Holographic two-dimensional (2D) image projection for an augmented reality (AR) waveguide display

Abstract

Systems, methods, and / or apparatuses for a holographic projection module in a near-eye display device, which may display augmented reality / virtual reality (AR / VR) content to the user. In one aspect, a spatial light modulator (SLM) is illuminated by a planar wavefront, which the SLM modulates with a pattern and projects the patterned light through a projection lens to form a 2D hologram which is input to a waveguide display. Some examples may include a high-order filter to form an aperture in the Fourier domain controllable by the phase pattern displayed on the SLM; other examples may have no projection lenses, where the displayed SLM image corresponds to the user perceived Fourier domain image representation. Some examples may use two stacked SLMs, a complex wavefront modulation SLM, and / or a phase SLM with a mask (such as, e.g., a binary amplitude mask).

Description

HOLOGRAPHIC TWO-DIMENSIONAL (2D) IMAGE PROJECTION FOR AN AUGMENTED REALITY (AR) WAVEGUIDE DISPLAYCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This patent application claims benefit of and priority to U.S. provisional patent application Ser. No. 63 / 551 ,604 filed February 9, 2024.TECHNICAL FIELD

[0002] This patent application relates generally to augmented and / or virtual reality (AR / VR) near-eye display devices, and in particular, to a projection system for a waveguide display with a spatial light modulator (SLM) to be illuminated by a planar wavefront.BACKGROUND

[0003] With recent advances in technology, prevalence and proliferation of content creation and delivery has increased greatly in recent years. In particular, interactive content such as virtual reality (VR) content, augmented reality (AR) content, mixed reality (MR) content, and content within and associated with a real and / or virtual environment (e.g., a “metaverse”) has become appealing to consumers.

[0004] To facilitate delivery of this and other related content, service providers have endeavored to provide various forms of wearable display systems. One such example may be a head-mounted display (HMD) device, such as a wearable eyewear, a wearable headset, or eyeglasses. In some examples, the HMD device may project or direct light to display virtual objects or combine images of real objects with virtual objects, as in virtual reality (VR), augmented reality (AR), or mixed reality (MR) applications. For example, in an AR system, a user may view both images of virtual objects (e.g., computer-generated images (CGIs)) and the surrounding environment. (HMD devices may also present interactive content, where a user’s (wearer’s) gaze may be used as input for the interactive content.

[0005] Virtual reality (VR), augmented reality (AR), and / or mixed reality (MR) applications may employ holography, such as is described in U.S. Pat. No. 9,964,925 to Lee et al. (entitled “HOLOGRAPHIC DISPLAY ARCHITECTURE”), assigned to the same assignee as the instant application, which is hereby incorporated by reference for all purposes (hereinafter, “the ‘925 patent”). In the ‘925 patent, an HMD has a holographic display including a partially coherent light source and a beam conditioner that conditions the light into one or more beams of light. The holographic display also includes one or more spatial light modulators (SLMs) configured to encode the one ormore beams of light using a hologram of a virtual reality image, as well as an objective lens and a conversion lens. The objective lens is positioned to create an intermediate image at a Fourier plane, where the intermediate image is a Fourier transform of the hologram. The conversion lens performs a Fourier transform of the intermediate image to generate an output hologram. The conversion lens also magnifies a portion of the output hologram and directs the magnified portion of the output hologram to an exit pupil of the HMD.SUMMARY

[0006] In accordance with a first aspect of the present disclosure, there is provided an augmented reality / virtual reality (AR / VR) near-eye display device, comprising: a display system to render AR / VR content comprising: a waveguide display; and a holographic two-dimensional (2D) projection module employing at least one spatial light modulator (SLM), wherein the at least one SLM is illuminated by a planar wavefront; an eye tracking system; and a controller to manage the display system and the eye tracking system.

[0007] In some embodiments, the holographic 2D projection module further comprises: a projection lens.

[0008] In some embodiments, the holographic 2D projection module further comprises: a high-order filter.

[0009] In some embodiments, the holographic 2D projection module further comprises: a half-band filter.

[0010] In some embodiments, the at least one SLM comprises a first SLM and a second SLM, wherein the first SLM and the second SLM are stacked.

[0011] In some embodiments, the first SLM and the second SLM are tiltable to provide angular filtering.

[0012] In some embodiments, the at least one SLM is a complex wavefront modulation SLM.

[0013] In accordance with a second aspect of the present disclosure, there is provided a near-eye display device, comprising: a waveguide display to display augmented reality I virtual reality (AR / VR) content to a user; and a holographic projection module to generate and project a two-dimensional (2D) image into the waveguide display for the waveguide display to form three-dimensional (3D) content for the user, wherein the holographic projection module comprises: a spatial light modulator (SLM) to be illuminated by a planar wavefront and then to modulate andto project the modulated light with an on / off pattern such that multiple eyeboxes of varying densities are formed.

[0014] In some embodiments, the SLM is a complex wavefront modulation SLM.

[0015] In some embodiments, the SLM is a phase SLM with a binary amplitude mask.

[0016] In some embodiments, the holographic 2D projection module further comprises: a controller to control the SLM to modulate and project on / off patterned light.

[0017] In some embodiments, the waveguide display comprises: an incoupling grating to receive the modulated light from the SLM; and an out-coupling grating to project the modulated light out of the waveguide display to an eye of the user.

[0018] In accordance with a third aspect of the present disclosure, there is provided a near-eye display device, comprising: a waveguide display to display augmented reality I virtual reality (AR / VR) content to a user; and a holographic projection module to generate and project a two-dimensional (2D) image into the waveguide display for the waveguide display to form three-dimensional (3D) content for the user, wherein the holographic projection module comprises: a spatial light modulator (SLM) to be illuminated by a planar wavefront and then to modulate and to project the patterned light planar wavefront; a holographic optical element (HOE) to receive and project the patterned light planar wavefront; and a switchable lens to receive the patterned light planar wavefront from the HOE and project the 2D image into the waveguide display.

[0019] In some embodiments, the switchable lens is a Pancharatnam Berry Phase (PBP) lens.

[0020] In some embodiments, the switchable lens is at least one of a liquid lens or a focus tunable liquid crystal (LC) lens.

[0021] In some embodiments, the HOE is a film stack angular filter.

[0022] In some embodiments, the holographic projection module further comprises: a liquid crystal (LC) steering lens.

[0023] In some embodiments, the waveguide display comprises: a right- handed waveguide.

[0024] In some embodiments, the holographic projection module furthercomprises: a laser source to provide the planar wavefront to illuminate the SLM.

[0025] In some embodiments, the near-eye display device further comprising: a controller to control the SLM, the HOE, and the switchable lens.BRIEF DESCRIPTION OF DRAWINGS

[0026] Features of the present disclosure are illustrated by way of example and not limited in the following figures, in which like numerals indicate like elements. One skilled in the art will readily recognize from the following that alternative examples of the structures and methods illustrated in the figures can be employed without departing from the principles described herein.

[0027] FIG. 1 illustrates a block diagram of an artificial reality system environment including a near-eye display, according to an example.

[0028] FIGS. 2A-2C illustrate various views of a near-eye display device in the form of a head-mounted display (HMD) device, according to examples.

[0029] FIG. 3 illustrates a perspective view of a near-eye display in the form of a pair of glasses, according to an example.

[0030] FIG. 4A is a block diagram of a waveguide holography system illustrating a fundamental restraint on waveguide holography of different pupil replication densities at different fields of view (FoVs), while FIGS. 4B-4C illustrate possible waveguide holography system configurations which may be employed in FIG. 4A.

