Combined eye tracking SMI sensor and quasi-led vcsel projector

Abstract

Systems, devices, and methods for an integrated circuit having both a self mixing interferometer (SMI) eye tracking sensor and a vertical cavity self emitting laser (VCSEL) eye tracking pattern projector are described, which may be used in a near-eye display device. In one aspect, the SMI eye tracking sensor projects and receives light from a user's eye to perform non-image-based eye tracking, while the VCSEL eye tracking pattern projector projects a pattern onto the user's eye, and light of the projected pattern reflected by the user's eye is used to perform image-based eye tracking. The light beam projected by the VCSEL projector may be similar in, e.g., breadth to an LED and thus may be called "quasi-LED." In another aspect, eye tracking methods using the combined SMI sensor / quasi-LED VCSEL projector are described. In yet another aspect, methods of manufacturing the combined SMI sensor / quasi-LED VCSEL projector are described.

Description

COMBINED EYE TRACKING SMI SENSOR AND QUASI-LED VCSEL PROJECTORCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims benefit of and priority to U.S. provisional patent application Ser. No. 63 / 617,566 filed January 4, 2024.TECHNICAL FIELD

[0002] This patent application relates generally to eye tracking, and in particular to an integrated circuit having both a self mixing interferometer (SMI) sensor and a vertical cavity self emitting laser (VCSEL) quasi-light emitting diode (LED) pattern projector to be used for eye tracking in a near-eye display device.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 other content within and / or associated with a real and / or virtual environment (e.g., a “metaverse”) have become more widely available to consumers. This interactive content includes simulated three-dimensional (3D) environments, objects, images, representations, art and the like.

[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 near-eye display device, such as, e.g., a wearable headset or head-mounted display (HMD) device, a wearable eyewear, or eyeglasses (e.g., “smartglasses”). In some examples, the head-mounted display (HMD) device may project or direct light to may 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 augmented reality (AR) system, a user may view both images of virtual objects (e.g., computer-generated images (CGIs)) and the surrounding environment. Head-mounted display (HMD) devices may also present interactive content, where a user’s (wearer’s) gaze may be used as input for the interactive content.

[0005] Wearable display devices, such as virtual reality (VR), augmented reality (AR), and / or mixed reality (MR) glasses, may require increasingly complex and intricate lens assembly structures, as well as increasingly complex and intricate electronic structures, etc., thereby complicating, inter alia, the manufacturing process. Moreover, the need for both electronics and optics to have a relatively small size and negligible weight for portability and user comfort, as well as the ability to operate in a wide variety of environments, produces a host of challenges and competing concerns, in areas such as, for example, eye tracking. SUMMARY

[0006] According to a first aspect, there is provided an integrated circuit for a near-eye display device, comprising: a self mixing interferometer (SMI) eye tracking sensor to: project a beam of light onto an eye, receive first reflected light from the eye by the beam of light, modulate the first reflected light, and provide an electrical signal corresponding to the modulated light, wherein non-image-based eye tracking is performed based on the electrical signal; and a vertical cavity self emitting laser (VCSEL) eye tracking pattern projector to: project a pattern onto the eye, wherein image-based eye tracking is performed based on second reflected light from the eye by the pattern projected by the VCSEL eye tracking pattern projector.

[0007] The SMI eye tracking sensor may comprise: a top reflector layer; an optical cavity; a middle reflector layer; a photodetector (PD) layer to receive the modulated light and provide the electrical signal corresponding to the modulated light; and a bottom reflector layer.

[0008] The PD layer in the S I eye tracking sensor may comprise at least one of a photodetector or a photodiode.

[0009] The VCSEL eye tracking pattern projector may comprise: a top reflector layer; an optical cavity; and a middle reflector layer.

[0010] The optical cavity of the VCSEL eye tracking pattern projector may comprise: a laser cavity operable to project a wide emission beam.

[0011] The laser cavity may comprise: a tapered laser cavity.

[0012] The VCSEL eye tracking pattern projector may further comprise: a micromechanical system (MEMS) to alter a shape of the laser cavity.

[0013] The bottom reflector layer may comprise a distributed Bragg reflector (DBR).

[0014] The DBR may comprise a chirped distributed Bragg reflector (DBR).

[0015] The VCSEL eye tracking pattern projector may comprise: an increased diameter aperture to project a wide emission beam.

[0016] The VCSEL eye tracking pattern projector may comprise: a metasurface to project a wide emission beam.

[0017] The integrated circuit may be disposed within a lens of the near-eye display device.

[0018] The integrated circuit may be disposed on a frame of the near-eye display device.

[0019] According to a second aspect, there is provided a method of eye tracking in a near-eye display device, comprising: projecting, by a self mixing interferometer (SMI) eye tracking sensor in an integrated circuit (IC), a beam of light towards an eye of a user of the near-eye display device; projecting, by a vertical cavity self emitting laser (VCSEL) eye tracking pattern projector in the integrated circuit (IC), a pattern of light towards the eye of the user; receiving and modulating, by the self mixing interferometer (SMI) eye trackingsensor, first reflected light from the eye of the user by the beam of light projected by the self mixing interferometer (SMI) eye tracking sensor; providing, by the self mixing interferometer (SMI) eye tracking sensor, an electrical signal corresponding to the received and modulated light; receiving, by an eye tracking camera, second reflected light from the eye of the user by the pattern of light projected by the vertical cavity self emitting laser (VCSEL) eye tracking pattern projector; providing, by the eye tracking camera, data corresponding to the received second reflected light; performing image-based eye tracking based on the data provided by the eye tracking camera; and performing non-image eye tracking based on the electrical signal provided by the self mixing interferometer (SMI) eye tracking sensor.

[0020] The method may further comprise: performing eye tracking by integrating the image-based eye tracking and the non-image-based eye tracking.

[0021] According to a third aspect, there is provided a method of manufacturing an eye tracking sensor for a near-eye display device, comprising: providing a substrate; providing a bottom reflector layer on the substrate; providing a photodetector (PD) layer above the bottom reflector layer; providing a middle reflector layer above the PD layer; providing one or more layers above the middle reflector layer to provide a first optical cavity on a first portion and a second optical cavity on a second portion; providing a top reflector layer above the one or more layers having the first optical cavity on the first portion and the second optical cavity on the second portion; and etching away at least a portion of the top reflector layer on the second portion; wherein the bottom reflector layer, the PD layer, the middle reflector layer, the first optical cavity, and the top reflector layer on the first portion comprise a self mixing interferometer (SMI); and wherein the middle reflector layer, the second optical cavity, and the etched top reflector layer on the second portion comprise a vertical cavity self emitting laser (VCSEL).

[0022] The method may further comprise: providing a protective coating on the first portion before the step of etching away on the second portion.

[0023] The second optical cavity may comprise a laser cavity operable to project a wide emission beam.

[0024] The step of providing one or more layers above the middle reflector layer to provide a first optical cavity on a first portion and a second optical cavity on a second portion may comprise: providing the second optical cavity as a tapered laser cavity.

[0025] The method may further comprise: providing a micromechanical system (MEMS) to alter a shape of the laser cavity.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 andmethods illustrated in the figures can be employed without departing from the principles described herein.

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

[0028] Figures 2A and 2B illustrate a front prospective view and a back prospective view, respectively, of a near-eye display device in the form of a head-mounted display (HMD) device to which examples of the present disclosure may be applied.

[0029] Figures 3A and 3B illustrate a perspective view and a top view, respectively, of a near-eye display device in the form of a pair of glasses to which examples of the present disclosure may be applied.

[0030] Figure 4 is a simplified block diagram of a cross-sectional view of a combined Self-Mixing Interferometer (SMI) eye tracking sensor and quasi-Light Emitting Diode (LED) Vertical Cavity Surface Emitting Laser (VCSEL) eye tracking pattern projector in a chip, according to an example.

[0031] Figure 5 is a simplified block diagram of a cross-sectional view of a combined Self-Mixing Interferometer (SMI) eye tracking sensor and quasi-Light Emitting Diode (LED) Vertical Cavity Surface Emitting Laser (VCSEL) eye tracking pattern projector chip, according to an example.

[0032] Figure 6 a perspective view of a near-eye display device in the form of a pair of glasses having an array of combined Self-Mixing Interferometer (SMI) eye tracking sensor and quasi-Light Emitting Diode (LED) Vertical Cavity Surface Emitting Laser (VCSEL) eye tracking pattern projector chips, according to an example.

[0033] Figure 7 is a planar view of a combined Self-Mixing Interferometer (SMI) eye tracking sensor and quasi-Light Emitting Diode (LED) Vertical Cavity Surface Emitting Laser (VCSEL) eye tracking pattern projector chip, according to an example.

[0034] Figure 8 is a flowchart illustrating a method for eye tracking using a combined Self-Mixing Interferometer (SMI) eye tracking sensor and quasi-Light Emitting Diode (LED) Vertical Cavity Surface Emitting Laser (VCSEL) eye tracking pattern projector chip, according to an example.

[0035] Figure 9 is a flowchart illustrating a method for manufacturing a combined SelfMixing Interferometer (SMI) eye tracking sensor and quasi-Light Emitting Diode (LED) Vertical Cavity Surface Emitting Laser (VCSEL) eye tracking pattern projector chip which may be used in a near-eye display device according to an example.DETAILED DESCRIPTION

[0036] 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 bereadily apparent, however, that the present application may be practiced without limitation to these specific details. In other instances, 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.

[0037] As used herein, a “near-eye display device” may refer to any display device (e.g., an optical device) that may be in close proximity to a user’s eye. Accordingly, a near- eye display device may be a head-mounted display (HMD) device, such as a wearable eyewear, a wearable headset, and / or “smartglasses,” which may be used for interacting with virtual reality (VR), augmented reality (AR), and / or mixed reality (MR) environments, or any environment of real and virtual elements, such as a “metaverse.” As used herein, a “wearable device” may refer to any portable electronic device that may be worn on any body part of a user and used to present audio and / or video content, control other devices, monitor bodily functions, and perform similar actions. As used herein, a “user" may refer to a user or wearer of a “near-eye display device” and / or a “wearable display.”

[0038] As mentioned above, it may be beneficial for the various components in any near-eye display device to have a relatively small size and negligible weight for portability and user comfort. Accordingly, it may be desirable to reduce the size, location, power / energy, and other requirements of the eye tracking system in any near-eye display device to, for example, increase the overall efficiency of the near-eye display device.

[0039] According to examples of the present disclosure, a direct optical eye tracking sensor system may be provided on a chip, upon which both a Self-Mixing Interferometer (SMI) sensor and a Vertical-Cavity Surface Emitting Laser (VCSEL) acting as an illumination source are disposed. In some examples, the direct optical eye tracking sensor system may be a combination of individual Vertical-Cavity Surface Emitting Laser (VCSEL) emitters with external photodiodes and external signal amplifiers; in other examples, the direct optical eye tracking sensor system may be a combination of individual Vertical-Cavity Surface Emitting Laser (VCSEL) emitters with integrated photodiodes and internal or external signal amplifiers.

[0040] According to examples of the present disclosure, a combined Self-Mixing Interferometer (SMI) eye tracking sensor and a Vertical-Cavity Surface Emitting Laser (VCSEL) eye tracking pattern projector chip may be provided. In some examples, the Vertical- Cavity Surface Emitting Laser (VCSEL) eye tracking pattern projector may be suitably modified to emulate a Light Emitting Diode (LED) emission pattern by projecting a wide emission beam which may be used to illuminate a user’s eye for camera-based eye tracking. To achieve this, the size or shape of the emitting aperture of the Vertical-Cavity SurfaceEmitting Laser (VCSEL) eye tracking pattern projector may be modified; in some examples, the size or shape of the laser cavity of the Vertical-Cavity Surface Emitting Laser (VCSEL) eye tracking pattern projector may be modified; in some examples, one or more of the reflector layers of the Vertical-Cavity Surface Emitting Laser (VCSEL) eye tracking pattern projector may be modified; and, in some examples, a metasurface may be disposed on top of the Vertical-Cavity Surface Emitting Laser (VCSEL) eye tracking pattern projector. In some examples, the top reflector layer of the Vertical-Cavity Surface Emitting Laser (VCSEL) eye tracking pattern projector may be cut through during the fabrication process to provide a hole which causes the Vertical-Cavity Surface Emitting Laser (VCSEL) eye tracking pattern projector, when activated, to provide a wide beam emission similar to a Light Emitting Diode (LED).

[0041] According to examples of the present disclosure, the Self-Mixing Interferometer (SMI) eye tracking sensor on the combined chip may enable non-image-based eye tracking, while the Vertical-Cavity Surface Emitting Laser (VCSEL) eye tracking pattern projector on the combined chip may enable camera-based or image-based eye tracking. In some examples, the combined chip may include two different Vertical-Cavity Surface Emitting Lasers (VCSELs) with two different output light emission cones. In some examples, the Vertical-Cavity Surface Emitting Laser (VCSEL) eye tracking pattern projector on the combined chip may be operable to project a wide emission beam having a higher divergence angle to project patterns which emulate patterns projected by Light Emitting Diode (LED) pattern projectors. In some examples, the combined Self-Mixing Interferometer (SMI) eye tracking sensor and a Vertical- Cavity Surface Emitting Laser (VCSEL) eye tracking pattern projector chip may enable both eye gaze-based eye tracking and depth-velocity-based eye tracking.

[0042] According to examples of the present disclosure, a combined Self-Mixing Interferometer (SMI) eye tracking sensor and a Vertical-Cavity Surface Emitting Laser (VCSEL) eye tracking pattern projector chip may be able to increase the overall accuracy, speed, and other requirements of an eye tracking system in any near-eye display device, as well as reducing the overall footprint and power consumption of the eye tracking system. While some advantages and benefits of the present disclosure are discussed herein, there are additional benefits and advantages which would be apparent to one of ordinary skill in the art.

[0043] As discussed above, in examples according to the present disclosure, the Vertical-Cavity Surface Emitting Laser (VCSEL) eye tracking pattern projector may be suitably modified to project a wide emission beam, thereby appearing more like a light beam projected by a Light Emitting Diode (LED) than the relatively focused / tight light beam typically projected by lasers like the Vertical-Cavity Surface Emitting Laser (VCSEL). Accordingly, the term “quasi-LED” may be used herein when referring to the Vertical-Cavity Surface Emitting Laser (VCSEL) eye tracking pattern projector to indicate this difference in light projected therefrom,and does not in any way indicate a technical and / or electrical / electronic similarity with a Light Emitting Diode (LED).

