Micro accelermoter

• US 20050274185A1
• Filed: 10/28/2004
• Published: 12/15/2005
• Est. Priority Date: 06/10/2004
• Status: Active Grant

• Current Assignee: National Chung-Shan Institute of Science and Technology, Neostones Microfabrication Corporation
• Original Assignee: Chung-Shan Institute of Science & Technology Armaments Bureau MND (Government of The Republic of China), Neostones Microfabrication Corporation
• Inventors: Tsai, Deng-Horng, Ho, Kye-Chyn, Lo, Yuan, Lin, Lung-Yung, Sche, Schiu
• Granted Patent: US 7,210,351 B2
• Time in Patent Office: Days
• US Class Current: 73/514.10
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 15/18 in two or more dimensions
• CPC Class Codes: G01P 2015/082 for two degrees of freedom of movement of a single mass

Abstract

A micro accelerometer including a plurality of proof masses is provided to detect the acceleration of the first axis, the second axis and the third axis. The disclosed micro accelerometer has the advantages of close loop control, mechanical decoupling, and not relying on high aspect ratio manufacturing technology.

Claims

1. A micro accelerometer comprising:

a first proof mass;

a second proof mass and a third proof mass arranged at each of the two opposite sides of the first proof mass connected to the first proof mass by two flexible supporters and having a plurality of slots formed thereon, wherein the second proof mass and the third proof mass move along a first axial direction parallel to the first proof mass; and

a plurality of electrode plate sets arranged relative to the second proof mass and the third proof mass respectively, for forming a plurality of sets of sensing electrodes of the first axial direction together with the second proof mass and the third proof mass, wherein the sensing electrodes are configured in differential circuits.

2. The micro accelerometer of claim 1, wherein the first proof mass comprises:

a frame;

an upper electrode plate; and

a plurality of flexible supporters connecting the frame and the upper electrode plate.

3. The micro accelerometer of claim 2, wherein the upper electrode plate further comprises a plurality of holes formed thereon.

4. The micro accelerometer of claim 1, wherein each set of electrode plates further comprises two sets of electrode plates interleaved with each other and parallel to the slots such that each of the slots covers portion of the electrode plates, where the two sets of electrode plates are configured in differential circuits.

5. The micro accelerometer of claim 1, wherein the proof masses are supported by a plurality of supporting anchors, where each of the supporting anchors is connected to each of the proof mass though a flexible supporter.

6. The micro accelerometer of claim 1, wherein the second proof mass and the third proof mass are arranged with a close loop control electrode respectively for controlling second proof mass and the third proof mass to move back to the original position when the second proof mass and the third proof mass generate displacement caused by an acceleration.

7. The micro accelerometer of claim 6, wherein the control electrode is rectangular electrode plate, which is arranged at the exterior side of the second proof mass and the third proof mass respectively.

8. The micro accelerometer of claim 6, wherein the control electrode comprises a electrode arranged between the two flexible supporters of the first proof mass.

9. The micro accelerometer of claim 6, wherein the control electrode comprises:

a first comb-like electrode, connected to the respective proof mass; and

a second comb-like electrode arranged to interleave with the first comb-like electrode.

10. A micro accelerometer comprising:

a first proof mass moving in the axial direction vertical to the first proof mass;

a second proof mass and a third proof mass arranged at each of the two opposite sides of the first proof mass, connected to the first proof mass by two flexible supporters and having a plurality of slots formed thereon, wherein the second proof mass and the third proof mass move along a first axial direction parallel to the first proof mass;

a lower electrode arranged relative to the first proof mass for forming a sensing capacitor together with the first proof mass; and

a plurality of electrode plate sets arranged relative to the second proof mass and the third proof mass respectively, for forming a plurality of sets of sensing electrodes of the first axial direction together with the second proof mass and the third proof mass, wherein the sensing electrodes are configured in differential circuits.

11. The micro accelerometer of claim 10, wherein the first proof mass comprises:

a frame;

an upper electrode plate; and

a plurality of flexible supporters connecting the frame and the upper electrode plate.

12. The micro accelerometer of claim 11, wherein the upper electrode plate further comprises a plurality of holes formed thereon.

13. The micro accelerometer of claim 10, wherein each set of electrode plates further comprises two sets of electrode plates interleaved with each other and parallel to the slots such that each of the slots covers portion of the electrode plates, where the two sets of electrode plates are configured in differential circuits.

14. The micro accelerometer of claim 10, wherein the proof masses are supported by a plurality of supporting anchors, where each of the supporting anchors is connected to each of the proof mass though a flexible supporter.

15. The micro accelerometer of claim 10, wherein the second proof mass and the third proof mass are arranged with a close loop control electrode respectively for controlling second proof mass and the third proof mass to move back to the original position when the second proof mass and the third proof mass generate displacement caused by an acceleration.

