Abstract: A display assembly monitors movements in a waveguide assembly and corrects for aberrations in image light caused by the monitored movements. For example, an artificial reality headset may include a display assembly that monitors for changes in shape or displacement of waveguide assemblies that generate three dimensional images for display with a real world environment. The display assembly includes movement sensors (e.g., piezoelectric movement sensors) coupled to the waveguide assembly. The movement sensors monitor the movement of the waveguide assembly and provide the monitored movement to a display controller that generates instructions for correcting aberrations in the image light.

Abstract: A display assembly monitors movements in a waveguide assembly and corrects for aberrations in image light caused by the monitored movements. For example, an artificial reality headset may include a display assembly that monitors for changes in shape or displacement of waveguide assemblies that generate three dimensional images for display with a real world environment. The display assembly includes movement sensors (e.g., piezoelectric movement sensors) coupled to the waveguide assembly. The movement sensors monitor the movement of the waveguide assembly and provide the monitored movement to a display controller that generates instructions for correcting aberrations in the image light.

Abstract: In certain embodiments, an accelerometer is a microelectromechanical systems (MEMS) device including a proof mass, an anchor located in an opening defined by a body of the proof mass, a spring, a drive electrode, and a sense beam. The spring and the proof mass form a spring system suspended from the anchor. The sense beam oscillates at a particular resonance frequency based on application of a signal to the drive electrode. The MEMS device further includes a support structure coupled to the anchor. The support structure operates as a stress decoupling area and includes a support beam, with the spring corresponding to an end of the support beam that has a reduced thickness. The sense beam has a first end attached to the proof mass and a second end attached to the support beam such that the sense beam is orthogonal to the support beam.

Abstract: A headset comprise a frame and a vibration sensor coupled to the frame. The vibration sensor may be located in a nosepad of the frame, and configured to measure tissue vibrations of a user when the headset of worn by the user. A controller receives a signal corresponding to the measured vibration data from the vibration sensor, and analyzes the received signal to infer a sequence of states of the received signal, such as a sequence of respiratory states. The controller further determines a value of a health metric based upon the inferred sequence of states, e.g., a respiratory rate of the user, and performs an action using the determined value of the health metric.

Abstract: A display assembly monitors movements in a waveguide assembly and corrects for aberrations in image light caused by the monitored movements. For example, an artificial reality headset may include a display assembly that monitors for changes in shape or displacement of waveguide assemblies that generate three dimensional images for display with a real world environment. The display assembly includes movement sensors (e.g., piezoelectric movement sensors) coupled to the waveguide assembly. The movement sensors monitor the movement of the waveguide assembly and provide the monitored movement to a display controller that generates instructions for correcting aberrations in the image light.

Abstract: A displacement sensor measures capacitance between a rotor-stator pair. The displacement sensor includes a plurality of stators coupled to a first object. The plurality of stators is oriented parallel to an axis of motion between the first object and a second object. The displacement sensor further includes a plurality of rotors coupled to the second object. The plurality of rotors is oriented parallel to the axis of motion. Each rotor of the plurality of rotors is aligned with and configured to receive a corresponding stator of the plurality of stators to create a respective rotor-stator pair. Capacitance between the rotor-stator pairs change as a function of position of the first object relative to the second object along the axis of motion. An amount of displacement of the first object relative to the second object is determined based in part on the capacitance values.

Abstract: An actuator aligned multi-channel projector assembly generates image light using a plurality of projectors. A projector includes a plurality of optical components in optical series and one or more actuators. The plurality of optical components include a light source and a plurality of optical elements. The light source generates first light. The plurality of optical elements project the first light. The first light is output from the projector and combined with a second to form an image presented via a display element of a headset to a user. The one or more actuators adjust a position of at least one optical component of the plurality of optical components relative to another optical component in order to compensate for misalignment of a portion of the image formed from the first light relative to a portion of the image formed from the second light.

Abstract: A piezoelectric microelectromechanical systems (MEMS) transducer that can operate as a microphone (e.g., contact microphone) or a speaker is presented herein. The piezoelectric MEMS transducer includes a substrate, a proof mass and folded displacement sensing structures. Each folded displacement sensing structure comprises a continuous beam, a first piezoelectric stress sensor coupled to a first portion of the continuous beam, and a second piezoelectric stress sensor coupled to a second portion of the continuous beam. The first portion of the continuous beam is coupled to a respective portion of the proof mass, and the second portion of the continuous beam is coupled to a respective portion of the substrate. The first and second portions of the continuous beam come together at an acute angle. The first and second piezoelectric stress sensors output stress information responsive to a stress induced in the continuous beam by displacement of the proof mass.

Abstract: Described herein are accelerometers, apparatus and systems incorporating accelerometers, and techniques for electrostatically adjusting a stiffness of a spring system in an accelerometer. Embodiments featuring resonant and/or quasi-static accelerometers are described. In certain embodiments, an accelerometer is a microelectromechanical systems (MEMS) device including a proof mass, an anchor, a spring attached to the proof mass, a sense electrode, and a tuning electrode. The spring and the proof mass form a spring system suspended from the anchor. The sense electrode is configured to generate a signal indicating movement of the proof mass based on application of a first signal. The tuning electrode is configured to receive an electrostatic tuning signal, the electrostatic tuning signal being separate from the first signal and providing a negative contribution to an overall stiffness of the spring system. The electrostatic tuning signal can be used to adjust the stiffness based on a measured acceleration.

Abstract: Described herein are accelerometers, apparatus and systems incorporating accelerometers, and techniques for controlling sensing operations in an accelerometer. In certain embodiments, an accelerometer is a microelectromechanical systems (MEMS) device including a proof mass, an anchor, a spring between the proof mass and the anchor, a drive electrode, and a sense beam. The anchor is located in an opening defined by a body of the proof mass. The spring and the proof mass form a spring system suspended from the anchor. The sense beam is configured to oscillate at a particular resonance frequency that changes according to a force generated by movement of the proof mass in response to acceleration. In some embodiments, a support structure couples the anchor to the spring and operates as a stress decoupling area that prevents or limits propagation of stress from the anchor to the sense beam and the spring system.

Abstract: A displacement sensor measures capacitance between a rotor-stator pair. The displacement sensor includes a plurality of stators coupled to a first object. The plurality of stators is oriented parallel to an axis of motion between the first object and a second object. The displacement sensor further includes a plurality of rotors coupled to the second object. The plurality of rotors is oriented parallel to the axis of motion. Each rotor of the plurality of rotors is aligned with and configured to receive a corresponding stator of the plurality of stators to create a respective rotor-stator pair. Capacitance between the rotor-stator pairs change as a function of position of the first object relative to the second object along the axis of motion. An amount of displacement of the first object relative to the second object is determined based in part on the capacitance values.