[0044] Figure 1 illustrates a block diagram of an artificial reality system environment including a near-eye display device, according to an example. As used herein, a “near-eye display device” 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 (VR), augmented reality (AR), and / or mixed reality (MR). As used herein a “user” may refer to a user or wearer of a “near-eye display device.”

[0045] As shown in Figure 1 , an artificial reality system environment 100 may include a near-eye display device 120, an optional external imaging device 150, and an optional input / output interface 140, each of which may be coupled to an optional console 110. The optional console 110 may be optional in some instances where functions of the optional console 1 10 may be integrated into the near-eye display device 120. In some examples, the near-eye display device 120 may be implemented in any suitable form-factor, including a head-mounted display (HMD), a pair of glasses, or other similar wearable eyewear or device. In some examples, the near-eye display device 120 may include one or more rigid 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. Specific examples of implementations of the near-eye display device 120 are described further below with respect to Figures 2A-2B and 3A-3B.

[0046] In some examples, the near-eye display device 120 may present content to a user, including, for example, audio / visual content, such as, e.g., virtual reality (VR), augmented reality (AR), and / or mixed reality (MR) content. In augmented reality (AR) and / or mixed reality (MR) examples, the near-eye display device 120 may combine images (and / or a see-through view) of a physical, real-world environment external to the near-eye display device 120 and artificial reality / digital content (e.g., computer-generated images, video, sound, etc.) to present an augmented reality (AR) or mixed reality (MR) environment for the user.

[0047] As shown in Figure 1 , the near-eye display device 120 may include any one or more of one or more processors 121 , display electronics 122, display optics 124, one or more locators 126, one or more position sensors 128, an eye tracking unit 130, an inertial measurement unit (IMU) 132, a wireless communication sub-system 134, one or more outward projectors 172, and / or one or more inward projectors 173. In some examples, the near-eye display device 120 may include additional components; in other examples, the near-eye display device 120 may omit any one or more of the one or more locators 126, the one or more position sensors 128, the eye tracking unit 130, the inertial measurement unit (IMU) 132, thewireless communication sub-system 134, the one or more outward projectors 172, and / or the one or more inward projectors 173. As would be understood by one of ordinary skill in the art, various operational, electronic, communication (for, e.g., control signals), electrical and other such connections may or may not also be included between and among the components of the near-eye display device 120.

[0048] In some examples, the display electronics 122 may display or facilitate the display of images to the user according to data received from control electronics disposed in, for example, the near-eye display device 120, the optional console 110, the input / output interface 140, and / or a system connected by wireless or wired connection with the near-eye display device 120. In some examples, such electronics may include a virtual reality engine, such as, for example, the virtual reality engine 1 16 in the external console 1 10 described below, a virtual reality engine implemented, in part or in whole, in electronics in the near-eye display device 120, and / or a virtual reality engine implemented, in whole or in part, in an external system connected by the wireless communication subsystem 134, etc. In some examples, the display electronics 122 may include one or more display panels, and may include and / or be operationally connected to the display optics 124. In some examples, the display electronics may include one or more of a liquid crystal display (LCD) and / or a lightemitting diode (LED) and may include any number of pixels to emit light of a predominant color such as red, green, blue, white, oryellow. In some examples, the display electronics 122 may display a three-dimensional (3D) image, e.g., using stereoscopic effects produced by two- dimensional panels, to create a subjective perception of image depth.

[0049] In some examples, the display electronics 122 may include and / or be operationally connected to the one or more outward projectors 172 and / or the one or more inward projectors 173; in some examples, the eye tracking unit 130 may also include and / or be operationally connected to the one or more inward projectors 173. As indicated by the striped lined box in Figure 1 , there may be operational and / or other connections between and among the display electronics 122, the eye tracking unit 130, the one or more outward projectors 172, and / or the one or more inward projectors 173. As indicated above, such connections may also be included between and among these and other components of the near-eye display device 120; the possible connections indicated by the striped lined box in Figure 1 are shown herein as they are germane to examples of the present disclosure.

[0050] In some examples, the one or more inward projectors 173 may, under the control of the display electronics 122, form an image in angular domain for direct observation by a viewer’s eye through a pupil. In some examples, the same or different one or more inward projectors 173 may, under the control of the eye tracking unit 130, project a fringe or other pattern on the eye (such as the inward projectors 310 of Figures 3A and 3B discussed below). 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 examples where at least some of the one or more inward projectors 173 may be used to project a fringe pattern on the eye, reflections from the projected pattern on the eye may be captured by a camera and analyzed (e.g., by the eye tracking unit 130 and / or the eye tracking module 1 18 in the optional console 1 10) to determine a position of the eye (the pupil), a gaze, etc. In other examples, the eye tracking unit 130 may capture reflected radio waves emitted by a miniature radar unit. These data associated with the eye may be used to determine or predict eye position, orientation, movement, location, and / or gaze.

[0051] In some examples, the one or more outward projectors 172 may, under the control of the display electronics 122, project a fringe or other pattern on the external environment (such as the outward projectors 315 of Figures 3A and 3B). In examples where at least some of the one or more outward projectors 172 may be used to project a fringe pattern on the external environment, reflections from the projected pattern on the external environment may be captured by a camera and analyzed to determine a position of objects in the external environment, distances between the user and objects and / or surfaces of the external environment, etc.

[0052] In some examples, a location of any of the one or more inward projectors 173 and / or the one or more outward projectors 172 may be adjusted to enable any number of design modifications. For example, in some instances, the one or more inward projectors 173 may be disposed in the near-eye display device 120 in front of the user’s eye (e.g., “frontmounted” placement). In a front-mounted placement, in some examples, the one or more inward projectors 173 under control of the display electronics 122 may be located away from a user’s eyes (e.g., “world-side”). In some examples, the near-eye display device 120 may utilize a front-mounted placement to propagate light and project an image on the user’s eye(s).

[0053] In some examples, the one or more outward and / or inward projectors 172 and / or 173 may employ a controllable light source (e.g., a laser) and a microelectromechanical system (MEMS) beam scanner to create a light field from, for example, a collimated light beam. In some examples, the light source of the one or more projectors 172 and / or 173 may include one or more of a liquid crystal display (LCD), a light emitting diode (LED) or micro-light emitting diode (mLED), an organic light emitting diode (OLED), an inorganic light emitting diode (ILED), an active-matrix organic light emitting diode (AMOLED), a transparent organic light emitting diode (TLED), any other suitable light source, and / or any combination thereof. In some examples, the one or more projectors may comprise a single electronic display or multiple electronic displays (e.g., one for each eye of the user).

[0054] In some examples, the display optics 124 may project, direct, and / or otherwise display image content optically and / or magnify image light received from the one or more inward projectors 173 (and / or otherwise created by the display electronics 122), correct opticalerrors associated with image light created and / or received from the external environment, and / or present the (corrected) image light to a user of the near-eye display device 120. In some examples, the display optics 124 may include an optical element or any number of combinations of various optical elements as well as mechanical couplings to, for example, 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 include an aperture, a Fresnel lens, a refractive lens, a reflective mirror, a diffractive element, a waveguide, a filter, or any other optical element suitable for affecting and / or otherwise manipulating light emitted from the one or more inward projectors 173 (and / or otherwise created by the display electronics 122). 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.

[0055] In some examples, the display optics 124 may be used to combine the view of an environment external to the near-eye display device 120 and artificial reality content (e.g., computer-generated images) generated by, e.g., the virtual reality engine 1 16 in the console 1 10, and projected by, e.g., the one or more inward projectors 173 (and / or otherwise created by the display electronics 122). In such examples, the display optics 124 may augment images of a physical, real-world environment external to the near-eye display device 120 with generated and / or overlaid digital content (e.g., images, video, sound, etc.) projected by the one or more inward projectors 173 (and / or otherwise created by the display electronics 122) to present an augmented reality (AR) to a user.

[0056] In some examples, the display optics 124 may also be designed to correct one or more types of optical errors, such as two-dimensional optical errors, three-dimensional optical errors, or any combination thereof. Examples of two-dimensional errors may include barrel distortion, pincushion distortion, longitudinal chromatic aberration, and / or transverse chromatic aberration. Examples of three-dimensional errors may include spherical aberration, chromatic aberration field curvature, and astigmatism.

[0057] 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 device 120. In some examples, the optional console 1 10 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 reflector, a reflective marker, a type of light source that contrasts with an environment in which the near-eye display device 120 operates, or any combination thereof.

[0058] In some examples, the optional external imaging device 150 may include one or more cameras, one or more video cameras, any other device capable of capturing imagesincluding the one or more locators 126, or any combination thereof. The optional external imaging device 150 may detect light emitted or reflected from the one or more locators 126 in a field of view of the optional external imaging device 150.

[0059] In some examples, the one or more position sensors 128 may sense motion of the near-eye display device 120 and, in response, generate one or more measurement signals and / or data. 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.

[0060] In some examples, the inertial measurement unit (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 inertial measurement unit (IMU) 132, internal to the inertial measurement unit (IMU) 132, or any combination thereof. Based on the one or more measurement signals from the one or more position sensors 128, the inertial measurement unit (IMU) 132 may generate fast calibration data indicating an estimated position of the near- eye display device 120. Estimated positions may be of a reference point on the near-eye display device 120, and estimated positions may be, for example, relative to an initial position of the near-eye display device 120, relative to other objects in an external environment, relative to virtual objects in an artificial environment or augmented / mixed reality, etc., as would be understood by one of ordinary skill in the art. For example, the inertial measurement unit (IMU) 132 may integrate measurement signals received from accelerometers over time to estimate a velocity vector and integrate the velocity vector overtime to determine an estimated position of the near-eye display device 120. Alternatively, the inertial measurement unit (IMU) 132 may provide the sampled measurement signals to the optional console 110, which may determine the fast calibration data.

[0061] In some examples, the wireless communication subsystem 134 may include an ultra-wide band (UWB) transceiver. Ultra-wide band (UWB) wireless communication technology is used for short-range, fast, and secure data transmission environments. Ultrawide band (UWB) wireless communication technology provides high transmission speed, low power consumption, and large bandwidth, in addition to the ability to co-exist with other wireless transmission technologies. The ultra-wide band (UWB) transceiver may be used to detect another user (head-mounted display (HMD) device) within range of communication and within an angle-of-arrival (AoA), then establish line-of-sight (LoS) communication between the two users. The communication may be in audio mode only or in audio / video mode. In other examples, the ultra-wide band (UWB) transceiver may be used to detect the other user, but a different communication technology (transceiver) such as WiFi or Bluetooth Low Energy (BLE) may be used to facilitate the line-of-sight (LoS) communication. In some cases, multiplewireless communication transceivers may be available and one with lowest power consumption, highest communication quality (e.g., based on interfering signals), or user choice may be used. For example, the communication technology may be selected based on a lowest power consumption for a given range.

[0062] In some examples, the one or more processors 121 may be the control electronics (which may include, e.g., an operating system) forthe near-eye display device 120. The one or more processors 121 may be employed for controlling one or more of the display electronics 122, the display optics 124, the one or more locators 126, the one or more position sensors 128, the eye tracking unit 130, the inertial measurement unit (IMU) 132, the wireless communication sub-system 134, the one or more outward projectors 172, and / or the one or more inward projectors 173, according to the present disclosure. The one or more processors 121 may be implemented, in whole or in part, as a separate physical component in the near- eye display device 120, as distributed among and / or integrated into one or more components of the near-eye display device 120 (such as, e.g., the display electronics 122), and / or externally to near-eye display device 120, such as being implemented / integrated in, for example, the input / output interface 140 and / or the console 1 10 (e.g., the eye tracking module 1 18, the headset tracking module 1 14, the virtual reality engine 1 16, the application store 112, etc ), and / or in another external system connected by, for example, the wireless communication subsystem 134. In some examples, the one or more processors 121 of the near-eye display device 120 may receive input, store, and process data, and / or control the components of the near-eye display device 120 in accordance with received input and / or stored / processed data in order to maintain optimal operating conditions of one or more components in the near-eye display device 120.

[0063] In some examples, the one or more processors 121 , any control electronics, and / or any of the other components of the near-eye display device 120 may be implemented in and / or by any number of processors executing instructions stored on any number of non- transitory computer-readable storage media (not shown) disposed on / in and / or communicatively linked to the near-eye display device 120. The one or more processors 121 may include multiple processing units executing instructions in parallel. The non-transitory computer-readable storage medium / media 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 one or more processors 121 in the near-eye display device 120 may perform one or more functions; in some examples, one or more non-transitory computer-readable storage media in the near-eye display device 120 may store instructions that, when executed by the one or more processors 121 , cause the one or more processors 121 to perform any of the functions described herein and / or to control any of the components described herein. In some examples, functions such as those described below in reference tothe optional console 110 (e.g., eye tracking, headset tracking, and the generation of virtual reality images) may be performed by the one or more processors 121 integrated with and / or wired / wirelessly connected to the near-eye display device 120.

[0064] 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 and / or the near-eye display device 120. 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 and / or the near-eye display device 120, either or both of which may perform an action corresponding to the requested action.

[0065] In some examples, the optional console 110 may provide content to the near- eye display device 120 for presentation to the user in accordance with information received from one or more of the near-eye display device 120, the input / output interface 140, and / or the external imaging device 150. For example, as shown in the example of Figure 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. In some examples, the optional console 110 may include different or additional modules than those described herein, and the functions described further below may be distributed among the components of the optional console 110 in a different manner than is described here (or may be distributed, in part or whole, in one or more components in the near-eye display device 120). It should be appreciated that the optional console 110 may or may not be needed, or the optional console 110 may be integrated, in whole or in part, with the input / output interface 140 and / or the near- eye display device 120, or the optional console 110 may be separate from the input / output interface 140 and / orthe near-eye display device 120. 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 (including, for example, the application store 112).

[0066] In some examples, the application store 112 may store one or more applications for execution by one or more processors in at least one of the optional console 110, the near-eye display device 120, the input / output interface 140, and / or the optional external imaging device 150. An application may include a group of instructions that, when executed by a processor, generates content for presentation to the user. Examples of the applications may include gaming applications, conferencing applications, video playback application, or other suitable applications.

[0067] In some examples, the virtual reality engine 116 may execute applications within the artificial reality system environment 100 and receive position / acceleration / velocity information of the near-eye display device 120, predicted future positions of the near-eye display device 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 1 18. Based on the received information, the virtual reality engine 116 may determine content including, e.g., virtual reality images, to provide to the near-eye display device 120 for presentation to the user.

