Development of Compact Disk-Write-Once Hybrid Disk

We developed the new hybrid disk which has a read-only area (ROM), that is, a premastered area, and write-once area (WO), where writing is possible. To be compatible with a compact disk (CD), the disk is a single plate and organic dye is used for the recording layer. The disk has high productivity because there is the possibility of spin-coating the organic dye onto not only the WO area but to pits in the ROM area as well. Furthermore, the disk can have multiple ROM and WO areas as the user's option. To satisfy the CD standards a high reflection rate is achieved by means of characterizing the shape of pits in the ROM area and pregrooves in the WO area. The disk yields good CD playback signals after recording.