OPTICAL RECORDING MEDIUM AND ITS RECORDING AND REPRODUCING METHOD

摘要

PROBLEM TO BE SOLVED: To obtain an optical recording medium having low noise and high CNR of recording signal. SOLUTION: The optical recording medium is formed by providing an information layer containing at least a recording layer on a substrate having groove parts and inter-groove parts each placed between the adjacent groove parts to each other, the cross-section of substrate vertical to the extended direction of the groove is shaped so that a recessed curved surface and a projecting curved surface are alternately continued and when the interval of the center of the grooves adjacent to each other is expressed by TP as a groove pitch and the sum total of the length of a set of the groove part and a flat part of the inter-groove part adjacent to each other is expressed by F as the flat part, the flat part F is <=45% of the groove pitch TP.