In the tussle between Blu-ray and HD-DVD, one of the important factors in deciding the winner will be capacity. Blu-ray currently holds the crown, with a two-layer 50GB disc as part of the official standard. HD-DVD will have a 3-layer 45GB disc.

Sharp, on the other hand, has developed a two-layer, 100GB disc, twice the capacity per-layer than Blu-ray. Matsushita has already developed a 100GB disc, but it uses four layers, not two.

Sharp may design its future high-capacity discs to meet Blu-ray Disc specs, said a spokesman.

Sharp’s super-resolution functional film enables a blue laser beam to read out smaller pits than its beam spot. In Sharp’s prototype, the beam spot is 0.4 micron and pits are 0.1-micron diameter with 0.1-micron interval. The beam covers two pits simultaneously, but the super-resolution functional film lowers its reflection rate when it is heated.

Using the film for the upper layer, Sharp researchers verified the signal read out of both super resolution functional films, which have 0.1-micron diameter pits, about two-thirds of the minimum pit of the Blu-ray Disc pit (0.149 microns).

Link: InformationWeek - Sharp Develops 100-Gbyte Optical Disk