Piezoelectric actuator head suspension unit employing piezoelectric actuator, and magnetic disk drive employing head suspension unit
View Patent ↗A piezoelectric element of a piezoelectric actuator is clamped by two electrodes, each of which has a conductive layer on a insulating layer. At least a connection terminal is formed by extending the conductive layer outside the insulating layer.
1. A piezoelectric actuator comprising:
a piezoelectric element; and
first and second electrodes clamping said piezoelectric element, wherein:
said first electrode includes an insulating layer, a first conducting layer formed on said insulating layer and brought into contact with one side of said piezoelectric element, and a second conducting layer isolated from said first conducting layer;
said first conducting layer has a first connection terminal projecting from an edge of said insulating layer;
said second conducting layer has second and third connection terminals projecting from the edge of said insulating layer; and
said first and second connection terminals constitute a pair of terminal electrodes, and said third connection terminal is connected to said second electrode.
2. A piezoelectric actuator according to claim 1 , wherein said second electrode has a connector opposed to said third connection terminal.
3. A piezoelectric actuator according to claim 1 , wherein said connection terminals are coated with Au.
4. A piezoelectric actuator according to claim 1 , further comprising a wiring member connected to a power supply, wherein said pair of terminal electrodes is attached to said wiring member.
5. A piezoelectric actuator according to claim 4 , wherein said wiring member is a flexible printed-circuit board.
6. A piezoelectric actuator according to claim 1 , wherein said piezoelectric element is polarized in a direction perpendicular to a direction in which a voltage is applied, and makes a shear strain with application of the voltage.
7. A piezoelectric actuator according to claim 6 , wherein said piezoelectric element and other piezoelectric element that is polarized in a direction opposite to the direction in which said piezoelectric element is polarized and that makes a shear strain with application of a voltage are juxtaposed.
8. A piezoelectric actuator according to claim 1 , wherein said first electrode further comprises an SUS layer and said second electrode comprises an SUS layer, an insulating layer, and a conducting layers and said conducting layer of said second electrode having connection terminal projecting from the edge of said SUS layer and said insulating layer of said second electrode.
9. A head suspension unit comprising a head suspension that includes a magnetic head, a base fixed to a carriage arm, and a movable member that bears said head suspension, and having a piezoelectric actuator clamped by said base and said movable member so that said suspension can be inched, wherein:
a piezoelectric actuator set forth in claim 1 is adopted as said piezoelectric actuator.
10. A magnetic disk drive comprising a magnetic disk in which data can be stored, and a head suspension unit fixed to a carriage arm that can pivot on a predetermined shaft, wherein:
a head suspension unit set forth in claim 9 is adopted as said head suspension unit.
11. A piezoelectric actuator comprising:
a piezoelectric element; and
first and second electrodes clamping said piezoelectric element, wherein:
at least one of said first and second electrodes includes an insulating layer, and a conducting layer formed on said insulating layer and brought into contact with said piezoelectric element; and
said conducting layer has a connection terminal projecting from an edge of said insulating layer.
12. A piezoelectric actuator according to claim 11 , wherein the other of said first and second electrodes has a conducting layer brought into contact with said piezoelectric element, said conducting layer having a connection terminal projecting from the edge of said insulating layer.
13. A piezoelectric actuator according to claim 11 , wherein said connection terminal is coated with Au.
14. A piezoelectric actuator according to claim 11 , further comprising a wiring member connected to a power supply, wherein said connection terminal is attached to said wiring member.
15. A piezoelectric actuator according to claim 14 , wherein said wiring member is a flexible printed-circuit board.
16. A piezoelectric actuator according to claim 11 , wherein said piezoelectric element is polarized in a direction perpendicular to a direction in which a voltage is applied, and makes a shear strain with application of the voltage.
17. A piezoelectric actuator according to claim 16 , wherein said piezoelectric element and another piezoelectric element that is polarized in a direction opposite to the direction in which said piezoelectric element is polarized and that makes a shear strain with application of a voltage are juxtaposed.
18. A piezoelectric actuator according to claim 11 , wherein said one of first and second electrodes further comprises an SUS layer and the other of said first and second electrodes comprises an SUS layer, an insulating layer, and a conducting layer, said conducting layer of said other of said first and second electrodes having a connection terminal projecting from the edge of said SUS layer and said insulating layer of said other of said first and second electrodes.
19. A head suspension unit comprising a head suspension that includes a magnetic head, a base fixed to a carriage arm, and a movable member that bears said head suspension, and having a piezoelectric actuator clamped by said base and said movable member so that said suspension can be inched, wherein:
a piezoelectric actuator set forth in claim 11 is adopted as said piezoelectric actuator.
20. A magnetic disk drive comprising a magnetic disk in which data can be stored, and a head suspension unit fixed to a carriage arm that can pivot on a predetermined shaft, wherein:
a head suspension unit set forth in claim 19 is adopted as said head suspension unit.