Sensing component for measuring displacement of an optical module

Abstract

Sensing components for measuring optical module displacement are provided. A head-mounted device includes a first optical module; a second optical module; a flexible support structure attaching the first optical module to the second optical module; an emitter disposed on the first optical module and configured to emit diffuse light; a detector including a patterned mask having an array of openings and an image sensor covered by the patterned mask structure and configured to receive at least a portion of the diffuse light that propagates through the array of openings in the patterned mask to sense one or more corresponding diffraction patterns; and a control circuit configured to analyze the one or more diffraction patterns sensed by the image sensor of the detector to determine a relative pose displacement between the first optical module and the second optical module. The head-mounted device can also include beam splitters and associated detectors for sensing interference patterns and beam spots.

Description

[0001] This application claims priority to U.S. Patent Application No. 19 / 637,203, filed April 2, 2026, and U.S. Provisional Patent Application No. 63 / 793,443, filed April 23, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates generally to electronic devices, and more specifically to electronic devices such as head-mounted devices. Background Technology

[0003] Electronic devices, such as head-mounted devices, may have a camera for capturing video feeds of an external scene, a graphics rendering engine for generating virtual content, and one or more displays for presenting the captured video feeds and / or the generated virtual content to a user. The displays may include a left optical module for outputting content to the left eye and a right optical module for outputting content to the right eye.

[0004] To correctly display content to the user's left and right eyes, the relative positioning and orientation of the left and right optical modules must be known. Determining the relative positioning and orientation of the left and right optical modules during normal operation can be challenging. It is against this backdrop that the implementation scheme described in this paper was developed. Summary of the Invention

[0005] One aspect of this disclosure provides a method of operating a head-mounted device, the head-mounted device comprising: a first optical module configured to output content to a first eye-adaptive region; a second optical module configured to output content to a second eye-adaptive region; a support structure attaching the first optical module to the second optical module, wherein the support structure at least partially includes a flexible portion that allows the first and second optical modules to move relative to each other when flexed; an emitter disposed on the first optical module and configured to emit diffuse light; a detector including a patterned mask having a plurality of openings and an image sensor configured to receive propagation of diffuse light through at least a portion of the plurality of openings in the patterned mask to sense one or more corresponding diffraction patterns; and control circuitry configured to analyze the one or more diffraction patterns sensed by the image sensor of the detector to determine a relative tactile displacement between the first and second optical modules.

[0006] One aspect of this disclosure provides a head-mounted device comprising: a first optical module configured to output content to a first eye-adaptive region; a second optical module configured to output content to a second eye-adaptive region; a support structure attaching the first optical module to the second optical module, wherein the support structure at least partially includes a flexible portion that allows the first and second optical modules to move relative to each other upon flexing; a light source disposed on the first optical module and configured to output a coherent beam; and a beam splitter. A beam splitter is configured to split a coherent beam into a first beam and a second beam; a reflector is configured to reflect the first beam; a semi-reflector is disposed on a second optical module and configured to reflect a portion of the second beam; a first detector is configured to sense an interference pattern generated by the phase shift difference between the portion of the first beam reflected from the reflector and the portion of the second beam reflected from the semi-reflector; and control circuitry is configured to analyze the interference pattern sensed by the first detector to determine a relative translational displacement between the first and second optical modules. The device may also include a second detector configured to sense a portion of the second beam transmitted through the semi-reflector. The first detector may be configured to sense a first beam spot associated with a superimposed beam comprising the portion of the first beam reflected from the reflector and the portion of the second beam reflected from the semi-reflector, while the second detector may be configured to sense a second beam spot associated with the portion of the second beam transmitted through the semi-reflector. The control circuit can be configured to analyze the position of the first beam spot in the first detector and the position of the second beam spot in the second detector to determine the relative rotational displacement between the first optical module and the second optical module.

[0007] One aspect of this disclosure provides a head-mounted device comprising: a first optical module configured to output content to a first eye-adaptive region; a second optical module configured to output content to a second eye-adaptive region; a support structure attaching the first optical module to the second optical module, wherein the support structure at least partially includes a flexible portion that allows the first and second optical modules to move relative to each other upon flexing; a rigid structure extending between the first and second optical modules; a first angle detector disposed at a first location on the rigid structure; a second angle detector disposed at a second location on the rigid structure; a first light source disposed on the first optical module and configured to output a first coherent light beam toward the first angle detector; a second light source disposed on the second optical module and configured to output a second coherent light beam toward the second angle detector; and control circuitry configured to analyze the position of the first light beam spot sensed by the first angle detector and the position of the second light beam spot sensed by the second angle detector to determine a relative rotational displacement between the first and second optical modules. The first angle detector may include a first image sensor and one or more grating structures disposed above the first image sensor, while the second angle detector may include a second image sensor and one or more grating structures disposed above the second image sensor. The first light source may be further configured to output a linearly polarized laser beam toward the first angle detector, and the second light source may be further configured to output a linearly polarized laser beam toward the second angle detector. Attached Figure Description

[0008] Figure 1 This is a top view of an exemplary head-mounted device based on some implementation schemes.

[0009] Figure 2 These are schematic diagrams of exemplary electronic devices based on some implementation schemes.

[0010] Figure 3 This is an illustration showing how two optical modules in a head-mounted device according to some embodiments can be joined by a support structure with flexible parts.

[0011] Figure 4 This is a top view of an exemplary head-mounted device according to some implementations, showing how the transmitter and detector can be respectively mounted on a first optical module and a second optical module.

[0012] Figure 5A This is a front view of an exemplary transmitter based on some implementation schemes.

[0013] Figure 5BThis is a side view of an exemplary transmitter based on some implementation schemes.

[0014] Figure 6 This is a side view of an exemplary detector based on some implementation schemes.

[0015] Figure 7 It can be included as, according to some implementation schemes. Figure 6 A front view of an exemplary patterned mask structure representing a portion of a detector of the type shown.

[0016] Figure 8 This is an example based on some implementation schemes. Figures 3 to 7 A side view showing how transmitters and detectors of the type shown can be used to measure translational displacement in the YZ plane.

[0017] Figure 9 This is an example based on some implementation schemes. Figures 3 to 7 A side view showing how transmitters and detectors of the type shown can be used to measure translational displacement in the X direction.

[0018] Figure 10 It is for use according to some implementation schemes. Figures 3 to 9 A flowchart illustrating the steps of using a transmitter and detector of the type shown to measure the relative posture between a first optical module and a second optical module.

[0019] Figure 11 This is a top view of an exemplary head-mounted device according to some implementations, showing how both the transmitter and detector can be positioned on one of two optical modules.

[0020] Figure 12 This is a side view of an exemplary transmitter with a patterned mask structure according to some implementation schemes.

[0021] Figures 13A to 13E It is a front view of an exemplary mask with a single opening according to some implementation schemes.

[0022] Figures 14A to 14G This is a front view of an exemplary mask with an array of openings according to some implementation schemes.

[0023] Figure 15 This is a top view of an exemplary head-mounted device according to some embodiments, the exemplary head-mounted device having a plurality of transmitters disposed at a first optical module and a plurality of detectors disposed at a second optical module.

[0024] Figure 16This is a top view of an exemplary head-mounted device according to some embodiments, the exemplary head-mounted device having a first transmitter and a first detector disposed at a first optical module, and having a second detector and a second transmitter disposed at a second optical module.

[0025] Figure 17 This is a top view of an exemplary head-mounted device according to some embodiments, the exemplary head-mounted device having a light source disposed at a first optical module, a first detector disposed between the first optical module and a second optical module, and a second detector disposed at the second optical module.

[0026] Figure 18 This is a top view of an exemplary head-mounted device according to some embodiments, the exemplary head-mounted device having a light source and a first detector disposed at a first optical module, and a second detector disposed at a second optical module.

[0027] Figure 19 This is a top view of an exemplary head-mounted device according to some embodiments, the exemplary head-mounted device having a light source disposed at a first optical module and two detectors disposed at a second optical module.

[0028] Figure 20 It is for use according to some implementation schemes. Figures 17 to 19 A flowchart illustrating the steps of using a light source of the type shown and two detectors to measure the relative posture between a first optical module and a second optical module.

[0029] Figure 21 This is a top view of an exemplary head-mounted device according to some embodiments, the exemplary head-mounted device having a first light source disposed at a first optical module, a second light source disposed at a second optical module, and corresponding angle detectors facing the first light source and the second light source and disposed on a rigid structure.

[0030] Figure 22 It is based on some implementation plans. Figure 21 A side view of an illustrative angle detector of the type shown.

[0031] Figure 23 It can be included as, according to some implementation schemes. Figure 22 A front view of an exemplary grating structure, part of an angle detector. Detailed Implementation

[0032] Figure 1 A top view of an illustrative head-mounted device is shown. (See attached image.) Figure 1As shown, a head-mounted device, such as electronic device 10, may have a head-mounted support structure, such as a housing 12. The housing 12 may include portions (e.g., head-mounted support structure 12T) for allowing the device 10 to be worn on a user's head. The support structure 12T may be formed of fabric, polymer, metal, and / or other materials. The support structure 12T may form a strap or other head-mounted support structure to help support the device 10 on the user's head. The main support structure of the housing 12 (e.g., a head-mounted housing such as a main housing portion 12M) may support electronic components such as a display 14.

[0033] The main housing portion 12M may include a housing structure formed of metal, polymer, glass, ceramic, and / or other materials. For example, the housing portion 12M may have a housing wall on the front F formed of a rigid polymer or other rigid support structure, and housing walls on adjacent top, bottom, left, and right sides, and these rigid walls may optionally be covered with electronic components, fabric, leather, or other soft materials. The housing portion 12M may also have an internal support structure, such as a frame (chassis) and / or a structure that performs multiple functions, such as controlling airflow and heat dissipation while providing structural support.

[0034] The walls of the housing portion 12M can enclose the internal components 38 in the internal region 34 of the device 10 and separate the internal region 34 from the environment surrounding the device 10 (external region 36). The internal components 38 may include integrated circuits, actuators, batteries, sensors, and / or other circuitry and structures for the device 10. The housing 12 can be configured to be worn on a user's head and can form eyeglasses, eyeglasses, hats, masks, helmets, goggles, and / or other head-mounted devices. Configurations in which the housing 12 forms goggles are sometimes described herein as examples.

