Patents Represented by Law Firm Pillsbury Madiosn & Sutro LLP
  • Patent number: 5962788
    Abstract: A force transducer in which a deflectable seismic mass is supported on a frame by support means is disclosed. The seismic mass at rest includes a plane and when the seismic mass is deflected by any force the mass always retains the plane parallel to the rest position. Any deflection of the seismic mass is purely topographically translational movement with no rotational movement allowed. The invention allows three identical structures to be etched onto a flat semiconductor wafer and yet can be used to determine accelerations in three perpendicular directions. As the structures deflect, the surfaces of their seismic masses always remain parallel to the wafer surface. This enables measurement of the deflection to be made easily, for example by depositing electrodes on the surfaces of the seismic masses and fixed surfaces (such as deflection stops) and measuring the change in capacitance between the electrodes.
    Type: Grant
    Filed: January 31, 1997
    Date of Patent: October 5, 1999
    Assignee: BTG International Limited
    Inventor: John Neville Fawcett