Augmented and virtual reality display system with correlated in-coupling and out-coupling optical region

Abstract

To provide a suitable augmented and virtual reality display system.SOLUTION: An augmented reality and virtual reality display system and device are configured for efficient use of projected light. In some aspects, a display system includes a light projection system and a head-mounted display configured to project light into the eyes of a user to display virtual image content. The head-mounted display includes at least one waveguide comprising a plurality of in-coupling regions each configured to receive, from the light projection system, light corresponding to a portion of the user's field of view and to in-couple the light into the waveguide, and a plurality of out-coupling regions configured to out-couple the light out of the waveguide to display the virtual content, the out-coupling regions each configured to receive light from different ones of the in-coupling regions. In some implementations, each in-coupling region has one-to-one correspondence with a unique corresponding out-coupling region.SELECTED DRAWING: Figure 14A

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) Any application to which a claim of foreign or domestic priority is made that is identified in an Application Data Sheet filed with this application is hereby incorporated by reference under 37 CFR 1.57.

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 029312, filed May 22, 2020, and entitled "METHOD AND SYSTEM FOR DUAL PROJECTOR WAVEGUIDE DISPLAYS WITH WIDE FIELD OF VIEW," and U.S. Provisional Patent Application No. 63 / 050635, filed July 10, 2020, and entitled "AUGMENTED AND VIRTUAL REALITY DISPLAY SYSTEMS WITH CORRELATED IN-COUPLING AND OUT-COUPLING OPTICAL REGIONS FOR EFFICIENT LIGHT UTILIZATION," the contents of which are incorporated herein by reference in their entireties.

[0003] This application is incorporated herein by reference in its entirety, in whole or in part, in any of U.S. Patent Applications 2018 / 0275410, published on September 27, 2018, and entitled "DEPTH BASED FOVEATED RENDERING FOR DISPLAY SYSTEMS," U.S. Patent No. 10,573,042, published on February 25, 2020, and entitled "PERIOCULAR TEST FOR MIXED REALITY CALIBRATION," and U.S. Patent Application Publication No. 2019 / 0222830, published on July 18, 2019, and entitled "DISPLAY SYSTEMS AND METHODS FOR DETERMINING REGISTRATION BETWEEN A DISPLAY AND A USER'S EYES," and U.S. Patent Application Publication No. 2019 / 0222830, filed and issued on May 21, 2019, and entitled "IRIS BOUNDARY ESTIMATION USING CORNEA SYSTEMS AND METHODS FOR DETERMINING REGISTRATION BETWEEN A DISPLAY AND A USER'S EYES," all of which are hereby incorporated by reference in their entirety. No. 10,296,792, published on Feb. 23, 2017, entitled “EYELID SHAPE ESTIMATION USING EYE POSE MEASUREMENT”, U.S. Patent Publication No. 2017 / 0053165, published on Feb. 23, 2017, entitled “EYELID SHAPE ESTIMATION”, U.S. Patent Publication No. 2017 / 0053166, published on Aug. 8, 2019, entitled “EYE CENTER OF ROTATION DETERMINATION, DEPTH PLANE SELECTION,U.S. Patent Application Publication No. 2019 / 0243558, published on January 21, 2021, entitled "EYE CENTER OF ROTATION DETERMINATION WITH ONE OR MORE EYE TRACKING CAMERAS," International Publication No. WO2021 / 01166, published on April 26, 2018, entitled "SYSTEM AND METHOD FOR PRESENTING IMAGE CONTENT ON MULIPLE DEPTH PLANES BY PROVIDING MULTIPLE INTRA-PUPIL PARALLAX VIEWS," U.S. Patent Application Publication No. 2018 / 0113311, published on September 12, 2019, entitled "DISPLAY SYSTEM WITH LOW-LATENCY PUPIL PARALLAX VIEWS," This application is related to International Publication No. WO2019 / 173158, entitled "AUGMENTED REALITY SYSTEMS AND METHODS WITH VARIABLE FOCUS LENS ELEMENTS," U.S. Patent Application Publication No. 2017 / 0293145, published on October 12, 2017, entitled "AUGMENTED REALITY SYSTEMS AND METHODS WITH VARIABLE FOCUS LENS ELEMENTS," and U.S. Patent Application Publication No. 2018 / 0113311, published on April 26, 2018, entitled "SYSTEM AND METHOD FOR PRESENTING IMAGE CONTENT ON MULIPLE DEPTH PLANES BY PROVIDING MULTIPLE INTRA-PUPIL PARALLAX VIEWS."

[0004] The present disclosure relates to display systems, and more particularly to augmented and virtual reality display systems. [Background technology]

[0005] Modern computing and display technologies have facilitated the development of systems for so-called "virtual reality" or "augmented reality" experiences, in which digitally reproduced images or portions thereof are presented to a user in a manner that appears or can be perceived as real. Virtual reality, or "VR", scenarios typically involve the presentation of digital or virtual image information without transparency to other actual real-world visual inputs, and augmented reality, or "AR", scenarios typically involve the presentation of digital or virtual image information as an extension to the visualization of the real world around the user. Mixed reality, or "MR", scenarios are a type of AR scenario that typically involve virtual objects that are integrated into and responsive to the natural world. For example, MR scenarios may include AR image content that appears occluded by or is otherwise perceived to interact with objects in the real world.

[0006] Referring to FIG. 1, an augmented reality scene 10 is depicted. A user of the AR technology sees a real-world park-like setting 20 featuring people, trees, and buildings in the background, and a concrete platform 30. The user also perceives that they are "seeing" "virtual content," such as a robotic figure 40 standing on the real-world platform 30, and a flying cartoon-like avatar character 50 that appears to be an anthropomorphic bumblebee. These elements 50, 40 are "virtual" in that they do not exist in the real world. The human visual perception system is complex, making it difficult to produce AR technology that facilitates a comfortable, natural-feeling, and rich presentation of virtual image elements among other virtual or real-world image elements.

[0007] The systems and methods disclosed herein address various challenges associated with display technologies, including AR or VR technologies. Summary of the Invention [Means for solving the problem]

[0008] Aspects of the present disclosure will now be described in detail with respect to figures and various examples. However, those skilled in the art will appreciate that other configurations of the devices and methods disclosed herein would still fall within the scope of the present disclosure even if not described in as much detail. The various configuration aspects discussed are not intended to limit the scope of the present disclosure herein, which is instead defined by the claims that follow this description.

[0009] Described herein are various embodiments of display systems that project light to one or more eyes of a user and display virtual image content within the user's field of view, such as the embodiments listed below.

[0010] Example 1: A head-mountable display system configured to project light and display virtual image content, the display system comprising: a light projection system; and a head-mountable display configured to display virtual image content, the head-mountable display including at least one waveguide, the at least one waveguide comprising a plurality of internal coupling regions, each of the plurality of internal coupling regions configured to receive light having image information from the light projection system to form virtual image content and internally couple the light into the waveguide, and a plurality of external coupling regions, the plurality of external coupling regions configured to externally couple light out of the waveguide to display the virtual content, each of the plurality of external coupling regions configured to receive light from a different one of the internal coupling regions.

[0011] Example 2: The display system of example 1, wherein each inner bonding region of the plurality of inner bonding regions corresponds to a unique outer bonding region of the plurality of outer bonding regions and is configured to selectively direct light.

[0012] Example 3: A display system as described in Example 1 or 2, wherein each internal coupling region is a diffraction grating having at least one of a tilt, a grating orientation, a grating structure size, or a grating pitch selected to preferentially outcouple light internally coupled by the internal coupling region by the external coupling region corresponding to the internal coupling region.

[0013] Example 4: A display system described in any one of Examples 1-3, wherein the light coupling region is configured to redirect incident light from the optical projection system along the propagation direction through the waveguide at an angle for total internal reflection, and further comprises a light dispersing structure configured to redirect a portion of the light to propagate along an axis intersecting the propagation direction.

[0014] Example 5: The display system of any one of Examples 1-4, wherein the light dispersing structure and the plurality of outcoupling regions are disposed on opposing major surfaces of at least one waveguide.

[0015] Example 6: The display system of any one of Examples 1-5, wherein the plurality of internal coupling regions comprises a diffraction grating.

[0016] Example 7: The display system of any one of Examples 1-6, wherein each of the plurality of in-coupling regions has a different grating pitch than at least one other in-coupling region of the waveguide.

[0017] Example 8: A display system described in any one of Examples 1-7, wherein the different grating pitches change the total internal reflection angle at which light internally coupled into the waveguide undergoes total internal reflection towards the waveguide towards an associated external coupling region of the multiple external coupling regions.

[0018] Example 9: A display system as described in any one of Examples 1-6, wherein each of the plurality of internal coupling regions has a different lattice orientation in the plane of the waveguide than at least one other internal coupling region of the waveguide.

[0019] Example 10: A display system described in any one of Examples 1-9, wherein different grating orientations change the angle at which light is coupled into the waveguide such that the light propagates toward an intended outcoupling region of the multiple outcoupling regions.

[0020] Example 11: A display system described in any one of Examples 1-10, wherein each of the multiple internal coupling regions has a different inclination relative to the plane of the waveguide than at least one other internal coupling region of the waveguide.

[0021] Example 12: The display system of any one of Examples 1-11, wherein the internal bonding regions are spaced apart from each other.

[0022] Example 13: The display system of any one of Examples 1-12, wherein the light in-coupling regions are arranged in a line around at least one side of the plurality of out-coupling regions.

[0023] Example 14: A display system described in any one of Examples 1-13, wherein each of the external coupling regions defines a stripe across the waveguide, the stripe extending along an axis that intersects the rows of the internal coupling regions.

[0024] Example 15: The display system of any one of Examples 1-14, wherein the outcoupling region defines a grid pattern across the waveguide.

[0025] Example 16: A display system described in any one of Examples 1-15, wherein each of a plurality of internal coupling regions is arranged to internally couple light and direct the light to propagate within the waveguide by total internal reflection along a different direction than at least one other internal coupling region of the waveguide.

[0026] Example 17: A display system described in any one of Examples 1-16, wherein at least one internal coupling region adjacent a lateral edge of at least one external coupling region is configured to internally couple light along a range of angles symmetrically arranged around an inwardly biased axis.

[0027] Example 18: A display system described in any one of Examples 1-17, wherein at least two of the multiple internal bonding regions are positioned along different sides of at least one of the multiple external bonding regions.

[0028] Example 19: A display system described in any one of Examples 1-18, wherein the multiple internal coupling regions have internal coupling optical elements on at least three sides that surround at least one of the multiple external coupling regions.

[0029] Example 20: A display system described in any one of Examples 1-19, wherein the light projection system comprises a light source and a movable light launcher configured to direct image light to individual ones of the internal coupling regions.

[0030] Example 21: A display system described in any one of Examples 1-20, wherein the head-mountable display comprises a plurality of waveguides forming a waveguide stack, each of the waveguides having a plurality of internal coupling regions and external coupling regions, and the internal coupling region of each of the waveguides is displaced laterally as seen in a front plan view when viewed from the direction of internal coupling light incident on the internal coupling region.

[0031] Example 22: A display system described in any one of Examples 1-21, wherein the external coupling regions of the same waveguide are configured to output light with the same wavefront divergence, and the external coupling regions of different waveguides are configured to output light with a different amount of wavefront divergence than the external coupling regions of at least one other waveguide, the different amounts of wavefront divergence corresponding to different depth planes.

[0032] Example 23: A display system described in any one of Examples 1-212, wherein the internal coupling region of each waveguide is configured to internally couple light in a range of wavelengths corresponding to the same primary color, and the internal coupling regions of some waveguides are configured to internally couple light in a range of wavelengths corresponding to a different primary color than the internal coupling regions of other waveguides.

[0033] Example 24: A display system described in any one of Examples 1-23, wherein the optical projection system comprises a light source having an array of light emitters, a spatial light modulator configured to modulate light from the light source, and a projection optical system mounted on a frame and configured to direct light from the spatial light modulator to an internal coupling region, wherein the display system is configured to activate different light emitters and provide virtual image content on different depth planes, and the display system is configured to provide a relatively large distance between individual light emitters of the multiple light emitters to provide virtual image content on a relatively near depth plane, and to provide a relatively small distance between individual light emitters of the multiple light emitters to provide virtual image content on a relatively far depth plane.

[0034] Example 25: A display system described in any one of Examples 1-24, configured to sequentially activate each of the multiple light emitters at different times, and the display system configured to synchronize the activation of each light emitter with the display of different parallaxically disparate intrapupillary images.

[0035] Example 26: The display system of any one of Examples 1-245, wherein the light source is a microdisplay and the light emitter is a light emitting diode.

[0036] Example 27: The display system of any one of Examples 1-26, further comprising a variable focus lens element on the opposing side of the waveguide.

[0037] Example 28: A display system described in any one of Examples 1-27, wherein the optical projection system comprises a plurality of projectors, the projectors of the plurality of projectors being configured to provide image content for less than a subdivided portion of the FOV of the head-mounted display.

[0038] Example 29: A display system comprising: a light projection system; a head-mountable display configured to project light into a user's eye and display virtual image content, the head-mountable display comprising at least one waveguide, the head-mountable display comprising at least one waveguide having a plurality of light in-coupling regions configured to receive light from the light projection system and a plurality of light out-coupling regions configured to output light to the user's eye; and processing electronics in communication with the display and an inwardly facing imaging system, the processing electronics comprising one or more processors and one or more computer storage media, the one or more computer storage media storing instructions that, when executed by the one or more processors, cause the one or more processors to perform operations including determining a light out-coupling region associated with an eye posture of the eye; and providing instructions for directing light from the light projection system to the light in-coupling region associated with the determined light out-coupling region.

[0039] Example 30: A display system as described in Example 29, wherein determining the light external coupling area includes determining an intersection point between the line of sight of the eye and one of the multiple light external coupling areas.

[0040] Example 31: The display system of example 29 or 30, wherein the optical incoupling region is arranged in a line around at least one side of the plurality of outcoupling regions.

[0041] Example 32: A display system as described in Example 29, wherein the light projection system comprises at least one light source and at least one movable light emitter configured to output image light.

[0042] Example 33: The display system of any one of Examples 29-32, wherein at least one movable light launcher comprises a scanning mirror.

[0043] Example 34: The display system of any one of Examples 29-33, wherein at least one movable light launcher comprises a scanning fiber launcher.

[0044] Example 35: A display system described in any one of Examples 29-34, wherein the optical projection system comprises at least one light source and at least one spatial light modulator configured to modulate light from the light source.

[0045] Example 36: A display system described in any one of Examples 29-35, wherein the head-mounted display is configured to display virtual objects on multiple depth planes.

[0046] Example 37: A display system described in any one of Examples 29-36, wherein the operation includes injecting a set of parallax-dissimilar intrapupillary images of a virtual object into the eye and displaying the virtual object on one of the depth planes.

[0047] Example 38: A display system described in any one of Examples 29-37, wherein the operation includes casting each of the set of parallaxly disparate intra-pupillary images within a flicker fusion threshold.

[0048] Example 39: A display system described in any one of Examples 29-39, wherein the operation includes providing instructions for directing light to multiple internal coupling elements within the optical internal coupling regions of multiple internal coupling regions associated with the determined optical external coupling region.

[0049] Example 40: A display system described in any one of Examples 29-39, further comprising at least one variable focus lens element on the user side of at least one waveguide, wherein a first variable focus lens element is configured to modify the projected light and correct refractive error of the user's eye.

[0050] Example 41: A display system described in any one of Examples 29-40, wherein the operation further includes determining an eye fixation point and applying a correction corresponding to the fixation point.

[0051] Example 42: A display system as described in any one of Examples 29-41, further comprising an inwardly facing imaging system configured to capture an image of one or more of the user's eyes, wherein operations include receiving an image of the user's eyes captured by the inwardly facing imaging system and identifying an eye posture based on the received image.

[0052] Example 43: A display system described in any one of Examples 29-42, wherein at least one waveguide is one of a plurality of waveguides forming a waveguide stack, each of the waveguides having a plurality of internal coupling regions and external coupling regions, and the internal coupling region of each of the waveguides is laterally displaced as seen in a front plan view when viewed from the direction of internal coupling light incident on the internal coupling region.

[0053] Example 44: A display system described in any one of Examples 29-43, wherein the external coupling regions of the same waveguide are configured to output light with the same wavefront divergence, and the external coupling regions of different waveguides are configured to output light with a different amount of wavefront divergence than the external coupling regions of at least one other waveguide, the different amounts of wavefront divergence corresponding to different depth planes.

[0054] Example 45: A display system described in any one of Examples 29-44, wherein the internal coupling region of each waveguide is configured to internally couple light in a range of wavelengths corresponding to the same primary color, and the internal coupling regions of some waveguides are configured to internally couple light in a range of wavelengths corresponding to a different primary color than the internal coupling regions of other waveguides.

[0055] Example 46: A display system described in any one of Examples 29-45, wherein the optical projection system comprises a plurality of projectors, the projectors of the plurality of projectors being configured to provide image content for less than a subdivided portion of the FOV of the head-mounted display.

[0056] Example 47: A display system comprising: a light projection system; a head-mounted display configured to project light into a user's eye and display virtual image content, the head-mounted display comprising at least one waveguide, the head-mounted display comprising at least one waveguide having a plurality of light in-coupling regions configured to receive light from the light projection system and a plurality of light out-coupling regions configured to output light to the user's eye; and processing electronics in communication with the display, the processing electronics comprising one or more processors and one or more computer storage media, the one or more computer storage media storing instructions that, when executed by the one or more processors, cause the one or more processors to perform operations including determining a location for a virtual object within a user's field of view; identifying an out-coupling region corresponding to the location; and providing instructions for directing light from the light projection system to the light in-coupling region associated with the determined light out-coupling region.

[0057] Example 48: A display system as described in Example 47, wherein identifying the external binding region includes determining an eye posture of the eye and determining an external binding region that overlaps a location to be occupied by a virtual object within the field of view.

[0058] Example 49: A display system as described in Example 47 or 48, wherein the operation includes providing movement for a virtual object.

[0059] Example 50: A display system described in any one of Examples 47-49, wherein the operation includes providing temporal changes in visual properties of a virtual object over time, the visual properties comprising one or more of color, size, and brightness.

[0060] Example 51: A display system described in any one of Examples 47-50, wherein the optical in-coupling region is arranged in a row around at least one side of the plurality of out-coupling regions.

[0061] Example 52: A display system described in any one of Examples 47-52, wherein the light projection system comprises at least one light source and at least one movable light emitter configured to output image light.

[0062] Example 53: The display system of any one of Examples 47-52, wherein at least one movable light introducer comprises a scanning mirror.

[0063] Example 54: A display system described in any one of Examples 47-52, wherein at least one movable light launcher comprises a scanning fiber launcher.

[0064] Example 55: A display system described in any one of Examples 47-51, wherein the optical projection system comprises at least one light source and at least one spatial light modulator configured to modulate light from the light source.

[0065] Example 56: A display system described in any one of Examples 47-55, wherein the head-mounted display is configured to display virtual objects on multiple depth planes.

[0066] Example 57: A display system described in any one of Examples 47-56, wherein the operation includes injecting a set of parallax-dissimilar intrapupillary images of a virtual object into the eye and displaying the virtual object on one of the depth planes.

[0067] Example 58: A display system described in any one of Examples 47-56, wherein the operation includes providing instructions for directing light to multiple internal coupling elements within an optical internal coupling region of a multiple internal coupling region associated with the determined optical external coupling region.

[0068] Example 59: A display system described in any one of Examples 47-56, further comprising at least one variable focus lens element on the user side of at least one waveguide, wherein a first variable focus lens element is configured to modify the projected light and correct refractive error of the user's eye.

[0069] Example 60: A display system as described in any one of Examples 47-59, further comprising an inwardly facing imaging system configured to capture an image of one or more of the user's eyes, wherein operations include receiving an image of the user's eyes captured by the inwardly facing imaging system and identifying an eye posture based on the received image.

[0070] Example 61: A display system described in any one of Examples 47-60, wherein at least one waveguide is one of a plurality of waveguides forming a waveguide stack, each of the waveguides having a plurality of internal coupling regions and external coupling regions, and the internal coupling region of each of the waveguides is displaced laterally as seen in a front plan view when viewed from the direction of internal coupling light incident on the internal coupling region.

[0071] Example 62: A display system described in any one of Examples 47-61, wherein the external coupling regions of the same waveguide are configured to output light with the same wavefront divergence, and the external coupling regions of different waveguides are configured to output light with a different amount of wavefront divergence than the external coupling regions of at least one other waveguide, the different amounts of wavefront divergence corresponding to different depth planes.

[0072] Example 63: A display system described in any one of Examples 47-62, wherein the internal coupling region of each waveguide is configured to internally couple light in a range of wavelengths corresponding to the same primary color, and the internal coupling regions of some waveguides are configured to internally couple light in a range of wavelengths corresponding to a different primary color than the internal coupling regions of other waveguides.

[0073] Example 64: The display system of any one of Examples 47-63, wherein the internal coupling region comprises a diffraction grating.

[0074] Example 65: The display system of any one of Examples 47-64, wherein the outcoupling region comprises a diffraction grating.

[0075] Example 66: A display system described in any one of Examples 47-65, wherein the optical projection system comprises a plurality of projectors, the projectors of the plurality of projectors being configured to provide image content for less than a subdivided portion of the FOV of the head-mounted display.

[0076] Example 67: A head-mountable display system configured to project light and display virtual image content, the display system comprising: a light projection system; and a head-mountable display configured to display virtual image content, the head-mountable display including at least one waveguide, the at least one waveguide having a plurality of internal coupling regions adjacent at least one lateral edge of the at least one waveguide, each waveguide configured to receive light having image information to form the virtual image content from the light projection system and internally couple the light into the waveguide.

[0077] Example 68: A display system as described in Example 67, further comprising a plurality of external coupling regions configured to externally couple light out of the waveguide and display virtual content, each of the plurality of external coupling regions configured to receive light from a different one of the internal coupling regions.

[0078] Example 69: A display system described in Example 67 or 68, wherein at least two of the multiple internal bonding regions are positioned along different lateral edges of at least one external bonding region of the multiple external bonding regions.

[0079] Example 70: The display system of any one of Examples 67-69, wherein the multiple inner bonding regions surround the multiple outer bonding regions.

[0080] Example 71: A display system described in any one of Examples 67-70, wherein each internal bonding region of the multiple internal bonding regions corresponds to a unique external bonding region of the multiple external bonding regions and is configured to selectively direct light.

[0081] Example 72: A display system described in any one of Examples 67-71, wherein the optical coupling region is configured to redirect incident light from the optical projection system along the propagation direction through the waveguide at an angle for total internal reflection, and further comprises an optical dispersion structure configured to redirect a portion of the light to propagate along an axis intersecting the propagation direction.

[0082] Example 73: The display system of any one of Examples 67-72, wherein the light dispersing structure and the plurality of outcoupling regions are disposed on opposing major surfaces of at least one waveguide.

[0083] Example 74: The display system of any one of Examples 67-73, wherein the external coupling region defines a grid pattern across the waveguide.

[0084] Example 75: A display system described in any one of Examples 67-74, wherein the head-mountable display comprises a plurality of waveguides forming a waveguide stack, each of the waveguides having a plurality of internal coupling regions and external coupling regions, and the internal coupling region of each of the waveguides is displaced laterally as seen in a front plan view when viewed from the direction of internal coupling light incident on the internal coupling region.

[0085] Example 76: A display system described in any one of Examples 67-75, wherein the external coupling regions of the same waveguide are configured to output light with the same wavefront divergence, and the external coupling regions of different waveguides are configured to output light with a different amount of wavefront divergence than the external coupling regions of at least one other waveguide, the different amounts of wavefront divergence corresponding to different depth planes.

[0086] Example 77: A display system described in any one of Examples 67-76, wherein the internal coupling region of each waveguide is configured to internally couple light in a range of wavelengths corresponding to the same primary color, and the internal coupling regions of some waveguides are configured to internally couple light in a range of wavelengths corresponding to a different primary color than the internal coupling regions of other waveguides.

[0087] Example 78: The display system of any one of Examples 67-77, wherein the multiple internal coupling regions comprise a diffraction grating.

[0088] Example 79: A display system described in any one of Examples 67-78, wherein each of the multiple internal coupling regions has a different grating pitch than at least one other internal coupling region of the waveguide.

[0089] Example 80: A display system described in any one of Examples 67-79, wherein each of the multiple internal coupling regions has a different lattice orientation in the plane of the waveguide than at least one other internal coupling region of the waveguide.

[0090] Example 81: A display system described in any one of Examples 67-80, wherein each of the multiple internal coupling regions has a different inclination relative to the plane of the waveguide than at least one other internal coupling region of the waveguide.

[0091] Example 82: The display system of any one of Examples 67-81, wherein the internal bonding regions are spaced apart from each other.

[0092] Example 83: A display system described in any one of Examples 67-82, wherein each of the multiple internal coupling regions is arranged to internally couple light and direct the light to propagate within the waveguide along a different direction than at least one other internal coupling region of the waveguide by total internal reflection.

[0093] Example 84: A display system described in any one of Examples 67-83, wherein the light projection system comprises at least one light source and at least one movable light emitter configured to direct image light to each of the internal coupling regions.

[0094] Example 85: A display system described in any one of Examples 67-84, wherein the optical projection system comprises at least one light source having an array of light emitters, at least one spatial light modulator configured to modulate light from the light source, and a projection optical system mounted on a frame and configured to direct light from the spatial light modulator to an internal coupling region, wherein the display system is configured to activate different light emitters and provide virtual image content on different depth planes, and the display system is configured to provide a relatively large distance between individual light emitters of the multiple light emitters to provide virtual image content on a relatively near depth plane, and to provide a relatively small distance between individual light emitters of the multiple light emitters to provide virtual image content on a relatively far depth plane.

[0095] Example 86: A display system described in any one of Examples 67-86, configured to sequentially activate each of the multiple light emitters at different times, and the display system configured to synchronize the activation of each light emitter with the display of different parallaxically disparate intrapupillary images.

[0096] Example 87: The display system of any one of Examples 67-86, further comprising variable focus lens elements on opposing side edges of the waveguide.

[0097] Example 88: A display system described in any one of Examples 67-87, wherein the optical projection system comprises a plurality of projectors, the projectors of the plurality of projectors being configured to provide image content for a subdivided portion or less of the FOV of the head-mounted display.

