Microelectromechanical resonator structure, and method of designing, operating and using same

• US 7,205,867 B2
• Filed: 05/19/2005
• Issued: 04/17/2007
• Est. Priority Date: 05/19/2005
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Partridge, Aaron, Lutz, Markus
• Primary Examiner(s): Summons; Barbara
• Application Number:
  US11/132,941
• Publication Number:
  US 20060261915A1
• Time in Patent Office: 698 Days
• Field of Search: 333/186
• US Class Current: 333/186
• CPC Class Codes: H03H 2009/02354 applied along the periphery, e.g. at nodal points of the ring
• CPC Class Codes: H03H 2009/02496 Horizontal, i.e. parallel to the substrate plane
• CPC Class Codes: H03H 2009/02503 Breath-like, e.g. Lam? mode, wine-glass mode
• CPC Class Codes: H03H 2009/02511 Vertical, i.e. perpendicular to the substrate plane
• CPC Class Codes: H03H 2009/02527 Combined
• CPC Class Codes: H03H 9/02259 Driving or detection means
• CPC Class Codes: H03H 9/02338 Suspension means
• CPC Class Codes: H03H 9/02448 of temperature influence
• CPC Class Codes: H03H 9/2405 of microelectro-mechanical resonators
• CPC Class Codes: H03H 9/2431 Ring resonators

Abstract

A micromechanical resonator structure including a plurality of straight or substantially straight beam sections that are connected by curved or rounded sections. Each elongated beam section is connected to another elongated beam section at a distal end via the curved or rounded sections thereby forming a geometric shape having at least two elongated beam sections that are interconnected via curved or rounded sections (for example, a rounded triangle shape, rounded square or rectangle shape). The structure includes one or more nodal points or areas (i.e., portions of the resonator structure that are stationary, experience little movement, and/or are substantially stationary during oscillation of the resonator structure) in one or more portions or areas of the curved sections of the structure. The nodal points are suitable and/or preferable locations to anchor the resonator structure to the substrate. In operation, the resonator structure oscillates in a combined elongating (or breathing) mode and bending mode; that is, the beam sections (which oscillate or vibrate at the same frequency) exhibit an elongating-like (or breathing-like) motion and a bending-like motion.

Claims

1. A microelectromechanical resonator structure comprising:

a plurality of elongated straight beam sections wherein each beam section includes a first end and a second end;

a plurality of curved sections, wherein each curved section includes a first end and a second end, and wherein at least one curved section includes a nodal point;

wherein each end of a beam section is connected to an associated end of one of the curved section to thereby form a geometric shape;

at least one anchor coupling section; and

a substrate anchor, coupled to the nodal point via the anchor coupling section, to secure the resonator structure to a substrate.

2. The microelectromechanical resonator structure of claim 1 further including a stress/strain relief mechanism coupled between the substrate anchor and the nodal point.

3. The microelectromechanical resonator structure of claim 1 wherein:

the plurality of elongated straight beam sections include first, second and third elongated straight beam sections;

the plurality of curved sections include first, second and third elongated curved sections; and

wherein the geometric shape is a rounded triangle shape.

4. The microelectromechanical resonator structure of claim 1 wherein:

the plurality of elongated straight beam sections include first, second, third and fourth elongated straight beam sections;

the plurality of curved sections include first, second, third and fourth elongated curved sections; and

wherein the geometric shape is a rounded rectangle shape.

5. The microelectromechanical resonator structure of claim 1 wherein:

the plurality of elongated straight beam sections include first, second, third and fourth elongated straight beam sections;

the plurality of curved sections include first, second, third and fourth elongated curved sections; and

wherein the geometric shape is a rounded square shape.

6. The microelectromechanical resonator structure of claim 5 wherein each curved section includes at least one nodal point.

7. The microelectromechanical resonator structure of claim 6 wherein the substrate anchor is coupled to the at least one nodal point of each curved section.

8. The microelectromechanical resonator structure of claim 7 further including a plurality of stress/strain relief mechanisms coupled between the substrate anchor and each nodal point of the at least one nodal point of each curved section.

9. The microelectromechanical resonator structure of claim 6 wherein the substrate anchor includes a plurality of anchors and wherein the at least one nodal point of each curved section is coupled to at least one of the plurality of anchors to secure the resonator structure to a substrate.

10. The microelectromechanical resonator structure of claim 9 further including a plurality of stress/strain relief mechanisms coupled between each anchor and the at least one nodal point of each curved section.

11. The microelectromechanical resonator structure of claim 1 wherein one of the plurality of elongated straight beam sections includes a plurality of slots disposed therein.

12. The microelectromechanical resonator structure of claim 1 wherein one of the plurality of curved sections includes a plurality of slots disposed therein.