[0031] FIGS. 5A and 5B illustrate configurations of waveguide holography display systems which mitigate different pupil replication densities at different fields of view (FoVs), according to various examples.

[0032] FIGS. 6A through 6E are block diagrams of waveguide holography systems illustrating various configurations of holographic projection modules where a two-dimensional (2D) hologram is projected substantially directly into a waveguide display, according to various examples.

[0033] FIGS. 7 and 8 illustrate different configurations of a compact foveated 2D projection module for a waveguide display, according to some examples.DETAILED DESCRIPTION

[0034] For simplicity and illustrative purposes, the present application is described by referring mainly to examples thereof. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. It will be readily apparent, however, that the present application may be practiced without limitation to these specific details. In otherinstances, some methods and structures readily understood by one of ordinary skill in the art have not been described in detail so as not to unnecessarily obscure the present application. As used herein, the terms “a” and “an” are intended to denote at least one of a particular element, the term “includes” means includes but not limited to, the term “including” means including but not limited to, and the term “based on” means based at least in part on.

[0035] Near-eye display technology is evolving rapidly. Especially for augmented reality (AR), various see-through near-eye display architectures have been developed recently. Among the architectures, pupil-replicating waveguide image combiner is a strong candidate for AR wearable display devices because of its compact form factor. Despite the unique advantages of waveguide image combiners, there are some limitations. For example, achieving sufficient brightness using conventional light sources such as micro light-emitting diodes is challenging. Laser light sources may be much more power efficient than micro LEDs, however, the coherent light interaction causes several artifacts and degrades the image quality. Further challenges with waveguides due to their projection modules having limited degree of freedom include uniformity, resolution, dynamic range, and efficiency.

[0036] In some examples of the present disclosure, holographic two- dimensional (2D) image projection may be provided for waveguide displays. A projection module for a waveguide display may include a spatial light modulator (SLM) to be illuminated by a planar wavefront. The projection module may also include a projection lens to project a 2D hologram into the waveguide and a high-order filter to form an aperture in the Fourier domain controllable by the phase pattern displayed on the SLM. The projection module may further utilize lens-less projection and a direct- view SLM. The displayed SLM image corresponds to the user perceived Fourier domain image representation. The projection module may also include a second SLM or a complex wavefront modulation SLM utilizing the tilted SLM to modify the user perceived image, in some examples. As a light source, the system may utilize a single mode laser, a multi-mode laser, a laser diode, a super luminance LED (SLED), or an LED with chromatic filter.

[0037] While some advantages and benefits of the present disclosure are apparent, other advantages and benefits may include improvements in waveguide display uniformity, resolution, higher dynamic range, and enhanced efficiency.

[0038] FIG. 1 illustrates a block diagram of an artificial reality systemenvironment 100 including a near-eye display, according to an example. As used herein, a “near-eye display” may refer to a device (e.g., an optical device) that may be in close proximity to a user’s eye. As used herein, “artificial reality” may refer to aspects of, among other things, a “metaverse” or an environment of real and virtual elements and may include use of technologies associated with virtual reality (\ / R), augmented reality (AR), and / or mixed reality (MR). As used herein, “augmented reality (AR) I virtual reality (VR),” “AR / VR,” and similar terms may refer to any of these technologies (e.g., including mixed reality (MR) even though not directly identified). As used herein a “user” may refer to a user or wearer of a “near-eye display.”

[0039] As shown in FIG. 1 , the artificial reality system environment 100 may include a near-eye display 120, an optional external imaging device 150, and an optional input / output interface 140, each of which may be coupled to a console 110. The console 110 may be optional in some instances as the functions of the console 110 may be integrated into the near-eye display 120. In some examples, the near- eye display 120 may be a head-mounted display (HMD) that presents content to a user.

[0040] In some instances, for a near-eye display system, it may generally be desirable to expand an eye box, reduce display haze, improve image quality (e.g., resolution and contrast), reduce physical size, increase power efficiency, and increase or expand field of view (FoV). As used herein, “field of view” (FoV) may refer to an angular range of an image as seen by a user, which is typically measured in degrees as observed by one eye (for a monocular HMD or both eyes (for binocular HMDs).

[0041] In some examples, in a near-eye display system, light from the surrounding environment may traverse a “see-through” region of a waveguide display (e.g., a transparent substrate) to reach a user’s eyes. For example, in a near-eye display system, light of projected images may be coupled into a transparent substrate of a waveguide, propagate within the waveguide, and be coupled or directed out of the waveguide at one or more locations to replicate exit pupils and expand the eyebox. As used herein, an “eyebox” may, depending on context refer to the 3D volume and / or 2D region within which a user’s eye may be located relative to the near-eye device and from which a displayed image may be viewed. In some circumstances , the “eyebox” may have a more concise or specialized meaning, such as in the descriptions of FIGS. 4A, 4B, 5A, and 5B below.

[0042] In some examples, the near-eye display 120 may include one or morerigid bodies, which may be rigidly or non-rigidly coupled to each other. In some examples, a rigid coupling between rigid bodies may cause the coupled rigid bodies to act as a single rigid entity, while in other examples, a non-rigid coupling between rigid bodies may allow the rigid bodies to move relative to each other.

[0043] In some examples, the near-eye display 120 may be implemented in any suitable form-factor, including an HMD, a pair of glasses, or other similar wearable eyewear or device. Examples of the near-eye display 120 are further described below with respect to FIGS. 2A-2C and 3. Additionally, in some examples, the functionality described herein may be used in an HMD or headset that may combine images of an environment external to the near-eye display 120 and artificial reality content (e.g., computer-generated images). Therefore, in some examples, the near-eye display 120 may augment images of a physical, real-world environment external to the near-eye display 120 with generated and / or overlaid digital content (e.g., images, video, sound, etc.) to present an augmented reality to a user (e.g., virtual reality (VR), augmented reality (AR), and / or mixed reality (MR)).

[0044] In some examples, the near-eye display 120 may include any number of display electronics 122, display optics 124, and an eye tracking unit 130. In some examples, the near-eye display 120 may also include one or more locators 126, one or more position sensors 128, and an inertial measurement unit (IMU) 132. In some examples, the near-eye display 120 may omit any of the eye tracking unit 130, the one or more locators 126, the one or more position sensors 128, and the IMU 132, or may include additional elements.

[0045] In some examples, the display electronics 122 may display or facilitate the display of images to the user according to data received from, for example, the optional console 110. In some examples, the display electronics 122 may include one or more display panels. In some examples, the display electronics 122 may include any number of pixels to emit light of a predominant color such as red, green, blue, white, or yellow. In some examples, the display electronics 122 may display a three- dimensional (3D) image by, e.g., using stereoscopic effects produced by two- dimensional (2D) panels to create a subjective perception of image depth.

[0046] In some examples, the near-eye display 120 may include a projector (not shown), which may form an image in angular domain for direct observation by a viewer’s eye through a pupil. The projector may employ a controllable light source (e.g., a laser source) and a micro-electromechanical system (MEMS) beam scannerto create a light field from, for example, a collimated light beam. In some examples, the same projector or a different projector may be used to project a fringe pattern on the eye, which may be captured by a camera and analyzed (e.g., by the eye tracking unit 130) to determine a position of the eye (the pupil), a gaze, etc.

