Seiji Morita

Super-High-Density Optical Disk Using Deep Groove Method.

An optical disk with a deeper-than-usual groove has been manufactured. The deeper the groove, the less cross-erase occurs. By adjusting the groove depth, cross-erase is suppressed even if the track pitch is narrowed to 0.5 µm. Also, we found another groove depth which cancels both cross-talk and cross-erase. Finally, we obtained a high-density optical disk with a deep groove, the track pitch and the minimum mark length of which are 0.5 µm and 0.35 µm, respectively.

Deep groove method on high density optical disk memory

Recently, standardization of the DVD-RAM and that of the 8/spl times/130 mm MO are about to be finalized. These standardizations are expected to accelerate the use of optical disks in the area of multi-media. To achieve higher density optical disks, it is necessary to narrow the track pitch without working at shorter wavelengths. This paper describes an optical disk in which data is recorded on both lands and grooves with a reduced track pitch and a deeper-than-usual groove, a technique we call the deep groove (DG) method.

High quality optical disc stampers with round edge grooves

We describe a deep groove having round edges in the optical disc substrate as one of solutions for difficulty in injection molding. The round edge deeper grooves were actually made and tested. Stampers with the round edge grooves can be easily made by modified directly engraved glass mastering. Replication separability from the stamper is markedly improved. No cloud problem, shorter cycle time at replication process and longer lifetime of stampers were confirmed.