One-axis and two-axis rotation rate sensor
A sensor includes a substrate having a first electrode arrangement; a first mass oscillator having (a) a first mass, (b) a first mass centroid, and (c) a second electrode arrangement including a first area centroid coinciding with the first mass centroid; and a second mass oscillator having (a) a second mass equal to the first mass, (b) a second mass centroid coinciding with the first mass centroid, and (c) a third electrode arrangement including a second area centroid coinciding with the first area centroid. Areas of the second and third electrode arrangements are equal. The sensor detects respective rotation rates around axes parallel to and perpendicular to a substrate extension. The oscillators are oscillatorily connected to each other and to the substrate, are deflectable, and experience respective forces in the directions of extension of the axes upon respective rotations around the other of the axes.
1. A rotation rate sensor comprising:
a substrate that includes a first electrode arrangement;
a first mass oscillator that includes:
a first mass;
a first mass centroid; and
a second electrode arrangement that includes a first area centroid that coincides with the first mass centroid; and
a second mass oscillator that includes:
a second mass that is equal to the first mass;
a second mass centroid that coincides with the first mass centroid; and
a third electrode arrangement that includes a second area centroid that coincides with the first area centroid;
wherein:
an area of the third electrode arrangement is equal to an area of the second electrode arrangement;
the rotation rate sensor is configured to detect a first rotation rate around a first rotational axis that extends along a direction that is essentially parallel to a main plane of extension of the substrate and/or a second rotation rate around a second rotational axis that extends along a direction that is essentially perpendicular to the main plane of extension; and
the first and second mass oscillators:
are oscillatorily connected to each other and to the substrate;
are deflectable in a drive movement direction in counter-phase along a direction that is perpendicular to the directions of extension of each of the first and second rotational axes;
experience a first force in the direction of extension of the second rotational axis upon a rotation around the first rotational axis; and
experience a second force in the direction of extension of the first rotational axis upon a rotation around the second rotational axis.
2. The rotation rate sensor of claim 1 , wherein:
the first force results in a first detection movement of the first and second mass oscillators, in the direction of extension of the second rotational axis;
the first detection movement is linked to a first capacitance change, which is between the first and second electrode arrangements, and to a second capacitance change, which is between the first and third electrode arrangements;
the second force results in a second detection movement of the first and second mass oscillators, in the direction of extension of the first rotational axis;
the second detection movement is linked to a third capacitance change, which is between the first and second electrode arrangements, and to a fourth capacitance change, which is between first and third electrode arrangements;
the first rotation rate is measurable by a differential evaluation of the first and second capacitance changes; and
the second rotation rate is measurable by a differential evaluation of the third and fourth capacitance changes.
3. The rotation rate sensor of claim 1 , further comprising:
a first drive frame that is deflectable in the drive movement direction and oscillatorily coupled to the first and second mass oscillators.
4. The rotation rate sensor of claim 1 , further comprising:
a first drive frame that is deflectable in the drive movement direction and oscillatorily coupled to the first mass oscillator; and
a second drive frame that is deflectable in the drive movement direction and oscillatorily coupled to the second mass oscillator.