Torsion beam accelerometer

摘要

The accelerometer comprises a planar substrate (10) with a sensing part positioned above and parallel to the substrate and rotatable about a flexure axis. Part of the sensing part on one side of the flexure axis is larger in area than the part of the sensing part on the other side of the flexure axis. Two conductive surfaces are arranged symmetrically on the substrate about the flexure axis. The second conductive surface (18) co-acts with the larger side of the sensing part to define a heavy side deflection capacitor. The first conductive surface co-acts with the other side of the sensing part to define a light side deflection capacitor. An isolation device limits the electrical geometry of the heavy side capacitor to the physical geometry of the first conductive surface in one dimension. The sensing part rotates about the flexure axis and is responsive to acceleration normal to the surface of the substrate. The capacitance of the heavy side and light side capacitors change in response to the rotation.