Apparatus and method for detecting a rotation

• US 7,895,892 B2
• Filed: 12/30/2008
• Issued: 03/01/2011
• Est. Priority Date: 06/30/2006
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Aigner, Robert
• Primary Examiner(s): Kwok; Helen C.
• Application Number:
  US12/346,287
• Publication Number:
  US 20090188317A1
• Time in Patent Office: 791 Days
• Field of Search: 735/040.1, 735/040.2, 735/040.4, 735/040.5, 735/041.2
• US Class Current: 73/504.01
• CPC Class Codes: G01C 19/5698 using acoustic waves, e.g. surface acoustic wave gyros

Abstract

A rotation sensor has a substrate with a first surface and a second surface. A shear-wave transparent mirror is arranged on the first surface of the substrate, and a shear-wave isolator is arranged above the shear-wave transparent mirror, the shear-wave transparent mirror and the shear-wave isolator being arranged separated from each other to define a Coriolis zone there between. A bulk-acoustic-wave resonator is arranged above the shear-wave isolator, and a shear-wave detector is arranged on the substrate in a direction, in which a shear-wave generated by the bulk-acoustic-wave resonator upon rotation propagates.

Claims

1. A rotation detection apparatus, comprising:

a first generator configured to generate a longitudinal bulk-acoustic-wave that propagates in a propagation direction;

a second generator configured to generate a shear-wave from the longitudinal bulk-acoustic wave upon rotation by an acting Coriolis force; and

a detector to detect the shear-wave,

wherein the second generator is arranged in the propagation direction between the first generator and the detector.

2. The rotation detection apparatus according to claim 1, wherein the first generator comprises a bulk-acoustic-wave resonator.

3. The rotation detection apparatus according to claim 1, further comprising a filter configured to filter the longitudinal bulk-acoustic-wave by suppressing longitudinal waves, the filter being arranged between the second generator and the detector.

4. The rotation detection apparatus according to claim 1, further comprising a suppressor configured to suppress the shear-wave, the suppressor arranged in a propagation direction of the shear-wave after the first generator.

5. The rotation detection apparatus according to claim 1, further comprising at least one reflector configured to reflect the shear-wave towards the detector.

6. The rotation detection apparatus according to claim 1, further comprising a determiner configured to determine rotation on the basis of a signal from the detector, the determiner generating a signal in case of an occurrence of the rotation.

7. The rotation detection apparatus according to claim 6, further comprising a further detector configured to detect a shear-wave, wherein the determiner determines the rotation based on a differential signal from the detector and from the further detector.

8. The rotation detection apparatus according to claim 6, further comprising a further detector configured to detect the shear-wave, wherein the determiner determines the rotation around a first axis of rotation based on a signal from the detector, and wherein the determiner determines the rotation around a second axis of rotation based on a signal from the further detector.

9. A rotation sensor, comprising:

a substrate;

a bulk-acoustic-wave generator disposed on the substrate;

a Coriolis zone arranged in a direction wherein a longitudinal bulk-acoustic-wave generated by the bulk-acoustic-wave generator propagates, and wherein an acting Coriolis force generates a shear-wave upon rotation from the longitudinal bulk-acoustic-wave; and

a shear-wave detector arranged on the substrate in a direction in which the shear-wave propagates.

10. The rotation sensor according to claim 9, wherein the bulk-acoustic-wave generator comprises a bulk-acoustic-wave resonator.

11. The rotation sensor according to claim 9, further comprising a shear-wave transparent mirror arranged between the substrate and the bulk-acoustic-wave generator.

12. The rotation sensor according to claim 11, further comprising a shear-wave isolator arranged between the bulk-acoustic-wave generator and the shear-wave transparent mirror, wherein the shear-wave isolator and the shear-wave transparent mirror are separated from each other to define the Coriolis zone.

13. The rotation sensor according to claim 9, further comprising a shear-wave reflector arranged on the substrate in a path along which the shear-wave propagates between the bulk-acoustic-wave generator and the shear-wave detector.

14. The rotation sensor according to claim 13, wherein the substrate comprises a line grating at one surface thereof, the line grating defining the shear-wave reflector.

