Super-High Density Optical Disk using Deep Groove method

Abstract

For the purpose to achieve large capacity and high density of optical disks, it is indispensable to narrow the track pitch. The track pitch decides the distance between recorded marks on a track and the adjacent track. To narrow the track pitch, the following two technical issues should be settled. One of the issues is the optical cross-talk from the adjacent track, the other is the thermal cross-talk to the adjacent track. (This thermal cross-talk is often called “cross-erase”.) For suppressing the optical cross-talk, the land/groove recording method1)and the magnetic super-resolution method2)have already been reported. Meanwhile, there is no report which clarifies how to decrease the thermal cross-talk. In the actual cases, the lower limit of the track pitch depends on the thermal cross-talk3). This paper describes the suppression of the thermal cross-talk by adjusting the groove depth more deeply. We call this technology “Deep Groove method”.