Magnetic disk apparatus

A magnetic disk apparatus comprising:

• a magnetic head for writing and reading information;
• a magnetic, disk on which information is stored;
• an elastic member for supporting said magnetic head;
• a fixing member for supporting said elastic member;
• a first actuator for coarse movement for moving said magnetic head to a predetermined position over said magnetic disk;
• and
• a second actuator for fine movement arranged between said first actuator and said magnetic head, wherein said second actuator is a plate-shaped structure extending along said magnetic disk which is made of a material having piezoelectric performance and formed by laminating two or more piezoelectric flat plates having a thickness, each of said two or more piezoelectric flat plates having electrodes on upper and lower surfaces, the electrode of at least one of the surfaces among the electrodes existing on said upper and lower surfaces in a piezoelectric flat plate is separated into two or more electrodes, said piezoelectric flat plate has therein a region which is not polarized and two or more polarization regions which are separated by a part of said non-polarized region and are polarized in the thickness direction of said piezoelectric flat plate, and by applying electric fields in the thickness direction of said piezoelectric flat plate to said two or more polarization regions by using said electrodes existing on said upper and lower surfaces of said piezoelectric flat plate, said piezoelectric flat plate is deformed in an in-plane direction of said piezoelectric flat plate, said second actuator having one edge portion along one of said upper and lower surfaces thereof coupled to said fixing member, and an other edge portion along the one of said upper and lower surfaces thereof coupled to said elastic member and said piezoelectric flat plate having recesses formed thereon so as to sandwich the two or more polarization regions in said piezoelectric flat plate therebetween.

A magnetic disk apparatus for writing and reading information on a magnetic disk, comprising:

• a magnetic head for writing and reading information;
• an elastic member for supporting said magnetic head;
• a fixing member for supporting said elastic member;
• a first actuator for moving said magnetic head to a predetermined position over said magnetic disk;
• and
• a second actuator arranged between said first actuator and said magnetic head, wherein said second actuator comprises a piezoelectric flat plate having recesses to sandwich two or more polarization regions in said piezoelectric flat plate.