Cover architecture in curved eyepiece stacks for mixed reality applications

Abstract

An eyepiece and a method of manufacturing the eyepiece are disclosed. In some embodiments, the eyepiece comprises a curved cover layer and a waveguide layer for propagating light. In some embodiments, the curved cover layer comprises an anti-reflective feature. In the present disclosure, an eyepiece is provided that comprises a curved cover layer, the curved cover layer comprising an anti-reflective feature, a waveguide layer configured to propagate light generated by a projector, an opening configured to optically couple the projector to the waveguide layer, and a second cover layer.

Description

Technical Field

[0001] Cross-Reference to Related Applications This application claims the benefit of priority of U.S. Provisional Patent Application No. 63 / 176,102, filed on April 16, 2021, the content of which is hereby incorporated by reference in its entirety into the present specification.

[0002] Field The present disclosure relates generally to eyepiece stacks, and in particular to cover architectures in curved eyepiece stacks for mixed reality (MR) applications.

Background Art

[0003] Background It may be desirable to use a curved cover layer in eyepiece stacks for MR applications. For example, the curved cover layer may be adapted to fit the curved waveguide of the eyepiece stack to improve optical performance. As another example, the curved cover layer may improve the structural properties of the eyepiece. However, reflections generated by the curved cover layer may produce ghost images (e.g., shifted reflections) for the viewer, and using high-temperature (e.g., 100°C) deposition and / or vacuum deposition to produce anti-reflection features for reducing ghost images may be costly. Accordingly, a less expensive method of producing anti-reflection features for curved cover layers to more efficiently obtain the benefits of curved cover layers may be desirable.

Summary of the Invention

Means for Solving the Problems

[0004] Summary Examples of the present disclosure describe an eyepiece and a method of manufacturing the eyepiece. In some embodiments, the eyepiece comprises a curved cover layer for propagating light and a waveguide layer. In some embodiments, the curved cover layer comprises anti-reflection features.

[0005] In some embodiments, the waveguide layer is curved.

[0006] In some embodiments, the eyepiece further comprises a second cover layer.

[0007] In some embodiments, the second cover layer is curved.

[0008] In some embodiments, the curved cover layer has a second anti-reflective feature.

[0009] In some embodiments, anti-reflective features are produced by casting, using moth-eye film, spin coating, dipping coating, or spray coating.

[0010] In some embodiments, the cover layer is curved toward the waveguide layer.

[0011] In some embodiments, the cover layer is curved away from the waveguide layer.

[0012] In some embodiments, the light propagating within the waveguide layer is generated from a projector.

[0013] In some embodiments, the length of the curved cover layer is shorter than the length of the waveguide layer.

[0014] In some embodiments, the curved cover layer is provided with holes.

[0015] In some embodiments, a method for manufacturing an eyepiece includes providing a waveguide layer for propagating light and providing a curved cover layer.

[0016] In some embodiments, the waveguide layer is curved.

[0017] In some embodiments, the method further includes providing a second cover layer.

[0018] In some embodiments, the second cover layer is curved.

[0019] In some embodiments, the method further includes forming anti-reflection features on the curved cover layer.

[0020] In some embodiments, the anti-reflection features are fabricated by casting, using a moth-eye film, spin coating, dip coating, or spray coating.

[0021] In some embodiments, the cover layer is curved toward the waveguide layer.

[0022] In some embodiments, the cover layer is curved away from the waveguide layer.

[0023] In some embodiments, the method further includes optically coupling a projector to the waveguide layer, where the projector generates light that propagates within the waveguide layer.

[0024] In some embodiments, the length of the curved cover layer is shorter than the length of the waveguide layer.

[0025] In some embodiments, the method further includes forming holes in the curved cover layer.

[0026] In some embodiments, the wearable head device comprises a first eyepiece of any of the above eyepieces and a second eyepiece of any of the above eyepieces. The present invention provides, for example, the following items: (Item 1) It is an eyepiece, A curved cover layer, wherein the curved cover layer has anti-reflective properties, A waveguide layer configured to propagate light generated by a projector, An opening configured to optically couple the projector to the waveguide layer, The second cover layer and An eyepiece equipped with [a specific feature / feature]. (Item 2) The waveguide layer is curved, as described in item 1. (Item 3) The aforementioned second cover layer is curved, as described in item 1 of the eyepiece. (Item 4) The curved cover layer has a second anti-reflective feature, as described in item 1. (Item 5) The eyepiece described in item 1, wherein the anti-reflective feature is produced by casting using a moth-eye film, spin coating, dip coating, and spray coating. (Item 6) The eyepiece described in item 1, wherein the cover layer is curved in the direction toward the waveguide layer. (Item 7) The eyepiece described in item 1, wherein the cover layer is curved in a direction away from the waveguide layer. (Item 8) The eyepiece described in item 1, wherein the length of the curved cover layer is shorter than the length of the waveguide layer. (Item 9) The curved cover layer comprises the opening described in item 1, the eyepiece as described in item 1. (Item 10) A method for manufacturing an eyepiece, wherein the method is A waveguide layer configured to propagate light received from a projector is provided, By providing a curved cover layer with anti-reflective properties, By providing a second cover layer, The waveguide layer is provided with an opening configured to optically couple to the projector. Methods that include... (Item 11) The waveguide layer is curved, as described in item 10. (Item 12) The method according to item 10, wherein the second cover layer is curved. (Item 13) The method according to item 10, wherein the anti-reflective feature is produced by casting using a moth-eye film, spin coating, dip coating, and spray coating. (Item 14) The method according to item 10, wherein the cover layer is curved in the direction toward the waveguide layer. (Item 15) The method according to item 10, wherein the cover layer is curved away from the waveguide layer. (Item 16) The method according to item 10, wherein the length of the curved cover layer is shorter than the length of the waveguide layer. (Item 17) The method according to item 10, wherein providing the opening includes forming a hole in the curved cover layer. (Item 18) It is a wearable head device, The first eyepiece, A projector optically coupled to the first eyepiece and Equipped with, The aforementioned first eyepiece is, A curved cover layer, wherein the curved cover layer has anti-reflective properties, A waveguide layer configured to propagate light generated by a projector, An opening configured to optically couple the projector to the waveguide layer, The second cover layer and A wearable head device equipped with [features / equipment]. [Brief explanation of the drawing]

[0027] [Figure 1A] Figures 1A to 1C show exemplary environments relating to one or more embodiments of the present disclosure. [Figure 1B] Figures 1A to 1C show exemplary environments relating to one or more embodiments of the present disclosure. [Figure 1C] Figures 1A to 1C show exemplary environments relating to one or more embodiments of the present disclosure.

[0028] [Figure 2A] Figures 2A to 2D show exemplary components of a mixed reality system according to an embodiment of the present disclosure. [Figure 2B] Figures 2A to 2D show exemplary components of a mixed reality system according to an embodiment of the present disclosure. [Figure 2C] Figures 2A to 2D show exemplary components of a mixed reality system according to an embodiment of the present disclosure. [Figure 2D] Figures 2A to 2D show exemplary components of a mixed reality system according to an embodiment of the present disclosure.

[0029] [Figure 3A] Figure 3A shows an exemplary mixed reality handheld controller according to an embodiment of the present disclosure.

[0030] [Figure 3B] Figure 3B shows an exemplary auxiliary unit according to an embodiment of the present disclosure.

[0031] [Figure 4] Figure 4 shows an exemplary functional block diagram of an exemplary mixed reality system according to an embodiment of the present disclosure.

[0032] [Figure 5A] Figures 5A and 5B show exemplary waveguide layers according to embodiments of the present disclosure. [Figure 5B] Figures 5A and 5B show exemplary waveguide layers according to embodiments of the present disclosure.

[0033] [Figure 6A] Figures 6A to 6C show exemplary eyepiece stacks according to embodiments of the present disclosure. [Figure 6B] Figures 6A to 6C show exemplary eyepiece stacks according to embodiments of the present disclosure. [Figure 6C] Figures 6A to 6C show exemplary eyepiece stacks according to embodiments of the present disclosure.

[0034] [Figure 7] Figure 7 shows an exemplary cover layer according to an embodiment of the present disclosure.

[0035] [Figure 8] Figure 8 shows an exemplary cover layer according to an embodiment of the present disclosure.

[0036] [Figure 9] Figure 9 shows an exemplary cover layer according to an embodiment of the present disclosure.

[0037] [Figure 10-1] Figures 10A to 10E show exemplary eyepiece characteristics according to embodiments of the present disclosure. [Figure 10-2] Figures 10A to 10E show exemplary eyepiece characteristics according to embodiments of the present disclosure.

[0038] [Figure 11] Figure 11 shows an exemplary eyepiece stack according to an embodiment of the present disclosure.

[0039] [Figure 12] Figure 12 shows an exemplary method for manufacturing an eyepiece according to an embodiment of the present disclosure. [Modes for carrying out the invention]

[0040] Detailed explanation The following examples refer to the accompanying drawings illustrating specific examples that form part of this specification and can be implemented. It should be understood that other examples may be used and structural modifications may be made without departing from the scope of the disclosed examples.

[0041] Like all people, users of a mixed reality system are present in the real environment, that is, in all three-dimensional parts and contents of the "real world" that are perceptible to the user. For example, the user perceives the real environment using their normal human senses (sight, sound, touch, taste, smell) and interacts with the real environment by moving their body within it. A position in the real environment can be described as coordinates in coordinate space. For example, coordinates can include latitude, longitude, and altitude relative to sea level; distance in three orthogonal dimensions from a reference point; or other appropriate values. Similarly, vectors can describe quantities that have direction and magnitude in coordinate space.

[0042] A computing device can maintain a representation of a virtual environment in, for example, the memory associated with the device. As used herein, a virtual environment is a computational representation of a three-dimensional space. A virtual environment can include representations of any object, action, signal, parameter, coordinate, vector, or other properties associated with that space. In some examples, the circuitry of a computing device (e.g., a processor) can maintain and update the state of a virtual environment. That is, the processor can determine the state of the virtual environment at a second time t1 based on data associated with the virtual environment and / or inputs provided by the user at a first time t0. For example, if an object in the virtual environment is located at a first coordinate at time t0 and has certain programmed physical parameters (e.g., mass, coefficient of friction), the input received from the user instructs that a force should be applied to the object in a direction vector. The processor can apply the laws of kinematics to determine the object's position at time t1 using basic mechanics. The processor can determine the state of the virtual environment at time t1 using any appropriate information known about the virtual environment and / or any appropriate inputs. When maintaining and updating the state of a virtual environment, the processor may run any appropriate software, including: software related to the creation and deletion of virtual objects in the virtual environment; software for defining the behavior of virtual objects or characters in the virtual environment (e.g., scripts); software for defining the behavior of signals in the virtual environment (e.g., audio signals); software for creating and updating parameters associated with the virtual environment; software for generating audio signals in the virtual environment; software for handling input and output; software for implementing network operations; software for applying asset data (e.g., animation data for moving virtual objects over time); or many other possibilities.

