| 摘要 |
PURPOSE:To provide the write-once type CD which can be produced without selective coating of dyes and has a ROM layer. CONSTITUTION:This recording medium consists of the layer constitution successively provided with a light absorptive layer 2 essentially consisting of the dyes, a reflection layer 3 and a protective layer 4 on a substrate 1 formed with prepits and guide grooves on its surface. The sectional profile of the prepits is formed into an approximately trapezoidal shape and the sectional profile of the guide groove to an approximately V-shape. The depth of the prepits and the guide grooves and the depth of the prepit parts and guide groove parts at the boundary of the light absorptive layer 2 and the reflection layer 3 are so controlled that the optical phase differences of the prepit parts and the guide groove parts attain respectively specific ranges. |
