Patent ID: 8634287

Claim:
A manufacturing method for a read-only optical disc medium, comprising: forming a concavo-convex shape on an information recording surface according to a first modulation signal by a shaping process; covering the information recording surface with a reflective film by a deposition process; forming a recording track in which the concavo-convex shape is provided as a first recording data sequence formed by pits and lands; forming an additional-information recording area in which the information recording surface is flat on the information recording surface and in the recording track in which the first recording data sequence is formed by the pits and the lands in the shaping process; and forming a second recording data sequence by marks, which are formed by erasing or reducing the reflective film according to a second modulation signal, in the additional-information recording area on the information recording surface after the deposition process, and wherein formation of the first recording data sequence and formation of the second recording data sequence are performed so that the minimum level of reproduction signal amplitude in the first recording data sequence and the minimum level of reproduction signal amplitude of the second recording data sequence are substantially equal when laser light is applied onto the first recording data sequence and the second recording data sequence.