Piezoelectric micro-actuator for magnetic tape read/write head
View Patent ↗The claimed embodiments provide methods, apparatuses and systems directed to a servo-actuated positioner for a read/write head that uses a piezoelectric super fine actuator that moves the read/write head to maintain alignment with data tracks on a magnetic tape. The servo-actuated positioner, in one implementation, uses flexures to mechanically support the read/write head. Piezoelectric elements are attached to the flexures in strategic locations to effect movement of the read/write head when the elements are actuated. This configuration achieves a large actuator motion using small piezoelectric elements. Additionally, manufacturability is improved since the piezoelectric elements, which are typically brittle, are attached to the mechanically robust flexures.
1. An actuator assembly, for use in a tape drive, comprising:
a head carriage;
a head movably attached at opposite distal ends thereof to the head carriage by first and second flexures;
a fine actuator operative to move the head carriage in a direction substantially perpendicular to a media travel path;
a coarse actuator operative to move the fine actuator in the direction substantially perpendicular to the media the media travel path;
a super-fine actuator operative to move the head in the direction substantially perpendicular to the media travel path;
control logic operative to process servo-based control signals transduced by the head from a data recording medium to separately control the fine actuator and the super-fine actuator to orient the head relative to the data recording medium; and
wherein the super-fine actuator comprises one or more piezoelectric elements attached to the first flexure.
2. The actuator assembly as recited in claim 1 wherein the super-fine actuator further comprises one or more piezoelectric elements attached to the second flexure.
3. The actuator assembly as recited in claim 1 wherein the one or more piezoelectric elements are monomorph piezoelectric elements.
4. An actuator assembly, for use in a tape drive, comprising:
a coarse actuator operative to move a read/write head in a direction substantially perpendicular to a magnetic tape travel path;
a fine actuator operative to move the read/write head in the direction substantially perpendicular to the magnetic tape travel path;
one or more flexures coupling the fine actuator to the coarse actuator;
a super-fine actuator operative to move the read/write head in the direction substantially perpendicular to the magnetic tape travel path;
control logic operative to process servo-based control signals transduced by the read/write head from a magnetic tape to separately control the fine actuator and the super-fine actuator to orient the read/write head relative to the magnetic tape; and
wherein the super-fine actuator comprises one or more piezoelectric elements disposed on the one or more flexures and operative, when actuated, to displace the flexures and the read/write head.
5. The actuator assembly as recited in claim 4 wherein the one or more flexures are first and second flexures and wherein the one or more piezoelectric elements are first and second pairs of piezoelectric elements, the first pair disposed on the first flexure and the second pair disposed on the second flexure.
6. The actuator assembly as recited in claim 5 wherein the first and second pairs of piezoelectric elements are first and second pairs of monomorph piezoelectric elements.
7. The actuator assembly as recited in claim 4 wherein the one or more flexures are each angled to form a cavity between the one or more flexures and the one or more piezoelectric elements.
8. The actuator assembly as recited in claim 7 wherein the cavity is generally triangle-shaped.
9. The actuator assembly as recited in claim 8 wherein the one or more flexures are first and second flexures and wherein the one or more piezoelectric elements are first and second pairs of piezoelectric elements, the first pair disposed on the first flexure and the second pair disposed on the second flexure.
10. The actuator assembly as recited in claim 9 wherein zeniths of the generally triangle-shaped cavities of the first flexure faces corresponding zeniths of the triangle shaped cavities of the second flexure.
11. The actuator assembly as recited in claim 10 wherein the first and second pairs of piezoelectric elements are first and second pairs of monomorph piezoelectric elements.
12. An actuator assembly, for use in a tape drive, comprising:
a head carriage;
a head movably attached at opposite distal ends thereof to the head carriage by first and second piezoelectric elements, wherein the first and second piezoelectric elements are disposed to move the head relative to the head carriage in response to electric signals;
a fine actuator operative to move the head carriage in a direction substantially perpendicular to a travel path of a recording medium;
a coarse actuator operative to move the fine actuator in the direction substantially perpendicular to the travel path;
control logic operative to process servo-based control signals transduced by the head from a recording medium to separately control the fine actuator and first and second piezo-electric elements to orient the head relative to the recording medium.
13. The actuator assembly as recited in claim 12 wherein the first and second piezoelectric elements are bimorph piezoelectric elements.