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Capacitive micromechanical sensor structure and micromechanical accelerometer

  • US 9,547,020 B2
  • Filed: 06/25/2014
  • Issued: 01/17/2017
  • Est. Priority Date: 06/28/2013
  • Status: Active Grant
First Claim
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1. A capacitive micromechanical sensor structure comprising:

  • a stator structure rigidly anchored to a substrate and a rotor structure movably anchored by spring structures to the substrate,the stator structure having a plurality of stator finger support beams,the rotor structure having a plurality of rotor finger support beams,a stator finger support beam of the stator structure comprising a stator finger structure along at least one side of the stator finger support beam, wherein the stator finger structure comprises a plurality of stator fingers and stator gaps between two adjacent stator fingers,a rotor finger support beam of the rotor structure comprising a rotor finger structure along at least one side of the rotor finger support beam, wherein the rotor finger structure comprises a plurality of rotor fingers and rotor gaps between two adjacent rotor fingers,stator fingers along the stator finger support beam of the stator structure extending into rotor gaps along the rotor finger support beam of the rotor structure,rotor fingers along the rotor finger support beam of the rotor structure extending into stator gaps along the stator finger support beam of the stator structure;

    characterized bya stator fingertip gap between the stator fingers of the stator finger structure and the rotor finger support beam being in unloaded state of the capacitive micromechanical sensor structure one to 2.5 times a finger side gap between the stator fingers of the stator finger structure and the rotor fingers of the rotor finger structure, anda rotor fingertip gap between the rotor fingers of the rotor finger structure and the stator finger support beam being in unloaded state of the capacitive micromechanical sensor structure one to 2.5 times the finger side gap between the stator fingers of the stator finger structure and the rotor fingers of the rotor finger structure, andthe rotor structure being movably anchored to the substrate in such way that the rotor structure can be deflected at least parallel with the plane of the substrate so that the rotor fingertip gap between the rotor fingers along at least one side of the rotor finger support beam and the stator finger support beam changes, the stator fingertip gap between the stator fingers along at least one side of the stator finger support beam and the rotor finger support beam changes, and a finger overlap length changes, the finger overlap length being the length the stator fingers of the stator finger structure extend into the rotor gaps of the rotor finger structure, or alternatively the length the rotor fingers of the rotor finger structure extend into the stator gaps of the stator finger structure, andwherein stopper bumps configured to prevent excess movement of the rotor structure with respect to the stator structure but allowing the rotor structure to move in two opposite directions a distance corresponding to a stopper gap that isgreater than 0.25 times the finger side gap between stator fingers of the stator finger structure along the side of the stator finger support beam and a rotor finger of the rotor finger structure along the side of the rotor finger support beam, andless than the rotor fingertip gap and less than the stator fingertip gap.

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