[0068] In some examples, the eye tracking module 118, which may be implemented as a processor, may receive eye tracking data from the eye tracking unit 130 and determine the position of the user’s eye based on the eye tracking data. In some examples, the position of the eye may include an eye’s orientation, location, or both relative to the near-eye display device 120 or any element thereof. Accordingly, in these examples, because the eye’s axes of rotation change as a function of the eye’s location in its socket, determining the eye’s location in its socket may allow the eye tracking module 118 to more accurately determine the eye’s orientation.

[0069] Generally speaking, any one or more of the components and / or functionalities described in reference to any of the Figures herein may be implemented by hardware, software, and / or any combination thereof, according to examples of the present disclosure. In some examples, the components and / or functionalities may be implemented 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 hardware and data processing components used to implement the various processes, operations, logic, and circuitry described in connection with the examples described herein may be implemented with a general purpose single- and / or multi-chip 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 / storage may include 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 some examples, thememory / storage 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.

[0070] Figures 2A and 2B illustrate a front prospective view and a back prospective view, respectively, of a near-eye display device in the form of a head-mounted display (HMD) device 200 which may be implemented with an inward-facing and / or an outward-facing projection system to which examples of the present disclosure may be applied. In some examples, the head-mounted display (HMD) device 200 may be a specific implementation of the near-eye display 120 of Figure 1 , and may be configured to operate as a virtual reality (VR) system, an augmented reality (AR) system, a mixed reality (MR) system, and / or as part of any such system that uses displays or wearables, or any combination thereof. In some examples, the head-mounted display (HMD) device 200 may include a display 210, a body 220 and a head strap 230. In some examples, the head-mounted display (HMD) device 200 may include additional, fewer, and / or different components than shown and / or described in reference to Figures 2A-2B.

[0071] Figure 2A is a frontal prospective view 200A showing a front side 225, a bottom side 223, and a right side 229 of the body 220, as well as the display 210 and the head strap 230 of the head-mounted display (HMD) device 200. Figure 2B is a bottom rear prospective view 200B showing the bottom side 223, the front side 225, and a left side 227 of the body 220, as well as the display 210 and the head strap 230 of the head-mounted display (HMD) device 200. 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 head-mounted display (HMD) device 200 for allowing a user to mount the head-mounted display (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.

[0072] In some examples, the head-mounted display (HMD) device 200 (including, e.g., the display 210) in Figures 2A-2B may include any number of processors, display electronics, and / or display optics similar to the one or more processors 121 , the display electronics 122, and the display optics 124 described in reference to Figure 1. In some examples, the display electronics and display optics of the head-mounted display (HMD) device 200 may display and / or facilitate the display of media or other digital content including virtual and / or augmented views of a physical, real-world environment with computergenerated elements. Examples of the media or digital content presented by the head-mounted display (HMD) device 200 may include images (e.g., two-dimensional (2D) or three- dimensional (3D) images), videos (e.g., 2D or 3D videos), audio, or any combination thereof.In some examples, the display electronics may display a three-dimensional (3D) image, e.g., using stereoscopic effects produced by two-dimensional panels, to create a subjective perception of image depth. In some examples, the display optics in the head-mounted display (HMD) device 200 may include a single optical element or any number of combinations of various optical elements, such as waveguides, gratings, optical lenses, optical couplers, mirrors, etc., as well as mechanical couplings to maintain relative spacing and orientation of the optical elements in the combination, such as are described above in reference to the display optics 124 in Figure 1.

[0073] In some examples, the head-mounted display (HMD) device 200 in Figures 2A- 2B may include one or more inward / outward projectors, similar to the one or more inward projectors 173 and / or one or more outward projectors 172 of Figure 1. In some examples, the one or more inward projectors of the head-mounted display (HMD) device 200 may project an image for direct observation by the user’s eye and / or project a fringe or other pattern on the eye. In some examples, the one or more outward projectors of the head-mounted display (HMD) device 200 may project a fringe or other pattern on the external environment and / or objects / surfaces within the external environment in order to, for example, perform 3- dimensional (3D) mapping of the external environment. In some examples, the one or more inward / outward projectors of the head-mounted display (HMD) device 200 may include one or more of a liquid crystal display (LCD) and / or a light-emitting diode (LED); more specifically, the one or more inward / outward projectors of the head-mounted display (HMD) device 200 may include, e.g., one or more of a liquid crystal display (LCD), a light emitting diode (LED) or micro-light emitting diode (mLED), an organic light emitting diode (OLED), an inorganic light emitting diode (ILED), an active-matrix organic light emitting diode (AMOLED), a transparent organic light emitting diode (TLED), any other suitable light source, and / or any combination thereof. It should be appreciated that in some examples, the inward projectors of the headmounted display (HMD) device 200 may be placed near and / or closer to a user’s eye (e.g., “eye-side”). It should be appreciated that, in some instances, utilizing a back-mounted inward projector 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.

[0074] In some examples, the head-mounted display (HMD) device 200 may also include an eye tracking system, one or more locators, one or more position sensors, and an inertial measurement unit (IMU), similar to the eye tracking unit 130, the one or more locators 126, the one or more position sensors 128, and the inertial measurement unit (IMU) 132, respectively, described in reference to Figure 1 . In some examples, the head-mounted display (HMD) device 100 may include various other sensors, such as depth sensors, motion sensors, image sensors, light sensors, and / or the like. Some of these sensors may sense any number of structured or unstructured light patterns projected by the one or more inward / outwardprojectors of the head-mounted display (HMD) device 200 for any number of purposes, including, e.g., sensing, eye tracking, and / or the creation of virtual reality (VR) content.

[0075] In some examples, the head-mounted display (HMD) device 200 may include and / or be operably connected to a virtual reality engine (not shown), similarto the virtual reality engine 1 16 described in reference to Figure 1 , that may execute applications within the headmounted display (HMD) device 200 and receive depth information, position information, acceleration information, velocity information, predicted future positions, or any combination thereof of the head-mounted display (HMD) device 200 from the various sensors. In some examples, the information received by the virtual reality engine may be used for producing a signal (e.g., display instructions) to the one or more display assemblies. In some examples, the head-mounted display (HMD) device 200 may include locators (not shown), similar to the one or more locators 126 described in reference to Figure 1 , which may be located in fixed positions on the body 220 of the head-mounted display (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.

[0076] As stated above, the head-mounted display (HMD) device 200 may include additional, fewer, and / or different components than shown and / or described in reference to Figures 2A-2B. In some examples, the head-mounted display (HMD) device 200 may include an input / output interface (similar to the input / output interface 140 in Figure 1), a console (similar to the console 110 described in reference to Figure 1), and / or a camera to capture images or videos of the user’s environment to present the user with, e.g., augmented reality (AR)Zvirtual reality (VR) content. In some examples, the head-mounted display (HMD) device 200 may include one or more cameras to capture reflections of patterns projected by the one or more inward / outward projectors.

[0077] Figures 3A and 3B illustrate a perspective view 300A and a top view 300B, respectively, of a near-eye display device 300 in the form of a pair of glasses having both an inward-facing and an outward-facing projection systems to which examples of the present disclosure may be applied. In some examples, the near-eye display device 300 may be a specific implementation of the near-eye display device 120 of Figure 1 , and may be configured to operate as a virtual reality (VR) system, an augmented reality (AR) system, a mixed reality (MR) system, and / or as part of any such system that uses displays or wearables, or any combination thereof. As shown in Figures 3A-3B, the near-eye display device 300 may include a frame 305, one or more outward pattern projectors 310, one or more eye tracking projectors 315 (which effectively operate as inward pattern projectors), an outward-facing camera(s) 320, an eye tracking camera(s) 325, and a display 390.

[0078] As shown in Figures 3A-3B, the near-eye display device 300 may include an inward-facing imaging / projection system, comprising the one or more eye tracking projectors 315 (i.e., inward pattern projectors) and the eye tracking camera(s) 325, and an outwardfacing imaging / projection system, comprising the one or more outward pattern projectors 310 and the outward-facing camera(s) 320. In some examples, the inward-facing imaging / projection system of the near-eye display device 300 may be an eye tracking system, where the one or more eye tracking projectors 315 project a pattern directly on the user’s eye(s) and the eye tracking camera(s) 325 captures one or more reflections of the projected pattern on the user’s eye(s), and the eye tracking system uses the captured reflections to track the user’s eye(s). In some examples, the eye tracking camera(s) 225 may be a single photon avalanche diode (SPAD) sensor. In some examples, the one or more eye tracking projectors 315 may project a pattern such as, for example, a structured image (e.g., a fringe pattern) projected onto the eye by a micro-electromechanical system (MEMS) based scanner reflecting light from a light source (e.g., a laser).

[0079] As shown in FIG. 3B, in some examples, the outward-facing imaging / projection system of the near-eye display device 300 may include the one or more outward pattern projectors 310, which project a pattern directly on an external environment 350 and / or one or more objects / surfaces in the external environment 350, and the outward-facing camera(s) 320, which captures one or more reflections of the projected pattern on the one or more objects / surfaces or all or part of the entire external environment 350. In some examples, such an outward-facing imaging / projection system may serve a variety of purposes, including, but not limited to, profilometry, determining surface patterns / structures of objects in the external environment 350, determining distances from the user to one or more objects / surfaces in the external environment 350, determining relative positions of one or more objects / surfaces to each other in the external environment 350, determining relative velocities of one or more objects / surfaces in the external environment 350, etc., as would be understood by one of ordinary skill in the art. In some examples, the outward-facing imaging / projection system of the near-eye display device 300 may also be employed to capture images of the external environment 350. In such examples, the captured images may be processed, for example, by a virtual reality engine to add virtual objects to the captured images or modify physical objects in the captured images, and the processed images may be displayed to the user by the display 390 for augmented reality (AR) and / or mixed reality (MR) applications.

[0080] In some examples, the display 390 may include, in whole or in part, one or more processors, display electronics, and / or display optics similar to the one or more processors 121 , the display electronics 122, and the display optics 124 in Figure 1 , and may be configured to present media or other content to a user, including, e.g., virtual reality (VR), augmented reality (AR) system, and / or mixed reality (MR) content. In some examples, thedisplay 390 may include any number of light sources, such as, e.g., 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), etc., and any number of optical components, such as waveguides, gratings, lenses, mirrors, etc., as would be understood by one of ordinary skill in the art.

[0081] As shown in FIG. 3B, in some examples, the display 390 of the near-eye display device 300 may include optics 391 and a waveguide 393, which may be coupled to a projector (such as, e.g., the one or more inward projectors 173 of Figure 1). In some examples, the display 390 may combine the view of the external environment 350 and artificial reality content (e.g., computer-generated images). In some examples, light from the external environment 350 may traverse a “see-through” region of the waveguide 393 in the display 390 to reach a user’s eye 355 (located somewhere within an eye box), while images are also projected for the user to see as part of an augmented reality (AR) display and / or a mixed reality (MR) display.

[0082] In such examples, the light of images projected by the projector may be coupled into a transparent substrate of the waveguide 393, propagate within the waveguide 393, be coupled with light from the user’s actual environment, and be directed out of the waveguide 393 at one or more locations towards a user’s eye 355 located within the eye box. In such examples, the waveguide 393 may be geometric, reflective, refractive, polarized, diffractive, and / or holographic, as would be understood of one of ordinary skill in the art, and may use any one or more of macro-optics, micro-optics, and / or nano optics (such as, e.g., metalenses and / or metasurfaces). In some examples, the optics 391 of the display 390 may include optical polymers, plastic, glass, transparent wafers (e.g., Silicon Carbide (SiC) wafers), amorphous silicon, Silicon Oxide (SiO2), Silicon Nitride (SiN), Titanium Oxide (TiO), optical nylon, carbonpolymers, and / or any other transparent materials used for such a purpose, as would be understood by one of ordinary skill in the art.

[0083] In some examples, the near-eye display device 300 may further include various sensors on or within a frame 305, such as, e.g., any number of depth sensors, motion sensors, position sensors, inertial sensors, and / or ambient light sensors. 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 (which may or may not include the outward-facing camera(s) 320). In some examples, the various sensors may be used as input devices to control or influence the displayed content of the near-eye display device 300, and / orto provide an interactive virtual reality (VR), augmented reality (AR), and / or mixed reality (MR) experience to a user of the near-eye display device 300. In some examples, the various sensors may also be used for stereoscopic imaging or other similar application.

[0084] In some examples, the near-eye display device 300 may further include one or more illuminators to project light into a physical environment (which may or may not include, e.g., the outward pattern projector(s) 310). The projected light may be associated with different frequency bands (e.g., visible light, infra-red light, ultra-violet light, etc.), and may serve various purposes. In some examples, the one or more illuminators may be used as locators, such as the one or more locators 126 described above with respect to Figure 1 . In such examples, the near-eye display device 300 may also include an image capture unit (which may or may not include the outward-facing camera(s) 320 and / or the external imaging device 150 of Figure 1), which may capture images of the physical environment in the field of view. In some instances, the captured images may be processed, for example, by a virtual reality engine (such as, e.g., the virtual reality engine 1 16 of Figure 1) to add virtual objects to the captured images or modify physical objects in the captured images, and the processed images may be displayed to the user by the display 390 for augmented reality (AR) and / or mixed reality (MR) applications.

[0085] In some examples, a majority of electronic components of the near-eye display device 300 in the form of a pair of glasses may be included in the frame 305 of the glasses (e.g., a top bar, a bridge, a rim, a lens, etc.). Examples of such electronic components included in the frame 305 include, but are not limited to, a camera, a sensor, a projector, a speaker, a battery, a microphone, and a battery management unit (BMU). In some examples, a battery management unit (BMU) may be an electronic system that may be used to manage charging and discharging of a battery (e.g., a lead acid battery). In some examples, the battery management unit (BMU) may, among other things, monitor a state of the battery, determine and report data associated with the battery, and provide environmental control(s) for the battery. In some examples, the temples 306 may be provided with a tapering profile, based on design considerations for the specific implementation. In such examples, the tapered temples may be utilized to house various electronic components. For example, in some cases, a microphone or speaker may often be placed towards a rear of a temple arm, near a user’s ear, and as such, in many cases, a battery may be more likely to be placed near a front of the temple arm.

[0086] In Figure 3B, an eye tracking system (such as that described in reference to eye tracking unit 130, the eye tracking module 1 18, and the inward projector(s) 173 of Figure 1) may be implemented by the eye tracking projector(s) 315, which project patterns and / or other suitable lighting for performing eye tracking upon the user’s eye 355, the eye tracking camera(s) 325, which receive reflections of the light of the eye tracking projector(s) 315 from the user’s eye 355, and a controller (or controllers) 317, which process the reflections received by the eye tracking camera(s) 325 to perform eye tracking. In some examples, the controller 317 may be similar to the one or more processor(s) 121 in Figure 1 (and thus may perform awide variety of functions for the near-eye display device 300), other processor(s) which perform several tasks, and / or a processor(s) dedicated to performing eye tracking.

[0087] In some examples, the controller 317 for performing eye tracking may be communicatively connected with a memory, which may be at least one non-transitory computer-readable storage medium storing instructions executable by the controller 317. The controller 317 may include multiple processing units, and those multiple processing units may further execute instructions in parallel. The at least one 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 various examples, the controller 317 may be further subdivided into multiple devices (for example, the functions of the controller 317 may be separated among various components, such as a digital signal processing (DSP) chip for eye tracking analysis as well as a Central Processing Unit (CPU) for controlling, e.g., the eye tracking projector(s) 315).

[0088] As mentioned above, it may be beneficial for the various components in any near-eye display device 100, such as the head-mounted display (HMD) device 200 in Figures 2A-2B and the near-eye display device 300 in the form of a pair of glasses in Figures 3A-3B, to have a relatively small size and negligible weight for portability and user comfort. Accordingly, it may be desirable to reduce the size, location, power / energy, and other requirements of the eye tracking system in any near-eye display device to increase its overall efficiency. Similarly, it may be desirable to increase the accuracy, speed, and other requirements of the eye tracking system in any near-eye display device.

[0089] According to examples of the present disclosure, an integrated circuit or chip may include (i) a Vertical-Cavity Surface Emitting Laser (VCSEL) acting as an illumination source for camera-based or imaged-based eye tracking; and (ii) a Self-Mixing Interferometer (SMI) acting as both an illumination source and an image sensor for eye tracking. As used herein, the terms “integrated circuit,” “chip,” or “microchip” may be used interchangeably and are intended to have their broadest possible meaning in referring to one or more electronic circuits on a small flat piece of semiconductor material, which may be manufactured using lithographic techniques, such as, e.g., photolithography. In some examples, a single chip may include more than one Vertical-Cavity Surface Emitting Laser (VCSEL) and / or more than one Self-Mixing Interferometer (SMI). As used herein, the terms “combined chip,” “combined ... chip,” “combo chip,” or “combo ... chip” may be used interchangeably and are intended to have their broadest possible meaning in referring to a chip having one or more Vertical-Cavity Surface Emitting Lasers (VCSELs) and / or one or more Self-Mixing Interferometers (SMIs) in accordance with the present disclosure, as would be understood by one of ordinary skill in the art.

[0090] In some examples, a chip combining the Vertical-Cavity Surface Emitting Laser(VCSEL) acting as an illumination source for camera-based eye tracking and the Self-Mixing Interferometer (SMI) acting as both an illumination source and an image sensor for eye tracking may be manufactured using a single fabrication method, technique, and / or process. In some examples, the Self-Mixing Interferometer (SMI) may be manufactured in roughly the form of a Vertical-Cavity Surface Emitting Laser (VCSEL). In some examples, lithography may be used in the fabrication process, including, for example, such techniques as photolithography, scanning lithography, soft lithography, nanoimprint lithography, magnetolithography, nanofountain drawing, nanosphere lithography, neural particle lithography, plasmonic lithography, stencil lithography, and / or any other past, present, or future lithographic technique suitable for fabricating a chip in accordance with the present disclosure, as would be understood by one of ordinary skill in the art.

[0091] According to examples of the present disclosure, the Vertical-Cavity Surface Emitting Laser (VCSEL) on the combined chip acting as an illumination source for camerabased eye tracking (which hereinafter may be referred to, inter alia, as “the VCSEL pattern projector”) may project a pattern on the user’s eye while the Self-Mixing Interferometer (SMI) acting as both an illumination source and an image sensor for eye tracking (which hereinafter may be referred to, inter alia, as “the SMI eye tracking sensor”) may both project a beam of light on the user’s eye, receive the reflection of that light from the user’s eye, modulate the received beam (by self mixing both the received beam and the output beam), and produce an electrical signal corresponding to received, modulated beam.

[0092] In some examples, the VCSEL eye tracking pattern projector may be suitably modified to emulate an LED emission pattern by projecting a wide emission beam which may be used to illuminate a user’s eye for camera-based eye tracking. Suitable modifications in accordance with various examples of the present disclosure include, but are not limited to: modifying the size or shape of the emitting aperture of the VCSEL eye tracking pattern projector; modifying the size or shape of the laser cavity of the VCSEL eye tracking pattern projector; modifying one or more of the reflector layers of the VCSEL eye tracking pattern projector; disposing a metasurface on top of the VCSEL eye tracking pattern projector; and / or disposing another type of suitable surface (such as, e.g., a meta lens, a suitable grating, etc.) on top of the VCSEL eye tracking pattern projector. In some examples, the top reflector layer of the VCSEL eye tracking pattern projector may be cut through during the fabrication process to provide a hole, whereby the VCSEL eye tracking pattern projector, when activated, may provide a wide beam emission similar to an LED.

[0093] Because, in examples according to the present disclosure, the VCSEL eye tracking pattern projector may be suitably modified to project a wide emission beam, thereby appearing more like a light beam projected by an LED than the relatively focused / tight light beam typically projected by lasers like a VCSEL, the term “quasi-LED” may be used hereinwhen referring to the VCSEL eye tracking pattern projector to indicate this difference in light projected therefrom, and does not in any way indicate a technical and / or electrical / electronic similarity with an LED.

[0094] The terms “VCSEL pattern projector,” “VCSEL eye tracking pattern projector,” “VCSEL eye tracking quasi-LED pattern projector,” “VCSEL eye tracking quasi-LED projector,” “VCSEL quasi-LED projector,” “quasi-LED VCSEL,” “VCSEL quasi-LED” and similar phrases may be used interchangeably to refer to the part of the combined chip acting substantially as a projector in accordance with examples of the present disclosure as distinguished from the part of the combined chip acting substantially as a sensor. Similarly, the terms “SMI eye tracking sensor,” “SMI sensor,” and similar phrases using “SMI” may be used interchangeably to refer to the part of the combined chip acting substantially as a sensor in accordance with examples of the present disclosure as distinguished from the part of the combined chip acting substantially as a projector. This usage, of course, does not exclude from the present disclosure examples where the two separate parts of the combined chip act in varying degrees as both projector and sensor, as indeed the Self-Mixing Interferometer (SMI) eye tracking sensor acts substantially as both a projector and a sensor.

[0095] According to examples of the present disclosure, eye tracking using the SMI for non-image sensing may be typically more accurate, faster, and more power efficient than camera-based eye tracking (i.e., image-based eye tracking) when detecting changes in the angular velocity of the user’s eye. In some examples, SMI-based non-image eye tracking may be able to accurately track / fix eye movement (i.e., angular velocity) to a range of about % degree to about a ! degree per second within less than 100 microseconds. In some examples, the non-image-based eye tracking provided by one or more SMI eye tracking sensors (e.g., rotational movement) may be combined or otherwise integrated with imagebased and / or camera-based eye tracking (e.g., gaze vector sensor or gaze position sensing) with a slower tracking / fixing / determining rate to obtain complete gaze tracking at a higher accuracy and speed.

[0096] As indicated above, in some examples, combining and / or otherwise integrating (i) the non-image-based eye tracking provided by the SMI eye tracking sensor and (ii) the image-based eye tracking which illumination may be, at least in part, provided by the VCSEL) eye tracking pattern projector, may provide more accurate eye tracking than either type of eye tracking alone. Accordingly, such examples of one or more combined chips providing integrated non-image and image sensing eye tracking may also be faster and more power efficient than systems achieving the same level of accuracy using other means, techniques, and / or methods.

[0097] Figure 4 is a simplified block diagram of a cross-sectional view of a combined SMI eye tracking sensor and quasi-LED VCSEL for eye tracking projector. The combined SMIeye tracking sensor and quasi-LED VCSEL pattern projector chip 400 (which hereinafter may be referred to as the “combined SMI / VCSEL chip 400,” “combined SMI / quasi-LED VCSEL chip 400,” “combined SMI / VCSEL quasi-LED chip 400,” “combined SMI / VCSEL quasi-LED projector chip 400,” “combined SMI / VCSEL quasi-LED pattern projector chip 400,” “combined SMI / VCSEL pattern quasi-LED projector chip 400,” “combined SMI sensor / VCSEL chip 400,” “combined SMI sensor / quasi-LED VCSEL chip 400,” “combined SMI sensor / VCSEL quasi- LED chip 400,” “combined SMI sensor / VCSEL quasi-LED projector chip 400,” and similar phrases obvious by context) shown in Figure 4 is provided to illustrate the explanation below of this example, and omits aspects, features, and / or components not germane to examples of the present disclosure, as would be understood by one of ordinary skill in the art; moreover, the components shown in Figure 4 may not be shown in accurate aspect and / or ratio of relative sizes. For instance, the optical cavities 415 and 455 may in some examples be only a small fraction of the total size of the combined SMI / quasi-LED VCSEL chip 400 and thus the optical cavities 415 and 455 may in no way approximate the widths of the reflectors 413, 417, 453, and 457 as they do in Figure 4. As explained, the sizes, proportions, relative aspects, etc., of the elements shown in Figure 4 are not intended to be accurate, as would be understood by one of ordinary skill in the art, but rather to illustrate examples of the present disclosure.

[0098] The combined SMI sensor / VCSEL quasi-LED projector chip 400 shown in Figure 4 may be disposed in many different locations of a near-eye display device, such as, e.g., in the frame on the periphery of one of the lenses of the near-eye display device (similarly to the eye tracking projector(s) 315 of Figure 3B) and / or embedded in the lens itself (similarly to the array 610 in the lens of the near-eye display device 600 in Figure 6 discussed further below).

[0099] In some examples, one or more signal amplifiers may be included on the combined SMI eye tracking sensor and VCSEL eye tracking quasi-LED pattern projector chip 400; in other examples, one or more signal amplifiers may be electrically connected to, but located externally from, the combined SMI eye tracking sensor and VCSEL eye tracking pattern quasi-LED projector chip 400. In some examples, other light sources including, for example, pattern projecting light emitting diodes (LEDs), may also be used for eye tracking purposes by the near-eye display device and may be disposed on the frame of the near-eye display device.

[0100] As would be understood by one of ordinary skill in the art, the directional terms “top” and “bottom” are used herein for the sake of convenience and ease of explanation, and are not intended to necessarily have any separate directional meaning regarding the construction of optical lens assemblies according to examples of the present disclosure. As used herein, “bottom” may refer to the portion of the optical lens assembly closest to the light source, where the light may enter the optical lens assembly, while the “top” may refer to theportion of the optical lens assembly furthest from the light source, where the light may exit / project from the optical lens assembly.

[0101] In Figure 4, the combined SMI sensor / VCSEL quasi-LED projector chip 400 may include a SMI eye tracking sensor 410 (hereinafter, “SMI sensor 410”) and a VCSEL eye tracking quasi-LED pattern projector 450 (hereinafter, “VCSEL quasi-LED projector 450”) on / in a substrate 405. In some examples, the substrate 405 may include one or more dielectric materials and one or more semiconductor materials, such as, e.g., Gallium Arsenide (GaAs), Aluminum Arsenide (AlAs), any of the various types of silicon (e.g., Silicon Dioxide (SiO2), Silicon Nitride (SiN), etc.), Titanium Oxide (TiO), etc., as would be understood by one of ordinary skill in the art.

[0102] As shown in Figure 4, a portion 459 above the VCSEL quasi-LED projector 450 may be etched away from the top of the combined SMI / quasi-LED VCSEL chip 400. Accordingly, as described below in relation to Figure 9, in some examples, all of the layers of the combined SMI / quasi-LED VCSEL chip 400 may be fabricated initially, and then, in the portion intended to be the VCSEL quasi-LED projector 450, the appropriate portions of the top layers may be etched away. In some examples, the VCSEL quasi-LED projector 450 may project a wide emission beam similar to a light pattern emitted by an LED in an eye tracking system of a near-eye display device.

[0103] The combined SMI / quasi-LED VCSEL chip 400 may be communicatively connected to a controller 430, which may, in turn, include a processor 433 and a memory 435. The controller 430 may be, in part or whole, any one of the controller(s) 317 in Figure 3B, the processor 121 in Figure 1 , and / or another processor in, on, or nearthe combined SMI / VCSEL quasi-LED projector chip 400. The combined SMI / quasi-LED VCSEL chip 400 may be one in an array of similar chips in a near-eye display device (such as those shown and described in reference to Figure 6), and the controller 430 may control one, several, and / or all of the chips in the array, as well as other components in the eye tracking system of a near-eye display device.

[0104] In some examples, both the SMI sensor 410 and the VCSEL quasi-LED projector 450 may have VCSEL constructions, architectures, and / or fabrications. In such VCSEL examples, the VCSEL may include, for example, a VCSEL with multiple active regions (e.g., a bipolar cascade VCSEL); a tunnel junction VCSEL; a tunable VCSEL which may employ, e.g., a micro-electromechanical system (MEMS); a wafer-bonded and / or wafer-fused VCSEL; a Vertical External Cavity Surface Emitting Laser (VECSEL); a Vertical Cavity Semiconductor Optical Amplifier (VCSOA) which may be optimized as amplifiers as opposed to oscillators; two or more Vertical Cavity Surface Emitting Lasers (VCSELs) disposed on top of one another (i.e., vertically) such that each one pumps the one on top of it (e.g., monolithically optically pumped VCSELs); any other suitable VCSEL construction,architecture, and / or fabrication, as would be understood by one of ordinary skill in the art in light of the examples of the present disclosure; and / or other constructions, architectures, and / or fabrications suitable for the present disclosure may be employed besides a VCSEL, such as — with appropriate architectural modifications, for example, an Edge-Emitting Laser (EEL), a Horizontal Cavity Surface Emitting Laser (HC-SEL), a Quantum Dot Laser (QDL), a Quantum Cascade Laser (QCL), a micro-Light Emitting Diode (mLED), any other form of solid state laser, and / or any light source suitable for examples according to the present disclosure, as would also be understood by one of ordinary skill in the art.

[0105] In some examples, the total thickness of combined SMI / quasi-LED VCSEL chip 400 may be less than 125 microns, and may be in the range of about 85 microns to about 1 15 microns. In other examples, the total thickness may range from roughly 50 microns to over 300 microns, depending on the specific implementation of the example according to the present disclosure. In some examples, the total width and / or breadth of the combined SMI / quasi-LED VCSEL chip 400 may be less than roughly 50 microns and / or may be more than over 300 microns, depending on the specific implementation of the example according to the present disclosure. In some examples, the total width / breadth may be in the range of roughly 75 microns to roughly 125 microns which may thereby facilitate its lack of visibility to the user when, for example, embedded in the lens of a near-eye display device, an example of which is described in relation to Figure 6 below.

