IPC분류정보
| 국가/구분 |
United States(US) Patent
등록
|
| 국제특허분류(IPC7판) |
|
| 출원번호 |
US-0620120
(2015-02-11)
|
| 등록번호 |
US-9070394
(2015-06-30)
|
|
발명자
/ 주소 |
- Hahn, Peter
- Ee, Kuen Chee
- Dunn, Christopher
|
| 출원인 / 주소 |
|
| 대리인 / 주소 |
Intellectual Property Law Offices of Joel Voelzke, APC
|
| 인용정보 |
피인용 횟수 :
6 인용 특허 :
46 |
초록
▼
A PZT microactuator such as for a hard disk drive has a restraining layer on its side that is opposite the side on which the PZT is mounted. The restraining layer is a stiff material. The restraining layer reduces bending of the PZT as mounted and hence increases effective stroke length, or reverses
A PZT microactuator such as for a hard disk drive has a restraining layer on its side that is opposite the side on which the PZT is mounted. The restraining layer is a stiff material. 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. For simplicity of construction and assembly to the suspension, the PZT microactuator may be a multi-layer PZT with the top layer being unpoled or otherwise inactive PZT material, and having a wrap-around electrode so that the microactuator can be mechanically and electrically bonded to the suspension using a single adhesive dispense and cure step.
대표청구항
▼
1. A dual stage actuated suspension for a hard disk drive, the suspension comprising: a beam supporting a read/write head at a distal end thereof for writing data to, and reading data from, a data disk; anda microactuator assembly for effecting fine positional movements of the read/write head, the m
1. A dual stage actuated suspension for a hard disk drive, the suspension comprising: a beam supporting a read/write head at a distal end thereof for writing data to, and reading data from, a data disk; anda microactuator assembly for effecting fine positional movements of the read/write head, the microactuator assembly having a top side, a bottom side, and at least a first end, the microactuator assembly being affixed to the suspension at its bottom side, the microactuator assembly comprising: a first layer comprising a single active piezoelectric layer, the first layer having a bottom face thereof;a first electrode disposed on the first layer;a second electrode having at least a bottom electrode portion disposed on the bottom face of the first layer; anda second layer on the first electrode, the second layer comprising a stiff material, the second layer acting as a constraining layer to constrain expansion or contraction of the first layer when the first layer is activated by application of a voltage across the first and second electrodes;the first electrode having a wrap-around portion that extends onto at least one of the first end of the microactuator assembly, the top side of the microactuator assembly, and the bottom side of the microactuator assembly;wherein the constraining layer comprises unpoled piezoelectric material. 2. The suspension of claim 1 wherein the constraining layer comprises a single layer of inactive piezoelectric material. 3. The suspension of claim 1 wherein both a driving voltage and a ground are supplied to said electrodes at the microactuator assembly's bottom side. 4. The suspension of claim 1 wherein conductive adhesive mechanically and electrically bonds the electrodes at the microactuator's bottom side. 5. A dual stage actuated suspension for a hard disk drive, the suspension comprising: a beam supporting a read/write head at a distal end thereof for writing data to, and reading data from, a data disk; anda microactuator assembly for effecting fine positional movements of the read/write head, the microactuator assembly comprising: a first ceramic layer comprising piezoelectric material, the first ceramic layer being bonded at a bottom side thereof to the suspension;a second ceramic layer comprising piezoelectric material, the second ceramic layer being disposed on the first ceramic layer; andfirst and second electrodes comprising respective conductive layers, the first and second electrodes being arranged such that when a voltage is applied across the electrodes: a first region of the first ceramic layer expands or contracts, said first region defining a piezoelectrically active region of the first ceramic layer; anda second region of the first ceramic layer substantially does not expand or contract, the second region defining a piezoelectrically inactive region of the first ceramic layer;wherein:the second ceramic layer has a greater horizontal extent than does the piezoelectrically active region;when a voltage is applied across the first and second electrodes, the second layer substantially does not expand or contract as does the piezoelectrically active region of the first layer, such that the second layer acts as a constraining layer to resist expansion or contract of the first layer; andboth the first and second electrodes are electrically accessible from a bottom surface of the microactuator assembly, the first electrode extending between the first and second layers and to said bottom surface, the microactuator assembly being electrically connected to ground and to a driving voltage source at said bottom surface. 6. The suspension of claim 5 wherein the piezoelectrically inactive region comprises unpoled piezoelectric material. 7. The suspension of claim 5 wherein the first electrode extends on a top and a bottom of the piezoelectrically inactive region of the first layer, and a side thereof. 