OPTICAL RECORDING MEDIUM, ITS MANUFACTURING METHOD, AND RECORDING/REPRODUCING METHOD

摘要

An optical recording medium having a capacity equivalent to DVD-ROMs and an adequate focusing characteristic even at high linear velocities above 4x velocity, free of in-plane variation of degree of modulation, and having a high reliability. A method for manufacturing such an optical recording medium and a recording/reproducing method are also disclosed. The optical medium comprises a substrate, a recording layer, and a reflective layer both formed over the substrate. A preset center value of the thickness is given to the substrate. When the thickness of the substrate is within a predetermined range from the preset center value, the axial acceleration of the optical recording medium has a maximum allowable value. As the deviation from the preset center value exceeding the predetermined range increases, the maximum allowable value of the axial acceleration decreases.