[0106] Generally speaking, the combined SMI / quasi-LED VCSEL chip 400 may include a top reflector layer, a middle reflector layer, and a bottom reflector layer, where the top and middle reflector layers enclose an active region / optical cavity, and the middle and bottom layers enclose a photodetector (PD)Zactive region layer. Both the SMI sensor 410 and the VCSEL quasi-LED projector 450 include the active region / optical cavity between the top reflector layer and the middle reflector layer, as this is part of the light generating source. The SMI sensor 410 uses the photodetector (PD)Zactive region layer as part of its functioning, and thus, in some examples, the VCSEL quasi-LED projector 450 may not include a photodetector (PD) / active region layer and the bottom reflector layer, as these are only needed by the SMI sensor 410. In some examples (including Figures 4 and 5), the VCSEL quasi-LED projector 450 may include the photodetector (PD) / active region layer and the bottom reflector layer for the ease and simplicity of fabricating the layers of the combined SMI / quasi-LED VCSEL chip 400. In some examples, the SMI sensor 410 and the VCSEL quasi-LED projector 450 may share one or more layers (such as, e.g., middle reflector layer 413 / 453 in Figure 4).

[0107] The SMI sensor 410 may include a bottom reflector layer 411 , a photodetector (PD) layer 412, a middle reflector layer 413, an optical cavity 415, and a top reflector layer 417, in which an aperture 416 may be formed. The PD Iayer 412 may include, for example, a resonant cavity photodetector (RCVP); whereas, in other examples, other suitable lightdetecting element(s) may be included, as would be understood by one of ordinary skill in the art. In some examples, the top reflector layer 417 may include a p-type distributed Bragg reflector (DBR), and the middle and bottom reflector layers 413 and 411 may include an n- type distributed Bragg reflector (DBR). In some examples, the SMI sensor 410 may be another VCSEL).

[0108] The SMI optical cavity 415 may be employed to generate and project coherent light 420 (indicated by an arrow with a dashed line outline in Figure 4) towards a user’s eye and at least a portion of that projected light may be reflected back to the SMI sensor 410 as reflected light 425 (indicated by an arrow with a dotted line outline in Figure 4). The reflected light 425 interferes with presently generated projected light 420 in the optical cavity 415, and produces a modulated feedback light which is received by the PD layer 412. In some examples, the controller 430 controls the SMI sensor 410 to project the coherent light 420 towards the user’s eye and receives signals / data representing the modulated feedback light from the SMI sensor 410. In some examples, the controller 430 processes this received data / signals to generate position and / or movement information regarding the user’s eye based on, e.g., intensity, power, and / or other measurements / calculations of the modulated feedback light as detected by the PD layer 412.

[0109] The VCSEL quasi-LED projector 450 may include a middle reflector layer 453, an optical cavity 455, and a top reflector layer 457. In some examples, the middle and top reflector layers 453 and 457 may include a distributed Bragg reflector (DBR). In some examples, the VCSEL quasi-LED projector 450 may project an emission pattern 460 (the breadth of which is indicated by the two dotted lines in Figure 4) suitable for performing camera-based eye tracking. In some examples, the emission pattern 460 may be a wide emission beam which emulates the light pattern emitted by an LED suitable for performing camera-based eye tracking. Accordingly, the VCSEL quasi-LED projector 450 may be suitably constructed, manufactured, and / or fabricated such that the emission pattern 460 may be suitable for performing camera-based eye tracking, as described in detail herein.

[0110] The VCSEL quasi-LED projector 450 generates / projects the emission pattern 460 such that one or more eye tracking cameras (such as eye tracking camera(s) 325 in Figures 3A-3B) may receive reflections of the emission pattern 460 and 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 1 18 in Figure 1 or the controller(s) 317 in Figure 3B) may perform eye tracking, as would be understood by one of ordinary skill in the art. In some examples, the emission pattern 460 may include light / radiation in the infrared (IR) spectrum (e.g., about 750nm-1000nm). In some examples, the emission pattern 460 may include light / radiation from any one or more of the ultraviolet spectrum (e.g., about 200-350nm), the visual light spectrum (e.g., about 350nm-750nm), the infrared spectrum, and / or any electromagneticradiation spectrum capable of being employed for eye tracking in accordance with examples of the present disclosure, as would be understood by one of ordinary skill in the art.

[0111] In some examples, to perform eye tracking, the VCSEL quasi-LED projector 450 generates / projects the emission pattern 460 which may form a pattern upon the user’s eye, such as, for example, a statistically random pattern (such as, e.g., a pattern of dots or a pattern of speckles), an interference pattern (such as, e.g., a moire pattern or a fringe pattern), a sinusoidal pattern, a binary pattern, a multi-level pattern (such as, e.g., a multi-level grayscale pattern), a code-based pattern, a color-based pattern, and a geometrical pattern (such as, e.g., a triangular, pyramidal, or trapezoidal pattern). Moreoever, in various examples of the present dislosure, there may be only one projected pattern, or a multitude of patterns, or a series of related patterns, which may be projected either separately, in a series, or simultaneously, as would be understood by one of ordinary skill in the art. In some examples, periodic patterns (such as, e.g., fringe patterns) and / or non-periodic patterns (such as, e.g., speckle patterns) may be used. In some examples, the controller 430 may control the VCSEL quasi-LED projector 450 to project the emission pattern 460. In some examples, the VCSEL quasi-LED projector 450 may be controlled by 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 1 18 in Figure 1 or the controller(s) 317 in Figure 3B) to project the emission pattern 460.

[0112] In Figure 4, the controller 430 may be implemented as the processor 433 and the memory 435. In some examples, the controller 430 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 430 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 433 may be implemented with a general purpose single- and / or multi-chip processor, a single- and / or multicore 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 435 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 435 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.

[0113] In some examples, the combined SMI / quasi-LED VCSEL chip 400 may be integrated into and / or employed as a component in other systems and / or for other functionalities of a near-eye display device. For instance, the combined SMI / quasi-LED VCSEL chip 400 may include, in some examples, additional components, such as, for example, all or part of the inertial measurement unit (IMU) 132 in Figure 1 , the position sensor(s) 128 in Figure 1 , other inertia / accelerometer-based sensors, and / or any other sensors, as would be understood by one of ordinary skill in the art. In examples integrating all or part of one or more inertia / accelerometer-based sensors, data / signals received from the one or more inertia / accelerometer-based sensors may be used to perform denoising and motion artifact removal. Similarly, in some examples, the controller 430 may be, in whole or part, integrated into and / or employed as a processing component the inertial measurement unit (IMU) 132 in Figure 1 , the position sensor(s) 128 in Figure 1 , other inertia / accelerometer- based sensors, any other sensors, and / or any other systems and / or functionalities of the near- eye display device, as would be understood by one of ordinary skill in the art.

[0114] Figure 5 is a simplified block diagram of a cross-sectional view of a combined SMI eye tracking sensor and VCSEL eye tracking pattern projector on a chip, according to an example. In Figure 5, the combined SMI eye tracking sensor and VCSEL eye tracking quasiLED pattern projector chip 500 (which hereinafter may be referred to as the “combined SMI / VCSEL chip 500,” “combined SMI / quasi-LED VCSEL chip 500,” “combined SMI / VCSEL quasi-LED projector chip 500,” and similar phrases obvious by context and also used in reference to the combined SMI sensor / quasi-LED VCSEL chip 400) may include a SMI eye tracking sensor 510 (hereinafter, “SMI sensor 510”) and a VCSEL eye tracking pattern quasi- LED projector 550 (hereinafter, “VCSEL quasi-LED projector 550”) on / in a substrate. The combined SMI / quasi-LED VCSEL chip 500 shown in Figure 5 is provided to illustrate the explanation below of this example, and omits aspects, features, and / or components not germane to examples of the present disclosure, as would be understood by one of ordinary skill in the art; moreover, the components shown in Figure 5 may not be shown in accurate aspect and / or ratio of relative sizes.

[0115] As shown in Figure 5, and similarly to the combined SMI / quasi-LED VCSEL chip 400 in Figure 4, the combined SMI / quasi-LED VCSEL chip 500 may include a top reflector layer, a middle reflector layer, a bottom reflector layer, an active region / optical cavity between the top and middle reflector layers, and a photodetector (PD)Zactive region layer between the middle and bottom layers. In Figure 5, the top reflector layer is a p-type distributed Braggreflector (p-DBR) layer, and the middle and bottom reflector layers are n-type distributed Bragg reflector (n-DBR) layers.

[0116] As shown in Figure 5, all the layers of the combined SMI / quasi-LED VCSEL chip 500 may be fabricated in substantially the same process, with many of the fabricated layers also being substantially the same. In some examples, both the SMI sensor 510 and the VCSEL quasi-LED projector 550 may be based on the same general VCSEL structure; however, the VCSEL quasi-LED projector 550 in some examples may go through additional fabrication sequences (some of which are discussed below). In some examples, the sizes of the SMI sensor 510 and the VCSEL quasi-LED projector 550 may be different; in some examples, there may be more than one SMI sensor 510 and / or VCSEL quasi-LED projector 550 on the same chip.

[0117] In Figure 5, the n-contacts are shown at the bottom of the layers of the combined SMI / quasi-LED VCSEL chip 500, while the p-contacts are shown at the top. In Figure 5, the p-contacts of the SMI sensor 510 and the VCSEL quasi-LED projector 550 are separated; however, in other examples, the p-contacts may be shared between the SMI sensor 510 and the VCSEL quasi-LED projector 550. In some examples, the SMI sensor 510 and the VCSEL quasi-LED projector 550 may effectively be two separate anodes which share the same cathode (such as, e.g., shown in Figure 7 below).

[0118] As shown in Figure 5, a portion 559 above the VCSEL quasi-LED projector 550 may be etched away from the top of the combined SMI / quasi-LED VCSEL chip 500. During fabrication, the SMI sensor 510 may be protected by a layer of photoresist while the top layer of the VCSEL quasi-LED projector 550 (e.g., the top reflective layer 557) may be etched in order to that VCSEL quasi-LED projector 550 properly emulate a LED by emitting a properly wide emission cone. In some examples, the etching and / or layer removal from the top layer of the VCSEL quasi-LED projector 550 may allow for fine tuning of the emission cone as well as spectral broadening. In some examples, etching methods such as Inductively Coupled Plasma (ICP) etching may be used for wet and / or dry etching. Accordingly, and as described below in relation to Figure 9, in some examples, during the fabrication of the layers of the combined SMI / quasi-LED VCSEL chip 500, additional processes and methods may be performed on the VCSEL quasi-LED projector 550 while the SMI sensor 510 is untouched and / or protected by a coating or other means from the processes and methods being performed on the VCSEL quasi-LED projector 550. These extra processes and methods may be for purposes of beam shaping the emitted light from the VCSEL quasi-LED projector 550. In some examples, the VCSEL quasi-LED projector 550 may project a wide emission beam similar to a light pattern emitted by an LED in an eye tracking system of a near-eye display device.

[0119] In some examples, Figure 5, the SMI sensor 510 and the VCSEL quasi-LEDprojector 550 may share one or more layers, such as, e.g., the middle reflector layer 413 / 453 in Figure 4 and the middle reflector layer 513 / 553 in Figure 5. In some examples, the SMI sensor 510 and the VCSEL quasi-LED projector 550 may share the same PD layer — due to the coherent nature of the detection in the PD layer, the modulated light feedback coupling in the VCSEL quasi-LED projector 550 will not affect its performance.

[0120] In Figure 5, the SMI sensor 510 may include a bottom reflector layer 51 1 , a photodetector (PD) layer 512, a middle reflector layer 513, an optical cavity 515, and a top reflector layer 517, in which an aperture may be formed. The PD layer 512 may include, for example, a resonant cavity photodetector (RCVP); whereas, in other examples, other suitable light detecting element(s) may be included, as would be understood by one of ordinary skill in the art.

[0121] Like the combined SMI / quasi-LED VCSEL chip 400 in Figure 4, the combined SMI / quasi-LED VCSEL chip 500 may be communicatively connected to a controller (not shown), which may, in turn, include a processor and a memory. The controller may be, in part or whole, any one of the controller(s) 317 in Figure 3B, the processor 121 in Figure 1 , and / or another processor in, on, or near the combined SMI / quasi-LED VCSEL chip 500. The combined SMI / quasi-LED VCSEL chip 500 may be one in an array of similar chips in a neareye display device (such as those shown and described in reference to Figure 6), and its controller may control one, several, and / or all of the chips in the array, as well as other components in the eye tracking system of a near-eye display device. In some examples, the controller controls the SMI sensor 510 to project light towards the user’s eye and receives signals / data representing the modulated feedback light from the SMI sensor 510. In some examples, the controller processes this received data / signals to generate position and / or movement information regarding the user’s eye based on, e.g., intensity, power, and / or other measurements / calculations of the modulated feedback light as detected by the PD layer 512.

[0122] In Figure 5, the VCSEL quasi-LED projector 550 may include a bottom reflector layer 551 , a photodetector (PD) layer 552, a middle reflector layer 553, an optical cavity 555, and a top reflector layer 557, in which an aperture may be formed. As discussed above, portions of the top reflector layer 557 may be etched away, such as etched portion 559. In some examples, the VCSEL quasi-LED projector 550 may project an emission pattern suitable for performing camera-based eye tracking, i.e., a wide emission beam which emulates the light pattern emitted by an LED. Accordingly, the VCSEL quasi-LED projector 550 may be suitably constructed, manufactured, and / or fabricated such that the emission pattern may be suitable for performing camera-based eye tracking, as described in detail herein.

