Micromachined apparatus with drive/sensing fingers in coupling levers

• US 20060191339A1
• Filed: 02/23/2006
• Published: 08/31/2006
• Est. Priority Date: 02/06/2002
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Geen, John A.
• Granted Patent: US 7,204,144 B2
• Time in Patent Office: Days
• US Class Current: 73/504.15
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis
• CPC Class Codes: Y10T 74/12 Gyroscopes

Abstract

Resonator structures include a plurality of resonator masses interconnected by a plurality of levers so as to resonate in anti-phase with one another. The levers include a plurality of lever fingers interdigitated with corresponding fixed fingers affixed to an underlying substrate for at least one of driving movement of the levers and sensing movement of the levers relative to the fixed fingers.

Claims

1. Apparatus comprising:

a substrate;

a plurality of fixed fingers affixed to the substrate; and

a plurality of resonator structures, the resonator structures including a plurality of masses interconnected by a plurality of levers so as to resonate in anti-phase with one another, the levers including a plurality of lever fingers interdigitated with the fixed fingers for at least one of driving movement of the levers and sensing movement of the levers relative to the fixed fingers.

2. Apparatus according to claim 1, wherein the fixed fingers and the lever fingers are capacitively coupled for driving movement of the levers.

3. Apparatus according to claim 1, wherein the fixed fingers and the lever fingers are capacitively coupled for sensing movement of the levers.

4. Apparatus according to claim 1, wherein each of the levers moves with an arcuate motion, and wherein the lever fingers are disposed at varying angles so as to maintain substantially equal distances from said corresponding fixed fingers during movement of the levers.

5. Apparatus according to claim 1, wherein the plurality of levers transform the coupled motion of the resonating structures from co-linear motion to parallel motion.

6. Apparatus according to claim 1, wherein the plurality of resonator structures are disposed within an inner perimeter of a frame and operate substantially within the plane of the frame, the resonating structures mechanically coupled to produce substantially a single resonance frequency and to restrict transfer of inertial forces from the resonating structures to the frame.

7. Apparatus according to claim 6, wherein each of the plurality of levers is coupled at one end to the frame and at another end to a different one of the masses, and wherein each lever has pivots, defined at the points of attachment to the frame and the mass by the intersection of the axes of at least two orthogonal flexures, to ensure that the attachment point cannot translate with respect to the lever.

8. Apparatus according to claim 6, wherein the frame is suspended from the substrate by a plurality of accelerometer suspension flexures, the accelerometer suspension flexures designed so as to restrict translational movement of the frame in the plane of the substrate and to allow rotational movement of the frame in the plane of the substrate, wherein rotational movement of the apparatus in the plane of the substrate causes rotation of the frame relative to the substrate in the plane of the substrate.

9. Apparatus according to claim 8, further comprising:

a plurality of frame fingers disposed along the outer perimeter of the frame, the frame fingers interdigitated with corresponding sensing fingers affixed to the substrate for sensing rotational movement of the frame.

10. Apparatus according to claim 9, wherein the outer perimeter of the frame is substantially square and includes a plurality of frame fingers disposed along each side of the frame.

11. Apparatus according to claim 10, wherein the frame fingers are disposed at varying angles so as to maintain substantially equal distances from said corresponding sensing fingers during rotational movement of the frame.

12. Apparatus according to claim 8, wherein the accelerometer suspension flexures are arranged at the corners of the frame.

13. Apparatus according to claim 1, wherein each mass includes a plurality of drive fingers interdigitated with corresponding drive electrodes affixed to the substrate.

14. Apparatus according to claim 1, wherein each mass includes a notch for quadrature suppression.

15. Apparatus according to claim 1, wherein the plurality of resonating structures and the fixed drive fingers are micromachined from a single wafer.