1. A gyroscope, comprising:
a drive frame;
a central anchor;
a plurality of drive beams disposed on opposing sides of the central anchor, the drive beams connecting the drive frame to the central anchor, each of the drive beams including a piezoelectric layer and configured to cause the drive frame to oscillate torsionally in a plane of the drive beams;
a proof mass; and
a plurality of sense beams including a layer of piezoelectric sense electrodes, the sense beams configured for connecting the drive frame to the proof mass, the sense beams being configured to bend in a sense plane substantially perpendicular to the plane of the drive beams in response to an applied angular rotation, causing a piezoelectric charge in the sense electrodes.
2. The gyroscope of claim 1, wherein the plurality of drive beams is further configured to constrain the drive frame to rotate substantially in the plane of the drive beams.
3. The gyroscope of claim 1, wherein the plurality of drive beams includes a first pair of drive beams disposed on a first side of the central anchor and a second pair of drive beams disposed on an opposing side of the central anchor.
4. The gyroscope of claim 1, wherein the drive frame is disposed within the proof mass.
5. The gyroscope of claim 1, wherein the sense beams are configured to bend in the sense plane in response to sense motion of the proof mass.
6. The gyroscope of claim 1, wherein the sense beams are loaded due to forces exerted by the drive beams.
7. The gyroscope of claim 1, wherein the sense beams are tapered sense beams having a width that decreases with increasing distance from the anchor.
8. The gyroscope of claim 1, wherein the proof mass is formed, at least in part, from plated metal.
9. The gyroscope of claim 3, wherein the first pair of drive beams and the second pair of drive beams are configured to generate drive oscillations via a differential piezoelectric drive.
10. The gyroscope of claim 5, wherein the drive frame is substantially decoupled from the sense motion of the proof mass.
11. The gyroscope of claim 7, wherein bending stresses along the tapered sense beams are substantially uniform with increasing distance from the anchors when the gyroscope is operating in a sense mode.
12. A gyroscope, comprising:
drive frame means;
a substrate;
anchor means connected to the substrate and disposed within the drive frame means;
drive means for connecting the drive frame means to the anchor means, the drive means configured to cause the drive frame means to oscillate torsionally in a plane of the drive means, the drive means being further configured to constrain the drive frame means to rotate substantially in the plane of the drive means;
proof mass means disposed around the drive means, the proof mass means configured for sense motions wherein the proof mass means bends in a sense plane in response to an applied angular rotation, the sense plane being substantially perpendicular to the plane of the drive means, the sense motions of the proof mass means being substantially decoupled from motions of the drive frame means; and
sense means for connecting the drive means to the proof mass means, the sense motions of the proof mass means causing a piezoelectric charge in the sense means.
13. The gyroscope of claim 12, wherein the drive means includes a first pair of drive beams disposed on a first side of the anchor means and a second pair of drive beams disposed on an opposing side of the anchor means.
14. The gyroscope of claim 12, the sense means being further configured to bend in the sense plane in response to the sense motions of the proof mass means.
15. The gyroscope of claim 12, wherein forces exerted by the drive means axially load the sense means.
16. A method of fabricating a gyroscope, the method comprising:
depositing electrodes on a substrate;
forming an anchor on the substrate;
forming a drive frame on the anchor;
forming pairs of drive beams on opposing sides of the anchor, the drive beams connecting the drive frame to the anchor, the drive beams being configured to constrain the drive frame to rotate substantially in the plane of the drive beams;
forming a proof mass around the drive frame; and
forming a plurality of sense beams that connect the drive frame to the proof mass, the sense beams being configured to allow sense motions of the proof mass in a sense plane substantially perpendicular to the plane of the drive beams in response to an applied angular rotation, the sense beams being configured to substantially decouple the sense motions of the proof mass means from motions of the drive frame.
17. The method of claim 16, wherein forming the drive beams includes the following:
depositing a first metal layer that is in contact with the electrodes;
depositing a piezoelectric layer on the first metal layer;
depositing a second metal layer on the piezoelectric layer; and
electroplating a third metal layer on the second metal layer.
18. The method of claim 16, wherein the process of forming the anchor includes:
etching through a sacrificial layer to expose the first metal layer;
depositing an oxide layer on the first metal layer;
forming a seed layer on the oxide layer; and
electroplating the third metal layer on the seed layer.
