| 摘要 |
PURPOSE:To provide sufficient output and C/N even if the optical recording medium of a large-diameter size is rotated at a high speed by using a substrate consisting of specific cyclic polyolefin. CONSTITUTION:This medium is provided with a recording layer on the substrate which is made of a resin contg. the cyclic polyolefin copolymerized with ethylene and cyclic olefin expressed by the formula and has >=200mm diameter. The medium is subjected to recording and reproducing at >=1800rpm rotating speed. In the formula, n denotes or positive integer; R<1> to R<12> denote H, halogen or hydrocarbon. Tetracyclo[4,4,0,1<2.5>,1<7.10>]-3-dodecene, etc., are usable as the cyclic polyolefin. The recording layer contg. dyes is laminated directly or via an underlying layer on the substrate and these layers are preferably formed by a vapor phase film forming method. |
