Method and system for recording/reproducing information on/from a recording optical disc

摘要

The invention concerns methods for recording and/or reproducing information on/from a recording layer (33) of an optical disc by using an optical disc having said recording layer (33) behind a substrate (30,31) of 0.6 mm thickness. An important step of such methods is focusing a laser light on said recording layer (33) by use of a focusing lens (18) of a numerical aperture (NA) in the range of >0.53 to ≤0.65. The invention includes as well a related system comprising an optical recording and/or reproducing apparatus and an optical disc, said optical disc comprising a first substrate (30), a second substrate (31), and a recording and/or reproducing layer (33) sandwiched between said first substrate (30) and said second substrate (31) and being provided on tracks (35,36) formed on the inner surface of such substrate having a thickness of 0.6 mm, said apparatus comprising focusing means (18) for focusing laser light on said recording and/or reproducing layer (33) by a focusing lens (18) of a numerical aperture (NA) in the range of >0.53 to ≤0.65.