High C/N magneto-optical disks using plastic substrates for video image applications

High carrier to noise ratio (C/N) magneto-optical disks for analog video image applications are described. Optimized TbFeCo recording layer and Si 3 N 4 protective and spacing layers are fabricated on 200mmφ plastic pre-grooved substrates. A protective cover is sandwiched with a 0.5mm air gap. Recording, reading and erasing are performed through the protective cover. More than 55dB C/N at a 5 MHz frequency, a necessary condition for analog video component recording, is achieved, and a 49 dB video S/N is obtained.