Micromechanical rotational speed sensor

• US 8,342,022 B2
• Filed: 03/12/2007
• Issued: 01/01/2013
• Est. Priority Date: 03/10/2006
• Status: Active Grant

• Current Assignee: Conti Temic Microelectronic GmbH (Continental AG)
• Original Assignee: Conti Temic Microelectronic GmbH (Continental AG)
• Inventors: Schmid, Bernhard, Guenthner, Stefan
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US12/225,009
• Publication Number:
  US 20090031806A1
• Time in Patent Office: 2,122 Days
• Field of Search: 735/041.2, 735/040.4, 735/041.4
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5747 each sensing mass being connected to a driving mass, e.g. driving frames
• CPC Class Codes: G01C 19/5762 the sensing mass being connected to a driving mass, e.g. driving frames

Abstract

A micromechanical rotational rate sensor includes a substrate, at least one base element suspended by at least one spring element on the substrate, an excitation device and a read-out arrangement. The base element includes at least one seismic or inertial mass. The spring element is movable perpendicularly to the motion direction of the base element so that apex or deflection points of the spring element will move perpendicularly to the excitation direction while the base element is thereby not excited to move perpendicularly to the excitation direction.

Claims

1. A micromechanical rotation rate sensor comprising:

a substrate;

a base element that comprises an inertial mass;

plural spring elements that movably connect and suspend said base element relative to said substrate;

an excitation arrangement that is arranged and cooperates with said base element so as to be adapted to excite said base element into oscillation in an oscillation direction in an oscillation plane; and

a read-out arrangement that is arranged and cooperates with said base element so as to be adapted to sense a motion of said base element in at least one sensing direction perpendicular to said oscillation direction;

wherein each one of said spring elements has at least one bend respectively at at least one vertex point; and

wherein said spring elements are so configured and arranged such that in connection with said oscillation of said base element in said oscillation direction in said oscillation plane said at least one bend deflects perpendicularly to said oscillation plane while said base element is not excited to deflect perpendicularly to said oscillation plane.

2. The micromechanical rotation rate sensor according to claim 1, wherein each one of said spring elements respectively comprises at least two spring legs connected to one another successively at a respective said bend.

3. The micromechanical rotation rate sensor according to claim 2, wherein said spring legs are connected to one another in a U-shaped configuration.

4. The micromechanical rotation rate sensor according to claim 2, wherein said spring legs are connected to one another in a V-shaped configuration.

5. The micromechanical rotation rate sensor according to claim 2, wherein said spring legs are connected to one another in an S-shaped configuration.

6. The micromechanical rotation rate sensor according to claim 1, wherein said base element further comprises a frame and at least one suspension element that movably suspends said inertial mass on said frame.

7. The micromechanical rotation rate sensor according to claim 1, wherein said plural spring elements comprise four spring elements.

8. The micromechanical rotation rate sensor according to claim 7, wherein said spring elements are arranged mirror symmetrically on said base element.

9. The micromechanical rotation rate sensor according to claim 1, further comprising a second base element, plural second spring elements that movably suspend said second base element relative to said substrate, a coupling spring and at least two further spring elements, wherein said base element and said second base element are arranged adjacent one another with said coupling spring element therebetween, and said further spring elements respectively movably connect said base element and said second base element to said coupling spring, whereby said base element and said second base element are coupled to one another through said further spring elements and said coupling spring.

10. The micromechanical rotation rate sensor according to claim 9, wherein said further spring elements are not connected to said substrate.

11. The micromechanical rotation rate sensor according to claim 1, configured, arranged and adapted to sense rotational motions of said micromechanical rotation rate sensor about a rotational axis perpendicular to said oscillation direction and lying in said oscillation plane.

12. The micromechanical rotation rate sensor according to claim 1, configured, arranged and adapted to sense rotational motions of said micromechanical rotation rate sensor about a rotation axis perpendicular to said oscillation plane.

13. The micromechanical rotation rate sensor according to claim 1, configured, arranged and adapted to sense rotational motions of said micromechanical rotation rate sensor respectively about two orthogonal rotation axes that are both perpendicular to said oscillation direction.

14. The micromechanical rotation rate sensor according to claim 1, wherein each respective one of said spring elements is respectively connected to said base element at a respective first connection and is respectively connected to said substrate at a respective second connection, said respective first connection is aligned with said respective second connection along a respective spring connection axis of said respective spring element when said base element is stationary or in a neutral position of said oscillation, said respective spring element comprises plural spring legs respectively connected to one another in succession by said at least one bend, and all of said spring legs and said at least one bend extend along and are confined to only one half-plane having a bounding edge along said respective spring connection axis and extending radially on only one side of said respective spring connection axis.

15. The micromechanical rotation rate sensor according to claim 1, wherein each respective one of said spring elements is respectively connected to said base element at a respective corner of said base element on a side of said base element extending parallel to said oscillation direction, and said respective spring element does not extend outwardly beyond said respective corner of said base element in said oscillation direction.

16. The micromechanical rotation rate sensor according to claim 1, wherein each respective one of said spring elements respectively comprises two spring legs and a vertex leg that interconnects said two spring legs and forms said bend at said vertex point, wherein side surfaces of said spring legs extend at a non-zero acute tilt angle relative to a perpendicular to said oscillation plane, and wherein said vertex leg extends longitudinally at a non-zero acute slope angle relative to said oscillation plane when said bend deflects in a direction perpendicular to said oscillation plane.

17. The micromechanical rotation rate sensor according to claim 1, wherein each respective one of said spring elements respectively includes a spring leg that extends along a side edge of said base element and that is connected directly to a mounting stud of said base element without any further spring portion interposed between said spring leg and said mounting stud, and wherein said mounting stud is thicker and less flexible than said spring leg.

18. A micromechanical rotation rate sensor comprising:

a substrate;

a base element that comprises an inertial mass and that is bounded by two opposite side edges;

four spring elements that movably connect and suspend said base element relative to said substrate;

an excitation arrangement that is arranged and cooperates with said base element so as to be adapted to excite said base element into oscillation in an oscillation direction parallel to said side edges along a major plane of said base element;

a read-out arrangement that is arranged and cooperates with said base element so as to be adapted to sense a motion of said base element in at least one sensing direction perpendicular to said oscillation direction;

four substrate mounting protrusions that protrude from said substrate toward said base element in a transverse direction perpendicular to said oscillation direction and said side edges; and

four base mounting protrusions that protrude from said side edges of said base element toward respective ones of said substrate mounting protrusions in said transverse direction;

wherein each respective one of said spring elements comprises a first spring leg extending parallel to said side edges and having a proximal end thereof connected directly to one of said substrate mounting protrusions, a second spring leg extending parallel to said side edges and having a proximal end thereof connected directly to one of said base mounting protrusions, and a junction piece that joins a distal end of said first spring leg with a distal end of said second spring leg,

wherein a width of said substrate mounting protrusions and a width of said base mounting protrusions respectively in said major plane and parallel to said side edges is respectively greater than a width of said first spring leg and a width of said second spring leg respectively in said major plane and perpendicular to said side edges,

wherein a width of each said junction piece in said major plane and parallel to said side edges is respectively greater than said width of said first spring leg and said width of said second spring leg, and

wherein a length of said substrate mounting protrusions and a length of said base mounting protrusions respectively in said major plane and perpendicular to said side edges is respectively less than a length of said first spring leg and a length of said second spring leg respectively in said major plane and parallel to said side edges.