[0035] The front F of the housing 12 faces outwards away from the user's head and face. The opposite back R of the housing 12 faces the user. A portion of the housing 12 located on the back R (e.g., a portion of the main housing 12M) may form a cover, such as a cover 12C (sometimes referred to as a curtain). The presence of the cover 12C on the back R helps to conceal the internal housing structure, internal components 38, and other structures in the internal area 34 from being seen by the user.

[0036] Device 10 may have one or more cameras, such as Figure 1Camera 46. Mounted on the front F and facing outwards (towards the front of device 10 and away from the user), camera 46 may be referred to herein as an outward-facing camera, a forward-facing camera, or a front-facing camera. Camera 46 can capture visual ranging information, image information processed to locate objects in the user's field of view (e.g., to enable virtual content to be properly registered relative to real-world objects), image content to be displayed to the user of device 10 in real time, and / or other suitable image data. For example, an outward-facing camera (front-facing camera) may allow device 10 to monitor the movement of device 10 relative to its surrounding environment (e.g., the camera may be used as part of a visual ranging system or a visual-inertial ranging system). An outward-facing camera can also be used to capture images of the environment displayed to the user of device 10. If desired, images from multiple outward-facing cameras can be merged with each other and / or outward-facing camera content can be merged with computer-generated content for the user.

[0037] Device 10 may have any suitable number of cameras 46. For example, device 10 may have K cameras, where the value of K is at least one, at least two, at least four, at least six, at least eight, at least ten, at least 12, less than 20, less than 14, less than 12, less than 10, 4-10, or other suitable values. Cameras 46 may be sensitive at infrared wavelengths (e.g., camera 46 may be an infrared camera), sensitive at visible wavelengths (e.g., camera 46 may be a visible camera), and / or sensitive at other wavelengths. If desired, cameras 46 may be sensitive at both visible and infrared wavelengths.

[0038] Device 10 may have a left optical module and a right optical module 40. Optical module 40 supports electronic components and optical components such as light-emitting components and lenses, and is therefore sometimes referred to as an optical assembly, optical system, optical component support structure, lens and display support structure, electronic component support structure, or housing structure. Each optical module may include a corresponding display 14, lens 30, and support structure such as support structure 32. Support structure 32 may sometimes be referred to as a lens support structure, optical component support structure, optical module support structure, or optical module portion, or lens barrel, and may include a hollow cylindrical structure with an open end or other support structure for accommodating display 14 and lens 30. Support structure 32 may, for example, include a left lens barrel supporting the left display 14 and left lens 30 and a right lens barrel supporting the right display 14 and right lens 30.

[0039] Display 14 may include a pixel array or other display devices to generate images. Display 14 may include, for example, organic light-emitting diode pixels formed on a substrate having thin-film circuitry and / or formed on a semiconductor substrate, pixels formed from a crystal semiconductor die, liquid crystal display pixels, scanning display devices, and / or other display devices for generating images.

[0040] Lens 30 may include one or more lens elements for providing image light from display 14 to a corresponding eye-friendly area 13. The lens may be implemented using a refractive glass lens element, a mirror lens structure (reflective refractive lens), a Fresnel lens, a holographic lens, and / or other lens systems.

[0041] When the user's eyes are in the eye-adaptation zone 13, the display (display panel) 14 operates together to form the display of the device 10 (e.g., the user's eyes can view the images provided by the corresponding left and right optical modules 40 in the eye-adaptation zone 13, thus creating a stereoscopic image for the user). When the user views the display, the left image from the left optical module is fused with the right image from the right optical module.

[0042] It may be desirable to monitor the user's eyes when they are within the eye-fitting zone 13. For example, it may be desirable to use a camera to capture an image of the user's iris (or another part of the user's eye) for user authentication. It may also be desirable to monitor the direction of the user's gaze. Gaze tracking information can be used as a form of user input and / or can be used to determine where in the image content resolution should be locally enhanced in a small-foveal imaging system. To ensure that device 10 can capture a satisfactory eye image when the user's eyes are within the eye-fitting zone 13, each optical module 40 may be provided with a camera (such as camera 42) and one or more light sources (such as light-emitting diodes 44) or other light-emitting devices (such as lasers, lamps, etc.). Camera 42 and light-emitting diodes 44 can operate at any suitable wavelength (visible light, infrared light, and / or ultraviolet light). For example, diode 44 may emit infrared light that is invisible (or nearly invisible) to the user. This allows for continuous eye monitoring without interfering with the user's ability to view the image on display 14.

[0043] Figure 2 The diagram illustrates an exemplary electronic device such as a head-mounted device or other wearable device. Figure 2 Device 10 can operate as a standalone device, and / or resources of device 10 can be used to communicate with external electronic equipment. For example, communication circuitry in device 10 can be used to transmit user input information, sensor information, and / or other information to external electronic devices (e.g., wirelessly or via a wired connection). Each of these external devices may include Figure 2 The device 10 is a component of the type shown.

[0044] like Figure 2As shown, a head-mounted device such as device 10 may include control circuitry 20. Control circuitry 20 may include storage and processing circuitry for supporting the operation of device 10. This storage and processing circuitry may include storage devices such as non-volatile memory (e.g., flash memory or other electrically programmable read-only memory configured to form a solid-state drive), volatile memory (e.g., static or dynamic random access memory), etc. One or more processors in control circuitry 20 may be used to acquire input from sensors and other input devices and to control output devices. Processing circuitry may be based on one or more processors (e.g., microprocessors, microcontrollers, digital signal processors, baseband processors and other wireless communication circuitry, power management units, audio chips, application-specific integrated circuits, etc.). During operation, control circuitry 20 may use display 14 and other output devices to provide visual output and other outputs to the user. Control circuitry 20 may be configured to perform operations within device 10 using hardware (e.g., dedicated hardware or circuitry), firmware, and / or software. Software code for performing operations within device 10 may be stored on storage circuitry (e.g., a non-transitory (tangible) computer-readable storage medium storing the software code). The software code may sometimes be referred to as program instructions, software, data, commands, or code. The stored software code can be executed by the processing circuitry within circuit 20.

[0045] To support communication between device 10 and external equipment, control circuit 20 may use communication circuit 22 for communication. Circuit 22 may include antenna, radio frequency transceiver circuitry, and other wireless communication circuitry and / or wired communication circuitry. Circuit 22 (sometimes referred to as control circuitry and / or control and communication circuitry) may support bidirectional wireless communication between device 10 and external equipment (e.g., companion devices such as computers, cellular phones or other electronic devices, accessories such as point devices, controllers, computer styluses or other input devices, speakers or other output devices, etc.) via a wireless link.

[0046] For example, circuit 22 may include radio frequency transceiver circuitry, such as a wireless LAN transceiver circuitry configured to support communication via a wireless LAN link, a near-field communication transceiver circuitry configured to support communication via a near-field communication link, a cellular transceiver circuitry configured to support communication via a cellular telephone link, or a transceiver circuitry configured to support communication via any other suitable wired or wireless communication link. For example, it may be via Bluetooth. ® Link, WiFi ®The link, a wireless link operating at frequencies between 10 GHz and 400 GHz, a 60 GHz link or other millimeter-wave link, a cellular phone link, or other wireless communication link supports wireless communication. Device 10 may, if desired, include power circuitry for transmitting and / or receiving wired and / or wireless power, and may include a battery or other energy storage device. For example, device 10 may include coils and rectifiers to receive wireless power supplied to the circuitry in device 10.

[0047] Device 10 may include input-output devices, such as device 24. Input-output device 24 may be used to acquire user input, to acquire information about the user's surrounding environment, and / or to provide output to the user. Device 24 may include one or more displays, such as display 14. Display 14 may include one or more display devices, such as an organic light-emitting diode display panel (a panel on which organic light-emitting diode pixels are formed on a polymer substrate or silicon substrate containing pixel control circuitry), a liquid crystal display panel, a microelectromechanical system display (e.g., a two-dimensional mirror array or scanning mirror display device), a display panel having a pixel array formed from crystalline semiconductor light-emitting diode dies (sometimes referred to as microLEDs), and / or other display devices.

[0048] The sensor 16 in the input-output device 24 may include force sensors (e.g., strain gauges, capacitive force sensors, resistive force sensors, etc.), audio sensors (such as microphones), touch and / or proximity sensors (such as capacitive sensors, touch sensors such as those forming buttons, touchpads, or other input devices), and other sensors. If desired, the sensor 16 may include optical sensors (such as optical sensors that emit and detect light), ultrasonic sensors, optical touch sensors, optical proximity sensors and / or other touch and / or proximity sensors, monochrome and color ambient light sensors, image sensors (e.g., cameras), fingerprint sensors, iris scanning sensors, retinal scanning sensors and other biometric sensors, temperature sensors, sensors for measuring three-dimensional non-contact gestures (“air gestures”), pressure sensors, sensors for detecting position, orientation, and / or motion of the device 10 and / or information about the user’s head posture (e.g., accelerometers, magnetic sensors such as compasses). Sensors, gyroscopes, and / or inertial measurement units containing some or all of these sensors; health sensors such as blood oxygen sensors, heart rate sensors, blood flow sensors, and / or other health sensors; radio frequency sensors; 3D camera systems such as depth sensors (e.g., structured light sensors and / or depth sensors based on stereo imaging devices that capture 3D images); and / or optical sensors such as self-mixing sensors and light detection and ranging (laser) sensors that acquire time-of-flight measurements (e.g., time-of-flight cameras); humidity sensors; moisture sensors; gaze tracking sensors; electromyography sensors that sense muscle activation; facial sensors; and / or other sensors. In some arrangements, device 10 may use sensor 16 and / or other input-output devices to acquire user input. For example, buttons may be used to acquire button press input, touch sensors overlapping the display may be used to acquire user touchscreen input, touchpads may be used to acquire touch input, microphones may be used to acquire audio input (e.g., voice commands), accelerometers may be used to monitor when a finger contacts an input surface and thus may be used to acquire finger press input, etc.

