MEMS inclinometer having a reduced vibration rectification error
AssigneeSTMicroelectronics S.r.l.
InventorsGabriele Gattere, Francesco Rizzini
Life of this patent
Estimating the term…
Abstract
A MEMS inclinometer includes a substrate, a first mobile mass and a sensing unit. The sensing unit includes a second mobile mass, a number of elastic elements, which are interposed between the second mobile mass and the substrate and are compliant in a direction parallel to a first axis, and a number of elastic structures, each of which is interposed between the first and second mobile masses and is compliant in a direction parallel to the first axis and to a second axis. The sensing unit further includes a fixed electrode that is fixed with respect to the substrate and a mobile electrode fixed with respect to the second mobile mass, which form a variable capacitor.
Claims20
A Micro Electro-Mechanical System (MEMS) inclinometer, comprising:
- a substrate;
- a first mobile mass suspended over the substrate and subject, in use, to an acceleration that depends upon an inclination of the inclinometer;
- and
- a first sensing unit including:
- a second mobile mass, suspended over the substrate;
- a plurality of elastic elements, each of which is mechanically interposed between the second mobile mass and the substrate and is compliant in a direction parallel to a first axis;
- a plurality of elastic structures coupling the first and second mobile masses compliant in the direction parallel to the first axis and to a second axis;
- at least one first fixed electrode that is fixed with respect to the substrate;
- and
- at least one first mobile electrode that is fixed with respect to the second mobile mass and configured to form a first variable capacitor with said first fixed electrode,
- wherein each elastic structure includes at least one respective elongated structure, which, in resting conditions, extends in a direction parallel to a third axis and, in a plane parallel to a plane containing the first axis and the second axis, has main axes of inertia which are transverse with respect to the first and second axes, so that movements of the first mobile mass in a direction parallel to the second axis, caused by said acceleration, cause corresponding movements of the second mobile mass in a direction parallel to the first axis.
A Micro Electro-Mechanical System (MEMS) inclinometer, comprising:
- a substrate;
- a first mobile mass suspended over the substrate and subject, in use, to an acceleration that depends upon an inclination of the inclinometer;
- and
- a first sensing unit including:
- a cross-shaped second mobile mass 7 suspended over the substrate, including:
- a central cavity;
- a first arm extending along a first direction that is parallel to a first axis;
- and
- a second arm extending along a second direction that is parallel to a second axis, the first axis being perpendicular to the second axis;
- a first elastic element mechanically coupled between a first side of the second arm of the second mobile mass and the substrate, the first elastic element being compliant along the first direction;
- a second elastic element mechanically coupled between a second side of the second arm of the second mobile mass and the substrate, the second elastic element being compliant along the first direction, the second side being opposite the first side along the first direction;
- a third elastic element mechanically coupled between the first side of the second arm of the second mobile mass and the substrate, the third elastic element being compliant along the first direction, the first arm of the second mobile mass disposed between the first elastic element and the third elastic element;
- a fourth elastic element mechanically coupled between the second side of the second arm of the second mobile mass and the substrate, the fourth elastic element being compliant along the first direction, the first arm of the second mobile mass disposed between the second elastic element and the fourth elastic element;
- a plurality of elastic structures coupling the first and second mobile masses compliant along the first direction and rigid along the second direction, the plurality of elastic structures extending from the second arm in the first direction to the first mobile mass;
- at least one first fixed electrode that is fixed with respect to the substrate, the at least one fixed electrode being in the central cavity of the second mobile mass;
- and
- at least one first mobile electrode that is fixed with respect to the second mobile mass and configured to form a first variable capacitor with the first fixed electrode.
Dependencies are inferred from the claim text.