16. The micro accelerometer of claim 15, wherein the control electrode is rectangular electrode plate, which is arranged at the exterior side of the second proof mass and the third proof mass respectively.

17. The micro accelerometer of claim 15, wherein the control electrode comprises a electrode arranged between the two flexible supporters of the first proof mass.

18. The micro accelerometer of claim 15, wherein the control electrode comprises:

a first comb-like electrode, connected to the respective proof mass; and

a second comb-like electrode arranged to interleave with the first comb-like electrode.

19. A micro accelerometer comprising:

a first proof mass;

a second proof mass and a third proof mass arranged at each of the two opposite sides of the first proof mass, connected to the first proof mass by two flexible supporters and having a plurality of slots formed thereon, wherein the second proof mass and the third proof mass move along a first axial direction parallel to the first proof mass;

a fourth proof mass and a fifth proof mass arranged at each of the two opposite sides of the first proof mass, connected to the first proof mass by two flexible supporters and having a plurality of slots formed thereon, wherein the fourth proof mass and the fifth proof mass move along a second axial direction parallel to the first proof mass;

a plurality of electrode plate sets arranged relative to the second proof mass, the third proof mass, the fourth proof mass and the fifth proof mass respectively, for forming a plurality of sets of sensing electrodes of the first axial direction together with the second proof mass and the third proof mass and forming a plurality of sets of sensing electrodes of the second axial direction together with the fourth proof mass and the fifth proof mass, wherein the sensing electrodes are configured in differential circuits.

20. The micro accelerometer of claim 19, wherein the first proof mass comprises:

a frame;

an upper electrode plate; and

a plurality of flexible supporters connecting the frame and the upper electrode plate.

21. The micro accelerometer of claim 20, wherein the upper electrode plate further comprises a plurality of holes formed thereon.

22. The micro accelerometer of claim 19, wherein each set of electrode plates further comprises two sets of electrode plates interleaved with each other and parallel to the slots such that each of the slots covers portion of the electrode plates, where the two sets of electrode plates are configured in differential circuits.

23. The micro accelerometer of claim 19, wherein the proof masses are supported by a plurality of supporting anchors, where each of the supporting anchors is connected to each of the proof mass though a flexible supporter.

24. The micro accelerometer of claim 19, wherein the second proof mass and the third proof mass are arranged with a close loop control electrode respectively, for controlling the second proof mass and the third proof mass to move back to the original position when the second proof mass and the third proof mass generate displacement caused by an acceleration;

and the fourth proof mass and the fifth proof mass are arranged with a close loop control electrode respectively, for controlling the fourth proof mass and the fifth proof mass to move back to the original position when the fourth proof mass and the fifth proof mass generate displacement caused by an acceleration.

25. The micro accelerometer of claim 24, wherein the control electrode is rectangular electrode plate, which is arranged at the exterior side of the second proof mass, the third proof mass, the fourth proof mass and the fifth proof mass respectively.

26. The micro accelerometer of claim 24, wherein the control electrode comprises a electrode arranged between the two flexible supporters of the first proof mass.

27. The micro accelerometer of claim 24, wherein the control electrode comprises:

a first comb-like electrode, connected to the respective proof mass; and

a second comb-like electrode arranged to interleave with the first comb-like electrode.

28. A micro accelerometer comprising:

a first proof mass moving in the axial direction vertical to the first proof mass;

a second proof mass and a third proof mass arranged at each of the two opposite sides of the first proof mass, connected to the first proof mass by two flexible supporters and having a plurality of slots formed thereon, wherein the second proof mass and the third proof mass move along a first axial direction parallel to the first proof mass;

a fourth proof mass and a fifth proof mass arranged at each of the two opposite sides of the first proof mass, connected to the first proof mass by two flexible supporters and having a plurality of slots formed thereon, wherein the fourth proof mass and the fifth proof mass move along a second axial direction parallel to the first proof mass;

a lower electrode arranged relative to the first proof mass for forming a sensing capacitor together with the first proof mass; and

a plurality of electrode plate sets arranged relative to the second proof mass, the third proof mass, the fourth proof mass and the fifth proof mass respectively, for forming a plurality of sets of sensing electrodes of the first axial direction together with the second proof mass and the third proof mass and forming a plurality of sets of sensing electrodes of the second axial direction together with the fourth proof mass and the fifth proof mass, wherein the sensing electrodes are configured in differential circuits.

29. The micro accelerometer of claim 28, wherein the first proof mass comprises:

a frame;

an upper electrode plate; and

a plurality of flexible supporters connecting the frame and the upper electrode plate.

30. The micro accelerometer of claim 29, wherein the upper electrode plate further comprises a plurality of holes formed thereon.

31. The micro accelerometer of claim 28, wherein each set of electrode plates further comprises two sets of electrode plates interleaved with each other and parallel to the slots such that each of the slots covers portion of the electrode plates, where the two sets of electrode plates are configured in differential circuits.