[0098] Details of one or more implementations of the subject matter described herein are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, drawings, and claims. Neither this description nor the following detailed description is intended to limit the scope of the inventive subject matter. The present invention provides, for example, the following: (Item 1) 1. A head-mountable display system configured to project light and display virtual image content, the display system comprising: A light projection system; 1. A head mountable display configured to display virtual image content, the head mountable display including at least one waveguide, the at least one waveguide comprising: a plurality of incoupling regions, each of the plurality of incoupling regions configured to receive light having image information for forming the virtual image content from the light projection system and incoupling the light into the waveguide; a plurality of external coupling regions configured to externally couple the light out of the waveguide and display the virtual content, each of the plurality of external coupling regions configured to receive light from a different one of the internal coupling regions; A head-mountable display comprising: A display system comprising: (Item 2) 2. The display system of claim 1, wherein each inner bonding region of the plurality of inner bonding regions corresponds to a unique outer bonding region of the plurality of outer bonding regions and is configured to selectively direct light. (Item 3) 3. The display system of claim 2, wherein each internal coupling region is a diffraction grating having at least one of a tilt, a grating orientation, a grating structure size, or a grating pitch selected to preferentially outcouple light inwardly coupled by the internal coupling region by the external coupling region corresponding to the internal coupling region. (Item 4) 2. The display system of claim 1, wherein the light coupling region is configured to redirect incident light from the optical projection system through the waveguide along a propagation direction at an angle for total internal reflection, and further comprises a light dispersing structure configured to redirect a portion of the light to propagate along an axis intersecting the propagation direction. (Item 5) Item 5. The display system of item 4, wherein the light dispersing structure and the plurality of outcoupling regions are disposed on opposing major surfaces of the at least one waveguide. (Item 6) Item 13. The display system of item 1, wherein the plurality of internal coupling regions comprise a diffraction grating. (Item 7) 7. The display system of claim 6, wherein each of the plurality of internal coupling regions has a different grating pitch than at least one other internal coupling region of the waveguide. (Item 8) 8. The display system of claim 7, wherein the different grating pitches change the total internal reflection angle at which light internally coupled into the waveguide undergoes total internal reflection toward the waveguide toward an associated external coupling region of the plurality of external coupling regions. (Item 9) 7. The display system of claim 6, wherein each of the plurality of internal coupling regions has a different lattice orientation in the plane of the waveguide than at least one other internal coupling region of the waveguide. (Item 10) 10. The display system of claim 9, wherein the different grating orientations change the angle at which light is coupled into the waveguide so that the light propagates toward an intended outcoupling region of the multiple outcoupling regions. (Item 11) 2. The display system of claim 1, wherein each of the plurality of internal coupling regions has a different inclination relative to a plane of the waveguide than at least one other internal coupling region of the waveguide. (Item 12) Item 2. The display system of item 1, wherein the internal bonding regions are spaced apart from each other. (Item 13) Item 2. The display system of item 1, wherein the light in-coupling regions are arranged in a row around at least one side of the plurality of out-coupling regions. (Item 14) Item 14. The display system of item 13, wherein each of the outer coupling regions defines a stripe across the waveguide, the stripe extending along an axis that intersects the rows of the inner coupling regions. (Item 15) Item 2. The display system of item 1, wherein the external coupling regions define a grid pattern across the waveguide. (Item 16) 2. The display system of claim 1, wherein each of the plurality of internal coupling regions is arranged to internally couple light and direct the light to propagate within the waveguide by total internal reflection along a different direction than at least one other internal coupling region of the waveguide. (Item 17) Item 17. The display system of item 16, wherein at least one internal coupling region proximate a lateral edge of the at least one external coupling region is configured to internally couple light along a range of angles symmetrically disposed about an inwardly biased axis. (Item 18) 2. The display system of claim 1, wherein at least two of the plurality of internal bonding regions are disposed along different sides of at least one of the plurality of external bonding regions. (Item 19) 20. The display system of claim 18, wherein the plurality of internal coupling regions comprises an internal coupling optical element on at least three sides that surrounds at least one of the plurality of external coupling regions. (Item 20) Item 2. The display system of item 1, wherein the light projection system comprises a light source and a movable light launcher configured to direct image light to individual ones of the internal coupling regions. (Item 21) the head mountable display comprises a plurality of waveguides forming a waveguide stack, each of the waveguides comprising a plurality of the inner coupling regions and the outer coupling regions; the incoupling region of each of the waveguides is laterally displaced, as viewed in a front plan view, when viewed from the direction of incoupling light incident on the incoupling region. Item 1. A display system according to item 1. (Item 22) the outcoupling regions of the same waveguide are configured to output light with the same wavefront divergence; the outcoupling regions of the different waveguides are configured to output light with a different amount of wavefront divergence than the outcoupling regions of the at least one other waveguide; The different amounts of wavefront divergence correspond to different depth planes. 22. The display system according to item 21. (Item 23) the incoupling region of each waveguide is configured to incoupling light in a range of wavelengths corresponding to the same primary color; the incoupling regions of some of the waveguides are configured to incoupling light in ranges of wavelengths corresponding to different primary colors from the incoupling regions of other waveguides; 22. The display system according to item 21. (Item 24) The optical projection system comprises: a light source comprising an array of light emitters; a spatial light modulator configured to modulate light from the light source; a projection optical system mounted on a frame and configured to direct light from the spatial light modulator to the incoupling region; Equipped with The display system is configured to activate different light emitters to provide the virtual image content on different depth planes, the display system comprising: providing a relatively large distance between individual light emitters of the plurality of light emitters to provide the virtual image content on a relatively close depth plane; providing a relatively small distance between individual light emitters of the plurality of light emitters to provide the virtual image content on a relatively far depth surface; 2. The display system of item 1, configured to: (Item 25) 25. The display system of claim 24, wherein each of the light emitters of the plurality of light emitters is configured to be sequentially activated at a different time, and the display system is configured to synchronize activation of each light emitter with display of different parallaxically disparate intrapupillary images. (Item 26) 25. The display system of claim 24, wherein the light source is a microdisplay and the light emitter is a light emitting diode. (Item 27) Item 13. The display system of item 1, further comprising a variable focus lens element on an opposing side of the waveguide. (Item 28) 2. The display system of claim 1, wherein the optical projection system comprises a plurality of projectors, the projectors of the plurality of projectors being configured to provide image content for at most a subdivided portion of the FOV of the head mounted display. (Item 29) 1. A display system comprising: A light projection system; 1. A head-mountable display configured to project light into a user's eye and display virtual image content, the head-mountable display comprising: At least one waveguide, a plurality of light in-coupling regions configured to receive light from the optical projection system; a plurality of light out-coupling regions configured to output light to the user's eye; At least one waveguide A head mounted display comprising: and processing electronics in communication with the display and the inwardly facing imaging system, the processing electronics comprising one or more processors and one or more computer storage media having instructions stored thereon that, when executed by the one or more processors, cause the one or more processors to: determining a light outcoupling area associated with an eye posture of the eye; providing instructions for directing light from the optical projection system to an optical in-coupling region associated with the determined optical out-coupling region; and processing electronics for performing operations including: A display system comprising: (Item 30) 30. The display system of claim 29, wherein determining the light outcoupling area includes determining an intersection point between a line of sight of the eye and one of the plurality of light outcoupling areas. (Item 31) 30. The display system of claim 29, wherein the light in-coupling regions are arranged in a row around at least one side of the plurality of out-coupling regions. (Item 32) 30. The display system of claim 29, wherein the light projection system comprises at least one light source and at least one movable light launcher configured to output image light. (Item 33) Item 33. The display system of item 32, wherein the at least one movable light launcher comprises a scanning mirror. (Item 34) Item 33. The display system of item 32, wherein the at least one movable light launcher comprises a scanning fiber launcher. (Item 35) 30. The display system of item 29, wherein the light projection system comprises at least one light source and at least one spatial light modulator configured to modulate light from the light source. (Item 36) 30. The display system of item 29, wherein the head-mounted display is configured to display virtual objects on multiple depth planes. (Item 37) Item 37. The display system of item 36, wherein the operations include projecting a set of parallaxically disparate intra-pupillary images of the virtual object into the eye and displaying the virtual object on one of the depth planes. (Item 38) Item 38. The display system of item 37, wherein the action includes casting each of the set of parallaxly disparate intrapupillary images within a flicker fusion threshold. (Item 39) 37. The display system of claim 36, wherein the operation includes providing instructions for directing light to a plurality of internal coupling elements within an optical internal coupling region of the plurality of internal coupling regions associated with the determined optical external coupling region. (Item 40) Item 37. The display system of item 36, further comprising at least one variable focus lens element on a user side of the at least one waveguide, a first variable focus lens element configured to modify the projected light and correct refractive error of the user's eye. (Item 41) Item 41. The display system of item 40, wherein the operations further include determining a fixation point of the eye and applying a correction corresponding to the fixation point. (Item 42) and an inwardly facing imaging system configured to capture an image of one or more of the user's eyes, said operation further comprising: receiving an image of the user's eye captured by the inwardly facing imaging system; identifying the eye posture based on the received image; 30. The display system of item 29, comprising: (Item 43) the at least one waveguide is one of a plurality of waveguides forming a waveguide stack, each of the waveguides comprising a plurality of the inner and outer coupling regions; the incoupling region of each of the waveguides is laterally displaced, as viewed in a front plan view, when viewed from the direction of incoupling light incident on the incoupling region. 30. The display system of item 29. (Item 44) the outcoupling regions of the same waveguide are configured to output light with the same wavefront divergence; the outcoupling regions of the different waveguides are configured to output light with a different amount of wavefront divergence than the outcoupling regions of the at least one other waveguide; The different amounts of wavefront divergence correspond to different depth planes. Item 44. The display system according to item 43. (Item 45) the incoupling region of each waveguide is configured to incoupling light in a range of wavelengths corresponding to the same primary color; the incoupling regions of some of the waveguides are configured to incoupling light in ranges of wavelengths corresponding to different primary colors from the incoupling regions of other waveguides; Item 44. The display system according to item 43. (Item 46) 30. The display system of claim 29, wherein the optical projection system comprises a plurality of projectors, the projectors of the plurality of projectors being configured to provide image content for at most a subdivided portion of the FOV of the head mounted display. (Item 47) 1. A display system comprising: A light projection system; 1. A head mounted display configured to project light into a user's eye and display virtual image content, the head mounted display comprising: At least one waveguide, a plurality of optical in-coupling regions configured to receive light from the optical projection system; a plurality of light out-coupling regions configured to output light to the user's eye; At least one waveguide A head mounted display comprising: and processing electronics in communication with the display, the processing electronics comprising one or more processors and one or more computer storage media, the one or more computer storage media storing instructions that, when executed by the one or more processors, cause the one or more processors to: determining a location for a virtual object within a field of view of the user; identifying an external binding region corresponding to said location; providing instructions for directing light from the optical projection system to an optical in-coupling region associated with the determined optical out-coupling region; and processing electronics for performing operations including: A display system comprising: (Item 48) Identifying the external binding region comprises: determining an eye posture of the eye; determining an outer bounded region overlapping the location to be occupied by the virtual object within the field of view; Item 48. The display system of item 47, comprising: (Item 49) Item 48. The display system of item 47, wherein the action includes providing movement for the virtual object. (Item 50) Item 48. The display system of item 47, wherein the operation includes providing temporal changes in visual properties of the virtual object over time, the visual properties comprising one or more of color, size, and brightness. (Item 51) Item 48. The display system of item 47, wherein the light in-coupling regions are arranged in a row around at least one side of the plurality of out-coupling regions. (Item 52) Item 48. The display system of item 47, wherein the light projection system comprises at least one light source and at least one movable light launcher configured to output image light. (Item 53) Item 53. The display system of item 52, wherein the at least one movable light introducer comprises a scanning mirror. (Item 54) Item 53. The display system of item 52, wherein the at least one movable light launcher comprises a scanning fiber launcher. (Item 55) Item 48. The display system of item 47, wherein the light projection system comprises at least one light source and at least one spatial light modulator configured to modulate light from the light source. (Item 56) Item 48. The display system of item 47, wherein the head-mounted display is configured to display virtual objects on multiple depth planes. (Item 57) 57. The display system of claim 56, wherein the operations include projecting a set of parallaxically disparate intrapupillary images of the virtual object into the eye and displaying the virtual object on one of the depth planes. (Item 58) 57. The display system of claim 56, wherein the operation includes providing instructions for directing light to a plurality of internal coupling elements within an optical internal coupling region of the plurality of internal coupling regions associated with the determined optical external coupling region. (Item 59) Item 57. The display system of item 56, further comprising at least one variable focus lens element on a user side of the at least one waveguide, a first variable focus lens element configured to modify the projected light and correct for refractive error of the user's eye. (Item 60) and an inwardly facing imaging system configured to capture an image of one or more of the user's eyes, said operation further comprising: receiving an image of the user's eye captured by the inwardly facing imaging system; identifying the eye posture based on the received image; Item 48. The display system of item 47, comprising: (Item 61) the at least one waveguide is one of a plurality of waveguides forming a waveguide stack, each of the waveguides comprising a plurality of the inner and outer coupling regions; the incoupling region of each of the waveguides is laterally displaced, as viewed in a front plan view, when viewed from the direction of incoupling light incident on the incoupling region. Item 48. The display system according to item 47. (Item 62) the outcoupling regions of the same waveguide are configured to output light with the same wavefront divergence; the outcoupling regions of the different waveguides are configured to output light with a different amount of wavefront divergence than the outcoupling regions of the at least one other waveguide; The different amounts of wavefront divergence correspond to different depth planes. Item 48. The display system according to item 47. (Item 63) the incoupling region of each waveguide is configured to incoupling light in a range of wavelengths corresponding to the same primary color; the incoupling regions of some of the waveguides are configured to incoupling light in ranges of wavelengths corresponding to different primary colors from the incoupling regions of other waveguides; Item 48. The display system according to item 47. (Item 64) Item 48. The display system of item 47, wherein the internal coupling region comprises a diffraction grating. (Item 65) Item 48. The display system of item 47, wherein the outcoupling region comprises a diffraction grating. (Item 66) Item 47. The display system of item 46, wherein the optical projection system comprises a plurality of projectors, the projectors of the plurality of projectors being configured to provide image content for at most a subdivided portion of the FOV of the head mounted display. (Item 67) 1. A head-mountable display system configured to project light and display virtual image content, the display system comprising: A light projection system; 1. A head mountable display configured to display virtual image content, the head mountable display including at least one waveguide, the at least one waveguide comprising: a plurality of incoupling regions proximate at least one side edge of the at least one waveguide, each waveguide configured to receive light having image information from the optical projection system to form the virtual image content and incoupling the light into the waveguide; A head-mountable display comprising: A display system comprising: (Item 68) Item 68. The display system of item 67, further comprising a plurality of external coupling regions configured to externally couple the light out of the waveguide and display the virtual content, each of the plurality of external coupling regions configured to receive light from a different one of the internal coupling regions. (Item 69) Item 68. The display system of item 67, wherein at least two of the plurality of internal bonding regions are disposed along different lateral edges of at least one external bonding region of the plurality of external bonding regions. (Item 70) Item 69. The display system of item 68, wherein the plurality of inner bonding regions surround the plurality of outer bonding regions. (Item 71) Item 69. The display system of item 68, wherein each inner bonding region of the plurality of inner bonding regions corresponds to a unique outer bonding region of the plurality of outer bonding regions and is configured to selectively direct light. (Item 72) Item 69. The display system of item 68, wherein the light coupling region is configured to redirect incident light from the optical projection system through the waveguide along a propagation direction at an angle for total internal reflection, and further comprising a light dispersing structure configured to redirect a portion of the light to propagate along an axis intersecting the propagation direction. (Item 73) Item 73. The display system of item 72, wherein the light dispersing structure and the plurality of outcoupling regions are disposed on opposing major surfaces of the at least one waveguide. (Item 74) Item 69. The display system of item 68, wherein the external coupling regions define a grid pattern across the waveguide. (Item 75) the head mountable display comprises a plurality of waveguides forming a waveguide stack, each of the waveguides comprising a plurality of the inner coupling regions and the outer coupling regions; the incoupling region of each of the waveguides is laterally displaced, as viewed in a front plan view, when viewed from the direction of incoupling light incident on the incoupling region. Item 69. The display system of item 68. (Item 76) the outcoupling regions of the same waveguide are configured to output light with the same wavefront divergence; the outcoupling regions of the different waveguides are configured to output light with a different amount of wavefront divergence than the outcoupling regions of the at least one other waveguide; The different amounts of wavefront divergence correspond to different depth planes. Item 76. The display system of item 75. (Item 77) the incoupling region of each waveguide is configured to incoupling light in a range of wavelengths corresponding to the same primary color; the incoupling regions of some of the waveguides are configured to incoupling light in ranges of wavelengths corresponding to different primary colors from the incoupling regions of other waveguides; Item 76. The display system of item 75. (Item 78) Item 68. The display system of item 67, wherein the plurality of internal coupling regions comprise a diffraction grating. (Item 79) Item 79. The display system of item 78, wherein each of the plurality of internal coupling regions has a different grating pitch than at least one other internal coupling region of the waveguide. (Item 80) Item 79. The display system of item 78, wherein each of the plurality of internal coupling regions has a different lattice orientation in the plane of the waveguide than at least one other internal coupling region of the waveguide. (Item 81) Item 68. The display system of item 67, wherein each of the plurality of internal coupling regions has a different inclination relative to the plane of the waveguide than at least one other internal coupling region of the waveguide. (Item 82) Item 68. The display system of item 67, wherein the internal bonding regions are spaced apart from each other. (Item 83) Item 68. The display system of item 67, wherein each of the plurality of internal coupling regions is arranged to internally couple light and direct the light to propagate within the waveguide by total internal reflection along a different direction than at least one other internal coupling region of the waveguide. (Item 84) Item 68. The display system of item 67, wherein the light projection system comprises at least one light source and at least one movable light launcher configured to direct image light to individual ones of the internal bonding regions. (Item 85) The optical projection system comprises: at least one light source comprising an array of light emitters; at least one spatial light modulator configured to modulate light from the light source; a projection optical system mounted on a frame and configured to direct light from the spatial light modulator to the incoupling region; Equipped with The display system is configured to activate different light emitters to provide the virtual image content on different depth planes, the display system comprising: providing a relatively large distance between individual light emitters of the plurality of light emitters to provide the virtual image content on a relatively near depth plane; providing a relatively small distance between individual light emitters of the plurality of light emitters to provide the virtual image content on a relatively far depth surface; Item 68. The display system of item 67, configured to perform the following: (Item 86) Item 86. The display system of item 85, wherein each of the light emitters of the plurality of light emitters is configured to be activated sequentially at a different time, and wherein the display system is configured to synchronize activation of each light emitter with display of different parallaxically disparate intrapupillary images. (Item 87) Item 68. The display system of item 67, further comprising variable focus lens elements on opposing side edges of the waveguide. (Item 88) Item 68. The display system of item 67, wherein the optical projection system comprises a plurality of projectors, the projectors of the plurality of projectors being configured to provide image content for at most a subdivided portion of the FOV of the head mounted display. [Brief description of the drawings]

[0099] [Figure 1] FIG. 1 illustrates a user's view of an augmented reality (AR) scene through an AR device.

[0100] [Diagram 2] FIG. 2 illustrates a conventional display system for simulating a three-dimensional image for a user.

[0101] [Diagram 3] 3A-3C illustrate the relationship between the radius of curvature and the radius of focus.

[0102] [Figure 4A] Figure 4A illustrates a representation of the accommodation-vergence-divergence motor response of the human visual system.

[0103] [Figure 4B] FIG. 4B illustrates examples of different accommodation and convergence states of a pair of a user's eyes.

[0104] [Figure 4C] FIG. 4C illustrates an example of a top-down view representation of a user viewing content through a display system.

[0105] [Figure 4D] FIG. 4D illustrates another example of a top-down view representation of a user viewing content through a display system.

[0106] [Diagram 5] FIG. 5 illustrates aspects of an approach for simulating a three-dimensional image by modifying wavefront divergence.

[0107] [Figure 6] FIG. 6 illustrates an embodiment of a waveguide stack for outputting image information to a user.

[0108] [Figure 7] FIG. 7 illustrates an example of an output beam output by a waveguide.

[0109] [Figure 8] FIG. 8 illustrates an example of a stacked waveguide assembly where each depth plane contains an image formed using multiple different primary colors.

[0110] [Figure 9A] FIG. 9A illustrates a cross-sectional side view of an example of a set of stacked waveguides, each of which includes an internal coupling optical element.

[0111] [Figure 9B] FIG. 9B illustrates a perspective view of the multiple stacked waveguide embodiment of FIG. 9A.

[0112] [Figure 9C] FIG. 9C illustrates a top-down plan view of the multiple stacked waveguide embodiment of FIGS. 9A and 9B.

[0113] [Figure 9D] FIG. 9D illustrates an example of a wearable display system.

[0114] [Figure 10A] FIG. 10A illustrates an exemplary outcoupling element that outcouples light from a waveguide towards a user's eye.

[0115] [Figure 10B] FIG. 10B illustrates an example configuration of segmenting the example outer coupling element of FIG. 10A into different outer coupling regions.

[0116] [Figure 10C] FIG. 10C illustrates an example path of a light beam that may be coupled out of a waveguide of an example wearable display system.

[0117] [Figure 10D] FIG. 10D illustrates an exemplary primary ray of light that may be coupled out of a waveguide of an exemplary wearable display system.

[0118] [Figure 11A] FIG. 11A illustrates an exemplary outcoupling element having an array of light dispersing structures.

[0119] [Figure 11B] FIG. 11B illustrates an example segmented configuration of an example outer coupling element.

[0120] [Figure 11C] FIG. 11C illustrates an example cross-sectional side view of the waveguide of FIG. 11B.

[0121] [Figure 12A] FIG. 12A illustrates an example display system including an external coupling element having multiple segments.

[0122] [Figure 12B] FIG. 12B illustrates an exemplary arrangement of inner coupling elements along with an exemplary non-rectangular outer coupling element.

[0123] [Figure 13] FIG. 13 illustrates an example inner coupling element configuration surrounding an example outer coupling element.

[0124] [Figure 14A] FIG. 14A illustrates another example inner coupling element configuration in conjunction with an example outer coupling element.

[0125] [Figure 14B] FIG. 14B is an example of a cross-sectional side view of the waveguide of FIG. 14A.

[0126] [Figure 14C] FIG. 14C illustrates a cross-sectional side view of an example of a set of stacked waveguides, each of which includes an internal coupling optical element configuration.

[0127] [Figure 15] FIG. 15 illustrates a flow chart of an embodiment of a process for selection of an outcoupling region based on the direction of light relative to a user's eye.

[0128] [Figure 16]FIG. 16 illustrates a flow chart of an embodiment of a process for selection of an external binding region based on eye pose.

[0129] [Figure 17A] FIG. 17A illustrates diagrammatically an embodiment of an eye.

[0130] [Figure 17A-1] FIG. 17A-1 diagrammatically illustrates an exemplary coordinate system for determining eye posture.

[0131] [Figure 17B] FIG. 17B is a schematic diagram of a wearable system including an eye tracking system.

[0132] [Figure 17C] FIG. 17C is a block diagram of a wearable system that may include an eye tracking system.

[0133] [Figure 18] FIG. 18 illustrates a flow chart of an exemplary process for operating a display system having multiple internal bonding regions.

[0134] [Figure 19] FIG. 19 illustrates an example display with an array of internal bonding regions and a light injection system for directing light to selected regions.

[0135] [Figure 20A] 20A-20D illustrate an exemplary movable light launch system that includes a scanning fiber launcher. [Figure 20B] 20A-20D illustrate an exemplary movable light launch system that includes a scanning fiber launcher. [Figure 20C] 20A-20D illustrate an exemplary movable light launch system that includes a scanning fiber launcher. [Figure 20D] 20A-20D illustrate an exemplary movable light launch system that includes a scanning fiber launcher.

[0136] [Figure 21A] 21A-21B illustrate an exemplary movable light injection system that includes a scanning mirror. [Figure 21B] 21A-21B illustrate an exemplary movable light injection system that includes a scanning mirror.

[0137] [Figure 22] FIG. 22 illustrates an exemplary stationary light injection system including a spatial light modulator.

[0138] [Figure 23] FIG. 23 illustrates a top-down plan view of an optical module having multiple optical emitters.

[0139] [Figure 24] FIG. 24 illustrates a variable focus lens system.

[0140] [Figure 25A] FIG. 25A illustrates the pre-accommodation and post-accommodation states of the eye for a constant incident wavefront.

[0141] [Figure 25B] FIG. 25B illustrates the pre-accommodation and post-accommodation states of the eye for a piecewise approximation of one continuously incident wavefront.

[0142] [Figure 25C] FIG. 25C illustrates an example of a display system that includes a projection system for forming the diverging wavefront approximation of FIG. 25B.

[0143] [Figure 25D] FIG. 25D illustrates an example of a display system comprising an eye tracking system and a pupil relay combiner eyepiece with a pupil expander configured to produce a non-infinite depth plane. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0144] Detailed Description An AR and / or VR system may display virtual content to a user or viewer. For example, the content may be displayed on a head-mounted display that projects image information to the user's eyes, e.g., as part of eyewear. In addition, if the system is an AR system, the display may also transmit light from the surrounding environment to the user's eyes, allowing a view of the surrounding environment. As used herein, it should be understood that a "head-mounted" or "head-mountable" display is a display that can be mounted on the viewer's or user's head. Such a display may be understood to form part of a display system.

[0145] In various augmented reality and virtual reality display systems, a waveguide may extend across an associated eye of a user. The waveguide may be configured to output image light with image information to form an image within the eye. For example, the light may be output using an external coupling element (which may be a grating) that redirects the light out of the waveguide toward the eye.

[0146] It should be understood that the eye may move relative to the waveguide. To ensure that the eye continues to receive the image light even when it moves, the waveguide may output image light with similar image information across the entire extension of the viewing area of ​​the waveguide. This allows the eye to receive the image light even when it moves and is aligned with the different areas of the waveguide. Some of the light outcoupled by the external coupling element may be usefully directed into the pupil of the eye where it will enter the eye and form an image, but other light outcoupled by the external coupling element may not be incident on the pupil of the eye and therefore does not contribute to the image seen by the eye. Thus, although energy is used to generate all of the output light, only a small portion of that light reaches the eye and forms an image. Undesirably, the light that does not enter the pupil of the eye and the energy used to generate that light may be considered "wasted" in a sense, since it is not perceived by the viewer.

[0147] Advantageously, in some implementations, the display system disclosed herein allows light to be utilized in a highly efficient manner. Rather than outputting light across the entire viewing area of ​​the waveguide, light is selectively output from regions of the waveguide that are aligned with the eye, thereby increasing the percentage of output light that enters the eye's pupil. Preferably, these regions occupy an area that is less than the entire viewing area of ​​the waveguide, and in some implementations, greater than the area of ​​the average eye pupil, which may result in the viewing area being divided into two or more, three or more, four or more, or nine or more distinct light outcoupling regions. Thus, light is not wasted by being output across the entire viewing area, while the output area is large enough to provide the desired field of view and provide some tolerance for eye movement.

[0148] In some implementations, an external coupling region may have a unique associated or correlated internal coupling region. It should be understood that the internal coupling region receives image light (such as light modulated by a spatial light modulator) and internally couples this image light in a waveguide so that it propagates toward and is incident on an external coupling region, where the light is externally coupled to propagate toward the user's eye. In some implementations, light dispersion features may also be utilized to distribute light from the internal coupling region along an axis and across a desired external coupling region. Because the internal coupling region selectively steers light toward an associated or correlated external coupling region, the external coupling region for outputting light may be selected by directing light into the associated internal coupling region or regions. Advantageously, in addition to energy efficiency, flexibility in placement of the internal coupling regions may be provided by associating specific internal coupling regions with specific external coupling regions. For example, the internal coupling regions may be distributed in a line across the waveguide and / or around the circumference of the waveguide, which may have the advantage of providing a thinner form factor or a wider range of waveguide shapes than internal coupling regions that must be localized within the same portion of the waveguide.

[0149] It should be understood that the display system may include a light projection system configured to selectively direct light into one or more desired in-coupling regions. In some examples, the light projection system may include a projector or multiple projectors, and / or the projector may function as a light source in some implementations. The light projection system may also be referred to as a light injection system because it inputs light into the in-coupling region. The light projection system may include a single projection device or multiple projection devices (such as light projectors). In some implementations, the field of view (FOV) of the display system may be subdivided into multiple portions, and each of the light projection devices may be configured to project image content for an associated portion of the full FOV. Thus, in some implementations, each projector provides image content for less than or equal to the subdivided portion of the field of view of the display system. It should be understood that to provide acceptable image quality, the optical system and associated systems for forming the full FOV may be complex and large in size, especially when the projection system collimates the light for input into the waveguide. On the other hand, the optics and associated systems for projectors to form only a portion of the FOV may be simpler, and in some implementations the total size of a light projection system having multiple light projectors (each providing image content for a portion of the full field of view) may be smaller than the size of a single light projection system providing image content for the full FOV. Thus, advantageously, the use of multiple light projectors may facilitate a smaller form factor than a system with a single light projector for the full field of view.

[0150] In some implementations, the optical projection system may include a mechanically actuated structure to physically adjust the direction of the output image light toward the desired in-coupling region. For example, the optical projection system may include one or more switchable mirrors, which may be rotated, for example, to direct light from one or more light sources into the desired in-coupling region. In some other implementations, the optical projection system may include one or more scanning fibers, which are configured to scan across the in-coupling region and output light when an output end of the scanning fiber is aligned with a location corresponding to the desired in-coupling region.

[0151] In some other implementations, the light projection system may electrically switch the light output onto the different incoupling regions without mechanical actuation. For example, the light projection system may include a plurality of individually activated light sources arranged to provide unique light paths to respective ones of the incoupling regions. As a result, activation of the appropriate light sources may be utilized to direct light into the desired incoupling region. In some implementations, a spatial light modulator may be provided in the light path between the light sources and the incoupling regions to encode the light from the light sources with image information to form an image.

[0152] In some implementations, an appropriate out-coupling region for outputting light may be selected based on a determination of the orientation of the eye, e.g., the orientation of the pupil of the eye. For example, the display system may include an inward-facing camera that images the eye and determines its orientation. In some implementations, the line of sight of the eye may be extrapolated to determine an intersection of the line of sight and the out-coupling region. The intersecting light out-coupling region may be understood as a desired region for receiving image light for output to the eye.