19. The method of claim 16, wherein forming the proof mass and forming the drive frame include:
etching between a drive frame area and a proof mass area;
depositing high aspect ratio photoresist material between the drive frame area and the proof mass area; and
electroplating the third metal layer in the drive frame area and the proof mass area.
20. The method of claim 16, further including separating the substrate into a plurality of sub-panels prior to the electroplating.
21. The method of claim 19, wherein forming the proof mass and forming the drive frame also includes:
removing the high aspect ratio photoresist material from between the drive frame area and the proof mass area;
etching to expose a sacrificial layer disposed below the drive frame and the proof mass; and
removing the sacrificial layer to release the drive frame and the proof mass.
22. A gyroscope, comprising:
a central anchor;
a proof mass disposed around the central anchor, the proof mass having a first end and a second end;
a first drive beam connecting a first side of the central anchor to the first end of the proof mass;
a second drive beam connecting a second side of the central anchor to the second end of the proof mass;
a first pair of piezoelectric drive electrodes disposed on the first drive beam;
a second pair of piezoelectric drive electrodes disposed on the second drive beam;
a first piezoelectric sense electrode disposed on the first drive beam; and
a second piezoelectric sense electrode disposed on the second drive beam,
wherein the first pair and the second pair of piezoelectric drive electrodes are configured, via a differential piezoelectric drive, to cause the proof mass to oscillate torsionally in a plane of the drive beams, and
wherein the proof mass is configured for sense motions wherein the proof mass means bends in a sense plane in response to an applied angular rotation, the sense plane being substantially perpendicular to the plane of the drive beams, the sense motions of the proof mass causing a piezoelectric charge in the sense electrodes.
23. The gyroscope of claim 22, wherein each of the piezoelectric drive electrodes and the piezoelectric sense electrodes include a piezoelectric film.
24. The gyroscope of claim 22, wherein the proof mass is formed, at least in part, from plated metal.
25. The gyroscope of claim 22, wherein at least one of the first drive beam and the second drive beam include a central slot.
26. The gyroscope of claim 25, wherein the pairs of drive electrodes are disposed on opposite sides of the central slot.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of making a series of N resonant frequency tags, N being an integer greater than 1, with each of the N tags having a resonant frequency which differs from the resonant frequency of every other tag in the series by at least a predetermined minimum frequency range, the method comprising the steps of:
(a) forming N first conductive patterns, the first conductive patterns all being substantially the same and each first conductive pattern comprising an inductive element and a first land with a first end of the first land being connected to one end of the inductive element and a second end of the first land being spaced from the first end by a predetermined distance;
(b) separately forming N second conductive patterns, the second conductive patterns all being substantially the same and each second conductive pattern comprising a second land and a link element, the second land having a predetermined width; and
(c) sequentially securing a second conductive pattern to each of the first conductive patterns at a location so that the second land of each second conductive pattern overlies a portion of the first land of the corresponding first conductive pattern with a dielectric therebetween to establish the plates of a capacitive element for each resonant frequency tag, the location of each second conductive pattern relative to the first land of a corresponding first conductive pattern and thus the amount by which each second overlies the first land being different for each resonant frequency tag of the series so that the capacitance of the capacitive element of each resonant frequency tag is different from the capacitance of the capacitive element of every other resonant frequency tag of the series by at least a minimum value to thereby cause each resonant frequency tag to resonate at a different frequency from every other resonant frequency tag of the series.
2. The method as recited in claim 1, wherein each first land has a width which decreases when moving along the length from one end to the other end.
3. The method as recited in claim 1, wherein each second conductive pattern is secured to the corresponding first conductive pattern by one of an adhesive and hot pressing.
4. The method as recited in claim 3, wherein each second conductive pattern is secured to the corresponding first conductive pattern by applying pressure, the amount of pressure being varied to control the resonant frequency of the tag.
5. The method as recited in claim 1, wherein the second conductive pattern, once formed, is initially held of a carrier sheet.
6. The method as recited in claim 1, wherein the second conductive pattern comprise said dielectric layer which is placed between the second land and the first land prior to securing the second conductive pattern to the substrate.