Patent ID: 8144563

Claim:
An information recording medium comprising: at least three information recording layers, and a base provided between the recording layers, wherein the thickness (D) of the base between the recording layers satisfies a following condition: 100 ×Pw ( n )/ Pw ( n+a )≧−0.1238 ×D 2 −2.772 ×D+ 106.56, where Pw ( n )≦ Pw ( n+a ), Pw(n) is a readout power of a laser beam in reading information from an n th one L(n) of the information recording layers, which are counted sequentially from one of the information recording layers that is located most distant from the data side of the information recording medium, Pw(n+a) is a readout power of a laser beam in reading information from an (n+a) th one L(n+a) of the information recording layers, n is an integer that is equal to or greater than zero, and a is an integer that satisfies n+a≧0 and a≠0.