Optically transduced MEMS magnetometer
| DWPI Title: Micro electro-mechanical system device e.g. optically transduced micro electro-mechanical system magnetometer, has grating extended from support and placed over resonator, and drive electrodes driving alternating current through resonator |
| Abstract: MEMS magnetometers with optically transduced resonator displacement are described herein. Improved sensitivity, crosstalk reduction, and extended dynamic range may be achieved with devices including a deflectable resonator suspended from the support, a first grating extending from the support and disposed over the resonator, a pair of drive electrodes to drive an alternating current through the resonator, and a second grating in the resonator overlapping the first grating to form a multi-layer grating having apertures that vary dimensionally in response to deflection occurring as the resonator mechanically resonates in a plane parallel to the first grating in the presence of a magnetic field as a function of the Lorentz force resulting from the alternating current. A plurality of such multi-layer gratings may be disposed across a length of the resonator to provide greater dynamic range and/or accommodate fabrication tolerances. |
| Use: Micro electro-mechanical system (MEMS) device e.g. MEMS force and inertial sensor such as MEMS magnetometer (claimed) e.g. optically transduced MEMS magnetometer or Lorentz force magnetometer. |
| Advantage: The device allows the multi-layer grating to be placed at locations of the resonator to experience different degrees of deflection by the Lorentz force, thus enabling large dynamic range of magnetic field strength to be optically transduced via light intensity modulation for satisfying predetermined threshold criteria, and hence improving sensitivity to the magnetic field, while accommodating fabrication tolerances. The device is designed such that phase between the first and second gratings of each multi-layer grating can be varied to account for fabrication variation and can ensure the multi-layer grating to provide a threshold level of light intensity modulation with resonator displacement. The device allows legs of an anchor to be ideally located in vicinity of a nodal point of a desired resonant mode so as to reduce energy losses in the desired resonant mode of the resonator. The device allows a reference detector to provide an electrical output signal to be combined with an electrical output signal of a detector to remove common-mode noise due to a light source, thus improving sensitivity for sensing relative displacement of the second grating placed on the resonator, while reducing crosstalk. |
| Novelty: The device has a deflectable resonator suspended from a support. A first grating (144A) is extended from the support and placed over the resonator. A set of drive electrodes drives an alternating current through the resonator. A second grating (154A) is placed in the resonator, where the gratings overlap to form a multi-layer grating (122A) with apertures that vary dimensionally in response to deflection occurring as the resonator mechanically resonates in a plane parallel to the first grating in presence of magnetic field as function of Lorentz force induced by the alternating current. |
| Filed: 12/14/2011 |
| Application Number: US13326139A |
| Tech ID: SD 11476.0 |
| 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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