[0043] Output devices such as displays or speakers can present any or all aspects of a virtual environment to the user. For example, a virtual environment may include virtual objects that can be presented to the user (this may include representations of inanimate objects; people; animals; lights, etc.). A processor can determine a view of the virtual environment (e.g., corresponding to a “camera” with origin coordinates, view axes, and a frustum) and render a viewable scene of the virtual environment corresponding to that view on the display. Any suitable rendering technique may be used for this purpose. In some examples, a viewable scene may include several virtual objects in the virtual environment and exclude certain other virtual objects. Similarly, a virtual environment may include audio aspects that can be presented to the user as one or more audio signals. For example, virtual objects in the virtual environment may generate sounds resulting from the object’s position coordinates (e.g., a virtual character may speak or produce sound effects). Alternatively, a virtual environment may be associated with musical cues or ambient sounds that may or may not be associated with a specific location. The processor can handle audio signals corresponding to "listener" coordinates, such as the synthesis of sounds within a virtual environment, determine a mixed and processed audio signal to simulate the audio signal heard by the listener at listener coordinates, and present the audio signal to the user through one or more speakers.

[0044] Because virtual environments exist as computational structures, users cannot directly perceive them using their normal senses. Instead, users can perceive virtual environments indirectly, such as through displays, speakers, or haptic output devices. Similarly, while users cannot directly touch, manipulate, or interact with virtual environments, they can provide input data via input devices or sensors to a processor that can use the device or sensor data to update the virtual environment. For example, a camera sensor can provide optical data indicating that the user is attempting to move an object within the virtual environment, and the processor can use that data to cause the object to respond accordingly within the virtual environment.

[0045] A mixed reality system can present a user with a mixed reality environment (MRE) that combines aspects of the real and virtual environments, for example, using a transparent display and / or one or more speakers (which may be incorporated, for example, into a wearable head device). In some embodiments, one or more speakers may be located outside the wearable head device. As used herein, an MRE is a simultaneous representation of the real environment and its corresponding virtual environment. In some examples, the corresponding real and virtual environments share a single coordinate space. In some examples, the real coordinate space and the corresponding virtual coordinate space are related to each other by a transformation matrix (or other suitable representation). Thus, a single coordinate (in some examples, together with the transformation matrix) can define a first location in the real environment and a second corresponding location in the virtual environment, and vice versa.

[0046] In MRE, virtual objects (e.g., in a virtual environment associated with the MRE) can correspond to real-world objects (e.g., in a real-world environment associated with the MRE). For example, if the real-world environment of the MRE includes a real-world ramp post (real-world object) at its position coordinates, the virtual environment of the MRE may include a virtual ramp post (virtual object) at its corresponding position coordinates. As used herein, a real-world object, combined with its corresponding virtual object, constitutes a "mixed-reality object." A virtual object does not need to perfectly match or align with its corresponding real-world object. In some examples, a virtual object can be a simplified version of its corresponding real-world object. For example, if the real-world environment includes a real-world ramp post, the corresponding virtual object may include a cylinder with approximately the same height and radius as the real-world ramp post (reflecting that the ramp post can have a nearly cylindrical shape). Simplifying virtual objects in this way can improve computational efficiency and simplify calculations performed on such virtual objects. Furthermore, in some examples of MRE, not all real-world objects in the real-world environment are necessarily associated with corresponding virtual objects. Similarly, in some MRE examples, not all virtual objects within the virtual environment are necessarily associated with corresponding real-world objects. That is, some virtual objects may exist only within the MRE's virtual environment without any real-world counterparts.

[0047] In some examples, virtual objects may have properties that sometimes differ significantly from those of their corresponding real-world objects. For instance, a real-world environment within an MRE might contain a green, two-armed cactus (a thorny, inanimate object), while a corresponding virtual object within the MRE might possess the characteristics of a green, two-armed virtual character with human facial features and an expressionless face. In this example, the virtual object resembles its corresponding real-world object in certain properties (color, number of arms), but differs in other properties (facial features, personality). In this way, virtual objects can represent real-world objects in creative, abstract, exaggerated, or imaginative ways, or otherwise give behavior (e.g., human personality) to inanimate real-world objects. In some examples, virtual objects may be purely imaginative creations with no real-world counterparts (e.g., a virtual monster in a virtual environment that, in some cases, occupies a position corresponding to an empty space in the real-world environment).

[0048] In some cases, virtual objects possess characteristics similar to their corresponding real-world objects. For example, a virtual character may be presented as a living person in a virtual or mixed reality environment to provide the user with an immersive mixed reality experience. With a virtual character possessing lifelike features, the user may feel as if they are interacting with a real person. In such cases, it is desirable that the virtual character's movements, such as muscle movements and gaze, appear natural. For example, the movements of a virtual character should be similar to those of its corresponding real-world object (for instance, a virtual human should walk and move their arms like a real human). As another example, the gestures and positioning of a virtual human should appear natural, and the virtual human should be able to perform initial interactions with the user (for example, the virtual human can lead a collaborative experience with the user). Here, we will elaborate further on the presentation of virtual characters with lifelike features.

[0049] Compared to virtual reality (VR) systems, which present a virtual environment to the user while obscuring the real environment, mixed reality systems presenting MRE offer the advantage that the real environment remains perceptible while the virtual environment is being presented. Therefore, users of mixed reality systems can experience and interact with the corresponding virtual environment using visual and auditory cues associated with the real environment. For example, as described herein, users of VR systems may struggle to perceive or interact with virtual objects displayed in the virtual environment because they cannot directly perceive or interact with the virtual environment; however, users of MR systems may find it more intuitive and natural to interact with virtual objects by seeing, hearing, and touching the corresponding real objects within their own real environment. This level of interactivity can enhance immersion, connection, and engagement with the virtual environment. Similarly, by presenting the real and virtual environments simultaneously, mixed reality systems can reduce the negative psychological (e.g., cognitive dissonance) and physical (e.g., motion sickness) associated with VR systems. Mixed reality systems further offer many possibilities for applications that can enhance or modify the experience of the real world.

[0050] Figure 1A shows an exemplary reality environment 100 in which a user 110 uses a mixed reality system 112. The mixed reality system 112 may comprise a display (e.g., a transmissive display) and one or more speakers, as well as one or more sensors (e.g., a camera), as described herein, for example. The illustrated reality environment 100 includes a rectangular room 104A in which the user 110 is standing, and reality objects 122A (a lamp), 124A (a table), 126A (a sofa), and 128A (a painting). Room 104A may be spatially described by position coordinates (e.g., coordinate system 108). The location of the reality environment 100 may be described with respect to the origin of the position coordinates (e.g., point 106). As shown in Figure 1A, an environment / world coordinate system 108 (including x-axis 108X, y-axis 108Y, and z-axis 108Z) having its origin 106 (world coordinates) can define the coordinate space of the reality environment 100. In some embodiments, the origin 106 of the environment / world coordinate system 108 may correspond to the location where the mixed reality system 112 is powered on. In some embodiments, the origin 106 of the environment / world coordinate system 108 may be reset during operation. In some examples, the user 110 may be considered a real object in the real environment 100. Similarly, parts of the user 110's body (e.g., hands, feet) may be considered real objects in the real environment 100. In some examples, a user / listener / head coordinate system 114 (including x-axis 114X, y-axis 114Y, and z-axis 114Z) with point 115 (e.g., user / listener / head coordinate) as its origin can define a coordinate space for the user / listener / head on which the mixed reality system 112 is positioned. The origin 115 of the user / listener / head coordinate system 114 may be defined for one or more components of the mixed reality system 112. For example, the origin 115 of the user / listener / head coordinate system 114 may be defined relative to the display of the mixed reality system 112, such as during the initial calibration of the mixed reality system 112. Matrices (which may include translation matrices and quaternion matrices or other rotation matrices), or other suitable representations, can characterize the transformation between the user / listener / head coordinate system 114 space and the environment / world coordinate system 108 space.In some embodiments, the left ear coordinates 116 and the right ear coordinates 117 may be defined relative to the origin 115 of the user / listener / head coordinate system 114. Matrices (which may include translation matrices and quaternion matrices or other rotation matrices), or other suitable representations, can characterize the transformation between the left ear coordinates 116 and the right ear coordinates 117 and the user / listener / head coordinate system 114 space. The user / listener / head coordinate system 114 can simplify the representation of the user's head, or the position of a head-mounted device relative to, for example, the environment / world coordinate system 108. The transformation between the user coordinate system 114 and the environment coordinate system 108 can be determined and updated in real time using simultaneous localization and mapping (SLAM), visual odometry, or other techniques.

[0051] Figure 1B shows an exemplary virtual environment 130 corresponding to the real environment 100. The illustrated virtual environment 130 includes a virtual rectangular room 104B corresponding to the real rectangular room 104A, and virtual objects 122B corresponding to the real object 122A; virtual object 124B corresponding to the real object 124A; and virtual object 126B corresponding to the real object 126A. The metadata associated with virtual objects 122B, 124B, and 126B may include information derived from the corresponding real objects 122A, 124A, and 126A. The virtual environment 130 further includes a virtual character 132 that does not correspond to any real object in the real environment 100. The real object 128A in the real environment 100 does not correspond to any virtual object in the virtual environment 130. A persistent coordinate system 133 (including the x-axis 133X, y-axis 133Y, and z-axis 133Z) with point 134 as its origin can define the coordinate space of virtual content. The origin 134 of the persistent coordinate system 133 may be defined with respect to / relative to one or more real objects, such as real object 126A. Matrices (which may include translation matrices and quaternion matrices or other rotation matrices), or other suitable representations, can characterize transformations between the persistent coordinate system 133 space and the environment / world coordinate system 108 space. In some embodiments, each of the virtual objects 122B, 124B, 126B, and 132 may have its own persistent coordinate point with respect to the origin 134 of the persistent coordinate system 133. In some embodiments, there may be multiple persistent coordinate systems, and each of the virtual objects 122B, 124B, 126B, and 132 may have its own persistent coordinate point with respect to one or more persistent coordinate systems.

[0052] Persistent coordinate data can be coordinate data that persists relative to the physical environment. Persistent coordinate data may be used by an MR system (e.g., MR systems 112, 200) to position persistent virtual content, and the persistent virtual content does not have to be tied to the movement of the display on which the virtual object is displayed. For example, a two-dimensional screen may display a virtual object relative to a position on the screen. As the two-dimensional screen moves, the virtual content may move with the screen. In some embodiments, persistent virtual content may be displayed in the corner of a room. The MR user may look at the corner, look at the virtual content, look out from the corner (the virtual content may no longer be visible because, due to the movement of the user's head, it may have moved from within the user's field of view to outside the user's field of view), or look behind and look at the virtual content in the corner (similar to how a real object may behave).

[0053] In some embodiments, persistent coordinate data (e.g., a persistent coordinate system and / or persistent coordinate frame) may include an origin and three axes. For example, a persistent coordinate system may be assigned by the MR system to the center of a room. In some embodiments, the user may move around in the room, leave the room, and re-enter the room, and the persistent coordinate system may remain at the center of the room (e.g., persisting relative to the physical environment). In some embodiments, virtual objects may be displayed using a transformation to persistent coordinate data that enables the display of persistent virtual content. In some embodiments, the MR system may use simultaneous localization and mapping to generate persistent coordinate data (e.g., the MR system may assign persistent coordinate systems to points in space). In some embodiments, the MR system may map the environment by generating persistent coordinate data at regular intervals (e.g., the MR system may assign persistent coordinate systems within a grid, where each persistent coordinate system may be at least 5 feet from another persistent coordinate system).

[0054] In some embodiments, persistent coordinate data may be generated by the MR system and transmitted to a remote server. In some embodiments, the remote server may be configured to receive persistent coordinate data. In some embodiments, the remote server may be configured to synchronize persistent coordinate data from multiple observation instances. For example, multiple MR systems may map the same room with persistent coordinate data and transmit that data to the remote server. In some embodiments, the remote server may use this observation data to generate standard persistent coordinate data that can be obtained based on one or more observations. In some embodiments, the standard persistent coordinate data may be more accurate and / or reliable than a single observation of persistent coordinate data. In some embodiments, the standard persistent coordinate data may be transmitted to one or more MR systems. For example, an MR system may use image recognition and / or location data to recognize that it is located in a room with corresponding standard persistent coordinate data (e.g., from the fact that another MR system has previously mapped the room). In some embodiments, an MR system may receive standard persistent coordinate data corresponding to its location from the remote server.

[0055] In relation to Figures 1A and 1B, the environment / world coordinate system 108 defines a shared coordinate space for both the real environment 100 and the virtual environment 130. In the illustrated example, the coordinate space has its origin at point 106. Furthermore, the coordinate space is defined by the same three orthogonal axes (108X, 108Y, 108Z). Thus, a first location in the real environment 100 and a second corresponding location in the virtual environment 130 can be described with respect to the same coordinate space. This simplifies the identification and representation of corresponding locations in the real and virtual environments, as the same coordinates can be used to identify both locations. However, in some examples, the corresponding real and virtual environments do not need to use a shared coordinate space. For example, in some examples (not shown), matrices (which may include translational matrices and quaternion matrices or other rotation matrices), or other suitable representations, can characterize transformations between the real environment coordinate space and the virtual environment coordinate space.

[0056] Figure 1C shows an exemplary MRE 150 that simultaneously presents aspects of the real environment 100 and the virtual environment 130 to the user 110 via a mixed reality system 112. In the illustrated example, the MRE 150 simultaneously presents to the user 110 real objects 122A, 124A, 126A, and 128A from the real environment 100 (e.g., via the transparent portion of the display of the mixed reality system 112) and virtual objects 122B, 124B, 126B, and 132 from the virtual environment 130 (e.g., via the active display portion of the display of the mixed reality system 112). As described herein, the origin 106 serves as the origin of the coordinate space corresponding to the MRE 150, and the coordinate system 108 defines the x, y, and z axes of the coordinate space.

[0057] In the illustrated example, the mixed reality object includes corresponding pairs of real and virtual objects (e.g., 122A / 122B, 124A / 124B, 126A / 126B) that occupy corresponding positions in coordinate space 108. In some examples, both the real and virtual objects may be visible to the user 110 simultaneously. This may be desirable, for example, when the virtual object presents information designed to extend the view of the corresponding real object (such as in a museum application where the virtual object presents a missing piece of an old, damaged sculpture). In some examples, the virtual object (122B, 124B, and / or 126B) may be displayed in a way that obscures the corresponding real object (122A, 124A, and / or 126A) (e.g., via active pixelated occlusion using a pixelated occlusion shutter). This may be desirable, for example, when the virtual object acts as a visual replacement for the corresponding real object (such as in an interactive storytelling application where an inanimate real object becomes a “living” character).

[0058] In some examples, real-world objects (e.g., 122A, 124A, 126A) may be associated with virtual content or helper data that does not necessarily constitute a virtual object. Virtual content or helper data can facilitate the processing or handling of virtual objects in a mixed reality environment. For example, such virtual content may include a two-dimensional representation of the corresponding real-world object; a custom asset type associated with the corresponding real-world object; or statistical data associated with the corresponding real-world object. This information can enable or facilitate calculations involving real-world objects without incurring unnecessary computational overhead.

[0059] In some examples, the presentations described herein may also incorporate audio modes. For example, in MRE150, a virtual character 132 may be associated with one or more audio signals, such as footsteps generated when the character walks around MRE150. As described herein, the processor of the mixed reality system 112 may compute an audio signal corresponding to the mixture and processed synthesis of all such sounds within MRE150 and present the audio signal to the user 110 via one or more speakers included in the mixed reality system 112 and / or one or more external speakers.

[0060] An exemplary mixed reality system 112 may include a wearable head device (e.g., a wearable augmented reality or mixed reality head device) comprising: displays (which may comprise left and right transmissive displays, which may be near-eye displays, and associated components for coupling light from the displays to the user's eyes); left and right speakers (e.g., positioned adjacent to the user's left and right ears, respectively); an inertial measuring unit (IMU) (e.g., mounted on the temple arms of the head device); an orthogonal coil electromagnetic receiver (e.g., mounted on the left temple piece); left and right cameras (e.g., depth (time-of-flight) cameras) oriented away from the user; and left and right eye cameras oriented towards the user (e.g., for detecting the user's eye movements). However, the mixed reality system 112 may incorporate any suitable display technology and any suitable sensors (e.g., optical, infrared, acoustic, LIDAR, EOG, GPS, magnetic). Furthermore, the mixed reality system 112 may incorporate networking capabilities (e.g., Wi-Fi capabilities, mobile network (e.g., 4G, 5G) capabilities) for communicating with other devices and systems, including a neural network (e.g., in the cloud) for data processing and training data related to the presentation of the MRE 150 and other elements within the mixed reality system (e.g., virtual character 132). The mixed reality system 112 may further include a battery (which may be mounted in an auxiliary unit such as a belt pack designed to be worn around the user's waist), a processor, and memory. The wearable head device of the mixed reality system 112 may include tracking components such as an IMU or other suitable sensors configured to output a set of coordinates of the wearable head device relative to the user's environment. In some examples, the tracking components may provide input to a processor that performs simultaneous localization and mapping (SLAM) and / or visual odometry algorithms. In some examples, the mixed reality system 112 may also include a handheld controller 300 and / or auxiliary unit 320, which may be a wearable belt pack as described herein.

[0061] In some embodiments, an animation rig is used to present a virtual character 132 to the MRE 150. Although the animation rig is described in relation to the virtual character 132, it is understood that the animation rig may be associated with other characters in the MRE 150 (e.g., human characters, animal characters, abstract characters). The movement of the animation rig will be described in more detail herein.

[0062] Figures 2A to 2D show components of an exemplary mixed reality system 200 (which may correspond to mixed reality system 112) that may be used to present an MRE (which may correspond to MRE150) or other virtual environment to a user. Figure 2A shows a perspective view of a wearable head device 2102 included in the exemplary mixed reality system 200. Figure 2B shows a plan view of the wearable head device 2102 mounted on a user's head 2202. Figure 2C shows a front view of the wearable head device 2102. Figure 2D shows an end view of an exemplary eyepiece 2110 of the wearable head device 2102. As shown in Figures 2A to 2C, the exemplary wearable head device 2102 includes an exemplary left eyepiece (e.g., a left transparent waveguide set eyepiece) 2108 and an exemplary right eyepiece (e.g., a right transparent waveguide set eyepiece) 2110. The eyepieces 2108 and 2110 may include a curved layer as described herein. Eyepieces 2108 and 2110 may be the eyepieces disclosed with respect to Figures 6 to 12. Each eyepiece 2108 and 2110 may include a transmission element from which the real environment can be viewed, as well as a display element for presenting a display that overlaps with the real environment (e.g., via imagewise modulated light). In some examples, such a display element may include a surface diffractive optical element for controlling the flow of imagewise modulated light. For example, the left eyepiece 2108 may include a left internally coupled grating set 2112, a left orthogonal pupillary dilation (OPE) grating set 2120, and a left exit (output) pupillary dilation (EPE) grating set 2122. Similarly, the right eyepiece 2110 may include a right internally coupled grating set 2118, a right OPE grating set 2114, and a right EPE grating set 2116. Imagewise modulated light can be transmitted to the user's eye via internally coupled gratings 2112 and 2118, OPE 2114 and 2120, and EPE 2116 and 2122. Each internally coupled grating set 2112, 2118 can be configured to deflect light toward its corresponding OPE grating set 2120, 2114.Each OPE grating set 2120, 2114 can be designed to gradually deflect light downward toward its associated EPE 2122, 2116, thereby extending the formed exit pupil horizontally. Each EPE 2122, 2116 can be configured to gradually redirect at least a portion of the light received from its corresponding OPE grating set 2120, 2114 toward the user's eyebox position (not shown) defined behind the eyepieces 2108, 2110, thereby extending the formed exit pupil vertically toward the eyebox. Alternatively, instead of the internal coupling grating sets 2112 and 2118, OPE grating sets 2114 and 2120, and EPE grating sets 2116 and 2122, the eyepieces 2108 and 2110 may include other arrangements of gratings and / or refractive and reflective mechanisms to control the coupling of imagewise-modulated light to the user's eye.

[0063] In some examples, the wearable head device 2102 may include a left temple arm 2130 and a right temple arm 2132, the left temple arm 2130 including a left speaker 2134, and the right temple arm 2132 including a right speaker 2136. The orthogonal coil electromagnetic receiver 2138 may be located within the left temple piece or in another suitable location within the wearable head unit 2102. The inertial measurement unit (IMU) 2140 may be located within the right temple arm 2132 or in another suitable location within the wearable head device 2102. The wearable head device 2102 may also include a left depth (e.g., time-of-flight) camera 2142 and a right depth camera 2144. The depth cameras 2142 and 2144 may be appropriately oriented in different directions to cover a wider field of view together.

