A micro electro mechanical system device comprising:
- a substrate including a first main surface and a second main surface facing the first main surface;
- a recessed portion recessed from the first main surface toward the second main surface relative to the substrate;
- and
- a sensor unit positioned in the recessed portion, wherein
- the sensor unit includes
- a first drive frame excited in a first direction,
- a second drive frame mechanically connected to the first drive frame through a coupling spring and excited in the first direction in a phase opposite a phase of the first drive frame,
- a first detection frame mechanically connected to the first drive frame through a first drive spring, displaceable in the first direction along with the first drive frame, and displaceable in a second direction orthogonal to the first direction relative to the first drive frame,
- a second detection frame mechanically connected to the second drive frame through a second drive spring, displaceable in the first direction along with the second drive frame, and displaceable in the second direction relative to the second drive frame,
- a first fixation frame supported in such a manner that the first fixation frame is not movable relative to a wall surface defining the recessed portion,
- a second fixation frame supported in such a manner that the second fixation frame is not movable relative to the wall surface defining the recessed portion,
- a first excitation unit that uses electrostatic attraction to excite the first drive frame in the first direction,
- a second excitation unit that uses electrostatic attraction to excite the second drive frame in the first direction in a phase opposite a phase in the excitation by the first excitation unit,
- a first movable electrode extending in the first direction from the first detection frame,
- a second movable electrode extending in the first direction from the second detection frame and electrically insulated from the first movable electrode,
- a first fixation electrode extending in the first direction from the first fixation frame and facing the first movable electrode from a first side in the second direction,
- a second fixation electrode extending in the first direction from the first fixation frame, facing the first movable electrode from a second side opposite the first side in the second direction, and electrically insulated from the first fixation electrode,
- a third fixation electrode extending in the first direction from the second fixation frame and facing the second movable electrode from the first side in the second direction, potential of the third fixation electrode being the same as potential of the first fixation electrode, and
- a fourth fixation electrode extending in the first direction from the second fixation frame and facing the second movable electrode from the second side in the second direction, potential of the fourth fixation electrode being the same as potential of the second fixation electrode,
- each of the first fixation electrode and the second fixation electrode is coupled to the first fixation frame through an isolation joint, the isolation joint being configured to electrically insulate and mechanically couple two members, and
- each of the third fixation electrode and the fourth fixation electrode is coupled to the second fixation frame through the isolation joint.