Microelectromechanical three-axis capacitive accelerometer
First Claim
1. A micromechanical structure, comprising:
- a substrate;
a mass having a main extension in a plane suspended above said substrate, the plane having a first direction and a second direction, the mass having;
a center line along the first direction;
a plurality of first openings;
a plurality of second openings separated from the plurality of first openings by the center line, a first one of the plurality of second openings being positioned adjacent to a second one of the plurality of second openings, the first one and the second one of the second openings having a same length in the first direction, a first width of the first one of the second openings being larger than a second width of the second one of the second openings, the first and second width both extending along the second direction, a first portion of the mass separating the first one of the second openings from the second one of the second openings and forming a first mobile electrode;
a first pair of fixed electrodes formed on the substrate, the first pair of fixed electrodes configured to extend into the first one of the second openings to interact with the first mobile electrode;
coupling elastic elements;
anchorages attached to the substrate;
elastic anchorage elements;
a frame element, elastically coupled to said mass by the coupling elastic elements and coupled to the anchorages by the elastic anchorage elements, said coupling elastic elements and said anchorage elastic elements are configured to enable a first inertial movement of said mass in response to a first external acceleration in the first direction, and to enable a second inertial movement of said mass in response to a second external acceleration in a third direction transverse to said plane.
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Accused Products
Abstract
A micromechanical structure for a MEMS structure is provided with: a substrate; a single inertial mass having a main extension in a plane and arranged suspended above the substrate; and a frame element, elastically coupled to the inertial mass by coupling elastic elements and to anchorages, which are fixed with respect to the substrate by anchorage elastic elements. The coupling elastic elements and the anchorage elastic elements are configured so as to enable a first inertial movement of the inertial mass in response to a first external acceleration acting in a direction lying in the plane and also a second inertial movement of the inertial mass in response to a second external acceleration acting in a direction transverse to the plane.
22 Citations
24 Claims
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1. A micromechanical structure, comprising:
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a substrate; a mass having a main extension in a plane suspended above said substrate, the plane having a first direction and a second direction, the mass having; a center line along the first direction; a plurality of first openings; a plurality of second openings separated from the plurality of first openings by the center line, a first one of the plurality of second openings being positioned adjacent to a second one of the plurality of second openings, the first one and the second one of the second openings having a same length in the first direction, a first width of the first one of the second openings being larger than a second width of the second one of the second openings, the first and second width both extending along the second direction, a first portion of the mass separating the first one of the second openings from the second one of the second openings and forming a first mobile electrode; a first pair of fixed electrodes formed on the substrate, the first pair of fixed electrodes configured to extend into the first one of the second openings to interact with the first mobile electrode; coupling elastic elements; anchorages attached to the substrate; elastic anchorage elements; a frame element, elastically coupled to said mass by the coupling elastic elements and coupled to the anchorages by the elastic anchorage elements, said coupling elastic elements and said anchorage elastic elements are configured to enable a first inertial movement of said mass in response to a first external acceleration in the first direction, and to enable a second inertial movement of said mass in response to a second external acceleration in a third direction transverse to said plane. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A MEMS device, comprising:
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a micromechanical structure that includes; a substrate; a mass suspended above the substrate and having a main extension in a plane, the plane including a first direction and a second direction, the main extension of the mass having a first opening separated from a second opening by a portion of the main extension that forms a mobile electrode, the first and second openings have a same length in the first direction, the mobile electrode also has the same length, a first width of the first opening being larger than a second width of the second opening, the first and second width both extend along the second direction; a first pair of fixed electrodes formed on the substrate, the first pair of fixed electrodes configured to extend into the first opening to interact with the mobile electrode, a portion of the substrate positioned below the second opening not including a fixed electrode; coupling elastic elements; anchorages attached to the substrate; elastic anchorage elements; a frame element, elastically coupled to said mass by the coupling elastic elements, and coupled to the anchorages by the anchorage elastic elements, said coupling elastic elements and said elastic anchorage elements are configured to enable a first inertial movement of said mass in response to a first external acceleration in the first direction, and to enable a second inertial movement of said mass in response to a second external acceleration in a third direction transverse to said plane; and an electronic reading circuit, electrically coupled to said micromechanical structure. - View Dependent Claims (15, 16, 17)
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18. An electronic device, comprising:
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a micromechanical structure that includes; a substrate; a mass which has a main extension in a plane and is suspended above said substrate, the plane having a first axis and a second axis that is transverse to the first axis, the mass including; a plurality of first openings, each first opening having a length that extends along the first axis, the plurality of first openings configured to form a first plurality of mobile electrodes; a plurality of second openings, each second opening having a same length that extends along the second axis, the plurality of second openings configured to form a second plurality of mobile electrodes, a first one of the second openings having a first width that is greater than a second width of a second one of the second openings, the first one being separated from the second one by one of the second plurality of mobile electrodes; a plurality of first pairs of fixed electrodes, each first pair configured to extend into one of the first openings, each electrode fixed to the substrate and configured to interact with one of the first plurality of mobile electrodes; a plurality of second pairs of fixed electrodes, each second pair configured to extend into one of the second openings, each electrode fixed to the substrate and configured to interact with one of the second plurality of mobile electrodes, a portion of the substrate below the second one of the second openings configured to not include any fixed electrodes; coupling elastic elements; anchorages; elastic anchorage elements, said coupling elastic elements and said anchorage elastic elements are configured to enable a first inertial movement of said mass in response to a first external acceleration about the first axis, and to enable a second inertial movement of said mass in response to a second external acceleration about a third axis transverse to said plane; an electronic reading circuit, electrically coupled to said micromechanical structure; and a digital processing unit coupled to the micromechanical structure. - View Dependent Claims (19, 20, 21)
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22. A device, comprising:
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a substrate; elastic coupling elements; a mass coupled to the substrate with the elastic coupling elements, the mass including; a plurality of first openings, each first opening having a length in a first direction and a first width in a second direction transverse to the first direction; a second opening having the same length in the first direction as the plurality of first openings and a second width in the second direction, the second width being smaller than the first width; a mobile electrode formed between one of the first openings and the second opening; and a plurality of pairs of fixed electrodes formed on the substrate, each pair extending into one of the first openings, a portion of the substrate below the second opening having no fixed electrodes, the mass including a centerline, the plurality of first opening and the second opening being on one side of the centerline and a plurality of third openings being positioned on another side of the centerline, each third opening having the length in the first direction and the first width in the second direction. - View Dependent Claims (23, 24)
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Specification