HIGH-DENSITY DUAL-LAYER OPTICAL DISC

摘要

A high-density dual-layer optical disc of the present invention is configure d so that the first substrate thickness from the light incidence surface of a transparent substrate to the first recording layer is equal to a value obtained by subtracting half the distance between the first and the second recording layers from the substrate thickness from the light incidence surfa ce of a transparent substrate to a recording layer in a general high-density single layer optical disc, and the second substrate thickness from the light incidence surface to the second recording layer is equal to a value obtained by adding half the distance between the two recording layers to the substrat e thickness from the light incidence surface to the recording layer in the general high-density single layer optical disc.