[0064] In the examples shown in Figures 2A to 2D, the left source 2124 of imagewise modulated light can be optically coupled to the left eyepiece 2108 via the left internal coupling grating set 2112, and the right source 2126 of imagewise modulated light can be optically coupled to the right eyepiece 2110 via the right internal coupling grating set 2118. The imagewise modulated light sources 2124 and 2126 can include, for example, fiber optic scanners; projectors including electronic optical modulators such as digital light processing (DLP) chips or liquid crystal on silicon (LCoS) modulators; or light-emitting displays such as micro light-emitting diodes (μLEDs) or micro organic light-emitting diode (μOLED) panels coupled to the internal coupling grating sets 2112 and 2118 using one or more lenses on each side. The input coupling grating sets 2112 and 2118 can deflect the light from the imagewise modulated light sources 2124 and 2126 to an angle exceeding the critical angle of total internal reflection (TIR) ​​of the eyepieces 2108 and 2110. The OPE grid sets 2114 and 2120 gradually deflect the light propagating by TIR downwards toward the EPE grid sets 2116 and 2122. The EPE grid sets 2116 and 2122 gradually fuse the light toward the user's face, including the pupil of the user's eye.

[0065] In some examples, as shown in Figure 2D, each of the left eyepiece 2108 and the right eyepiece 2110 includes multiple waveguides 2402. For example, each eyepiece 2108, 2110 may include multiple individual waveguides, each dedicated to its respective color channel (e.g., red, blue, and green). In some examples, each eyepiece 2108, 2110 may include multiple sets of such waveguides, each set configured to impart a different wavefront curvature to the emitted light. The wavefront curvature may be convex to the user's eye, for example, to present a virtual object positioned at a distance in front of the user (e.g., only a distance corresponding to the reciprocal of the wavefront curvature). In some examples, the EPE grid sets 2116, 2122 may include curved grid grooves that achieve convex wavefront curvature by changing the Poynting vector of the emitted light crossing each EPE.

[0066] In some examples, stereoscopically adjusted left and right eye images can be presented to the user through imagewise optical modulators 2124, 2126 and eyepieces 2108, 2110 to create the perception that the displayed content is three-dimensional. The perceived presence of the three-dimensional virtual object can be enhanced by selecting waveguides (and thus corresponding to wavefront curvature) so that the virtual object is displayed at a distance close to the distance indicated by the stereoscopic left and right images. This technique can also reduce motion sickness experienced by some users, which may be caused by the difference between the depth perception cue provided by the stereoscopic left and right eye images and the autonomic nervous system regulation of the human eye (e.g., focus depending on object distance).

[0067] Figure 2D shows a top-down end view of the right eyepiece 2110 of an exemplary wearable head device 2102. As shown in Figure 2D, the waveguides 2402 may include a first subset 2404 of three waveguides and a second subset 2406 of three waveguides. The two subsets of waveguides 2404, 2406 can be distinguished by different EPE gratings featuring different grating line curvatures to impart different wavefront curvatures to the emitted light. Within each subset 2404, 2406 of waveguides, each waveguide can be used to couple different spectral channels (e.g., one of the red, green, and blue spectral channels) to the user's right eye 2206. Although not shown in Figure 2D, the structure of the left eyepiece 2108 may be mirror-image inverted with respect to the structure of the right eyepiece 2110.

[0068] Figure 3A shows an exemplary handheld controller component 300 of the mixed reality system 200. In some examples, the handheld controller 300 includes a grip portion 346 and one or more buttons 350 arranged along the top surface 348. In some examples, the buttons 350 may be configured to be used as optical tracking targets for tracking, for example, six-degree-of-freedom (6DOF) motion of the handheld controller 300, together with a camera or other optical sensor (which may be mounted on the head unit of the mixed reality system 200 (e.g., a wearable head device 2102)). In some examples, the handheld controller 300 includes a tracking component (e.g., an IMU or other suitable sensor) for detecting position or orientation, such as position or orientation relative to the wearable head device 2102. In some examples, such a tracking component may be located within the handle of the handheld controller 300 and / or mechanically coupled to the handheld controller. The handheld controller 300 can be configured to provide one or more output signals corresponding to one or more of the following: the state of a button being pressed; or the position, orientation, and / or movement of the handheld controller 300 (e.g., via the IMU). Such output signals can be used as inputs to the processor of the mixed reality system 200. Such inputs may correspond to the position, orientation, and / or movement of the handheld controller (and, by extension, the position, orientation, and / or movement of the user's hand holding the controller). Such inputs may also correspond to the user pressing button 350.

[0069] Figure 3B shows an exemplary auxiliary unit 320 of the mixed reality system 200. The auxiliary unit 320 may include a battery to supply energy to operate the system 200 and may include a processor to run programs to operate the system 200. As shown, the exemplary auxiliary unit 320 includes a clip 2128 for attaching the auxiliary unit 320 to a user's belt, for example. Other form factors, including form factors that do not involve attaching the unit to a user's belt, may be suitable for the auxiliary unit 320 and will become apparent. In some examples, the auxiliary unit 320 is coupled to a wearable head device 2102 via a multi-conduit cable that may include, for example, electric wires and optical fibers. Wireless connectivity between the auxiliary unit 320 and the wearable head device 2102 may also be used.

[0070] In some examples, the mixed reality system 200 may include one or more microphones for detecting sound and providing corresponding signals to the mixed reality system. In some examples, the microphones may be attached to or integrated with the wearable head device 2102 and may be configured to detect the user's voice. In some examples, the microphones may be attached to or integrated with the handheld controller 300 and / or auxiliary unit 320. Such microphones may be configured to detect ambient sounds, surrounding noise, the voice of the user or a third party, or other sounds.

[0071] Figure 4 shows an exemplary functional block diagram that may correspond to an exemplary mixed reality system, such as mixed reality system 200 described herein (which may correspond to mixed reality system 112 relating to Figure 1). Elements of the wearable system 400 may be used to implement the methods, operations, and features described herein. As shown in Figure 4, an exemplary handheld controller 400B (which may correspond to handheld controller 300 ("Totem")) includes a totem-to-wearable head device 6-degree-of-freedom (6DOF) totem subsystem 404A, and an exemplary wearable head device 400A (which may correspond to wearable head device 2102) includes a totem-to-wearable head device 6DOF subsystem 404B. In this example, the 6DOF totem subsystem 404A and the 6DOF subsystem 404B work together to determine six coordinates of the handheld controller 400B relative to the wearable head device 400A (e.g., three translational offsets and three rotations along axes). The six degrees of freedom can be expressed relative to the coordinate system of the wearable head device 400A. The three translational offsets can be expressed as X, Y, and Z offsets in such a coordinate system, as a translational matrix, or as any other representation. The rotational degrees of freedom can be expressed as a sequence of yaw, pitch, and roll rotations, as a rotation matrix, as a quaternion, or as any other representation. In some examples, the wearable head device 400A; one or more depth cameras 444 (and / or one or more non-depth cameras) included in the wearable head device 400A; and / or one or more optical targets (e.g., button 350 on the handheld controller 400B as described herein, or a dedicated optical target included in the handheld controller 400B) can be used for 6DOF tracking. In some examples, the handheld controller 400B may include a camera as described herein, and the wearable head device 400A may include an optical target for optical tracking in conjunction with the camera.In some examples, the wearable head device 400A and the handheld controller 400B each include a set of three orthogonally oriented solenoids used to wirelessly transmit and receive three identifiable signals. The 6DOF of the wearable head device 400A relative to the handheld controller 400B can be determined by measuring the relative magnitudes of the three identifiable signals received in each of the coils used for receiving. Furthermore, the 6DOF totem subsystem 404A may include an inertial measurement unit (IMU) that is useful for providing improved accuracy and / or more timely information regarding the rapid movement of the handheld controller 400B.

[0072] In some embodiments, the wearable system 400 may include a microphone array 407 that includes one or more microphones positioned on a headgear device 400A. In some embodiments, the microphone array 407 may include four microphones. Two microphones may be positioned on the front of the headgear 400A, and two microphones may be positioned on the back of the headgear 400A (e.g., one on the left rear and one on the right rear). In some embodiments, the signals received by the microphone array 407 may be transmitted to a DSP 408. The DSP 408 may be configured to perform signal processing on the signals received from the microphone array 407. For example, the DSP 408 may be configured to perform noise reduction, acoustic echo rejection, and / or beamforming on the signals received from the microphone array 407. The DSP 408 may be configured to transmit the signals to a processor 416.

[0073] In some cases, for example, it may be necessary to transform the coordinates from local coordinate space (e.g., a coordinate space fixed relative to the wearable head device 400A) to inertial coordinate space (e.g., a coordinate space fixed relative to the real environment) in order to compensate for the movement of the wearable head device 400A (e.g., of the MR system 112) relative to coordinate system 108. For example, such a transformation may be necessary so that the display of the wearable head device 400A presents the virtual object in a position and orientation that is expected relative to the real environment (e.g., the same position in the lower right corner of the display) and orientation, rather than a fixed position and orientation on the display, in order to maintain the illusion that a virtual object exists in the real environment (e.g., a virtual person sitting in a real chair and facing forward regardless of the position and orientation of the wearable head device) (and so that, for example, the wearable head device 400A does not appear to be unnaturally positioned in the real environment when it moves and rotates). In some examples, compensatory transformations between coordinate spaces can be determined by processing images from a depth camera 444 using SLAM and / or visual odometry procedures to determine the transformation of the wearable head device 400A to coordinate system 108. In the example shown in Figure 4, the depth camera 444 can be coupled to a SLAM / visual odometry block 406 and provide images to the block 406. An implementation of the SLAM / visual odometry block 406 may include a processor configured to process these images and determine the position and orientation of the user's head, which can be used to identify transformations between the head coordinate space and another coordinate space (e.g., inertial coordinate space). Similarly, in some examples, additional information about the user's head pose and position is obtained from an IMU 409. Information from the IMU 409 can be integrated with information from the SLAM / visual odometry block 406 to provide improved accuracy and / or more timely information regarding rapid adjustment of the user's head pose and position.

[0074] In some examples, the depth camera 444 can supply 3D images to a hand gesture tracker 411, which may be implemented in the processor of a wearable head device 400A. The hand gesture tracker 411 can identify the user's hand gestures, for example, by matching the 3D images received from the depth camera 444 with stored patterns representing hand gestures. Other suitable techniques for identifying the user's hand gestures will become apparent.

