Takayuki Munemoto

A dual-stage magnetic disk drive actuator using a piezoelectric device for a high track density

A dual-stage actuator has been developed using a piezoelectric device for a magnetic disk drive with a high track density over 15 kTPI. This actuator uses a VCM (voice coil motor) rotary actuator as a coarse actuator and a piezoelectric actuator installed in a head-arm as a fine actuator. The stroke of the fine actuator is 4.6 mu m, which is sufficient for a track pitch of 1.5 mu m at 17 kTPI. The head position is detected by an optical method using a dot-pattern etched on a disk. The authors describe the design of the dual-stage actuator, including structural analysis, its static and dynamic characteristics, the dual-stage feedback control system. Experimental results of tracking with high accuracy on a 3.5-in disk-drive unit are presented. >

Investigation of 2 Gb/in/sup 2/ magnetic recording at a track density of 17 kTPI

Developments of magnetic head, recording medium, positioning, and signal processing technologies made it possible to perform magnetic recording at an areal density of 2 Gb/in/sup 2/ on a prototype 3.5-in diameter hard disk drive. A track density of 17 kTPI, which is comparable to or even greater than that used in optical storage systems, is used to minimize the reduction in the physical clearance between the medium and the head. The authors outline the system and its component technologies. The read/write characteristics of the 3.5-in prototype disk system are also reported. >

High-density magnetic recording tracking method using a laser diode (and dual-stage actuator)

A novel tracking technology for achieving high track density over 10 k tracks-per-inch (TPI) is developed. Two key technologies are incorporated. One is the application of optical disk technology to a magnetic disk to obtain a high-quality servo signal with a trackwidth 1.5 to 2 mu m. The other is the installation of a dual-stage actuator using a piezoelectric device for the fine actuator to gain higher servo performance in a bandwidth greater than 1 kHz. The authors describe the design of the optical servo system for the track pitch 1.5 mu m, 17 kTPI, and experimental results including a comparison of magnetic heads. >