Micromechanical inertial sensor having reduced sensitivity to the influence of drifting surface charges, and method suited for operation thereof
First Claim
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1. A micromechanical inertial sensor, comprising:
- at least one seismic mass which may be deflected relative to a substrate;
at least one electrode surface which in terms of circuitry, together with at least portions of the seismic mass, forms at least one capacitor having a capacitance which is dependent on a deflection of the seismic mass; and
at least one additional auxiliary electrode located outside a region which forms the capacitor and which may be set at a potential that deviates from a potential of the seismic mass, wherein the potential of the auxiliary electrode is set by an output of the sensor when a test voltage is applied to the auxiliary electrode.
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Abstract
A micromechanical inertial sensor having at least one seismic mass which may be deflected relative to a substrate, and at least one electrode surface which in terms of circuitry, together with at least portions of the seismic mass forms at least one capacitor having a capacitance which is dependent on the deflection of the seismic mass. At least one additional auxiliary electrode is included which is located outside the region which forms the capacitor and which may be set at a potential that deviates from the potential of the seismic mass.
23 Citations
18 Claims
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1. A micromechanical inertial sensor, comprising:
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at least one seismic mass which may be deflected relative to a substrate; at least one electrode surface which in terms of circuitry, together with at least portions of the seismic mass, forms at least one capacitor having a capacitance which is dependent on a deflection of the seismic mass; and at least one additional auxiliary electrode located outside a region which forms the capacitor and which may be set at a potential that deviates from a potential of the seismic mass, wherein the potential of the auxiliary electrode is set by an output of the sensor when a test voltage is applied to the auxiliary electrode. - View Dependent Claims (2, 3, 4, 15, 16, 17, 18)
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5. A method for reducing an influence of drifting surface charges on an output signal from a micromechanical Z sensor, comprising:
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using a seismic mass in a form of an asymmetric rocker which may be rotated about a torsion spring, surface regions of the rocker which are symmetrical with respect to a rotational axis extending parallel to at least one symmetrical electrode pair, and in terms of circuitry together with electrode pair forming capacitors having a capacitance that is dependent on a deflection of the seismic mass, and at least one additional surface region of the rocker being situated opposite an auxiliary electrode which is located in a fixed position with respect to a substrate outside a region of the electrodes that are part of the capacitors; measuring an acceleration in a Z direction by evaluating the capacitance of at least one of the capacitors; and setting, at least during the measurement of acceleration, the auxiliary electrode at a potential that deviates from a potential of the seismic mass, wherein the potential of the auxiliary electrode is set by an output of the Z sensor when a test voltage is applied to the auxiliary electrode. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification