Abstract: An in-situ test calibration system and method are disclosed where a perpetual out-of-band electrostatic force induced excitation is used to dither the proof-mass of a MEMS based accelerometer where the amount of deflection change is proportional to sensitivity changes. The supplier of the accelerometer would exercise the accelerometer in a calibration station to determine initial sensitivity values. After the calibration and before removing the accelerometer from the calibration station, the supplier would start the dither and calibrate the acceleration equivalent force (FG) to drive voltage transfer function (FG/V). After installation of the accelerometer into a system or sometime later in the field, any changes in the FG/V transfer function due to changes in the sensitivity are observable and can be used for re-calibrating the accelerometer.

Abstract: An electronic device may have components that experience performance variations as the device changes orientation relative to a user. Changes in the orientation of the device relative to the user can be monitored using a motion sensor. A camera may be used to periodically capture images of a user's eyes. By processing the images to produce accurate orientation information reflecting the position of the user's eyes relative to the device, the orientation of the device tracked by the motion sensor can be periodically updated. The components may include audio components such as microphones and speakers and may include a display with an array of pixels for displaying images. Control circuitry in the electronic device may modify pixel values for the pixels in the array to compensate for angle-of-view-dependent pixel appearance variations based on based on the orientation information from the motion sensor and the camera.

Abstract: An in-situ calibration system, method and apparatus is disclosed that uses test electrodes to stimulate a proof-mass of a MEMS based gyroscope at a drive frequency as quasi-Coriolis forces to extract the electromechanical gain, and uses a non-resonant carrier signal on the proof-mass to extract the additional changes in the sense and drive capacitance. Additionally, an in-situ calibration system, method and apparatus is disclosed that uses quadrature electrodes to apply a known force stimulus to the proof-mass as part of a calibration procedure, where the known force is applied again after installation into a system or further into the life of the gyroscope. Differences in the proof-mass response to the force are proportional to changes in sensitivity, which allows the sensitivity to be corrected in-field.

Abstract: A multi-stage MEMS accelerometer is disclosed that includes a MEMS sensor that has two suspended structures (proof masses) suspended by suspension members. The suspended structures move together in response to input acceleration when less the acceleration is less than a threshold value. When the input acceleration is greater than the threshold value, one of the suspended structures makes contact with a mechanical stop while the other suspended structure continues to move with increased stiffness due to the combined stiffness of the suspension members. The contact with the mechanical stop contributes a nonlinear mechanical stiffening effect that counteracts the nonlinear capacitive effect inherent in capacitive based MEMS accelerometers. In some embodiments, more than two suspended structures can be used to allow for optimization of sensitivity for multiple full-scale ranges, and for higher fidelity tuning of mechanical sensitivity with nonlinear capacitance.

Abstract: An in-situ test calibration system and method are disclosed where a perpetual out-of-band electrostatic force induced excitation is used to dither the proof-mass of a MEMS based accelerometer where the amount of deflection change is proportional to sensitivity changes. The supplier of the accelerometer would exercise the accelerometer in a calibration station to determine initial sensitivity values. After the calibration and before removing the accelerometer from the calibration station, the supplier would start the dither and calibrate the acceleration equivalent force (FG) to drive voltage transfer function (FG/V). After installation of the accelerometer into a system or sometime later in the field, any changes in the FG/V transfer function due to changes in the sensitivity are observable and can be used for re-calibrating the accelerometer.

Abstract: An in-situ calibration system, method and apparatus is disclosed that uses test electrodes to stimulate a proof-mass of a MEMS based gyroscope at a drive frequency as quasi-Coriolis forces to extract the electromechanical gain, and uses a non-resonant carrier signal on the proof-mass to extract the additional changes in the sense and drive capacitance. Additionally, an in-situ calibration system, method and apparatus is disclosed that uses quadrature electrodes to apply a known force stimulus to the proof-mass as part of a calibration procedure, where the known force is applied again after installation into a system or further into the life of the gyroscope. Differences in the proof-mass response to the force are proportional to changes in sensitivity, which allows the sensitivity to be corrected in-field.