[0047] In some examples, the display optics 124 may display image content optically (e.g., using optical waveguides and / or couplers) or magnify image light received from the display electronics 122, correct optical errors associated with the image light, and / or present the corrected image light to a user of the near-eye display 120. In some examples, the display optics 124 may include a single optical element or any number of combinations of various optical elements as well as mechanical couplings to maintain relative spacing and orientation of the optical elements in the combination. In some examples, one or more optical elements in the display optics 124 may have an optical coating, such as an anti-reflective coating, a reflective coating, a filtering coating, and / or a combination of different optical coatings.

[0048] In some examples, the display optics 124 may also be designed to correct one or more types of optical errors, such as 2D optical errors, 3D optical errors, or any combination thereof. Examples of 2D errors may include barrel distortion, pincushion distortion, longitudinal chromatic aberration, and / or transverse chromatic aberration. Examples of 3D errors may include spherical aberration, chromatic aberration field curvature, and astigmatism.

[0049] In some examples, the one or more locators 126 may be objects located in specific positions relative to one another and relative to a reference point on the near-eye display 120. In some examples, the optional console 110 may identify the one or more locators 126 in images captured by the optional external imaging device 150 to determine the artificial reality headset’s position, orientation, or both. The one or more locators 126 may each be a light-emitting diode (LED), a corner cube deflector, a reflective marker, a type of light source that contrasts with an environment in which the near-eye display 120 operates, or any combination thereof.

[0050] In some examples, the external imaging device 150 may include one or more cameras, one or more video cameras, any other device capable of capturing images including the one or more locators 126, or any combination thereof. The optional external imaging device 150 may be configured to detect light emitted or reflected from the one or more locators 126 in a field of view of the optional external imaging device 150.

[0051] In some examples, the one or more position sensors 128 may generate one or more measurement signals in response to motion of the near-eye display 120. Examples of the one or more position sensors 128 may include any number of accelerometers, gyroscopes, magnetometers, and / or other motion-detecting or errorcorrecting sensors, or any combination thereof.

[0052] In some examples, the IMU 132 may be an electronic device that generates fast calibration data based on measurement signals received from the one or more position sensors 128. The one or more position sensors 128 may be located external to the IMU 132, internal to the IMU 132, or any combination thereof. Based on the one or more measurement signals from the one or more position sensors 128, the IMU 132 may generate fast calibration data indicating an estimated position of the near-eye display 120 that may be relative to an initial position of the near-eye display 120. For example, the IMU 132 may integrate measurement signals received from accelerometers overtime to estimate a velocity vector and integrate the velocity vector over time to determine an estimated position of a reference point on the near-eye display 120. Alternatively, the IMU 132 may provide the sampled measurement signals to the optional console 110, which may determine the fast calibration data.

[0053] The eye tracking unit 130 may include one or more eye tracking systems. As used herein, “eye tracking” may refer to determining an eye’s position or relative position, including orientation, location, and / or gaze of a user’s eye. In some examples, an eye tracking system may include an imaging system that captures one or more images of an eye and may optionally include a light emitter, which may generate light (e.g., a fringe pattern) that is directed to an eye such that light reflected by the eye may be captured by the imaging system (e.g., a camera).

[0054] In some examples, the near-eye display 120 may use the orientation of the eye to introduce depth cues (e.g., blur image outside of the user’s main line of sight), collect heuristics on the user interaction in the virtual reality (VR) media (e.g., time spent on any particular subject, object, or frame as a function of exposed stimuli), some other functions that are based in part on the orientation of at least one of the user’s eyes, or any combination thereof. In some examples, because the orientation may be determined for both eyes of the user, the eye tracking unit 130 may be able to determine where the user is looking or predict any user patterns, etc.

[0055] In some examples, the input / output interface 140 may be a device that allows a user to send action requests to the optional console 110. As used herein, an“action request” may be a request to perform a particular action. For example, an action request may be to start or to end an application or to perform a particular action within the application. The input / output interface 140 may include one or more input devices. Example input devices may include a keyboard, a mouse, a game controller, a glove, a button, a touch screen, or any other suitable device for receiving action requests and communicating the received action requests to the optional console 110. In some examples, an action request received by the input / output interface 140 may be communicated to the optional console 110, which may perform an action corresponding to the requested action.

[0056] In some examples, the optional console 110 may provide content to the near-eye display 120 for presentation to the user in accordance with information received from one or more of external imaging device 150, the near-eye display 120, and the input / output interface 140. For example, in the example shown in FIG. 1 , the optional console 110 may include an application store 112, a headset tracking module 114, a virtual reality engine 116, and an eye tracking module 118. Some examples of the optional console 110 may include different or additional modules than those described in conjunction with FIG. 1. Functions further described below may be distributed among components of the optional console 110 in a different manner than is described here.

[0057] In some examples, the optional console 110 may include a processor and a non-transitory computer-readable storage medium storing instructions executable by the processor. The processor may include multiple processing units executing instructions in parallel. The non-transitory computer-readable storage medium may be any memory, such as a hard disk drive, a removable memory, or a solid-state drive (e.g., flash memory or dynamic random access memory (DRAM)). In some examples, the modules of the optional console 110 described in conjunction with FIG. 1 may be encoded as instructions in the non-transitory computer-readable storage medium that, when executed by the processor, cause the processor to perform the functions further described below. It should be appreciated that the optional console 110 may or may not be needed or the optional console 110 may be integrated with or separate from the near-eye display 120.

[0058] In some examples, the application store 112 may store one or more applications for execution by the optional console 110. An application may include a group of instructions that, when executed by a processor, generates content forpresentation to the user. Examples of the applications may include gaming applications, conferencing applications, video playback application, or other suitable applications.

[0059] In some examples, the headset tracking module 1 14 may track movements of the near-eye display 120 using slow calibration information from the external imaging device 150. For example, the headset tracking module 114 may determine positions of a reference point of the near-eye display 120 using observed locators from the slow calibration information and a model of the near-eye display 120. Additionally, in some examples, the headset tracking module 114 may use portions of the fast calibration information, the slow calibration information, or any combination thereof, to predict a future location of the near-eye display 120. In some examples, the headset tracking module 1 14 may provide the estimated or predicted future position of the near-eye display 120 to the virtual reality engine 116.

[0060] In some examples, the virtual reality engine 116 may execute applications within the artificial reality system environment 100 and receive position information of the near-eye display 120, acceleration information of the near-eye display 120, velocity information of the near-eye display 120, predicted future positions of the near-eye display 120, or any combination thereof from the headset tracking module 114. In some examples, the virtual reality engine 116 may also receive estimated eye position and orientation information from the eye tracking module 118. Based on the received information, the virtual reality engine 1 16 may determine content to provide to the near-eye display 120 for presentation to the user.

[0061] In some examples, a location of a projector of a display system may be adjusted to enable any number of design modifications. For example, in some instances, a projector may be located in front of a viewer’s eye (i.e., “front-mounted” placement). In a front-mounted placement, in some examples, a projector of a display system may be located away from a user’s eyes (i.e., “world-side”). In some examples, an HMD device may utilize a front-mounted placement to propagate light towards a user’s eye(s) to project an image.

[0062] As mentioned herein, a holographic 2D image projection module for a waveguide display may include a spatial light modulator (SLM) to be illuminated by a planar wavefront. The projection module may also include a projection lens to project a 2D hologram into the waveguide and a high-order filter to form an aperture in the Fourier domain controllable by the phase pattern displayed on the SLM.