15. The rotation sensor according to claim 9, further comprising an even number of shear-wave reflectors arranged on the substrate in a path along which the shear-wave propagates between the bulk-acoustic-wave generator and the shear-wave detector, the shear-wave reflectors being arranged on opposite surfaces of the substrate.

16. The rotation sensor according to claim 9, comprising an odd number of shear-wave reflectors arranged on the substrate in a path along which the shear-wave propagates between the bulk-acoustic-wave generator and the shear-wave detector, the shear-wave reflectors being arranged on a same surface of the substrate.

17. The rotation sensor according to claim 13, wherein the substrate comprises a dot grating at one surface thereof, the dot grating defining the shear-wave reflector.

18. The rotation sensor according to claim 9, further comprising a signal processing circuit, the signal processing circuit comprising an input for an output signal from the shear-wave detector and an output for a rotation signal.

19. The rotation sensor according to claim 18, further comprising a further shear-wave detector disposed on the substrate, wherein the signal processing circuit comprises a further input for an output signal from the further shear-wave detector, and wherein the output of the signal processing circuit is a rotation signal based on a difference between the output signal from the shear-wave detector and the output signal from the further shear-wave detector.

20. The rotation sensor according to claim 18, further comprising a further shear-wave detector disposed on the substrate, wherein the signal processing circuit comprises a further input for an output signal from the further shear-wave detector and a further output, wherein the output of the signal processing circuit is a rotation signal about a first axis based on the output signal from the shear-wave detector, and wherein the further output is a rotation signal about a second axis based on the output signal from the further shear-wave detector.

21. The rotation sensor according to claim 9, wherein the shear-wave detector comprises a tilted grain piezoelectric layer.

22. A rotation sensor, comprising:

a substrate comprising a first surface and a second surface;

a shear-wave transparent mirror arranged on the second surface of the substrate;

a shear-wave isolator over the shear-wave transparent mirror, wherein the shear-wave transparent mirror and the shear-wave isolator are arranged separated from each other to define a Coriolis zone there between;

a bulk-acoustic-wave resonator over the shear-wave isolator; and

a shear-wave detector arranged on the substrate in a direction in which a shear-wave generated upon rotation from a longitudinal bulk-acoustic-wave generated by the bulk-acoustic-wave resonator propagates.

23. The rotation sensor according to claim 22, wherein the shear-wave detector is arranged on the second surface of the substrate substantially opposite to the bulk-acoustic-wave resonator.

24. The rotation sensor according to claim 22, further comprising a shear-wave reflector arranged on the second surface of the substrate substantially opposite to the bulk-acoustic-wave resonator, wherein the shear-wave detector is arranged at the first surface of the substrate.

25. The rotation sensor according to claim 24, further comprising a layer arranged on the first surface of the substrate, wherein the bulk-acoustic-wave resonator is arranged on the layer, wherein the shear-wave transparent mirror and the shear-wave isolator are arranged within the layer below the bulk-acoustic-wave resonator, and wherein the shear-wave detector is arranged on the layer laterally spaced from the bulk-acoustic-wave resonator.

26. The rotation sensor according to claim 22, further comprising an even number of shear-wave reflectors arranged on the substrate in a path along which the shear-wave propagates between the bulk-acoustic-wave resonator and the shear-wave detector, the shear-wave reflectors being arranged on opposite surfaces of the substrate.

27. The rotation sensor according to claim 22, further comprising an odd number of shear-wave reflectors arranged on the substrate in a path along which the shear-wave propagates between the bulk-acoustic-wave resonator and the shear-wave detector, the shear-wave reflectors being arranged on a same surface of the substrate.

28. A method for detecting a rotation, comprising:

generating a longitudinal bulk-acoustic-wave propagating in a propagation direction; and

generating a shear-wave from the longitudinal bulk-acoustic-wave upon rotation by an acting Coriolis force, the shear-wave being generated in the propagation direction of the longitudinal bulk-acoustic wave; and

detecting the shear-wave generated from the longitudinal bulk-acoustic wave upon rotation.

29. The method according to claim 28, further comprising filtering the longitudinal bulk-acoustic wave to suppress longitudinal waves.

30. The method according to claim 28, further comprising determining the rotation on the basis of the detected shear-wave.

31. The method according to claim 28, further comprising reflecting the shear-wave and detecting a reflected shear-wave.