[0049] If desired, electronic device 10 may include additional components (see, for example, other devices 18 in input-output device 24). Additional components may include tactile output devices, actuators for moving the movable housing structure, audio output devices such as speakers, light-emitting diodes for status indicators, light sources such as light-emitting diodes for illuminating portions of the housing and / or display structure, other optical output devices, and / or other circuitry for acquiring input and / or providing output. Device 10 may also include batteries or other energy storage devices, wired communication for supporting auxiliary equipment, connector ports for receiving wired power, and other circuitry.

[0050] Display 14 can be used to present various content to a user's eyes. When viewed through eye-adaptive zone 13, the left and right displays 14 used to present a synthetic stereoscopic image to the user's eyes are sometimes collectively referred to as Display 14. For example, Display 14 can present virtual reality (VR) content. Virtual reality content can refer to content that includes only virtual objects in a virtual reality (computer-generated) environment. As another example, Display 14 can present mixed reality (MR) content. Mixed reality content can refer to content that includes both virtual objects and real objects from the real-world physical environment in which Device 10 is operating. As yet another example, Display 14 can present only real-world content. Real-world content can refer to content presented by one or more outward-facing cameras (see, for example...). Figure 1 The camera 46 in the image captures and transmits the image to the user as a real-time feed. Therefore, the real-world content captured by the front-facing camera is sometimes referred to as camera pass-through feed, (real-time) video pass-through feed, or pass-through video feed (stream).

[0051] According to some implementations, two optical modules in the head-mounted device 10 (such as the left optical module 40-1 and the right optical module 40-2) can be physically connected via the support structure 100 (see example...). Figure 3 ).like Figure 3 As shown, the support structure 100 may have a first distal end attached to the optical module 40-1 and a second distal end attached to the optical module 40-2. The support structure 100 joining the two optical modules 40 is sometimes referred to as an optical module (OM) support structure or bridging member. The support structure 100 may have one or more flexible portions and optionally one or more rigid or semi-rigid portions. A support structure 100 having at least a flexible or bendable portion is sometimes referred to as a flexible support structure 100.

[0052] Including through, for example Figure 3 The device 10, with optical modules 40-1 and 40-2 connected together by the flexible support structure 100 shown in the example, can be mounted on the user's head during normal operation. The yaw, roll, and pitch of the user's head, representing three degrees of freedom (DoF), collectively define the user's "head orientation." The user's head orientation, along with the user's position (which represents three additional degrees of freedom, e.g., X, Y, and Z in three-dimensional space), can be collectively defined herein as the user's "head pose." Therefore, the user's head pose represents six degrees of freedom (6DoF).

[0053] Since device 10 is mounted on the user's head during normal operation, references herein to head posture, head movement, head orientation, yaw of the user's head (e.g., rotation about a vertical axis), pitch of the user's head (e.g., rotation about a left-right axis), tumble of the user's head (e.g., rotation about a front-back axis), etc., can be considered interchangeable with references to device posture, device movement, device orientation, device yaw, device pitch, device tumble, etc. In some embodiments, device 10 (see...) Figure 1 Component 38 in the device may include a 6DoF tracking sensor that can be used to monitor both rotational movements (such as roll, pitch, and yaw) and translational movements in a 3D environment. Rotational movements (e.g., changes in device orientation) and translational movements (e.g., changes in device positioning or location) can be collectively defined as changes or transformations in posture.

[0054] Optical modules 40-1 and 40-2 are configured to display corresponding left and right images to the user's eyes, wherein when the user views the display, the left image from optical module 40-1 is fused with the right image from optical module 40-2. Proper fusion of the left and right images depends on proper physical alignment between the two optical modules 40-1 and 40-2. In some head-mounted devices, the left and right optical modules are attached or fixed to a rigid housing structure. In such devices, the physical alignment of the left and right optical modules is well controlled and can be calibrated a priori. In some head-mounted devices, such as in… Figure 3 In the device 10 of the type shown, optical modules 40-1 and 40-2 are connected together via a flexible support structure 100 and are therefore movable relative to each other during normal operation. When the device 10 is stationary and not mounted on the user's head, optical modules 40-1 and 40-2 may each have a default posture. During operation or when the device 10 is mounted on the user's head, the support structure 100 may twist, bend, flex, stretch, compress, warp, or otherwise deform in a manner that causes optical modules 40-1 and 40-2 to move relative to each other and thus deviate from their default postures. In doing so, optical module 40-1 may exhibit a first posture in 3D (XYZ) space, while optical module 40-2 may exhibit a second posture in 3D space. The posture of optical module 40 is sometimes referred to as the optical module posture and may be represented by six degrees of freedom (6DoF).

[0055] The difference between the first posture of optical module 40-1 and the second posture of optical module 40-2 may be referred to herein and defined as the “relative” posture between the pair of optical modules. The two modules may have a default relative posture, which represents any difference between the default posture of optical module 40-1 and the default posture of optical module 40-2. Any movement from the default posture of optical module 40-1 and / or optical module 40-2 may result in a deviation from the default relative posture. This deviation from the default relative posture, or this change from the default relative posture, is sometimes referred to as and defined as relative posture displacement. The relative posture displacement between optical modules 40-1 and 40-2 may include translational displacement (e.g., a relative change in the positioning or location of the two modules from the default posture) and / or rotational displacement (e.g., a relative change in the orientation of the two modules from the default posture).

[0056] For a head-mounted device 10 in which optical modules 40-1 and 40-2 may move relative to each other (e.g., when the flexible structure 100 bends or twists during normal operation), it may be desirable to measure the relative posture displacement between the two modules. Figure 4 An embodiment of a component for measuring the relative attitude displacement between a left optical module and a right optical module, which may be included within device 10, is shown. Figure 4 As shown, device 10 may include a transmitter component 110 disposed on or at optical module 40-1 and a detector component 112 disposed on or at optical module 40-2. The transmitter 110 may be a light emitter configured to output diffuse light 114. The transmitter 110 may output light 114 in the form of pulses (e.g., diffuse light pulses). The diffuse light 114 output from the transmitter 110 may travel toward the detector 112. A line of sight should exist between the transmitter 110 and the detector 112. Figure 4 The example is illustrative, in which transmitter 110 is disposed on first optical module 40-1 and detector 112 is disposed on second optical module 40-2. In other embodiments, transmitter 110 may be disposed on second optical module 40-2, and detector 112 may be disposed on first optical module 40-1.

[0057] Figure 5A This is a front view of an exemplary transmitter 110 according to some implementation schemes. For example... Figure 5AAs shown, emitter 110 may include three light-emitting components, such as light-emitting components 120-1, 120-2, and 120-3. Light-emitting components 120-1, 120-2, and 120-3 may be wide-emission light-emitting diodes (LEDs) or other types of LEDs configured to output diffuse light. Light-emitting components 120-1, 120-2, and 120-3 may be arranged along a circular path having a center 122 and a radius R. All light-emitting components 120 may emit light with the same wavelength or different wavelengths. As an example, light-emitting component 120-1 may be configured to emit light within a first wavelength range (e.g., component 120-1 may be a first LED configured to emit red light); light-emitting component 120-2 may be configured to emit light within a second wavelength range different from the first wavelength range (e.g., component 120-2 may be a second LED configured to emit green light); and light-emitting component 120-3 may be configured to emit light within a third wavelength range different from the first and second wavelength ranges (e.g., component 120-3 may be a third LED configured to emit blue light). If desired, component 120 may be configured to emit infrared (IR) light, ultraviolet (UV) light, or light with other suitable wavelengths.

[0058] Figure 5A The example is illustrative; in this example, emitter 110 includes three LEDs. Generally, emitter 110 may include two or more light-emitting elements 120, three to five light-emitting elements 120, five to ten light-emitting elements 120, or more than ten light-emitting elements 120. Multiple light-emitting elements 120 may be arranged along a circular path, triangular path, rectangular path, pentagonal path, hexagonal path, or octagonal path, or may be distributed in... Figure 5A The orientation shown indicates an LED array or any suitable pattern with uniform or non-uniform spacing on the YZ plane. Having more light-emitting components 120 on the YZ plane can be technically advantageous and beneficial for detecting the movement of the optical module in the YZ plane.

[0059] Figure 5B It is a combination Figure 5A A side view of the transmitter 110 of the described type. (See image.) Figure 5B As shown, the light-emitting component 120 can be disposed at different heights (depths) within the emitter. For example, light-emitting component 120-1 can be offset from light-emitting component 120-3 by a distance X1 in height (depth), while light-emitting component 120-2 can be offset from light-emitting component 120-3 by a distance X2 different from X1 in height (depth). For example, when optical modules 40-1 and 40-2 are in their nominal (undeflected) positions, these various heights in the X-axis direction can be achieved by tilting or rotating the emitter 110 about the Y and / or Z axes. Figure 5BThe example is illustrative, in which emitter 110 includes three LEDs at different depths. Generally, emitter 110 may include two or more light-emitting elements 120 disposed at different depths, three to five light-emitting elements 120 disposed at different depths, five to ten light-emitting elements 120 disposed at different depths, or more than ten light-emitting elements 120 disposed at different depths. Having more light-emitting elements 120 at different depths along the X (height) direction can be technically advantageous and beneficial for detecting the movement of the optical module in the X direction.