[0063] FIGS. 2A-2C illustrate various views of a near-eye display device in the form of a head-mounted display (HMD) device 200, according to examples. In some examples, the HMD device 200 may be a part of a virtual reality (VR) system, an augmented reality (AR) system, a mixed reality (MR) system, another system that uses displays or wearables, or any combination thereof. As shown in front perspective view 200A of FIG. 2A, the HMD device 200 may include a body 220 and a head strap 230. The front perspective view 200A of the HMD device 200 further shows a bottom side 223, a front side 225, and a right side 229 of the body 220. In some examples, the head strap 230 may have an adjustable or extendible length. In particular, in some examples, there may be a sufficient space between the body 220 and the head strap 230 of the HMD device 200 for allowing a user to mount the HMD device 200 onto the user’s head. For example, the length of the head strap 230 may be adjustable to accommodate a range of user head sizes. In some examples, the HMD device 200 may include additional, fewer, and / or different components such as a display 210 to present a user / wearer AR / VR content and a camera to capture images or videos of the user’s / wearer’s environment.

[0064] As shown in the bottom perspective views 200B and 200C of FIGS. 2B and 2C, respectively (which each also show the left side 227 of the HMD 200), the display 210 may include two separate displays (one for each eye). In some examples, the display 210 may include one or more display assemblies and present, to a user (wearer), media or other digital content including virtual and / or augmented views of a physical, real-world environment with computer-generated elements. Examples of the media or digital content presented by the HMD device 200 may include images (e.g., 2D or 3D images), videos (e.g., 2D or 3D videos), audio, or any combination thereof. In some examples, the user may interact with the presented images or videos through eye tracking sensors enclosed in the body 220 of the HMD device 200. The eye tracking sensors may also be used to adjust and improve quality of the presented content.

[0065] In some examples, the HMD device 200 may include various sensors (not shown), such as depth sensors, motion sensors, position sensors, and / or eye tracking sensors. Some of these sensors may use any number of structured or unstructured light patterns for sensing purposes. In some examples, the HMD device 200 may include an input / output interface for communicating with a console communicatively coupled to the HMD device 200 through wired or wireless means. Insome examples, the HMD device 200 may include a virtual reality engine (not shown) that may execute applications within the HMD device 200 and receive depth information, position information, acceleration information, velocity information, predicted future positions, or any combination thereof of the HMD device 200 from the various sensors.

[0066] In some examples, the information received by the virtual reality engine may be used for producing a signal (e.g., display instructions) to the display 210. In some examples, the HMD device 200 may include locators (not shown), which may be located in fixed positions on the body 220 of the HMD device 200 relative to one another and relative to a reference point. Each of the locators may emit light that is detectable by an external imaging device. This may be useful for the purposes of head tracking or other movement / orientation. It should be appreciated that other elements or components may also be used in addition or in lieu of such locators.

[0067] It should be appreciated that in some examples, a projector mounted in a display system may be placed near and / or closer to a user’s eye (i.e. , “eye-side”). In some examples, and as discussed herein, a projector for a display system shaped like eyeglasses may be mounted or positioned in a temple arm (i.e., a top far corner of a lens side) of the eyeglasses. It should be appreciated that, in some instances, utilizing a back-mounted projector placement may help to reduce size or bulkiness of any required housing required for a display system, which may also result in a significant improvement in user experience for a user.

[0068] In some examples, a holographic 2D image projection module for a waveguide display may include an SLM to be illuminated by a planar wavefront. The projection module may also include a projection lens to project a 2D hologram into the waveguide and a high-orderfilter to form an aperture in the Fourier domain controllable by the phase pattern displayed on the SLM. The projection module may further utilize lens-less projection and a direct-view SLM. The projection module may also include a second SLM or a complex wavefront modulation SLM utilizing the tilted SLM to modify the user perceived image, in some examples.

[0069] FIG. 3 is a perspective view of a near-eye display 300 in the form of a pair of glasses (or other similar eyewear), according to an example. In some examples, the near-eye display 300 may be a specific example of near-eye display 120 of FIG. 1 and may be configured to operate as a virtual reality (VR) display, an augmented reality (AR) display, and / or a mixed reality (MR) display.

[0070] In some examples, the near-eye display 300 may include a frame 305 and a display 310. In some examples, the display 310 may be configured to present media or other content to a user. In some examples, the display 310 may include display electronics and / or display optics, similar to components described with respect to FIGS. 1 and 2A-2C. For example, as described above with respect to the near-eye display 120 of FIG. 1 , the display 310 may include a liquid crystal display (LCD) display panel, a light-emitting diode (LED) display panel, or an optical display panel (e.g., a waveguide display assembly). In some examples, the display 310 may also include any number of optical components, such as waveguides, gratings, lenses, mirrors, etc. In other examples, the display 310 may include a projector, or in place of the display 310 the near-eye display 300 may include a projector.

[0071] In some examples, the near-eye display 300 may further include various sensors on orwithin a frame 305. In some examples, the various sensors may include any number of depth sensors, motion sensors, position sensors, inertial sensors, and / or ambient light sensors, as shown. In some examples, the various sensors may include any number of image sensors configured to generate image data representing different fields of views in one or more different directions. In some examples, the various sensors may be used as input devices to control or influence the displayed content of the near-eye display, and / or to provide an interactive virtual reality (VR), augmented reality (AR), and / or mixed reality (MR) experience to a user of the near- eye display 300. In some examples, the various sensors may also be used for stereoscopic imaging or other similar applications.

[0072] Holographic displays may be considered to have a tradeoff between the FoV and the size of the viewing eyebox, i.e., the area in which the eye must be located to see the image. Together, these two quantities describe the etendue of the display, a quantity which measures the product of the area and solid angle of emitted light from a surface in an optical system. In conventional, non-holographic displays, obtaining large etendue is generally not a challenge and can be provided, for example, by a display panel backlight that has large area and range of emission angles. However, in a holographic display the etendue is determined by the number of degrees of freedom (i.e. pixels) on the spatial light modulator (SLM).

[0073] In an article written by, inter alia, a named inventor hereof, entitled Waveguide Holography: Towards True 3D Holographic Glasses (arXiv:2221 ,02784v1 , published 04 November 2022; which is incorporated by reference for all purposes andhereinafter referred to as “Waveguide Holography’'), a display architecture employing the advantages of both waveguide displays and holographic displays is discussed.

[0074] In near-eye display applications, the waveguide image combiner or waveguide display may be a thin, transparent slab that guides the light as a total internal reflection (TIR) mode and replicates the exit pupils to be delivered to the user’s eye. These waveguides can be designed using different types of light coupling elements. Geometric waveguides use partially reflective surfaces inside the slab to re-direct and extract the light from the waveguide. Diffractive waveguides may utilize surface relief gratings, volume Bragg gratings, polarization gratings, and meta surface or geometric phase elements as in / out-couplers. TIR propagation allows the optical path to be secured in the waveguide without being obstructed, while no bulky projector or imaging optics are needed to be placed in front of user’s eye. The image projector of a waveguide display is typically located at the temple side with an infinity corrected lens, providing high resolution images. One advantage of a waveguide is its etendue expansion capability by pupil replications. This provides a sufficient eyebox with a fairly large field of view while many other architectures suffer from their trade-off relation imposed by limited etendue. Such advantages make waveguide displays a leading technology of AR displays.

