Patent ID: 6631643
Filing Date: 2003-10-14
Classification: G01P

Abstract:
An accelerometer havinga substantially planar plate-like proof mass, four or more flexible mounting legs each co-planar with the proof mass, a substantially planar, ring-like support, in which the proof mass is movably mounted, which support is fixedly mounted relative to the proof mass and co-planar therewith, with each mounting leg being connected at one end to the proof mass and connected at another end to the support so that the proof mass is mounted for linear movement in a sensing direction in the plane containing the proof mass, mounting legs and support, in response to acceleration change applied to the accelerometer, and with the mounting legs extending substantially perpendicularly to the sensing direction, at least two spaced apart substantially planar capacitor plates, mounted in the ring-like support substantially transverse to the sensing direction with the proof mass located between the capacitor plates and with each capacitor plate being co-planar with the proof mass, mounting legs and support, for sensing linear movement of the proof mass in the sensing direction, a plurality of inter-digitated fingers in air, comprising first arrays of laterally spaced fingers extending substantially perpendicularly to the sensing direction from the support towards the proof mass and second arrays of laterally spaced fingers extending substantially perpendicularly to the sensing direction from the proof mass towards the support, with the first arrays of fingers being interdigitated with the adjacent second arrays of fingers to provide air squeeze damping for movement of the proof mass in the sensing direction relative to the support, with the proof mass, mounting legs, support capacitor plates and inter-digitated fingers are formed from a single plate of silicon, and restoring means for returning the proof mass in the sensing direction towards a null position.