[0123] The VCSEL quasi-LED projector 550 generates / projects an emission pattern such that one or more eye tracking cameras (such as eye tracking camera(s) 325 in Figures 3A-3B) may receive reflections, and 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 1 18 in Figure 1 or the controller(s) 317 in Figure 3B) may perform eye tracking, as would be understood by one of ordinary skill in the art. In some examples, the VCSEL quasi-LED projector 550 generates / projects a pattern upon the user’s eye, such as, for example, a statistically random pattern (such as, e.g., a pattern of dots or a pattern of speckles), an interference pattern (such as, e.g., a moire pattern or a fringe pattern), a sinusoidal pattern, a binary pattern, a multi-level pattern (such as, e.g., a multi-level grayscale pattern), a code-based pattern, a color-based pattern, and a geometrical pattern (such as, e.g., a triangular, pyramidal, or trapezoidal pattern). Moreoever, in various examples of the present dislosure, there may be only one projected pattern, or a multitude of patterns, or a series of related patterns, which may be projected either separately, in a series, or simultaneously, as would be understood by one of ordinary skill in the art. In some examples, periodic patterns (such as, e.g., fringe patterns) and / or non-periodic patterns (such as, e.g., speckle patterns) may be used. In some examples, a controller may control the VCSEL quasi-LED projector 550 to project the emission pattern. In some examples, the VCSEL quasi-LED projector 550 may be controlled by 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 1 18 in Figure 1 or the controller(s) 317 in Figure 3B).

[0124] As mentioned above, the VCSEL quasi-LED projector of the combined SMI / quasi-LED VCSEL chip may be suitably constructed, manufactured, and / or fabricated to project an emission pattern suitable for performing camera-based eye tracking. Moreover, Figures 4 and 5 depict specific examples which are non-limiting, and examples according to the present disclosure may be implemented in a wide variety of possible ways in a near-eye display device, as would be understood by one of ordinary skill in the art, some of which are discussed below.

[0125] In some examples, the diameter of the aperture of the VCSEL eye tracking pattern projector may be increased in order to project a larger emission pattern, which may thereby increase the divergence angle of the projected light. In some examples, other components, parts, and / or layers of the VCSEL eye tracking pattern projector may be suitably altered, modified, and / or fabricated to effectively increase the aperture and, in turn, the divergence angle of the light emitted therefrom. For instance, in some examples, the aperture of the optical cavity / active region within the VCSEL eye tracking pattern projector may be suitably altered, modified, and / or fabricated to effectively increase the divergence angle of the light emitted therefrom.

[0126] In some examples, a metasurface may be disposed on the VCSEL eye tracking pattern projector in order to project a larger emission pattern, to thereby increase the divergence angle of the light emitted therefrom. In some examples, the metasurface may be integrated into, part of, and / or replace other layers making up the VCSEL eye tracking patternprojector. In some examples, the metasurface may be integrated into, part of, and / or replace one or more layers making up SMI eye tracking sensor. In some examples, the metasurface may be functioning as a beam shaper and / or have a lensing function. In some examples, the metasurface may be on the order of nanometers and may therefore be thinner than other optical elements and / or layers, while also providing a much higher precision and may be much more resilient than other optical elements. In some examples, the metasurface may be a planar structure which can modulate the local properties (e.g., amplitude, phase, polarization, etc.) of an optical light beam which is transmitted through it. In some examples, the metasurface may comprise a large array of nanostructures, where the shape and dimensions of these nanostructures determine the phase and / or amplitude at which light is scattered from them, thus facilitating substantially complete control over the phase and / or amplitude profile of the light beam which emerges from the metasurface. In such examples, in contrast to conventional optical components which rely on thickness variation to induce a phase profile, the metasurface may realize arbitrary phase distributions using large arrays with subwavelength and ultrathin (tens of nanometers) features. In such examples, the metasurface may be easily realized using a single lithographic step and may be highly suited for patterning a variety of substrates, including nonplanar and soft surfaces. In some examples, the metasurface may include optical polymers, plastic, glass, transparent wafers (e.g., Silicon Carbide (SiC) wafers), amorphous silicon, Silicon Oxide (SiO2), Silicon Nitride (SiN), Titanium Oxide (TiO), optical nylon, carbon-polymers, and / or any other transparent materials used for such a purpose, as would be understood by one of ordinary skill in the art.

[0127] In some examples, the laser cavity of the VCSEL eye tracking pattern projector may be tapered in order to project a larger emission pattern, which may effectively increase the divergence angle of the light emitted therefrom. In other examples, the laser cavity may be otherwise suitably altered, modified, and / or fabricated to effectively increase the divergence angle of the light emitted therefrom. In some examples, the length of the laser cavity may be alterable by one or more electrical and / or mechanical components, such as, for example, a microelectromechanical system (MEMS) suitably stacked in relation to the laser cavity.

[0128] In some examples, a reflector of the VCSEL eye tracking pattern projector may be altered in order to project a larger emission pattern. In some examples, the VCSEL eye tracking pattern projector may include a chirped distributed Bragg reflector (DBR) as a top reflector layer. In some examples, the chirped distributed Bragg reflector (DBR) may be constructed as a short segment of optical fiber that reflects particular wavelengths of light and transmits all others, specifically, an optical fiber where the Bragg grating is “chirped,” i.e., where linear variations are added to what is typically a uniform periodic grating pattern. In such examples, the chirped distributed Bragg reflector (DBR) may have greater dispersion of emitted light than a distributed Bragg reflector (DBR) with a uniform periodic grating pattern.In some examples, other alterations and / or modifications may be implemented in any one or more of the reflector layers of the VCSEL eye tracking pattern projector in order to effectively increase the divergence angle of the light emitted therefrom.

[0129] Figure 6 illustrates a perspective view of a near-eye display device in the form of a pair of glasses having an array of combined SMI eye tracking sensor and VCSEL eye tracking pattern projector chips, according to an example of the present disclosure. In some examples, the near-eye display device 600 may be a specific implementation of the near-eye display device 120 of Figure 1 , the near-eye display device 300 of Figures 3A-3B, or may be employed in a near-eye display device in the form of a head-mounted display (HMD), such as, e.g., the head-mounted display (HMD) device 200 in Figures 2A-2B. The near-eye display device 600 may be configured to operate as a virtual reality (VR) system, an augmented reality (AR) system, a mixed reality (MR) system, and / or as part of any such system that uses displays or wearables, or any combination thereof.

[0130] In Figure 6, a near-eye display device 600 may include a 5x5 array 610 of combined SMI eye tracking sensor and VCSEL eye tracking pattern projector chips (hereinafter, in relation to Figure 6 and depending on the context, referred to individually as “combined chip,” as a group or type as “combined chips,” or as the specific array in Figure 6 as “the chip array 610”). In some examples, the chip array 610 may be connected to a controller(s) 615, which may or may not be disposed in the near-eye display device 600. The near-eye display device 600 shown in Figure 6 is provided to illustrate the explanation below of this example of the chip array 610, and omits aspects, features, and / or components not germane to examples of the present disclosure, as would be understood by one of ordinary skill in the art. For instance, the chip array 610 is only shown in the left lens of the near-eye display device 600 for convenience and brevity of explanation, but may be present in the right lens as well; moreover, any other array sizes, shapes, and configurations are also intended as included as examples of the present disclosure. As another instance, the size and shape of the waveguides 630L and 630R may differ widely according to the implementation of the particular example of the present disclosure.

[0131] As shown in Figure 6, the near-eye display device 600 may include a left inward display projector(s) 620L and a left waveguide 630L in the left lens of the eyeglasses, a right inward display projector(s) 625R and right waveguide 635R in the right lens of the eyeglasses, and an eye tracking camera(s) 640 disposed by the left lens of the eyeglasses (similar eye tracking camera(s) may be disposed on the right lens as well). The left waveguide 610L and right waveguide 615R may be similar in form and function to the waveguide 393 in Figure 3B and / or the display optics 124 in Figure 1. The left inward display projector(s) 620L and right inward display projector(s) 625R may be similar in form and function to the display electronics 122 and / or the inward projector(s) 173 in Figure 1 , and may be employed to project an imageon the user’s eye(s) as part of, for example, a virtual reality (VR) system, an augmented reality (AR) system, a mixed reality (MR) system, and / or as part of any similar such system, as would be understood by one of ordinary skill in the art. In some examples, the combination of the left inward display projector(s) 620L and the left waveguide 630L and the combination of the right inward display projector(s) 625R and the right waveguide 630R may provide the view of both the external environment and computer-generated images to the user’s eyes, in a similar manner as described in relation to the optics 391 and waveguide 391 in Figure 3B. In some examples, the eye tracking camera(s) 640 may perform in a similar manner as described in relation to the eye tracking camera(s) of Figures 3A and 3B, and as generally herein regarding eye tracking systems, such as, for example, described in relation to the eye tracking unit 130, the (optional) eye tracking module 1 18, etc. of Figure 1 and / or the eye tracking camera(s) 325 of Figures 3A and 3B. In some examples, the controller(s) 615 may perform in a similar manner as described in relation to the controller 430 of Figure 4.

[0132] The chip array 610 may include any number of combined chips in accordance with the present disclosure, connected by very small and / or transparent metal traces (e.g., indium tin oxide) in each lens, which may both power and control each of the combined chips in the chip array 610. In some examples, such metal traces may be employed to connect the controller(s) 615 to each of the combined chips in the chip array 610. In some examples, both the chip array 610 and the control / power traces connecting the combined chips may be so small, and positioned so closely to the user’s eye(s), as to be unnoticeable and / or optically insignificant in the user’s vision. In some examples, both the chip array 610 and the control / power traces connecting the combined chips may also be unnoticeable to any other person who is viewing the near-eye display device 600 when worn by the user. In some examples, the total breadth / width of each of the combined chips may be in the range of roughly 75 microns to roughly 125 microns.

[0133] In Figure 6, the SMI eye tracking sensor and the VCSEL eye tracking pattern projector in each of the combined chips in the chip array 640 may be employed in eye tracking. In some examples, the SMI)eye tracking sensor in each of the combined chips in the chip array 640 may be employed in non-image-based eye tracking, where each of the SMI eye tracking sensors projects light onto the user’s eyes, receives light reflected from the user’s eye of the projected light, modulates the received / reflected light (through self mixing interferometry), and generates a feedback signal based on the modulated received / reflected light. In some examples, one, more, and / or all of the feedback signals from the SMI eye tracking sensors are received by the controller(s) 615, which may perform non-image-based eye tracking based on the feedback signals. In some examples, the controller(s) 615 may only perform pre-processing on the feedback signals, and then forward the pre-processed signals to the eye tracking system of the near-eye display device 600; in other examples, thecontroller(s) 615 may be the eye tracking system. In some examples, one, more, and / or all of the SMI eye tracking sensors project light at different wavelengths such that each SMI eye tracking sensor (or sub-group) which transmits at a unique wavelength may effectively isolate its own reflected light from the reflected light at other wavelengths which came from other SMI eye tracking sensors. In some examples, the SMI eye tracking sensors project light in the infrared range, from roughly about 750nm to roughly about 1000nm.

[0134] In some examples, the VCSEL eye tracking pattern projector in each of the combined chips in the chip array 640 may be employed in image-based eye tracking, where each of the VCSEL eye tracking pattern projectors projects light onto the user’s eyes and the eye tracking camera(s) 640 receives light reflected from the user’s eye of the projected light and generates a feedback signal based on the received / reflected light. In some examples, the controller(s) 615 may receive the feedback signals perform image-based eye tracking based on the feedback signals; in other examples, other processors may receive, process, and / or perform the image-based eye tracking based on the feedback signals.

[0135] As referred to above, in some examples, both the SMI eye tracking sensor in each of the combined chips in the chip array 640 may be employed in non-image-based eye tracking and the VCSEL eye tracking pattern projector in each of the combined chips in the chip array 640 may be employed in image-based eye tracking at the same time. In some examples, both the SM) eye tracking sensor and the VCSEL eye tracking pattern projector in each of the combined chips in the chip array 640 may be employed in non-image-based eye tracking at the same time.

[0136] Figure 7 is a planar view of a combined SMI eye tracking sensor and the VCSEL eye tracking pattern projector chip, according to an example of the present disclosure. The combined SMI eye tracking sensor and VCSEL eye tracking pattern quasi-LED projector chip 700 shown in Figure 7 (hereinafter referred to as “the combined SMI / quasi-LED VCSEL eye tracking chip 700’’) is provided to illustrate the explanation below of this example, and omits aspects, features, and / or components not germane to examples of the present disclosure, as would be understood by one of ordinary skill in the art.

[0137] As shown in Figure 7, the combined SMI / quasi-LED VCSEL eye tracking chip 700 may include an SMI eye tracking sensor anode 710 including a light emitting area 715 and a VCSEL eye tracking pattern projector anode 720 including a light emitting area 725. In some examples, the SMI eye tracking sensor anode 710 and the VCSEL eye tracking pattern projector anode 720 share a joint anode 730. In some examples, the combined SMI / quasi- LED VCSEL eye tracking chip 700 may be one in an array of similar chips in a near-eye display device which may be interconnected by a horizontal (row) trace 750 and a vertical (column) trace 760 (such as the chip array 610 and the metal traces described in reference to Figure 6).

[0138] In some examples, the combined SMI / quasi-LED VCSEL eye tracking chip 700 may have an area (indicated by dashed line box 755) connected electrically with the vertical / column trace 750 and an area (indicated by dashed line box 765) connected electrically with the horizontal / row trace 760, where both areas 755 and 765 may be employed for control, read / write, power, and other operations of the combined SMI / quasi-LED VCSEL eye tracking chip 700. In such examples, one or more controllers may transmit control signals to, receive feedback from, etc., the combined SMI / quasi-LED VCSEL eye tracking chip 700 by means of the areas 755 and 765 and their connection to the vertical / column trace 750 and the horizontal / row trace, respectively. In some examples, such one or more controllers may be similar in form, function, construction, disposition, and / or operation to the controller(s) 615 in Figure 6, the controller 430 in Figure 4, the controller(s) 317 in Figure 3B, the eye tracking unit 130, the eye tracking module 118, and / or the processor(s) 121 of Figure 1. In such examples, the one or more controllers may effectively address the combined SMI / quasi-LED VCSEL eye tracking chip 700 by using area 755 as a column ID or x coordinate and the area 765 as a row ID or y coordinate within the array of combined SMI / quasi-LED VCSEL eye tracking chips.

[0139] Figure 8 is a flowchart illustrating a method for eye tracking using a combined SMI eye tracking sensor and VCSEL eye tracking pattern projector chip, according to an example of the present disclosure. The method 800 shown in Figure 8 is provided by way of example and may only be one part of an entire process, procedure, ongoing operation, method, etc., as would be understood by one of ordinary skill in the art. The method 800 may further omit parts of any process, procedure, ongoing operation, method, etc., involved in eye tracking not germane to examples of the present disclosure, as would be understood by one of ordinary skill in the art. Each block shown in Figure 8 may further represent one or more steps, processes, methods, or subroutines, as would be understood by one of ordinary skill in the art. For the sake of convenience and ease of explanation, the blocks in Figure 8 may refer to the components shown in the Figures described herein; however, the method 800 is not limited in any way to the components, apparatuses, and / or constructions described and / or shown in any of the Figures herein.