[0075] In some examples, one or more processors 416 may be configured to receive data from the wearable head device's 6DOF headgear subsystem 404B, IMU 409, SLAM / visual odometry block 406, depth camera 444, and / or hand gesture tracker 411. The processor 416 may also send and receive control signals from the 6DOF totem system 404A. The processor 416 may be wirelessly coupled to the 6DOF totem system 404A, as in an example where the handheld controller 400B is not connected. The processor 416 may further communicate with additional components such as an audiovisual content memory 418, a graphical processing unit (GPU) 420, and / or a digital signal processor (DSP) voice spatializer 422. The DSP voice spatializer 422 may be coupled to a head-related transfer function (HRTF) memory 425. The GPU 420 may include a left channel output coupled to a left source 424 of imagewise modulated light (for displaying content on the left eyepiece 428) and a right channel output coupled to a right source 426 of imagewise modulated light (for displaying content on the right eyepiece 430). Eyepieces 428 and 430 may include a curved layer, as described herein. Eyepieces 428 and 430 may be the eyepieces disclosed with reference to Figures 6 to 12. The GPU 420 may output stereoscopic image data to the imagewise modulated light sources 424 and 426, as described herein, for example, with reference to Figures 2A to 2D. In some examples, the GPU 420 may be used to render virtual elements in the MRE presented on the display of the wearable system 400. The DSP audio spatializer 422 may output audio to the left speaker 412 and / or the right speaker 414. The DSP audio spatializer 422 can receive an input from the processor 419 indicating a direction vector from the user to a virtual sound source (which can be moved by the user, for example, via the handheld controller 320).Based on the direction vector, the DSP voice spatializer 422 can determine the corresponding HRTF (for example, by accessing or interpolating multiple HRTFs). The DSP voice spatializer 422 can then apply the determined HRTF to an audio signal, such as an audio signal corresponding to a virtual sound generated by a virtual object. This can enhance the realism and presence of the virtual sound by incorporating the user's relative position and orientation to the virtual sound in the mixed reality environment, that is, by presenting a virtual sound that matches the user's expectation of how that virtual sound would sound if it were a real sound in a real environment.

[0076] In some examples, as shown in Figure 4, one or more of the processor 416, GPU 420, DSP voice spatializer 422, HRTF memory 425, and audiovisual content memory 418 may be included in an auxiliary unit 400C (which may correspond to the auxiliary unit 320 described herein). The auxiliary unit 400C may include a battery 427 for powering its components and / or for powering the wearable head device 400A or the handheld controller 400B. Including such components in an auxiliary unit that can be worn on the user's waist can limit the size and weight of the wearable head device 400A, and thus reduce fatigue in the user's head and neck.

[0077] Figure 4 shows elements corresponding to various components of an exemplary wearable system 400, although various other suitable arrangements of these components will become apparent to those skilled in the art. For example, the shown headgear device 400A may include a processor and / or battery (not shown). The included processor and / or battery may operate together with the processor and / or battery of the auxiliary unit 400C, or in place of the processor and / or battery of the auxiliary unit 400C. In general, as another example, elements or functions described with respect to Figure 4 as relating to the auxiliary unit 400C may instead be associated with the headgear device 400A or the handheld controller 400B. Furthermore, some wearable systems may completely omit the handheld controller 400B or the auxiliary unit 400C. Such variations and modifications should be understood to fall within the scope of the disclosed examples.

[0078] Figures 5A and 5B show exemplary waveguide layers according to embodiments of the present disclosure. Figure 5A is a simplified cross-sectional view of the waveguide layer of an eyepiece and the light projected from the waveguide layer, in which the waveguide layer is characterized by a predetermined curvature, according to some embodiments. The waveguide layer 504 may be the waveguide layer described with respect to Figures 6A and 6C. An incident light beam 502 from a light source such as a projector (e.g., the projector described with respect to Figures 6A and 6C, or the imagewise modulated light source 2124, 2126, 424, or 426) can enter the waveguide layer 504 through the incident surface 506 (e.g., by diffraction from an internal coupling element (not shown)) and exit toward the user's eye 510 through the exit surface 508. As shown in Figure 5A, a surface profile characterizes the waveguide layer 504. In some embodiments, the surface profile forms a curve that can be defined by the radius of curvature of a spherical curvature. In some embodiments, the surface profile is aspherical but can be approximated by a spherical shape. Due to the structure of the waveguide layer 504, the incident surface 506 can be substantially parallel to the exit surface 508 along the entire length of the waveguide layer 504.

[0079] As light propagates through the waveguide layer 504 by total internal reflection (TIR), the exiting light is diffracted out of the waveguide layer 504, as indicated by the exiting ray. For low levels of curvature, the incident surface 506 and the exit surface 508 are substantially parallel to each other at positions across the waveguide layer. Therefore, as light propagates through the waveguide layer by TIR, the parallelism of the waveguide surfaces preserves the reflection angle in TIR, and consequently, the angle between the exiting ray and the exit surface is preserved across the waveguide layer. Because the surface normal changes slightly across the exit surface of the curved waveguide layer, the exiting ray also changes slightly, producing the divergence shown in Figure 5A.

[0080] The divergence of the emitted light rays resulting from the curvature of the emission surface 508 can have the effect of rendering the incident light beam 502 so that the light appears to originate from a point source located at a specific distance behind the waveguide layer 504. Thus, the surface profile or curvature of the waveguide layer 504 generates a divergence of light toward the user's or observer's eye 510, effectively rendering the light as originating from a depth plane located behind the waveguide layer relative to the eye.

[0081] The distance from which the incident light beam appears to originate from the waveguide layer can be associated with the radius of curvature of the waveguide layer 504. Waveguides with a higher radius of curvature can render light sources as originating at a greater distance from the waveguide layer than waveguides with a lower radius of curvature. For example, as shown in Figure 5A, the waveguide layer 504 can have a radius of curvature of 0.5 m, which can be achieved by the arch shape of the waveguide layer 504 of 0.4 mm across an EPE with a lateral dimension (e.g., length or width) of 40 mm. Given this exemplary curvature of the waveguide layer 504, the incident light beam 502 appears to originate at a distance of 0.5 m from the waveguide layer 504. As another example, another waveguide layer can be operated to have a radius of curvature of 0.2 m, rendering to the user a light source that appears to originate at a distance of 0.2 m from the waveguide layer. Therefore, by utilizing a curvature across a waveguide layer with a length / depth of several tens of millimeters that is compatible with the waveguide layer material, i.e., a 1-millimeter bow-shaped portion, a depth surface function can be implemented for a two-dimensional expanding waveguide, also known as a two-dimensional waveguide. The curvature used according to embodiments of the present invention can be used in a variety of commercially available products, including sunglasses and vehicle windshields, which can have a bow shape of several millimeters (e.g., 1-5 mm). Therefore, the small amount of curvature used in various embodiments of the present invention does not degrade the optical performance of the eyepiece. For example, an eyepiece with a radius of curvature of 0.5 m can introduce less than 0.1 min⁻¹ of blur in the central field of view and less than 2 min⁻¹ of blur across the entire field of view.

[0082] Figure 5A shows only a one-dimensional cross-sectional view of the waveguide layer 504, which is an element of the eyepiece. However, it will be understood that the surface profile imposed on the waveguide layer can also be imposed in a direction perpendicular to the plane of the figure, resulting in a two-dimensional curvature of the waveguide layer. Thus, embodiments of the present invention provide depth plane functionality to the structure of the eyepiece, in particular to the waveguide layer of the eyepiece. As described herein, the depth plane functionality can be bimodal or continuous depending on the particular implementation.

[0083] Figure 5B is a simplified cross-sectional view of the waveguide layer of an eyepiece and the light passing through the waveguide layer, according to several embodiments, where the waveguide layer is characterized by a predetermined curvature. As described with respect to Figure 5A, the light projected from the waveguide layer 504 can make the light source visible to the user's eye in three-dimensional space. Real-world light 512, or light not projected through the waveguide layer 504 for virtual reality (VR), augmented reality (AR), or mixed reality (MR) purposes, can pass through the incident surface 506 and exit surface 508 of the waveguide layer 504 towards the user's eye 510. Waveguides with small variations in thickness (e.g., less than 1.0 μm) have negligible optical power and can allow real-world light 512 to pass through the curved surface of the waveguide layer 504 with little or no disturbance. In some embodiments, correction of real-world light is not required, and off-axis degradation of real-world light caused by the surface profile of the waveguide layer 504 is reduced or absent. Therefore, imposing a surface profile or curvature on the waveguide layer allows for the projection of virtual content from a position away from the eyepiece while maintaining the integrity of real-world light, thereby enabling both the user to see real-world light and, at the same time, to render virtual content in three-dimensional space for the user in real time.

[0084] In some embodiments, the radius of curvature of the waveguide layer, which may be a polymer waveguide layer, can be dynamically varied between a first distance (e.g., 0.1 m) and infinity, thereby allowing the depth plane of the eyepiece (i.e., the distance at which the projected light source appears to be rendered) to be dynamically varied between the first distance and infinity. Thus, embodiments of the present invention enable variation of the depth plane between a first distance (e.g., 0.1 m) and infinity, including depth planes commonly used in augmented or mixed reality applications. The surface profile of the waveguide layer, for example, a flexible polymer waveguide layer, can be tuned using various methodologies and mechanisms, as will be described in more detail herein.

[0085] In some embodiments, a dynamic eyepiece is provided, where the depth plane of the eyepiece can be varied to display virtual content on different depth planes, for example, by providing a temporal variation as a function of time. Thus, subsequent frames of virtual content can be displayed as originating from different depth planes. However, static implementations are also included within the scope of the invention. In these static implementations, a fixed predetermined surface profile or curvature characterizes the waveguide layer of the eyepiece, thereby presenting virtual content on a fixed depth plane. In contrast to some systems that utilize external lenses, diffractive lenses, or other optical elements, embodiments utilizing static implementations can implement depth planes through the curvature of the waveguide layer, reducing system complexity and improving optical quality. Furthermore, some embodiments can implement a set of eyepieces, each eyepiece including a stack of curved waveguide layers to provide two static depth planes. For example, a first stack of three curved waveguide layers can utilize a 0.2 mm arch shape across the width / length of the waveguide stack to implement a three-color scene in a depth plane located at 1 m, and a second stack of three curved waveguide layers can utilize a 0.4 mm arch shape across the width / length of the waveguide stack to implement a second three-color scene in a depth plane located at 0.5 m. Other suitable dimensions are within the scope of the present invention. Furthermore, binocular and monocular systems are conceived.

