Optical disk system

摘要: PURPOSE: To accomplish recording and reproducing with high density by specifying the thickness of a light transmissive cover numerical aperture an objective lens in optical disk system where laser beam is condensed on layer through cover. CONSTITUTION: The magneto-optical provided 2 whose aperture(NA) set to be 0.55-0.70 magnetic field generating device 9 modulation consisting glass 8 coil pattern 7 formed. A medium 40 constituted successively laminating dielectric 42, 43, 44, reflection film 45 protective 46 41 0.01-0.6 mm. Thus, since made thin approaches 41, distance between 43 mad close. Therefore, high-density recording/reproducing accomplished capacity large. COPYRIGHT: (C)1991,JPO&Japio