[0153] In some implementations, the location of a virtual object to be displayed in conjunction with eye posture may be utilized to select an outer binding region to receive image light for output. For example, a virtual object may be understood to be located within a particular portion of a user's field of view that overlaps with a particular outer binding region. As a result, that outer binding region may be designated to receive image light. In some implementations, this outer binding region may also intersect with the line of sight of the eye, especially if the virtual object is an object that is expected to attract the user's attention (e.g., if the virtual object exhibits movement and / or temporal changes in visual properties such as changes in color, size, brightness, etc.).

[0154] Advantageously, in some implementations, the display system may provide a three-dimensional presentation of a virtual object with a high degree of viewing comfort. It should be appreciated that the left and right eyes of a user may be presented with different views of a virtual object to provide vergence cues and provide an impression of depth through stereoscopic vision. In addition, the display system may be configured to output light with different levels of wavefront divergence to induce an appropriate accommodation response for a desired depth. As a result, accommodation-vergence matching may be achieved, which may provide a comfortable and realistic viewing experience.

[0155] In some implementations, different levels of wavefront divergence may be achieved using multiple waveguides forming a stack of waveguides. The outer coupling region of each waveguide may include an outer coupling feature (e.g., a diffraction grating) configured to outcouple light with a particular amount of wavefront divergence. Thus, a desired amount of wavefront divergence may be selected by directing image light into an inner coupling region of a waveguide having an outer coupling region with an outer coupling feature configured to output light with a desired amount of wavefront divergence. In some implementations, the inner coupling regions for different waveguides may be displaced laterally as seen in a top-down plan view. Thus, different waveguides may be selected by directing light into different inner coupling regions. For example, a particular inner coupling region may be associated with a particular waveguide and also with a particular outer coupling region within that waveguide.

[0156] In some implementations, in addition to or as an alternative to multiple waveguides that output light with different amounts of wavefront divergence, one or more variable focus lens elements may be provided to modify the wavefront divergence of the light propagating from the waveguides to the eye. In some implementations, the variable focus lens elements may alternatively or additionally be used to provide refractive error correction for the light propagating towards the eye.

[0157] In some other implementations, the light projection system may include an array of discrete light sources that direct light from different angles through the projection optics to provide parallaxically dissimilar intra-pupillary images to approximate different amounts of wavefront divergence. In some implementations, a selectable separation between the discrete light sources may be utilized to modulate the wavefront divergence. For example, a relatively large distance between the individual light sources may provide a wavefront divergence that corresponds to a relatively near depth plane, while a relatively small distance between the individual light sources may provide a wavefront divergence that corresponds to a relatively far depth plane. Image light for the parallaxically dissimilar intra-pupillary images may be directed to an appropriate incoupling region as described herein. For example, a mechanically actuated structure such as a scanning mirror or a scanning fiber may be utilized to direct image light for the parallaxically dissimilar intra-pupillary images to an appropriate incoupling region.

[0158] Implementations of the present technology may provide various advantages. For example, implementations disclosed herein may advantageously improve display system efficiency by increasing the percentage of light produced by a light projection system that is used to form an image perceived by a user, while reducing the percentage of light that falls on other parts of the user's eye or face, or that does not otherwise contribute to the image perceived by the user. By selectively out-coupling light toward the pupil, such systems may reduce the amount of light energy generated by a light projection system or other display light source to produce an image of a given brightness at the user's eye. Furthermore, image brightness may be improved because a greater percentage of the generated light is directed into the eye. In addition, less energy may be directed to light generation for a desired brightness, thereby allowing energy usage to be redistributed for other uses, such as for computational processes, which may have advantages in image rendering, reduced latency, etc.

[0159] It should be noted that the internal coupling elements may be referred to herein as input coupling elements, internal coupling gratings (or ICGs), diffractive internal coupling elements, or the like. Similarly, the external coupling elements may be referred to herein as output coupling elements, diffractive external coupling elements, or the like.

[0160] Reference is now made to the drawings, in which like reference numbers refer to like parts throughout. Unless otherwise indicated, the drawings are schematic and are not necessarily drawn to scale. Exemplary Display Systems

[0161] FIG. 2 illustrates a conventional display system for simulating a three-dimensional image for a user. It should be understood that when a user's eyes are spaced apart and viewing a real object in space, each eye may have a slightly different view of the object and form an image of the object at a different location on each eye's retina. This may be referred to as binocular disparity and may be exploited by the human visual system to provide a perception of depth. Conventional display systems simulate binocular disparity by presenting two distinctly different images 190, 200 with slightly different views of the same virtual object, one for each eye 210, 220, corresponding to the view of the virtual object as it would appear by each eye as if the virtual object were a real object at a desired depth. These images provide binocular cues that the user's visual system may interpret to derive a perception of depth.

[0162] Continuing with reference to FIG. 2, the images 190, 200 are spaced from the eyes 210, 220 by a distance 230 on the z-axis, which is parallel to the optical axis of the viewer when that eye is fixating on an object at optical infinity directly in front of the viewer. The images 190, 200 are flat and at a fixed distance from the eyes 210, 220. Based on slightly different views of the virtual object in the images presented to the eyes 210, 220, respectively, the eyes may necessarily rotate such that the image of the object falls on a corresponding point on the eye's respective retina to maintain single binocular vision. This rotation may cause the line of sight of each of the eyes 210, 220 to converge on a point in space where the virtual object is perceived to reside. As a result, providing three-dimensional images traditionally involves manipulating the convergence and divergence movements of the user's eyes 210, 220 to provide binocular cues that the human visual system interprets to provide the perception of depth.

[0163] However, creating a realistic and comfortable perception of depth is difficult. It should be understood that light from an object at different distances from the eye has a wavefront with different amounts of divergence. Figures 3A-3C illustrate the relationship between distance and divergence of light rays. The distance between the object and the eye 210 is represented in the order of decreasing distances R1, R2, and R3. As shown in Figures 3A-3C, the light rays become more divergent as the distance to the object decreases. Conversely, as the distance increases, the light rays become more collimated. In other words, the light field generated by a point (an object or part of an object) may be said to have a spherical wavefront curvature that is a function of the distance the point is away from the user's eye. The curvature increases with decreasing distance between the object and the eye 210. Although only a single eye 210 is illustrated in Figures 3A-3C and various other figures herein for clarity of illustration, the discussion regarding the eye 210 may apply to both eyes 210 and 220 of a viewer.

[0164] 3A-3C, light from an object that a viewer's eye is fixating on may have different wavefront divergences. Due to the different wavefront divergences, the light may be focused differently by the eye's lens, which in turn may require the lens to assume a different shape and form a focused image on the eye's retina. If a focused image is not formed on the retina, the resulting retinal blur acts as an accommodative cue, causing the shape of the eye's lens to change until a focused image is formed on the retina. For example, an accommodative cue may induce relaxation or contraction of the ciliary muscle surrounding the eye's lens, thereby modulating the force applied to the suspensory ligament that holds the lens, thus changing the shape of the eye's lens, thereby forming a focused image of the fixated object on the eye's retina (e.g., the fovea) until retinal blur of the fixated object is eliminated or minimized. The process by which the eye lens changes shape may be referred to as accommodation, and the shape of the eye lens required to form a focused image of a fixated object on the eye's retina (e.g., the fovea) may be referred to as the state of accommodation.

[0165] Referring now to FIG. 4A, a representation of the accommodation-vergence response of the human visual system is illustrated. A movement of the eye to fixate an object causes the eye to receive light from the object, which forms an image on each of the eye's retinas. The presence of retinal blur in the image formed on the retina may provide a cue for accommodation, and the relative location of the image on the retina may provide a cue for vergence. A cue for accommodation causes accommodation, resulting in the eye adopting a particular accommodation state in which the eye's lens forms a focused image of the object on the eye's retina (e.g., the fovea). On the other hand, a cue for vergence causes a vergence movement (eye rotation) such that the image formed on each retina of each eye is at a corresponding retinal point that maintains single binocular vision. In these positions, the eyes may be said to adopt a particular vergence state. Continuing with reference to FIG. 4A, accommodation can be understood to be the process by which the eye achieves a particular accommodation state, and convergence can be understood to be the process by which the eye achieves a particular convergence state. As shown in FIG. 4A, the accommodation and convergence state of the eye can change when the user fixates a different object. For example, the accommodated state can change when the user fixates a new object at a different depth on the z-axis.

[0166] Without being limited by theory, it is believed that a viewer of an object may perceive the object as being "three-dimensional" due to a combination of vergence-divergence and accommodation. As described above, vergence-divergence movements of the two eyes relative to one another (e.g., rotation of the eyes such that the pupils move toward or away from one another, converging the gaze of the eyes to fixate on an object) are closely linked to accommodation of the eye's lenses. Under normal conditions, changing the shape of the eye's lenses and shifting focus from one object to another at a different distance will automatically produce a matching change in vergence to the same distance, a relationship known as the "accommodation-vergence-divergence reflex." Similarly, a change in vergence will induce a matching change in lens shape under normal conditions.

[0167] 4B, an example of different accommodation and convergence-divergence states of the eyes is illustrated. Paired eye 222a fixates an object at optical infinity, while paired eye 222b fixates an object 221 at less than optical infinity. Notably, the convergence-divergence states of each pair of eyes are different, paired eye 222a points straight ahead, while paired eye 222 converges on object 221. The accommodation states of the eyes forming each pair of eyes 222a and 222b are also different, as represented by the different shapes of the lenses 210a, 220a.

[0168] Unfortunately, many users of conventional "3-D" display systems may find such conventional systems uncomfortable or may not perceive any depth sensation due to a mismatch between accommodation and vergence states in these displays. As described above, many stereoscopic or "3-D" display systems display a scene by providing a slightly different image to each eye. Such systems are uncomfortable for many viewers because, among other things, they simply provide different presentations of a scene, causing changes in the vergence states of the eyes, but without a corresponding change in the accommodation states of those eyes. Rather, images are presented by the display at a fixed distance from the eyes, such that the eyes view all image information in a single accommodation state. Such an arrangement counters the "accommodation-vergence-divergence reflex" by causing changes in vergence states without a matching change in accommodation state. This mismatch is believed to cause viewer discomfort. By providing better matching between accommodation and convergence-divergence movements, display systems may form a more realistic and comfortable simulation of three-dimensional images.

[0169] Without being limited by theory, it is believed that the human eye is typically capable of interpreting a finite number of depth planes to provide depth perception. As a result, a highly realistic simulation of perceived depth may be achieved by providing the eye with different presentations of images corresponding to each of these limited number of depth planes. In some implementations, the different presentations may provide both vergence cues and matching cues for accommodation, thereby providing physiologically correct accommodation-vergence divergence matching.

[0170] 4B, two depth planes 240 are illustrated, corresponding to different distances in space from the eyes 210, 220. For a given depth plane 240, vergence-divergence cues may be provided by displaying appropriately different perspective images for each eye 210, 220. In addition, for a given depth plane 240, the light forming the image provided to each eye 210, 220 may have a wavefront divergence corresponding to the light field generated by a point at the distance of that depth plane 240.

[0171] In the illustrated implementation, the distance along the z-axis of the depth plane 240 containing the point 221 is 1 m. As used herein, the distance or depth along the z-axis may be measured with the zero point located at the exit pupil of the user's eye. Thus, the depth plane 240 located at a depth of 1 m corresponds to a distance of 1 m away from the exit pupil of the user's eye on the optical axis of those eyes with the eyes pointed towards optical infinity. As an approximation, the depth or distance along the z-axis may be measured from the display (e.g., the surface of the waveguide) in front of the user's eye and a value for the distance between the device and the exit pupil of the user's eye may be added. That value may be called the pupil distance and may correspond to the distance between the exit pupil of the user's eye and the display worn by the user in front of the eye. In practice, the value for the pupil distance may be a normalized value that is generally used for all viewers. For example, the pupil distance may be assumed to be 20 mm and the depth plane at a depth of 1 m may be at a distance of 980 mm in front of the display.

[0172] 4C and 4D, examples of matched accommodation-vergence-divergence distances and mismatched accommodation-vergence-divergence distances are illustrated, respectively. As illustrated in FIG. 4C, the display system may provide an image of a virtual object to each eye 210, 220. The image may cause the eyes 210, 220 to assume a convergence-divergence state in which the eyes converge on point 15 on the depth plane 240. In addition, the image may be formed by light having a wavefront curvature corresponding to a real object in that depth plane 240. As a result, the eyes 210, 220 assume an accommodation state in which the image is focused on the retinas of those eyes. Thus, the user may perceive the virtual object as being at point 15 on the depth plane 240.

[0173] It should be appreciated that each of the accommodation and convergence states of the eyes 210, 220 is associated with a particular distance on the z-axis. For example, an object at a particular distance from the eyes 210, 220 will cause those eyes to assume a particular accommodation state based on the distance of the object. The distance associated with a particular accommodation state is referred to as the accommodation distance A. d Similarly, a particular convergence-divergence distance V associated with the eyes in a particular convergence-divergence state or position relative to one another may be referred to as d If the accommodation distance and the vergence distance match, the relationship between accommodation and vergence can be said to be physiologically correct. This is considered to be the most comfortable scenario for the viewer.

[0174] However, in a stereoscopic display, the accommodation distance and the convergence distance may not always match. For example, as illustrated in FIG. 4D, the images displayed to the eyes 210, 220 may be displayed with a wavefront divergence corresponding to the depth plane 240, and the eyes 210, 220 may be in a particular accommodation state in which the points 15a, 15b on that depth plane are in focus. However, the images displayed to the eyes 210, 220 may provide a convergence cue that causes the eyes 210, 220 to converge on a point 15 that is not located on the depth plane 240. As a result, in some implementations, the accommodation distance corresponds to the distance from the exit pupils of the eyes 210, 220 to the depth plane 240, while the convergence distance corresponds to a larger distance from the exit pupils of the eyes 210, 220 to the point 15. The accommodation distance is different from the convergence distance. As a result, there is an accommodation-vergence-divergence mismatch. Such a mismatch may be considered undesirable and may cause discomfort to the user. The mismatch may be related to distance (e.g., V d -A d ) and can be characterized in terms of diopters.

[0175] It should be appreciated that in some implementations, a reference point other than the exit pupil of the eye 210, 220 may be utilized to determine the distance for determining the accommodation-vergence-divergence mismatch, so long as the same reference point is utilized for the accommodation distance and the vergence-divergence distance. For example, the distance may be measured in a depth plane from the cornea, in a depth plane from the retina, in a depth plane from the eyepiece (e.g., a waveguide in a display device), etc.

[0176] Without being limited by theory, it is believed that a user may still perceive an accommodation-vergence-divergence mismatch of up to about 0.25 diopters, up to about 0.33 diopters, and up to about 0.5 diopters as physiologically correct without the mismatch itself causing significant discomfort. In some implementations, a display system disclosed herein (e.g., display system 250, FIG. 6) presents a viewer with an accommodation-vergence-divergence mismatch of about 0.5 diopters or less. In some other implementations, the accommodation-vergence-divergence mismatch of the image provided by the display system is about 0.33 diopters or less. In still other implementations, the accommodation-vergence-divergence mismatch of the image provided by the display system is about 0.25 diopters or less, including about 0.1 diopters or less.

[0177] FIG. 5 illustrates aspects of an approach for simulating a three-dimensional image by modifying wavefront divergence. The display system includes a waveguide 270 configured to receive light 770 encoded with image information and output the light to a user's eye 210. The waveguide 270 may output light 650 with a defined amount of wavefront divergence that corresponds to the wavefront divergence of a light field generated by a point on a desired depth plane 240. In some implementations, the same amount of wavefront divergence is provided for all objects presented on that depth plane. In addition, the user's other eye will be illustrated as being provided with image information from a similar waveguide.

[0178] In some implementations, a single waveguide may be configured to output light with a set wavefront divergence corresponding to a single or limited number of depth planes, and / or the waveguide may be configured to output light of a limited range of wavelengths. As a result, in some implementations, multiple or stacked waveguides may be utilized to provide different wavefront divergence for different depth planes and / or output light of different ranges of wavelengths. As used herein, it should be understood that a depth plane may be flat or may follow the contour of a curved surface.

[0179] 6 illustrates an example of a waveguide stack for outputting image information to a user. The display system 250 includes a stack of waveguides or a stacked waveguide assembly 260 that can be utilized to provide a three-dimensional perception to the eye / brain using multiple waveguides 270, 280, 290, 300, 310. It should be understood that the display system 250 may be considered a light field display in some implementations. In addition, the waveguide assembly 260 may also be referred to as an eyepiece.

[0180] In some implementations, the display system 250 may be configured to provide a substantially continuous cue for convergence and multiple discrete cues for accommodation. The cues for convergence may be provided by displaying different images to each of the user's eyes, and the cues for accommodation may be provided by outputting light forming images with selectable discrete amounts of wavefront divergence. In other words, the display system 250 may be configured to output light with variable levels of wavefront divergence. In some implementations, each discrete level of wavefront divergence corresponds to a particular depth plane and may be provided by a particular one of the waveguides 270, 280, 290, 300, 310.

[0181] Continuing with reference to FIG. 6, the waveguide assembly 260 may also include a number of features 320, 330, 340, 350 between the waveguides. In some implementations, the features 320, 330, 340, 350 may be one or more lenses. The waveguides 270, 280, 290, 300, 310 and / or the number of lenses 320, 330, 340, 350 may be configured to transmit image information to the eye with various levels of wavefront curvature or ray divergence. Each waveguide level may be associated with a particular depth plane and may be configured to output image information corresponding to that depth plane. The image input devices 360, 370, 380, 390, 400 may act as light sources for the waveguides and may be utilized to input image information into the waveguides 270, 280, 290, 300, 310, each of which may be configured to distribute incident light across each individual waveguide for output towards the eye 210, as described herein. Light exits output surfaces 410, 420, 430, 440, 450 of the image input devices 360, 370, 380, 390, 400 and is input into corresponding input surfaces 460, 470, 480, 490, 500 of the waveguides 270, 280, 290, 300, 310. In some implementations, each of the input surfaces 460, 470, 480, 490, 500 may be an edge of the corresponding waveguide or a portion of a major surface of the corresponding waveguide (i.e., one of the waveguide surfaces that directly faces the world 510 or the viewer's eye 210). In some implementations, a single beam of light (e.g., a collimated beam) may be launched into each waveguide, outputting a total field of cloned collimated beams that are directed toward the eye 210 at a particular angle (and divergence) corresponding to the depth plane associated with the particular waveguide. In some implementations, a single one of the image launch devices 360, 370, 380, 390, 400 may be associated with and launch light into multiple (e.g., three) waveguides 270, 280, 290, 300, 310.

[0182] In some implementations, each of the image input devices 360, 370, 380, 390, 400 is a discrete display that generates image information for input into a corresponding waveguide 270, 280, 290, 300, 310. In some other implementations, the image input devices 360, 370, 380, 390, 400 are the output of a single multiplexed display that may, for example, send image information via one or more optical conduits (such as fiber optic cables) to each of the image input devices 360, 370, 380, 390, 400. It should be understood that the image information provided by the image input devices 360, 370, 380, 390, 400 may include light of different wavelengths or colors (e.g., different primary colors as discussed herein).

[0183] In some implementations, the light injected into the waveguides 270, 280, 290, 300, 310 is encoded with image information and provided by the optical projection system 1010, as discussed further herein. In some implementations, the optical projection system 1010 may comprise one or more emitting pixel arrays. It should be understood that each emitting pixel array may comprise a plurality of light-emitting pixels, which are configured to emit light of variable intensity and color. It should be understood that the image injection devices 360, 370, 380, 390, 400 are illustrated diagrammatically, and in some implementations, these image injection devices may represent different light paths and locations within a common projection system that are configured to output light into associated ones of the waveguides 270, 280, 290, 300, 310. In some implementations, the waveguides of the waveguide assembly 260 may act as ideal lenses, relaying the light injected into the waveguides to the user's eye. In this concept, the object may be a pixel array of the light projection device 1010 and the image may be an image on a depth plane.

[0184] The controller 560 controls the operation of one or more of the stacked waveguide assemblies 260, including the operation of the image input devices 360, 370, 380, 390, 400 and the optical projection system 1010. In some implementations, the controller 560 is part of the local data processing module 140. The controller 560 includes programming (e.g., instructions in a non-transient medium) that coordinates the timing and provision of image information to the waveguides 270, 280, 290, 300, 310, for example, according to any of the various schemes disclosed herein. In some implementations, the controller may be a single integrated device or a distributed system connected by wired or wireless communication channels. The controller 560 may be part of the processing module 140 or 150 (FIG. 9D) in some implementations.

[0185] Continuing with reference to FIG. 6, the waveguides 270, 280, 290, 300, 310 may be configured to propagate light within each individual waveguide by total internal reflection (TIR). Each of the waveguides 270, 280, 290, 300, 310 may be planar or have another shape (e.g., curved) with major top and bottom surfaces and edges extending between the major top and bottom surfaces. In the illustrated configuration, each of the waveguides 270, 280, 290, 300, 310 may include an out-coupling optical element 570, 580, 590, 600, 610 configured to extract light from the waveguide by redirecting light propagating within each individual waveguide out of the waveguide and outputting image information to the eye 210. The extracted light may also be referred to as out-coupled light, and the out-coupling optical element may also be referred to as a light extraction optical element. The extracted beam of light may be output by the waveguide at a location where the light propagating within the waveguide strikes the light extraction optical element. The outcoupling optical element 570, 580, 590, 600, 610 may be a grating, for example, including diffractive optical features as further discussed herein. Although shown disposed on the bottom major surface of the waveguide 270, 280, 290, 300, 310 for ease of explanation and clarity of drawing, in some implementations the outcoupling optical element 570, 580, 590, 600, 610 may be disposed on the top and / or bottom major surfaces and / or directly within the volume of the waveguide 270, 280, 290, 300, 310, as further discussed herein. In some implementations, the outcoupling optical elements 570, 580, 590, 600, 610 may be formed within a layer of material that is attached to a transparent substrate and forms the waveguide 270, 280, 290, 300, 310. In some other implementations, the waveguide 270, 280, 290, 300, 310 may be a monolithic piece of material and the outcoupling optical elements 570, 580, 590, 600, 610 may be formed on and / or within that piece of material.

[0186] With continued reference to FIG. 6, as discussed herein, each waveguide 270, 280, 290, 300, 310 is configured to output light and form an image corresponding to a particular depth plane. For example, the waveguide 270 closest to the eye may be configured to deliver collimated light (injected into such waveguide 270) to the eye 210. The collimated light may represent an optical infinity focal plane. The next upper waveguide 280 may be configured to send collimated light that passes through a first lens 350 (e.g., a negative lens) before it can reach the eye 210. Such first lens 350 may be configured to generate a slight convex wavefront curvature such that the eye / brain interprets the light originating from the next upper waveguide 280 as originating from a first focal plane closer inward from optical infinity toward the eye 210. Similarly, the third upper waveguide 290 passes its output light through both the first lens 350 and the second lens 340 before reaching the eye 210. The combined refractive powers of the first lens 350 and the second lens 340 may be configured to produce another incremental amount of wavefront curvature such that the eye / brain interprets the light emerging from the third waveguide 290 as originating from a second focal plane that is closer inward from optical infinity towards the person than was the light from the next upper waveguide 280.

[0187] The other waveguide layers 300, 310 and lenses 330, 320 are similarly configured, with the highest waveguide 310 in the stack sending its output through all of the lenses between it and the eye for an aggregate focal power that represents the focal plane closest to the person. To compensate the stack of lenses 320, 330, 340, 350 when viewing / interpreting light originating from the world 510 on the other side of the stacked waveguide assembly 260, a compensating lens layer 620 may be placed on top of the stack to compensate for the aggregate power of the lens stacks 320, 330, 340, 350 below. Such a configuration provides as many perceived focal planes as there are waveguide / lens pairs available. Both the outcoupling optical elements of the waveguides and the focusing sides of the lenses may be static (i.e., not dynamic or electroactive). In some alternative implementations, one or both may be dynamic using electroactive features.

[0188] In some implementations, two or more of the waveguides 270, 280, 290, 300, 310 may have the same associated depth plane. For example, multiple waveguides 270, 280, 290, 300, 310 may be configured to output images set at the same depth plane, or multiple subsets of the waveguides 270, 280, 290, 300, 310 may be configured to output images set at the same depth planes, with one set per depth plane. This may provide the advantage of forming tiled images to provide an extended field of view at those depth planes.

[0189] Continuing with reference to FIG. 6, the outcoupling optical elements 570, 580, 590, 600, 610 may be configured to redirect light from its respective waveguide and output the light with an appropriate amount of divergence or collimation for a particular depth plane associated with the waveguide. As a result, waveguides with different associated depth planes may have different configurations of outcoupling optical elements 570, 580, 590, 600, 610 that output light with different amounts of divergence depending on the associated depth plane. In some implementations, the light extraction optical elements 570, 580, 590, 600, 610 may be solid or surface features that may be configured to output light at specific angles. For example, the light extraction optical elements 570, 580, 590, 600, 610 may be solid holograms, surface holograms, and / or diffraction gratings. In some implementations, the features 320, 330, 340, 350 may not be lenses. Rather, they may simply be spacers (e.g., cladding layers and / or structures to form an air gap).

[0190] In some implementations, the outcoupling optical elements 570, 580, 590, 600, 610 are diffractive features or "diffractive optical elements" (also referred to herein as "DOEs") that form a diffraction pattern. Preferably, the DOEs have a low enough diffraction efficiency so that only a portion of the light in the beam is deflected towards the eye 210 at each intersection of the DOE, while the remainder continues to travel through the waveguide via TIR. The light carrying the image information is thus split into several related exit beams that exit the waveguide at various locations, resulting in a very uniform pattern of exit emission towards the eye 210 for this particular collimated beam bouncing within the waveguide.

[0191] In some implementations, one or more DOEs may be switchable between an "on" state in which they actively diffract and an "off" state in which they do not significantly diffract. For example, a switchable DOE may comprise a layer of polymer dispersed liquid crystal in which microdroplets comprise a diffractive pattern in a host medium, and the refractive index of the microdroplets may be switched to substantially match the refractive index of the host material (in which case the pattern does not significantly diffract incident light), or the microdroplets may be switched to a refractive index that does not match that of the host medium (in which case the pattern actively diffracts incident light).

[0192] In some implementations, a camera assembly 630 (e.g., a digital camera, including visible light and infrared light cameras) may be provided to capture images of the eye 210 and / or tissue surrounding the eye 210, for example, to detect user input and / or monitor a physiological condition of the user. As used herein, a camera may be any image capture device. In some implementations, the camera assembly 630 may include an image capture device and a light source that projects light (e.g., infrared light) onto the eye, which may then be reflected by the eye and detected by the image capture device. In some implementations, the camera assembly 630 may be mounted to the frame 80 (FIG. 9D) and may be in electrical communication with the processing modules 140 and / or 150, which may process image information from the camera assembly 630. In some implementations, one camera assembly 630 may be utilized per eye to monitor each eye separately.

[0193] 7, an example of an output beam output by a waveguide is shown. Although one waveguide is shown, it should be understood that other waveguides in the waveguide assembly 260 (FIG. 6) may function similarly and that the waveguide assembly 260 includes multiple waveguides. Light 640 is launched into the waveguide 270 at the input surface 460 of the waveguide 270 and propagates within the waveguide 270 by TIR. At the point where the light 640 impinges on the DOE 570, a portion of the light exits the waveguide as an output beam 650. The output beam 650 is shown as approximately parallel, but may be redirected to propagate to the eye 210 at an angle (e.g., forming a diverging output beam) as discussed herein and depending on the depth plane associated with the waveguide 270. It should be understood that a nearly collimated exit beam may refer to a waveguide with outcoupling optics that outcouples light to form an image that appears to be set at a depth plane at a large distance (e.g., optical infinity) from the eye 210. Other waveguides or other sets of outcoupling optics may output a more divergent exit beam pattern, which would require the eye 210 to accommodate to a closer distance and focus on the retina, and would be interpreted by the brain as light from a distance closer to the eye 210 than optical infinity.