[0075] Despite the advantages of waveguide displays, there are some limitations to be addressed. First, waveguides can only convey a fixed depth, typically as infinity conjugate images. If finite-conjugate images are projected into the waveguide, the pupil replication process produces copies of different optical paths and aberrations that create severe ghost noise, which is often called focus spread effect. Generating natural focus cues and addressing the vergence-accommodation conflict are among the challenging goals of AR in the pursuit of realistic and comfortable visual experiences. Dual or multi-imaging plane waveguide architectures have been studied, but inherently lead to a bulkier form factor and diminished performance, along with added hardware restrictions. Additionally, achieving sufficient brightness with conventional light sources, such as micro LEDs, is challenging due to the low efficiency of waveguide image combiners. Although laser light sources may greatly reduce the loss from coupling efficiency, their use with waveguides may be restricted because coherent light interaction during TIR propagation leads to artifacts and significant image quality degradation.

[0076] On the other hand, holographic display technology, where a wavefrontof light is modulated using SLMs, is believed to be an advantageous 3D display approach. It may also offer unique benefits such as aberration-free, high-resolution images, per-pixel depth control, ocular parallax depth cues, vision correction functionality, as well as a large color gamut. Moreover, progress has been made in the field of computer-generated hologram (CGH) rendering. Several conventional issues with holographic displays, including speckle, image quality, and heavy computational load, have been shown to be resolved with the help of enhanced CGH rendering models and the increased computing power of recent graphics processing units (GPUs). However, designing a compact architecture for near-eye holographic displays remains an unsolved problem due to limited etendue. Retinal projection type designs have been explored with a holographic projector at the temple side that projects the hologram via oblique free-space projection to the eyepiece combiner. However, such configurations have limited space and angular bandwidth to transmit enough etendue from the temple side to the eyepiece even with mechanical pupil steering, making the ergonomic glasses form factor an even more ambitious goal.

[0077] In Waveguide Holography, the system consists of a collimated laser light source, a spatial light modulator (SLM), an exit-pupil expanding (EPE) waveguide with surface relief gratings, and linear polarizers laminated on the SLM and out-coupler of the waveguide. One major difference from conventional waveguide displays is that the hologram projection module replaces the image projector. The SLM is placed without any projection lens, eliminating the need of physical propagation distance, as well as achieving a light-weight design. The input light is modulated by the SLM and coupled by the in-coupler grating into the waveguide. The light propagates in total internal reflection mode and is diffracted by an exit-pupil expanding (EPE) grating and out- coupler grating that may be designed as leaky gratings. This pupil-replication process generates manifold shifted copies of the wavefront having different optical paths inside the waveguide, that interfere with each other so that the phase and intensity of the final output wavefront is inextricably scrambled.

[0078] FIG. 4A is a planar view 400A of a block diagram of a waveguide holography system which illustrates a fundamental restraint on waveguide holography: the different pupil replication densities at different fields of view (FoVs). FIGS, 4B and 4C, which are based on Figure 1a of Waveguide Holography, are a perspective cut- through view 400B illustrating a portion of a possible configuration of the system in FIG. 4A and a planar view 400C of a block diagram of possible hologram projectionmodule which may be employed, respectively. In each of FIGS. 4A-4C and the following drawings, an SLM is shown projecting light into a waveguide; however, as would be known by one of ordinary skill in the art, a light source (not shown in FIGS. 4A-4C, 5A-5B, and / or 6A-6E) may illuminate the SLM with a planar wavefront, which the SLM modulates and projects. For example, FIG. 4C shows light from an external light source (not shown) which illuminates the SLM by reflecting off a beamsplitter, and the SLM modulates that light and projects the modulated light towards the waveguide back through the beamsplitter. As other examples, FIGS. 7 and 8 show the light source (i.e., laser sources 705 & 805) which illuminates the SLM (i.e. , SLMs 710 & 810), which then modulate the light and project the modulated light towards the waveguide. Accordingly, although the SLM may be described herein as “projecting” light towards the waveguide, it is understood that the SLM may be illuminated by an input wavefront, which may be planar, from a light source which may not necessarily be shown.

[0079] In FIG. 4A, a spatial light modulator (SLM) 410A projects modulated light 415A into a waveguide 420A which has an in-coupling grating 421 A which sends the input light through the interior of the waveguide 420A, where an out-coupling grating 423A projects the light towards a user’s eye 450A. In some examples, the in-coupling grating 421 A may be disposed on the other side of the waveguide 420A or integrated inside the waveguide 420A, and / or may be functionally distributed among a number of gratings, and may include diffractive, reflective, geometric, etc., gratings. Similarly, the out-coupling grating 423A may be disposed in any suitable location, and / or may be functionally distributed among a number of gratings, and may include diffractive, reflective, geometric, etc., gratings. Similarly, the SLM 410A may be disposed in other locations relative to the waveguide 420A, and / or functionally integrated into another component, and / or functionally distributed among multiple components, as would be understood by one of ordinary skill in the art. The SLM 410A may be communicatively connected to, and / or under the control of, a controller 480A, and the controller 480A may be communicatively connected to, and / or controlling, other components in the near-eye display system (e.g., one or more light sources, projectors, active polarizers, filters, etc.). The controller 480A may include a processor 483A and a memory 485A which may store instructions executable by the processor 483A to perform any of the methods described herein.

[0080] In FIG. 4A (and similarly in some of the following figures), one or moreeyeboxes 440A may be conceptual representations of different possible apertures which may be formed, and which the user’s eye 450A may see, in the various arbitrary locations relative to the waveguide 420A where the user’s eye 450A may be disposed. Specifically in FIG. 4A, the eyeboxes 440A which may be projected from the waveguide 420A may include multiple diagonal columns where how dark the boxes are indicates the relative densities, viz., a first diagonal column of eyeboxes (the darkest) has the greatest density, a second diagonal column of eyeboxes has somewhat less density (in mid-gray), a third diagonal column of eyeboxes has even less density (the lightest), and so on.

[0081] This difference in pupil replication densities at different fields of view (FoVs), as shown by the example in FIG. 4A, is a fundamental restraint on waveguide holography. As shown by a pupil replication density arrow 460A in FIG. 4A, the pupil replication densities of some eyeboxes may be too dense (redundancy), while the pupil replication densities of other eyeboxes may be too sparse (vignetting).

[0082] In FIG. 4B, a perspective view 400B shows a portion of a configuration similar to that employed in FIG, 4A, although in FIG. 4B, an SLM 41 OB is on the other side of a pupil replicating waveguide 420B from the user’s eye 450B. More specifically, FIG. 4B shows the SLM 41 OB projecting a light wavefront into the pupil replicating waveguide 420B which has an in-coupling grating 421 B which sends the input light through the interior of the waveguide 420B, where an out-coupling grating 423B projects the light towards a user’s eye 450B. Similarly to FIG. 4A, one or more eyeboxes 440B in FIG. 4B may be conceptual representations of different possible apertures which may be formed, and which the user’s eye 450A may see, in the various locations relative to the waveguide 420A as projected by the out-coupling gratings 423B.

[0083] In FIG. 4C, a magnified planar view 400C shows a possible construction for the SLM 410B (or 410A) in a hologram projection module. In the hologram projection module of FIG. 4C, a laser light source (not shown in FIG. 4C) provides light to the SLM 410C by reflecting it off of a beamsplitter (BS) 416C; the SLM 410C receives that light, modulates it, and projects a light wavefront into a linear polarizer (LP) 412C and a half wave plate (HWP) 414C, through the BS 416C, towards an incoupling grating on a waveguide (WG) 420C, in which the input light propagates through the interior of the WG 420C. In both FIGS. 4B and 4G, a controller (not shown) may be communicatively connected to, and / or controlling, any of the components inthe near-eye display system whether shown or not shown herein (such as, e.g., the SLM 410B / C, the LP 412C, the gratings 421 B and / or 423B — if active, any one or more laser sources, filters, etc.).