Abstract: A multi-stage MEMS accelerometer is disclosed that includes a MEMS sensor that has two suspended structures (proof masses) suspended by suspension members. The suspended structures move together in response to input acceleration when less the acceleration is less than a threshold value. When the input acceleration is greater than the threshold value, one of the suspended structures makes contact with a mechanical stop while the other suspended structure continues to move with increased stiffness due to the combined stiffness of the suspension members. The contact with the mechanical stop contributes a nonlinear mechanical stiffening effect that counteracts the nonlinear capacitive effect inherent in capacitive based MEMS accelerometers. In some embodiments, more than two suspended structures can be used to allow for optimization of sensitivity for multiple full-scale ranges, and for higher fidelity tuning of mechanical sensitivity with nonlinear capacitance.

Abstract: An electronic device may have components that experience performance variations as the device changes orientation relative to a user. Changes in the orientation of the device relative to the user can be monitored using a motion sensor. A camera may be used to periodically capture images of a user's eyes. By processing the images to produce accurate orientation information reflecting the position of the user's eyes relative to the device, the orientation of the device tracked by the motion sensor can be periodically updated. The components may include audio components such as microphones and speakers and may include a display with an array of pixels for displaying images. Control circuitry in the electronic device may modify pixel values for the pixels in the array to compensate for angle-of-view-dependent pixel appearance variations based on based on the orientation information from the motion sensor and the camera.

Abstract: The cap wafer for a MEMS device includes multiple electrically isolated electrodes that can be bonded and electrically connected to separate electrical contacts on a MEMS device wafer. The electrically isolated electrodes can be used for any of a variety of functions, such as for apply a force to a movable MEMS structure on the MEMS device wafer (e.g., for driving resonance of the movable MEMS structure or for adjusting a resonance or sense mode of the movable MEMS structure) or for sensing motion of a movable MEMS structure on the MEMS device wafer. Since the electrodes are electrically isolated, different electrodes may be used for different functions.

Abstract: The cap wafer for a MEMS device includes multiple electrically isolated electrodes that can be bonded and electrically connected to separate electrical contacts on a MEMS device wafer. The electrically isolated electrodes can be used for any of a variety of functions, such as for apply a force to a movable MEMS structure on the MEMS device wafer (e.g., for driving resonance of the movable MEMS structure or for adjusting a resonance or sense mode of the movable MEMS structure) or for sensing motion of a movable MEMS structure on the MEMS device wafer. Since the electrodes are electrically isolated, different electrodes may be used for different functions.

Abstract: The cap wafer for a MEMS device includes multiple electrically isolated electrodes that can be bonded and electrically connected to separate electrical contacts on a MEMS device wafer. The electrically isolated electrodes can be used for any of a variety of functions, such as for apply a force to a movable MEMS structure on the MEMS device wafer (e.g., for driving resonance of the movable MEMS structure or for adjusting a resonance or sense mode of the movable MEMS structure) or for sensing motion of a movable MEMS structure on the MEMS device wafer. Since the electrodes are electrically isolated, different electrodes may be used for different functions.

Abstract: The cap wafer for a MEMS device includes multiple electrically isolated electrodes that can be bonded and electrically connected to separate electrical contacts on a MEMS device wafer. The electrically isolated electrodes can be used for any of a variety of functions, such as for apply a force to a movable MEMS structure on the MEMS device wafer (e.g., for driving resonance of the movable MEMS structure or for adjusting a resonance or sense mode of the movable MEMS structure) or for sensing motion of a movable MEMS structure on the MEMS device wafer. Since the electrodes are electrically isolated, different electrodes may be used for different functions.

Abstract: Microstructures can be formed as patterned layers on a substrate and then erecting the microstructures out of the plane of the substrate. The microstructures may be formed over circuits in the substrate. In some embodiments the patterned layer provides resiliently-flexible members such as cantilevers or springs that can be buckled to permit an edge defined by the patterned layer to engage a surface of the substrate. In some embodiments deformation of the resiliently-flexible members results the edge being forced against the substrate. Such microstructures may be applied in a wide range of applications including supporting optical elements, sensors, antennas or the like out of the plane of a substrate. Examples of accelerometer structures are described.

Abstract: Microstructures can be formed as patterned layers on a substrate and then erecting the microstructures out of the plane of the substrate. The microstructures may be formed over circuits in the substrate. In some embodiments the patterned layer provides resiliently-flexible members such as cantilevers or springs that can be buckled to permit an edge defined by the patterned layer to engage a surface of the substrate. In some embodiments deformation of the resiliently-flexible members results the edge being forced against the substrate. Such microstructures may be applied in a wide range of applications including supporting optical elements, sensors, antennas or the like out of the plane of a substrate. Examples of accelerometer structures are described.