[0140] As shown in Figure 8, some of the processes indicated by the blocks may overlap and / or may occur substantially simultaneously and, moreover, the blocks may be performed by different processing components. For instance, although each of blocks 810 and 820, blocks 830 and 840, blocks 835 and 845, and / or blocks 850 and 860 may be referred to as being performed “at the same time,” they may be performed substantially continually and thus are all always being performed (although at different stages). As another instance, any of blocks 850, 860, (optional) 865, and / or (optional) 875 may be performed by the same one or more processors / controllers or by different processors / controllers, as discussed in moredetail below. Moreover, as indicated by their dotted-line and dashed-line boxes, blocks 865 and 875 may be optional in some examples. In some examples, the components performing any of blocks 810, 820, 830, 835, 840, and 845 may be controlled / directed to do so by one or more controllers / processors (such as, for example, the controller(s) 615 in Figure 6, the controller 430 in Figure 4, the controller(s) 317 in Figure 3B, the eye tracking unit 130, the eye tracking module 118, and / or the processor(s) 121 of Figure 1 , and / or any other suitable processor / controller, as would be understood by one of ordinary skill in the art).

[0141] At block 810, one or more SMI eye tracking sensors on one or more combined SMI eye tracking sensor and VCSEL eye tracking quasi-LED pattern projector chips (hereinafter, “combined SMI / quasi-LED VCSEL eye tracking chips” or “combined SMI / quasi- LED VCSEL eye tracking chip”) may project / emit a beam of light towards the user’s eye. In some examples, the one or more SMI eye tracking sensors on one or more combined chips may emit one or more beams of light, at one or more wavelengths, towards one or more structures in the user’s eyes (e.g., the iris, sclera, pupil, lens, limbus, eyelid, etc.). In this and the following blocks, the one or more SMI eye tracking sensors on one or more combined chips may be, for example, any one or more of the SMI sensor 410 in Figure 4, the SMI sensor 510 of Figure 5, one of the SMI eye tracking sensors in the chip array 610 of Figure 6, the SMI sensor anode light emitting area 715 in Figure 7, and / or any other SMI eye tracking sensor in accordance with the present disclosure, as would be understood by one of ordinary skill in the art.

[0142] In some examples, the one or more SMI eye tracking sensors on one or more combined chips may project light in block 810 in a time series, where different wavelengths of light are projected at different times, or where different SMI eye tracking sensors (disposed at separate locations) project their light at different times, or any combination thereof. In some examples, one or more of the one or more SMI eye tracking sensors may be able to effectively change any of the phase, wavelength, or other parameter of the light projected in block 810 by adjusting conditions and / or otherwise adaptively modifying the one or more SMI eye tracking sensors.

[0143] At block 820 (which may occur at substantially the same time as block 810 as indicated in Figure 8), one or more quasi-LED VCSEL eye tracking pattern projectors on one or more combined SMI / quasi-LED VCSEL eye tracking chips may project one or more patterns on the user’s eye. In some examples, the one or more quasi-LED VCSEL eye tracking pattern projectors on one or more combined SMI / quasi-LED VCSEL eye tracking chips may generate / project a pattern upon the user’s eye, such as, for example, a statistically random pattern (such as, e.g., a pattern of dots or a pattern of speckles), an interference pattern (such as, e.g., a moire pattern or a fringe pattern), a sinusoidal pattern, a binary pattern, a multi-level pattern (such as, e.g., a multi-level grayscale pattern), a code-based pattern, a color-basedpattern, and a geometrical pattern (such as, e.g., a triangular, pyramidal, or trapezoidal pattern), as would be understood by one of ordinary skill in the art. Moreoever, in various examples of the present dislosure, there may be only one projected pattern, or a multitude of patterns, or a series of related patterns, which may be projected either separately, in a series, or simultaneously, as would be understood by one of ordinary skill in the art. In some examples, periodic patterns (such as, e.g., fringe patterns) and / or non-periodic patterns (such as, e.g., speckle patterns) may be used.

[0144] At block 830, one or more SMI eye tracking sensors on one or more combined chips may receive reflections from the user’s eye of the light emitted in block 810 and modulates the reflected light, thereby generating data / feedback signals. In some examples, the reflected light is received in the resonant cavity of the one or more SMI eye tracking sensors (e.g., optical cavity 415 in Figure 4), where the changed phase of the reflected light is modulated by mixing with the emitted light which has a different phase (i.e., the phase of the light emitted in block 810). This modulated light (e.g., the modulated feedback light of SMI sensor 410 in Figure 4) may be received by a light sensor (such as, e.g., the PD layer 412 of Figure 4) and thereby turned into an electromagnetic signal, which may also be amplified.

[0145] At block 835, the one or more SMI eye tracking sensors on one or more combined chips may transmit the data / feedback signals generated in block 830. In some examples, the one or more SMI)eye tracking sensors transmit the generated data / feedback signals to a dedicated SMI eye tracking processor / controller, a more general eye tracking processor / controller (i.e., capable of non-SMI-based eye tracking), and / or any other suitable processor / controller, as would be understood by one of ordinary skill in the art. In some examples, the generated data / feedback signals may be received and pre-processed by one or more processors / controllers before being received by the eye tracking processor(s) / controller(s).

[0146] At block 840 (which may occur at substantially the same time as block 830 as indicated in Figure 8), one or more eye tracking camera(s) may receive light reflected from the user’s eye of the projected pattern in block 820 and generate image data therefrom. In some examples, the one or more camera(s) may be, e.g., the eye tracking camera(s) 640 of Figure 6, the eye tracking camera(s) 325 of Figures 3A and 3B, one or more light detectors operably connected to the eye tracking module 130 and / or the eye tracking unit 118 in Figure 1 , and / or any other image and / or light detector, as would be understood by one of ordinary skill in the art.

[0147] At block 845 (which may occur at substantially the same time as block 835 as indicated in Figure 8), the one or more eye tracking camera(s) transmit the image data generated in block 840. In some examples, the one or more eye tracking camera(s) transmit the generated image data to a dedicated image-based and / or camera-based eye trackingprocessor / controller, a more general eye tracking processor / controller (i.e., capable of non- image-based and / or non-camera-based eye tracking), and / or any other suitable processor / controller, as would be understood by one of ordinary skill in the art.

[0148] At block 850, the one or more processors / controllers which received the SMI sensor data / feedback signals from block 835 perform non-image-based eye tracking using the received data / feedback signals. In some examples, the one or more processors performing block 850 may include one or more of, e.g., the controller(s) 615 in Figure 6, the controller 430 in Figure 4, the controller(s) 317 in Figure 3B, the eye tracking unit 130, the eye tracking module 1 18, and / or the processor(s) 121 of Figure 1 , and / or any other suitable processor / controller, as would be understood by one of ordinary skill in the art. In some examples, the one or more processors in block 850 may estimate line and / or angular velocity of the user’s eye using Doppler interferometry based on the data / feedback signals. In some examples, the one or more processors in block 850 may estimate a range (or distance) to the user’s eye, a surface quality (e.g., a surface texture) of the user’s eye, a rotational movement of the user’s eye, a position of the user’s eye, and / or a structure of the user’s eye. In some examples, the one or more processors in block 850 may perform Doppler odometry using a Kalman filter and the data / feedback signals, thereby, e.g., determining changes in the eye gaze vector.

[0149] In block 850, the rotational movement of the user’s eye may be retrieved and reconstructed in some examples by phase tracking the Doppler frequencies from multiple positions and / or multiple orientations of the user’s eye (as determined from the SMI sensor data / feedback signals). In some examples, the received data / feedback signals may be used for the ranging of the surface, interface, and volume structures of the user’s eye, which may be used for, e.g., anchor values for tracking the displacement of the eye profile during eye rotation. In some examples, the received data / feedback signals may be employed to generate, e.g., a displacement / velocity map (e.g., a Doppler cloud), a distance map (e.g., a depth cloud), and / or a differential depth cloud. In some examples, the received data / feedback signals may be processed in real-time to match a pre-defined and / or locally defined / calibrated map / library (such as, e.g., a differential depth cloud) and then to extract eye tracking information and / or position information therefrom. In such examples, the locally defined / calibrated map / library may be generated by image-based eye tracking techniques (e.g., camera-based techniques and / or other techniques using the pattern projections of the one or more VCSEL eye tracking pattern projectors on the one or more combined SMI / quasi-LED VCSEL eye tracking chips).

[0150] At block 860 (which may occur at substantially the same time as block 850, or may be integrated with block 850 to be performed by the same entity as indicated by the dashed-line block 865 in Figure 8), one or more processors may perform image-based and / or camera-based eye tracking using the images data received from block 845 (which was basedon reflections of the pattern(s) projected by the one or more VCSEL eye tracking pattern projectors on the one or more combined SMI / quasi-LED VCSEL eye tracking chips). In some examples, the one or more processors performing block 860 may include one or more of, e.g., the controller(s) 615 in Figure 6, the controller 430 in Figure 4, the controller(s) 317 in Figure 3B, the eye tracking unit 130, the eye tracking module 1 18, and / or the processor(s) 121 of Figure 1 , and / or any other suitable processor / controller, as would be understood by one of ordinary skill in the art.

[0151] The dashed-line block 865, as mentioned above, indicates that, in some examples, both blocks 850 and 860 may optionally be performed by the same one or more processors at the same and / or different times. In some examples, the SMI sensor-based eye tracking of block 850 may be performed continually, or repeatedly, multiple times for each time the image-based and / or camera-based eye tracking of block 860 may be performed. In some examples, the light projected in block 810 may be on one or more different wavelengths than the one or more wavelengths the light may be projected in block 820. In such examples, the one or more different wavelengths may be used to effectively separate the reflections of the light projected by the one or more SMI eye tracking sensors from the reflections of the light projected by the one or more VCSEL eye tracking pattern projectors (this may occur in some examples regardless of whether blocks 850 and 860 are integrated in an optional block 864 and / or an optional block 875).

[0152] The dotted-line block 875, as mentioned above, indicates that, optionally in some examples, the non-image-based eye tracking in block 850 using the reflections of the light projected by the one or more SMI eye tracking sensors in block 810 may be integrated with the image-based and / or camera-based eye tracking in block 860 using the reflections of the light projected by the one or more quasi-LED VCSEL eye tracking pattern projectors in block 820. In some examples, the results of the non-image-based eye tracking in block 850 and the results of the image-based eye tracking in block 860 may be integrated after blocks 850 and / or 860 as a separate process. In some examples, the non-image-based eye tracking in block 850 and the image-based eye tracking in block 860 may be integrated either as part of performing block 850, block 860, and / or any combination thereof.

[0153] In some examples, the one or more SMI eye tracking sensors may be performing blocks 810, 830, and 835 substantially continually and / or at a much higher rate than the eye tracking cameras may be performing blocks 840 and 845 and / or the one or more quasi-LED VCSEL eye tracking pattern projectors may be performing block 820. In such examples, the SMI-based eye tracking of block 850 may be employed to continually / periodically update eye movement / position between image captures by the one or more eye tracking camera(s) in block 840 and / or performances of the image-based / camera- based eye tracking in block 860. In some examples, the image data generated in block 840and / or the image-based eye tracking performed in block 860 may be employed to update and / or generate the eye model used to direct, focus, and / or otherwise control the performance of blocks 810, 830, and / or 835 by the one or more one or more SMI eye tracking sensors.

[0154] In some examples, the method 800 may include estimating, updating, calculating, and / or otherwise determining any parameter, quality, quantity, and / or feature of the user’s eye, viewpoint, relative position and posture in regards to the external environment, relative position and viewpoint in regard to the display of any computer-generated images, etc., as would be understood by one of ordinary skill in the art. In some examples, the method 800 may include estimating, updating, calculating, and / or otherwise determining a gaze vector or position of the user’s eye; a vector indicating how a user’s head is positioned in respect to the display; a vector indicating how a user’s eye viewpoint intersects the display; and / or a vector indicating how a user’s eye viewpoint may have moved in relation to the display. In some examples, the method 800 may include estimating, updating, calculating, and / or otherwise determining a specific eye movement such as, e.g., smooth pursuit, saccade, fixation, nystagmus, and / or blinking. In some examples, the method 800 may include estimating, updating, calculating, and / or otherwise determining any other eye-related events, such as, for example, opening an eye, closing an eye, making a particular sequence of eye movements, gazing in a particular direction, etc., as would be understood by one of ordinary skill in the art. In some examples, the method 800 may include estimating, updating, calculating, and / or otherwise determining based on information / data from any other components in the near-eye display device.

[0155] Figure 9 is a flowchart illustrating a method for manufacturing a combined SMI eye tracking sensor and VCSEL eye tracking pattern projector chip which may be used in a near-eye display device according to examples of the present disclosure. The method 900 shown in Figure 9 is provided by way of example and may only be one part of an entire manufacturing process, as would be understood by one of ordinary skill in the art. The method 900 may further omit parts of any process, procedure, ongoing operation, method, etc., involved in manufacturing a combined SMI / quasi-LED VCSEL eye tracking chip not germane to examples of the present disclosure, as would be understood by one of ordinary skill in the art. Each block shown in Figure 9 may further represent one or more steps, processes, methods, or subroutines, as would be understood by one of ordinary skill in the art. In some examples, the processes in the blocks of Figure 9 may overlap and / or may occur substantially simultaneously. For the sake of convenience and ease of explanation, the blocks in Figure 9 may refer to the components shown in the Figures described herein; however, the method 900 is not limited in any way to the components, apparatuses, and / or constructions described and / or shown in any of the Figures herein.

[0156] As mentioned further above, the method 900 of manufacturing may employlithography, including, for example, such techniques as photolithography (including, e.g., optical lithography and quantum optical lithography), scanning lithography (including, e.g., electron-beam lithography, scanning probe lithography, proton beam writing, charged particle lithography, etc.), soft lithography (including, e.g., polydimethylsiloxance (PDMS) lithography, microcontact printing, multilayer soft lithography, etc.), nanoimprint lithography, magnetolithography, nanofountain drawing, nanosphere lithography, neural particle lithography, plasmonic lithography, stencil lithography, and / or any other past, present, or future lithographic technique suitable for fabricating a chip in accordance with the present disclosure, as would be understood by one of ordinary skill in the art.

