Three-dimensional recording and reproducing apparatus

Abstract

A recording medium including a plurality of recording layers, including: an optional first recording layer on which a light spot at a diffraction limit is formed; and a second recording layer on which a mark string pattern is formed, said second recording layer being different from said first recording layer, wherein when said mark string pattern is formed on a light receiving plane, while information of said first recording layer is reproduced, assuming that an optical distance between said first and second recording layers is dm, an optical distance d between optional two recording layers among a plurality of said recording layers is different from said dm.

1 . (canceled) 
   
   
       2 . An optical disc having a plurality of recording layers to which information is recorded as mark pattern formed by an irradiation of a light spot that is emitted from an optical head employing a light source, an optical detector, an optical system for imaging reflected light from the optical disc to a light receiving plane of the optical detector, comprising:
 a substrate;   a plurality of recording layers formed on the substrate with an intermediate layer therebetween;   wherein an optical spot at a diffraction limit is formed on a target recording layer among said plurality of recording layers at a time of recording information; and   a distance between said target recording layer and a neighboring recording layer is designed to not include a distance of which a mark pattern in a recording layer different to the target recording layer is imaged to the light receiving plane of the optical detector.   
   
   
       3 . An optical disc having a plurality of recording layers to which information is recorded as a mark pattern formed by an irradiation of a light spot that is emitted from an optical head employing a light source, an optical detector, an optical system for imaging reflected light from the optical disc to a light receiving plane of the optical detector, comprising:
 a substrate;   a plurality of recording layers formed on the substrate with an intermediate layer therebetween;   wherein an optical distance d between one of the plurality of recording layers and its neighboring recording layer is different to dm,   where dm is an optical distance that a mark pattern in recording layers different to said one of the recording layers is imaged to the light receiving plane of the optical detector.