[0060] Figure 6 This is a side view of an exemplary detector 112 according to some implementation schemes. For example... Figure 6 As shown, detector 112 may include detector housing 130, sometimes referred to as module housing. An image sensor (such as image sensor 132) may be disposed at the base of housing 130. Image sensor 132 may include an imaging pixel array (e.g., hundreds or thousands of pixels). Image sensor 132 may be a color image sensor configured to output a color image or a monochrome image sensor configured to output a monochrome image. The device configuration where image sensor 132 is a color image sensor is sometimes described herein as an example. A mask structure (such as mask structure 134) may be disposed above image sensor 132. Mask structure 134 within detector 112 is sometimes referred to herein as a detector mask layer. Mask structure 134 may extend from one edge of housing 130 to the other edge of housing 130. Mask structure 134 may be configured as a top cover layer for detector 112. Mask structure 134 may be positioned at a distance (height) Hmask from sensor 132. The mask to sensor height Hmask may be configured or selected based on desired sensing requirements. Mask structure 134 may represent an opaque layer having multiple openings 136. Incoming light will be blocked by the opaque portions of mask structure 134, but can travel through the openings 136. The openings 136 may be air gaps, or may optionally be filled with a transparent material, such as glass, acrylic, polycarbonate, quartz, resin, or other transparent or translucent materials. Therefore, these transparent openings 136 are sometimes referred to herein as transparent (light-transmitting) windows or holes. Mask structure 134 configured in this manner is sometimes referred to as a patterned mask, a shadow mask, a perforated mask, or a mask. Figure 6The example is illustrative, in which detector 112 includes a single-layer mask structure 134. If desired, detector 112 may include two or more mask layers 134 stacked vertically relative to each other to help improve the accuracy of corresponding diffraction pattern detection at sensor 132, as illustrated by ellipsis 135. As an example, the two or more mask layers 134 may be parallel to each other. As another example, at least some of the two or more mask layers 134 may be angled or tilted relative to each other.

[0061] Figure 7 It is a combination Figure 6 A front view of an exemplary patterned mask structure 134 of the described type. (e.g.) Figure 7 As shown, the mask structure 134 may include an array of four by four openings 136. Each opening 136 may be a square or rectangular opening. This pattern of mask openings 136 in structure 134 is exemplary. Generally, the mask structure 134 may include a single opening 136, an array of two by two openings 136 (a total of four windows), an array of three by three openings 136 (a total of nine windows), or an array of four by four openings 136 (a total of 16 windows, such as...). Figure 7 (as shown in the example), an array of 5x5 openings 136 (25 windows in total), an array of 6x6 openings 136 (36 windows in total), fewer than 50 openings, fewer than 100 openings, or other regular or irregular patterns that may include openings arranged across the YZ plane. Figure 7 The example is also illustrative; in this example, each opening 136 is square. If desired, each opening 136 in the mask structure 134 can be circular, rectangular, hexagonal, octagonal, or may have other suitable shapes.

[0062] The working principle of transmitter 110 and detector 112 can be understood through Figure 8 and Figure 9 To give an example. Figure 8 It is an example of combination Figures 3 to 7 A side view illustrating how the transmitter 110 and detector 112 of the described type can be used to measure translational displacement in the YZ plane. For illustrative purposes, Figure 8 Only one exemplary light-emitting element 120 and one opening 136' in the mask structure 134 are shown, but the principles described below can be extended to emitters 110 with any number of light-emitting elements 120 and detectors 112 with any number of mask openings 136'. Figure 8As shown, when the light-emitting component 120 is positioned at the first (initial) location, it emits diffuse light 142, which produces a corresponding first diffraction pattern detected by the image sensor 132. This diffraction pattern, produced by illuminating the patterned mask structure 134 with diffuse light, is sometimes referred to as a mask pattern shadow, light pattern, edge pattern, or pattern. If the light source moves to a second (new) location in the direction of arrow 140, the same light-emitting component in the new location (see 120') emits diffuse light 142', which produces a corresponding second diffraction pattern (or mask pattern shadow) detected by the image sensor 132. This displacement in the detected diffraction pattern can be used to determine the corresponding amount of movement (translation) in the YZ plane. In other words, the relative translational displacement between the two optical modules in the YZ plane can be calculated by comparing the first diffraction pattern detected by sensor 132 with the second diffraction pattern.

[0063] Figure 9 It is an example of combination Figures 3 to 7 How can a transmitter 110 and detector 112 of the described type be used to measure depth displacement along the X direction in a side view? For illustrative purposes, Figure 9 Only one exemplary light-emitting element 120 and one opening 136' in the mask structure 134 are shown, but the principles described below can be extended to emitters 110 with any number of light-emitting elements 120 and detectors 112 with any number of mask openings 136'. Figure 9 As shown, when the light-emitting component 120 is positioned at the third location, it emits diffuse light 152, which produces a corresponding third diffraction pattern detected by the image sensor 132. If the light source moves in the direction of arrow 150 to a fourth location closer to the sensor 132, the same light-emitting component in the new location (see 120') will emit diffuse light 152', which produces a corresponding fourth diffraction pattern (or mask pattern shadow) detected by the image sensor 132. Here, the fourth diffraction pattern will be larger than the third diffraction pattern. This change in the size or scale of the detected diffraction pattern can be used to determine the corresponding amount of movement (translation) along the X-axis. In other words, the relative translational displacement between the two optical modules in the X-direction can be calculated by comparing the first diffraction pattern detected by the sensor 132 with the second diffraction pattern.

[0064] Figure 10 It is based on some implementation schemes for use in combination Figures 3 to 9A flowchart illustrating exemplary steps of using an emitter 110 and detector 112 of the described type to measure the relative attitude displacement between optical modules 40-1 and 40-2. During operation of block 160, emitter 110 can be configured to emit light, such as diffuse light. In one embodiment, all light-emitting elements 120 within emitter 110 can be simultaneously activated or pulsed. Alternatively, light-emitting elements 120 can be time-multiplexed. For example, in Figure 4 In the embodiment shown in Figure 5, which has three components 120-1, 120-2, and 120-3, component 120-1 may be activated during a first time period, followed by component 120-2 being activated during a second time period after the first time period, and then component 120-3 being activated during a third time period after the second time period, and so on (e.g., one LED may be selectively activated at a time to emit light pulses). As another example, components 120-1 and 120-2 may be activated concurrently during the first time period, followed by components 120-2 and 120-3 being activated concurrently during a second time period after the first time period, and then components 120-1 and 120-3 being activated concurrently during a third time period after the second time period, and so on (e.g., two LEDs may be selectively activated at a time to emit light pulses). Multiplexing different LEDs in this manner is optional.

[0065] As used herein, the term "concurrent" means at least partially overlapping in time. In other words, the first and second events are referred to herein as "concurrent" if at least some of the first events occur simultaneously with at least some of the second events (e.g., if at least some of the first events occur during, concurrently with, or when at least some of the second events occur). The first and second events can be concurrent if they are synchronized (e.g., if the entire duration of the first event overlaps with the entire duration of the second event in time), but they can also be concurrent if they are asynchronous (e.g., if the first event begins before or after the second event, ends before or after the second event, or if they do not partially overlap in time). As used herein, the term "at the time of" is synonymous with "concurrent."

[0066] During operation of block 162, detector 112 may be configured to sense corresponding images with different diffraction patterns. In some embodiments, detector 112 may be configured to acquire images periodically (e.g., by using image sensor 132 to capture at rates of more than 20 frames per second, more than 30 frames per second, more than 50 frames per second, more than 100 frames per second, less than 50 frames per second, less than 30 frames per second, less than 20 frames per second, less than 10 frames per second, less than 5 frames per second, or less than 2 frames per second, etc.). In some embodiments, detector 112 may be configured to acquire images in response to the detection of movement at either optical module 40. For example, one or more inertial measurement units (IMUs) or other motion sensors may be included within device 10 for detecting movement of optical modules 40-1 and 40-2. As optical modules 40-1 and 40-2 move relative to each other, images with different diffraction patterns may be sensed by detector 112.

[0067] During operation of frame 164, device 10 can be configured to calculate the relative attitude displacement between optical modules 40-1 and 40-2 by triangulation of various diffraction patterns sensed during frame 162 (e.g., based on at least three edges in 3D space). The 6DoF relative attitude displacement between optical modules 40-1 and 40-2 can be calculated by observing the translation and scaling of the diffraction patterns during time multiplexing of activation of the light-emitting element 120 within emitter 110. Such processing and triangulation of the diffraction patterns can be performed at control circuitry 20 of device 10 (see [link to device 10]). Figure 2 If needed, the control circuit 20 may optionally employ a trained model to analyze the detected diffraction pattern. As an example, the trained model may implement a feature-based technique that detects corners, edges, and / or other geometrically located features of the diffraction pattern.

[0068] As another example, the trained model can implement an intensity-based technique that compares light intensity on a per-pixel basis to match the entire image pattern, rather than relying on certain geometric features (e.g., corners). This intensity-based method may include comparing a detected diffraction pattern with a simulated diffraction pattern to identify relative pose displacements that minimize the difference between the two patterns. The simulated diffraction pattern may be controlled by control circuitry 20 (see...). Figure 1The diffraction pattern can be rendered based on the estimated relative pose displacement between modules 40-1 and 40-2, or by other processing elements in detector 112. Alternatively, a set of pre-simulated diffraction patterns corresponding to different relative pose displacements can be stored on device 10. The trained model can also take into account additional system constraints, such as certain physical constraints preventing the optical modules from moving in a certain way. In other words, the model can be configured to receive light intensity information and physical constraints associated with the movement of optical modules 40-1 and 40-2 within device 10 as input. Using such a model can be technically advantageous compared to geometric triangulation and is beneficial for providing an improved signal-to-noise ratio (SNR) for the overall determination of the relative pose displacement. If desired, the control circuit 20 can also take into account emission characteristics at emitter 110, such as the emission current at the source, in addition to considering only the diffraction pattern sensed by detector 112, to further improve the SNR. In general, a control diffraction pattern corresponding to the default relative pose of optical modules 40-1 and 40-2 can be a priori calibrated. Then, the deviation from the diffraction pattern can be analyzed to calculate the offset from the default relative pose, thereby determining the relative pose displacement based on the default relative pose.

[0069] Figure 10 The operations described are illustrative. In some embodiments, one or more of the described operations may be modified, replaced, or omitted. In some embodiments, one or more of the described operations may be performed in parallel. In some embodiments, additional processes may be added or inserted between the described operations. If necessary, the order of certain operations may be reversed or changed, and / or the timing of the described operations may be adjusted so that they occur at slightly different times. In some embodiments, the described operations may be distributed across a larger system.

