| 摘要 |
<p>An optical information recording medium comprising a thin plastic substrate of 0.6 mm or thinner, wherein the substrate is protected against strain without being limited by a film structure and a film formation condition. A single-layer or multilayer thin film (70) is formed on a plastic disk-like substrate having a center hole (10). This thin film (70) has a strain relief area (72) inside a recording area (71). This strain relief area (72) is formed by setting an outer diameter of an uncoated inner portion (5) to a value satisfying the following formula (1), for example: A0 ≤ Ax ≤ -0.172P + 0.163 where A0: diameter of center hole, Ax: outer diameter (diameter) of uncoated inner portion, P: total strain occurring in thin film when film forming.</p> |