[0086] In some embodiments, the disclosed eyepiece waveguide is as described in U.S. Patent Application Publication No. 2021 / 0011305, the entire disclosure of which is incorporated herein by reference. The disclosed waveguide can improve the presentation of images (e.g., mixed reality (MR) content) to the user by improving optical properties in a cost-effective manner.

[0087] For MR applications, it may be desirable to use a curved cover layer in the eyepiece stack. For example, as mentioned above, a curved cover layer can be adapted to a curved waveguide to improve optical performance. As another example, a curved cover layer can improve the structural properties of the eyepiece (e.g., improved geometric stiffness, improved response to thermomechanical loads).

[0088] Figures 6A to 6C show exemplary eyepiece stacks according to embodiments of the present disclosure. Figures 6A to 6C may show cross-sectional views of the eyepiece stack. In the figures, the top represents the world side (e.g., the side of the eyepiece more distal to the observer in a wearable head device equipped with the eyepiece), and the bottom represents the observer side (e.g., the side of the eyepiece more proximal to the observer in a wearable head device equipped with the eyepiece). A first cover layer may be associated with the world side, and a second cover layer may be associated with the observer side.

[0089] While the disclosed eyepiece is shown as including the described elements, it is understood that different combinations of elements, additional elements, or fewer elements may be included in the eyepiece without departing from the scope of this disclosure. For example, the eyepiece may include additional or fewer waveguide layers. As another example, one or both cover layers may be curved. As yet another example, one or both cover layers may be curved toward or away from the waveguide layer. As yet another example, one or both cover layers may be cut (as described in more detail below). As yet another example, one or both cover layers may have holes (as described in more detail below). As yet another example, the eyepiece may include combinations of cover layer and / or waveguide layer features as described with respect to Figures 6A–6C.

[0090] Figure 6A shows an exemplary eyepiece stack 600. In some embodiments, as shown, the eyepiece stack 600 includes a first cover layer 602, a first waveguide layer 604, a second waveguide layer 606, a third waveguide layer 608, and a second cover layer 610. As shown, the first cover layer 602 may be a curved cover layer, and the second cover layer 610 may be a non-curved (e.g., flat) cover layer. The first cover layer 602 may be curved away from the waveguide layers, as shown. For example, over a length of 4 cm, the difference between the peaks and troughs of the curved cover layer may be about 1 mm. In some embodiments, the radius of curvature of the curved cover layer is 0.1 m to 1 m. In some embodiments, the radius of curvature of the curved cover layer is greater than 1 m (e.g., up to infinity) to cover the depth plane required for MR applications. The radius of curvature can be measured by projecting light through the curved layer and measuring the focal length of the projection (e.g., focal length = radius of curvature / 2). Similarly, depth planes for specific MR applications can be satisfied by adjusting the curvature of the eyepiece stack to the corresponding focal length. In some embodiments, the curvature of the first cover layer reduces the gap between the first cover layer and the adjacent curved waveguide layer, reducing the probability of the two layers coming into contact (e.g., interfering with light propagating through the waveguide layer) and / or reducing the probability of eyepiece structural instability (e.g., wobbling) compared to a non-curved first cover layer.

[0091] In some embodiments, the first cover layer 602 and / or the second cover layer 610 are provided with anti-reflective features. The anti-reflective features may be geometric features or materials of the cover layer, and the geometric features or materials are configured to reduce the reflection of incident radiation having a particular wavelength compared to a cover layer without geometric features. The geometric features or materials may be formed as described with respect to Figures 7 to 9. The anti-reflective features may be anti-reflective features described herein (for example, described with respect to Figures 7 to 12). As an exemplary advantage, the disclosed anti-reflective features may allow for more efficient implementation of the curved cover layer to adapt to curved waveguides and / or to increase the structural strength of the eyepiece (e.g., improved geometric stiffness, improved response to thermomechanical loads). For example, the disclosed anti-reflective features can reduce ghost images (e.g., ghost ratios from 230:1 (e.g., for polymer cover layers without anti-reflective features (e.g., refractive index = 1.75)) to 13.5:1 compared to curved cover layers with weaker anti-reflective properties), can be fabricated without using high-temperature deposition or vacuum deposition, and can reduce the manufacturing cost and / or complexity of the eyepiece (e.g., by reducing expensive manufacturing steps).

[0092] In some embodiments, waveguide layers 604, 606, and 608 are curved waveguide layers. The first waveguide layer 604 may be a waveguide for blue light. The second waveguide layer 606 may be a waveguide for green light. The third waveguide layer 608 may be a waveguide for red light. It is understood that the waveguide layers may be arranged in ways different from those described. For example, an eyepiece may contain more or fewer waveguide layers. As another example, the first, second, and / or third waveguide layers may be waveguides for appropriate color wavelengths other than those described above.

[0093] In some embodiments, the light propagating within the waveguide layer is provided by projector 612. Projector 612 may be a projector for presenting MR content to the user of a wearable head device, as described above. For example, projector 612 is a spatial light modulator. Projector 612 may be an imagewise modulated light source 2124, 2126, 424, or 426.

[0094] Figure 6B shows an exemplary eyepiece stack 620. In some embodiments, as shown, the eyepiece stack 620 includes a first cover layer 622, a first waveguide layer 624, a second waveguide layer 626, a third waveguide layer 628, and a second cover layer 630. As shown, the first cover layer 622 and the second cover layer 630 may be curved cover layers. As shown, the first cover layer 622 may be curved away from the waveguide layer, and the second cover layer 630 may be curved toward the waveguide layer. For example, over a length of 4 cm, the difference between the peaks and troughs of the curved cover layer may be 1 mm. In some embodiments, the curvature of the first and second cover layers allows for improved geometric stiffness of the eyepiece stack compared to an eyepiece stack with uncurved (e.g., flat) first and second cover layers.

[0095] In some embodiments, the first cover layer 622 and / or the second cover layer 630 are provided with anti-reflective features. The anti-reflective features may be those described herein (for example, those described with respect to Figures 7 to 12). As an exemplary advantage, the disclosed anti-reflective features may allow for more efficient implementation of the curved cover layer to adapt to curved waveguides and / or to increase the structural strength of the eyepiece (e.g., improved geometric stiffness, improved response to thermomechanical loads). For example, the disclosed anti-reflective features may reduce ghost images (e.g., compared to a curved cover layer with weaker anti-reflective properties), may be fabricated without using high-temperature or vacuum deposition, and may reduce the manufacturing cost and / or complexity of the eyepiece (e.g., by reducing expensive manufacturing steps).

[0096] In some embodiments, waveguide layers 624, 626, and 628 are non-curved (e.g., flat) waveguide layers. The first waveguide layer 624 may be a waveguide for blue light. The second waveguide layer 626 may be a waveguide for green light. The third waveguide layer 628 may be a waveguide for red light. It is understood that the waveguide layers may be arranged differently than described. For example, an eyepiece may contain more or fewer waveguide layers. As another example, the first, second, and / or third waveguide layers may be waveguides for appropriate color wavelengths other than those described above.

[0097] In some embodiments, the light propagating within the waveguide layer is provided by projector 632. Projector 632 may be a projector for presenting MR content to the user of a wearable head device, as described above. For example, projector 632 may include a spatial light modulator. Projector 632 may be an imagewise modulated light source 2124, 2126, 424, or 426.

[0098] Figure 6C shows an exemplary eyepiece stack 640. In some embodiments, as shown, the eyepiece stack 640 includes a first cover layer 642, a first waveguide layer 644, a second waveguide layer 646, a third waveguide layer 648, and a second cover layer 650. As shown, the first cover layer 642 and the second cover layer 650 may be curved cover layers. The first cover layer 642 and the second cover layer 650 may be curved away from the waveguide layers, as shown. For example, over a length of 4 cm, the difference between the peaks and troughs of the curved cover layer may be 1 mm. In some embodiments, the curvature of the first and second cover layers allows for improved geometric stiffness of the eyepiece stack compared to an eyepiece stack with uncurved (e.g., flat) first and second cover layers.

[0099] In some embodiments, the first cover layer 642 and / or the second cover layer 650 are provided with anti-reflective features. The anti-reflective features may be those described herein (for example, with respect to Figures 7 to 12). As an exemplary advantage, the disclosed anti-reflective features may allow for more efficient implementation of the curved cover layer to adapt to curved waveguides and / or to increase the structural strength of the eyepiece (e.g., improved geometric stiffness, improved response to thermomechanical loads). For example, the disclosed anti-reflective features may reduce ghost images (e.g., compared to a curved cover layer with weaker anti-reflective properties), may be fabricated without using high-temperature or vacuum deposition, and may reduce the manufacturing cost and / or complexity of the eyepiece (e.g., by reducing expensive manufacturing steps).

[0100] In some embodiments, waveguide layers 644, 646, and 648 are non-curved (e.g., flat) waveguide layers. The first waveguide layer 644 may be a waveguide for blue light. The second waveguide layer 646 may be a waveguide for green light. The third waveguide layer 648 may be a waveguide for red light. It is understood that the waveguide layers may be arranged differently than described. For example, an eyepiece may contain more or fewer waveguide layers. As another example, the first, second, and / or third waveguide layers may be waveguides for appropriate color wavelengths other than those described above.

[0101] In some embodiments, the light propagating within the waveguide layer is provided by projector 652. Projector 652 may be a projector for presenting MR content to the user of a wearable head device, as described above. For example, projector 652 may include a spatial light modulator. Projector 652 may be an imagewise modulated light source 2124, 2126, 424, or 426.

[0102] In some embodiments, the length of the cover layer (e.g., the distance between the two ends of the cover layer) is shorter than the length of the waveguide layer (e.g., the distance between the two ends of the waveguide layer). That is, the curved cover layer is cut out from the waveguide layer. The cutout can be made by cutting or casting. For example, as shown, the length of the curved cover layer 642 (e.g., the distance between the two ends of the curved cover layer) is shorter than the length of the waveguide layers 644, 646, or 648 (e.g., the distance between the two ends of the waveguide layer). In some embodiments, the cover layer has holes. For example, as shown, the second cover layer 650 has holes 654. In some embodiments, the cover layer has two or more holes.

[0103] In some embodiments, the cut-out cover layer and / or holes may allow the projector to be positioned closer to the waveguide layer, reducing the required size and / or power requirements of the projector and shortening the optical path length. For example, by cutting out and / or forming holes in the cover layer, more space is freed up near the waveguide layer, allowing at least a portion of the projector to be positioned near the waveguide layer (e.g., a portion of the projector is positioned in the cut-out portion or hole). By allowing the projector to be positioned closer to the waveguide layer, the required size, cost, weight, and / or power consumption of the projector (e.g., MR systems, wearable head devices) may be reduced.