[0070] Figure 4 The example is illustrative, in which transmitter 110 is located at optical module 40-1 and detector 112 is located at optical module 40-2. Figure 11 Another embodiment of the device 10 is shown, wherein both the transmitter 110 and the detector 112 are disposed at the optical module 40-1. Figure 11 As shown, emitter 110 can be configured to emit diffuse light 114 toward optical module 40-2. The diffuse light 114 can be reflected from a layer (such as layer 116) on optical module 40-2 and travel back toward detector 112 (see reflected light 118). Layer 116 can be a reflective layer or other thin-film interference layer. If desired, layer 116 can be omitted entirely, and emitted light 114 can simply bounce off a flat surface of optical module 40-2 and propagate back toward detector 112. If emitter 110 is configured to emit relatively high-power light, such a surface of optical module 40-2 does not need to be reflective. Figure 11 The structure of the transmitter 110 in the middle is similar to that of the already combined Figure 5A and Figure 5B The structure described. Figure 11 The structure of detector 112 in the middle is similar to that of already combined Figure 6 and Figure 7 The structure described. Figure 11 The operation can also be used to operate Figure 11 The device 10 calculates the relative posture displacement between optical modules 40-1 and 40-2 with improved SNR, and does not require repetition to avoid blurring this embodiment.

[0071] The above text, combined with Figure 5 to... Figure 11 The described implementation is exemplary, in which only detector 112 has a mask structure. According to other implementations, transmitter 110 may optionally include a separate mask structure (see, for example...). Figure 12 ). Figure 12 This is a side view of an exemplary emitter 110 with its own mask structure. (See example...) Figure 12 As shown, emitter 110 may include emitter housing 170, sometimes referred to as module housing. A light source (such as light source 172) may be disposed at the base of housing 170. Light source 172 may be a display panel (e.g., a light source having a display pixel array), a light panel (e.g., a non-pixelated light source), a light source configured to output diffuse light, a light source configured to output coherent light, a laser source, or other types of light source. In the example where light source 172 is a pixelated display panel, portions or regions of the display pixel array may be selectively activated and deactivated at different times to simulate a time-multiplexed emission scheme, if desired.

[0072] A mask structure (such as mask structure 174) may be disposed above the light source 172. The mask structure 174 within the emitter 110 is sometimes referred to herein as an emitter mask layer. The emitter mask structure 174 may extend from one edge of the housing 170 to the other edge of the housing 170. The mask structure 174 may be configured as a top cover layer for the emitter 110. The mask structure 174 may be set at a distance (height) Hmask' from the light source 172. This mask to the source height Hmask' may be configured or selected based on desired emission requirements. The mask structure 174 may represent an opaque layer having a plurality of openings 176. A portion of the light emitted from the light source 172 will be blocked by the opaque portion of the mask structure 174, while the remainder of the emitted light may travel through the openings 176 and toward the detector 112 (see [link to relevant documentation]). Figure 4The opening 176 may be an air gap, or it may optionally be filled with a transparent material, such as glass, acrylic, polycarbonate, quartz, resin, or other transparent or translucent materials. Therefore, these transparent openings 176 are sometimes referred to herein as transparent (light-transmitting) windows or holes.

[0073] Figure 12 The example is illustrative; in this example, emitter 110 includes a single-layer mask structure 174. If desired, emitter 110 may include two or more mask layers 174 stacked vertically relative to each other to help constrain the emission pattern of light source 172, as illustrated by ellipses 175. As an example, two or more mask layers 174 may be parallel to each other. As another example, at least some of the two or more mask layers 174 may be angled or tilted relative to each other. Generally, the pattern of emitter mask layer 174 should match or be identical to the pattern of detector mask layer 134. As an example, if detector mask layer 134 has a pattern such as... Figure 7 The transmitter mask layer 174 should also be a matching mask with an array of 4×4 openings, as shown in the diagram. In other embodiments, the detector mask layer 134 may optionally be mismatched with the transmitter mask layer 174 (e.g., mask structures 134 and 174 may have different aperture patterns).

[0074] Generally speaking, mask structures 134 and 174 can have any suitable pattern. Figures 13A to 13E These are front views of exemplary mask structures 134 and 174 with a single opening. Figure 13A This is a front view of the emitter mask structure 174, where the shaded area 180 represents the constrained pattern of emitted light passing through the mask structure 174. Figure 13B This is a front view of the corresponding matching detector mask structure 134 inside the detector. Figure 13C An example is illustrated where a translational (lateral) displacement exists in the Z direction. This translational displacement can be detected by sensing a pattern in the shadow region 180-1, which represents the pattern of emitted light output from the masked emitter and ultimately reaching the image sensor with the masked detector (e.g., the sensed light pattern 180-1 will pass through both mask structures 134 and 174). This provides sensitivity for relative displacement measurement in the X direction.

[0075] Figure 13D A second scenario is illustrated, in which there is a translational (lateral) displacement in the Y direction. This translational displacement can be detected by sensing a pattern in the shadow region 180-2, which represents the pattern of emitted light output from the masked emitter and ultimately reaching the image sensor with the masked detector (e.g., the sensed light pattern 180-2 will pass through both mask structures 134 and 174). This provides sensitivity for relative displacement measurement in the Y direction. Figure 13E A third case is illustrated, in which rotational displacement about the X-axis exists. This rotational displacement can be detected by sensing a pattern in the shadow region 180-3, which represents the pattern of emitted light output from the masked emitter and ultimately reaching the image sensor with the masked detector (e.g., the sensed light pattern 180-3 will pass through both mask structures 134 and 174). This provides sensitivity for relative displacement measurement about the X-axis. Thus, the use of mask structures 134 and 174, each with only one opening, provides the detection of up to three degrees of freedom (e.g., relative translational displacement in the Z direction, relative translational displacement in the Y direction, and relative rotational displacement about the X-axis).

[0076] Figures 14A to 14G These are front views of exemplary mask structures 134 and 174 having an array of openings (e.g., an array of 2×2 openings or windows). Figure 14A This is a front view of the emitter mask structure 174, where the shaded area 182 represents the constrained pattern of emitted light passing through the mask structure 174. Figure 14B This is a front view of the corresponding matching detector mask structure 134 inside the detector. Figure 14C An example is illustrated where a translational (lateral) displacement exists in the Z direction. This translational displacement can be detected by sensing a pattern in the shadow region 182-1, which represents the pattern of emitted light output from the masked emitter and ultimately reaching the image sensor with the masked detector (e.g., the sensed light pattern 182-1 will pass through both mask structures 134 and 174). This provides sensitivity for relative displacement measurement in the X direction. Figure 14D A second scenario is illustrated, in which there is a translational (lateral) displacement in the Y direction. This translational displacement can be detected by sensing a pattern in the shadow region 182-2, which represents the pattern of emitted light output from the masked emitter and ultimately reaching the image sensor with the masked detector (e.g., the sensed light pattern 182-2 will pass through both mask structures 134 and 174). This provides sensitivity for relative displacement measurement in the Y direction.

[0077] Figure 14E A third case is illustrated where rotational displacement about the Y-axis exists. This rotational displacement can be detected by sensing a pattern in the shadowed region 182-3, which represents the pattern of emitted light output from the masked emitter and ultimately reaching the image sensor with the masked detector (e.g., the sensed light pattern 182-3 will pass through both mask structures 134 and 174). This provides sensitivity for relative displacement measurement about the Y-axis. Figure 14FA fourth case is illustrated, in which rotational displacement about the Z-axis exists. This rotational displacement can be detected by sensing a pattern in the shaded region 182-4, which represents the pattern of emitted light output from the masked emitter and ultimately reaching the image sensor with the masked detector (e.g., the sensed light pattern 182-4 will pass through both mask structures 134 and 174). This provides sensitivity for relative displacement measurement about the Z-axis.

[0078] Figure 14G A fifth case is illustrated, in which rotational displacement about the X-axis exists. This rotational displacement can be detected by sensing a pattern in the shadowed regions 182-5, which represents the pattern of emitted light output from the masked emitter and ultimately reaching the image sensor with the masked detector (e.g., the sensed light pattern 182-5 will pass through both mask structures 134 and 174). This provides sensitivity for relative displacement measurement about the X-axis. Thus, using mask structures 134 and 174, each with an array of 2×2 openings, detection of up to five degrees of freedom (e.g., relative translational displacement in the Z direction, relative translational displacement in the Y direction, relative rotational displacement about the Y-axis, relative rotational displacement about the Z-axis, and relative rotational displacement about the X-axis) can be provided.

[0079] The example in Figure 14 is illustrative, in which mask structures 134 and 174 each have an array of 2×2 openings. Generally, having more openings provides greater detection resolution (e.g., to provide increased accuracy when measuring displacement in any particular direction), which helps reduce the impact of mask manufacturing defects or image capture errors. Generally, mask structures 134 and 174 may each be a mask layer having more than four openings, more than ten openings, more than 25 openings, more than 50 openings, more than 100 openings, more than 500 openings, or more than 1000 openings.

[0080] The example described above is illustrative, in which the head-mounted device 10 includes only a single transmitter-detector pair (e.g., a transmitter 110 located at one optical module and a detector 112 located at another optical module). Figure 15 Another embodiment in which the head-mounted device 10 includes multiple transmitter-detector pairs is illustrated. Using multiple transmitter-detector pairs allows the system to measure more information, which allows the control circuitry to generate more accurate relative posture displacements. For example... Figure 15 As shown, the first transmitter 110-1 and the second transmitter 110-2 can be disposed on the optical module 40-1, while the first detector 112-1 and the second detector 112-2 are disposed on the optical module 40-2. The transmitters 110-1 and 110-2 can be combined. Figures 12 to 14. A masked emitter of the type described. Emitter 110-1 may be configured to emit light toward detector 112-1 (see, for example, path 114-1) and may be associated together with a first metering type. Emitter 110-2 may be configured to emit light toward detector 112-2 (see, for example, path 114-2) and may be associated together with a second metering type different from the first metering type. Emitters 110-1 and 110-2 may be emitters of different types. Detectors 112-1 and 112-2 may be detectors of different types.