[0157] In some examples, regardless of whether mentioned specifically herein, the method 900 of manufacturing may employ any of the various techniques of wafer processing, die preparation, packaging, and / or testing. In some examples, the method 900 of manufacturing may employ wafer processing techniques including, but not limited to, wet cleans (including, e.g., wafer scrubbing and / or cleaning by solvents and / or solutions); surface passivation; ion implantation; molecular beam epitaxy (MBE); plasma ashing; thermal treatments (such as, e.g., rapid thermal anneal, furnace anneals, thermal oxidation, etc.); Electrochemical Deposition (ECD) and / or electroplating; Chemical Vapor Deposition (CVD); Atomic Layer Deposition (ALD); Physical Vapor Deposition (PVD) (including, e.g., sputtering, evaporation, etc.); Chemical Mechanical Polishing (CMP); photolithographic techniques (such as, e.g., photoresist coating, photoresist baking, edge bead removal, exposure, development, Post Exposure Baking (PEB), etc.); etching or microfabrication (such as, e.g., dry or plasma etching, including Reactive Ion Etching (RIE) and Atomic Layer Etching (ALE), and / or wet etching, including, e.g., a buffered oxide etch); laser lift-off; wafer testing, etc., as would be understood by one of ordinary skill in the art.

[0158] In some examples, the method 900 of manufacturing may employ die preparation techniques including, but not limited to, through-silicon via (TSV), wafer mounting with dicing tape, wafer backgrinding and polishing, wafer bonding and stacking, redistribution layer manufacture, wafer bumping, die cutting, wafer dicing, etc., as would be understood by one of ordinary skill in the art. In some examples, the method 900 of manufacturing may employ integrated circuit packaging techniques including, but not limited to, die attachment, bonding (such as, e.g., wire bonding, thermosonic bonding, flip chip or Tape Automated Bonding (TAB)), encapsulation (such as, e.g., integrated heat spreader (HIS) installation, molding, baking, electroplating, laser marking, silkscreen printing, trimming and forming, and the like), etc., as would be understood by one of ordinary skill in the art.

[0159] At block 910, the method 900 may start manufacturing a combined SMI eye tracking sensor and VCSEL eye tracking pattern projector chip (hereinafter, “the combined SMI / quasi-LED VCSEL eye tracking chip”) by epitaxially depositing semiconductor and / ordielectric layers on a substrate. In some examples, the substrate (such as the substrate 405 in Figure 4) may be Gallium Arsenide (GaAs), Aluminum Arsenide (AlAs), any of the various types of silicon (e.g., Silicon Dioxide (SiO2), Silicon Nitride (SiN), etc.), etc., as would be understood by one of ordinary skill in the art.

[0160] At block 920, the method 900 may provide one or more layers constituting a bottom reflector layer of the combined SMI / quasi-LED VCSEL eye tracking chip. In some examples, the bottom reflector layer may include the bottom reflector layer 411 of the SMI sensor 410 and the bottom reflector layer 511 of the VCSEL quasi-LED projector 550 in Figure 5. In some examples, the bottom reflector layer of the combined SMI / quasi-LED VCSEL eye tracking chip may include a distributed Bragg reflector (DBR) layer.

[0161] At block 930, the method 900 may provide one or more layers constituting the photodetector (PD) layer of the combined SMI / quasi-LED VCSEL eye tracking chip. In some examples, the one or more layers may include the PD layer 412 of the SMI sensor 410 in Figure 4 and the PD layer 512 of the VCSEL quasi-LED projector 550 in Figure 5. In some examples, the PD layer may include a light sensor on the SMI eye tracking sensor portion of the combined SMI / quasi-LED VCSEL eye tracking chip. In some examples, the PD layer may be provided uniformly across the portion forming the quasi-LED VCSEL eye tracking pattern projector. In such examples, the PD layer under the quasi-LED VCSEL eye tracking pattern projector may never be enabled, utilized, and / or completed for usage. In some examples, the PD layer may include, for example, a photodiode, a photodetector (such as, e.g., a silicon- based photodetector), and / or any other suitable light detecting element, as would be understood by one of ordinary skill in the art. In some examples, the light sensor may include a photon absorption layer, such as, e.g., an Indium Gallium Arsenide (InGaAs) layer.

[0162] At block 940, the method 900 may provide one or more layers constituting a middle reflector layer of the combined SMI / quasi-LED VCSEL eye tracking chip. In some examples, the middle reflector layer may include the middle reflector layer 413 / 453 of the combined SMI / quasi-LED VCSEL chip 400 in Figure 4 and the middle reflector layer 513 / 553 of the combined SMI / quasi-LED VCSEL chip 500 in Figure 5. In some examples, the middle reflector layer of the combined SMI / quasi-LED VCSEL eye tracking chip may include an n- doped distributed Bragg reflector (n-DBR) layer.

[0163] At block 950, the method 900 may provide one or more layers constituting the active region / optical cavity of the combined SMI / quasi-LED VCSEL eye tracking chip. In some examples, the one or more layers constituting the active region / optical cavity may include the optical cavity 415 of the SMI sensor 410 and the optical cavity 455 of the VCSEL quasi-LED projector 450 in Figure 4, as well as the optical cavity 515 of the SMI sensor 510 and the optical cavity 555 of the VCSEL quasi-LED projector 550 in Figure 5. In some examples, the one or more layers constituting the active region / optical cavity may include a photonabsorption layer, such as, e.g., an Indium Gallium Arsenide (InGaAs) layer, and / or a resonant optical cavity. In some examples, the one or more layers constituting the active region / optical cavity may include one or more quantum wells, in single quantum well or multiple quantum well (MQW) structures. In some examples, the one or more layers constituting the active region / optical cavity may include an aperture through which laser light may be guided and through which a current applied to the SMI sensor and / or the quasi-LED VCSEL projector may be constricted.

[0164] At block 960, the method 900 may provide one or more layers constituting a top reflector layer of the combined SMI / quasi-LED VCSEL eye tracking chip. In some examples, the top reflector layer may include the top reflector layers 417 and 457 of the SMI sensor 410 and VCSEL quasi-LED projector 450, respectively, in Figure 4 and the top reflector layers 517 and 557 of the SMI sensor 510 and VCSEL quasi-LED projector 550, respectively, in Figure 5. At this stage, the top reflector layers 457 and 557 of the VCSEL quasi-LED projectors 450 and 550, respectively, may be whole (i.e. , the etched portion 459 / 559 has not been etched out yet). In some examples, the top reflector layer of the combined SMI / quasi- LED VCSEL eye tracking chip may include a p-doped distributed Bragg reflector (p-DBR) layer.

[0165] At block 970, the method 900 may etch away at least a portion of the top reflector layer of the quasi-LED VCSEL eye tracking pattern projector portion of the combined SMI / quasi-LED VCSEL chip. In some examples, the etched away portion may be similar to the etched portion 459 above the VCSEL quasi-LED projector 450 in Figure 4 and the etched portion 559 above the VCSEL quasi-LED projector 550 in Figure 5. In some examples, block 970 may etch away more or less layers from the portion of the combined SMI / quasi-LED VCSEL eye tracking chip to be employed as VCSEL eye tracking quasi-LED pattern projector. In some examples, sub-layers within the top reflector layer of block 950 may not be etched away but rather remain to be employed in the functioning of the VCSEL eye tracking quasi- LED pattern projector in the combined SMI / quasi-LED VCSEL eye tracking chip.

[0166] In some examples of block 970, a hole may be cut through the top reflector layer of the quasi-LED VCSEL projector formed in block 960 which allows the quasi-LED VCSEL eye tracking pattern projector to provide a wide beam emission similar to an LED.

[0167] As previously discussed, when a portion above the VCSEL quasi-LED projector is etched away from the top of the combined SMI / quasi-LED VCSEL chip in block 970, the SMI sensor portion may be protected by a layer of photoresist while the top layer of the VCSEL quasi-LED projector is etched. In some examples, etching methods such as Inductively Coupled Plasma (ICP) etching may be used for wet and / or dry etching. In some examples, during the fabrication of the layers of the combined SMI / quasi-LED VCSEL chip, additional processes and methods may be performed on the VCSEL quasi-LED projector portion whilethe SMI sensor portion is untouched and / or protected by a coating or other means from the processes and methods being performed on the VCSEL quasi-LED projector. These extra processes and methods may to enable the VCSEL quasi-LED projector to project a wide emission beam similar to a light pattern emitted by an LED in an eye tracking system of a near-eye display device.

[0168] As would be understood by one of ordinary skill in the art, any of the layers named in the method 900 of Figure 9 may, in some examples, include many constituent layers and / or may be integrated together into larger layers. For instance, the top reflector layer and / or the bottom reflector layer may include many sub-layers; conversely, there may be more reflector layers than just the top and bottom reflector layers. In some examples, electrical contacts may be included in any of the layers named in the method 900 of Figure 9 for purposes of control, management, and power of components / layers of the combined SMI / quasi-LED VCSEL eye tracking chip. For instance, the method 900 may provide a top surface for the combined SMI / quasi-LED VCSEL eye tracking chip, which may include, for example, an emitting surface layer, a passivation layer, a surface grating (such as, e.g., a diffractive grating, relief grating, high-contrast grating, etc.), a metasurface and / or metalens, a micromechanical system (MEMS), a liquid lens, a mask (such as, e.g., a phase mask), etc., as would be understood by one of ordinary skill in the art. In some examples, the top layer is a mask suited for projecting the light from the SMI eye tracking sensor.

[0169] According to examples, a combined SMI eye tracking sensor and quasi-LED VCSEL eye tracking pattern projector chip is described herein. One or more methods / systems for using a combined SMI eye tracking sensor and VCSEL eye tracking quasi-LED pattern projector chip are also described herein. One or more methods / systems for manufacturing a combined SMI eye tracking sensor and VCSEL eye tracking pattern quasi-LED projector chip are also described herein. A non-transitory computer-readable storage medium may have an executable stored thereon, which when executed instructs a processor to perform any of the methods described herein.

[0170] 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 the disclosure. 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.

[0171] The figures and description are not intended to be restrictive. The terms andexpressions 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 "example' is not necessarily to be construed as preferred or advantageous over other embodiments or designs.

[0172] 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

CLAIMS1 . An integrated circuit for a near-eye display device, comprising: a self mixing interferometer (SMI) eye tracking sensor to: project a beam of light onto an eye, receive first reflected light from the eye by the beam of light, modulate the first reflected light, and provide an electrical signal corresponding to the modulated light, wherein non-image-based eye tracking is performed based on the electrical signal; and a vertical cavity self emitting laser (VCSEL) eye tracking pattern projector to: project a pattern onto the eye, wherein image-based eye tracking is performed based on second reflected light from the eye by the pattern projected by the VCSEL eye tracking pattern projector.

2. The integrated circuit of claim 1 , wherein the SMI eye tracking sensor comprises: a top reflector layer; an optical cavity; a middle reflector layer; a photodetector (PD) layer to receive the modulated light and provide the electrical signal corresponding to the modulated light; and a bottom reflector layer; preferably wherein the PD layer in the SMI eye tracking sensor comprises at least one of a photodetector or a photodiode.

3. The integrated circuit of claim 1 or 2, wherein the VCSEL eye tracking pattern projector comprises: a top reflector layer; an optical cavity; and a middle reflector layer.

4. The integrated circuit of claim 3, wherein the optical cavity of the VCSEL eye tracking pattern projector comprises: a laser cavity operable to project a wide emission beam.

5. The integrated circuit of claim 4, wherein the laser cavity comprises: a tapered laser cavity.

6. The integrated circuit of claim 4 or 5, wherein the VCSEL eye tracking pattern projector further comprises: a micromechanical system (MEMS) to alter a shape of the laser cavity.

7. The integrated circuit of any of claims 3 to 6, wherein the bottom reflector layer comprises a distributed Bragg reflector (DBR);preferably wherein the DBR comprises a chirped distributed Bragg reflector (DBR).

8. The integrated circuit of any preceding claim, wherein the VCSEL eye tracking pattern projector comprises: an increased diameter aperture to project a wide emission beam; and / or a metasurface to project a wide emission beam9. The integrated circuit of any preceding claim, wherein the integrated circuit is disposed within a lens of the near-eye display device.

10. The integrated circuit of any preceding claim, wherein the integrated circuit is disposed on a frame of the near-eye display device.

11. A method of eye tracking in a near-eye display device, comprising: projecting, by a self mixing interferometer (SMI) eye tracking sensor in an integrated circuit (IC), a beam of light towards an eye of a user of the near-eye display device; projecting, by a vertical cavity self emitting laser (VCSEL) eye tracking pattern projector in the integrated circuit (IC), a pattern of light towards the eye of the user; receiving and modulating, by the self mixing interferometer (SMI) eye tracking sensor, first reflected light from the eye of the user by the beam of light projected by the self mixing interferometer (SMI) eye tracking sensor; providing, by the self mixing interferometer (SMI) eye tracking sensor, an electrical signal corresponding to the received and modulated light; receiving, by an eye tracking camera, second reflected light from the eye of the user by the pattern of light projected by the vertical cavity self emitting laser (VCSEL) eye tracking pattern projector; providing, by the eye tracking camera, data corresponding to the received second reflected light; performing image-based eye tracking based on the data provided by the eye tracking camera; and performing non-image eye tracking based on the electrical signal provided by the self mixing interferometer (SMI) eye tracking sensor.

12. The method of eye tracking of claim 11 , further comprising: performing eye tracking by integrating the image-based eye tracking and the non-image- based eye tracking.

13. A method of manufacturing an eye tracking sensor for a near-eye display device, comprising: providing a substrate; providing a bottom reflector layer on the substrate; providing a photodetector (PD) layer above the bottom reflector layer; providing a middle reflector layer above the PD layer;providing one or more layers above the middle reflector layer to provide a first optical cavity on a first portion and a second optical cavity on a second portion; providing a top reflector layer above the one or more layers having the first optical cavity on the first portion and the second optical cavity on the second portion; and etching away at least a portion of the top reflector layer on the second portion; wherein the bottom reflector layer, the PD layer, the middle reflector layer, the first optical cavity, and the top reflector layer on the first portion comprise a self mixing interferometer (SMI); and wherein the middle reflector layer, the second optical cavity, and the etched top reflector layer on the second portion comprise a vertical cavity self emitting laser (VCSEL).

14. The method of manufacturing of claim 13, further comprising: providing a protective coating on the first portion before the step of etching away on the second portion.

15. The method of manufacturing of claim 13 or 14, wherein the second optical cavity comprises a laser cavity operable to project a wide emission beam; preferably wherein the step of providing one or more layers above the middle reflector layer to provide a first optical cavity on a first portion and a second optical cavity on a second portion comprises: providing the second optical cavity as a tapered laser cavity; further preferably further comprising: providing a micromechanical system (MEMS) to alter a shape of the laser cavity.

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