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Wireless suspensions have been developed to improve the reliability of magnetic disk drives that use MR heads and pico-sliders. In this paper, we first consider what features are required for suspensions. We next investigate the characteristics in two types of wireless suspensions, a small two-piece suspension and a large conventional sized three-piece suspension. Finally, we demonstrate the advantages of the small two-piece suspension. Index Terms - Disk drive, HDI, shock, slider, stability, and suspension.

To achieve an ultralow flying height for magnetic heads, we developed a super proximity trapezoid shaped slider having leading edge width narrower than the trailing edge width. Compared to a conventional slider, it has lower inertia and mass and can maintain a higher roll stiffness. Therefore, it can reduce the impact force resulting from scattered projections on disk surfaces. In addition, it can reduce the flying height fluctuations due to slider rail irregularities, because it is supported at three points by air pressure. As a result, its flying stability is highly reliable.

An optimization method for magnetic disk drive suspensions that improves resonant frequencies in the access direction is described. The basic principles of this method are widening the node portions and narrowing the loop portions of a suspension in the sway mode. The frequency response characteristics were predicted with an precision analysis, which included deformation of the loaded suspension. These methods were applied to an integrated head suspension system, named pico-CAPS, We confirmed that the resonant frequency of the sway mode was higher than 10kHz, with an increase of 20%, and also confirmed the validity of these methods.

Ultralow load force pico-sliders must be reed to further improve the reliability of magnetic disk drives. We now propose a new integrated suspension for pico-sliders with MR heads, called pico-CAPS. The pico-CAPS features a monolithic body and has a direct signal pattern. It is light and has ultralow stiffness and a high resonant frequency. Our tests show that the pico-CAPS makes the flying pico-slider stable. Its shock resistance is high, and its electrical characteristics allow the high data transfer rate of over 40 MB/s.

A write frequency has been increasing by improvement of a write driver and a write head for higher transfer rate in hard disk drives. A certain method for high write frequency operation is to put a write driver chip on the suspension. We designed a chip-on-cable-patterned suspension (C-CAPS) that is an integrated wireless suspension with a write driver chip on. This paper describes the first observation of the effect on the chip-on-suspension in the write frequency and what type of the C-CAPS is suitable, especially relating to the location of a chip, for high performance hard disk drives. Next, we clarify characteristics of the C-CAPS, such as write current transition time, interface between the chip and disk, shock resistance, frequency response, thermal deformation due to temperature increase of the chip, and static attitude change due to bonding the chip. We conclude the C-CAPS contributes to increase a write frequency and the best location of a chip is on the tip of the load beam for high performance hard disk drives. Index Terms--Hard disk drive, suspension, head, slider, write driver, chip, write current transition time, resonant frequency, shock resistance, static attitude, thermal deformation, CAPS, flying height.