摘要 |
A rate sensor has a tine (2) cut from a silicon substrate (1) and resiliently mounted by two integral flexure beams (5 and 6). An electrostatic actuator (8) drives the tine to vibrate in its plane. The tine supports two tunnel pick-offs in the form of spikes (21 and 21') projecting from the tine, the tips of the spikes being positioned below a pick-off plate (22). In operation, the plate (22) is moved down until it is closely spaced from the spikes and a tunnelling current is produced. One spike (21) is positioned below a recess (52) so that there is a sharp fall in current when the spike passes beneath the recess, this signal being used to indicate the amplitude and frequency of vibration. The tunnelling current output from the other spike (21') indicates the separation from the plate. Rotation of the sensor about an axis (y) in the plane of vibration of the tine (2) causes displacement of the tine at right angles, which is sensed by the tunnel pick-off.
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