Dynamic magnetic information storage or retrieval – Head mounting – For adjusting head position
Reexamination Certificate
1999-07-22
2001-11-20
Cao, Allen (Department: 2754)
Dynamic magnetic information storage or retrieval
Head mounting
For adjusting head position
Reexamination Certificate
active
06320730
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a disc drive microactuator, and more particularly to a high resolution head positioning mechanism that includes a lowstress microactuator cradle for improving the stroke and torsional gain characteristics of the microactuator.
The density of concentric data tracks on magnetic discs continues to increase (that is, the width of data tracks and radial spacing between data tracks are decreasing), requiring more precise radial positioning of the head. Conventionally, head positioning is accomplished by operating an actuator arm with a large-scale actuation motor, such as a voice coil motor, to radially position a head on a flexure at the end of the actuator arm. The large-scale motor lacks sufficient resolution to effectively accommodate high track-density discs. Thus, a high resolution head positioning mechanism, or microactuator, is necessary to accommodate the more densely spaced tracks.
One promising design for high resolution head positioning involves employing a high resolution microactuator in addition to the conventional lower resolution actuator motor, thereby effecting head positioning through dual-stage actuation. Various microactuator designs have been considered to accomplish high resolution head positioning. One such design is disclosed in U.S. application Ser. No. 09/289,024 filed Apr. 9, 1999 for “Unitary Synchronous Flexure Microactuator” by R. Kant and F. M. Stefansky, which is hereby incorporated by reference. This design includes a microactuator cradle that carries the entire micro-electronic machine (MEM) that supports the slider and generates high resolution displacement of the slider. The microactuator cradle is mounted a load beam connected to an actuator arm for coarsely positioning and supporting the entire cradle and slider structure over the surface of a disc. There is a continuing need in the art for improved microactuator designs such as the one disclosed in the aforementioned application, to achieve desired characteristics for operation in a disc drive system.
BRIEF SUMMARY OF THE INVENTION
The present invention is a dual-stage actuation assembly for use in a disc drive having a recording disc rotatable about an axis, and a slider supporting a transducing head for transducing data with the disc. The dual-stage actuation assembly supports the slider to position the transducing head adjacent a selected radial track of the disc, and includes a movable actuator arm and a load beam connected to the actuator arm. A microactuator is attached to the load beam, and includes a pad for attachment to the load beam and a hinge extending from the pad. A microactuator cradle is attached to the hinge to support the slider, and includes a slider support structure having first and second beams in a plane generally normal to a surface of the disc and a gimbal attached to the slider. A first piezoelectric element is coupled to the first beam and is bendable in response to control signals to bend the first beam in a selected direction. A second piezoelectric element is coupled to the second beam and is bendable in response to control signals to bend the second beam in the selected direction. Bending of the first and second beams causes rotational displacement of the microactuator cradle with respect to the pad about the hinge, thereby altering the position of the slider with respect to the tracks of the disc.
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Kant Rishi
Stefansky Frederick Mark
Cao Allen
Kinney & Lange , P.A.
Seagate Technology LLC
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