Multilayer optical disc

Abstract

A multilayer optical disc which has three or more recording layers and enables easy positioning of a focused beam spot onto a particular recording layer in which a BCA is disposed. An inter-layer distance between a particular recording layer and a recording layer adjacent to the particular recording layer is larger than the other inter-layer distances in which, at the focused beam spot positioning, the focused beam spot traverses the said adjacent recording layer earlier than the other recording layer adjacent to the particular recording layer.

1 . A multilayer optical disc having at least three recording layers, wherein an inter-layer distance between a first recording layer and a second recording layer is larger than another inter-layer distance, information to be first reproduced being recorded in said first recording layer, and said second recording layer being nearest, among recording layers adjacent to said first recording layer, to a disc surface on which a laser beam for recording/reproducing information is to be incident. 
   
   
       2 . A multilayer optical disc according to  claim 1 , wherein said first recording layer is a recording layer farthest from said disc surface on which the laser beam for recording/reproducing information is to be incident. 
   
   
       3 . A multilayer optical disc according to  claim 1 , wherein said first recording layer is a recording layer having a BCA. 
   
   
       4 . A multilayer optical disc having at least three recording layers, wherein an inter-layer distance between a first recording layer and a second recording layer is larger than another inter-layer distance, information to be first reproduced being recorded in said first recording layer, and said second recording layer being farthest, among recording layers adjacent to said first recording layer, from a disc surface on which a laser beam for recording/reproducing information is to be incident. 
   
   
       5 . A multilayer optical disc according to  claim 4 , wherein said first recording layer is a recording layer nearest to said disc surface on which on which a laser beam for recording/reproducing information is to be incident. 
   
   
       6 . A multilayer optical disc according to  claim 4 , wherein said first recording layer is a recording layer having a BCA. 
   
   
       7 . A multilayer optical disc according to  claim 2 , wherein said first recording layer is a recording layer having a BCA. 
   
   
       8 . A multilayer optical disc according to  claim 5 , wherein said first recording layer is a recording layer having a BCA.