Micromachined piezoelectric z-axis gyroscope
This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for making and using gyroscopes. Such gyroscopes may include a central anchor, a sense frame disposed around the central anchor, a plurality of sense beams configured for connecting the sense frame to the central anchor and a drive frame disposed around and coupled to the sense frame. The gyroscope may include pairs of drive beams disposed on opposing sides of the sense frame. The gyroscope may include a drive frame suspension for substantially restricting a drive motion of the drive frame to that of a substantially linear displacement along the first axis. The sense frame may be substantially decoupled from drive motions of the drive frame. Such devices may be included in a mobile device, such as a mobile display device.
1. A gyroscope, comprising:
a central anchor;
a sense frame disposed around the central anchor;
a plurality of sense beams configured for connecting the sense frame to the central anchor;
a drive frame disposed around and coupled to the sense frame, the drive frame including a first side and a second side;
pairs of drive beams disposed on opposing sides of the sense frame, the drive beams configured to drive the first side of the drive frame in a first direction along a first axis substantially in the plane of the drive frame, the drive beams being further configured to drive the second side of the drive frame in a second and opposing direction along the first axis;
a drive frame suspension configured to substantially restrict a drive motion of the drive frame to that of a substantially linear displacement along the first axis, wherein the drive frame suspension includes a plurality of flexures, each flexure of the plurality of flexures configured for coupling a pair of drive beams to the drive frame; and
a sense frame suspension configured to be compliant to rotation around a second axis orthogonal to the first axis, the sense frame suspension configured to resist translational motion along the first axis.
2. The gyroscope of claim 1 , wherein the sense frame is substantially decoupled from drive motions of the drive frame.
3. The gyroscope of claim 1 , wherein the plurality of flexures is configured for coupling the sense frame to the drive frame.
4. The gyroscope of claim 1 , wherein the sense frame suspension includes a plurality of slots between the central anchor and the sense frame.
5. The gyroscope of claim 1 , wherein the plurality of sense beams includes a first pair of sense beams extending from a first side of the central anchor along the first axis and a second pair of sense beams extending from a second side of the central anchor along a second axis substantially perpendicular to the first axis, the second side of the central anchor being adjacent to the first side of the central anchor.
6. The gyroscope of claim 1 , further including an array of electrostatic actuators configured to tune a resonant frequency of drive frame motion.
7. The gyroscope of claim 1 , wherein the drive frame includes a plurality of slots formed along an axis that is substantially perpendicular to the first axis.
8. The gyroscope of claim 1 , wherein the drive beams and the sense beams include a piezoelectric layer.
9. The gyroscope of claim 1 , wherein at least one of the sense frame and the drive frame are formed, at least in part, from plated metal.
10. The gyroscope of claim 5 , wherein the sense frame suspension includes a slot extending:
along a first sense beam of the first pair of sense beams;
along the central anchor to the second pair of sense beams; and
along a second sense beam of the second pair of sense beams.
11. The gyroscope of claim 1 , wherein the pairs of drive beams are disposed along a second axis that is substantially perpendicular to the first axis.
12. The gyroscope of claim 1 , wherein the drive beams are configured to be actuated by applying anti-phase voltages to each pair of drive beams.
13. The gyroscope of claim 6 , wherein the array of electrostatic actuators is configured to suppress quadrature coupling from the drive frame to the sense frame.
14. A gyroscope, comprising:
a central anchor;
a sense frame disposed around the central anchor;
sense beam means for detecting a sense motion of the gyroscope and for connecting the sense frame to the central anchor;
a drive frame disposed around and coupled to the sense frame, the drive frame including a first side and a second side;
drive means for driving the first side of the drive frame in a first direction along a first axis in the plane of the drive frame and for driving a second side of the drive frame in a second and opposing direction along the first axis, the drive means including pairs of drive beams disposed on opposing sides of the sense frame;
drive frame suspension means for substantially restricting a drive motion of the drive frame to that of a substantially linear displacement along the first axis, wherein the drive frame suspension means includes a plurality of flexures, each flexure being configured for coupling a pair of drive beams to the drive frame; and
sense frame suspension means for allowing rotation around a second axis orthogonal to the first axis and for resisting translational motion along the first axis.
15. The gyroscope of claim 14 , wherein the sense frame is substantially decoupled from drive motions of the drive frame.