[0104] Reflections generated by a curved cover layer can produce ghost images (e.g., shifted reflections) for the observer, and using high-temperature deposition and / or vacuum deposition to create anti-reflective features to reduce ghost images can be costly. Therefore, to more efficiently obtain the advantages of a curved cover layer, a less expensive method for generating anti-reflective features for the curved cover layer may be desirable.

[0105] Figure 7 shows exemplary cover layers (e.g., a non-curved cover layer 700A, a curved cover layer 700B) according to embodiments of the present disclosure. In some embodiments, the cover layer is the cover layer described with respect to Figures 6A to 6C. In some embodiments, the cover layer comprises a polymer (e.g., a polymer different from the polymer in the waveguide layer, or the same polymer as the polymer in the waveguide layer). In some embodiments, the cover layer comprises an anti-reflective feature 702. The anti-reflective feature 702 may be fabricated on one or both sides of the cover layer. For brevity, some advantages of the anti-reflective feature described with respect to other figures will not be repeated here.

[0106] In some embodiments, the anti-reflective feature 702 is manufactured by casting. For example, the anti-reflective feature 702 may be manufactured using a casting process for an anti-reflective grid (e.g., using a mold). For example, a process similar to the process for casting a surface relief grid into a high refractive index polymer for waveguides may be used to manufacture the grid structure. The casting process manufactures a pattern (e.g., a grid) on the surface of the cover layer, and the pattern is configured to reduce light reflection from the corresponding surface.

[0107] For example, a binary anti-reflective grating with a height of 85 nm and a period of 50% at that height (e.g., a periodic structure resembling a square wave in cross-section) can yield surface reflectance values ​​of 2.9% for blue wavelengths, 1.7% for green wavelengths, and 2.5% for red wavelengths. The height of the binary anti-reflective grating can be one-quarter of the incident light wavelength. As another example, a binary anti-reflective grating with a height of 100 nm and a period of 35% at that height can yield surface reflectance values ​​of 2.7% for blue wavelengths, 0.7% for green wavelengths, and 1.4% for red wavelengths. As yet another example, customizing the height of the binary grating for each wavelength (80 nm for blue, 100 nm for green, and 120 nm for red) and 35% of the period at each height can yield reflectances of 0.7% for blue, green, and red wavelengths. In some embodiments, the refractive index of the cast bulk polymer (e.g., a cover layer material without anti-reflective properties) is in the range of 1.4 to 1.9, and the height of the binary lattice and the ratio of the period at that height can be adjusted to produce the desired anti-reflective properties.

[0108] By creating anti-reflective features by casting, more expensive and / or complex anti-reflective feature formation processes such as high-temperature deposition and / or vacuum deposition may be eliminated, reducing the manufacturing cost and / or complexity of the eyepiece (e.g., by eliminating the need for additional steps, thereby reducing the costly steps). Furthermore, by creating anti-reflective features by casting and eliminating high-temperature deposition, less expensive cover layers (e.g., non-curved polymer cover layers, curved polymer cover layers) with the desired anti-reflective properties can be fabricated for the eyepiece (e.g., to reduce ghost images), because high-temperature deposition processes can damage such cover layers (e.g., high-temperature deposition processes can damage polymer cover layers). In addition, the anti-reflective features 702 can be controlled across the cover layer to achieve the desired anti-reflective properties.

[0109] Figure 8 shows an exemplary cover layer 800 according to an embodiment of the present disclosure. In some embodiments, the cover layer 800 is a cover layer as described with respect to Figures 6A to 6C. Although the cover layer 800 is shown as not curved, it is understood that the antireflective features described with respect to Figure 8 can be fabricated for curved cover layers (e.g., the cover layers described with respect to Figures 6A to 6C).

[0110] In some embodiments, as shown, the cover layer 800 includes an anti-reflective feature 802, a protective film 804, and a film layer 806. The anti-reflective feature 802 may be fabricated on one or both sides of the cover layer. For brevity, some advantages of the anti-reflective feature described in relation to other figures are not described here. In some embodiments, the cover layer 800 comprises glass. In some embodiments, the anti-reflective feature 802 comprises a moth-eye structure. In some embodiments, the film layer 806 is a carrier film or an optically transparent adhesive (OCA) film for bonding or laminating the anti-reflective feature 802 (e.g., a moth-eye structure) to the cover layer. For example, a moth-eye structure comprises a pattern of subwavelength bumps that reduce reflection by generating an effective refractive index gradient between air and a medium (e.g., the cover layer substrate). The cover layer 800 advantageously utilizes the moth-eye structure, which is one of the most effective nanostructures for reducing reflection and ghost images. The geometric shape of the moth-eye structure can be spatially averaged over the height of the anti-reflective feature to achieve a gradual index change.

[0111] In some embodiments, the moth-eye structure is manufactured on a film (e.g., a base film). The base film is bonded or laminated to the substrate of the film layer 806 (e.g., a carrier film, OCA film) and the cover layer 800. If the moth-eye structure is bonded or laminated to the film layer 806, the base film may be removed (e.g., peeled off) leaving the moth-eye structure on the cover layer substrate. In some embodiments, the base film is a protective film 804 (e.g., to allow an additional protective layer for the cover layer 800 (e.g., for shipping, storage)) and is not removed after the moth-eye structure is formed on the cover layer substrate (e.g., it may be peeled off after shipping or storage). In some embodiments, the protective film 804 is advantageously hydrophobic, which can make the eyepiece with the cover layer 800 hydrophobic.

[0112] By fabricating anti-reflective features through bonding or lamination (e.g., by bonding or laminating a moth-eye structure), more expensive and / or complex anti-reflective feature fabrication processes such as high-temperature deposition and / or vacuum deposition may be unnecessary, reducing eyepiece manufacturing costs and / or complexity (e.g., by reducing expensive steps). Furthermore, the moth-eye structure material may be a different material from the cover substrate, allowing the anti-reflective features to include properties such as pencil hardness.

[0113] Figure 9 shows an exemplary cover layer 900 according to an embodiment of the present disclosure. In some embodiments, the cover layer 900 is the cover layer described with respect to Figures 6A to 6C. Although the cover layer 900 is shown as not curved, it is understood that the antireflective features described with respect to Figure 9 can be fabricated for curved cover layers (e.g., the cover layers described with respect to Figures 6A to 6C).

[0114] In some embodiments, as shown, the cover layer 900 includes an antireflection feature 902. The antireflection feature 902 may be fabricated on one or both sides of the cover layer. For brevity, some of the advantages of the antireflection feature described in relation to other figures will not be repeated here. The antireflection feature 902 may be coated (e.g., using a low refractive index coating, or using a coating that allows a gradual refractive index transition from low to high refractive index over the height of the antireflection feature). For example, the antireflection feature 902 may be fabricated by spin coating, dipping coating, spray coating, etc. A liquid precursor may be applied to form a single low refractive index film at atmospheric pressure. The liquid precursor is applied to one or both sides of a polymer cover layer (e.g., a curved cover layer, a non-curved cover layer) by spin coating, dipping coating, spray coating, etc. The liquid may be UV and / or heat-cured to produce a low refractive index coating.

[0115] For example, as shown in the figure, a liquid precursor droplet 904 can be deposited onto the cover layer (for example, at a velocity at the corresponding position to achieve the desired anti-reflective feature), and the cover layer can be rotated (for example, at a rotational speed to achieve the desired anti-reflective feature, as indicated by arrow 906) to fabricate the anti-reflective feature 902. An exemplary material for spin coating is Inkron IOC-501, which has a reflectivity in the range of 1.25 to 1.30.

[0116] By creating anti-reflective features through coating (e.g., by spin coating), more expensive and / or complex anti-reflective feature creation processes such as high-temperature deposition and / or vacuum deposition may be eliminated, thereby reducing eyepiece manufacturing costs and / or complexity (e.g., by reducing expensive steps).

[0117] Figures 10A to 10E show exemplary eyepiece characteristics according to embodiments of the present disclosure. Figure 10A shows exemplary characteristics of the cover layer 1000. In some embodiments, the cover layer 1000 is a cover layer described herein (for example, with respect to Figures 6 to 9 and Figure 12). The cover layer 1000 may comprise an anti-reflective feature 1002 having depth and a material 1004 (e.g., a substrate) having a refractive index n.

[0118] Figures 10B to 10E show reflectance versus depth (for example, of antireflection feature 1002) for different incident light wavelengths 1006 and different antireflection feature refractive indices. Depending on the desired antireflection requirements and wavelength, the depth and antireflection feature refractive index are determined accordingly. Antireflection features having the determined depth and refractive index can be manufactured using the methods disclosed herein (for example, those described with respect to Figures 7 to 9 and Figure 12).

[0119] Figure 10B shows the reflectance of incident light 1006 of blue (e.g., 455 nm), green (e.g., 525 nm), and red (e.g., 625 nm) for an exemplary antireflection feature with a refractive index of 1.25 versus the depth of the antireflection feature 1002. As shown in the figure, a depth of approximately 0.09 μm can result in a minimum reflectance of less than 0.005 for blue light, a depth of approximately 0.105 μm can result in a minimum reflectance of less than 0.005 for green light, and a depth of approximately 0.125 μm can result in a minimum reflectance of less than 0.005 for red light.

[0120] Figure 10C shows the reflectance versus depth of the antireflection feature 1002 for an exemplary antireflection feature with a refractive index of 1.32, with incident light 1006 of blue (e.g., 455 nm), green (e.g., 525 nm), and red (e.g., 625 nm). As shown in the figure, a depth of approximately 0.085 μm can result in a minimum reflectance close to zero for blue light, a depth of approximately 0.1 μm can result in a minimum reflectance close to zero for green light, and a depth of approximately 0.12 μm can result in a minimum reflectance close to zero for red light.

[0121] Figure 10D shows the reflectance of incident light 1006 of blue (e.g., 455 nm), green (e.g., 525 nm), and red (e.g., 625 nm) for an exemplary antireflection feature 1002 with a refractive index of 1.38, versus the depth of the antireflection feature 1002. As shown in the figure, a depth of approximately 0.08 μm can result in a minimum reflectance of approximately 0.002 for blue light, a depth of approximately 0.095 μm can result in a minimum reflectance of approximately 0.002 for green light, and a depth of approximately 0.11 μm can result in a minimum reflectance of approximately 0.002 for red light.

