OPTICAL RECORDING MEDIUM, MASTER DISK FOR PRODUCTION OF OPTICAL RECORDING MEDIUM AND OPTICAL RECORDING AND REPRODUCING DEVICE

摘要

PROBLEM TO BE SOLVED: To increase track density and to obtain high recording density by forming a single spiral recording track in an optical recording medium on which a groove is formed along the recording track. SOLUTION: A groove is formed in a single spiral form along a recording track. The groove is obtained by alternately forming a shallow portion and a deep portion along the recording track in such a manner that the shallow groove G1 and deep groove G2 are adjacent to each other in a direction perpendicular to the recording track. By forming the shallow groove G1 and deep groove G2 adjacent to each other, signals required for recording and reproducing can be obtained in a high level even when track pitch is decreased.