Microgyro tuning using focused ion beams

• US 20030101792A1
• Filed: 11/01/2002
• Published: 06/05/2003
• Est. Priority Date: 08/10/2001
• Status: Active Grant

• Current Assignee: The Boeing Co., Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Joyce, Richard, MʼCloskey, Robert Thomas, Kubena, Randall L., Challoner, A. Dorian
• Granted Patent: US 6,698,287 B2
• Time in Patent Office: Days
• US Class Current: 73/1.41
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis
• CPC Class Codes: G01P 2015/084 the mass being suspended at more than one of its sides, e.g. membrane-type suspension, so as to permit multi-axis movement of the mass

Abstract

The present invention discloses methods of manufacturing mechanical resonator microgyroscopes using focused ion beam machining and the mechanical resonator gyroscopes produced therefrom. An exemplary method of tuning a mechanical resonator gyroscope, includes the steps of mounting a mechanical resonator gyroscope in a vacuum chamber with a controllable focused ion beam where the gyroscope includes exciting and sensing elements for measuring a resonant frequency of the gyroscope. The exciting and sensing elements are activated to measure the resonant frequency of the mechanical resonator gyroscope and the resonant frequency of the gyroscope is adjusted to a desired resonant frequency value by controlling the focused ion beam to remove material of the gyroscope.

Claims

1. A method of tuning a mechanical resonator gyroscope, comprising the steps of:

mounting a mechanical resonator gyroscope in a vacuum chamber with a controllable focused ion beam where the gyroscope includes an exciting element and a sensing element for measuring a resonant frequency of the gyroscope;

activating the exciting and sensing elements to measure the resonant frequency of the mechanical resonator gyroscope; and

adjusting the resonant frequency of the gyroscope to a desired resonant frequency value by controlling the focused ion beam to remove material of the gyroscope.

2. The method of claim 1, wherein the mechanical resonator gyroscope comprises silicon.

3. The method of claim 1, wherein the mechanical resonator gyroscope is formed by micromachining.

4. The method of claim 1, wherein the exciting and sensing elements comprise capacitive electrodes.

5. The method of claim 1, wherein the resonant frequency of the gyroscope is measured and adjusted simultaneously.

6. The method of claim 1, wherein the material removal by the focused ion beam is performed at a sufficiently slow rate so that a change in the resonant frequency can be measured.

7. The method of claim 1, wherein the material is removed from an area of the gyroscope determined from finite element modeling analysis.

8. The method of claim 1, wherein the material is removed from a flexure beam thickness of the gyroscope.

9. A mechanical resonator gyroscope manufactured by the steps of:

mounting a mechanical resonator gyroscope in a vacuum chamber with a controllable focused ion beam where the gyroscope includes an exciting element and a sensing element for measuring at least one resonant frequency of the gyroscope;

activating the exciting and sensing elements to measure the resonant frequency of the mechanical resonator gyroscope; and

adjusting the resonant frequency of the gyroscope to a desired resonant frequency value by controlling the focused ion beam to remove material of the gyroscope.

10. The mechanical resonator gyroscope of claim 9, wherein the mechanical resonator gyroscope comprises silicon.

11. The mechanical resonator gyroscope of claim 9, wherein the mechanical resonator gyroscope is produced by micromachining.

12. The mechanical resonator gyroscope of claim 9, wherein the exciting and sensing elements comprise capacitive electrodes.

13. The mechanical resonator gyroscope of claim 9, wherein the resonant frequency of the gyroscope is measured and adjusted simultaneously.

14. The mechanical resonator gyroscope of claim 9, wherein the material removal by the focused ion beam is performed at a sufficiently slow rate so that a change in the resonant frequency can be measured.

15. The mechanical resonator gyroscope of claim 9, wherein the material is removed from an area of the gyroscope determined from finite element modeling analysis.

16. The mechanical resonator gyroscope of claim 9, wherein the material is removed from a flexure beam thickness of the gyroscope.