[0122] Figure 10E shows the reflectance of incident light 1006 of blue (e.g., 455 nm), green (e.g., 525 nm), and red (e.g., 625 nm) for an exemplary antireflection feature with a refractive index of 1.45 versus the depth of the antireflection feature 1002. As shown in the figure, a depth of approximately 0.08 μm can result in a minimum reflectance of less than 0.01 for blue light, a depth of approximately 0.09 μm can result in a minimum reflectance of less than 0.01 for green light, and a depth of approximately 0.11 μm can result in a minimum reflectance of less than 0.01 for red light.

[0123] Figure 11 shows an exemplary eyepiece stack according to embodiments of the present disclosure. In some embodiments, as shown, the eyepiece stack 1100 (e.g., an eyepiece stack for an MR system, an eyepiece stack for a wearable head device) comprises one or more anti-reflective features 1102, 1104, and 1106. In some embodiments, the eyepiece 1100 comprises different anti-reflective features. For example, a first anti-reflective feature (e.g., one of 1102, 1104, or 1106) and a second anti-reflective feature may be different (e.g., another of eyepieces 1102, 1104, or 1106). For example, the first anti-reflective feature may be more anti-reflective (e.g., have a lower reflectivity) than the second anti-reflective feature for light of a first wavelength. As another example, the second anti-reflective feature may be more anti-reflective (e.g., have a lower reflectivity) than the first anti-reflective feature for light of a second wavelength. Each anti-reflective feature may be determined based on the target wavelength corresponding to a particular eyepiece, and the determined anti-reflective features may be fabricated using the methods described herein (for example, as described with respect to Figures 7-9 and 12).

[0124] Figure 12 shows an exemplary method 1200 for manufacturing an eyepiece according to embodiments of the present disclosure. Although method 1200 is shown as including the steps described, it will be understood that it may include steps in a different order, additional steps, or fewer steps without departing from the scope of the present disclosure. For example, step 1204 may be performed before or after step 1202, or steps 1202 and 1204 may be performed simultaneously. For brevity, some advantages and features described with respect to Figures 5–11 will not be repeated here.

[0125] In some embodiments, Method 1200 includes providing waveguide layers for propagating light (Step 1202). For example, as described with reference to Figures 5 and 6A-6C, waveguide layers (e.g., waveguide layers 504, 604, 606, 608, 624, 626, 628, 644, 646, or 648) are provided. In some embodiments, the waveguide layers are curved. For example, as described with reference to Figures 5 and 6A-6C, the waveguide layers (e.g., waveguide layers 504, 604, 606, or 608) are curved.

[0126] In some embodiments, method 1200 includes optically coupling a projector to a waveguide layer. The projector generates light that propagates through the waveguide layer. For example, as described with reference to Figures 6A to 6C, a projector (e.g., projectors 612, 632, or 652) is optically coupled to a waveguide layer (e.g., waveguide layers 604, 606, 608, 624, 626, 628, 644, 646, or 648).

[0127] In some embodiments, Method 1200 includes providing a curved cover layer (step 1204). For example, as described with reference to Figures 6 to 9, a curved cover layer (e.g., cover layers 602, 622, 630, 642, 650, 700B, 800, or 900) is provided.

[0128] In some embodiments, Method 1200 includes fabricating anti-reflective features on a curved cover layer. For example, as described with respect to Figures 6 to 10, anti-reflective features (e.g., anti-reflective features 702, 802, 902, or 1002) are formed on the cover layer. In some embodiments, the anti-reflective features are fabricated by casting, using a moth-eye film, spin coating, dipping coating, or spray coating. For example, as described with respect to Figure 7, anti-reflective feature 702 is fabricated by casting. As another example, as described with respect to Figure 8, anti-reflective feature 802 is fabricated using a moth-eye film. As yet another example, as described with respect to Figure 9, anti-reflective feature 902 is fabricated by spin coating, dipping coating, or spray coating.

[0129] In some embodiments, the cover layer is curved toward the waveguide layer. For example, as described with respect to Figure 6B, the cover layer 630 is curved toward the waveguide layer. In some embodiments, the cover layer is curved away from the waveguide layer. For example, as described with respect to Figures 6A to 6C, the cover layer (e.g., cover layers 602, 622, 642, or 650) is curved away from the waveguide layer.

[0130] In some embodiments, the length of the curved cover layer is shorter than the length of the waveguide layer. For example, as described with respect to Figure 6C, the length of the cover layer 642 is shorter than the length of the waveguide layer (e.g., cut off). In some embodiments, method 1200 includes forming holes in the curved cover layer. For example, as described with respect to Figure 6C, holes 654 are formed in the cover layer 650.

[0131] In some embodiments, method 1200 includes providing a second cover layer. For example, as described with respect to Figures 6 to 9, a second cover layer (e.g., cover layers 610, 620, 630, 640, 650, 700A, 700B, 800, or 900) is provided. In some embodiments, the second cover layer is curved. For example, as described with respect to Figures 6 to 9, the second cover layer (e.g., cover layers 602, 622, 630, 642, 650, 700B, 800, or 900) is curved.

[0132] According to some embodiments, the eyepiece comprises a curved cover layer and a waveguide layer for propagating light.

[0133] According to some embodiments, the waveguide layer is curved.

[0134] According to some embodiments, the eyepiece further comprises a second cover layer.

[0135] According to some embodiments, the second cover layer is curved.

[0136] According to some embodiments, the curved cover layer has anti-reflective properties.

[0137] According to some embodiments, the curved cover layer has a second anti-reflective feature.

[0138] According to some embodiments, anti-reflective features are produced by casting, the use of moth-eye film, spin coating, dipping coating, or spray coating.

[0139] According to some embodiments, the cover layer is curved toward the waveguide layer.

[0140] According to some embodiments, the cover layer is curved so as to be separate from the waveguide layer.

[0141] According to some embodiments, the light propagating within the waveguide layer is generated from a projector.

[0142] According to some embodiments, the length of the curved cover layer is shorter than the length of the waveguide layer.

[0143] According to some embodiments, the curved cover layer is provided with holes.

[0144] According to some embodiments, a method for manufacturing an eyepiece includes providing a waveguide layer for propagating light and providing a curved cover layer.

[0145] According to some embodiments, the waveguide layer is curved.

[0146] According to some embodiments, the method further includes providing a second cover layer.

[0147] According to some embodiments, the second cover layer is curved.

[0148] According to some embodiments, the method further includes creating anti-reflective features on a curved cover layer.

[0149] According to some embodiments, anti-reflective features are produced by casting, the use of moth-eye film, spin coating, dipping coating, or spray coating.

[0150] According to some embodiments, the cover layer is curved toward the waveguide layer.

[0151] According to some embodiments, the cover layer is curved so as to be separate from the waveguide layer.

[0152] According to some embodiments, the method further includes optically coupling a projector to a waveguide layer, the projector generating light that propagates within the waveguide layer.

[0153] According to some embodiments, the length of the curved cover layer is shorter than the length of the waveguide layer.

[0154] According to some embodiments, the method further includes forming holes in the curved cover layer.

[0155] According to some embodiments, the wearable head device comprises a first eyepiece of any of the above eyepieces and a second eyepiece of any of the above eyepieces.

[0156] While the disclosed examples are adequately illustrated with reference to the accompanying drawings, it should be noted that various modifications and changes will be apparent to those skilled in the art. For example, elements of one or more implementations may be combined, removed, modified, or supplemented to form further implementations. Such modifications and changes should be understood to fall within the scope of the disclosed examples as defined by the accompanying claims.

Claims

1. It is an eyepiece, A first curved cover layer comprising a first anti-reflective feature and a second anti-reflective feature spaced apart from the first anti-reflective feature, A waveguide layer configured to propagate light generated by a projector, The second cover layer, A hole in the first curved cover layer or the second cover layer, wherein the hole is configured to optically couple the projector to the waveguide layer. Equipped with, The waveguide layer is positioned between the first curved cover layer and the second cover layer. The eyepiece wherein the first anti-reflective feature has a lower reflectivity of light at a first wavelength than the second anti-reflective feature.

2. The eyepiece according to claim 1, wherein the waveguide layer is curved.

3. The eyepiece according to claim 1, wherein the second cover layer is curved.

4. The eyepiece according to claim 1, wherein the first anti-reflective feature and the second anti-reflective feature are manufactured by casting, using a moth-eye film, spin coating, dipping coating, or spray coating.

5. The eyepiece according to claim 1, wherein the first curved cover layer is curved such that the central portion of the first curved cover layer separates from the waveguide layer.

6. The eyepiece according to claim 5, wherein the second cover layer is curved such that the central part of the second cover layer approaches the waveguide layer.

7. The eyepiece according to claim 1, wherein the length of the first curved cover layer is shorter than the length of the waveguide layer.

8. A method for manufacturing an eyepiece, wherein the method is A waveguide layer configured to propagate light received from a projector is provided, The invention provides a first curved cover layer, wherein the first curved cover layer comprises a first anti-reflective feature and a second anti-reflective feature spaced apart from the first anti-reflective feature. By providing a second cover layer, The first curved cover layer or the second cover layer is provided with a hole, the hole being configured to optically couple the waveguide layer to the projector. Includes, The waveguide layer is positioned between the first curved cover layer and the second cover layer. A method wherein the first anti-reflective feature has a lower reflectance of light at a first wavelength than the second anti-reflective feature.

9. The method according to claim 8, wherein the waveguide layer is curved.

10. The method according to claim 8, wherein the second cover layer is curved.

11. The method according to claim 8, wherein the first anti-reflective feature and the second anti-reflective feature are manufactured by casting, using a moth-eye film, spin coating, dipping coating, or spray coating.

12. The method according to claim 8, wherein the first curved cover layer is curved such that the central portion of the first curved cover layer separates from the waveguide layer.

13. The method according to claim 12, wherein the second cover layer is curved such that the central part of the second cover layer approaches the waveguide layer.

14. The method according to claim 8, wherein the length of the first curved cover layer is shorter than the length of the waveguide layer.

15. A wearable head device, wherein the wearable head device is The first eyepiece, The projector optically coupled to the first eyepiece and Equipped with, The first eyepiece mentioned above is A first curved cover layer comprising a first anti-reflective feature and a second anti-reflective feature spaced apart from the first anti-reflective feature, A waveguide layer configured to propagate light generated by the projector, The second cover layer, A hole in the first curved cover layer or the second cover layer, wherein the hole is configured to optically couple the projector to the waveguide layer. Equipped with, The waveguide layer is positioned between the first curved cover layer and the second cover layer. A wearable head device wherein the first anti-reflective feature has a lower light reflectivity at a first wavelength than the second anti-reflective feature.

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