[0081] Figure 15 The example is illustrative, in which the transmitter and detector are located in different optical modules. If desired, some metrology types may involve juxtaposing the transmitter and detector in a single optical module, such as... Figure 11 As shown in the example. This type of metrology may include optical detection and ranging (LiDAR) sensors or depth sensors. For example, a depth sensor located at module 40-1 or 40-2 can be used to obtain a depth value by sensing the distance between modules 40-1 and 40-2. The relative posture displacement determined by the control circuitry can also be calculated based on such depth values ​​or distance information. Using multiple optical sensors of different metrology types in device 10 can be technically advantageous and beneficial for further providing detection sensitivity in all six degrees of freedom (e.g., translational displacement in the X, Y, and Z directions, and rotational displacement about the X, Y, and Z axes). Still referring to Figure 15 The additional detector 112-3 can optionally be positioned at an angle relative to the transmitter 110-2, as illustrated in the optical path 114-3. In other words, the transmitter 110-2 can be configured to output light toward both detectors 112-2 and 112-3. Using the transmitter 110-2 in combination with two detectors 112-2 and 112-3 (each detector positioned with a different alignment or angle relative to the transmitter 110-2) also allows the system to achieve attitude displacement detection sensitivity in all six degrees of freedom.

[0082] Figure 16 Another suitable embodiment of the device 10 with multiple transmitter-detector pairs is shown. For example... Figure 16 As shown, the first transmitter 110-1 and the second detector 112-2 can be disposed on the optical module 40-1, while the first detector 112-1 and the second transmitter 110-2 are disposed on the optical module 40-2. The transmitters 110-1 and 110-2 can be combined. Figures 12 to 14. A masked emitter of the type described. Emitter 110-1 may be configured to emit light toward detector 112-1 (see, for example, path 114-1) and may be associated with a first metering type. Emitter 110-2 may be configured to emit light toward detector 112-2 (see, for example, path 114-2) and may be associated with a second metering type different from the first metering type. Figure 16 In the example, detector 112 is a larger component than transmitter 110, so pairing the smaller transmitter 110-1 with the larger detector 112-2 can help alleviate spatial constraints at optical module 40-1. Similarly, at the other end, pairing the smaller transmitter 110-2 with the larger detector 112-1 can help alleviate spatial constraints at optical module 40-2. Furthermore, using multiple different metrology types of optical sensors in device 10 can be technically advantageous and beneficial for further providing detection sensitivity across all six degrees of freedom (e.g., translational displacement in the X, Y, and Z directions, and rotational displacement about the X, Y, and Z axes). If desired, device 10 may include three or more metrology types for measuring the relative posture displacement between optical modules 40-1 and 40-2.

[0083] The optical modules 40-1 and 40-2 of the head-mounted device 10 are used to measure the relative posture displacement. Figures 4 to 16 The implementation plan is illustrative. Figure 17 Another embodiment for measuring the relative posture displacement between optical modules 40-1 and 40-2 within a head-mounted device 10 is shown. Figure 17 As shown, a light source (such as light source 200) may be disposed on or at optical module 40-1, a first reflector component (such as half-reflector 208) may be disposed on or at optical module 40-2, a beam splitter (such as beam splitter 204) may be disposed between light source 200 and half-reflector 208, a second reflector component (such as reflector 206) may be disposed on a first side of beam splitter 204, a first detector (such as detector 202) may be disposed on a second side (opposite to the first side) of beam splitter 204, and a second detector (such as detector 210) may be disposed on or at optical module 40-2. Light source 200 may be configured to output a coherent beam, such as a laser beam. A “coherent” beam can refer to a beam in which the waves have a constant phase relationship and a single wavelength or a narrow wavelength range (e.g., light waves are synchronized with each other and maintain a fixed phase difference in time and space). Therefore, light source 200 is sometimes referred to as a laser source. As an example, laser source 200 may be a vertical cavity surface-emitting laser (VCSEL). The term “half” reflector may refer to, and is defined herein as, a partially reflective mirror structure that reflects a first portion of incident light while transmitting a second portion of incident light.

[0084] Figure 17 These light-emitting and various detector components operate based on the principle of optical interference, in which two coherent beams interact to produce constructive and destructive interference patterns. Figure 20 It shows the operation of at least Figure 17 A flowchart illustrating the exemplary steps of the various light-emitting and sensing components shown. During operation of block 250, the light source 200 can be configured to emit a beam 212 toward the beam splitter 204. For example, the VCSEL 200 can emit one or more laser pulses toward the beam splitter 204. The beam splitter 204 can refer to an optical component that splits a beam into two or more individual beams, such as by reflecting a portion of the incoming light while transmitting the remainder. Various types of beam splitters 204 can be employed. The beam splitter 204 can receive the beam 212 output from the light source 200 and output a first beam 212-1 toward the reflector 206 and a second beam 212-2 toward the semi-reflector 208.

[0085] During operation of frame 252, the first beam 212-1 is reflected (bounced) from mirror 206 and propagates back towards beam splitter 204 as reflected light 214. Simultaneously, a first portion of the second beam 212-2 is reflected (bounced) from half-mirror 208 and propagates back towards beam splitter as reflected light 216. Reflected light 214 and reflected light 216 may meet and interfere with each other (e.g., constructive and destructive interference based on the superposition of the electromagnetic waves of the two beams) to produce a superimposed beam 218. The superimposed beam 218 can then be sensed by detector 202. Detector 202 may be a two-dimensional (2D) image sensor with hundreds or thousands of image pixels. The superimposed beam 218 can generate a corresponding interference pattern based on the phase (offset) difference between beams 214 and 216. Figure 17 The light propagating between optical modules 40-1 and 40-2 (such as beams 212, 212-2, and 216) can be transmitted via light guides, light waveguides, waveguides, or other optical tunnels / channels, as shown by the dashed path 230. The interference pattern generated by the superimposed beam 218 can be sensed by detector 202.

[0086] During the operation of block 254, the associated control circuitry (such as...) Figure 2The control circuit 20) can analyze the interference pattern to determine the relative translational (XYZ) displacement in 3D space. In other words, the relative translational displacement between the two optical modules in the XYZ direction can be calculated by comparing the interference pattern sensed by detector 202 with a default interference pattern associated with the default relative orientation. Generally, the default interference pattern corresponding to the default relative orientation of optical modules 40-1 and 40-2 can be a priori calibrated. Then, the deviation from the default interference pattern can be analyzed to calculate the offset from the default relative orientation, thereby determining the relative orientation (translational) displacement based on the default relative orientation.

[0087] The operation of block 254 can be used to determine the relative movement or displacement between optical modules 40-1 and 40-2 in XYZ space. Additionally, during the operation of block 256, information from the two detectors 202 and 210 can be compared to determine the relative rotational (angular) displacement between modules 40-1 and 40-2. As described above, detector 202 can receive superimposed light 218, which, in addition to the interference pattern, can also generate a first beam (light) spot sensed by detector 202. The first beam (laser) spot generated by light 218 can have different sizes and / or can fall at different locations on the image sensor of detector 202, depending on the relative rotational displacement between the two optical modules 40-1 and 40-2. Furthermore, a portion of the beam 212-2 propagating toward the semi-reflective mirror 208 can be transmitted through the semi-reflective mirror 208 and sensed by the second detector 210. Detector 210 can be a two-dimensional (2D) image sensor with hundreds or thousands of image pixels. Detector 210 can receive the portion of light 212-2 transmitted through the semi-reflective mirror 208, which generates a second beam (light) spot sensed by detector 210. The second beam (laser) spot generated by the light transmitted through the semi-reflective mirror 208 can have different sizes and / or fall at different positions on the image sensor of detector 210, depending on the relative rotational displacement between the two optical modules 40-1 and 40-2. In other words, control circuit 20 can compare the positioning and / or size of the first beam spot sensed by detector 202 with the positioning and / or size of the second beam spot sensed by detector 210 to determine the relative angular rotational (Rx, Ry, Rz) displacement between the two optical modules 40-1 and 40-2.

[0088] Although the operation of box 256 is shown as occurring after the operation of box 254, the operation of box 256 may occur before or concurrently with the operation of box 254. By combining the interference pattern information collected from box 254 and the beam spot information collected from box 256, the control circuit 20 can calculate submicron level translation and angular deviations (e.g., relative attitude displacements) between the two optical modules 40-1 and 40-2.

[0089] Generally, the light source 200 can be configured to emit one or more laser pulses of different wavelengths. As an example, the light source 200 can output a single-wavelength laser pulse. As another example, the light source 200 can be configured to output two lasers with different wavelengths. By employing two coherent laser sources, the system can sense two interference patterns corresponding to two different wavelengths. The phase (offset) difference at each wavelength will be proportional to the difference in optical path length, but the effective wavelength of the system becomes a composite wavelength determined by the beat frequency between the two wavelengths. This composite wavelength is much longer than either of the individual wavelengths. Therefore, by comparing the phase measurements from the two different wavelengths, the system can uniquely solve for displacements exceeding a single wavelength, thus significantly extending the measurement range. This multi-wavelength approach can be technically advantageous and beneficial for achieving high-resolution measurements over large displacements while maintaining sensitivity to sub-micron translational and rotational displacements. Furthermore, the light source 200 can be optionally polarized (e.g., linearly polarized) to further generate rotational information for the beam.

[0090] Figure 20 The operations described are illustrative. In some embodiments, one or more of the described operations may be modified, replaced, or omitted. In some embodiments, one or more of the described operations may be performed in parallel. In some embodiments, additional processes may be added or inserted between the described operations. If necessary, the order of certain operations may be reversed or changed, and / or the timing of the described operations may be adjusted so that they occur at slightly different times. In some embodiments, the described operations may be distributed across a larger system.

[0091] Figure 17 The implementation is exemplary, in which the beam splitter 204, detector 202, and reflector 206 are positioned somewhere between optical modules 40-1 and 40-2. If desired, the beam splitter 204, detector 202, and reflector 206 may be positioned at the midpoint or other intermediate location between modules 40-1 and 40-2. Figure 18 Another embodiment of the device 10 in which the beam splitter 204, detector 202, and reflector 206 are disposed at or on the optical module 40-1 (e.g., near the light source 200) is illustrated. Here, the laser source 200, beam splitter 204, detector 202, and reflector 206 are all juxtaposed at the optical module 40-1. This arrangement operates similarly to a previously combined... Figure 17 The working principle described, and therefore applicable. Figure 20 Similar operational steps are shown, but these steps need not be repeated to avoid obscuring this implementation scheme.

