Tuning fork vibratory MEMS gyroscope

• US 20060117852A1
• Filed: 03/03/2005
• Published: 06/08/2006
• Est. Priority Date: 12/03/2004
• Status: Active Grant

• Current Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group)
• Original Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group)
• Inventors: Kim, Yong Sik, Park, Kyoo Yeon
• Granted Patent: US 7,191,653 B2
• Time in Patent Office: Days
• US Class Current: 73/504.160
• CPC Class Codes: G01C 19/5747 each sensing mass being connected to a driving mass, e.g. driving frames
• CPC Class Codes: G01P 15/0888 for indicating angular acceleration

Abstract

A tuning fork vibratory MEMS gyroscope for sensing angular velocity and angular acceleration generated due to the rotation of a movable body. The tuning fork vibratory MEMS gyroscope includes an external fixed support portion formed on a substrate; a plurality of external elastic members; first and second external frames respectively including driving combs; first and second driving electrodes respectively including comb drivers; first and second internal elastic members respectively including a plurality of spring members; first and second internal frames respectively including sensing combs; and first and second sensing electrodes respectively including comb sensors. The tuning fork vibratory MEMS gyroscope withstands a noise at a peripheral area, is driven at the external portions of internal frames, is sensed at the internal portions of the internal frames, and comprises the elastic members having a wine glass shape, thereby being more stably operated.

Claims

1. A tuning fork vibratory MEMS gyroscope comprising:

an external fixed support portion formed on a substrate having a flat structure in a horizontal direction by the X-axis and the Y-axis, which meet at a right angle;

a plurality of external elastic members connected to the inner sides of the external fixed support portion, and having elasticity in the direction of the Y-axis;

first and second external frames separated from the substrate by a designated interval, elastically supported by the plural external elastic members, disposed on the Y-axis such that the first and second external frames are separated from each other, and respectively including driving combs, having a designated length in the direction of the Y-axis, at a part of the inner sides thereof;

first and second driving electrodes fixed to the substrate, respectively disposed inside the first and second external frames such that the first and second driving electrodes are separated from the inner sides of the first and second external frames, and respectively including comb drivers separated from the corresponding driving combs and engaged with the corresponding driving combs;

first and second internal elastic members respectively connected to the inner sides of the first and second external frames, and having elasticity in the direction of the X-axis;

first and second internal frames separated from the substrate by a designated interval, respectively disposed inside the first and second external frames such that the first and second internal frames are separated from the inner sides of the first and second external frames, elastically supported by the first and second internal elastic members, and respectively including sensing combs, having a designated length in the direction of the Y-axis, at a part of the inner sides thereof; and

first and second sensing electrodes fixed to the substrate, respectively disposed inside the first and second internal frames such that the first and second sensing electrodes are separated from the inner sides of the first and second internal frames, and respectively including comb sensors separated from the corresponding sensing combs by a designated interval and engaged with the corresponding sensing combs.

2. The tuning fork vibratory MEMS gyroscope as set forth in claim 1, wherein the external fixed support portion includes:

first and second Y-axis frame bars separated from each other and aligned in parallel in the direction of the Y-axis; and

first and second X-axis frame bars connected to both ends of the first and second Y-axis frame bars, separated from each other, and aligned in parallel in the direction of the X-axis.

3. The tuning fork vibratory MEMS gyroscope as set forth in claim 2, wherein the external elastic members include:

first and second external elastic members respectively made of elastic bars having a designated length in the direction of the X-axis, ends of which are connected to the inner side of the external fixed support portion and the other ends of which are connected to the first external frame;

third and fourth external elastic members respectively made of elastic bars having a designated length in the direction of the X-axis, ends of which are connected to the inner side of the external fixed support portion and the other ends of which are connected to the second external frame; and

a fifth external elastic member made of an elastic body having a right-laid wine glass shape, both ends of a left side of which are connected to a central part of the inner surface of the first Y-axis frame bar of the external fixed support portion and both ends of a right side of which are respectively connected to the first and second external frames of the external fixed support portion; and

a sixth external elastic member made of an elastic body having a left-laid wine glass shape, both ends of a right side of which are connected to a central part of the inner surface of the second Y-axis frame bar of the external fixed support portion and both ends of a left side of which are respectively connected to the first and second external frames of the external fixed support portion.

4. The tuning fork vibratory MEMS gyroscope as set forth in claim 3,

wherein the first and second external elastic members have symmetrical structures with each other with respect to the Y-axis.

5. The tuning fork vibratory MEMS gyroscope as set forth in claim 4,

wherein the third and fourth external elastic members have symmetrical structures with each other with respect to the Y-axis.

6. The tuning fork vibratory MEMS gyroscope as set forth in claim 5,

wherein the fifth and sixth external elastic members have symmetrical structures with each other with respect to the Y-axis.

