Read/write head including displacement generating means that elongates and contracts by inverse piezoelectric effect of electrostrictive effect

#The present invention relates to a read/write head, a read/write head positioning mechanism, and a read/write system such as a magnetic or optical disk drive.

#FIG. 32 is a plan schematic illustrative of a flying type magnetic head and a positioning mechanism therefor used in a conventional magnetic or hard disk drive (HDD).

#As shown in FIG. 32, the magnetic head is built up of a slider 2 having an electromagnetic transducer element 1, and a suspension 3 for supporting the slider 2. For the purpose of simplification, interconnecting lines to make electric connections between the electromagnetic transducer element 1 and a signal processing circuit in the hard disk drive for the transmission of read/write signals are not illustrated.

#FIG. 1 is a perspective schematic illustrative of one typical basic construction of the magnetic head according to the present invention, and the positioning mechanism for an electromagnetic transducer element.

#FIG. 2 is a perspective schematic illustrative of one actuator embodiment wherein the actuator is located on the back surface of the slider in the magnetic head according to the present invention.

#FIG. 3 is a perspective schematic illustrative of another actuator embodiment wherein the actuator is located on the back surface of the slider in the magnetic head according to the present invention.

#Features and advantages of the read/write head according to the present invention will now be explained specifically with reference to a magnetic head.

#One exemplary structure of the magnetic head according to the present invention is illustrated in FIG. 1. An actuator 4 is located between a slider 2 having an electromagnetic transducer element 1 and a suspension 3 to make connections between them. The actuator 4 is provided with at least one piezoelectric or electrostrictive material layer having electrode layers on both sides. In the present invention, this layer acts as a displacement generating means. The displacement generating means generates elongation and contraction motions by inverse piezoelectric effect or electrostrictive effect. The elongation and contraction motions in turn cause the displacement of the slider 2 relative to the suspension 3. At this time, the slider 2 is coupled to the actuator 4 in such a direction that the direction of displacement of the electromagnetic transducer element 1 crosses recording tracks, preferably in a direction substantially intersecting the recording tracks at right angles. At the actuator 4 the elongation and contraction of the displacement generating means is controlled by voltage control based on track misregistration signals, so that the electromagnetic transducer element 1 can follow the recording tracks.

#In such an arrangement, the precision of slider positioning by the elongation and contraction of the displacement generating means in the actuator can be 0.1 μm or less. In addition, slider positioning control frequencies can be increased to a few kHz or higher for the reasons that the mass of the slider to be driven by the actuator is much smaller than that of the whole of the magnetic head including an arm, a coil and a suspension that form a conventional positioning mechanism (VCM), the slider is regarded as a rigid body because of being free of spring nature, the driving force the actuator can generate through inverse piezoelectric effect or electrostrictive effect is sufficiently larger than that generated by an electrostatic force actuator having the same amount of displacement, and so on. It is thus possible to increase positioning precision to much higher levels, as compared with a conventional magnetic disk system in which positioning is carried out by use of VCM alone. It is also most unlikely that the disk medium may be adversely affected by a flux leakage which may occur in the case of an electromagnetic force actuator. For an actuator making use of electrostatic force or electromagnetic force, it is required that a movable part be supported by a resilient member having a relatively low rigidity, and so misregistration is likely to occur due to vibrations or shocks. In the present invention, however, such misregistration is unlikely to occur because it is possible to use piezoelectric or electrostrictive ceramics having high rigidity, and the actuator can be coupled to the slider with no resilient member located between them.