Rewritable optical disk system with over 10 GB of capacity

Using a two-element objective lens, over 0.9 NA lens and long WD lens are demonstrated. Using a thin cover layer, problems for skew margin and thickness tolerance are solved. Using a red LD, a 0.85 NA lens and a 0.1 mm cover PC disk, 8 GB rewritable disk system has been developed. Using a blue-green LD and an SHG blue laser, promising results are demonstrated for 12 GB and 17 GB of capacity.