Patent ID: 7885171

Claim:
An information storage medium with n information storage layers (where n is an integer that is equal to or greater than three), on which data can be written with a laser beam and which are stacked one upon the other, wherein each of the n information storage layers has a test write zone for determining the recording power of the laser beam, and wherein when those n information storage layers are counted from the one that is located most distant from the surface of the medium on which the laser beam is incident, there is a bigger radial location difference between the outer peripheral end of the inner one of the test write zones of i th and (i+1) th information storage layers (where i is an integer that satisfies 2≦i≦n−1) and the inner peripheral end of the other outer test write zone than between the outer peripheral end of the inner one of the test write zones of j th and (j+1) th information storage layers (where j is an integer that satisfies 1≦j≦i−1) and the inner peripheral end of the other outer test write zone.