such as display system 900 depicted in Figure 9, according to some embodiments. Similar to the waveguide assembly 1300 depicted in Figure 13, the waveguide assembly 1300’ includes a first waveguide 1310, a second waveguide 1330, an adhesive layer 1320 disposed between and in direct contact with the first and second waveguides 1310, 1330, and a structural support layer 1336 in the adhesive layer 1320. Figure 13 depicts first and second in-coupling and out-coupling optical elements 1312, 1314, 1332, 1334 disposed on respective outer surfaces 1311 , 1331 of first and second waveguides 1310, 1330.

[0111] The difference between the waveguide assembly 1300 in Figure 13 and the waveguide assembly 1300’ in Figure 13 is that first and second waveguides 1310, 1330 include diffractive and sub-diffractive structures on one or both sides thereof. The first waveguide 1310 includes first diffractive structure 1341 and the second waveguide 1330 includes second diffractive structure 1340. The first and second diffractive structures 1341 , 1340 are embedded nanostructures in the adhesive 1320. In the embodiment depicted in Figure 21 C, includes a coating 1342, which can be on the air exposed side 1311 of the first waveguide 1310 with a thickness variation of 200 nm or lower and a refractive index of less than 1 .6.

[0112] Figure 22 depicts a waveguide 2200 for use with systems for presenting images to a user’s eye, according to some embodiments. Similar to the waveguide assembly 1100 depicted in Figure 11 , the waveguide 2200 includes first and second out-coupling optical elements 2214, 2234 disposed on respective outer first and second surfaces 2211 ,2213 of waveguide 2200. The first out-coupling optical element 2214 has a pitch thatincreases from a first longitudinal end 2215 of the waveguide 2200 to a second longitudinal end 2217 thereof. The second out-coupling optical element 2234 has a pitch that increases from the second longitudinal end 2217 of the waveguide 2200 to the first longitudinal end 2215 thereof. These changes in pitch of the first and second out-coupling optical elements 2214, 2234 results in perturbations / dithering, which can be tuned to achieve desired optical effects. For instance, varying the pitch of optical elements can compensate for other optical non-uniform ities / aberrations in display systems.System Architecture Overview

[0113] Figure 23 is a block diagram of an illustrative computing system 2300 suitable for implementing an embodiment of the present disclosure. Computer system 2300 includes a bus 2306 or other communication mechanism for communicating information, which interconnects subsystems and devices, such as processor 2307, system memory 2308 (e.g., RAM), static storage device 2309 (e.g., ROM), disk drive 2310 (e.g., magnetic or optical), communication interface 2314 (e.g., modem or Ethernet card), display 2311 (e.g., CRT or LCD), input device 2312 (e.g., keyboard), and cursor control.

[0114] According to one embodiment of the disclosure, computer system 2300 performs specific operations by processor 2307 executing one or more sequences of one or more instructions contained in system memory 2308. Such instructions may be read into system memory 2308 from another computer readable / usable medium, such as static storage device 2309 or disk drive 2310. In alternative embodiments, hard-wired circuitry may be used in place of or in combination with software instructions to implement the disclosure. Thus, embodiments of the disclosure are not limited to any specific combination of hardware circuitry and / or software. In one embodiment, the term “logic”shall mean any combination of software or hardware that is used to implement all or part of the disclosure.

[0115] The term “computer readable medium” or “computer usable medium” as used herein refers to any medium that participates in providing instructions to processor 2307 for execution. Such a medium may take many forms, including but not limited to, nonvolatile media and volatile media. Non-volatile media includes, for example, optical or magnetic disks, such as disk drive 2310. Volatile media includes dynamic memory, such as system memory 2308.

[0116] Common forms of computer readable media includes, for example, floppy disk, flexible disk, hard disk, magnetic tape, any other magnetic medium, CD-ROM, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, RAM, PROM, EPROM, FLASH-EPROM (e.g., NAND flash, NOR flash), any other memory chip or cartridge, or any other medium from which a computer can read.

[0117] In an embodiment of the disclosure, execution of the sequences of instructions to practice the disclosure is performed by a single computer system 2300. According to other embodiments of the disclosure, two or more computer systems 2300 coupled by communication link 2315 (e.g., LAN, PTSN, or wireless network) may perform the sequence of instructions required to practice the disclosure in coordination with one another.

