Patent ID: 6906993

Claim:
A hybrid optical disc recording medium made from a substrate and laid sequentially on the substrate a dielectric layer, a recording layer, a reflective layer, and a protective overcoat, comprising: a read-only area having a plurality of independent pits with a same depth but of different lengths for generating electric signals when read by machines; and a rewritable area having grooves which have a depth same as that of the pits in the read-only area, the grooves having a bottom which is flat in a middle portion thereof; wherein the depth of pits ranges from {fraction (1/10)} wavelength to ⅕ wavelength, and the pits have a pre-pits width ranging from {fraction (3/16)} track pitch to ½ track pitch; wherein the depth of the grooves ranges from {fraction (1/10)} wavelength to ⅕ wavelength, and the grooves have a width ranging from ½ track pitch to ⅞ track pitch.