[0194] In some implementations, a full color image may be formed at each depth plane by overlaying an image on each of the primary colors, for example, three or more primary colors. FIG. 8 illustrates an example of a stacked waveguide assembly in which each depth plane includes an image formed using multiple different primary colors. The illustrated implementation shows depth planes 240a-240f, but more or less depths are also contemplated. Each depth plane may have three or more primary color images associated with it, including a first image of a first color G, a second image of a second color R, and a third image of a third color B. The different depth planes are illustrated by different numbers for diopters (dpt) following the letters G, R, and B. By way of example only, the numbers following each of these letters indicate the diopters (1 / m), i.e., the inverse distance of the depth plane from the viewer, and each box in the diagram represents an individual primary color image. In some implementations, the exact location of the depth planes for different primaries may vary to account for differences in the eye's focusing of different wavelengths of light. For example, different primary images for a given depth plane may be placed on depth planes that correspond to different distances from the user. Such an arrangement may increase visual acuity and user comfort and / or reduce chromatic aberration. Without being limited by theory, it should be understood that not placing different primary images at the same physical focus may help to compensate for the natural longitudinal chromatic aberration (LCA) of the human eye, which may be important. For example, the eyepiece may help to compensate for the LCA of the eye by biasing the focus level of the primary images so that they are focused on the retina after being focused by the high LCA optics of the eye. In some implementations, the system may have a sparser set of depth planes for one primary (e.g., a 2x blue depth plane) and a denser set of depth planes for another primary (e.g., a 6x green depth plane). Advantageously, this approach can help reduce hardware cost and complexity while still providing proper depth information to the eye: for example, the eye prioritizes focusing of medium (e.g., "green") wavelengths over short and long wavelengths, and therefore may not require a uniform set of depth planes across all primary color images.For example, in some implementations, under the assumption that the eye will prioritize mid-wavelength light (e.g., for forming a green primary image) when perceiving a depth plane for a full-color image, a waveguide that outputs a primary image formed by short or long wavelength light (e.g., a blue or red primary image) may be utilized to form a full-color image on multiple depth planes, while a waveguide that outputs a primary image formed by mid-wavelength light (e.g., a green primary image) may be used to form a full-color image for only a single depth plane. Thus, there may be a one-to-one correspondence between the number of waveguides for mid-wavelength light and the total number of available depth planes, while the number of waveguides for another wavelength primary color (such as red and / or blue light) may be less than the total number of available depth planes.

[0195] In some implementations, the light of each primary color may be output by a single dedicated waveguide, such that each depth plane may have multiple waveguides associated with it. In such implementations, each box in the figure containing the letter G, R, or B may be understood to represent an individual waveguide, and three waveguides may be provided per depth plane, with three primary color images provided per depth plane. The waveguides associated with each depth plane are shown adjacent to each other in this drawing for ease of illustration, but it should be understood that in a physical device, the waveguides may all be arranged in a stack with one waveguide per level. In some other implementations, multiple primary colors may be output by the same waveguide, such that, for example, only a single waveguide may be provided per depth plane.

[0196] 8, in some implementations, G is green, R is red, and B is blue. In some other implementations, other colors associated with other wavelengths of light, including magenta and cyan, may be used in addition to or replace one or more of the red, green, or blue colors.

[0197] It should be understood that references throughout this disclosure to a given color of light are understood to encompass light of one or more wavelengths within the range of wavelengths of light that are perceived by a viewer as that given color. For example, red light may include one or more wavelengths of light within the range of about 620-780 nm, green light may include one or more wavelengths of light within the range of about 492-577 nm, and blue light may include one or more wavelengths of light within the range of about 435-493 nm.

[0198] In some implementations, the light projection system 1010 (FIG. 6) may be configured to emit light at one or more wavelengths outside the range of visual perception of a viewer, e.g., infrared and / or ultraviolet wavelengths. Additionally, the waveguide in-coupling, out-coupling, and other light redirecting structures of the display 250 may be configured to direct and emit this light from the display toward the user's eye 210, e.g., for imaging and / or user stimulation applications.

[0199] 9A, in some implementations, light impinging on a waveguide may need to be redirected to in-couple the light into the waveguide. An in-coupling optical element may be used to redirect and in-couple the light into its corresponding waveguide. FIG. 9A illustrates a cross-sectional side view of an example of a plurality or set 660 of stacked waveguides, each including an in-coupling optical element. Each of the waveguides may be configured to output light of one or more different wavelengths or one or more different wavelength ranges. The stack 660 may correspond to the stack 260 (FIG. 6), and the illustrated waveguides of the stack 660 may correspond to a portion of the plurality of waveguides 270, 280, 290, 300, 310, but it should be understood that light from one or more of the image input devices 360, 370, 380, 390, 400 is input into the waveguide from a position that requires the light to be redirected for in-coupling.

[0200] The illustrated set 660 of stacked waveguides includes waveguides 670, 680, and 690. Each waveguide includes an associated incoupling optical element (which may also be referred to as the light input area on the waveguide), for example, incoupling optical element 700 is disposed on a major surface (e.g., the top major surface) of waveguide 670, incoupling optical element 710 is disposed on a major surface (e.g., the top major surface) of waveguide 680, and incoupling optical element 720 is disposed on a major surface (e.g., the top major surface) of waveguide 690. In some implementations, one or more of the incoupling optical elements 700, 710, 720 may be disposed on the bottom major surface of the respective waveguides 670, 680, 690 (particularly, one or more of the incoupling optical elements are reflective polarizing optical elements). As shown, the internal coupling optical elements 700, 710, 720 may be disposed on the upper major surfaces of their respective waveguides 670, 680, 690 (or on top of the next lower waveguide), and in particular, the internal coupling optical elements are transmissive polarizing optical elements. In some implementations, the internal coupling optical elements 700, 710, 720 may be disposed within the body of the respective waveguides 670, 680, 690. In some implementations, as discussed herein, the internal coupling optical elements 700, 710, 720 are wavelength selective, such that they selectively redirect one or more wavelengths of light while transmitting other wavelengths of light. Although illustrated on one side or corner of the respective waveguides 670, 680, 690, it should be understood that the internal coupling optical elements 700, 710, 720 may be disposed within other areas of the respective waveguides 670, 680, 690 in some implementations. It should be understood that the incoupling optical elements 700, 710, 720 may be understood to be incoupling regions, with each incoupling element corresponding to an incoupling region. In some other implementations, each of the incoupling optical elements of each waveguide may be subdivided into multiple regions, as discussed herein.

[0201] As shown, the in-coupling optical elements 700, 710, 720 may be laterally offset from one another. In some implementations, each in-coupling optical element may be offset to receive light without that light passing through another in-coupling optical element. For example, each in-coupling optical element 700, 710, 720 may be configured to receive light from different image input devices 360, 370, 380, 390, and 400 as shown in FIG. 6 and may be separated (e.g., laterally spaced) from the other in-coupling optical elements 700, 710, 720 so as to not receive substantially any light from others of the in-coupling optical elements 700, 710, 720.

[0202] Each waveguide also includes an associated optically dispersive element, for example, optically dispersive element 730 is disposed on a major surface (e.g., a top major surface) of waveguide 670, optically dispersive element 740 is disposed on a major surface (e.g., a top major surface) of waveguide 680, and optically dispersive element 750 is disposed on a major surface (e.g., a top major surface) of waveguide 690. In some other implementations, optically dispersive elements 730, 740, 750 may be disposed on the bottom major surfaces of associated waveguides 670, 680, 690, respectively. In some other implementations, optically dispersive elements 730, 740, 750 may be disposed on both the top and bottom major surfaces of associated waveguides 670, 680, 690, respectively, or optically dispersive elements 730, 740, 750 may be disposed on different ones of the top and bottom major surfaces in different associated waveguides 670, 680, 690, respectively.

[0203] The waveguides 670, 680, 690 may be spaced apart and separated, for example, by gas, liquid, and / or solid layers of material. For example, as shown, layer 760a may separate the waveguides 670 and 680, and layer 760b may separate the waveguides 680 and 690. In some implementations, layers 760a and 760b are formed from a low index material (i.e., a material having a lower index of refraction than the material forming the immediately adjacent ones of the waveguides 670, 680, 690). Preferably, the index of refraction of the material forming layers 760a, 760b is 0.05 or greater, or 0.10 or less, than the index of refraction of the material forming the waveguides 670, 680, 690. Advantageously, the lower refractive index layers 760a, 760b may act as cladding layers to promote total internal reflection (TIR) ​​of light through the waveguides 670, 680, 690 (e.g., TIR between the top and bottom major surfaces of each waveguide). In some implementations, the layers 760a, 760b are formed from air. Although not shown, it should be understood that the top and bottom of the illustrated set of waveguides 660 may include immediate cladding layers.

[0204] Preferably, for ease of manufacturing and other considerations, the materials forming the waveguides 670, 680, 690 are similar or identical and the materials forming the layers 760a, 760b are similar or identical. In some implementations, the materials forming the waveguides 670, 680, 690 may differ between one or more of the waveguides and / or the materials forming the layers 760a, 760b may differ while still maintaining the various refractive index relationships described above.

[0205] 9A, light rays 770, 780, 790 are incident on the set of waveguides 660. It should be understood that light rays 770, 780, 790 may be injected into the waveguides 670, 680, 690 by one or more image injection devices 360, 370, 380, 390, 400 (FIG. 6).

[0206] In some implementations, the light beams 770, 780, 790 are intended for different waveguides (e.g., waveguides configured to output light with different amounts of wavefront divergence and / or configured to output light having different properties, such as different wavelengths or colors). Thus, in some implementations, the light beams 770, 780, 790 may have different wavelengths or different wavelength ranges that may correspond to different properties, e.g., different colors. Each of the internal coupling optical elements 700, 710, 720 deflects incident light such that the light propagates through a respective one of the waveguides 670, 680, 690 by TIR. In some implementations, each of the internal coupling optical elements 700, 710, 720 selectively deflects one or more particular wavelengths of light while transmitting other wavelengths to the underlying waveguide and associated internal coupling optical element.

[0207] For example, incoupling optical element 700 may be configured to deflect light beam 770 having a first wavelength or wavelength range while transmitting light beams 780 and 790 having different second and third wavelengths or wavelength ranges, respectively. The transmitted light beam 780 impinges on and is deflected by incoupling optical element 710, which is configured to deflect light of the second wavelength or wavelength range. Light beam 790 is deflected by incoupling optical element 720, which is configured to selectively deflect light of the third wavelength or wavelength range.

[0208] 9A, the deflected light rays 770, 780, 790 are deflected to propagate through the corresponding waveguides 670, 680, 690. That is, the incoupling optical element 700, 710, 720 of each waveguide deflects the light into its corresponding waveguide 670, 680, 690 and incouplings the light into its corresponding waveguide. The light rays 770, 780, 790 are deflected at an angle that causes the light to propagate through the respective waveguides 670, 680, 690 by TIR. The light rays 770, 780, 790 propagate through the respective waveguides 670, 680, 690 by TIR until they strike the corresponding optical dispersive element 730, 740, 750 of the waveguide.

[0209]

[0046] Referring now to Figure 9B, a perspective view of the multiple stacked waveguide embodiment of Figure 9A is illustrated. As described above, the in-coupled light rays 770, 780, 790 are deflected by the in-coupling optical elements 700, 710, 720, respectively, and then propagate by TIR within the waveguides 670, 680, 690, respectively. The light rays 770, 780, 790 then impinge on the optically dispersive elements 730, 740, 750, respectively. The optically dispersive elements 730, 740, 750 deflect the light rays 770, 780, 790 to propagate towards the out-coupling optical elements 800, 810, 820, respectively.

[0210] In some implementations, the optically dispersive elements 730, 740, 750 are orthogonal pupil expanders (OPEs). In some implementations, the OPEs deflect or disperse the light to the out-coupling optical elements 800, 810, 820, and in some implementations may also increase the beam or spot size of this light as it propagates to the out-coupling optical elements. In some implementations, the optically dispersive elements 730, 740, 750 may be omitted and the in-coupling optical elements 700, 710, 720 may be configured to deflect the light directly to the out-coupling optical elements 800, 810, 820. For example, referring to FIG. 9A, the optically dispersive elements 730, 740, 750 may be replaced with the out-coupling optical elements 800, 810, 820, respectively. In some implementations, the external coupling optical elements 800, 810, 820 are exit pupils (EPs) or exit pupil expanders (EPEs) that direct light to the viewer's eye 210 (FIG. 7). It should be understood that the OPEs may be configured to increase the dimensions of the eyebox in at least one axis, and the EPEs may increase the eyebox in an axis that intersects, e.g., orthogonal to, the axis of the OPE. For example, each OPE may be configured to redirect a portion of the light striking the OPE to the EPE of the same waveguide, while allowing the remaining portion of the light to continue propagating down the waveguide. In response to striking the OPE again, another portion of the remaining light is redirected to the EPE, and the remaining portion of that portion continues to propagate further down the waveguide, and so on. Similarly, in response to striking an EPE, a portion of the impinging light is directed out of the waveguide toward the user, and the remaining portion of that light continues to propagate through the waveguide until it again strikes an EP, at which point another portion of the impinging light is directed out of the waveguide, etc. As a result, a single beam of internally coupled light may be "replicated" each time a portion of that light is redirected by an OPE or EPE, thereby forming a cloned beam field of light, as shown in Figure 6. In some implementations, the OPE and / or EPE may be configured to modify the size of the beam of light.

[0211] Thus, referring to Figures 9A and 9B, in some implementations, a set of waveguides 660 includes, for each primary color, a waveguide 670, 680, 690, an in-coupling optical element 700, 710, 720, an optical dispersion element (e.g., OPE) 730, 740, 750, and an out-coupling optical element (e.g., EP) 800, 810, 820. The waveguides 670, 680, 690 may be stacked with an air gap / cladding layer between each one. The in-coupling optical element 700, 710, 720 redirects or deflects the incoming light into its waveguide (with different in-coupling optical elements receiving different wavelengths of light). The light then propagates at an angle that will result in TIR within the individual waveguides 670, 680, 690. In the illustrated embodiment, light ray 770 (e.g., blue light) is deflected by the first in-coupling optical element 700 in the manner described above, then continues to bounce back down the waveguide, interacting with the optically dispersive element (e.g., OPE) 730 and then the out-coupling optical element (e.g., EP) 800. Light rays 780 and 790 (e.g., green and red light, respectively) pass through the waveguide 670, where light ray 780 impinges on and is deflected by the in-coupling optical element 710. Light ray 780 will then proceed via TIR back down the waveguide 680, to its optically dispersive element (e.g., OPE) 740 and then the out-coupling optical element (e.g., EP) 810. Finally, light ray 790 (e.g., red light) passes through the waveguide 690 and impinges on the optically in-coupling optical element 720 of the waveguide 690. The light in-coupling optical element 720 deflects the light beam 790 such that it propagates by TIR to a light dispersive element (e.g., OPE) 750 and then by TIR to an out-coupling optical element (e.g., EP) 820. The out-coupling optical element 820 then finally out-couples the light beam 790 to a viewer, who also receives the out-coupled light from the other waveguides 670, 680.

[0212] FIG. 9C illustrates a top-down plan view of the multiple stacked waveguide embodiment of FIGS. 9A and 9B. As shown, the waveguides 670, 680, 690 may be vertically aligned with each waveguide's associated light dispersive element 730, 740, 750 and associated out-coupling optical elements 800, 810, 820. However, as discussed herein, the in-coupling optical elements 700, 710, 720 are not vertically aligned. Rather, the in-coupling optical elements are preferably non-overlapping (e.g., laterally spaced apart, as seen in the top-down view). As discussed further herein, this non-overlapping spatial arrangement facilitates the injection of light from different sources into different waveguides on a one-to-one basis, thereby allowing a specific light source to be uniquely coupled to a specific waveguide. In some implementations, an arrangement including non-overlapping spatially separated in-coupling optical elements may be referred to as a shifted pupil system, and the in-coupling optical elements in these arrangements may correspond to sub-pupils. It should be understood that the top and bottom views shown can be understood to be front plan views as viewed from the direction of the internally coupled beams of light (e.g., light 770, 780, 790 (FIG. 9B)) incident on the internal coupling elements 700, 710, 720, respectively.

[0213] 9D illustrates an example of a wearable display system 60 into which the various waveguide and associated systems disclosed herein may be integrated. In some implementations, the display system 60 is the system 250 of FIG. 6, which diagrammatically illustrates some portions of the system 60 in greater detail. For example, the waveguide assembly 260 of FIG. 6 may be part of the display 70.

[0214] 9D, the display system 60 includes a display 70 and various mechanical and electronic modules and systems to support the functions of the display 70. The display 70 may be coupled to a frame 80, which is wearable by a display system user or viewer 90 and configured to position the display 70 in front of the eye of the user 90. The display 70 may be considered an eyepiece in some implementations. In some implementations, a speaker 100 is coupled to the frame 80 and configured to be positioned adjacent to the ear canal of the user 90 (in some implementations, another speaker, not shown, may also be optionally positioned adjacent the user's other ear canal to provide stereo / shapeable sound control). The display system 60 may also include one or more microphones 110 or other devices to detect sound. In some implementations, the microphone may be configured to allow a user to provide input or commands to the system 60 (e.g., voice menu command selections, natural language questions, etc.) and / or enable audio communication with other persons (e.g., other users of a similar display system). The microphone may further be configured as an ambient sensor to collect audio data (e.g., sounds from the user and / or the environment). In some implementations, the display system may also include an ambient sensor 120a, which may be separate from the frame 80 and mounted on the body of the user 90 (e.g., the head, torso, limbs, etc. of the user 90). The ambient sensor 120a may, in some implementations, be configured to obtain data characterizing a physiological state of the user 90. For example, the sensor 120a may be an electrode.

[0215] 9D, the display 70 is operably coupled to the local data processing module 140 by a communication link 130, such as wired or wireless connectivity, which may be mounted in a variety of configurations, such as fixedly attached to the frame 80, fixedly attached to a helmet or hat worn by the user, embedded in headphones, or otherwise removably attached to the user 90 (e.g., in a backpack configuration, in a belt-connected configuration). Similarly, the sensor 120a may be operably coupled to the local data processing module 140 by a communication link 120b, such as wired or wireless connectivity. The local processing and data module 140 may comprise a hardware processor and digital memory, such as non-volatile memory (e.g., flash memory or hard disk drive), both of which may be utilized to aid in processing, caching, and storing data. Optionally, the local processing and data module 140 may include one or more central processing units (CPUs), graphics processing units (GPUs), dedicated processing hardware, and the like. The data may include a) data captured from sensors (such as image capture devices (such as cameras), microphones, inertial measurement units, accelerometers, compasses, GPS units, wireless devices, gyroscopes, and / or other sensors disclosed herein (e.g., which may be operatively coupled to the frame 80 or otherwise attached to the user 90)) and / or b) data acquired and / or processed using the remote processing module 150 and / or remote data repository 160 (including data related to virtual content), possibly for passing to the display 70 after processing or retrieval. The local processing and data module 140 may be operatively coupled to the remote processing module 150 and the remote data repository 160 by communication links 170, 180, such as via wired or wireless communication links, such that these remote modules 150, 160 are operatively coupled to each other and available as resources to the local processing and data module 140.In some implementations, local processing and data module 140 may include one or more of an image capture device, a microphone, an inertial measurement unit, an accelerometer, a compass, a GPS unit, a wireless device, and / or a gyroscope. In some other implementations, one or more of these sensors may be attached to frame 80 or may be a stand-alone structure that communicates with local processing and data module 140 by a wired or wireless communication path.

[0216] 9D , in some implementations, the remote processing module 150 may comprise one or more processors configured to analyze and process the data and / or image information, including, for example, one or more central processing units (CPUs), graphics processing units (GPUs), dedicated processing hardware, etc. In some implementations, the remote data repository 160 may comprise a digital data storage facility, which may be available through the Internet or other networking configurations in a "cloud" resource configuration. In some implementations, the remote data repository 160 may include one or more remote servers, which provide information, for example, information for generating augmented reality content to the local processing and data module 140 and / or the remote processing module 150. In some implementations, all data is stored and all calculations are performed in the local processing and data module, allowing for fully autonomous use from the remote modules. Optionally, an external system (e.g., one or more processors, one or more computer systems), including a CPU, GPU, etc., may perform at least a portion of the processing (e.g., generating image information, processing data) and provide information to and receive information from modules 140, 150, 160, e.g., via a wireless or wired connection. Exemplary Display Systems with Multiple External Coupling Regions

[0217] A display system described herein (e.g., display system 60, FIG. 9D ) may be used to present augmented or virtual reality content (referred to herein as virtual content). To present virtual content, the display system may direct light out of one or more waveguides using one or more out-coupling elements that out-couple the light in a direction such that the light propagates into one or both eyes of a user, such as a wearer of a head-mounted display.

[0218] 10A , the exemplary out-coupling element 830 out-couples light propagating in the waveguide toward the user's eye 1010 (e.g., by total internal reflection) as described herein. However, a typical out-coupling element may be structured to output light in various directions in all areas across the area of ​​the out-coupling optical element. Thus, a subset of the light out-coupled by the out-coupling optical element 830 may be usefully directed toward the pupil 1012 of the user's eye 1010, where it will enter the eye 1010 and form an image. The desirably directed light is illustrated by the exemplary beam 1015, which may extend normal or substantially normal to the out-coupling element 830 at locations near the center of the out-coupling element 830 (and may be angled inward for locations near the periphery of the out-coupling element 830). Other light that is outcoupled by the outcoupling element 830, such as beam 1017, that is outcoupled at various angles that do not impinge on the eye 1010 in a normal direction from the periphery of the outcoupling element 830 or at or near the pupil 1012, may not contribute to the image formed in the eye 1010. Such light that is outcoupled from the outcoupling optical element 830 but does not impinge on or near the pupil may be considered wasted energy. It should be understood that the drawings are schematic and not necessarily to scale, and thus the lateral distance between light beams 115 and 117 may be large relative to the eye 1010 shown.

[0219] Advantageously, some implementations increase the proportion of outcoupled toward the pupil 1012 of the user's eye 1010 (e.g., outcoupled light aligned with beam 1015) and reduce the amount of light outcoupled in other directions that are not aligned by the eye 1010 (e.g., outcoupled light aligned with beam 1017). For example, such a system may increase the proportion of incoupled light that ultimately enters the pupil, and thus reduce the amount of light energy that must be generated by a light projection system or other display light source to produce an image of a given brightness at the user's eye. Various implementations of the present technology provide a system including an outcoupling element, an incoupling element, and / or a light projection system configured to selectively direct image light toward the pupil 1012 of the user's eye 1010. Such systems may thereby advantageously improve the efficiency of the display systems disclosed herein, since they may increase the proportion of a given amount of light produced by the light projection system that reaches the eye 1010 and forms the image perceived by the user, and may reduce the proportion of light that hits other parts of the user's eye or face, or does not otherwise contribute to the image perceived by the user.

[0220] As illustrated diagrammatically in Figures 10B and 10C, some implementations may include segmenting the outcoupling element 1000 of the waveguide 900 into different outcoupling regions 1000a, 1000b, 1000c. The different outcoupling regions may be configured to outcouple light differently. For example, the outcoupling region 1000b may direct the outcoupled light beam 1015 with little or no outcoupled light 1017 being output from the other outcoupling regions 1000a, 1000c. As a result, light 1017 that does not enter the eye and is not perceived by the user is not "wasted" by not being output from the outcoupling regions 1000a, 1000c.

[0221] It should be understood that different out-coupling regions may direct the output light at angles other than normal to the out-coupling element 1000. FIG. 10C illustrates example light beam directions 1019 that may be associated with different out-coupling regions 1000a, 1000b, 1000c. In some implementations, different out-coupling regions may be utilized to out-couple light for different portions of the field of view. For example, it may be desirable for the central region 1000b of the out-coupling element 1000 to generally out-couple light along a set of angles that are generally centered around a direction that typically extends outward toward the eye 1010, while the peripheral regions 1000a, 1000c of the out-coupling element 1000 to generally out-couple light along a set of angles that are generally centered around a direction angled inward toward the eye 1010 and that enters the pupil of the eye. Thus, in some implementations, the field of view provided by the display system and / or the virtual content available in different portions of the field of view may be varied as desired by appropriate selection of the external coupling regions 1000a, 1000b, 1000c, as discussed herein. Advantageously, this ability to select different portions of the field of view (e.g., portions containing desired virtual content) promotes high energy utilization efficiency by allowing light from certain other directions not to be emitted.

[0222] It should be appreciated that in some implementations, a light projection system may be utilized to direct light into the waveguide 900, which may utilize projection optics to collimate the light for input into the waveguide 900. The image tiling approach disclosed herein advantageously enables the use of discrete light projectors for each or a plurality of different portions of the field of view, with each projector forming image content for an associated portion of the field of view. It should be appreciated that collimating light to provide image content across the entire field of view may require extensive and complex projection optics if a single light projector is utilized. On the other hand, projection optics for providing a relatively small field of view, e.g., a portion of the field of view of a display system, are advantageously simpler and smaller than projection optics for collimating light for a larger field of view. As discussed herein, the use of multiple light projectors may thus occupy a smaller total volume than the use of a single light projector for the entire field of view.

[0223] 10D illustrates an exemplary primary ray of light 1015 that may be outcoupled from a waveguide of an exemplary wearable display system. In some implementations, a single one of the outcoupling regions 1000a, 1000b, 1000c may be large enough to generate a desired field of view for the eye 1010. For example, the light ray 1015 that may be outcoupled from the outcoupling region 1000b may be dispersed within an area that includes or is smaller than the visual limit of the eye, or may provide a range of angles for the light incident on the eye to correspond to the desired field of view.

[0224] 11A , the waveguide 900 may have an external coupling element, such as an external coupling element 1000, which may include an array of diffractive or other light dispersing structures 1020 that cause the diffraction and propagation of light across the external coupling element 1000. In some implementations, the light dispersing structures 1020 and the external coupling element 1000 may be disposed on the same side of the waveguide 900, e.g., on the same major surface of the waveguide 900. In such implementations, the area occupied by the external coupling element 1000 may include structures (e.g., diffractive structures) that outcouple that light out of the waveguide and also structures (e.g., diffractive structures) that disperse incident light across the waveguide by total internal reflection.

[0225] In some other implementations, in the top-down view shown, the external coupling element 1000 may be seen to be directly below the optically dispersive element 1020. In such a configuration, the external coupling element 1000 and the optically dispersive element 1020 may be disposed on different opposing major surfaces of the waveguide 900.

[0226] 11A , when a light beam 1025 (e.g., corresponding to an image light) impinges on the internal coupling element 1005, the beam 1025 is internally coupled into the waveguide 900 and propagates in a propagation direction along one axis (e.g., the vertical axis) until it strikes the light dispersing structure 1020, which causes a portion of the beam 1025 to split into beamlets 1027, which generally occur in stages and may propagate along a different axis (e.g., an orthogonal or horizontal axis, as shown). Preferably, the internal coupling element 1005 redirects the light into the waveguide 900 at an angle such that the light beam 1025 propagates within the waveguide by total internal reflection. It should be understood that the light dispersing structure 1020 has a sufficiently low light redirecting efficiency to allow a majority of the beam 1025 to continue propagating (e.g., downward along the vertical axis). Thus, the beam 1025 may be replicated and fill substantially the entire area of ​​the outer coupling element 1000. Such an arrangement may provide uniform propagation and high coverage across the outer coupling element 1000, but may create challenges in targeting the propagation of the beamlets 1027 for efficient use of the light.

[0227] In some implementations, as shown in FIG. 11B, the waveguide 900 may have an out-coupling element 1000 that may be segmented into a left region 1000l and a right region 1000r. The left region 1000l may include only the light dispersing structure 1020l configured to cause the beamlet 1027l to propagate generally leftward and downward. Similarly, the right region 1000r may include only the light dispersing structure 1020r configured to cause the beamlet 1027r to propagate generally rightward and downward. Thus, each beam 1025 of light entering each region 1000l, 1000r is out-coupled from only the same one of the regions 1000l, 1000r and does not propagate to the other of the regions 1000l, 1000r. This configuration may improve the efficiency of the out-coupling element 1000 because the amount of area of ​​the out-coupling element 1000 over which each beam 1025 propagates is reduced by approximately half. It should be understood that in various implementations, further segmentation may be implemented to provide efficient use of the in-coupled light, for example, by including additional segmented regions and / or differently shaped segmented regions. The boundary between the left region 1000l and the right region 1000r may correspond to a physical dividing structure (e.g., an optically opaque and / or absorptive partition) or may simply be an interface between regions of the differently oriented light dispersing structures 1020r, 1020l.

