Quadrature compensation
First Claim
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1. A microelectromechanical sensor device, comprising:
- a seismic mass;
a spring structure for suspending the seismic mass into a static support structure, wherein the spring structure defines for the seismic mass a drive direction, and a sense direction that is perpendicular to the drive direction;
an excitation element for driving the seismic mass into a linear drive oscillation, the drive oscillation having a direction which has a primary component in the drive direction and a secondary component by quadrature error in the sense direction;
a sense element for sensing a movement of the seismic mass because of a Coriolis force resulting from angular motion of the microelectromechanical sensor device;
a capacitive transducer structure that includes;
a stator to be anchored to the static support structure, wherein the stator includes a slanted first stator element and a slanted second stator element,a rotor mechanically connected to the seismic mass, wherein the rotor includes a first rotor element positioned opposite the first stator element, and a second rotor element positioned opposite the second stator element, wherein the first rotor element and the first stator element form a first capacitive transducer in which capacitance increases in phase with displacements of a drive direction oscillation, and the second rotor element and the second stator element form a second capacitive transducer in which capacitance increases in opposite phase with displacements of the drive direction oscillation; and
an electrical energy source connected to create a voltage between the stator and the rotor,wherein a first electrostatic force directed against the secondary component of the linear drive oscillation is created between the first stator element and the first rotor element of the first capacitive transducer, a second electrostatic force directed against the secondary component of the linear drive oscillation is created between the second stator element and the second rotor element of the second capacitive transducer, and the first electrostatic force is opposite to the second electrostatic force, andwherein the first capacitive transducer and the second capacitive transducer are configured into a slanted orientation in which a non-zero angle is formed between the drive direction and a tangent of the slanted first stator element, wherein the non-zero angle is formed between the drive direction and a tangent of the slanted second stator element, and the slanted first stator element and the slanted second stator element are parallel, whereby the first electrostatic force against the secondary component of the linear drive oscillation becomes gap modulated in phase with displacements of the drive direction oscillation, and the second electrostatic force against the secondary component of the linear drive oscillation becomes gap modulated in opposite phase with displacements of the drive direction oscillation.
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Abstract
A microelectromechanical sensor device that comprises a seismic mass, and a spring structure that defines for the seismic mass a drive direction, and a sense direction that is perpendicular to the drive direction. A capacitive transducer structure includes a stator to be anchored to a static support structure, and a rotor mechanically connected to the seismic mass. The capacitive transducer structure is arranged into a slanted orientation where a non-zero angle is formed between the drive direction and a tangent of the stator surface. The slated capacitive transducer structure creates an electrostatic force to decrease quadrature error of the linear oscillation.
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Citations
13 Claims
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1. A microelectromechanical sensor device, comprising:
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a seismic mass; a spring structure for suspending the seismic mass into a static support structure, wherein the spring structure defines for the seismic mass a drive direction, and a sense direction that is perpendicular to the drive direction; an excitation element for driving the seismic mass into a linear drive oscillation, the drive oscillation having a direction which has a primary component in the drive direction and a secondary component by quadrature error in the sense direction; a sense element for sensing a movement of the seismic mass because of a Coriolis force resulting from angular motion of the microelectromechanical sensor device; a capacitive transducer structure that includes; a stator to be anchored to the static support structure, wherein the stator includes a slanted first stator element and a slanted second stator element, a rotor mechanically connected to the seismic mass, wherein the rotor includes a first rotor element positioned opposite the first stator element, and a second rotor element positioned opposite the second stator element, wherein the first rotor element and the first stator element form a first capacitive transducer in which capacitance increases in phase with displacements of a drive direction oscillation, and the second rotor element and the second stator element form a second capacitive transducer in which capacitance increases in opposite phase with displacements of the drive direction oscillation; and an electrical energy source connected to create a voltage between the stator and the rotor, wherein a first electrostatic force directed against the secondary component of the linear drive oscillation is created between the first stator element and the first rotor element of the first capacitive transducer, a second electrostatic force directed against the secondary component of the linear drive oscillation is created between the second stator element and the second rotor element of the second capacitive transducer, and the first electrostatic force is opposite to the second electrostatic force, and wherein the first capacitive transducer and the second capacitive transducer are configured into a slanted orientation in which a non-zero angle is formed between the drive direction and a tangent of the slanted first stator element, wherein the non-zero angle is formed between the drive direction and a tangent of the slanted second stator element, and the slanted first stator element and the slanted second stator element are parallel, whereby the first electrostatic force against the secondary component of the linear drive oscillation becomes gap modulated in phase with displacements of the drive direction oscillation, and the second electrostatic force against the secondary component of the linear drive oscillation becomes gap modulated in opposite phase with displacements of the drive direction oscillation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification