Micromachined rate and acceleration sensor

• US 5,962,784 A
• Filed: 10/14/1997
• Issued: 10/05/1999
• Est. Priority Date: 05/27/1997
• Status: Expired due to Term

• Current Assignee: L-3 Communications Corporation (L3Harris Technologies, Inc.)
• Original Assignee: Alliedsignal Inc. (Honeywell International Inc.)
• Inventors: Hulsing, Rand H. II
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): MOLLER, RICHARD ALAN
• Application Number:
  US08/949,883
• Time in Patent Office: 721 Days
• Field of Search: 73/504.02, 73/504.03, 73/504.04, 73/510, 73/511, 73/504.12, 73/504.14, 73/504.16, 73/514.36, 73/514.38, 73/514.29
• US Class Current: 73/504.03
• CPC Class Codes: G01C 19/5755 the devices having a single sensing mass
• CPC Class Codes: G01C 19/5769 Manufacturing; Mounting; Housings
• CPC Class Codes: G01P 15/097 by vibratory elements

Abstract

A monolithic substrate for acceleration and angular rate sensing. The substrate comprises a support frame, and a first accelerometer formed in the substrate. The first accelerometer has a proof mass including first and second opposite edges. A flexure connects the first edge of the proof mass to the support frame. The flexure defines a hinge axis for the proof mass. The first accelerometer further includes a torsion stabilizing strut coupling a portion of the proof mass to the frame.

Claims

1. A monolithic substrate for acceleration and angular rate sensing, the substrate comprising:

a support frame;

a first accelerometer formed in the substrate, the first accelerometer having a proof mass including first and second opposite edges, and third and fourth opposite edges, a flexure connecting the first edge of the proof mass to the support frame, the flexure defining a hinge axis for the proof mass, a first force-sensing member coupled between the proof mass and the support frame at a location intermediate the hinge axis and the second edge with respect to a direction extending from the first edge to the second edge and intermediate the third and fourth edges with respect to a direction extending from the third edge to the fourth edge; and

a second accelerometer formed in the substrate, the second accelerometer having a second proof mass including fifth and sixth opposite edges, and seventh and eighth opposite edges, a flexure connecting the fifth edge to the support frame, the flexure of the second accelerometer defining a hinge axis for the second proof mass, a second force-sensing member coupled between the second proof mass and the support frame at a location intermediate the hinge axis of the second accelerometer and the sixth edge with respect to a direction extending from the fifth edge to the sixth edge and intermediate the seventh and eighth edges with respect to a direction extending from the seventh edge to the eighth edge.

2. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 1, wherein the first force-sensing member comprises a vibratable beam.

3. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 1, wherein the first force-sensing member comprises a pair of vibratable beams.

4. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 1, wherein the second force-sensing member comprises a vibratable beam.

5. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 1, wherein the second force-sensing member comprises a pair of vibratable beams.

6. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 2 wherein the entirety of the vibratable beam is disposed between the hinge axis of the first accelerometer and the second edge.

7. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 4 wherein the entirety of the vibratable beam is disposed between the hinge axis of the second accelerometer and the sixth edge.

8. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 3 wherein the full lengths of the vibratable beams are disposed between the hinge axis of the second accelerometer and the sixth edge.

9. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 5 wherein the full lengths of the vibratable beams are disposed between the hinge axis of the second accelerometer and the sixth edge.

10. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 1 wherein the hinge axis of the first accelerometer and the hinge axis of the second accelerometer define a common axis.

11. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 2 wherein the vibratable beam is elongated along a direction that is substantially normal to the hinge axis of the first accelerometer.

12. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 3 wherein the vibratable beams are elongated along respective directions that are both substantially normal to the hinge axis of the second accelerometer.

13. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 1 wherein the first force-sensing member comprises a vibratable beam and the second force-sensing member comprises a different vibratable beam.

14. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 1 wherein the flexure of the first accelerometer includes first and second spaced apart flexure portions, and wherein a portion of the frame extends intermediate the first and second portions toward the second edge.

