Optically transduced MEMS gyro device
| DWPI Title: Bulk micromachined vibratory gyro for use in inertial sensor, has grating placed in proof mass layer, where grating and another grating overlap to form multi-layer grating with apertures varying dimensionally in response to rotation of gyro |
| Abstract: A bulk micromachined vibratory gyro in which a proof mass has a bulk substrate thickness for a large mass and high inertial sensitivity. In embodiments, optical displacement transduction is with multi-layer sub-wavelength gratings for high sensitivity and low cross-talk with non-optical drive elements. In embodiments, the vibratory gyro includes a plurality of multi-layer sub-wavelength gratings and a plurality of drive electrodes to measure motion of the proof mass induced by drive forces and/or moments and induced by the Coriolis Effect when the gyro experiences a rotation. In embodiments, phase is varied across the plurality gratings and a multi-layer grating having the best performance is selected from the plurality. |
| Use: Bulk micromachined vibratory optically transduced micro electro-mechanical system (MEMS) gyro for use in an inertial sensor (claimed) i.e. multi-axis inertial sensor, utilized for sensing angular velocity or angular acceleration generated by rotation of a movable body. |
| Advantage: The gyro varies phase across an arrayed multi-layer gratings to enable an inertial sensing system incorporating the bulk micromachined vibratory gyro to undergo functional test in which the gratings in an array can be binned out to identify the grating having a phase that satisfies predetermined threshold criteria in greatest displacement induced modulation of light intensity, thus improving sensitivity for sensing relative displacement of the grating placed on the proof mass. The gyro allows electrically independent support faces to be driven by different signals to capacitively impart torque on the suspended proof mass to maximize orthogonality of the drive and sense modes to reduce cross-talk. |
| Novelty: The gyro (100) has a first grating (144A) placed in a layer of a support (101), where a proof mass (105) is attached to the support via a flexure to oscillate relative to the support in response to drive force. A second grating (154A) is placed in a layer of the proof mass, where the gratings overlap to form a multi-layer sub-wavelength grating (124A) with multi-layer grating apertures that vary dimensionally in response to rotation of the gyro, and width of the apertures along a dimension of a plane of the support orthogonal to another dimension is varied in response to the rotation. |
| Filed: 12/14/2011 |
| Application Number: US13325683A |
| Tech ID: SD 11475.0 |
| This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The Government has certain rights in the invention. |
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