8. A dual stage actuated suspension for a hard disk drive, the suspension comprising: a beam supporting a read/write head at a distal end thereof for writing data to, and reading data from, a data disk; anda microactuator assembly for effecting fine positional movements of the read/write head, the microactuator assembly comprising: a first piezoelectric layer having a horizontal extent thereof, the first piezoelectric layer being bonded at a bottom side thereof to the suspension, said bottom side defining a bottom face of the microactuator assembly;a second piezoelectric layer disposed over the first piezoelectric layer, the second piezoelectric layer having a horizontal extent thereof;a first electrode comprising: a first conductive layer disposed between the first and second piezoelectric layers, the first conductive layer having a horizontal extent thereof that is substantially coextensive with the horizontal extents of the first and second piezoelectric layers;a wrap-around portion suitable for making an electrical connection thereto, comprising at least one of an end portion on an end of the microactuator assembly, a bottom portion on said bottom face of the microactuator assembly, and a top portion on a top face of the microactuator assembly;a second electrode comprising a second conductive layer extending over a majority of said bottom face of the microactuator assembly;wherein:when a voltage is applied across the first and second electrodes, the second piezoelectric layer substantially does not expand or contract as does the first piezoelectric layer, such that the second layer acts as a constraining layer to resist expansion or contract of the first layer. 9. The suspension of claim 8 wherein the first piezoelectric layer includes: an active piezoelectric region that is disposed between the first and second electrodes, such that a voltage across the first and second electrodes produces an electric field therethrough and produces piezoelectric expansion or contraction thereof;an inactive piezoelectric region that is not disposed between the first and second electrodes, such that a voltage across the first and second electrodes does not produce a significant electric field therethrough and therefore does not produce a significant piezoelectric expansion or contraction thereof. 10. The suspension of claim 9 wherein the first electrode at least partially wraps around to a top and a bottom of the inactive piezoelectric region. 11. The suspension of claim 8 wherein the first electrode has a portion that substantially covers the first piezoelectric layer. 12. The suspension of claim 8 wherein the first piezoelectric layer does not have an electrode over a majority thereof. 13. A dual stage actuated suspension for a disk drive, the suspension having: a piezoelectric microactuator having top and bottom sides, at least a portion of a bottom side being bonded to the suspension at first and second ends thereof, the first and second ends spanning a gap between respective portions of the suspension, the piezoelectric microactuator and the suspension being configured so that actuation of the microactuator changes the distance of the gap to produce fine movements of a read/write head mounted to the suspension;the microactuator comprising: a poled piezoelectric material, the poled piezoelectric material having opposite first and second faces;a first electrode extending over the poled piezoelectric material, the first electrode also being electrically connected to at least one of a bottom side of the microactuator and an end of the microactuator;a restraining layer affixed to the first electrode above the second face of the poled piezoelectric material such that the first electrode is sandwiched between the poled piezoelectric material and the restraining layer, the restraining layer comprising the same material as said piezoelectric material but being unpoled;a second electrode extending on the bottom side of the microactuator, such that the microactuator can be activated by applying a voltage across the second electrode on the bottom side of the microactuator and the first electrode on said at least one of said bottom side of the piezoelectric microactuator and said end of the microactuator;wherein the restraining layer alters the bending behavior of the microactuator so as to increase the effective stroke length of the microactuator compared to what the stroke length of the microactuator would be in the absence of the restraining layer. 14. The suspension of claim 13 wherein the first electrode substantially completely covers the poled piezoelectric material. 15. The suspension of claim 13 wherein the first electrode is electrically connected to the bottom side of the microactuator, such that the microactuator can be activated by applying a voltage across the first and second electrodes on the bottom side of the microactuator. 16. The suspension of claim 13 wherein a majority of a top side of the restraining layer is uncovered by metallization. 17. The suspension of claim 13 wherein the poled piezoelectric material is integrally formed as a sheet of ceramic material, and the ceramic was poled such that a first part thereof is now poled piezoelectric material and a second part thereof remains substantially unpoled. 18. The suspension of claim 17 wherein the first electrode extends to at least one of an end of the second and unpoled part of the ceramic material and a bottom side of the ceramic material. 19. The suspension of claim 18 wherein: the first electrode extends over at least a portion of the bottom side of the ceramic material on the bottom side of the microactuator, such that the microactuator can be activated by applying a voltage across the first and second electrodes on the bottom side thereof.
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