| 摘要 |
<p>A DVD-R has a land (1) and a groove (2) alternately formed in a spiral form, where the land (1) constitutes a projected section, and the groove (2) a recessed section. The groove (2) carries record information, and a part of the land (1) has land prepits (3). The land prepits (3) form a recessed section, where each land prepit (3), as illustrated, completely covers the land (1) in the width direction. If the maximum length of the land prepit is (a), and the minimum length (the shorter one of land prepit lengths (b1, b2) normally in the land periphery (boundary with the groove) is (b), b > 0.5 x a. The value of (a) is 0.2 νm-0.4νm.</p> |
