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US 12,503,358 B2Granted
Anchor design with rejection of external shear force
AssigneeInvenSense, Inc.
InventorsMrigank Sharma, Varun Subramaniam Kumar, Luca Coronato, Giacomo Laghi, Matthew Julian Thompson
Life of this patent
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Abstract
A MEMS sensor includes at least one anchor that extends into a MEMS layer and a proof mass suspended from the at least one anchor. Each anchor is coupled to the proof mass via two compliant springs that are oriented perpendicular to each other and attached to a respective anchor. The compliant springs absorb non-measured external forces such as shear forces that are applied to the sensor packaging, preventing these forces from modifying the relative location and operation of the proof mass.
Claims20
A microelectromechanical system (MEMS) sensor, comprising:
- at least one anchor that extends into a MEMS layer;
- and
- a suspended spring-mass system located in the MEMS layer that extends along a first direction and a second direction and comprises a proof mass and a coupling mass connected to the proof mass, the proof mass configured to move in a third direction in response to an external excitation, wherein the first direction, second direction, and third direction are orthogonal to each other, the proof mass extending along the first and second directions in an initial orientation when at rest, and the at least one anchor displaceable from an initial position at rest to a tilted position in response to a shear force applied to the MEMS sensor in a plane defined by the first and second directions;
- a first compliant spring connected between the at least one anchor and the coupling mass, wherein the first compliant spring is configured to rotate about a first axis extending in the first direction in response to a first component of the shear force along the second direction and maintain the proof mass in the initial orientation when the first component of the shear force is applied to the MEMS sensor;
- a second compliant spring connected between the at least one anchor and the coupling mass, wherein the second compliant spring is configured to rotate about a second axis extending in the second direction in response to a second component of the shear force along the first direction and maintain the proof mass in the initial orientation when the second component of the shear force is applied to the MEMS sensor, and
- a first stiffening spring extending along the first direction parallel to the first axis;
- and
- a second stiffening spring extending along the second direction parallel to the second axis, wherein
- the first stiffening spring and the second stiffening spring connect the proof mass to the coupling mass.
6 more elements
A microelectromechanical system (MEMS) sensor, comprising:
- at least one anchor that extends into a MEMS layer, wherein the at least one anchor comprises a first anchor, a second anchor, a third anchor, and a fourth anchor;
- a suspended spring-mass system located in the MEMS layer that extends along a first direction and a second direction and comprises a proof mass and a coupling mass connected to the proof mass, the proof mass configured to move in a third direction in response to an external excitation, wherein the first direction, second direction, and third direction are orthogonal to each other, the proof mass extending along the first and second directions in an initial orientation when at rest, and the first, second, third, and fourth anchors each displaceable from an initial position when at rest to a tilted position in response to a shear force applied to the MEMS sensor in a plane defined by the first and second directions;
- a first compliant spring connected between the first anchor and the coupling mass, wherein the first compliant spring is configured to rotate about a first axis extending in the first direction in response to a component of the shear force along the second direction;
- a second compliant spring connected between the first anchor and the coupling mass, wherein the second compliant spring is configured to rotate about a second axis extending in the second direction in response to a component of the shear force along the first direction;
- a third compliant spring connected between the second anchor and the coupling mass, wherein the third compliant spring is configured to rotate about a third axis extending in the first direction in response to the component of the shear force along the second direction;
- a fourth compliant spring connected between the second anchor and the coupling mass, wherein the fourth compliant spring is configured to rotate about a fourth axis extending in the second direction in response to the component of the shear force along the first direction;
- a fifth compliant spring connected between the third anchor and the coupling mass, wherein the fifth compliant spring is configured to rotate about a fifth axis extending in the first direction in response to the component of the shear force along the second direction;
- a sixth compliant spring connected between the third anchor and the coupling mass, wherein the sixth compliant spring is configured to rotate about a sixth axis extending in the second direction in response to a-the component of the shear force along the first direction;
- a seventh compliant spring connected between the fourth anchor and the coupling mass, wherein the seventh compliant spring is configured to rotate about a seventh axis extending in the first direction in response to the component of the shear force along the second direction;
- an eighth compliant spring connected between the fourth anchor and the coupling mass, wherein the eighth compliant spring is configured to rotate about an eighth axis extending in first axis extending in the second direction in response to the component of the shear force along the first direction;
- a first stiffening spring extending along the first direction parallel to the first axis;
- a second stiffening spring extending along the second direction parallel to the second axis;
- a third stiffening spring extending along the first direction parallel to the first axis;
- a fourth stiffening spring extending along the second direction parallel to the second axis;
- a fifth stiffening spring extending along the first direction parallel to the first axis;
- a sixth stiffening spring extending along the second direction parallel to the second axis;
- a seventh stiffening spring extending along the first direction parallel to the first axis;
- and
- an eighth stiffening spring extending along the second direction parallel to the second axis;
- wherein
- the first stiffening spring, the second stiffening spring, the third stiffening spring, the fourth stiffening spring, the fifth stiffening spring, the sixth stiffening spring, the seventh stiffening spring, and the eighth stiffening spring connect the proof mass to the coupling mass;
- wherein the first, third, fifth, and seventh compliant springs and maintain the proof mass in the initial orientation when the second component of the shear force is applied to the MEMS sensor and the second, fourth, sixth, and eighth compliant springs maintain the proof mass in the initial orientation when the second component of the shear force is applied to the MEMS sensor.
19 more elements
A microelectromechanical system (MEMS) sensor, comprising:
- at least one anchor that extends into a MEMS layer;
- a suspended spring-mass system located in the MEMS layer comprising a proof mass, wherein the proof mass comprises an upper plane and a lower plane parallel to the upper plane, and wherein each of the upper plane and the lower plane extend along a respective first direction and a respective second direction in an initial orientation when at rest, and the at least one anchor displaceable from an initial position when at rest to a tilted position in response to a shear force applied to the MEMS sensor in a plane defined by the first and second directions;
- a first compliant spring connected between the at least one anchor and the proof mass, wherein the first compliant spring is configured to rotate about an axis extending in the first direction in response to a first component of the shear force along the second direction and maintain the proof mass in the initial orientation when the first component of the shear force is applied to the MEMS sensor;
- a second compliant spring connected between the at least one anchor and the proof mass, wherein the second compliant spring is configured to rotate about an axis extending in the second direction in response to a second component of the shear force along the first direction and maintain the proof mass in the initial orientation when the second component of the shear force is applied to the MEMS sensor, and wherein the first compliant spring and the second compliant spring are each located at 20%-80% of the length of a respective anchor side from a first corner of the at least one anchor, and
- a first stiffening spring extending along the first direction parallel to the first axis;
- and
- a second stiffening spring extending along the second direction parallel to the second axis, wherein
- the first stiffening spring and the second stiffening spring connect the proof mass to the coupling mass.
5 more elements
Dependencies are inferred from the claim text.