Micromechanical resonating devices and related methods
Micromechanical resonating devices, as well as related methods, are described herein. The resonating devices can include a micromechanical resonating structure, an actuation structure that actuates the resonating structure, and a detection structure that detects motion of the resonating structure.
1. A micromechanical device comprising:
a mechanical resonating structure;
an actuation structure constructed and arranged to actuate the resonating structure; and
a detection structure constructed and arranged to detect motion of the resonating structure,
wherein an actuation gap is defined between a first portion of the resonating structure and a portion of the actuation structure, and a detection gap is defined between a second portion of the resonating structure and a portion of the detection structure,
wherein at least one of the actuation structure and the detection structure is constructed and arranged to move relative to the resonating structure to respectively tune the actuation gap and/or the detection gap.
2. The device of claim 1 , wherein the actuation structure is constructed and arranged to move relative to the resonating structure to tune the actuation gap and the detection structure is constructed and arranged to move relative to the resonating structure to tune the detection gap.
3. The device of claim 1 , further comprising at least one motion limiting element designed to limit the motion of the actuation structure and/or detection structure relative to the resonating structure.
4. The device of claim 1 , wherein the actuation structure is moved by applying a bias to the actuation structure and/or the detection structure is moved by applying a bias to the detection structure.
5. The device of claim 4 , wherein the actuation structure and/or detection structure includes a fixed portion and a suspended portion, and the applied bias moves the suspended portion relative to the fixed portion and relative to the resonating structure.
6. The device of claim 1 , wherein the actuation and/or detection structure comprises a comb structure.
7. The device of claim 1 , wherein the actuation gap is defined between a conductive portion of the actuation structure and a conductive portion of the resonating structure, and the detection gap is defined between a conductive portion of the detection structure and a conductive portion of the resonating structure.
8. The device of claim 7 , wherein the conductive portion of the actuation structure is part of a suspended portion of the actuation structure.
9. The device of claim 7 , wherein the conductive portion of the detection structure is part of a suspended portion of the detection structure.
10. The device of claim 7 , wherein the conductive portion of the resonating structure is the first portion of the resonating structure.
11. The device of claim 7 , wherein the conductive portion of the resonating structure is the second portion of the resonating structure.
12. The device of claim 1 , wherein the actuation structure actuates the resonating structure when the capacitance between the actuation structure and the resonating structure is changed.
13. The device of claim 1 , wherein the detection structure detects motion of the resonating structure when the capacitance between the detection structure and the resonating structure is changed.
14. The device of claim 1 , wherein the resonating structure resonates primarily in a plane substantially perpendicular to the actuation gap and/or detection gap.
15. The device of claim 1 , wherein the actuation gap and/or detection gap is substantially constant when the resonating structure resonates.
16. The device of claim 1 , wherein the resonating structure comprises major elements and minor elements.
17. The device of claim 16 , wherein the major elements have a large dimension between 1 micron and 100 micron and the minor elements have a large dimension between 0.1 micron and 10 micron.
18. The device of claim 1 , wherein the detection structure is the same structure as the actuation structure.
19. A micromechanical device comprising:
a mechanical resonating structure including a suspended resonating portion defined between a first end and a second end;
an actuation structure constructed and arranged to actuate the resonating structure, the actuation structure including a suspended actuation portion defined between a third end and a fourth end; and
a detection structure constructed and arranged to detect motion of the resonating structure, the detection structure including a suspended detection portion defined between a fifth and a sixth end.
20. The device of claim 19 , wherein an actuation gap is defined between the suspending resonating portion and the suspended actuation portion, and a detection gap is defined between the suspended resonating portion and the suspended detection portion.
21. The device of claim 20 , wherein the actuation structure and the detection structure are constructed and arranged to move relative to the resonating structure to respectively tune the actuation gap and/or detection gap.
22. The device of claim 19 , wherein the actuation structure actuates the resonating structure when the capacitance between the actuation structure and the resonating structure is changed and the detection structure detects motion of the resonating structure when the capacitance between the detection structure and the resonating structure is changed.
23. A micromechanical device comprising:
a capacitive structure comprising a suspended first portion and a suspended second portion separated from the first portion by a distance, wherein at least one of the first portion and the second portion is designed to actuate in response to an applied bias to change the distance; and
a mechanical resonating structure located, at least in part, between the first portion and the second portion.
24. A timing oscillator comprising:
a mechanical resonating structure including a major element and a minor element coupled to the major element;
a drive circuit designed to provide an input signal to the mechanical resonating structure;
a compensation circuit coupled to the mechanical resonating structure;
an actuation structure constructed and arranged to actuate the mechanical resonating structure; and
a detection structure constructed and arranged to detect motion of the mechanical resonating structure,
wherein an actuation gap is defined between a portion of the mechanical resonating structure and a portion of the actuation structure, and a detection gap is defined between a portion of the mechanical resonating structure and a portion of the detection structure,
wherein at least one of the actuation structure and the detection structure is constructed and arranged to move relative to the mechanical resonating structure to respectively tune the actuation gap and/or the detection gap.
25. The timing oscillator of claim 24 , wherein the drive circuit comprises a gap-tuning circuit to tune the actuation gap and/or the detection gap.
26. The timing oscillator of claim 24 , wherein the detection structure is coupled to the compensation circuit to provide feedback to the compensation circuit.
27. The timing oscillator of claim 24 , wherein the detection structure is coupled to the drive circuit to provide feedback to the drive circuit.
28. The timing oscillator of claim 27 , wherein the detection structure provides the feedback to modify a frequency of the resonating structure.
29. A method of operating a micromechanical device comprising:
providing a micromechanical device including:
a mechanical resonating structure;
an actuation structure constructed and arranged to actuate the resonating structure; and
a detection structure constructed and arranged to detect motion of the resonating structure,
wherein an actuation gap is defined between a portion of the resonating structure and a portion of the actuation structure, and a detection gap is defined between a portion of the resonating structure and a portion of the detection structure;
moving the actuation structure and/or the detection structure relative to the resonating structure to respectively tune the actuation gap and/or detection gap; and
actuating the resonating structure.
30. The method of claim 29 , comprising applying a bias to move the actuation structure relative to the resonating structure to tune the actuation gap.
31. The method of claim 29 , comprising applying a bias to move the detection structure relative to the resonating structure to tune the detection gap.
32. The method of claim 29 , wherein the resonating structure is actuated when the capacitance between the actuation structure and the resonating structure is changed.