50-mm CAD-MSR Disk System with Blue Laser

摘要

A mobile magneto-optical disk system with 2 Gbytes user-capacity is proposed. The disk consists of a center aperture detection type of magnetically induced super-resolution medium, a 0.5 mm thickness substrate with 50 mm in diameter, and a newly developed ultraviolet curing resin film to keep the disk tilt small even if its surrounding environmental condition changes. The optics contains a blue laser diode of a 406 nm wavelength and an objective lens with a numerical aperture of 0.6. A laser pulsed magnetic field modulation method is employed and it realizes land and groove recording with an effective track pitch of 0.40μm. Practicable system margin values are confirmed at 0.146μm bit density (11 Gbits/in areal density.)