Patent ID: RE42916

Claim:
An angular rate sensor system which may be used with a signal processing circuit to discriminate an angular rate, the angular rate sensor system comprising: a mounting structure; and a vibratory sensing element including a substantially planar base electrode presenting a pair of opposing sides , at least two layers of piezoelectric material each disposed on and substantially covering the opposing sides of the base electrode, a first outer electrode disposed on a first side of the vibratory sensing element, and a second outer electrode disposed on a second side of the vibratory sensing element opposing the first side, the first outer electrode and the second outer electrode being oriented generally parallel with a plane, the vibratory sensing element defining a pair of natural acoustic nodes when vibrated in a direction of vibration oriented generally perpendicular to the plane, the vibratory sensing element being suspended from the mounting structure proximate to each of the pair of natural acoustic nodes so as to vibrate in the direction of vibration , said angular rate sensor system further comprising a third outer electrode, the third outer electrode being disposed on the first side of the vibratory sensing element and oriented generally parallel with the plane, and a fourth outer electrode, the fourth outer electrode being disposed on the second side of the vibratory sensing element and oriented generally parallel with the plane, whereby wherein the vibratory sensing element vibrates in the direction of vibration oriented generally perpendicular to the plane when either the first electrode or the second electrode are excited by a drive signal, and further whereby wherein the first electrode or the second electrode produce sensing signals responsive and proportional to the angular rate of the vibratory sensing element, the signal processing circuit discriminating the angular rate from the sensing signals.