[0228] 11C illustrates an example cross-sectional side view of the waveguide of FIG. 11B in an implementation in which the external coupling region and the light dispersing structure may be on different sides of the waveguide. For example, the external coupling region 1000r may be disposed on a first major surface of the waveguide 900, and the light dispersing structure 1020r may be disposed on a second, opposing major surface of the waveguide 900. In some implementations, as shown, the light dispersing structure 1020r may be vertically aligned with the external coupling region 1000r and occupy a similar area. As discussed herein, the external coupling region and the light dispersing structure may be diffractive structures, such as diffraction gratings, in some implementations.

[0229] 12A and 12B illustrate example configurations whereby the profile of the in-coupling element can be varied to improve efficient use of light within the imaging systems described herein. In FIGURES 12A and 12B, a waveguide 900 includes multiple discrete in-coupling regions.

[0230] 12A, the example waveguide 900 includes an external coupling element 1000 that includes regions 1000l, 1000c, and 1000r. Regions 1000l, 1000c, and 1000r may be physically segmented regions of the external coupling element 1000, or may be regions of the external coupling element 1000 that are not physically separated by any dividing structure, variations in the light dispersing structure, or other physical structure.

[0231] The exemplary display system further includes corresponding internal coupling elements 1005l, 1005c, 1005r configured to incoupling light incident on the internal coupling elements 1005l, 1005c, 1005r towards the external coupling element 1000. It should be understood that the light dispersing structure as shown in FIG. 11C may be disposed on an opposite major surface of the waveguide 900 to the major surface having the external coupling elements 1000. In some other implementations, the light dispersing structure and the light external coupling elements 1000 may be on the same major surface.

[0232] 12A , it may be desirable for the internal coupling element 1005c to incouple and direct light to a central region 1000c of the external coupling element 1000, where the light is equally distributed in both lateral directions. In some implementations, it may be desirable for the internal coupling element 1005c to direct the incoupled light within a range of angles that are generally symmetrically distributed about the axis 1025c. In addition, as shown, the internal coupling elements 1005l and 1005r may incouple light to the correlated regions 1000l, 1000r of the external coupling element 1000, where it may be more desirable for the light to be distributed inward toward the center of the external coupling element 1000, rather than toward the lateral edges of the external coupling element 1000 (e.g., because light that reaches the lateral edges of the external coupling element 1000 may be absorbed, outcoupled away from the eye, or otherwise not be effectively outcoupled). Thus, it may be desirable for the internal coupling elements 1005l and 1005r to direct the internally coupled light within a range of angles about the inwardly biased axes 1025l, 1025r to reduce the amount of light that reaches the side edges of the external coupling element 1000. In some implementations, the regions 1000l, 1000c, and 1000r may be understood as external coupling regions that define stripes across the waveguide 900, the stripes extending along axes that intersect the rows defined by the internal coupling regions 1005l, 1005c, and 1005r.

[0233] In some implementations, such as those in which the internal coupling elements 1005l, 1005c, 1005r include diffraction gratings, the internal coupling elements 1005l, 1005c, 1005r can achieve a desired directivity of the internal coupling based on the orientation of the internal coupling structures 1007. In the example implementation illustrated in Figure 12A, the internal coupling structures 1007 of the side internal coupling elements 1005l and 1005r are angled or biased in a certain direction relative to the orientation of the internal coupling structure 1007 of the central internal coupling element 1005c.

[0234] With continued reference to FIG. 12A, the regions 1000l, 1000c, 1000r and / or associated light dispersing structures 1020 (FIG. 11C) may be separated by optically opaque and / or absorptive partitions to limit the propagation of light between different ones of the correlation regions 1000l, 1000c, 1000r. In some other implementations, partitions are not provided between the different regions or their associated light dispersing structures. Rather, light directed into one out-coupling region may be allowed to propagate freely to the other out-coupling region. Such a configuration nevertheless provides advantages for efficient utilization of light, since the in-coupling region directs light primarily to a particular out-coupling region such that the entirety of the waveguide receives less light than that out-coupling region.

[0235] 12B illustrates a further example arrangement of internal coupling elements in conjunction with a non-rectangular external coupling element 1000. In the example implementation of FIG. 12B, the waveguide 900 includes an even number of internal coupling elements 10051, 10052, 10053, 10054, which in some implementations may be arranged in a generally symmetrical distribution about the center of the external coupling element 1000. Thus, because none of the internal coupling elements 10051, 10052, 10053, 10054 are centered across a central portion of the external coupling element 1000, all four internal coupling elements 10051, 10052, 10053, 10054 may be configured to have an inward bias. Because the internal coupling elements 10052 and 10053 are more centrally located relative to the internal coupling elements 10051 and 10054, the internal coupling elements 10052 and 10053 may have internal coupling structures 1007 that are less tilted relative to the internal coupling structures 1007 of the internal coupling elements 10051 and 10054, such that the internal coupling elements 10052 and 10053 incouple light into a larger central area of ​​the external coupling element 1000. The internal coupling elements 10051 and 10054 are located closer to the side edges of the external coupling element 1000, and therefore have more tilted internal coupling structures 1007, such that light incoupled by the internal coupling elements 10051 and 10054 has a greater inward bias and is less likely to impinge on the side edges of the external coupling element 1000.

[0236] Although the implementations illustrated in Figures 12A and 12B illustrate multiple discrete, spaced apart internal coupling regions, the waveguide 900 disclosed herein may also be implemented using one or more internal coupling regions in which continuous portions of individual optical internal coupling elements have differently configured light redirecting structures that define the different internal coupling regions thereof. For example, Figure 13 illustrates a waveguide having internal coupling elements that extend along two or more sides, i.e., lateral edges, of the waveguide. For example, as illustrated, the internal coupling elements 1005 may be disposed along multiple sides or edges of the waveguide and surround the external coupling element 1000. In some implementations, as illustrated, the internal coupling elements 1005 substantially surround the external coupling element 1000. The internal coupling elements 1005 include internal coupling structures 1007 that are arranged to internally couple light and direct the light toward the external coupling element 1000 in a particular desired direction. For example, the internal coupling structures 1007 located near the top of the external coupling element 1000 may be arranged to incouple light generally downward, the internal coupling structures 1007 located near the bottom of the external coupling element 1000 may be arranged to incouple light generally upward, and the internal coupling structures 1007 located near the lateral sides of the external coupling element 1000 may be arranged to incouple light generally inward toward the center of the external coupling element 1000. It should be understood that different regions of the internal coupling element 1005 having differently configured internal coupling structures 1007 may be understood to constitute different internal coupling regions.

[0237] In some embodiments, the light injection system may be configured to project light towards the internal coupling element 1005. The light injection system may include multiple projectors, which may have the advantage of simplifying the provision of light into the internal coupling element on different sides of the waveguide. As discussed herein, the full FOV of the display system may be subdivided into multiple portions, and the light injection system may include multiple projectors configured to provide image content for each associated portion by directing light to different areas of the internal coupling element 1005. Additionally or alternatively, the projectors may be oriented to direct light to portions of the internal coupling element 1005 on different sides of the waveguide 900. In some embodiments, the light injection system may include a first projector configured to direct light into a portion of the internal coupling element 1005 along a top edge of the waveguide 900, a second projector configured to direct light into a portion of the internal coupling element 1005 along a right edge of the waveguide 900, a third projector configured to direct light into a portion of the internal coupling element 1005 along a bottom edge of the waveguide 900, and a fourth projector configured to direct light into a portion of the internal coupling element 1005 along a left edge of the waveguide 900. It should be understood that the projectors may each be configured to provide image content for different portions of the external coupling element 1000, as discussed herein, the different portions being associated with different portions of the internal coupling optical element 1005.

[0238] 14A illustrates a further example configuration of a waveguide 900 having an internal coupling element for incoupling light into an external coupling element 1000. The internal coupling element 1005 includes individual internal coupling regions 1005. a1 …1005 d4 Each internal bond region 1005 may include a1 …1005 d4may be configured to incouple light that would be outcoupled from a corresponding or correlated external coupling region a1...d4 of the external coupling element 1000. The external coupling regions a1...d4 may define a grid pattern across the waveguide 900. Each internal coupling region 1005 a1 …1005 d4 The light incoupled at the incoupling region 1005 can be determined by changing the tilt, grating pitch, grating structure size (e.g., the size of the protrusions on the surface that form the grating), or the individual incoupling regions 1005. a1 …1005 d4 The inner coupling regions 1005 may be oriented to be outcoupled only or primarily from the corresponding outer coupling regions a1...d4 of the outer coupling element 1000 based on one or more characteristics of the inner coupling regions a1...d4, the inner coupling regions 1005 ... a2 , 1005 b2 , 1005 c2 , and 1005 d2 are the internal bond regions 1005 a2 , 1005 b2 , 1005 c2 , 1005 d2 The incoupling elements 1005 may differ in tilt, grating pitch, grating structure size, or another characteristic relative to the others, such that light incoupled by the incoupling elements 1005 is preferentially, or primarily, directed to and outcoupled by a particular associated outcoupling region. a2 may be configured such that light incoupled therefrom has an angle of total internal reflection within the external coupling element 1000 that causes the light to be incident on region a2. b2 may be configured such that the incoupling light therefrom has a different angle of total internal reflection within the waveguide 900 causing much of the light to travel further along the outcoupling element 1000 and be incident on the outcoupling region b2.

[0239] As discussed herein, the light injection system may include coupling light into different in-coupling regions 1005. a1 …1005 d4The light injection system may be configured to project light toward different in-coupling regions 1005. a1 …1005 d4 In some embodiments, the light injection system may include multiple projectors configured to direct a subset of the FOV into one or more inter-coupling regions 1005. a1 …1005 d4 For example, a first projector may be configured to emit light toward a subset of the internal coupling regions closer to a first side edge of the waveguide, and a second projector may be configured to emit light toward a subset of the internal coupling regions closer to a second side edge of the waveguide.

[0240] FIG. 14B is a schematic cross-sectional side view example of the waveguide of FIG. 14A, the cross section being taken along plane 14B (FIG. 14A). As shown, the internal coupling region 1005 a2 , 1005 b2 , 1005 c2 , 1005 d2 may receive an incident light beam 1025, which may be in-coupled and redirected towards the outer coupling regions a1, b1, c1, d1 of the outer coupling element 1000. a2 , 1005 b2 , 1005 c2 , 1005 d2 It should be appreciated that the incoupling region 1005 may be configured to incoupling light for propagation through the waveguide 900 by total internal reflection. In addition, when incoupling light, the incoupling region 1005 a2 , 1005 b2 , 1005 c2 , 1005 d2 The inner coupling region 1005 may be configured to deflect light at different angles, as shown. For example, a light beam 1025 is deflected by the inner coupling region 1005. a2 , 1005 b2 , 1005 c2 , 1005 d21205, respectively. a2 , 1025 b2 , 1025 c2 , 1025 d2 The in-coupled light beam 1205 may be provided. a2 , 1025 b2 , 1025 c2 , 1025 d2 , propagate at angles that cause them to subsequently impinge on the corresponding outcoupling regions a1, b1, c1, d1, respectively, by total internal reflection. In some implementations, the total internal reflection angle (the angle at which the incoupling light undergoes total internal reflection from a major surface of the waveguide) is adjusted to the incoupling regions 1005 such that the incoupling light is deflected and enters the waveguide at the desired total internal reflection angle. a2 , 1005 b2 , 1005 c2 , 1005 d2 (In some implementations, the angle for some internal coupling regions may be shallower than others).

[0241] In some implementations, the selectivity of correspondence between a particular internal coupling region and a particular external coupling region may be increased by configuring the external coupling regions such that they are most efficient at outcoupling light received from their associated internal coupling region. For example, an external coupling region may be configured to most efficiently outcouple incident light impinging thereon from an angle that corresponds to the angle of the incoupling light propagating from the associated internal coupling region. For example, an external coupling region may most efficiently outcouple light impinging thereon at a TIR angle provided by the associated internal coupling region, and / or an external coupling region may most efficiently outcouple light impinging thereon from a lateral direction that corresponds to the associated internal coupling region.

[0242] In some implementations, an image tiling approach may be utilized in conjunction with the example configuration of FIG. 14A. It should be understood that in some contexts, virtual content may be displayed only within a portion of the user's field of view. In some implementations, each of the regions a1...d4 may be associated with a particular portion of the field of view, and the image content to be output by a particular region a1...d4 may correspond to the virtual content for that portion of the field of view. In some cases, an image may span multiple regions a1...d4. Each internal coupling element 1005 a1 …1005 d4 The image light projected onto the outer coupling element 1000 may represent a section of the image that would appear in a corresponding region a1...d4 of the outer coupling element 1000. Thus, each image section may be projected onto a corresponding inner coupling element 1005. a1 …1005 d4 When projected onto the other inner coupling regions 1005, the image light for each image section is projected onto the other inner coupling regions 1005. a1 …1005 d4 The image light is outcoupled in its corresponding region a1...d4 of the outer-coupling element 1000 with an intensity greater than the light from the inner-coupling region a1...d4. In some implementations, the image light may be temporally multiplexed (directed into different inner-coupling regions at different times) such that a user viewing the outer-coupling element 1000 perceives a full image. When temporally multiplexed, the image light is provided to each outer-coupling region that is desired to output image light, preferably within a flicker fusion threshold.

[0243] It should be appreciated that the waveguide 900 may be one of multiple similar waveguides forming a waveguide stack, for example as illustrated in Figures 11A-14B. Such a waveguide stack may be advantageously utilized to provide virtual content on multiple depth planes, as discussed herein.

[0244] FIG. 14C illustrates a set 660A of stacked waveguides 670A, 680A, and 690A, which may be similar to waveguide 900 (FIGS. 11A-14B), respectively. Each waveguide includes one or more associated internal coupling regions 700A, 700B, 710A, 710B, 720A, and 720B (which may also be referred to as the light input area on the waveguide and may correspond to the optical internal coupling regions discussed with reference to FIGS. 12A-14C). The one or more internal coupling regions may include one or more internal coupling optical elements and may be configured to direct light into one or more external coupling elements 1000A, 1000B, and 1000C within its associated waveguide. The external coupling elements may be segmented into different regions as discussed herein. The configuration of the inner and outer coupling regions within each of the stacked waveguides may correspond to any of the disclosed example waveguide configurations, such as the waveguide configurations discussed with reference to any one of Figures 11A-14A.

[0245] As shown, the in-coupling optical regions 700A, 700B, 710A, 710B, 720A, and 720B may be laterally offset from one another. In some implementations, each in-coupling optical region may be offset to receive light without light passing through another in-coupling optical region. For example, each in-coupling region 700A, 700B, 710A, 710B, 720A, and 720B may be separated (e.g., laterally spaced) from the other in-coupling optical regions 700A, 700B, 710A, 710B, 720A, and 720B so as to not substantially receive light passing through others of the in-coupling optical elements 700A, 700B, 710A, 710B, 720A, and 720B. In some examples, one or more of the in-coupling optical regions may share an image input device or may receive light from different image input devices.

[0246] The waveguides may be spaced apart or separated in a manner similar to the waveguide stacks discussed with reference to FIG. 9A. In some implementations, the light beams 770, 780, 790 are intended for different waveguides (e.g., waveguides configured to output light with different amounts of wavefront divergence and / or configured to output light having different properties, such as different wavelengths or colors). Advantageously, the different waveguides may be selected by directing light into different internal coupling regions, thereby providing image light outputs with different amounts of wavefront divergence. Thus, in some implementations, a particular internal coupling region may be associated with a particular waveguide (to internally couple light into that waveguide) and also with a particular external coupling region within that waveguide (to direct the internally coupled light towards the associated external coupling region). (Directing light to the outcoupling area)

[0247] The display system may selectively direct light to one or more out-coupling regions of a display by identifying a region for outputting image light and directing the image light to that out-coupling region. Figure 15 illustrates an exemplary light directing process 3000 for directing light to an out-coupling region of a display.

[0248] Continuing with reference to FIG. 15, in block 3002, the display system may determine a desired location of a virtual object on a display, which may include a waveguide, having a viewing area, which may include an external coupling element segmented into multiple external coupling regions. If the display system is an AR or VR system, the system may identify a desired and / or perceived location in the user's 3D environment for displaying the virtual object and determine an associated location within the area in the display. For example, an application of the display system may send instructions to the display system to display a virtual object, such as a butterfly, at a specified location in the user's physical environment. The display system may determine that the specified location corresponds to a projected location of the virtual object on the display, such as the upper right corner of the display. For example, the area of ​​the display that provides image light to form the virtual object may correspond to an expected intersection between the viewing area of ​​the display and an expected path of light from the virtual object to the pupil of the eye.

[0249] The projected location on the display may include the entire area of ​​the display over which the virtual object may be projected. For example, if the virtual object is a large object, such as a tree, that may occupy a large portion of the user's field of view, the desired location may include a large percentage area of ​​the display. In another example, if the virtual object is a small object, such as a butterfly, that will occupy a small portion of the user's field of view, the desired location may include a small percentage area of ​​the display. In another example, the display system may display more than one virtual object. In an example involving more than one virtual object, the display system may determine multiple locations, areas, or regions of the display for displaying the virtual object.

[0250] It should be understood that the representation of the virtual object in the 3D space may take into account the eye posture of the user, and the area of ​​the display for displaying the virtual object may change over time as the eye posture of the user changes. For example, the location of the virtual object may be anchored to a physical object, and the location of the virtual object in the user's field of view may change as the user's eyes move relative to the physical object that serves as the anchor, which may cause a corresponding change in the area of ​​the display that is utilized to output image light. The display system may identify the user's eye posture based on one or more eye tracking processes, as discussed herein. In some implementations, as discussed herein, to provide the perception of the virtual object as being at a location in the user's 3D environment, the display may output light from a location on the external coupling element that is associated with the location, such that the light propagates to the eye from a direction corresponding to the location.

[0251] In block 3004, the display system may identify one or more external binding regions associated with the determined locations. For example, the display may include multiple external binding regions. One or more determined locations or areas of the display may span across one or more external binding regions. The display system may identify external binding regions associated with locations or areas of the display that correlate to one or more displayed virtual objects.

[0252] In block 3006, the display system may send instructions to output light to the identified one or more outer coupling regions. For example, the display system may send instructions to a controller to project light to an inner coupling region associated with the identified outer coupling region. For example, the inner coupling region may include one or more light redirecting structures, such as one or more diffraction gratings. The display system may selectively direct light to the inner coupling region using a light injection system as discussed with reference to FIGS. 20-22.

[0253] In some other implementations, the display system may display different representations of the virtual object depending on the eye posture of the user. For example, the display system may utilize foveated rendering techniques to reduce the resolution of the virtual content based on, for example, the distance of the virtual object from the center (e.g., fixation point) of the user's field of view to reduce the amount of computational work involved in displaying the virtual content. For example, the display system may be configured to display the virtual object at a relatively high (e.g., full) resolution when the virtual object coincides with the fixation point of the user's eye and to display the virtual object at a relatively low resolution when the virtual object is at the periphery of the user's field of view. Foveated rendering techniques are discussed in U.S. Patent Application Publication No. 2018 / 0275410, published September 27, 2018 and entitled "DEPTH BASED FOVEATED RENDERING FOR DISPLAY SYSTEMS," the entire disclosure of which is incorporated herein by reference. Example of region determination using eye pose determination

[0254] 15, the desired location of the display for outputting image light may be determined based, at least in part, on the user's eye posture. For example, as discussed above, the desired location may correspond to an intersection within the viewing area of ​​the display (e.g., on a waveguide) of light from a 3D location of a virtual object in the user's environment to the pupil of the user's eye.

[0255] Alternatively, for at least some content (e.g., display system menu items and alerts, or other content that is not anchored to a location in the physical world), the area of ​​the display for outputting image light may be selected simply based on the user's eye posture. For example, a display system menu may simply be tied to the user's eye posture such that the menu remains in the user's field of view regardless of eye posture.

[0256] FIG. 16 is an example of a flow chart of an external binding location determination process 3100 using eye posture. In block 3102, the display system may receive one or more eye images from an imaging system. The imaging system may include an inwardly facing imaging system, such as one or more cameras, associated with a display of the display system. The imaging system may be configured to image the left and / or right eye of a user. As described in more detail below with reference to FIG. 17A, the eye image may include an image of the eye that includes one or more features of the eye, such as the eyelid, sclera, iris, and pupil.

[0257] In block 3104, the display system may determine an eye pose of the user's eye. For example, the display system may analyze one or more eye images to determine the eye pose. In some embodiments, the eye pose may include a center of rotation of the user's eye, a gaze direction, other orientation of the user's eye, or some combination thereof. As described in more detail with reference to FIGS. 17B and 32C, the display system may utilize one or more eye tracking modules to analyze the images and identify the eye pose.

[0258] In block 3106, the display system may utilize the eye pose to determine regions of the display associated with the eye pose for rendering virtual content. For example, the display system may utilize one or more engines to calculate display positions on the display for rendering virtual content at various locations relative to the eye pupil, e.g., along a vector that intersects with a center of rotation or perspective of the user's eye, as described in detail with reference to Figures 17B and 32C. Example Eye Images for Use in Eye Tracking

[0259] 17A illustrates an image of an eye 3200 with eyelid 3204, sclera 3208 (the "white" of the eye), iris 3212, and pupil 3216. Curve 3216a indicates the pupillary boundary between pupil 3216 and iris 3212, and curve 3212a indicates the limbal boundary between iris 3212 and sclera 3208. Eyelid 3204 includes upper eyelid 3204a and lower eyelid 3204b. Eye 3200 is illustrated in a natural resting position (e.g., both the user's face and gaze are oriented such that they would be directed toward a distant object directly in front of the user). The natural resting position of the eye 3200 may be indicated by the natural resting direction 3200, which is a direction perpendicular to the surface of the eye 3200 when in the natural resting position (e.g., straight out from the plane for the eye 3200 shown in FIG. 17A ) and, in this embodiment, is centered within the pupil 3216.

[0260] As the eye 3200 moves to face different objects, the eye pose will change with respect to the natural resting direction 3200. The current eye pose may be determined with reference to the eye pose direction 3204, which is a direction perpendicular to the surface of the eye (and centered within the pupil 3216), but oriented toward the object to which the eye is currently pointed. With reference to the exemplary coordinate system shown in FIG. 17A, the pose of the eye 3200 may be represented as two angular parameters indicating the azimuth and zenith deflections of the eye pose direction 3204 of the eye, both relative to the natural resting direction 3200 of the eye. For illustrative purposes, these angular parameters may be represented as θ (azimuth deflection, determined from the origin azimuth) and φ (zenith deflection, sometimes also referred to as polar deflection). In some implementations, the angular roll of the eye about the eye pose direction 3204 may be included in the determination of the eye pose, and the angular roll may be included in the subsequent analysis. In other implementations, other techniques for determining eye pose may be used, such as pitch, yaw, and optionally roll systems.

[0261] The eye images may be obtained from the video using any suitable process, for example, using video processing algorithms that may extract images from one or more sequential frames. The eye pose may be determined from the eye images using various eye tracking techniques. For example, the eye pose may be determined by considering the lens effect of the cornea on the provided light source. Any suitable eye tracking technique may be used to determine the eye pose. (Eye Tracking System Example)

[0262] FIG. 17B illustrates a schematic diagram of a wearable system 3230 including an eye tracking system. The wearable system 3230 may, at least in some implementations, include components located in a head mounted unit 3232 and components located in a non-head mounted unit 3234. The non-head mounted unit 3234 may be, as examples, a belt mounted component, a handheld component, a component in a backpack, a remote component, etc. Incorporating some of the components of the wearable system 3230 into the non-head mounted unit 3234 may help reduce the size, weight, complexity, and cost of the head mounted unit 3232. In some implementations, some or all of the functionality described as being implemented by one or more components of the head mounted unit 3232 and / or the non-head mounted unit 3234 may be provided using one or more components included anywhere in the wearable system 3230. For example, some or all of the functionality described below associated with the CPU 3242 of the head mounted unit 3232 may be provided using the CPU 3246 of the non-head mounted unit 3234, or vice versa. In some embodiments, some or all of such functionality may be provided using peripheral devices of the wearable system 3230. Furthermore, in some implementations, some or all of such functionality may be provided using one or more cloud computing devices or other remotely located computing devices, in a manner similar to that described above with reference to FIG. 9D. In addition, it should be understood that the wearable system 3230 may correspond to the display system 60 (FIG. 9D), and in some implementations the head mounted unit 3232 and the non-head mounted unit 3234 may correspond to the local data processing module 140 and the remote processing module 150, respectively.

[0263] As shown in FIG. 17B, the wearable system 3230 may include an eye tracking system including a camera 3270 that captures an image of the user's eye 3240. If desired, the eye tracking system may also include light sources 3260a and 3260b (such as light emitting diodes "LEDs" that may emit visible light in some implementations or non-visible light, e.g., infrared light in other implementations). The light sources 3260a and 3260b may generate a flash of light (e.g., a reflection from the user's eye that appears in an image of the eye captured by the camera 3270). The position of the light sources 3260a and 3260b relative to the camera 3270 may be known, so that the position of the flash of light in the image captured by the camera 3270 may be used in tracking the user's eye (as will be discussed in more detail below). In at least one implementation, there may be one light source 326 and one camera 3270 associated with a single one of the user's eyes 3240. In another implementation, there may be one light source 326 and one camera 3270 associated with both of the user's eyes 3240. In yet other implementations, there may be one or more light sources 326 and one or more cameras 3270 associated with one or each of the user's eyes 3240. As a specific example, there may be two light sources 3260a and 3260b and one or more cameras 3270 associated with each of the user's eyes 3240. As another example, there may be three or more light sources, such as light sources 3260a and 3260b, and one or more cameras 3270 associated with each of the user's eyes 3240. In some implementations described herein, two or more cameras may be employed to image a given eye.

[0264] The eye tracking module 3244 may receive images from the eye tracking camera 324 and may analyze the images and extract various information. As examples, the eye tracking module 3244 may detect the user's eye posture, the three-dimensional position of the user's eyes relative to the eye tracking camera 3270 (and head mounted unit 3232), the direction in which one or both of the user's eyes 3240 are focused, the user's convergence-divergence depth (e.g., the depth from the user at which the user is focused), the position of the user's pupils, the position of the user's cornea and / or corneal sphere, the center of rotation of one or each of the user's eyes, and the center of perspective of one or each of the user's eyes, or any combination thereof. The eye tracking module 3244 may extract such information using techniques described below in connection with FIG. 17C below. As shown in FIG. 17B, the eye tracking module 3244 may be a software module that, in some implementations, is implemented using the CPU 3242 in the head mounted unit 3232.

[0265] Although one camera 3270 is shown imaging the eye in FIG. 17B , in some implementations as discussed herein, multiple cameras may image the eye and be used for measurements such as corneal center and / or center of rotation measurements, or otherwise used for eye tracking or other purposes.

[0266] Data from the eye tracking module 3244 may be provided to other components within the wearable system. As an example, such data may be transmitted to components within the non-head mounted unit 3234, such as the CPU 3246, which includes software modules for a light field rendering controller 3248 and an alignment observer 3250.

[0267] The rendering controller 3248 may use information from the eye tracking module 3244 to adjust the images displayed to the user by the rendering engine 3252 (e.g., a rendering engine, which may be a software module within the GPU 3250 and may provide images to the display 220). As an example, the rendering controller 3248 may adjust the images displayed to the user based on the user's center of rotation or perspective. In particular, the rendering controller 3248 may use information about the user's center of perspective to simulate a rendering camera (e.g., simulate the collection of images from the user's viewing height) and adjust the images displayed to the user based on the simulated rendering camera.

