Premastered Optical Disk by Superresolution Using Rear Aperture Detection

Premastered optical disk by superresolution (PSR) using rear aperture detection (RAD) has been realized. The PSR disk has a chalcogenide material. Using PSR by RAD with a current CD system, we demonstrated the feasibility of increasing both the linear density and the track density of read only memory (ROM) optical disks. By superresolution in the linear direction, a high C/N of 47 dB was obtained for a pit length of 0.3 µm which is beyond the optical limit. Furthermore, by superresolution in the track direction, a low crosstalk of -38 dB and a wider margin of radial skew angle compared to conventional detection were obtained for a track pitch of 1.1 µm.