Dual Layer Phase Change Optical Disk Using Limit Equalizer

A simple manufacturing process of multilayer recording disks has been developed to fabricate a large-capacity optical disk of more than 40 GB, using a short-wavelength laser diode and high numerical aperture (NA) objective lens. Some existing production facilities for the digital versatile discs (DVD) are applicable to this process. These disks can be utilized for long-time video recording of high-definition TV broadcasting. We have developed a dual-layer rewritable optical disk with capacity of more than 43 GB per one side of a 120 mm disk by this process. We obtained good performance of playback jitter for disks of 43 GB and 46.6 GB capacities with on-groove recording and limit equalizer at a user data transfer rate of 36 Mbps as well as good direct overwriting characteristics over 1,000 cycles.