2.5-mm-Thick 10 GB Hard Disk Drive Using 1-inch Single Side Perpendicular Recording

A 2.5-mm-thick head disk assembly (HDA) was made for a capacity of 10 GB using 1-inch single-side perpendicular magnetic recording. Two types of chassis were prepared for investigating capability. All devices were assembled within 2.5 mm thickness on a sufficiently thick base for a block-type HDA, and devices were also assembled on 2.5-mm-thick pressed chassis for a card-type HDA. A 2.4-mm-thick fluid dynamic bearing spindle motor was used for both types of HDAs. The top cover of the chassis was screwed to the fixed central shaft of the spindle motor to ensure the mechanical stability of the card-type HDA. A thin pivot bearing was developed for the HDA. Mechanical simulation revealed that mechanical stability in a 2.5-mm-thick HDA is by no means inferior to that in 5-mm-thick HDA. The areal density of 200 Gb/in² was found in a spin stand using CoCrPt-SiO₂-based a perpendicular medium and a TuMR magnetic head. A new servo track writer was developed for thin HDAs using highly accurate laser scales. A servo signal with a track pitch of 100 nm (250 kTPI) was written on a block-type HDA. Track-pitch positioning accuracy of plusmn7% was achieved at a track pitch of 150 nm (169 kTPI) for both types of HDAs. Write and read performance was investigated in the hard disk assembly combined with printed circuit board