MEMS device with improved spring system
A system and method in accordance with an embodiment reduces the cross-axis sensitivity of a gyroscope. This is achieved by building a gyroscope using a mechanical transducer that comprises a spring system that is less sensitive to fabrication imperfection and optimized to minimize the response to the rotations other than the intended input rotation axis. The longitudinal axes of the first and second flexible elements are parallel to each other and parallel to the first direction.
1. A microelectromechanical system (MEMS) device comprising:
a proof mass system that includes a proof mass, the proof mass moves in a first direction in a plane in response to a force, and wherein the proof mass moves in the plane; and
a spring system comprising a first flexible element, a first rigid lever arm, a second rigid lever arm and a second flexible element, wherein the first flexible element, the first rigid lever arm, the second rigid lever arm and the second flexible element are disposed in the plane,
the first rigid lever arm being connected to the first flexible element, the second rigid lever arm being connected to the second flexible element, and the first flexible element and the second flexible element being connected to one another via an intervening support anchor distinct from the proof mass, and wherein the first flexible element and the second flexible element each have a longitudinal axis parallel to the first direction of motion and wherein when the proof mass moves in the first direction, the first flexible element and the second flexible element bend in the plane, and the first and second rigid lever arms rotate in the plane.
2. The MEMS device of claim 1 , wherein the proof mass system comprises a transducer, wherein the transducer senses motion of the proof mass.
3. The MEMS device of claim 1 , wherein the force is in response to gravity.
4. The MEMS device of claim 1 , wherein the force is in response to acceleration of the MEMS device.
5. The MEMS device of claim 1 , wherein the force is in response to a magnetic field.
6. The MEMS device of claim 1 , wherein the force is a Coriolis force in response to angular velocity.
7. The MEMS device of claim 1 , wherein the force is an electrostatic force.
8. The MEMS device of claim 1 , further comprising third and fourth flexible elements, wherein the third flexible element connects the first rigid lever arm to the proof mass, wherein the fourth flexible element connects the second rigid lever arm to the proof mass, and wherein the third flexible element and the fourth flexible element each has a longitudinal axis parallel to the first direction of motion.
9. The MEMS device of claim 8 , wherein the first flexible element and the third flexible element each has a midpoint aligned along an axis perpendicular to the first direction of motion and the second flexible element and the fourth flexible element each has a midpoint aligned along an axis perpendicular to the first direction of motion.
10. A microelectromechanical system (MEMS) device comprising:
a proof mass;
a spring system compliant in a first direction of motion and coupled to the proof mass, the spring system comprising a first flexible element; and
a first rigid lever arm coupled to the first flexible element, a second rigid lever arm coupled to a second flexible element, and the first flexible element and the second flexible element being coupled to one another via an intervening support anchor distinct from the proof mass, wherein the first flexible element and the second flexible element each have a longitudinal axis parallel to the first direction of motion, wherein the proof mass and the spring system are disposed in a plane, and wherein the proof mass moves in the first direction of motion in the plane in response to a force.