13. The microelectromechanical resonator structure of claim 1 wherein the width of each elongated straight beam sections of the plurality of elongated straight beam sections is greater at the ends than in the center thereof.

14. The microelectromechanical resonator structure of claim 1 wherein the plurality of elongated straight beam sections are filleted at the ends thereof.

15. A microelectromechanical resonator structure comprising:

a plurality of elongated straight beam sections wherein each beam section includes a first end and a second end;

a plurality of curved sections, wherein each curved section includes a first end and a second end, and wherein each curved section includes a nodal point;

wherein each end of a beam section is connected to an associated end of one of the curved sections to thereby form a geometric shape;

a plurality of anchor coupling sections; and

a substrate anchor, coupled to the nodal points of each curved section via the plurality of anchor coupling sections, to secure the resonator structure to a substrate.

16. The microelectromechanical resonator structure of claim 15 further including a plurality of stress/strain relief mechanisms, wherein each stress/strain relief mechanism is coupled between the substrate anchor and an associated nodal point.

17. The microelectromechanical resonator structure of claim 15 wherein:

the plurality of elongated straight beam sections include first, second, third and fourth elongated straight beam sections;

the plurality of curved sections include first, second, third and fourth elongated curved sections; and

wherein the geometric shape is a rounded square shape.

18. The microelectromechanical resonator structure of claim 15 wherein the substrate anchor includes a plurality of anchors and wherein the at least one nodal point of each curved section is coupled to at least one of the plurality of anchors to secure the resonator structure to a substrate.

19. The microelectromechanical resonator structure of claim 18 further including a plurality of stress/strain relief mechanisms coupled between an associated anchor of the plurality of anchors and an associated nodal point of the at least one nodal point of each curved section.

20. The microelectromechanical resonator structure of claim 18 wherein the nodal point of each curved section is located on an inner portion of the curved section.

21. The microelectromechanical resonator structure of claim 18 wherein the nodal point of each curved section is located on an outer portion of the curved section.

22. The microelectromechanical resonator structure of claim 15 wherein the plurality of elongated straight beam sections includes a plurality of slots disposed therein.

23. The microelectromechanical resonator structure of claim 15 wherein the plurality of curved sections includes a plurality of slots disposed therein.

24. A microelectromechanical resonator structure comprising:

a plurality of elongated straight beam sections wherein each beam section includes a first end and a second end;

a plurality of curved sections, wherein each curved section includes a first end and a second end, and wherein each curved section includes at least one nodal point;

wherein each end of a beam section is connected to an associated end of one of the curved sections to thereby form a geometric shape;

a substrate anchor, coupled to at least one nodal point of each curved section, to secure the resonator structure to a substrate;

a plurality of sense electrodes;

a plurality of drive electrodes, wherein the sense and drive electrodes are juxtaposed the plurality of elongated straight beam sections; and

sense circuitry, coupled to the sense electrodes, to provide an output signal.

25. The microelectromechanical resonator structure of claim 24 wherein the sense electrodes provide one or more signals to the sense circuitry which, in response, provides a differential output signal.

26. The microelectromechanical resonator structure of claim 25 further including a plurality of stress/strain relief mechanisms, wherein each stress/strain relief mechanism is coupled between the substrate anchor and an associated nodal point.

27. The microelectromechanical resonator structure of claim 25 wherein the plurality of curved sections includes a plurality of slots disposed therein.

28. The microelectromechanical resonator structure of claim 25 wherein:

the plurality of elongated straight beam sections include first, second, third and fourth elongated straight beam sections;

the plurality of curved sections include first, second, third and fourth elongated curved sections; and

wherein the geometric shape is a rounded square shape.

29. The microelectromechanical resonator structure of claim 28 wherein the substrate anchor is disposed within the rounded square shape of the microelectromechanical resonator structure.

30. The microelectromechanical resonator structure of claim 28 wherein the substrate anchor includes a plurality of anchors and wherein the at least one nodal point of each curved section is coupled to at least one of the plurality of anchors to secure the resonator structure to a substrate.

31. The microelectromechanical resonator structure of claim 30 further including a plurality of stress/strain relief mechanisms coupled between an associated anchor of the plurality of anchors and an associated nodal point of the at least one nodal point of each curved section.

32. The microelectromechanical resonator structure of claim 30 wherein the nodal point of each curved section is located on an inner portion of the curved section.

33. The microelectromechanical resonator structure of claim 30 wherein the nodal point of each curved section is located on an outer portion of the curved section.

34. The microelectromechanical resonator structure of claim 25 wherein the plurality of elongated straight beam sections includes a plurality of slots disposed therein.

35. The microelectromechanical resonator structure of claim 24 wherein the sense electrodes provide one or more signals to the sense circuitry which, in response, provides a single ended output signal.