15. A monolithic substrate for acceleration and angular rate sensing, the substrate comprising:

a support frame; and

an accelerometer formed in the substrate, the accelerometer having a proof mass including first and second legs and a main body portion connecting the legs and accommodating common movement of the legs, a flexure including first and second spaced apart flexure portions respectively connecting the first and second legs to the support frame, the flexure defining a hinge axis for the proof mass.

16. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 15 wherein said support frame comprises a post disposed between the flexure portions and extending toward the main body portion and between the legs and further comprising a first vibratable beam coupled to the proof mass at a location intermediate the hinge axis and the main body portion with respect to a direction extending from the hinge axis to the main body portion, and a second vibratable beam proximate the first beam and coupled to the post at a location intermediate the hinge axis and the main body portion with respect to a direction extending from the hinge axis to the main body portion.

17. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 16 wherein the first and second beams are elongated along respective directions that are both substantially normal to the hinge axis.

18. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 16 and further comprising a conductive path coupled to the first beam and extending at least partially along the post.

19. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 18 and further comprising a conductive path coupled to the second beam and extending at least partially along the post.

20. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 15 and further comprising a second accelerometer formed in the substrate and having a second proof mass including third and fourth legs and a main body portion connecting the third and fourth legs and accommodating common movement of the third and fourth legs, a second flexure including third and fourth spaced apart flexure portions respectively connecting the third and fourth legs to the support frame, the second flexure defining a hinge axis for the second proof mass, wherein the support frame further includes a second post, and wherein the second post is disposed between the third and fourth flexure portions and extends toward the main body portion of the second accelerometer between the third and fourth legs.

21. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 20 wherein the hinge axes of both accelerometers are coaxial.

22. A monolithic substrate for acceleration and angular rate sensing, the substrate comprising:

a support frame; and

a first accelerometer formed in the substrate, the first accelerometer having a proof mass including first and second opposite edges, a flexure connecting the first edge of the proof mass to the support frame, the flexure defining a hinge axis for the proof mass, and a torsion stabilizing strut coupling a portion of the proof mass to the support frame, the strut being positioned closer to the flexure than the second edge.

23. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 22 wherein the proof mass further has first and second surfaces defining respective first and second planes, wherein the hinge axis is generally parallel to said planes, wherein the flexure is closer to the second surface than to the first surface with respect to a direction normal to the first plane, and wherein at least a portion of the strut overlies the flexure.

24. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 22 and further comprising a second accelerometer formed in the substrate the accelerometer having a second proof mass including first and second opposite edges, a second flexure connecting the first edge of the second proof mass to the support frame, the second flexure defining a hinge axis for the second proof mass, and a second torsion stabilizing strut coupling a portion of the second proof mass to the frame, the second strut being positioned closer to the second flexure than to the second edge of the second proof mass.

25. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 24 wherein the hinge axis for the second proof mass is closer to the hinge axis for the first proof mass than to the second edge of the first proof mass.

26. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 22 wherein the proof mass further includes third and fourth opposite edges, and wherein the substrate further comprises a first vibratable beam coupled to the proof mass at a location intermediate the hinge axis and the second edge with respect to a direction extending from the first edge to the second edge and intermediate the third and fourth edges with respect to a direction extending from the third edge to the fourth edge, and a second vibratable beam proximate the first beam and coupled to the frame at a location intermediate the hinge axis and the second edge with respect to a direction extending from the first edge to the second edge and intermediate the third and fourth edges with respect to a direction extending from the third edge to the fourth edge.

27. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 22 further comprising:

a hair spring flexure connected with and between the support frame and a portion of the substrate; and

a conductive path supported by the substrate at least a portion of which extends over the hair spring flexure.

28. A monolithic substrate for acceleration and angular rate sensing in accordance with claim 27, wherein the conductive path comprises a contact pad and the hair spring flexure is configured with a reverse bend intermediate the contact pad and the support frame.