Optical disk, recording/reproducing method thereof, and optical disk apparatus with employment of optical disk

摘要

Then, in order to achieve the above-described object, in the optical disk of the present invention, while micro-hologram layers 7 and 8 made of plural layers are provided in an inner portion of a plate body 2 along a thickness direction of the plate body 2, dimensions of micro-holograms 4 along the thickness direction of the plate body 2, which configure the micro-hologram layer 7 formed on the side of one surface of the plate body 2 within the micro-hologram layers 7 and 8 constructed of the plural layers, are made smaller than dimensions of micro-holograms 3 along the thickness direction of the plate body 2, which configure a micro-hologram layer 8 formed on the side of an inner layer of the plate body 2.