INFORMATION RECORDING MEDIUM, INFORMATION REPRODUCING DEVICE, INFORMATION RECORDER, AND INFORMATION RECORDING/REPRODUCING DEVICE

摘要

It is an object of the present invention to provide an information recording medium suitable for high recording density and high recording capacity and capable of generating an RF signal and a push-pull signal the magnitude of which is great enough for an optical disk apparatus using an optical system with an NA of 0.75 or greater. The depth of pits is determined by a trade-off between the level of a push-pull signal used for servo application by a push-pull method and the level of an RF signal as a reproduced signal of information. The depth d is set to be the optimum for a disk system, which has a refractive index n of a medium, an optical wavelength lambda , and an optical system with a NA (Numerical Aperture) of 0.75. The most suitable depth d for both the push-pull signal level and the RF signal level falls within a range of lambda /5.5n≤d≤lambda /4.7n, the second most suitable depth d falls with a range of lambda /5.5n≤d≤lambda /4.5n, and the depth d as the widest standard falls within a range of lambda /8n≤d≤lambda /4.5n.