[0268] A "rendering camera", sometimes referred to as a "pinhole perspective camera" (or simply, a "perspective camera") or a "virtual pinhole camera" (or simply, a "virtual camera"), is a simulated camera for use in rendering virtual image content, possibly from a database of objects in a virtual world. The objects may have a location and orientation relative to the user or wearer, and possibly relative to real objects in the environment surrounding the user or wearer. In other words, the rendering camera may represent a viewing height in the rendering space from which the user or wearer should view the 3D virtual content (e.g., virtual objects) of the rendering space. The rendering camera may render a virtual image based on a database of virtual objects to be presented to the eye, managed by a rendering engine. The virtual image may be rendered as if captured from the viewing height of the user or wearer. For example, a virtual image may be rendered as if it were captured by a pinhole camera (corresponding to a "rendering camera") with a specific set of intrinsic parameters (e.g., focal length, camera pixel size, principal point coordinates, distortion / warping parameters, etc.) and a specific set of extrinsic parameters (e.g., translation and rotation components relative to the virtual world). The virtual image is captured from the viewing height of such a camera with the rendering camera's position and orientation (e.g., the rendering camera's extrinsic parameters). It follows that the system may define and / or adjust the intrinsic and extrinsic rendering camera parameters. For example, the system may define a set of specific extrinsic rendering camera parameters such that a virtual image may be rendered as if it were captured from a viewing height of a camera having a specific location relative to the user's or wearer's eyes to provide an image that appears as if it were from the user's or wearer's viewing height. The system may later dynamically adjust the extrinsic rendering camera parameters on the fly to maintain alignment with the specific location. Similarly, intrinsic rendering camera parameters may also be defined and dynamically adjusted over time.In some implementations, the image is rendered as if it were captured from the viewing height of a camera with an aperture (e.g., a pinhole) at a specific location (such as the perspective center or rotation center or anywhere) relative to the user's or wearer's eye.

[0269] In some implementations, the system may create, or dynamically reposition and / or reorient, one rendering camera for the user's left eye and another rendering camera for the user's right eye as the user's eyes are physically separated from one another and thus consistently positioned in different locations. It follows that in at least some implementations, virtual content rendered from a viewing height of a rendering camera associated with the viewer's left eye may be presented to the user through a left eyepiece of a head mounted display (e.g., head mounted unit 3232), and virtual content rendered from a viewing height of a rendering camera associated with the user's right eye may be presented to the user through a right eyepiece of such head mounted display. Further details discussing the creation, adjustment, and use of rendering cameras in the rendering process are provided in U.S. patent application Ser. No. 15 / 274,823, entitled "METHODS AND SYSTEMS FOR DETECTING AND COMBINING STRUCTURAL FEATURES IN 3D RECONSTRUCTION," which is expressly incorporated by reference in its entirety herein for all purposes.

[0270] In some examples, one or more modules (or components) of system 3230 (e.g., light field rendering controller 3248, rendering engine 3250, etc.) may determine a position and orientation of a rendering camera in a rendering space based on a user's head and eye position and orientation (e.g., as determined based on head pose and eye tracking data, respectively). That is, system 3230 may in effect map the user's head and eye position and orientation to a particular location and angular position in the 3D virtual environment, place and orient the rendering camera to a particular location and angular position in the 3D virtual environment, and render the virtual content for the user as it would be captured by the rendering camera. Further details discussing the real-world to virtual-world mapping process are provided in U.S. Patent Application No. 15 / 296,869, entitled "SELECTING VIRTUAL OBJECTS IN A THREE-DIMENSIONAL SPACE," which is expressly incorporated herein by reference in its entirety for all purposes. As an example, the rendering controller 3248 may adjust the depth at which an image is displayed by selecting the depth plane (or depth planes) that will be utilized to display the image at any given time. In some implementations, such a depth plane switch may be performed through adjustment of one or more intrinsic rendering camera parameters. For example, the light field rendering controller 3248 may adjust the focal length of the rendering camera when performing a depth plane switch or adjustment. As described in more detail below, depth planes may be switched based on a determined vergence-divergence movement of the user or a fixed depth.

[0271] The alignment observer 3250 may use information from the eye tracking module 3244 to identify whether the head mounted unit 3232 is properly positioned on the user's head. As an example, the eye tracking module 3244 may provide eye location information, such as the location of the center of rotation of the user's eyes, indicating the three-dimensional position of the user's eyes relative to the camera 3270 and the head mounted unit 3232, and the eye tracking module 3244 may use the location information to determine whether the display 220 is properly aligned within the user's field of view or whether the head mounted unit 3232 (or headset) has slipped or is otherwise misaligned with the user's eyes. As examples, the alignment observer 3250 may be able to determine whether the head mounted unit 3232 has slipped off the bridge of the user's nose, thus moving the display 220 downward and away from the user's eyes (which may be undesirable), whether the head mounted unit 3232 has moved above the bridge of the user's nose, thus moving the display 220 closer to the user's eyes and upward, whether the head mounted unit 3232 has shifted left or right relative to the bridge of the user's nose, whether the head mounted unit 3232 has lifted above the bridge of the user's nose, or whether the head mounted unit 3232 has moved away from a desired position or range of positions in these or other ways. In general, the alignment observer 3250 may be able to determine whether the head mounted unit 3232, and in particular the display 220, are properly positioned in front of the user's eyes. In other words, the alignment observer 3250 may determine whether the left display in display system 220 is properly aligned with the user's left eye, and the right display in display system 220 is properly aligned with the user's right eye. The alignment observer 3250 may determine whether the head mounted unit 3232 is properly positioned by determining whether the head mounted unit 3232 is positioned and oriented within a desired range of positions and / or orientations relative to the user's eyes.

[0272] In at least some implementations, the alignment observer 3250 may generate user feedback in the form of an alert, message, or other content. Such feedback may be provided to the user to inform the user of any misalignment of the head mounted unit 3232, along with optional feedback on how to correct the misalignment (such as a suggestion to adjust the head mounted unit 3232 in a particular manner).

[0273] Exemplary alignment observation and feedback techniques that may be utilized by the alignment observer 3250 are described in U.S. Pat. No. 10,573,042, entitled "PERIOCULAR TEST FOR MIXED REALITY CALIBRATION," issued February 25, 2020, and U.S. Patent Application Publication No. 2019 / 0222830, entitled "DISPLAY SYSTEMS AND METHODS FOR DETERMINING REGISTRATION BETWEEN A DISPLAY AND A USER'S EYES," published July 18, 2019 (both of which are incorporated by reference in their entirety into this specification). (Example of an Eye Tracking Module for Eye Pose Determination)

[0274] A block diagram of an example eye tracking module 614 that may be utilized to determine eye pose is shown in FIG. 17C. As shown in FIG. 17C, the eye tracking module 614 may include a variety of different sub-modules, may provide a variety of different outputs, and may utilize a variety of available data in tracking the user's eyes. As an example, the eye tracking module 614 may utilize available data including eye tracking extrinsic and intrinsic properties such as the geometry of the eye tracking camera 3270 relative to the light source 326 and the head mounted unit 602, assumed eye dimensions 3304 such as a typical distance of about 4.7 mm between the center of the user's corneal curvature and the average center of rotation of the user's eye or a typical distance between the user's center of rotation and center of perspective, and per-user calibration data 3306 such as the interpupillary distance of a particular user. Additional examples of extrinsic properties, intrinsic properties, and other information that may be employed by the eye tracking module 614 are described in U.S. patent application Ser. No. 15 / 497,726, entitled “IRIS BOUNDARY ESTIMATION USING CORNEA CURVATURE,” filed April 26, 2017, and issued as U.S. Patent No. 10,296,792 on May 21, 2019 (Attorney Docket No. MLEAP.023A7), which is incorporated by reference in its entirety into this specification.

[0275] The image pre-processing module 3280 may receive images from an eye camera, such as eye camera 3270, and may perform one or more pre-processing (e.g., adjustment) operations on the received images. As examples, the image pre-processing module 3280 may apply Gaussian blur to the images, downsample the images to a lower resolution, apply an unsharp mask, apply an edge sharpening algorithm, or apply other suitable filters that aid in the subsequent detection, location, and labeling of phosphenes, pupils, or other features in the images from the eye camera 3270. The image pre-processing module 3280 may apply a low-pass filter or a morphological filter, such as an open filter, which may remove high frequency noise, such as from the pupil boundary 516a (see FIG. 5), thereby removing noise that may interfere with pupil and phosphene determination. The image pre-processing module 3280 may output the pre-processed images to the pupil identification module 3282 and the phosphene detection and labeling module 3284.

[0276] The pupil identification module 3282 may receive pre-processed images from the image pre-processing module 3280 and may identify regions of those images that contain the user's pupil. The pupil identification module 3282 may, in some implementations, determine the coordinates of the location or the coordinates of the center or centroid of the user's pupil in the eye tracking images from the camera 3270. In at least some implementations, the pupil identification module 3282 may identify a contour (e.g., a contour of the pupil-iris boundary) in the eye tracking images, identify a contour moment (e.g., a center of mass), apply a starburst pupil detection and / or a Canny edge detection algorithm, based on intensity values, eliminate outliers, identify sub-pixel boundary points, correct for eye camera distortion (e.g., distortion in the images captured by the eye camera 3270), apply a random sample consensus (RANSAC) iterative algorithm, fit an ellipse to the boundaries in the eye tracking images, apply a tracking filter to the images, and identify sub-pixel image coordinates of the centroid of the user's pupil. The pupil identification module 3282 may output pupil identification data (which may indicate areas of the pre-processed image module 3282 identified as indicative of the user's pupil) to the flash detection and labeling module 3284. The pupil identification module 3282 may provide 2D coordinates of the user's pupil in each eye tracking image (e.g., 2D coordinates of the centroid of the user's pupil) to the flash detection module 3284. In at least some implementations, the pupil identification module 3282 may also provide the same type of pupil identification data to a coordinate system normalization module 3288.

[0277] Pupil detection techniques that may be utilized by the pupil identification module 3282 are described in U.S. Patent Publication No. 2017 / 0053165, published February 23, 2017, and U.S. Patent Publication No. 2017 / 0053166, published February 23, 2017 (each of which is incorporated by reference in its entirety into this specification).

[0278] The flash detection and labeling module 3284 may receive the pre-processed image from module 3280 and the pupil identification data from module 3282. The flash detection module 3284 may use this data to detect and / or identify flashes (e.g., reflections of light from the light source 326 off the user's eye) in areas of the pre-processed image that are indicative of the user's pupil. As an example, the flash detection module 3284 may search for bright areas in the eye tracking image, sometimes also referred to herein as "blobs" or local intensity maxima, that are in the vicinity of the user's pupil. In at least some implementations, the flash detection module 3284 may rescale (e.g., expand) the pupil ellipse to include the additional flashes. The flash detection module 3284 may filter the flashes by size and / or intensity. The flash detection module 3284 may also determine the 2D location of each of the flashes in the eye tracking image. In at least some examples, the flash detection module 3284 may determine the 2D location of the flash relative to the user's pupil, which may also be referred to as the pupil-flash vector. The flash detection and labeling module 3284 may label the flashes and output a pre-processed image with the labeled flashes to the 3D corneal center estimation module 3286. The flash detection and labeling module 3284 may also inherit data such as the pre-processed image from module 3280 and the pupil identification data from module 3282. In some implementations, the flash detection and labeling module 3284 may determine the light source (e.g., from among multiple light sources of the system, including infrared light sources 326a and 326b) that produced each identified flash. In these examples, the flash detection and labeling module 3284 may label the flashes with information identifying the associated light source and output a pre-processed image with the labeled flashes to the 3D corneal center estimation module 3286.

[0279] Pupil and flash detection as implemented by modules such as modules 3282 and 3284 may use any suitable technique. As an example, edge detection may be applied to the eye image to identify flashes and pupils. Edge detection may be applied by various edge detectors, edge detection algorithms, or filters. For example, a Canny edge detector may be applied to the image to detect edges, such as within a line of the image. Edges may include points located along a line that correspond to a local maximum derivative. For example, the pupil boundary 516a (see FIG. 5) may be located using a Canny edge detector. Using the determined pupil location, various image processing techniques may be used to detect the "pose" of the pupil 116. Determining the eye pose of the eye image may also be referred to as detecting the eye pose of the eye image. Pose may also be referred to as gaze, facing direction, or eye orientation. For example, the pupil may be facing left toward the object, and the pupil pose may be classified as a leftward pose. Other methods may also be used to detect the location of the pupil or flash. For example, concentric rings may be located in the eye image using a Canny edge detector. As another example, an integro-differential operator may be used to find the limbal boundary of the pupil or iris. For example, a Daugman integro-differential operator, a Hough transform, or other iris segmentation technique may be used to return a curve that estimates the boundary of the pupil or iris.

[0280] The 3D corneal center estimation module 3286 may receive pre-processed images, including detected phosphene data and pupil identification data, from modules 3280, 3282, 3284. The 3D corneal center estimation module 3286 may use these data to estimate the 3D position of the user's cornea. In some implementations, the 3D corneal center estimation module 3286 may estimate the center of curvature of the eye's cornea or the 3D position of the user's corneal sphere, e.g., the center of an imaginary sphere having a surface portion that is generally coextensive with the user's cornea. The 3D corneal center estimation module 3286 may provide data indicating the estimated 3D coordinates of the corneal sphere and / or the user's cornea to the coordinate system normalization module 3288, the optical axis determination module 3292, and / or the light field rendering controller 618. Further details of the operation of the 3D corneal center estimation module 3286 are provided herein in connection with Figures 11-16C. Exemplary techniques for estimating the position of ocular features such as the cornea or corneal sphere that may be utilized by the 3D corneal center estimation module 3286 and other modules in the wearable system of the present disclosure are discussed in U.S. patent application Ser. No. 15 / 497,3296, filed April 26, 2017 (Attorney Docket No. MLEAP.023A7), which is incorporated by reference in its entirety into this specification.

[0281] A coordinate system normalization module 3288 may optionally be included within the eye tracking module 614 (as indicated by its dashed outline). The coordinate system normalization module 3288 may receive data from the 3D corneal center estimation module 3286, and may also receive data from other modules, indicating the estimated 3D coordinates of the center of the user's cornea (and / or the center of the user's corneal sphere). The coordinate system normalization module 3288 may normalize the eye camera coordinate system, which may help to compensate for slippage of the wearable device (e.g., slippage of a head-mounted component from its normal resting position on the user's head, which may be identified by the alignment observer 620). The coordinate system normalization module 3288 may rotate the coordinate system to align the z-axis (e.g., vergence-divergence depth axis) of the coordinate system with the corneal center (e.g., as indicated by the 3D corneal center estimation module 3286) and may translate the camera center (e.g., origin of the coordinate system) a predetermined distance away from the corneal center, such as 30 mm (e.g., module 3288 may scale the eye tracking image depending on whether the eye camera 3270 is determined to be closer or farther away than the predetermined distance). Using this normalization process, the eye tracking module 614 may be able to establish a consistent orientation and distance within the eye tracking data relatively independent of variations in the headset being positioned on the user's head. The coordinate system normalization module 3288 may provide the 3D coordinates of the center of the cornea (and / or corneal sphere), the pupil identification data, and the pre-processed eye tracking images to the 3D pupil center locator module 3290.

[0282] The 3D pupil center locator module 3290 may receive data including the 3D coordinates of the center of the user's cornea (and / or corneal sphere), pupil location data, and pre-processed eye tracking images, in a normalized or unnormalized coordinate system. The 3D pupil center locator module 3290 may analyze such data and determine the 3D coordinates of the user's pupil center, in a normalized or unnormalized eye camera coordinate system. The 3D pupil center locator module 3290 may determine the location of the user's pupil in three dimensions based on the 2D location of the pupil centroid (as determined by module 3282), the 3D location of the corneal center (as determined by module 3286), assumed eye dimensions 3304 such as the size of a typical user's corneal sphere and the typical distance from the corneal center to the pupil center, and optical properties of the eye such as the refractive index of the cornea (relative to the refractive index of air), or any combination thereof. Techniques for estimating the position of eye features, such as the pupil, that may be utilized by the 3D pupil center locator module 3290 and other modules in the wearable system of the present disclosure are discussed in U.S. patent application Ser. No. 15 / 497,3296, filed Apr. 26, 2017 (Attorney Docket No. MLEAP.023A7), which is incorporated by reference in its entirety herein.

[0283] Optical axis determination module 3292 may receive data from modules 3286 and 3290 indicating the 3D coordinates of the user's cornea and the user's pupil center. Based on such data, optical axis determination module 3292 may identify a vector from the location of the corneal center (e.g., from the center of the corneal sphere) to the user's pupil center, which may define the optical axis of the user's eye. Optical axis determination module 3292 may provide outputs to modules 3294, 3298, 3310, and 3312 that define the user's optical axis, as an example.

[0284] The center of rotation (CoR) estimation module 3294 may receive data from module 3292, including parameters of the optical axis of the user's eye (e.g., data indicating the orientation of the optical axis in a coordinate system with a known relationship to the head mounted unit 602). For example, the CoR estimation module 3294 may estimate the center of rotation of the user's eye. The center of rotation may indicate a point around which the user's eye rotates as the user's eye rotates left, right, up, and / or down. Although the eye may not rotate perfectly around a single point, assuming a single point may be sufficient. In at least some implementations, the CoR estimation module 3294 may estimate the center of rotation of the eye by moving a specific distance along the optical axis (identified by module 3292) from the pupil center (identified by module 3290) or the center of corneal curvature (as identified by module 3286) toward the retina. This specific distance may be the assumed eye dimension 3304. As an example, the particular distance between the corneal center of curvature and the CoR may be approximately 4.7 mm. This distance may be varied for a particular user based on any relevant data, including the user's age, sex, vision prescription, other relevant characteristics, etc.

[0285] In at least some implementations, the CoR estimation module 3294 may refine its estimate of the center of rotation of each of the user's eyes over time. As an example, as time passes, the user will eventually rotate their eyes (to look elsewhere, something closer, something further away, or occasionally to the left, right, up, or down), causing a shift in the optical axis of each of their eyes. The CoR estimation module 3294 may then analyze the two (or more) optical axes identified by module 3292 and locate a 3D point of intersection of those optical axes. The CoR estimation module 3294 may then determine that the center of rotation is at that 3D point of intersection. Such techniques may provide an estimate of the center of rotation with improving accuracy over time.

[0286] Various techniques may be employed to increase the accuracy of the CoR estimation module 3294 and the determined CoR positions of the left and right eyes. As an example, the CoR estimation module 3294 may estimate the CoR by finding the average point of intersection of the optical axes determined over time for a variety of different eye postures. As an additional example, the module 3294 may filter or average the estimated CoR positions over time, may calculate a moving average of the estimated CoR positions over time, and / or may apply a Kalman filter and known dynamics of the eye and eye tracking system to estimate the CoR positions over time. In some implementations, a least squares approach may be taken to determine one or more points of intersection of the optical axes. In such implementations, the system may identify as the intersection of the optical axes locations at which, at a given time, the sum of the squared distances to a given set of optical axes is reduced or minimized. As a specific example, module 3294 may calculate a weighted average of the determined optical axis intersection and the assumed CoR location (e.g., 4.7 mm behind the center of curvature of the eye's cornea) so that as eye tracking data for a user is acquired, the determined CoR may slowly drift over time from the assumed CoR location (e.g., 4.7 mm behind the center of curvature of the eye's cornea) to a slightly different location within the user's eye, thereby enabling per-user refinement of the CoR location.

[0287] Under ideal conditions, the 3D position of the true CoR of the user's eye relative to the HMD should change over time by a negligible or minimal amount as the user moves his / her eye (e.g., as the user's eye rotates around its center of rotation). In other words, for a given set of eye movements, the 3D position of the true CoR of the user's eye (relative to the HMD) should hypothetically not vary over time as much as any other point along the optical axis of the user's eye. It therefore follows that the further a point along the optical axis is from the true CoR of the user's eye, the more variation or variance its 3D position will exhibit over time as the user moves his / her eye. In some implementations, the CoR estimation module 3294 and / or other sub-modules of the eye tracking module 614 may utilize this statistical relationship to improve CoR estimation accuracy. In such an implementation, the CoR estimation module 3294 and / or other sub-modules of the eye tracking module 614 may refine its estimate of the CoR 3D position over time by identifying variations in its CoR estimates that have low variation (e.g., low variance or standard deviation).

[0288] As a first example, in an implementation where the CoR estimation module 3294 estimates the CoR based on the intersection of multiple different optical axes (each associated with a user looking in a different direction), the CoR estimation module 3294 may take advantage of this statistical relationship (the true CoR should have low variance) by introducing a common offset into each direction of the optical axes (e.g., shifting each axis by some uniform amount) and determining whether the offset optical axes intersect each other in an intersection that has low variation, e.g., low variance or standard deviation. This may help to correct for even slight systematic errors in calculating the optical axis directions and refine the estimated location of the CoR closer to the true CoR.

[0289] As a second example, in an implementation where the CoR estimation module 3294 estimates the CoR by moving a particular distance (e.g., the distance between the corneal center of curvature and the CoR) along the optical axis (or other axis), the system may vary, optimize, tune, or otherwise adjust the particular distance between the corneal center of curvature and the CoR over time (e.g., for a large group of eye images captured at different times) in such a manner as to reduce or minimize variability, e.g., variance and / or standard deviation, of the estimated CoR position. For example, if the CoR estimation module 3294 initially uses a particular distance value of 4.7 mm (from the corneal center of curvature along the optical axis) to obtain a CoR position estimate, but the true CoR of a given user's eye may be located 4.9 mm behind the eye's corneal center of curvature (along the optical axis), then the initial set of CoR position estimates obtained by the CoR estimation module 3294 may exhibit a relatively high amount of variability, e.g., variance or standard deviation. In response to detecting such a relatively high amount of variation (e.g., variance or standard deviation), the CoR estimation module 3294 may search for and identify one or more points along the optical axis having a lower amount of variation (e.g., variance or standard deviation), and may identify the 4.9 mm distance as having the lowest variation (e.g., variance or standard deviation), and may adjust the particular distance value utilized to 4.9 mm accordingly.

[0290] The CoR estimation module 3294 may search for alternative CoR estimates having lower variance (e.g., variance and / or standard deviation) in response to detecting that the current CoR estimate has a relatively high amount of variability (e.g., variance or standard deviation), or may search for alternative CoR estimates having lower variance (e.g., variance and / or standard deviation) necessarily after obtaining an initial CoR estimate. In some embodiments, such optimization / adjustment may occur gradually over time, while in other embodiments, such optimization / adjustment may be performed during an initial user calibration session. In embodiments where such a procedure is performed during a calibration procedure, the CoR estimation module 3294 may not initially adhere / stick to any assumed particular distance, but rather may collect sets of eye tracking data over time, perform statistical analysis on the sets of eye tracking data, and determine, based on the statistical analysis, a particular distance value that results in a CoR position estimate with the smallest possible amount of variability (e.g., variance or standard deviation) (e.g., a global minimum).

[0291] The interpupillary distance (IPD) estimation module 3296 may receive data from the CoR estimation module 3294 indicating the estimated 3D positions of the centers of rotation of the user's left and right eyes. The IPD estimation module 3296 may then estimate the user's IPD by measuring the 3D distance between the centers of rotation of the user's left and right eyes. In general, the distance between the estimated CoR of the user's left eye and the estimated CoR of the user's right eye may be approximately equal to the distance between the user's pupil centers when the user is looking at optical infinity (e.g., the optical axes of the user's eyes are approximately parallel to each other), which is a typical definition of interpupillary distance (IPD). The user's IPD may be used by various components and modules within the wearable system. As an example, the user's IPD may be provided to the alignment observer 620 and used in assessing the degree to which the wearable device is aligned with the user's eyes (e.g., whether the left and right display lenses are properly spaced according to the user's IPD). As another example, the user's IPD may be provided to a vergence-divergence motion depth estimation module 3298 and used in determining the user's vergence-divergence motion depth. The module 3296 may employ various techniques, such as those discussed in connection with the CoR estimation module 3294, to increase the accuracy of the estimated IPD. As an example, the IPD estimation module 3294 may apply filtering, averaging over time, weighted averaging including an assumed IPD distance, Kalman filtering, etc., as part of estimating the user's IPD in an accurate manner.

[0292] The vergence-divergence movement depth estimation module 3298 may receive data from various modules and sub-modules within the eye tracking module 614 (as shown in relation to FIG. 17C ). In particular, the vergence-divergence movement depth estimation module 3298 may employ data indicative of an estimated 3D position of a pupil center (e.g., as provided by module 3290 described above), one or more determined parameters of an optical axis (e.g., as provided by module 3292 described above), an estimated 3D position of a center of rotation (e.g., as provided by module 3294 described above), an estimated IPD (e.g., Euclidean distance between estimated 3D positions of centers of rotation) (e.g., as provided by module 3296 described above), and / or one or more determined parameters of an optical and / or visual axis (e.g., as provided by module 3292 and / or module 3310 described below). The vergence depth estimation module 3298 may detect or otherwise obtain a measurement of the user's vergence depth, which may be the distance from the user at which the user's eyes are focused. As an example, when the user is looking at an object three feet in front of them, the user's left and right eyes have a vergence depth of three feet, while when the user is looking at a distant scene (e.g., the optical axes of the user's eyes are approximately parallel to one another such that the distance between the user's pupil centers may be approximately equal to the distance between the rotation centers of the user's left and right eyes), the user's left and right eyes have a vergence depth of infinity. In some implementations, the vergence depth estimation module 3298 may utilize data indicating the estimated centers of the user's pupils (e.g., as provided by module 3290) to determine the 3D distance between the estimated centers of the user's pupils. The vergence-divergence depth estimation module 3298 may obtain a measurement of vergence-divergence depth by comparing such determined 3D distance between the pupil centers with an estimated IPD (e.g., a Euclidean distance between estimated 3D positions of the centers of rotation) (e.g., as shown by module 3296 described above).In addition to the 3D distance between the pupil center and the estimated IPD, the vergence movement depth estimation module 3298 may utilize known, assumed, estimated, and / or determined geometric shapes to calculate the vergence movement depth. As an example, the module 3298 may combine the 3D distance between the pupil center, the estimated IPD, and the 3D CoR position in a trigonometric calculation to estimate (e.g., determine) the user's vergence movement depth. In fact, an evaluation of such a 3D distance between the pupil centers determined relative to the estimated IPD may serve to indicate a measurement of the user's current vergence movement depth relative to optical infinity. In some examples, the vergence movement depth estimation module 3298 may receive or have access to data indicative of an estimated 3D distance between the estimated centers of the user's pupils simply for purposes of obtaining such a measurement of the vergence movement depth. In some implementations, the vergence motion depth estimation module 3298 may estimate the vergence motion depth by comparing the left and right optical axes of the user. In particular, the vergence motion depth estimation module 3298 may estimate the vergence motion depth by locating the distance from the user where the user's left and right optical axes intersect (or where the projections of the user's left and right optical axes on a plane, such as a horizontal plane, intersect). The module 3298 may utilize the user's IPD in this calculation by setting zero depth to be the depth where the user's left and right optical axes are separated by the user's IPD. In at least some implementations, the vergence motion depth estimation module 3298 may determine the vergence motion depth by triangulating eye tracking data with known or derived spatial relationships.

[0293] In some implementations, the vergence depth estimation module 3298 may estimate the user's vergence depth based on the intersection of the user's visual axes (instead of their optical axes), which may provide a more accurate indication of the distance at which the user is focused. In at least some implementations, the eye tracking module 614 may include an optical axis to visual axis mapping module 3310. As discussed in further detail in connection with FIG. 10, the user's optical and visual axes are generally not aligned. The visual axis is the axis along which a person looks, while the optical axis is defined by the person's lens and pupil center and may pass through the center of the person's retina. In particular, the user's visual axis is generally defined by the location of the user's fovea, which may be offset from the center of the user's retina, thereby resulting in different optical and visual axes. In at least some of these implementations, the eye tracking module 614 may include an optical axis to visual axis mapping module 3310. The optical axis to visual axis mapping module 3310 may correct for differences between the user's optical axis and visual axis and provide information about the user's visual axis to other components in the wearable system, such as the vergence-divergence depth estimation module 3298 and the light field rendering controller 618. In some embodiments, the module 3310 may use an assumed eye dimension 3304 that includes a typical offset between the optical axis and the visual axis of about 5.2° inward (nasally, i.e., toward the user's nose). In other words, the module 3310 may shift the user's left optical axis 5.2° nasally to the right (nasally) and the user's right optical axis 5.2° nasally to the left (nasally) to estimate the direction of the user's left and right optical axes. In other embodiments, in mapping the optical axis (e.g., as shown by module 3292 described above) to the visual axis, the module 3310 may utilize per-user calibration data 3306. As additional examples, the module 3310 may shift the user's optical axis nasally by 4.0°-6.5°, 4.5°-6.0°, 5.0°-5.4°, etc., or any range formed by any of these values.In some arrangements, module 3310 may apply the shift based at least in part on characteristics of a particular user, such as their age, gender, vision prescription, or other relevant characteristics, and / or may apply the shift based at least in part on a calibration process for the particular user (e.g., to determine the optical axis-visual axis offset for the particular user). In at least some implementations, module 3310 may also shift the origin of the left and right optical axes to correspond with the user's CoP (as determined by module 3312) instead of the user's CoR.

