Optical information recording medium, optical information recording method, and optical information recording apparatus

Abstract

An information recording medium according to the present invention includes a plurality of recording layers, and a test area for determining a recording power of a laser light for each of the plurality of recording layers, in which a first test area of a first layer and a second test area of a second layer adjacent to the first layer are provided at different radial positions.

1 . An optical information recording medium, comprising:
 a first information recording layer on which information is to be recorded by laser light;   a second information recording layer on which information is to be recorded by the laser light which has passed through the first information recording layer,   wherein:   the first information recording layer includes a first test-recording area for performing a test recording operation on the first layer, and at least one of a reproduction-only area and a recording and reproduction area,   the second information recording layer includes a second test recording area for performing a test recording on the second layer, wherein a start location of the first test recording area is radially offset from a start location of the second test recording area, and   at least one of the reproduction-only area and the recording and reproduction area, and the second test recording area is located such that, for all test recording performed on the second information recording layer, only one of the reproduction-only area and the recording and reproduction area includes an area of the first information recording layer through which the laser light for recording information in the second test recording area passes,   further comprising a separation layer for separating the first information recording layer and the second information recording layer from each other, wherein:   the area of the first information recording layer, through which the laser light for recording information in the test recording area passes, extends outward from an outer end of an area of the first information recording layer corresponding to the test recording area by a length δ, the length δ being represented by:
   δ= d ·tan(sin −1 (NA/ n )), 
   
       where d is a distance in a thickness direction between the first information recording layer and the second information recording layer; n is a refractive index of the separation layer; and NA is a numerical aperture of an objective lens for focusing the laser light to the test recording area; and
 wherein the second information recording layer has a data recording area which extends from an end of the test recording area by at least the length δ. 
 
     
     
         2 . An optical information recording medium, comprising:
 a first information recording layer on which information is to be recorded by laser light; and   a second information recording layer on which information is to be recorded by the laser light which has passed through the first information recording layer,   wherein:   the first information recording layer includes a first test-recording area for performing a test recording operation on the first layer, and at least one of a reproduction-only area and a recording and reproduction area,   the second information recording layer includes a second test recording area for performing a test recording on the second layer, wherein a start location of the first test recording area is radially offset from a start location of the second test recording area,   at least one of the reproduction-only area and the recording and reproduction area, and the second test recording area is located such that, for all test recording performed on the second information recording layer, only one of the reproduction-only area and the recording and reproduction area includes an area of the first information recording layer through which the laser light for recording information in the second test recording area passes;   further comprising a separation layer for separating the first information recording layer and the second information recording layer from each other, wherein:   the area of the first information recording layer, through which the laser light for recording information in the test recording area passes, extends outward from an outer end of an area of the first information recording layer corresponding to the test recording area by a length δ, the length δ being represented by:
   δ= d ·tan(sin −1 (NA/ n )), 
   where d is a distance in a thickness direction between the first information recording layer and the second information recording layer; n is a refractive index of the separation layer; and NA is a numerical aperture of an objective lens for focusing the laser light to the test recording area; and   wherein the area of the first information recording layer, through which the laser light for recording information in the test recording area passes, extends outward from the outer end of the area of the first information recording layer corresponding to the test recording area by a length δ′, the length δ′ being represented by:
   δ′= d ·tan(sin −1 (NA/ n ))+δ m    
   
       where δm is a maximum positional offset distance between the first information recording layer and the second information recording layer. 
     
     
         3 . An optical information recording medium according to  claim 2 , wherein the second information recording layer includes a data recording area which extends from the end of the test recording area by at least the length δ′. 
     
     
         4 . An optical information recording medium, comprising:
 a first information recording layer on which a signal is to be recorded by laser light;   a second information recording layer on which a signal is to be recorded by laser light which passes through the first information recording layer;   wherein:   the first information recording layer includes a first predetermined area for performing a test recording operation on the first layer, and at least one of a reproduction-only area and a recording and reproduction area;   the second information recording layer includes a second predetermined area for performing a test recording on the second layer, wherein a start location of the first predetermined area is radially offset from a start location of the second predetermined area;   at least one of the reproduction-only area and the recording and reproduction area is positioned on the first information recording layer so that, for all test recording performed on the second information recording layer, laser light for recording a signal in the second predetermined area of the second information recording layer passes through only one of the reproduction-only area and the recording and reproduction area of the first information recording layer; and   further comprising a separation layer provided between the first information recording layer and the second information recording layer, wherein:   an area of the first information recording layer, through which the laser light for recording the signal in the predetermined area of the second information recording layer passes, includes an area having a length δ and extending from an end of an area of the first information recording layer corresponding to the predetermined area of the second information recording layer, the length δ being represented by:
   δ= d ·tan(sin −1 (NA/ n )) 
   wherein d is a distance in a thickness direction between the first information recording layer and the second information recording layer; n is a refractive index of the separation layer; and NA is a numerical aperture of an objective lens for focusing the laser light to the predetermined area; and   wherein the second information recording layer has a data recording area which extends from an end of the predetermined area by at least the length δ.