[0092] Alternatively, Figure 19 Another embodiment of the device 10, in which the beam splitter 204, detector 202, and reflector 206 are disposed at or on the optical module 40-2 (e.g., near detector 210), is illustrated. Here, the beam splitter 204, detector 202, reflector 206, half-reflector 208, and detector 210 are all juxtaposed at the optical module 40-2. This arrangement operates similarly to a previously combined... Figure 17 The working principle described, and therefore applicable. Figure 20 Similar operational steps are shown, but these steps need not be repeated to avoid obscuring this implementation scheme.

[0093] According to and combined Figures 4 to 20 Another implementation scheme described is not mutually exclusive. Figure 21 The diagram illustrates how the head-mounted device 10 may also include multiple angle detectors 304 disposed on a rigid structure, such as the rigid support structure 300 of the device 10. The rigid structure 300 may include a first portion extending through optical module 40-1 and a second portion extending through optical module 40-2. Figure 21 As shown, a first angle detector 304-1 may be attached to a first position on a first portion of the rigid support structure 300, while a second angle detector 304-2 may be attached to a second position on a second portion of the rigid support structure 300. A first light source (such as light source 302-1) may be disposed on or at the optical module 40-1, while a second light source (such as light source 302-2) may be disposed on or at the optical module 40-2. Each light source 302 may be configured to output a coherent beam, such as a laser beam. Therefore, light sources 302-1 and 302-2 are sometimes referred to as laser sources. As an example, laser source 302 may be a vertical cavity surface-emitting laser (VCSEL). Optical modules 40-1 and 40-2 are not fixed to the rigid support structure 300 and may move relative to each other as the flexible support structure 100 bends or twists.

[0094] Figure 22 yes Figure 21 A side view of an exemplary angle detector 304 of the type shown. (See diagram) Figure 22 As shown, the angle detector 304 may include an image sensor 310 and one or more grating structures 312 disposed above the image sensor 310. The image sensor 310 may include an imaging pixel array (e.g., hundreds or thousands of pixels). Incoming light 306 may propagate through the grating layer 312 and be sensed by the image sensor 310. Figure 23 This is a front view of an exemplary grating structure 312 that can be included as part of the angle detector 304. (Example) Figure 23As shown, the grating structure 312 may have one or more first portions having a grating parallel to the Y direction, and one or more second portions having a grating parallel to the X direction. This grating arrangement is merely exemplary. Generally, the grating structure 312 may be divided into any number of portions, each of which may have a grating extending along the same or different directions. This type of detector 304 is sometimes referred to as a Talbot sensor or other types of optical sensors operable to sense the angle of incidence of light.

[0095] During normal operation, light source 302-1 emits a first coherent (laser) beam 306-1 toward a first angle detector 304-1, while light source 302-2 emits a second coherent (laser) beam 306-2 toward a second angle detector 304-2. Beams 306-1 and 306-2 may optionally be polarized (e.g., using a linear polarizer at the output of VCSEL 302). Operating in this manner, detector 304-1 receives beam 306-1 from light source 302-1, which generates a first beam (light) spot sensed by detector 304-1. The first beam (laser) spot generated by light 306-1 may have different sizes and / or may fall at different locations on the image sensor of detector 304-1, depending on the relative rotational displacement between optical module 40-1 and rigid structure 300. At the other end, detector 304-2 can receive beam 306-2 from light source 302-2, which can generate a second beam (light) spot sensed by detector 304-2. The second beam (laser) spot generated by light 306-2 can have different sizes and / or can fall at different positions on the image sensor of detector 304-2, depending on the relative rotational displacement between optical module 40-2 and rigid structure 300. In other words, control circuit 20 can compare the positioning and / or size of the first beam spot sensed by detector 304-1 with the positioning and / or size of the second beam spot sensed by detector 304-2 to determine the relative angular rotational (Rx, Ry, Rz) displacement between the two optical modules 40-1 and 40-2.

[0096] Figure 21The example is illustrative, in which two angle detectors 304 are mounted along a single plane (facing the same direction) of the rigid support structure 300 of device 10, or mounted on a common straight edge of the rigid support structure. In other embodiments, the two angle detectors 304-1 and 304-2 may be mounted on different surfaces, edges, or portions of the rigid support structure of device 10. Generally, such a rigid support structure does not need to be straight, but can have any physical shape. In such scenarios, light sources 302-1 and 302-2 may point in different directions. Generally, the default spot position and / or size of the sensing beam corresponding to the default relative posture of optical modules 40-1 and 40-2 can be calibrated a priori. The control circuit 20 can then analyze the deviation from the default spot position and / or size to calculate the offset from the default relative posture, thereby determining the relative posture (e.g., rotational) displacement based on the default relative posture.

[0097] The above text combined Figures 1 to 23 The described methods and operations can be performed by components of device 10 using software, firmware, and / or hardware (e.g., dedicated circuitry or hardware). Software code for performing these operations may be stored on a non-transitory computer-readable storage medium (e.g., a tangible computer-readable storage medium) stored on one or more components of device 10 (e.g., ...). Figure 1 The software code may be referred to as software, data, instructions, program instructions, or code. Non-transitory computer-readable storage media may include drives, non-volatile memory (such as non-volatile random access memory (NVRAM)), removable flash drives or other removable media, other types of random access memory, etc. The software stored on the non-transitory computer-readable storage medium may be executed by processing circuitry (e.g., one or more processors in control circuitry 20) on one or more components of device 10. The processing circuitry may include a microprocessor, application processor, digital signal processor, central processing unit (CPU), application-specific integrated circuit (ASIC) with processing circuitry, or other processing circuitry.

[0098] There are many different types of electronic systems that enable people to sense and / or interact with a variety of XR environments. Examples include head-mounted systems, projection-based systems, head-up displays (HUDs), vehicle windshields with integrated display capabilities, windows with integrated display capabilities, displays shaped as lenses designed to be placed on a person's eyes (e.g., similar to contact lenses), headsets / earphones, speaker arrays, input systems (e.g., wearable or handheld controllers with or without haptic feedback), smartphones, tablets, and desktop / laptop computers.

[0099] To help protect user privacy, best practices can be used to handle any personal user information collected by device 10. These best practices include meeting or exceeding any applicable privacy rules. Option-join and option-opt-out options and / or other options can be provided that allow users to control the use of their personal data.

[0100] According to one embodiment, a head-mounted device includes: a first optical module configured to output content to a first eye-adaptive region; a second optical module configured to output content to a second eye-adaptive region; a support structure attaching the first optical module to the second optical module, wherein the support structure at least partially includes a flexible portion that allows the first and second optical modules to move relative to each other when flexed; an emitter disposed on the first optical module and configured to emit light; a detector including a patterned mask having a plurality of openings and an image sensor configured to receive light propagation through at least a portion of the plurality of openings in the patterned mask to sense one or more corresponding diffraction patterns; and control circuitry configured to analyze the one or more diffraction patterns sensed by the image sensor of the detector to determine a relative kinetic displacement between the first and second optical modules.

[0101] According to another embodiment, the transmitter may optionally include: a first light-emitting component configured to emit light in a first wavelength range; a second light-emitting component configured to emit light in a second wavelength range different from the first wavelength range; and a third light-emitting component configured to emit light in a third wavelength range different from the first and second wavelength ranges.

[0102] According to another embodiment, the first light-emitting component is optionally disposed at a first depth within the emitter; the second light-emitting component is optionally disposed at a second depth within the emitter, which is different from the first depth; and the third light-emitting component is optionally disposed at a third depth within the emitter, which is different from the first and second depths.

[0103] According to another embodiment, the first light-emitting component is optionally selectively activated during a first time period, the second light-emitting component is optionally selectively activated during a second time period after the first time period, and the third light-emitting component is optionally selectively activated during a third time period after the second time period.

[0104] According to another embodiment, the first light-emitting component and the second light-emitting component are optionally activated concurrently during a first time period, the second light-emitting component and the third light-emitting component are optionally activated concurrently during a second time period after the first time period, and the first light-emitting component and the third light-emitting component are optionally activated concurrently during a third time period after the second time period.

[0105] According to another embodiment, the detector may optionally include an additional patterned mask stacked on top of the patterned mask.

[0106] According to another embodiment, the control circuit is optionally configured to determine the relative attitude displacement between the first optical module and the second optical module based on a model configured to analyze one or more of the following: the geometric features of the one or more diffraction patterns, the light intensity information of the one or more diffraction patterns, and the physical constraints associated with the movement of the first optical module and the second optical module.

[0107] According to another embodiment, the detector may optionally be mounted on the second optical module.

[0108] According to another embodiment, the detector is optionally disposed on the first optical module, and the reflective layer disposed on the second optical module is optionally configured to reflect light emitted from the transmitter back to the detector.

[0109] According to another embodiment, the transmitter may optionally include: an additional patterned mask having a plurality of openings; and a light source configured to output light propagating through the plurality of openings in the additional patterned mask.

[0110] According to another embodiment, the head-mounted device may optionally further include a depth sensor disposed at a first optical module or a second optical module, wherein the depth sensor is configured to output a depth value based on the distance between the first optical module and the second optical module, and wherein control circuitry is further configured to analyze the depth value to determine the relative posture displacement between the first optical module and the second optical module.

[0111] According to another embodiment, the head-mounted device may optionally further include: an additional transmitter disposed at the second optical module; and an additional detector disposed at the first optical module, wherein the additional transmitter is configured to emit light toward the additional detector, and wherein control circuitry is configured to analyze information measured by the additional detector to determine the relative posture displacement between the first optical module and the second optical module.

[0112] According to another embodiment, the head-mounted device may optionally include an additional detector disposed at the second optical module and configured to receive light from the transmitter, wherein the control circuitry is further configured to analyze the information measured by the additional detector to determine the relative posture displacement between the first and second optical modules.