32. The micro accelerometer of claim 28, wherein the proof masses are supported by a plurality of supporting anchors, where each of the supporting anchors is connected to each of the proof mass though a flexible supporter.

33. The micro accelerometer of claim 28, wherein the second proof mass and the third proof mass are arranged with a close loop control electrode respectively, for controlling the second proof mass and the third proof mass to move back to the original position when the second proof mass and the third proof mass generate displacement caused by an acceleration;

and the fourth proof mass and the fifth proof mass are arranged with a close loop control electrode respectively, for controlling the fourth proof mass and the fifth proof mass to move back to the original position when the fourth proof mass and the fifth proof mass generate displacement caused by an acceleration.

34. The micro accelerometer of claim 33, wherein the control electrode is rectangular electrode plate, which is arranged at the exterior side of the second proof mass, the third proof mass, the fourth proof mass and the fifth proof mass respectively.

35. The micro accelerometer of claim 33, wherein the control electrode comprises a electrode arranged between the two flexible supporters of the first proof mass.

36. The micro accelerometer of claim 33, wherein the control electrode comprises:

a first comb-like electrode, connected to the respective proof mass; and

a second comb-like electrode arranged to interleave with the first comb-like electrode.

37. A micro accelerometer comprising:

a base;

a proof mass arranged on the base and having a plurality of slots formed thereon, and moving in the axial direction parallel to the base; and

a plurality of electrode plate sets arranged relative to the proof mass for forming a plurality of sets of sensing electrodes of the axial direction, wherein the sensing electrodes are configured in differential circuits.

38. The micro accelerometer of claim 37, wherein each set of electrode plates further comprises two sets of electrode plates interleaved with each other and parallel to the slots such that each of the slots covers portion of the electrode plates, where the two sets of electrode plates are configured in differential circuits.

39. The micro accelerometer of claim 37, wherein the proof masses are supported by a plurality of supporting anchors, where each of the supporting anchors is connected to each of the proof mass though a flexible supporter.

40. The micro accelerometer of claim 37, wherein the proof mass is arranged with two close loop control electrodes positioned at the two sides of the proof mass, for controlling the proof mass to move back to the original position when the proof mass generates displacement caused by acceleration.

41. The micro accelerometer of claim 40, wherein the two close loop control electrodes relative to the proof mass are electrode plates.

42. The micro accelerometer of claim 40, wherein the two close loop control electrodes relative to the proof mass comprise:

a first comb-like electrode, connected to the respective proof mass; and

a second comb-like electrode arranged to interleave with the first comb-like electrode.

49. The micro accelerometer of claim 40, wherein the two close loop control electrodes relative to the proof mass comprise:

a first comb-like electrode, connected to the respective proof mass; and

a second comb-like electrode arranged to interleave with the first comb-like electrode.

43. A micro accelerometer comprising:

a base;

a first proof mass arranged on the base and having a plurality of slots formed thereon, and moving in the axial direction vertical to the base;

a second proof mass arranged on the base and having a plurality of slots formed thereon, and moving in a first axial direction parallel to the base;

a third proof mass arranged on the base and having a plurality of holes formed thereon, and moving in a second axial direction parallel to the base;

a lower electrode plate arranged relative to the first proof mass for forming a sensing capacitor together with the first proof mass; and

a plurality of electrode plate sets arranged relative to the second proof mass and the third proof mass, for forming a plurality of sets of sensing electrodes of the first axial direction together with the second proof mass, and forming a plurality of sets of sensing electrodes of the second axial direction together with the third proof mass, wherein the sensing electrodes are configured in differential circuits.

44. The micro accelerometer of claim 43, wherein the first proof mass comprises:

a upper electrode plate;

a plurality of flexible supporters connecting the upper electrode plate and the frame for restricting the proof mass composed of the upper electrode plate and the frame to move in the vertical direction; and

a plurality of supporting anchor, each of which connecting to each of the flexible supporters.

45. The micro accelerometer of claim 43, wherein each set of electrode plates further comprises two sets of electrode plates interleaved with each other and parallel to the slots such that each of the slots covers portion of the electrode plates, where the two sets of electrode plates are configured in differential circuits.

46. The micro accelerometer of claim 43, wherein the proof masses are supported by a plurality of supporting anchors, where each of the supporting anchors is connected to each of the proof mass though a flexible supporter.

47. The micro accelerometer of claim 43, wherein the second proof mass and the third proof mass are arranged with two close loop control electrodes positioned at the two sides of the relative proof mass, for controlling the second proof mass and the third proof mass to move back to the original position when the second proof mass and the third proof mass generate displacement caused by an acceleration.

48. The micro accelerometer of claim 47, wherein the two close loop control electrodes relative to the proof mass are electrode plates.