Closed loop accelerometer
AssigneePhysical Logic AG
InventorsLisa KOENIGSBERG, Boris GRINBERG, Aviram FEINGOLD, Roza WOLFSON
Life of this patent
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Abstract
A micro-mechanical electrical systems (MEMS) type accelerometer for measuring vibration and movement employs a closed loop measurement mode. The accelerometer comprises at least one capacitive section configured as a sensing section and at least one capacitive section configured as an actuator section. In embodiments of the accelerometer capacitor plates are arranged in a bilateral structure in both the sensing and actuator sections. This structure combined with the capacitive feedback provided by the closed loop operation and other features of the device allow for a much larger sensing range in addition to other advantages over presently available MEMS accelerometers.
Claims13
A closed circuit accelerometer comprised of a composite structure, the composite structure comprising at least one capacitive section configured as a sensing structure and at least one capacitive section configured as an actuator structure, the composite structure comprised of a common proof mass and a single set of springs and manufactured as an in-plane silicon micro-mechanical electrical systems (MEMS) device, wherein the capacitive sections are connected together mechanically and isolated electrically;
- wherein the accelerometer comprises electronic circuits that provide a full bridge differential capacitive circuit to both the sensing section and the actuator section thereby enabling closed loop operation by using capacitance due to displacement of a proof mass in the sensing section to determine an electrostatic force that is applied by sending a voltage to the actuator section to nullify the displacement of the proof mass in the sensing section.
An actuator structure for use in a micro-mechanical electrical systems (MEMS) accelerator, the actuator structure comprising a capacitive section comprised of:
- a) a planar substrate;
- b) a plurality of capacitive plates that extend bilaterally from a plurality of support arms, which extend upwards from and are supported by and are attached to the substrate;
- and
- c) a plurality of capacitive plates that extend bilaterally from a plurality of support arms, which are attached to a proof mass frame;
- wherein, the support arms attached to the substrate and the support arms which are attached to the proof mass frame are configured such that their respective attached capacitive plates are disposed centro-symmetrically about the geometric center of the MEMS device and interlaced with each other, thereby forming very dense electrodes.
Dependencies are inferred from the claim text.