[0084] As is known to one of ordinary skill in the art, waveguide displays have challenges such as achieving sufficient brightness with conventional light sources, uniformity, resolution, dynamic range, and / or efficiency. One of the main constraints of waveguide display technology is the different pupil replication density at different FoVs illustrated in FIG. 4A. As shown by the example of FIG. 4A, the pupil replications may range from the too dense (where there may be redundancy) to the too sparse (vignetting), as indicated by the two-headed pupil replication density arrow 460A.

[0085] Thus, systems such as shown in FIGS. 4A, 4B, and / or 4C may not have sufficient etendue (e.g., for FoV of about 10 degrees). By contrast, various examples according to the present disclosure may, inter alia, provide sufficient etendue. Some examples discussed herein may provide optimization including a better etendue.

[0086] FIGS. 5A and 5B illustrate configurations of waveguide holography display systems which mitigate the effect of different pupil replication densities at different fields of view (FoVs) as illustrated in FIG. 4A, according to various examples.

[0087] In both FIGS. 5A and 5B, either (i) a complex SLM or (ii) a combination of a binary amplitude mask with a phase SLM may be used to control pupil density per FoV, which enhances uniformity. Accordingly, the terms “C / M+P SLM 510A,” “C / M+P SLM 510B,” and / or “C / M+P SLM 510A / B” may be used herein to refer to those two different possibilities in FIGS. 5A and 5B. In either case (i.e. , when the SLM is either a (i) complex SLM or (ii) a phase SLM with a binary amplitude mask), the C / M+P SLM 510A / B in FIGS. 5A and / or 5B may project modulated light in on / off pattern scans. In some examples, the “on” or “off” may simply refer to the modulated light being projected or not projected; in other examples, the “on” or “off” may refer to changes in amplitude, phase, modulation, and / or any other possible quality of the modulated light projected by the SLM.

[0088] In both FIGS. 5A and 5B, the C / M+P SLM 510A / B projects modulated light 515A / B consisting of three different on / off scans, into a waveguide 520A / B which has an in-coupling grating 521A / B which sends the input light through the interior of the waveguide 520A / B, where an out-coupling grating 523A / B projects the light towards a user’s eye 550A / B. In some examples, the in-coupling grating 521 A / B may be disposed on the other side of the waveguide 520A / B or integrated inside thewaveguide 520A / B, and / or may be functionally distributed among a number of gratings, and may include diffractive, reflective, geometric, etc., gratings. Similarly, the out-coupling grating 523A / B may be disposed in any suitable location, and / or may be functionally distributed among a number of gratings, and may include diffractive, reflective, geometric, etc., gratings. Similarly, the C / M+P SLM 510A / B may be disposed in other locations relative to the waveguide 520A / B, and / or functionally integrated into another component, and / or functionally distributed among multiple components, as would be understood by one of ordinary skill in the art. The C / M+P SLM 510A / B may be communicatively connected to, and / or under the control of, a controller 580A / B, and the controller 580A / B may be communicatively connected to, and / or controlling, other components in the near-eye display system (e.g., one or more laser sources, projectors, active polarizers, filters, etc.). The controller 580A / B may include a processor 583A / B and a memory 585A / B which may store instructions executable by the processor 583A / B to perform any of the methods described herein.

[0089] In FIG. 5A, three different on / off scan patterns (Scan 1 , Scan 2, and Scan 3) are projected by the C / M+P SLM 510A, where each scan produces a diagonal column of eyeboxes which are projected towards the user’s eye 550A. More specifically, eyeboxes 541 A resulting from Scan 1 , eyeboxes 543A resulting from Scan 2, and eyeboxes 545A resulting from Scan 3. As indicated by dotted box 530A, the focus directly in view of the user’s eye 550A contains various on / off scan patterns.

[0090] In FIG. 5B, three different on / off scan patterns (Scan 1 , Scan 2, and Scan 3) are projected by the C / M+P SLM 510B, where each scan produces a diagonal column of eyeboxes which are projected towards the user’s eye 550B. More specifically, eyeboxes 541 B resulting from Scan 1 , eyeboxes 543B resulting from Scan 2, and eyeboxes 545B resulting from Scan 3. As indicated by dotted box 530B, the focus directly in view of the user’s eye 550B contains various on / off scan patterns.

[0091] Holographic projection refers to a projection module that modulates the wavefront of light in principle of holographic display. Holographic projection can enable various advantages over traditional projection modules for waveguide displays such as improved uniformity in the eyebox domain and / or the FoV domain, improved resolution, improved efficiency, improved dynamic range. For example, a complex image displayed on the SLM may be optimized targeting better uniformity in both FoV and eyebox domains. With eye tracking, optimization performance may be even more enhanced. Resolution may be enhanced by controlling the wavefront of light. Higherdynamic range may be achieved by “code” the light re-distribution. Using the same principle of higher dynamic range, most of the light may be utilized without blocking, and thus improved light efficiency may be achieved.

[0092] FIGS. 6A through 6E are block diagrams of waveguide holography systems illustrating various configurations of holographic projection modules for projecting a two-dimensional (2D) hologram substantially directly into a waveguide display, according to various examples. In each of FIGS. 6A-6E, an augmented reality I virtual reality (AR / VR) near-eye display device may include: a display system to render AR / VR content having a waveguide display and a holographic two-dimensional (2D) projection module, an eye tracking system, and a controller to manage the display system and the eye tracking system. In some examples, the holographic 2D projection module may employ an SLM illuminated by a planar wavefront.

[0093] In some examples, the projected wavefront may be modulated to achieve various improvements in AR / VR waveguide displays using the principle of holographic display. Instead of an image, a 2D hologram may be projected into the waveguide allowing control of exit-pupil size, image resolution, dynamic range, and uniformity of image.

[0094] In some examples, temporal multiplexing (temporally combining multiple frames displayed from the SLM) may be used to reduce speckle noise, to increase the field of view, or to increase uniformity in eye box.

[0095] FIG. 6A shows a first configuration of a holographic projection module for projecting a 2D hologram substantially directly into a waveguide display according to some examples. In the configuration shown in FIG. 6A, the holographic projection module includes an SLM 610A illuminated by a planar wavefront (not shown), a projection lens 613A, a high-order filter 617A, and a waveguide 620A. The projection lens 613A may be disposed anywhere between the SLM 610A and the waveguide 620A, as indicated by the two-headed vertical arrow in FIG. 6A. In some examples, the projection lens 613A may be movable within the space between the SLM 610A and the waveguide 620A. The high-order filter 617A provides filtering in the Fourier domain and forms an aperture (in the Fourier domain), which is controllable by a phase pattern displayed on the SLM 610A. The SLM 610A may be communicatively connected to, and / or under the control of, a controller 680A, and the controller 680A may be communicatively connected to, and / or controlling, other components in the near-eye display system (e.g., the movement of the projection lens 613A in someexamples, one or more laser sources for the SLM 61 OA, projectors, active polarizers, filters, etc.). The controller 680A may include a processor 683A and a memory 685A which may store instructions executable by the processor 683A to perform any of the methods described herein.