[0294] An optional center of perspective (CoP) estimation module 3312, when provided, may estimate the location of the user's left and right centers of perspective (CoP). The CoP may be a useful location for a wearable system, and in at least some implementations, is a location directly in front of the pupil. In at least some implementations, the CoP estimation module 3312 may estimate the location of the user's left and right centers of perspective based on the 3D location of the user's pupil center, the 3D location of the center of curvature of the user's cornea, or any such suitable data, or any combination thereof. As an example, the user's CoP may be approximately 5.01 mm in front of the center of curvature of the cornea (e.g., 5.01 mm in a direction from the center of the corneal sphere toward the cornea of ​​the eye and along the optical axis) and approximately 2.97 mm behind the outer surface of the user's cornea along the optical or visual axis. The user's center of perspective may be directly in front of its pupil center. As examples, the user's CoP may be less than about 2.0 mm from the user's pupil, less than about 1.0 mm from the user's pupil, or less than about 0.5 mm from the user's pupil, or any range between any of these values. As another example, the perspective center may correspond to a location within the anterior chamber of the eye. As other examples, the CoP may be between 1.0 mm and 2.0 mm, about 1.0 mm, 0.25 mm and 1.0 mm, 0.5 mm and 1.0 mm, or 0.25 mm and 0.5 mm from the user's pupil.

[0295] The perspective centers described herein (as potentially desirable locations for the rendering camera pinhole and anatomical locations within the user's eye) may be locations that serve to reduce and / or eliminate undesirable parallax shifts. In particular, the optical system of the user's eye is very roughly comparable to a theoretical system formed by a pinhole in front of a lens projecting onto a screen, with the pinhole, lens, and screen roughly corresponding to the user's pupil / iris, lens, and retina, respectively. Furthermore, it may be desirable for there to be little or no parallax shift when two point sources (or objects) at different distances from the user's eye are rigidly rotated around the pinhole opening (e.g., rotated along a radius of curvature equal to their respective distances from the pinhole opening). Thus, one would think that the CoP should be located at the eye's pupil center (and such a CoP may be used in some implementations). However, the human eye includes a cornea, which, in addition to the pupil lens and pinhole, imparts additional refractive power to light propagating toward the retina). Thus, the anatomical equivalent of a pinhole in the theoretical system described in this paragraph may be an area of ​​the user's eye that is located between the outer surface of the cornea of ​​the user's eye and the center of the pupil or iris of the user's eye. For example, the anatomical equivalent of a pinhole may correspond to an area within the anterior chamber of the user's eye. For various reasons discussed herein, it may be desirable to set the CoP at such a location within the anterior chamber of the user's eye.

[0296] As discussed above, the eye tracking module 614 may provide data such as estimated 3D locations of the left and right eye centers of rotation (CoR), vergence and divergence depth, left and right eye optical axes, 3D location of the user's eyes, 3D location of the user's left and right corneal centers of curvature, 3D location of the user's left and right pupil centers, 3D location of the user's left and right perspective centers, the user's IPD, etc., to other components in the wearable system, such as the light field rendering controller 618 and the alignment observer 620. The eye tracking module 614 may also include other sub-modules that detect and generate data associated with other aspects of the user's eyes. As an example, the eye tracking module 614 may include an eye blink detection module that provides a flag or other alert whenever the user blinks, and a saccade detection module that provides a flag or other alert whenever the user's eyes saccade (e.g., rapidly shift focus to another point).

[0297] Other methods of eye tracking and center of rotation determination are also possible. Thus, the eye tracking module 614 may vary. In various implementations of the eye tracking module described below, for example, an estimate of the center of rotation is determined based on multiple corneal center of curvature values. In some implementations, for example, as discussed with reference to FIGS. 17A-19, the eye tracking module 614 may estimate the eye's center of rotation by determining a convergence or intersection point among surface normal vectors, possibly fitted to multiple corneal centers of curvature for different eye poses. It should be noted that one or more features from the eye tracking module 614 described above or elsewhere herein may be included in other implementations of the eye tracking module.

[0298] Eye tracking techniques are discussed in U.S. Patent Application Publication No. 2019 / 0243558, published on August 8, 2019, and entitled "EYE CENTER OF ROTATION DETERMINATION, DEPTH PLANE SELECTION, AND RENDER CAMERA POSITIONING IN DISPLAY SYSTEMS," and International Publication No. WO2021 / 01166, published on January 21, 2021, and entitled "EYE CENTER OF ROTATION DETERMINATION WITH ONE OR MORE EYE TRACKING CAMERAS" (Attorney Reference No. MLEAP.256WO (priority to U.S. Provisional Application No. 62 / 874,867, filed July 16, 2019)), the entire disclosures of each of which are incorporated herein by reference. (Exemplary Light Injection System)

[0299] As discussed above with reference to FIG. 15, the display system may identify one or more out-coupling regions for receiving image light to be output. Additionally, as discussed above, eye posture may be determined to facilitate the determination of an appropriate out-coupling region for the selection of out-coupling image light. Once the appropriate out-coupling region or regions are determined, the display system may be configured to determine the appropriate routing of the light out-coupling region or regions. For example, functionally directing light to a particular light out-coupling region or regions may involve directing image light into an internal coupling region that is uniquely associated with those out-coupling regions.

[0300] FIG. 18 is a flow diagram of an example light directing process 3320 that may be used to direct light to a determined external coupling region of a display. In block 3322, the display system may determine an internal coupling region for directing light onto the display. For example, the internal coupling region may include an internal coupling region associated with a desired rendering location on the display. The desired rendering location may be determined based on a determination process such as described with reference to FIG. 16. In some examples, the internal coupling region may be an area, group, array, or other combination of internal coupling optical features, such as an internal coupling grid. As illustrated in FIG. 19, the internal coupling region of the display may include an array of internal coupling features arranged along a portion of the display. In block 3322, the display system may determine to direct light to the internal coupling region such that the light is directed to the appropriate associated external coupling region to form at least a portion of a perceived image on the display.

[0301] In block 3324, the display system may determine an image for displaying to the user. The image may include a representation of virtual content to be displayed in the user's environment, and the image may include a portion of the virtual content or all of the virtual content. For example, the display system may receive an indication to display a tree. The display system may determine a representation of a tree for projecting into the determined interior bounded region or a portion of a tree for projecting into the determined interior bounded region. In some embodiments, the display system may split an image or representation of a virtual object that may span across multiple exterior bounded regions of the viewing area of ​​the display. In such a case, to display the full effect of the virtual object, the display system may split the image such that light projected onto a portion of the image in a first region of the display contains the portion of the image associated with that region during rendering. In some embodiments, the image may contain portions of the representation of the virtual object that overlap by an amount to prevent gaps in the rendering when displaying a large object across a region of the display.

[0302] In block 3326, the display system may transmit instructions to direct light to the internal coupling region. As discussed above, the directed light may include image information for forming an image for display from the external coupling region of the display associated with that internal coupling region. The display system may utilize one or more light injection systems to direct light to the internal coupling region. For example, as illustrated in FIG. 19, the display system may include a controller 3402, a light injection system 3404, a waveguide 3412, and a camera 3408. The controller 3402 may communicate instructions to the light injection system 3404 to direct or inject light 3410 into a selected internal coupling region, such as internal coupling region 3414A, 3414B, or 3414C on the waveguide 3412. As discussed above with reference to FIGS. 16-17C, the display system may determine which in-coupling region 3414A, 3414B, 3414C or in-coupling optical element 3416A, 3416B, 3416C associated with the in-coupling region to inject light into based on, for example, the user's eye posture. The user's eye posture may be determined by the display system using images from one or more cameras 3408 configured to image at least one eye of the user. The injected light may propagate through one or more waveguides associated with the display toward the associated out-coupling region 3418A, 3418B, 3418C. One or more out-coupling optical elements in the out-coupling region 3418A, 3418B, 3418C may output light toward the user's eye 3406. It should be understood that the internal bond regions 3414A, 3414B, 3414C may correspond to any of the internal bond regions identified by reference numbers 1005, 700, 710, and 720 and various subscripts (see, for example, Figures 11A and 14B).

[0303] The controller 3402 may include one or more software engines to implement the processes and functions described herein. The software engines may include programmed instructions to implement the processes as discussed herein (and illustrated in the flow charts) to direct the light injection system to inject light towards an area of ​​the display. The engines may be executed by one or more hardware processors associated with the display system. The programming instructions may be stored in a memory associated with the display system. The programming instructions may be implemented in C, C++, JAVA, or any other suitable programming language. In some implementations, some or all of the portions of the controller 3402, including the engines, may be implemented in application specific circuitry such as ASICs and FPGAs. Some aspects of the functionality of the controller 3402 may be executed remotely on a server via a network. Thus, the controller 3402 may be implemented using hardware components (e.g., controller 560, processing module 140 and / or processing module 150) described above with reference to Figures 6 and 9D.

[0304] The light injection system may be any suitable system for selectively directing light towards a desired region. For example, as illustrated in Figs. 20A-20D, the light injection system may include a movable injection mechanism, such as a scanning fiber injector. In another embodiment, as illustrated in Figs. 21A-21D, the light injection system may include one or more movable mirrors to direct light. Additionally or alternatively, the light injection system may utilize one or more stationary injection systems, such as those that form images for different incoupling regions at different locations of the SLM as described in detail with reference to Fig. 22. However, although details of exemplary light injection systems may be discussed, the display system may utilize any number or combination of light injection systems to direct light to determined incoupling regions. Exemplary Mechanically Actuated Light Injection System

[0305] The light launch system 3404 (FIG. 19) may take the form of a movable launch system in some implementations. The movable launch system may include one or more components configured to physically move optical components to direct light toward a desired location, such as an internal coupling region 3414A, 3414B, 3414C, on the waveguide 3412. FIGS. 20A-20D and 21A-21B illustrate two exemplary movable launch systems.

[0306] 20A-20D illustrate an implementation of an example mobile launch system 3500 including at least one scanning fiber launcher 3527. It should be understood that the mobile launch system 3500 may correspond to the light launch system 3404 (FIG. 19). The scanning fiber launcher 3527 may include at least one light emitter 3528 and at least one actuator 3540 that moves the fiber 3542. The light 3501 from the end of the fiber 3542 may propagate through the optics 3534 toward the in-coupling region 3510A' or 3510B' in the waveguide 3526'. In some embodiments, as illustrated in FIG. 20A, the optics 3534 may be a collimating optic configured to receive light that radiates out from the fiber 3542 and collimate the light before it propagates to the in-coupling region 3510A' or 3510B'.

[0307] The collimating optics may take various forms and may include one or more lens structures. In some embodiments, as illustrated in FIG. 20B, the optics 3534 may include a lenticular lens with multiple lenses 3534L′, 3534L″ (e.g., a lenslet array). Each of the multiple lenses may be configured to provide collimated light to an associated in-coupling region 3510A′ or 3510B′. In some embodiments, as illustrated in FIG. 20C, the optics 3534 may include a collimating lens structure 3534C for collimating the incident light and a projection lens structure 3534P for propagating the collimated light to the in-coupling region 3510A′ or 3510B′. It should be understood that more generally, the optics 3534 may include a combination of various lens structures to perform the function of providing collimated light to multiple in-coupling regions, such as the in-coupling region 3510A′ or 3510B′. In some examples, as shown in FIG. 20D, the projection optics 3534 may include a collimating lens arrangement 3534C and a projection lens arrangement 3534P comprising a lenticular lens comprising a convex lens 3534P' and multiple lenses 3534L', 3534L''. It should be understood that other combinations of lenses are also contemplated.

[0308] 20A-20D, the actuator 3540 may move the fiber 3542 at a known speed along a predetermined path (e.g., a circular path), such that the processing module 3638 may be configured to synchronize the propagation of light out of the end of the fiber 3542 with the movement of the fiber 3542 such that the image light propagates out of the fiber 3542 at a desired light output location, and thus is synchronized with the image to be displayed.

[0309] In some implementations, the light source 3528 may be replaced with a virtual light source formed on an image plane of an optical projection system. The optical projection system may include an actuator capable of scanning a beam of light across an area on the image plane corresponding to the virtual light source. To mimic the ability to activate discrete light-emitting areas of the light source 3528 as discussed herein, the output of light by the projection system is synchronized with the movement of the actuator to output light to desired locations on the image plane at a particular time. Preferably, the rate at which the actuator is capable of scanning the beam of light across the image plane is high enough that all desired light output locations on the image plane can be accessed during the time frame during which any given intra-pupillary image is displayed. For example, during the amount of time during which a particular image is displayed, the actuator is preferably capable of scanning the beam of light across the area of ​​the image plane corresponding to the virtual 2D light source at least once, and preferably multiple times.

[0310] 21A and 21B illustrate another example movable input system 3600 that includes at least one scanning mirror system for directing light propagation to different locations. Light input system 3626 may include an image source 3628 that may output image light, and mirrors 3630 and 3632 that are moved by actuators 3631 and 3633, respectively. An example of image source 3628 includes one or more light sources and a spatial light modulator that encodes image information into light that passes from the light source through the spatial light modulator to mirror 3632.

[0311] As shown, light 3501 may be transmitted from an image source 3628 to a mirror 3632, which reflects the light to a mirror 3630, which then reflects the light propagating through the projection optics 3634 towards the internal coupling optical regions 3510A' or 3510B' of the waveguide 3526'. The mirrors 3630 and 3632 may be part of a dual-axis galvanometer, and the actuators 3631 and 3633 rotate the mirrors along different axes, e.g., orthogonal axes, thereby allowing light to be directed to an area defined along the two axes of the waveguide 3526'. In some implementations, the actuators 3631, 3633 may be motors. The projection optics 3634 may be a linear transfer lens, such as an F-theta (F-θ or F-tan θ) lens, and may be configured to project light onto the waveguide 3526′ at an in-coupling optical region, such as 3510A′ or 3510B′. In some implementations, the light injection system 3626 may also include a collimating lens 3636 to collimate the light emitted by the light emitter 3628 before the light reaches the mirror 3632. In some embodiments, as illustrated in FIG. 21A , the projection optics 3634 may include various lens structures. In some embodiments, as illustrated in FIG. 21B , the projection optics 3634 may include a convex lens structure 3634P′ and a lenticular lens with multiple lenses 3634L′, 3634L″, each configured to direct the collimated light to an associated in-coupling optical region, such as 3510A′ or 3510B′.

[0312] 21A and 21B, the light injection system 3626 preferably also includes or communicates with a processing module 3638 that controls the output of light from the light emitter 3628 and synchronizes it with the movement of the actuators 3631, 3633 and the image to be formed. For example, the processing module 3638 may coordinate the emission of light from the image source 3628 with the movement of the mirrors 3632, 3630. In some implementations, the mirrors 3632, 3630 are continuously rotated or pivoted back and forth by the actuators 3631, 3633 on the axis on which the mirrors are designed to move. The emission of light (e.g., pulses of light) by the image source 3628 is timed with this movement such that the light is directed to a desired location on the waveguide 3526' at a given moment, with this location and time also being determined based on the image to be displayed (e.g., the incoupling region is timed with the display of the image for that particular incoupling region). In some implementations, light emission from the image source 3628 is controlled by switching the image source 3628 between an on state and an off state (e.g., by supplying or not supplying power to a light emitter, respectively). In some other implementations, light emission from the image source 3628 may be mechanically controlled using a physical switch that selectively allows or blocks light from reaching the waveguide 3526'.

[0313] In some other implementations, rather than two mirrors 3632 and 3630, the movable light injection system 3600 may include only a single mirror configured to direct light along a single axis. Such a configuration may be utilized in an arrangement, for example, where internal coupling regions such as 3510A' or 3510B' are arranged in a line along a single axis.

[0314] Several mobile inserter techniques are discussed in U.S. Patent Application Publication No. 2018 / 0113311, published April 26, 2018 and entitled “SYSTEM AND METHOD FOR PRESENTING IMAGE CONTENT ON MULIPLE DEPTH PLANES BY PROVIDING MULTIPLE INTRA-PUPIL PARALLAX VIEWS,” the entire disclosure of which is incorporated herein by reference. Example Electronically Switchable Light Output Without Mechanical Actuation

[0315] The light launch system 3404 may include a launch system in which the location of the output light is switched electronically without mechanical actuation. The stationary launch system may include one or more components configured to selectively emit light to direct the light toward a desired location, such as the internal coupling regions 3414A, 3414B, 3414C on the waveguide 3412.

[0316] FIG. 22 illustrates an example stationary injection system 3700 including a spatial light modulator (SLM) 3736 configured to project light 3501 onto a waveguide 3526' toward one or more in-coupling optical regions 3710A', 3710B'. The stationary injection system 3700 may include a light emitter 3728 and a spatial light modulator (SLM) 3736. Examples of the light emitter 3528 include LEDs and lasers. In some implementations, a fiber optic cable may transmit the light from a remotely located light emitter. As shown, the light 3501 may be propagated from the light emitter 3728 to the SLM 3736, which modulates the light and propagates it through an optical system 3734 toward the in-coupling optical region 3710A' or 3710B' in the waveguide 3526'. In some implementations, the SLM 3736 may be configured to modulate light transmitted through the SLM. In some other implementations, the SLM 3736 may be configured to reflect and modulate light. Examples of SLMs include liquid crystal display panels, DLP mirror arrays, LCoS, etc. The optical system 3734 may be a linear transmission lens, such as an F-theta (F-θ or F-tan θ) lens, and may be configured to focus the light onto the waveguide 3526′ into an internal coupling optical region, such as 3710A′ or 3710B′. However, other configurations of the optical system 3734, such as a lens system, including some combination of collimating lenses, lenticular lenses, or other lens structures, are also contemplated.

[0317] The SLM 3736 may comprise a panel display, which may include an array of light emitters, such as LEDs or lasers. To select an incoupling optical region, such as 3710A' or 3710B', for propagation, the controller 3738 may communicate with the light injection system 3700 and cause the SLM 3736 to activate a pixel, array, or group of pixels within the SLM 3736 that may be associated with the desired incoupling optical region or regions. In some implementations, different sections of the SLM may be utilized to form different images for different associated ones of the incoupling regions 3710A', 3710B'. In some implementations, the size of the groups of activated light emitting pixels on the light source SLM 1020 may provide smaller or larger images. In some other implementations, the size of the light emitting area on the light source SLM 3736 may be modified to control the focal depth of the display system.

[0318] Several mobile putter techniques are discussed in International Patent Publication No. WO2019 / 173158, published September 12, 2019, and entitled "DISPLAY SYSTEM WITH LOW-LATENCY PUPIL TRACKER," the entire disclosure of which is incorporated herein by reference. (Example Depth Plane Projection)

[0319] Some implementations of display devices, such as those described above, may be configured to adjust the wavefront divergence of light (including light for image information projected from the display system and incident light from objects in the surrounding real world) by adjusting the focal length of a variable focus lens element included in the augmented reality system. As discussed above, the augmented reality system may comprise a display device that may include a plurality of stacked waveguides (e.g., corresponding to the plurality or set 660 of stacked waveguides in FIGS. 9A and 9B or corresponding to the stacked waveguide assembly 260 in FIG. 6) that project light toward the eye of a user or viewer (e.g., viewer or user 90 in FIG. 2). In some other implementations, the display device may include only a single waveguide. As a result, although a plurality of waveguides is referenced in various portions of this disclosure, it should be understood that the plurality of waveguides may be replaced by a single waveguide.

[0320] As discussed herein, the light projected from the waveguide may be used to provide virtual or augmented reality image information to a viewer. The light may be projected such that a user perceives the light as originating from one or more different depths or distances from the viewer. The display device may be optically transparent such that a user may see real-world objects in the surrounding environment through the display device. In some implementations, the waveguide may be configured to have a fixed optical power. To provide the appearance that the projected light originates from different depths, the waveguide may be configured to output a diverging beam of light, with different amounts of divergence corresponding to different depth planes.

[0321] To provide a multi-dimensional sensation to the displayed virtual object, the display system may display images on multiple depth planes. For an array of internal coupling elements, there are several ways to project images on multiple depth planes. These include split-pupil systems as illustrated in FIG. 23, variable focus lens systems as illustrated in FIG. 24, and systems configured to approximate a continuous wavefront using multiple intra-pupillary images as illustrated in FIG. 25C and 25D. (Example Separate Pupil Depth Plane Projection)

[0322] In some embodiments, depth plane projection may be accomplished by projecting an image toward an incoupling optical element in a waveguide stack as described above with reference to Figures 9A-9C. In the case of an array of incoupling regions in a waveguide, depth plane projection may be accomplished, for example, by having multiple incoupling optical regions per incoupling element that correspond to a particular depth plane.

[0323] FIG. 23 illustrates a top-down view of an in-coupling region 3800 that may include multiple in-coupling optical elements 3810A, 3810B, 3810C. A light emitter (not shown) may emit light at a wavelength corresponding to one of multiple colors toward the in-coupling elements 3810A, 3810B, 3810C. The in-coupling optical elements 3810A, 3810B, 3810C may be arranged to be spaced apart similarly to the light emitters. For example, each one of the in-coupling optical elements 3810A, 3810B, 3810C may be in the direct light path of an associated one of the light emitters. Multiple in-coupling optical elements, such as elements 3810A, 3810B, 3810C, may be arranged in a waveguide stack to provide a multi-depth plane projection for an image that is projected toward the region 3800 containing the in-coupling optical elements.

[0324] In the illustrated embodiment, there are nine internal coupling optical elements 3810. The nine internal coupling optical elements 3810 may be configured to project a single image having multiple colors on multiple depth planes. The illustrated nine internal coupling optical elements 3810 may include, for example, three elements configured to emit light of a first color (e.g., red), three elements configured to emit light of a second color (e.g., green), and three elements configured to emit light of a third color (e.g., blue). However, other numbers of internal coupling optical elements with other groupings are also possible. Each grouping may include internal coupling optical elements of different colors (e.g., each grouping may have one internal coupling optical element for the first color, one internal coupling optical element for the second color, and one internal coupling optical element for the third color), and each grouping may be configured to form an image on a particular depth plane. For example, the incoupling optical elements 3810 form three groups, with each group projecting an image onto an associated one of the three depth planes, however, other numbers, arrangements and configurations of incoupling optical elements are also possible, such as six incoupling optical elements configured to project light of three primary colors onto two depth planes, twelve incoupling optical elements configured to project light of four colors onto three depth planes, etc.

[0325] In some examples, the incoupling regions may be configured to project light in multiple colors onto multiple depth planes using temporal multiplexing. For example, an incoupling element may include multiple incoupling regions configured to project light onto multiple depth planes. One or more light emitters may be coupled to the incoupling element and project light of a specific color toward the incoupling optical element at a specific time. If the time between color projections is fast enough, the resulting perceived image may be an image with all colors projected toward the incoupling optical element. (Example variable focus lens configuration)

[0326] In some embodiments, depth plane projection may be performed using a variable focus lens system. Figure 24 illustrates an example variable focus lens system 3900 that may be used to perform depth plane projection.

[0327] Referring to FIG. 24, in some implementations, a first variable focus lens element may be provided between the waveguide and the viewer's eye to provide an appropriate adjustment to the wavefront of the light output by the waveguide, allowing the light to be properly focused by the viewer's eye. However, this first lens element is also in the path of the light propagating from the surrounding environment to the viewer's eye. As a result, the first lens element may modify the wavefront of the light from the surrounding environment, thereby causing aberrations in the viewer's view of the world. To correct such aberrations, a second variable focus lens element may be disposed on the opposite side of the first variable focus lens element of the multiple stacked waveguides, i.e., the second variable focus lens element may be between the multiple stacked waveguides and the surrounding real world, and may adjust the wavefront of the light from real world objects in the surrounding environment. The second variable focus lens element may be configured to compensate for the aberrations caused by the first variable focus lens element. In some implementations, the second variable focus lens may also be configured to compensate for the aberrations caused by the waveguide.

[0328] In some implementations, the focus of the second variable focus lens element may be the inverse or opposite of the focus of the first variable focus lens element. For example, if the first variable focus lens element has a positive refractive power, then the second variable focus lens element may have a negative refractive power, which may be of similar magnitude. In some other implementations, the refractive power of the second lens element may be opposite and of similar magnitude to the aggregate refractive power of the first lens element and the waveguide, to compensate for both the refractive power of the first variable focus lens element and the refractive power of the intervening waveguide.

[0329] In some other implementations, the waveguide may not have a refractive power (e.g., the waveguide may be configured to output collimated light), and the first variable focus lens element may be configured to modify the wavefront of the light emitted from the waveguide to provide an appropriate amount of divergence for the image information to be interpreted by the viewer as being on a particular depth plane. It should be understood that the appropriate amount of divergence may vary for different viewers, as the refractive power for placing the image information on a particular depth plane will be adjusted by a particular differential and will take into account the viewer's optical prescription for that depth plane. In such implementations, the waveguide stack between the first variable focus lens element and the second variable focus lens element may simply be formed by a single waveguide.

[0330] It should be understood that first and second variable focus lens elements may be provided for one of the viewer's eyes, and third and fourth variable focus lens elements, similar to the first and second variable focus lens elements, respectively, may be provided for the viewer's other eye.

[0331] 24 shows a schematic diagram of an example display system (e.g., an augmented reality display system) having a variable focus lens element and a waveguide stack. It should be understood that the display system 3910 may correspond to the display system 250 (FIG. 6). The first variable focus lens element 3907a and the second variable focus lens element 3907b are disposed on opposite sides of the waveguide stack 3905, and the third variable focus lens element 3908a and the fourth variable focus lens element 3908b are disposed on opposite sides of the waveguide stack 3906.

[0332] The various illustrated waveguides 3905a, 3905b, 3906a, 3906b may have properties and / or characteristics similar to individual ones of the waveguides 270, 280, 290, 300, 310 of Figure 6 and / or the waveguides 670, 680, and 690 of Figures 9A and 9B. The waveguide stacks 3905, 3906 may have properties and / or characteristics similar to the stacked waveguides of the plurality or set 660 of Figures 9A and 9B or the stacked waveguide assembly 260 of Figure 6. In some implementations, the waveguides 3905a, 3905b, 3906a, 3906b may include optical elements, such as diffractive optical elements, that provide optical power to the waveguides, e.g., fixed optical power. For example, one or more of these waveguides may have an optical power in the range of 0 diopters to about 5.0 diopters, about 0.5 diopters to about 4.5 diopters, about 1.0 diopters to about 4.0 diopters, about 1.5 diopters to about 3.5 diopters, about 2.0 diopters to about 3.0 diopters, or any value within these ranges or subranges. As another example, in a particular implementation, the waveguides may each have an optical power of 1.5 diopters.

[0333] As discussed above, light providing image information (e.g., virtual content) from light source 3903 or 3904 may be launched into waveguide 3905a or 3906a, respectively, such that the light propagates through each of those waveguides by total internal reflection. The propagating light may be projected out of waveguide 3905a (or waveguide 3905b) toward the user's eye 3901 by an external coupling element (e.g., corresponding to external coupling elements 800, 810, 839 in FIGS. 9A and 9B). In some implementations, light sources 3903, 3904 may be fiber scanning devices (FSDs) that utilize movable fibers to create 2D image patterns as disclosed herein. The FSDs may create 2D image patterns by projecting light in various patterns, such as, for example, raster scan, helical scan, Lissajous, etc. In some other implementations, light source 3903a (and / or 3903b) may be an image projection system, e.g., in which a complete image is projected onto a waveguide, as also disclosed herein. It should be understood that light from light source 3903a (and / or 3903b) may be injected into the waveguide stack 3905 through an edge of the waveguide or through a major surface of the waveguide. If the waveguide stack includes multiple waveguides, light source 3903 and / or 3904 may be configured to inject light into multiple ones of these waveguides, or additional light sources may be provided, e.g., one light source per waveguide.

[0334] A first variable focus lens element 3907a may be disposed between the waveguide stack 3905 and the user's eye 3901, and a second variable focus lens element 3907b may be disposed between the waveguide stack 3905 and the real world surrounding the user. It should be understood that eye 3901 may correspond to the viewer's eye 210 of FIG. 6. Similarly, a third variable focus lens element 3908a may be disposed between the waveguide stack 3906 and the user's eye 3902, and a second variable focus lens element 3908b may be disposed between the waveguide stack 3906 and the real world surrounding the user.