[0118] Computer system 2300 may transmit and receive messages, data, and instructions, including program, i.e., application code, through communication link 2315 and communication interface 2314. Received program code may be executed by processor 2307 as it is received, and / or stored in disk drive 2310, or other non-volatilestorage for later execution. Database 2332 in storage medium 2331 may be used to store data accessible by system 2300 via data interface 2333.

[0119] While the waveguide assemblies are describe herein as implemented in various display systems, the waveguide assemblies described herein may be implemented in various other display systems. For instance, various display system and method embodiments in which the waveguide assemblies described herein may be implemented are depicted and described in U.S. Utility Patent Application Serial No. 17 / 705,202, the contents of which have been previously incorporated by reference herein.

[0120] Certain aspects, advantages and features of the disclosure have been described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment of the disclosure. Thus, the disclosure may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.

[0121] Embodiments have been described in connection with the accompanying drawings. However, it should be understood that the figures are not drawn to scale. Distances, angles, etc. are merely illustrative and do not necessarily bear an exact relationship to actual dimensions and layout of the devices illustrated. In addition, the foregoing embodiments have been described at a level of detail to allow one of ordinary skill in the art to make and use the devices, systems, methods, and the like described herein. A wide variety of variation is possible. Components, elements, and / or steps may be altered, added, removed, or rearranged.

[0122] The devices and methods described herein can advantageously be at least partially implemented using, for example, computer software, hardware, firmware, or any combination of software, hardware, and firmware. Software modules can include computer executable code, stored in a computer’s memory, for performing the functions described herein. In some embodiments, computer-executable code is executed by one or more general purpose computers. However, a skilled artisan will appreciate, in light of this disclosure, that any module that can be implemented using software to be executed on a general purpose computer can also be implemented using a different combination of hardware, software, or firmware. For example, such a module can be implemented completely in hardware using a combination of integrated circuits. Alternatively or additionally, such a module can be implemented completely or partially using specialized computers designed to perform the particular functions described herein rather than by general purpose computers. In addition, where methods are described that are, or could be, at least in part carried out by computer software, it should be understood that such methods can be provided on non-transitory computer-readable media that, when read by a computer or other processing device, cause it to carry out the method.

[0123] While certain embodiments have been explicitly described, other embodiments will become apparent to those of ordinary skill in the art based on this disclosure.

[0124] The various processors and other electronic components described herein are suitable for use with any optical system for projecting light. The various processors and other electronic components described herein are also suitable for use with any audio system for receiving voice commands.

[0125] Various exemplary embodiments of the disclosure are described herein. Reference is made to these examples in a non-limiting sense. They are provided to illustrate more broadly applicable aspects of the disclosure. Various changes may be made to the disclosure described and equivalents may be substituted without departing from the true spirit and scope of the disclosure. In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process, process act(s) or step(s) to the objective(s), spirit or scope of the present disclosure. Further, as will be appreciated by those with skill in the art, each of the individual variations described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present disclosure. All such modifications are intended to be within the scope of claims associated with this disclosure.

[0126] The disclosure includes methods that may be performed using the subject devices. The methods may include the act of providing such a suitable device. Such provision may be performed by the end user. In other words, the “providing” act merely requires the end user obtain, access, approach, position, set-up, activate, power-up or otherwise act to provide the requisite device in the subject method. Methods recited herein may be carried out in any order of the recited events which is logically possible, as well as in the recited order of events.

[0127] Exemplary aspects of the disclosure, together with details regarding material selection and manufacture have been set forth above. As for other details of the present disclosure, these may be appreciated in connection with the above-referenced patents and publications as well as generally known or appreciated by those with skill in the art.The same may hold true with respect to method-based aspects of the disclosure in terms of additional acts as commonly or logically employed.

[0128] In addition, though the disclosure has been described in reference to several examples optionally incorporating various features, the disclosure is not to be limited to that which is described or indicated as contemplated with respect to each variation of the disclosure. Various changes may be made to the disclosure described and equivalents (whether recited herein or not included for the sake of some brevity) may be substituted without departing from the true spirit and scope of the disclosure. In addition, where a range of values is provided, it is understood that every intervening value, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the disclosure.