[0113] According to one embodiment, a head-mounted device includes: a first optical module configured to output content to a first eye-adaptive region; a second optical module configured to output content to a second eye-adaptive region; a support structure attaching the first optical module to the second optical module, wherein the support structure at least partially includes a flexible portion that allows the first and second optical modules to move relative to each other when flexed; a light source disposed on the first optical module and configured to output a coherent beam; a beam splitter configured to split the coherent beam into a first beam and a second beam; a reflector configured to reflect the first beam; a semi-reflector disposed on the second optical module and configured to reflect a portion of the second beam; a first detector configured to sense an interference pattern generated by a phase offset difference between the first beam reflected from the reflector and the portion of the second beam reflected from the semi-reflector; and control circuitry configured to analyze the interference pattern sensed by the first detector to determine a relative translational displacement between the first and second optical modules.

[0114] According to another embodiment, the head-mounted device may optionally also include a second detector configured to sense the transmission of the second beam through a portion of the semi-reflective mirror.

[0115] According to another embodiment, a first detector is optionally configured to sense a first beam spot associated with a superimposed beam, the superimposed beam including a portion of a first beam reflected back from a reflector and a portion of a second beam reflected back from a semi-reflector; a second detector is optionally configured to sense a second beam spot associated with the portion of the second beam transmitted through the semi-reflector; and a control circuit is optionally configured to analyze the position of the first beam spot in the first detector and the position of the second beam spot in the second detector to determine a relative rotational displacement between the first optical module and the second optical module.

[0116] According to another embodiment, the coherent beam and the first beam may optionally propagate between the first optical module and the second optical module via a light guide, light guide, light pipe or waveguide between the first optical module and the second optical module.

[0117] According to another embodiment, the beam splitter, the reflector, and the first detector may optionally be located at an intermediate position between the first optical module and the second optical module.

[0118] According to another embodiment, the beam splitter, the reflector, and the first detector may optionally be disposed at or on the second optical module.

[0119] According to another embodiment, the beam splitter, the reflector, and the first detector may optionally be disposed at or on the first optical module.

[0120] According to one embodiment, a head-mounted device includes: a first optical module configured to output content to a first eye-adaptive region; a second optical module configured to output content to a second eye-adaptive region; a support structure attaching the first optical module to the second optical module, wherein the support structure at least partially includes a flexible portion that allows the first and second optical modules to move relative to each other when flexed; a rigid structure extending between the first and second optical modules; a first angle detector disposed at a first location on the rigid structure; a second angle detector disposed at a second location on the rigid structure; a first light source disposed on the first optical module and configured to output a first coherent light beam toward the first angle detector; a second light source disposed on the second optical module and configured to output a second coherent light beam toward the second angle detector; and control circuitry configured to analyze the position of the first light beam spot sensed by the first angle detector and the position of the second light beam spot sensed by the second angle detector to determine a relative rotational displacement between the first and second optical modules.

[0121] According to another embodiment, the first angle detector may optionally include a first image sensor and one or more grating structures disposed above the first image sensor, and the second angle detector may optionally include a second image sensor and one or more grating structures disposed above the second image sensor.

[0122] According to another embodiment, the first light source is optionally further configured to output a linearly polarized laser beam toward the first angle detector, and the second light source is optionally further configured to output a linearly polarized laser beam toward the second angle detector.

[0123] The foregoing is merely illustrative and various modifications can be made to the described implementation scheme. The foregoing implementation scheme can be implemented individually or in any combination.

Claims

1. A head-mounted device, the head-mounted device comprising: A first optical module, configured to output content to a first eye-friendly area; A second optical module is configured to output content to a second eye-friendly area; A support structure that attaches the first optical module to the second optical module, wherein the support structure includes at least a flexible portion that allows the first optical module and the second optical module to move relative to each other when flexed; A transmitter, which is disposed on the first optical module and configured to emit light; The detector includes: A patterned mask having a plurality of openings; and An image sensor, configured to receive light propagation through at least a portion of the plurality of openings in the patterned mask, to sense one or more corresponding diffraction patterns; and A control circuit configured to analyze one or more diffraction patterns sensed by the image sensor of the detector to determine the relative attitude displacement between the first optical module and the second optical module.

2. The head-mounted device of claim 1, wherein the transmitter comprises: A first light-emitting component, configured to emit light within a first wavelength range; A second light-emitting component is configured to emit light in a second wavelength range that is different from the first wavelength range; and A third light-emitting component is configured to emit light in a third wavelength range that is different from the first wavelength range and the second wavelength range.

3. The head-mounted device according to claim 2, wherein: The first light-emitting component is disposed at a first depth within the emitter; The second light-emitting component is disposed within the emitter at a second depth different from the first depth; and The third light-emitting component is disposed within the emitter at a third depth, different from the first depth and the second depth.

4. The head-mounted device according to claim 2, wherein: The first light-emitting component is selectively activated during the first time period; The second light-emitting component is selectively activated during a second time period following the first time period; and The third light-emitting component is selectively activated during a third time period following the second time period.

5. The head-mounted device according to claim 2, wherein: The first light-emitting component and the second light-emitting component are activated concurrently during the first time period; The second light-emitting component and the third light-emitting component are concurrently activated during a second time period following the first time period; and The first light-emitting component and the third light-emitting component are activated concurrently during a third time period following the second time period.

6. The head-mounted device of claim 1, wherein the detector comprises an additional patterned mask stacked on the patterned mask.

7. The head-mounted device of claim 1, wherein the control circuitry is configured to determine the relative posture displacement between the first optical module and the second optical module based on a model, the model being configured to analyze one or more of the following: geometric features of the one or more diffraction patterns, light intensity information of the one or more diffraction patterns, and physical constraints associated with the movement of the first optical module and the second optical module.

8. The head-mounted device according to claim 1, wherein the detector is disposed on the second optical module.

9. The head-mounted device of claim 1, wherein the detector is disposed on the first optical module, and wherein a reflective layer disposed on the second optical module is configured to reflect the light emitted from the transmitter back to the detector.

10. The head-mounted device of claim 1, wherein the transmitter comprises: An additional patterned mask having multiple openings; and A light source configured to output light that propagates through the plurality of openings in the additional patterned mask.

11. The head-mounted device according to claim 1, further comprising: A depth sensor is disposed at the first optical module or the second optical module, wherein the depth sensor is configured to output a depth value based on the distance between the first optical module and the second optical module, and wherein the control circuit is further configured to analyze the depth value to determine the relative posture displacement between the first optical module and the second optical module.

12. The head-mounted device according to claim 1, further comprising: An additional transmitter is disposed at the second optical module; and An additional detector is disposed at the first optical module, wherein the additional emitter is configured to emit light toward the additional detector, and wherein the control circuit is configured to analyze information measured by the additional detector to determine the relative attitude displacement between the first optical module and the second optical module.

13. The head-mounted device according to claim 1, further comprising: An additional detector is disposed at the second optical module and configured to receive the light from the transmitter, wherein the control circuit is further configured to analyze the information measured by the additional detector to determine the relative attitude displacement between the first optical module and the second optical module.

14. A head-mounted device, the head-mounted device comprising: A first optical module, configured to output content to a first eye-friendly area; A second optical module is configured to output content to a second eye-friendly area; A support structure that attaches the first optical module to the second optical module, wherein the support structure includes at least a flexible portion that allows the first optical module and the second optical module to move relative to each other when flexed; A light source, which is disposed on the first optical module and configured to output a coherent beam; A beam splitter configured to split the coherent beam into a first beam and a second beam; A reflector configured to reflect the first light beam; A semi-reflective mirror, which is disposed on the second optical module and configured to reflect a portion of the second light beam; A first detector is configured to sense an interference pattern generated by the phase shift difference between the first light beam reflected from the mirror and the portion of the second light beam reflected from the half-mirror. and A control circuit configured to analyze the interference pattern sensed by the first detector to determine the relative translational displacement between the first optical module and the second optical module.

15. The head-mounted device according to claim 14, further comprising: A second detector, configured to sense a portion of the second beam transmitted through the semi-reflective mirror, wherein: The first detector is configured to sense a first beam spot associated with a superimposed beam, the superimposed beam comprising a portion of the first beam reflected back from the mirror and a portion of the second beam reflected back from the half-mirror; The second detector is configured to sense the second beam spot associated with the portion of the second beam transmitted through the semi-reflective mirror; and The control circuit is configured to analyze the position of the first beam spot in the first detector and the position of the second beam spot in the second detector to determine the relative rotational displacement between the first optical module and the second optical module.

16. The head-mounted device of claim 14, wherein the coherent beam and the first beam propagate between the first optical module and the second optical module via a light guide, light waveguide, light tube, or waveguide between the first optical module and the second optical module.

17. The head-mounted device of claim 14, wherein the beam splitter, the reflector, and the first detector are disposed at an intermediate position between the first optical module and the second optical module.

18. The head-mounted device of claim 14, wherein the beam splitter, the reflector, and the first detector are disposed on the first optical module or the second optical module.

19. A head-mounted device, the head-mounted device comprising: A first optical module, configured to output content to a first eye-friendly area; A second optical module is configured to output content to a second eye-friendly area; A support structure that attaches the first optical module to the second optical module, wherein the support structure includes at least a flexible portion that allows the first optical module and the second optical module to move relative to each other when flexed; A rigid structure extending between the first optical module and the second optical module; A first angle detector is disposed at a first position on the rigid structure; A second angle detector is disposed at a second position on the rigid structure; A first light source is disposed on the first optical module and configured to output a first coherent beam toward the first angle detector; A second light source is disposed on the second optical module and configured to output a second coherent beam toward the second angle detector; and A control circuit configured to analyze the position of a first beam spot sensed by the first angle detector and the position of a second beam spot sensed by the second angle detector to determine the relative rotational displacement between the first optical module and the second optical module.

20. The head-mounted device according to claim 19, wherein: The first angle detector includes a first image sensor and one or more grating structures disposed above the first image sensor; The second angle detector includes a second image sensor and one or more grating structures disposed above the second image sensor; The first light source is further configured to output a linearly polarized laser beam toward the first angle detector; and The second light source is further configured to output a linearly polarized laser beam toward the second angle detector.

Images