Multi-layer PZT microacuator with active PZT constraining layers for a DSA suspension

Patent metadata

Field	Value
Publication number	US-11205449-B2
Application number	US-202016857133-A
Country	US
Kind code	B2
Filing date	Apr 23, 2020
Priority date	Mar 18, 2013
Publication date	Dec 21, 2021
Grant date	Dec 21, 2021

Abstract

A PZT microactuator such as for a hard disk drive has a restraining layer bonded on its side that is opposite the side on which the PZT is mounted. The restraining layer comprises a stiff and resilient material such as stainless steel. The restraining layer can cover most or all of the top of the PZT, with an electrical connection being made to the PZT where it is not covered by the restraining layer. The restraining layer reduces bending of the PZT as mounted and hence increases effective stroke length, or reverses the sign of the bending which increases the effective stroke length of the PZT even further. The restraining layer can be one or more active layers of PZT material that act in the opposite direction as the main PZT layer. The restraining layer(s) may be thinner than the main PZT layer.

First claim

We claim:

1. A microactuator assembly, the microactuator assembly comprising:
at least one PZT element including a first longitudinal side and an opposing second longitudinal side;
a first electrode on a first surface of the microactuator assembly extending from the first longitudinal side to the second longitudinal side of the of the microactuator assembly, the first electrode having a first width expanding a full length of the first longitudinal side of the at least one PZT element; and
a second electrode on a second surface of the microactuator assembly, opposite the first surface of the microactuator assembly and extending from the first longitudinal side to the second longitudinal side of the at least one PZT element, the second electrode includes a second width extending from the first longitudinal side and is less than the width of the first electrode, the second electrode is configured to counteract the first electrode constraint exerted by a piezoelectric bonding adhesive.

2. The microactuator assembly of claim 1 , wherein the first and second electrodes are electrically ganged by conductive adhesive that bonds the microactuator assembly to a surface on a device.

3. The microactuator assembly of claim 1 , wherein the at least one PZT element is a plurality of PZT elements disposed between the first electrode and the second electrode.

4. The microactuator assembly of claim 1 , wherein the width of the second electrode is variable along a longitudinal axis of the second electrode.

5. The microactuator assembly of claim 4 , wherein the second electrode is configured to expose at least two sections of the at least one PZT element.

6. The microactuator assembly of claim 4 , wherein the second electrode is configured to expose one section of the at least one PZT element.

7. The microactuator assembly of claim 1 , wherein the width of the second electrode is variable along a latitudinal axis of the second electrode.

8. The microactuator assembly of claim 7 , wherein the second electrode is configured to expose at least two sections of the at least one PZT element.

9. The microactuator assembly of claim 7 , wherein the second electrode is configured to expose one section of the at least one PZT element.

10. The microactuator assembly of claim 1 , wherein the second electrode includes at least one exposed portion.

11. The microactuator assembly of claim 10 , wherein the second electrode is configured to have a distal portion, a proximal portion, and a coupling portion connecting the distal portion and the proximal portion.

12. The microactuator assembly of claim 10 , wherein the at least one exposed portion is a plurality of exposed portions.

13. A suspension for a disk drive, the suspension comprising:
a microactuator assembly including:
at least one PZT element including a first longitudinal side and an opposing second longitudinal side,
a first electrode on a first surface of the microactuator assembly extending from the first longitudinal side to the second longitudinal side of the of the microactuator assembly, the first electrode having a first width expanding a full length of the first longitudinal side of the at least one PZT element, and
a second electrode on a second surface of the microactuator assembly opposite the first surface of the microactuator assembly and extending from the first longitudinal side to the second longitudinal side of the at least one PZT element, the second electrode includes a second width extending from the first longitudinal side and is less than the width of the first electrode, the second electrode is configured to counteract the first electrode constraint exerted by a piezoelectric bonding adhesive.

14. The suspension of claim 13 , wherein the at least one PZT element is a plurality of PZT elements disposed between the first electrode and the second electrode.

15. The suspension of claim 13 , wherein the width of the second electrode is variable along a longitudinal axis of the second electrode.

16. The suspension of claim 15 , wherein the second electrode is configured to expose at least two sections of the at least one PZT element.

17. The suspension of claim 15 , wherein the second electrode is configured to expose one section of the at least one PZT element.

18. The suspension of claim 13 , wherein the width of the second electrode is variable along a latitudinal axis of the second electrode.

19. The suspension of claim 18 , wherein the second electrode is configured to expose at least two sections of the at least one PZT element.

20. The suspension of claim 18 , wherein the second electrode is configured to expose one section of the at least one PZT element.

21. The suspension of claim 13 , wherein the second electrode includes at least one exposed portion.

22. The suspension of claim 21 , wherein the second electrode is configured to have a distal portion, a proximal portion, and a coupling portion connecting the distal portion and the proximal portion.

23. The suspension of claim 21 , wherein the at least one exposed portion is a plurality of exposed portions.

Assignees

• Magnecomp Corp

Inventors

• Glaess David
• Ee Kuen Chee
• Zhang Long
• Dunn Chris

Classifications

• G11B5/4806

  specially adapted for disk drive assemblies, e.g. assembly prior to operation, hard or flexible disk drives (G11B5/488 - G11B5/54 take precedence) · CPC title

• G11B5/596

  for track following on disks {(G11B5/5526, G11B5/5552, G11B5/5565, G11B5/5582 take precedence)} · CPC title

• G11B5/5552

  using fine positioning means for track acquisition separate from the coarse (e.g. track changing) positioning means · CPC title

• G11B5/4873 Primary

  the arm comprising piezoelectric or other actuators for adjustment of the arm · CPC title

• G11B5/483

  Piezoelectric devices between head and arm, e.g. for fine adjustment · CPC title