MULTI-AXIS CAPACITIVE ACCELEROMETER
First Claim
1. A multi-axis capacitive accelerometer, comprising:
- a substrate, having a plurality of sensing electrodes thereon;
a structure layer, suspended over the substrate, the structure layer comprises;
a plurality of anchor bases, fixed on the substrate;
a plurality of elastic structures, comprising at least a first set of elastic linkages, a second set of elastic linkages and a third set of elastic linkages;
a first proof mass, suspended over the substrate by the first set of elastic linkages and connected to the anchor bases for constraining the motion of the first proof mass either in a first direction or a second direction on a plane when sustaining an acceleration, wherein the first direction and the second direction are perpendicular to one another;
a second proof mass, suspended inside the first proof mass by the second set of elastic linkages for shifting in a direction perpendicular and coplanar with the shifting direction of the first proof mass;
a plurality of first fixed sensing blocks, disposed inside the first proof mass, wherein a first capacitive structure is formed between each first fixed sensing block and the corresponding first proof mass or second proof mass;
a third proof mass and a fourth proof mass, corresponding to the sensing electrodes on the substrate and being symmetrically disposed at two opposite sides of a central axis of the first proof mass, wherein the third proof mass and the fourth proof mass are asymmetrically suspended inside the second proof mass by the third set of elastic linkages and are provided with rotating axes along the first direction for achieving asymmetry in the second direction, and when the first proof mass sustains a force in a third direction perpendicular to the first direction the second direction, the third proof mass and the fourth proof mass rotate along the rotating axis; and
a plurality of second fixed sensing blocks, disposed inside the first proof mass, wherein each second fixed sensing block forms a second capacitive structure with the second proof mass.
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Accused Products
Abstract
A multi-axis accelerometer is consisted of a substrate with sensing electrodes and a structure layer. The structure layer includes anchor bases fixed on the substrate. A first proof mass is disposed over the substrate and has a first opening and a second opening symmetric to each other. The first proof mass is suspended to the anchor bases. Fixed sensing blocks are disposed on the substrate, and capacitors are formed between each fixed sensing block and the first proof mass for sensing acceleration along two in-plane directions. A second proof mass and a third proof mass are disposed in the first opening and the second opening and are asymmetrically suspended. Separate electrodes are disposed on the substrate and form two differential capacitors with the second proof mass and the third proof mass for sensing the out-of-plane acceleration.
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Citations
36 Claims
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1. A multi-axis capacitive accelerometer, comprising:
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a substrate, having a plurality of sensing electrodes thereon; a structure layer, suspended over the substrate, the structure layer comprises; a plurality of anchor bases, fixed on the substrate; a plurality of elastic structures, comprising at least a first set of elastic linkages, a second set of elastic linkages and a third set of elastic linkages; a first proof mass, suspended over the substrate by the first set of elastic linkages and connected to the anchor bases for constraining the motion of the first proof mass either in a first direction or a second direction on a plane when sustaining an acceleration, wherein the first direction and the second direction are perpendicular to one another; a second proof mass, suspended inside the first proof mass by the second set of elastic linkages for shifting in a direction perpendicular and coplanar with the shifting direction of the first proof mass; a plurality of first fixed sensing blocks, disposed inside the first proof mass, wherein a first capacitive structure is formed between each first fixed sensing block and the corresponding first proof mass or second proof mass; a third proof mass and a fourth proof mass, corresponding to the sensing electrodes on the substrate and being symmetrically disposed at two opposite sides of a central axis of the first proof mass, wherein the third proof mass and the fourth proof mass are asymmetrically suspended inside the second proof mass by the third set of elastic linkages and are provided with rotating axes along the first direction for achieving asymmetry in the second direction, and when the first proof mass sustains a force in a third direction perpendicular to the first direction the second direction, the third proof mass and the fourth proof mass rotate along the rotating axis; and a plurality of second fixed sensing blocks, disposed inside the first proof mass, wherein each second fixed sensing block forms a second capacitive structure with the second proof mass. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A multi-axis capacitive accelerometer, comprising:
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a substrate, having at least two sensing electrodes disposed on a surface thereof; a structure layer, comprising; a plurality of anchor bases, fixed on the surface of the substrate; a first proof mass, suspended over the surface of the substrate and provided with a central axis, the first proof mass further having a first opening and a second opening both located inside the first proof mass and symmetrically disposed at two opposite sides of the central axis; a first set of elastic linkages, connecting the anchor base and the first proof mass; a plurality of fixed sensing blocks, adjacent to the first proof mass and situated on the surface of the substrate, wherein a capacitive structure is formed between each of the fixed sensing blocks and the first proof mass; a second proof mass and a third proof mass, respectively located inside the first opening and the second opening, and suspended over the sensing electrodes of the substrate to form a sensing capacitance; and a second set of elastic linkages and a third set of elastic linkages, respectively connected between the second proof mass and the first proof mass and between the third proof mass and the first proof mass for asymmetrically suspending the second proof mass and the third proof mass in the first opening and the second opening, the second proof mass and the third proof mass rotating along axes parallel to an X-axis respectively when sustaining an acceleration along a Z-axis, wherein the rotating axis of the second proof mass and the rotating axis of the third proof mass are symmetrically disposed at two opposite sides of the central axis of the first proof mass. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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Specification