[0096] In some examples, the projection lens 613A may be excluded, making the holographic projection module a direct holographic projection module. In other examples, the projection lens 613A may be positioned at any suitable location between the SLM 610A and the high-order filter 617A. In further examples, the high- order filter 617A may be an angular filter to reduce / remove noise such as high-order noise or any unwanted angular components of light that degrade the image, typically generated from high-order diffraction or direct reflection, or undiffracted light.

[0097] FIG. 6B shows a second configuration of a holographic projection module for projecting a 2D hologram substantially directly into a waveguide display according to some examples. In the configuration shown in FIG. 6B, the holographic projection module includes an SLM 61 OB illuminated by a planar wavefront (not shown), a projection lens 613B, a half-band filter 618B, and a waveguide 620B. The half-band filter 618B may form an aperture (in Fourier domain), which is controllable by a phase pattern displayed on the SLM 61 OB. The half-band filter 618B may also block DC order noise (if it exists). As indicated by the two-headed vertical arrow in FIG. 6B, the projection lens 613B may be disposed anywhere between the SLM 61 OB and the waveguide 620B and, in some examples, may be movable within the space between the SLM 61 OB and waveguide 620B. The SLM 61 OB may be communicatively connected to, and / or under the control of, a controller 680B, and the controller 680B may be communicatively connected to, and / or controlling, other components in the near-eye display system (e.g., the movement of the projection lens 613B in some examples, one or more laser sources for the SLM 61 OB, the aperture formed by the half-band filter 618B by controlling the phase pattern displayed on the SLM 61 OB, active polarizers, filters, etc.). The controller 680B may include a processor 683B and a memory 685B which may store instructions executable by the processor 683B to perform any of the methods described herein.

[0098] FIG. 6C shows a third configuration of a holographic projection module for projecting a 2D hologram substantially directly into a waveguide display according to some examples. In the configuration shown in FIG. 6C, the projection module includes an SLM 610C which may be illuminated by a planar wavefront (not shown),and no projection lens so that the SLM 61 OC projects patterned light 615C directly into a waveguide 620C. In the lens-less projection configuration of FIG. 6C, a direct-view SLM may be used as the SLM 61 OC. In this example configuration, the displayed image on the panel is in a Fourier domain of the perceived image by the user. The SLM 61 OC may be communicatively connected to, and / or under the control of, a controller 680C, and the controller 680C may be communicatively connected to, and / or controlling, other components in the near-eye display system (e.g., the one or more laser sources for the SLM 61 OC, any other active components, etc.). The controller 680C may include a processor 683C and a memory 685C which may store instructions executable by the processor 683C to perform any of the methods described herein.

[0099] FIG. 6D shows a fourth configuration of a holographic projection module for projecting a 2D hologram substantially directly into a waveguide display according to some examples. In the configuration shown in FIG. 6D, the holographic projection module includes two SLMs, i.e. , SLM1 611 D and SLM2 612D, with the first SLM, SLM1 611 D, which may be illuminated with a planar wavefront (not shown), no projection lens, and the light is projected through the second SLM, SLM2 612D, to project patterned light 615D directly into a waveguide 620D. In this example configuration, the displayed image on the panel is in a Fourier domain of the perceived image by the user. In some examples, a complex wavefront modulation SLM may also be used. The SLM1 611 D and / or SLM2 612D may be communicatively connected to, and / or under the control of, a controller 680D, and the controller 680D may be communicatively connected to, and / or controlling, other components in the near-eye display system (e.g., the one or more laser sources for the SLM1 611 D, any other active components, etc.). The controller 680D may include a processor 683D and a memory 685D which may store instructions executable by the processor 683D to perform any of the methods described herein.

[0100] FIG. 6E shows a fifth configuration of a holographic projection module for projecting a 2D hologram substantially directly into a waveguide display according to some examples. In the configuration shown in FIG. 6E, the holographic projection module includes two SLMs, i.e., SLM1 611 E and SLM2 612E, with the first SLM, SLM1 611 E, illuminated with a plane wavefront, no projection lens, and the light is projected through the second SLM, SLM2612E, to project patterned light 615E directly into a waveguide 620E. As shown in FIG. 6E, the 2 SLMs in this example configuration, SLM1 611 E and SLM2612E, are tilted with respect to the planar surfaceof the waveguide 620E, which may assist in filtering out noise. In some examples, the tilt of the 2 SLMs, SLM1 611 E and SLM2612E, may be controllable to, e.g., adaptively filter noise. The SLM1 611 E and / or SLM2 612E may be communicatively connected to, and / or under the control of, a controller 680E, and the controller 680E may be communicatively connected to, and / or controlling, other components in the near-eye display system (e.g., the one or more laser sources for the SLM1 611 E, the tilt of the 2 SLMs in some examples, any other active components, etc.). The controller 680E may include a processor 683E and a memory 685E which may store instructions executable by the processor 683E to perform any of the methods described herein.

[0101] FIGS. 7 and 8 illustrate different configurations of a compact foveated 2D projection module for a waveguide display, according to some examples. In the foveated schemes shown in FIGS. 7 and 8, a switchable lens may be used (such as, e.g., a Pancharatnam Berry Phase (PBP) lens) with a switchable half plate, both or either of which may be electrically / electronically controlled. FIG. 7 shows a foveated 2D compact projection module with a thin angular filter. FIG. 8 shows a maximum stretch compact foveated 2D projection module. Besides PBP lenses, other optical elements such as a liquid lens or a focus tunable liquid crystal (LC) lens may be used as the switchable lens. In FIGS. 7 and 8, the light may be projected out of the waveguide towards the translating pupil iris, lens, and camera as shown; in other examples, the light may be projected out towards a user’s eye.

[0102] In FIG. 7, a laser source 705 projects light onto a collimation lens 707, which collimates the light before it is reflected by a beamsplitter (BS) 709 to an SLM 710 which modulates the light with a pattern and projects the patterned light back through a polarizer 711 , a holographic optical element (HOE) / film stack angular filter 712, and the BS 709, to a projection lens 715 and a switchable lens 717 which projects the light into a right-handed waveguide 720. One or more components in the holographic projection module of FIG. 7, such as, for example, the laser source 705, the SLM 710, the HOE / film stack angular filter 712, and the switchable lens 717, may be communicatively connected to, and / or under the control of, a controller 780, and the controller 780 may be communicatively connected to, and / or controlling, other components in the near-eye display system (e.g., the polarizer 711 in some examples, the projection lens 715 in some examples, any other active components, etc.). The controller 780 may include a processor 783 and a memory 785 which may store instructions executable by the processor 783 to perform any of the methods describedherein.

[0103] n FIG. 7, the light may be projected out through a translating pupil iris 762 to a lens 764 for a camera 766. In some examples, the light may be projected out to a user’s eye.

[0104] In FIG. 8, a laser source 805 projects light which is received by an SLM 810 which modulates the light with a pattern and projects the patterned light back through a holographic optical element (HOE)Zfilm stack angular filter 812 to a projection lens 815 and a switchable lens 817 which projects the light into a liquid crystal (LC) steering lens 819, which steers the light into a right-handed high FoV waveguide 820. One or more components in the holographic projection module of FIG. 8, such as, for example, the laser source 805, the SLM 810, the HOE / film stack angular filter 812, the switchable lens 817, and the LC steering lens 819 may be communicatively connected to, and / or under the control of, a controller 880, and the controller 880 may be communicatively connected to, and / or controlling, other components in the near-eye display system (e.g., the projection lens 815 in some examples, any other active components, etc.). The controller 880 may include a processor 883 and a memory 885 which may store instructions executable by the processor 883 to perform any of the methods described herein.