7. The tuning fork vibratory MEMS gyroscope as set forth in claim 6,

wherein the firth and third external elastic members have symmetrical structures with each other with respect to the X-axis.

8. The tuning fork vibratory MEMS gyroscope as set forth in claim 7,

wherein the second and fourth external elastic members have symmetrical structures with each other with respect to the X-axis.

9. The tuning fork vibratory MEMS gyroscope as set forth in claim 8,

wherein each of the fifth and sixth external elastic members has a symmetrical structure with respect to the X-axis.

10. The tuning fork vibratory MEMS gyroscope as set forth in claim 9, wherein the elastic body of the fifth external elastic member includes:

a first connection portion having a cup shape, which is opened toward the first Y-axis frame bar of the external fixed support portion, and connected to the central part of the inner surface of the first Y-axis frame bar;

a second connection portion having a cup shape, which is opened toward the second Y-axis frame bar of the external fixed support portion, and provided with both ends respectively connected to the first and second external frames; and

a third connection portion for connecting the central part of the first connection portion and the central part of the second connection portion.

11. The tuning fork vibratory MEMS gyroscope as set forth in claim 9, wherein the elastic body of the sixth external elastic member includes:

a first connection portion having a cup shape, which is opened toward the second Y-axis frame bar of the external fixed support portion, and connected to the central part of the inner surface of the second Y-axis frame bar;

a second connection portion having a cup shape, which is opened toward the first Y-axis frame bar of the external fixed support portion, and provided with both ends respectively connected to the first and second external frames; and

a third connection portion for connecting the central part of the first connection portion and the central part of the second connection portion.

12. The tuning fork vibratory MEMS gyroscope as set forth in claim 1, wherein each of the first and second external frames respectively includes:

first and second Y-axis frame bars separated from each other and aligned in parallel in the direction of the Y-axis; and

first and second X-axis frame bars connected to ends of the first and second Y-axis frame bars, separated from each other, and aligned in parallel in the direction of the X-axis.

13. The tuning fork vibratory MEMS gyroscope as set forth in claim 12,

wherein the driving comb of the first external frame is formed on the first X-axis frame bar of the first external frame, and the driving comb of the second external frame is formed on the second X-axis frame bar of the second external frame.

14. The tuning fork vibratory MEMS gyroscope as set forth in claim 13, wherein each of the first and second driving electrodes further includes:

a driving electrode pad fixedly supported by the substrate; and

a driving electrode beam extended from both sides of the driving electrode pad by a designated length in the direction of the X-axis,

wherein the comb drivers of the first and second driving electrodes are respectively formed on the driving electrode pads and the driving electrode beams.

15. The tuning fork vibratory MEMS gyroscope as set forth in claim 12, wherein the driving comb of the first external frame is formed on the second X-axis frame bar of the first external frame, and the driving comb of the second external frame is formed on the first X-axis frame bar of the second external frame.

16. The tuning fork vibratory MEMS gyroscope as set forth in claim 15, wherein each of the first and second driving electrodes further includes:

a driving electrode pad fixedly supported by the substrate; and

a driving electrode beam extended from both sides of the driving electrode pad by a designated length in the direction of the X-axis,

wherein the comb drivers of the first and second driving electrodes are respectively formed on the driving electrode pads and the driving electrode beams.

17. The tuning fork vibratory MEMS gyroscope as set forth in claim 12, wherein the first internal elastic member includes:

first and second internal spring members respectively made of Y-axis bars having a designated length in the direction of the Y-axis, ends of which are connected to the first X-axis frame bar of the first external frame and the other ends of which are connected to the first internal frame; and

third and fourth internal spring members respectively made of Y-axis bars having a designated length in the direction of the Y-axis, ends of which are connected to the second X-axis frame bar of the first external frame and the other ends of which are connected to the first internal frame.

18. The tuning fork vibratory MEMS gyroscope as set forth in claim 17, wherein the first and second internal 15 spring members have symmetrical structures with each other with respect to the Y-axis, and the third and fourth internal spring members have symmetrical structures with each other with respect to the Y-axis.

19. The tuning fork vibratory MEMS gyroscope as set forth in claim 17, wherein the first and third internal spring members have symmetrical structures with each other with respect to the X-axis, and the second and fourth internal spring members have symmetrical structures with each other with respect to the X-axis.

20. The tuning fork vibratory MEMS gyroscope as set forth in claim 12, wherein the second internal elastic member includes:

first and second internal spring members respectively made of Y-axis bars having a designated length in the direction of the Y-axis, ends of which are connected to the first X-axis frame bar of the second external frame and the other ends of which are connected to the second internal frame; and

third and fourth internal spring members respectively made of Y-axis bars having a designated length in the direction of the Y-axis, ends of which are connected to the second X-axis frame bar of the second external frame and the other ends of which are connected to the second internal frame.

