Silicon gyro with integrated driving and sensing structures

• US 6,374,672 B1
• Filed: 07/28/2000
• Issued: 04/23/2002
• Est. Priority Date: 07/28/2000
• Status: Expired due to Term

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Litton Systems Incorporated
• Inventors: Abbink, Henry C., Choi, Youngmin A.
• Primary Examiner(s): Moller, Richard A.
• Application Number:
  US09/627,549
• Time in Patent Office: 634 Days
• Field of Search: 735/041.2, 735/040.8
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis

Abstract

A rotation sensor is formed of three semiconductor wafers. A first wafer comprises a frame that surrounds a paddle. The rotation-sensitive paddle is surrounded on either of the opposed sides of the first wafer by rings of driven elements formed of radially-directed plateaus in the semiconductor material. Second and third wafers sandwich the first wafer. Each of the second and third wafers includes a first surface in which are formed concentric rings of driver and pickoff electrodes. In a preferred embodiment, the rings of pickoff electrodes are split into two semicircular arcs.

Claims

1. A rotation sensor comprising, in combination:

a) a first generally-planar wafer including a paddle;

b) said first wafer further including a plurality of driven elements defined at its opposed sides;

c) a second generally-planar wafer, said wafer having a plurality of driver electrodes defined on a first surface thereof;

d) a third generally-planar wafer, said wafer having a plurality driver electrodes defined on a first surface thereof;

e) said first wafer being arranged relative to said second and third wafers so that said first surfaces of said second and third wafers face said opposed surfaces of said first wafer;

f) a first pair of electrodes defined on said first surface of said second wafer and substantially aligned with said paddle; and

g) a second pair of electrodes defined on said first surface of said third wafer and substantially aligned with said paddle.

2. A rotation sensor as defined in claim 1 further characterized in that:

a) said driven elements comprise radially-directed plateaus defined within said opposed surfaces of said first wafer; and

b) said driver electrodes comprise radially-directed plateaus formed within said first surfaces of said second and third wafers.

3. A rotation sensor as defined in claim 2 further characterized in that:

a) said driven elements are arranged into rings formed on said opposed surfaces of said first wafer;

b) said driver electrodes are arranged into rings on said first surfaces of said second and third wafers; and

c) said rings substantially overlap one another.

4. A rotation sensor as defined in claim 3 further characterized in that:

a) said paddle is substantially round; and

b) said paddle is located interior to said rings of driven elements.

5. A rotation sensor as defined in claim 4 wherein said first wafer further comprises:

a) a peripheral frame;

b) a plurality of radially-directed beams extending inwardly from said frame to and supporting said rings of driven elements; and

c) at least one pair of aligned torsion bars extending inwardly from said rings of driven elements to and supporting said paddled.

6. A rotation sensor as defined in claim 5 further including:

a) a plurality of pickoff electrodes formed in said first surfaces of said second and third wafers;

b) said pickoff electrodes comprising radially-directed plateaus formed in said first surfaces of said second and third wafers;

c) said plateaus of pickoff electrodes being formed into rings on said first surfaces of said second and third wafers; and

d) each of said rings of pickoff electrodes being concentric with a ring of driver electrodes.

7. A rotation sensor as defined in claim 6 wherein said pickoff electrode rings are electrically insulated from said driver electrode rings.

8. A rotation sensor as defined in claim 7 wherein:

a) each of said rings of pickoff electrodes comprises a pair of semicircular rings; and

b) said semicircular rings are electrically insulated from one another.

9. A rotation sensor as defined in claim 3 further characterized in that:

a) the number of driver electrodes is equal to the number of facing driven elements; and

b) each of said driven elements is offset by an equal amount from each of said driver electrodes at null.

10. A rotation sensor as defined in claim 9 wherein each of said driven elements is offset by 180 degrees from the facing driver electrode at null.

11. A rotation sensor as defined in claim 1 further characterized in that:

a) said first pair of electrodes comprises two metallized arcuate sections; and

b) said second pair of electrodes comprises two metallized arcuate sections.

12. A rotation sensor as defined in claim 3 wherein:

a) said first pair of electrodes lies within said rings of driver electrodes formed on said first surface of said second wafer; and

b) said second pair of electrodes lies within said rings of driver electrodes formed on said first surface of said third wafer.

13. A rotation sensor as defined in claim 6 wherein:

a) said rings of pickoff electrodes in said first surface of said second wafer lies within said rings of driver electrodes in said first surface of said second wafer; and

b) said rings of pickoff electrodes in said first surface of said third wafer lies within said rings of driver electrodes within said first surface of said third wafer.

14. A rotation sensor comprising, in combination:

a) a first generally-planar silicon wafer comprising a frame surrounding a substantially-round paddle;

b) said first wafer further including a plurality of driven elements defined at its opposed sides;

c) a second generally-planar silicon wafer, said wafer having a plurality of driver electrodes defined on a first surface thereof;

d) a third generally-planar silicon wafer, said wafer having a plurality driver electrodes defined on a first surface thereof;

e) said first wafer being arranged with respect to said second and third wafers so that said first surfaces of said second and third wafers face said opposed surfaces of said first wafer;

f) a first pair of electrodes defined on said first surface of said second wafer and substantially aligned with said paddle; and

g) a second pair of electrodes defined on said first surface of said third wafer and substantially aligned with said paddle.

15. A rotation sensor as defined in claim 14 further characterized in that:

a) said driven elements comprise radially-directed plateaus defined within said opposed surfaces of said first wafer; and

b) said driver electrodes comprise radially-directed plateaus formed within said first surfaces of said second and third wafers.

16. A rotation sensor as defined in claim 15 further characterized in that:

a) said driven elements are arranged into rings formed on said opposed surfaces of said first wafer;

b) said driver electrodes are arranged into rings on said first surfaces of said second and third wafers; and

c) said rings substantially overlap one another.

17. A rotation sensor as defined in claim 16 further including:

a) a plurality of pickoff electrodes formed in said first surfaces of said second and third wafers;

b) said pickoff electrodes comprising radially-directed plateaus formed in said first surfaces of said second and third wafers;

c) said plateaus of pickoff electrodes being formed into rings on said first surfaces of said second and third wafers; and

d) each of said rings of pickoff electrodes being concentric with a ring of driver electrodes.

18. A rotation sensor as defined in claim 17 wherein said pickoff electrode rings are electrically insulated from said driver electrode rings.

19. A rotation sensor as defined in claim 18 wherein:

a) each of said rings of pickoff electrodes comprises a pair of semicircular rings; and

b) said semicircular rings are electrically insulated from one another.

20. A rotation sensor as defined in claim 16 further characterized in that:

a) the number of driver electrodes is equal to the number of facing driven elements; and

b) each of said driven elements is offset by an equal amount from each of said driver electrodes at null.

21. A rotation sensor as defined in claim 20 wherein each of said driven elements is offset by 180 degrees from the facing driver electrode at null.