Hybrid optical disc construction

Abstract

A hybrid optical recording disc having a substrate and a recording layer disposed over the substrate, the substrate having a read-only (ROM) area in which a groove is modulated by depressions in the substrate and a recordable area in which the groove from the read-only area extends into the substrate in the recordable area. The groove in the read-only area forming wobbling tracks having a depth greater than 170 nm and wherein the depth d2 of the depression in the groove in the read-only area is in a range greater than 170 nm and less than 350 nm.

Dependencies are inferred from the claim text.