| 摘要 |
PURPOSE:To improve the C/N ratio by increasing the modulating degree of amplitudes. CONSTITUTION:An optical data recording medium 10 is a rewritable optical data recording medium, having a multi-layered lower protecting film 2 of four layers, a recording film 3, an upper protecting film 4 and a reflecting film 5 sequentially layered on a surface of a substrate 1 where a pregroove is formed. At the opposite surface is formed a multi-layered reflection preventing film 6 of a reflection preventing film (I) 6a and a reflection preventing film (II) 6b. Owing to the multi-layered reflection preventing film 6, the cast light is never reflected at the surface of the substrate in the optical data recording medium 10. Accordingly, the reflectance of a part of a lower reflectance of a recorded part or an erased part of the recording film can be decreased without lowering the reflectance of a higher reflectance of the recorded part or erased part of the recording film of the optical data recording medium. Eventually, the modulating degree of amplitudes of the optical data recording medium can be increased, thereby improving the C/N ratio and reducing reading errors. |
