Micromachined cantilever structure providing for independent

Abstract

A micromachined structure providing for independent vertical and lateral deflection sensing. The structure uses high aspect ratio ribs which bend much more easily in one direction than in other directions (i.e., have a predominant direction of compliance). One or more ribs are combined to form beams which also have one predominant direction of compliance. Two such beams are bonded end to end, and one end of the beam pair is bonded to a base. The beams are oriented orthogonally to one another such that they independently bend to vertical and lateral external forces. Further, three dimensional force sensing can be accomplished by adding a third beam. Sensors can independently sense the bending in each beam and thereby independently measure the dimensional components of bending forces applied to the free end of the structure. In the preferred embodiment, piezoresistive sensors are formed on the ribs comprising the beams. The piezoresistors can be made by ion-implantation, for example. Measurement of the change in resistance of the sensors is then a measure of the beam deflection and the external force. The resistances of the sensors can be measured independently. Other sensing means include voltage measurement of piezoelectric effects, optical deflection and interference sensing techniques, and capacitive deflection sensors.