[0335] In some implementations, the first and second variable-focus lens elements 3907a and 3907b and the third and fourth variable-focus lens elements 3908a and 3908b may be adaptive optical elements. The adaptive optical elements may be dynamically altered, for example, by applying an electrical signal thereto to change the shape of a wavefront incident thereon. In some implementations, the adaptive optical elements may comprise transmissive optical elements such as dynamic lenses (e.g., liquid crystal lenses, electroactive lenses, conventional refractive lenses with movable elements, mechanical deformation-based lenses, electrowetting lenses, elastomeric lenses, or multiple fluids with different refractive indices). By altering the shape, refractive index, or other properties of the adaptive optical system, the wavefront incident thereon may be altered, for example, altering the focusing of light by the viewer's eye, as described herein.

[0336] In some implementations, the variable focus lens elements 3907a, 3907b, 3908a, 3908b may comprise a layer of liquid crystal sandwiched between two substrates. The substrates may comprise an optically transmissive material, such as, for example, glass, plastic, acrylic, etc. In some implementations, the substrates may be flat. In some implementations, the substrates may have curved regions such that a portion of the substrate may have a fixed optical power.

[0337] In some implementations, the refractive power of the variable focus lens elements 3907a, 3907b, 3908a, 3908b may be varied by adjusting an electrical signal (e.g., current and / or voltage) applied to the liquid crystal layer, for example, via one or more thin film transistors (TFTs) and / or electrodes integrated with the liquid crystal layer and / or substrate. It should be understood that the orientation of the liquid crystal species in the liquid crystal layer determines the refractive index of the layer. The applied electrical signal sets the orientation of the liquid crystal species, thereby allowing the refractive index of the liquid crystal layer to be varied as desired by modifying the applied electrical signal. In some implementations, the refractive power of the variable focus lens elements 3907a, 3907b, 3908a, 3908b may be varied by approximately ±5.0 diopters (e.g., from approximately -4.0 diopters to +4.0 diopters, from approximately -3.5 diopters to approximately +3.5 diopters, from approximately -3.0 diopters to approximately +3.0 diopters, from approximately -2.0 diopters to approximately +2.0 diopters, from approximately -1.5 diopters to approximately +1.5 diopters (including values ​​within any of these ranges or subranges)).

[0338] Advantageously, the variable focus lens elements 3907a, 3907b, 3908a, 3908b may have wide apertures that are substantially matched to the apertures of the waveguides of their respective associated waveguide stacks 3905, 3906. In some implementations, the apertures of the variable focus lens elements 3907a, 3907b, 3908a, 3908b may be substantially equal (e.g., within about ±39%, about ±15%, or about ±10%) to the surface areas of the waveguides of the waveguide stacks 3905, 3906. As a result, the areas over which the variable focus lens elements 3907a, 3907b, 3908a, 3908b and the waveguide stacks 3905, 2396 transmit light to the associated eyes 3901, 3902 may be substantially equal.

[0339] 24, the first and third variable focus lens elements 3907a, 3908a may each vary their refractive power to adjust the wavefront of light projected from the waveguides of the waveguide stacks 3905, 3906, respectively, to properly focus that light onto the retina of the eyes 3901, 3902, respectively. As described herein, the first and third variable focus lens elements 3907a, 3908a may introduce aberrations into the wavefront of incident light from an object 3909 in the surrounding environment, thereby reducing the optical quality of the real-world object 3909 viewed through the first variable focus lens element 3907a. The second and fourth variable focus lens elements 3907b, 3908b may advantageously compensate for aberrations introduced by the first and third variable focus lens elements 3907a, 3908a and any waveguides, respectively, when viewing the object 3909. In some implementations, the second and fourth variable focus lens elements 3907b, 3908b may be configured to provide an opposite refractive power to that provided by the first and third variable focus lens elements 3907a, 3908a and associated waveguide stacks 3905, 3906, respectively. In some implementations, the magnitude of the opposite refractive power is such that the net refractive power of the display system 3910, 3901, 3902, per eye, is equal to the optical prescription for the eye in the depth plane towards which the eye is verging. The optical power provided by the first and second variable focus lens elements 3907a and 3907b may be varied and controlled by an electronic hardware control system 3911. In some implementations, the electronic hardware control system 3911 may correspond to the local processing and data module 140 and / or the remote processing module 150 of FIG.

[0340] In some implementations, the augmented reality display system 3910 may be configured to determine the convergence and divergence of the user's eyes. The refractive power of the first and second variable focus lens elements 3907a, 3907b may be set based on the convergence and divergence points of the eyes 3901, 3902. The refractive power of the third and fourth variable focus lens elements 3908a, 3908b may also be set based on this convergence and divergence point. It should be understood that the convergence and divergence point is a point in space where the lines of sight of the eyes 3901, 3902 converge and may correspond to the physiological accommodation targets of those eyes. In some implementations, the distance the point is away from the eyes 3901, 3902 may be calculated, for example, based on a known amount of separation between the eyes 3901, 3902 and the angle made by each eye. Once the distance is calculated, an appropriate correction for the viewer for that distance may be determined. For example, the display system 3910 may be programmed with one or more optical prescriptions. In some implementations, the optical prescriptions may be stored in the local processing and data module 140 and / or the remote data repository 160. The distance between the eyes 3901, 3902 and the convergence-divergence points may be matched with an appropriate correction for that distance, and the variable focus lens elements 3907a, 3907b, 3908a, 3908b may be adjusted to provide the correction. In some implementations, the eyes 3901, 3902 may have different predefined corrections, and as a result, the pair of variable focus lens elements 3907a, 3907b and 3908a, 3908b may provide different refractive powers.

[0341] Advantageously, the variable focus lens elements 3907a, 3907b, 3908a, 3908b provide a large number of possible corrections since their refractive power can be adjusted as desired, for example, by application of different voltages. In some implementations, the total number of corrections per eye may be 1, 2, 3, 4, or more. In some implementations, the total number of corrections per eye may be equal to the number of depth planes on which the display system 3910 is configured to display image information. It should be understood that these corrections may correspond to optical prescriptions, which may be determined for objects at various distances from the eyes 3901, 3902. For example, four prescriptions may be obtained by determining corrections for refractive errors at four progressively more distant distances from the eyes 3901, 3902 (e.g., near, medium near, medium far, and far). In some implementations, the number of possible corrections for viewing the image content output by the waveguide stack 3905 may be different from the number of possible corrections when viewing an object 3909 in the surrounding environment.

[0342] In some implementations, the focus or refractive power of the variable focus lens elements 3907a, 3907b, 3908a, 3908b, respectively, may be set based on the determined convergence-divergence movement of the user's eyes 3901, 3904. For example, the refractive power of the first and second variable focus lens elements 3907a and 3907b may be varied based on the convergence-divergence movement of the user's eyes 3901 without specific reference to the refractive power of the other lens elements.

[0343] In some implementations, one of the first and second variable focus lens elements 3907a, 3907b or one of the third and fourth variable focus elements 3908a, 3908b may be designated as a master and the other of the first and second variable focus lens elements 3907a, 3907b or the third and fourth variable focus elements 3908a, 3908b may be designated as a slave. The variable focus lens element designated as the slave may be configured to track the master variable focus lens element. In some other implementations, the second and fourth variable focus lens elements 3907b, 3908b may be tracked to the first and third variable focus lens elements 3907a, 3908a, and the focus of the first and third variable focus lens elements 3907a, 3908a may be set based on the determined convergence-divergence movement points of the user's eyes 3901, 3902. For example, if waveguide 3905a (and / or waveguide 3905b) has a refractive power of approximately 1.5 diopters and the user is convergent at 2.0 diopters, the first variable-focus lens element 3907a may have a refractive power of +0.5 diopters and the second variable-focus lens element 3907b may have a refractive power of -0.5 diopters.

[0344] The refractive power of the variable focus lens elements 3907a, 3907b, 3908a, 3908b may be varied in real time, preferably at a rate equal to or exceeding the rate at which the human eye changes its accommodation state. Preferably, the first and second variable focus lens elements may change their refractive power before the human eye changes its accommodation state, so that the user does not incur a delay in receiving the appropriate correction for a given convergence-divergence motion point. In some implementations, the first and second variable focus lens elements may change their refractive power in less than about 300 ms, less than about 275 ms, or less than about 250 ms. The electronic hardware control system 3911 may drive the variable focus lens elements 3907a, 3907b, 3908a, 3908b such that the refractive powers of the variable focus lens elements 3907a, 3907b, 3908a, 3908b may be varied simultaneously.

[0345] Variable focus lens techniques are discussed in U.S. Patent Application Publication No. 2017 / 0293145, published October 12, 2017, and entitled "AUGMENTED REALITY SYSTEMS AND METHODS WITH VARIABLE FOCUS LENS ELEMENTS," the entire disclosure of which is incorporated herein by reference. Exemplary Wavefront Approximation Using Multiple Intrapupil Images

[0346] It has been found that a continuous wavefront, such as wavefront 4000 of Figure 25A, can be approximated using multiple wavefronts. In some embodiments, depth plane selection can be accomplished by approximating a continuous wavefront at one or more desired depth planes using multiple discrete intrapupillary images directed into the eye within the flicker fusion threshold.

[0347] 25A, pre-accommodation and post-accommodation states of the eye 210 in response to receiving a continuous input wavefront 4000 are illustrated. Illustration a) illustrates the pre-accommodation state before the visual system focuses the wavefront 4000 onto the retina 211. It should be noted that the focal point 212 is not on the retina 211. For example, the focal point 212 may be in front of the retina 211, as shown. Illustration b) illustrates the post-accommodation state after the human visual system relaxes the pupil musculature of the viewer's eye 210 and focuses the wavefront 4000 onto the retina 211. As shown, the focal point 212 may be on the retina 211.

[0348] FIG. 25B illustrates pre-accommodation and post-accommodation states of the eye 210 in response to receiving a piecewise approximation of the continuous wavefront 4000 of FIG. 25A. Illustration a) of FIG. 25B illustrates the pre-accommodation state of the eye 210, and illustration b) illustrates the post-accommodation state. The approximation may be formed using multiple constituent wavefronts 1010a, 1010b, and 1010c, each associated with a separate beam of light. As used herein, reference numerals 1010a, 1010b, and 1010c may refer to both a beam of light and the associated wavefront of that beam of light. In some implementations, the constituent wavefronts 1010a and 1010b may be planar wavefronts, such as those formed by a collimated beam of light. As shown in illustration b), the wavefront approximation 1010 formed by constituent wavefronts 1010a and 1010b is focused by eye 210 onto retina 211 with a focal point 212 on retina 211. Advantageously, the pre- and post-accommodation conditions are similar to those produced by the continuous wavefront 4000 shown in FIG.

[0349] It should be understood that the continuous divergent wavefront can be approximated using an optical projection system that outputs multiple parallax-dissimilar intrapupillary images into the eye. FIG. 25C illustrates the eye accommodating to a divergent wavefront emanating from a finite focal distance virtual image provided by a projection system. The system includes a spatial light modulator 4018 and a projection optics 1020 with a focal length "F" and an external stop. An image may be formed by the spatial light modulator 1018, and light from the spatial light modulator 4018 containing image information may be directed to the eye 210 through the projection optics 4020. The spacing between the spatial light modulator 4018 and the projection optics 4020 (less than F) may be chosen such that a divergent wavefront 4000 is output toward the eye 210. As discussed above with respect to FIG. 25A, the eye 210 may then focus the wavefront 4000 onto the retina 211.

[0350] 25C, an example of a display system 4001 is illustrated that includes a projection system 4003 for forming the diverging wavefront approximation 4010 of FIG. 25B. The projection system 4003 includes a light source 4026 configured to output light 4010a′ and 4010b′ to a spatial light modulator 4018, which modulates the light and forms images showing slightly different parallax views of the same object or scene. The modulated light with the image information then propagates through and is output by the relay / projection optics 4020 as light beams 4010a and 4010b into the eye 210. The projection system 4003 may also include a lens structure 4014, which may be configured to convert spatial differences in the emission of light 4010a′ and 4010b′ into angular differences in the propagation of that light to the spatial light modulator 4018. The projection system 4003 may further include a polarizing beam splitter 4016 configured to 1) direct light from the light source 4026 to the spatial light modulator 4018 and 2) allow modulated light from the spatial light modulator 4018 to propagate back to the relay / projection optics 4020 through the beam splitter 4016. In some implementations, the display system 4001 may include an eye tracking device 4022, e.g., a camera, configured to monitor the gaze of the eye. Such monitoring may be used to determine the direction in which the viewer is looking, which may be used to select appropriate image content for that direction and for eye pose determination, as discussed herein. Preferably, the eye tracking device 4022 tracks both of the viewer's eyes, or each eye includes its own associated eye tracking device. As a result, the vergence and divergence movements of the viewer's eyes may be tracked and the convergence points of the eyes may be determined to determine the direction and distance at which the eyes are pointed.

[0351] It should be understood that the light 4010a' and 4010b' may be output by the light source 4026 at different times, as discussed herein, the spatial light modulator 4018 may form different parallax views using the light 4010a' and 4010b' at different times, and the resulting light beams 4010a and 4010b may be injected into the eye 210 at different times.

[0352] 25C, the light source 4026 may be a 2D light source having a plurality of selectively activated light output locations disposed substantially on a plane. In some implementations, the selectively activated light output locations may be selectively activated light emitting regions. For example, the light source 4026 may be a light emitting diode (LED) array, or a spatial light modulator (e.g., a digital micromirror device such as a digital light processing (DLP) device, an LCOS device, etc.) that contains an array of discrete units or light emitters that output light. Examples of LED arrays include organic light emitting diode (OLED) arrays and inorganic light emitting diode (ILED) arrays, each of which may be part of a microdisplay. In some implementations, individual light emitting diodes and / or light modulators within the light source 4026 may constitute a light emitting region. In some other implementations, a group of light emitting diodes and / or light modulators may form a light emitting region. In such implementations, there may be some overlap between the light emitting diodes and / or light modulators of different light emitting regions, but the regions may be considered distinctly different because the overlap is not complete.

[0353] In some other implementations, the light source 4026 may be configured to focus light onto an image plane, in effect providing a virtual 2D light source at that image plane. Different locations on the image plane may be considered different light output locations, which may be activated by steering the light from the light emitter using actuated mirrors or fiber scanners to direct the light through those locations on the image plane. Further details regarding such virtual 2D light sources are provided in the discussion of Figures 19 and 20 below.

[0354] In some implementations, an example of the spatial light modulator 4018 includes a liquid crystal on silicon (LCOS) panel. As another example, in some other implementations, the spatial light modulator 4018 may comprise a transmissive liquid crystal panel or a MEMS device such as a DLP.

[0355] 25C, the display system 4001 may also include a control system 4024 for determining the timing and type of image content provided by the display system. In some implementations, the control system 4024 comprises one or more hardware processors with memory storing programs for controlling the display system 4001. For example, the system 4024 may be configured to control the activation of light emitting regions of the light source 4026, the actuation of individual pixel elements of the spatial light modulator 4018, and / or the interpretation and reaction of the display system 4001 to data received from the eye tracking device 4022. Preferably, the system 4024 includes a calculation module 4024a configured to receive input regarding a desired depth plane or wavefront divergence and calculate appropriate light emitting regions to activate to form a parallax view with an appropriate amount of difference for the desired depth plane or wavefront divergence. Additionally, the calculation module 4024a may be configured to determine appropriate actuation of pixels of the spatial light modulator 4018 to form an image of the desired parallax view. The system 4024 may also include a synchronization module 4024b configured to synchronize activation of certain light-emitting regions of the light source 4026 with modulation of light by the spatial light modulator 4018 to form images to provide parallax views corresponding to those activated light-emitting regions. In addition, the system 4024 may include an eye tracking module 4024c that receives input from an eye tracking device 4022. For example, the eye tracking device 4022 may be a camera configured to image the eye 210. Based on the images captured by the eye tracking device 4022, the eye tracking module 4024c may be configured to determine the orientation of the pupil and extrapolate the line of sight of the eye 210. This information may be electronically communicated to the calculation module 4024a. The calculation module 4024a may be configured to select image content based on the line of sight or line of sight of the eye 210 (and preferably also based on the line of sight or line of sight of the viewer's other eye).

[0356] Since the light source 4026 may include an array of discrete light emitters, the size and shape of the light emitting region formed by the light emitters may be varied by activating selected ones of the light emitters as desired. For example, different emitting regions may be activated for different parallax views. In one example, elongated light emitting regions may be spaced horizontally, which may be desirable for horizontal parallax only driven accommodation. In another example, a circular light emitting region may have both horizontal and vertical displacement. In another example, the light emitting regions may have a luminance falloff. In another example, the light emitting regions may overlap. In another example, the light emitting regions may form an array. Thus, the light source 4026 (FIG. 25C) may include light emitters that are binary (simply turn on and off) and / or light emitters that incorporate grayscale (selectively emit light of variable intensity). In some implementations, the light source 4026 may include elements that switch at very high rates, including rates that exceed the parallax switching rate for the system 4001. For example, the light source 4026 may have a light output element that switches its light output on and off at a rate higher than the rate at which the parallax (intra-pupillary) images are switched in an implementation in which different intra-pupillary images are displayed at different times.

[0357] It should be understood that different amounts of wavefront divergence may be approximated by appropriate selection of physical distances separating the light emitters that are activated and form different intrapupillary images. The light emitters of the light sources 4026 may direct light from different angles through the projection optics to approximate different amounts of wavefront divergence and provide parallaxically dissimilar intrapupillary images. In some implementations, a relatively large distance between the individual light sources may provide a wavefront divergence that corresponds to a relatively near depth surface, while a relatively small distance between the individual light sources may provide a wavefront divergence that corresponds to a relatively far depth surface.

[0358] Referring again to FIG. 25C, in some implementations, the control system 4024 may include two parts: 1) light field generation; and 2) decomposed light field optimization. As discussed herein, to approximate the wavefront, an appropriate image is displayed on the spatial light modulator 4018 for each activated light emitting area of ​​the light source 4026. It should be understood that these images are created during the light field generation step, and the 3D scene is rendered from multiple slightly offset viewpoints that correspond to slight shifts in the activated light emitting areas. For example, to display a 5×5 light field, the 3D scene would be rendered 25 times from 25 different viewpoints arranged in a grid pattern. The locations of the viewpoints in the grid pattern correspond to the locations of the activated light source areas, and the rendered images would correspond to the images formed by the spatial light modulator.

[0359] It may be desirable to increase the brightness of an image formed by the spatial light modulator 4018. Advantageously, utilizing a light source 4026 comprising an array of light emitters allows for the formation of light-emitting regions having various shapes and sizes, which may be utilized to increase the brightness. In some implementations, the brightness may be increased by increasing the size of the activated light-emitting regions without significantly changing the image formed by the spatial light modulator 4018. The calculation module 4024a may be configured to determine the size and shape of the activated light-emitting regions using a split light field optimization. The module 4024a may be configured to utilize the input focal stack to create a series of patterns for display on the spatial light modulator 4018 and on the light source 4026, with the patterns configured to create a desired approximation to the focal stack in a least squares notion. The optimization utilizes the fact that small shifts in viewpoint do not significantly change the perceived image, and it is possible to generate a light-emitting region pattern that utilizes illumination from a larger area on the light source 4026 while displaying the same image on the spatial light modulator 4018.

[0360] The optimization problem can be formulated as a non-convex optimization problem, given below: [ka] In the expression, the projection operator [ka] performs a linear transformation (using a shift and add algorithm) from a 4D light field to a 3D focal stack. The problem is a non-negative matrix decomposition embedded in a deconvolution problem. An algorithm for solving the problem uses the Alternating Directional Multiplier Method (ADMM). Additional details regarding an exemplary method for solving the problem are discussed in Appendix I. It should be appreciated that module 4024a is configured to actively calculate, in real time, the appropriate size and shape of the luminous region based on the parallax view to be formed by the spatial light modulator 4018.

[0361] In some other implementations, the optimization problem may be formulated as a slightly different non-convex optimization problem as given below. [ka] where A and B represent the patterns displayed on a spatial light modulator (e.g., light source 4026 and spatial light modulator 4018 to form an image), y is the target 4D light field that is the desired output of the algorithm, and AB' is an operator that combines the spatial light modulator patterns to simulate the 4D light field emitted by a physical display when A and B are shown on the modulator. The problem is a non-negative matrix decomposition. The algorithm that solves the problem uses iterative optimization techniques to refine A and B from a random initial guess.

[0362] With continued reference to FIG. 25C, it should be appreciated that the flicker fusion threshold of the human visual system imposes a time constraint on the number of images that can be launched into the eye 210 while still being perceived as being launched simultaneously. For example, the processing bandwidth of the control system 4024 and the ability to switch between the light emitting areas of the light source 4026 and the light modulators of the spatial light modulator 4018 may limit the number of images that can be launched into the eye 210 within the duration allowed by the flicker fusion threshold. Given this finite number of images, the control system 4024 may be configured to make a selection regarding the images to be displayed. For example, within the flicker fusion threshold, the display system may be required to launch a set of parallax-dissimilar intrapupillary images into the eye, and each parallax view may in turn require images of different primary colors to form a full color image. In some implementations, the formation of a full color image using primary color images is diverged from the resolution of the desired accommodation response. For example, without being limited by theory, it may be possible to induce a desired accommodation response using a single color of light. In such cases, the parallaxically disparate intrapupillary images used to elicit an accommodation response would be only in a single color. As a result, it would not be necessary to form parallaxically disparate intrapupillary images using other colors of light, thereby freeing up time within the flicker fusion threshold for other types of images to be displayed. For example, a set of larger parallaxically disparate intrapupillary images may be generated to better approximate the wavefront.

[0363] In some other implementations, the control system 4024 may be configured to spend less time within the flicker fusion threshold to display images of colors of light to which the human visual system is less sensitive. For example, the human visual system is less sensitive to blue light than to green light. As a result, the display system may be configured to generate a greater number of images formed with green light than images formed with blue light.

[0364] Referring now to FIG. 25D, an example of a projection system 4003 is illustrated that includes an eye tracking system 4022 and a combiner eyepiece 1005 with a pupil expander 1035 configured to produce a non-infinity depth plane. In some implementations, the non-infinity depth plane may be at 3 meters, which results in a budgeted accommodation of about 2.5 meters to infinity. For example, given the tolerance of the human visual system for accommodation-vergence-divergence mismatch, virtual content at a distance of about 2.5 meters from the viewer to infinity may be placed on the 3 meter depth plane with little discomfort. In such a system, parallaxically dissimilar intrapupillary images may be used to drive accommodation for a range of narrower depth planes, potentially all closer to the viewer than a fixed "default" focal plane. In some implementations, the system may also incorporate an eye tracking system 4022 to determine the distance of the viewer's fixation, for example, based on the convergence and divergence angles of the viewer's eyes.

[0365] In some implementations, the light source 4026 may be replaced with a virtual light source formed on an image plane of an optical projection system. The optical projection system may include an actuator capable of scanning a beam of light across an area on the image plane corresponding to the virtual light source. To mimic the ability to activate discrete light-emitting areas of the light source 4026, the output of light by the projection system is synchronized with the movement of the actuator to output light to desired locations on the image plane at a particular time. Preferably, the rate at which the actuator is capable of scanning the beam of light across the image plane is high enough that all desired light output locations on the image plane can be accessed during the time frame during which any given intra-pupillary image is displayed. For example, during the amount of time during which a particular intra-pupillary image is displayed, the actuator is preferably capable of scanning the beam of light at least once, and preferably multiple times, across the area of ​​the image plane corresponding to the virtual 2D light source.

[0366] It should be understood that parallaxically dissimilar intra-pupillary images may be directed into a waveguide having multiple in-coupling regions with associated out-coupling regions as discussed herein. For each of these intra-pupillary images, image light may be routed to the desired in-coupling region by a variety of schemes, including a scanning fiber system as discussed with respect to FIG. 20, a moveable mirror system as discussed with respect to FIG. 21, and a system that forms images for the different in-coupling regions on different portions of a spatial light modulator as discussed with respect to FIG. 22.

[0367] Several wavefront approximation techniques are discussed in U.S. Patent Application Publication No. 2018 / 0113311, published April 26, 2018, and entitled “SYSTEM AND METHOD FOR PRESENTING IMAGE CONTENT ON MULIPLE DEPTH PLANES BY PROVIDING MULTIPLE INTRA-PUPIL PARALLAX VIEWS,” the entire disclosure of which is incorporated herein by reference. Other implementations

[0368] Various aspects, embodiments, implementations, or features of the described implementations can be used separately or in any combination. Various aspects of the described implementations can be implemented by software, hardware, or a combination of hardware and software. The described implementations can also be embodied as computer readable code on a computer readable medium for controlling a manufacturing operation or as computer readable code on a computer readable medium for controlling a manufacturing line. A computer readable medium is any data storage device that can store data that can then be read by a computer system. Examples of computer readable media include read-only memory, random acces...

Claims

1. A display system comprising: A light projection system; 1. A head-mountable display configured to project light into a user's eye and display virtual image content, the head-mountable display comprising at least one waveguide, the at least one waveguide comprising: a plurality of optical in-coupling regions configured to receive light from the optical projection system; a plurality of light out-coupling regions configured to output light to the eye of the user; a head mountable display comprising: processing electronics in communication with the head mountable display and the optical projection system; Equipped with The processing electronics includes one or more processors and one or more computer storage media that store instructions that, when executed by the one or more processors, cause the one or more processors to: determining a light outcoupling area associated with an eye posture of the eye; providing instructions for directing light from the optical projection system to an optical in-coupling region associated with the determined optical out-coupling region; A display system that performs an operation including:

2. The display system of claim 1, wherein determining the light external coupling area includes determining an intersection between the line of sight of the eye and one of the plurality of light external coupling areas.

3. A display system as described in claim 1, wherein the optical internal coupling regions are arranged in a row around at least one side of the plurality of external coupling regions.

4. The display system of claim 1, wherein the light projection system comprises at least one light source and at least one movable light emitter configured to output image light.

5. The display system of claim 4, wherein at least one of the movable light emitters comprises a scanning mirror.

6. The display system of claim 4, wherein at least one of the movable light launchers comprises a scanning fiber launcher.

7. The display system of claim 1, wherein the optical projection system comprises at least one light source and at least one spatial light modulator configured to modulate light from the light source.

8. The display system of claim 1, wherein the head-mountable display is configured to display virtual objects on multiple depth planes.

9. The display system of claim 8, wherein the operations include projecting a set of parallaxically disparate intrapupillary images of the virtual object into the eye and displaying the virtual object on one of the depth planes.

10. A display system as described in claim 9, wherein the operation includes bringing each of the set of parallaxly dissimilar intrapupillary images within a flicker fusion threshold.

11. The display system of claim 8, wherein the operation includes providing instructions for directing light to a plurality of internal coupling elements within an optical internal coupling region of the plurality of internal coupling regions associated with the determined optical external coupling region.

12. The display system of claim 8, further comprising at least one variable focus lens element on a user side of the at least one waveguide, the first variable focus lens element configured to modify the projected light and correct refractive error of the user's eye.

13. A display system as described in claim 12, wherein the operation further includes determining a fixation point of the eye and applying a correction corresponding to the fixation point.

14. The method of claim 13, further comprising: providing an inwardly facing imaging system configured to capture an image of one or more of the eyes of the user; and said operation further comprising: receiving an image of the user's eye captured by the inwardly facing imaging system; identifying the eye posture based on the received image; The display system of claim 1 further comprising:

15. The method of claim 15, wherein the at least one waveguide is one of a plurality of waveguides forming a waveguide stack, each of the waveguides comprising a plurality of the internal coupling regions and the external coupling regions; 10. The display system of claim 1, wherein the incoupling region of each of the waveguides is laterally displaced, as seen in a front plan view, when viewed from the direction of incident light incident on the incoupling region.

16. The outcoupling regions of the same waveguide are configured to output light with the same wavefront divergence; the outcoupling regions of the different waveguides are configured to output light with a different amount of wavefront divergence than the outcoupling regions of the at least one other waveguide; The display system of claim 15 , wherein the different amounts of wavefront divergence correspond to different depth planes.

17. The internal coupling region of each waveguide is configured to internally couple light in a range of wavelengths corresponding to a same primary color; 16. The display system of claim 15, wherein the incoupling regions of some waveguides are configured to incouple light in ranges of wavelengths corresponding to different primary colors than the incoupling regions of other waveguides.

18. The display system of claim 1, wherein the optical projection system comprises a plurality of projectors, each of the plurality of projectors being configured to provide image content for at most a subdivided portion of the field of view of the head-mountable display.

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