Micromachined devices

• US 20050274182A1
• Filed: 07/29/2005
• Published: 12/15/2005
• Est. Priority Date: 09/02/1997
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Geen, John A., Carow, Donald W.
• Granted Patent: US 7,406,866 B2
• Time in Patent Office: Days
• US Class Current: 73/504.120
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis

Abstract

A micromachined device has a body suspended over a substrate and movable in a plane relative to the substrate. The body has a perimeter portion, a first cross-piece portion extending from one part of the perimeter portion to another part of the perimeter portion to define at least first and second apertures, a first plurality of fingers extending along parallel axes from the perimeter portion into the first aperture, and a second plurality of fingers extending along parallel axes from the perimeter portion into the second aperture.

Claims

1. A micromachined gyro having a first structure that is dithered along a dither direction and is movable along a sensing direction orthogonal to the dither direction, with the movement along the sensing direction being sensed to provide a sensed signal indicative of a rotational velocity, wherein the device is packaged under ambient conditions.

2. The device of claim 1, wherein the dithering movement and the movement along the sensing direction are decoupled to minimize an interference signal.

3. A device comprising a micromachined gyroscope that has at least a first structure that is dithered along a dither direction and is movable along a sensing direction orthogonal to the dither direction, with the movement along the sensing direction being sensed to provide a sensed signal indicative of a rotational velocity, the dithering movement and the movement along the sensing direction being sufficiently decoupled so that an interference signal from the dithering movement is about 0.5 ppm of the sensed signal.

4. The device of claim 3, further comprising a package, wherein the gyroscope is packaged in the package in ambient conditions.

5. The device of claim 3, further comprising a second structure that is dithered along a dither direction and is movable along a sensing direction orthogonal to the dither direction, with the movement along the sensing direction being sensed to provide a sensed signal indicative of a rotational velocity, the dithering movement and the movement along the sensing direction being sufficiently decoupled so that an interference signal from the dithering movement is no more than about 0.5 ppm of the sensed signal, wherein the first and second structures are electrically coupled to reduce the interference signal from what it would be for either of the first or second structures separately.

6. The device of claim 5, wherein each of the first and second structures includes one or more electrodes that move with the respective structure when the structure moves in the sensing direction, the device further including fixed electrodes for each of the first and second structures, the structures thereby detecting movement by sensing a change in capacitance between the movable electrodes and the fixed electrodes, wherein at least some of the fixed electrodes for the first structure are coupled to at least some of the fixed electrodes for the second structure.

7. The device of claim 5, wherein the first and second structures are dithered by substantially identical first and second means for driving, wherein the first driving means of the first structure is coupled to the second driving means of the second structure, and the second driving means of the first structure is coupled to the first driving means of the second structure.

8. The device of claim 5, further comprising a third structure and a fourth structure, each of the first, second, third, and fourth structures having drive means for dithering and capacitive sensing means, all of which are substantially identical to each other, the drive means and capacitive sensing means electrically coupled together to reduce the interference signal relative to each structure.

9. The device of claim 3, wherein the structure includes two structures interconnected to decouple movement along the dither direction and the sensing direction.