| 摘要 |
PURPOSE:To make disks exchangeable to each other by specifying the reflectance of an optical disk exclusive for reproducing and making the reflection factor same as those of DRAW type and rewritable type optical disks. CONSTITUTION:The optical disk is composed of a transparent substrate 130, an interference film 141 made of a dielectric and a reflection film 144 made of metal, etc. Reproducing light is made incident from the substrate 130 side. By adding the film 141, the interference of light is generated and a set range can be enlarged for the reflectance of the disk. In such a case, by changing the thickness of the film 141, the reflectance of the disk can be changed. In order to construct an optical memory system equipped with exchangeability to the reflectance of the optical disk exclusive for reproducing, DRAW type and rewritable type optical disks, the reflectance of the optical disk exclusive for reproducing is set at a certain degree exceeding 50% while considering error. When considering efficiency, etc., for utilizing the thermal energy of the light, the reflection factor is more desirable at 52-60%. |
