Electrostatic microactuator with electrically isolated movable portion and associated drive circuitry
First Claim
1. A disk drive comprising:
- a magnetic recording disk having a plurality of data tracks;
a read/write head for reading data from and writing data to the disk;
a primary actuator for coarse positioning the head over a selected track; and
an electrostatic secondary actuator connected to the head and the primary actuator for fine positioning the head over the selected track, the secondary actuator comprising;
a substrate attached to the primary actuator;
a plurality of electrically conductive stationary electrodes formed on the substrate; and
a movable member formed of electrically conductive material and having (a) a frame connected to the substrate and supporting the head, and (b) a plurality of electrically conductive movable electrodes, the frame and supported head being connected to but electrically isolated from the movable electrodes.
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Accused Products
Abstract
A bidirectional electrostatic rotary microactuator has two sets of fixed electrodes, one set for driving the microactuator counterclockwise and the other set for driving it clockwise, and a rotatable frame that has movable electrodes attached to its outer wall and interleaved between the fixed electrodes. A layer of insulating material is located between the outer wall to which the movable electrodes are attached and the remainder of the frame so that the movable electrodes are electrically isolated. The frame is maintained at ground electrical potential and the movable electrodes at a fixed non-zero electrical potential. The microactuator is driven by applying a plus or minus voltage to one set of fixed electrodes and the opposite voltage to the other set, while maintaining the movable electrodes at a fixed non-zero voltage. The microactuator is usable as a secondary actuator in a disk drive for fine positioning the read/write head.
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Citations
23 Claims
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1. A disk drive comprising:
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a magnetic recording disk having a plurality of data tracks;
a read/write head for reading data from and writing data to the disk;
a primary actuator for coarse positioning the head over a selected track; and
an electrostatic secondary actuator connected to the head and the primary actuator for fine positioning the head over the selected track, the secondary actuator comprising;
a substrate attached to the primary actuator;
a plurality of electrically conductive stationary electrodes formed on the substrate; and
a movable member formed of electrically conductive material and having (a) a frame connected to the substrate and supporting the head, and (b) a plurality of electrically conductive movable electrodes, the frame and supported head being connected to but electrically isolated from the movable electrodes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A disk drive comprising:
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a base;
a rotatable magnetic recording disk mounted to the base and having a plurality of data tracks;
a read/write head for reading data from and writing data to the disk;
a head carrier for supporting the head near the surface of the disk;
a primary rotary actuator mounted to the base;
an arm having one end attached to the primary rotary actuator;
an electrostatic secondary rotary actuator attached to the other end of said arm and supporting the head carrier, the secondary rotary actuator comprising (a) a substrate attached to said other end of said arm;
(b) first and second sets of spaced apart electrically conductive stationary electrode branches fixed on said substrate;
(c) a central post fixed on the substrate;
(d) a plurality of flexible spring elements extending laterally from the post;
(e) an electrically conductive frame attached to the ends of the spring elements and rotatable about said post, said frame supporting said head carrier and having first and second side walls facing respective first and second sets of stationary branches;
(f) electrically insulating material attached to said first and second side walls; and
(g) a plurality of electrically conductive movable electrode branches attached to the electrically insulating material on said first side wall and interleaved in the spacings between the stationary branches of the first and second stationary sets; and
electrical driver circuitry responsive to a control signal and coupled to the secondary rotary actuator for providing a voltage to each of the first and second sets of stationary branches in a range between +V and −
V volts and for maintaining the movable branches at a fixed non-zero electrical potential, the electrically conductive frame being maintained at electrical ground potential as a result of its electrical isolation by said electrically insulating material. - View Dependent Claims (15, 16, 17, 18, 19, 20, 22, 23)
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21. A rotary electrostatic microactuator comprising:
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a substrate having an electrically insulating surface;
first and second sets of spaced apart electrically conductive fixed electrode branches fixed on said insulating substrate surface;
a central post fixed on said insulating substrate surface;
a plurality of flexible spring elements extending laterally from the post;
an electrically conductive frame attached to the ends of the spring elements and rotatable about said post, said frame having inner and outer walls;
electrically insulating material attached to said inner and outer walls and electrically isolating the inner wall from the outer wall;
a plurality of spaced apart electrically conductive movable electrode branches attached to the outer wall and interleaved in the spacings between the fixed electrode branches;
whereby the movable electrode branches are connected to but electrically isolated from the electrically conductive rotatable frame.
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Specification