21. The tuning fork vibratory MEMS gyroscope as set forth in claim 20, wherein the first and second internal spring members have symmetrical structures with each other with respect to the Y-axis, and the third and fourth internal spring members have symmetrical structures with each other with respect to the Y-axis.

22. The tuning fork vibratory MEMS gyroscope as set forth in claim 20, wherein the first and third internal spring members have symmetrical structures with each other with respect to the X-axis, and the second and fourth internal spring members have symmetrical structures with each other with respect to the X-axis.

23. The tuning fork vibratory MEMS gyroscope as set forth in claim 1, wherein each of the first and second internal frames includes:

first and second Y-axis frame bars separated from each other and aligned in parallel in the direction of the Y-axis; and

first and second X-axis frame bars connected to ends of the first and second Y-axis frame bars, separated from each other, and aligned in parallel in the direction of the X-axis.

24. The tuning fork vibratory MEMS gyroscope as set forth in claim 23, wherein the sensing comb of the first internal frame is formed on the first X-axis frame bar of the first internal frame, and the sensing comb of the second internal frame is formed on the second X-axis frame bar of the second internal frame.

25. The tuning fork vibratory MEMS gyroscope as set forth in claim 24, wherein the first sensing electrode includes:

a sensing electrode pad fixedly supported by the substrate; and

a sensing electrode bar extended from both sides of the sensing electrode pad by a designated length in the direction of the X-axis,

wherein the comb sensor of the first sensing electrode is formed on the sensing electrode pad and the sensing electrode bar.

26. The tuning fork vibratory MEMS gyroscope as set forth in claim 25, wherein the second sensing electrode includes:

a sensing electrode pad fixedly supported by the substrate; and

a sensing electrode bar extended from both sides of the sensing electrode pad by a designated length in the direction of the X-axis,

wherein the comb sensor of the second sensing electrode is formed on the sensing electrode pad and the sensing electrode bar.

27. The tuning fork vibratory MEMS gyroscope as set forth in claim 23, wherein the sensing comb of the first internal frame is formed on the second X-axis frame bar of the first internal frame, and the sensing comb of the second internal frame is formed on the first X-axis frame bar of the second internal frame.

28. The tuning fork vibratory MEMS gyroscope as set forth in claim 27, wherein the first sensing electrode includes:

a sensing electrode pad fixedly supported by the substrate; and

a sensing electrode bar extended from both sides of the sensing electrode pad by a designated length in the direction of the X-axis,

wherein the comb sensor of the first sensing electrode is formed on the sensing electrode pad and the sensing electrode bar.

29. The tuning fork vibratory MEMS gyroscope as set forth in claim 28, wherein the second sensing electrode includes:

a sensing electrode pad fixedly supported by the substrate; and

a sensing electrode bar extended from both sides of the sensing electrode pad by a designated length in the direction of the X-axis,

wherein the comb sensor of the second sensing electrode is formed on the sensing electrode pad and the sensing electrode bar.

30. The tuning fork vibratory MEMS gyroscope as set forth in claim 23, wherein the sensing comb of the first internal frame is formed on the first and second X-axis frame bars of the first internal frame, and the sensing comb of the second internal frame is formed on the first and second X-axis frame bars of the second internal frame.

31. The tuning fork vibratory MEMS gyroscope as set forth in claim 30, wherein the first sensing electrode includes:

a sensing electrode pad fixedly supported by the substrate; and

a sensing electrode bar extended from both sides of the sensing electrode pad by a designated length in the direction of the X-axis,

wherein the comb sensor of the first sensing electrode is formed on the sensing electrode pad and the sensing electrode bar.

32. The tuning fork vibratory MEMS gyroscope as set forth in claim 31, wherein the second sensing electrode includes:

a sensing electrode pad fixedly supported by the substrate; and

a sensing electrode bar extended from both sides of the sensing electrode pad by a designated length in the direction of the X-axis,

wherein the comb sensor of the second sensing electrode is formed on the sensing electrode pad and the sensing electrode bar.

33. The tuning fork vibratory MEMS gyroscope as set forth in claim 1, wherein each of the first and second external frames further includes a plurality of feedback sensing combs aligned on the neighboring two X-axis frame bars, out of the X-axis frame bars of the first and second external frames, in the direction of the Y-axis.

34. The tuning fork vibratory MEMS gyroscope as set forth in claim 33, further comprising a feedback electrode formed between the first and second external frames for sensing capacitances corresponding to intervals with the feedback sensing combs of the first and second external frames.

35. The tuning fork vibratory MEMS gyroscope as set forth in claim 34, wherein the feedback electrode includes:

a feedback electrode pad fixed to the substrate;

a feedback electrode beam extended from both sides of the feedback electrode pad in the direction of the X-axis; and

a feedback comb sensor having fingers continuously aligned on the feedback electrode pad and the feedback electrode beam in the direction of the Y-axis, separated from the feedback sensing combs of the first and second external frames, and engaged with the feedback sensing combs.