[0129] Also, it is contemplated that any optional feature of the variations described may be set forth and claimed independently, or in combination with any one or more of the features described herein. Reference to a singular item, includes the possibility that there are plural of the same items present. More specifically, as used herein and in claims associated hereto, the singular forms “a,” “an,” “said,” and “the” include plural referents unless the specifically stated otherwise. In other words, use of the articles allow for “at least one” of the subject item in the description above as well as claims associated with this disclosure. It is further noted that such claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as “solely,” “only” and the like in connection with the recitation of claim elements, or use of a “negative” limitation.

[0130] Without the use of such exclusive terminology, the term “comprising” in claims associated with this disclosure shall allow for the inclusion of any additional element- irrespective of whether a given number of elements are enumerated in such claims, or the addition of a feature could be regarded as transforming the nature of an element set forth in such claims. Except as specifically defined herein, all technical and scientific terms used herein are to be given as broad a commonly understood meaning as possible while maintaining claim validity.

[0131] The breadth of the present disclosure is not to be limited to the examples provided and / or the subject specification, but rather only by the scope of claim language associated with this disclosure.

[0132] In the foregoing specification, the disclosure has been described with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the disclosure. For example, the above-described process flows are described with reference to a particular ordering of process actions. However, the ordering of many of the described process actions may be changed without affecting the scope or operation of the disclosure. The specification and drawings are, accordingly, to be regarded in an illustrative rather than restrictive sense.

Claims

ClaimsWhat is claimed is:1 . An extended reality display system, comprising: a light source to emit light; a waveguide assembly to receive and direct the light; and a spatial light modulator (SLM) configured to receive the light, wherein the waveguide assembly comprises a first waveguide, a second waveguide, and an adhesive layer disposed between and in direct contact with the first and second waveguides.

2. The system of claim 1 , wherein the first waveguide comprises: a first in-coupling optical element disposed on a second surface of the first waveguide; and a first out-coupling optical element disposed on a first surface of the first waveguide, wherein the second surface is opposite of the first surface, and wherein the adhesive layer is in direct contact with the second surface of the first waveguide.

3. The system of claim 2, wherein the second waveguide comprises:a second in-coupling optical element and a second out-coupling optical element disposed on a second surface of the second waveguide; and a first surface disposed opposite of the second surface, wherein the adhesive layer is in direct contact with the first surface of the second waveguide.

4. The system of claim 3, wherein the first out-coupling optical element comprises a first plurality of diffractive optical elements having a first variable pitch increasing from a first end of the waveguide assembly to a second end of the waveguide assembly, and wherein the first end of the waveguide assembly is opposite of the second end of the waveguide assembly.

5. The system of claim 4, wherein the second out-coupling optical element comprises a second plurality of diffractive optical elements having a second variable pitch increasing from the second end of the waveguide assembly to the first end of the waveguide assembly.

6. The system of claim 3, wherein the first waveguide has a first variable thickness increasing from a first end of the waveguide assembly to a second end of the waveguide assembly, and wherein the first end of the waveguide assembly is opposite of the second end of the waveguide assembly.

7. The system of claim 6, wherein the second waveguide has a second variable thickness increasing from the second end of the waveguide assembly to the first end of the waveguide assembly.

8. The system of claim 7, wherein the first out-coupling optical element comprises a first plurality of diffractive optical elements having a first constant pitch, and wherein the second out-coupling optical element comprises a second plurality of diffractive optical elements having a second constant pitch.

9. The system of claim 1 , wherein the first waveguide is configured to direct light of a first color.

10. The system of claim 1 , wherein the second waveguide is configured to direct light of a second color and a third color.11 . The system of claim 1 , wherein the adhesive layer comprises a structural support layer including a plurality of structural support elements imprinted onto an inner surface of the second waveguide.

12. An extended reality display system, comprising: a light source to emit light; a waveguide to receive and direct the light; anda spatial light modulator (SLM) configured to receive the light, wherein the waveguide comprises a first plurality of diffractive optical elements disposed on a first surface of the waveguide, and a second plurality of diffractive optical elements disposed on a second surface of the waveguide, wherein the first surface of the waveguide is opposite of the second surface of the waveguide, wherein the first plurality of diffractive optical elements has a first variable pitch increasing from a first end of the waveguide to a second end of the waveguide, wherein the second plurality of diffractive optical elements has a second variable pitch increasing from the second end of the waveguide to the first end of the waveguide, and wherein the first end of the waveguide is opposite of the second end of the waveguide.

Images