Suspension microactuator with wrap-around electrode on inactive constraining layer

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;
• and
• a 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;
• and
• first 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;
• and
• a 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;
• and
• both 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.

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;
• and
• a 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.

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.