| 摘要 |
<P>PROBLEM TO BE SOLVED: To make a recording density higher and a recording capacity greater by forming an information recording medium, such as an optical disk, in such a manner that an RF signal and push-pull signal of sufficient magnitude can be formed by an optical disk device using an optical system of, for example, ≥0.75 in NA. <P>SOLUTION: The depth of the pits 13a on the medium 15 is determined to balance with the level of the RF signal which is a reproduced signal of information. The depth d is so set as to be optimum for a disk system, wherein the refractive index of the medium 15 is n, the optical wavelength is λ and the aperture ratio of the optical system as 0.75. The most desirable depth of the pits for both the push-pull signal and the RF signal level is in a range of λ/5.5n≤d≤/λ/4.7n, the next depth ranges from λ/5.5n≤d≤//4.5n to λ/8n≤d≤/λ/4.7n and the least strict depth in terms of specifications is in a range of λ/8n≤d≤/λ/4.5n. <P>COPYRIGHT: (C)2004,JPO |