[0105] In FIG. 8, the light may be projected out through a translating pupil iris 862 to a lens 864 for a camera 866. In some examples, the light may be projected out to a user’s eye.

[0106] In some examples, the controllers 480 / 580 / 680 / 780 / 880 and / or other components shown in any of FIGS. 4A, 5A-5B, 6A-6E, 7, and / or 8, respectively, may be integrated into and / or employed as a component in other systems and / or for other functionalities of a near-eye display device, as would be understood by one of ordinary skill in the art. For instance, the holographic projection modules and / or any of their constituent components in any of FIGS. 4A, 5A-5B, 6A-6E, 7, and / or 8 may be integrated into, collocated with, and / or implemented as part of, the eye tracking system of the near-eye display device (such as, e.g., the eye tracking module 130 and / or the eye tracking unit 118 in FIG. 1 or the controller(s) 317 in FIG. 3).

[0107] As shown in FIGS. 4A, 5A-5B, 6A-6E, 7, and / or 8, the controllers 480A, 580A / B, 680A-E, 780, and / or 880, respectively, may include the processors 483A, 583A / B, 683A-E, 783, and / or 883, respectively, and the memories 485A, 585A / B, 685A-E, 785, and / or 885, respectively. In some examples, the controller 480A,580A / B, 680A-E, 780, and / or 880 may be implemented as hardware, software, and / or a combination of hardware and software in the near-eye display device. In some examples, the controller 480A, 580A / B, 680A-E, 780, and / or 880 may be implemented, in whole or in part, by at least one of any type of application, program, library, script, task, service, process, or any type or form of executable instructions executed on hardware such as circuitry that may include digital and / or analog elements (e.g., one or more transistors, logic gates, registers, memory devices, resistive elements, conductive elements, capacitive elements, and / or the like, as would be understood by one of ordinary skill in the art). In some examples, the processor 483A, 583A / B, 683A- E, 783, and / or 883 may be implemented with a general purpose single- and / or multichip processor, a single- and / or multi-core processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, and / or any combination thereof suitable to perform the functions described herein. A general purpose processor may be any conventional processor, microprocessor, controller, microcontroller, and / or state machine. In some examples, the memory 485A, 585A / B, 685A-E, 785, and / or 885 may be implemented by one or more components (e.g., random access memory (RAM), read-only memory (ROM), flash or solid state memory, hard disk storage, etc.) for storing data and / or computer-executable instructions for completing and / or facilitating the processing and storage functions described herein. In such examples, the memory 485A, 585A / B, 685A-E, 785, and / or 885 may be volatile and / or non-volatile memory, and may include database components, object code components, script components, or any other type of information structure suitable for implementing the various activities and storage functions described herein.

[0108] According to examples, a method of providing holographic 2D image projection in an augmented reality / virtual reality (ARA / R) system is described herein. A system of providing holographic 2D image projection in an AR / VR system is also described herein. A non-transitory computer-readable storage medium may have an executable stored thereon, which when executed instructs a processor to perform the methods described herein.

[0109] In the foregoing description, various examples are described, including devices, systems, methods, and the like. For the purposes of explanation, specific details are set forth in order to provide a thorough understanding of examples of thedisclosure. However, it will be apparent that various examples may be practiced without these specific details. For example, devices, systems, structures, assemblies, methods, and other components may be shown as components in block diagram form in order not to obscure the examples in unnecessary detail. In other instances, well- known devices, processes, systems, structures, and techniques may be shown without necessary detail in order to avoid obscuring the examples.

[0110] The figures and description are not intended to be restrictive. The terms and expressions that have been employed in this disclosure are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof. The word "example" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or design described herein as "example1is not necessarily to be construed as preferred or advantageous over other embodiments or designs.

[0111] Although the methods and systems as described herein may be directed mainly to digital content, such as videos or interactive media, it should be appreciated that the methods and systems as described herein may be used for other types of content or scenarios as well. Other applications or uses of the methods and systems as described herein may also include social networking, marketing, content-based recommendation engines, and / or other types of knowledge or data-driven systems.

Claims

CLAIMS:1 . An augmented reality I virtual reality (ARA / R) near-eye display device, comprising: a display system to render ARA / R content comprising: a waveguide display; and a holographic two-dimensional (2D) projection module employing at least one spatial light modulator (SLM), wherein the at least one SLM is illuminated by a planar wavefront; an eye tracking system; and a controller to manage the display system and the eye tracking system.

2. The ARA / R display device of claim 1 , wherein the holographic 2D projection module further comprises: a projection lens.

3. The ARA / R display device of claim 1 or 2, wherein the holographic 2D projection module further comprises: a high-order filter.

4. The ARA / R display device according to any of the preceding claims, wherein the holographic 2D projection module further comprises: a half-band filter.

5. The ARA / R display device according to any of the preceding claims, wherein the at least one SLM comprises a first SLM and a second SLM, wherein the first SLM and the second SLM are stacked.

6. The ARA / R display device of claim 5, wherein the first SLM and the second SLM are tiltable to provide angular filtering.

7. The ARA / R display device according to any of the preceding claims, wherein the at least one SLM is a complex wavefront modulation SLM.

8. A near-eye display device, comprising: a waveguide display to display augmented reality I virtual reality (ARA / R) content to a user; and a holographic projection module to generate and project a two-dimensional (2D) image into the waveguide display for the waveguide display to form three-dimensional (3D) content for the user, wherein the holographic projection module comprises: a spatial light modulator (SLM) to be illuminated by a planarwavefront and then to modulate and to project the modulated light with an on / off pattern such that multiple eyeboxes of varying densities are formed.

9. The near-eye display device of claim 8, wherein the SLM is a complex wavefront modulation SLM; and / or preferably wherein the SLM is a phase SLM with a binary amplitude mask.

10. The near-eye display device of claim 8 or 9, wherein the holographic 2D projection module further comprises: a controller to control the SLM to modulate and project on / off patterned light; and / or preferably wherein the waveguide display comprises: an in-coupling grating to receive the modulated light from the SLM; and an out-coupling grating to project the modulated light out of the waveguide display to an eye of the user.11 . A near-eye display device, comprising: a waveguide display to display augmented reality I virtual reality (AR / VR) content to a user; and a holographic projection module to generate and project a two-dimensional (2D) image into the waveguide display for the waveguide display to form three-dimensional (3D) content for the user, wherein the holographic projection module comprises: a spatial light modulator (SLM) to be illuminated by a planar wavefront and then to modulate and to project the patterned light planar wavefront; a holographic optical element (HOE) to receive and project the patterned light planar wavefront; and a switchable lens to receive the patterned light planar wavefront from the HOE and project the 2D image into the waveguide display.

12. The near-eye display device of claim 11 , wherein the switchable lens is a Pancharatnam Berry Phase (PBP) lens.

13. The near-eye display device of claim 11 or 12, wherein the switchable lens is at least one of a liquid lens or a focus tunable liquid crystal (LC) lens; and / or preferably wherein the HOE is a film stack angular filter.

14. The near-eye display device according to any of the claims 11 to 13, whereinthe holographic projection module further comprises: a liquid crystal (LC) steering lens; and / or preferably wherein the waveguide display comprises: a right-handed waveguide.

15. The near-eye display device according to any of the claims 11 to 14, wherein the holographic projection module further comprises: a laser source to provide the planar wavefront to illuminate the SLM; and / or preferably the near-eye display device further comprising: a controller to control the SLM, the HOE, and the switchable lens.

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