Fujitsu Corporation

Other

Yukihiro Uematsu

Tomoyoshi Yamada

Shinji Koganezawa

Tetsuya Suzuki

Keiji Aruga

Shuichi Hashimoto

Susumu Hasegawa

Ryuma Sakamoto

Hisashi Nakano

Tadayoshi Noguchi

Junichi Inoue

Nobuyuki Suzuki

Kazuhiko Takaishi

Takahiro Imamura

Hitoshi Kanai

Takeaki Shimanouchi

Ryosuke Koishi

Toru Kohei

Takahisa Ueno

A pair of slits are defined in a slider body of a head slider so as to extend from a trailing end surface to the leading end on the slider body. A movable block is established in the slider body between the slits. The slits ensure the extent of movement for the movable block. Elongated plates enable a relative displacement between the movable block and a stationary block. A head element is mounted on a trailing end surface of the movable block. The thickness of a non-magnetic layer corresponds to the gap length of the head element. The gap length of the head element can easily be controlled based on deposition of the non-magnetic layer. The thickness of the non-magnetic layer can be reduced in a relatively facilitated manner, so that the gap length of the head element can easily be minimized.

Head slider having microactuator

An actuator includes a shear-type piezoelectric element of predetermined thickness and an opposed electrode formed on two electrodes in spaced relationship on a base member. The opposed electrode is displaced in accordance with the direction of polarization of the shear-type piezoelectric element upon applying a voltage between the two electrodes. The opposed electrode thus constitutes an operating section of the actuator. The actuator can be incorporated as a part of the head actuator to constitute a head-positioning mechanism capable of displacing the head by a minuscule distance independently of the operation of the head actuator.

Actuator using piezoelectric element and head-positioning mechanism using the actuator

An actuator having a simple configuration requiring no high dimensional accuracy, high in positioning accuracy and low in cost, and a head-positioning mechanism using the actuator are disclosed. An actuator according to a first application comprises a shear-type piezoelectric element of predetermined thickness and an opposed electrode formed on two electrodes in spaced relationship on a base member. The opposed electrode is displaced in accordance with the direction of polarization of the shear-type piezoelectric element upon applying a voltage between the two electrodes. The opposed electrode thus constitutes an operating section of the actuator. An actuator according to a second application comprises a movable member arranged on a drive member including a shear-type piezoelectric element on a base member. The drive member includes a plurality of layers of piezoelectric elements polarized in alternately opposite directions perpendicular to the thickness of the devices. A plurality of conductive layers are formed adjacently to the respective layers of the devices to permit voltage application thereto. The movable member can be driven in parallel to the base member upon application of a voltage between the conductive layers. Any one of these actuators can be incorporated as a part of the head actuator to constitute a head-positioning mechanism capable of displacing the head by a minuscule distance independently of the operation of the head actuator.

Head position control is implemented in a disk drive for the case in which a disk is assembled into the disk drive after a precise track is recorded onto it using an external apparatus, which is capable of high-speed access even if there is eccentricity between a track defined by servo information and the center of rotation of the track. Two phase servo bursts consisting of servo information are recorded onto each of the servo information regions of a disk surface, in mutual alternation, the strength ratio between signals detected from these two phase servo bursts being used to determine to which side the head is displaced. By performing control so that this strength ratio is a prescribed value at each angular position, control is achieved so that the head moves along a circular path of rotation, even if there is eccentricity in the servo circular path defined by the recorded servo information with respect to the center of rotation.

Head position control for a disk drive which performs recording about

Disclosed is a head positioning control system for disk drives which enables fast access even when eccentricities of tracks defined with servo control information relative to the center of rotation are different among disks assembled after the servo control information is externally written on the respective disks. The head positioning control system is adapted to a disk drive comprising a plurality of disks each having a record surface on which servo control information indicating positions in a radial direction on a disk is recorded, and heads associated with the plurality of disk record surfaces and designed to detect information stored on the plurality of disk record surfaces. The servo control information includes position information in the radial direction on each disk record surface and defines servo-control circular trajectories. In addition to known components, the head positioning control system includes an eccentric information memory for storing eccentric information concerning eccentricities of servo-control circular trajectories on disk record surfaces relative to the center of rotation, and an optimal processing unit that when object disk record surfaces are changed according to an instructed target address, executes processing, which requires the shortest time for accessing a target address, on the basis of eccentric information.

Head positioning control system for disk drives each formed by

Growing community of inventors

Kawasaki, Japan

Yukihiro Uematsu